Modelling the performance of a calorifier installed at a university residence intended to be retrofited by an air source heat pump
- Mzolo, Noluthando Precious Duduzile
- Authors: Mzolo, Noluthando Precious Duduzile
- Date: 2017
- Subjects: Caloric engines Heat pumps
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4660 , vital:28485
- Description: Sanitary hot water production contributes significantly to the electrical energy consumption in the university campus. An in-depth understanding of the current hot water technology, number of students, capacity of water used per student, time of use of hot water, total volume of hot water consumed and the total energy used on an average weekday in a university residence are very crucial in opting for energy efficient technology like an air source heat pump (ASHP) water heater. The study focused on quantitative and qualitative analysis of data collected for the hot water profiles in one of the university residences (Elitheini 1) from the conduction of experiment and questionnaires. The results revealed that 94% of the 75 students used hot water during the Eskom morning peak and 61% during the Eskom evening peak. In addition, the average daily energy consumption of the 12 kW Calorifier was 139.49 kWh, while the measured volume of hot water usage was 1950 L which is in strong agreement with the total volume (1945 L) of hot water consumption from the questionnaires. The p-value of the average volume of hot water usage measured by experiment and questionnaires was 0.7 and is of no mean significant difference. The monthly energy consumption for the week days was projected to be 2929.31 kWh. By retrofitting of calorifier with an ASHP unit, the energy consumption could reduce to 976.43 kWh based on its consecutive coefficient of performance of 3. Finally, from the energy consumption reduction analysis and the current Eskom tariffs, it can be alluded that the payback period of the proposedASHP unit as a retrofit to the calorifier is going to be less than 2 years and is worthy to invest into such technology under this study due to its favourable payback period and the reliability and lifespan of the ASHP unit.
- Full Text:
- Date Issued: 2017
- Authors: Mzolo, Noluthando Precious Duduzile
- Date: 2017
- Subjects: Caloric engines Heat pumps
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4660 , vital:28485
- Description: Sanitary hot water production contributes significantly to the electrical energy consumption in the university campus. An in-depth understanding of the current hot water technology, number of students, capacity of water used per student, time of use of hot water, total volume of hot water consumed and the total energy used on an average weekday in a university residence are very crucial in opting for energy efficient technology like an air source heat pump (ASHP) water heater. The study focused on quantitative and qualitative analysis of data collected for the hot water profiles in one of the university residences (Elitheini 1) from the conduction of experiment and questionnaires. The results revealed that 94% of the 75 students used hot water during the Eskom morning peak and 61% during the Eskom evening peak. In addition, the average daily energy consumption of the 12 kW Calorifier was 139.49 kWh, while the measured volume of hot water usage was 1950 L which is in strong agreement with the total volume (1945 L) of hot water consumption from the questionnaires. The p-value of the average volume of hot water usage measured by experiment and questionnaires was 0.7 and is of no mean significant difference. The monthly energy consumption for the week days was projected to be 2929.31 kWh. By retrofitting of calorifier with an ASHP unit, the energy consumption could reduce to 976.43 kWh based on its consecutive coefficient of performance of 3. Finally, from the energy consumption reduction analysis and the current Eskom tariffs, it can be alluded that the payback period of the proposedASHP unit as a retrofit to the calorifier is going to be less than 2 years and is worthy to invest into such technology under this study due to its favourable payback period and the reliability and lifespan of the ASHP unit.
- Full Text:
- Date Issued: 2017
Early stage ichthyofauna from shallow water habitats of the Angola-Benguela frontal zone
- Authors: Farthing, Matthew William
- Date: 2017
- Subjects: Fishes -- Larvae -- South Africa -- Atlantic coast , Fishes -- Larvae -- Angola -- Atlantic coast , Striped mullet -- Angola -- Atlantic coast
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50442 , vital:25988
- Description: Early stage fishes (larvae and early juveniles) were collected from an array of shallow water (±1.5m) habitats on the warm-temperate southern Angolan coastline between June 2014 and June 2015. This study, the first assessment of the early stages of coastal fishes in Angola, provides important new understanding of non-estuarine shallow water nursery habitat use by coastal fishes from the region. In total, 51 species from 18 teleost families were observed. The exposed surf zone was dominated by postflexion larvae, while the moderately exposed beach and sheltered bay were dominated by early juveniles. Both fish density and diversity peaked in the wet season (Feb – Apr 2015) for all habitats, attributed to the influx of summer spawning species. Diplodus sargus dominated catches from the exposed surf zone, and the timing of observations supports the growing consensus that sparid spawning is dictated by temperature, not season. The similitude of the observed species to those observed in warm temperate South Africa highlights the historical connection of the warm-temperate study area with warm-temperate South Africa, prior to the formation of the Benguela Current as a vicariant barrier. The classification of the study assemblage into established estuarine utilization categories showed that the surf zone hosted more exclusively marine species than comparable surf zones in South Africa, attributed to the absence of estuaries in southern Angola. However, the observation of the marine estuarine dependent Mugil cephalus in this study area devoid of estuaries suggests that estuarine dependency may be regionally specific for some taxa. It appears that the warm, sheltered, nutrient rich waters of Tombua Bay provide typically estuarine associated taxa with a suitable alternative, non-estuarine nursery habitat. This study provides evidence that the importance of estuaries as critical nursery habitats has been overemphasized for some warm-temperate coastal fishes. However, the absence of other marine estuarine dependent species from the study area suggests that some warm-temperate taxa do intrinsically rely on estuarine function for survival.
- Full Text:
- Date Issued: 2017
- Authors: Farthing, Matthew William
- Date: 2017
- Subjects: Fishes -- Larvae -- South Africa -- Atlantic coast , Fishes -- Larvae -- Angola -- Atlantic coast , Striped mullet -- Angola -- Atlantic coast
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50442 , vital:25988
- Description: Early stage fishes (larvae and early juveniles) were collected from an array of shallow water (±1.5m) habitats on the warm-temperate southern Angolan coastline between June 2014 and June 2015. This study, the first assessment of the early stages of coastal fishes in Angola, provides important new understanding of non-estuarine shallow water nursery habitat use by coastal fishes from the region. In total, 51 species from 18 teleost families were observed. The exposed surf zone was dominated by postflexion larvae, while the moderately exposed beach and sheltered bay were dominated by early juveniles. Both fish density and diversity peaked in the wet season (Feb – Apr 2015) for all habitats, attributed to the influx of summer spawning species. Diplodus sargus dominated catches from the exposed surf zone, and the timing of observations supports the growing consensus that sparid spawning is dictated by temperature, not season. The similitude of the observed species to those observed in warm temperate South Africa highlights the historical connection of the warm-temperate study area with warm-temperate South Africa, prior to the formation of the Benguela Current as a vicariant barrier. The classification of the study assemblage into established estuarine utilization categories showed that the surf zone hosted more exclusively marine species than comparable surf zones in South Africa, attributed to the absence of estuaries in southern Angola. However, the observation of the marine estuarine dependent Mugil cephalus in this study area devoid of estuaries suggests that estuarine dependency may be regionally specific for some taxa. It appears that the warm, sheltered, nutrient rich waters of Tombua Bay provide typically estuarine associated taxa with a suitable alternative, non-estuarine nursery habitat. This study provides evidence that the importance of estuaries as critical nursery habitats has been overemphasized for some warm-temperate coastal fishes. However, the absence of other marine estuarine dependent species from the study area suggests that some warm-temperate taxa do intrinsically rely on estuarine function for survival.
- Full Text:
- Date Issued: 2017
Impacts of African elephant feeding on white rhinoceros foraging opportunities
- Authors: Prinsloo, Dominique
- Date: 2017
- Subjects: Herbivores -- Ecology -- South Africa , Grassland ecology -- South Africa Animal-plant relationships -- South Africa Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13768 , vital:27306
- Description: In this study, I investigated the interaction between two megaherbivores, the African elephant and white rhinoceros, that has the potential to impact grazing lawns of which white rhino are the creators and maintainers and elephants are potentially the modifiers. I hypothesized that as elephants browse, they discard a variety of coarse woody debris onto the ground; should this woody debris (of varying amounts and sizes) fall onto grazing lawns, white rhino either move them, consume grass around the woody debris or abandon the lawn entirely. If high levels of woody debris are deposited here, grazing by white rhino is likely to be prevented, at which time I predicted that mesoherbivores would have a competitive advantage in accessing forage that white rhino cannot. I examined the mechanistic links between different levels of elephant-deposited woody debris and grass response at a point scale and feeding patch spatial scale of grazing lawns in an African savanna. In addition, I assessed the response of mesoherbivores in terms of vigilance behaviour with increasing levels of predation risk posed by increasing levels of woody debris. I present the first evidence of an indirect effect of elephant on white rhino foraging behaviour. I demonstrate how increasing levels of woody debris lead to a decreasing probability of foraging by white rhino. I also demonstrate how the probability of foraging by mesoherbivores increases as the amount of forage increases. However, since this study took place during a severe drought where resources are extremely limited, I was unable to properly separate the effects of elephant-deposited woody debris from the severe lack of rainfall on grass response and subsequently herbivore foraging behaviour. Due possibly to the drought, mesoherbivores responded less or not at all to risk factors such as woody debris therefore woody debris was not a predictor of vigilance behaviour in my study. This study contributes to our understanding of how the impacts of elephants, as ecosystem engineers, have cascading effects on savanna ecosystems. My study showed that elephant impact mediates the foraging behaviour of white rhino during a drought. However, under average rainfall periods, my original hypothesized effect of the indirect impacts of elephants on white rhino foraging and grazing lawn dynamics could still hold. This key hypothesis that I was unable to test under ‘normal’ conditions due to the drought is still valid and functionally important for understanding the ecosystem processes driving grazing lawn formation, persistence and composition in African savannas where elephants and white rhinos coexist.
- Full Text:
- Date Issued: 2017
- Authors: Prinsloo, Dominique
- Date: 2017
- Subjects: Herbivores -- Ecology -- South Africa , Grassland ecology -- South Africa Animal-plant relationships -- South Africa Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13768 , vital:27306
- Description: In this study, I investigated the interaction between two megaherbivores, the African elephant and white rhinoceros, that has the potential to impact grazing lawns of which white rhino are the creators and maintainers and elephants are potentially the modifiers. I hypothesized that as elephants browse, they discard a variety of coarse woody debris onto the ground; should this woody debris (of varying amounts and sizes) fall onto grazing lawns, white rhino either move them, consume grass around the woody debris or abandon the lawn entirely. If high levels of woody debris are deposited here, grazing by white rhino is likely to be prevented, at which time I predicted that mesoherbivores would have a competitive advantage in accessing forage that white rhino cannot. I examined the mechanistic links between different levels of elephant-deposited woody debris and grass response at a point scale and feeding patch spatial scale of grazing lawns in an African savanna. In addition, I assessed the response of mesoherbivores in terms of vigilance behaviour with increasing levels of predation risk posed by increasing levels of woody debris. I present the first evidence of an indirect effect of elephant on white rhino foraging behaviour. I demonstrate how increasing levels of woody debris lead to a decreasing probability of foraging by white rhino. I also demonstrate how the probability of foraging by mesoherbivores increases as the amount of forage increases. However, since this study took place during a severe drought where resources are extremely limited, I was unable to properly separate the effects of elephant-deposited woody debris from the severe lack of rainfall on grass response and subsequently herbivore foraging behaviour. Due possibly to the drought, mesoherbivores responded less or not at all to risk factors such as woody debris therefore woody debris was not a predictor of vigilance behaviour in my study. This study contributes to our understanding of how the impacts of elephants, as ecosystem engineers, have cascading effects on savanna ecosystems. My study showed that elephant impact mediates the foraging behaviour of white rhino during a drought. However, under average rainfall periods, my original hypothesized effect of the indirect impacts of elephants on white rhino foraging and grazing lawn dynamics could still hold. This key hypothesis that I was unable to test under ‘normal’ conditions due to the drought is still valid and functionally important for understanding the ecosystem processes driving grazing lawn formation, persistence and composition in African savannas where elephants and white rhinos coexist.
- Full Text:
- Date Issued: 2017
Perceptions of rural households about the role and effect of biogas production on rural household income in Raymond Mhlaba Local Municipality
- Authors: Ngcobo, Lindiwe
- Date: 2017
- Subjects: Biomass energy -- South Africa -- Eastern Cape Renewable energy sources -- South Africa -- Eastern Cape Sustainable living -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4694 , vital:28494
- Description: Rural development efforts to reduce poverty and enhance food security and generally improve livelihoods in developing countries continue to be constrained by high energy cost. For that reason, renewable energy has been identified as a possible panacea to fill this gap. Renewable energy is cheaper, more accessible and environmentally sustainable and promotes inclusivity. Biogas is a renewable energy that is readily available and easy to use by poor rural households. The use of biogas digesters among households in rural areas of developing countries is a well-known technology. The potential for biogas in these areas has been demonstrated and a strong economic case has been made. However, its adoption and use have been lower than expectations possibly as result of non-economic considerations, including social issues about which rural people hold different perceptions. Perceptions of rural households are important because they influence the behaviour to a large extent. Since limited access to affordable energy in rural areas has encouraged government and private organisations to initiate biogas projects to overcome the challenge, it is important to ascertain the factors that affect attitudes towards the technology. The present study sought to explore perceptions of rural households about biogas production towards rural household income in the Raymond Mhlaba Local Municipality. Specifically, this research investigated the state of biogas project being implemented by the University of Fort Hare’s Institute of Technology (FHIT), the perceptions of respondents towards biogas production and determine the contribution of biogas consumption to rural income. The study also aimed to identify the factors affecting the adoption of biogas production in the study area. The study was carried out in Melani village in Raymond Mhlaba Local Municipality in the Eastern Cape Province of South Africa and employed survey data obtained from 48 households who were enumerated to identify their perceptions on biogas production, with special emphasis on the role and effect contributed to rural income of Melani village. The study employed a cross-sectional research design and purposive sampling technique was used in data collection. Data were collected and captured in Excel and then analysed using the statistical package for social sciences (SPSS) Version 24 Descriptive statistics was used to examine socio-economic characteristics of households and state of biogas production in the area, Bivariate correlation analysis was used to determine the relationships among the key elements of perceptions of household towards biogas adoption, binary logistic model was used to estimate factors influencing adoption of biogas technology by households. The results show that women were dominant for both adopters and non-adopters of biogas. The majority of households were young with mean age of 40 years while for non-adopters were 65 years old on average. The results showed high levels of literacy amongst household adopters. Majority of the households for both adopters and non-adopters of biogas technology were married and unemployed and household size ranged from one to five persons, with social grants being dominant source of income. The bivariate correlation analysis suggests a positive effect of green pepper production and livestock ownership on biogas technology adoption. Age and level of education were negatively correlated with adoption of biogas. The cross tabulation analysis suggests that water scarcity, lack of knowledge about biogas technology, cattle ownership, lack of maintenance and repairing, flooded biogas digesters during rainy season are negatively associated with the uptake of biogas technology. The empirical results from binary logistic model suggest that land size was the key determinant of adoption behaviour towards biogas technology while age of the household head, source of income and level of education may have a negative influence on adoption of biogas technology. Based on the findings highlighted above, the study recommends strategies to encourage households to adopt biogas technology.
- Full Text:
- Date Issued: 2017
- Authors: Ngcobo, Lindiwe
- Date: 2017
- Subjects: Biomass energy -- South Africa -- Eastern Cape Renewable energy sources -- South Africa -- Eastern Cape Sustainable living -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4694 , vital:28494
- Description: Rural development efforts to reduce poverty and enhance food security and generally improve livelihoods in developing countries continue to be constrained by high energy cost. For that reason, renewable energy has been identified as a possible panacea to fill this gap. Renewable energy is cheaper, more accessible and environmentally sustainable and promotes inclusivity. Biogas is a renewable energy that is readily available and easy to use by poor rural households. The use of biogas digesters among households in rural areas of developing countries is a well-known technology. The potential for biogas in these areas has been demonstrated and a strong economic case has been made. However, its adoption and use have been lower than expectations possibly as result of non-economic considerations, including social issues about which rural people hold different perceptions. Perceptions of rural households are important because they influence the behaviour to a large extent. Since limited access to affordable energy in rural areas has encouraged government and private organisations to initiate biogas projects to overcome the challenge, it is important to ascertain the factors that affect attitudes towards the technology. The present study sought to explore perceptions of rural households about biogas production towards rural household income in the Raymond Mhlaba Local Municipality. Specifically, this research investigated the state of biogas project being implemented by the University of Fort Hare’s Institute of Technology (FHIT), the perceptions of respondents towards biogas production and determine the contribution of biogas consumption to rural income. The study also aimed to identify the factors affecting the adoption of biogas production in the study area. The study was carried out in Melani village in Raymond Mhlaba Local Municipality in the Eastern Cape Province of South Africa and employed survey data obtained from 48 households who were enumerated to identify their perceptions on biogas production, with special emphasis on the role and effect contributed to rural income of Melani village. The study employed a cross-sectional research design and purposive sampling technique was used in data collection. Data were collected and captured in Excel and then analysed using the statistical package for social sciences (SPSS) Version 24 Descriptive statistics was used to examine socio-economic characteristics of households and state of biogas production in the area, Bivariate correlation analysis was used to determine the relationships among the key elements of perceptions of household towards biogas adoption, binary logistic model was used to estimate factors influencing adoption of biogas technology by households. The results show that women were dominant for both adopters and non-adopters of biogas. The majority of households were young with mean age of 40 years while for non-adopters were 65 years old on average. The results showed high levels of literacy amongst household adopters. Majority of the households for both adopters and non-adopters of biogas technology were married and unemployed and household size ranged from one to five persons, with social grants being dominant source of income. The bivariate correlation analysis suggests a positive effect of green pepper production and livestock ownership on biogas technology adoption. Age and level of education were negatively correlated with adoption of biogas. The cross tabulation analysis suggests that water scarcity, lack of knowledge about biogas technology, cattle ownership, lack of maintenance and repairing, flooded biogas digesters during rainy season are negatively associated with the uptake of biogas technology. The empirical results from binary logistic model suggest that land size was the key determinant of adoption behaviour towards biogas technology while age of the household head, source of income and level of education may have a negative influence on adoption of biogas technology. Based on the findings highlighted above, the study recommends strategies to encourage households to adopt biogas technology.
- Full Text:
- Date Issued: 2017
Yield responses, mineral levels of forages and soil in old arable land planted to four legume pasture species in Lushington communal area, South Africa
- Authors: Gulwa, Unathi
- Date: 2017
- Subjects: Forage plants -- South Africa -- Eastern Cape Minerals in animal nutrition Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2799 , vital:28091
- Description: This study was conducted in the old arable land located in Lushington communal area in the Eastern Cape province of South Africa. The objectives of the study were to assess the effect of legume introduction on biomass yield, forage and soil mineral levels of the arable lands planted to four leguminous pastures in four seasons. Planting was done in March and October 2008 in Lushington. All legumes were subjected to grow under rain fed conditions. Trifolium vesiculosum (arrowleaf clover), Lespedeza cuneata (sericea lespedeza), Trifolium repens (white clover) and Lotus corniculatus (birdsfoot trefoil) are the four forage legume species that were sampled for the purposes of this study. The four legume species persisted out of the fourteen species that were initially tested for adaptability and persistence in the environmental conditions of Lushington communal area. The legumes, grasses and soils from these legume plots were sampled to determine the effect of legume introduction on the forage yield, mineral contents of the companion grasses and soils over four seasons. Plant and soil samples were collected once in spring (November) 2013, summer (February), autumn (March) and winter (May) 2014 for biomass production, macro and micronutrients determination. Results indicated that legume inclusion and season affected (P < 0.05) the total dry matter (TDM) yield production. Plots with Lespedeza cuneata had the highest TDM (1843 kg/ha) and control plots had the least dry matter production (1091 kg/ha). Summer season provided the highest (P < 0.05) TDM compared to the other seasons. Both legume and grass quality was also affected (P < 0.05) by legume inclusion in different seasons. Accordingly, grasses harvested from Trifolium repens plot showed higher CP level (10.90 percent) than those harvested from other plots whereas the lowest grass CP content (6.90 percent) was measured in the control treatment. L. cuneate had the highest (P < 0.05) CP level (11.00 percent) and T. repens had the least CP (6.63 percent) level. Grasses harvested in autumn had the highest (P < 0.05) CP level (12.50 percent) and those harvested in winter had the least CP level (4.60 percent). Similarly, all legume pastures harvested in spring had superior (P < 0.05) CP (10.80 percent) levels and those harvested in winter had the least CP (3.50 percent) level. Legume inclusion had an effect (P < 0.05) on both grass and legume macro nutrient contents. Trifolium repens plot had the highest grass K (1.07 percent), Ca (1.50 percent) and Mg (1.83 percent), whereas there were lower K (0.12 percent), Ca (1.25 percent) and Mg (1.08 percent) contents in grasses harvested from the control and T. vesiculosum plots, respectively. In legumes, macro nutrient concentrations: K (0.68 percent), Ca (1.75 percent) were superior in the T. vesiculosum plot in comparison to other plots. Season also affected (P < 0.05) both grass and legume macro nutrient content. There was higher K (0.90 percent), Ca (1.30 percent) and Mg (0.94 percent) content in grasses harvested in autumn whereas there were lower levels in winter harvests. In legumes, superior K (0.74 percent) and Mg (1.87 percent) content were attained during spring while the least were measured in winter (0.07 percent) and autumn (0.75 percent), respectively. Likewise, both legume inclusion and season had an significant effect (P < 0.05) on the forages micronutrient levels. During spring, there was superior soil P content (36.28 mg/kg) while during autumn; there was less P (22.58 mg/kg) content. The highest SOC level (1.49 percent) was measured in the T. repens plot whereas the lowest SOC (1.15 percent) was attained in the control plot. The results of this study showed that grass legume mixtures produced forages with high nutrient content and herbage yield. Legume planting in the old arable lands has a potential to improve soil quality parameters such as soil P and SOC content.
- Full Text:
- Date Issued: 2017
- Authors: Gulwa, Unathi
- Date: 2017
- Subjects: Forage plants -- South Africa -- Eastern Cape Minerals in animal nutrition Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2799 , vital:28091
- Description: This study was conducted in the old arable land located in Lushington communal area in the Eastern Cape province of South Africa. The objectives of the study were to assess the effect of legume introduction on biomass yield, forage and soil mineral levels of the arable lands planted to four leguminous pastures in four seasons. Planting was done in March and October 2008 in Lushington. All legumes were subjected to grow under rain fed conditions. Trifolium vesiculosum (arrowleaf clover), Lespedeza cuneata (sericea lespedeza), Trifolium repens (white clover) and Lotus corniculatus (birdsfoot trefoil) are the four forage legume species that were sampled for the purposes of this study. The four legume species persisted out of the fourteen species that were initially tested for adaptability and persistence in the environmental conditions of Lushington communal area. The legumes, grasses and soils from these legume plots were sampled to determine the effect of legume introduction on the forage yield, mineral contents of the companion grasses and soils over four seasons. Plant and soil samples were collected once in spring (November) 2013, summer (February), autumn (March) and winter (May) 2014 for biomass production, macro and micronutrients determination. Results indicated that legume inclusion and season affected (P < 0.05) the total dry matter (TDM) yield production. Plots with Lespedeza cuneata had the highest TDM (1843 kg/ha) and control plots had the least dry matter production (1091 kg/ha). Summer season provided the highest (P < 0.05) TDM compared to the other seasons. Both legume and grass quality was also affected (P < 0.05) by legume inclusion in different seasons. Accordingly, grasses harvested from Trifolium repens plot showed higher CP level (10.90 percent) than those harvested from other plots whereas the lowest grass CP content (6.90 percent) was measured in the control treatment. L. cuneate had the highest (P < 0.05) CP level (11.00 percent) and T. repens had the least CP (6.63 percent) level. Grasses harvested in autumn had the highest (P < 0.05) CP level (12.50 percent) and those harvested in winter had the least CP level (4.60 percent). Similarly, all legume pastures harvested in spring had superior (P < 0.05) CP (10.80 percent) levels and those harvested in winter had the least CP (3.50 percent) level. Legume inclusion had an effect (P < 0.05) on both grass and legume macro nutrient contents. Trifolium repens plot had the highest grass K (1.07 percent), Ca (1.50 percent) and Mg (1.83 percent), whereas there were lower K (0.12 percent), Ca (1.25 percent) and Mg (1.08 percent) contents in grasses harvested from the control and T. vesiculosum plots, respectively. In legumes, macro nutrient concentrations: K (0.68 percent), Ca (1.75 percent) were superior in the T. vesiculosum plot in comparison to other plots. Season also affected (P < 0.05) both grass and legume macro nutrient content. There was higher K (0.90 percent), Ca (1.30 percent) and Mg (0.94 percent) content in grasses harvested in autumn whereas there were lower levels in winter harvests. In legumes, superior K (0.74 percent) and Mg (1.87 percent) content were attained during spring while the least were measured in winter (0.07 percent) and autumn (0.75 percent), respectively. Likewise, both legume inclusion and season had an significant effect (P < 0.05) on the forages micronutrient levels. During spring, there was superior soil P content (36.28 mg/kg) while during autumn; there was less P (22.58 mg/kg) content. The highest SOC level (1.49 percent) was measured in the T. repens plot whereas the lowest SOC (1.15 percent) was attained in the control plot. The results of this study showed that grass legume mixtures produced forages with high nutrient content and herbage yield. Legume planting in the old arable lands has a potential to improve soil quality parameters such as soil P and SOC content.
- Full Text:
- Date Issued: 2017
A sedimentological and structural study of the lower Ecca Group, with a focus on facies analysis of the Collingham Formation, north of Grahamstown, SE Karoo Basin, South Africa
- Authors: Slamang, Shereen
- Date: 2017
- Subjects: Formations (Geology) -- South Africa -- Grahamstown Facies (Geology) -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/21099 , vital:29439
- Description: A study of the Collingham Formation was conducted in the area of the Ecca Pass and Committees Drift Road some 20km north of Grahamstown, Eastern Cape. The study incorporates outcrops of the lower Ecca Group, with a focus on the Collingham Formation. The structural and sedimentological characteristics have been documented, and a detailed description and facies outcrop characterization of the Collingham Formation has been undertaken. The combined thickness of the Prince Albert (~55m), Whitehill (~12m), and Collingham (~20m) Formations is approximately 85m. These formations are composed of fine grained parallel laminated mudrocks of mostly silt- and clay-size particles. A general north-easterly dip direction is recorded with three prominent joint directions striking NNE, NNW, and ESE. Intense small scale folding is evident in the Whitehill Formation, and is likely linked to local décollement structures; while north-verging duplex faults in the Prince Albert Formation is possibly linked to a sole thrust/detachment fault rooted in rocks of the Cape Supergroup. The foreland model has been proposed for these deformational structures. Six lithofacies have been recognised in the Collingham Formation, namely; claystone facies, mudstone facies, siltstone facies, chert facies, tuff facies, and shale facies. The Collingham Formation is comprised of an upward fining sequence of sediments; seen from the gradual change from siltstone facies in the lower layers, to mudstone facies, and claystone facies in the upper layers. This was created in a delta environment whereby clay particles were held in suspension in a hypopycnal mouth bar, and slowly settled to form claystone facies. An influx of sediment caused silt particles to settle further out to sea under the influence of gravity in a hyperpycnal mouth bar, thereby forming siltstone facies. Mudstone facies formed as the sediment supply gradually depleted, subsequently reducing the concentration of silt particles. The dominance of clay particles present suggests deposition to have occurred in tranquil waters, in a possible intracratonic basin setting, where the water depth is known to be a lot shallower. An upward decrease in organic content is seen by the colour change of mudrocks from dark grey near the base to dark green grey in the upper layers. Chlorite is commonly found in thin section, SEM, and XRD, and is an indication that the formation was later subject to low grade greenschist facies metamorphism.
- Full Text:
- Date Issued: 2017
- Authors: Slamang, Shereen
- Date: 2017
- Subjects: Formations (Geology) -- South Africa -- Grahamstown Facies (Geology) -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/21099 , vital:29439
- Description: A study of the Collingham Formation was conducted in the area of the Ecca Pass and Committees Drift Road some 20km north of Grahamstown, Eastern Cape. The study incorporates outcrops of the lower Ecca Group, with a focus on the Collingham Formation. The structural and sedimentological characteristics have been documented, and a detailed description and facies outcrop characterization of the Collingham Formation has been undertaken. The combined thickness of the Prince Albert (~55m), Whitehill (~12m), and Collingham (~20m) Formations is approximately 85m. These formations are composed of fine grained parallel laminated mudrocks of mostly silt- and clay-size particles. A general north-easterly dip direction is recorded with three prominent joint directions striking NNE, NNW, and ESE. Intense small scale folding is evident in the Whitehill Formation, and is likely linked to local décollement structures; while north-verging duplex faults in the Prince Albert Formation is possibly linked to a sole thrust/detachment fault rooted in rocks of the Cape Supergroup. The foreland model has been proposed for these deformational structures. Six lithofacies have been recognised in the Collingham Formation, namely; claystone facies, mudstone facies, siltstone facies, chert facies, tuff facies, and shale facies. The Collingham Formation is comprised of an upward fining sequence of sediments; seen from the gradual change from siltstone facies in the lower layers, to mudstone facies, and claystone facies in the upper layers. This was created in a delta environment whereby clay particles were held in suspension in a hypopycnal mouth bar, and slowly settled to form claystone facies. An influx of sediment caused silt particles to settle further out to sea under the influence of gravity in a hyperpycnal mouth bar, thereby forming siltstone facies. Mudstone facies formed as the sediment supply gradually depleted, subsequently reducing the concentration of silt particles. The dominance of clay particles present suggests deposition to have occurred in tranquil waters, in a possible intracratonic basin setting, where the water depth is known to be a lot shallower. An upward decrease in organic content is seen by the colour change of mudrocks from dark grey near the base to dark green grey in the upper layers. Chlorite is commonly found in thin section, SEM, and XRD, and is an indication that the formation was later subject to low grade greenschist facies metamorphism.
- Full Text:
- Date Issued: 2017
Stochastic models in finance
- Authors: Mazengera, Hassan
- Date: 2017
- Subjects: Finance -- Mathematical models , C++ (Computer program language) , GARCH model , Lebesgue-Radon-Nikodym theorems , Radon measures , Stochastic models , Stochastic processes , Stochastic processes -- Computer programs , Martingales (Mathematics) , Pricing -- Mathematical models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/162724 , vital:40976
- Description: Stochastic models for pricing financial securities are developed. First, we consider the Black Scholes model, which is a classic example of a complete market model and finally focus on Lévy driven models. Jumps may render the market incomplete and are induced in a model by inclusion of a Poisson process. Lévy driven models are more realistic in modelling of asset price dynamics than the Black Scholes model. Martingales are central in pricing, especially of derivatives and we give them the desired attention in the context of pricing. There are an increasing number of important pricing models where analytical solutions are not available hence computational methods come in handy, see Broadie and Glasserman (1997). It is also important to note that computational methods are also applicable to models with analytical solutions. We computationally value selected stochastic financial models using C++. Computational methods are also used to value or price complex financial instruments such as path dependent derivatives. This pricing procedure is applied in the computational valuation of a stochastic (revenue based) loan contract. Derivatives with simple pay of functions and models with analytical solutions are considered for illustrative purposes. The Black-Scholes P.D.E is complex to solve analytically and finite difference methods are widely used. Explicit finite difference scheme is considered in this thesis for computational valuation of derivatives that are modelled by the Black-Scholes P.D.E. Stochastic modelling of asset prices is important for the valuation of derivatives: Gaussian, exponential and gamma variates are simulated for the valuation purposes.
- Full Text:
- Date Issued: 2017
- Authors: Mazengera, Hassan
- Date: 2017
- Subjects: Finance -- Mathematical models , C++ (Computer program language) , GARCH model , Lebesgue-Radon-Nikodym theorems , Radon measures , Stochastic models , Stochastic processes , Stochastic processes -- Computer programs , Martingales (Mathematics) , Pricing -- Mathematical models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/162724 , vital:40976
- Description: Stochastic models for pricing financial securities are developed. First, we consider the Black Scholes model, which is a classic example of a complete market model and finally focus on Lévy driven models. Jumps may render the market incomplete and are induced in a model by inclusion of a Poisson process. Lévy driven models are more realistic in modelling of asset price dynamics than the Black Scholes model. Martingales are central in pricing, especially of derivatives and we give them the desired attention in the context of pricing. There are an increasing number of important pricing models where analytical solutions are not available hence computational methods come in handy, see Broadie and Glasserman (1997). It is also important to note that computational methods are also applicable to models with analytical solutions. We computationally value selected stochastic financial models using C++. Computational methods are also used to value or price complex financial instruments such as path dependent derivatives. This pricing procedure is applied in the computational valuation of a stochastic (revenue based) loan contract. Derivatives with simple pay of functions and models with analytical solutions are considered for illustrative purposes. The Black-Scholes P.D.E is complex to solve analytically and finite difference methods are widely used. Explicit finite difference scheme is considered in this thesis for computational valuation of derivatives that are modelled by the Black-Scholes P.D.E. Stochastic modelling of asset prices is important for the valuation of derivatives: Gaussian, exponential and gamma variates are simulated for the valuation purposes.
- Full Text:
- Date Issued: 2017
Evaluation of groundwater potential using neotectonics and geophysics in the context of post Karoo tectonic framework around Fort Beaufort and Smithfield, Eastern Cape, South Africa
- Authors: Ndlovu, Nkosilathi
- Date: 2017
- Subjects: Neotectonics -- South Africa -- Eastern Cape Groundwater -- South Africa -- Eastern Cape Geophysical surveys -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12687 , vital:39299
- Description: Geological and geophysical methods were used to investigate the Karoo area extending from longitudes 25.50 E to 27.50 E and latitudes 300 S to 330 S in South Africa, particularly Fort Beaufort, Aliwal North, Venterstad and Smithfield. The geology of the area is dominated by the upper Beaufort Group (Adelaide Subgroup) with an extensive network of dolerite sills and dykes that intruded the sedimentary sequence. A relationship between neotectonics, post-Karoo tectonics, groundwater and lithology was investigated to locate suitable groundwater potential sites. Apart from studying the role of neotectonics and the post Karoo tectonics, this research aims at generating groundwater targets to alleviate water shortages mainly for farming and livestock, and prove that neotectonics is still active. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, geophysical investigation (magnetic, gravity, and vertical electrical sounding), and the application of Geographical Information Systems (GIS) and remote sensing. Twenty samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and have variable mineralogy (presence of heavy minerals) within the rocks. The use of Geographical Information Systems (GIS) and remote sensing in geological surveys, especially hydrogeology, has gained momentum over the past few years. This research is no exception as ArcMap software was used to create a map of seismic epicentres of the Eastern Cape Province. From the map it can be observed that seismicity still occurs and thus leading to the notion of neotectonics being active. Lineaments were also automatically extracted using the ENVI 5.1 and Geomatica 2013 software. Lineaments are zones of weakness in the subsurface of the Earth and are very important in locating groundwater potential sites. Geophysical techniques are essential and highly accurate for groundwater studies. Gravity and magnetic techniques were applied on data which was supplied as grids. Analysis using Geosoft Oasis 8.3 revealed extensive lineaments and ring like patterns and these were inferred to be dolerite intrusions (sills and dykes). The morphology of the intrusions help in identifying possible groundwater potential zones and thus they should be investigated. Vertical electrical sounding (VES) technique using the Schlumberger array was carried out at three sites (Fort Beaufort fracture which is possibly related to Quaternary surface uplift of the Amatole-Swaziland axis, splay of the Fort Beaufort fracture and at a site which showed high groundwater potential) to explore subsurface layering. IP2win (lite), 1-D modelling software was used to model the apparent resistivity data to obtain the geoelectric parameters of the subsurface (thickness and resistivity). The VES results are consistent with fractured rocks that aid groundwater movement. The VES data for the three sites was further modelled by the RES2DINV software and this shows low resistivity values associated with loose, water saturated top sandy soil and higher resistivity values associated with sedimentary sequences and dolerite. Moreover, potential sites for citing wells are predicted to be between 79.5 and 128 m on the profile. Further neotectonic studies need to be done, especially on the quaternary sediments as they would have more neotectonic evidence. The use of geophysical techniques for groundwater search need to be intensified, with more emphasis being put to the sedimentary sequences bordered by dolerite intrusions and fractured zones.
- Full Text:
- Date Issued: 2017
- Authors: Ndlovu, Nkosilathi
- Date: 2017
- Subjects: Neotectonics -- South Africa -- Eastern Cape Groundwater -- South Africa -- Eastern Cape Geophysical surveys -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12687 , vital:39299
- Description: Geological and geophysical methods were used to investigate the Karoo area extending from longitudes 25.50 E to 27.50 E and latitudes 300 S to 330 S in South Africa, particularly Fort Beaufort, Aliwal North, Venterstad and Smithfield. The geology of the area is dominated by the upper Beaufort Group (Adelaide Subgroup) with an extensive network of dolerite sills and dykes that intruded the sedimentary sequence. A relationship between neotectonics, post-Karoo tectonics, groundwater and lithology was investigated to locate suitable groundwater potential sites. Apart from studying the role of neotectonics and the post Karoo tectonics, this research aims at generating groundwater targets to alleviate water shortages mainly for farming and livestock, and prove that neotectonics is still active. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, geophysical investigation (magnetic, gravity, and vertical electrical sounding), and the application of Geographical Information Systems (GIS) and remote sensing. Twenty samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and have variable mineralogy (presence of heavy minerals) within the rocks. The use of Geographical Information Systems (GIS) and remote sensing in geological surveys, especially hydrogeology, has gained momentum over the past few years. This research is no exception as ArcMap software was used to create a map of seismic epicentres of the Eastern Cape Province. From the map it can be observed that seismicity still occurs and thus leading to the notion of neotectonics being active. Lineaments were also automatically extracted using the ENVI 5.1 and Geomatica 2013 software. Lineaments are zones of weakness in the subsurface of the Earth and are very important in locating groundwater potential sites. Geophysical techniques are essential and highly accurate for groundwater studies. Gravity and magnetic techniques were applied on data which was supplied as grids. Analysis using Geosoft Oasis 8.3 revealed extensive lineaments and ring like patterns and these were inferred to be dolerite intrusions (sills and dykes). The morphology of the intrusions help in identifying possible groundwater potential zones and thus they should be investigated. Vertical electrical sounding (VES) technique using the Schlumberger array was carried out at three sites (Fort Beaufort fracture which is possibly related to Quaternary surface uplift of the Amatole-Swaziland axis, splay of the Fort Beaufort fracture and at a site which showed high groundwater potential) to explore subsurface layering. IP2win (lite), 1-D modelling software was used to model the apparent resistivity data to obtain the geoelectric parameters of the subsurface (thickness and resistivity). The VES results are consistent with fractured rocks that aid groundwater movement. The VES data for the three sites was further modelled by the RES2DINV software and this shows low resistivity values associated with loose, water saturated top sandy soil and higher resistivity values associated with sedimentary sequences and dolerite. Moreover, potential sites for citing wells are predicted to be between 79.5 and 128 m on the profile. Further neotectonic studies need to be done, especially on the quaternary sediments as they would have more neotectonic evidence. The use of geophysical techniques for groundwater search need to be intensified, with more emphasis being put to the sedimentary sequences bordered by dolerite intrusions and fractured zones.
- Full Text:
- Date Issued: 2017
Using computer vision to categorize tyres and estimate the number of visible tyres in tyre stockpile images
- Authors: Eastwood, Grant
- Date: 2017
- Subjects: Tires -- Specifications Tires -- Recycling , Tires -- Maintenance and repair
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/16022 , vital:28313
- Description: Pressures from environmental agencies contribute to the challenges associated with the disposal of waste tyres, particularly in South Africa. Recycling of waste tyres in South Africa is in its infancy resulting in the historically undocumented and uncontrolled existence of waste tyre stockpiles across the country. The remote and distant locations of such stockpiles typically complicate the logistics associated with the collection, transport and storage of waste tyres prior to entering the recycling process. In order to optimize the logistics associated with the collection of waste tyres from stockpiles, useful information about such stockpiles would include estimates of the types of tyres as well as the quantity of specific tyre types found in particular stockpiles. This research proposes the use of computer vision for categorizing individual tyres and estimating the number of visible tyres in tyre stockpile images to support the logistics in tyre recycling efforts. The study begins with a broad review of image processing and computer vision algorithms for categorization and counting objects in images. The bag of visual words (BoVW) model for categorization is tested on two small data sets of tread tyre images using a random sub-sampling holdout method. The categorization results are evaluated using performance metrics for multiclass classifiers, namely the average accuracy, precision, and recall. The results indicated that corner-based local feature detectors combined with speeded up robust features (SURF) descriptors in a BoVW model provide moderately accurate categorization of tyres based on tread images. Two feature extraction methods for extracting features for use in training neural networks (NNs) for tyre count estimations in tyre stockpiles are proposed. The two feature extraction methods are used to describe images in terms of feature vectors that can be used as input for NNs. The first feature extraction method uses the BoVW model with histograms of oriented gradients (HOG) features collected from overlapping sub-images to create a visual vocabulary and describe the images in terms of their visual word occurrence histogram. The second feature extraction method uses the image gradient magnitude, gradient orientation, and edge orientations of edges detected using the Canny edge detector. A concatenated histogram is constructed from individual histograms of gradient orientations and gradient magnitude. The histograms are then used to train NNs using backpropogation to approximate functions from the feature vectors describing the images to scalar count estimations. The accuracy of visible object count predictions are evaluated using NN evaluation techniques to determine the accuracy of predictions and the generalization ability of the fit model. The count estimation experiments using the two feature extraction methods for input to NNs showed that fairly accurate count estimations can be obtained and that the fit model could generalize fairly well to unseen images.
- Full Text:
- Date Issued: 2017
- Authors: Eastwood, Grant
- Date: 2017
- Subjects: Tires -- Specifications Tires -- Recycling , Tires -- Maintenance and repair
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/16022 , vital:28313
- Description: Pressures from environmental agencies contribute to the challenges associated with the disposal of waste tyres, particularly in South Africa. Recycling of waste tyres in South Africa is in its infancy resulting in the historically undocumented and uncontrolled existence of waste tyre stockpiles across the country. The remote and distant locations of such stockpiles typically complicate the logistics associated with the collection, transport and storage of waste tyres prior to entering the recycling process. In order to optimize the logistics associated with the collection of waste tyres from stockpiles, useful information about such stockpiles would include estimates of the types of tyres as well as the quantity of specific tyre types found in particular stockpiles. This research proposes the use of computer vision for categorizing individual tyres and estimating the number of visible tyres in tyre stockpile images to support the logistics in tyre recycling efforts. The study begins with a broad review of image processing and computer vision algorithms for categorization and counting objects in images. The bag of visual words (BoVW) model for categorization is tested on two small data sets of tread tyre images using a random sub-sampling holdout method. The categorization results are evaluated using performance metrics for multiclass classifiers, namely the average accuracy, precision, and recall. The results indicated that corner-based local feature detectors combined with speeded up robust features (SURF) descriptors in a BoVW model provide moderately accurate categorization of tyres based on tread images. Two feature extraction methods for extracting features for use in training neural networks (NNs) for tyre count estimations in tyre stockpiles are proposed. The two feature extraction methods are used to describe images in terms of feature vectors that can be used as input for NNs. The first feature extraction method uses the BoVW model with histograms of oriented gradients (HOG) features collected from overlapping sub-images to create a visual vocabulary and describe the images in terms of their visual word occurrence histogram. The second feature extraction method uses the image gradient magnitude, gradient orientation, and edge orientations of edges detected using the Canny edge detector. A concatenated histogram is constructed from individual histograms of gradient orientations and gradient magnitude. The histograms are then used to train NNs using backpropogation to approximate functions from the feature vectors describing the images to scalar count estimations. The accuracy of visible object count predictions are evaluated using NN evaluation techniques to determine the accuracy of predictions and the generalization ability of the fit model. The count estimation experiments using the two feature extraction methods for input to NNs showed that fairly accurate count estimations can be obtained and that the fit model could generalize fairly well to unseen images.
- Full Text:
- Date Issued: 2017
Chemical composition of leaf essential oils of Lantana camara varieties in South Africa and their effect on the behavioural preference of Falconia intermedia
- Authors: Ngxande-Koza, Samella W
- Date: 2017
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4877 , vital:20739
- Description: Lantana camara L. (Verbenaceae) is one the most problematic invaders in South Africa invading forest edges, sand dunes, and shorelines by forming impenetrable thickets. Lantana camara invasions degrade natural biodiversity, reduce the value of land and consequently it has been a target for biological control, over the last 50 years in South Africa. Studies that have reported on chemical profile of Lantana camara have been conducted around the world but not in South Africa. Hence, the first aim of the current study was to identify the chemical baseline of L. camara varieties in the Eastern Cape, South Africa. Recent studies have shown that feeding by one of the agents released against L. camara, Falconia intermedia (Distant) (Hemiptera: Miridae), induces anti-herbivory response through increased leaf toughness and trichome density. A preliminary study conducted also reported the production of volatile chemicals by one variety, Whitney Farm, due to feeding by the mirids. Therefore, the second aim was to determine the induced changes in chemical compounds of L. camara varieties after feeding by F. intermedia. A third aim was to determine the effect these chemical compounds have on the behaviour of F. intermedia. To identify the chemical baseline of L. camara varieties, the essential oils of four L. camara varieties (East London, Port Alfred, Whitney Farm and Heather Glen) were analysed using gas chromatography mass spectrometry (GC-MS) and that resulted to the identification of 163 constitutive and 75 induced chemicals across the varieties tested. Lantana camara varieties showed different chemical classes but were highly dominated by terpenes. A great variation in the number of constitutive chemical compounds was found in all the varieties. There were 56 constitutive chemical compounds in the Whitney Farm variety, 41 in the East London variety, 36 in the Heather Glen variety and 30 in the Port Alfred variety. The Whitney Farm variety had the highest number (22) of unique constitutive chemicals identified when compared with other varieties. This indicates the chemical distinctiveness of the Whitney Farm variety from the other varieties. In the varieties tested, there were common chemical compounds identified in constitutive and induced (discussed below) states of the plants such as caryophyllene, hexane, naphthalene, copaene and a-caryophyllene. Besides naphthalene, the majority of chemical compounds in South African L. camara varieties were similar to compounds that have been identified across the world, suggesting that they are closely related. The expression of naphthalene in these varieties may be due to changes in the chemicals expressed over evolutionary time as predicted by the Novel Weapons Hypothesis. Amongst the varieties, a great variation in chemical compounds and their concentrations was shown in the induced states of the plants. The concentration of constitutive caryophyllene ranged from (3.13 - 15.7) %, to (4.02 - 11.10) % after feeding. The concentration of constitutive hexane ranged from (6.13 - 71.19) %, to (33.3 - 75.8) % after feeding. The concentration of constitutive naphthalene ranged from (0.21 - 4.79) %, to (0.92 - 2.11) % after feeding. The concentration of constitutive copaene ranged from (0.57 - 1.57) %, to (1.20 - 2.72) %. Lastly, the concentration of constitutive a-caryophyllene ranged from (1.18 - 9.03) %, to (0.78 - 5.48) % after feeding. The changes in chemical concentrations in lantana varieties indicated that feeding by the mirid on L. camara varieties causes an induction by either reducing or increasing the chemical concentrations. To determine the effect of the identified compounds on the behaviour of F. intermedia adults, olfactometer bioassays were conducted using a Y-tube technique. A significantly higher proportion of F. intermedia were attracted to undamaged leaves over damaged leaves and purified air. Undamaged leaves attracted 52 % of F. intermedia from the East London variety, 62.5 % from the Port Alfred variety, 56 % from the Whitney Farm variety, 58 % from the Lyndhurst variety and 54.5 % from the Heather Glen variety in dual choice trials versus damaged leaves. Furthermore, a significantly higher proportion of F. intermedia were attracted to damaged leaves over purified air. Damaged leaves attracted 67 % of F. intermedia from the East London variety, 67 % from the Port Alfred variety, 65.9 % from the Whitney Farm variety, 65.3 % from the Heather Glen variety and 64.5 % from the Lyndhurst variety. Olfactometer bioassays were also conducted using purified standard compounds of four chemical compounds identified from essential oils, hexane was used as a positive control as it is reported to be an insect attractant in literature. Hexane was highly attractive to the mirids compared to three standard compounds caryophyllene, caryophyllene oxide and naphthalene at the rate of 80 %, 73 % and 80 %, respectively. The standard compounds tested against F. intermedia are major compounds contained by L. camara varieties and they have proven to have a repellent effect. This may indicate that after feeding by F. intermedia, the major compounds expressed by the plant varieties repel F. intermedia contributing to the invasiveness of this weed. The increased expression of hexane and caryophyllene after feeding may also indicate increased attraction to some insects, opening up the potential for third trophic level interactions in varieties where this is the case. This is the first study on the chemical composition of essential oils of L. camara in South Africa. Therefore, we recommend that where appropriate chemical profile studies of the invasive alien plants should be considered during host specificity testing, and the vital role of chemical compounds on agent-weed interactions must be taken into consideration with other factors before and after the biological control agents are released.
- Full Text:
- Date Issued: 2017
- Authors: Ngxande-Koza, Samella W
- Date: 2017
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4877 , vital:20739
- Description: Lantana camara L. (Verbenaceae) is one the most problematic invaders in South Africa invading forest edges, sand dunes, and shorelines by forming impenetrable thickets. Lantana camara invasions degrade natural biodiversity, reduce the value of land and consequently it has been a target for biological control, over the last 50 years in South Africa. Studies that have reported on chemical profile of Lantana camara have been conducted around the world but not in South Africa. Hence, the first aim of the current study was to identify the chemical baseline of L. camara varieties in the Eastern Cape, South Africa. Recent studies have shown that feeding by one of the agents released against L. camara, Falconia intermedia (Distant) (Hemiptera: Miridae), induces anti-herbivory response through increased leaf toughness and trichome density. A preliminary study conducted also reported the production of volatile chemicals by one variety, Whitney Farm, due to feeding by the mirids. Therefore, the second aim was to determine the induced changes in chemical compounds of L. camara varieties after feeding by F. intermedia. A third aim was to determine the effect these chemical compounds have on the behaviour of F. intermedia. To identify the chemical baseline of L. camara varieties, the essential oils of four L. camara varieties (East London, Port Alfred, Whitney Farm and Heather Glen) were analysed using gas chromatography mass spectrometry (GC-MS) and that resulted to the identification of 163 constitutive and 75 induced chemicals across the varieties tested. Lantana camara varieties showed different chemical classes but were highly dominated by terpenes. A great variation in the number of constitutive chemical compounds was found in all the varieties. There were 56 constitutive chemical compounds in the Whitney Farm variety, 41 in the East London variety, 36 in the Heather Glen variety and 30 in the Port Alfred variety. The Whitney Farm variety had the highest number (22) of unique constitutive chemicals identified when compared with other varieties. This indicates the chemical distinctiveness of the Whitney Farm variety from the other varieties. In the varieties tested, there were common chemical compounds identified in constitutive and induced (discussed below) states of the plants such as caryophyllene, hexane, naphthalene, copaene and a-caryophyllene. Besides naphthalene, the majority of chemical compounds in South African L. camara varieties were similar to compounds that have been identified across the world, suggesting that they are closely related. The expression of naphthalene in these varieties may be due to changes in the chemicals expressed over evolutionary time as predicted by the Novel Weapons Hypothesis. Amongst the varieties, a great variation in chemical compounds and their concentrations was shown in the induced states of the plants. The concentration of constitutive caryophyllene ranged from (3.13 - 15.7) %, to (4.02 - 11.10) % after feeding. The concentration of constitutive hexane ranged from (6.13 - 71.19) %, to (33.3 - 75.8) % after feeding. The concentration of constitutive naphthalene ranged from (0.21 - 4.79) %, to (0.92 - 2.11) % after feeding. The concentration of constitutive copaene ranged from (0.57 - 1.57) %, to (1.20 - 2.72) %. Lastly, the concentration of constitutive a-caryophyllene ranged from (1.18 - 9.03) %, to (0.78 - 5.48) % after feeding. The changes in chemical concentrations in lantana varieties indicated that feeding by the mirid on L. camara varieties causes an induction by either reducing or increasing the chemical concentrations. To determine the effect of the identified compounds on the behaviour of F. intermedia adults, olfactometer bioassays were conducted using a Y-tube technique. A significantly higher proportion of F. intermedia were attracted to undamaged leaves over damaged leaves and purified air. Undamaged leaves attracted 52 % of F. intermedia from the East London variety, 62.5 % from the Port Alfred variety, 56 % from the Whitney Farm variety, 58 % from the Lyndhurst variety and 54.5 % from the Heather Glen variety in dual choice trials versus damaged leaves. Furthermore, a significantly higher proportion of F. intermedia were attracted to damaged leaves over purified air. Damaged leaves attracted 67 % of F. intermedia from the East London variety, 67 % from the Port Alfred variety, 65.9 % from the Whitney Farm variety, 65.3 % from the Heather Glen variety and 64.5 % from the Lyndhurst variety. Olfactometer bioassays were also conducted using purified standard compounds of four chemical compounds identified from essential oils, hexane was used as a positive control as it is reported to be an insect attractant in literature. Hexane was highly attractive to the mirids compared to three standard compounds caryophyllene, caryophyllene oxide and naphthalene at the rate of 80 %, 73 % and 80 %, respectively. The standard compounds tested against F. intermedia are major compounds contained by L. camara varieties and they have proven to have a repellent effect. This may indicate that after feeding by F. intermedia, the major compounds expressed by the plant varieties repel F. intermedia contributing to the invasiveness of this weed. The increased expression of hexane and caryophyllene after feeding may also indicate increased attraction to some insects, opening up the potential for third trophic level interactions in varieties where this is the case. This is the first study on the chemical composition of essential oils of L. camara in South Africa. Therefore, we recommend that where appropriate chemical profile studies of the invasive alien plants should be considered during host specificity testing, and the vital role of chemical compounds on agent-weed interactions must be taken into consideration with other factors before and after the biological control agents are released.
- Full Text:
- Date Issued: 2017
An analysis of flood activity over the past century based on the sedimentary deposits in the Mfolozi floodplain
- Authors: Mbao, Chabala
- Date: 2017
- Subjects: Floodplain morphology -- South Africa -- Mfolozi River , Floodplains -- South Africa -- Kwazulu-Natal , Sedimentation and deposition -- South Africa -- Kwazulu-Natal , Floods -- South Africa -- Kwazulu-Natal -- Measurement , Hydrology -- Research -- South Africa -- Kwazulu-Natal , Stream measurements -- South Africa -- Kwazulu-Natal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/53711 , vital:26312
- Description: Floods are natural phenomena that are of widespread interest to the scientific community, particularly in the context of understanding the impact of climate change as well as changing land use patterns and the security of infrastructure such as towns and roads. In northern KwaZulu-Natal, large flood events have been a reoccurring feature over the past century. The geographical position and extent of the region means that is affected by both inland and coastal weather phenomena, each with the potential to cause large flood events. While information pertaining to large floods in the region in the form of flow data is readily available, flow data is often incomplete and limited in terms of how far back in time the records extend. The Mfolozi River floodplain itself also houses a record of flood activity in the region in the form of sedimentary deposits, which have the potential to reveal flood activity over a much longer timescale, even when monitoring of flood activity in the region was not present. Establishing a link between the hydrological and sedimentary features of floods may be useful in establishing a record of flood activity extending beyond the limits of historical records. The aim of this project was to construct a record of major flood events on the Mfolozi River floodplain over the last century and determine their source. The first objective involved establishing the history of flood events in the Mfolozi River catchment utilising hydrological data recorded throughout the catchment. Thirty nine different large floods (defined as being over 800 m3.s-1) were recorded on the floodplain over the past century. The data also highlighted differences in the extent of known coastal and inland systems (tropical cyclones and cut-off lows respectively), allowing for inferences to be made about the area of the catchment most likely affected by each event; some flood events were identified as having mostly affected the upper reaches of the catchment, while others mostly affected the lower reaches, closer to the coast. The second objective was to identify the various physical, mineralogical and geochemical features of the sediment deposited on the Mfolozi floodplain. Multiple individual flood deposits were identified in the sedimentary record, with sediment tracing analysis providing insight into the source of the deposits within the catchment; no traces of igneous or metamorphic material could be found within the sediment. The source rocks were identified as mostly quartzite, with minor shale and sandstone deposits as well. This put the source of the sediment in the upper to middle reaches of the catchment. The sedimentary analysis was combined with the hydrological records to establish a chronology of flood events extending back to the 1960's. Unfortunately, this record could not be extended further due to the limited amount of sediment collected as well the limits of readily available analytical techniques; radionuclide dating methods were unsuccessful due to the low amounts of fallout radionuclides present in the sediment. The study has however successfully established a history of flood events in the region, as well as providing a link between the hydrological and sedimentary features of flood events that could potentially be useful for current and future research.
- Full Text:
- Date Issued: 2017
- Authors: Mbao, Chabala
- Date: 2017
- Subjects: Floodplain morphology -- South Africa -- Mfolozi River , Floodplains -- South Africa -- Kwazulu-Natal , Sedimentation and deposition -- South Africa -- Kwazulu-Natal , Floods -- South Africa -- Kwazulu-Natal -- Measurement , Hydrology -- Research -- South Africa -- Kwazulu-Natal , Stream measurements -- South Africa -- Kwazulu-Natal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/53711 , vital:26312
- Description: Floods are natural phenomena that are of widespread interest to the scientific community, particularly in the context of understanding the impact of climate change as well as changing land use patterns and the security of infrastructure such as towns and roads. In northern KwaZulu-Natal, large flood events have been a reoccurring feature over the past century. The geographical position and extent of the region means that is affected by both inland and coastal weather phenomena, each with the potential to cause large flood events. While information pertaining to large floods in the region in the form of flow data is readily available, flow data is often incomplete and limited in terms of how far back in time the records extend. The Mfolozi River floodplain itself also houses a record of flood activity in the region in the form of sedimentary deposits, which have the potential to reveal flood activity over a much longer timescale, even when monitoring of flood activity in the region was not present. Establishing a link between the hydrological and sedimentary features of floods may be useful in establishing a record of flood activity extending beyond the limits of historical records. The aim of this project was to construct a record of major flood events on the Mfolozi River floodplain over the last century and determine their source. The first objective involved establishing the history of flood events in the Mfolozi River catchment utilising hydrological data recorded throughout the catchment. Thirty nine different large floods (defined as being over 800 m3.s-1) were recorded on the floodplain over the past century. The data also highlighted differences in the extent of known coastal and inland systems (tropical cyclones and cut-off lows respectively), allowing for inferences to be made about the area of the catchment most likely affected by each event; some flood events were identified as having mostly affected the upper reaches of the catchment, while others mostly affected the lower reaches, closer to the coast. The second objective was to identify the various physical, mineralogical and geochemical features of the sediment deposited on the Mfolozi floodplain. Multiple individual flood deposits were identified in the sedimentary record, with sediment tracing analysis providing insight into the source of the deposits within the catchment; no traces of igneous or metamorphic material could be found within the sediment. The source rocks were identified as mostly quartzite, with minor shale and sandstone deposits as well. This put the source of the sediment in the upper to middle reaches of the catchment. The sedimentary analysis was combined with the hydrological records to establish a chronology of flood events extending back to the 1960's. Unfortunately, this record could not be extended further due to the limited amount of sediment collected as well the limits of readily available analytical techniques; radionuclide dating methods were unsuccessful due to the low amounts of fallout radionuclides present in the sediment. The study has however successfully established a history of flood events in the region, as well as providing a link between the hydrological and sedimentary features of flood events that could potentially be useful for current and future research.
- Full Text:
- Date Issued: 2017
Browsing as a demographic bottleneck in a semi-arid savanna: the effect of size and age on compensatory responses of Vachellia karroo seedlings after simulated herbivory
- Authors: Perumal, Lavinia
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4899 , vital:20741
- Description: Savannas are characterised by a continuous grass layer with scattered trees at varying densities. This vegetation structure is determined by several interacting factors, including fire, herbivory, resource competition and atmospheric CO2 concentration. The preservation of savanna biomes is important and a shift towards a woody biome threatens savanna globally. Bush encroachment which describes the shift towards domination of savannas by C3 woody plants, is especially acute in southern Africa. In semi-arid rangelands, encroachment progresses to dense thickets dominated by thorny and unpalatable bushes and trees. There is evidence that bush encroachment is driven by a reduction in fire and browsing events as well as their interaction. Despite browsing having strong effects on African savannas its isolated role in maintaining tree-grass coexistence has not received as much attention as the role of fire. Therefore the overall aim of this study was to examine the effects of browsing on seedlings of a commonly encroaching species, Vachellia karroo. Browsing was hypothesized to be a demographic release bottleneck for bush encroachment in a semiarid (MAP ~550mm) savanna in the Eastern Cape of South Africa, where fire has been historically rare. In a single study I explored the fate of V. karroo seedlings (less than a year old) following browsing in sub canopy and inter canopy microhabitats. Additionally, I explored how the fate of a seedling changed under high and low tree cover. Firstly, I investigated the type, intensity and frequency of herbivory, from both small and large herbivores, which seedlings were subjected to. Results revealed that browsing was severe and frequent with the majority of seedlings browsed more than twice over a 12 month period. Large browsers such as kudu and impala caused high seedling mortality (46%) while smaller browsers such as invertebrates were more effective at suppressing growth. Microhabitat had little impact on seedling survival, but significantly influenced plant compensatory growth. Reduced seedling growth following browsing was observed in the sub-canopy in comparison to seedling growth in full sunlight in the intercanopy, suggesting V.karroo may be shade intolerant. Secondly, the effect of tree cover on browsed seedlings was determined by quantifying browsing frequency and intensity at high and low tree cover. No differences in browsing intensity and frequency were observed between high and low tree cover. However, high tree cover due to bush encroachment limited seedling above ground growth. The aim of the second study was to investigate how V.karroo survival and growth were influenced by its age and size following simulated browsing. I explored this aim through field and greenhouse experiments. I was particularly interested in testing how plant sensitivity to varying defoliation intensities of repeated browsing varied with plant age (known ages of 6, 12, 16 and 30 weeks). There were large differences in mortality between the different age groups. Furthermore, age interacted with repeated browsing and negatively influenced seedling survival and regrowth. Older seedlings (16 and 30 week old) had greater survival and higher browsing frequencies resulted in greater mortality and reduced growth. The threshold age after which seedlings become more tolerant to herbivory occurs at an age of 28 weeks. Seedlings less than six weeks old experiencing intense (100 % defoliation)browsing had a very low probability (33%) of survival following just a single defoliation. Interestingly, all 16 week old seedlings regrew most of their foliage following a moderate (50%) defoliation with some plants overcompensating for leaf loss. The field study revealed two distinct demographic stages based on age and size (seedlings< 9 mm and saplings >9 mm in stem basal diameter (SBD)). Browsing had a strong negative effect on seedlings, resulting in reduced investment in leaf biomass. These findings suggest plant size and age can be used as robust predictors of a plants vulnerability to browsing. An increase in tree cover requires successful transitions of seedlings to saplings (also known as release). The results of this study suggest that in semi-arid savannas, browsing can impact tree cover through imposing a release bottleneck for tree seedlings and to lesser extent saplings. By limiting tree growth plants are kept in a disturbance trap and will therefore be exposed to not only browsers but fire. These findings also have important implications for tree-grass coexistence dynamics, suggesting that specific size and browsing thresholds should be considered in savanna management.
- Full Text:
- Date Issued: 2017
- Authors: Perumal, Lavinia
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4899 , vital:20741
- Description: Savannas are characterised by a continuous grass layer with scattered trees at varying densities. This vegetation structure is determined by several interacting factors, including fire, herbivory, resource competition and atmospheric CO2 concentration. The preservation of savanna biomes is important and a shift towards a woody biome threatens savanna globally. Bush encroachment which describes the shift towards domination of savannas by C3 woody plants, is especially acute in southern Africa. In semi-arid rangelands, encroachment progresses to dense thickets dominated by thorny and unpalatable bushes and trees. There is evidence that bush encroachment is driven by a reduction in fire and browsing events as well as their interaction. Despite browsing having strong effects on African savannas its isolated role in maintaining tree-grass coexistence has not received as much attention as the role of fire. Therefore the overall aim of this study was to examine the effects of browsing on seedlings of a commonly encroaching species, Vachellia karroo. Browsing was hypothesized to be a demographic release bottleneck for bush encroachment in a semiarid (MAP ~550mm) savanna in the Eastern Cape of South Africa, where fire has been historically rare. In a single study I explored the fate of V. karroo seedlings (less than a year old) following browsing in sub canopy and inter canopy microhabitats. Additionally, I explored how the fate of a seedling changed under high and low tree cover. Firstly, I investigated the type, intensity and frequency of herbivory, from both small and large herbivores, which seedlings were subjected to. Results revealed that browsing was severe and frequent with the majority of seedlings browsed more than twice over a 12 month period. Large browsers such as kudu and impala caused high seedling mortality (46%) while smaller browsers such as invertebrates were more effective at suppressing growth. Microhabitat had little impact on seedling survival, but significantly influenced plant compensatory growth. Reduced seedling growth following browsing was observed in the sub-canopy in comparison to seedling growth in full sunlight in the intercanopy, suggesting V.karroo may be shade intolerant. Secondly, the effect of tree cover on browsed seedlings was determined by quantifying browsing frequency and intensity at high and low tree cover. No differences in browsing intensity and frequency were observed between high and low tree cover. However, high tree cover due to bush encroachment limited seedling above ground growth. The aim of the second study was to investigate how V.karroo survival and growth were influenced by its age and size following simulated browsing. I explored this aim through field and greenhouse experiments. I was particularly interested in testing how plant sensitivity to varying defoliation intensities of repeated browsing varied with plant age (known ages of 6, 12, 16 and 30 weeks). There were large differences in mortality between the different age groups. Furthermore, age interacted with repeated browsing and negatively influenced seedling survival and regrowth. Older seedlings (16 and 30 week old) had greater survival and higher browsing frequencies resulted in greater mortality and reduced growth. The threshold age after which seedlings become more tolerant to herbivory occurs at an age of 28 weeks. Seedlings less than six weeks old experiencing intense (100 % defoliation)browsing had a very low probability (33%) of survival following just a single defoliation. Interestingly, all 16 week old seedlings regrew most of their foliage following a moderate (50%) defoliation with some plants overcompensating for leaf loss. The field study revealed two distinct demographic stages based on age and size (seedlings< 9 mm and saplings >9 mm in stem basal diameter (SBD)). Browsing had a strong negative effect on seedlings, resulting in reduced investment in leaf biomass. These findings suggest plant size and age can be used as robust predictors of a plants vulnerability to browsing. An increase in tree cover requires successful transitions of seedlings to saplings (also known as release). The results of this study suggest that in semi-arid savannas, browsing can impact tree cover through imposing a release bottleneck for tree seedlings and to lesser extent saplings. By limiting tree growth plants are kept in a disturbance trap and will therefore be exposed to not only browsers but fire. These findings also have important implications for tree-grass coexistence dynamics, suggesting that specific size and browsing thresholds should be considered in savanna management.
- Full Text:
- Date Issued: 2017
The socio-economic contribution of non-timber forest product trade to households in four villages in Zomba and Machinga Districts, Malawi
- Authors: Mahonya, Sophie Manchichi
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4787 , vital:20724
- Description: The principal aim of this study was to assess the socio-economic contribution of nontimber forest product (NTFP) trade to households in Zomba and Machinga, southern Malawi. Quantitative and qualitative data were collected through several methods, including a household survey using questionnaire interviews, focus group discussions, key informant interviews with individual traders, direct observations, and literature review. The quantitative data were analysed statistically using SPPS version 16.0 while the qualitative data were analysed thematically. NTFP trade was the third important source of cash income for 15% of the households, although the level of use, buying and selling of NTFPs varied across the four study villages. All households in all the study villages used firewood (100%), and most used thatch grass (94%), bamboo (96%), wood for building (92%), largely as construction materials. However, the percentage of households buying NTFPs was lower, with the maximum percentage of households being 50%. The percent of households engaged in selling at least one NTFP was lower still at 39%. Substantial cash incomes were generated from firewood and edible orchids sales which provided up to a maximum of Mk180,000, equivalent to US$456, per year. Households joined the trade mostly for an alternative source of cash income due to poverty and to meet basic needs when other options were not available or feasible. Cash income generated from NTFP trade acted as a safety net and a coping strategy when other avenues supporting livelihoods were not accessible. The socio-economic benefits derived from NTFP trade were associated with the quantities collected, sold, market forces influenced by the law of demand and supply. The small amounts of cash income generated by most households were important as they supplemented household cash needs. There was a strong association between NTFP trade as one of the important sources of cash income and the number of months a household had food from their own garden in a year. There was a significant relationship though weak between ranking of NTFP trade and livestock ownership by households. Value chain analysis was used as an analytical tool to understand the processes involved in NTFP trade. The value chains for the products under study were short, dominated by traders and some intermediaries. Most of the products were sold in local markets with little value addition. This study recommends that policy makers should integrate NTFPs into their development plans, emphasizing the establishment of management strategies that will enhance availability and sustainability of the resource. NTFPs contributed to the livelihoods of the households socially and economically through provision of food, cash income, energy for cooking, medicine and construction materials.
- Full Text:
- Date Issued: 2017
- Authors: Mahonya, Sophie Manchichi
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4787 , vital:20724
- Description: The principal aim of this study was to assess the socio-economic contribution of nontimber forest product (NTFP) trade to households in Zomba and Machinga, southern Malawi. Quantitative and qualitative data were collected through several methods, including a household survey using questionnaire interviews, focus group discussions, key informant interviews with individual traders, direct observations, and literature review. The quantitative data were analysed statistically using SPPS version 16.0 while the qualitative data were analysed thematically. NTFP trade was the third important source of cash income for 15% of the households, although the level of use, buying and selling of NTFPs varied across the four study villages. All households in all the study villages used firewood (100%), and most used thatch grass (94%), bamboo (96%), wood for building (92%), largely as construction materials. However, the percentage of households buying NTFPs was lower, with the maximum percentage of households being 50%. The percent of households engaged in selling at least one NTFP was lower still at 39%. Substantial cash incomes were generated from firewood and edible orchids sales which provided up to a maximum of Mk180,000, equivalent to US$456, per year. Households joined the trade mostly for an alternative source of cash income due to poverty and to meet basic needs when other options were not available or feasible. Cash income generated from NTFP trade acted as a safety net and a coping strategy when other avenues supporting livelihoods were not accessible. The socio-economic benefits derived from NTFP trade were associated with the quantities collected, sold, market forces influenced by the law of demand and supply. The small amounts of cash income generated by most households were important as they supplemented household cash needs. There was a strong association between NTFP trade as one of the important sources of cash income and the number of months a household had food from their own garden in a year. There was a significant relationship though weak between ranking of NTFP trade and livestock ownership by households. Value chain analysis was used as an analytical tool to understand the processes involved in NTFP trade. The value chains for the products under study were short, dominated by traders and some intermediaries. Most of the products were sold in local markets with little value addition. This study recommends that policy makers should integrate NTFPs into their development plans, emphasizing the establishment of management strategies that will enhance availability and sustainability of the resource. NTFPs contributed to the livelihoods of the households socially and economically through provision of food, cash income, energy for cooking, medicine and construction materials.
- Full Text:
- Date Issued: 2017
Evaluation of some pseudomonas species isolated from Hogsback forest reserve for the production of antibacterial compounds
- Authors: Mkono, Yonela Pelokazi
- Date: 2017
- Subjects: Bacteriology -- South Africa -- Eastern Cape Pseudomonas
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5961 , vital:29458
- Description: Pseudomonas species are Gram-negative bacteria most abundant in soil and water bodies, with the capacity to thrive in varied environments. They are largely associated with resistant pathogenic bacteria linked to human and plant diseases. Species such as Pseudomonas aeruginosa have been particularly targeted as case studies due to the extremity to which they pose a threat to human health. With more focus directed at using these species for biocontrol and bioremediation purposes, their role in bioactive compound production may be equally important. As the crisis on antimicrobial resistance still persists, the need for effective antimicrobial compounds is ever more urgent and solutions may possibly still be dormant in bacterial species whose potential has not been fully investigated. On a bid to source out potential antimicrobial compound producers, soil samples were collected from Hogback forest reserve in the province of the Eastern Cape, South Africa. For bacterial screening, M1 and R2A agar were used and the cultures grown at 37˚C for a period of seven days. After the presumed Pseudomonas species were identified, antimicrobial production was determined by submerged fermentation method using nutrient broth as media of choice. Active isolates were further studied to determine the optimum conditions which best facilitate for antimicrobial compound production, with parameters such as temperature (25˚C – 40˚C) and pH (4 – 9) considered. The role plasmids play in antimicrobial compound production was also investigated. Each isolate was grown in fermentation media containing Sodium dodecyl sulphate and Ethedium Bromide, at varying concentrations, to facilitate for plasmid curing. With each sample, distinct colonies were identified with varying pigmentations most dominant being a cream colour. The identity of the isolated strains was achieved through sequencing of 16S rDNA. Phylogenetic analysis showed that isolate A16 had 80 percent homology with Pseudomonas plecoglossicida strain P4 and share a close ancestor with isolates Y52 and Y81, also isolate Y89 showed a 90 percent homology with Pseudomonas sp. Co-11a. With the exception of isolate A16, the isolates which were active against Gram-negative bacteria lost activity as the screening processes continued. When looking at temperature variations, isolates Y81 and A16 were highly active with maximum activity observed at 35˚C while Y89 performed best at 25˚C and Y52 showed constant activity across all studied temperatures. The plasmids in all isolates were found to be 48.5 kb in size with the exception of isolate Y89 which was 20 kb. The plasmids were cured at concentrations of (1 mg/ml; 5 mg/ml; 7 mg/ml; 10 mg/ml; 11 mg/ml) SDS and (125 μg/ml; 6.5 μg/ml; 5μg/ml) EtBr. The curing process also showed changes in both the antimicrobial activity of the isolates as well as their physical characteristics. The isolates are the first reported Pseudomonas species from Hogsback forest reserve with the ability to produce antimicrobial compounds which are active against Gram-positive and Gram-negative bacteria. These mesophilic bacteria also show that plasmids do not pay any role in the production of antimicrobial compounds and that the biosynthesis genes are highly likely to be chromosomal borne meaning that the production cannot be linked to horizontal transfer of genes. Therefore, these isolated Pseudomonas species provide a potential reservoir of antimicrobial compounds which may play an important role in the antimicrobial resistance phenomenon.
- Full Text:
- Date Issued: 2017
- Authors: Mkono, Yonela Pelokazi
- Date: 2017
- Subjects: Bacteriology -- South Africa -- Eastern Cape Pseudomonas
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5961 , vital:29458
- Description: Pseudomonas species are Gram-negative bacteria most abundant in soil and water bodies, with the capacity to thrive in varied environments. They are largely associated with resistant pathogenic bacteria linked to human and plant diseases. Species such as Pseudomonas aeruginosa have been particularly targeted as case studies due to the extremity to which they pose a threat to human health. With more focus directed at using these species for biocontrol and bioremediation purposes, their role in bioactive compound production may be equally important. As the crisis on antimicrobial resistance still persists, the need for effective antimicrobial compounds is ever more urgent and solutions may possibly still be dormant in bacterial species whose potential has not been fully investigated. On a bid to source out potential antimicrobial compound producers, soil samples were collected from Hogback forest reserve in the province of the Eastern Cape, South Africa. For bacterial screening, M1 and R2A agar were used and the cultures grown at 37˚C for a period of seven days. After the presumed Pseudomonas species were identified, antimicrobial production was determined by submerged fermentation method using nutrient broth as media of choice. Active isolates were further studied to determine the optimum conditions which best facilitate for antimicrobial compound production, with parameters such as temperature (25˚C – 40˚C) and pH (4 – 9) considered. The role plasmids play in antimicrobial compound production was also investigated. Each isolate was grown in fermentation media containing Sodium dodecyl sulphate and Ethedium Bromide, at varying concentrations, to facilitate for plasmid curing. With each sample, distinct colonies were identified with varying pigmentations most dominant being a cream colour. The identity of the isolated strains was achieved through sequencing of 16S rDNA. Phylogenetic analysis showed that isolate A16 had 80 percent homology with Pseudomonas plecoglossicida strain P4 and share a close ancestor with isolates Y52 and Y81, also isolate Y89 showed a 90 percent homology with Pseudomonas sp. Co-11a. With the exception of isolate A16, the isolates which were active against Gram-negative bacteria lost activity as the screening processes continued. When looking at temperature variations, isolates Y81 and A16 were highly active with maximum activity observed at 35˚C while Y89 performed best at 25˚C and Y52 showed constant activity across all studied temperatures. The plasmids in all isolates were found to be 48.5 kb in size with the exception of isolate Y89 which was 20 kb. The plasmids were cured at concentrations of (1 mg/ml; 5 mg/ml; 7 mg/ml; 10 mg/ml; 11 mg/ml) SDS and (125 μg/ml; 6.5 μg/ml; 5μg/ml) EtBr. The curing process also showed changes in both the antimicrobial activity of the isolates as well as their physical characteristics. The isolates are the first reported Pseudomonas species from Hogsback forest reserve with the ability to produce antimicrobial compounds which are active against Gram-positive and Gram-negative bacteria. These mesophilic bacteria also show that plasmids do not pay any role in the production of antimicrobial compounds and that the biosynthesis genes are highly likely to be chromosomal borne meaning that the production cannot be linked to horizontal transfer of genes. Therefore, these isolated Pseudomonas species provide a potential reservoir of antimicrobial compounds which may play an important role in the antimicrobial resistance phenomenon.
- Full Text:
- Date Issued: 2017
The prospects of commercialising small-scale chicken production in Buffalo City metropolitan municipality, Eastern Cape province, South Africa
- Authors: Seti, Thembalethu Macdonald
- Date: 2017
- Subjects: Farms, Small -- South Africa -- Eastern Cape Poultry -- Breeding -- South Africa -- Eastern Cape Chicken industry -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15244 , vital:40257
- Description: The aim of this study is to explore the prospects of commercialising small-scale chicken production in Buffalo City Metropolitan Municipality, Eastern Cape. In the attempt of exploring these prospects, the researcher sought to understand socio-economic characteristics of small-scale chicken farmers, describe the small-scale chicken enterprise, and determine farmer’s level of commercialisation and factors influencing the farmer’s commercialisation level. Stratified random sampling was used to select 99 participants in the study area. The sampled participants constituted small-scale chicken farmers that were supported by government projects and farmers that were not part of any government support. Descriptive statistics, Household Commercialization Index (HCI) and Multinomial Regression model were used to analyse data and bring meaning to it. The results of the study signify that most of the farmers (66percent) are subsistence oriented, meaning most of their produce is consumed within the household and about 40percent are semi-commercial and only 7percent are at full commercialization meaning they only produce for the market. The result also showed that access to extension services (p<0.03), gender (p<0.03) household size (permanent family members) (p<0.01), transport cost (p<0.04), farming experience (p<0.02, grades and standards (p<0.01), production machines (p<0.05), and distance to the market (p<0.05) were the major determinants influencing output commercialization in the study area. The major constraints to production identified and prioritized by farmers were lack of feed, disease outbreaks, high mortality rate and theft. Based on the study results, to bring about the prospects of commercialising small-scale chicken, government should consistently supply extension officers, government investment in poultry machines and transport is also recommended. In terms of further research, the study suggests that research on profitability of small-scale chicken production would yield immense insights for policy development.
- Full Text:
- Date Issued: 2017
- Authors: Seti, Thembalethu Macdonald
- Date: 2017
- Subjects: Farms, Small -- South Africa -- Eastern Cape Poultry -- Breeding -- South Africa -- Eastern Cape Chicken industry -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15244 , vital:40257
- Description: The aim of this study is to explore the prospects of commercialising small-scale chicken production in Buffalo City Metropolitan Municipality, Eastern Cape. In the attempt of exploring these prospects, the researcher sought to understand socio-economic characteristics of small-scale chicken farmers, describe the small-scale chicken enterprise, and determine farmer’s level of commercialisation and factors influencing the farmer’s commercialisation level. Stratified random sampling was used to select 99 participants in the study area. The sampled participants constituted small-scale chicken farmers that were supported by government projects and farmers that were not part of any government support. Descriptive statistics, Household Commercialization Index (HCI) and Multinomial Regression model were used to analyse data and bring meaning to it. The results of the study signify that most of the farmers (66percent) are subsistence oriented, meaning most of their produce is consumed within the household and about 40percent are semi-commercial and only 7percent are at full commercialization meaning they only produce for the market. The result also showed that access to extension services (p<0.03), gender (p<0.03) household size (permanent family members) (p<0.01), transport cost (p<0.04), farming experience (p<0.02, grades and standards (p<0.01), production machines (p<0.05), and distance to the market (p<0.05) were the major determinants influencing output commercialization in the study area. The major constraints to production identified and prioritized by farmers were lack of feed, disease outbreaks, high mortality rate and theft. Based on the study results, to bring about the prospects of commercialising small-scale chicken, government should consistently supply extension officers, government investment in poultry machines and transport is also recommended. In terms of further research, the study suggests that research on profitability of small-scale chicken production would yield immense insights for policy development.
- Full Text:
- Date Issued: 2017
The effects of terpenoids on the expression and function of cytokines and adipokines in pre-adipocytes and differentiated adipocytes
- Authors: Bloom, Carri-Ann
- Date: 2017
- Subjects: Terpenes , Cytokines , Fat cells
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9208 , vital:26479
- Description: CURRENTLY UNDER EMBARGO UNTIL THE 26/4/2019: Type 2 diabetes is a metabolic disorder characterised by inflammation, insulin resistance and the inability of pancreatic β-cells to secrete enough insulin to produce a physiological effect. Obesity and high levels of triacylglycerol’s are associated with the development of Type 2 diabetes. Adipose tissue is an active endocrine organ that secretes various protein and peptide hormones, known as adipokines, which mediate important metabolic functions. In an insulin resistant and hyperglycaemic state, levels of anti-inflammatory adipokines, adiponectin, are reduced, whereas levels of pro-inflammatory cytokines, interleukin-6 and interleukin-1β, are elevated; this results in a shift from an anti- to a pro-inflammatory state that is accompanied by dysfunction and apoptosis of the pancreatic β-cells. Cannabis sativa L. has been traditionally used as an anti-inflammatory agent in Southern Africa, specifically treating snakebites, fever and malaria. Δ9-tetrahydrocannabinol is the main psychoactive compound derived from C. sativa, whereas the other major cannabinoids, cannabinol and cannabidiol, have shown anti-inflammatory and sedative properties respectively. Marrubiin is a compound derived from the plant Leonotis leonurus L. and has been traditionally used as an anti-inflammatory and anti-diabetic agent. To determine the effects of these compounds in a hyperglycaemic state, pre- and differentiated mouse adipocytes (3T3-L1 cells) were exposed for seven and fourteen days to the following treatments: Δ9-tetrahydrocannabinol, cannabidiol, cannabinol, marrubiin, anandamide (an endogenous endocannabinoid) and cannabis extract, individually and in combination, under normal glucose and hyperglycaemic conditions. Levels of adiponectin, interleukin-6, leptin, tumour-necrosis factor-α and interleukin-1β were quantified using mouse enzyme-linked immunosorbent assay kits and Oil Red O staining was carried out to determine lipid distribution and lipid droplet characteristics. Results indicate that various cannabinoids, in combination, mediate an anti-inflammatory effect by decreasing the expression of various pro-inflammatory cytokines, which may have allowed for a shift from a pro- to an anti-inflammatory state by these compounds, and may also contribute to the reduction of lipid, which may be used as a supplementary option to current diabetic treatment regimes.
- Full Text: false
- Date Issued: 2017
- Authors: Bloom, Carri-Ann
- Date: 2017
- Subjects: Terpenes , Cytokines , Fat cells
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/9208 , vital:26479
- Description: CURRENTLY UNDER EMBARGO UNTIL THE 26/4/2019: Type 2 diabetes is a metabolic disorder characterised by inflammation, insulin resistance and the inability of pancreatic β-cells to secrete enough insulin to produce a physiological effect. Obesity and high levels of triacylglycerol’s are associated with the development of Type 2 diabetes. Adipose tissue is an active endocrine organ that secretes various protein and peptide hormones, known as adipokines, which mediate important metabolic functions. In an insulin resistant and hyperglycaemic state, levels of anti-inflammatory adipokines, adiponectin, are reduced, whereas levels of pro-inflammatory cytokines, interleukin-6 and interleukin-1β, are elevated; this results in a shift from an anti- to a pro-inflammatory state that is accompanied by dysfunction and apoptosis of the pancreatic β-cells. Cannabis sativa L. has been traditionally used as an anti-inflammatory agent in Southern Africa, specifically treating snakebites, fever and malaria. Δ9-tetrahydrocannabinol is the main psychoactive compound derived from C. sativa, whereas the other major cannabinoids, cannabinol and cannabidiol, have shown anti-inflammatory and sedative properties respectively. Marrubiin is a compound derived from the plant Leonotis leonurus L. and has been traditionally used as an anti-inflammatory and anti-diabetic agent. To determine the effects of these compounds in a hyperglycaemic state, pre- and differentiated mouse adipocytes (3T3-L1 cells) were exposed for seven and fourteen days to the following treatments: Δ9-tetrahydrocannabinol, cannabidiol, cannabinol, marrubiin, anandamide (an endogenous endocannabinoid) and cannabis extract, individually and in combination, under normal glucose and hyperglycaemic conditions. Levels of adiponectin, interleukin-6, leptin, tumour-necrosis factor-α and interleukin-1β were quantified using mouse enzyme-linked immunosorbent assay kits and Oil Red O staining was carried out to determine lipid distribution and lipid droplet characteristics. Results indicate that various cannabinoids, in combination, mediate an anti-inflammatory effect by decreasing the expression of various pro-inflammatory cytokines, which may have allowed for a shift from a pro- to an anti-inflammatory state by these compounds, and may also contribute to the reduction of lipid, which may be used as a supplementary option to current diabetic treatment regimes.
- Full Text: false
- Date Issued: 2017
Appropriate integration of workers with physical limitations into a manual workplace – development of an assessment tool
- Authors: Pearson, Jessie T
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/8209 , vital:21368
- Description: Background: People with physical limitations can contribute significantly to society and the economy, however, barriers to full and effective participation in the labour market often hinder decent employment. In light of this, placement decisions of impaired workers should be based on detailed information of the nature of the jobs available, as well as individual capabilities of the worker. An ergonomics approach to design attempts to achieve an appropriate balance between the capabilities of the worker and the requirements of the task and uses this balance to improve productivity and encourage physical and mental well-being, job satisfaction and safety. A specific analysis tool which can be applied to various workplaces and jobs, and provide information for decisions regarding placement of physically limited workers, will help to increase the percentage of correct placement in an appropriate workplace, resulting in optimum productivity and worker safety. Methods: An assessment tool which allows matching of job requirements and worker capabilities was developed based on a theoretical framework from Mattison and Goebel (2007), as well as principles defined by Almgren and Schaurig (2012) and Demura and Nakada (2010). The tool assesses range of motion, force and time components of the physical requirements of different tasks involved in the job, as well as movement capabilities and limitations of the worker. The tool was pilot tested in a case study with an above the knee amputee working at a research facility. Results: The tool successfully provided information regarding the matching of the work to the identified job. The output of the tool highlighted two tasks which would place the worker at risk due to physical requirements of the tasks being greater than movement capabilities of the worker. These tasks need to be further investigated to determine if accommodations can be made to assist the worker in safely performing the task, or if the job is not suitable for the worker. Conclusions: The tool developed was useful in providing information to inform appropriate placement of the physically limited worker. Further research needs to be done to validate and determine reliability of the tool.
- Full Text:
- Date Issued: 2017
- Authors: Pearson, Jessie T
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/8209 , vital:21368
- Description: Background: People with physical limitations can contribute significantly to society and the economy, however, barriers to full and effective participation in the labour market often hinder decent employment. In light of this, placement decisions of impaired workers should be based on detailed information of the nature of the jobs available, as well as individual capabilities of the worker. An ergonomics approach to design attempts to achieve an appropriate balance between the capabilities of the worker and the requirements of the task and uses this balance to improve productivity and encourage physical and mental well-being, job satisfaction and safety. A specific analysis tool which can be applied to various workplaces and jobs, and provide information for decisions regarding placement of physically limited workers, will help to increase the percentage of correct placement in an appropriate workplace, resulting in optimum productivity and worker safety. Methods: An assessment tool which allows matching of job requirements and worker capabilities was developed based on a theoretical framework from Mattison and Goebel (2007), as well as principles defined by Almgren and Schaurig (2012) and Demura and Nakada (2010). The tool assesses range of motion, force and time components of the physical requirements of different tasks involved in the job, as well as movement capabilities and limitations of the worker. The tool was pilot tested in a case study with an above the knee amputee working at a research facility. Results: The tool successfully provided information regarding the matching of the work to the identified job. The output of the tool highlighted two tasks which would place the worker at risk due to physical requirements of the tasks being greater than movement capabilities of the worker. These tasks need to be further investigated to determine if accommodations can be made to assist the worker in safely performing the task, or if the job is not suitable for the worker. Conclusions: The tool developed was useful in providing information to inform appropriate placement of the physically limited worker. Further research needs to be done to validate and determine reliability of the tool.
- Full Text:
- Date Issued: 2017
The sedimentology and depositional model of VS5 reef at Beatrix mine and surrounding areas of the Freestate Goldfield, South Africa
- Authors: Shivambu, Steven
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4942 , vital:20745
- Description: Historically, placers of economic importance at Sibanye Gold's Beatrix No. 3 Shaft were Beatrix Reef, Aandenk Reef and Composite of the two reefs. Recently, the VS5 placer has emerged to be a significant contributor of ore tonnages mined on the Shaft as mining advances into deeper levels towards the northern portion of the mine lease area. Gold concentration in the VS5 Reef is highly variable from uneconomic, through marginal to economic gold values. A good knowledge of the sedimentological framework of the VS5 Reef was considered necessary in order to interpret the variable distribution of the gold within the VS5 placer. The aim of this study was to determine the depositional environments that played a major role during the formation of the VS5 placer by means of investigating the macroscopic sedimentological parameters of this particular reef. These sedimentological parameters were used as the basis for the subdivision of VS5 Reef into different facies recognized in the mine and surrounding areas. It was recognized that the VS5 placer was formed in a distal, braided fluvial environment by the reworking of the pre-existing Aandenk Reef by new materials containing significant amount of nondurable materials (see definition on page xii) such as shale detritus. Where there is no evidence of reworking of the older Aandenk Reef, the VS5 Reef occurs as poorly sorted, polymictic conglomerate with abundance of non-durable detritus. This is referred to as the Immature (IV) VS5 facies and occurs in the northern portion of the study area. The degree of reworking of the gravel bars by waves and current action resulted in the formation of well sorted, oligomictic conglomerates of the Beatrix facies in the southern portion of the mine. At the boundaries between the Immature VS5 and Beatrix facies occurs the Transitional (Sub-mature) VS5 facies, characterized by reef comprising a polymictic upper portion and a basal more mature oligomictic unit. The Transitional VS5 facies extends across the current central northern mining faces of Beatrix No. 3 Shaft with a northwest-southeast trend. There is a strong correlation between the VS5 lithofacies and distribution of gold mineralization. The Immature VS5 facies is poorly mineralized, with gold values averaging 200 c.m.g/t and lower. The Transitional (Sub-mature) VS5 facies has elevated gold values, ranging from 300 c.m.g/t to 1500 cm.g/t. Mineralization in this unit tend to be bottom loaded as well as at the base of each cyclic unit. The Beatrix facies records the highest grades averaging >1500 cmg/t. The improved understanding of the VS5 lithofacies made it possible to predict gold mineralization and aid planning to mine into viable VS5 areas.
- Full Text:
- Date Issued: 2017
- Authors: Shivambu, Steven
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4942 , vital:20745
- Description: Historically, placers of economic importance at Sibanye Gold's Beatrix No. 3 Shaft were Beatrix Reef, Aandenk Reef and Composite of the two reefs. Recently, the VS5 placer has emerged to be a significant contributor of ore tonnages mined on the Shaft as mining advances into deeper levels towards the northern portion of the mine lease area. Gold concentration in the VS5 Reef is highly variable from uneconomic, through marginal to economic gold values. A good knowledge of the sedimentological framework of the VS5 Reef was considered necessary in order to interpret the variable distribution of the gold within the VS5 placer. The aim of this study was to determine the depositional environments that played a major role during the formation of the VS5 placer by means of investigating the macroscopic sedimentological parameters of this particular reef. These sedimentological parameters were used as the basis for the subdivision of VS5 Reef into different facies recognized in the mine and surrounding areas. It was recognized that the VS5 placer was formed in a distal, braided fluvial environment by the reworking of the pre-existing Aandenk Reef by new materials containing significant amount of nondurable materials (see definition on page xii) such as shale detritus. Where there is no evidence of reworking of the older Aandenk Reef, the VS5 Reef occurs as poorly sorted, polymictic conglomerate with abundance of non-durable detritus. This is referred to as the Immature (IV) VS5 facies and occurs in the northern portion of the study area. The degree of reworking of the gravel bars by waves and current action resulted in the formation of well sorted, oligomictic conglomerates of the Beatrix facies in the southern portion of the mine. At the boundaries between the Immature VS5 and Beatrix facies occurs the Transitional (Sub-mature) VS5 facies, characterized by reef comprising a polymictic upper portion and a basal more mature oligomictic unit. The Transitional VS5 facies extends across the current central northern mining faces of Beatrix No. 3 Shaft with a northwest-southeast trend. There is a strong correlation between the VS5 lithofacies and distribution of gold mineralization. The Immature VS5 facies is poorly mineralized, with gold values averaging 200 c.m.g/t and lower. The Transitional (Sub-mature) VS5 facies has elevated gold values, ranging from 300 c.m.g/t to 1500 cm.g/t. Mineralization in this unit tend to be bottom loaded as well as at the base of each cyclic unit. The Beatrix facies records the highest grades averaging >1500 cmg/t. The improved understanding of the VS5 lithofacies made it possible to predict gold mineralization and aid planning to mine into viable VS5 areas.
- Full Text:
- Date Issued: 2017
Consumers' attitudes towards ready-to-eat fast-food products and their relationship with obesity in Mdantsane township in the Eastern Cape Province, South Africa
- Authors: Matyolo, Pamela
- Date: 2017
- Subjects: Obesity -- South Africa -- Eastern Cape Obesity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9022 , vital:34183
- Description: The South African fast-food industry has experienced substantial recent growth. However, as consumers have incorporated more fast food into their daily diets, obesity has become a major problem. The aggressive marketing techniques of fast food firms coupled with the busy urban lifestyle have significant implications for dietary health habits. The study aimed at investigating consumers’ attitudes towards fast food and the relationship between fast food consumption and obesity. The field survey design of the study employed a mixed-methods approach involving the use of a semi-structured questionnaire. The study was limited to the Mdantsane Township located in the Eastern Cape Province of South Africa. A quota sample of 200 respondents (n = 200) was selected from which data were collected using a self-administered questionnaire. Descriptive results revealed that the participants had positive attitudes towards fast foods. Although they agreed that eating fast foods increased body weight, the participants mostly did not feel overweight or obese. The participants were well aware of the negative health implications of excessive fast food consumption. This knowledge generally did not deter their positive fast food attitudes, although participants expressed their desire for additional healthier fast food options in the market. Regression estimates further revealed that carbohydrate and starchy type of fast foods (𝑃 < 0.01), other sources of fast foods (𝑃 < 0.05), age group, physical appearance and meaty type of fast foods (𝑃 < 0.10) had significant influence on the frequency of fast food consumption. The results further revealed that physical appearance (𝑃 < 0.01), religion (𝑃 < 0.05), age group and supermarkets and source of fast foods (𝑃 < 0.1) had significant influence on respondents’ BMI scores. The study concludes that there exist socio-economic and institutional factors that have considerable bearing on consumers’ fast food consumption and BMI scores. The study advocates for public health policy making concerning awareness of the negative health consequences of fast food consumption targeting mostly young adult females who mainly purchase in franchises and supermarkets with a high meaty diet.
- Full Text:
- Date Issued: 2017
- Authors: Matyolo, Pamela
- Date: 2017
- Subjects: Obesity -- South Africa -- Eastern Cape Obesity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9022 , vital:34183
- Description: The South African fast-food industry has experienced substantial recent growth. However, as consumers have incorporated more fast food into their daily diets, obesity has become a major problem. The aggressive marketing techniques of fast food firms coupled with the busy urban lifestyle have significant implications for dietary health habits. The study aimed at investigating consumers’ attitudes towards fast food and the relationship between fast food consumption and obesity. The field survey design of the study employed a mixed-methods approach involving the use of a semi-structured questionnaire. The study was limited to the Mdantsane Township located in the Eastern Cape Province of South Africa. A quota sample of 200 respondents (n = 200) was selected from which data were collected using a self-administered questionnaire. Descriptive results revealed that the participants had positive attitudes towards fast foods. Although they agreed that eating fast foods increased body weight, the participants mostly did not feel overweight or obese. The participants were well aware of the negative health implications of excessive fast food consumption. This knowledge generally did not deter their positive fast food attitudes, although participants expressed their desire for additional healthier fast food options in the market. Regression estimates further revealed that carbohydrate and starchy type of fast foods (𝑃 < 0.01), other sources of fast foods (𝑃 < 0.05), age group, physical appearance and meaty type of fast foods (𝑃 < 0.10) had significant influence on the frequency of fast food consumption. The results further revealed that physical appearance (𝑃 < 0.01), religion (𝑃 < 0.05), age group and supermarkets and source of fast foods (𝑃 < 0.1) had significant influence on respondents’ BMI scores. The study concludes that there exist socio-economic and institutional factors that have considerable bearing on consumers’ fast food consumption and BMI scores. The study advocates for public health policy making concerning awareness of the negative health consequences of fast food consumption targeting mostly young adult females who mainly purchase in franchises and supermarkets with a high meaty diet.
- Full Text:
- Date Issued: 2017
Evaluation of the socio-economic performance of smallholder irrigation schemes in Idutywa Village of the Eastern Cape Province
- Authors: Jiba, Phiwe
- Date: 2017
- Subjects: Irrigation farming -- Economic aspects Farms, Small -- South Africa -- Eastern Cape Agricultural development projects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4705 , vital:28497
- Description: South Africa and other African countries are faced with high levels of food insecurity and poverty levels as a result of slow growth of the macro economy and weak or sluggish rural development. Irrigation scheme development is seen as an important strategy to address the challenges faced by households in rural areas and restores growth and enhanced livelihoods. While the international experience shows that Irrigation schemes are potentially transformative of poor communities and have been operational for many years now, there is no marked improvement in living conditions of rural households in terms of livelihoods and income. This raises the question as to whether or not the schemes are viable from a socio-economic perspective and whether or not there are reasons for concern and revision of the policy framework for smallholder irrigation schemes. As a result of that, the broad objective of the study was to evaluate the contribution of smallholder irrigation schemes to household income and food security of rural households in Idutywa village of the Eastern Cape Province in South Africa. Specifically, this research investigated the major factors that influence their performance, impact of irrigation farming on rural livelihood and household food security as well as identifying the possible opportunities of production that would improve their performance. The study was carried out in Idutywa villages of the Eastern Cape Province in South Africa and employed survey data obtained from 107 households. The study employed a cross-sectional research design and the study employed stratified random sampling. The study made use of descriptive and inferential statistics to estimate the central tendency and dispersion as well as testing the hypothesis that there is a difference in the contribution between irrigators and non-irrigators using STATA and SPSS. Probit regression model was used to estimate factors that influenced the performance of smallholder irrigation schemes. The descriptive statistics employed included means, percentages and frequencies on the socio-economic characteristics of households in the study areas. The results show that females were dominant with a representation of 66.7 percent. The majority of households were aged and the mean age was 65 years. High level of illiteracy in the project area was revealed by the data. The average number of years, households spent in school was between 6 years to 10 years in school. Farming was found to be the major agricultural economic activity. Sixty-three (63 percent) were full time farmers. The results further show that household size ranges between 1 to 5 persons. The households were shown to be mostly dependent on social grant with household income hovering around R 1 000. The results from propensity score matching revealed that irrigation exerts a positive impact on household income. This provides sufficient evidence that irrigation schemes do make a contribution to rural livelihoods through their effect on household income and food security. This implies that government should continue investing in irrigation schemes as part of a strategy to grow the rural economy and improve rural livelihoods. This is in line with the Agricultural Policy Action Plan (APAP) and National Development Plan (NDP) of South Africa. Probit analysis suggests that age of the households, household size and market were some of the key determinants that positively influenced households’ decision to participate in smallholder irrigation schemes while access to credit had significant but negative effect on households’ decision to participate in smallholder irrigation schemes. Based on the findings highlighted above, it is recommended that addressing such barriers may create enabling conditions that would encourage households to access and participate more effectively in smallholder irrigation schemes.
- Full Text:
- Date Issued: 2017
- Authors: Jiba, Phiwe
- Date: 2017
- Subjects: Irrigation farming -- Economic aspects Farms, Small -- South Africa -- Eastern Cape Agricultural development projects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4705 , vital:28497
- Description: South Africa and other African countries are faced with high levels of food insecurity and poverty levels as a result of slow growth of the macro economy and weak or sluggish rural development. Irrigation scheme development is seen as an important strategy to address the challenges faced by households in rural areas and restores growth and enhanced livelihoods. While the international experience shows that Irrigation schemes are potentially transformative of poor communities and have been operational for many years now, there is no marked improvement in living conditions of rural households in terms of livelihoods and income. This raises the question as to whether or not the schemes are viable from a socio-economic perspective and whether or not there are reasons for concern and revision of the policy framework for smallholder irrigation schemes. As a result of that, the broad objective of the study was to evaluate the contribution of smallholder irrigation schemes to household income and food security of rural households in Idutywa village of the Eastern Cape Province in South Africa. Specifically, this research investigated the major factors that influence their performance, impact of irrigation farming on rural livelihood and household food security as well as identifying the possible opportunities of production that would improve their performance. The study was carried out in Idutywa villages of the Eastern Cape Province in South Africa and employed survey data obtained from 107 households. The study employed a cross-sectional research design and the study employed stratified random sampling. The study made use of descriptive and inferential statistics to estimate the central tendency and dispersion as well as testing the hypothesis that there is a difference in the contribution between irrigators and non-irrigators using STATA and SPSS. Probit regression model was used to estimate factors that influenced the performance of smallholder irrigation schemes. The descriptive statistics employed included means, percentages and frequencies on the socio-economic characteristics of households in the study areas. The results show that females were dominant with a representation of 66.7 percent. The majority of households were aged and the mean age was 65 years. High level of illiteracy in the project area was revealed by the data. The average number of years, households spent in school was between 6 years to 10 years in school. Farming was found to be the major agricultural economic activity. Sixty-three (63 percent) were full time farmers. The results further show that household size ranges between 1 to 5 persons. The households were shown to be mostly dependent on social grant with household income hovering around R 1 000. The results from propensity score matching revealed that irrigation exerts a positive impact on household income. This provides sufficient evidence that irrigation schemes do make a contribution to rural livelihoods through their effect on household income and food security. This implies that government should continue investing in irrigation schemes as part of a strategy to grow the rural economy and improve rural livelihoods. This is in line with the Agricultural Policy Action Plan (APAP) and National Development Plan (NDP) of South Africa. Probit analysis suggests that age of the households, household size and market were some of the key determinants that positively influenced households’ decision to participate in smallholder irrigation schemes while access to credit had significant but negative effect on households’ decision to participate in smallholder irrigation schemes. Based on the findings highlighted above, it is recommended that addressing such barriers may create enabling conditions that would encourage households to access and participate more effectively in smallholder irrigation schemes.
- Full Text:
- Date Issued: 2017