A qualitative study of the psychosocial well-being of adolescent females orphaned by HIV/AIDS in Nkonkobe Municipality
- Authors: Mahola, Mpho Nosisi
- Date: 2018
- Subjects: Children of AIDS patients Orphans -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/10818 , vital:35807
- Description: Approximately twelve million children under the age of 18 years worldwide have lost one or both parents due to HIV/AIDS. Several factors can be considered to contribute to the psychosocial well-being of HIV/AIDS orphaned teenage girls, among others, poverty, lack of social support, post-traumatic stress disorder, stigma and discrimination which have adverse consequences to the said teenager. Evidence suggests that HIV/AIDS orphaned adolescent girls may engage in relationships with older men to fund for school and other expenses and also to fulfil the need for a parental figure or emotional support, affection and attention. Against this background, this research study intended to investigate the psychosocial wellbeing of adolescent females orphaned by HIV/AIDS in the Nkonkobe Municipality. Fourteen Xhosa- speaking adolescent females between the ages of 15 and 18 years were recruited by means of snowball technique to participate in a qualitative study. Semi-structured interviews allowed sensitive issues to be discussed more easily. To ensure confidentiality and anonymity, the researcher suggested pseudonyms for the participants. This took place after the management of Isibindi Community Centre from Alice and Child Welfare from Fort Beaufort, both from the Eastern Cape, South Africa granted permission to conduct the study. The social worker from child welfare and the principal of Lingeni High School, assisted in ensuring that the participants from the two data collection sites, are organized prior the study. The researcher used Guba’s model whereby Guba and Lincoln’s model to ascertain the trustworthiness of qualitative research by following these principles; credibility, dependability, transferability and confirmability. The framework analysis which uses a thematic approach was utilized to analyse data. Meanings were formulated and they produced clusters of themes. The findings of the study revealed that HIV/AIDS orphaned adolescent females experienced grief of the loss of parents which made it difficult by deepening poverty and multifaceted challenges. Participants’ psychological well-being was impaired, subsequently they engaged in risky sexual behaviour, that is, substance abuse and multiple sexual partnership. However, an element of hardiness emanated from the participants’ personalities. They demonstrated problem-focused coping with the challenges they confront, despite the lack of consistent support structures. Their resiliency and sense of belonging owing to the nature of support from extended families ignited a sense of purpose amongst the participants. In conclusion, it is recommended that children orphaned by HIV/AIDS should be told of the cause of the death of their parents as this will make them aware of the dangers and consequences of their actions.
- Full Text:
- Date Issued: 2018
- Authors: Mahola, Mpho Nosisi
- Date: 2018
- Subjects: Children of AIDS patients Orphans -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/10818 , vital:35807
- Description: Approximately twelve million children under the age of 18 years worldwide have lost one or both parents due to HIV/AIDS. Several factors can be considered to contribute to the psychosocial well-being of HIV/AIDS orphaned teenage girls, among others, poverty, lack of social support, post-traumatic stress disorder, stigma and discrimination which have adverse consequences to the said teenager. Evidence suggests that HIV/AIDS orphaned adolescent girls may engage in relationships with older men to fund for school and other expenses and also to fulfil the need for a parental figure or emotional support, affection and attention. Against this background, this research study intended to investigate the psychosocial wellbeing of adolescent females orphaned by HIV/AIDS in the Nkonkobe Municipality. Fourteen Xhosa- speaking adolescent females between the ages of 15 and 18 years were recruited by means of snowball technique to participate in a qualitative study. Semi-structured interviews allowed sensitive issues to be discussed more easily. To ensure confidentiality and anonymity, the researcher suggested pseudonyms for the participants. This took place after the management of Isibindi Community Centre from Alice and Child Welfare from Fort Beaufort, both from the Eastern Cape, South Africa granted permission to conduct the study. The social worker from child welfare and the principal of Lingeni High School, assisted in ensuring that the participants from the two data collection sites, are organized prior the study. The researcher used Guba’s model whereby Guba and Lincoln’s model to ascertain the trustworthiness of qualitative research by following these principles; credibility, dependability, transferability and confirmability. The framework analysis which uses a thematic approach was utilized to analyse data. Meanings were formulated and they produced clusters of themes. The findings of the study revealed that HIV/AIDS orphaned adolescent females experienced grief of the loss of parents which made it difficult by deepening poverty and multifaceted challenges. Participants’ psychological well-being was impaired, subsequently they engaged in risky sexual behaviour, that is, substance abuse and multiple sexual partnership. However, an element of hardiness emanated from the participants’ personalities. They demonstrated problem-focused coping with the challenges they confront, despite the lack of consistent support structures. Their resiliency and sense of belonging owing to the nature of support from extended families ignited a sense of purpose amongst the participants. In conclusion, it is recommended that children orphaned by HIV/AIDS should be told of the cause of the death of their parents as this will make them aware of the dangers and consequences of their actions.
- Full Text:
- Date Issued: 2018
An investigation of the role of a selected out of school time reading programme on learners’ reading behaviours and attitudes
- Authors: Williams, Sarah Marcella
- Date: 2017
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/7511 , vital:21268
- Description: Due to the lingering damage from the Apartheid era and Bantu education, South Africa is still battling to rectify the inequalities in schools in previously disadvantaged areas. The lack of a reading culture and very poor literacy assessment scores in these areas is cause to include even out-of-school time to help remedy these problems. This study seeks to add to the body of literature by investigating the influence of two selected out-of-school time reading programmes on learners’ reading attitudes and behaviours within the South African context. Drawing from the New Literacy Studies (Gee, 1991; Street, 1995) and the Theory of Planned Behaviour (Ajzen, 1991), this Mixed- Method approach study examined the role that two out of school reading programmes played in the development of reading behaviours and attitudes of learners from township area called Simonstown, in the Eastern Cape Province. Located within the Pragmativist Paradigm, Mixed Method Research Approach, and Explanatory Design Method as a research design, the study used pre- and post-intervention quantitative questionnaires, semi-structured interpreter-facilitated interviews, structured observations, and the out of school reading programme as an intervention to generate data. The research site and study participants were purposively selected. They included 10 learners from 2 out of school reading programmes that benefited from funding and literacy project training and support called Nal’ibali. The study was designed to evaluate the effectiveness of these out of school reading programmes in improving learners reading behaviours and attitudes, and how the OST reading programmes influenced the reading behaviours and attitudes of the parents. Findings from the data concluded that the certain factors in the OST reading programme in conjunction with the positive influence of the parents and siblings own reading attitudes had a positive effect on learners’ reading attitudes and behaviours.
- Full Text:
- Date Issued: 2017
- Authors: Williams, Sarah Marcella
- Date: 2017
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/7511 , vital:21268
- Description: Due to the lingering damage from the Apartheid era and Bantu education, South Africa is still battling to rectify the inequalities in schools in previously disadvantaged areas. The lack of a reading culture and very poor literacy assessment scores in these areas is cause to include even out-of-school time to help remedy these problems. This study seeks to add to the body of literature by investigating the influence of two selected out-of-school time reading programmes on learners’ reading attitudes and behaviours within the South African context. Drawing from the New Literacy Studies (Gee, 1991; Street, 1995) and the Theory of Planned Behaviour (Ajzen, 1991), this Mixed- Method approach study examined the role that two out of school reading programmes played in the development of reading behaviours and attitudes of learners from township area called Simonstown, in the Eastern Cape Province. Located within the Pragmativist Paradigm, Mixed Method Research Approach, and Explanatory Design Method as a research design, the study used pre- and post-intervention quantitative questionnaires, semi-structured interpreter-facilitated interviews, structured observations, and the out of school reading programme as an intervention to generate data. The research site and study participants were purposively selected. They included 10 learners from 2 out of school reading programmes that benefited from funding and literacy project training and support called Nal’ibali. The study was designed to evaluate the effectiveness of these out of school reading programmes in improving learners reading behaviours and attitudes, and how the OST reading programmes influenced the reading behaviours and attitudes of the parents. Findings from the data concluded that the certain factors in the OST reading programme in conjunction with the positive influence of the parents and siblings own reading attitudes had a positive effect on learners’ reading attitudes and behaviours.
- Full Text:
- Date Issued: 2017
Evaluation of some pharmaceutical and personal care products and pesticide residues in selected wastewater treatment plants and receiving watersheds in Eastern Cape, South Africa
- Ademoyegun, Olufemi Temitope
- Authors: Ademoyegun, Olufemi Temitope
- Date: 2017
- Subjects: Emerging contaminants in water -- South Africa -- Eastern Cape Water treatment plants -- Waste disposal -- South Africa -- Eastern Cape Organic compounds -- Environmental aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2922 , vital:28138
- Description: Emerging organic contaminants (EOCs) have been the focus of global environmental research for over three decades. EOCs have caused widespread concern due to their extensive use. As EOCs were designed to correct, enhance or protect a specific physiological, their target effects in humans and/or farm stocks are relatively well known and documented. However, there is limited knowledge about their unintended effects in the environment. To address the occurrence, distribution and fate of EOCs in the environment, efficient and reliable analytical methods are needed. The relatively low concentration, high polarity, and thermal lability of some EOCs, together with their interaction with complex environmental matrices, make their analysis challenging. Sample preparation followed by GC or HPLC separation and mass spectrometry (MS) detection has become the standard approach for evaluating EOCs in environmental samples. Physicochemical properties of EOCs range from highly water-soluble (hydrophylic) to highly water-insoluble (hydrophobic). Two groups of these EOCs were considered for study in this work. Pharmaceutical and personal care products (PPCPs) were comprehensively studied in five wastewater treatment plants and their receiving watersheds in Amathole districts in Eastern C ape, South Africa. PPCPs have been widely reported in wastewater influents, effluents, receiving rivers and biosolids, but reports of their occurrence in all these matrixes have been limited by the difficulty of analysis. Therefore, a comprehensive validation of methods was carried out on the influents, effluents, sludge and soil from the irrigated golf course where the effluent of one of the study sites was being used for over three decades now for irrigation. In all, thirteen PPCPs from five therapeutic groups were selected for study in this work because of their administering rate and availability of analytical instrument. Good limit of detection (LOD) and limit of quantification (LOQ) were achieved for the method used. The LOD for the aqueous Three different technologies were employed for the treatment of wastewater in the five selected wastewater treatment plants (WWTPs) and study was carried out to evaluate their ability to eliminate the selected compounds from the influents to the effluents using statistical analysis (ANOVA) at p<0.05 on the percentage removal rate across the three plants. The results had shown eight of the compounds having no significant difference among the treatment operations, whereas the remaining five compounds varied significantly among the treatment technologies under investigation. Principal component analysis was performed on the concentration of PPCPs, their removal rate and also on the physicochemical and treatment operation parameters. Hydraulic retention time (HRT) had correlation coefficient, r = 0.90 with the concentration of PPCPs and removal rates. Furthermore, occurrences, seasonal variation, mean concentration distribution pattern of the compounds, and temporal evaluation of the mean concentration of the pharmaceutical compounds in the five WWTPs during one year of sampling were considered. The results revealed that five products which were diclofenac, ibuprofen, paracetamol, triclosan and diethyl toluamide (DDET) were predominant among the PPCPs in all the WWTPs. The removal efficiency was highest in caffeine with 96 percent, and the lowest was obtained with carbamazepine (4 percent). Risk quotient of the concentration of PPCPs in the effluents and receiving waters was determined to assess their chronic toxicity at three trophic levels: fish, algae and matrixes studied ranged from 0.01 μg/L to 0.25 μg/L, and the LOQ from 0.02 μg/L to 0.78 μg/L. In the solid matrixes, LOD varied from 0.01 ng/g to 0.65 ng/g, and the LOQ between 0.08 ng/g and 5.17 ng/g. Better recovery efficiency was obtained with this mixture of solvents, acetone: dichloromethane (1:1), for the recovery of the five therapeutic groups in the solid matrixes using ultrasonication- assisted techniques. The results show percentage recovery values ranging from 68.8 percent to 107.5 percent diaphian. According to the environmental risk assessment results, ibuprofen and triclosan were found to be the most critical compounds due to their high risk quotient values. These findings will, therefore, help in the future evaluation of the efficiency of different treatment technologies in the removal of various PPCPs from the wastewater and their sustainable management in the aquatic resources in Eastern Cape, South Africa. For the lipophilic organochlorine pesticides (OCPs), the limits of detection (LODs) of the tested congeners varied from 0.04 ng/g (α-BHC) to 0.49 ng/g (endosulfan sulfate) and the limits of quantification ranging from 0.22 ng/g (aldrin) to 2.17 ng/g (δ-BHC).
- Full Text:
- Date Issued: 2017
- Authors: Ademoyegun, Olufemi Temitope
- Date: 2017
- Subjects: Emerging contaminants in water -- South Africa -- Eastern Cape Water treatment plants -- Waste disposal -- South Africa -- Eastern Cape Organic compounds -- Environmental aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2922 , vital:28138
- Description: Emerging organic contaminants (EOCs) have been the focus of global environmental research for over three decades. EOCs have caused widespread concern due to their extensive use. As EOCs were designed to correct, enhance or protect a specific physiological, their target effects in humans and/or farm stocks are relatively well known and documented. However, there is limited knowledge about their unintended effects in the environment. To address the occurrence, distribution and fate of EOCs in the environment, efficient and reliable analytical methods are needed. The relatively low concentration, high polarity, and thermal lability of some EOCs, together with their interaction with complex environmental matrices, make their analysis challenging. Sample preparation followed by GC or HPLC separation and mass spectrometry (MS) detection has become the standard approach for evaluating EOCs in environmental samples. Physicochemical properties of EOCs range from highly water-soluble (hydrophylic) to highly water-insoluble (hydrophobic). Two groups of these EOCs were considered for study in this work. Pharmaceutical and personal care products (PPCPs) were comprehensively studied in five wastewater treatment plants and their receiving watersheds in Amathole districts in Eastern C ape, South Africa. PPCPs have been widely reported in wastewater influents, effluents, receiving rivers and biosolids, but reports of their occurrence in all these matrixes have been limited by the difficulty of analysis. Therefore, a comprehensive validation of methods was carried out on the influents, effluents, sludge and soil from the irrigated golf course where the effluent of one of the study sites was being used for over three decades now for irrigation. In all, thirteen PPCPs from five therapeutic groups were selected for study in this work because of their administering rate and availability of analytical instrument. Good limit of detection (LOD) and limit of quantification (LOQ) were achieved for the method used. The LOD for the aqueous Three different technologies were employed for the treatment of wastewater in the five selected wastewater treatment plants (WWTPs) and study was carried out to evaluate their ability to eliminate the selected compounds from the influents to the effluents using statistical analysis (ANOVA) at p<0.05 on the percentage removal rate across the three plants. The results had shown eight of the compounds having no significant difference among the treatment operations, whereas the remaining five compounds varied significantly among the treatment technologies under investigation. Principal component analysis was performed on the concentration of PPCPs, their removal rate and also on the physicochemical and treatment operation parameters. Hydraulic retention time (HRT) had correlation coefficient, r = 0.90 with the concentration of PPCPs and removal rates. Furthermore, occurrences, seasonal variation, mean concentration distribution pattern of the compounds, and temporal evaluation of the mean concentration of the pharmaceutical compounds in the five WWTPs during one year of sampling were considered. The results revealed that five products which were diclofenac, ibuprofen, paracetamol, triclosan and diethyl toluamide (DDET) were predominant among the PPCPs in all the WWTPs. The removal efficiency was highest in caffeine with 96 percent, and the lowest was obtained with carbamazepine (4 percent). Risk quotient of the concentration of PPCPs in the effluents and receiving waters was determined to assess their chronic toxicity at three trophic levels: fish, algae and matrixes studied ranged from 0.01 μg/L to 0.25 μg/L, and the LOQ from 0.02 μg/L to 0.78 μg/L. In the solid matrixes, LOD varied from 0.01 ng/g to 0.65 ng/g, and the LOQ between 0.08 ng/g and 5.17 ng/g. Better recovery efficiency was obtained with this mixture of solvents, acetone: dichloromethane (1:1), for the recovery of the five therapeutic groups in the solid matrixes using ultrasonication- assisted techniques. The results show percentage recovery values ranging from 68.8 percent to 107.5 percent diaphian. According to the environmental risk assessment results, ibuprofen and triclosan were found to be the most critical compounds due to their high risk quotient values. These findings will, therefore, help in the future evaluation of the efficiency of different treatment technologies in the removal of various PPCPs from the wastewater and their sustainable management in the aquatic resources in Eastern Cape, South Africa. For the lipophilic organochlorine pesticides (OCPs), the limits of detection (LODs) of the tested congeners varied from 0.04 ng/g (α-BHC) to 0.49 ng/g (endosulfan sulfate) and the limits of quantification ranging from 0.22 ng/g (aldrin) to 2.17 ng/g (δ-BHC).
- Full Text:
- Date Issued: 2017
The design of an international wool exchange for Port Elizabeth
- Authors: Bothma, Ashley Andre
- Date: 2016
- Subjects: Historic sites -- South Africa -- Port Elizabeth Historic buildings -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MArch
- Identifier: http://hdl.handle.net/10948/38852 , vital:35007
- Description: Due to the growth increase in the wool industry in South Africa and the industry's lack of public activity that the existing South Africa (S.A) wool exchange exudes, the opportunity for a new type of wool exchange presents itself. the advantages in technology have evolved in many an industry and the same can be for the wool industry. the existing S.A. wool exchange fails to comfortably meet the needs of the industry with regards to technology. the creation of international wool exchange will provide a platform to boost the industry and incorporate the use of current technology to improve on the process involved within the program. BKB. Ltd have expressed a similar interest in the development of an international wool exchange but have requested the use of an abounded heritage building in an attempt at a sustainable future through re-use.
- Full Text:
- Date Issued: 2016
- Authors: Bothma, Ashley Andre
- Date: 2016
- Subjects: Historic sites -- South Africa -- Port Elizabeth Historic buildings -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MArch
- Identifier: http://hdl.handle.net/10948/38852 , vital:35007
- Description: Due to the growth increase in the wool industry in South Africa and the industry's lack of public activity that the existing South Africa (S.A) wool exchange exudes, the opportunity for a new type of wool exchange presents itself. the advantages in technology have evolved in many an industry and the same can be for the wool industry. the existing S.A. wool exchange fails to comfortably meet the needs of the industry with regards to technology. the creation of international wool exchange will provide a platform to boost the industry and incorporate the use of current technology to improve on the process involved within the program. BKB. Ltd have expressed a similar interest in the development of an international wool exchange but have requested the use of an abounded heritage building in an attempt at a sustainable future through re-use.
- Full Text:
- Date Issued: 2016
An assessment of e-procurement in the Eastern Cape provincial government
- Myataza, Nosiphendule Mlamli
- Authors: Myataza, Nosiphendule Mlamli
- Date: 2015
- Subjects: Government purchasing -- South Africa -- Eastern Cape Electronic commerce -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Public Administration)
- Identifier: http://hdl.handle.net/10353/1601 , vital:27483
- Description: Public procurement is the government activity most vulnerable to corruption. Lack of transparency and accountability are recognised as a major threat to integrity in public procurement. Repeated findings by the Auditor- General(SA) on poor document management and lack of compliance with the Public Finance Management Act ( No1 of 1999) by the SCM units in departments of the Eastern Cape Provincial Administration necessitates the use of e-procurement for purposes of accountability and proper documentation of transactions. The study assessed the current status of e-procurement in the Eastern Cape Provincial government. This entailed an overview of IFMS, identifying its implementation and shortcomings. Also reviewed was implementation of the Logistical Information System ( LOGIS) in the Eastern Cape Provincial Administration (Department of Health) as its e-procurement platform, as well as e-procurement at the Department of Social development and Special Programmes .The status of government suppliers’ internet connectivity was also assessed.
- Full Text:
- Date Issued: 2015
- Authors: Myataza, Nosiphendule Mlamli
- Date: 2015
- Subjects: Government purchasing -- South Africa -- Eastern Cape Electronic commerce -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Public Administration)
- Identifier: http://hdl.handle.net/10353/1601 , vital:27483
- Description: Public procurement is the government activity most vulnerable to corruption. Lack of transparency and accountability are recognised as a major threat to integrity in public procurement. Repeated findings by the Auditor- General(SA) on poor document management and lack of compliance with the Public Finance Management Act ( No1 of 1999) by the SCM units in departments of the Eastern Cape Provincial Administration necessitates the use of e-procurement for purposes of accountability and proper documentation of transactions. The study assessed the current status of e-procurement in the Eastern Cape Provincial government. This entailed an overview of IFMS, identifying its implementation and shortcomings. Also reviewed was implementation of the Logistical Information System ( LOGIS) in the Eastern Cape Provincial Administration (Department of Health) as its e-procurement platform, as well as e-procurement at the Department of Social development and Special Programmes .The status of government suppliers’ internet connectivity was also assessed.
- Full Text:
- Date Issued: 2015
Water resources availability in the Caledon River basin : past, present and future
- Authors: Mohobane, Thabiso
- Date: 2015
- Subjects: Water-supply -- South Africa -- Caledon River Valley , Climatic changes -- South Africa -- Caledon River Valley , Hydrologic models -- South Africa -- Caledon River Valley , Precipitation forecasting -- South Africa -- Caledon River Valley , Water-supply -- Forecasting , Runoff -- Mathematical models , Evapotranspiration -- South Africa -- Caledon River Valley
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6055 , http://hdl.handle.net/10962/d1019802
- Description: The Caledon River Basin is located on one of the most water-scarce region on the African continent. The water resources of the Caledon River Basin play a pivotal role in socio-economic activities in both Lesotho and South Africa but the basin experiences recurrent severe droughts and frequent water shortages. The Caledon River is mostly used for commercial and subsistence agriculture, industrial and domestic supply. The resources are also important beyond the basin’s boundaries as the water is transferred to the nearby Modder River. The Caledon River is also a significant tributary to the Orange-Senqu Basin, which is shared by five southern African countries. However, the water resources in the basin are under continuous threat as a result of rapidly growing population, economic growth as well as changing climate, amongst others. It is therefore important that the hydrological regime and water resources of the basin are thoroughly evaluated and assessed so that they can be sustainably managed and utilised for maximum economic benefits. Climate change has been identified by the international community as one of the most prominent threats to peace, food security and livelihood and southern Africa as among the most vulnerable regions of the world. Water resources are perceived as a natural resource which will be affected the most by the changing climate conditions. Global warming is expected to bring more severe, prolonged droughts and exacerbate water shortages in this region. The current study is mainly focused on investigating the impacts of climate change on the water resources of the Caledon River Basin. The main objectives of the current study included assessing the past and current hydrological characteristics of the Caledon River Basin under current state of the physical environment, observed climate conditions and estimated water use; detecting any changes in the future rainfall and evaporative demands relative to present conditions and evaluating the impacts of climate on the basin’s hydrological regime and water resources availability for the future climate scenario, 2046-2065. To achieve these objectives the study used observed hydrological, meteorological data sets and the basin’s physical characteristics to establish parameters of the Pitman and WEAP hydrological models. Hydrological modelling is an integral part of hydrological investigations and evaluations. The various sources of uncertainties in the outputs of the climate and hydrological models were identified and quantified, as an integral part of the whole exercise. The 2-step approach of the uncertainty version of the model was used to estimate a range of parameters yielding behavioural natural flow ensembles. This approach uses the regional and local hydrological signals to constrain the model parameter ranges. The estimated parameters were also employed to guide the calibration process of the Water Evaluation And Planning (WEAP) model. The two models incorporated the estimated water uses within the basin to establish the present day flow simulations and they were found to sufficiently simulate the present day flows, as compared to the observed flows. There is an indication therefore, that WEAP can be successfully applied in other regions for hydrological investigations. Possible changes in future climate regime of the basin were evaluated by analysing downscaled temperature and rainfall outputs from a set of 9 climate models. The predictions are based on the A2 greenhouse gases emission scenario which assumes a continuous increase in emission rates. While the climate models agree that temperature, and hence, evapotranspiration will increase in the future, they demonstrate significant disagreement on whether rainfall will decrease or increase and by how much. The disagreement of the GCMs on projected future rainfall constitutes a major uncertainty in the prediction of water resources availability of the basin. This is to the extent that according to 7 out of 9 climate models used, the stream flow in four sub-basins (D21E, D22B, D23D and D23F) in the Caledon River Basin is projected to decrease below the present day flows, while two models (IPSL and MIUB) consistently project enhanced water resource availability in the basin in the future. The differences in the GCM projections highlight the margin of uncertainty involved predicting the future status of water resources in the basin. Such uncertainty should not be ignored and these results can be useful in aiding decision-makers to develop policies that are robust and that encompass all possibilities. In an attempt to reduce the known uncertainties, the study recommends upgrading of the hydrological monitoring network within the Caledon River Basin to facilitate improved hydrological evaluation and management. It also suggests the use of updated climate change data from the newest generation climate models, as well as integrating the findings of the current research into water resources decision making process.
- Full Text:
- Date Issued: 2015
- Authors: Mohobane, Thabiso
- Date: 2015
- Subjects: Water-supply -- South Africa -- Caledon River Valley , Climatic changes -- South Africa -- Caledon River Valley , Hydrologic models -- South Africa -- Caledon River Valley , Precipitation forecasting -- South Africa -- Caledon River Valley , Water-supply -- Forecasting , Runoff -- Mathematical models , Evapotranspiration -- South Africa -- Caledon River Valley
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6055 , http://hdl.handle.net/10962/d1019802
- Description: The Caledon River Basin is located on one of the most water-scarce region on the African continent. The water resources of the Caledon River Basin play a pivotal role in socio-economic activities in both Lesotho and South Africa but the basin experiences recurrent severe droughts and frequent water shortages. The Caledon River is mostly used for commercial and subsistence agriculture, industrial and domestic supply. The resources are also important beyond the basin’s boundaries as the water is transferred to the nearby Modder River. The Caledon River is also a significant tributary to the Orange-Senqu Basin, which is shared by five southern African countries. However, the water resources in the basin are under continuous threat as a result of rapidly growing population, economic growth as well as changing climate, amongst others. It is therefore important that the hydrological regime and water resources of the basin are thoroughly evaluated and assessed so that they can be sustainably managed and utilised for maximum economic benefits. Climate change has been identified by the international community as one of the most prominent threats to peace, food security and livelihood and southern Africa as among the most vulnerable regions of the world. Water resources are perceived as a natural resource which will be affected the most by the changing climate conditions. Global warming is expected to bring more severe, prolonged droughts and exacerbate water shortages in this region. The current study is mainly focused on investigating the impacts of climate change on the water resources of the Caledon River Basin. The main objectives of the current study included assessing the past and current hydrological characteristics of the Caledon River Basin under current state of the physical environment, observed climate conditions and estimated water use; detecting any changes in the future rainfall and evaporative demands relative to present conditions and evaluating the impacts of climate on the basin’s hydrological regime and water resources availability for the future climate scenario, 2046-2065. To achieve these objectives the study used observed hydrological, meteorological data sets and the basin’s physical characteristics to establish parameters of the Pitman and WEAP hydrological models. Hydrological modelling is an integral part of hydrological investigations and evaluations. The various sources of uncertainties in the outputs of the climate and hydrological models were identified and quantified, as an integral part of the whole exercise. The 2-step approach of the uncertainty version of the model was used to estimate a range of parameters yielding behavioural natural flow ensembles. This approach uses the regional and local hydrological signals to constrain the model parameter ranges. The estimated parameters were also employed to guide the calibration process of the Water Evaluation And Planning (WEAP) model. The two models incorporated the estimated water uses within the basin to establish the present day flow simulations and they were found to sufficiently simulate the present day flows, as compared to the observed flows. There is an indication therefore, that WEAP can be successfully applied in other regions for hydrological investigations. Possible changes in future climate regime of the basin were evaluated by analysing downscaled temperature and rainfall outputs from a set of 9 climate models. The predictions are based on the A2 greenhouse gases emission scenario which assumes a continuous increase in emission rates. While the climate models agree that temperature, and hence, evapotranspiration will increase in the future, they demonstrate significant disagreement on whether rainfall will decrease or increase and by how much. The disagreement of the GCMs on projected future rainfall constitutes a major uncertainty in the prediction of water resources availability of the basin. This is to the extent that according to 7 out of 9 climate models used, the stream flow in four sub-basins (D21E, D22B, D23D and D23F) in the Caledon River Basin is projected to decrease below the present day flows, while two models (IPSL and MIUB) consistently project enhanced water resource availability in the basin in the future. The differences in the GCM projections highlight the margin of uncertainty involved predicting the future status of water resources in the basin. Such uncertainty should not be ignored and these results can be useful in aiding decision-makers to develop policies that are robust and that encompass all possibilities. In an attempt to reduce the known uncertainties, the study recommends upgrading of the hydrological monitoring network within the Caledon River Basin to facilitate improved hydrological evaluation and management. It also suggests the use of updated climate change data from the newest generation climate models, as well as integrating the findings of the current research into water resources decision making process.
- Full Text:
- Date Issued: 2015
"Abject dictatorship of the flesh" : corporeality in the fiction of Patrick White
- Authors: Grogan, Bridget Meredith
- Date: 2013
- Subjects: White, Patrick, 1912-1990 -- Criticism and interpretation Human body in literature Dualism in literature Human body -- Social aspects Body image -- Social aspects Australian fiction -- 20th century -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2166 , http://hdl.handle.net/10962/d1001554
- Description: Thesis embargoed for an indefinite period - full text not available
- Full Text: false
- Date Issued: 2013
- Authors: Grogan, Bridget Meredith
- Date: 2013
- Subjects: White, Patrick, 1912-1990 -- Criticism and interpretation Human body in literature Dualism in literature Human body -- Social aspects Body image -- Social aspects Australian fiction -- 20th century -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2166 , http://hdl.handle.net/10962/d1001554
- Description: Thesis embargoed for an indefinite period - full text not available
- Full Text: false
- Date Issued: 2013
Quantification of the cross-sectoral impacts of waterweeds and their control in Ghana
- Authors: Akpabey, Felix Jerry
- Date: 2012
- Subjects: Water hyacinth -- Control -- Environmental aspects -- Ghana Alien plants -- Research -- Ghana Introduced organisms Economic development -- Social aspects -- Research -- Ghana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5748 , http://hdl.handle.net/10962/d1005435
- Description: The Akosombo Dam on the Volta River in Ghana was built in 1963 to provide cheap energy to fuel industry and to accelerate the economic growth of the country. It provides hydroelectric power, enhanced fishing and water transportation upstream, and improved opportunities for irrigated farming, especially in the lower reaches, and their attendant economic multiplier effects. A few years after the construction of this major dam, a rapid expansion of industrialization took place in Ghana. This brought about an exponential increase in demand for more electrical power. This led to the construction of a smaller dam at Akuse, downstream of the Akosomho Dam in 1981 and the formation of a headpond at Kpong. The impoundment of the river at the two sites (Akosombo and Kpong) caused an alteration in the existing ecological and biophysical processes in the river basin, including a slowing of the flow of the river, upstream and downstream. Changes in the natural processes, such as a reduction in the flow of the river and an increase in nutrient status of the water, resulted in an invasion of aquatic weeds, increasing the density of aquatic snails (intermediate hosts of schistosomiasis), silting and closure of the estuary, as well as other more subtle effects. The invasion of the river's main course and the dams by aquatic plants led to a corresponding reduction of navigable water both upstream and downstream. The aim of this thesis was to quantify the impact and control of waterweeds, especially water hyacinth, Eichhornia crassipes (Mart) Solms-Laubach (Pontederiaceae), in Ghana. A floral survey on the Kpong Headpond recorded 49 emergent, 12 free floating and I submerged aquatic plant species, many of which were indigenous, but the exotic or introduced water hyacinth was recorded at most of the sampling sites, and was the most abundant and had the biggest impact on the utilization of the water resource. Mats of water hyacinth served as substrates for other, indigenous species to grow out into the main channel of the headpond, including the intake point of the Kpong head works of the Ghana Water Company Limited (GWCL) and landing sites for boats. These mats resulted in a reduction of the fish (fin and shell) harvest, reducing the annual production to far below demand. Water hyacinth was also shown to have severe health implications. A survey of the Ministry of Health records showed that the prevalence of both urinary and intestinal schistosomiasis had risen significantly over time as the abundance of waterweeds, most notably water hyacinth, increased, and ranged between 70% and 75% but up to 100% in some lakeside communities. Based on the work done by an NGO on board the medical boat ("Onipa Nua "), losses in terms of money due to the effect on health of the aquatic weed infestations on the Volta River in 2006 amounted to US$ 620,000. Economic losses due to invasive alien aquatic weeds were also calculated on the Oti River Arm of Lake Volta. It was estimated that about US$2.3 million per annum would be lost to the Volta Lake Transport Company and individual boat transport operators if this section of the river were 100% covered by aquatic weeds (water hyacinth and Salvinia molesta D.S. Mitchell (Salviniaceae)). It was also estimated that US$327,038 was spent annually in monitoring and managing the weeds in the Oti River. Control interventions for aquatic weeds have been implemented in river systems in Ghana. The biological control agents Neochetina bruchi Hustache (Coleoptera, Curculionidae) and Neochetina eichhorniae Warner (Coleoptera, Curculionidae) have been used on water hyacinth infestations in the Oti River Arm of Lake Volta, the Tano River and the Lagoon complex in the south-western part of the country. Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) has been used to control salvinia, and Neohydronomous affinis Hustache (Coleoptera: Curculionidae) to control water lettuce, Pistia stratiotes Lilmaeus (Araceae) in the Tano River and Lagoon complex. Although these projects have been regarded as successful, they have relied on research from elsewhere in the world and no postrelease quantification has been conducted. In evaluating the impact of the biological control agents Neochetina bruchi and Neochetina eichhorniae weevils on water hyacinth infestations in the Tano River, fresh adult feeding scars were recorded as well as the numbers of adult weevils on each water hyacinth plant sampled at six sites. Despite being released in 1994, weevil numbers and resultant damage to plants in the Tano Lagoon was low in comparison to other regions of the world where these agents have been used. The main reason for this is that this lagoon floods seasonally, washing weevil-infested plants out to sea. Water hyacinth then re-infests the lagoon from seed and the weevil populations are low. To resolve this situation, two courses of action are proposed. The first is to mass rear the weevils along the shore of the lagoon and release them when the first seedlings recruit. The second proposal is that additional agents that have shorter lifecycies and are more mobile than the weevils should be released. To this end, the water hyacinth mirid, Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae) was imported from South Africa and released onto the Tano Lagoon in 2009. Retrospective laboratory host specificity trials were conducted on Neachetina eichharniae and Neachetina bruchi weevils 15 years after their release into Ghana to see if any variation in their host ranges had occurred. Considerable damage was inflicted on the E. crassipes leaves by the Neachetina weevils, while little feeding damage was recorded on both Heteranthera callifalia Kunth. (Pontederiaceae) and Eichharnia natans (P.Beauv.) Solms (Pontederiaceae). All the weevils introduced on H callifalia and E. natans died after the first week. This study served to confirm the host specificity and thereby the safety of these agents. Invasive alien aquatic macrophytes have negative impacts on the environment and economy of Ghana. The control of these weeds is essential to socioeconomic development and improved human health standards in riparian communities. Biological control offers a safe and sustainable control option, but requires diligent implementation. However, aquatic weed invasion is more typically a result of the anthropogenically induced eutrophication of water bodies, and this is the main issue that has to be addressed.
- Full Text:
- Date Issued: 2012
- Authors: Akpabey, Felix Jerry
- Date: 2012
- Subjects: Water hyacinth -- Control -- Environmental aspects -- Ghana Alien plants -- Research -- Ghana Introduced organisms Economic development -- Social aspects -- Research -- Ghana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5748 , http://hdl.handle.net/10962/d1005435
- Description: The Akosombo Dam on the Volta River in Ghana was built in 1963 to provide cheap energy to fuel industry and to accelerate the economic growth of the country. It provides hydroelectric power, enhanced fishing and water transportation upstream, and improved opportunities for irrigated farming, especially in the lower reaches, and their attendant economic multiplier effects. A few years after the construction of this major dam, a rapid expansion of industrialization took place in Ghana. This brought about an exponential increase in demand for more electrical power. This led to the construction of a smaller dam at Akuse, downstream of the Akosomho Dam in 1981 and the formation of a headpond at Kpong. The impoundment of the river at the two sites (Akosombo and Kpong) caused an alteration in the existing ecological and biophysical processes in the river basin, including a slowing of the flow of the river, upstream and downstream. Changes in the natural processes, such as a reduction in the flow of the river and an increase in nutrient status of the water, resulted in an invasion of aquatic weeds, increasing the density of aquatic snails (intermediate hosts of schistosomiasis), silting and closure of the estuary, as well as other more subtle effects. The invasion of the river's main course and the dams by aquatic plants led to a corresponding reduction of navigable water both upstream and downstream. The aim of this thesis was to quantify the impact and control of waterweeds, especially water hyacinth, Eichhornia crassipes (Mart) Solms-Laubach (Pontederiaceae), in Ghana. A floral survey on the Kpong Headpond recorded 49 emergent, 12 free floating and I submerged aquatic plant species, many of which were indigenous, but the exotic or introduced water hyacinth was recorded at most of the sampling sites, and was the most abundant and had the biggest impact on the utilization of the water resource. Mats of water hyacinth served as substrates for other, indigenous species to grow out into the main channel of the headpond, including the intake point of the Kpong head works of the Ghana Water Company Limited (GWCL) and landing sites for boats. These mats resulted in a reduction of the fish (fin and shell) harvest, reducing the annual production to far below demand. Water hyacinth was also shown to have severe health implications. A survey of the Ministry of Health records showed that the prevalence of both urinary and intestinal schistosomiasis had risen significantly over time as the abundance of waterweeds, most notably water hyacinth, increased, and ranged between 70% and 75% but up to 100% in some lakeside communities. Based on the work done by an NGO on board the medical boat ("Onipa Nua "), losses in terms of money due to the effect on health of the aquatic weed infestations on the Volta River in 2006 amounted to US$ 620,000. Economic losses due to invasive alien aquatic weeds were also calculated on the Oti River Arm of Lake Volta. It was estimated that about US$2.3 million per annum would be lost to the Volta Lake Transport Company and individual boat transport operators if this section of the river were 100% covered by aquatic weeds (water hyacinth and Salvinia molesta D.S. Mitchell (Salviniaceae)). It was also estimated that US$327,038 was spent annually in monitoring and managing the weeds in the Oti River. Control interventions for aquatic weeds have been implemented in river systems in Ghana. The biological control agents Neochetina bruchi Hustache (Coleoptera, Curculionidae) and Neochetina eichhorniae Warner (Coleoptera, Curculionidae) have been used on water hyacinth infestations in the Oti River Arm of Lake Volta, the Tano River and the Lagoon complex in the south-western part of the country. Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) has been used to control salvinia, and Neohydronomous affinis Hustache (Coleoptera: Curculionidae) to control water lettuce, Pistia stratiotes Lilmaeus (Araceae) in the Tano River and Lagoon complex. Although these projects have been regarded as successful, they have relied on research from elsewhere in the world and no postrelease quantification has been conducted. In evaluating the impact of the biological control agents Neochetina bruchi and Neochetina eichhorniae weevils on water hyacinth infestations in the Tano River, fresh adult feeding scars were recorded as well as the numbers of adult weevils on each water hyacinth plant sampled at six sites. Despite being released in 1994, weevil numbers and resultant damage to plants in the Tano Lagoon was low in comparison to other regions of the world where these agents have been used. The main reason for this is that this lagoon floods seasonally, washing weevil-infested plants out to sea. Water hyacinth then re-infests the lagoon from seed and the weevil populations are low. To resolve this situation, two courses of action are proposed. The first is to mass rear the weevils along the shore of the lagoon and release them when the first seedlings recruit. The second proposal is that additional agents that have shorter lifecycies and are more mobile than the weevils should be released. To this end, the water hyacinth mirid, Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae) was imported from South Africa and released onto the Tano Lagoon in 2009. Retrospective laboratory host specificity trials were conducted on Neachetina eichharniae and Neachetina bruchi weevils 15 years after their release into Ghana to see if any variation in their host ranges had occurred. Considerable damage was inflicted on the E. crassipes leaves by the Neachetina weevils, while little feeding damage was recorded on both Heteranthera callifalia Kunth. (Pontederiaceae) and Eichharnia natans (P.Beauv.) Solms (Pontederiaceae). All the weevils introduced on H callifalia and E. natans died after the first week. This study served to confirm the host specificity and thereby the safety of these agents. Invasive alien aquatic macrophytes have negative impacts on the environment and economy of Ghana. The control of these weeds is essential to socioeconomic development and improved human health standards in riparian communities. Biological control offers a safe and sustainable control option, but requires diligent implementation. However, aquatic weed invasion is more typically a result of the anthropogenically induced eutrophication of water bodies, and this is the main issue that has to be addressed.
- Full Text:
- Date Issued: 2012
Formulation and assessment of verapamil sustained release tablets
- Khamanga, Sandile Maswazi Malungelo
- Authors: Khamanga, Sandile Maswazi Malungelo
- Date: 2005
- Subjects: Verapamil , Tablets (Medicine) , Drugs -- Administration , Cardiovascular agents , Calcium -- Antagonists , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3869 , http://hdl.handle.net/10962/d1018236
- Description: The oral route of drug administration is most extensively used due to the obvious ease of administration. Verapamil hydrochloride is a WHO listed phenylalkylarnine, L-type calcium channel antagonist that is mainly indicated for cardiovascular disorders such as angina pectoris, supraventricular tachycardia and hypertension. Due to its relatively short half-life of approximately 4.0 hours, the formulation of a sustained-release dosage form is useful to improve patient compliance and to achieve predictable and optimized therapeutic plasma concentrations. Direct compression and wet granulation were initially used as methods for tablet manufacture. The direct compression method of manufacture produced tablets that exhibited formulation and manufacturing difficulties. Mini-tablets containing veraparnil hydrochloride were then prepared by wet granulation using Surelease® E-7-19010.and Eudragit® NE 30D as the granulating agents after which the granules were incorporated with an hydrophilic matrix material, Carbopol® 974P NF. Granule and powder blends were evaluated using the angle of repose, loose and tapped bulk density, Can's compressibility index, Hausner's ratio and drug content. Granules with good flow properties and satisfactory compressibility were used for further studies. Tablets were subjected to thickness, diameter and weight variation tests, crushing strength, tensile strength, friability and content uniformity studies. Tablets that showed acceptable pharmaco-technical properties were selected for further analysis. Drug content uniformity and dissolution release rates were determined using a validated isocratic HPLC method. Initially, USP apparatus 1 and 3 dissolution apparatus were used to determine in-vitro drug release rates from the formulations over a 22-hour period. USP apparatus 3 was finally selected as it offers the advantages of mimicking, in part, the changes in the physicochemical environment experienced by products in the gastro-intestinal tract. Differences in release rates between the test formulations and a commercially available product, Isoptin® SR were observed at different pH's using USP apparatus 1. The release of veraparnil hydrochloride from matrix tablets was pH dependent and was markedly reduced at higher pH values. This may be due, in part, to the poor solubility of veraparnil hydrochloride at these pH values and also the possible interaction of verapamil hydrochloride with anionic polymers used in these formulations. Swelling and erosion behaviour of the tablets were evaluated and differences in behaviour were observed which may be attributed to the physico-chemical characteristics of the polymers used in this study. In-vitro dissolution profiles were characterized by the difference (j1) and similarity factor (j2) and also by a new similarity factor, Sct. In addition, the mechanism of drug release from these dosage forms was mainly evaluated using the Korsmeyer-Peppas model and the kinetics of drug release assessed using other models, including Zero order, First order, Higuchi, HixsonCrowell, Weibull and the Baker-Lonsdale model. Dissolution kinetics were best described by application of the Weibull model, and the Korsmeyer-Peppas model. The release exponent, n, confirmed that drug release from these dosage forms was due to the mixed effects of diffusion and swelling and therefore, anomalous release kinetics are predominant. In conclusion, two test batches were found to be comparable to the reference product Isoptin® SR with respect to their in-vitro release profiles.
- Full Text:
- Date Issued: 2005
- Authors: Khamanga, Sandile Maswazi Malungelo
- Date: 2005
- Subjects: Verapamil , Tablets (Medicine) , Drugs -- Administration , Cardiovascular agents , Calcium -- Antagonists , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3869 , http://hdl.handle.net/10962/d1018236
- Description: The oral route of drug administration is most extensively used due to the obvious ease of administration. Verapamil hydrochloride is a WHO listed phenylalkylarnine, L-type calcium channel antagonist that is mainly indicated for cardiovascular disorders such as angina pectoris, supraventricular tachycardia and hypertension. Due to its relatively short half-life of approximately 4.0 hours, the formulation of a sustained-release dosage form is useful to improve patient compliance and to achieve predictable and optimized therapeutic plasma concentrations. Direct compression and wet granulation were initially used as methods for tablet manufacture. The direct compression method of manufacture produced tablets that exhibited formulation and manufacturing difficulties. Mini-tablets containing veraparnil hydrochloride were then prepared by wet granulation using Surelease® E-7-19010.and Eudragit® NE 30D as the granulating agents after which the granules were incorporated with an hydrophilic matrix material, Carbopol® 974P NF. Granule and powder blends were evaluated using the angle of repose, loose and tapped bulk density, Can's compressibility index, Hausner's ratio and drug content. Granules with good flow properties and satisfactory compressibility were used for further studies. Tablets were subjected to thickness, diameter and weight variation tests, crushing strength, tensile strength, friability and content uniformity studies. Tablets that showed acceptable pharmaco-technical properties were selected for further analysis. Drug content uniformity and dissolution release rates were determined using a validated isocratic HPLC method. Initially, USP apparatus 1 and 3 dissolution apparatus were used to determine in-vitro drug release rates from the formulations over a 22-hour period. USP apparatus 3 was finally selected as it offers the advantages of mimicking, in part, the changes in the physicochemical environment experienced by products in the gastro-intestinal tract. Differences in release rates between the test formulations and a commercially available product, Isoptin® SR were observed at different pH's using USP apparatus 1. The release of veraparnil hydrochloride from matrix tablets was pH dependent and was markedly reduced at higher pH values. This may be due, in part, to the poor solubility of veraparnil hydrochloride at these pH values and also the possible interaction of verapamil hydrochloride with anionic polymers used in these formulations. Swelling and erosion behaviour of the tablets were evaluated and differences in behaviour were observed which may be attributed to the physico-chemical characteristics of the polymers used in this study. In-vitro dissolution profiles were characterized by the difference (j1) and similarity factor (j2) and also by a new similarity factor, Sct. In addition, the mechanism of drug release from these dosage forms was mainly evaluated using the Korsmeyer-Peppas model and the kinetics of drug release assessed using other models, including Zero order, First order, Higuchi, HixsonCrowell, Weibull and the Baker-Lonsdale model. Dissolution kinetics were best described by application of the Weibull model, and the Korsmeyer-Peppas model. The release exponent, n, confirmed that drug release from these dosage forms was due to the mixed effects of diffusion and swelling and therefore, anomalous release kinetics are predominant. In conclusion, two test batches were found to be comparable to the reference product Isoptin® SR with respect to their in-vitro release profiles.
- Full Text:
- Date Issued: 2005
Rainfall variability in Southern Africa, its influences on streamflow variations and its relationships with climatic variations
- Authors: Valimba, Patrick
- Date: 2005
- Subjects: Rain and rainfall -- Africa, Southern Climatic changes -- Africa, Southern Streamflow -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6030 , http://hdl.handle.net/10962/d1006159
- Description: Hydrological variability involving rainfall and streamflows in southern Africa have been often studied separately or have used cumulative rainfall and streamflow indices. The main objective of this study was to investigate spatio-temporal variations of rainfall, their influences on streamflows and their relationships with climatic variations with emphasis on indices that characterise the hydrological extremes, floods and droughts. It was found that 60-70% of the time when it rains, daily rainfalls are below their long-term averages and daily amounts below 10 mm are the most frequent in southern Africa. Spatially, climatologies of rainfall sub-divided the southern African subcontinent into the dry western/southwestern part and the “humid” eastern and northern part. The daily amounts below 20 mm contribute significantly to annual rainfall amounts in the dry part while all types of daily rainfall exceeding 1 mm have comparable contributions in the humid part. The climatologies indicated the highest likelihood of experiencing intense daily events during the core of the wet seasons with the highest frequencies in central Mozambique and the southern highlands of Tanzania. Interannual variations of rainfall indicated that significant changes had occurred between the late-1940s and early-1980s, particularly in the 1970s. The changes in rainfall were more evident in the number of daily rainfall events than in rainfall amounts, led generally to increasing early summer and decreased late summer rainfall. It was also found that intra-seasonal dry day sequences were an important parameter in the definition of a rainy season’s onset and end in southern Africa apart from rainfall amounts. Interannual variations of the rainy season characteristics (onset, end, duration) followed the variations of rainfall amounts and number of events. The duration of the rainy season was affected by the onset (Tanzania), onset or end (tropical southern Africa - southwestern highlands of Tanzania, Zambia, northern Zimbabwe and central Mozambique) and end (the remaing part of southern Africa). Flow duration curves (FDCs) identified three types of rivers (ephemeral, seasonal and perennial) in southern Africa with ephemeral rivers found mainly in the dry western part of the region. Seasonal streamflow patterns followed those of rainfall while interannual streamflow variations indicated significant changes of mean flows with little evidences of high and low flow regime changes except in Namibia and some parts of northern Zimbabwe. It was, however, not possible to provide strong links between the identified changes in streamflows and those in rainfall. Regarding the influences of climate variability on hydrological variability in southern Africa, rainfall variations in southern Africa were found to be influenced strongly by ENSO and SST in the tropical Indian ocean and moderately by SST in the south Madagascar basin. The influence of ENSO was consistent for all types of daily rainfall and peaks for the light and moderate (< 20 mm) events in the southern part and for the intense events in the northern part. SST in the tropical Indian ocean influence the light and moderate events while SST close to the region influence the heavy events. However, the relationships experienced significant changes in the mid-1950s and in the 1970s. The former changes led to improved associations while the latter deteriorated or reversed the relationships. The influences of climatic variables on streamflows and rainy season characteristics were inferred from the rainfall-streamflow and rainfall-climatic variables relationships.
- Full Text:
- Date Issued: 2005
- Authors: Valimba, Patrick
- Date: 2005
- Subjects: Rain and rainfall -- Africa, Southern Climatic changes -- Africa, Southern Streamflow -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6030 , http://hdl.handle.net/10962/d1006159
- Description: Hydrological variability involving rainfall and streamflows in southern Africa have been often studied separately or have used cumulative rainfall and streamflow indices. The main objective of this study was to investigate spatio-temporal variations of rainfall, their influences on streamflows and their relationships with climatic variations with emphasis on indices that characterise the hydrological extremes, floods and droughts. It was found that 60-70% of the time when it rains, daily rainfalls are below their long-term averages and daily amounts below 10 mm are the most frequent in southern Africa. Spatially, climatologies of rainfall sub-divided the southern African subcontinent into the dry western/southwestern part and the “humid” eastern and northern part. The daily amounts below 20 mm contribute significantly to annual rainfall amounts in the dry part while all types of daily rainfall exceeding 1 mm have comparable contributions in the humid part. The climatologies indicated the highest likelihood of experiencing intense daily events during the core of the wet seasons with the highest frequencies in central Mozambique and the southern highlands of Tanzania. Interannual variations of rainfall indicated that significant changes had occurred between the late-1940s and early-1980s, particularly in the 1970s. The changes in rainfall were more evident in the number of daily rainfall events than in rainfall amounts, led generally to increasing early summer and decreased late summer rainfall. It was also found that intra-seasonal dry day sequences were an important parameter in the definition of a rainy season’s onset and end in southern Africa apart from rainfall amounts. Interannual variations of the rainy season characteristics (onset, end, duration) followed the variations of rainfall amounts and number of events. The duration of the rainy season was affected by the onset (Tanzania), onset or end (tropical southern Africa - southwestern highlands of Tanzania, Zambia, northern Zimbabwe and central Mozambique) and end (the remaing part of southern Africa). Flow duration curves (FDCs) identified three types of rivers (ephemeral, seasonal and perennial) in southern Africa with ephemeral rivers found mainly in the dry western part of the region. Seasonal streamflow patterns followed those of rainfall while interannual streamflow variations indicated significant changes of mean flows with little evidences of high and low flow regime changes except in Namibia and some parts of northern Zimbabwe. It was, however, not possible to provide strong links between the identified changes in streamflows and those in rainfall. Regarding the influences of climate variability on hydrological variability in southern Africa, rainfall variations in southern Africa were found to be influenced strongly by ENSO and SST in the tropical Indian ocean and moderately by SST in the south Madagascar basin. The influence of ENSO was consistent for all types of daily rainfall and peaks for the light and moderate (< 20 mm) events in the southern part and for the intense events in the northern part. SST in the tropical Indian ocean influence the light and moderate events while SST close to the region influence the heavy events. However, the relationships experienced significant changes in the mid-1950s and in the 1970s. The former changes led to improved associations while the latter deteriorated or reversed the relationships. The influences of climatic variables on streamflows and rainy season characteristics were inferred from the rainfall-streamflow and rainfall-climatic variables relationships.
- Full Text:
- Date Issued: 2005
Catalytic behaviour of metallophthalocyanines towards the detection of nitric oxide
- Authors: Vilakazi, Lea Sibulelo
- Date: 2002
- Subjects: Electrochemistry Nitric oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4418 , http://hdl.handle.net/10962/d1006852
- Description: Electrocatalytic reduction and oxidation of nitric oxide (NO) using cobalt phthalocyanine complexes have been studied and compared to vitamin B₁₂ and other metallophthalocyanine (MPc) complexes. Modifying a glassy carbon electrode with these complexes resulted in improved sensitivity of the electrode allowing detection of NO to 10⁻⁹ mol dm⁻³. The mechanisms of catalysis were studied. Electrocatalysis of NO involves coordination of NO to the MPc complex. Hence catalytic activity is affected by the nature of the metal center. However coordination of NO to the MPc complex has to be reversible to eliminate poisoning of the electrode. Though FePc gave the best sensitivity and lowered the reduction potential more than CoPc, the strong Fe-NO bond resulted in the poisoning of the electrode hence, rendering the electrode unstable. Rate constants for NO coordination to the MPc complexes were studied. These rates were smaller than the studied NO porphyrin coordination rates. Electrocatalytic reduction of NO using MPc complexes involves a transfer of an electron from the metal center to the NO ligand. Hence, substitution of electron-donating grohps on the cobalt pthalocyanine complex resulted in improved sensitivity and catalytic activity. A CoPc modified microelectrode (11μm) was used to monitor NO in human blood components and to detect NO in a rat brain. Detections of NO were also done in aqueous solutions in the presence of interfering species such as dopamine and serotonin. An interaction between NO and serotonin was observed.
- Full Text:
- Date Issued: 2002
- Authors: Vilakazi, Lea Sibulelo
- Date: 2002
- Subjects: Electrochemistry Nitric oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4418 , http://hdl.handle.net/10962/d1006852
- Description: Electrocatalytic reduction and oxidation of nitric oxide (NO) using cobalt phthalocyanine complexes have been studied and compared to vitamin B₁₂ and other metallophthalocyanine (MPc) complexes. Modifying a glassy carbon electrode with these complexes resulted in improved sensitivity of the electrode allowing detection of NO to 10⁻⁹ mol dm⁻³. The mechanisms of catalysis were studied. Electrocatalysis of NO involves coordination of NO to the MPc complex. Hence catalytic activity is affected by the nature of the metal center. However coordination of NO to the MPc complex has to be reversible to eliminate poisoning of the electrode. Though FePc gave the best sensitivity and lowered the reduction potential more than CoPc, the strong Fe-NO bond resulted in the poisoning of the electrode hence, rendering the electrode unstable. Rate constants for NO coordination to the MPc complexes were studied. These rates were smaller than the studied NO porphyrin coordination rates. Electrocatalytic reduction of NO using MPc complexes involves a transfer of an electron from the metal center to the NO ligand. Hence, substitution of electron-donating grohps on the cobalt pthalocyanine complex resulted in improved sensitivity and catalytic activity. A CoPc modified microelectrode (11μm) was used to monitor NO in human blood components and to detect NO in a rat brain. Detections of NO were also done in aqueous solutions in the presence of interfering species such as dopamine and serotonin. An interaction between NO and serotonin was observed.
- Full Text:
- Date Issued: 2002
An examination of the factors influencing the spatial distribution of the Indian communities in Grahamstown, King William's town, Queenstown and Uitenhage from 1880 to 1991
- Authors: Dullabh, Neela
- Date: 1995
- Subjects: East Indians -- South Africa -- Social conditions East Indians -- South Africa -- Economic conditions Apartheid -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4831 , http://hdl.handle.net/10962/d1005506
- Description: This study examines the factors influencing the spatial distribution of the Indian communities of Grahamstown, King William's Town, Queenstown and Uitenhage from 1880 to 1991. Primary sources of information were used to determine both the spatial distribution of the four communities and the factors influencing the distribution found. These primary sources included the use of directories, municipal and archival sources of information, interviews as well the work of various authors. The study found that the spatial distribution of Indians in the four study areas were similar with the Indians occupying residential and commercial premises in the central areas of the urban centres. After 1980 there was a substantial movement to other areas. Prior to 1950 the municipalities played an important role in influencing spatial distribution. However, after the introduction of the Group Areas Act, the govennment controlled Indian spatial distribution. Thus the Group Areas Act was the most important factor affecting Indian spatial distribution. Indians in small urban centres in the Cape Province were segregated and their spatial distribution was controlled both prior to and after 1950. Anti-Indian legislation and restrictions were the main factors influencing Indian spatial distribution.
- Full Text:
- Date Issued: 1995
- Authors: Dullabh, Neela
- Date: 1995
- Subjects: East Indians -- South Africa -- Social conditions East Indians -- South Africa -- Economic conditions Apartheid -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4831 , http://hdl.handle.net/10962/d1005506
- Description: This study examines the factors influencing the spatial distribution of the Indian communities of Grahamstown, King William's Town, Queenstown and Uitenhage from 1880 to 1991. Primary sources of information were used to determine both the spatial distribution of the four communities and the factors influencing the distribution found. These primary sources included the use of directories, municipal and archival sources of information, interviews as well the work of various authors. The study found that the spatial distribution of Indians in the four study areas were similar with the Indians occupying residential and commercial premises in the central areas of the urban centres. After 1980 there was a substantial movement to other areas. Prior to 1950 the municipalities played an important role in influencing spatial distribution. However, after the introduction of the Group Areas Act, the govennment controlled Indian spatial distribution. Thus the Group Areas Act was the most important factor affecting Indian spatial distribution. Indians in small urban centres in the Cape Province were segregated and their spatial distribution was controlled both prior to and after 1950. Anti-Indian legislation and restrictions were the main factors influencing Indian spatial distribution.
- Full Text:
- Date Issued: 1995
Biopharmaceutics and pharmacokinetics of the macrolide antibiotic Josamycin
- Authors: Skinner, Michael Fredrick
- Date: 1992
- Subjects: Antibiotics -- Bioavailability , Antibiotics -- Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3791 , http://hdl.handle.net/10962/d1003269
- Description: The investigations detailed herein have been conducted to address various aspects of the biopharmaceutics and pharmacokinetics of josamycin which to-date, have received little or no attention in the literature. Areas of investigation have included the selective determination of josamycin in serum and urine samples, the stability of josamycin in stored biological samples, intrinsic dissolution rates, solubility, acid and alkali stability and bioavailability and pharmacokinetics after dosing with a solution, powder and tablets. High performance liquid chromatography (HPLC) was used as the main analytical tool throughout these studies and proved to be highly versatile for the determination of josamycin in a number of different media. HPLC analysis afforded simple yet accurate determination of josamycin in samples from dissolution, solubility, tablet content and stability studies. Furthermore, the specificity afforded by HPLC was particularly useful for the separation of josamycin from degradation products formed in acid and alkali media. Since metabolites of josamycin are microbiologically active, microbiological assays do not determine the concentration solely of josamycin. An analytical method capable of the selective determination of josamycin in serum and urine samples is therefore required for the procurement of reliable bioavailability and pharmacokinetic data. HPLC affords this selectivity and a method for the selective determination of josamycin in serum and urine was successfully developed. The assay was simple yet precise, accurate and sensitive. Furthermore, it was well suited to the determination of josamycin in a large number of biological samples. Its success was largely due to the use of a solid phase extraction step using C₁₈ extraction columns, with a highly specific wash sequence followed by a phase separation step after elution from the extraction column. Chromatography was performed on a C₁₈ reversed-phase analytical column with UV detection of josamycin and internal standard at 231 nm and at 204 nm respectively using a programmable multi-wavelength detector. Only slight modification of the assay described should enable the selective determination of the metabolites of josamycin. This assay, therefore, lays the groundwork for future investigations into the pharmacokinetics of these metabolites. The re-usability of extraction columns was assessed in an attempt to reduce the cost of sample analysis. It was found that extraction columns could be used twice for the extraction of serum samples and up to four times for the extraction of urine samples. The difference between the re-usability of extraction columns for serum and urine samples was ascribed to various differences in the composition of the sample matrix. The stability of josamycin in stored serum and urine samples was also assessed.
- Full Text:
- Date Issued: 1992
- Authors: Skinner, Michael Fredrick
- Date: 1992
- Subjects: Antibiotics -- Bioavailability , Antibiotics -- Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3791 , http://hdl.handle.net/10962/d1003269
- Description: The investigations detailed herein have been conducted to address various aspects of the biopharmaceutics and pharmacokinetics of josamycin which to-date, have received little or no attention in the literature. Areas of investigation have included the selective determination of josamycin in serum and urine samples, the stability of josamycin in stored biological samples, intrinsic dissolution rates, solubility, acid and alkali stability and bioavailability and pharmacokinetics after dosing with a solution, powder and tablets. High performance liquid chromatography (HPLC) was used as the main analytical tool throughout these studies and proved to be highly versatile for the determination of josamycin in a number of different media. HPLC analysis afforded simple yet accurate determination of josamycin in samples from dissolution, solubility, tablet content and stability studies. Furthermore, the specificity afforded by HPLC was particularly useful for the separation of josamycin from degradation products formed in acid and alkali media. Since metabolites of josamycin are microbiologically active, microbiological assays do not determine the concentration solely of josamycin. An analytical method capable of the selective determination of josamycin in serum and urine samples is therefore required for the procurement of reliable bioavailability and pharmacokinetic data. HPLC affords this selectivity and a method for the selective determination of josamycin in serum and urine was successfully developed. The assay was simple yet precise, accurate and sensitive. Furthermore, it was well suited to the determination of josamycin in a large number of biological samples. Its success was largely due to the use of a solid phase extraction step using C₁₈ extraction columns, with a highly specific wash sequence followed by a phase separation step after elution from the extraction column. Chromatography was performed on a C₁₈ reversed-phase analytical column with UV detection of josamycin and internal standard at 231 nm and at 204 nm respectively using a programmable multi-wavelength detector. Only slight modification of the assay described should enable the selective determination of the metabolites of josamycin. This assay, therefore, lays the groundwork for future investigations into the pharmacokinetics of these metabolites. The re-usability of extraction columns was assessed in an attempt to reduce the cost of sample analysis. It was found that extraction columns could be used twice for the extraction of serum samples and up to four times for the extraction of urine samples. The difference between the re-usability of extraction columns for serum and urine samples was ascribed to various differences in the composition of the sample matrix. The stability of josamycin in stored serum and urine samples was also assessed.
- Full Text:
- Date Issued: 1992
Defined by wine : a study of sacramentalism in George Herbertʾs poetry
- Authors: Goddard, Kevin Graham
- Date: 1988
- Subjects: Herbert, George, 1593-1633 -- Criticism and interpretation , Christian poetry, English -- History and criticism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2177 , http://hdl.handle.net/10962/d1001828
- Description: This dissertation proposes that George Herbertʾs poetry may profitably be understood as a sacramental means by which the divine is made present in temporal existence. In order to support this claim, the relation between sacramental symbolism and literary symbolism, particularly Herbertʾs, is examined from a number of perspectives. The symbolic meanings suggested by Herbertʾs title (The Temple), and their relation to sacramentalism are considered in the opening chapter. This includes a consideration of some of the background to the analogical thinking prevalent in both the seventeenth-century and Herbert. It is followed in the second chapter by an examination of some of the modern theories about how literary symbolism may relate to sacramental symbolism, a discussion which is followed by a consideration of this dissertation's argument in relation to modern scholarship. The chapter ends with a reading of ʺThe Flowerʺ. The third chapter discusses the poet's attempt to imitate the divine by ʺcopyingʺ both Scripture and Nature, and this includes a consideration of the allegorical and hieroglyphic modes of thought prevalent in the poems. The concern with imitation encourages an examination of the poet's frequent invitation for God actually to assume the poet's role, and this is the subject of the fourth chapter. The argument suggests that the poet's attempt to ʺsacrificeʺ his own writing may be seen in his concern with corporate imagery and corporate (impersonal) structures. The five ʺAfflictionʺ poems are examined as examples of the first, while structures such as synecdoche and metonymy are examined as examples of the second. The final chapter considers aspects of narrative time in the poems, particularly the sense often evoked of the eternal being imminent in the present. This involves a consideration of both liturgical imagery, and what may be called liturgical structures as they can be seen to operate in the poems. Particular examples of the latter are the relation between the liturgical anamnesis and the poems, as well as certain narrative structures that may be called ʺachronisticʺ.
- Full Text:
- Date Issued: 1988
- Authors: Goddard, Kevin Graham
- Date: 1988
- Subjects: Herbert, George, 1593-1633 -- Criticism and interpretation , Christian poetry, English -- History and criticism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2177 , http://hdl.handle.net/10962/d1001828
- Description: This dissertation proposes that George Herbertʾs poetry may profitably be understood as a sacramental means by which the divine is made present in temporal existence. In order to support this claim, the relation between sacramental symbolism and literary symbolism, particularly Herbertʾs, is examined from a number of perspectives. The symbolic meanings suggested by Herbertʾs title (The Temple), and their relation to sacramentalism are considered in the opening chapter. This includes a consideration of some of the background to the analogical thinking prevalent in both the seventeenth-century and Herbert. It is followed in the second chapter by an examination of some of the modern theories about how literary symbolism may relate to sacramental symbolism, a discussion which is followed by a consideration of this dissertation's argument in relation to modern scholarship. The chapter ends with a reading of ʺThe Flowerʺ. The third chapter discusses the poet's attempt to imitate the divine by ʺcopyingʺ both Scripture and Nature, and this includes a consideration of the allegorical and hieroglyphic modes of thought prevalent in the poems. The concern with imitation encourages an examination of the poet's frequent invitation for God actually to assume the poet's role, and this is the subject of the fourth chapter. The argument suggests that the poet's attempt to ʺsacrificeʺ his own writing may be seen in his concern with corporate imagery and corporate (impersonal) structures. The five ʺAfflictionʺ poems are examined as examples of the first, while structures such as synecdoche and metonymy are examined as examples of the second. The final chapter considers aspects of narrative time in the poems, particularly the sense often evoked of the eternal being imminent in the present. This involves a consideration of both liturgical imagery, and what may be called liturgical structures as they can be seen to operate in the poems. Particular examples of the latter are the relation between the liturgical anamnesis and the poems, as well as certain narrative structures that may be called ʺachronisticʺ.
- Full Text:
- Date Issued: 1988
- «
- ‹
- 1
- ›
- »