Macro-prudential banking regulation, interest rate spread and the conduct of monetary policy in South Africa
- Shayanewako,Varaidzo Batsirai
- Authors: Shayanewako,Varaidzo Batsirai
- Date: 2018
- Subjects: Monetary policy Economic stabilization
- Language: English
- Type: Thesis , Doctoral , D.Com
- Identifier: http://hdl.handle.net/10353/14093 , vital:39843
- Description: The joint implementation of macro-prudential regulatory and monetary policies is necessary for modern banking systems not only to achieve optimal interest rate spread but to cushion the economy against the catastrophic effects of systemic risk. Therefore, the understanding of the interconnection between macroprudential regulation, interest rate spread and monetary policy, supported with empirical evidence, enables economies to build health and sound financial systems and achieve desirable growth rates. Thus, this study utilises the Vector Error Correction (VEC) mechanism to empirically investigate the interconnection between macro-prudential regulation, interest rate spread and monetary policy in South Africa. Quarterly time series data for the period from 1994 to 2016 was employed with the New Keynesian Dynamic Stochastic General Equilibrium (NKDSGE) model as the framework for analysis. The findings of this study suggest that a negative relationship exists between interest rate spread, macro-prudential regulation and monetary policy in South Africa. Moreover, the systems equation provided evidence that a short run causality running from macroprudential regulation to monetary policy is prevalent in South Africa. The empirical model of the study was found to be desirable as evidence of no serial correlation, no ARCH effect and non-normality in residuals was detected. Evidence from this study further suggest that interest rate spread has a dampening effect on monetary policy, but in the long-run this effect seems reversible in South Africa. As a result, this study recommends that caution should be taken on the appropriate selection of measures of macro-prudential regulation and its tool-kit as it can be used to disguise the symptoms of a lax monetary policy. This implies that the South African Reserve Bank (SARB) should sternly supervise and regulate the extension of credit by commercial banks in line with its inflation targeting monetary policy rule in order to achieve financial stability and ensure optimal interest rate spread that can stimulate the economy to growth.
- Full Text:
- Date Issued: 2018
- Authors: Shayanewako,Varaidzo Batsirai
- Date: 2018
- Subjects: Monetary policy Economic stabilization
- Language: English
- Type: Thesis , Doctoral , D.Com
- Identifier: http://hdl.handle.net/10353/14093 , vital:39843
- Description: The joint implementation of macro-prudential regulatory and monetary policies is necessary for modern banking systems not only to achieve optimal interest rate spread but to cushion the economy against the catastrophic effects of systemic risk. Therefore, the understanding of the interconnection between macroprudential regulation, interest rate spread and monetary policy, supported with empirical evidence, enables economies to build health and sound financial systems and achieve desirable growth rates. Thus, this study utilises the Vector Error Correction (VEC) mechanism to empirically investigate the interconnection between macro-prudential regulation, interest rate spread and monetary policy in South Africa. Quarterly time series data for the period from 1994 to 2016 was employed with the New Keynesian Dynamic Stochastic General Equilibrium (NKDSGE) model as the framework for analysis. The findings of this study suggest that a negative relationship exists between interest rate spread, macro-prudential regulation and monetary policy in South Africa. Moreover, the systems equation provided evidence that a short run causality running from macroprudential regulation to monetary policy is prevalent in South Africa. The empirical model of the study was found to be desirable as evidence of no serial correlation, no ARCH effect and non-normality in residuals was detected. Evidence from this study further suggest that interest rate spread has a dampening effect on monetary policy, but in the long-run this effect seems reversible in South Africa. As a result, this study recommends that caution should be taken on the appropriate selection of measures of macro-prudential regulation and its tool-kit as it can be used to disguise the symptoms of a lax monetary policy. This implies that the South African Reserve Bank (SARB) should sternly supervise and regulate the extension of credit by commercial banks in line with its inflation targeting monetary policy rule in order to achieve financial stability and ensure optimal interest rate spread that can stimulate the economy to growth.
- Full Text:
- Date Issued: 2018
Mannich base metal complexes and their thiocyanate analogues as catalysts in the oxidation of Catechol
- Authors: Ayeni, Ayowole Olaolu
- Date: 2018
- Subjects: Mannich bases , Catechol , Catechol -- Oxidation , Thiocyanates , Catalysts
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62339 , vital:28156
- Description: The study focused on the design of new Cu(II) and Fe(III) complexes, with or without thiocyanate (NCS-), as possible candidates of catechol oxidation using 3,5-di-tert-butyl catechol (3,5-DTBC) as substrate. Two classes of Mannich bases were studied depending on the active methylene group from which they were formed, being either p-cresol or acetaminophen. The ligands were characterised by 1H and 13C NMR spectroscopy. Crystal structures of three of the ligands are newly reported, along with detailed discussion of polymorphism observed in one of the ligands, and the nature of the hydrogen within the ligands in the solid state as well as in solution. The Mannich bases behaved as bidentate (NO), tridentate (NNO) and tetradentate (NNOO) ligands on coordination to Cu(II) and Fe(III) ions in which the hydroxyl group may be protonated or deprotonated. Coordination was determined by IR spectroscopy, investigating shifts in vOH, vC-O and in vCNC of the Mannich bases. The vCNC stretching frequencies v1 and v2 of asymmetrical piperazine Mannich bases were observed to shift upward in few cases upon complexation and this is attributed to (chair-boat) conformational change. The mode of coordination of the thiocyanate was determined by IR spectroscopy. Of the forty metal complexes investigated, six groups of metal complexes were identified as follows: (i) Ma(Ln)aClb-cH2O; (ii) Ma(HLn)a(NCS)aClb; (iii) Ma(Ln)a(NCS)aClb; (iv) Ma(HLn)aClb-cH2O; (v) Ma(Ln)a(NCS)a-cH2O; (vi) Ma(HLn)a(NCS)a-cH2O where a = 1 - 2 ; b = 1 - 4, c = 1 - 8. Molar conductivity values of 4.38 - 161.77 Q-1.cm2.mol-1 for the Cu(II) and Fe(III) complexes in DMSO showed that they range from non-electrolytes to 1:1 and 1:2 electrolytes. Electronic spectra for the ligands and the complexes were conducted in DMF and DMSO. The ligands are characterised by and n→n* and n→n* transitions. Intraligand charge transfer transitions peculiar to the nitro group were observed at about 430 nm for the nitro containing ligands. On coordination, these bands overshadowed the d-d transitions particularly for the nitro-Mannich bases. On complexation, ligand to metal charge transfer transitions associated with the hydroxyl were observed between 320 - 420 nm. Charge transfer transitions associated with the thiocyanates were also observed and discussed. The d-d transitions for high spin Fe(III) complexes are spin forbidden and generally uninformative. Those of Cu(II) are spin allowed and allow tentative structural proposals. Square planar and octahedral geometry are generally prevalent in the Cu(II) complexes with trigonal bipyramidal observed in few instances. The Fe(III) complexes are generally octahedral. Thirty-nine of the forty synthesised Cu(II) and Fe(III) complexes were catalytically active on the substrate (3,5-DTBC) in DMF with turnover rates (kcat) reported in the range of 1.86 ± 0.09 to 112.32 ± 3.72 h-1. From this pool of complexes, sixteen isostructural pairs were identified in terms of geometry, molecular formula and the source of the Mannich base and the following conclusions were made: The presence of thiocyanate in the metal complexes reduce catecholase activity; the Cu(II) complexes generally have better activity but the Fe(III) complexes become more relatively active with highly electron donating groups while the Cu(II) complexes become less; dinuclear complexes have greater activity than the mononuclear.
- Full Text:
- Date Issued: 2018
- Authors: Ayeni, Ayowole Olaolu
- Date: 2018
- Subjects: Mannich bases , Catechol , Catechol -- Oxidation , Thiocyanates , Catalysts
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62339 , vital:28156
- Description: The study focused on the design of new Cu(II) and Fe(III) complexes, with or without thiocyanate (NCS-), as possible candidates of catechol oxidation using 3,5-di-tert-butyl catechol (3,5-DTBC) as substrate. Two classes of Mannich bases were studied depending on the active methylene group from which they were formed, being either p-cresol or acetaminophen. The ligands were characterised by 1H and 13C NMR spectroscopy. Crystal structures of three of the ligands are newly reported, along with detailed discussion of polymorphism observed in one of the ligands, and the nature of the hydrogen within the ligands in the solid state as well as in solution. The Mannich bases behaved as bidentate (NO), tridentate (NNO) and tetradentate (NNOO) ligands on coordination to Cu(II) and Fe(III) ions in which the hydroxyl group may be protonated or deprotonated. Coordination was determined by IR spectroscopy, investigating shifts in vOH, vC-O and in vCNC of the Mannich bases. The vCNC stretching frequencies v1 and v2 of asymmetrical piperazine Mannich bases were observed to shift upward in few cases upon complexation and this is attributed to (chair-boat) conformational change. The mode of coordination of the thiocyanate was determined by IR spectroscopy. Of the forty metal complexes investigated, six groups of metal complexes were identified as follows: (i) Ma(Ln)aClb-cH2O; (ii) Ma(HLn)a(NCS)aClb; (iii) Ma(Ln)a(NCS)aClb; (iv) Ma(HLn)aClb-cH2O; (v) Ma(Ln)a(NCS)a-cH2O; (vi) Ma(HLn)a(NCS)a-cH2O where a = 1 - 2 ; b = 1 - 4, c = 1 - 8. Molar conductivity values of 4.38 - 161.77 Q-1.cm2.mol-1 for the Cu(II) and Fe(III) complexes in DMSO showed that they range from non-electrolytes to 1:1 and 1:2 electrolytes. Electronic spectra for the ligands and the complexes were conducted in DMF and DMSO. The ligands are characterised by and n→n* and n→n* transitions. Intraligand charge transfer transitions peculiar to the nitro group were observed at about 430 nm for the nitro containing ligands. On coordination, these bands overshadowed the d-d transitions particularly for the nitro-Mannich bases. On complexation, ligand to metal charge transfer transitions associated with the hydroxyl were observed between 320 - 420 nm. Charge transfer transitions associated with the thiocyanates were also observed and discussed. The d-d transitions for high spin Fe(III) complexes are spin forbidden and generally uninformative. Those of Cu(II) are spin allowed and allow tentative structural proposals. Square planar and octahedral geometry are generally prevalent in the Cu(II) complexes with trigonal bipyramidal observed in few instances. The Fe(III) complexes are generally octahedral. Thirty-nine of the forty synthesised Cu(II) and Fe(III) complexes were catalytically active on the substrate (3,5-DTBC) in DMF with turnover rates (kcat) reported in the range of 1.86 ± 0.09 to 112.32 ± 3.72 h-1. From this pool of complexes, sixteen isostructural pairs were identified in terms of geometry, molecular formula and the source of the Mannich base and the following conclusions were made: The presence of thiocyanate in the metal complexes reduce catecholase activity; the Cu(II) complexes generally have better activity but the Fe(III) complexes become more relatively active with highly electron donating groups while the Cu(II) complexes become less; dinuclear complexes have greater activity than the mononuclear.
- Full Text:
- Date Issued: 2018
Microfinace and poverty alleviation in Uganda
- Authors: Ben, Ssembajjwe
- Date: 2018
- Subjects: Microfinance -- Uganda , Economic development -- Uganda Economic assistance, Domestic Poverty -- Economic aspects -- Uganda
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23624 , vital:30588
- Description: Microfinance began in Uganda in the early 1990s as a response to the failure by formal financial institutions to extend financial services to the poor because of the high transaction costs involved. These microfinance institutions provide financial and non-financial services to the poor in order for the poor to generate incomes and consequently alleviate poverty. The advent of microfinance institutions was not accidental but rather in response to the people’s needs and they have therefore been beneficial for the people of Uganda. Because of that, several MFIs have been initiated to help the poor. Although many services are provided, the study focused on credit services. As most of the MFIs have to balance the business goal of profit maximization and the social goal of poverty reduction, the main objective of this study was to explore whether microfinance in Uganda is an effective tool for poverty alleviation. The study was conducted in four districts, namely Mukono, Mpigi, Wakiso and Luwero. Using random probability sampling, a sample of 170 was drawn from a pool of 300 MFI clients. and all of them responded. MFI officials were also interviewed. A total 136 officials were obtained from 47 MFI branches. The study used descriptive methods of analysis, a Likert scale to derive means, as well as a Principal Component Analysis technique. Analysis of variance (ANOVA) was used to detect if there were any statistically significant differences among the demographic variables used in the study. A Probit Regression Model was used to determine the impact of certain variables drawn from Principal Component Analysis (PCA) on poverty in Uganda. The results obtained proved that MFIs in general are effective in combating poverty in Uganda. Variables that are significant in poverty reduction through loan use are land, education, employment, household incomes and occupations of the respondents, loan sizes and improved livelihoods. Despite the positive impact of MFI loans in Uganda, the MFIs are faced with a number of challenges. The results from the interviews with the MFI officials indicated that MFIs are challenged by increasing competition, bad debt, multiple borrowings by clients, and information asymmetry. The study recommended reduced interest rates on agricultural, education and business loans. The public must also be sensitised about borrowing and there should be increased monitoring and supervision of clients, improved assessment of creditworthiness, and government should ensure an enabling environment and encourage group loans. Effort should be exerted to create employment opportunities. The study also recommended improvement in market intelligence and to be alert in gathering information on client profiles. it was recommended that microloan insurance and savings must be encouraged, operational costs be reduced, portfolios be expanded to increase loans and outreach must be maximised. Lastly, the thesis put forward some potential areas for further studies.
- Full Text:
- Date Issued: 2018
- Authors: Ben, Ssembajjwe
- Date: 2018
- Subjects: Microfinance -- Uganda , Economic development -- Uganda Economic assistance, Domestic Poverty -- Economic aspects -- Uganda
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23624 , vital:30588
- Description: Microfinance began in Uganda in the early 1990s as a response to the failure by formal financial institutions to extend financial services to the poor because of the high transaction costs involved. These microfinance institutions provide financial and non-financial services to the poor in order for the poor to generate incomes and consequently alleviate poverty. The advent of microfinance institutions was not accidental but rather in response to the people’s needs and they have therefore been beneficial for the people of Uganda. Because of that, several MFIs have been initiated to help the poor. Although many services are provided, the study focused on credit services. As most of the MFIs have to balance the business goal of profit maximization and the social goal of poverty reduction, the main objective of this study was to explore whether microfinance in Uganda is an effective tool for poverty alleviation. The study was conducted in four districts, namely Mukono, Mpigi, Wakiso and Luwero. Using random probability sampling, a sample of 170 was drawn from a pool of 300 MFI clients. and all of them responded. MFI officials were also interviewed. A total 136 officials were obtained from 47 MFI branches. The study used descriptive methods of analysis, a Likert scale to derive means, as well as a Principal Component Analysis technique. Analysis of variance (ANOVA) was used to detect if there were any statistically significant differences among the demographic variables used in the study. A Probit Regression Model was used to determine the impact of certain variables drawn from Principal Component Analysis (PCA) on poverty in Uganda. The results obtained proved that MFIs in general are effective in combating poverty in Uganda. Variables that are significant in poverty reduction through loan use are land, education, employment, household incomes and occupations of the respondents, loan sizes and improved livelihoods. Despite the positive impact of MFI loans in Uganda, the MFIs are faced with a number of challenges. The results from the interviews with the MFI officials indicated that MFIs are challenged by increasing competition, bad debt, multiple borrowings by clients, and information asymmetry. The study recommended reduced interest rates on agricultural, education and business loans. The public must also be sensitised about borrowing and there should be increased monitoring and supervision of clients, improved assessment of creditworthiness, and government should ensure an enabling environment and encourage group loans. Effort should be exerted to create employment opportunities. The study also recommended improvement in market intelligence and to be alert in gathering information on client profiles. it was recommended that microloan insurance and savings must be encouraged, operational costs be reduced, portfolios be expanded to increase loans and outreach must be maximised. Lastly, the thesis put forward some potential areas for further studies.
- Full Text:
- Date Issued: 2018
Modelling Ionospheric vertical drifts over the African low latitude region
- Dubazane, Makhosonke Berthwell
- Authors: Dubazane, Makhosonke Berthwell
- Date: 2018
- Subjects: Ionospheric drift , Magnetometers , Functions, Orthogonal , Neural networks (Computer science) , Ionospheric electron density -- Africa , Communication and Navigation Outage Forecasting Systems (C/NOFS)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63356 , vital:28396
- Description: Low/equatorial latitudes vertical plasma drifts and electric fields govern the formation and changes of ionospheric density structures which affect space-based systems such as communications, navigation and positioning. Dynamical and electrodynamical processes play important roles in plasma distribution at different altitudes. Because of the high variability of E × B drift in low latitude regions, coupled with various processes that sometimes originate from high latitudes especially during geomagnetic storm conditions, it is challenging to develop accurate vertical drift models. This is despite the fact that there are very few instruments dedicated to provide electric field and hence E × B drift data in low/equatorial latitude regions. To this effect, there exists no ground-based instrument for direct measurements of E×B drift data in the African sector. This study presents the first time investigation aimed at modelling the long-term variability of low latitude vertical E × B drift over the African sector using a combination of Communication and Navigation Outage Forecasting Systems (C/NOFS) and ground-based magnetometer observations/measurements during 2008-2013. Because the approach is based on the estimation of equatorial electrojet from ground-based magnetometer observations, the developed models are only valid for local daytime. Three modelling techniques have been considered. The application of Empirical Orthogonal Functions and partial least squares has been performed on vertical E × B drift modelling for the first time. The artificial neural networks that have the advantage of learning underlying changes between a set of inputs and known output were also used in vertical E × B drift modelling. Due to lack of E×B drift data over the African sector, the developed models were validated using satellite data and the climatological Scherliess-Fejer model incorporated within the International Reference Ionosphere model. Maximum correlation coefficient of ∼ 0.8 was achieved when validating the developed models with C/NOFS E × B drift observations that were not used in any model development. For most of the time, the climatological model overestimates the local daytime vertical E × B drift velocities. The methods and approach presented in this study provide a background for constructing vertical E ×B drift databases in longitude sectors that do not have radar instrumentation. This will in turn make it possible to study day-to-day variability of vertical E×B drift and hopefully lead to the development of regional and global models that will incorporate local time information in different longitude sectors.
- Full Text:
- Date Issued: 2018
- Authors: Dubazane, Makhosonke Berthwell
- Date: 2018
- Subjects: Ionospheric drift , Magnetometers , Functions, Orthogonal , Neural networks (Computer science) , Ionospheric electron density -- Africa , Communication and Navigation Outage Forecasting Systems (C/NOFS)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63356 , vital:28396
- Description: Low/equatorial latitudes vertical plasma drifts and electric fields govern the formation and changes of ionospheric density structures which affect space-based systems such as communications, navigation and positioning. Dynamical and electrodynamical processes play important roles in plasma distribution at different altitudes. Because of the high variability of E × B drift in low latitude regions, coupled with various processes that sometimes originate from high latitudes especially during geomagnetic storm conditions, it is challenging to develop accurate vertical drift models. This is despite the fact that there are very few instruments dedicated to provide electric field and hence E × B drift data in low/equatorial latitude regions. To this effect, there exists no ground-based instrument for direct measurements of E×B drift data in the African sector. This study presents the first time investigation aimed at modelling the long-term variability of low latitude vertical E × B drift over the African sector using a combination of Communication and Navigation Outage Forecasting Systems (C/NOFS) and ground-based magnetometer observations/measurements during 2008-2013. Because the approach is based on the estimation of equatorial electrojet from ground-based magnetometer observations, the developed models are only valid for local daytime. Three modelling techniques have been considered. The application of Empirical Orthogonal Functions and partial least squares has been performed on vertical E × B drift modelling for the first time. The artificial neural networks that have the advantage of learning underlying changes between a set of inputs and known output were also used in vertical E × B drift modelling. Due to lack of E×B drift data over the African sector, the developed models were validated using satellite data and the climatological Scherliess-Fejer model incorporated within the International Reference Ionosphere model. Maximum correlation coefficient of ∼ 0.8 was achieved when validating the developed models with C/NOFS E × B drift observations that were not used in any model development. For most of the time, the climatological model overestimates the local daytime vertical E × B drift velocities. The methods and approach presented in this study provide a background for constructing vertical E ×B drift databases in longitude sectors that do not have radar instrumentation. This will in turn make it possible to study day-to-day variability of vertical E×B drift and hopefully lead to the development of regional and global models that will incorporate local time information in different longitude sectors.
- Full Text:
- Date Issued: 2018
Modelling plant water use of the grassland and thicket biomes in the Eastern Cape, South Africa: towards an improved understanding of the impact of invasive alien plants on soil chemistry, biomass production and evapotranspiration
- Authors: Gwate, Onalenna
- Date: 2018
- Subjects: Grasslands -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Rangelands -- South Africa -- Eastern Cape , Range ecology-- South Africa -- Eastern Cape , Rangelands -- Water-supply , Rangelands -- Weed control , Evapotranspiration , Plant-water relationships
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54800 , vital:26617
- Description: It is imperative to understand the strong coupling between the carbon capture process and water use to sustainably manage rangelands. Woody encroachment is undermining rangelands grass production. Evapotranspiration (ET) highlights the links between ecosystem carbon capture process and water use. It forms the biggest flux of the hydrological cycle after precipitation yet it is not well understood. The Grassland and the Albany Thicket (AT) biomes in the Eastern Cape, South Africa, provide an interesting space to study the dynamics in rangelands biomass production and the associated water use. Therefore, the main purpose of this study was to contribute towards management of rangelands by understanding the dynamics in rangeland grass production and water use. To achieve this aim, the impact of Acacia mearnsii, an invasive alien plant, on soil chemical properties and rangelands grass production was investigated. This was achieved by analysing the biophysical attributes of A. mearnsii as they related to grass production. Secondly, selected soil variables that could be used as a prognosis for landscape recovery or deterioration were evaluated. In addition, aboveground grass biomass was measured in areas cleared of A. mearnsii and regression equations were prepared to help model aboveground grass biomass in areas cleared of A. mearnsi. The thesis also explored dynamics in water vapour and energy fluxes in these two biomes using an eddy covariance system. Consequently, water vapour and energy fluxes were evaluated in order to understand landscape water use and energy partitioning in the landscape. The study also tested the application of Penman-Monteith equation based algorithms for estimating ET with micrometeorological techniques used for validation. Pursuant to this, the Penman- Monteith-Leuning (PML) and Penman-Monteith-Palmer (PMP) equations were applied. In addition, some effort was devoted to improving the estimates of ET from the PMP by incorporating a direct soil evaporation component. Finally, the influence of local changes in catchment characteristics on ET was explored through the application of a variant of the Budyko framework and investigating dynamics in the evaporative index as well as applying tests for trends and shifts on ET and rainfall data to detect changes in mean quaternary catchment rainfall and ET. Results revealed that A. mearnsii affected soil chemical properties and impaired grass production in rangelands. Hence, thinning of canopies provided an optimal solution for enhanced landscape water use to sequestrate carbon, provide shade, grazing, and also wood fuel. It was also shown that across sites, ET was water limited since differences between reference ET and actual ET were large. ET was largely sensitive to vapour pressure deficit and surface conductance than to net radiation, indicating that the canopies were strongly coupled with the boundary layer. Rangeland ET was successfully simulated and evaporation from the soil was the dominant flux, hence there is scope for reducing the so-called ‘unproductive’ water use. Further, it was shown that the PML was better able to simulate ET compared to the PMP model as revealed by different model evaluation metrics such as the root mean square error, absolute mean square error and the root mean square observations standard deviation ratio. The incorporation of a soil evaporation component in the PMP model improved estimates of ET as revealed by the root mean square error. The results also indicated that both the catchment parameter (w) and the evaporative index were important in highlighting the impacts of land cover change on ET. It was also shown that, despite changes in the local environment such as catchment characteristics, global forces also affected ET at a local scale. Overall, the study demonstrated that combining remote sensing and ground based observations was important to better understand rangeland grass production and water use dynamics.
- Full Text:
- Date Issued: 2018
- Authors: Gwate, Onalenna
- Date: 2018
- Subjects: Grasslands -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Rangelands -- South Africa -- Eastern Cape , Range ecology-- South Africa -- Eastern Cape , Rangelands -- Water-supply , Rangelands -- Weed control , Evapotranspiration , Plant-water relationships
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54800 , vital:26617
- Description: It is imperative to understand the strong coupling between the carbon capture process and water use to sustainably manage rangelands. Woody encroachment is undermining rangelands grass production. Evapotranspiration (ET) highlights the links between ecosystem carbon capture process and water use. It forms the biggest flux of the hydrological cycle after precipitation yet it is not well understood. The Grassland and the Albany Thicket (AT) biomes in the Eastern Cape, South Africa, provide an interesting space to study the dynamics in rangelands biomass production and the associated water use. Therefore, the main purpose of this study was to contribute towards management of rangelands by understanding the dynamics in rangeland grass production and water use. To achieve this aim, the impact of Acacia mearnsii, an invasive alien plant, on soil chemical properties and rangelands grass production was investigated. This was achieved by analysing the biophysical attributes of A. mearnsii as they related to grass production. Secondly, selected soil variables that could be used as a prognosis for landscape recovery or deterioration were evaluated. In addition, aboveground grass biomass was measured in areas cleared of A. mearnsii and regression equations were prepared to help model aboveground grass biomass in areas cleared of A. mearnsi. The thesis also explored dynamics in water vapour and energy fluxes in these two biomes using an eddy covariance system. Consequently, water vapour and energy fluxes were evaluated in order to understand landscape water use and energy partitioning in the landscape. The study also tested the application of Penman-Monteith equation based algorithms for estimating ET with micrometeorological techniques used for validation. Pursuant to this, the Penman- Monteith-Leuning (PML) and Penman-Monteith-Palmer (PMP) equations were applied. In addition, some effort was devoted to improving the estimates of ET from the PMP by incorporating a direct soil evaporation component. Finally, the influence of local changes in catchment characteristics on ET was explored through the application of a variant of the Budyko framework and investigating dynamics in the evaporative index as well as applying tests for trends and shifts on ET and rainfall data to detect changes in mean quaternary catchment rainfall and ET. Results revealed that A. mearnsii affected soil chemical properties and impaired grass production in rangelands. Hence, thinning of canopies provided an optimal solution for enhanced landscape water use to sequestrate carbon, provide shade, grazing, and also wood fuel. It was also shown that across sites, ET was water limited since differences between reference ET and actual ET were large. ET was largely sensitive to vapour pressure deficit and surface conductance than to net radiation, indicating that the canopies were strongly coupled with the boundary layer. Rangeland ET was successfully simulated and evaporation from the soil was the dominant flux, hence there is scope for reducing the so-called ‘unproductive’ water use. Further, it was shown that the PML was better able to simulate ET compared to the PMP model as revealed by different model evaluation metrics such as the root mean square error, absolute mean square error and the root mean square observations standard deviation ratio. The incorporation of a soil evaporation component in the PMP model improved estimates of ET as revealed by the root mean square error. The results also indicated that both the catchment parameter (w) and the evaporative index were important in highlighting the impacts of land cover change on ET. It was also shown that, despite changes in the local environment such as catchment characteristics, global forces also affected ET at a local scale. Overall, the study demonstrated that combining remote sensing and ground based observations was important to better understand rangeland grass production and water use dynamics.
- Full Text:
- Date Issued: 2018
Molecular characterization of streptococcus agalactiae isolated from pregnant women in the Eastern Cape, South Africa and Windhoek, Namibia and antibacterial activities of some medicinal plant extracts on the isolates
- Authors: Mukesi, Munyaradzi
- Date: 2018
- Subjects: Streptococcus Medicinal plants Pregnant women
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/13034 , vital:39437
- Description: Streptococcus agalactiae (S. agalactiae) also known as group B Streptococcus (GBS) is one of the leading causes of bacterial morbidity and mortality among neonates worldwide. It is the cause of invasive Early Onset Disease (EOD), which occurs in the first 7 days of life and characterised by sepsis, pneumonia and meningitis and Late Onset Disease (LOD) occurring between 7 and 89 days of life. Late onset disease is characterised by meningitis and long term neurological sequelae such as cerebral palsy, hearing impairment and cognitive challenges. S. agalactiae does not only infect neonates, it also infects the elderly, immunocompromised individuals and pregnant and non-pregnant women, causing invasive disease. In the world, 10-40 percent of healthy women are rectally or vaginally colonised with GBS and they face the risk of passing it to their babies during the process of childbirth. During parturition, a GBS colonized pregnant woman transfers the bacterium to her new-born as the baby passes through the ruptured membrane, thus infecting the child. However, GBS has been reported to be transferred even without rupture of membranes. Once it infects the membranes, it is transferred into the amniotic fluid and subsequently infects the baby. It can be aspirated into the lungs causing pneumonia or it can infect the blood stream and disseminated round the body causing septicaemia, meningitis and other infections. Once in the neonate’s body, the bacteria is able to evade the immune system as the host immune system is not yet fully developed. Bacterial evasion of the immune system is enhanced by its various virulence factors which are deployed to help it escape the immune system. These include the polysaccharide capsule, haemolysin and the release of complement inactivating factors such C5a peptidase. The World Health Organisation (WHO) (2010) recommends universal screening of pregnant women to identify those colonised and who are at risk of passing the bacterium to their babies during birth. WHO also recommends identification of at risk women and providing Intrapartum Antibiotic Prophylaxis (IAP) using penicillin. However, problems arise in penicillin allergic women and while alternatives for IAP include erythromycin and clindamycin, there is increasing resistance to these drugs thereby limiting therapeutic options. Antimicrobial susceptibility testing is also not always possible in most resource constrained countries due to poor infrastructure, limited access to health care and the logistical problems in implementing the WHO guidelines. Alternative therapeutic options to GBS infection include developing new and potent antibiotics, development of a vaccine, use of medicinal plants and the use of bacteriophage therapy. While these look like better alternatives there is massive scientific work to be carried out to ensure proper characterisation and efficiency of such alternatives. This process should be followed by in vitro diagnostic testing, experiments with animal models and clinical trials. The problems encountered during vaccine development to curtail GBS infection are compounded by the multiplicity of S. agalactiae capsular types which vary in different geographic locations. Medicinal plants are a cheap and convenient option since they are widely used in communities but the phytochemical components of the plants have to be identified and subjected to in vitro testing to evaluate their therapeutic efficacy as antimicrobial agents. This study therefore sought to isolate GBS from pregnant women between 35 and 37 weeks gestation in Windhoek (Namibia) and the Eastern Cape (South Africa), to determine the prevalence of GBS colonisation in the vagina and rectum of the pregnant women, characterise the isolates by molecular techniques, determine the antimicrobial resistance profiles and genes of the isolates and explore the efficacies of medicinal plant extracts as possible candidates for therapeutic options.
- Full Text:
- Date Issued: 2018
- Authors: Mukesi, Munyaradzi
- Date: 2018
- Subjects: Streptococcus Medicinal plants Pregnant women
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/13034 , vital:39437
- Description: Streptococcus agalactiae (S. agalactiae) also known as group B Streptococcus (GBS) is one of the leading causes of bacterial morbidity and mortality among neonates worldwide. It is the cause of invasive Early Onset Disease (EOD), which occurs in the first 7 days of life and characterised by sepsis, pneumonia and meningitis and Late Onset Disease (LOD) occurring between 7 and 89 days of life. Late onset disease is characterised by meningitis and long term neurological sequelae such as cerebral palsy, hearing impairment and cognitive challenges. S. agalactiae does not only infect neonates, it also infects the elderly, immunocompromised individuals and pregnant and non-pregnant women, causing invasive disease. In the world, 10-40 percent of healthy women are rectally or vaginally colonised with GBS and they face the risk of passing it to their babies during the process of childbirth. During parturition, a GBS colonized pregnant woman transfers the bacterium to her new-born as the baby passes through the ruptured membrane, thus infecting the child. However, GBS has been reported to be transferred even without rupture of membranes. Once it infects the membranes, it is transferred into the amniotic fluid and subsequently infects the baby. It can be aspirated into the lungs causing pneumonia or it can infect the blood stream and disseminated round the body causing septicaemia, meningitis and other infections. Once in the neonate’s body, the bacteria is able to evade the immune system as the host immune system is not yet fully developed. Bacterial evasion of the immune system is enhanced by its various virulence factors which are deployed to help it escape the immune system. These include the polysaccharide capsule, haemolysin and the release of complement inactivating factors such C5a peptidase. The World Health Organisation (WHO) (2010) recommends universal screening of pregnant women to identify those colonised and who are at risk of passing the bacterium to their babies during birth. WHO also recommends identification of at risk women and providing Intrapartum Antibiotic Prophylaxis (IAP) using penicillin. However, problems arise in penicillin allergic women and while alternatives for IAP include erythromycin and clindamycin, there is increasing resistance to these drugs thereby limiting therapeutic options. Antimicrobial susceptibility testing is also not always possible in most resource constrained countries due to poor infrastructure, limited access to health care and the logistical problems in implementing the WHO guidelines. Alternative therapeutic options to GBS infection include developing new and potent antibiotics, development of a vaccine, use of medicinal plants and the use of bacteriophage therapy. While these look like better alternatives there is massive scientific work to be carried out to ensure proper characterisation and efficiency of such alternatives. This process should be followed by in vitro diagnostic testing, experiments with animal models and clinical trials. The problems encountered during vaccine development to curtail GBS infection are compounded by the multiplicity of S. agalactiae capsular types which vary in different geographic locations. Medicinal plants are a cheap and convenient option since they are widely used in communities but the phytochemical components of the plants have to be identified and subjected to in vitro testing to evaluate their therapeutic efficacy as antimicrobial agents. This study therefore sought to isolate GBS from pregnant women between 35 and 37 weeks gestation in Windhoek (Namibia) and the Eastern Cape (South Africa), to determine the prevalence of GBS colonisation in the vagina and rectum of the pregnant women, characterise the isolates by molecular techniques, determine the antimicrobial resistance profiles and genes of the isolates and explore the efficacies of medicinal plant extracts as possible candidates for therapeutic options.
- Full Text:
- Date Issued: 2018
Molecular epidemiology of vibrio pathogens in selected surface waters and treated final effluents of wastewater treatment plants in Chris Hani District Municipality in the Eastern Cape Province, South Africa
- Authors: Ayodeji, Onsula Charles
- Date: 2018
- Subjects: Sewage disposal plants Sewage -- Purification Water -- Purification -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Microbiology
- Identifier: http://hdl.handle.net/10353/10464 , vital:35478
- Description: Access to clean and safe water is essential for the survival of human beings. Nevertheless pollution from wastewater treatment plants (WWTPs) effluents often impacts the microbiological qualities of surface waters. Availability of freshwater resources is indispensable for preventing waterborne diseases. The current study evaluated the physicochemical properties and abundance of Vibrio species in selected rivers and WWTPs in the Eastern Cape Province of South Africa, over a one year sampling regime (December, 2016 to November, 2017). Water samples were collected monthly at designated locations along the banks of two rivers, treated effluents from 500 m upstream and downstream discharge points of two WWTPs and examined for physicochemical qualities, prevalence of Vibrio pathogens and their antibiogram profiles using both cultural and molecular techniques. The findings reveal the qualities of Tsomo and Great Fish river qualities with respect to electrical conductivity (EC) (137.75 – 377.69 mg/l), total suspended solids (TSS) (52.00 – 725.19 mg/l) and temperature (12.7 – 23 oC) and the treated effluents of WW-AD and WW-CR WWTPs with respect to EC (525.73 – 1071.89 mg/l), free chlorine (0.00 mg/l – 0.68 mg/l), temperature (12.4 – 28.8 oC), TSS (14.67 – 276.44 mg/l) exceeds the permissible limits set for effluent discharged to freshwater by South Africa guidelines. Other physicochemical qualities such as turbidity (63.11 – 797.17 NTU), BOD (3.30 – 5.26 mg/l) and TDS (68.88 – 148.14 mg/l) for Tsomo and Great Fish river and turbidity (20.33 – 310 NTU), biological oxygen demand (BOD) (1.28 – 4.96 mg/l), and total dissolve solid (TDS) (262.89 – 534.89 mg/l) for WWTPs WW-AD and WW-CR did not comply with WHO and EU standards as no regulation is set for them in the South African guidelines for domestic water usage. Statistical analysis revealed that pH, electrical conductivities, dissolved oxygen and total dissolved solid were significantly different whereas temperature did not differ significantly with respect to the four seasons (P < 0.05). The Vibrio densities for Great Fish river ranged between 0 and 3.29 log10 CFU/ml with the highest obtained in the spring. The Tsomo River Vibrio densities varied between 0 to 3.56 log10 CFU/ml and the maximum densities recorded during summer. The presumptive Vibrio densities in WW-AD and WW-CR WWTPs ranged from 0 to 3.67 log10 CFU/ml and 0 to 4.42 log10 CFU/ml with autumn and spring having the highest loads respectively. Molecular identification of the presumptive Vibrio species revealed 424 positive for the Vibrio genus. Of these, 21.69 percent, 11.79 percent, 8.25 percent and 2.12 percent were confirmed as V. cholerae, V. mimicus, V. parahaemolyticus and V. fluvialis respectively. The presence of potentially Vibrio pathogens in the rivers and treated effluents suggests potential public health threat to the communities relying on receiving watersheds where the effluents are discharged. Results of antibiotic sensitivity testing revealed high sensitivities against Ofloxacin (85.54 percent), Cefuroxime (81.93 percent), and Ciprofloxacin (74.70 percent), whereas resistance against other antibiotics follow this order: Imipenem (42.17 percent), Amoxicillin-Clavulanic Acid (54.17 percent), Ampicillin (63.54 percent), Nitrofurantoin (71.79 percent) and Polymyxin B (97.44 percent). Surprisingly, the resistance of Vibrio species against the known effective Carbapenems was relatively high (Meropenem (38.54 percent) and Imipenem (58.88 percent). Multiple antibiotic resistance phenotypes (MARP) of the isolates were resistant to two or more antibiotics whereas the calculated multiple antibiotic resistance index (MARI) ranged from 0.2 to 0.7. The observed high multiple antibiotics index suggest the recovered Vibrio pathogens are of high antimicrobial usage origin. Increase in antimicrobial resistance profiles towards conventionally used antibiotics as indicated in this study calls for adequate sanitation facilities and proper surveillance programs towards monitoring of antimicrobial resistance determinants in wastewater treatment effluents and receiving watersheds. This will in turn enhance early detection of resistant strains of public health importance, and supports the prompt notification and investigation of outbreaks. It further advocates the need for constant monitoring programme by the relevant regulatory agencies to ensure total compliance of the wastewater treatment facilities to the stipulated standards.
- Full Text:
- Date Issued: 2018
- Authors: Ayodeji, Onsula Charles
- Date: 2018
- Subjects: Sewage disposal plants Sewage -- Purification Water -- Purification -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Microbiology
- Identifier: http://hdl.handle.net/10353/10464 , vital:35478
- Description: Access to clean and safe water is essential for the survival of human beings. Nevertheless pollution from wastewater treatment plants (WWTPs) effluents often impacts the microbiological qualities of surface waters. Availability of freshwater resources is indispensable for preventing waterborne diseases. The current study evaluated the physicochemical properties and abundance of Vibrio species in selected rivers and WWTPs in the Eastern Cape Province of South Africa, over a one year sampling regime (December, 2016 to November, 2017). Water samples were collected monthly at designated locations along the banks of two rivers, treated effluents from 500 m upstream and downstream discharge points of two WWTPs and examined for physicochemical qualities, prevalence of Vibrio pathogens and their antibiogram profiles using both cultural and molecular techniques. The findings reveal the qualities of Tsomo and Great Fish river qualities with respect to electrical conductivity (EC) (137.75 – 377.69 mg/l), total suspended solids (TSS) (52.00 – 725.19 mg/l) and temperature (12.7 – 23 oC) and the treated effluents of WW-AD and WW-CR WWTPs with respect to EC (525.73 – 1071.89 mg/l), free chlorine (0.00 mg/l – 0.68 mg/l), temperature (12.4 – 28.8 oC), TSS (14.67 – 276.44 mg/l) exceeds the permissible limits set for effluent discharged to freshwater by South Africa guidelines. Other physicochemical qualities such as turbidity (63.11 – 797.17 NTU), BOD (3.30 – 5.26 mg/l) and TDS (68.88 – 148.14 mg/l) for Tsomo and Great Fish river and turbidity (20.33 – 310 NTU), biological oxygen demand (BOD) (1.28 – 4.96 mg/l), and total dissolve solid (TDS) (262.89 – 534.89 mg/l) for WWTPs WW-AD and WW-CR did not comply with WHO and EU standards as no regulation is set for them in the South African guidelines for domestic water usage. Statistical analysis revealed that pH, electrical conductivities, dissolved oxygen and total dissolved solid were significantly different whereas temperature did not differ significantly with respect to the four seasons (P < 0.05). The Vibrio densities for Great Fish river ranged between 0 and 3.29 log10 CFU/ml with the highest obtained in the spring. The Tsomo River Vibrio densities varied between 0 to 3.56 log10 CFU/ml and the maximum densities recorded during summer. The presumptive Vibrio densities in WW-AD and WW-CR WWTPs ranged from 0 to 3.67 log10 CFU/ml and 0 to 4.42 log10 CFU/ml with autumn and spring having the highest loads respectively. Molecular identification of the presumptive Vibrio species revealed 424 positive for the Vibrio genus. Of these, 21.69 percent, 11.79 percent, 8.25 percent and 2.12 percent were confirmed as V. cholerae, V. mimicus, V. parahaemolyticus and V. fluvialis respectively. The presence of potentially Vibrio pathogens in the rivers and treated effluents suggests potential public health threat to the communities relying on receiving watersheds where the effluents are discharged. Results of antibiotic sensitivity testing revealed high sensitivities against Ofloxacin (85.54 percent), Cefuroxime (81.93 percent), and Ciprofloxacin (74.70 percent), whereas resistance against other antibiotics follow this order: Imipenem (42.17 percent), Amoxicillin-Clavulanic Acid (54.17 percent), Ampicillin (63.54 percent), Nitrofurantoin (71.79 percent) and Polymyxin B (97.44 percent). Surprisingly, the resistance of Vibrio species against the known effective Carbapenems was relatively high (Meropenem (38.54 percent) and Imipenem (58.88 percent). Multiple antibiotic resistance phenotypes (MARP) of the isolates were resistant to two or more antibiotics whereas the calculated multiple antibiotic resistance index (MARI) ranged from 0.2 to 0.7. The observed high multiple antibiotics index suggest the recovered Vibrio pathogens are of high antimicrobial usage origin. Increase in antimicrobial resistance profiles towards conventionally used antibiotics as indicated in this study calls for adequate sanitation facilities and proper surveillance programs towards monitoring of antimicrobial resistance determinants in wastewater treatment effluents and receiving watersheds. This will in turn enhance early detection of resistant strains of public health importance, and supports the prompt notification and investigation of outbreaks. It further advocates the need for constant monitoring programme by the relevant regulatory agencies to ensure total compliance of the wastewater treatment facilities to the stipulated standards.
- Full Text:
- Date Issued: 2018
Molecular studies on cholera and non-cholera causing vibrio pathogens isolated from some water resources and aquatic animals in Eastern Cape Province, South Africa
- Authors: Abioye, Oluwatayo Emmanuel
- Date: 2018
- Subjects: Vibrio cholerae -- Pathogens Vibrio cholerae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9154 , vital:34283
- Description: The global socioeconomic and disease burdens of cholera; a disease caused by Vibrio cholerae have been ongoing since it was first reported in India in 1563. Unfortunately, emerging non-cholera causing Vibrio pathogens have been contributing to the malady of Vibrio genus globally in the recent years. The history of cholera outbreaks in South Africa have been well documented but information regarding other non-cholera Vibrio pathogens, is deficient in the literature. This study evaluated the statuses of aquatic animals including crustaceans, molluscs, and fish as important reservoirs of six key pathogenic Vibrio spp. in some important water resources and fish markets in the Eastern Cape, South Africa, between December 2016 and November 2017. Physiochemical parameters that are vital for water quality assessment were determined for all the water sampling points using standard methods. The parameters include pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, temperature, total dissolved solids, turbidity and biological oxygen demand (BOD5). Vibrio spp. densities in water and aquatic animal samples were determined using membrane filtration and Most Probable NumberPolymerase chain reaction (MPN-PCR) methods respectively. Presumptive Vibrio spp. were recovered from the samples by direct plating of water samples and aliquots of aquatic animal homogenates on thiosulfate-citrate-bile salts-sucrose (TCBS) agar. Where necessary, samples were enriched using alkaline peptone water (APW) for optimum isolation of the targeted Vibrio spp. Presumptive isolates were identified and delineated into the six targeted pathogenic Vibrio spp. using PCR method. The antibiogram fingerprint of selected Vibrio spp. against a panel 18 panels of antibacterial agents were also carried out. Multiple antibiotic resistance phenotypes (MARPs) per set of isolates from water sampling sites and aquatic animal types were determined. Finally, multiple antibiotic resistance indices (MARI) for isolates recovered from the samples were determined. All experiments were done in replicate and data compared using one-way analysis of variance and one-tail t-test as appropriate. Correlation and regression analysis were also carried out as appropriate. Uncontrolled agricultural, industrial and domestic wastewater influxes, as well as run-off intrusions into the water resources investigated, were observed throughout the sampling season. The physicochemical qualities of the water resources varied with seasons. While pH observed for all the water sampling sites complied with South Africa and international standards, most sampling sites did not comply with set standards for one or more of the remaining physicochemical parameters. The parameters that frequently exhibited significant correlation and regression with Vibrio spp. densities were TDS, TSS, turbidity and temperature. The densities of Vibrio spp. in the samples studied varied with season and the highest density per sample types were observed in the summer. The prevalence of Vibrio spp. in freshwater, brackish water and aquatic animal samples were 79 percent, 78 percent and 86 percent respectively. The respective prevalence of V. cholerae, V. mimicus, V. fluvialis, V.alginolyticus, V. vulnificus and V. parahaemolyticus in freshwater samples (18 percent, 3 percent, ~1 percent, ~1 percent, <1 percent, < percent), brackish water(12 percent, 3 percent, 28 percent,~1 percent, ~1 percent, 9 percent) and aquatic animals (9 percent, 1 percent, 17 percent, 1 percent, 1 percent, 17 percent) were observed. All isolates from all the sample types showed very high antibiotic resistance against ampicillin and polymyxin B. Furthermore, MARPs were observed among isolates from the three sample types. Multiple antibiotic resistance indices (MARI) above 0.2 was observed at one site on Kowie River, three on Kubusi River and one on Buffalo River. The findings of this study suggest that most South Africa water-bodies especially freshwater resources are not well protected. This need to be addressed in a country like South Africa where availability of the freshwater resource for human activities is a critical issue. Base on the prevalence of pathogenic Vibrio spp. especially MARPs and sites that exhibited above 0.2 threshold for MARI, environmental base Vibrio species monitoring programs are recommended.
- Full Text:
- Date Issued: 2018
- Authors: Abioye, Oluwatayo Emmanuel
- Date: 2018
- Subjects: Vibrio cholerae -- Pathogens Vibrio cholerae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9154 , vital:34283
- Description: The global socioeconomic and disease burdens of cholera; a disease caused by Vibrio cholerae have been ongoing since it was first reported in India in 1563. Unfortunately, emerging non-cholera causing Vibrio pathogens have been contributing to the malady of Vibrio genus globally in the recent years. The history of cholera outbreaks in South Africa have been well documented but information regarding other non-cholera Vibrio pathogens, is deficient in the literature. This study evaluated the statuses of aquatic animals including crustaceans, molluscs, and fish as important reservoirs of six key pathogenic Vibrio spp. in some important water resources and fish markets in the Eastern Cape, South Africa, between December 2016 and November 2017. Physiochemical parameters that are vital for water quality assessment were determined for all the water sampling points using standard methods. The parameters include pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, temperature, total dissolved solids, turbidity and biological oxygen demand (BOD5). Vibrio spp. densities in water and aquatic animal samples were determined using membrane filtration and Most Probable NumberPolymerase chain reaction (MPN-PCR) methods respectively. Presumptive Vibrio spp. were recovered from the samples by direct plating of water samples and aliquots of aquatic animal homogenates on thiosulfate-citrate-bile salts-sucrose (TCBS) agar. Where necessary, samples were enriched using alkaline peptone water (APW) for optimum isolation of the targeted Vibrio spp. Presumptive isolates were identified and delineated into the six targeted pathogenic Vibrio spp. using PCR method. The antibiogram fingerprint of selected Vibrio spp. against a panel 18 panels of antibacterial agents were also carried out. Multiple antibiotic resistance phenotypes (MARPs) per set of isolates from water sampling sites and aquatic animal types were determined. Finally, multiple antibiotic resistance indices (MARI) for isolates recovered from the samples were determined. All experiments were done in replicate and data compared using one-way analysis of variance and one-tail t-test as appropriate. Correlation and regression analysis were also carried out as appropriate. Uncontrolled agricultural, industrial and domestic wastewater influxes, as well as run-off intrusions into the water resources investigated, were observed throughout the sampling season. The physicochemical qualities of the water resources varied with seasons. While pH observed for all the water sampling sites complied with South Africa and international standards, most sampling sites did not comply with set standards for one or more of the remaining physicochemical parameters. The parameters that frequently exhibited significant correlation and regression with Vibrio spp. densities were TDS, TSS, turbidity and temperature. The densities of Vibrio spp. in the samples studied varied with season and the highest density per sample types were observed in the summer. The prevalence of Vibrio spp. in freshwater, brackish water and aquatic animal samples were 79 percent, 78 percent and 86 percent respectively. The respective prevalence of V. cholerae, V. mimicus, V. fluvialis, V.alginolyticus, V. vulnificus and V. parahaemolyticus in freshwater samples (18 percent, 3 percent, ~1 percent, ~1 percent, <1 percent, < percent), brackish water(12 percent, 3 percent, 28 percent,~1 percent, ~1 percent, 9 percent) and aquatic animals (9 percent, 1 percent, 17 percent, 1 percent, 1 percent, 17 percent) were observed. All isolates from all the sample types showed very high antibiotic resistance against ampicillin and polymyxin B. Furthermore, MARPs were observed among isolates from the three sample types. Multiple antibiotic resistance indices (MARI) above 0.2 was observed at one site on Kowie River, three on Kubusi River and one on Buffalo River. The findings of this study suggest that most South Africa water-bodies especially freshwater resources are not well protected. This need to be addressed in a country like South Africa where availability of the freshwater resource for human activities is a critical issue. Base on the prevalence of pathogenic Vibrio spp. especially MARPs and sites that exhibited above 0.2 threshold for MARI, environmental base Vibrio species monitoring programs are recommended.
- Full Text:
- Date Issued: 2018
Molecularly imprinted polymeric materials for adsorptive removal of nitrogen compounds from fuel oils
- Abdul-Quadir, Muhammad Sabiu
- Authors: Abdul-Quadir, Muhammad Sabiu
- Date: 2018
- Subjects: Polymerization , Organonitrogen compounds Nitrogen compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23426 , vital:30542
- Description: The deleterious effects of refractory polyaromatic hydrocarbons found in fuels such as organonitrogen compounds (quinoline, carbazole and its alkylated derivatives) are such that they emit NOx to the environment when combusted, thereby reducing air quality. These compounds also deactivate the catalyst used during fuel refinement and in catalytic converters of cars. Hydro-denitrogenation (HDN), a process currently being employed in petroleum refineries to eliminate organonitrogen compounds in fuels, is limited in treating these refractory compounds. Hence, this thesis describes the use of two separate complimentary approaches for the removal of organonitrogen compounds in fuel such as oxidative denitrogenation and adsorptive denitrogenation. The catalyzed oxidation of fuel oil model nitrogen containing compound, quinoline to quinoline N-oxide, was conducted under batch and continuous flow microreactor at 70°C by using tert-butylhydroperoxide (t-BuOOH) as oxidant and silica supported V2O5 as catalyst, followed by the selective adsorption of the quinoline N-oxide. An overall conversion of 62% quinoline N-oxide was observed. Quinoline-N-oxide in model fuel was absorbed by employing synthesized molecularly imprinted 2,6-pyridine-polybenzimidazole (2,6-PyPBI) nanofibers, 86% of quinoline-N-oxide was removed to give an adsorption capacity (qe) of 4.8 mg/g. DFT calculations to study the interactions of quinoline-N-oxide vs 2,6-PyPBI indicated that: (i) hydrogen bonding (through amino group of 2,6-PyPBI and oxygen atoms of the quinoline-N-oxide), (ii) pi-pi stacking and (iii) extensive number of van der Waals interactions took place. Several oxygenates from N-compounds were produced, thus, complicating the fuel matrix. Therefore, there is a need to move towards adsorptive denitrogenation. Poly-2-(1H-imidazol-2-yl)-4-phenol (PIMH) imprinted microspheres was prepared by suspension polymerization using 2-(2’-hydroxy-4-ethenylphenyl) imidazole as a functional monomer and ethylene glycol dimethacrylate as a crosslinker in the presence of various organonitrogen compounds (templates) to produce 2-(2’-hydroxy-4-ethenylphenyl) imidazole (PIMH). Imprinted microspheres show selectivity for various target model nitrogen-containing compounds with adsorption capacities of 6.8 ± 0.2 mg/g, 6.3 ± 0.3 mg/g and 5.8 ± 0.3 mg/g for quinoline, pyrimidine and carbazole, respectively. Adsorption selectivity increased in the order of quinoline (αi-r = 136.9) ˃ pyrimidine (αi-r = 126.2) ˃carbazole (αi-r = 86.3), when naphthalene was selected as a reference compound. Though, imprinted microspheres displayed excellent nitrogen compound removal both in model and real fuel, there was a need to improve the adsorbent adsorption capacity for N-compounds in fuel through the fabrication of imprinted nanofibers. Molecularly imprinted poly-2-(1H-imidazol-2-yl)-4-phenol nanofibers was prepared by electrospinning of 2-(2’-hydroxy-4-ethenylphenyl) imidazole (PIMH) in the presence of various organonitrogen compounds. These imprinted nanofibers show selectivity for various target model nitrogen-containing compounds with adsorption capacities of 11.7 ± 0.9 mg/g, 11.9 ± 0.8 mg/g and 11.3 ± 1.1 mg/g for quinoline, pyrimidine and carbazole, respectively. Adsorption selectivity increased in the order of pyrimidine (αi-r = 258.8) ˃ quinoline (αi-r = 235.5) ˃ carbazole (αi-r = 168.2). It further displayed excellent nitrogen removal in real fuel. The use of polybenzimidazole (PBI) nanofibers showed selective adsorption of organonitrogen compounds as imprinted sorbent also displayed high selectivity for their target model nitrogen-containing compounds with adsorption capacities of 11.4 ± 0.4 mg/g, 11.9 ± 0.2 mg/g and 10.9 ± 0.7 mg/g for quinoline, pyrimidine and carbazole respectively. Adsorption selectivity increased in the order of pyrimidine (αi-r = 241.5) ˃ quinoline (αi-r = 237.6) ˃ carbazole (αi-r = 170). Thermodynamic parameters obtained from isothermal titration calorimetry (ITC) revealed that quinoline-PIMH/PBI and pyrimidine-PIMH/PBI interactions are exothermic in nature, while carbazole-PIMH/PBI is endothermic in nature. DFT calculations indicated that π-π interactions/stacking and hydrogen bond interactions took place between N-compounds (carbazole, quinoline and pyrimidine) and adsorbent (PIMH and PBI). A significant reduction in the quantity of nitrogen containing compounds in hydrotreated fuel was observed (peak area reduction) when adsorbents (PIMH and PBI) was employed, however, the complex nature of organonitrogen compounds in fuel complicate the structure/function approach on MIPs for targeting these unwanted compounds.
- Full Text:
- Date Issued: 2018
- Authors: Abdul-Quadir, Muhammad Sabiu
- Date: 2018
- Subjects: Polymerization , Organonitrogen compounds Nitrogen compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23426 , vital:30542
- Description: The deleterious effects of refractory polyaromatic hydrocarbons found in fuels such as organonitrogen compounds (quinoline, carbazole and its alkylated derivatives) are such that they emit NOx to the environment when combusted, thereby reducing air quality. These compounds also deactivate the catalyst used during fuel refinement and in catalytic converters of cars. Hydro-denitrogenation (HDN), a process currently being employed in petroleum refineries to eliminate organonitrogen compounds in fuels, is limited in treating these refractory compounds. Hence, this thesis describes the use of two separate complimentary approaches for the removal of organonitrogen compounds in fuel such as oxidative denitrogenation and adsorptive denitrogenation. The catalyzed oxidation of fuel oil model nitrogen containing compound, quinoline to quinoline N-oxide, was conducted under batch and continuous flow microreactor at 70°C by using tert-butylhydroperoxide (t-BuOOH) as oxidant and silica supported V2O5 as catalyst, followed by the selective adsorption of the quinoline N-oxide. An overall conversion of 62% quinoline N-oxide was observed. Quinoline-N-oxide in model fuel was absorbed by employing synthesized molecularly imprinted 2,6-pyridine-polybenzimidazole (2,6-PyPBI) nanofibers, 86% of quinoline-N-oxide was removed to give an adsorption capacity (qe) of 4.8 mg/g. DFT calculations to study the interactions of quinoline-N-oxide vs 2,6-PyPBI indicated that: (i) hydrogen bonding (through amino group of 2,6-PyPBI and oxygen atoms of the quinoline-N-oxide), (ii) pi-pi stacking and (iii) extensive number of van der Waals interactions took place. Several oxygenates from N-compounds were produced, thus, complicating the fuel matrix. Therefore, there is a need to move towards adsorptive denitrogenation. Poly-2-(1H-imidazol-2-yl)-4-phenol (PIMH) imprinted microspheres was prepared by suspension polymerization using 2-(2’-hydroxy-4-ethenylphenyl) imidazole as a functional monomer and ethylene glycol dimethacrylate as a crosslinker in the presence of various organonitrogen compounds (templates) to produce 2-(2’-hydroxy-4-ethenylphenyl) imidazole (PIMH). Imprinted microspheres show selectivity for various target model nitrogen-containing compounds with adsorption capacities of 6.8 ± 0.2 mg/g, 6.3 ± 0.3 mg/g and 5.8 ± 0.3 mg/g for quinoline, pyrimidine and carbazole, respectively. Adsorption selectivity increased in the order of quinoline (αi-r = 136.9) ˃ pyrimidine (αi-r = 126.2) ˃carbazole (αi-r = 86.3), when naphthalene was selected as a reference compound. Though, imprinted microspheres displayed excellent nitrogen compound removal both in model and real fuel, there was a need to improve the adsorbent adsorption capacity for N-compounds in fuel through the fabrication of imprinted nanofibers. Molecularly imprinted poly-2-(1H-imidazol-2-yl)-4-phenol nanofibers was prepared by electrospinning of 2-(2’-hydroxy-4-ethenylphenyl) imidazole (PIMH) in the presence of various organonitrogen compounds. These imprinted nanofibers show selectivity for various target model nitrogen-containing compounds with adsorption capacities of 11.7 ± 0.9 mg/g, 11.9 ± 0.8 mg/g and 11.3 ± 1.1 mg/g for quinoline, pyrimidine and carbazole, respectively. Adsorption selectivity increased in the order of pyrimidine (αi-r = 258.8) ˃ quinoline (αi-r = 235.5) ˃ carbazole (αi-r = 168.2). It further displayed excellent nitrogen removal in real fuel. The use of polybenzimidazole (PBI) nanofibers showed selective adsorption of organonitrogen compounds as imprinted sorbent also displayed high selectivity for their target model nitrogen-containing compounds with adsorption capacities of 11.4 ± 0.4 mg/g, 11.9 ± 0.2 mg/g and 10.9 ± 0.7 mg/g for quinoline, pyrimidine and carbazole respectively. Adsorption selectivity increased in the order of pyrimidine (αi-r = 241.5) ˃ quinoline (αi-r = 237.6) ˃ carbazole (αi-r = 170). Thermodynamic parameters obtained from isothermal titration calorimetry (ITC) revealed that quinoline-PIMH/PBI and pyrimidine-PIMH/PBI interactions are exothermic in nature, while carbazole-PIMH/PBI is endothermic in nature. DFT calculations indicated that π-π interactions/stacking and hydrogen bond interactions took place between N-compounds (carbazole, quinoline and pyrimidine) and adsorbent (PIMH and PBI). A significant reduction in the quantity of nitrogen containing compounds in hydrotreated fuel was observed (peak area reduction) when adsorbents (PIMH and PBI) was employed, however, the complex nature of organonitrogen compounds in fuel complicate the structure/function approach on MIPs for targeting these unwanted compounds.
- Full Text:
- Date Issued: 2018
Motivation for landscape stewardship as a driver of change-Garden Route, South Africa
- Authors: Heider, Lisa
- Date: 2018
- Subjects: Social ecology , Environmental psychology Conservation (Psychology)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/30116 , vital:30826
- Description: Stewardship, as portrayed in much of contemporary literature is considered as a key to the sustainability challenges of the biosphere. In disciplines which regard sustainability in the context of Social Ecological Systems (SES), stewardship is associated with the goal of building resilience through the informal governance structures that dictate how the landscape is utilized. These disciplines lack a better integration of individual roles and responsibilities as they relate to their daily interactions with the environment. Formally initiated stewardship can evoke maladaptation, in other words the attempts to conserve a specific natural assets in one particular locality can shift the problem of degradation or exploitation to another place or point in time. This is because the individual, as an inevitable driver of unsustainability, has not been addressed. What is needed is the knowledge of strategies which resolve human disconnection from nature and the biosphere, through a greater focus on the individual motivational scale. In Chapter 2, which consists of a literature review of recent stewardship discourses, I extract alternative theories which consider individual motivation and subjectivity as the underlying drivers of resilience. These include knowledge about Sense of Place, and theories from Conservation Psychology. Basic Human Value theory is also presented as a possible entry point for societal transformation through individual motivation. These ought to inform conservation interventions with mechanisms which truly grasp unsustainability at its roots. This is a place-based, qualitative study where the results assist in interrogating the question: How does individual motivation for stewardship mediate socialecological trajectories of change? The context of the study and the methods used to generate my research findings are presented in Chapter 3 and 4. The Garden Route provides the place-based context for this research and is situated in the Western Cape Province of South Africa. The region is home to diverse cultures representative of Western and indigenous regions who meet and negotiate what it means to care for the environment. The area is biologically rich and ecologically highly sensitive to current trajectories of development, fragmentation and global change. Mixed methods and a qualitative approach was used to answer three sub-questions: (1) Which theories facilitate greater understanding of transformative stewardship pathways? (2) How can a transformative pathway be recognized? and (3) How can transformative pathways be pursued? One method used in this study is a photo-voice technique, which is coupled with self-directed journaling and in-depth interviews. Other sources of data include communication and engagement, observations iii and focus groups. I apply a content analysis to the transcribed qualitative data to resolve the research questions. Research results are presented in Chapter 5. In this empirical chapter I present three competing meanings of stewardship and visions for change held by individuals in the Garden Route. The three meanings are described as: protect nature from human influence (Nature despite People); work together and communicate (Nature for People/Nature and People); and be the change you want to see in this world (People in Nature). The variable which best describes the differences in visions is Critical Connectivity. Resilience in a SES is critically dependent on three levels of connectivity in stewardship. Firstly, individuals’ consciousness of being interrelated and interdependent within a community of life; Secondly, expressions in the physical landscape which promote the connectivity of ecological systems as well as the connectivity between people and nature. Thirdly, Connectedness with the Biosphere, which means that the boundaries of the planet and the functioning of the life-supporting earth system are considered in behaviours. I use Basic Human Value theory to test whether it can explain how the differences between and commonalities within the three groups arise. The results support the theory, suggesting that Basic Human Values underlie individual motivation for stewardship. However, inconsistencies and shortcomings of Basic Human Value theory became evident. I identified new values and value combinations which were not made explicit in the framework. These emerged due to my in-depth qualitative approach, as opposed to the common quantitative uses of the framework. The qualitative approach allows for values to emerge inductively and it elicits nuances of individual value interpretations that the definitions of Basic Human Values do not depict. In the second part of the empirical chapter, I present evidence of maladaptive and transformative stewardship pathways in the Garden Route. A maladaptive pathway is one in which individuals’ expression of care for the environment undermines Critical Connectivity and transfers vulnerabilities in the SES. A transformative pathway is one in which individuals pro-actively invest into Critical Connectivity and enhance resilience. The differences in these pathways are directly related to the differences in motivation. iv The findings of this research reveal that stewardship is the act of ‘place creation’ which is motivated by unique and nuanced differences in basic values and individual consciousness. Recognizable features of transformative and maladaptive stewardship pathways are discussed in Chapter 6. I present a conceptual model that critically evaluates stewardship. This model firstly assists researchers and practitioners to become alert to early warning signs of maladaptive pathways. Secondly, it informs them of potential leverage points for interventions which can induce sustainability transformations. I then apply this model to discuss transformative and maladaptive pathways against the backdrop of my findings and the literature. The elements which emerged as critical in this assessment are risk perceptions, stewardship meaning, connectivity with nature, connectedness with the biosphere, relationship with place, sustenance and identity. Different configurations of each indicator help explain the different pathways. Lastly, I discuss the role of Basic Human Values in each of the pathways. I compare how the motivational orientation towards self-enhancement and self-transcendence, or towards openness to change and conservation, play roles in SES resilience. This discussion brings to the surface the fact that transformative stewardship rests on a combination of these four value categories. In contrast, the absence of self-transcendent values and the presence of power, security and conformity underlie the motivation for maladaptation. I leave the reader with suggestions for interventions which have become relevant as a result of my study. Policy, media, conservation agencies and science shape meanings of stewardship, portray social norms and hence must motivate Critical Connectivity. Transformations can be achieved by targeting changes in values which must include autonomy, universalism, benevolence and spirituality. I discuss how policy and planning, communication, marketing and education can lever transformation through mechanisms identified in my research. Chapter 7 concludes this research with a reflective summary of the academic and practical contributions my study has made for stewardship discourses and for the management of SES resilience in local landscapes. I provide recommendations for further research, as they apply to socio-political change in Post-Apartheid South Africa. I end the concluding chapter by encapsulating my research finding in future scenarios for the Garden Route in the face of change, which namely relate to abrupt and uncertain environmental change, immigration, population growth and implications for spatial planning, and the Garden Route Biosphere Reserve. v In Chapter 8, I provide a reflection of this research. This entails foremost a reflection of how I have accounted for four quality criteria in social research, which are namely dependability, credibility, conformability and transferability. I end the chapter with the limitations and outline of scope of my study..
- Full Text:
- Date Issued: 2018
- Authors: Heider, Lisa
- Date: 2018
- Subjects: Social ecology , Environmental psychology Conservation (Psychology)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/30116 , vital:30826
- Description: Stewardship, as portrayed in much of contemporary literature is considered as a key to the sustainability challenges of the biosphere. In disciplines which regard sustainability in the context of Social Ecological Systems (SES), stewardship is associated with the goal of building resilience through the informal governance structures that dictate how the landscape is utilized. These disciplines lack a better integration of individual roles and responsibilities as they relate to their daily interactions with the environment. Formally initiated stewardship can evoke maladaptation, in other words the attempts to conserve a specific natural assets in one particular locality can shift the problem of degradation or exploitation to another place or point in time. This is because the individual, as an inevitable driver of unsustainability, has not been addressed. What is needed is the knowledge of strategies which resolve human disconnection from nature and the biosphere, through a greater focus on the individual motivational scale. In Chapter 2, which consists of a literature review of recent stewardship discourses, I extract alternative theories which consider individual motivation and subjectivity as the underlying drivers of resilience. These include knowledge about Sense of Place, and theories from Conservation Psychology. Basic Human Value theory is also presented as a possible entry point for societal transformation through individual motivation. These ought to inform conservation interventions with mechanisms which truly grasp unsustainability at its roots. This is a place-based, qualitative study where the results assist in interrogating the question: How does individual motivation for stewardship mediate socialecological trajectories of change? The context of the study and the methods used to generate my research findings are presented in Chapter 3 and 4. The Garden Route provides the place-based context for this research and is situated in the Western Cape Province of South Africa. The region is home to diverse cultures representative of Western and indigenous regions who meet and negotiate what it means to care for the environment. The area is biologically rich and ecologically highly sensitive to current trajectories of development, fragmentation and global change. Mixed methods and a qualitative approach was used to answer three sub-questions: (1) Which theories facilitate greater understanding of transformative stewardship pathways? (2) How can a transformative pathway be recognized? and (3) How can transformative pathways be pursued? One method used in this study is a photo-voice technique, which is coupled with self-directed journaling and in-depth interviews. Other sources of data include communication and engagement, observations iii and focus groups. I apply a content analysis to the transcribed qualitative data to resolve the research questions. Research results are presented in Chapter 5. In this empirical chapter I present three competing meanings of stewardship and visions for change held by individuals in the Garden Route. The three meanings are described as: protect nature from human influence (Nature despite People); work together and communicate (Nature for People/Nature and People); and be the change you want to see in this world (People in Nature). The variable which best describes the differences in visions is Critical Connectivity. Resilience in a SES is critically dependent on three levels of connectivity in stewardship. Firstly, individuals’ consciousness of being interrelated and interdependent within a community of life; Secondly, expressions in the physical landscape which promote the connectivity of ecological systems as well as the connectivity between people and nature. Thirdly, Connectedness with the Biosphere, which means that the boundaries of the planet and the functioning of the life-supporting earth system are considered in behaviours. I use Basic Human Value theory to test whether it can explain how the differences between and commonalities within the three groups arise. The results support the theory, suggesting that Basic Human Values underlie individual motivation for stewardship. However, inconsistencies and shortcomings of Basic Human Value theory became evident. I identified new values and value combinations which were not made explicit in the framework. These emerged due to my in-depth qualitative approach, as opposed to the common quantitative uses of the framework. The qualitative approach allows for values to emerge inductively and it elicits nuances of individual value interpretations that the definitions of Basic Human Values do not depict. In the second part of the empirical chapter, I present evidence of maladaptive and transformative stewardship pathways in the Garden Route. A maladaptive pathway is one in which individuals’ expression of care for the environment undermines Critical Connectivity and transfers vulnerabilities in the SES. A transformative pathway is one in which individuals pro-actively invest into Critical Connectivity and enhance resilience. The differences in these pathways are directly related to the differences in motivation. iv The findings of this research reveal that stewardship is the act of ‘place creation’ which is motivated by unique and nuanced differences in basic values and individual consciousness. Recognizable features of transformative and maladaptive stewardship pathways are discussed in Chapter 6. I present a conceptual model that critically evaluates stewardship. This model firstly assists researchers and practitioners to become alert to early warning signs of maladaptive pathways. Secondly, it informs them of potential leverage points for interventions which can induce sustainability transformations. I then apply this model to discuss transformative and maladaptive pathways against the backdrop of my findings and the literature. The elements which emerged as critical in this assessment are risk perceptions, stewardship meaning, connectivity with nature, connectedness with the biosphere, relationship with place, sustenance and identity. Different configurations of each indicator help explain the different pathways. Lastly, I discuss the role of Basic Human Values in each of the pathways. I compare how the motivational orientation towards self-enhancement and self-transcendence, or towards openness to change and conservation, play roles in SES resilience. This discussion brings to the surface the fact that transformative stewardship rests on a combination of these four value categories. In contrast, the absence of self-transcendent values and the presence of power, security and conformity underlie the motivation for maladaptation. I leave the reader with suggestions for interventions which have become relevant as a result of my study. Policy, media, conservation agencies and science shape meanings of stewardship, portray social norms and hence must motivate Critical Connectivity. Transformations can be achieved by targeting changes in values which must include autonomy, universalism, benevolence and spirituality. I discuss how policy and planning, communication, marketing and education can lever transformation through mechanisms identified in my research. Chapter 7 concludes this research with a reflective summary of the academic and practical contributions my study has made for stewardship discourses and for the management of SES resilience in local landscapes. I provide recommendations for further research, as they apply to socio-political change in Post-Apartheid South Africa. I end the concluding chapter by encapsulating my research finding in future scenarios for the Garden Route in the face of change, which namely relate to abrupt and uncertain environmental change, immigration, population growth and implications for spatial planning, and the Garden Route Biosphere Reserve. v In Chapter 8, I provide a reflection of this research. This entails foremost a reflection of how I have accounted for four quality criteria in social research, which are namely dependability, credibility, conformability and transferability. I end the chapter with the limitations and outline of scope of my study..
- Full Text:
- Date Issued: 2018
Movement of coastal fishery species in Southern Africa: research trends, characterisation of behaviours and a case study on fishery implications
- Authors: Maggs, Jade Quinton
- Date: 2018
- Subjects: Fishery management -- Africa, Southern , Fisheries -- Africa, Southern , Fisheries -- Catch effort , Fisheries -- Environmental aspects , Fisheries --Monitoring , Biotelemetry , Sustainable fisheries -- Africa, Southern , Overfishing -- Africa, Southern
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60574 , vital:27798
- Description: Movement of fishes is an integral part of their daily life, but has significant implications for fishery management. As with nearly all coastal countries, South Africa relies on coastal fisheries as a renewable resource, but many stocks have been overexploited for decades. Although it has long been recognised that an understanding of fish movement is necessary for effective management, it is with some difficulty that the subject has been studied in the past. In recent years, however, improvements in technology have provided the means for more in-depth investigations into fish movement. This research has revealed a range of complex movement behaviours. Movement in fishes occurs on a variety of temporal and spatial scales leading to the characteristic patterns of distribution and abundance observed in marine ecosystems. Fishes move nearly constantly in search of food, shelter or reproductive opportunities. Observations of behaviours such as long-term site fidelity, longdistance migration and natal homing are enabling ecologists to understand patterns of distribution and abundance within a species' range. Fish movement around the South African coast has been studied on numerous occasions but this has largely been confined to studies on single species. Movement behaviour of multiple species has been studied, but this has been limited to spatially localised marine protected area research. There has been little attempt in southern Africa to synthesize interspecific movement behaviour over wide spatial scales.Unprecedented concern over the biological effects of overexploitation, together with rapid technological advances in biotelemetry, have provided the impetus for much research, on a global scale, into the movement of marine animals. I reviewed 101 marine and estuarine fish movement studies from southern Africa, published from 1928 to 2014, with the aim of synthesising research trends and findings. Trends showed an increasing emphasis on fish movement research in publications in the sub-tropical and warm-temperate biogeographic regions along the south and east coasts of southern Africa. Although 63% of publications featured only marine studies, research into fine-scale habitat use in estuaries has been on the increase, concomitant with increasing accessibility of biotelemetry. Overall, 26 fish families were identified in the surveyed literature with regionally endemic sparids featuring in 32% of the publications. Ten movement themes were identified in the surveyed literature, including broad-scale movement patterns, which featured in 68% of studies, followed by fine- scale habitat usage (33%) and protected areas (26%). The most prominent phenomenon, emerging from this research, is that of partial migration, which describes the occurrence of resident and migratory behaviour within a coexisting animal population. Substantial progress has also been made in unravelling the complexities of fine-scale movements in marine reserves and habitat usage in estuaries. While this knowledge has enabled more effective management of South Africa's multi-user, multi-species fisheries, focus should now be directed at improving our understanding of the commonalities in movement behaviour, the associated driving forces behind this behaviour and the extent of movement across reserve boundaries. Mark-recapture data, collected over the past 30 years by the Oceanographic Research Institute’s Cooperative Fish Tagging Project (ORICFTP), were used to investigate broad- scale movement patterns of 30 prominent coastal fishery species (Chapter 4). Fishes were tagged with plastic dart tags along the coastline of southern Africa from Angola to Mozambique. This exercise yielded more than 10000 recaptures. The 30 chosen species represented 14 families, although 12 species belonged to a single family (Sparidae). Overall, 67% of recaptures were reported from the original tagging locality and 73% were recorded within 5 km of the tagging locality. The remaining observations extended from 6-3000 km. Movements were assigned to four distance bins (0-5 km, 6-50km, 51-500km and >500 km) and modelled with an ordinal logistic regression. Species, life-stage (juvenile/adult) and time- at-liberty were included as predictor variables. Model coefficients were then included in a cluster analysis, which produced two primary groupings of species (Category I and II), with two sub-groupings (Category IIa and IIb). Category I species were characterised by wide-ranging movements, greatest median recapture length and highest trophic levels. Category II species were characterised by residency, lower median recapture length and lower trophic levels. These findings have implications for fisheries management. Exploitation of resident species may lead to localised depletion, but their diffuse spatial distribution may offer some resilience. In contrast, even localised targeting of migratory species may pose a population level risk if individuals are known to aggregate. Life-cycle diversity or intra-population variability describes the existence of alternative strategies or tactics among coexisting individuals within an animal population (Chapter 5). Partial migration is a specific case of life-cycle diversity where coexisting groups exhibit either resident or migratory (wide-ranging) behaviour within a single population. Mark- recapture data collected under the auspices of the ORICFTP were used to investigate the occurrence and nature of life-cycle diversity in the movement behaviour of five non- diadromous fish species around the coastline of southern Africa. Among the five species were three teleosts (Category I and IIa) and two elasmobranchs (Category I). A fish was considered to have remained resident if recaptured within 0-5 km after 365 days at liberty. A fish was considered to have undertaken a wide-ranging movement if recaptured more than 50 km away from the release site in 365 days or less. A total of 1848 individuals from the five study species were recaptured during the study, of which 73% of the observations were classified as being resident. Binomial logistic regression confirmed that species, life-stage (juvenile/adult) and ecoregion were significant (p < 0.001) predictors of the probability of wide-ranging behaviour. A Gaussian model confirmed that species and ecoregion were also significant (p < 0.001) predictors of direction and distance of wide-ranging movement. However, the direction and distance of wide-ranging movements in juveniles did not differ significantly (p > 0.05) to that of adults. The median growth rate was mostly greater in wide- ranging individuals; however, this was only statistically significant (p < 0.05) in two cases. These findings provide unequivocal evidence of life-cycle diversity in five fish species, with vastly different life-histories. This ecological phenomenon may provide species resilience at the population level and needs to be considered in fisheries management initiatives. The movement of fishes is a fundamental aspect to consider when designing fishery management regimes. Unfortunately, traditional management strategies have often disregarded movement behaviour to the detriment of fish populations (Chapter 6). As a case study, the management of Lichia amia (Category I: wide-ranging) was evaluated in the context of its movement behaviour. Long-term catch-per-unit-effort (CPUE) datasets were examined for three South African recreational fishery sectors. The CPUE was standardised using generalized linear models (delta-Gamma/hurdle approach) to reduce the effect of factors other than abundance. Factors that were available for this purpose were year, month and locality/zone. Year was included in every model as the primary objective was to detect trends in abundance over time. Although standardised CPUE for all sectors showed an overall long-term decline, there was considerable variability in trends between the different recreational sectors and between datasets. Contrasting trends between competitive shore angling and general shore angling datasets were ascribed to hyperstability in competitive CPUE data. Hyperstability in this case was mostly influenced by rapidly improving technology, techniques and communication networks amongst competitive anglers. Month and locality were significant factors explaining the probability of catching L. amia. This suggests that the predictable aggregatory behaviour of this species could further compound the observed CPUE hyperstability. Although the CPUE responded positively for six years after implementation of the first minimum size and bag limits, and for one year after the decommercialisation of the species, these regulations and their amendments failed to arrest a long-term decline in the CPUE despite the ample evidence for hyperstability. It is clear from this case study that the predictable nature of wide-ranging behaviour in L. amia has made the population vulnerable to exploitation. This has led to the demise in the population, which could have been worse if not for the occurrence of intra-population variability in its movement behaviour, which may provide some measure of resilience.
- Full Text:
- Date Issued: 2018
- Authors: Maggs, Jade Quinton
- Date: 2018
- Subjects: Fishery management -- Africa, Southern , Fisheries -- Africa, Southern , Fisheries -- Catch effort , Fisheries -- Environmental aspects , Fisheries --Monitoring , Biotelemetry , Sustainable fisheries -- Africa, Southern , Overfishing -- Africa, Southern
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60574 , vital:27798
- Description: Movement of fishes is an integral part of their daily life, but has significant implications for fishery management. As with nearly all coastal countries, South Africa relies on coastal fisheries as a renewable resource, but many stocks have been overexploited for decades. Although it has long been recognised that an understanding of fish movement is necessary for effective management, it is with some difficulty that the subject has been studied in the past. In recent years, however, improvements in technology have provided the means for more in-depth investigations into fish movement. This research has revealed a range of complex movement behaviours. Movement in fishes occurs on a variety of temporal and spatial scales leading to the characteristic patterns of distribution and abundance observed in marine ecosystems. Fishes move nearly constantly in search of food, shelter or reproductive opportunities. Observations of behaviours such as long-term site fidelity, longdistance migration and natal homing are enabling ecologists to understand patterns of distribution and abundance within a species' range. Fish movement around the South African coast has been studied on numerous occasions but this has largely been confined to studies on single species. Movement behaviour of multiple species has been studied, but this has been limited to spatially localised marine protected area research. There has been little attempt in southern Africa to synthesize interspecific movement behaviour over wide spatial scales.Unprecedented concern over the biological effects of overexploitation, together with rapid technological advances in biotelemetry, have provided the impetus for much research, on a global scale, into the movement of marine animals. I reviewed 101 marine and estuarine fish movement studies from southern Africa, published from 1928 to 2014, with the aim of synthesising research trends and findings. Trends showed an increasing emphasis on fish movement research in publications in the sub-tropical and warm-temperate biogeographic regions along the south and east coasts of southern Africa. Although 63% of publications featured only marine studies, research into fine-scale habitat use in estuaries has been on the increase, concomitant with increasing accessibility of biotelemetry. Overall, 26 fish families were identified in the surveyed literature with regionally endemic sparids featuring in 32% of the publications. Ten movement themes were identified in the surveyed literature, including broad-scale movement patterns, which featured in 68% of studies, followed by fine- scale habitat usage (33%) and protected areas (26%). The most prominent phenomenon, emerging from this research, is that of partial migration, which describes the occurrence of resident and migratory behaviour within a coexisting animal population. Substantial progress has also been made in unravelling the complexities of fine-scale movements in marine reserves and habitat usage in estuaries. While this knowledge has enabled more effective management of South Africa's multi-user, multi-species fisheries, focus should now be directed at improving our understanding of the commonalities in movement behaviour, the associated driving forces behind this behaviour and the extent of movement across reserve boundaries. Mark-recapture data, collected over the past 30 years by the Oceanographic Research Institute’s Cooperative Fish Tagging Project (ORICFTP), were used to investigate broad- scale movement patterns of 30 prominent coastal fishery species (Chapter 4). Fishes were tagged with plastic dart tags along the coastline of southern Africa from Angola to Mozambique. This exercise yielded more than 10000 recaptures. The 30 chosen species represented 14 families, although 12 species belonged to a single family (Sparidae). Overall, 67% of recaptures were reported from the original tagging locality and 73% were recorded within 5 km of the tagging locality. The remaining observations extended from 6-3000 km. Movements were assigned to four distance bins (0-5 km, 6-50km, 51-500km and >500 km) and modelled with an ordinal logistic regression. Species, life-stage (juvenile/adult) and time- at-liberty were included as predictor variables. Model coefficients were then included in a cluster analysis, which produced two primary groupings of species (Category I and II), with two sub-groupings (Category IIa and IIb). Category I species were characterised by wide-ranging movements, greatest median recapture length and highest trophic levels. Category II species were characterised by residency, lower median recapture length and lower trophic levels. These findings have implications for fisheries management. Exploitation of resident species may lead to localised depletion, but their diffuse spatial distribution may offer some resilience. In contrast, even localised targeting of migratory species may pose a population level risk if individuals are known to aggregate. Life-cycle diversity or intra-population variability describes the existence of alternative strategies or tactics among coexisting individuals within an animal population (Chapter 5). Partial migration is a specific case of life-cycle diversity where coexisting groups exhibit either resident or migratory (wide-ranging) behaviour within a single population. Mark- recapture data collected under the auspices of the ORICFTP were used to investigate the occurrence and nature of life-cycle diversity in the movement behaviour of five non- diadromous fish species around the coastline of southern Africa. Among the five species were three teleosts (Category I and IIa) and two elasmobranchs (Category I). A fish was considered to have remained resident if recaptured within 0-5 km after 365 days at liberty. A fish was considered to have undertaken a wide-ranging movement if recaptured more than 50 km away from the release site in 365 days or less. A total of 1848 individuals from the five study species were recaptured during the study, of which 73% of the observations were classified as being resident. Binomial logistic regression confirmed that species, life-stage (juvenile/adult) and ecoregion were significant (p < 0.001) predictors of the probability of wide-ranging behaviour. A Gaussian model confirmed that species and ecoregion were also significant (p < 0.001) predictors of direction and distance of wide-ranging movement. However, the direction and distance of wide-ranging movements in juveniles did not differ significantly (p > 0.05) to that of adults. The median growth rate was mostly greater in wide- ranging individuals; however, this was only statistically significant (p < 0.05) in two cases. These findings provide unequivocal evidence of life-cycle diversity in five fish species, with vastly different life-histories. This ecological phenomenon may provide species resilience at the population level and needs to be considered in fisheries management initiatives. The movement of fishes is a fundamental aspect to consider when designing fishery management regimes. Unfortunately, traditional management strategies have often disregarded movement behaviour to the detriment of fish populations (Chapter 6). As a case study, the management of Lichia amia (Category I: wide-ranging) was evaluated in the context of its movement behaviour. Long-term catch-per-unit-effort (CPUE) datasets were examined for three South African recreational fishery sectors. The CPUE was standardised using generalized linear models (delta-Gamma/hurdle approach) to reduce the effect of factors other than abundance. Factors that were available for this purpose were year, month and locality/zone. Year was included in every model as the primary objective was to detect trends in abundance over time. Although standardised CPUE for all sectors showed an overall long-term decline, there was considerable variability in trends between the different recreational sectors and between datasets. Contrasting trends between competitive shore angling and general shore angling datasets were ascribed to hyperstability in competitive CPUE data. Hyperstability in this case was mostly influenced by rapidly improving technology, techniques and communication networks amongst competitive anglers. Month and locality were significant factors explaining the probability of catching L. amia. This suggests that the predictable aggregatory behaviour of this species could further compound the observed CPUE hyperstability. Although the CPUE responded positively for six years after implementation of the first minimum size and bag limits, and for one year after the decommercialisation of the species, these regulations and their amendments failed to arrest a long-term decline in the CPUE despite the ample evidence for hyperstability. It is clear from this case study that the predictable nature of wide-ranging behaviour in L. amia has made the population vulnerable to exploitation. This has led to the demise in the population, which could have been worse if not for the occurrence of intra-population variability in its movement behaviour, which may provide some measure of resilience.
- Full Text:
- Date Issued: 2018
Naming in Germany in the 20th century: a sociological study of naming in times of social change, with a focus on statistical problems in empirical onomastic research
- Authors: Huschka, Denis
- Date: 2018
- Subjects: Onomastics , Names, Personal -- Germany , Names, German -- Etymology , Names, German -- Social aspects , German language -- Etymology -- Names , German Socio Economic Panel Study (SOEP)
- Language: German , English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63054 , vital:28359
- Description: In this thesis names are used as social indicators to observe social change in Germany in the 20th century. The German Socio Economic Panel Study (SOEP) offers the rare opportunity to analyse representative survey data of first names. The empirical results of the analyses in this thesis offer a comprehensive picture on how the naming reality in Germany looks like and how naming changed in a period of about 100 years. Names can serve as social indicators. It is demonstrated how chosen names mirror social change in the German society: Name choices have become less traditional and more individual. Over time names from other world regions and cultures have found their way into the German culture. There are more different names in use today than 100 years ago and the names have become more evenly distributed over the population. Today children are less likely to share their names with many of their peers. These are signs of an increasingly individualised, transnationalised modern behaviour of the people in contemporary Germany. Almost all of these developments started earlier and tend to be more pronounced for girl’s names. The secularisation of the German society - however - did not cause substantial changes in naming over time. Christian names still are used to the greatest extent, but – possibly – not because they are regarded as being of Christian origin. The analyses of the social-structural influences on naming touch on some effects of education and status. The analyses of differences in naming between the two German states during the time of division adds some evidence to the real-life experience that naming in the communist East Germany was much more oriented towards the free western hemisphere – a kind of silent protest. Obviously naming was a possibility to distance oneself from an un-loved regime. On a methodological level referring to onomastics, the so-called „Large Number of are Events-Zone (LNRE)“, a feature of the distribution of names that has mostly been handled inappropriately up to now, is discussed with respect to its effects on name statistics when using samples. An alternative approach is proposed for the appropriate handling of this feature. , In der vorliegenden Arbeit werden Vornamen als soziale Indikatoren benutzt, um gesellschaftlichen Wandel im 20. Jahrhundert zu beschreiben. Das Soziooekonomische Panel (SOEP) bietet die seltene Möglichkeit, Umfragedaten über die Vornamen der Deutschen repräsentativ auszuwerten. Die empirischen Ergebnisse der vorliegenden Arbeit bieten einen umfassenden Einblick in die deutsche Vornamensrealität und über die Entwicklungen der Namensvergabe in 100 Jahren. Namen sind soziale Indikatoren. Es wird aufgezeigt, wie die Namensgebung den sozialen Wandel in der deutschen Gesellschaft spiegelt: Namenwahlen weisen über die Zeit weniger traditionelle Bezüge auf, sie wurden individueller. Namen aus anderen Kulturen und Ländern fanden Eingang in die deutsche Kultur. Es werden mehr verschiedene Namen benutzt als vor 100 Jahren und die typischerweise hoch konzentrierten Verteilungen der Vornamen stellen sich über die Zeit etwas weniger konzentriert dar. Heute geborene Kinder teilen ihre Namen mit anteilig weniger anderen Kindern ihrer Kohorte. Dies sind Anzeichen für eine individualisierte, transnational orientierte moderne Gesellschaft. Fast alle dieser Entwicklungen sind für Mädchennamen früher und in deutlicherem Maße zu beobachten. Die Säkularisierung der deutschen Gesellschaft hat hingegen wenig Einfluss auf die Vornamenswahlen genommen. Nach wie vor werden vor allem christliche Namen vergeben, auch wenn der christliche Bezug unter Umständen nicht mehr der maßgebliche Grund für die Auswahl ist. Die Analyse der sozialstrukturellen Einflüsse auf Namenswahlen bestätigt einige Effekte von Bildung und Status der Mütter. Die Analyse der Unterschiede in der Namensgebung der beiden deutschen Staaten während der 40 jährigen Teilung zeigt, dass der lebensweltliche Eindruck einer zunehmenden West-Orientierung der Namenswahlen ostdeutscher Eltern nicht trügt. Offenbar waren westliche Namen eine Möglichkeit, sich vom ungeliebten Regime zu distanzieren. Auf einer statistisch-methodischen Ebene wird eine bislang in der empirischen Onomastik unrichtig gehandhabte Besonderheit von Vornamensverteilungen – die Large Number of Rare Events-Zone (LNRE) – diskutiert und Lösungsvorschläge für den statistisch korrekten Umgang mit dieser Besonderheit in Gruppenvergleichen auf der Basis von Stichproben vorgelegt.
- Full Text:
- Date Issued: 2018
- Authors: Huschka, Denis
- Date: 2018
- Subjects: Onomastics , Names, Personal -- Germany , Names, German -- Etymology , Names, German -- Social aspects , German language -- Etymology -- Names , German Socio Economic Panel Study (SOEP)
- Language: German , English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63054 , vital:28359
- Description: In this thesis names are used as social indicators to observe social change in Germany in the 20th century. The German Socio Economic Panel Study (SOEP) offers the rare opportunity to analyse representative survey data of first names. The empirical results of the analyses in this thesis offer a comprehensive picture on how the naming reality in Germany looks like and how naming changed in a period of about 100 years. Names can serve as social indicators. It is demonstrated how chosen names mirror social change in the German society: Name choices have become less traditional and more individual. Over time names from other world regions and cultures have found their way into the German culture. There are more different names in use today than 100 years ago and the names have become more evenly distributed over the population. Today children are less likely to share their names with many of their peers. These are signs of an increasingly individualised, transnationalised modern behaviour of the people in contemporary Germany. Almost all of these developments started earlier and tend to be more pronounced for girl’s names. The secularisation of the German society - however - did not cause substantial changes in naming over time. Christian names still are used to the greatest extent, but – possibly – not because they are regarded as being of Christian origin. The analyses of the social-structural influences on naming touch on some effects of education and status. The analyses of differences in naming between the two German states during the time of division adds some evidence to the real-life experience that naming in the communist East Germany was much more oriented towards the free western hemisphere – a kind of silent protest. Obviously naming was a possibility to distance oneself from an un-loved regime. On a methodological level referring to onomastics, the so-called „Large Number of are Events-Zone (LNRE)“, a feature of the distribution of names that has mostly been handled inappropriately up to now, is discussed with respect to its effects on name statistics when using samples. An alternative approach is proposed for the appropriate handling of this feature. , In der vorliegenden Arbeit werden Vornamen als soziale Indikatoren benutzt, um gesellschaftlichen Wandel im 20. Jahrhundert zu beschreiben. Das Soziooekonomische Panel (SOEP) bietet die seltene Möglichkeit, Umfragedaten über die Vornamen der Deutschen repräsentativ auszuwerten. Die empirischen Ergebnisse der vorliegenden Arbeit bieten einen umfassenden Einblick in die deutsche Vornamensrealität und über die Entwicklungen der Namensvergabe in 100 Jahren. Namen sind soziale Indikatoren. Es wird aufgezeigt, wie die Namensgebung den sozialen Wandel in der deutschen Gesellschaft spiegelt: Namenwahlen weisen über die Zeit weniger traditionelle Bezüge auf, sie wurden individueller. Namen aus anderen Kulturen und Ländern fanden Eingang in die deutsche Kultur. Es werden mehr verschiedene Namen benutzt als vor 100 Jahren und die typischerweise hoch konzentrierten Verteilungen der Vornamen stellen sich über die Zeit etwas weniger konzentriert dar. Heute geborene Kinder teilen ihre Namen mit anteilig weniger anderen Kindern ihrer Kohorte. Dies sind Anzeichen für eine individualisierte, transnational orientierte moderne Gesellschaft. Fast alle dieser Entwicklungen sind für Mädchennamen früher und in deutlicherem Maße zu beobachten. Die Säkularisierung der deutschen Gesellschaft hat hingegen wenig Einfluss auf die Vornamenswahlen genommen. Nach wie vor werden vor allem christliche Namen vergeben, auch wenn der christliche Bezug unter Umständen nicht mehr der maßgebliche Grund für die Auswahl ist. Die Analyse der sozialstrukturellen Einflüsse auf Namenswahlen bestätigt einige Effekte von Bildung und Status der Mütter. Die Analyse der Unterschiede in der Namensgebung der beiden deutschen Staaten während der 40 jährigen Teilung zeigt, dass der lebensweltliche Eindruck einer zunehmenden West-Orientierung der Namenswahlen ostdeutscher Eltern nicht trügt. Offenbar waren westliche Namen eine Möglichkeit, sich vom ungeliebten Regime zu distanzieren. Auf einer statistisch-methodischen Ebene wird eine bislang in der empirischen Onomastik unrichtig gehandhabte Besonderheit von Vornamensverteilungen – die Large Number of Rare Events-Zone (LNRE) – diskutiert und Lösungsvorschläge für den statistisch korrekten Umgang mit dieser Besonderheit in Gruppenvergleichen auf der Basis von Stichproben vorgelegt.
- Full Text:
- Date Issued: 2018
Narcissistic defenses and alienation in the life of Howard Hughes: a case study
- Authors: Sandison, Alida
- Date: 2018
- Subjects: Hughes, Howard -- 1905-1976 , Narcissism Self psychology Personality disorders
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/35038 , vital:33609
- Description: Narcissism is a personality configuration which has both normal and pathological personality expressions. It is associated with a very broad field of literature and theoretical formulations, put forward to understand it. To add to this knowledge base, the aim of the research was to explore and describe narcissistic defenses and the consequent alienation of others within the narcissistic personality configuration. The aim was attained through the exploration of the life of Howard Hughes, by examining the interplay between Kernberg’s Object Relations Theory (1974; 1975; 1976; 1980; 1984; 1992; 2001) and Hughes’s lived experiences. Hughes was chosen as the subject as he is renowned for being an eccentric billionaire who was revolutionary in his effect on the world, but concurrently disturbed within his personal pathologies. The study took the form of a case study. Data was collected using Yin’s (1994) guidelines for data collection, which include using multiple sources of evidence, creating a case study database, and keeping and maintaining a reliable chain of evidence. Data was furthermore collected and analysed using Miles and Huberman’s (1994) strategy of data analysis which consists of three steps, namely data reduction, data display, and conclusion drawing and verification. Research findings confirmed the presence of primitive defense mechanisms associated with the lower level pathologies described by Kernberg within Hughes’ patterns. Findings confirmed the defense mechanisms as alienating others. Learnings produced were presented in a model to be used in clinical practice to support others in interaction with narcissistic individuals. Steps outlined included, understand, decontaminate and reconstruct, reaffirm reality, and find something positive.
- Full Text:
- Date Issued: 2018
- Authors: Sandison, Alida
- Date: 2018
- Subjects: Hughes, Howard -- 1905-1976 , Narcissism Self psychology Personality disorders
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/35038 , vital:33609
- Description: Narcissism is a personality configuration which has both normal and pathological personality expressions. It is associated with a very broad field of literature and theoretical formulations, put forward to understand it. To add to this knowledge base, the aim of the research was to explore and describe narcissistic defenses and the consequent alienation of others within the narcissistic personality configuration. The aim was attained through the exploration of the life of Howard Hughes, by examining the interplay between Kernberg’s Object Relations Theory (1974; 1975; 1976; 1980; 1984; 1992; 2001) and Hughes’s lived experiences. Hughes was chosen as the subject as he is renowned for being an eccentric billionaire who was revolutionary in his effect on the world, but concurrently disturbed within his personal pathologies. The study took the form of a case study. Data was collected using Yin’s (1994) guidelines for data collection, which include using multiple sources of evidence, creating a case study database, and keeping and maintaining a reliable chain of evidence. Data was furthermore collected and analysed using Miles and Huberman’s (1994) strategy of data analysis which consists of three steps, namely data reduction, data display, and conclusion drawing and verification. Research findings confirmed the presence of primitive defense mechanisms associated with the lower level pathologies described by Kernberg within Hughes’ patterns. Findings confirmed the defense mechanisms as alienating others. Learnings produced were presented in a model to be used in clinical practice to support others in interaction with narcissistic individuals. Steps outlined included, understand, decontaminate and reconstruct, reaffirm reality, and find something positive.
- Full Text:
- Date Issued: 2018
Narrated experiences of the pre-termination of pregnancy counselling healthcare encounter in the Eastern Cape public health sector
- Mavuso, Jabulile Mary-Jane Jace
- Authors: Mavuso, Jabulile Mary-Jane Jace
- Date: 2018
- Subjects: Abortion counseling -- South Africa -- Eastern Cape , Abortion -- Psychological aspects , Abortion -- Social aspects , Pro-choice movement -- South Africa -- Eastern Cape , Reproductive rights -- South Africa -- Eastern Cape , Women -- Sexual behavior -- South Africa -- Eastern Cape , Women -- South Africa -- Social conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62928 , vital:28311
- Description: Research that has been conducted about experiences of pre-abortion counselling tends to investigate either womxn's1 or healthcare providers' experiences separately, with research on womxn's experiences of abortion and abortion counselling dominating this area of research. Although some of the studies on womxn's abortion experiences have explored womxn's experiences of interactions between themselves and healthcare providers, these aspects have been underreported. To my knowledge, research that also explores womxn's interactions among themselves in the waiting room has not been done. Furthermore, research that explores the pre-termination of pregnancy healthcare encounter, where womxn's and healthcare providers' experiences of waiting room interactions and of pre-abortion counselling practices are seen as interrelated, has not been conducted. Research that has been conducted among womxn's experiences show that womxn have varying experiences of pre-abortion counselling, with some finding it useful while other womxn have found it to be lacking in relevance to their specific situation or needs. Research conducted among healthcare providers also points to varying experiences, with some healthcare providers stratifying womxn's reasons for abortion according to the acceptability of the request. This study explores health service providers’ and womxn’s narrated experiences of the pre-termination of pregnancy healthcare encounter (waiting room interactions and pre-abortion counselling) in the Eastern Cape public health sector. An African feminist post-structural approach, which enables analysis of how discursive structures and power relations may underpin African womxn's experiences of oppression and resistance, was used. Fusing this approach with a narrative-discursive analysis, enabled an exploration of the discursive resources drawn upon and the power relations referred to by participants when constructing micro-narratives and accounts of their experiences of waiting room interactions and pre-abortion counselling practices. This fusion enabled an understanding of the micro (individual) and macro (social) and how they interact and come to bear on experiences of the pre-abortion counselling healthcare encounter. Womxn's micro-narratives and healthcare providers' accounts were compared for convergences and divergences in the pre-abortion counselling practices they described. The implications of these convergences and divergences and of the power relations referred to by participants for pre-abortion counselling service provision are discussed. The research referred to in this study were conducted in contexts where abortion is legal, although the conditions under which it may be accessed differ across and within contexts. This present study is contextualised by the Choice on Termination of Pregnancy Act No. 92 of 1996 which legalises abortion and stipulates that abortion counselling should be made available to womxn but should be non-mandatory and non-directive. Data were collected at three abortion facilities located in public hospitals in the Eastern Cape. Open-ended, semi-structured interviews were conducted with 30 womxn after they received pre-abortion counselling, and four healthcare providers involved in abortion service provision. Data were analysed using an extended narrative-discursive approach which entailed exploring patterns in and across participants' talk. These patterns took the form of discursive resources (discourses and the subject positions they made available, and canonical narratives), power relations, and micro-narratives and accounts of their experiences of pre-abortion counselling practices and waiting room interactions. Participants described the following pre-abortion counselling practices: information-giving practices, consent practices, administering of LARCs, a waiting period and third-party involvement. In describing these processes, participants drew on an awfulisation of abortion discourse, moralising discourses, pronatalist discourses, and liberal discourses to construct (micro-)narratives in which liberal, pastoral and authoritarian counselling practices and power relations were constructed and referred to. In their micro-narratives, most womxn described the counselling as informative, beneficial and healing whilst also describing shock, hurt, pain and distress at the various kinds of information they received. Healthcare providers drew on discourses and canonical narratives (such as the hero and personal testimony) to justify liberal, pastoral and authoritarian counselling practices which were underpinned by constructing abortion and unintended pregnancy as problematic. The pre-abortion counselling practices that were described were directive in two ways: the coercion of contraceptive uptake post-abortion, and information provision practices which effectively work to delegitimise and persuade womxn against abortion.
- Full Text:
- Date Issued: 2018
- Authors: Mavuso, Jabulile Mary-Jane Jace
- Date: 2018
- Subjects: Abortion counseling -- South Africa -- Eastern Cape , Abortion -- Psychological aspects , Abortion -- Social aspects , Pro-choice movement -- South Africa -- Eastern Cape , Reproductive rights -- South Africa -- Eastern Cape , Women -- Sexual behavior -- South Africa -- Eastern Cape , Women -- South Africa -- Social conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62928 , vital:28311
- Description: Research that has been conducted about experiences of pre-abortion counselling tends to investigate either womxn's1 or healthcare providers' experiences separately, with research on womxn's experiences of abortion and abortion counselling dominating this area of research. Although some of the studies on womxn's abortion experiences have explored womxn's experiences of interactions between themselves and healthcare providers, these aspects have been underreported. To my knowledge, research that also explores womxn's interactions among themselves in the waiting room has not been done. Furthermore, research that explores the pre-termination of pregnancy healthcare encounter, where womxn's and healthcare providers' experiences of waiting room interactions and of pre-abortion counselling practices are seen as interrelated, has not been conducted. Research that has been conducted among womxn's experiences show that womxn have varying experiences of pre-abortion counselling, with some finding it useful while other womxn have found it to be lacking in relevance to their specific situation or needs. Research conducted among healthcare providers also points to varying experiences, with some healthcare providers stratifying womxn's reasons for abortion according to the acceptability of the request. This study explores health service providers’ and womxn’s narrated experiences of the pre-termination of pregnancy healthcare encounter (waiting room interactions and pre-abortion counselling) in the Eastern Cape public health sector. An African feminist post-structural approach, which enables analysis of how discursive structures and power relations may underpin African womxn's experiences of oppression and resistance, was used. Fusing this approach with a narrative-discursive analysis, enabled an exploration of the discursive resources drawn upon and the power relations referred to by participants when constructing micro-narratives and accounts of their experiences of waiting room interactions and pre-abortion counselling practices. This fusion enabled an understanding of the micro (individual) and macro (social) and how they interact and come to bear on experiences of the pre-abortion counselling healthcare encounter. Womxn's micro-narratives and healthcare providers' accounts were compared for convergences and divergences in the pre-abortion counselling practices they described. The implications of these convergences and divergences and of the power relations referred to by participants for pre-abortion counselling service provision are discussed. The research referred to in this study were conducted in contexts where abortion is legal, although the conditions under which it may be accessed differ across and within contexts. This present study is contextualised by the Choice on Termination of Pregnancy Act No. 92 of 1996 which legalises abortion and stipulates that abortion counselling should be made available to womxn but should be non-mandatory and non-directive. Data were collected at three abortion facilities located in public hospitals in the Eastern Cape. Open-ended, semi-structured interviews were conducted with 30 womxn after they received pre-abortion counselling, and four healthcare providers involved in abortion service provision. Data were analysed using an extended narrative-discursive approach which entailed exploring patterns in and across participants' talk. These patterns took the form of discursive resources (discourses and the subject positions they made available, and canonical narratives), power relations, and micro-narratives and accounts of their experiences of pre-abortion counselling practices and waiting room interactions. Participants described the following pre-abortion counselling practices: information-giving practices, consent practices, administering of LARCs, a waiting period and third-party involvement. In describing these processes, participants drew on an awfulisation of abortion discourse, moralising discourses, pronatalist discourses, and liberal discourses to construct (micro-)narratives in which liberal, pastoral and authoritarian counselling practices and power relations were constructed and referred to. In their micro-narratives, most womxn described the counselling as informative, beneficial and healing whilst also describing shock, hurt, pain and distress at the various kinds of information they received. Healthcare providers drew on discourses and canonical narratives (such as the hero and personal testimony) to justify liberal, pastoral and authoritarian counselling practices which were underpinned by constructing abortion and unintended pregnancy as problematic. The pre-abortion counselling practices that were described were directive in two ways: the coercion of contraceptive uptake post-abortion, and information provision practices which effectively work to delegitimise and persuade womxn against abortion.
- Full Text:
- Date Issued: 2018
Non-farm enterprises and rural development in South Africa : a case of the Eastern Cape
- Authors: Dapira, Clarah
- Date: 2018
- Subjects: Rural development--South Africa--Eastern Cape--Case studies Rural development--South Africa South Africa--Economic conditions
- Language: English
- Type: Thesis , Doctoral , Development Studies
- Identifier: http://hdl.handle.net/10353/15463 , vital:40410
- Description: There is growing recognition that the limited success in rural development policies in many developing countries, including South Africa, is mainly a result of the failure to conceptualize such interventions beyond agriculture and incorporate non-farm enterprises into the mix. Non-farm enterprises are increasingly viewed as having the potential to become one of the drivers of rural development. However, it is an area that remains poorly documented and dimly understood as it has received limited scholarly attention in recent years. The study was carried out in the rural areas of Port St John’s Local Municipality in the Eastern Cape Province of South Africa. The study was premised on the assumption that non-farm enterprises have the potential to become one of the drivers of rural development in terms of employment creation, income generation and diversification of the rural economy. The thesis demonstrates that the hope that non-farm enterprises can add value to the rural economy in terms of creating the much needed employment opportunities is still a goal to be realised. Nevertheless, the income generated by these enterprises is contributing immensely to household welfare, especially improving accessibility to food by poor households. The study recommends the implementation of tailor made capacity building and training programmes aimed at enhancing the skills of rural artisans. This is an area that requires state-mediated intervention to augment the rural economy in order to redress the uneven development of the past.
- Full Text:
- Date Issued: 2018
- Authors: Dapira, Clarah
- Date: 2018
- Subjects: Rural development--South Africa--Eastern Cape--Case studies Rural development--South Africa South Africa--Economic conditions
- Language: English
- Type: Thesis , Doctoral , Development Studies
- Identifier: http://hdl.handle.net/10353/15463 , vital:40410
- Description: There is growing recognition that the limited success in rural development policies in many developing countries, including South Africa, is mainly a result of the failure to conceptualize such interventions beyond agriculture and incorporate non-farm enterprises into the mix. Non-farm enterprises are increasingly viewed as having the potential to become one of the drivers of rural development. However, it is an area that remains poorly documented and dimly understood as it has received limited scholarly attention in recent years. The study was carried out in the rural areas of Port St John’s Local Municipality in the Eastern Cape Province of South Africa. The study was premised on the assumption that non-farm enterprises have the potential to become one of the drivers of rural development in terms of employment creation, income generation and diversification of the rural economy. The thesis demonstrates that the hope that non-farm enterprises can add value to the rural economy in terms of creating the much needed employment opportunities is still a goal to be realised. Nevertheless, the income generated by these enterprises is contributing immensely to household welfare, especially improving accessibility to food by poor households. The study recommends the implementation of tailor made capacity building and training programmes aimed at enhancing the skills of rural artisans. This is an area that requires state-mediated intervention to augment the rural economy in order to redress the uneven development of the past.
- Full Text:
- Date Issued: 2018
On high-altitude and high- latitude frost environments
- Authors: Hansen, Christel Dorothee
- Date: 2018
- Subjects: Frost -- Drakensberg Mountains , Frost -- Prince Edward Islands -- Marion Island , Frost -- Antarctica -- Queen Maud Land , Climatic geomorphology -- Southern Hemisphere , Permafrost -- Southern Hemisphere , Periglacial processes -- Southern Hemisphere , Frost environments -- Southern Hemisphere
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62383 , vital:28169
- Description: Frost environments occur throughout the world, with associated processes occurring across climatic zones. Climatic geomorphology proposes that climatic zones, largely derived from annual average air temperature and precipitation values, have specific landforms and processes active within that zone. This study offers unique insights into the frost environments of three locations in the Southern Hemisphere, namely the Eastern Cape Drakensberg of South Africa, sub-Antarctic Marion Island, and Dronning Maud Land of Antarctica. The Drakensberg ranges from temperate to alpine, Marion Island is hyper-maritime, and Dronning Maud Land a polar desert. Drivers and forcings on the ground frost regime are identified, as are future climatic scenarios. Altitude and latitude were identified as the most important locational drivers, while air temperature showed highest correlation with freezing events. The initiation of a freeze event correlated strongly with maximum ground temperatures. Vegetation cover was found to ameliorate frost cycles, thereby increasing ground temperatures. Dronning Maud Land of Antarctica is characterised by annual frost (permafrost), with limited seasonal thaw in summer. Thawing cycles reflected the depth of the active layer, which ranged from just under 60 cm for Robertskollen (at lowest altitude) to less than 15 cm on Slettfjell (at greatest altitude). Marion Island had the most active frost environment, exhibiting both seasonal frost, and ubiquitous shallow diurnal frost cycles. The Drakensberg were largely frost-free, with limited seasonal frost and few diurnal freeze- thaw events. Diurnal frost processes were found to be azonal, and present at all three study locations. Evidence of landforms derived from diurnal frost processes were evident in each zone. Equifinality/convergence of form was present to a degree. The presence of patterned ground, which was not wholly derived from frost processes, suggests a measure of equifinality. Furthermore, openwork block deposits, of which not all are either blockstreams nor blockfields, are not necessarily the result of frost processes. The periglacial environment is poorly defined and methods to delineate this environment, as well as other climatic zones, should include additional parameters. Delineating zones on annual (and limited) monthly averages based on predominantly temperature, is not sufficient. While concepts of climatic geomorphology may be applied in a general sense, this framework is not suited to working at smaller scales. Specifically, periglacial environments should be delineated using ground moisture, as well as air temperature. Furthermore, vegetation and snow cover are important, as are soil textural properties.
- Full Text:
- Date Issued: 2018
- Authors: Hansen, Christel Dorothee
- Date: 2018
- Subjects: Frost -- Drakensberg Mountains , Frost -- Prince Edward Islands -- Marion Island , Frost -- Antarctica -- Queen Maud Land , Climatic geomorphology -- Southern Hemisphere , Permafrost -- Southern Hemisphere , Periglacial processes -- Southern Hemisphere , Frost environments -- Southern Hemisphere
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62383 , vital:28169
- Description: Frost environments occur throughout the world, with associated processes occurring across climatic zones. Climatic geomorphology proposes that climatic zones, largely derived from annual average air temperature and precipitation values, have specific landforms and processes active within that zone. This study offers unique insights into the frost environments of three locations in the Southern Hemisphere, namely the Eastern Cape Drakensberg of South Africa, sub-Antarctic Marion Island, and Dronning Maud Land of Antarctica. The Drakensberg ranges from temperate to alpine, Marion Island is hyper-maritime, and Dronning Maud Land a polar desert. Drivers and forcings on the ground frost regime are identified, as are future climatic scenarios. Altitude and latitude were identified as the most important locational drivers, while air temperature showed highest correlation with freezing events. The initiation of a freeze event correlated strongly with maximum ground temperatures. Vegetation cover was found to ameliorate frost cycles, thereby increasing ground temperatures. Dronning Maud Land of Antarctica is characterised by annual frost (permafrost), with limited seasonal thaw in summer. Thawing cycles reflected the depth of the active layer, which ranged from just under 60 cm for Robertskollen (at lowest altitude) to less than 15 cm on Slettfjell (at greatest altitude). Marion Island had the most active frost environment, exhibiting both seasonal frost, and ubiquitous shallow diurnal frost cycles. The Drakensberg were largely frost-free, with limited seasonal frost and few diurnal freeze- thaw events. Diurnal frost processes were found to be azonal, and present at all three study locations. Evidence of landforms derived from diurnal frost processes were evident in each zone. Equifinality/convergence of form was present to a degree. The presence of patterned ground, which was not wholly derived from frost processes, suggests a measure of equifinality. Furthermore, openwork block deposits, of which not all are either blockstreams nor blockfields, are not necessarily the result of frost processes. The periglacial environment is poorly defined and methods to delineate this environment, as well as other climatic zones, should include additional parameters. Delineating zones on annual (and limited) monthly averages based on predominantly temperature, is not sufficient. While concepts of climatic geomorphology may be applied in a general sense, this framework is not suited to working at smaller scales. Specifically, periglacial environments should be delineated using ground moisture, as well as air temperature. Furthermore, vegetation and snow cover are important, as are soil textural properties.
- Full Text:
- Date Issued: 2018
On the development of ZnO nanorods on silicon substrate for light-emitting diode applications
- Djiokap, Stive Roussel Tankio
- Authors: Djiokap, Stive Roussel Tankio
- Date: 2018
- Subjects: Zinc oxide , Chemical reactions , Compound semiconductors
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/29973 , vital:30802
- Description: The interest in zinc oxide (ZnO), a promising material for blue/ultraviolet light emitting devices, arises from its large exciton binding energy (60 meV). The main challenge associated with this promising compound semiconductor, however, arises from the difficulty to achieve stable and/or reproducible p-type doping. Since silicon (Si) technology still dominates the semiconductor industry, the objective of this thesis is to probe into the possibility of using ZnO nanorods (NRs) on p-type silicon for opto-electronic devices. ZnO NRs have been grown on seeded Si, as well as on nickel oxide (NiO) and aluminum nitride (AlN) coated Si, using a two-step chemical bath deposition (CBD) process. Various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM), have been used to characterize the samples. The electrical characteristics of the heterojunction between the substrate and the ZnO nanostructures were evaluated by current-voltage (I-V) and capacitance-voltage (C-V) measurements. SEM and XRD studies have confirmed that, irrespective of the orientation of the Si substrate (Si (100) and Si (111)), the two-step CBD process yielded NRs that crystallised in the wurtzite structure and exhibited a hexagonal shape. Most of the rods developed perpendicularly to the surface of the substrate, with the orientation and distribution of the rods dictated by the seed layer density. Similarly, irrespective of the substrate, the luminescence of the ZnO nanostructures is dominated by near band edge (NBE) emission in the UV region (~ 3.29 eV) and deep level emission (DLE) in the visible region (2 eV to 2.6 eV). Annealing at moderate temperatures (~ 300 °C) increased the NBE emission and decreased the DLE. The removal of surface adsorbed impurities and enhanced defect passivation by hydrogen are responsible for these changes. The diode characteristics of the ZnO/Si heterojunction was studied by I-V and C-V measurements. Rectification was observed when the Si substrate had a relatively low acceptor density of ~1016 cm-3, while diodes produced on substrate with p ~1018 cm-3 were ohmic. From the C-V analysis the donor density in the ZnO was deduced to be ~1018 cm-3. In the case of rectifying junctions, thermionic emission did not dominate the charge transport. The carrier transport mechanism was therefore probed by the temperature dependent I-V xiii measurements (100 K to 295 K). Defect-assisted multistep tunneling was deduced to dominate in the n-ZnO/p-Si diodes at low forward bias. The band alignment between n-ZnO and p-Si predicts a much smaller barrier for electrons than for holes at the interface, which results in recombination on the Si side of the junction for a forward-biased diode. NiO intermediate layers (formed on Si by the thermal oxidation of Ni) were used to reduce electron injection from ZnO into Si. Scanning probe microscopy (SPM) and XRD analysis showed that while the grain size of the poly-crystalline NiO increased with NiO film thickness, the orientation and distribution of the subsequently grown ZnO nanorods were unaffected by the underlying NiO layer. Also, the photoluminescence response of the ZnO rods remained unchanged. I-V measurements did illustrate rectifying behaviour, with both the forward and reverse currents strongly decreased due to the resistive nature of the NiO. In another attempt at confining electrons to the ZnO side of the junction, AlN-coated Si (111) was used as a substrate for ZnO nanorods. CBD parameters that normally yield nanorods resulted in a plate-like architecture of the ZnO. By modifying the ZnO seed density on the AlN/Si substrate, the rod-like morphology could be recovered. Both the forward and reverse current decreased in these diodes. From studies aimed at identifying the transport mechanism it was concluded that trap-assisted tunnelling, resulting from a high density of defects in the seed layer, dominates in these devices. In conclusion, while no ZnO electroluminescence could be achieved from any of the devices, this study provides insight into the transport mechanisms in n-ZnO/barrier/p-Si heterostructures and highlights the importance of the heterointerface quality for light emitting devices.
- Full Text:
- Date Issued: 2018
- Authors: Djiokap, Stive Roussel Tankio
- Date: 2018
- Subjects: Zinc oxide , Chemical reactions , Compound semiconductors
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/29973 , vital:30802
- Description: The interest in zinc oxide (ZnO), a promising material for blue/ultraviolet light emitting devices, arises from its large exciton binding energy (60 meV). The main challenge associated with this promising compound semiconductor, however, arises from the difficulty to achieve stable and/or reproducible p-type doping. Since silicon (Si) technology still dominates the semiconductor industry, the objective of this thesis is to probe into the possibility of using ZnO nanorods (NRs) on p-type silicon for opto-electronic devices. ZnO NRs have been grown on seeded Si, as well as on nickel oxide (NiO) and aluminum nitride (AlN) coated Si, using a two-step chemical bath deposition (CBD) process. Various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM), have been used to characterize the samples. The electrical characteristics of the heterojunction between the substrate and the ZnO nanostructures were evaluated by current-voltage (I-V) and capacitance-voltage (C-V) measurements. SEM and XRD studies have confirmed that, irrespective of the orientation of the Si substrate (Si (100) and Si (111)), the two-step CBD process yielded NRs that crystallised in the wurtzite structure and exhibited a hexagonal shape. Most of the rods developed perpendicularly to the surface of the substrate, with the orientation and distribution of the rods dictated by the seed layer density. Similarly, irrespective of the substrate, the luminescence of the ZnO nanostructures is dominated by near band edge (NBE) emission in the UV region (~ 3.29 eV) and deep level emission (DLE) in the visible region (2 eV to 2.6 eV). Annealing at moderate temperatures (~ 300 °C) increased the NBE emission and decreased the DLE. The removal of surface adsorbed impurities and enhanced defect passivation by hydrogen are responsible for these changes. The diode characteristics of the ZnO/Si heterojunction was studied by I-V and C-V measurements. Rectification was observed when the Si substrate had a relatively low acceptor density of ~1016 cm-3, while diodes produced on substrate with p ~1018 cm-3 were ohmic. From the C-V analysis the donor density in the ZnO was deduced to be ~1018 cm-3. In the case of rectifying junctions, thermionic emission did not dominate the charge transport. The carrier transport mechanism was therefore probed by the temperature dependent I-V xiii measurements (100 K to 295 K). Defect-assisted multistep tunneling was deduced to dominate in the n-ZnO/p-Si diodes at low forward bias. The band alignment between n-ZnO and p-Si predicts a much smaller barrier for electrons than for holes at the interface, which results in recombination on the Si side of the junction for a forward-biased diode. NiO intermediate layers (formed on Si by the thermal oxidation of Ni) were used to reduce electron injection from ZnO into Si. Scanning probe microscopy (SPM) and XRD analysis showed that while the grain size of the poly-crystalline NiO increased with NiO film thickness, the orientation and distribution of the subsequently grown ZnO nanorods were unaffected by the underlying NiO layer. Also, the photoluminescence response of the ZnO rods remained unchanged. I-V measurements did illustrate rectifying behaviour, with both the forward and reverse currents strongly decreased due to the resistive nature of the NiO. In another attempt at confining electrons to the ZnO side of the junction, AlN-coated Si (111) was used as a substrate for ZnO nanorods. CBD parameters that normally yield nanorods resulted in a plate-like architecture of the ZnO. By modifying the ZnO seed density on the AlN/Si substrate, the rod-like morphology could be recovered. Both the forward and reverse current decreased in these diodes. From studies aimed at identifying the transport mechanism it was concluded that trap-assisted tunnelling, resulting from a high density of defects in the seed layer, dominates in these devices. In conclusion, while no ZnO electroluminescence could be achieved from any of the devices, this study provides insight into the transport mechanisms in n-ZnO/barrier/p-Si heterostructures and highlights the importance of the heterointerface quality for light emitting devices.
- Full Text:
- Date Issued: 2018
Parental influences on the next generation’s intention to join the family business
- Authors: Saunders, Shelley Beryl
- Date: 2018
- Subjects: Family-owned business enterprises -- Succession , Family-owned business enterprises -- Management Family corporations -- Management Success in business
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/35072 , vital:33612
- Description: Family businesses play an important role worldwide and in South Africa, in terms of their economic contribution and their ability to create jobs. However, the unwillingness of next generation family members (NGFMs) to join the family business seriously jeopardises its long-term survival. This is a matter of great concern for family business owners who in general have a strong desire to pass on the business to the next generation and to preserve the family’s legacy. Of the many factors relating to a person’s choice of career, parents are by far the most influential. Against this background, the purpose of this study was to gain a better understanding of the influence that parents have on the NGFM’s intentions to join the family business as well as the factors that moderate this influence. Establishing how parents influence an NGFM’s intention to join the family business makes an important theoretical contribution to family business, succession and entrepreneurial literatures, and holds both practical and theoretical relevance. The literature review provided an overview of the field of family business and discussed the nature of these businesses. Several frameworks, theories and perspectives relating to family businesses were elaborated on. The important role that family businesses play in the economies of countries and the unique challenges they face were highlighted. One of the most important challenges facing family businesses is that of transgenerational succession and the willingness of the next generation to make the family business their career choice. Several behaviour and career choice theories were discussed, particularly in relation to the South African context, and a summary of all the factors influencing career choice in terms of these theories was presented. Several parental influences on career choice were identified and examined in detail, namely Parent–child relationship, Parents’ job characteristics, Parental financial security, Parental job satisfaction, Parental identification, Parental expectations, Parental support and Parental style. Additionally, the influence of each parental influences on NGFMs, in a family business context, was highlighted. Based on anecdotal and empirical support, these parental influences were hypothesised as influencing the dependent variable in this study, namely Intention to join the family business. Based on the social cognitive career theory, Self-efficacy and Outcome expectations were hypothesised as moderating the aforementioned relationships. This study adopted a positivist research paradigm and a quantitative methodological approach that was deductive in nature. The methodology adopted to collect primary data was a cross-sectional analytical survey. A structured questionnaire was distributed to respondents who were identified by means of judgemental sampling and 453 completed questionnaires were subjected to statistical analysis. The validity of the scales measuring the dependent, moderating and independent variables was assessed by means of factor analysis and the reliability thereof by calculating Cronbach’s alpha coefficients. Both descriptive and inferential statistics were calculated. Multiple regression analysis (MRA) was used to assess the hypothesised relationships. The findings show that only one third of the respondents agreed that they had Intentions to join the family business. Furthermore, the results of the MRA reported significant and positive relationships between the independent variables Parental expectations, Perceived parental outcomes, and Parental identification, and the dependent variable Intention to join the family business. The results of the moderated regression analysis revealed that Self-efficacy and Outcome expectations do not moderate the relationships between all the parental influences investigated and Intention to join the family business as hypothesised. However, a significant positive relationship at the ten per cent confidence level was reported between the interaction effect, Self-efficacy x Perceived parental outcomes, and Intention to join the family business. A significant positive relationship at the five per cent confidence level was also reported between the interaction effect Outcome expectations x Parental identification, and Intention to join the family business. Based on the findings of this study, numerous recommendations were made. This study makes a contribution to both theory and practice. In terms of theory, the results have highlighted the applicability of both the theory of planned behaviour and the social cognitive career theory in explaining an NGFM’s Intention to join the family business. In addition, the applicability of these theories in the family business context has been confirmed. This study also contributes to the family business literature in that it provides new insights into how parents influence one of family businesses’ biggest challenges, namely their children not wanting to take over the family business. In terms of practice, the findings show that that several of the parental influences investigated do indeed increase the intention of NGFMs to join the family business. It is anticipated that these findings will encourage parents who own family businesses to take note of how they influence their children’s decision whether to join them in the family business, and ultimately to contribute to its possible long-term survival and success.
- Full Text:
- Date Issued: 2018
- Authors: Saunders, Shelley Beryl
- Date: 2018
- Subjects: Family-owned business enterprises -- Succession , Family-owned business enterprises -- Management Family corporations -- Management Success in business
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/35072 , vital:33612
- Description: Family businesses play an important role worldwide and in South Africa, in terms of their economic contribution and their ability to create jobs. However, the unwillingness of next generation family members (NGFMs) to join the family business seriously jeopardises its long-term survival. This is a matter of great concern for family business owners who in general have a strong desire to pass on the business to the next generation and to preserve the family’s legacy. Of the many factors relating to a person’s choice of career, parents are by far the most influential. Against this background, the purpose of this study was to gain a better understanding of the influence that parents have on the NGFM’s intentions to join the family business as well as the factors that moderate this influence. Establishing how parents influence an NGFM’s intention to join the family business makes an important theoretical contribution to family business, succession and entrepreneurial literatures, and holds both practical and theoretical relevance. The literature review provided an overview of the field of family business and discussed the nature of these businesses. Several frameworks, theories and perspectives relating to family businesses were elaborated on. The important role that family businesses play in the economies of countries and the unique challenges they face were highlighted. One of the most important challenges facing family businesses is that of transgenerational succession and the willingness of the next generation to make the family business their career choice. Several behaviour and career choice theories were discussed, particularly in relation to the South African context, and a summary of all the factors influencing career choice in terms of these theories was presented. Several parental influences on career choice were identified and examined in detail, namely Parent–child relationship, Parents’ job characteristics, Parental financial security, Parental job satisfaction, Parental identification, Parental expectations, Parental support and Parental style. Additionally, the influence of each parental influences on NGFMs, in a family business context, was highlighted. Based on anecdotal and empirical support, these parental influences were hypothesised as influencing the dependent variable in this study, namely Intention to join the family business. Based on the social cognitive career theory, Self-efficacy and Outcome expectations were hypothesised as moderating the aforementioned relationships. This study adopted a positivist research paradigm and a quantitative methodological approach that was deductive in nature. The methodology adopted to collect primary data was a cross-sectional analytical survey. A structured questionnaire was distributed to respondents who were identified by means of judgemental sampling and 453 completed questionnaires were subjected to statistical analysis. The validity of the scales measuring the dependent, moderating and independent variables was assessed by means of factor analysis and the reliability thereof by calculating Cronbach’s alpha coefficients. Both descriptive and inferential statistics were calculated. Multiple regression analysis (MRA) was used to assess the hypothesised relationships. The findings show that only one third of the respondents agreed that they had Intentions to join the family business. Furthermore, the results of the MRA reported significant and positive relationships between the independent variables Parental expectations, Perceived parental outcomes, and Parental identification, and the dependent variable Intention to join the family business. The results of the moderated regression analysis revealed that Self-efficacy and Outcome expectations do not moderate the relationships between all the parental influences investigated and Intention to join the family business as hypothesised. However, a significant positive relationship at the ten per cent confidence level was reported between the interaction effect, Self-efficacy x Perceived parental outcomes, and Intention to join the family business. A significant positive relationship at the five per cent confidence level was also reported between the interaction effect Outcome expectations x Parental identification, and Intention to join the family business. Based on the findings of this study, numerous recommendations were made. This study makes a contribution to both theory and practice. In terms of theory, the results have highlighted the applicability of both the theory of planned behaviour and the social cognitive career theory in explaining an NGFM’s Intention to join the family business. In addition, the applicability of these theories in the family business context has been confirmed. This study also contributes to the family business literature in that it provides new insights into how parents influence one of family businesses’ biggest challenges, namely their children not wanting to take over the family business. In terms of practice, the findings show that that several of the parental influences investigated do indeed increase the intention of NGFMs to join the family business. It is anticipated that these findings will encourage parents who own family businesses to take note of how they influence their children’s decision whether to join them in the family business, and ultimately to contribute to its possible long-term survival and success.
- Full Text:
- Date Issued: 2018
Parental involvement and grade 8 learners' academic achievement in mathematics : a study of selected schools in East London, South Africa
- Authors: Eesuola, Omobola Foluke
- Date: 2018
- Subjects: Education -- Parent participation -- South Africa
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/10497 , vital:35497
- Description: This investigation springs from the realization that academic achievement is influenced by different environmental factors. The influence of parental involvement on learners’ academic achievement has been recognized globally by experts in the education industry. As integral as parental involvement is, education industry is yet to come to terms on the best type of parental involvement needed for the teaching and learning of Mathematics in high schools especially at the transition phase. The aim of this study was to establish the relationship between parental involvement and grade 8 learners’ academic achievement in Mathematics. Quantitative research method was used for data collection. The data was collected with the use of parental involvement questionnaire for learners (PIQL) and learners Mathematics academic achievement scores. The research was conducted in six schools (public and private) within the East London Education District. The total sample size was 460 Grade 8 learners who were randomly selected across the board. The outcomes of the investigation revealed that parental involvement enhances the academic achievement of grade 8 learners irrespective of a definition of it or the measure of achievement. Furthermore, the results of this findings indicate that good parenting styles, parental support and parental educational background (r = 0.54; P < 0.05), (r =0.20; P< 0.05), (r = 0.68; P < 0.05) respectively are prerequisite for learners’ academic achievement in mathematics, showing that the variables are significantly related to learners academic achievement in mathematics; while parental involvement in the area of communication and family structure were very weak (r = 0.05; P > 0.05), (R=0.09; R2=.005; P < 0.05). This study therefore, recommended that parental involvement should be beefed up especially in areas of communication and family structure, by both the parents and teachers in order to enhance learners’ academic achievement in Mathematics.
- Full Text:
- Date Issued: 2018
- Authors: Eesuola, Omobola Foluke
- Date: 2018
- Subjects: Education -- Parent participation -- South Africa
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/10497 , vital:35497
- Description: This investigation springs from the realization that academic achievement is influenced by different environmental factors. The influence of parental involvement on learners’ academic achievement has been recognized globally by experts in the education industry. As integral as parental involvement is, education industry is yet to come to terms on the best type of parental involvement needed for the teaching and learning of Mathematics in high schools especially at the transition phase. The aim of this study was to establish the relationship between parental involvement and grade 8 learners’ academic achievement in Mathematics. Quantitative research method was used for data collection. The data was collected with the use of parental involvement questionnaire for learners (PIQL) and learners Mathematics academic achievement scores. The research was conducted in six schools (public and private) within the East London Education District. The total sample size was 460 Grade 8 learners who were randomly selected across the board. The outcomes of the investigation revealed that parental involvement enhances the academic achievement of grade 8 learners irrespective of a definition of it or the measure of achievement. Furthermore, the results of this findings indicate that good parenting styles, parental support and parental educational background (r = 0.54; P < 0.05), (r =0.20; P< 0.05), (r = 0.68; P < 0.05) respectively are prerequisite for learners’ academic achievement in mathematics, showing that the variables are significantly related to learners academic achievement in mathematics; while parental involvement in the area of communication and family structure were very weak (r = 0.05; P > 0.05), (R=0.09; R2=.005; P < 0.05). This study therefore, recommended that parental involvement should be beefed up especially in areas of communication and family structure, by both the parents and teachers in order to enhance learners’ academic achievement in Mathematics.
- Full Text:
- Date Issued: 2018
Parents' experiences with involvement in the education development of children under six years in the Bubi District of Zimbabwe
- Authors: Mhlanga, Sibonginkosi
- Date: 2018
- Subjects: Education -- Parent participation -- Zimbabwe Education, Elementary -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9467 , vital:34354
- Description: This study on parental involvement in Early Childhood Development in the Bubi district of Zimbabwe investigates parents’ experiences with involvement in the education development of children under six years. Early Childhood Development in Zimbabwe is a community based programme, hence the interest on parents in their involvement in the education and development. To investigate this phenomenon a thorough background of the Bronfenbrenner’s ecological systems theory was employed. The theory is based on the principles of interconnectedness within settings and the linkages between settings that affect individual development. The study focused on the immediate, being the microsystems. The interpretive paradigm and the qualitative approach were employed to explore the parents’ experiences with involvement in the education development of children under six years. Purposive sampling was used to select a small sample of two Heads of schools, four Early Childhood Development teachers and sixteen parents; these were from two schools in the Bubi district of Matabeleland, North Province of Zimbabwe. Obtained results reveal that all the stakeholders involved in the study seem to have limited knowledge of parental involvement. It also emerged that the involvement in the district is biased towards the physical needs of the school only. The results also revealed that there are so many factors that contribute to the non-involvement of parents in their children’s education and development such as poverty, lack of knowledge, culture and attitude, just to mention a few. In view of the findings the study recommends that the Government should provide statutory instruments that clearly state the role of the parents, especially because of the fact that, currently, the programme in the country is community based. The colleges should also empower student teachers during their training on parental involvement.
- Full Text:
- Date Issued: 2018
- Authors: Mhlanga, Sibonginkosi
- Date: 2018
- Subjects: Education -- Parent participation -- Zimbabwe Education, Elementary -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9467 , vital:34354
- Description: This study on parental involvement in Early Childhood Development in the Bubi district of Zimbabwe investigates parents’ experiences with involvement in the education development of children under six years. Early Childhood Development in Zimbabwe is a community based programme, hence the interest on parents in their involvement in the education and development. To investigate this phenomenon a thorough background of the Bronfenbrenner’s ecological systems theory was employed. The theory is based on the principles of interconnectedness within settings and the linkages between settings that affect individual development. The study focused on the immediate, being the microsystems. The interpretive paradigm and the qualitative approach were employed to explore the parents’ experiences with involvement in the education development of children under six years. Purposive sampling was used to select a small sample of two Heads of schools, four Early Childhood Development teachers and sixteen parents; these were from two schools in the Bubi district of Matabeleland, North Province of Zimbabwe. Obtained results reveal that all the stakeholders involved in the study seem to have limited knowledge of parental involvement. It also emerged that the involvement in the district is biased towards the physical needs of the school only. The results also revealed that there are so many factors that contribute to the non-involvement of parents in their children’s education and development such as poverty, lack of knowledge, culture and attitude, just to mention a few. In view of the findings the study recommends that the Government should provide statutory instruments that clearly state the role of the parents, especially because of the fact that, currently, the programme in the country is community based. The colleges should also empower student teachers during their training on parental involvement.
- Full Text:
- Date Issued: 2018