Integration of small-scale mohair farmers into the commercial agricultural economy in Lesotho: a new institutional economics approach
- Authors: Rantlo, Montoeli Ashby
- Date: 2018
- Subjects: Farms, Small Lesotho , Mohair Lesotho , Institutional economics , Transaction costs , Informal sector (Economics)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62275 , vital:28149
- Description: Agriculture continues to be a strategic sector in the development of most low-income countries like Lesotho where small-scale farming is the dominant livelihood activity that provides income and employment to the people. Smallholder farmers' integration into the commercial agricultural markets is a crucial element for economic development and has become a part of development strategies for developing countries and the objectives of international development institutions. The integration of the smallholders into these markets is dependent upon a number of factors including formal and informal institutions. Factors like population growth and demographic changes, technological change and introduction of new commodities, development of infrastructure and market institutions, development of the nonfarm sector and broader economy, rising labour opportunity costs, and macroeconomic, trade and sectoral policies affecting prices and other driving forces determine market participation. In addition, development of input and output markets, institutions like property rights and land tenure, market regulations, cultural and social factors affecting consumption preferences, production and market opportunities and constraints, agro-climatic conditions, and production and market related risks are other factors that affect the commercialisation process. On the other hand, factors like smallholder resource endowments including land and other natural capital, labour, physical capital, and human capital among others are household specific and considered internal determinants of market participation. Nevertheless, the decision to participate in agricultural markets lies with the individual farming household. Under the New Institutional Economics (NIE), this decision is influenced by institutional factors such as risk and preferences, factors which affect household production and the level of costs associated with market transactions. These market transactions are commonly referred to as transaction costs. The study focused on investigating the institutions that limit the integration of small-scale mohair farmers into the commercial agricultural economy in Lesotho. The documentation and evaluation of the institutional structure of the mohair industry is performed whereby the institutional factors influencing participation of small-scale mohair farmers in formal, informal and illegal markets in Lesotho and factors contributing to transaction costs associated with the integration of small-scale farmers into the commercial mohair sector are investigated. Therefore, the investigation will help to address the institutional problems hindering the development of an effective marketing structure for the commercialisation of small-scale mohair producers in Lesotho. The results of the study show that the small-scale mohair farmers that use the formal markets are integrated into the commercial agricultural economy and these farmers' integration into the mainstream economy is influenced by access to government support in the form of shearing sheds, transport subsidies and advisory services. They also have access to market information, marketing infrastructure, knowledge of grades and standards and secure property rights. Other factors that helped their integration into the commercial economy is their contractual agreements with mohair buyers, path dependent based decision making as well as the collective approach to mohair farming. The small-scale mohair farmers using the informal markets do not receive the advantages received by the famers in the formal markets. These small-scale mohair farmers are not integrated into the commercial markets and their only option is the informal markets and their participation in these markets is enhanced by their marketing arrangements with the informal traders, culture influenced decisions, social capital and prompt payments. Despite integration into the commercial agricultural economy, small-scale farmers that use formal markets face the challenges of power imbalances, mistrust and conflicts which may affect this integration into the commercial markets if left unchecked. The study concludes that in the face of institutional challenges, the small-scale mohair farmers using the formal markets are integrated into the commercial agricultural economy and there is potential for improvement of their integration as well as the integration of the small-scale mohair farmers that use the informal markets if institutional challenges are addressed.
- Full Text:
- Date Issued: 2018
- Authors: Rantlo, Montoeli Ashby
- Date: 2018
- Subjects: Farms, Small Lesotho , Mohair Lesotho , Institutional economics , Transaction costs , Informal sector (Economics)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62275 , vital:28149
- Description: Agriculture continues to be a strategic sector in the development of most low-income countries like Lesotho where small-scale farming is the dominant livelihood activity that provides income and employment to the people. Smallholder farmers' integration into the commercial agricultural markets is a crucial element for economic development and has become a part of development strategies for developing countries and the objectives of international development institutions. The integration of the smallholders into these markets is dependent upon a number of factors including formal and informal institutions. Factors like population growth and demographic changes, technological change and introduction of new commodities, development of infrastructure and market institutions, development of the nonfarm sector and broader economy, rising labour opportunity costs, and macroeconomic, trade and sectoral policies affecting prices and other driving forces determine market participation. In addition, development of input and output markets, institutions like property rights and land tenure, market regulations, cultural and social factors affecting consumption preferences, production and market opportunities and constraints, agro-climatic conditions, and production and market related risks are other factors that affect the commercialisation process. On the other hand, factors like smallholder resource endowments including land and other natural capital, labour, physical capital, and human capital among others are household specific and considered internal determinants of market participation. Nevertheless, the decision to participate in agricultural markets lies with the individual farming household. Under the New Institutional Economics (NIE), this decision is influenced by institutional factors such as risk and preferences, factors which affect household production and the level of costs associated with market transactions. These market transactions are commonly referred to as transaction costs. The study focused on investigating the institutions that limit the integration of small-scale mohair farmers into the commercial agricultural economy in Lesotho. The documentation and evaluation of the institutional structure of the mohair industry is performed whereby the institutional factors influencing participation of small-scale mohair farmers in formal, informal and illegal markets in Lesotho and factors contributing to transaction costs associated with the integration of small-scale farmers into the commercial mohair sector are investigated. Therefore, the investigation will help to address the institutional problems hindering the development of an effective marketing structure for the commercialisation of small-scale mohair producers in Lesotho. The results of the study show that the small-scale mohair farmers that use the formal markets are integrated into the commercial agricultural economy and these farmers' integration into the mainstream economy is influenced by access to government support in the form of shearing sheds, transport subsidies and advisory services. They also have access to market information, marketing infrastructure, knowledge of grades and standards and secure property rights. Other factors that helped their integration into the commercial economy is their contractual agreements with mohair buyers, path dependent based decision making as well as the collective approach to mohair farming. The small-scale mohair farmers using the informal markets do not receive the advantages received by the famers in the formal markets. These small-scale mohair farmers are not integrated into the commercial markets and their only option is the informal markets and their participation in these markets is enhanced by their marketing arrangements with the informal traders, culture influenced decisions, social capital and prompt payments. Despite integration into the commercial agricultural economy, small-scale farmers that use formal markets face the challenges of power imbalances, mistrust and conflicts which may affect this integration into the commercial markets if left unchecked. The study concludes that in the face of institutional challenges, the small-scale mohair farmers using the formal markets are integrated into the commercial agricultural economy and there is potential for improvement of their integration as well as the integration of the small-scale mohair farmers that use the informal markets if institutional challenges are addressed.
- Full Text:
- Date Issued: 2018
Integration of the new development bank into the international financial architecture
- Chitenderu, Tafadzwa Thelmah
- Authors: Chitenderu, Tafadzwa Thelmah
- Date: 2018
- Subjects: World Bank , International Monetary Fund -- Developing countries Economic development -- International cooperation Financial institutions, International
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/23924 , vital:30645
- Description: The study looked at the integration of the BRICS New Development Bank into the international financial architecture. In doing so, it made use of an econometric evaluation of the impact of the loans received from the current dominant financial institutions, namely International Monetary Fund (IMF) and the World Bank, on economic growth of ten self-selected African countries. Given the challenges and the failures of the Western dominated funding to African countries, it is important to ensure that the funding approach of the New Development Bank does not resemble that of the current international finance system. Using panel data and quantile regression econometric models on annual data from ten self-selected African countries that are recipients of World Bank and IMF loans from 1994 to 2014, this thesis presents a framework for the integration of the BRICS’ New Development Bank into the global financial architecture. The results obtained shows a negative and statistically significant impact of World Bank loans on Gross Domestic Product of the country under analysis and a positive statistically insignificant impact of IMF loans. Given the existing global financial institutions and the wealth of expertise at their disposal, this thesis concludes that the existing global financial structure cannot be done away with completely but the New Development Bank should rather perform a complementary role in the global finance space. Accordingly, the New Development Bank should champion a ‘post ideological rhetoric’ in the global financial architecture.
- Full Text:
- Date Issued: 2018
- Authors: Chitenderu, Tafadzwa Thelmah
- Date: 2018
- Subjects: World Bank , International Monetary Fund -- Developing countries Economic development -- International cooperation Financial institutions, International
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/23924 , vital:30645
- Description: The study looked at the integration of the BRICS New Development Bank into the international financial architecture. In doing so, it made use of an econometric evaluation of the impact of the loans received from the current dominant financial institutions, namely International Monetary Fund (IMF) and the World Bank, on economic growth of ten self-selected African countries. Given the challenges and the failures of the Western dominated funding to African countries, it is important to ensure that the funding approach of the New Development Bank does not resemble that of the current international finance system. Using panel data and quantile regression econometric models on annual data from ten self-selected African countries that are recipients of World Bank and IMF loans from 1994 to 2014, this thesis presents a framework for the integration of the BRICS’ New Development Bank into the global financial architecture. The results obtained shows a negative and statistically significant impact of World Bank loans on Gross Domestic Product of the country under analysis and a positive statistically insignificant impact of IMF loans. Given the existing global financial institutions and the wealth of expertise at their disposal, this thesis concludes that the existing global financial structure cannot be done away with completely but the New Development Bank should rather perform a complementary role in the global finance space. Accordingly, the New Development Bank should champion a ‘post ideological rhetoric’ in the global financial architecture.
- Full Text:
- Date Issued: 2018
Interaction of catechol O-methyltransferase with gold and silver nanoparticles
- Authors: Usman, Aminu
- Date: 2018
- Subjects: Parkinson's disease , Methyltransferases , Catechol , Nanoparticles
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/61818 , vital:28063 , DOI https://doi.org/10.21504/10962/61818
- Description: Catechol O-methyltransferase (S-adenosyl-Z-methionine: catechol O-methyltransferase; COMT; EC 2.1.1.6) is a ubiquitous enzyme that catalyses the transfer of a methyl group from the cofactor, S-adenosyl-Z-methionine (SAM) to a hydroxyl group of endogenous and exogenous catechol-containing moieties. The physiological role of this enzyme is the methylation and thereby inactivation of the catechol-containing bio-active and bio-toxic compounds, including catechol-neurotransmitters, catechol-estrogens and catechol-containing drugs. Activity of this enzyme is implicated in the treatment of Parkinson’s disease and is associated with other diseases including breast cancer and an array neuropsychological disorders, such as schizophrenia. This thesis explores the use of gold and silver nanoparticles (NPs) (AuNPs and AgNPs) to inhibit the catalytic activity of mammalian COMT. Because of its accessibility and availability, we initially investigated bovine soluble COMT (BSCOMT) from liver tissue. Bioinformatic analyses and structural modeling revealed high (>90%) sequence similarity between BSCOMT and human soluble COMT (HSCOMT). BSCOMT was partially purified to 7.78 fold, 1.65% yield and had a specific activity of 0.052 U/mg. It had pH and temperature optima of 8.5 and 40oC, respectively. The Km, Vmax, Kcat and Kcat/Km towards esculetin methylation were respectively 1.475±0.130 pM, 0.0353±0.001 pmol/ml/min, 1.748 x 10-2±5.0x10-4 min-1 and 1.18x10-2 M-1. min-1. HSCOMT was expressed in Escherichia coli BL21(DE3) which showed optimal activity for esculetin methylation at pH and temperature of 7.0 and 30°C, respectively. It was purified to 5.62 fold, 22.6% yield with a specific activity of 3.85 U/mg. HSCOMT kinetic plots, upon incubation of the reaction mixture at 30°C for 5 min before addition of SAM was hyperbolic with Km, Vmax, Kcat and Kcat/Km values of 1.79 pM, 0.412 pmol/ml/min, 2.08 min-1 and 1.165 M-1. min-1, respectively. AuNPs and AgNPs showed a concentration dependent inhibition of HSCOMT activity upon increasing the 5 min incubation time to 1 h. Interestingly, HSCOMT kinetics, with 1 h incubation at 30°C, showed a sigmoidal curve, as well as increased activity. Incubation of the reaction mixture in the presence of 60 pM AuNPs and/or AgNPs for 1 hreversed the observed sigmoidal to a hyperbolic curve, with kinetic parameters comparable to those of 5 min incubation. SDS-PAGE analyses of HSCOMT after the kinetic experiments showed the enzyme incubated for 5 min as a monomer, while that which was incubated for 1 h migrated substantially as dimer. However, the HSCOMT incubated for 1 h in the presence of 60 pM AuNPs and/or AgNPs migrated as a monomer. This indicated that the extension of the incubation period allowed the dimerization of HSCOMT, which exhibited sigmoidal kinetics and higher activity. The presence of NPs impeded the HSCOMT dimerization which decreased the activity. Varying the concentration of SAM suggested that SAM had an allosteric modulatory effect on HSCOMT. Absorption spectroscopy indicated adsorption of HSCOMT on the gold and silver NP surfaces and the formation of NPs-HSCOMT corona. Fluorescence spectroscopy showed that the interaction of HSCOMT with both gold and silver NPs was governed by a static quenching mechanism, implying the formation of a non-fluorescent fluorophore-NP complex at the ground state. Further fluorometric analyses indicated that both gold and silver NPs had contact with Trp143; that the interactions were spontaneous and were driven by electrostatic interactions. Fourier transform infrared spectroscopic studies showed the adsorption of HSCOMT of the NPs surfaces to cause relaxation of the enzyme’s B-sheet structures. Molecular docking studies indicated involvement of largely hydrophilic amino acids, with the interacting distances of less than 3.5A. These findings signify the potential of nanotechnology in the control of COMT catalytic activity for the management of the COMT-related disorders. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
- Authors: Usman, Aminu
- Date: 2018
- Subjects: Parkinson's disease , Methyltransferases , Catechol , Nanoparticles
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/61818 , vital:28063 , DOI https://doi.org/10.21504/10962/61818
- Description: Catechol O-methyltransferase (S-adenosyl-Z-methionine: catechol O-methyltransferase; COMT; EC 2.1.1.6) is a ubiquitous enzyme that catalyses the transfer of a methyl group from the cofactor, S-adenosyl-Z-methionine (SAM) to a hydroxyl group of endogenous and exogenous catechol-containing moieties. The physiological role of this enzyme is the methylation and thereby inactivation of the catechol-containing bio-active and bio-toxic compounds, including catechol-neurotransmitters, catechol-estrogens and catechol-containing drugs. Activity of this enzyme is implicated in the treatment of Parkinson’s disease and is associated with other diseases including breast cancer and an array neuropsychological disorders, such as schizophrenia. This thesis explores the use of gold and silver nanoparticles (NPs) (AuNPs and AgNPs) to inhibit the catalytic activity of mammalian COMT. Because of its accessibility and availability, we initially investigated bovine soluble COMT (BSCOMT) from liver tissue. Bioinformatic analyses and structural modeling revealed high (>90%) sequence similarity between BSCOMT and human soluble COMT (HSCOMT). BSCOMT was partially purified to 7.78 fold, 1.65% yield and had a specific activity of 0.052 U/mg. It had pH and temperature optima of 8.5 and 40oC, respectively. The Km, Vmax, Kcat and Kcat/Km towards esculetin methylation were respectively 1.475±0.130 pM, 0.0353±0.001 pmol/ml/min, 1.748 x 10-2±5.0x10-4 min-1 and 1.18x10-2 M-1. min-1. HSCOMT was expressed in Escherichia coli BL21(DE3) which showed optimal activity for esculetin methylation at pH and temperature of 7.0 and 30°C, respectively. It was purified to 5.62 fold, 22.6% yield with a specific activity of 3.85 U/mg. HSCOMT kinetic plots, upon incubation of the reaction mixture at 30°C for 5 min before addition of SAM was hyperbolic with Km, Vmax, Kcat and Kcat/Km values of 1.79 pM, 0.412 pmol/ml/min, 2.08 min-1 and 1.165 M-1. min-1, respectively. AuNPs and AgNPs showed a concentration dependent inhibition of HSCOMT activity upon increasing the 5 min incubation time to 1 h. Interestingly, HSCOMT kinetics, with 1 h incubation at 30°C, showed a sigmoidal curve, as well as increased activity. Incubation of the reaction mixture in the presence of 60 pM AuNPs and/or AgNPs for 1 hreversed the observed sigmoidal to a hyperbolic curve, with kinetic parameters comparable to those of 5 min incubation. SDS-PAGE analyses of HSCOMT after the kinetic experiments showed the enzyme incubated for 5 min as a monomer, while that which was incubated for 1 h migrated substantially as dimer. However, the HSCOMT incubated for 1 h in the presence of 60 pM AuNPs and/or AgNPs migrated as a monomer. This indicated that the extension of the incubation period allowed the dimerization of HSCOMT, which exhibited sigmoidal kinetics and higher activity. The presence of NPs impeded the HSCOMT dimerization which decreased the activity. Varying the concentration of SAM suggested that SAM had an allosteric modulatory effect on HSCOMT. Absorption spectroscopy indicated adsorption of HSCOMT on the gold and silver NP surfaces and the formation of NPs-HSCOMT corona. Fluorescence spectroscopy showed that the interaction of HSCOMT with both gold and silver NPs was governed by a static quenching mechanism, implying the formation of a non-fluorescent fluorophore-NP complex at the ground state. Further fluorometric analyses indicated that both gold and silver NPs had contact with Trp143; that the interactions were spontaneous and were driven by electrostatic interactions. Fourier transform infrared spectroscopic studies showed the adsorption of HSCOMT of the NPs surfaces to cause relaxation of the enzyme’s B-sheet structures. Molecular docking studies indicated involvement of largely hydrophilic amino acids, with the interacting distances of less than 3.5A. These findings signify the potential of nanotechnology in the control of COMT catalytic activity for the management of the COMT-related disorders. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
Interactions between three biological control agents of water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae) in South Africa
- Authors: Petela, Nomvume
- Date: 2018
- Subjects: Water hyacinth -- South Africa , Water hyacinth -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Curculionidae , Delphacidae , Miridae , Neochetina eichhorniae Warner , Megamelus scutellaris Berg , Eccritotarsus eichhorniae Henry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60676 , vital:27814
- Description: Water hyacinth, Eichhomia crassipes (Mart.) Solms (Pontederiaceae) is a free-floating perennial weed that is regarded as the worst aquatic weed in the world because of its negative impacts on aquatic ecosystems. It is native to the Amazon Basin of South America, but since the late 1800s has spread throughout the world. The first record of the weed in South Africa was noted in 1908 on the Cape Flats and in KwaZulu-Natal, but it is now dispersed throughout the country. Mechanical and chemical control methods have been used against the weed, but biological control is considered the most cost-effective, sustainable and environmentally friendly intervention. Currently, nine biological control agents have been released against water hyacinth in South Africa, and Neochetina eichhorniae Warner (Coleoptera: Curculionidae) is used most widely to control it. However, in some sites, water hyacinth mats have still not been brought under control because of eutrophic waters and cool temperatures. It was therefore necessary to release new biological control agents to complement the impact of N. eichhorniae. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released in 2013, but little is known about how it interacts with other agents already present in South Africa. It is likely to compete with the established biological control agent, Eccritotarsus eichhorniae Henry (Heteroptera: Miridae), because they are both sap suckers. On the other hand, N. eichhorniae is the most widespread and thus the most important biological control agent for water hyacinth. The aim of this study, then, was to determine the interactions between the two sap-sucking agents in South Africa that presumably occupy similar niches on the plant, and the interaction between M. scutellerais and N. eichhorniae, the most widely distributed and abundant agent in South Africa. Three experiments were conducted at the Waainek Research Facility at Rhodes University, Grahamstown, Eastern Cape, South Africa. Plants were grown for two weeks and insect species were inoculated singly or in combination. Water hyacinth, plant growth parameters and insect parameters were measured every 14 days for a period of 12 weeks. The results of the study showed that feeding by either E. eichhorniae or M. scutellaris had no effect on the feeding of the other agent. Both agents reduced all the measured plant growth parameters equally, either singly or in combination (i.e. E. eichhorniae or M. scutellaris alone or together). The interaction between the two agents appears neutral and agents are likely to complement each other in the field. Prior feeding by E. eichhorniae or M. scutellaris on water hyacinth did not affect the subsequent feeding by either agent. Megamelus scutellaris prefers healthy fresh water hyacinth plants. In addition, planthoppers performed best in combination with the weevil, especially on plants with new weevil feeding scars. The results of the study showed that M. scutellaris is compatible with other biological control agents of water hyacinth that are already established in South Africa. Therefore, the introduction of M. scutellaris may enhance the biological control of water hyacinth in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Petela, Nomvume
- Date: 2018
- Subjects: Water hyacinth -- South Africa , Water hyacinth -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Curculionidae , Delphacidae , Miridae , Neochetina eichhorniae Warner , Megamelus scutellaris Berg , Eccritotarsus eichhorniae Henry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60676 , vital:27814
- Description: Water hyacinth, Eichhomia crassipes (Mart.) Solms (Pontederiaceae) is a free-floating perennial weed that is regarded as the worst aquatic weed in the world because of its negative impacts on aquatic ecosystems. It is native to the Amazon Basin of South America, but since the late 1800s has spread throughout the world. The first record of the weed in South Africa was noted in 1908 on the Cape Flats and in KwaZulu-Natal, but it is now dispersed throughout the country. Mechanical and chemical control methods have been used against the weed, but biological control is considered the most cost-effective, sustainable and environmentally friendly intervention. Currently, nine biological control agents have been released against water hyacinth in South Africa, and Neochetina eichhorniae Warner (Coleoptera: Curculionidae) is used most widely to control it. However, in some sites, water hyacinth mats have still not been brought under control because of eutrophic waters and cool temperatures. It was therefore necessary to release new biological control agents to complement the impact of N. eichhorniae. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released in 2013, but little is known about how it interacts with other agents already present in South Africa. It is likely to compete with the established biological control agent, Eccritotarsus eichhorniae Henry (Heteroptera: Miridae), because they are both sap suckers. On the other hand, N. eichhorniae is the most widespread and thus the most important biological control agent for water hyacinth. The aim of this study, then, was to determine the interactions between the two sap-sucking agents in South Africa that presumably occupy similar niches on the plant, and the interaction between M. scutellerais and N. eichhorniae, the most widely distributed and abundant agent in South Africa. Three experiments were conducted at the Waainek Research Facility at Rhodes University, Grahamstown, Eastern Cape, South Africa. Plants were grown for two weeks and insect species were inoculated singly or in combination. Water hyacinth, plant growth parameters and insect parameters were measured every 14 days for a period of 12 weeks. The results of the study showed that feeding by either E. eichhorniae or M. scutellaris had no effect on the feeding of the other agent. Both agents reduced all the measured plant growth parameters equally, either singly or in combination (i.e. E. eichhorniae or M. scutellaris alone or together). The interaction between the two agents appears neutral and agents are likely to complement each other in the field. Prior feeding by E. eichhorniae or M. scutellaris on water hyacinth did not affect the subsequent feeding by either agent. Megamelus scutellaris prefers healthy fresh water hyacinth plants. In addition, planthoppers performed best in combination with the weevil, especially on plants with new weevil feeding scars. The results of the study showed that M. scutellaris is compatible with other biological control agents of water hyacinth that are already established in South Africa. Therefore, the introduction of M. scutellaris may enhance the biological control of water hyacinth in South Africa.
- Full Text:
- Date Issued: 2018
Interest rate liberalisation and economic growth in SADC countries
- Authors: Moyo, Clement Zibusiso
- Date: 2018
- Subjects: Southern African Development Community , Economic development -- Africa, Southern Developing countries -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/22791 , vital:30087
- Description: The pioneers of financial liberalisation, McKinnon (1973) and Shaw (1973) argue that inter-est rates determined by market forces have a positive effect on economic growth rates. Inter-est rates that are kept at low levels through the intervention of a central bank discourage sav-ings and capital accumulation, and distort the allocation of resources. Interest rate liberalisa-tion results in higher real interest rates which could have a positive effect on savings, invest-ments and economic growth (Ang & McKibbin 2007). Interest rate liberalisation also reduces capital flight and encourages capital inflows by increasing return for investors which supple-ments domestic investments. Shaw (1973) argued that interest rate liberalisation promotes financial development by encouraging savings and increasing the availability of funds for lending purposes. The study provides an empirical analysis of the channels through which interest rate liberalisation impacts on economic growth in SADC countries for the period 1990 to 2015. The study is motivated by the concerns on the impact of interest rate liberalisation on eco-nomic growth in the period after the 2008-’09 global financial crisis as well as concerns that interest rate liberalisation increases the likelihood of financial crises. Higher interest rates resulting from interest rate liberalisation may increase the likelihood of financial crises by encouraging risk-taking on the part of banks in an attempt to take advantage of higher returns. Authorities in most countries have reduced interest rates in an attempt to boost aggregate demand, which is expected to speed up the recovery from the crisis. However, the lowering of interest rates may result in a decrease in savings and investments, which are the main drivers of long-term economic growth. Real interest rates below equilibrium may encourage banks to take more risks in their lending practices in order to earn higher returns which may result in an increase in non-performing loans. The influence of interest rates on financial crises has thus received considerable attention since the onset of the 2008-’09 global financial crisis and this thesis contributes to the literature by determining how interest rates impact on economic growth in SADC countries and whether interest rate liberalisation increases the likelihood of financial crises. The study examines the relationship between interest rate liberalisation and economic growth through different channels. These include savings and investments, capital flows and finan-cial development. The study uses the Pooled Mean Group (PMG) estimator proposed by Pesaran et al (1999) to estimate the effect of interest rate liberalisation on economic growth through the abovementioned channels. The study also examines whether interest rate liberalisation increases the likelihood of financial crises. This is estimated using the logit model, due to the binary nature of the dependent variable. The results provide limited support for the McKinnon and Shaw hypothesis. Interest rate liberalisation has a positive effect on economic growth through higher savings and investments. Interest rate liberalisation has a positive outcome on capital inflows, which indicates that the prospect of earning higher returns encourages foreign investors to invest in the domestic economy. However, capital inflows do not enhance economic growth. This could be due to the low levels of human capital in SADC countries. Interest rate liberalisation boosts financial development through higher savings and invest-ments. However, financial development has a negative effect on economic growth because of the link between financial development and financial crises. The results show that interest rate liberalisation decreases the likelihood of financial crises directly, however, it increases the probability of financial crises indirectly through financial development. This suggests that the major cause of financial crises in the region is the low levels of institutional quality and lack of adequate supervisory frameworks to monitor the functioning of the financial system. Therefore, the results imply that the negative impact of interest rate liberalisation may outweigh the positive effect of higher savings and investments in SADC countries. A number of policy recommendations can be drawn from the study. Liberalisation of interest rates has a positive effect on economic growth through savings and investments. However improving the levels of institutional quality is vital for preventing financial crises. Interest rate liberalisation may not have a direct influence on financial crises, but higher levels of fi-nancial development emanating from higher interest rates increase the likelihood of financial crises. Therefore, a sound monitoring framework is necessary for the benefits of financial liberalisation to be realised. Also, investment in education, training and research and development is a necessity so as to increase levels of human capital, which in turn may allow the region to reap the benefits of capital inflows.
- Full Text:
- Date Issued: 2018
- Authors: Moyo, Clement Zibusiso
- Date: 2018
- Subjects: Southern African Development Community , Economic development -- Africa, Southern Developing countries -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/22791 , vital:30087
- Description: The pioneers of financial liberalisation, McKinnon (1973) and Shaw (1973) argue that inter-est rates determined by market forces have a positive effect on economic growth rates. Inter-est rates that are kept at low levels through the intervention of a central bank discourage sav-ings and capital accumulation, and distort the allocation of resources. Interest rate liberalisa-tion results in higher real interest rates which could have a positive effect on savings, invest-ments and economic growth (Ang & McKibbin 2007). Interest rate liberalisation also reduces capital flight and encourages capital inflows by increasing return for investors which supple-ments domestic investments. Shaw (1973) argued that interest rate liberalisation promotes financial development by encouraging savings and increasing the availability of funds for lending purposes. The study provides an empirical analysis of the channels through which interest rate liberalisation impacts on economic growth in SADC countries for the period 1990 to 2015. The study is motivated by the concerns on the impact of interest rate liberalisation on eco-nomic growth in the period after the 2008-’09 global financial crisis as well as concerns that interest rate liberalisation increases the likelihood of financial crises. Higher interest rates resulting from interest rate liberalisation may increase the likelihood of financial crises by encouraging risk-taking on the part of banks in an attempt to take advantage of higher returns. Authorities in most countries have reduced interest rates in an attempt to boost aggregate demand, which is expected to speed up the recovery from the crisis. However, the lowering of interest rates may result in a decrease in savings and investments, which are the main drivers of long-term economic growth. Real interest rates below equilibrium may encourage banks to take more risks in their lending practices in order to earn higher returns which may result in an increase in non-performing loans. The influence of interest rates on financial crises has thus received considerable attention since the onset of the 2008-’09 global financial crisis and this thesis contributes to the literature by determining how interest rates impact on economic growth in SADC countries and whether interest rate liberalisation increases the likelihood of financial crises. The study examines the relationship between interest rate liberalisation and economic growth through different channels. These include savings and investments, capital flows and finan-cial development. The study uses the Pooled Mean Group (PMG) estimator proposed by Pesaran et al (1999) to estimate the effect of interest rate liberalisation on economic growth through the abovementioned channels. The study also examines whether interest rate liberalisation increases the likelihood of financial crises. This is estimated using the logit model, due to the binary nature of the dependent variable. The results provide limited support for the McKinnon and Shaw hypothesis. Interest rate liberalisation has a positive effect on economic growth through higher savings and investments. Interest rate liberalisation has a positive outcome on capital inflows, which indicates that the prospect of earning higher returns encourages foreign investors to invest in the domestic economy. However, capital inflows do not enhance economic growth. This could be due to the low levels of human capital in SADC countries. Interest rate liberalisation boosts financial development through higher savings and invest-ments. However, financial development has a negative effect on economic growth because of the link between financial development and financial crises. The results show that interest rate liberalisation decreases the likelihood of financial crises directly, however, it increases the probability of financial crises indirectly through financial development. This suggests that the major cause of financial crises in the region is the low levels of institutional quality and lack of adequate supervisory frameworks to monitor the functioning of the financial system. Therefore, the results imply that the negative impact of interest rate liberalisation may outweigh the positive effect of higher savings and investments in SADC countries. A number of policy recommendations can be drawn from the study. Liberalisation of interest rates has a positive effect on economic growth through savings and investments. However improving the levels of institutional quality is vital for preventing financial crises. Interest rate liberalisation may not have a direct influence on financial crises, but higher levels of fi-nancial development emanating from higher interest rates increase the likelihood of financial crises. Therefore, a sound monitoring framework is necessary for the benefits of financial liberalisation to be realised. Also, investment in education, training and research and development is a necessity so as to increase levels of human capital, which in turn may allow the region to reap the benefits of capital inflows.
- Full Text:
- Date Issued: 2018
Interrogating teacher leadership development through a formative intervention: a case study in a rural Secondary School in northern Namibia
- Authors: Iyambo, David Kandiwapa
- Date: 2018
- Subjects: Educational leadership -- Namibia , School management and organization -- Namibia , Teachers -- Training of -- Namibia , Cultural Historical Activity Theory
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/61547 , vital:28035
- Description: The Namibian education system has undergone major policy shifts from a ‘top-down’ hierarchical leadership practice to a more shared and democratic form of leadership in schools. These policies compel principals and school management team members to involve level-one teachers in decision-making and other leadership roles within their schools and beyond. However, to this end, the goals envisaged by policies for teachers to participate in, and contribute to the overall school leadership activities and decision-making have not been fully realised. This was due to the inherent hierarchy of the ‘top-down’ system and autocratic leadership style which remains powerful within the current school practice. Against this backdrop, this study interrogated how teacher leadership can be developed in a rural Secondary School in northern Namibia. The underlying cultural-historical conditions that promoted or constrained teacher leadership development were surfaced. Opportunities for changes in leadership practices through a formative intervention were developed. Cultural Historical Activity Theory (CHAT) was utilised as a theoretical and analytical framework in this study together with Grant’s Model of Teacher Leadership (2006; 2008; 2010). Five level-one teachers, two school management members and a school board chairperson were selected as research participants by means of a purposive sampling method. Furthermore, the study used document analysis, semi-structured interviews, questionnaires and change laboratory workshops as main tools for data generation. The findings revealed that participants understood the concept of teacher leadership differently and that teachers in the case study school were leading in all four zones of teacher leadership model (Grant, 2006; 2008; 2012) although their roles differed. However, the study also found that teacher leadership development was mostly intensified by managerial structures. It appeared from the findings of this study that conditions such as the role of the school management team (SMT) members in promoting teacher leadership development, a supportive organisational culture, and provision of learning support amongst staff members through the attendance of workshops emerged as factors promoting the development of teachers as leaders. The study also revealed that there were many cultural and historical tensions that constrained the practice of teacher leadership development in school. Thus, the study argues that limited leadership training and an inherent ‘top-down’ hierarchical style of leadership was the main underlying systemic causes that constrained teachers to be developed as leaders. Through the change laboratory workshops, the findings suggested that there was a need for continuous professional development initiatives and leadership training, as alternative way for the realisation of teacher leadership development. Finally, a recommendation that leadership aspects should be constituted in pre-and in-service professional development training as an ongoing practice is made.
- Full Text:
- Date Issued: 2018
- Authors: Iyambo, David Kandiwapa
- Date: 2018
- Subjects: Educational leadership -- Namibia , School management and organization -- Namibia , Teachers -- Training of -- Namibia , Cultural Historical Activity Theory
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/61547 , vital:28035
- Description: The Namibian education system has undergone major policy shifts from a ‘top-down’ hierarchical leadership practice to a more shared and democratic form of leadership in schools. These policies compel principals and school management team members to involve level-one teachers in decision-making and other leadership roles within their schools and beyond. However, to this end, the goals envisaged by policies for teachers to participate in, and contribute to the overall school leadership activities and decision-making have not been fully realised. This was due to the inherent hierarchy of the ‘top-down’ system and autocratic leadership style which remains powerful within the current school practice. Against this backdrop, this study interrogated how teacher leadership can be developed in a rural Secondary School in northern Namibia. The underlying cultural-historical conditions that promoted or constrained teacher leadership development were surfaced. Opportunities for changes in leadership practices through a formative intervention were developed. Cultural Historical Activity Theory (CHAT) was utilised as a theoretical and analytical framework in this study together with Grant’s Model of Teacher Leadership (2006; 2008; 2010). Five level-one teachers, two school management members and a school board chairperson were selected as research participants by means of a purposive sampling method. Furthermore, the study used document analysis, semi-structured interviews, questionnaires and change laboratory workshops as main tools for data generation. The findings revealed that participants understood the concept of teacher leadership differently and that teachers in the case study school were leading in all four zones of teacher leadership model (Grant, 2006; 2008; 2012) although their roles differed. However, the study also found that teacher leadership development was mostly intensified by managerial structures. It appeared from the findings of this study that conditions such as the role of the school management team (SMT) members in promoting teacher leadership development, a supportive organisational culture, and provision of learning support amongst staff members through the attendance of workshops emerged as factors promoting the development of teachers as leaders. The study also revealed that there were many cultural and historical tensions that constrained the practice of teacher leadership development in school. Thus, the study argues that limited leadership training and an inherent ‘top-down’ hierarchical style of leadership was the main underlying systemic causes that constrained teachers to be developed as leaders. Through the change laboratory workshops, the findings suggested that there was a need for continuous professional development initiatives and leadership training, as alternative way for the realisation of teacher leadership development. Finally, a recommendation that leadership aspects should be constituted in pre-and in-service professional development training as an ongoing practice is made.
- Full Text:
- Date Issued: 2018
Introduction to the special issue: applied critical realism in the social sciences
- Authors: Price, Leigh , Martin, Lee
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392133 , vital:68724 , xlink:href="https://doi.org/10.1080/14767430.2018.1468148"
- Description: The aim of our initial call for papers was to encourage the submission of exemplars of applied work, reflections on the use of critical realism, and metatheoretical developments. We were not disappointed, and we are therefore pleased to present this collection of five articles which advance our understanding of critical realism in practice. The book review in this issue further extends the collection, as it summarizes several examples of applied critical realist work. As one would expect of such a collection, there are a variety of disciplines represented, from business studies, to marketing, psychology, law and education. In this editorial, we provide an overview of the (concrete universal) trends of current applications of critical realism of which these articles are (concrete singular, and therefore unique) instantiations. Finally, we provide a brief introduction to each paper. We expect that the audience for this issue may be broader than, though still include, the usual readership of Journal of Critical Realism. Specifically, we expect to attract early career researchers who are new to critical realist ideas, and people whose primary interest is directed at one of the disciplines represented, rather than critical realism per se. For this reason, at the risk of repetition, we have allowed several of the authors to outline the aspects of critical realism that are relevant to their paper.
- Full Text:
- Date Issued: 2018
- Authors: Price, Leigh , Martin, Lee
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392133 , vital:68724 , xlink:href="https://doi.org/10.1080/14767430.2018.1468148"
- Description: The aim of our initial call for papers was to encourage the submission of exemplars of applied work, reflections on the use of critical realism, and metatheoretical developments. We were not disappointed, and we are therefore pleased to present this collection of five articles which advance our understanding of critical realism in practice. The book review in this issue further extends the collection, as it summarizes several examples of applied critical realist work. As one would expect of such a collection, there are a variety of disciplines represented, from business studies, to marketing, psychology, law and education. In this editorial, we provide an overview of the (concrete universal) trends of current applications of critical realism of which these articles are (concrete singular, and therefore unique) instantiations. Finally, we provide a brief introduction to each paper. We expect that the audience for this issue may be broader than, though still include, the usual readership of Journal of Critical Realism. Specifically, we expect to attract early career researchers who are new to critical realist ideas, and people whose primary interest is directed at one of the disciplines represented, rather than critical realism per se. For this reason, at the risk of repetition, we have allowed several of the authors to outline the aspects of critical realism that are relevant to their paper.
- Full Text:
- Date Issued: 2018
Introduction: Blurring Boundaries
- Mnyaka, Phindezwa, Macleod, Catriona I
- Authors: Mnyaka, Phindezwa , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434252 , vital:73042 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_9
- Description: This chapter introduces the section on blurring boundaries in research. The chapters within this section unpack the ethical dilemmas that researchers negotiate when they find themselves stepping outside their roles as researchers in the field. Research encounters presuppose particular boundaries, depending on the methodology employed and the research questions posed. However, participants may identify researchers differently, compelling them to respond in unanticipated ways as possibly therapists, clinicians, interlocutors, and activists. Collectively, the authors of the chapters in this section explore the ethical implications of blurring such boundaries. They unpack the significance of various forms of intimacies that may emerge while undertaking research, how researchers are positioned as agents of social change, and how researchers negotiate their statuses as insiders and outsiders in fieldwork.
- Full Text:
- Date Issued: 2018
- Authors: Mnyaka, Phindezwa , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434252 , vital:73042 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_9
- Description: This chapter introduces the section on blurring boundaries in research. The chapters within this section unpack the ethical dilemmas that researchers negotiate when they find themselves stepping outside their roles as researchers in the field. Research encounters presuppose particular boundaries, depending on the methodology employed and the research questions posed. However, participants may identify researchers differently, compelling them to respond in unanticipated ways as possibly therapists, clinicians, interlocutors, and activists. Collectively, the authors of the chapters in this section explore the ethical implications of blurring such boundaries. They unpack the significance of various forms of intimacies that may emerge while undertaking research, how researchers are positioned as agents of social change, and how researchers negotiate their statuses as insiders and outsiders in fieldwork.
- Full Text:
- Date Issued: 2018
Introduction: On (still) rediscovering the ordinary
- Authors: Wessels, Paul
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458513 , vital:75750 , https://hdl.handle.net/10520/EJC-1061aba2b5
- Description: The essays included in this special issue of English in Africa are written by published writers of fiction and poetry who have close ties to academic departments as teachers, writers, scholars and editors. While they are scholarly in form, these articles seek to evoke a broader range of response than the purely academic, and for this reason they may not always strictly follow academic conventions. For example, to preserve the flow of the discussion parenthetical references may, at times, have been excluded, and ‘creative’ poetry and prose are often drawn into the argument for effect. We hope that the tone of the keynote address, while it has been abridged and edited for print, remains conversational and anecdotal, in keeping with its oral delivery.
- Full Text:
- Date Issued: 2018
- Authors: Wessels, Paul
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458513 , vital:75750 , https://hdl.handle.net/10520/EJC-1061aba2b5
- Description: The essays included in this special issue of English in Africa are written by published writers of fiction and poetry who have close ties to academic departments as teachers, writers, scholars and editors. While they are scholarly in form, these articles seek to evoke a broader range of response than the purely academic, and for this reason they may not always strictly follow academic conventions. For example, to preserve the flow of the discussion parenthetical references may, at times, have been excluded, and ‘creative’ poetry and prose are often drawn into the argument for effect. We hope that the tone of the keynote address, while it has been abridged and edited for print, remains conversational and anecdotal, in keeping with its oral delivery.
- Full Text:
- Date Issued: 2018
Introduction: The politics of anonymity and confidentiality
- Macleod, Catriona I, Mnyaka, Phindezwa
- Authors: Macleod, Catriona I , Mnyaka, Phindezwa
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434237 , vital:73041 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_15
- Description: Ethics committees standardly require that the researchers address questions concerning anonymity and confidentiality. The conventional practice is to ensure that participants’ names and identifying details are expunged from public records of the research and that high levels of confidentiality of data are maintained in the research process. In this introduction, we outline how authors of chapters in this section ask questions concerning these imperatives, including circumstances where participants actively want their identity revealed and their voice heard or when anonymising might not be possible or may further disadvantage marginalised populations. We explore the argument made by authors that the automatic anonymising of data and the imposition of confidentiality can constrain ethical conduct.
- Full Text:
- Date Issued: 2018
- Authors: Macleod, Catriona I , Mnyaka, Phindezwa
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434237 , vital:73041 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_15
- Description: Ethics committees standardly require that the researchers address questions concerning anonymity and confidentiality. The conventional practice is to ensure that participants’ names and identifying details are expunged from public records of the research and that high levels of confidentiality of data are maintained in the research process. In this introduction, we outline how authors of chapters in this section ask questions concerning these imperatives, including circumstances where participants actively want their identity revealed and their voice heard or when anonymising might not be possible or may further disadvantage marginalised populations. We explore the argument made by authors that the automatic anonymising of data and the imposition of confidentiality can constrain ethical conduct.
- Full Text:
- Date Issued: 2018
Invaded habitat incompatibility affects the suitability of the potential biological control agent Listronotus sordidus for Sagittaria platyphylla in South Africa
- Martin, Grant D, Coetzee, Julie A, Lloyd, Melissa, Nombewu, Sinoxolo E, Ndlovu, Mpilonhle S, Kwong, Raelene M
- Authors: Martin, Grant D , Coetzee, Julie A , Lloyd, Melissa , Nombewu, Sinoxolo E , Ndlovu, Mpilonhle S , Kwong, Raelene M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103926 , vital:32323 , https://doi.org/10.1080/09583157.2018.1460314
- Description: Sagittaria platyphylla (Engelmann) J.G. Smith (Alismataceae) was first recorded in South Africa in 2008 and is considered to be an emerging weed with naturalised populations occurring throughout the country. A biological control programme was initiated in Australia and surveys conducted between 2010 and 2012 yielded potential agents, including the crown feeding weevil, Listronotus sordidus Gyllenhal (Coleoptera: Curculionidae). The potential of L. sordidus as a candidate biological control agent against S. platyphylla in South Africa was examined. Although adult feeding was recorded on a number of plant species, oviposition and larval development indicated a narrow host range restricted to the Alismataceae. In South Africa, S. platyphylla populations are primarily found in inundated systems. However, laboratory studies showed that L. sordidus did not oviposit on inundated plants, potentially nullifying the impact of the insect on South African populations. It is suggested that even though L. sordidus is a damaging, specific agent, its limited impact on inundated plant populations in South Africa does not justify the inherent risk associated with the release of a biological control agent.
- Full Text: false
- Date Issued: 2018
- Authors: Martin, Grant D , Coetzee, Julie A , Lloyd, Melissa , Nombewu, Sinoxolo E , Ndlovu, Mpilonhle S , Kwong, Raelene M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103926 , vital:32323 , https://doi.org/10.1080/09583157.2018.1460314
- Description: Sagittaria platyphylla (Engelmann) J.G. Smith (Alismataceae) was first recorded in South Africa in 2008 and is considered to be an emerging weed with naturalised populations occurring throughout the country. A biological control programme was initiated in Australia and surveys conducted between 2010 and 2012 yielded potential agents, including the crown feeding weevil, Listronotus sordidus Gyllenhal (Coleoptera: Curculionidae). The potential of L. sordidus as a candidate biological control agent against S. platyphylla in South Africa was examined. Although adult feeding was recorded on a number of plant species, oviposition and larval development indicated a narrow host range restricted to the Alismataceae. In South Africa, S. platyphylla populations are primarily found in inundated systems. However, laboratory studies showed that L. sordidus did not oviposit on inundated plants, potentially nullifying the impact of the insect on South African populations. It is suggested that even though L. sordidus is a damaging, specific agent, its limited impact on inundated plant populations in South Africa does not justify the inherent risk associated with the release of a biological control agent.
- Full Text: false
- Date Issued: 2018
Investigating a new wealth tax in South Africa: Lessons from international experience
- Arendse, Jacqueline A, Stack, Elizabeth M
- Authors: Arendse, Jacqueline A , Stack, Elizabeth M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69434 , vital:29536 , https://jefjournal.org.za/index.php/jef/article/view/175/193
- Description: In recent years, there has been an increasing focus on new sources of taxation, including wealth tax. In South Africa, two phenomena have driven the focus on wealth tax. Firstly, the need for additional tax revenue to fund an ongoing and growing budget deficit, exacerbated by a prolonged period of low economic growth, rising government debt and a very small base of individual taxpayers. Secondly, the fact that South Africa has one of the most unequal societies in the world. The dual demands of increased tax revenue and economic inequality have converged around wealth tax as a possible panacea to both problems. Although South Africa has a long history of wealth transfer tax in the form of estate duty and donations tax, there has never been a tax on the net wealth holdings of individuals during their lifetime. Internationally, numerous countries have used wealth tax in various forms, including inheritance tax, gift tax, recurrent wealth tax and non-recurrent wealth tax. This study examines some of the international experiences with these three categories of wealth tax, seeking lessons and experiences that can inform the debate around the viability of a new wealth tax in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Arendse, Jacqueline A , Stack, Elizabeth M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69434 , vital:29536 , https://jefjournal.org.za/index.php/jef/article/view/175/193
- Description: In recent years, there has been an increasing focus on new sources of taxation, including wealth tax. In South Africa, two phenomena have driven the focus on wealth tax. Firstly, the need for additional tax revenue to fund an ongoing and growing budget deficit, exacerbated by a prolonged period of low economic growth, rising government debt and a very small base of individual taxpayers. Secondly, the fact that South Africa has one of the most unequal societies in the world. The dual demands of increased tax revenue and economic inequality have converged around wealth tax as a possible panacea to both problems. Although South Africa has a long history of wealth transfer tax in the form of estate duty and donations tax, there has never been a tax on the net wealth holdings of individuals during their lifetime. Internationally, numerous countries have used wealth tax in various forms, including inheritance tax, gift tax, recurrent wealth tax and non-recurrent wealth tax. This study examines some of the international experiences with these three categories of wealth tax, seeking lessons and experiences that can inform the debate around the viability of a new wealth tax in South Africa.
- Full Text:
- Date Issued: 2018
Investigating combinations of feature extraction and classification for improved image-based multimodal biometric systems at the feature level
- Authors: Brown, Dane L
- Date: 2018
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63470 , vital:28414
- Description: Multimodal biometrics has become a popular means of overcoming the limitations of unimodal biometric systems. However, the rich information particular to the feature level is of a complex nature and leveraging its potential without overfitting a classifier is not well studied. This research investigates feature-classifier combinations on the fingerprint, face, palmprint, and iris modalities to effectively fuse their feature vectors for a complementary result. The effects of different feature-classifier combinations are thus isolated to identify novel or improved algorithms. A new face segmentation algorithm is shown to increase consistency in nominal and extreme scenarios. Moreover, two novel feature extraction techniques demonstrate better adaptation to dynamic lighting conditions, while reducing feature dimensionality to the benefit of classifiers. A comprehensive set of unimodal experiments are carried out to evaluate both verification and identification performance on a variety of datasets using four classifiers, namely Eigen, Fisher, Local Binary Pattern Histogram and linear Support Vector Machine on various feature extraction methods. The recognition performance of the proposed algorithms are shown to outperform the vast majority of related studies, when using the same dataset under the same test conditions. In the unimodal comparisons presented, the proposed approaches outperform existing systems even when given a handicap such as fewer training samples or data with a greater number of classes. A separate comprehensive set of experiments on feature fusion show that combining modality data provides a substantial increase in accuracy, with only a few exceptions that occur when differences in the image data quality of two modalities are substantial. However, when two poor quality datasets are fused, noticeable gains in recognition performance are realized when using the novel feature extraction approach. Finally, feature-fusion guidelines are proposed to provide the necessary insight to leverage the rich information effectively when fusing multiple biometric modalities at the feature level. These guidelines serve as the foundation to better understand and construct biometric systems that are effective in a variety of applications.
- Full Text:
- Date Issued: 2018
- Authors: Brown, Dane L
- Date: 2018
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63470 , vital:28414
- Description: Multimodal biometrics has become a popular means of overcoming the limitations of unimodal biometric systems. However, the rich information particular to the feature level is of a complex nature and leveraging its potential without overfitting a classifier is not well studied. This research investigates feature-classifier combinations on the fingerprint, face, palmprint, and iris modalities to effectively fuse their feature vectors for a complementary result. The effects of different feature-classifier combinations are thus isolated to identify novel or improved algorithms. A new face segmentation algorithm is shown to increase consistency in nominal and extreme scenarios. Moreover, two novel feature extraction techniques demonstrate better adaptation to dynamic lighting conditions, while reducing feature dimensionality to the benefit of classifiers. A comprehensive set of unimodal experiments are carried out to evaluate both verification and identification performance on a variety of datasets using four classifiers, namely Eigen, Fisher, Local Binary Pattern Histogram and linear Support Vector Machine on various feature extraction methods. The recognition performance of the proposed algorithms are shown to outperform the vast majority of related studies, when using the same dataset under the same test conditions. In the unimodal comparisons presented, the proposed approaches outperform existing systems even when given a handicap such as fewer training samples or data with a greater number of classes. A separate comprehensive set of experiments on feature fusion show that combining modality data provides a substantial increase in accuracy, with only a few exceptions that occur when differences in the image data quality of two modalities are substantial. However, when two poor quality datasets are fused, noticeable gains in recognition performance are realized when using the novel feature extraction approach. Finally, feature-fusion guidelines are proposed to provide the necessary insight to leverage the rich information effectively when fusing multiple biometric modalities at the feature level. These guidelines serve as the foundation to better understand and construct biometric systems that are effective in a variety of applications.
- Full Text:
- Date Issued: 2018
Investigating Grade 3 learners’ changing mathematical proficiency in a maths club programme focused on number sense progression
- Authors: Hebe, Gasenakeletso Ennie
- Date: 2018
- Subjects: Mathematical ability -- Testing , Education, Elementary -- South Africa , Mathematics -- Study and teaching (Elementary) -- Activity programs , Mathematics -- Remedial teaching , South African Numeracy Chair Project (SANCP)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62200 , vital:28137
- Description: Recent international reports, for example TIMSS (2011 & 2015), point to serious challenges in South African learner performance in Mathematics and Science. Of greatest concern is that research findings (e.g. Graven, Venkat, Westaway and Tshesane 2013) suggest that many South African learners show signs of mathematical knowledge gaps in the lower grades. Hence, there is a need to address challenges of this nature very early in Foundation Phase. This study was undertaken with a view to contribute towards addressing mathematical challenges encountered by learners in Foundation Phase. This empirical enquiry was undertaken under the auspices of the South African Numeracy Chair Project (SANCP) at Rhodes University whose mission is to develop sustainable ways of improving quality teaching and learning of Mathematics in South Africa. A relatively new SANCP programme called Pushing for Progression (PfP) run as part of the after-school Maths Clubs to develop the number sense and four Operations in learners was used to achieve the research aims of this study. Research participants were drawn from the Maths Clubs established by the researcher in a small rural town of Ottosdal in the North West Province of South Africa. This Study is grounded on the Vygotskian perspective and uses the interpretivist qualitative research method for data collection and analysis. Sampling was done opportunistically by enlisting participants (12 teachers and 117 learners) on the basis of their availability and willingness to participate. Pre- and post-assessment of learners’ proficiency on the four Basic Operations was conducted at the beginning and at the end of the research project, respectively. This was done to determine the impact of the project on learner performance. Data analysis was done thematically and through the comparison of learner results of the pre- and post-assessment. The findings point to the effectiveness of the PfP Programme in learner performance. This can be deduced from improved scores between pre- and post-assessment and the observations made by participant-teachers on their respective club learners’ mathematical proficiencies. Accordingly, based on the findings, this study recommends, inter alia, that since the PfP programme is still in its early stages, similar research be conducted elsewhere. Additionally, the Department of Basic Education could consider exploring the PfP programme as one of several other strategies to help improve learner proficiency in Mathematics.
- Full Text:
- Date Issued: 2018
- Authors: Hebe, Gasenakeletso Ennie
- Date: 2018
- Subjects: Mathematical ability -- Testing , Education, Elementary -- South Africa , Mathematics -- Study and teaching (Elementary) -- Activity programs , Mathematics -- Remedial teaching , South African Numeracy Chair Project (SANCP)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62200 , vital:28137
- Description: Recent international reports, for example TIMSS (2011 & 2015), point to serious challenges in South African learner performance in Mathematics and Science. Of greatest concern is that research findings (e.g. Graven, Venkat, Westaway and Tshesane 2013) suggest that many South African learners show signs of mathematical knowledge gaps in the lower grades. Hence, there is a need to address challenges of this nature very early in Foundation Phase. This study was undertaken with a view to contribute towards addressing mathematical challenges encountered by learners in Foundation Phase. This empirical enquiry was undertaken under the auspices of the South African Numeracy Chair Project (SANCP) at Rhodes University whose mission is to develop sustainable ways of improving quality teaching and learning of Mathematics in South Africa. A relatively new SANCP programme called Pushing for Progression (PfP) run as part of the after-school Maths Clubs to develop the number sense and four Operations in learners was used to achieve the research aims of this study. Research participants were drawn from the Maths Clubs established by the researcher in a small rural town of Ottosdal in the North West Province of South Africa. This Study is grounded on the Vygotskian perspective and uses the interpretivist qualitative research method for data collection and analysis. Sampling was done opportunistically by enlisting participants (12 teachers and 117 learners) on the basis of their availability and willingness to participate. Pre- and post-assessment of learners’ proficiency on the four Basic Operations was conducted at the beginning and at the end of the research project, respectively. This was done to determine the impact of the project on learner performance. Data analysis was done thematically and through the comparison of learner results of the pre- and post-assessment. The findings point to the effectiveness of the PfP Programme in learner performance. This can be deduced from improved scores between pre- and post-assessment and the observations made by participant-teachers on their respective club learners’ mathematical proficiencies. Accordingly, based on the findings, this study recommends, inter alia, that since the PfP programme is still in its early stages, similar research be conducted elsewhere. Additionally, the Department of Basic Education could consider exploring the PfP programme as one of several other strategies to help improve learner proficiency in Mathematics.
- Full Text:
- Date Issued: 2018
Investigating long-term host-parasite dynamics in odontocetes in Southern Africa
- Authors: Adams, Inge Alison
- Date: 2018
- Subjects: Biological invasions -- Environmental aspects , Cetacea -- Indian Ocean , Ecological disturbances
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23437 , vital:30543
- Description: Cetaceans are a very diverse family and globally, various aspects about their biology have been studied, including infection by parasites. Twenty-five dolphin species can be found in the South African subregion and very little information is available detailing which parasites are infecting them. Parasite samples have been collected opportunistically since the 1970’s from dolphins incidentally caught in shark nets off the KwaZulu-Natal coastline as well as from dolphins stranded along the Eastern Cape coastline. These samples have been stored in the Graham Ross Marine Mammal Collection at the Port Elizabeth Museum and samples belonging to eight odontocete species have been used in the present analysis. These eight species are: the Indian Ocean Humpback Dolphin (Sousa plumbea), the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus), the Long-beaked Common Dolphin (Delphinus capensis), the Risso’s Dolphin (Grampus griseus), the Pantropical Spotted Dolphin (Stenella attenuata), the Striped Dolphin (Stenella coeruleoalba), the Pygmy Sperm Whale (Kogia breviceps) and the Dwarf Sperm Whale (Kogia breviceps). This study aims to investigate which parasites are infecting odontocetes in Southern Africa. Secondly, this study aims to investigate whether any trends in infection exist between sexes, age groups, cause of death and over time. Eighteen parasite species were found to infect odontocetes in Southern Africa. Two could only be identified to family level, seven to genus level and eight to species level. Only one parasite, a trematode, could not be identified and several parasite species were new host records for the subregion. Results showed that the prevalence of parasitic infection has increased over the last four decades, prompting questions regarding the health of our oceans. This study is the first to comprehensively investigate which parasite species are found in these eight odontocete species in Southern Africa. This baseline data will contribute greatly to other types of research involving parasites and provides us with information regarding the health of our ocean.
- Full Text:
- Date Issued: 2018
- Authors: Adams, Inge Alison
- Date: 2018
- Subjects: Biological invasions -- Environmental aspects , Cetacea -- Indian Ocean , Ecological disturbances
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23437 , vital:30543
- Description: Cetaceans are a very diverse family and globally, various aspects about their biology have been studied, including infection by parasites. Twenty-five dolphin species can be found in the South African subregion and very little information is available detailing which parasites are infecting them. Parasite samples have been collected opportunistically since the 1970’s from dolphins incidentally caught in shark nets off the KwaZulu-Natal coastline as well as from dolphins stranded along the Eastern Cape coastline. These samples have been stored in the Graham Ross Marine Mammal Collection at the Port Elizabeth Museum and samples belonging to eight odontocete species have been used in the present analysis. These eight species are: the Indian Ocean Humpback Dolphin (Sousa plumbea), the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus), the Long-beaked Common Dolphin (Delphinus capensis), the Risso’s Dolphin (Grampus griseus), the Pantropical Spotted Dolphin (Stenella attenuata), the Striped Dolphin (Stenella coeruleoalba), the Pygmy Sperm Whale (Kogia breviceps) and the Dwarf Sperm Whale (Kogia breviceps). This study aims to investigate which parasites are infecting odontocetes in Southern Africa. Secondly, this study aims to investigate whether any trends in infection exist between sexes, age groups, cause of death and over time. Eighteen parasite species were found to infect odontocetes in Southern Africa. Two could only be identified to family level, seven to genus level and eight to species level. Only one parasite, a trematode, could not be identified and several parasite species were new host records for the subregion. Results showed that the prevalence of parasitic infection has increased over the last four decades, prompting questions regarding the health of our oceans. This study is the first to comprehensively investigate which parasite species are found in these eight odontocete species in Southern Africa. This baseline data will contribute greatly to other types of research involving parasites and provides us with information regarding the health of our ocean.
- Full Text:
- Date Issued: 2018
Investigating the experiences of grade 8 English first additional language learners within an English home language classroom: a case study
- Authors: Abader, Naadirah
- Date: 2018
- Subjects: Language and languages -- Study and teaching -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: http://hdl.handle.net/10948/22662 , vital:30050
- Description: Teaching English home language (EHL) to a classroom of learners who are predominantly from another mother tongue context is a complex process because of the challenges faced by the learners. They struggle to cope with the demands of the EHL classroom, especially when their mother tongue is not recognized within the classroom context, as they move between different linguistic spaces. Despite their diverse identities, English language teachers continue to apply the linguistic approach of English only. This study was aimed at investigating the ways in which the experiences of non-mother tongue speakers in the EHL classroom affect the identities of these learners. Through a qualitative approach using photovoice with learners an attempt was made to probe their experiences of bringing other languages into an English home language classroom. Participants included 33 Grade 8 learners and their four English teachers from Taah High School in Nelson Mandela Bay. The findings have implications for the way in which diverse linguistic learners are taught in an EHL classroom, as the space that caged and rendered learner participants voiceless because they are not allowed to draw on their mother tongue linguistic repertoires, were changed. Learners mentioned that their teachers do not acknowledge the identity that each of them brings to the classroom.
- Full Text:
- Date Issued: 2018
- Authors: Abader, Naadirah
- Date: 2018
- Subjects: Language and languages -- Study and teaching -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: http://hdl.handle.net/10948/22662 , vital:30050
- Description: Teaching English home language (EHL) to a classroom of learners who are predominantly from another mother tongue context is a complex process because of the challenges faced by the learners. They struggle to cope with the demands of the EHL classroom, especially when their mother tongue is not recognized within the classroom context, as they move between different linguistic spaces. Despite their diverse identities, English language teachers continue to apply the linguistic approach of English only. This study was aimed at investigating the ways in which the experiences of non-mother tongue speakers in the EHL classroom affect the identities of these learners. Through a qualitative approach using photovoice with learners an attempt was made to probe their experiences of bringing other languages into an English home language classroom. Participants included 33 Grade 8 learners and their four English teachers from Taah High School in Nelson Mandela Bay. The findings have implications for the way in which diverse linguistic learners are taught in an EHL classroom, as the space that caged and rendered learner participants voiceless because they are not allowed to draw on their mother tongue linguistic repertoires, were changed. Learners mentioned that their teachers do not acknowledge the identity that each of them brings to the classroom.
- Full Text:
- Date Issued: 2018
Investigating the influence of ring substitution on indole hydrogen bonding, with amino acids
- Authors: Nel, Donovan
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63509 , vital:28426
- Description: Expected release date-April 2019
- Full Text: false
- Date Issued: 2018
- Authors: Nel, Donovan
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63509 , vital:28426
- Description: Expected release date-April 2019
- Full Text: false
- Date Issued: 2018
Investigating the levels of management and leadership development among medical doctors
- Authors: Mdingi, Simphiwe Lukhanyo
- Date: 2018
- Subjects: Leadership -- South Africa -- Research
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22957 , vital:30154
- Description: Private medical practice, as a division of primary healthcare, involves profitable medical practices and businesses owned and run by qualified medical practitioners that provide a healthcare service to their community. It is thus inevitable that the function of management forms a vital part of the medical practitioner’s responsibilities and entails daily, weekly and monthly duties such as training and managing staff members, general administration, ordering medical supplies, liaising with patients, clients and suppliers, generating accurate invoices, paying bills, wages and salaries, handling debtors and creditors; as well as many other tasks aimed at ensuring that his/her medical practice runs smoothly and cost effectively while continuing to focus on growing its patient/client base and income generating capabilities. Therefore, competent and effective management and leadership skills are essential to the success of a private medical practice and healthcare department at large, that will be able to provide its community with a healthcare service marked by excellence; contributing not only to its community’s employment rate and economy, but also to the general well being of its members. The treatise has identified that, although the medical industry in South Africa has invested heavily in the academic, clinical and practical development and training of medical practitioners and healthcare personnel in the past, many gaps exist in adequately equipping medical practitioners and other healthcare professionals with leadership skills aimed at the successful management of their private practices, healthcare departments and hospitals at large. With a view to bridge these gaps, it has been the main purpose of this study to identify the primary and specific factors that contribute to the lack of leadership and management development among medical practitioners in private practice. The empirical study included data collected via the distribution of a self-administered online survey among 100 medical practitioners in private practice and in management positions in the Western Cape area. The findings generated by the survey indicate that the level of management and leadership development among medical doctors in private practice in western cape is low mainly due to the current academic curriculum for medical doctors, lack of relevant, contemporary information regarding effective management and leadership development training for medical practitioners, lack of clinical leadership development and training, lack of suitable, available leadership and management mentoring/coaching for medical practitioners, as well as the medical profession’s neglect of conveying and imprinting the importance of the need for medical practitioners’ to acquire and become equipped with these skills. In light of these findings, a framework for management and leadership skills development among medical practitioners was constructed for consideration by policy makers, accompanied by recommendations aimed at actioning improvements that will positively impact the healthcare industry at large.
- Full Text:
- Date Issued: 2018
- Authors: Mdingi, Simphiwe Lukhanyo
- Date: 2018
- Subjects: Leadership -- South Africa -- Research
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22957 , vital:30154
- Description: Private medical practice, as a division of primary healthcare, involves profitable medical practices and businesses owned and run by qualified medical practitioners that provide a healthcare service to their community. It is thus inevitable that the function of management forms a vital part of the medical practitioner’s responsibilities and entails daily, weekly and monthly duties such as training and managing staff members, general administration, ordering medical supplies, liaising with patients, clients and suppliers, generating accurate invoices, paying bills, wages and salaries, handling debtors and creditors; as well as many other tasks aimed at ensuring that his/her medical practice runs smoothly and cost effectively while continuing to focus on growing its patient/client base and income generating capabilities. Therefore, competent and effective management and leadership skills are essential to the success of a private medical practice and healthcare department at large, that will be able to provide its community with a healthcare service marked by excellence; contributing not only to its community’s employment rate and economy, but also to the general well being of its members. The treatise has identified that, although the medical industry in South Africa has invested heavily in the academic, clinical and practical development and training of medical practitioners and healthcare personnel in the past, many gaps exist in adequately equipping medical practitioners and other healthcare professionals with leadership skills aimed at the successful management of their private practices, healthcare departments and hospitals at large. With a view to bridge these gaps, it has been the main purpose of this study to identify the primary and specific factors that contribute to the lack of leadership and management development among medical practitioners in private practice. The empirical study included data collected via the distribution of a self-administered online survey among 100 medical practitioners in private practice and in management positions in the Western Cape area. The findings generated by the survey indicate that the level of management and leadership development among medical doctors in private practice in western cape is low mainly due to the current academic curriculum for medical doctors, lack of relevant, contemporary information regarding effective management and leadership development training for medical practitioners, lack of clinical leadership development and training, lack of suitable, available leadership and management mentoring/coaching for medical practitioners, as well as the medical profession’s neglect of conveying and imprinting the importance of the need for medical practitioners’ to acquire and become equipped with these skills. In light of these findings, a framework for management and leadership skills development among medical practitioners was constructed for consideration by policy makers, accompanied by recommendations aimed at actioning improvements that will positively impact the healthcare industry at large.
- Full Text:
- Date Issued: 2018
Investigating the viability and performance of a pilot scale Fly Ash/Lime Filter Tower (FLFT) for greywater treatment and the fate of Triclosan post treatment
- Authors: Nondlazi, Sinoyolo
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63704 , vital:28473
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
- Authors: Nondlazi, Sinoyolo
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63704 , vital:28473
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Investigating thermal physiology as a tool to improve the release efficacy of insect biological control agents
- Authors: Griffith, Tamzin Camilla
- Date: 2018
- Subjects: Aquatic weeds -- Biological control , Water hyacinth -- Biological control , Insects -- Physiology , Miridae -- Effect of low temperatures on , Cold adaptation , Insects as biological pest control agents , Eccritotarsus catarinensis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63301 , vital:28391
- Description: Biological control is commonly used for the control of invasive aquatic weeds, which often involves the release of multiple host-specific agents. Releasing multiple agents has inherent safety concerns as the introduction of each new agent is associated with risks, but is often required to improve control where establishment is limited. Climatic incompatibility between the agent’s thermal physiology and its introduced range often causes agents to fail to establish. However, it has been suggested that the thermal physiology of insects is plastic. Therefore, the potential to manipulate their thermal physiologies before releasing them into the field needs to be explored; reducing the need to release additional agents, thereby ensuring the safety of biological control. This thesis therefore aimed to firstly, determine whether season and locality influenced the thermal physiology of two field populations of a water hyacinth (Eichhornia crassipes) control agent, the mirid Eccritotarsus catarinensis; one collected from the hottest establishment site, and one collected from the coldest establishment site in South Africa. Their thermal physiology was significantly influenced by season and not by the sites’ climate, suggesting their thermal physiology is plastic under field conditions. Secondly, the classical method of determining the lower critical thermal limit (CTmin), and a new respirometry method of determining this limit, compared the thermal physiology of two Eccritotarsus species reared in quarantine. Eccritotarsus catarinensis was significantly more cold tolerant than the more recently released Eccritotarsus eichhorniae, despite similar maintenance conditions, and as such, was used to establish whether cold hardening under laboratory conditions was possible. Successfully cold hardened E. catarinensis had a significantly lower CTmin compared to the field cold acclimated population, suggesting that cold hardening of agents could be conducted before release to improve their cold tolerance and increase their chances of establishment, allowing for further adaptation to colder climates in the field to occur. Increasing establishment of the most effective agents will decrease the number of agents needed in a biological control programme, thus encouraging a more parsimonious approach to biological control.
- Full Text:
- Date Issued: 2018
- Authors: Griffith, Tamzin Camilla
- Date: 2018
- Subjects: Aquatic weeds -- Biological control , Water hyacinth -- Biological control , Insects -- Physiology , Miridae -- Effect of low temperatures on , Cold adaptation , Insects as biological pest control agents , Eccritotarsus catarinensis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63301 , vital:28391
- Description: Biological control is commonly used for the control of invasive aquatic weeds, which often involves the release of multiple host-specific agents. Releasing multiple agents has inherent safety concerns as the introduction of each new agent is associated with risks, but is often required to improve control where establishment is limited. Climatic incompatibility between the agent’s thermal physiology and its introduced range often causes agents to fail to establish. However, it has been suggested that the thermal physiology of insects is plastic. Therefore, the potential to manipulate their thermal physiologies before releasing them into the field needs to be explored; reducing the need to release additional agents, thereby ensuring the safety of biological control. This thesis therefore aimed to firstly, determine whether season and locality influenced the thermal physiology of two field populations of a water hyacinth (Eichhornia crassipes) control agent, the mirid Eccritotarsus catarinensis; one collected from the hottest establishment site, and one collected from the coldest establishment site in South Africa. Their thermal physiology was significantly influenced by season and not by the sites’ climate, suggesting their thermal physiology is plastic under field conditions. Secondly, the classical method of determining the lower critical thermal limit (CTmin), and a new respirometry method of determining this limit, compared the thermal physiology of two Eccritotarsus species reared in quarantine. Eccritotarsus catarinensis was significantly more cold tolerant than the more recently released Eccritotarsus eichhorniae, despite similar maintenance conditions, and as such, was used to establish whether cold hardening under laboratory conditions was possible. Successfully cold hardened E. catarinensis had a significantly lower CTmin compared to the field cold acclimated population, suggesting that cold hardening of agents could be conducted before release to improve their cold tolerance and increase their chances of establishment, allowing for further adaptation to colder climates in the field to occur. Increasing establishment of the most effective agents will decrease the number of agents needed in a biological control programme, thus encouraging a more parsimonious approach to biological control.
- Full Text:
- Date Issued: 2018