The implications of rural-urban migration on employment and household income with particular reference to Lesotho
- Authors: Damane, Moeti
- Date: 2012
- Subjects: Rural-urban migration -- Employment -- Lesotho Informal sector (Economics) -- Lesotho Lesotho -- Economic conditions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1002 , http://hdl.handle.net/10962/d1002737
- Description: The research investigates the impact of internal rural - urban migration III Lesotho on household income and employment. Using data gathered from the 2002/03 household survey, the 2006 nationwide census and a questionnaire on rural - urban migration in Lesotho administered to 500 respondents in Maseru and Leribe, we estimate a logit model of the probability of employment in Lesotho in 2008 given a set of independent variables. The independent variables are respondent's work experience; years of education completed; employment status in 2004; employment status in 2008; gender; job skill level; place of residence in 2004 and a categorical variable that measures whether or not the respondent is a rural - urban migrant. The results suggest that migration and work experience have no significant impact on an individual's likelihood of being employed in the country's formal sector. Also, it was found that the higher the level of education an individual has, the less likely are their chances of employment in the country's formal sector because of the lack of formal jobs in the urban areas. Over 50% of Lesotho's workforce employed in the urban areas was discovered to work in the informal sector. The study concludes that there is a lack of jobs in Lesotho's urban formal sector that results in a thriving informal sector. The advantages of informal sector jobs to the rural - urban migrant include an increase in their standard of living as well as that of their family members left behind in the rural areas but the disadvantages include low levels of investor confidence that lead to a decrease in overall economic development and growth in the country.
- Full Text:
- Date Issued: 2012
- Authors: Damane, Moeti
- Date: 2012
- Subjects: Rural-urban migration -- Employment -- Lesotho Informal sector (Economics) -- Lesotho Lesotho -- Economic conditions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1002 , http://hdl.handle.net/10962/d1002737
- Description: The research investigates the impact of internal rural - urban migration III Lesotho on household income and employment. Using data gathered from the 2002/03 household survey, the 2006 nationwide census and a questionnaire on rural - urban migration in Lesotho administered to 500 respondents in Maseru and Leribe, we estimate a logit model of the probability of employment in Lesotho in 2008 given a set of independent variables. The independent variables are respondent's work experience; years of education completed; employment status in 2004; employment status in 2008; gender; job skill level; place of residence in 2004 and a categorical variable that measures whether or not the respondent is a rural - urban migrant. The results suggest that migration and work experience have no significant impact on an individual's likelihood of being employed in the country's formal sector. Also, it was found that the higher the level of education an individual has, the less likely are their chances of employment in the country's formal sector because of the lack of formal jobs in the urban areas. Over 50% of Lesotho's workforce employed in the urban areas was discovered to work in the informal sector. The study concludes that there is a lack of jobs in Lesotho's urban formal sector that results in a thriving informal sector. The advantages of informal sector jobs to the rural - urban migrant include an increase in their standard of living as well as that of their family members left behind in the rural areas but the disadvantages include low levels of investor confidence that lead to a decrease in overall economic development and growth in the country.
- Full Text:
- Date Issued: 2012
Best practices to create an enabling environment for SME incubation in South Africa
- Authors: Dames, Ricardo Shane
- Date: 2012
- Subjects: Business incubators -- South Africa , New business enterprises -- South Africa , Small businesses -- South Africa -- Management
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:9301 , http://hdl.handle.net/10948/d1015031
- Description: The humble beginnings of business incubators date back to the 1970s in the USA and United Kingdom, where abandoned industrial buildings were converted to rent out to small businesses. South Africa (SA) was first introduced to business incubation in the 1980s when the Small Business Development Corporation (SBDC) established a number of business ‘hives’ and provided business space to entrepreneurs to operate their businesses. In their most basic form, business incubators provide a safe and nurturing environment for entrepreneurs to establish their small businesses. While in incubation, the Small and Medium Enterprises (SMEs) are supported with a number of services which assist their growth and development until they are able to exit the incubator as sustainable and viable businesses. Global incubator models have matured significantly, and now include assisting with business idea generation, accelerating business start-ups and commercialisation processes, and identifying high-growth orientated SMEs to assist them with gaining market access. The establishment of business incubators was a government-driven initiative, and more than 33 SME incubators exist in SA. Most of the incubators are government-funded, and have focused on the establishment and growth of SMEs to act as a catalyst to promote economic development and alleviate socio-economic challenges such as unemployment and poverty. Despite these noble objectives, incubation in SA has not been fully utilised, and a high SME failure rate still prevails in the country. One of the reasons for SME failure may be ascribed to the lack of an enabling SME incubation environment in SA. When compared to other developing countries such as Brazil with as many as 400 incubators, it is clear that the SA incubation industry still needs further development. The purpose of this study therefore was to ascertain the best practices of global business incubators in both developed and developing countries, and how SA incubators could learn from these best practices to create a more conducive and enabling SME incubation environment. Background literature on business incubation with a specific focus on best practices in world incubators in both developed and developing countries, was reviewed. Some of the literature reviewed included Aernoudt (2004), Buys and Mbewana (2007) and Chandra (2009). From the literature review, four main best practice areas were identified, namely strategic focus, sources of funding, incubator services, and the role of government. The study followed a qualitative approach, and an interview schedule was developed to seek the perceptions of incubator managers on how the four identified best practices can be utilised to create an enabling SA incubation environment. A survey was conducted by interviewing 14 incubator managers (twelve government and two private) in SA. Data was collected over a six-month period, using face-to-face and telephonic interviews. Data was analysed using the content analysis, constant comparison, grounded theory and case study methods. The biographical profiles of the incubator managers and incubators were presented in case studies. An initial analysis was made to identify themes and sub themes within the four best practices explored, using the constant comparison method. Thereafter a provincial comparative analysis was made, as well as a comparison of government funded versus privately funded incubators. The findings suggested that there is a relatively high turnover in incubator management, and that they often do not have incubator management experience. A provincial comparison of SA incubators revealed that their strategic focuses are greatly influenced by the industry prevailing in the various provinces. All SA incubators provide pre- and post incubation services, but few are utilising virtual incubation. Most SA incubators are government-funded, and some use a hybrid funding model. It was evident that most SA incubators are aware of government policies and programmes available to assist them on local, provincial and national levels. A comparison of the best practices of two developing countries and three developed countries, as well as suggestions made by SA incubator managers indicated that SA has indeed followed best practices from both developing and developed countries, but there are areas of non-alignment which provide scope for improvement, to create a more conducive and enabling incubation environment. This study recommends that incubators should have an entrepreneurial focus, and reposition and align their strategic focus with government policies and instruments. SA incubators must pursue opportunities for virtual incubation as well as linkages with academic institutions, in order to offer value-added services such as research, development and commercialisation of the product ideas. Incubators in SA must pursue a hybrid funding model with a combination of government and private funding, and generate some or their own income. With regard to the role of government, it is recommended that the roll-out of more industry-specific incubators be privatised, and that an overseeing body for incubation be established.
- Full Text:
- Date Issued: 2012
- Authors: Dames, Ricardo Shane
- Date: 2012
- Subjects: Business incubators -- South Africa , New business enterprises -- South Africa , Small businesses -- South Africa -- Management
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:9301 , http://hdl.handle.net/10948/d1015031
- Description: The humble beginnings of business incubators date back to the 1970s in the USA and United Kingdom, where abandoned industrial buildings were converted to rent out to small businesses. South Africa (SA) was first introduced to business incubation in the 1980s when the Small Business Development Corporation (SBDC) established a number of business ‘hives’ and provided business space to entrepreneurs to operate their businesses. In their most basic form, business incubators provide a safe and nurturing environment for entrepreneurs to establish their small businesses. While in incubation, the Small and Medium Enterprises (SMEs) are supported with a number of services which assist their growth and development until they are able to exit the incubator as sustainable and viable businesses. Global incubator models have matured significantly, and now include assisting with business idea generation, accelerating business start-ups and commercialisation processes, and identifying high-growth orientated SMEs to assist them with gaining market access. The establishment of business incubators was a government-driven initiative, and more than 33 SME incubators exist in SA. Most of the incubators are government-funded, and have focused on the establishment and growth of SMEs to act as a catalyst to promote economic development and alleviate socio-economic challenges such as unemployment and poverty. Despite these noble objectives, incubation in SA has not been fully utilised, and a high SME failure rate still prevails in the country. One of the reasons for SME failure may be ascribed to the lack of an enabling SME incubation environment in SA. When compared to other developing countries such as Brazil with as many as 400 incubators, it is clear that the SA incubation industry still needs further development. The purpose of this study therefore was to ascertain the best practices of global business incubators in both developed and developing countries, and how SA incubators could learn from these best practices to create a more conducive and enabling SME incubation environment. Background literature on business incubation with a specific focus on best practices in world incubators in both developed and developing countries, was reviewed. Some of the literature reviewed included Aernoudt (2004), Buys and Mbewana (2007) and Chandra (2009). From the literature review, four main best practice areas were identified, namely strategic focus, sources of funding, incubator services, and the role of government. The study followed a qualitative approach, and an interview schedule was developed to seek the perceptions of incubator managers on how the four identified best practices can be utilised to create an enabling SA incubation environment. A survey was conducted by interviewing 14 incubator managers (twelve government and two private) in SA. Data was collected over a six-month period, using face-to-face and telephonic interviews. Data was analysed using the content analysis, constant comparison, grounded theory and case study methods. The biographical profiles of the incubator managers and incubators were presented in case studies. An initial analysis was made to identify themes and sub themes within the four best practices explored, using the constant comparison method. Thereafter a provincial comparative analysis was made, as well as a comparison of government funded versus privately funded incubators. The findings suggested that there is a relatively high turnover in incubator management, and that they often do not have incubator management experience. A provincial comparison of SA incubators revealed that their strategic focuses are greatly influenced by the industry prevailing in the various provinces. All SA incubators provide pre- and post incubation services, but few are utilising virtual incubation. Most SA incubators are government-funded, and some use a hybrid funding model. It was evident that most SA incubators are aware of government policies and programmes available to assist them on local, provincial and national levels. A comparison of the best practices of two developing countries and three developed countries, as well as suggestions made by SA incubator managers indicated that SA has indeed followed best practices from both developing and developed countries, but there are areas of non-alignment which provide scope for improvement, to create a more conducive and enabling incubation environment. This study recommends that incubators should have an entrepreneurial focus, and reposition and align their strategic focus with government policies and instruments. SA incubators must pursue opportunities for virtual incubation as well as linkages with academic institutions, in order to offer value-added services such as research, development and commercialisation of the product ideas. Incubators in SA must pursue a hybrid funding model with a combination of government and private funding, and generate some or their own income. With regard to the role of government, it is recommended that the roll-out of more industry-specific incubators be privatised, and that an overseeing body for incubation be established.
- Full Text:
- Date Issued: 2012
Navigating the pathways to opening a new, effective community school : a case study in the Nelson Mandela Metropolitan Municipality of South Africa
- Authors: Damons, Bruce Peter
- Date: 2012
- Subjects: Community schools -- South Africa -- Port Elizabeth , Educational leadership -- South Africa -- Port Elizabeth , Teachers -- Recruiting -- South Africa -- Port Elizabeth , Teachers -- Training of -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9578 , http://hdl.handle.net/10948/d1019857
- Description: The provision of low cost housing has become one of the current South African government‟s top priorities. With the establishment of these new housing developments comes the need for accompanying social infrastructure. This includes the provisioning of schools, police stations, clinics and sports fields. In this study, I attempted to identify and explore the key basic elements that needed to be present when opening a new community school in one of these low income housing developments. The study gives voice to what key stakeholders thought these elements should be. The stakeholders were the teachers and community volunteers, which included parents of the learners. They actively participated in this study through the methodology of participatory action learning and action research (PALAR). The participants identified strong, compassionate and visionary leadership as an essential element that need to be present when opening up a new school. The study further shows that this leadership must have some knowledge of effective management systems in order to support the establishment of a new school. The findings also show that leadership and the effective implementation of these management systems rely heavily on the support of a variety of internal and external stakeholders, especially when support was lacking from the Department of Basic Education. The study further shows that the roles of the various stakeholders should be clearly defined and managed, so as to avoid tensions that might arise by having a large number of people involved in a confined space like a school. Teachers and community volunteers emerged as the key stakeholders who contributed to the effective functioning of the new school. Their continued involvement in the school requires on-going professional development and support.
- Full Text:
- Date Issued: 2012
- Authors: Damons, Bruce Peter
- Date: 2012
- Subjects: Community schools -- South Africa -- Port Elizabeth , Educational leadership -- South Africa -- Port Elizabeth , Teachers -- Recruiting -- South Africa -- Port Elizabeth , Teachers -- Training of -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9578 , http://hdl.handle.net/10948/d1019857
- Description: The provision of low cost housing has become one of the current South African government‟s top priorities. With the establishment of these new housing developments comes the need for accompanying social infrastructure. This includes the provisioning of schools, police stations, clinics and sports fields. In this study, I attempted to identify and explore the key basic elements that needed to be present when opening a new community school in one of these low income housing developments. The study gives voice to what key stakeholders thought these elements should be. The stakeholders were the teachers and community volunteers, which included parents of the learners. They actively participated in this study through the methodology of participatory action learning and action research (PALAR). The participants identified strong, compassionate and visionary leadership as an essential element that need to be present when opening up a new school. The study further shows that this leadership must have some knowledge of effective management systems in order to support the establishment of a new school. The findings also show that leadership and the effective implementation of these management systems rely heavily on the support of a variety of internal and external stakeholders, especially when support was lacking from the Department of Basic Education. The study further shows that the roles of the various stakeholders should be clearly defined and managed, so as to avoid tensions that might arise by having a large number of people involved in a confined space like a school. Teachers and community volunteers emerged as the key stakeholders who contributed to the effective functioning of the new school. Their continued involvement in the school requires on-going professional development and support.
- Full Text:
- Date Issued: 2012
The meaning of place of 'effective management' in the context of South African domestic tax law
- Authors: Daniels, Paul
- Date: 2012
- Subjects: Double taxation -- Treaties , Management
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8960 , http://hdl.handle.net/10948/d1018822
- Description: South Africa has a residence based system of taxation in which South African tax residents are taxed on their worldwide income. A company or other artificial person is regarded as a South African resident for tax purposes if it is incorporated, established or formed in South Africa or if its ‗effective management‘ is located in South Africa. Where a tax treaty determines in terms of its tie breaker rule that an artificial person is not resident in South Africa for treaty purposes, the company will also not be regarded as a tax resident in terms of South African domestic law. Treaties to which South Africa is party will often use the effective management‘ as the tie-breaker where a person other than an individual is resident in both Contracting states in terms of the respective states‘ domestic laws. The tests of ‗incorporation, established and formed‘ provide simplicity and certainty to governments but are easily open to manipulation by taxpayers. Therefore, the legislature found it necessary to incorporate effective management‘ as a test for residency into the Act. Effective management‘ is a substance over form concept which be described as a function which embodies the periodic, most senior executive management functions, which are required for the management of the affairs of the entity as whole. The test of effective management‘ by its very nature is concerned with where the crucial decisions are made in order to make a business function. To identify the location of effective management‘ it is necessary to enquire who calls the shots‘ in the context of the management of the company as opposed to who controls the company notwithstanding that there may in certain instances be overlap between the two functions. It is submitted that any person who, on the face of it seems unconnected to a company, could effectively manage‘ a company if that person is, in substance, responsible for the most senior executive management functions of the company. The discussion paper issued by SARS recognises the principal difficulties experienced with its current interpretation of the concept and makes valuable points, concessions and recommendations. It also recognised that the 'calling of shots' by the most senior executive is a critical marker of effective management‘ and that control of a company is irrelevant in determining effective management‘. To determine who effectively manages‘ a company each situation would have to be analysed on its own as it is not possible to create a definitive rule on the concept. In many cases the nature of the entity and its modus operandi would have to be taken into account to determine effective management.
- Full Text:
- Date Issued: 2012
- Authors: Daniels, Paul
- Date: 2012
- Subjects: Double taxation -- Treaties , Management
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8960 , http://hdl.handle.net/10948/d1018822
- Description: South Africa has a residence based system of taxation in which South African tax residents are taxed on their worldwide income. A company or other artificial person is regarded as a South African resident for tax purposes if it is incorporated, established or formed in South Africa or if its ‗effective management‘ is located in South Africa. Where a tax treaty determines in terms of its tie breaker rule that an artificial person is not resident in South Africa for treaty purposes, the company will also not be regarded as a tax resident in terms of South African domestic law. Treaties to which South Africa is party will often use the effective management‘ as the tie-breaker where a person other than an individual is resident in both Contracting states in terms of the respective states‘ domestic laws. The tests of ‗incorporation, established and formed‘ provide simplicity and certainty to governments but are easily open to manipulation by taxpayers. Therefore, the legislature found it necessary to incorporate effective management‘ as a test for residency into the Act. Effective management‘ is a substance over form concept which be described as a function which embodies the periodic, most senior executive management functions, which are required for the management of the affairs of the entity as whole. The test of effective management‘ by its very nature is concerned with where the crucial decisions are made in order to make a business function. To identify the location of effective management‘ it is necessary to enquire who calls the shots‘ in the context of the management of the company as opposed to who controls the company notwithstanding that there may in certain instances be overlap between the two functions. It is submitted that any person who, on the face of it seems unconnected to a company, could effectively manage‘ a company if that person is, in substance, responsible for the most senior executive management functions of the company. The discussion paper issued by SARS recognises the principal difficulties experienced with its current interpretation of the concept and makes valuable points, concessions and recommendations. It also recognised that the 'calling of shots' by the most senior executive is a critical marker of effective management‘ and that control of a company is irrelevant in determining effective management‘. To determine who effectively manages‘ a company each situation would have to be analysed on its own as it is not possible to create a definitive rule on the concept. In many cases the nature of the entity and its modus operandi would have to be taken into account to determine effective management.
- Full Text:
- Date Issued: 2012
Pre-concentration of toxic metals using electrospun amino-functionalized nylon-6 nanofibre sorbent
- Darko, G, Sobola, A, Adewuyi, Sheriff, Okonkwo, J O, Torto, N
- Authors: Darko, G , Sobola, A , Adewuyi, Sheriff , Okonkwo, J O , Torto, N
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6571 , http://hdl.handle.net/10962/d1004134
- Description: This paper presents a new approach for pre-concentrating toxic metals (As, Cd, Ni and Pb) in aqueous environments using an amino-functionalized electrospun nanofibre sorbent. The sorbent, composed of nanofibres of average diameter 80 ± 10 nm and specific surface area of 58m2 g–1, exhibited fast adsorption kinetics (<20 min) for As, Cd, Ni and Pb. The optimalpHfor the uptake of As, Cd, Ni and Pb were 5.5, 6.0, 6.5 and 11, respectively. The adsorption process best fitted the Freundlich isothermand followed the first-order kinetics. The highest pre-concentration achieved using the sorbent was 41.99 (Ni in treated wastewater). The capacity of the sorbent to pre-concentrate the toxic metals was compared with those of aqua regia and HNO3+H2O2 digestions. The pre-concentration factors achieved for Cd in river water samples can be ranked as aqua regia digestion (0.73) > adsorption (0.34)>HNO3+H2O2 (0.23) digestion.Asimilar trend was observed for Ni in river water as well as Ni andCdin tap water samples. Pb ions in the river water samples were pre-concentrated slightly better using the two digestion methods pre-concentration factors ~22) compared to adsorption method (pre-concentration factor ~21). The use of the electrospun amino-functionalized nanofibre sorbent presentsanefficientand cost-effective alternative for pre-concentration of toxic metals inaqueousenvironments.
- Full Text:
- Date Issued: 2012
- Authors: Darko, G , Sobola, A , Adewuyi, Sheriff , Okonkwo, J O , Torto, N
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6571 , http://hdl.handle.net/10962/d1004134
- Description: This paper presents a new approach for pre-concentrating toxic metals (As, Cd, Ni and Pb) in aqueous environments using an amino-functionalized electrospun nanofibre sorbent. The sorbent, composed of nanofibres of average diameter 80 ± 10 nm and specific surface area of 58m2 g–1, exhibited fast adsorption kinetics (<20 min) for As, Cd, Ni and Pb. The optimalpHfor the uptake of As, Cd, Ni and Pb were 5.5, 6.0, 6.5 and 11, respectively. The adsorption process best fitted the Freundlich isothermand followed the first-order kinetics. The highest pre-concentration achieved using the sorbent was 41.99 (Ni in treated wastewater). The capacity of the sorbent to pre-concentrate the toxic metals was compared with those of aqua regia and HNO3+H2O2 digestions. The pre-concentration factors achieved for Cd in river water samples can be ranked as aqua regia digestion (0.73) > adsorption (0.34)>HNO3+H2O2 (0.23) digestion.Asimilar trend was observed for Ni in river water as well as Ni andCdin tap water samples. Pb ions in the river water samples were pre-concentrated slightly better using the two digestion methods pre-concentration factors ~22) compared to adsorption method (pre-concentration factor ~21). The use of the electrospun amino-functionalized nanofibre sorbent presentsanefficientand cost-effective alternative for pre-concentration of toxic metals inaqueousenvironments.
- Full Text:
- Date Issued: 2012
Pre-concentration of heavy metals in aqueous environments using electrospun polymer nanofiber sorbents
- Authors: Darko, Godfred
- Date: 2012
- Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
- Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
- Full Text:
- Date Issued: 2012
- Authors: Darko, Godfred
- Date: 2012
- Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
- Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
- Full Text:
- Date Issued: 2012
The direct use value of municipal commonage goods and services to urban households in the Eastern Cape, South Africa
- Davenport, Nicholas A, Shackleton, Charlie M, Gambiza, James
- Authors: Davenport, Nicholas A , Shackleton, Charlie M , Gambiza, James
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181071 , vital:43696 , xlink:href="https://doi.org/10.1016/j.landusepol.2011.09.008"
- Description: To redress past racial discrepancies in ownership and tenure, the ANC government of South Africa initiated programmes to make land accessible to the previously disadvantaged. A key component of the national land reform programme was the provision of commonage lands to urban municipalities for use by the urban poor. However, there has been no assessment of the contribution that urban commonage makes to previously disadvantaged households. This study assessed the economic benefits of the commonage programme to local households, through an in-depth survey of 90 households across three small towns in the Eastern Cape of South Africa. We examined the marketed and non-marketed consumptive direct-use values of land-based livelihoods on commonage, calculated via the ‘own reported values’ approach. The results indicate that a proportion of South Africa's urban population rely to some degree on municipal commonage for part of their livelihoods. Commonage contributions to total livelihood incomes ranged between 14 and 20%. If the contributions from commonage were excluded, the incomes of over 10% of households in each study town would drop below the poverty line. Overall, the value of harvests from commonage was worth over R1 000 (US$ 142) per hectare per year and over R4.7 million (US$ 0.68 million) per commonage per year. However, the extent and nature of use and reliance was not uniform among households, so that we developed a typology of commonage users, with four types being identified. However, rapidly growing urban populations and high levels of poverty potentially threaten the sustainability of commonage resource use. Yet the national land reform programme focuses largely on the transfer of land to municipalities and not on sustainable management. Municipalities, in turn, invest relatively little in commonage management, and the little they do is focussed on livestock production. Non-timber forest products are not considered at all, even though this study shows that they are a vital resource for the urban poor, notably for energy and construction materials.
- Full Text:
- Date Issued: 2012
- Authors: Davenport, Nicholas A , Shackleton, Charlie M , Gambiza, James
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181071 , vital:43696 , xlink:href="https://doi.org/10.1016/j.landusepol.2011.09.008"
- Description: To redress past racial discrepancies in ownership and tenure, the ANC government of South Africa initiated programmes to make land accessible to the previously disadvantaged. A key component of the national land reform programme was the provision of commonage lands to urban municipalities for use by the urban poor. However, there has been no assessment of the contribution that urban commonage makes to previously disadvantaged households. This study assessed the economic benefits of the commonage programme to local households, through an in-depth survey of 90 households across three small towns in the Eastern Cape of South Africa. We examined the marketed and non-marketed consumptive direct-use values of land-based livelihoods on commonage, calculated via the ‘own reported values’ approach. The results indicate that a proportion of South Africa's urban population rely to some degree on municipal commonage for part of their livelihoods. Commonage contributions to total livelihood incomes ranged between 14 and 20%. If the contributions from commonage were excluded, the incomes of over 10% of households in each study town would drop below the poverty line. Overall, the value of harvests from commonage was worth over R1 000 (US$ 142) per hectare per year and over R4.7 million (US$ 0.68 million) per commonage per year. However, the extent and nature of use and reliance was not uniform among households, so that we developed a typology of commonage users, with four types being identified. However, rapidly growing urban populations and high levels of poverty potentially threaten the sustainability of commonage resource use. Yet the national land reform programme focuses largely on the transfer of land to municipalities and not on sustainable management. Municipalities, in turn, invest relatively little in commonage management, and the little they do is focussed on livestock production. Non-timber forest products are not considered at all, even though this study shows that they are a vital resource for the urban poor, notably for energy and construction materials.
- Full Text:
- Date Issued: 2012
Can sport impact rational investor behaviour? : an evaluation of the impact of national sporting performance on stock market returns in South Africa
- Authors: De Beer, Carl Francois
- Date: 2012
- Subjects: Investments -- Psychological aspects -- Research -- South Africa Finance -- Psychological aspects -- Research -- South Africa Sports -- Economic aspects -- Research -- South Africa Sports -- Psychological aspects -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:1013 , http://hdl.handle.net/10962/d1002748
- Description: The finance industry is an extremely fast and complex world dominated by the Efficient Markets Hypothesis (EMH). This theory contains many assumptions which include that investors are rational utility maximisers and that market prices reflect all relevant economic information available to the public. However, over the years, a new form of financial literature known as behavioural finance has been gaining momentum. Behavioural finance seeks to bridge the gap between psychology and economics in an attempt to gain a better understanding of how markets react to different situations. Behavioural finance has also gained much attention in recent years due to the EMH’s inability to explain many economic anomalies. This study first considers the differences between behavioural finance theory and EMH theory before explaining how an individual’s mood has the ability to influence one’s risk taking preferences. Mood changes were also found to be linked to changes in the way an individual reacts to different situations, the way they thinks and processes thoughts. Negative events were also found to have a greater influence on an individual’s mood than positive events did, resulting in an asymmetric relationship between positive and negative results. This study then examines numerous studies indicating how non-economic events can have a statistical and significant influence on stock market returns before analysing previous literature where sport was found to influence market prices. The aim of this study is to determine if South African national sporting performance can influence investors in such a way that it has the ability to impact on market returns. Using standard event study methodology, this study determines the constant mean return using the daily All-Share price index on the JSE for the period of 1 January 1990 to 31 December 2010. This study focuses on three of South Africa’s most popular sports, namely soccer, cricket and rugby and examine if these three sports have the ability to influence market returns. Although there is some evidence of a relationship between stock returns and sporting performance in the descriptive analysis, the regression results indicate that sporting performance in South Africa does not significantly explain abnormal market returns on the JSE. The study provides a number of possible reasons for this finding and concludes by suggesting areas for future research.
- Full Text:
- Date Issued: 2012
- Authors: De Beer, Carl Francois
- Date: 2012
- Subjects: Investments -- Psychological aspects -- Research -- South Africa Finance -- Psychological aspects -- Research -- South Africa Sports -- Economic aspects -- Research -- South Africa Sports -- Psychological aspects -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:1013 , http://hdl.handle.net/10962/d1002748
- Description: The finance industry is an extremely fast and complex world dominated by the Efficient Markets Hypothesis (EMH). This theory contains many assumptions which include that investors are rational utility maximisers and that market prices reflect all relevant economic information available to the public. However, over the years, a new form of financial literature known as behavioural finance has been gaining momentum. Behavioural finance seeks to bridge the gap between psychology and economics in an attempt to gain a better understanding of how markets react to different situations. Behavioural finance has also gained much attention in recent years due to the EMH’s inability to explain many economic anomalies. This study first considers the differences between behavioural finance theory and EMH theory before explaining how an individual’s mood has the ability to influence one’s risk taking preferences. Mood changes were also found to be linked to changes in the way an individual reacts to different situations, the way they thinks and processes thoughts. Negative events were also found to have a greater influence on an individual’s mood than positive events did, resulting in an asymmetric relationship between positive and negative results. This study then examines numerous studies indicating how non-economic events can have a statistical and significant influence on stock market returns before analysing previous literature where sport was found to influence market prices. The aim of this study is to determine if South African national sporting performance can influence investors in such a way that it has the ability to impact on market returns. Using standard event study methodology, this study determines the constant mean return using the daily All-Share price index on the JSE for the period of 1 January 1990 to 31 December 2010. This study focuses on three of South Africa’s most popular sports, namely soccer, cricket and rugby and examine if these three sports have the ability to influence market returns. Although there is some evidence of a relationship between stock returns and sporting performance in the descriptive analysis, the regression results indicate that sporting performance in South Africa does not significantly explain abnormal market returns on the JSE. The study provides a number of possible reasons for this finding and concludes by suggesting areas for future research.
- Full Text:
- Date Issued: 2012
An evaluation of urban poverty and its alleviation in the Nelson Mandela Metro with special reference to prostitution as an income generator
- Authors: De Bruin, Mbulelo Douglas
- Date: 2012
- Subjects: Economic conditions -- South Africa -- Nelson Mandela Metropolitan Municipality , Poverty -- South Africa -- Nelson Mandela Metropolitan Municipality , Prostitution -- South Africa -- Nelson Mandela Metropolitan Municipality
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9001 , http://hdl.handle.net/10948/d1011663 , Economic conditions -- South Africa -- Nelson Mandela Metropolitan Municipality , Poverty -- South Africa -- Nelson Mandela Metropolitan Municipality , Prostitution -- South Africa -- Nelson Mandela Metropolitan Municipality
- Description: This paper is set to evaluate the factors leading to prostitution and provide the understanding of the hardships that are experienced by prostitutes in their pursuit for income generation. However, this will be preceded by the background to the study. Secondly, this paper will lament or touch on the strategies employed by the Nelson Mandela Metro and other countries in an attempt to alleviate poverty. Thirdly, the views of academics and other experts in the fields of both the prostitution and poverty will be put into perspective. The relevant research methodology used to this study was found to be a descriptive study. The concluding remarks and recommendations on what is needed in order to improve the situation in the Nelson Mandela Metro are provided for the purpose of this study. Towards the end of this study, bibliography has been provided followed by the relevant annexures which will serve as evidence that inform this study.
- Full Text:
- Date Issued: 2012
- Authors: De Bruin, Mbulelo Douglas
- Date: 2012
- Subjects: Economic conditions -- South Africa -- Nelson Mandela Metropolitan Municipality , Poverty -- South Africa -- Nelson Mandela Metropolitan Municipality , Prostitution -- South Africa -- Nelson Mandela Metropolitan Municipality
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9001 , http://hdl.handle.net/10948/d1011663 , Economic conditions -- South Africa -- Nelson Mandela Metropolitan Municipality , Poverty -- South Africa -- Nelson Mandela Metropolitan Municipality , Prostitution -- South Africa -- Nelson Mandela Metropolitan Municipality
- Description: This paper is set to evaluate the factors leading to prostitution and provide the understanding of the hardships that are experienced by prostitutes in their pursuit for income generation. However, this will be preceded by the background to the study. Secondly, this paper will lament or touch on the strategies employed by the Nelson Mandela Metro and other countries in an attempt to alleviate poverty. Thirdly, the views of academics and other experts in the fields of both the prostitution and poverty will be put into perspective. The relevant research methodology used to this study was found to be a descriptive study. The concluding remarks and recommendations on what is needed in order to improve the situation in the Nelson Mandela Metro are provided for the purpose of this study. Towards the end of this study, bibliography has been provided followed by the relevant annexures which will serve as evidence that inform this study.
- Full Text:
- Date Issued: 2012
The effects of sustained attention, workload and task-related fatigue on physiological measures and performance during a tracking task
- Authors: De Gray Birch, Casey
- Date: 2012
- Subjects: Fatigue -- Physiological aspects -- Research , Attention -- Physiological aspects -- Research , Human engineering -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5120 , http://hdl.handle.net/10962/d1005198 , Fatigue -- Physiological aspects -- Research , Attention -- Physiological aspects -- Research , Human engineering -- Research
- Description: Despite extensive research into the concept of mental fatigue there is as yet no “gold standard” definition or measurement technique available. Because of this a large amount of fatigue-related errors are still seen in the workplace. The complexity of the problem lies with the inability to directly measure mental processes as well as the various endogenous and exogenous factors that interact to produce the experienced fatigue. Fatigue has been divided into sleep-related and task-related fatigue; however the task-related aspect is evident both during normal waking hours as well as during periods of sleep deprivation, therefore this aspect is considered important in the understanding of fatigue in general. The concept of task-related fatigue has further been divided into active and passive fatigue states; however differentiation between the two requires careful consideration. Various physiological measures have been employed in an attempt to gain a better understanding of the mechanisms involved in the generation of fatigue, however often studies have produced dissociating results. The current study considered the task-related fatigue elicited by a tracking task requiring sustained attention, in order to evaluate the usefulness of various cardiovascular and oculomotor measures as indicators of fatigue. A secondary aim was to determine whether the behavioural and physiological parameter responses could be used to infer the type of fatigue incurred (i.e. an active versus passive fatigue state) as well as the energetical mechanisms involved during task performance. A simple driving simulator task was used as the main tracking task, requiring constant attention and concentration. This task was performed for approximately two hours. Three experimental groups (consisting of 14 subjects each) were used: a control group that performed the tracking task only, a group that performed a five minute auditory memory span task concurrently with the driving task after every 20 minutes of pure driving, and a group that performed a visual choice reaction task for five minutes following every 20 minute driving period. The secondary tasks were employed in order to evaluate the extent of resource allocation as well as arousal level. Performance measures included various driving performance parameters, as well as secondary task performance. Physiological measures included heart rate frequency (HR) and various time- and frequency-domain heart rate variability (HRV)parameters, pupil dilation, blink frequency and duration, fixations, and saccadic parameters as well as critical flicker fusion frequency (CFFF). The Borg CR-10 scale was used to evaluate subjective fatigue during the task, and the NASA-TLX was completed following the task. A decline in driving performance over time was supplemented by measures such as HR, HRV and pupil dilation indicating an increase in parasympathetic activity (or a reduction in arousal). An increase in blink frequency was considered as a sign of withdrawal of attentional resources over time. Longer and faster saccades were also evident over time, coupled with shorter fixations. With regards to the secondary task influence, the choice RT task did not affect any behavioural or physiological parameters, thereby contesting the active fatigue theory of resource depletion, as well as implying that the increase in demand for the same resources used by the primary task was insufficient to affect the state of the subjects. The increased load elicited by the memory span task improved driving performance and increased measures of HR, HRV, pupil dilation and blink frequency. Some of these measures produced opposite effects to what was expected; an attempt to explain the dissociation of the various physiological parameters was expressed in terms of arousal, effort and resource theories. Overall, the results indicate that the fatigue and/or reduced arousal accompanying a monotonous sustained attention task can, to some degree, be alleviated through intermittent performance of a secondary task engaging mental resources other than the ones used for the primary task. The degree to which such a task is beneficial, however, requires careful consideration as while an immediate increase in arousal and primary task performance is noted, the impact of the task on general attentional resources may be detrimental in the case of reacting should an emergency situation occur.
- Full Text:
- Date Issued: 2012
- Authors: De Gray Birch, Casey
- Date: 2012
- Subjects: Fatigue -- Physiological aspects -- Research , Attention -- Physiological aspects -- Research , Human engineering -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5120 , http://hdl.handle.net/10962/d1005198 , Fatigue -- Physiological aspects -- Research , Attention -- Physiological aspects -- Research , Human engineering -- Research
- Description: Despite extensive research into the concept of mental fatigue there is as yet no “gold standard” definition or measurement technique available. Because of this a large amount of fatigue-related errors are still seen in the workplace. The complexity of the problem lies with the inability to directly measure mental processes as well as the various endogenous and exogenous factors that interact to produce the experienced fatigue. Fatigue has been divided into sleep-related and task-related fatigue; however the task-related aspect is evident both during normal waking hours as well as during periods of sleep deprivation, therefore this aspect is considered important in the understanding of fatigue in general. The concept of task-related fatigue has further been divided into active and passive fatigue states; however differentiation between the two requires careful consideration. Various physiological measures have been employed in an attempt to gain a better understanding of the mechanisms involved in the generation of fatigue, however often studies have produced dissociating results. The current study considered the task-related fatigue elicited by a tracking task requiring sustained attention, in order to evaluate the usefulness of various cardiovascular and oculomotor measures as indicators of fatigue. A secondary aim was to determine whether the behavioural and physiological parameter responses could be used to infer the type of fatigue incurred (i.e. an active versus passive fatigue state) as well as the energetical mechanisms involved during task performance. A simple driving simulator task was used as the main tracking task, requiring constant attention and concentration. This task was performed for approximately two hours. Three experimental groups (consisting of 14 subjects each) were used: a control group that performed the tracking task only, a group that performed a five minute auditory memory span task concurrently with the driving task after every 20 minutes of pure driving, and a group that performed a visual choice reaction task for five minutes following every 20 minute driving period. The secondary tasks were employed in order to evaluate the extent of resource allocation as well as arousal level. Performance measures included various driving performance parameters, as well as secondary task performance. Physiological measures included heart rate frequency (HR) and various time- and frequency-domain heart rate variability (HRV)parameters, pupil dilation, blink frequency and duration, fixations, and saccadic parameters as well as critical flicker fusion frequency (CFFF). The Borg CR-10 scale was used to evaluate subjective fatigue during the task, and the NASA-TLX was completed following the task. A decline in driving performance over time was supplemented by measures such as HR, HRV and pupil dilation indicating an increase in parasympathetic activity (or a reduction in arousal). An increase in blink frequency was considered as a sign of withdrawal of attentional resources over time. Longer and faster saccades were also evident over time, coupled with shorter fixations. With regards to the secondary task influence, the choice RT task did not affect any behavioural or physiological parameters, thereby contesting the active fatigue theory of resource depletion, as well as implying that the increase in demand for the same resources used by the primary task was insufficient to affect the state of the subjects. The increased load elicited by the memory span task improved driving performance and increased measures of HR, HRV, pupil dilation and blink frequency. Some of these measures produced opposite effects to what was expected; an attempt to explain the dissociation of the various physiological parameters was expressed in terms of arousal, effort and resource theories. Overall, the results indicate that the fatigue and/or reduced arousal accompanying a monotonous sustained attention task can, to some degree, be alleviated through intermittent performance of a secondary task engaging mental resources other than the ones used for the primary task. The degree to which such a task is beneficial, however, requires careful consideration as while an immediate increase in arousal and primary task performance is noted, the impact of the task on general attentional resources may be detrimental in the case of reacting should an emergency situation occur.
- Full Text:
- Date Issued: 2012
Identification of novel marine algal compounds with differential anti-cancer activity: towards a cancer stem-cell specific chemotherapy
- Authors: De la Mare, Jo-Anne
- Date: 2012
- Subjects: Breast -- Cancer , Stem cells -- Research , Chemotherapy , Algae -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4143 , http://hdl.handle.net/10962/d1016250
- Description: Breast cancer remains the leading cause of cancer-related death in women worldwide. Furthermore, it has been demonstrated that the treatment-resistant ER-PR-HER2/neu- sub-type is more common among women of African descent, necessitating the search for novel chemotherapies for this form of the disease. The secondary metabolites produced by marine algae represent a rich source of structurally unique compounds with chemotherapeutic potential, particularly in South Africa, whose oceans allegedly host 15 % of the total number of species in the world. Indeed, a recent study reported the isolation of a range of novel compounds from South African red and brown algae of the Plocamium, Portiera and Sargassum genera which displayed cytotoxicity against oesophageal cancer cells in vitro. The molecular mechanisms mediating this toxicity were unknown, as was the effect of these and similar compounds on metastatic ER-PR-HER2/neu- breast cancer cell lines or breast cancer stem cells. The current study aimed to address these questions by screening a library of twenty-two novel marine algal compounds for the ability to inhibit MDA-MB-231 and Hs578T breast cancer cells, while having no adverse effects on non-cancerous MCF12A breast epithelial cells. While twelve of these were toxic in the micromolar range against breast cancer cells, only the polyhalogenated monoterpenes RU004 and RU007, and the tetraprenylated quinone sargaquinoic acid (SQA) were identified as hit compounds based on the criteria that their cytotoxicity was specific to breast cancer and not healthy breast cells in vitro. On the other hand, the halogenated monoterpene RU015 was found to be highly toxic to both breast cancer and non-cancerous breast cell lines, while the halogenated monoterpene stereoisomers RU017 and RU018 were non-toxic to either of these cell lines. The mode of action of RU004, RU007, RU015 and SQA, together with the previously characterized carotenoid fucoxanthin (FXN), was assessed in terms of the type of cell death induced and the effect on cell cycle distribution of these compounds. Flow cytometric analysis of the extent of Hoescht 33342 and propidium iodide staining along with PARP cleavage studies suggested that SQA induced apoptosis in MDA-MB-231 cells. On the other hand, the highly toxic compound RU015 appeared to induce necrosis as evidenced by 50 kDa PARP cleavage product in MDA-MB-231 cells. The flow cytometry profiles of MDA-MB-231 and Hst578T cells treated with the hit compounds RU004 and RU007 were suggestive of the induction of apoptosis by these compounds. Cell cycle analysis by flow cytometry with propidium iodide staining revealed that both SQA and FXN induced G0-G1 arrest together with an increase in the apoptotic sub-G0 population, which agreed with previous reports in the literature. The molecular mechanism of action of SQA and FXN were further investigated by the identification of specific signal transducer molecules involved in mediating their anti-cancer activities. SQA was found to require the activity of numerous caspases, including caspase-3, -6, -8, -9, -10 and -13, for its cytotoxicity and was demonstrated to decrease the level of the antiapoptotic protein Bcl-2. On the other hand, FXN was shown to require caspase-1, -2, -3, -9 and - 10 for its toxicity. This, together with the ability to decrease the levels of Bcl-2, pointed to the involvement of the intrinsic pathway in particular in mediating the activity of FXN. The screening of algal compounds against non-cancerous breast epithelial cells carried out in this study, together with the investigation into their mechanisms of action, represent one of the few reports in which characterization of algal metabolites goes beyond the initial cytotoxicity assays. Finally, in order to assess the potential anti-cancer stem cell activity of the marine algal compounds, a subset of these was screened using a mammosphere assay technique developed in this study. The cancer stem cell (CSC) theory proposes that cancers arise from and are maintained by a specific subpopulation of cells able to undergo asymmetric cell division and termed CSCs. These CSCs are capable of anchorage-independent growth in serum-free culture conditions, such as those in the mammosphere assay. Using this assay, the novel halogenated monoterpene stereoisomers RU017 and RU018 were demonstrated to possess putative anti- CSC activity as evidenced by their ability to completely eliminate mammosphere formation in vitro. Furthermore, since RU017 and RU018 were non-toxic to both breast cancer and healthy breast cells, it appeared that the activity of the compounds was potentially specific to the CSCs. The results require further validation, but represent the first report of selective anti-CSC activity.
- Full Text:
- Date Issued: 2012
- Authors: De la Mare, Jo-Anne
- Date: 2012
- Subjects: Breast -- Cancer , Stem cells -- Research , Chemotherapy , Algae -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4143 , http://hdl.handle.net/10962/d1016250
- Description: Breast cancer remains the leading cause of cancer-related death in women worldwide. Furthermore, it has been demonstrated that the treatment-resistant ER-PR-HER2/neu- sub-type is more common among women of African descent, necessitating the search for novel chemotherapies for this form of the disease. The secondary metabolites produced by marine algae represent a rich source of structurally unique compounds with chemotherapeutic potential, particularly in South Africa, whose oceans allegedly host 15 % of the total number of species in the world. Indeed, a recent study reported the isolation of a range of novel compounds from South African red and brown algae of the Plocamium, Portiera and Sargassum genera which displayed cytotoxicity against oesophageal cancer cells in vitro. The molecular mechanisms mediating this toxicity were unknown, as was the effect of these and similar compounds on metastatic ER-PR-HER2/neu- breast cancer cell lines or breast cancer stem cells. The current study aimed to address these questions by screening a library of twenty-two novel marine algal compounds for the ability to inhibit MDA-MB-231 and Hs578T breast cancer cells, while having no adverse effects on non-cancerous MCF12A breast epithelial cells. While twelve of these were toxic in the micromolar range against breast cancer cells, only the polyhalogenated monoterpenes RU004 and RU007, and the tetraprenylated quinone sargaquinoic acid (SQA) were identified as hit compounds based on the criteria that their cytotoxicity was specific to breast cancer and not healthy breast cells in vitro. On the other hand, the halogenated monoterpene RU015 was found to be highly toxic to both breast cancer and non-cancerous breast cell lines, while the halogenated monoterpene stereoisomers RU017 and RU018 were non-toxic to either of these cell lines. The mode of action of RU004, RU007, RU015 and SQA, together with the previously characterized carotenoid fucoxanthin (FXN), was assessed in terms of the type of cell death induced and the effect on cell cycle distribution of these compounds. Flow cytometric analysis of the extent of Hoescht 33342 and propidium iodide staining along with PARP cleavage studies suggested that SQA induced apoptosis in MDA-MB-231 cells. On the other hand, the highly toxic compound RU015 appeared to induce necrosis as evidenced by 50 kDa PARP cleavage product in MDA-MB-231 cells. The flow cytometry profiles of MDA-MB-231 and Hst578T cells treated with the hit compounds RU004 and RU007 were suggestive of the induction of apoptosis by these compounds. Cell cycle analysis by flow cytometry with propidium iodide staining revealed that both SQA and FXN induced G0-G1 arrest together with an increase in the apoptotic sub-G0 population, which agreed with previous reports in the literature. The molecular mechanism of action of SQA and FXN were further investigated by the identification of specific signal transducer molecules involved in mediating their anti-cancer activities. SQA was found to require the activity of numerous caspases, including caspase-3, -6, -8, -9, -10 and -13, for its cytotoxicity and was demonstrated to decrease the level of the antiapoptotic protein Bcl-2. On the other hand, FXN was shown to require caspase-1, -2, -3, -9 and - 10 for its toxicity. This, together with the ability to decrease the levels of Bcl-2, pointed to the involvement of the intrinsic pathway in particular in mediating the activity of FXN. The screening of algal compounds against non-cancerous breast epithelial cells carried out in this study, together with the investigation into their mechanisms of action, represent one of the few reports in which characterization of algal metabolites goes beyond the initial cytotoxicity assays. Finally, in order to assess the potential anti-cancer stem cell activity of the marine algal compounds, a subset of these was screened using a mammosphere assay technique developed in this study. The cancer stem cell (CSC) theory proposes that cancers arise from and are maintained by a specific subpopulation of cells able to undergo asymmetric cell division and termed CSCs. These CSCs are capable of anchorage-independent growth in serum-free culture conditions, such as those in the mammosphere assay. Using this assay, the novel halogenated monoterpene stereoisomers RU017 and RU018 were demonstrated to possess putative anti- CSC activity as evidenced by their ability to completely eliminate mammosphere formation in vitro. Furthermore, since RU017 and RU018 were non-toxic to both breast cancer and healthy breast cells, it appeared that the activity of the compounds was potentially specific to the CSCs. The results require further validation, but represent the first report of selective anti-CSC activity.
- Full Text:
- Date Issued: 2012
Quinones and halogenated monoterpenes of algal origin show anti-proliferative effects against breast cancer cells in vitro:
- de la Mare, Jo-Anne, Lawson, Jessica C, Chiwakata, Maynard T, Beukes, Denzil R, Blatch, Gregory L, Edkins, Adrienne L
- Authors: de la Mare, Jo-Anne , Lawson, Jessica C , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165165 , vital:41214 , DOI: 10.1007/s10637-011-9788-0
- Description: Red and brown algae have been shown to produce a variety of compounds with chemotherapeutic potential. A recent report described the isolation of a range of novel polyhalogenated monoterpene compounds from the red algae Plocamium corallorhiza and Plocamium cornutum collected off the coast of South Africa, together with the previously described tetraprenylquinone, sargaquinoic acid (SQA), from the brown algae Sargassum heterophyllum. In our study, the algal compounds were screened for anti-proliferative activity against metastatic MDA-MB-231 breast cancer cells revealing that a number of compounds displayed anti-cancer activity with IC50 values in the micromolar range. A subset of the compounds was tested for differential toxicity in the MCF-7/MCF12A system and five of these, including sargaquinoic acid, were found to be at least three times more toxic to the breast cancer than the non-malignant cell line.
- Full Text:
- Date Issued: 2012
- Authors: de la Mare, Jo-Anne , Lawson, Jessica C , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165165 , vital:41214 , DOI: 10.1007/s10637-011-9788-0
- Description: Red and brown algae have been shown to produce a variety of compounds with chemotherapeutic potential. A recent report described the isolation of a range of novel polyhalogenated monoterpene compounds from the red algae Plocamium corallorhiza and Plocamium cornutum collected off the coast of South Africa, together with the previously described tetraprenylquinone, sargaquinoic acid (SQA), from the brown algae Sargassum heterophyllum. In our study, the algal compounds were screened for anti-proliferative activity against metastatic MDA-MB-231 breast cancer cells revealing that a number of compounds displayed anti-cancer activity with IC50 values in the micromolar range. A subset of the compounds was tested for differential toxicity in the MCF-7/MCF12A system and five of these, including sargaquinoic acid, were found to be at least three times more toxic to the breast cancer than the non-malignant cell line.
- Full Text:
- Date Issued: 2012
Guidelines to establish an e-safety awareness in South Africa
- Authors: De Lange, Mariska
- Date: 2012
- Subjects: Internet and children--Safety measures , Internet in education , Online etiquette
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9747 , http://hdl.handle.net/10948/d1007863 , Internet and children--Safety measures , Internet in education , Online etiquette
- Description: Information and Communication Technology (ICT) has become an integral part of almost every individual’s life. Although ICT, particularly the Internet, might offer numerous opportunities, individuals should also be aware of the associated risks. Especially with the younger generations who can be seen as being the most vulnerable to online dangers as they are becoming more involved in online activities. Children are utilizing new technologies from an early age and should know how to keep themselves and others safe whilst accessing the Internet. However, most of them do not have the required knowledge and expertise to protect themselves. This is because, under most circumstances, the parents do not understand their children’s online behaviours and activities and are, therefore, unable to teach their children how to utilize it safe and responsibly. A school can be seen as the perfect place to teach children safe online behaviours. However, there is currently a definite lack of e-Safety in South African schools, because no e-Safety policies are in place and there is little or nothing in curricula with regards to e-Safety. This can lead to additional concerns. The primary objective of this research study is, therefore, to develop, motivate and verify a framework that might contribute towards the development of an e-Safety culture. This e-Safety culture should allow individuals to adapt their behavior towards the secure utilization of ICT. However, for the purpose of this research study, the focus will primarily be on learners from primary and secondary schools.
- Full Text:
- Date Issued: 2012
- Authors: De Lange, Mariska
- Date: 2012
- Subjects: Internet and children--Safety measures , Internet in education , Online etiquette
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9747 , http://hdl.handle.net/10948/d1007863 , Internet and children--Safety measures , Internet in education , Online etiquette
- Description: Information and Communication Technology (ICT) has become an integral part of almost every individual’s life. Although ICT, particularly the Internet, might offer numerous opportunities, individuals should also be aware of the associated risks. Especially with the younger generations who can be seen as being the most vulnerable to online dangers as they are becoming more involved in online activities. Children are utilizing new technologies from an early age and should know how to keep themselves and others safe whilst accessing the Internet. However, most of them do not have the required knowledge and expertise to protect themselves. This is because, under most circumstances, the parents do not understand their children’s online behaviours and activities and are, therefore, unable to teach their children how to utilize it safe and responsibly. A school can be seen as the perfect place to teach children safe online behaviours. However, there is currently a definite lack of e-Safety in South African schools, because no e-Safety policies are in place and there is little or nothing in curricula with regards to e-Safety. This can lead to additional concerns. The primary objective of this research study is, therefore, to develop, motivate and verify a framework that might contribute towards the development of an e-Safety culture. This e-Safety culture should allow individuals to adapt their behavior towards the secure utilization of ICT. However, for the purpose of this research study, the focus will primarily be on learners from primary and secondary schools.
- Full Text:
- Date Issued: 2012
The biota of the Swartkops Solar Saltworks and their potential for producing biofuels
- Authors: De Lauwere, Monique Simone
- Date: 2012
- Subjects: Organisms , Biomass energy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10625 , http://hdl.handle.net/10948/d1011657 , Organisms , Biomass energy
- Description: The Swartkops and Missionvale salinas in Port Elizabeth on the east coast of South Africa are surrounding by large informal settlements. The runoff from these settlements contributes largely to the eutrophication of the solar saltworks which in turn has an effect on the biotic functioning of the systems, ultimately affecting the quantity and quality of the salt produced. Inorganic nutrients and organic composition, as well as important biological groups were examined within the brine with the aim of comparing the current condition of the same salinas to their condition twelve years ago. Comparisons between inorganic nutrient concentrations and biological groups showed significantly higher inorganic nutrients, with chlorophyll a concentrations in the Swartkops salina in 2011 being significantly higher than in 2012 and the 1999 and 2011 chlorophyll a concentrations being significantly higher than 2012 in the Missionvale salina. Microalgae found in the salinas were cultured in four different growth media. Cells were stained with Nile Red fluorescent dye in order to estimate the extent of lipids production. Five of the most promising lipid producing species were isolated into a monoculture and grown at different salinities to establish the growth and lipid production in response to salinity. Halamphora coffeaeformis and Navicula sp. were found to be the best candidate species. They grew best at salinities between 50 and 70 psu and produced lipid vesicles consuming approximately 10 percent of the cell.
- Full Text:
- Date Issued: 2012
- Authors: De Lauwere, Monique Simone
- Date: 2012
- Subjects: Organisms , Biomass energy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10625 , http://hdl.handle.net/10948/d1011657 , Organisms , Biomass energy
- Description: The Swartkops and Missionvale salinas in Port Elizabeth on the east coast of South Africa are surrounding by large informal settlements. The runoff from these settlements contributes largely to the eutrophication of the solar saltworks which in turn has an effect on the biotic functioning of the systems, ultimately affecting the quantity and quality of the salt produced. Inorganic nutrients and organic composition, as well as important biological groups were examined within the brine with the aim of comparing the current condition of the same salinas to their condition twelve years ago. Comparisons between inorganic nutrient concentrations and biological groups showed significantly higher inorganic nutrients, with chlorophyll a concentrations in the Swartkops salina in 2011 being significantly higher than in 2012 and the 1999 and 2011 chlorophyll a concentrations being significantly higher than 2012 in the Missionvale salina. Microalgae found in the salinas were cultured in four different growth media. Cells were stained with Nile Red fluorescent dye in order to estimate the extent of lipids production. Five of the most promising lipid producing species were isolated into a monoculture and grown at different salinities to establish the growth and lipid production in response to salinity. Halamphora coffeaeformis and Navicula sp. were found to be the best candidate species. They grew best at salinities between 50 and 70 psu and produced lipid vesicles consuming approximately 10 percent of the cell.
- Full Text:
- Date Issued: 2012
Cultural interpretations of traumatic events and post traumatic stress disorder (PTSD) symptoms of IsiXhosa-speaking adults
- Authors: De Villiers, Derika
- Date: 2012
- Subjects: Post-traumatic stress disorder , Emotions and cognition , Psychic trauma
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9878 , http://hdl.handle.net/10948/d1008379 , Post-traumatic stress disorder , Emotions and cognition , Psychic trauma
- Description: South Africa as a country is known for its high crime rate which produces an ongoing traumatising environment for its multicultural nation. Posttraumatic stress disorder in the general South African population is thought to be more prevalent than most international norms which make this topic both relevant and important. Cultural diversity is seen to play a role in the experience of PTSD which means that it has become important to gain an understanding of the potential effect of the individual’s cultural background on the processing of a traumatic experience and the symptoms related to the experience. The proposed research focused on appraisals of the traumatic event and symptoms (in schematic and cultural terms). An interpretive (with current cognitive conceptions of the disorder as guiding theory) phenomenological approach was used. The sample consisted of eight isiXhosa-speaking adults that qualified for a diagnosis of PTSD with no prior psychiatric diagnosis. Data was gathered using a semi-structured interview and analysed using the Interpretive Phenomenological Analysis. Results indicated that participants understood their PTSD symptoms in a functional manner but struggled to make sense of their traumatic event. Not understanding their traumatic event was the variable that maintained their PTSD diagnosis. Most of the interpretations made by these participants were fairly universal and there were very few links to content that can directly be attributed to a traditional African worldview. Practitioners may not need to completely reinvent the wheel as far as treatment strategies for PTSD for isiXhosa-speaking individuals in an urban setting go.
- Full Text:
- Date Issued: 2012
- Authors: De Villiers, Derika
- Date: 2012
- Subjects: Post-traumatic stress disorder , Emotions and cognition , Psychic trauma
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9878 , http://hdl.handle.net/10948/d1008379 , Post-traumatic stress disorder , Emotions and cognition , Psychic trauma
- Description: South Africa as a country is known for its high crime rate which produces an ongoing traumatising environment for its multicultural nation. Posttraumatic stress disorder in the general South African population is thought to be more prevalent than most international norms which make this topic both relevant and important. Cultural diversity is seen to play a role in the experience of PTSD which means that it has become important to gain an understanding of the potential effect of the individual’s cultural background on the processing of a traumatic experience and the symptoms related to the experience. The proposed research focused on appraisals of the traumatic event and symptoms (in schematic and cultural terms). An interpretive (with current cognitive conceptions of the disorder as guiding theory) phenomenological approach was used. The sample consisted of eight isiXhosa-speaking adults that qualified for a diagnosis of PTSD with no prior psychiatric diagnosis. Data was gathered using a semi-structured interview and analysed using the Interpretive Phenomenological Analysis. Results indicated that participants understood their PTSD symptoms in a functional manner but struggled to make sense of their traumatic event. Not understanding their traumatic event was the variable that maintained their PTSD diagnosis. Most of the interpretations made by these participants were fairly universal and there were very few links to content that can directly be attributed to a traditional African worldview. Practitioners may not need to completely reinvent the wheel as far as treatment strategies for PTSD for isiXhosa-speaking individuals in an urban setting go.
- Full Text:
- Date Issued: 2012
Factors affecting survivorship of loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles of South Africa
- Authors: De Wet, Anje
- Date: 2012
- Subjects: Loggerhead turtle -- South Africa , Leatherback turtle -- South Africa , Sea turtles -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10686 , http://hdl.handle.net/10948/d1007900 , Loggerhead turtle -- South Africa , Leatherback turtle -- South Africa , Sea turtles -- South Africa
- Description: Loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles as well as their eggs and hatchlings have been protected on their nesting beach in South Africa (SA) since 1963. Both nesting populations were expected to show similar trends in recovery following the application of identical protection and conservation measures. The loggerhead nesting population has responded favourably to these protection efforts. In contrast, the leatherback nesting population showed an initial increase but is currently stable. The reason for this difference in response is thought to be due to differential offshore mortality of these two species. This prompted an investigation into the different sources of sea turtle mortality in the South Western Indian Ocean (SWIO). Specific aims were to identify and quantify sources of loggerhead and leatherback mortality on nesting beaches as well as in the oceans. Reasonable survivorship at all age classes is important to ensure recruitment of new nesting individuals into sea turtle populations. Mortality of nests, eggs per nest and hatchlings were quantified over two seasons for the loggerheads and leatherbacks nesting in SA. The beach was patrolled on foot to encounter and record females emerging from the ocean and later, hatchlings from their nests. The nests were then monitored during the incubation period and excavated once hatched. The fates of 925 nests were determined during these two nesting seasons (2009/2010 and 2010/2011). The main source of loggerhead and leatherback nest destruction was predation (8.6 percent and 15.7 percent respectively) followed by nest erosion (2.2 percent and 6.3 percent respectively). Overall nest success was high but higher for loggerheads (89 percent) than for leatherbacks (78 percent). The main cause of egg mortality for both species was early developmental arrest, followed by predation by ants and ghost crabs. Hatchlings en route to the sea were almost exclusively predated by ghost crabs (4.2 percent of emerged loggerhead hatchlings and 3.2 percent of emerged leatherback hatchlings). It appears that both species benefit from the coastal conservation efforts. When sea turtles leave the nesting beach, either as hatchlings or adults, conservation and monitoring becomes more difficult and sea turtles are exposed to a multitude of threats, including anthropogenic threats. Age classes tend to be spatially separated due to different habitat and dietary requirements. The type of threat sea turtles are exposed to thus depends on the current age class. Offshore sources of mortality in the SWIO were identified and where possible loggerhead and leatherback mortality was quantified and mapped spatially. Loggerheads were mostly exposed to and had the highest mortality in the artisanal fisheries in the SWIO (> 1000 per annum), inshore trawling (ca. 41 per annum), shark nets (protective gill nets) (21.6 ± 6.7 per annum) and the pelagic longline fishery (5.0 ± 4.4 per annum). In contrast, leatherbacks with a pelagic lifestyle, were mostly exposed to pelagic longline fisheries (7.8 ± 7.8 per annum). A spatial analysis of fishing activities indicated that leatherback home ranges overlapped 41percent with pelagic longline fishing activity in the SA EEZ, whereas the overlap between pelagic longliners and loggerhead home ranges was 29 percent. The quantified sources of mortality provide some explanation for the trend in the loggerhead nesting population but not the trend in the leatherback nesting population. Hatchling survivorship to adulthood was estimated to determine the viability of the two nesting populations as well as to determine whether offshore mortality was responsible for the difference in recovery of the two populations. Loggerhead hatchling survivorship to adulthood was estimated at between 2 and 10 per 1000 hatchlings, the minimum requirement for an increasing population. The adopted sophisticated model shows that leatherbacks have a survival rate of 5 to 10 per 1 000 hatchlings. However, this suggests that the population is increasing, but the leatherback population is stable. Perhaps the age to maturity of SA leatherbacks is greater than 12 years, or fisheries-related mortality affects younger age classes than initially thought. It is therefore recommended that the turtle monitoring area is extended to include other potential nesting grounds. In addition, observer or monitoring programs for commercial as well as artisanal fisheries needs to be extended throughout the SWIO to quantify sea turtle mortality. Ultimately a comprehensive multi-regional approach is required for the conservation of these highly migratory species.
- Full Text:
- Date Issued: 2012
- Authors: De Wet, Anje
- Date: 2012
- Subjects: Loggerhead turtle -- South Africa , Leatherback turtle -- South Africa , Sea turtles -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10686 , http://hdl.handle.net/10948/d1007900 , Loggerhead turtle -- South Africa , Leatherback turtle -- South Africa , Sea turtles -- South Africa
- Description: Loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles as well as their eggs and hatchlings have been protected on their nesting beach in South Africa (SA) since 1963. Both nesting populations were expected to show similar trends in recovery following the application of identical protection and conservation measures. The loggerhead nesting population has responded favourably to these protection efforts. In contrast, the leatherback nesting population showed an initial increase but is currently stable. The reason for this difference in response is thought to be due to differential offshore mortality of these two species. This prompted an investigation into the different sources of sea turtle mortality in the South Western Indian Ocean (SWIO). Specific aims were to identify and quantify sources of loggerhead and leatherback mortality on nesting beaches as well as in the oceans. Reasonable survivorship at all age classes is important to ensure recruitment of new nesting individuals into sea turtle populations. Mortality of nests, eggs per nest and hatchlings were quantified over two seasons for the loggerheads and leatherbacks nesting in SA. The beach was patrolled on foot to encounter and record females emerging from the ocean and later, hatchlings from their nests. The nests were then monitored during the incubation period and excavated once hatched. The fates of 925 nests were determined during these two nesting seasons (2009/2010 and 2010/2011). The main source of loggerhead and leatherback nest destruction was predation (8.6 percent and 15.7 percent respectively) followed by nest erosion (2.2 percent and 6.3 percent respectively). Overall nest success was high but higher for loggerheads (89 percent) than for leatherbacks (78 percent). The main cause of egg mortality for both species was early developmental arrest, followed by predation by ants and ghost crabs. Hatchlings en route to the sea were almost exclusively predated by ghost crabs (4.2 percent of emerged loggerhead hatchlings and 3.2 percent of emerged leatherback hatchlings). It appears that both species benefit from the coastal conservation efforts. When sea turtles leave the nesting beach, either as hatchlings or adults, conservation and monitoring becomes more difficult and sea turtles are exposed to a multitude of threats, including anthropogenic threats. Age classes tend to be spatially separated due to different habitat and dietary requirements. The type of threat sea turtles are exposed to thus depends on the current age class. Offshore sources of mortality in the SWIO were identified and where possible loggerhead and leatherback mortality was quantified and mapped spatially. Loggerheads were mostly exposed to and had the highest mortality in the artisanal fisheries in the SWIO (> 1000 per annum), inshore trawling (ca. 41 per annum), shark nets (protective gill nets) (21.6 ± 6.7 per annum) and the pelagic longline fishery (5.0 ± 4.4 per annum). In contrast, leatherbacks with a pelagic lifestyle, were mostly exposed to pelagic longline fisheries (7.8 ± 7.8 per annum). A spatial analysis of fishing activities indicated that leatherback home ranges overlapped 41percent with pelagic longline fishing activity in the SA EEZ, whereas the overlap between pelagic longliners and loggerhead home ranges was 29 percent. The quantified sources of mortality provide some explanation for the trend in the loggerhead nesting population but not the trend in the leatherback nesting population. Hatchling survivorship to adulthood was estimated to determine the viability of the two nesting populations as well as to determine whether offshore mortality was responsible for the difference in recovery of the two populations. Loggerhead hatchling survivorship to adulthood was estimated at between 2 and 10 per 1000 hatchlings, the minimum requirement for an increasing population. The adopted sophisticated model shows that leatherbacks have a survival rate of 5 to 10 per 1 000 hatchlings. However, this suggests that the population is increasing, but the leatherback population is stable. Perhaps the age to maturity of SA leatherbacks is greater than 12 years, or fisheries-related mortality affects younger age classes than initially thought. It is therefore recommended that the turtle monitoring area is extended to include other potential nesting grounds. In addition, observer or monitoring programs for commercial as well as artisanal fisheries needs to be extended throughout the SWIO to quantify sea turtle mortality. Ultimately a comprehensive multi-regional approach is required for the conservation of these highly migratory species.
- Full Text:
- Date Issued: 2012
Factors contributing to the dropout rate of learners at selected high schools in Kings William's Town
- Dekeza-Tsomo, Ntombikazi Gloria
- Authors: Dekeza-Tsomo, Ntombikazi Gloria
- Date: 2012
- Subjects: High school dropouts -- South Africa -- Kings William's Town , Problem children
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8174 , http://hdl.handle.net/10948/1593 , High school dropouts -- South Africa -- Kings William's Town , Problem children
- Description: Once learners reach high school, they seem to lose focus and become less interested in fulfilling their educational goals. This leads to learner dropout in schools. Yet, the government expects all children to attend school daily and receive the best education so that they can have a bright future. Education prepares the child for life, if the child drops out, he or she will struggle to succeed in life. There are real social reasons that make it difficult for some learners to succeed and lead to them dropping out of school. For example, many learners in South Africa are extremely poor and they dropout because their parents cannot provide for their families. Dropout learners from poor backgrounds also tend to be involved in crime. Young people are under a lot of pressure and consequently, they end up using drugs, smoking cigarettes and drinking alcohol instead of going to school. Teenage stress also contributes to learner dropout. The transition from childhood to adulthood brings challenges, thus making teenagers vulnerable to physical and emotional stress. Many learners do not get the support they need when they are experiencing stress. The high stress levels experienced by learners tend to result in high levels of absenteeism. Pregnancy seems to be another contributing factor to the dropout of learners from school. Thus, learner dropout is a significant problem within the South African context. Not only is learner dropout a problem, but it is linked to many other issues that negatively affect society. This study has examined factors influencing learners to dropout. It employed a qualitative research methodology, using interviews and questionnaires to elicit and investigate the causal factors of learner dropouts. The researcher made use of non-probability sampling because it can be regarded as the only sampling method that makes possible representative sampling design. Purposive sampling was used for the research, because it was convenient for the researcher in terms of time. By using purposive sampling the researcher was able to include participants according to the relevant criteria based on the emerging research questions. The principal, one educator and 18 learners in each of the two high schools were chosen as participants of the study. These participants were coming from two high schools, which are located in King William‟s Town District. Learners who participated in the iv study were chosen from grade 10, 11 and 12. There were six learners chosen per grade. The sampling method used to select learners from grade 10 to 12 and educators was purposive sampling. This type of sampling was used because the researcher wanted rich information from participants and individuals who can express themselves very well about the reasons of learners dropping out at school and also who met the sampling criterion of having had the experience of dropping out of school. The purpose of this study was to investigate factors contributing to the dropout rate of learners at selected high schools in King William‟s Town District. A purposive sampling technique was used to select the participants. The study population was confined to two public high schools in the King William‟s Town District. Using qualitative methodologies, involving a sample of 36 learners, two educators and two principals, the study found multiple motives, associated with individual characteristics of dropouts and social problems emanating from their family background and influence of the community, prompting the learners to dropout. It emerged from the empirical findings of this study that learner dropout is inter alia caused by social factors such as teenage pregnancy, drug abuse, HIV or AIDS infection, gangsterism and learning barriers. These factors are complex issues, which should be handled by skilled people. As learners spend a great deal of their time in the school environment, the educator has become an important role-player to assist learners to alleviate social problems. It is essential that learners with social problems should at an early stage get professional help. The educators who are, due to circumstances, are obliged to help these learners, are not necessarily equipped to give the required assistance. Suggestions and recommendations are espoused to alleviate the situation.
- Full Text:
- Date Issued: 2012
- Authors: Dekeza-Tsomo, Ntombikazi Gloria
- Date: 2012
- Subjects: High school dropouts -- South Africa -- Kings William's Town , Problem children
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8174 , http://hdl.handle.net/10948/1593 , High school dropouts -- South Africa -- Kings William's Town , Problem children
- Description: Once learners reach high school, they seem to lose focus and become less interested in fulfilling their educational goals. This leads to learner dropout in schools. Yet, the government expects all children to attend school daily and receive the best education so that they can have a bright future. Education prepares the child for life, if the child drops out, he or she will struggle to succeed in life. There are real social reasons that make it difficult for some learners to succeed and lead to them dropping out of school. For example, many learners in South Africa are extremely poor and they dropout because their parents cannot provide for their families. Dropout learners from poor backgrounds also tend to be involved in crime. Young people are under a lot of pressure and consequently, they end up using drugs, smoking cigarettes and drinking alcohol instead of going to school. Teenage stress also contributes to learner dropout. The transition from childhood to adulthood brings challenges, thus making teenagers vulnerable to physical and emotional stress. Many learners do not get the support they need when they are experiencing stress. The high stress levels experienced by learners tend to result in high levels of absenteeism. Pregnancy seems to be another contributing factor to the dropout of learners from school. Thus, learner dropout is a significant problem within the South African context. Not only is learner dropout a problem, but it is linked to many other issues that negatively affect society. This study has examined factors influencing learners to dropout. It employed a qualitative research methodology, using interviews and questionnaires to elicit and investigate the causal factors of learner dropouts. The researcher made use of non-probability sampling because it can be regarded as the only sampling method that makes possible representative sampling design. Purposive sampling was used for the research, because it was convenient for the researcher in terms of time. By using purposive sampling the researcher was able to include participants according to the relevant criteria based on the emerging research questions. The principal, one educator and 18 learners in each of the two high schools were chosen as participants of the study. These participants were coming from two high schools, which are located in King William‟s Town District. Learners who participated in the iv study were chosen from grade 10, 11 and 12. There were six learners chosen per grade. The sampling method used to select learners from grade 10 to 12 and educators was purposive sampling. This type of sampling was used because the researcher wanted rich information from participants and individuals who can express themselves very well about the reasons of learners dropping out at school and also who met the sampling criterion of having had the experience of dropping out of school. The purpose of this study was to investigate factors contributing to the dropout rate of learners at selected high schools in King William‟s Town District. A purposive sampling technique was used to select the participants. The study population was confined to two public high schools in the King William‟s Town District. Using qualitative methodologies, involving a sample of 36 learners, two educators and two principals, the study found multiple motives, associated with individual characteristics of dropouts and social problems emanating from their family background and influence of the community, prompting the learners to dropout. It emerged from the empirical findings of this study that learner dropout is inter alia caused by social factors such as teenage pregnancy, drug abuse, HIV or AIDS infection, gangsterism and learning barriers. These factors are complex issues, which should be handled by skilled people. As learners spend a great deal of their time in the school environment, the educator has become an important role-player to assist learners to alleviate social problems. It is essential that learners with social problems should at an early stage get professional help. The educators who are, due to circumstances, are obliged to help these learners, are not necessarily equipped to give the required assistance. Suggestions and recommendations are espoused to alleviate the situation.
- Full Text:
- Date Issued: 2012
Development of a hydraulic sub-model as part of a desktop environmental flow assessment method
- Authors: Desai, Ahmed Yacoob
- Date: 2012
- Subjects: Hydrologic models -- Research -- South Africa Hydraulic engineering -- South Africa Rivers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6041 , http://hdl.handle.net/10962/d1006200
- Description: Countries around the world have been developing ecological policies to protect their water resources and minimise the impacts of development on their river systems. The concept of ‘minimum flows’ was initially established as a solution but it did not provide sufficient protection as all elements of a flow regime were found to be important for the protection of the river ecosystem. “Environmental flows” were developed to determine these flow regimes to maintain a river in some defined ecological condition. Rapid, initial estimates of the quantity component of environmental flows may be determined using the Desktop Reserve Model in South Africa. However, the Desktop Reserve Model is dependent upon the characteristics of the reference natural hydrology used. The advancements in hydraulic and ecological relationships from the past decade have prompted the development of a Revised Desktop Reserve Model (RDRM) that would incorporate these relationships. The research in this thesis presents the development of the hydraulic sub-model for the RDRM. The hydraulic sub-model was designed to produce a realistic representation of the hydraulic conditions using hydraulic parameters/characteristics from readily available information for any part of South Africa. Hydraulic data from past EWR studies were used to estimate the hydraulic parameters. These estimated hydraulic parameters were used to develop hydraulic estimation relationships and these relationships were developed based on a combination of regression and rule-based procedures. The estimation relationships were incorporated into the hydraulic sub-model of the integrated RDRM and assessments of the hydraulic outputs and EWR results were undertaken to assess the ‘applicability’ of the hydraulic sub-model. The hydraulic sub-model was assessed to be at a stage where it can satisfactorily be incorporated in the RDRM and that it is adequately robust in many situations. Recommendations for future work include the refinement of estimation of the channel forming discharge or the use of spatial imagery to check the maximum channel width estimation. It is also proposed that a future version of the hydraulic sub-model could include flow regime change impacts on channel geomorphology and sedimentology so that flow management scenarios can be more effectively assessed.
- Full Text:
- Date Issued: 2012
- Authors: Desai, Ahmed Yacoob
- Date: 2012
- Subjects: Hydrologic models -- Research -- South Africa Hydraulic engineering -- South Africa Rivers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6041 , http://hdl.handle.net/10962/d1006200
- Description: Countries around the world have been developing ecological policies to protect their water resources and minimise the impacts of development on their river systems. The concept of ‘minimum flows’ was initially established as a solution but it did not provide sufficient protection as all elements of a flow regime were found to be important for the protection of the river ecosystem. “Environmental flows” were developed to determine these flow regimes to maintain a river in some defined ecological condition. Rapid, initial estimates of the quantity component of environmental flows may be determined using the Desktop Reserve Model in South Africa. However, the Desktop Reserve Model is dependent upon the characteristics of the reference natural hydrology used. The advancements in hydraulic and ecological relationships from the past decade have prompted the development of a Revised Desktop Reserve Model (RDRM) that would incorporate these relationships. The research in this thesis presents the development of the hydraulic sub-model for the RDRM. The hydraulic sub-model was designed to produce a realistic representation of the hydraulic conditions using hydraulic parameters/characteristics from readily available information for any part of South Africa. Hydraulic data from past EWR studies were used to estimate the hydraulic parameters. These estimated hydraulic parameters were used to develop hydraulic estimation relationships and these relationships were developed based on a combination of regression and rule-based procedures. The estimation relationships were incorporated into the hydraulic sub-model of the integrated RDRM and assessments of the hydraulic outputs and EWR results were undertaken to assess the ‘applicability’ of the hydraulic sub-model. The hydraulic sub-model was assessed to be at a stage where it can satisfactorily be incorporated in the RDRM and that it is adequately robust in many situations. Recommendations for future work include the refinement of estimation of the channel forming discharge or the use of spatial imagery to check the maximum channel width estimation. It is also proposed that a future version of the hydraulic sub-model could include flow regime change impacts on channel geomorphology and sedimentology so that flow management scenarios can be more effectively assessed.
- Full Text:
- Date Issued: 2012
Knowledge retention strategies in selected Southern Africa public broadcasting corporations
- Authors: Dewah, Peterson
- Date: 2012
- Subjects: Knowledge management , Intellectual capital -- Management , Employee retention , Broadcasting -- South Africa , Broadcasting -- Zimbabwe , Broadcasting -- Botswana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11572 , http://hdl.handle.net/10353/438 , Knowledge management , Intellectual capital -- Management , Employee retention , Broadcasting -- South Africa , Broadcasting -- Zimbabwe , Broadcasting -- Botswana
- Description: Knowledge is now regarded as the most important resource surpassing other resources like land and capital. It is a foregone conclusion that knowledge flows out of organizations through various ways such as resignations, retirement and death yet, it does not seem as if organizations are employing strategies to retain such a vital component of production and service delivery. This study investigated the knowledge retention strategies in three Southern Africa Development Community (SADC) public broadcasting organizations of the South African Broadcasting Corporation in South African (SABC), the Department of Broadcasting Services (DBS) in Botswana and the Zimbabwe Broadcasting Corporation (ZBC) in Zimbabwe. The aim of this study was to establish how knowledge is captured and retained at such organizations. The objectives of the study were; to find out the types of strategies the three broadcasting organizations employ to capture and retain knowledge; establish how the three broadcasting organizational cultures enable knowledge acquisition, transfer, sharing and retention; establish the role of ICTs as tools and enablers of knowledge retention, creation, transfer and sharing in the three broadcasting organizations; and to propose recommendations on the best strategies for retention of knowledge in the three public broadcasting organizations as well as suggest areas for further and future research. v The study used the survey method and employed the triangulation design for data gathering. Data were collected from three SADC public broadcasting organizations. The population sample comprised 240 professional staff including 38 managers from different sections of the broadcasting organizations. The researcher collected data by administering a questionnaire to staff, interviews with managers and observations. Documentary analysis was also conducted in order to supplement data and fill in gaps. The researcher was mainly interested in gathering data that would give a comprehensive picture about knowledge retention methods in broadcasting organizations. There were four main findings. First, knowledge management as a relatively new concept and practice has not yet been properly embraced in the public broadcasting organization system in order to capture and retain knowledge that is acquired and generated in the organizations. There are no measures put in place in the organizations to retain the knowledge to ensure that once those who hold vital tacit knowledge are gone, the knowledge may still be available and accessible. Second, the study established that the respective organizational cultures impede on organizational knowledge retention. The study established that there was no culture of knowledge sharing. It also emerged that employees were not free to share their knowledge because of government regulations, prevailing political contexts, mistrust and general lack of incentive to share knowledge. Third, the study established that the organizations have no strategies or systems in place to capture the experts‟ knowledge or the knowledge of experienced staff and vi those approaching retiring age. The Human Resources Departments hold exit interviews that cover issues purely to do with why the person is leaving the organization instead of recording the work experiences and expertise of the departing employees. Fourth, the study revealed that the public broadcasting organizations still lag behind in collaborative and communicative technologies that facilitate knowledge transfer and sharing of tacit knowledge but retention of knowledge generally. The study also found that, some of the organizations studied did not have internet connectivity and websites were not yet functional, which hampered acquisition and sharing of knowledge for retention purposes. The importance of this study is that it has made a contribution and provided literature on knowledge retention strategies for public broadcasting corporations as part of knowledge management practice. On the basis of these findings the study recommended the following: appointment of knowledge management officers, establishment of Communities of Practice, encouraging knowledge sharing between employees, introduction of joint programmes with other broadcasting organizations by managers and their supervision of mentoring programmes; organizations to facilitate acquisition of information and communication technologies that enable knowledge management
- Full Text:
- Date Issued: 2012
- Authors: Dewah, Peterson
- Date: 2012
- Subjects: Knowledge management , Intellectual capital -- Management , Employee retention , Broadcasting -- South Africa , Broadcasting -- Zimbabwe , Broadcasting -- Botswana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11572 , http://hdl.handle.net/10353/438 , Knowledge management , Intellectual capital -- Management , Employee retention , Broadcasting -- South Africa , Broadcasting -- Zimbabwe , Broadcasting -- Botswana
- Description: Knowledge is now regarded as the most important resource surpassing other resources like land and capital. It is a foregone conclusion that knowledge flows out of organizations through various ways such as resignations, retirement and death yet, it does not seem as if organizations are employing strategies to retain such a vital component of production and service delivery. This study investigated the knowledge retention strategies in three Southern Africa Development Community (SADC) public broadcasting organizations of the South African Broadcasting Corporation in South African (SABC), the Department of Broadcasting Services (DBS) in Botswana and the Zimbabwe Broadcasting Corporation (ZBC) in Zimbabwe. The aim of this study was to establish how knowledge is captured and retained at such organizations. The objectives of the study were; to find out the types of strategies the three broadcasting organizations employ to capture and retain knowledge; establish how the three broadcasting organizational cultures enable knowledge acquisition, transfer, sharing and retention; establish the role of ICTs as tools and enablers of knowledge retention, creation, transfer and sharing in the three broadcasting organizations; and to propose recommendations on the best strategies for retention of knowledge in the three public broadcasting organizations as well as suggest areas for further and future research. v The study used the survey method and employed the triangulation design for data gathering. Data were collected from three SADC public broadcasting organizations. The population sample comprised 240 professional staff including 38 managers from different sections of the broadcasting organizations. The researcher collected data by administering a questionnaire to staff, interviews with managers and observations. Documentary analysis was also conducted in order to supplement data and fill in gaps. The researcher was mainly interested in gathering data that would give a comprehensive picture about knowledge retention methods in broadcasting organizations. There were four main findings. First, knowledge management as a relatively new concept and practice has not yet been properly embraced in the public broadcasting organization system in order to capture and retain knowledge that is acquired and generated in the organizations. There are no measures put in place in the organizations to retain the knowledge to ensure that once those who hold vital tacit knowledge are gone, the knowledge may still be available and accessible. Second, the study established that the respective organizational cultures impede on organizational knowledge retention. The study established that there was no culture of knowledge sharing. It also emerged that employees were not free to share their knowledge because of government regulations, prevailing political contexts, mistrust and general lack of incentive to share knowledge. Third, the study established that the organizations have no strategies or systems in place to capture the experts‟ knowledge or the knowledge of experienced staff and vi those approaching retiring age. The Human Resources Departments hold exit interviews that cover issues purely to do with why the person is leaving the organization instead of recording the work experiences and expertise of the departing employees. Fourth, the study revealed that the public broadcasting organizations still lag behind in collaborative and communicative technologies that facilitate knowledge transfer and sharing of tacit knowledge but retention of knowledge generally. The study also found that, some of the organizations studied did not have internet connectivity and websites were not yet functional, which hampered acquisition and sharing of knowledge for retention purposes. The importance of this study is that it has made a contribution and provided literature on knowledge retention strategies for public broadcasting corporations as part of knowledge management practice. On the basis of these findings the study recommended the following: appointment of knowledge management officers, establishment of Communities of Practice, encouraging knowledge sharing between employees, introduction of joint programmes with other broadcasting organizations by managers and their supervision of mentoring programmes; organizations to facilitate acquisition of information and communication technologies that enable knowledge management
- Full Text:
- Date Issued: 2012
Mesozooplankton dynamics in a biogeographical transition zone estuary
- Deyzel, (Shaun) Herklaas Phillipus
- Authors: Deyzel, (Shaun) Herklaas Phillipus
- Date: 2012
- Subjects: Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10687 , http://hdl.handle.net/10948/d1007901 , Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Description: This thesis presents the first intensive community-level investigation of the mesozooplankton from a biogeographical transition zone estuary. The Mgazana Estuary is located along a rural, semi-undeveloped part of South Africa’s east coast, believed to represent a transition zone between the subtropical and warm-temperate biogeographical zones. The research represented in this thesis involves data collected over a five year period between 2002 and 2006, with additional data collection made in 2008. The study focussed on five areas of investigation, the first of which investigated the physico-chemical dynamics of the Mgazana Estuary. The Mgazana Estuary exhibited marked vertical, horizontal and regional structures in the hydrological environment. Prominent vertical and horizontal stratification characterised summer months. A substantial turbidity front was observed in the lower estuary during summer and winter. The upper estuary was marked by considerable variation in multiple variables but especially salinity. These structures appeared to have shifted in position over the horizontal plane, which was attributed to variation in freshwater flow. The second study focused on the spatial dynamics of mesozooplankton in the Mgazana Estuary. The zooplankton was rich and in terms of composition typical of mangrove systems. The Copepoda were dominant, numerically and in terms of taxonomic representation. Calanoids Acartiella natalensis and Pseudodiaptomus hessei characterised middle and upper reaches in summer and mostly upper reaches in winter. On community level, a highly structured assemblage arrangement was observed during summer and winter months. These trends were further scrutinised under the theoretical framework of ecological boundaries. In so doing, an agreeable spatial association emerged between specific assemblages and their environments. These trends were concluded to reflect ecoclinal as well as ecotonal properties, the latter describing interactions over narrow spatial bands of marked changes in turbidity. The third study investigated flooding events as short-lived extreme meteorological events and the influence on zooplankton. Within this regard, second-stage multivariate statistics was used to assess year-to-year variability in assemblage structures on whole-system and regional scales. The impact of two major flooding events that flushed the estuary some days prior to sampling could clearly be elucidated. Flooding emerged as a significant source of inter-annual variability in the zooplankton of the Mgazana Estuary. Second-stage multivariate analysis proved to be an effective analytical strategy for investigating inter-annual variability in species assemblage structures. Results from the preceding study prompted a detailed investigation into the spatio-temporal dynamics of Acartiella natalensis, the most important zooplankton species of the system aimed at elucidating flood responses. Acartiella natalensis showed indication of temporal arrest in association with flooding events in a similar fashion as is observed in seasonal variation trends in estuaries towards its geographical distribution limit south of the study area. It was concluded that A. natalensis was severely affected by floods and the possibility exist for entrainment of entire populations from the estuary during flooding events. The final study tested the hypothesis of post-flood propagation from a resting egg bank in the sediments of the Mgazana Estuary. Preliminary data revealed that numerous eggs were present in the sediments. Nauplii hatched from eggs under laboratory conditions were identified as belonging to the family Acartiidae. The preliminary mode of diapause is presented as a schematic model, emphasising the role of freshwater flow and specific environmental variables. This was the first discovery of resting eggs from a subtropical estuary from South Africa. It is hoped that the findings of this study would give rise to new research initiatives investigating the importance of resting stages in estuarine and coastal Copepoda species and the role such reproductive strategies may play in estuarine functioning.
- Full Text:
- Date Issued: 2012
- Authors: Deyzel, (Shaun) Herklaas Phillipus
- Date: 2012
- Subjects: Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10687 , http://hdl.handle.net/10948/d1007901 , Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Description: This thesis presents the first intensive community-level investigation of the mesozooplankton from a biogeographical transition zone estuary. The Mgazana Estuary is located along a rural, semi-undeveloped part of South Africa’s east coast, believed to represent a transition zone between the subtropical and warm-temperate biogeographical zones. The research represented in this thesis involves data collected over a five year period between 2002 and 2006, with additional data collection made in 2008. The study focussed on five areas of investigation, the first of which investigated the physico-chemical dynamics of the Mgazana Estuary. The Mgazana Estuary exhibited marked vertical, horizontal and regional structures in the hydrological environment. Prominent vertical and horizontal stratification characterised summer months. A substantial turbidity front was observed in the lower estuary during summer and winter. The upper estuary was marked by considerable variation in multiple variables but especially salinity. These structures appeared to have shifted in position over the horizontal plane, which was attributed to variation in freshwater flow. The second study focused on the spatial dynamics of mesozooplankton in the Mgazana Estuary. The zooplankton was rich and in terms of composition typical of mangrove systems. The Copepoda were dominant, numerically and in terms of taxonomic representation. Calanoids Acartiella natalensis and Pseudodiaptomus hessei characterised middle and upper reaches in summer and mostly upper reaches in winter. On community level, a highly structured assemblage arrangement was observed during summer and winter months. These trends were further scrutinised under the theoretical framework of ecological boundaries. In so doing, an agreeable spatial association emerged between specific assemblages and their environments. These trends were concluded to reflect ecoclinal as well as ecotonal properties, the latter describing interactions over narrow spatial bands of marked changes in turbidity. The third study investigated flooding events as short-lived extreme meteorological events and the influence on zooplankton. Within this regard, second-stage multivariate statistics was used to assess year-to-year variability in assemblage structures on whole-system and regional scales. The impact of two major flooding events that flushed the estuary some days prior to sampling could clearly be elucidated. Flooding emerged as a significant source of inter-annual variability in the zooplankton of the Mgazana Estuary. Second-stage multivariate analysis proved to be an effective analytical strategy for investigating inter-annual variability in species assemblage structures. Results from the preceding study prompted a detailed investigation into the spatio-temporal dynamics of Acartiella natalensis, the most important zooplankton species of the system aimed at elucidating flood responses. Acartiella natalensis showed indication of temporal arrest in association with flooding events in a similar fashion as is observed in seasonal variation trends in estuaries towards its geographical distribution limit south of the study area. It was concluded that A. natalensis was severely affected by floods and the possibility exist for entrainment of entire populations from the estuary during flooding events. The final study tested the hypothesis of post-flood propagation from a resting egg bank in the sediments of the Mgazana Estuary. Preliminary data revealed that numerous eggs were present in the sediments. Nauplii hatched from eggs under laboratory conditions were identified as belonging to the family Acartiidae. The preliminary mode of diapause is presented as a schematic model, emphasising the role of freshwater flow and specific environmental variables. This was the first discovery of resting eggs from a subtropical estuary from South Africa. It is hoped that the findings of this study would give rise to new research initiatives investigating the importance of resting stages in estuarine and coastal Copepoda species and the role such reproductive strategies may play in estuarine functioning.
- Full Text:
- Date Issued: 2012