A cyclic approach to business continuity planning
- Authors: Botha, Jacques
- Date: 2002
- Subjects: Data recovery (Computer science) -- Planning , Data protection , Emergency management
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10788 , http://hdl.handle.net/10948/81 , Data recovery (Computer science) -- Planning , Data protection , Emergency management
- Description: The Information Technology (IT) industry has grown and has become an integral part in the world of business today. The importance of information, and IT in particular, will in fact only increase with time (von Solms, 1999). For a large group of organizations computer systems form the basis of their day-to-day functioning (Halliday, Badendorst & von Solms, 1996). These systems evolve at an incredible pace and this brings about a greater need for securing them, as well as the organizational information processed, transmitted and stored. This technological evolution brings about new risks for an organization’s systems and information (Halliday et. al., 1996). If IT fails, it means that the business could fail as well, creating a need for more rigorous IT management (International Business Machines Corporation, 2000). For this reason, executive management must be made aware of the potential consequences that a disaster could have on the organisation (Hawkins,Yen & Chou, 2000). A disaster could be any event that would cause a disruption in the normal day-to-day functioning of an organization. Such an event could range from a natural disaster, like a fire, an earthquake or a flood, to something more trivial, like a virus or system malfunction (Hawkins et. al., 2000). During the 1980’s a discipline known as Disaster Recovery Planning (DRP) emerged to protect an organization’s data centre, which was central to the organisation’s IT based structure, from the effects of disasters. This solution, however, focussed only on the protection of the data centre. During the early 1990’s the focus shifted towards distributed computing and client/server technology. Data centre protection and recovery were no longer enough to ensure survival. Organizations needed to ensure the continuation of their mission critical processes to support their continued goal of operations (IBM Global Services, 1999). Organizations now had to ensure that their mission critical functions could continue while the data centre was recovering from a disaster. A different approach was required. It is for this reason that Business Continuity Planning (BCP) was accepted as a formal discipline (IBM Global Services, 1999). To ensure that business continues as usual, an organization must have a plan in place that will help them ensure both the continuation and recovery of critical business processes and the recovery of the data centre, should a disaster strike (Moore, 1995). Wilson (2000) defines a business continuity plan as “a set of procedures developed for the entire enterprise, outlining the actions to be taken by the IT organization, executive staff, and the various business units in order to quickly resume operations in the event of a service interruption or an outage”. With markets being highly competitive as they are, an organization needs a detailed listing of steps to follow to ensure minimal loss due to downtime. This is very important for maintaining its competitive advantage and public stature (Wilson, 2000). The fact that the company’s reputation is at stake requires executive management to take continuity planning very serious (IBM Global Services, 1999). Ensuring continuity of business processes and recovering the IT services of an organization is not the sole responsibility of the IT department. Therefore management should be aware that they could be held liable for any consequences resulting from a disaster (Kearvell-White, 1996). Having a business continuity plan in place is important to the entire organization, as everyone, from executive management to the employees, stands to benefit from it (IBM Global Services, 1999). Despite this, numerous organizations do not have a business continuity plan in place. Organizations neglecting to develop a plan put themselves at tremendous risk and stand to loose everything (Kearvell-White, 1996).
- Full Text:
- Date Issued: 2002
- Authors: Botha, Jacques
- Date: 2002
- Subjects: Data recovery (Computer science) -- Planning , Data protection , Emergency management
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10788 , http://hdl.handle.net/10948/81 , Data recovery (Computer science) -- Planning , Data protection , Emergency management
- Description: The Information Technology (IT) industry has grown and has become an integral part in the world of business today. The importance of information, and IT in particular, will in fact only increase with time (von Solms, 1999). For a large group of organizations computer systems form the basis of their day-to-day functioning (Halliday, Badendorst & von Solms, 1996). These systems evolve at an incredible pace and this brings about a greater need for securing them, as well as the organizational information processed, transmitted and stored. This technological evolution brings about new risks for an organization’s systems and information (Halliday et. al., 1996). If IT fails, it means that the business could fail as well, creating a need for more rigorous IT management (International Business Machines Corporation, 2000). For this reason, executive management must be made aware of the potential consequences that a disaster could have on the organisation (Hawkins,Yen & Chou, 2000). A disaster could be any event that would cause a disruption in the normal day-to-day functioning of an organization. Such an event could range from a natural disaster, like a fire, an earthquake or a flood, to something more trivial, like a virus or system malfunction (Hawkins et. al., 2000). During the 1980’s a discipline known as Disaster Recovery Planning (DRP) emerged to protect an organization’s data centre, which was central to the organisation’s IT based structure, from the effects of disasters. This solution, however, focussed only on the protection of the data centre. During the early 1990’s the focus shifted towards distributed computing and client/server technology. Data centre protection and recovery were no longer enough to ensure survival. Organizations needed to ensure the continuation of their mission critical processes to support their continued goal of operations (IBM Global Services, 1999). Organizations now had to ensure that their mission critical functions could continue while the data centre was recovering from a disaster. A different approach was required. It is for this reason that Business Continuity Planning (BCP) was accepted as a formal discipline (IBM Global Services, 1999). To ensure that business continues as usual, an organization must have a plan in place that will help them ensure both the continuation and recovery of critical business processes and the recovery of the data centre, should a disaster strike (Moore, 1995). Wilson (2000) defines a business continuity plan as “a set of procedures developed for the entire enterprise, outlining the actions to be taken by the IT organization, executive staff, and the various business units in order to quickly resume operations in the event of a service interruption or an outage”. With markets being highly competitive as they are, an organization needs a detailed listing of steps to follow to ensure minimal loss due to downtime. This is very important for maintaining its competitive advantage and public stature (Wilson, 2000). The fact that the company’s reputation is at stake requires executive management to take continuity planning very serious (IBM Global Services, 1999). Ensuring continuity of business processes and recovering the IT services of an organization is not the sole responsibility of the IT department. Therefore management should be aware that they could be held liable for any consequences resulting from a disaster (Kearvell-White, 1996). Having a business continuity plan in place is important to the entire organization, as everyone, from executive management to the employees, stands to benefit from it (IBM Global Services, 1999). Despite this, numerous organizations do not have a business continuity plan in place. Organizations neglecting to develop a plan put themselves at tremendous risk and stand to loose everything (Kearvell-White, 1996).
- Full Text:
- Date Issued: 2002
Exploring the suitability of the evaluation criteria used in the MPT projects, by looking at hard and soft components of development programmes
- Authors: Ncapai, Wandile
- Date: 2002
- Subjects: Community development -- South Africa -- Eastern Cape , Community development , Economic development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3397 , http://hdl.handle.net/10962/d1018255
- Description: The study explores the suitability of the evaluation criteria used in Microprojects Programme Trust (MPT), by looking at hard and soft components of the development programme. In this sense hard components of development refer to those components of projects that are tangible and can be physically observed and can bring material changes to the life of the community. Soft components of development refer to those components of projects that bring qualitative transformation to the life of the community, i.e. increased levels of awareness, human well-being and the empowerment process that addresses the community's abstract needs, these are not tangible and often cannot be physically observed. Midway through its contract periods MPT evaluate all projects. The purpose of these mid term evaluations is to make recommendations to MPT on future approaches and methodology for community development and operations. The mid-term evaluation also influences the distribution and allocation of resources and funding. It was therefore vital that the criteria used are subject to tests and critical analysis so as to assess their validity. The assessment of the mid-term evaluation criteria used in MPT projects has been to further determine the appropriateness or suitability of the evaluation criteria as an instrument to measure and guide the MPT community development approach in the Eastern Cape. The method used was to conduct focus group discussions so as to get an insight into the local community situation as well as to assess non-tangible improvements and changes that have occurred in the life of the community as a result of the project. The information generated was used to compare what the community believe they achieved with what the official mid-term evaluation reports indicate was assessed and achieved and that was contrasted with what the literature recommends should have been assessed. The study found that the mid-term evaluations conducted on MPT projects have no social context in which the evaluations themselves were conducted. The terms of reference and criteria were based on the programme design which was formulated and compiled by the European Union without the participation of the local South African community. The findings also indicated that projects become unsuccessful or partly successful if the "soft" components which have a bearing on social and economic realities are neglected. The thesis ends with recommendations on how the mid-term evaluations as well as MPT programme can be developed to be more responsive to the needs as identified by the communities themselves. It is strongly believed that this study will provide a valuable contribution towards increasing the ability of MPT programme to bring about both material and qualitative transformation to the I ives of the disadvantaged community of the Eastern Cape whilst ensuring that the mid-term evaluations are developed and shaped to become an appropriate instrument to measure and guide MPT programme approach to community development.
- Full Text:
- Date Issued: 2002
- Authors: Ncapai, Wandile
- Date: 2002
- Subjects: Community development -- South Africa -- Eastern Cape , Community development , Economic development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3397 , http://hdl.handle.net/10962/d1018255
- Description: The study explores the suitability of the evaluation criteria used in Microprojects Programme Trust (MPT), by looking at hard and soft components of the development programme. In this sense hard components of development refer to those components of projects that are tangible and can be physically observed and can bring material changes to the life of the community. Soft components of development refer to those components of projects that bring qualitative transformation to the life of the community, i.e. increased levels of awareness, human well-being and the empowerment process that addresses the community's abstract needs, these are not tangible and often cannot be physically observed. Midway through its contract periods MPT evaluate all projects. The purpose of these mid term evaluations is to make recommendations to MPT on future approaches and methodology for community development and operations. The mid-term evaluation also influences the distribution and allocation of resources and funding. It was therefore vital that the criteria used are subject to tests and critical analysis so as to assess their validity. The assessment of the mid-term evaluation criteria used in MPT projects has been to further determine the appropriateness or suitability of the evaluation criteria as an instrument to measure and guide the MPT community development approach in the Eastern Cape. The method used was to conduct focus group discussions so as to get an insight into the local community situation as well as to assess non-tangible improvements and changes that have occurred in the life of the community as a result of the project. The information generated was used to compare what the community believe they achieved with what the official mid-term evaluation reports indicate was assessed and achieved and that was contrasted with what the literature recommends should have been assessed. The study found that the mid-term evaluations conducted on MPT projects have no social context in which the evaluations themselves were conducted. The terms of reference and criteria were based on the programme design which was formulated and compiled by the European Union without the participation of the local South African community. The findings also indicated that projects become unsuccessful or partly successful if the "soft" components which have a bearing on social and economic realities are neglected. The thesis ends with recommendations on how the mid-term evaluations as well as MPT programme can be developed to be more responsive to the needs as identified by the communities themselves. It is strongly believed that this study will provide a valuable contribution towards increasing the ability of MPT programme to bring about both material and qualitative transformation to the I ives of the disadvantaged community of the Eastern Cape whilst ensuring that the mid-term evaluations are developed and shaped to become an appropriate instrument to measure and guide MPT programme approach to community development.
- Full Text:
- Date Issued: 2002
New views on the Jurassic Clarens Formation: volcano-sedimentary interaction
- Holzforster, Frank, Holzforster, Heike W, Marsh, Julian S
- Authors: Holzforster, Frank , Holzforster, Heike W , Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , abstract
- Identifier: http://hdl.handle.net/10962/132716 , vital:36874
- Description: The Lower Jurassic Clarens Formation of the Great Karoo Basin is usually viewed in the literature as a aeolian and, in places, fluvio-aeolian deposit of tremendous thickness variation form 0-250 m thickness. Interaction with the overlying Karoo Flood Basalts, particularly in the Eastern Cape area and in Lesotho, has been noted but was never a major topic. Relatively widespread pyroclastic deposits sandwiched between the Clarens Formation and the Karoo Flood Basalts have been interpreted as flood-lahars.
- Full Text:
- Date Issued: 2002
- Authors: Holzforster, Frank , Holzforster, Heike W , Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , abstract
- Identifier: http://hdl.handle.net/10962/132716 , vital:36874
- Description: The Lower Jurassic Clarens Formation of the Great Karoo Basin is usually viewed in the literature as a aeolian and, in places, fluvio-aeolian deposit of tremendous thickness variation form 0-250 m thickness. Interaction with the overlying Karoo Flood Basalts, particularly in the Eastern Cape area and in Lesotho, has been noted but was never a major topic. Relatively widespread pyroclastic deposits sandwiched between the Clarens Formation and the Karoo Flood Basalts have been interpreted as flood-lahars.
- Full Text:
- Date Issued: 2002
Economic impact of international labour migration on Lesotho's development, 1986-1998: towards an international labour migration policy for the Southern African region
- Authors: Maro, Mkasafari Grace
- Date: 2002
- Subjects: Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1058 , http://hdl.handle.net/10962/d1007496 , Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Description: The aim of the thesis is to identify the pressures that contributed to the rise in international labour migration in Lesotho, and to investigate how these pressures are impacting upon the modernization process in the country, particularly at a time when employment opportunities are scarce in the southern African region. International labour migration has been used as a development tool throughout history, but especially in the 20th century by developing countries with dual labour markets. Newly independent developing countries with dual labour markets adapted the strategy of import substitution industrialization (lSI), with an emphasis on protecting infant industries and promoting pro-labour policies. In the post-colonial period the international demand for lowskilled workers rose, particularly in the North (developed countries), and in mineral rich countries including the oil exporters and South Africa, and the newly industrialising countries in East Asia. International labour migration to these countries was adapted as an integral development tool by the governments of the lSI countries. Most migrants were low-skilled and temporary workers in the destination countries. Although no multilateral institutional framework existed, usually both the sending and receiving countries adapted unilateral and bilateral migration policies to guarantee the gains from migration. Workers were thus "protected" to varying degrees under such agreements. From the 1970s, the North experienced a slowdown in the growth in demand for unskilled workers. In the 1980s, many lSI countries experienced devastating economic crises that forced them to abandon the lSI policy and adapt the export-led industrialisation (EOI) policy with an emphasis on trade liberalization. The switch from lSI to EOI in developing countries with dual labour markets led to the downsizing of public sector employment, the removal of marketing boards formally used by small-scale agricultural farmers, and the expansion of export processing zones (EPZs). These outcomes resulted in a rise in push internal migration, and international migration from these countries especially to other developing countries. At the same time, since the late 1980s, capital has acquired greatly enhanced mobility at the global level. The adaptation of EOI and the full mobility of capital at the global level altered the institutional structure within which labour migration was governed both nationally, and internationally. At the national level stricter unilateral policies were reinforced by receiving countries for low-skilled labour, while less strict policies applied for skilled labour. These remain in operation in conjunction with the earlier bilateral agreements. At the international level, there remains a lack of policy to regulate international labour migration. Under the current enhanced mobility of capital, international migrants are thus left vulnerable. Lesotho fits this pattern. Faced with a dual economy and an abundance of semi-skilled labour, Lesotho has been a principal supplier of labour to the South Africa's mining industry since its independence. Lesotho's industrial diversification thus mirrors South Africa's industrial diversification. In the lSI phase (1968 - 1987), international labour migration became the most important tool of economic welfare generation in Lesotho. Bilateral agreements were signed in the early 1970s between Lesotho and South Africa to guarantee the gains from migration. Since the late I980s, the mining industry in South Africa began to downsize production and employment. Fewer novice miners from Lesotho were recruited to work in South Africa. The adaptation of the EOI policy in Lesotho in 1987 introduced EPZ industrialization and trade liberalization. Nevertheless, the retrenchment of mine workers from South Africa is occurring at a time when Lesotho is experiencing an employment crisis. The political independence of South Africa in 1994 was accompanied by stricter international migration policies by the new democratic government of South Africa. Most migrant workers in South Africa are thus now faced with a two-door policy (of the earlier bilateral agreements and the amendments to the Aliens Control Act). This system has left migrant workers vulnerable to exploitation by both employers and the law (police) in South Africa. Nevertheless, international migration from Lesotho to South Africa continues to expand, particularly of the new type of migration - semiskilled female workers in the services sector. At the same time, South Africa is also experiencing an employment crisis. The most important policy implications are, firstly, that migration is subject to the same "casualisation" as other work, with the effects made worse by the "statelessness" of migrants, who are most vulnerable to exploitation. Secondly, multilateralism is needed (e.g., SADC) and holistic, multilateral policies are required. It is clear that under the new global division of labour ad hoc policy towards international labour migration is ineffective.
- Full Text:
- Date Issued: 2002
- Authors: Maro, Mkasafari Grace
- Date: 2002
- Subjects: Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1058 , http://hdl.handle.net/10962/d1007496 , Migrant labor -- South Africa , Migrant labor -- Lesotho , Foreign workers -- South Africa , Miners -- South Africa , Miners -- Labor unions -- South Africa
- Description: The aim of the thesis is to identify the pressures that contributed to the rise in international labour migration in Lesotho, and to investigate how these pressures are impacting upon the modernization process in the country, particularly at a time when employment opportunities are scarce in the southern African region. International labour migration has been used as a development tool throughout history, but especially in the 20th century by developing countries with dual labour markets. Newly independent developing countries with dual labour markets adapted the strategy of import substitution industrialization (lSI), with an emphasis on protecting infant industries and promoting pro-labour policies. In the post-colonial period the international demand for lowskilled workers rose, particularly in the North (developed countries), and in mineral rich countries including the oil exporters and South Africa, and the newly industrialising countries in East Asia. International labour migration to these countries was adapted as an integral development tool by the governments of the lSI countries. Most migrants were low-skilled and temporary workers in the destination countries. Although no multilateral institutional framework existed, usually both the sending and receiving countries adapted unilateral and bilateral migration policies to guarantee the gains from migration. Workers were thus "protected" to varying degrees under such agreements. From the 1970s, the North experienced a slowdown in the growth in demand for unskilled workers. In the 1980s, many lSI countries experienced devastating economic crises that forced them to abandon the lSI policy and adapt the export-led industrialisation (EOI) policy with an emphasis on trade liberalization. The switch from lSI to EOI in developing countries with dual labour markets led to the downsizing of public sector employment, the removal of marketing boards formally used by small-scale agricultural farmers, and the expansion of export processing zones (EPZs). These outcomes resulted in a rise in push internal migration, and international migration from these countries especially to other developing countries. At the same time, since the late 1980s, capital has acquired greatly enhanced mobility at the global level. The adaptation of EOI and the full mobility of capital at the global level altered the institutional structure within which labour migration was governed both nationally, and internationally. At the national level stricter unilateral policies were reinforced by receiving countries for low-skilled labour, while less strict policies applied for skilled labour. These remain in operation in conjunction with the earlier bilateral agreements. At the international level, there remains a lack of policy to regulate international labour migration. Under the current enhanced mobility of capital, international migrants are thus left vulnerable. Lesotho fits this pattern. Faced with a dual economy and an abundance of semi-skilled labour, Lesotho has been a principal supplier of labour to the South Africa's mining industry since its independence. Lesotho's industrial diversification thus mirrors South Africa's industrial diversification. In the lSI phase (1968 - 1987), international labour migration became the most important tool of economic welfare generation in Lesotho. Bilateral agreements were signed in the early 1970s between Lesotho and South Africa to guarantee the gains from migration. Since the late I980s, the mining industry in South Africa began to downsize production and employment. Fewer novice miners from Lesotho were recruited to work in South Africa. The adaptation of the EOI policy in Lesotho in 1987 introduced EPZ industrialization and trade liberalization. Nevertheless, the retrenchment of mine workers from South Africa is occurring at a time when Lesotho is experiencing an employment crisis. The political independence of South Africa in 1994 was accompanied by stricter international migration policies by the new democratic government of South Africa. Most migrant workers in South Africa are thus now faced with a two-door policy (of the earlier bilateral agreements and the amendments to the Aliens Control Act). This system has left migrant workers vulnerable to exploitation by both employers and the law (police) in South Africa. Nevertheless, international migration from Lesotho to South Africa continues to expand, particularly of the new type of migration - semiskilled female workers in the services sector. At the same time, South Africa is also experiencing an employment crisis. The most important policy implications are, firstly, that migration is subject to the same "casualisation" as other work, with the effects made worse by the "statelessness" of migrants, who are most vulnerable to exploitation. Secondly, multilateralism is needed (e.g., SADC) and holistic, multilateral policies are required. It is clear that under the new global division of labour ad hoc policy towards international labour migration is ineffective.
- Full Text:
- Date Issued: 2002
A preliminary investigation into the patterns of performance on a computerized adaptive test battery implications for admissions and placement
- Authors: Vorster, Marlene
- Date: 2002
- Subjects: Universities and colleges -- Admission , Advanced placement programs (Education) , Computer adaptive testing , Universities and colleges -- Entrance requirements
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11030 , http://hdl.handle.net/10948/285 , Universities and colleges -- Admission , Advanced placement programs (Education) , Computer adaptive testing , Universities and colleges -- Entrance requirements
- Description: The fallibility of human judgment in the making of decisions requires the use of tests to enhance decision-making processes. Although testing is surrounded with issues of bias and fairness, it remains the best means of facilitating decisions over more subjective alternatives. As a country in transition, all facets of South African society are being transformed. The changes taking place within the tertiary education system to redress the legacy of Apartheid, coincide with an international trend of transforming higher education. One important area that is being transformed relates to university entrance requirements and admissions procedures. In South Africa, these were traditionally based on matriculation performance, which has been found to be a more variable predictor of academic success for historically disadvantaged students. Alternative or revised admissions procedures have been implemented at universities throughout the country, in conjunction with academic development programmes. However, it is argued in this dissertation that a paradigm shift is necessary to conceptualise admissions and placement assessment in a developmentally oriented way. Furthermore, it is motivated that it is important to keep abreast of advances in theory, such as item response theory (IRT) and technology, such as computerized adaptive testing (CAT), in test development to enhance the effectiveness of selecting and placing learners in tertiary programmes. This study focuses on investigating the use of the Accuplacer Computerized Placement Tests (CPTs), an adaptive test battery that was developed in the USA, to facilitate unbiased and fair admissions, placement and development decisions in the transforming South African context. The battery has been implemented at a university in the Eastern Cape and its usefulness was investigated for 193 participants, divided into two groups of degree programmes, depending on whether or not admission to the degree required mathematics as a matriculation subject. Mathematics based degree programme learners (n = 125) wrote three and non-mathematics based degree programme learners (n = 68) wrote two tests of the Accuplacer test battery. Correlations were computed between the Accuplacer scores and matriculation performance, and between the Accuplacer scores, matriculation performance and academic results. All yielded significant positive relationships excepting for the one subtest of the Accuplacer with academic performance for the non-mathematics based degree group. Multiple correlations for both groups indicated that the Accuplacer scores and matriculation results contribute unique information about academic performance. Cluster analysis for both groups yielded three underlying patterns of performance in the data sets. An attempt was made to validate the cluster groups internally through a MANOVA and single-factor ANOVAs. It was found that Accuplacer subtests and matriculation results do discriminate to an extent among clusters of learners in both groups of degree programmes investigated. Clusters were described in terms of demographic information and it was determined that the factors of culture and home language and how they relate to cluster group membership need further investigation. The main suggestion flowing from these findings is that an attempt be made to confirm the results with a larger sample size and for different cultural and language groups.
- Full Text:
- Date Issued: 2002
- Authors: Vorster, Marlene
- Date: 2002
- Subjects: Universities and colleges -- Admission , Advanced placement programs (Education) , Computer adaptive testing , Universities and colleges -- Entrance requirements
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11030 , http://hdl.handle.net/10948/285 , Universities and colleges -- Admission , Advanced placement programs (Education) , Computer adaptive testing , Universities and colleges -- Entrance requirements
- Description: The fallibility of human judgment in the making of decisions requires the use of tests to enhance decision-making processes. Although testing is surrounded with issues of bias and fairness, it remains the best means of facilitating decisions over more subjective alternatives. As a country in transition, all facets of South African society are being transformed. The changes taking place within the tertiary education system to redress the legacy of Apartheid, coincide with an international trend of transforming higher education. One important area that is being transformed relates to university entrance requirements and admissions procedures. In South Africa, these were traditionally based on matriculation performance, which has been found to be a more variable predictor of academic success for historically disadvantaged students. Alternative or revised admissions procedures have been implemented at universities throughout the country, in conjunction with academic development programmes. However, it is argued in this dissertation that a paradigm shift is necessary to conceptualise admissions and placement assessment in a developmentally oriented way. Furthermore, it is motivated that it is important to keep abreast of advances in theory, such as item response theory (IRT) and technology, such as computerized adaptive testing (CAT), in test development to enhance the effectiveness of selecting and placing learners in tertiary programmes. This study focuses on investigating the use of the Accuplacer Computerized Placement Tests (CPTs), an adaptive test battery that was developed in the USA, to facilitate unbiased and fair admissions, placement and development decisions in the transforming South African context. The battery has been implemented at a university in the Eastern Cape and its usefulness was investigated for 193 participants, divided into two groups of degree programmes, depending on whether or not admission to the degree required mathematics as a matriculation subject. Mathematics based degree programme learners (n = 125) wrote three and non-mathematics based degree programme learners (n = 68) wrote two tests of the Accuplacer test battery. Correlations were computed between the Accuplacer scores and matriculation performance, and between the Accuplacer scores, matriculation performance and academic results. All yielded significant positive relationships excepting for the one subtest of the Accuplacer with academic performance for the non-mathematics based degree group. Multiple correlations for both groups indicated that the Accuplacer scores and matriculation results contribute unique information about academic performance. Cluster analysis for both groups yielded three underlying patterns of performance in the data sets. An attempt was made to validate the cluster groups internally through a MANOVA and single-factor ANOVAs. It was found that Accuplacer subtests and matriculation results do discriminate to an extent among clusters of learners in both groups of degree programmes investigated. Clusters were described in terms of demographic information and it was determined that the factors of culture and home language and how they relate to cluster group membership need further investigation. The main suggestion flowing from these findings is that an attempt be made to confirm the results with a larger sample size and for different cultural and language groups.
- Full Text:
- Date Issued: 2002
The independent high rate algal pond as a unit operation in tertiary wastewater treatment
- Authors: Clark, Stewart James
- Date: 2002
- Subjects: Algae -- Biotechnology , Sewage -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4092 , http://hdl.handle.net/10962/d1007805
- Description: The development of the High Rate Algal Pond (HRAP) as an independent tertiary treatment unit operation for phosphate and nitrate removal is reported. A novel Integrated Algal Ponding System (lAPS) design is proposed for nutrient removal from the effluents of both a conventional domestic sewage treatment plant and from an Advanced Integrated Wastewater Ponding System (AIWPS). The viability of an independently operated HRAP has been identified and termed the Independent High Rate Algal Pond (l-HRAP). A 500 m² pilot 1- HRAP was operated in such a way as to facilitate the precipitation of calcium phosphate, known to be controlled by pH (greater than 9.4) and resulting in final phosphate levels of less than 1 mg.L⁻¹ as P0₄-P. The incorporation of the I-HRAP into a denitrification process was also investigated. Continuously fed column reactors, utilising algal biomass as a carbon source, showed that the heterotrophic bacterial community dominant in the anaerobic algal sludge were denitrifying the nitrate in the feed. It was demonstrated that as the cultures were stressed (using increased nitrate concentrations, anaerobiosis and light starvation) total polysaccharide (TPS) concentrations increased, with a notable increase 111 the exopolysaccharide (EPS) fraction. These experiments corroborated the hypothesis that harvested microalgal biomass can be manipulated to produce, and release, exopolymeric substances under stress conditions, and which may serve as carbon source for denitrification. In both batch flask studies and in laboratory-scale reactor systems, harvested microalgal biomass from an HRAP was shown to produce exopolymeric substances under stress conditions. Initial high loading-rates of greater than 20 mg.L⁻¹ NO₃-N resulted in double the amount of exopolysaccharide production than in flasks with initial low loading-rates (less than 5 mg.L⁻¹ NO₃-N). Making use of an upflow anaerobic sludge blanket-type degrading-bed reactor, and an anaerobic, flooded trickle filter (ANTRIC) receiving HRAP effluent, the relationship between denitrification and the changes in polysaccharide content was investigated. This phenomenon has considerable beneficial implications in biological wastewater treatment systems where high nitrate concentration in the final effluent is a potential mitigating factor. Identification of the heterotrophic bacteria active in the denitrification process was attempted. This study presents a first report on the development and operation of the I-HRAP and has been followed by a technical-scale pilot plant evaluation of the process in the tertiary treatment of domestic wastewaters.
- Full Text:
- Date Issued: 2002
- Authors: Clark, Stewart James
- Date: 2002
- Subjects: Algae -- Biotechnology , Sewage -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4092 , http://hdl.handle.net/10962/d1007805
- Description: The development of the High Rate Algal Pond (HRAP) as an independent tertiary treatment unit operation for phosphate and nitrate removal is reported. A novel Integrated Algal Ponding System (lAPS) design is proposed for nutrient removal from the effluents of both a conventional domestic sewage treatment plant and from an Advanced Integrated Wastewater Ponding System (AIWPS). The viability of an independently operated HRAP has been identified and termed the Independent High Rate Algal Pond (l-HRAP). A 500 m² pilot 1- HRAP was operated in such a way as to facilitate the precipitation of calcium phosphate, known to be controlled by pH (greater than 9.4) and resulting in final phosphate levels of less than 1 mg.L⁻¹ as P0₄-P. The incorporation of the I-HRAP into a denitrification process was also investigated. Continuously fed column reactors, utilising algal biomass as a carbon source, showed that the heterotrophic bacterial community dominant in the anaerobic algal sludge were denitrifying the nitrate in the feed. It was demonstrated that as the cultures were stressed (using increased nitrate concentrations, anaerobiosis and light starvation) total polysaccharide (TPS) concentrations increased, with a notable increase 111 the exopolysaccharide (EPS) fraction. These experiments corroborated the hypothesis that harvested microalgal biomass can be manipulated to produce, and release, exopolymeric substances under stress conditions, and which may serve as carbon source for denitrification. In both batch flask studies and in laboratory-scale reactor systems, harvested microalgal biomass from an HRAP was shown to produce exopolymeric substances under stress conditions. Initial high loading-rates of greater than 20 mg.L⁻¹ NO₃-N resulted in double the amount of exopolysaccharide production than in flasks with initial low loading-rates (less than 5 mg.L⁻¹ NO₃-N). Making use of an upflow anaerobic sludge blanket-type degrading-bed reactor, and an anaerobic, flooded trickle filter (ANTRIC) receiving HRAP effluent, the relationship between denitrification and the changes in polysaccharide content was investigated. This phenomenon has considerable beneficial implications in biological wastewater treatment systems where high nitrate concentration in the final effluent is a potential mitigating factor. Identification of the heterotrophic bacteria active in the denitrification process was attempted. This study presents a first report on the development and operation of the I-HRAP and has been followed by a technical-scale pilot plant evaluation of the process in the tertiary treatment of domestic wastewaters.
- Full Text:
- Date Issued: 2002
Alkane oxidation using metallophthalocyanine as homogeneous catalysts
- Authors: Grootboom, Natasha Denise
- Date: 2002
- Subjects: Oxidation , Alkanes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4449 , http://hdl.handle.net/10962/d1007794
- Description: Iron polychlorophthalocyanine (FePc(Cl)₁₆) and tetrasulfophthalocyanine ([M¹¹TSPc]⁴) complexes of iron, cobalt and manganese are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), chloroperoxybenzoic acid (CPBA) and hydrogen peroxide as oxidants. Catalysis using the FePc(Cl)₁₆ was performed in a dimethylformamide:dichloromethane (3 :7) solvent mixture. For the [Fe¹¹TSPc]⁴⁻, [Co¹¹TSPc]⁻ and [Mn¹¹TSPc]⁴⁻catalysts, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative percentage yields, percentage selectivity and overall percentage conversion of the products depended on types of oxidant, or catalyst, concentrations of substrate or catalysts and temperature. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. Of the four catalysts investigated [Fe¹¹TSPc]⁴⁻ yielded the highest overall percentage conversion of 20%.The mechanism of the oxidation of cyclohexane in the presence of the FePc(Cl)₁₆ and [M¹¹TSPc]⁴⁻ involves the oxidation of these catalysts, forming an Fe(IlI) phthalocyanine species as an intermediate. Electrocatalysis using [Co¹¹TSPc]⁴⁻ as catalyst, employed an aqueous pH 7 buffer medium for electro-oxidation of 4-pentenoic acid. An enone is suggested as the only oxidation product of 4-pentenoic acid. No degradation of [Co¹¹TSPc]⁴⁻ was observed during the electrocatalytic process. In this process water was used as a source of oxygen therefore eliminating the production of by products from oxidant as in the case of TBHP and CPBA. This system was studied In an attempt to set up conditions for alkane electrocatalytic oxidation.
- Full Text:
- Date Issued: 2002
- Authors: Grootboom, Natasha Denise
- Date: 2002
- Subjects: Oxidation , Alkanes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4449 , http://hdl.handle.net/10962/d1007794
- Description: Iron polychlorophthalocyanine (FePc(Cl)₁₆) and tetrasulfophthalocyanine ([M¹¹TSPc]⁴) complexes of iron, cobalt and manganese are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), chloroperoxybenzoic acid (CPBA) and hydrogen peroxide as oxidants. Catalysis using the FePc(Cl)₁₆ was performed in a dimethylformamide:dichloromethane (3 :7) solvent mixture. For the [Fe¹¹TSPc]⁴⁻, [Co¹¹TSPc]⁻ and [Mn¹¹TSPc]⁴⁻catalysts, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative percentage yields, percentage selectivity and overall percentage conversion of the products depended on types of oxidant, or catalyst, concentrations of substrate or catalysts and temperature. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. Of the four catalysts investigated [Fe¹¹TSPc]⁴⁻ yielded the highest overall percentage conversion of 20%.The mechanism of the oxidation of cyclohexane in the presence of the FePc(Cl)₁₆ and [M¹¹TSPc]⁴⁻ involves the oxidation of these catalysts, forming an Fe(IlI) phthalocyanine species as an intermediate. Electrocatalysis using [Co¹¹TSPc]⁴⁻ as catalyst, employed an aqueous pH 7 buffer medium for electro-oxidation of 4-pentenoic acid. An enone is suggested as the only oxidation product of 4-pentenoic acid. No degradation of [Co¹¹TSPc]⁴⁻ was observed during the electrocatalytic process. In this process water was used as a source of oxygen therefore eliminating the production of by products from oxidant as in the case of TBHP and CPBA. This system was studied In an attempt to set up conditions for alkane electrocatalytic oxidation.
- Full Text:
- Date Issued: 2002
The effect of selenium in the detoxification of the microcystin hepatotoxins
- Authors: Downs, Kerry
- Date: 2002
- Subjects: Cynaobacterial toxins , Microcystins , Selenium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11070 , http://hdl.handle.net/10948/284 , Cynaobacterial toxins , Microcystins , Selenium
- Description: Blooms of cyanobacteria have been known to cause illness in humans and death in wild and domestic animals. One of the toxins produced by cyanobacteria is microcystin, which is a potent hepatotoxin. Microcystin is taken up by bile acid transporters in the intestine and transported into the liver. After exposure to acute doses of microcystin, severe haemorrhage has been observed along with apoptotic and necrotic hepatocytes. The cytoskeletal structure of the hepatocytes is disrupted and oxidative stress is induced. Selenium, a known anti-oxidant, has been shown to induce increased activity of glutathione peroxidase. Glutathione peroxidase removes peroxides from cells protecting them from oxidative stress. This study set out to determine if selenium could play a role in preventing the damage to mice livers due to microcystin toxin. The protective role of selenium was explored in three main studies: in the first study, the ability of selenium to increase the survival time of mice exposed to a lethal dose of toxin was determined. In the second study the mice were exposed to sublethal chronic doses of toxin over 30 days. The ability of selenium to minimise liver damage under these conditions was determined. The final study investigated the mechanism of the protective effect of selenium. The results of the first study suggested that selenium could extend survival time. In the second study the selenium supplemented mice showed a reduction in the extent of the increase in liver weight and a decrease in the amount of lipid peroxidation induced compared to the mice that received only toxin. The histology of the selenium supplemented mice also showed a decrease in the severity and amount of morphological changes in the liver. The third study indicated that the protection shown by selenium might be mediated by an increase in the glutathione peroxidase (GPX) activity in selenium supplemented mice. This increase in GPX activity would increase the removal of the lipid hydroperoxides and prevent the damage they would cause in the cell. A further result indicated an increase in glutathione S-transferase in only the toxin control mice when compared to the selenium supplemented and control mice. ii In conclusion selenium offers protection against microcystin but further studies need to be done to provide statistically valid results to clarify the level of protection.
- Full Text:
- Date Issued: 2002
- Authors: Downs, Kerry
- Date: 2002
- Subjects: Cynaobacterial toxins , Microcystins , Selenium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11070 , http://hdl.handle.net/10948/284 , Cynaobacterial toxins , Microcystins , Selenium
- Description: Blooms of cyanobacteria have been known to cause illness in humans and death in wild and domestic animals. One of the toxins produced by cyanobacteria is microcystin, which is a potent hepatotoxin. Microcystin is taken up by bile acid transporters in the intestine and transported into the liver. After exposure to acute doses of microcystin, severe haemorrhage has been observed along with apoptotic and necrotic hepatocytes. The cytoskeletal structure of the hepatocytes is disrupted and oxidative stress is induced. Selenium, a known anti-oxidant, has been shown to induce increased activity of glutathione peroxidase. Glutathione peroxidase removes peroxides from cells protecting them from oxidative stress. This study set out to determine if selenium could play a role in preventing the damage to mice livers due to microcystin toxin. The protective role of selenium was explored in three main studies: in the first study, the ability of selenium to increase the survival time of mice exposed to a lethal dose of toxin was determined. In the second study the mice were exposed to sublethal chronic doses of toxin over 30 days. The ability of selenium to minimise liver damage under these conditions was determined. The final study investigated the mechanism of the protective effect of selenium. The results of the first study suggested that selenium could extend survival time. In the second study the selenium supplemented mice showed a reduction in the extent of the increase in liver weight and a decrease in the amount of lipid peroxidation induced compared to the mice that received only toxin. The histology of the selenium supplemented mice also showed a decrease in the severity and amount of morphological changes in the liver. The third study indicated that the protection shown by selenium might be mediated by an increase in the glutathione peroxidase (GPX) activity in selenium supplemented mice. This increase in GPX activity would increase the removal of the lipid hydroperoxides and prevent the damage they would cause in the cell. A further result indicated an increase in glutathione S-transferase in only the toxin control mice when compared to the selenium supplemented and control mice. ii In conclusion selenium offers protection against microcystin but further studies need to be done to provide statistically valid results to clarify the level of protection.
- Full Text:
- Date Issued: 2002
"The wife of Lucifer" : women and evil in Charles Dickens
- Authors: Ebelthite, Candice Axell
- Date: 2002
- Subjects: Dickens, Charles, 1812-1870 -- Characters -- Women Evil in literature Women in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2189 , http://hdl.handle.net/10962/d1002231
- Description: This thesis examines Dickens's presentation of evil women. In the course of my reading I discovered that most of the evil women in his novels are mothers, or mother-figures, a finding which altered the nature of my interpretation and led to closer examination of these characters, rather than the prostitutes and criminals who may have been viewed negatively by Nineteenth century society and thereby condemned as evil. Among the many unsympathetically portrayed mothers and mother-figures in Dickens's works, the three that are most interesting are Lady Dedlock, Miss Havisham, and Mrs Skewton. Madame Defarge initiates the discussion, however, as a seminal figure among the many evil women in the novels. Psychoanalytical and socio-historic readings grounded in Nineteenth century conceptions of womanhood provide background material for this thesis. Though useful and informative, however, these areas of study are not sufficient in themselves. The theory that shapes the arguments of this thesis is defined by Steven Cohan, who argues strongly that the demand for psychological coherence as a requisite of character obscures the imaginative power of character as textual construct, and who both refutes and develops character theory as it is argued by Baruch Hochman. Cohan's theory is also finally closer to that outlined by Thomas Docherty, who provides a complex reading of character as ultimately "unknowable".
- Full Text:
- Date Issued: 2002
- Authors: Ebelthite, Candice Axell
- Date: 2002
- Subjects: Dickens, Charles, 1812-1870 -- Characters -- Women Evil in literature Women in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2189 , http://hdl.handle.net/10962/d1002231
- Description: This thesis examines Dickens's presentation of evil women. In the course of my reading I discovered that most of the evil women in his novels are mothers, or mother-figures, a finding which altered the nature of my interpretation and led to closer examination of these characters, rather than the prostitutes and criminals who may have been viewed negatively by Nineteenth century society and thereby condemned as evil. Among the many unsympathetically portrayed mothers and mother-figures in Dickens's works, the three that are most interesting are Lady Dedlock, Miss Havisham, and Mrs Skewton. Madame Defarge initiates the discussion, however, as a seminal figure among the many evil women in the novels. Psychoanalytical and socio-historic readings grounded in Nineteenth century conceptions of womanhood provide background material for this thesis. Though useful and informative, however, these areas of study are not sufficient in themselves. The theory that shapes the arguments of this thesis is defined by Steven Cohan, who argues strongly that the demand for psychological coherence as a requisite of character obscures the imaginative power of character as textual construct, and who both refutes and develops character theory as it is argued by Baruch Hochman. Cohan's theory is also finally closer to that outlined by Thomas Docherty, who provides a complex reading of character as ultimately "unknowable".
- Full Text:
- Date Issued: 2002
The growth and reproduction of the freshwater limpet Burnupia stenochorias (Pulmonata, Ancylidae), and an evaluation of its use as an ecotoxicology indicator in whole effluent testing
- Davies-Coleman, H D (Heather D)
- Authors: Davies-Coleman, H D (Heather D)
- Date: 2002
- Subjects: Ancylidae Effluent quality Toxicity testing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5703 , http://hdl.handle.net/10962/d1005389
- Description: For the protection of the ecological Reserve in South Africa, the proposed introduction of compulsory toxicity testing in the licensing of effluent discharges necessitates the development of whole effluent toxicity testing. The elucidation of the effects of effluent on the local indigenous populations of organisms is essential before hazard and risk assessment can be undertaken. The limpet Burnupia stenochorias, prevalent in the Eastern Cape of South Africa, was chosen to represent the freshwater molluscs as a potential toxicity indicator. Using potassium dichromate (as a reference toxicant) and a textile whole effluent, the suitability of B. stenochorias was assessed under both acute and chronic toxicity conditions in the laboratory. In support of the toxicity studies, aspects of the biology of B. stenochorias were investigated under both natural and laboratory conditions. Using Principal Component and Discriminant Function Analyses, the relative shell morphometrics of three feral populations of B. stenochorias were found to vary. Length was shown to adequately represent growth of the shell, although the inclusion of width measurements is more statistically preferable. Two of the feral populations, one in impacted water, were studied weekly for 52 weeks to assess natural population dynamics. Based on the Von Bertalanffy Growth Equation, estimates of growth and longevity were made for this species, with growth highly seasonal. Age is not easily discerned from shell size. Egg laying occurred all year round, with early summer (peak egg lay), mid summer (a second, smaller peak in egg lay), and winter (limited presence of eggs) phases. In toxicity testing, consideration is given to the choice of the test organism based on age and sexual development. Consequently, the sexual development of B. stenochorias relative to shell length was determined with the aid of histological examinations of transverse sections of limpets, of all sizes, collected over one year. Limpets less than 3mm shell length were found to be immature in the development of the oocytes and spermatozoa, and were later chosen for acute toxicity tests. A laboratory diet was developed, for both culturing and maintaining of the limpets during toxicity tests; however, the diet requires optimisation. Under laboratory conditions, growth was linear, and individual fecundity highly variable. Successful methods for the collection of limpets from naturally occurring populations, and their acclimation to the laboratory were developed. Three B. stenochorias populations, representing different hydrological and water quality conditions, were compared to a laboratory population (maintained for three years) in their responses to the textile whole effluent and potassium dichromate. Under acute conditions, variability of mortality between limpet populations and between seasons was consistent with acceptable international standards. However, seasonal differences between feral limpets were apparent, with early summer limpets significantly more susceptible to both potassium dichromate and textile effluent than winter limpets. Although mortality occurred within the effluent at all concentrations, no 96 hour LC₅₀ values were obtained. The chronic toxicity effects of the textile whole effluent were assessed over the entire life cycle of B. stenochorias, based on survival, growth and reproductive effects. Lower concentrations of effluent (# 10%) gave greater variability of responses and toxicity than higher concentrations, with a 43 day LC₅₀ of 3.9% effluent. The No Observed Effect Concentrations for survival (over 43 days) were calculated in consecutive years as 0.1% and 1% effluent. Survival is considered a useful tool for determining toxicity endpoints using B. stenochorias. Limpet growth remained linear in effluent, with an apparent stimulation of growth at the 3-10% effluent concentration, confusing the toxicity and variability assessments. The possible addition of nutrients from the effluent points to either a potential inadequacy of the food quality provided in the chronic assessment, or the presence in the effluent of growth stimulants. Growth was also found to be too variable to allow adequate statistical conclusions about the toxicity of the effluent, although it is suggested that growth may be useful in the assessment of single compounds. Despite large individual variability in fecundity, statistical differences were discernible between effluent concentrations. The application of fecundity of B. stenochorias in hazard assessment therefore warrants further investigation. It was concluded that an assessment of textile whole effluent toxicity to B. stenochorias over an entire life cycle, and an F1 generation, is unnecessary. The development of the bucket/plastic bag method for both acute and chronic toxicity assessment of B. stenochorias was useful. In the final assessment of the usefulness of B. stenochorias as a toxicity indicator, toxicity endpoints were compared with those of the standard laboratory organism Daphnia pulex. Both in acute and chronic toxicity, B. stenochorias was found to be more sensitive. B. stenochorias is therefore considered valuable as a South African freshwater molluscan ecotoxicological indicator, with a place in hazard assessment, although further development and research is necessary before the limpet can be effectively used.
- Full Text:
- Date Issued: 2002
- Authors: Davies-Coleman, H D (Heather D)
- Date: 2002
- Subjects: Ancylidae Effluent quality Toxicity testing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5703 , http://hdl.handle.net/10962/d1005389
- Description: For the protection of the ecological Reserve in South Africa, the proposed introduction of compulsory toxicity testing in the licensing of effluent discharges necessitates the development of whole effluent toxicity testing. The elucidation of the effects of effluent on the local indigenous populations of organisms is essential before hazard and risk assessment can be undertaken. The limpet Burnupia stenochorias, prevalent in the Eastern Cape of South Africa, was chosen to represent the freshwater molluscs as a potential toxicity indicator. Using potassium dichromate (as a reference toxicant) and a textile whole effluent, the suitability of B. stenochorias was assessed under both acute and chronic toxicity conditions in the laboratory. In support of the toxicity studies, aspects of the biology of B. stenochorias were investigated under both natural and laboratory conditions. Using Principal Component and Discriminant Function Analyses, the relative shell morphometrics of three feral populations of B. stenochorias were found to vary. Length was shown to adequately represent growth of the shell, although the inclusion of width measurements is more statistically preferable. Two of the feral populations, one in impacted water, were studied weekly for 52 weeks to assess natural population dynamics. Based on the Von Bertalanffy Growth Equation, estimates of growth and longevity were made for this species, with growth highly seasonal. Age is not easily discerned from shell size. Egg laying occurred all year round, with early summer (peak egg lay), mid summer (a second, smaller peak in egg lay), and winter (limited presence of eggs) phases. In toxicity testing, consideration is given to the choice of the test organism based on age and sexual development. Consequently, the sexual development of B. stenochorias relative to shell length was determined with the aid of histological examinations of transverse sections of limpets, of all sizes, collected over one year. Limpets less than 3mm shell length were found to be immature in the development of the oocytes and spermatozoa, and were later chosen for acute toxicity tests. A laboratory diet was developed, for both culturing and maintaining of the limpets during toxicity tests; however, the diet requires optimisation. Under laboratory conditions, growth was linear, and individual fecundity highly variable. Successful methods for the collection of limpets from naturally occurring populations, and their acclimation to the laboratory were developed. Three B. stenochorias populations, representing different hydrological and water quality conditions, were compared to a laboratory population (maintained for three years) in their responses to the textile whole effluent and potassium dichromate. Under acute conditions, variability of mortality between limpet populations and between seasons was consistent with acceptable international standards. However, seasonal differences between feral limpets were apparent, with early summer limpets significantly more susceptible to both potassium dichromate and textile effluent than winter limpets. Although mortality occurred within the effluent at all concentrations, no 96 hour LC₅₀ values were obtained. The chronic toxicity effects of the textile whole effluent were assessed over the entire life cycle of B. stenochorias, based on survival, growth and reproductive effects. Lower concentrations of effluent (# 10%) gave greater variability of responses and toxicity than higher concentrations, with a 43 day LC₅₀ of 3.9% effluent. The No Observed Effect Concentrations for survival (over 43 days) were calculated in consecutive years as 0.1% and 1% effluent. Survival is considered a useful tool for determining toxicity endpoints using B. stenochorias. Limpet growth remained linear in effluent, with an apparent stimulation of growth at the 3-10% effluent concentration, confusing the toxicity and variability assessments. The possible addition of nutrients from the effluent points to either a potential inadequacy of the food quality provided in the chronic assessment, or the presence in the effluent of growth stimulants. Growth was also found to be too variable to allow adequate statistical conclusions about the toxicity of the effluent, although it is suggested that growth may be useful in the assessment of single compounds. Despite large individual variability in fecundity, statistical differences were discernible between effluent concentrations. The application of fecundity of B. stenochorias in hazard assessment therefore warrants further investigation. It was concluded that an assessment of textile whole effluent toxicity to B. stenochorias over an entire life cycle, and an F1 generation, is unnecessary. The development of the bucket/plastic bag method for both acute and chronic toxicity assessment of B. stenochorias was useful. In the final assessment of the usefulness of B. stenochorias as a toxicity indicator, toxicity endpoints were compared with those of the standard laboratory organism Daphnia pulex. Both in acute and chronic toxicity, B. stenochorias was found to be more sensitive. B. stenochorias is therefore considered valuable as a South African freshwater molluscan ecotoxicological indicator, with a place in hazard assessment, although further development and research is necessary before the limpet can be effectively used.
- Full Text:
- Date Issued: 2002
Iron perchlorophthalocyanine and tetrasulfophthalocyanine catalyzed oxidation of cyclohexane using hydrogen peroxide, chloroperoxybenzoic acid and tert-butylhydroperoxide as oxidants
- Grootboom, Natasha, Nyokong, Tebello
- Authors: Grootboom, Natasha , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289606 , vital:56653 , xlink:href="https://doi.org/10.1016/S1381-1169(01)00404-6"
- Description: Polychlorophthalocyanine (Cl16PcFeII) and tetrasulfophthalocyanine ([FeIITSPc]4−) complexes of iron are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA) and hydrogen peroxide as oxidants. Catalysis using the Cl16PcFeII was performed in a dimethylformamide:dichloromethane (3:7) solvent mixture. For the [FeIITSPc]4−catalyst, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative yields of the products depended on oxidant and the catalyst. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. The mechanism of the oxidation of cyclohexane in the presence of the Cl16PcFeII and [FeIITSPc]4− involves the oxidation of these catalysts, forming an Fe(III) phthalocyanine species as an intermediate. Higher yields were observed when [FeTSPc]4− was employed as a catalyst, which is more soluble than the perchlorinated iron phthalocyanine catalyst.
- Full Text:
- Date Issued: 2002
- Authors: Grootboom, Natasha , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289606 , vital:56653 , xlink:href="https://doi.org/10.1016/S1381-1169(01)00404-6"
- Description: Polychlorophthalocyanine (Cl16PcFeII) and tetrasulfophthalocyanine ([FeIITSPc]4−) complexes of iron are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA) and hydrogen peroxide as oxidants. Catalysis using the Cl16PcFeII was performed in a dimethylformamide:dichloromethane (3:7) solvent mixture. For the [FeIITSPc]4−catalyst, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative yields of the products depended on oxidant and the catalyst. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. The mechanism of the oxidation of cyclohexane in the presence of the Cl16PcFeII and [FeIITSPc]4− involves the oxidation of these catalysts, forming an Fe(III) phthalocyanine species as an intermediate. Higher yields were observed when [FeTSPc]4− was employed as a catalyst, which is more soluble than the perchlorinated iron phthalocyanine catalyst.
- Full Text:
- Date Issued: 2002
The determination of a strategy for the implementation of learnerships in the catalytic converter canning industry in the Eastern Cape
- Authors: Heather, Keith Buxmann
- Date: 2002
- Subjects: Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10851 , http://hdl.handle.net/10948/117 , Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Description: The Eastern Cape Region, once had sufficient job seekers with automotive component manufacturing skills and experience. Indications are that this pool has been desiccated. The draining of skills out of the area is starting to affect growth potential and competitiveness in the industry in the area. In 1998, the Skills Development Act was passed to implement the National Skills Development Plan, and to encourage employers to train personnel. The strategy promotes a three faceted approach to encourage the development of skills; Workplace Skills Development Plans, Learnerships and Sector Specific Initiatives. This study will focus on the implementation of learnerships in the Catalytic Converter Canning Industry. The aim of this research is to verify the skills shortages; identify which skills are required by the Catalytic Converter Canning Industry in the Eastern Cape and propose a strategy of addressing these needs by means of learnerships. By studying the Legislation supporting the National Skills Development Plan, conducting a literature study, and interviewing knowledgeable people in the industry, the skills requirements of the industry were identified. Thereafter, a questionnaire was drawn up and completed together with representatives from Eberspächer South Africa, Faurecia Exhaust Systems South Africa, Precision Exhaust Systems and Tenneco Automotive South Africa, the active manufacturers of catalytic converters, for OEM’s worldwide, who are based in the Eastern Cape Region. The empirical study confirmed the findings of the research and skills deficiencies were identified. In conclusion, a strategy is proposed whereby the Catalytic Converter Canning Industry could address the skills shortage by the implementation and development of learnerships.
- Full Text:
- Date Issued: 2002
- Authors: Heather, Keith Buxmann
- Date: 2002
- Subjects: Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10851 , http://hdl.handle.net/10948/117 , Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Description: The Eastern Cape Region, once had sufficient job seekers with automotive component manufacturing skills and experience. Indications are that this pool has been desiccated. The draining of skills out of the area is starting to affect growth potential and competitiveness in the industry in the area. In 1998, the Skills Development Act was passed to implement the National Skills Development Plan, and to encourage employers to train personnel. The strategy promotes a three faceted approach to encourage the development of skills; Workplace Skills Development Plans, Learnerships and Sector Specific Initiatives. This study will focus on the implementation of learnerships in the Catalytic Converter Canning Industry. The aim of this research is to verify the skills shortages; identify which skills are required by the Catalytic Converter Canning Industry in the Eastern Cape and propose a strategy of addressing these needs by means of learnerships. By studying the Legislation supporting the National Skills Development Plan, conducting a literature study, and interviewing knowledgeable people in the industry, the skills requirements of the industry were identified. Thereafter, a questionnaire was drawn up and completed together with representatives from Eberspächer South Africa, Faurecia Exhaust Systems South Africa, Precision Exhaust Systems and Tenneco Automotive South Africa, the active manufacturers of catalytic converters, for OEM’s worldwide, who are based in the Eastern Cape Region. The empirical study confirmed the findings of the research and skills deficiencies were identified. In conclusion, a strategy is proposed whereby the Catalytic Converter Canning Industry could address the skills shortage by the implementation and development of learnerships.
- Full Text:
- Date Issued: 2002
A multivariate model of the offence behaviours of South African serial killers
- Authors: Hodgskiss, Brin Allan
- Date: 2013-05-14
- Subjects: Serial murderers -- South Africa -- Psychology Criminal behavior
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3169 , http://hdl.handle.net/10962/d1007793
- Description: It was hypothesised that there would be behavioural consistencies in the offences of South African serial killers. The themes underlying these observable differences can help us understand the nature of these offences. Crime scene data was ohtained from police records, and structured, in-depth offender interviews. 73 offences, committed by 13 offenders, were analysed. The analysis used Smallest Space Analysis (SSA), a Multidimensional scaling (MDS) procedure. This analysis revealed systematic patterns of behaviour in the offences. It was found that the focus of these offences is an impersonal, hostile, and act-focused murder were the victim is treated as a depersonalised object. Empirical support for an underlying thematic structure to these offences was also provided. The offence themes identified relate to the nature of the actions committed during the offence, and the function these actions had for the offender. These fmdings thus support the hypothesis that these offences will display meaningful behavioural variation. These findings have direct utility in the investigation and study of serial killing in South Aflica. They also provide the basis for comparison with previously suggested typologies of serial killing, and indicate directions for future research into this phenomenon in the South African setting. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Hodgskiss, Brin Allan
- Date: 2013-05-14
- Subjects: Serial murderers -- South Africa -- Psychology Criminal behavior
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3169 , http://hdl.handle.net/10962/d1007793
- Description: It was hypothesised that there would be behavioural consistencies in the offences of South African serial killers. The themes underlying these observable differences can help us understand the nature of these offences. Crime scene data was ohtained from police records, and structured, in-depth offender interviews. 73 offences, committed by 13 offenders, were analysed. The analysis used Smallest Space Analysis (SSA), a Multidimensional scaling (MDS) procedure. This analysis revealed systematic patterns of behaviour in the offences. It was found that the focus of these offences is an impersonal, hostile, and act-focused murder were the victim is treated as a depersonalised object. Empirical support for an underlying thematic structure to these offences was also provided. The offence themes identified relate to the nature of the actions committed during the offence, and the function these actions had for the offender. These fmdings thus support the hypothesis that these offences will display meaningful behavioural variation. These findings have direct utility in the investigation and study of serial killing in South Aflica. They also provide the basis for comparison with previously suggested typologies of serial killing, and indicate directions for future research into this phenomenon in the South African setting. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
Asthenospheric and lithospheric sources for Mesozoic dolerites from Liberia (Africa): trace element and isotopic evidence
- Dupuy, C, Marsh, J, Dostal, J, Michard, A, Testa, S
- Authors: Dupuy, C , Marsh, J , Dostal, J , Michard, A , Testa, S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140422 , vital:37887 , https://doi.org/10.1016/0012-821X(88)90067-2
- Description: Combined elemental, and Sr and Nd isotopic data are presented for Mesozoic dolerite dikes of Liberia (Africa) which are related to the initial stage of opening of the Atlantic Ocean.
- Full Text: false
- Date Issued: 2002
- Authors: Dupuy, C , Marsh, J , Dostal, J , Michard, A , Testa, S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140422 , vital:37887 , https://doi.org/10.1016/0012-821X(88)90067-2
- Description: Combined elemental, and Sr and Nd isotopic data are presented for Mesozoic dolerite dikes of Liberia (Africa) which are related to the initial stage of opening of the Atlantic Ocean.
- Full Text: false
- Date Issued: 2002
Policy and practice : an activity systems' analysis of a further diploma in education (technology)
- Thomen, Eva Christine Salzmann
- Authors: Thomen, Eva Christine Salzmann
- Date: 2002
- Subjects: Action theory Teachers -- Training of -- South Africa Technology -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1854 , http://hdl.handle.net/10962/d1004525
- Description: This research examines, within the interpretive paradigm, how emerging educational policy in an in-service educator education programme, namely, a Further Diploma in Education (Technology), is implemented and practiced by educators in the classroom. Technology is a new learning area in the South African curriculum that aims to develop learners' technological skills and promote the practical application of Science and Mathematics. Technology is seen as a way of developing a productive workforce that can design, realise and evaluate technological problems in a global economy. Engestrom's version of Activity Theory was used as the conceptual framework. Activity Theory focuses on 'activity' as a unit of analysis that captures the individual in context. This research focuses on the lecturers' and the students' actions in the programme, and the educators' and the learners' actions in the classroom. The research design was an eclectic case study consisting of two embedded cases within a single larger case namely, in-service educator education. Multiple single cases were selected within the two embedded cases. Trustworthiness and authenticity were addressed through the triangulation of data using mUltiple sources and methods of data collection. Data were analysed and interpreted in a hermeneutic-like process that emerged through gradual induction over time. The findings of the research suggest that the in-service educator education programme did not promote the effective implementation of educational policy. Major challenges to the effective implementation of educational policy include: the formulation and implementation of an INSET programme during rapid educational policy change, the under-preparedness and language difficulties of the participating educators that constrained policy implementation in the INSET programme and the classroom, the role of organisational rules in shaping the activities in the INSET programme and the classroom, and the broader community'S contribution to resource constraints in the classroom. This research suggests that the participating educators are not likely to be major change agents in the transformation of education in South Africa. This concurs with other research findings that suggest that educator education is a weak intervention incapable of overcoming the shortcomings of the educators' own personal schooling or the impact of work experience.
- Full Text:
- Date Issued: 2002
- Authors: Thomen, Eva Christine Salzmann
- Date: 2002
- Subjects: Action theory Teachers -- Training of -- South Africa Technology -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1854 , http://hdl.handle.net/10962/d1004525
- Description: This research examines, within the interpretive paradigm, how emerging educational policy in an in-service educator education programme, namely, a Further Diploma in Education (Technology), is implemented and practiced by educators in the classroom. Technology is a new learning area in the South African curriculum that aims to develop learners' technological skills and promote the practical application of Science and Mathematics. Technology is seen as a way of developing a productive workforce that can design, realise and evaluate technological problems in a global economy. Engestrom's version of Activity Theory was used as the conceptual framework. Activity Theory focuses on 'activity' as a unit of analysis that captures the individual in context. This research focuses on the lecturers' and the students' actions in the programme, and the educators' and the learners' actions in the classroom. The research design was an eclectic case study consisting of two embedded cases within a single larger case namely, in-service educator education. Multiple single cases were selected within the two embedded cases. Trustworthiness and authenticity were addressed through the triangulation of data using mUltiple sources and methods of data collection. Data were analysed and interpreted in a hermeneutic-like process that emerged through gradual induction over time. The findings of the research suggest that the in-service educator education programme did not promote the effective implementation of educational policy. Major challenges to the effective implementation of educational policy include: the formulation and implementation of an INSET programme during rapid educational policy change, the under-preparedness and language difficulties of the participating educators that constrained policy implementation in the INSET programme and the classroom, the role of organisational rules in shaping the activities in the INSET programme and the classroom, and the broader community'S contribution to resource constraints in the classroom. This research suggests that the participating educators are not likely to be major change agents in the transformation of education in South Africa. This concurs with other research findings that suggest that educator education is a weak intervention incapable of overcoming the shortcomings of the educators' own personal schooling or the impact of work experience.
- Full Text:
- Date Issued: 2002
Critical literacy in South Africa : possibilities and constraints in 2002
- Authors: Prinsloo, J , Janks, H
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6330 , http://hdl.handle.net/10962/d1008475
- Description: This article examines the Curriculum documents produced in South Africa since the election of a democratic government in 1994 in order to consider the possibilities they create for the inclusion of critical literacy in the teaching of home languages. This discussion is set against an analysis of the apartheid curriculum documents prior to 1994 and a consideration of the ongoing inequalities in the provision of human and material resources across the system. Despite real constraints with regard to implementation, it is argued that the new Curriculum effects a significant break with the past and makes a positive contribution to transforming language education.
- Full Text:
- Date Issued: 2002
- Authors: Prinsloo, J , Janks, H
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6330 , http://hdl.handle.net/10962/d1008475
- Description: This article examines the Curriculum documents produced in South Africa since the election of a democratic government in 1994 in order to consider the possibilities they create for the inclusion of critical literacy in the teaching of home languages. This discussion is set against an analysis of the apartheid curriculum documents prior to 1994 and a consideration of the ongoing inequalities in the provision of human and material resources across the system. Despite real constraints with regard to implementation, it is argued that the new Curriculum effects a significant break with the past and makes a positive contribution to transforming language education.
- Full Text:
- Date Issued: 2002
John Jolly : the Grahamstown bell founder
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6173 , http://hdl.handle.net/10962/d1012364 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 2002
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6173 , http://hdl.handle.net/10962/d1012364 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 2002
The adaptation of the Clark (1997) treatment for social phobia into a group therapy format, and a preliminary evaluation
- Authors: Kannan, Swetha
- Date: 2002
- Subjects: Social phobia -- Treatment , Group psychotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3109 , http://hdl.handle.net/10962/d1004547 , Social phobia -- Treatment , Group psychotherapy
- Description: Clark and Wells (1995) constructed a comprehensive cognitive model of social phobic behaviour, in terms of which social phobic behaviour is activated and maintained by a system consisting of negative thoughts and beliefs, anxiety s)mptoms, avoidance and safety behaviours, and processing of self as a social object. The interaction of these elements creates a series of vicious circles which escalate and which keep the phobic individual in a state of chronic -disability, either because they chronically avoid significant social situations or because they find themselves incapacitated by anxiety when they enter them. The Clark and Wells (1995) treatment programme is designed to alleviate the social phobia by targeting the components that form the vicious maintenance cycle and replacing these by new patterns of cognition and behaviour. This treatment programme was designed for individual treatment, and the present study adapted it to a group format. Seven social phobic university students participated in the adapted group treatment format over the course of 13, 2-hour group sessions. Regular assessment of participants' response to the programme was carried out weekly and at two follow-up assessments, with the use of a series of questionnaires. In addition, sessions were audio taped and videotaped, facilitators took notes during sessions and keep records made by participants of their homework exercises. Individual case studies were written for all participants (including two non-completers) in which case narratives were juxtaposed against their responses to each of the self-report questionnaires. These we used as a basis for evaluating the validity of the Clark and Wells theoretical model and in examining the effectiveness of the treatment programme in bringing to awareness and interrupting the cycles that maintained the phobic behaviour. It is concluded that the group programme showed evidence of being very effective and, a group treatment manual was constructed so that it can be employed clinically and in future research.
- Full Text:
- Date Issued: 2002
- Authors: Kannan, Swetha
- Date: 2002
- Subjects: Social phobia -- Treatment , Group psychotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3109 , http://hdl.handle.net/10962/d1004547 , Social phobia -- Treatment , Group psychotherapy
- Description: Clark and Wells (1995) constructed a comprehensive cognitive model of social phobic behaviour, in terms of which social phobic behaviour is activated and maintained by a system consisting of negative thoughts and beliefs, anxiety s)mptoms, avoidance and safety behaviours, and processing of self as a social object. The interaction of these elements creates a series of vicious circles which escalate and which keep the phobic individual in a state of chronic -disability, either because they chronically avoid significant social situations or because they find themselves incapacitated by anxiety when they enter them. The Clark and Wells (1995) treatment programme is designed to alleviate the social phobia by targeting the components that form the vicious maintenance cycle and replacing these by new patterns of cognition and behaviour. This treatment programme was designed for individual treatment, and the present study adapted it to a group format. Seven social phobic university students participated in the adapted group treatment format over the course of 13, 2-hour group sessions. Regular assessment of participants' response to the programme was carried out weekly and at two follow-up assessments, with the use of a series of questionnaires. In addition, sessions were audio taped and videotaped, facilitators took notes during sessions and keep records made by participants of their homework exercises. Individual case studies were written for all participants (including two non-completers) in which case narratives were juxtaposed against their responses to each of the self-report questionnaires. These we used as a basis for evaluating the validity of the Clark and Wells theoretical model and in examining the effectiveness of the treatment programme in bringing to awareness and interrupting the cycles that maintained the phobic behaviour. It is concluded that the group programme showed evidence of being very effective and, a group treatment manual was constructed so that it can be employed clinically and in future research.
- Full Text:
- Date Issued: 2002
pH study of the electrocatalytic SO2 detection at a glassy carbon electrode modified with iron (II) tetrasulfophthalocyanine
- Thamae, Mamothibe, Westbroek, Philippe, Nyokong, Tebello
- Authors: Thamae, Mamothibe , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304786 , vital:58490 , xlink:href="https://doi.org/10.1007/s00604-002-0914-8"
- Description: The electrocatalytic determination of SO2 is studied as a function of pH at a glassy carbon electrode modified with iron(II)tetrasulfophthalocyanine ([Fe(II)TSPc]4−). It was found in the literature that depending on pH, SO2·xH2O, HSO3 − and/or SO3 2− are the main compounds in solution, that these compounds behave differently at the electrode surface, and that the condition of the electrode surface is stable over the entire pH-range. The use of SO2(g) or sodium sulfite as starting material did result in identical curves except in the pH range from 7.5–9.0. A possible explanation could be given by proposing that SO2·xH2O is very unstable in the presence of SO3 2−. In strongly acidic medium, SO2·xH2O is the main compound, which can be oxidized as well as reduced with exchange of two electrons. HSO3 − is the main compound at pH = 4 and can also be oxidized and reduced with exchange of, respectively, two and four electrons. In alkaline solution sulfite is the main compound and can only be oxidized, also under exchange of two electrons. Detection limits are in the range of 4.0 ± 0.1 × 10−5 and 7.5 ± 0.1 × 10−5 mol L−1, dependent of pH and of the type of reaction (oxidation or reduction) used.
- Full Text:
- Date Issued: 2002
- Authors: Thamae, Mamothibe , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304786 , vital:58490 , xlink:href="https://doi.org/10.1007/s00604-002-0914-8"
- Description: The electrocatalytic determination of SO2 is studied as a function of pH at a glassy carbon electrode modified with iron(II)tetrasulfophthalocyanine ([Fe(II)TSPc]4−). It was found in the literature that depending on pH, SO2·xH2O, HSO3 − and/or SO3 2− are the main compounds in solution, that these compounds behave differently at the electrode surface, and that the condition of the electrode surface is stable over the entire pH-range. The use of SO2(g) or sodium sulfite as starting material did result in identical curves except in the pH range from 7.5–9.0. A possible explanation could be given by proposing that SO2·xH2O is very unstable in the presence of SO3 2−. In strongly acidic medium, SO2·xH2O is the main compound, which can be oxidized as well as reduced with exchange of two electrons. HSO3 − is the main compound at pH = 4 and can also be oxidized and reduced with exchange of, respectively, two and four electrons. In alkaline solution sulfite is the main compound and can only be oxidized, also under exchange of two electrons. Detection limits are in the range of 4.0 ± 0.1 × 10−5 and 7.5 ± 0.1 × 10−5 mol L−1, dependent of pH and of the type of reaction (oxidation or reduction) used.
- Full Text:
- Date Issued: 2002
Design, evaluation and comparison of evolution and reinforcement learning models
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002