The mandibular gland secretions and ovarial development of worker honeybees (Apis Mellifera) in the Eastern Cape Province of South Africa
- Authors: Reece, Sacha Louise
- Date: 2001
- Subjects: Honeybee -- South Africa -- Eastern Cape , Honeybee -- Behavior , Honeybee -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5729 , http://hdl.handle.net/10962/d1005415 , Honeybee -- South Africa -- Eastern Cape , Honeybee -- Behavior , Honeybee -- Physiology
- Description: The Eastern Cape is an area in which Apis mellifera capensis, A. m. scutellata and their hybrid are known to naturally occur. I investigated the mandibular gland profiles and ovarial development of queenright workers from 4 localities. Their queens were then removed to determine how these aspects changed upon queen loss. In addition, drifted bees were analysed in the same way to determine how these factors changed once they had gained entry to a foreign hive. The queenright bees, form all 4 localities were found to have 9HDA as the most abundant of the 5 fatty acids measured and all localities had small percentages of 9ODA in their mandibular gland secretions. This resulted in relatively high queenright 9ODA:10HDA and 9HDA:10HDAA ratios. Despite this the percentage of bees with undeveloped ovaries was consistent with their queenright status. The mean values of these 2 ratios were significantly higher in the bees from East London and Cradock than those from Port Elizabeth. Steynsburg's bees were intermediate in this regard. Upon queen loss, the bees from all 4 localities had an increase in the percentage of 9ODA but the other compound changes in varying ways. East London's bees were the only ones not to become significantly more queen-like after queen loss. After 14 days without a queen, the mean values of these 2 ratios were much higher in the bees from Port Elizabeth than those from the other localities. Certain individuals from Port Elizabeth had values of these ratios that exceeded those found in A. m. capensis queens. Port Elizabeth was the only locality to display any surrogate queens and exhibited the highest increase in the number of bees with partially or fully developed ovaries. While certain individuals from the other localities had values of these ratios that exceeded these values reported in A. m. scutellata queens, Steynsburg's bees were the only ones that did increase in in terms of the number of bees with developed ovaries subsequent. The bees from Steynsburg were shown to suppress the mandibular gland and ovarial development of drifters from Port Elizabeth while bees from East London did not.
- Full Text:
- Date Issued: 2001
- Authors: Reece, Sacha Louise
- Date: 2001
- Subjects: Honeybee -- South Africa -- Eastern Cape , Honeybee -- Behavior , Honeybee -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5729 , http://hdl.handle.net/10962/d1005415 , Honeybee -- South Africa -- Eastern Cape , Honeybee -- Behavior , Honeybee -- Physiology
- Description: The Eastern Cape is an area in which Apis mellifera capensis, A. m. scutellata and their hybrid are known to naturally occur. I investigated the mandibular gland profiles and ovarial development of queenright workers from 4 localities. Their queens were then removed to determine how these aspects changed upon queen loss. In addition, drifted bees were analysed in the same way to determine how these factors changed once they had gained entry to a foreign hive. The queenright bees, form all 4 localities were found to have 9HDA as the most abundant of the 5 fatty acids measured and all localities had small percentages of 9ODA in their mandibular gland secretions. This resulted in relatively high queenright 9ODA:10HDA and 9HDA:10HDAA ratios. Despite this the percentage of bees with undeveloped ovaries was consistent with their queenright status. The mean values of these 2 ratios were significantly higher in the bees from East London and Cradock than those from Port Elizabeth. Steynsburg's bees were intermediate in this regard. Upon queen loss, the bees from all 4 localities had an increase in the percentage of 9ODA but the other compound changes in varying ways. East London's bees were the only ones not to become significantly more queen-like after queen loss. After 14 days without a queen, the mean values of these 2 ratios were much higher in the bees from Port Elizabeth than those from the other localities. Certain individuals from Port Elizabeth had values of these ratios that exceeded those found in A. m. capensis queens. Port Elizabeth was the only locality to display any surrogate queens and exhibited the highest increase in the number of bees with partially or fully developed ovaries. While certain individuals from the other localities had values of these ratios that exceeded these values reported in A. m. scutellata queens, Steynsburg's bees were the only ones that did increase in in terms of the number of bees with developed ovaries subsequent. The bees from Steynsburg were shown to suppress the mandibular gland and ovarial development of drifters from Port Elizabeth while bees from East London did not.
- Full Text:
- Date Issued: 2001
Selected physiological and perceptual responses of batsmen during a simulated one day international century : impact on performance
- Authors: Pote, Lee
- Date: 2013 , 2013-04-02
- Subjects: Cricket -- Batting , Sports -- Physiological aspects , Sports -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5097 , http://hdl.handle.net/10962/d1001650
- Description: Background: Very few studies have examined the demands of prolonged batting on physical, psychophysical and performance responses. Objective: The purpose of this study was therefore to determine the physiological and perceptual responses of batsmen scoring a simulated One Day International century. Furthermore, the impact that these responses had on batting performance were also measured. Methods: Seventeen male cricketers currently playing for Rhodes University or the country districts side, performed a simulated bating innings (BATEX©), typical of scoring a One Day international century. The BATEX© protocol consisted of six, five over stages (21 minutes each), with each stage matched to a specific phase of play where batsmen were encouraged to bat with the mindset of that phase. During stages one, three and five players ran at a “self-selected cruise pace” whereas during stages two, four and six players were required to run at maximum speed. At set intervals, selected physiological, perceptual and performance measures were recorded. Results: Most physiological responses increased and decreased accordingly with the low and high intensity stages with the exception of respiratory exchange ratio and core temperature responses. Mean physiological responses however, showed a progressive rise over time. Central ratings of perceived exertion increased as a function of intensity and duration. Sprint times got slower as the protocol progressed, while accuracy (impact accuracy) improved significantly (p<0.05) after stage one and then stabilised for the remainder of the protocol. Conclusion: The simulated batting protocol significantly impacted the physiological and perceptual responses over time. This was due to both the intensity and the duration of the work-bout. Furthermore, the increased physiological load placed on the batsmen significantly impacted the physical performance of the batsmen. An increase in sprint times (players getting slower) towards the end of the protocol may indicate the presence of physical fatigue. This physical fatigue did not however seem to impact the batsmen cognitively as accuracy improved after the first stage and then remained constant over time.
- Full Text:
- Date Issued: 2013
- Authors: Pote, Lee
- Date: 2013 , 2013-04-02
- Subjects: Cricket -- Batting , Sports -- Physiological aspects , Sports -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5097 , http://hdl.handle.net/10962/d1001650
- Description: Background: Very few studies have examined the demands of prolonged batting on physical, psychophysical and performance responses. Objective: The purpose of this study was therefore to determine the physiological and perceptual responses of batsmen scoring a simulated One Day International century. Furthermore, the impact that these responses had on batting performance were also measured. Methods: Seventeen male cricketers currently playing for Rhodes University or the country districts side, performed a simulated bating innings (BATEX©), typical of scoring a One Day international century. The BATEX© protocol consisted of six, five over stages (21 minutes each), with each stage matched to a specific phase of play where batsmen were encouraged to bat with the mindset of that phase. During stages one, three and five players ran at a “self-selected cruise pace” whereas during stages two, four and six players were required to run at maximum speed. At set intervals, selected physiological, perceptual and performance measures were recorded. Results: Most physiological responses increased and decreased accordingly with the low and high intensity stages with the exception of respiratory exchange ratio and core temperature responses. Mean physiological responses however, showed a progressive rise over time. Central ratings of perceived exertion increased as a function of intensity and duration. Sprint times got slower as the protocol progressed, while accuracy (impact accuracy) improved significantly (p<0.05) after stage one and then stabilised for the remainder of the protocol. Conclusion: The simulated batting protocol significantly impacted the physiological and perceptual responses over time. This was due to both the intensity and the duration of the work-bout. Furthermore, the increased physiological load placed on the batsmen significantly impacted the physical performance of the batsmen. An increase in sprint times (players getting slower) towards the end of the protocol may indicate the presence of physical fatigue. This physical fatigue did not however seem to impact the batsmen cognitively as accuracy improved after the first stage and then remained constant over time.
- Full Text:
- Date Issued: 2013
Research portfolio : environmental education
- Authors: Le Roux, Kim
- Date: 1999
- Subjects: Environmental education -- South Africa , Environmental education -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1738 , http://hdl.handle.net/10962/d1003622
- Full Text:
- Date Issued: 1999
- Authors: Le Roux, Kim
- Date: 1999
- Subjects: Environmental education -- South Africa , Environmental education -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1738 , http://hdl.handle.net/10962/d1003622
- Full Text:
- Date Issued: 1999
A q-metholological approach to audience reception of public awareness messages on sexual violence
- Authors: Bennie, Rachel
- Date: 2020
- Subjects: Psychology -- Research -- Methodology , Psychology -- Research , Communication in social action -- South Africa , Psychology -- Research -- South Africa , Women -- Violence against -- South Africa , Women -- Violence against -- South Africa -- Prevention
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140805 , vital:37920
- Description: Public awareness poster campaigns are an often-used method for raising awareness about, and engaging audiences on the topic of rape and other forms of sexual violence (Potter, 2012). However, poster campaigns, as social artefacts, operate in a public arena in which numerous discourses about a phenomenon are produced, reproduced and interact with each other, with sometimes unintended/unanticipated discursive consequences (Böhmke, Bennie, Minnie, Moore, Pilusa & Pollock, 2015). How messages aimed at raising awareness of sexual violence are framed has the potential to reproduce dominant social narratives and gendered subject positions in ways that reinforce notions of men as active sexual agents and potential perpetrators, and women as sexually passive and potential victims (Gavey, 2005). Other approaches, such as bystander intervention, seek to move away from a focus on victims and perpetrators to emphasise the role that community members can play in risk detection, safety promotion and the prevention of sexual violence (McMahon & Banyard, 2012). Since a range of possible messages about sexual violence can be communicated through poster campaigns, it is important to critically examine the content and orientation of campaign material. This study focused on intended audience views regarding messages about sexual violence contained in anti-sexual violence poster materials. The purpose was to collaborate with a selected audience to better understand which messages are effective and which strategies of communication are perceived to be less so. Through the use of Q-methodology, volunteer participants were invited to express their opinions in relation to messages about sexual violence from a range of posters from several international campaigns. The analysis focused on uncovering the discursive subject positions that participants’ express in their attitudinal responses to the poster messages, providing not only a description of these positions, but also illustrating the level of resonance that the poster messages may find with intended audiences. The aim of the study is to potentially inform the development of more focused campaign material, tailored to the specific context from which participants were drawn. Analysis shows clear patterns of audience resistance towards stereotypical representations of sexual violence and messages that are geared towards the simple prohibition of behaviours. The findings highlight the need for the development of alternative strategies of engagement that focus on specific engagement with understandings of sexual violence in the context of intimate and/or acquaintance relationships and which are aimed at inviting audiences to take up a position in relation to sexual violence phenomena that troubles the reproduction of received notions of gendered subjectivities and (hetero) sexuality
- Full Text:
- Date Issued: 2020
- Authors: Bennie, Rachel
- Date: 2020
- Subjects: Psychology -- Research -- Methodology , Psychology -- Research , Communication in social action -- South Africa , Psychology -- Research -- South Africa , Women -- Violence against -- South Africa , Women -- Violence against -- South Africa -- Prevention
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140805 , vital:37920
- Description: Public awareness poster campaigns are an often-used method for raising awareness about, and engaging audiences on the topic of rape and other forms of sexual violence (Potter, 2012). However, poster campaigns, as social artefacts, operate in a public arena in which numerous discourses about a phenomenon are produced, reproduced and interact with each other, with sometimes unintended/unanticipated discursive consequences (Böhmke, Bennie, Minnie, Moore, Pilusa & Pollock, 2015). How messages aimed at raising awareness of sexual violence are framed has the potential to reproduce dominant social narratives and gendered subject positions in ways that reinforce notions of men as active sexual agents and potential perpetrators, and women as sexually passive and potential victims (Gavey, 2005). Other approaches, such as bystander intervention, seek to move away from a focus on victims and perpetrators to emphasise the role that community members can play in risk detection, safety promotion and the prevention of sexual violence (McMahon & Banyard, 2012). Since a range of possible messages about sexual violence can be communicated through poster campaigns, it is important to critically examine the content and orientation of campaign material. This study focused on intended audience views regarding messages about sexual violence contained in anti-sexual violence poster materials. The purpose was to collaborate with a selected audience to better understand which messages are effective and which strategies of communication are perceived to be less so. Through the use of Q-methodology, volunteer participants were invited to express their opinions in relation to messages about sexual violence from a range of posters from several international campaigns. The analysis focused on uncovering the discursive subject positions that participants’ express in their attitudinal responses to the poster messages, providing not only a description of these positions, but also illustrating the level of resonance that the poster messages may find with intended audiences. The aim of the study is to potentially inform the development of more focused campaign material, tailored to the specific context from which participants were drawn. Analysis shows clear patterns of audience resistance towards stereotypical representations of sexual violence and messages that are geared towards the simple prohibition of behaviours. The findings highlight the need for the development of alternative strategies of engagement that focus on specific engagement with understandings of sexual violence in the context of intimate and/or acquaintance relationships and which are aimed at inviting audiences to take up a position in relation to sexual violence phenomena that troubles the reproduction of received notions of gendered subjectivities and (hetero) sexuality
- Full Text:
- Date Issued: 2020
An investigation into the use of visualisation processes as a teaching strategy to enhance number sense
- Authors: Griqua, Ronald Max
- Date: 2020
- Subjects: Mathematics -- Study and teaching -- South Africa , Mathematics -- Study and teaching -- Psychological aspects , Visualization , Number concept , RUMEP (Rhodes University Mathematics Education Project)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/147226 , vital:38606
- Description: The literature agrees that in order to improve learning outcomes, instruction in classrooms should be improved first. Mathematics educationists therefore advocate that schools should make extensive and deep efforts to rethink their instructional programmes. Research furthermore suggests that increasingly, indicators on school performance and teaching reveal largely unacknowledged problematic teaching of mathematics in the great majority of South African schools. This research study is therefore a contribution towards rethinking the teaching strategies within mathematics classrooms. The study examined the use of visualisation processes in order to understand how these interact with the pedagogy of selected mathematics teachers when they teach number sense after participating in an intervention programme. This study argues that the effective use of visualisation processes enhanced the teaching of number sense. The research study was framed as a case study that was grounded within the interpretive paradigm. The study was located in classrooms where the participating teachers promoted active learning after taking part in an intervention programme. A constructivist theoretical underpinning was therefore adopted. At the heart of the study was the Visualisation Intervention Programme (VIP), which involved seven Rhodes University Mathematics Education Project (RUMEP) teachers within the John Taolo Gaetsewe District of the Northern Cape Province. The content of the VIP was informed by initially working with five teachers of well-resourced schools within the Northern Cape who made interesting use of visualisation processes and manipulatives to teach number sense. With the assistance of these five teachers, the VIP was then implemented by seven selected RUMEP teachers to investigate the role of visualisation processes in the teaching of number sense understandings. The study employed a mixed method approach. Qualitative data was collected through observations and interviews, while quantitative data was collected with a series of pre- and post-tests. The analysis of the findings of this research study revealed that the effective use of visualisation processes was instrumental in enhancing the teaching of number sense understandings. Furthermore, the use of visualisation processes by the selected teachers fostered independent thought and conceptual understanding of number sense topics on the part of their learners.
- Full Text:
- Date Issued: 2020
- Authors: Griqua, Ronald Max
- Date: 2020
- Subjects: Mathematics -- Study and teaching -- South Africa , Mathematics -- Study and teaching -- Psychological aspects , Visualization , Number concept , RUMEP (Rhodes University Mathematics Education Project)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/147226 , vital:38606
- Description: The literature agrees that in order to improve learning outcomes, instruction in classrooms should be improved first. Mathematics educationists therefore advocate that schools should make extensive and deep efforts to rethink their instructional programmes. Research furthermore suggests that increasingly, indicators on school performance and teaching reveal largely unacknowledged problematic teaching of mathematics in the great majority of South African schools. This research study is therefore a contribution towards rethinking the teaching strategies within mathematics classrooms. The study examined the use of visualisation processes in order to understand how these interact with the pedagogy of selected mathematics teachers when they teach number sense after participating in an intervention programme. This study argues that the effective use of visualisation processes enhanced the teaching of number sense. The research study was framed as a case study that was grounded within the interpretive paradigm. The study was located in classrooms where the participating teachers promoted active learning after taking part in an intervention programme. A constructivist theoretical underpinning was therefore adopted. At the heart of the study was the Visualisation Intervention Programme (VIP), which involved seven Rhodes University Mathematics Education Project (RUMEP) teachers within the John Taolo Gaetsewe District of the Northern Cape Province. The content of the VIP was informed by initially working with five teachers of well-resourced schools within the Northern Cape who made interesting use of visualisation processes and manipulatives to teach number sense. With the assistance of these five teachers, the VIP was then implemented by seven selected RUMEP teachers to investigate the role of visualisation processes in the teaching of number sense understandings. The study employed a mixed method approach. Qualitative data was collected through observations and interviews, while quantitative data was collected with a series of pre- and post-tests. The analysis of the findings of this research study revealed that the effective use of visualisation processes was instrumental in enhancing the teaching of number sense understandings. Furthermore, the use of visualisation processes by the selected teachers fostered independent thought and conceptual understanding of number sense topics on the part of their learners.
- Full Text:
- Date Issued: 2020
An organisation development intervention in a secondary school in the Erongo region of Namibia
- Authors: Steenkamp, Angeline Anna
- Date: 2011
- Subjects: School management and organization -- Namibia -- Erongo Organizational change -- Namibia -- Erongo Curriculum planning -- Namibia -- Erongo
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1683 , http://hdl.handle.net/10962/d1003566
- Description: The challenge for Namibia is to translate Vision 2030 into realistic and implementable programmes and to develop and adopt a set of interventions which will raise the quality of education. The quality of education currently on offer varies from school to school and, indeed, from class to class (Namibia. MoE, 2006, p. 1). The National Standards and Performance Indicators (ETSIP, 2006) for schools in Namibia and the Education and Training Sector Improvement Programme (ETSIP), have been developed to address the quality of education across the country, and to make provision for school managers to be trained. Organisation Development is a planned change approach which focuses on the change processes of the organisation, by opening up communication, decreasing internal destructiveness – such as win-lose conflicts – and by increasing creativity in problem solving. It is based on the values and assumptions about people and their organisations. OD promotes interdependence and interconnectedness, involvement in problem solving and decision making. OD is a process for teaching people how to solve problems, take advantage of opportunities, and learn how to do better over time. OD was introduced to Evergreen Senior Secondary School in the form of a Survey Data Feedback (SDF) where data was collected, analysed and fed back to the participants. The case study involved 20 staff members made up of the principal, two head of departments and 17 teachers. Formal and focus-group interviews, as well as observation, were used to collect data. What was derived from the data was that the OD approach was something new to the participants, and served as an eye-opener. Further, it became evident from the data that participants had high hopes that OD would bring about immediate visible changes regarding the operation of their organisation. It is essential to remind participants that OD is a long-term change process, and not a “quick fix”.
- Full Text:
- Date Issued: 2011
- Authors: Steenkamp, Angeline Anna
- Date: 2011
- Subjects: School management and organization -- Namibia -- Erongo Organizational change -- Namibia -- Erongo Curriculum planning -- Namibia -- Erongo
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1683 , http://hdl.handle.net/10962/d1003566
- Description: The challenge for Namibia is to translate Vision 2030 into realistic and implementable programmes and to develop and adopt a set of interventions which will raise the quality of education. The quality of education currently on offer varies from school to school and, indeed, from class to class (Namibia. MoE, 2006, p. 1). The National Standards and Performance Indicators (ETSIP, 2006) for schools in Namibia and the Education and Training Sector Improvement Programme (ETSIP), have been developed to address the quality of education across the country, and to make provision for school managers to be trained. Organisation Development is a planned change approach which focuses on the change processes of the organisation, by opening up communication, decreasing internal destructiveness – such as win-lose conflicts – and by increasing creativity in problem solving. It is based on the values and assumptions about people and their organisations. OD promotes interdependence and interconnectedness, involvement in problem solving and decision making. OD is a process for teaching people how to solve problems, take advantage of opportunities, and learn how to do better over time. OD was introduced to Evergreen Senior Secondary School in the form of a Survey Data Feedback (SDF) where data was collected, analysed and fed back to the participants. The case study involved 20 staff members made up of the principal, two head of departments and 17 teachers. Formal and focus-group interviews, as well as observation, were used to collect data. What was derived from the data was that the OD approach was something new to the participants, and served as an eye-opener. Further, it became evident from the data that participants had high hopes that OD would bring about immediate visible changes regarding the operation of their organisation. It is essential to remind participants that OD is a long-term change process, and not a “quick fix”.
- Full Text:
- Date Issued: 2011
The sedimentology and palaeoenvironmental significance of vlei sediments on the Winterberg range, South Africa
- Authors: Dewey, Felicity Joy
- Date: 1989
- Subjects: Geology, Stratigraphic -- Holocene Sedimentology Sediments (Geology) -- South Africa -- Eastern Cape -- Winterberg range Geology, Stratigraphic -- Pleistocene Paleoecology -- South Africa -- Eastern Cape -- Winterberg range
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4797 , http://hdl.handle.net/10962/d1001897
- Description: Palaeoenvironmental reconstruction of the late Pleistocene and Holocene geological periods for central and southern Africa has been hampered by the erratic distribution of suitable sites, incomplete and inaccurately dated sequences and the limited nature of published data. One geomorphological feature which has supplied valuable evidence for fluctuations in past environmental conditions, is the vlei or dambo. The type-site of these waterlogged features is in south central Africa, but similar features have been described on other continents. The clastic and organic sediments contained within these features are affected by, and therefore reflect to some degree, the environment under which they were formed. The characteristics of the sediments supply information as to their transport and mechanisms of deposition. From these processes, the environmental conditions at the time of vlei formation can be inferred. The environmental history of the Eastern Cape region has been considerably neglected, and is far less well understood than other countries such as Malawi, Zambia and Zimbabwe. A study site in the Winterberg Range (Eastern Cape) was selected which permitted the comparison of two vleis, the objective being to establish an accurate late Pleistocene sediment chronology for the entire plateau area. Radiocarbon dates from organic layers indicate that these sediments span the last 12 000 years BP, suggesting that organic accumulation at this site began at roughly the same time as at sites further afield. The vlei sediments are analysed in terms of their morphology, particle slze distribution, and other physical and chemical characteristics. These data facilitate the construction of detailed stratigraphic diagrams and a chronological summary of sediment accumulation, from which the period and governing processes of vlei development under changing environments may be described. It is found that the Winterberg vleis contain sediments which respond to changes in the prevailing environment. This makes these sediments useful indices from which to trace such changes during the late Pleistocene and Holocene times. These features are found to be similar in many respects to those described elsewhere in Southern Africa. The study attempts to provide greater understanding of contemporary vlei processes and emphasises the necessity of their preservation, as finite and valuable resources, by future generations
- Full Text:
- Date Issued: 1989
- Authors: Dewey, Felicity Joy
- Date: 1989
- Subjects: Geology, Stratigraphic -- Holocene Sedimentology Sediments (Geology) -- South Africa -- Eastern Cape -- Winterberg range Geology, Stratigraphic -- Pleistocene Paleoecology -- South Africa -- Eastern Cape -- Winterberg range
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4797 , http://hdl.handle.net/10962/d1001897
- Description: Palaeoenvironmental reconstruction of the late Pleistocene and Holocene geological periods for central and southern Africa has been hampered by the erratic distribution of suitable sites, incomplete and inaccurately dated sequences and the limited nature of published data. One geomorphological feature which has supplied valuable evidence for fluctuations in past environmental conditions, is the vlei or dambo. The type-site of these waterlogged features is in south central Africa, but similar features have been described on other continents. The clastic and organic sediments contained within these features are affected by, and therefore reflect to some degree, the environment under which they were formed. The characteristics of the sediments supply information as to their transport and mechanisms of deposition. From these processes, the environmental conditions at the time of vlei formation can be inferred. The environmental history of the Eastern Cape region has been considerably neglected, and is far less well understood than other countries such as Malawi, Zambia and Zimbabwe. A study site in the Winterberg Range (Eastern Cape) was selected which permitted the comparison of two vleis, the objective being to establish an accurate late Pleistocene sediment chronology for the entire plateau area. Radiocarbon dates from organic layers indicate that these sediments span the last 12 000 years BP, suggesting that organic accumulation at this site began at roughly the same time as at sites further afield. The vlei sediments are analysed in terms of their morphology, particle slze distribution, and other physical and chemical characteristics. These data facilitate the construction of detailed stratigraphic diagrams and a chronological summary of sediment accumulation, from which the period and governing processes of vlei development under changing environments may be described. It is found that the Winterberg vleis contain sediments which respond to changes in the prevailing environment. This makes these sediments useful indices from which to trace such changes during the late Pleistocene and Holocene times. These features are found to be similar in many respects to those described elsewhere in Southern Africa. The study attempts to provide greater understanding of contemporary vlei processes and emphasises the necessity of their preservation, as finite and valuable resources, by future generations
- Full Text:
- Date Issued: 1989
A study of fuzzy sets and systems with applications to group theory and decision making
- Authors: Gideon, Frednard
- Date: 2006
- Subjects: Fuzzy sets , Fuzzy systems , Abelian groups , Decision making
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5417 , http://hdl.handle.net/10962/d1005231 , Fuzzy sets , Fuzzy systems , Abelian groups , Decision making
- Description: In this study we apply the knowledge of fuzzy sets to group structures and also to decision-making implications. We study fuzzy subgroups of finite abelian groups. We set G = Z[subscript p[superscript n]] + Z[subscript q[superscript m]]. The classification of fuzzy subgroups of G using equivalence classes is introduced. First, we present equivalence relations on fuzzy subsets of X, and then extend it to the study of equivalence relations of fuzzy subgroups of a group G. This is then followed by the notion of flags and keychains projected as tools for enumerating fuzzy subgroups of G. In addition to this, we use linear ordering of the lattice of subgroups to characterize the maximal chains of G. Then we narrow the gap between group theory and decision-making using relations. Finally, a theory of the decision-making process in a fuzzy environment leads to a fuzzy version of capital budgeting. We define the goal, constraints and decision and show how they conflict with each other using membership function implications. We establish sets of intervals for projecting decision boundaries in general. We use the knowledge of triangular fuzzy numbers which are restricted field of fuzzy logic to evaluate investment projections.
- Full Text:
- Date Issued: 2006
- Authors: Gideon, Frednard
- Date: 2006
- Subjects: Fuzzy sets , Fuzzy systems , Abelian groups , Decision making
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5417 , http://hdl.handle.net/10962/d1005231 , Fuzzy sets , Fuzzy systems , Abelian groups , Decision making
- Description: In this study we apply the knowledge of fuzzy sets to group structures and also to decision-making implications. We study fuzzy subgroups of finite abelian groups. We set G = Z[subscript p[superscript n]] + Z[subscript q[superscript m]]. The classification of fuzzy subgroups of G using equivalence classes is introduced. First, we present equivalence relations on fuzzy subsets of X, and then extend it to the study of equivalence relations of fuzzy subgroups of a group G. This is then followed by the notion of flags and keychains projected as tools for enumerating fuzzy subgroups of G. In addition to this, we use linear ordering of the lattice of subgroups to characterize the maximal chains of G. Then we narrow the gap between group theory and decision-making using relations. Finally, a theory of the decision-making process in a fuzzy environment leads to a fuzzy version of capital budgeting. We define the goal, constraints and decision and show how they conflict with each other using membership function implications. We establish sets of intervals for projecting decision boundaries in general. We use the knowledge of triangular fuzzy numbers which are restricted field of fuzzy logic to evaluate investment projections.
- Full Text:
- Date Issued: 2006
Initiating biological control for Nymphaea mexicana zuccarini (Nymphaeaceae) in South Africa
- Authors: Reid, Megan
- Date: 2020
- Subjects: Nymphaea mexicana zuccarini -- Biological control -- South Africa , Nymphaeaceae -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144510 , vital:38352
- Description: Nymphaea mexicana Zuccarini (Nymphaeaceae) is an aquatic plant originating from south-eastern USA that is becoming increasingly invasive in South Africa as other invasive aquatic plants are being managed successfully through biological control. Mechanical and chemical control of aquatic weeds is expensive, damaging to the environment, and only effective in the short term, so biological control is more desirable as a management strategy for N. mexicana. The biological control of invasive alien plants requires that agents are host specific so that non-target risks are mitigated. For success to be achieved, it is important to ensure that the genetic structure of invasive populations is clarified so that agents can be collected from populations in the native range that match genetically to populations in the invasive range. This is especially important in cases where the morphology of invasive alien plants does not reflect genetic differences between populations. A previous study of the genetic structure of the invasive populations of N. mexicana in South Africa suggests the presence of hybrid forms of the plant in South Africa, with only one of these populations matching with samples from the native range. However, the study only used samples from two sites in the native range using amplified fragment length polymorphisms (AFLPs), so it was necessary to conduct further genetic analyses using samples from more sites in the native range. Hence, the first aim of this study was to develop a better understanding of the genetic structure of N. mexicana populations in the native and invaded range. Genetic samples were collected from sites in the native range during field surveys for potential biological control agents, and inter-simple sequence repeats (ISSRs) were used to compare the genetic structure of invasive and native populations of N. mexicana in South Africa. The results from these analyses suggest that seven of the 14 investigated invasive populations of N. mexicana in South Africa are genetically similar to populations in the native range, while the remaining seven populations are likely to be hybrid forms of the plant. This knowledge will be useful to target populations for biological control and highlights the need for further genetic analyses to determine the parentage of these hybrids so that biological control efforts are more likely to be successful. The initiation of a biological control programme requires that a series of steps are taken in order to maximise the likelihood that this form of intervention will be successful. The first few steps include: identification of the target weed and its genetic structure; exploration in the native range for potential biological control agents; and prioritisation of these agents based on factors such as climatic and genetic compatibility, feeding damage, abundance, and likely host range. Hence, the second aim of this study was to conduct surveys for potential biological control agents in the native range of N. mexicana, and to prioritise these agents. Field surveys were conducted between August and October in 2018 at 17 sites in Florida, Louisiana, and Texas, USA. Sites were selected based on climatic similarity of native sites compared to invasive sites by use of MaxEnt modelling. Native N. mexicana plants were searched for natural enemies, and these were prioritised based on feeding damage, abundance, incidence, and observations of field host range. Two species were prioritised: Bagous americanus LeConte (Coleoptera: Curculionidae) and Megamelus toddi Beamer (Hemiptera: Delphacidae). These species will be imported into quarantine facilities at Rhodes University for host specificity tests to be conducted. Understanding the factors that contribute to the successful establishment of biological control agents is important to improve the efficiency and reduce the costs incurred during the initiation of biological control programmes. Acquiring knowledge of the factors that predict the efficacy of biological control agents is similarly important, and these factors are discussed in the last chapter of this study. The challenges of the biological control of hybrids are also considered, and recommendations are made for the control of N. mexicana and other plants in South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Reid, Megan
- Date: 2020
- Subjects: Nymphaea mexicana zuccarini -- Biological control -- South Africa , Nymphaeaceae -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144510 , vital:38352
- Description: Nymphaea mexicana Zuccarini (Nymphaeaceae) is an aquatic plant originating from south-eastern USA that is becoming increasingly invasive in South Africa as other invasive aquatic plants are being managed successfully through biological control. Mechanical and chemical control of aquatic weeds is expensive, damaging to the environment, and only effective in the short term, so biological control is more desirable as a management strategy for N. mexicana. The biological control of invasive alien plants requires that agents are host specific so that non-target risks are mitigated. For success to be achieved, it is important to ensure that the genetic structure of invasive populations is clarified so that agents can be collected from populations in the native range that match genetically to populations in the invasive range. This is especially important in cases where the morphology of invasive alien plants does not reflect genetic differences between populations. A previous study of the genetic structure of the invasive populations of N. mexicana in South Africa suggests the presence of hybrid forms of the plant in South Africa, with only one of these populations matching with samples from the native range. However, the study only used samples from two sites in the native range using amplified fragment length polymorphisms (AFLPs), so it was necessary to conduct further genetic analyses using samples from more sites in the native range. Hence, the first aim of this study was to develop a better understanding of the genetic structure of N. mexicana populations in the native and invaded range. Genetic samples were collected from sites in the native range during field surveys for potential biological control agents, and inter-simple sequence repeats (ISSRs) were used to compare the genetic structure of invasive and native populations of N. mexicana in South Africa. The results from these analyses suggest that seven of the 14 investigated invasive populations of N. mexicana in South Africa are genetically similar to populations in the native range, while the remaining seven populations are likely to be hybrid forms of the plant. This knowledge will be useful to target populations for biological control and highlights the need for further genetic analyses to determine the parentage of these hybrids so that biological control efforts are more likely to be successful. The initiation of a biological control programme requires that a series of steps are taken in order to maximise the likelihood that this form of intervention will be successful. The first few steps include: identification of the target weed and its genetic structure; exploration in the native range for potential biological control agents; and prioritisation of these agents based on factors such as climatic and genetic compatibility, feeding damage, abundance, and likely host range. Hence, the second aim of this study was to conduct surveys for potential biological control agents in the native range of N. mexicana, and to prioritise these agents. Field surveys were conducted between August and October in 2018 at 17 sites in Florida, Louisiana, and Texas, USA. Sites were selected based on climatic similarity of native sites compared to invasive sites by use of MaxEnt modelling. Native N. mexicana plants were searched for natural enemies, and these were prioritised based on feeding damage, abundance, incidence, and observations of field host range. Two species were prioritised: Bagous americanus LeConte (Coleoptera: Curculionidae) and Megamelus toddi Beamer (Hemiptera: Delphacidae). These species will be imported into quarantine facilities at Rhodes University for host specificity tests to be conducted. Understanding the factors that contribute to the successful establishment of biological control agents is important to improve the efficiency and reduce the costs incurred during the initiation of biological control programmes. Acquiring knowledge of the factors that predict the efficacy of biological control agents is similarly important, and these factors are discussed in the last chapter of this study. The challenges of the biological control of hybrids are also considered, and recommendations are made for the control of N. mexicana and other plants in South Africa.
- Full Text:
- Date Issued: 2020
Marie Curie : a psychobiography
- Authors: Roets, Elmeret
- Date: 2016
- Subjects: Curie, Marie -- 1867-1934 -- Psychology , Women chemists -- Poland -- Biography , Scientists -- Biography
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3269 , http://hdl.handle.net/10962/d1020326
- Description: While researchers debate the value of psychobiographical research, interest in this area is growing on a national and international basis. Every year, the number of psychobiographical studies at universities in South Africa is growing. Psychobiographical research is qualitative research that utilises psychological theory to explore and describe the lives of extraordinary individuals. The primary aim of this psychobiography was to examine the life of Marie Curie (1867–1934) by employing developmental psychologist and psychoanalyst Erik Erikson’s (1959) theory of psychosocial personality development. Marie Curie was chosen as the research subject because of the researcher’s personal interest and the subject’s prominence as a female scientist. She was a Polish-born and naturalised French scientist who conducted pioneering research on radioactivity. Marie Curie’s ground-breaking discoveries changed the way scientists think about matter and energy and introduced a new era in medical knowledge and the treatment of disease. Her life exemplifies a love of science, commitment, and perseverance. Data were collected from several primary and secondary sources on Marie Curie’s life. The researcher developed a data-collection and analysis matrix to facilitate the systematic collection of data and analysis according to Erikson’s stage theory of psychosocial personality development. This psychobiography suggests that unresolved infantile and early childhood crises gave rise to personality traits that eventually contributed to Curie’s extraordinariness. In the case of Curie, personality traits that are often regarded as atypical or malignant, ironically encouraged perseverance, creativity, and productivity. This study complements the psychobiographical studies done in South Africa on extraordinary individuals. It demonstrated the value of psychobiographical research as a teaching instrument, revealed the usefulness of Erikson’s theory, and illustrated the uniqueness of individuals.
- Full Text:
- Date Issued: 2016
- Authors: Roets, Elmeret
- Date: 2016
- Subjects: Curie, Marie -- 1867-1934 -- Psychology , Women chemists -- Poland -- Biography , Scientists -- Biography
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3269 , http://hdl.handle.net/10962/d1020326
- Description: While researchers debate the value of psychobiographical research, interest in this area is growing on a national and international basis. Every year, the number of psychobiographical studies at universities in South Africa is growing. Psychobiographical research is qualitative research that utilises psychological theory to explore and describe the lives of extraordinary individuals. The primary aim of this psychobiography was to examine the life of Marie Curie (1867–1934) by employing developmental psychologist and psychoanalyst Erik Erikson’s (1959) theory of psychosocial personality development. Marie Curie was chosen as the research subject because of the researcher’s personal interest and the subject’s prominence as a female scientist. She was a Polish-born and naturalised French scientist who conducted pioneering research on radioactivity. Marie Curie’s ground-breaking discoveries changed the way scientists think about matter and energy and introduced a new era in medical knowledge and the treatment of disease. Her life exemplifies a love of science, commitment, and perseverance. Data were collected from several primary and secondary sources on Marie Curie’s life. The researcher developed a data-collection and analysis matrix to facilitate the systematic collection of data and analysis according to Erikson’s stage theory of psychosocial personality development. This psychobiography suggests that unresolved infantile and early childhood crises gave rise to personality traits that eventually contributed to Curie’s extraordinariness. In the case of Curie, personality traits that are often regarded as atypical or malignant, ironically encouraged perseverance, creativity, and productivity. This study complements the psychobiographical studies done in South Africa on extraordinary individuals. It demonstrated the value of psychobiographical research as a teaching instrument, revealed the usefulness of Erikson’s theory, and illustrated the uniqueness of individuals.
- Full Text:
- Date Issued: 2016
Molecular and biochemical analysis of the diet of the black rhinoceros
- Authors: Kgopa, Ananias Hodi
- Date: 2009 , 2013-07-15
- Subjects: Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- South Africa -- Eastern Cape -- Analysis , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants , Plant ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4064 , http://hdl.handle.net/10962/d1004721 , Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- South Africa -- Eastern Cape -- Analysis , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants , Plant ecology -- South Africa -- Eastern Cape
- Description: The black rhinoceros, Diceros bicornis, is listed as critically endangered. The black rhinoceros population in the Great Fish River Reserve (GFRR) has increased steadily to a current estimate of one hundred animals since the re-introduction of four animals in 1986. In an effort to contribute to the effective conservation and management of this species, dietary composition was studied in the medium Portulcaria thicket vegetation of the GFRR. This study used a molecular approach to determine the diet of the black rhinoceros of the GFRR by sequencing the ribulose bisphosphate carboxylase large subunit (rbcL) gene in plants and dung. Twenty-three plant species were collected from the reserve, and 802 bp of the rbcL gene were sequenced. These plant sequences were used as a reference database for the identification of plant sequences generated from black rhinoceros dung. Initial studies investigated the amplification, cloning and sequencing of DNA extracted from the dung samples which indicated the viability of the molecular approach. Thereafter, dung generated rbcL DNA was analyzed by GS FLX sequencing. Of the plant sequences identified by comparison to the GenBank database, Carissa bispinosa was the most prevalent. The study further characterized the antioxidant activities and phenolic content of plants eaten by the black rhinoceros using four different assays. Phyllanthus verrucosus, Putterlickia pyracantha, Maytenus capitata, Euclea undulata and Ozoroa mucrunata consistently had high antioxidant activities when assayed against 2,2-azinobis (3-ethyl benzothiazolium-6-sulfonic acid) (ABTSʹ⁺), 2,2-diphenyl-1-picrylhydrazyl (DPPHʹ), and ferric reducing antioxidant potentials (FRAP) and phenolic content when evaluated using the Folin-Ciocalteu assay. The majority of plants investigated showed low antioxidant potentials and low phenolic content. The extent to which antioxidants influenced the browse selection by the black rhinoceros remains inconclusive.
- Full Text:
- Date Issued: 2009
- Authors: Kgopa, Ananias Hodi
- Date: 2009 , 2013-07-15
- Subjects: Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- South Africa -- Eastern Cape -- Analysis , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants , Plant ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4064 , http://hdl.handle.net/10962/d1004721 , Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- South Africa -- Eastern Cape -- Analysis , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants , Plant ecology -- South Africa -- Eastern Cape
- Description: The black rhinoceros, Diceros bicornis, is listed as critically endangered. The black rhinoceros population in the Great Fish River Reserve (GFRR) has increased steadily to a current estimate of one hundred animals since the re-introduction of four animals in 1986. In an effort to contribute to the effective conservation and management of this species, dietary composition was studied in the medium Portulcaria thicket vegetation of the GFRR. This study used a molecular approach to determine the diet of the black rhinoceros of the GFRR by sequencing the ribulose bisphosphate carboxylase large subunit (rbcL) gene in plants and dung. Twenty-three plant species were collected from the reserve, and 802 bp of the rbcL gene were sequenced. These plant sequences were used as a reference database for the identification of plant sequences generated from black rhinoceros dung. Initial studies investigated the amplification, cloning and sequencing of DNA extracted from the dung samples which indicated the viability of the molecular approach. Thereafter, dung generated rbcL DNA was analyzed by GS FLX sequencing. Of the plant sequences identified by comparison to the GenBank database, Carissa bispinosa was the most prevalent. The study further characterized the antioxidant activities and phenolic content of plants eaten by the black rhinoceros using four different assays. Phyllanthus verrucosus, Putterlickia pyracantha, Maytenus capitata, Euclea undulata and Ozoroa mucrunata consistently had high antioxidant activities when assayed against 2,2-azinobis (3-ethyl benzothiazolium-6-sulfonic acid) (ABTSʹ⁺), 2,2-diphenyl-1-picrylhydrazyl (DPPHʹ), and ferric reducing antioxidant potentials (FRAP) and phenolic content when evaluated using the Folin-Ciocalteu assay. The majority of plants investigated showed low antioxidant potentials and low phenolic content. The extent to which antioxidants influenced the browse selection by the black rhinoceros remains inconclusive.
- Full Text:
- Date Issued: 2009
Optimistic science: the effectiveness of economic methodology in achieving objectivity
- Authors: Holl, Ryan
- Date: 2012
- Subjects: Economics -- Methodology , Social epistemology , Knowledge, Theory of -- Science , Objectivity -- Science , Science -- Methodology , Optimism
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1105 , http://hdl.handle.net/10962/d1013393
- Description: This thesis examines the extent to which optimism has a bearing on objectivity in scientific inquiry. It is not, however, a psychological level examination into objectivity. Rather, the discussion focuses on collective attitudes, whether in the form of science or a more general public opinion. In essence, sources of optimism at the fundamental level of scientific inquiry are articulated with a careful attempt to differentiate between attitudes about the subject (methodology) and the object of study. The antithetical thread of optimism versus pessimism is teased out with the use of a joint case study of liberalism and Stalinism. The idea of antithesis, however, is contrasted by the fact that, although mirror image ideologies, these collective attitudes share a common faith in progress (albeit through different social mechanisms). This faith in progress provides the basis for the crux of the thesis as it moves to discuss scientific methodology. There is general agreement on what good science should look like and the possibility of progressive science can be articulated. However, it is also possible to highlight the conditions for degenerative science and to further link this to a degenerative social totality in which democracy and social progress are undermined. Economics is used as a case study and it is argued that dogmatic notions on progress have proved to be a major stumbling block to objectivity in the discipline. Furthermore, the implications on the real world are serious.
- Full Text:
- Date Issued: 2012
- Authors: Holl, Ryan
- Date: 2012
- Subjects: Economics -- Methodology , Social epistemology , Knowledge, Theory of -- Science , Objectivity -- Science , Science -- Methodology , Optimism
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1105 , http://hdl.handle.net/10962/d1013393
- Description: This thesis examines the extent to which optimism has a bearing on objectivity in scientific inquiry. It is not, however, a psychological level examination into objectivity. Rather, the discussion focuses on collective attitudes, whether in the form of science or a more general public opinion. In essence, sources of optimism at the fundamental level of scientific inquiry are articulated with a careful attempt to differentiate between attitudes about the subject (methodology) and the object of study. The antithetical thread of optimism versus pessimism is teased out with the use of a joint case study of liberalism and Stalinism. The idea of antithesis, however, is contrasted by the fact that, although mirror image ideologies, these collective attitudes share a common faith in progress (albeit through different social mechanisms). This faith in progress provides the basis for the crux of the thesis as it moves to discuss scientific methodology. There is general agreement on what good science should look like and the possibility of progressive science can be articulated. However, it is also possible to highlight the conditions for degenerative science and to further link this to a degenerative social totality in which democracy and social progress are undermined. Economics is used as a case study and it is argued that dogmatic notions on progress have proved to be a major stumbling block to objectivity in the discipline. Furthermore, the implications on the real world are serious.
- Full Text:
- Date Issued: 2012
The evaluation of Phenrica sp.2 (Coleoptera: Chrysomelidae: Alticinae), as a possible biological control agent for Madeira vine, Anredera cordifolia (Ten.) Steenis in South Africa
- Authors: Van der Westhuizen, Liamé
- Date: 2006
- Subjects: Weeds -- Biological control -- South Africa , Biological pest control agents -- South Africa , Invasive plants -- Biological control -- South Africa , Chrysomelidae , Beetles , Flea beetles , Anredera cordifolia -- Biological control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5689 , http://hdl.handle.net/10962/d1005375 , Weeds -- Biological control -- South Africa , Biological pest control agents -- South Africa , Invasive plants -- Biological control -- South Africa , Chrysomelidae , Beetles , Flea beetles , Anredera cordifolia -- Biological control
- Description: Anredera cordifolia (Basellaceae), Madeira vine, is a perennial, semi- succulent climber native from Paraguay to southern Brazil and northern Argentina. It has a history of weediness and difficulty of control once established. In South Africa Madeira vine has a wide range and distribution with altitudes ranging from 10-1800m above sea level. Described as a transformer species, its sheer weight is capable of breaking branches off trees, causing the potential collapse of forest canopies. Chemical and mechanical control methods are expensive, labour intensive and may provide only temporary relief. A biological control programme was therefore initiated in 2003. Cf Phenrica sp. 2 (Coleoptera: Chrysomelidae: Alticinae), was field collected from A. cordifolia in Brazil, SSW of Cascavel in the Paraná Province during a survey in November 2003. Eggs are laid in groups of 16 with the average fertility rate being 89%. After going though three larval instars, the larvae pupate in the soil with the adults eclosing after a period of 17 days. The total developmental time for a generation from egg to egg ranges between 7-8 weeks. Biological traits that favour the flea beetle as a possible biological control agent include long-lived adults (up to 5 months) and multiple generations during the summer period. Both adults and larvae feed extensively on leaves and stems and although developmental rates will slow down during the winter period, no indication of a definite diapause was found under the prevailing laboratory conditions. After completing the larval no-choice trials with twenty-six plant species from 14 plant families Phenrica sp. 2 proved to be adequately host specific, as larval development was only supported by 3 Basellaceae species (including the control A. cordifolia) and one Portulacaceae species. All of these are introduced species in South Africa. The only indigenous Basella species could not be tested as it has a very marginal distribution, and because it’s inconspicuous nature, it is seldom seen or collected. Adult multi-choice trials were restricted to species that could sustain larval development to give some indication of the acceptability of these species for adult feeding and oviposition. Although adult feeding was initially concentrated on B. alba, the oviposition preference was clear-cut as females only oviposited on A. cordifolia. In order to quantify the impact of Phenrica sp. 2 on plant biomass and to assess the incidence and intensity of foliar damage, a pair of adults was confined to the host plant, for 2 generations, with different levels of larval densities. The results indicated that the host plant, due to both larval and adult feeding, suffered leaf losses of up to 55%. Anredera cordifolia was however still capable of enlarging the root mass despite suffering huge leaf losses. This would imply that A. cordifolia has an effective re-growth capacity and it will only be vulnerable to attack of the storage organs that enable re-growth, or to repeated attack of other plant parts through which reserves are exhausted. Unfortunately the period of exposure (24 days) was too short to prove that Phenrica sp. 2 impacts on the below ground dry mass, but should the plant be completely defoliated, as was observed in the field, the host plant would be forced to deplete stored resources. Phenrica sp.2 has shown to be very host specific and although A.cordifoia loses its leaves during the winter period in most provinces in South Africa, the adults are long-lived and should be able to survive the leafless periods. Further more the relatively short life cycle, high fecundity and 3 generations per year should theoretically insure a strong population build-up that would improve the chances of establishment in the field. All indications are that Phenrica sp. 2 is an agent well worth considering for the biological control of A. cordifolia.
- Full Text:
- Date Issued: 2006
- Authors: Van der Westhuizen, Liamé
- Date: 2006
- Subjects: Weeds -- Biological control -- South Africa , Biological pest control agents -- South Africa , Invasive plants -- Biological control -- South Africa , Chrysomelidae , Beetles , Flea beetles , Anredera cordifolia -- Biological control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5689 , http://hdl.handle.net/10962/d1005375 , Weeds -- Biological control -- South Africa , Biological pest control agents -- South Africa , Invasive plants -- Biological control -- South Africa , Chrysomelidae , Beetles , Flea beetles , Anredera cordifolia -- Biological control
- Description: Anredera cordifolia (Basellaceae), Madeira vine, is a perennial, semi- succulent climber native from Paraguay to southern Brazil and northern Argentina. It has a history of weediness and difficulty of control once established. In South Africa Madeira vine has a wide range and distribution with altitudes ranging from 10-1800m above sea level. Described as a transformer species, its sheer weight is capable of breaking branches off trees, causing the potential collapse of forest canopies. Chemical and mechanical control methods are expensive, labour intensive and may provide only temporary relief. A biological control programme was therefore initiated in 2003. Cf Phenrica sp. 2 (Coleoptera: Chrysomelidae: Alticinae), was field collected from A. cordifolia in Brazil, SSW of Cascavel in the Paraná Province during a survey in November 2003. Eggs are laid in groups of 16 with the average fertility rate being 89%. After going though three larval instars, the larvae pupate in the soil with the adults eclosing after a period of 17 days. The total developmental time for a generation from egg to egg ranges between 7-8 weeks. Biological traits that favour the flea beetle as a possible biological control agent include long-lived adults (up to 5 months) and multiple generations during the summer period. Both adults and larvae feed extensively on leaves and stems and although developmental rates will slow down during the winter period, no indication of a definite diapause was found under the prevailing laboratory conditions. After completing the larval no-choice trials with twenty-six plant species from 14 plant families Phenrica sp. 2 proved to be adequately host specific, as larval development was only supported by 3 Basellaceae species (including the control A. cordifolia) and one Portulacaceae species. All of these are introduced species in South Africa. The only indigenous Basella species could not be tested as it has a very marginal distribution, and because it’s inconspicuous nature, it is seldom seen or collected. Adult multi-choice trials were restricted to species that could sustain larval development to give some indication of the acceptability of these species for adult feeding and oviposition. Although adult feeding was initially concentrated on B. alba, the oviposition preference was clear-cut as females only oviposited on A. cordifolia. In order to quantify the impact of Phenrica sp. 2 on plant biomass and to assess the incidence and intensity of foliar damage, a pair of adults was confined to the host plant, for 2 generations, with different levels of larval densities. The results indicated that the host plant, due to both larval and adult feeding, suffered leaf losses of up to 55%. Anredera cordifolia was however still capable of enlarging the root mass despite suffering huge leaf losses. This would imply that A. cordifolia has an effective re-growth capacity and it will only be vulnerable to attack of the storage organs that enable re-growth, or to repeated attack of other plant parts through which reserves are exhausted. Unfortunately the period of exposure (24 days) was too short to prove that Phenrica sp. 2 impacts on the below ground dry mass, but should the plant be completely defoliated, as was observed in the field, the host plant would be forced to deplete stored resources. Phenrica sp.2 has shown to be very host specific and although A.cordifoia loses its leaves during the winter period in most provinces in South Africa, the adults are long-lived and should be able to survive the leafless periods. Further more the relatively short life cycle, high fecundity and 3 generations per year should theoretically insure a strong population build-up that would improve the chances of establishment in the field. All indications are that Phenrica sp. 2 is an agent well worth considering for the biological control of A. cordifolia.
- Full Text:
- Date Issued: 2006
Stochastic models in finance
- Authors: Mazengera, Hassan
- Date: 2017
- Subjects: Finance -- Mathematical models , C++ (Computer program language) , GARCH model , Lebesgue-Radon-Nikodym theorems , Radon measures , Stochastic models , Stochastic processes , Stochastic processes -- Computer programs , Martingales (Mathematics) , Pricing -- Mathematical models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/162724 , vital:40976
- Description: Stochastic models for pricing financial securities are developed. First, we consider the Black Scholes model, which is a classic example of a complete market model and finally focus on Lévy driven models. Jumps may render the market incomplete and are induced in a model by inclusion of a Poisson process. Lévy driven models are more realistic in modelling of asset price dynamics than the Black Scholes model. Martingales are central in pricing, especially of derivatives and we give them the desired attention in the context of pricing. There are an increasing number of important pricing models where analytical solutions are not available hence computational methods come in handy, see Broadie and Glasserman (1997). It is also important to note that computational methods are also applicable to models with analytical solutions. We computationally value selected stochastic financial models using C++. Computational methods are also used to value or price complex financial instruments such as path dependent derivatives. This pricing procedure is applied in the computational valuation of a stochastic (revenue based) loan contract. Derivatives with simple pay of functions and models with analytical solutions are considered for illustrative purposes. The Black-Scholes P.D.E is complex to solve analytically and finite difference methods are widely used. Explicit finite difference scheme is considered in this thesis for computational valuation of derivatives that are modelled by the Black-Scholes P.D.E. Stochastic modelling of asset prices is important for the valuation of derivatives: Gaussian, exponential and gamma variates are simulated for the valuation purposes.
- Full Text:
- Date Issued: 2017
- Authors: Mazengera, Hassan
- Date: 2017
- Subjects: Finance -- Mathematical models , C++ (Computer program language) , GARCH model , Lebesgue-Radon-Nikodym theorems , Radon measures , Stochastic models , Stochastic processes , Stochastic processes -- Computer programs , Martingales (Mathematics) , Pricing -- Mathematical models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/162724 , vital:40976
- Description: Stochastic models for pricing financial securities are developed. First, we consider the Black Scholes model, which is a classic example of a complete market model and finally focus on Lévy driven models. Jumps may render the market incomplete and are induced in a model by inclusion of a Poisson process. Lévy driven models are more realistic in modelling of asset price dynamics than the Black Scholes model. Martingales are central in pricing, especially of derivatives and we give them the desired attention in the context of pricing. There are an increasing number of important pricing models where analytical solutions are not available hence computational methods come in handy, see Broadie and Glasserman (1997). It is also important to note that computational methods are also applicable to models with analytical solutions. We computationally value selected stochastic financial models using C++. Computational methods are also used to value or price complex financial instruments such as path dependent derivatives. This pricing procedure is applied in the computational valuation of a stochastic (revenue based) loan contract. Derivatives with simple pay of functions and models with analytical solutions are considered for illustrative purposes. The Black-Scholes P.D.E is complex to solve analytically and finite difference methods are widely used. Explicit finite difference scheme is considered in this thesis for computational valuation of derivatives that are modelled by the Black-Scholes P.D.E. Stochastic modelling of asset prices is important for the valuation of derivatives: Gaussian, exponential and gamma variates are simulated for the valuation purposes.
- Full Text:
- Date Issued: 2017
An investigation of how Visual Technology for the Autonomous Learning of Mathematics (VITALmaths) video clips on mobile phones can be used by student teachers as a visualisation tool in the teaching of Number Sense: a case study
- Authors: Kangwa, Lemmy
- Date: 2017
- Subjects: Mathematics -- Study and teaching -- Zambia -- Case studies , Visualization , Number concept , Mobile communication systems in education , Mathematics -- Study and teaching -- Software , Telecommunications in education , Educational innovations , VITALmaths
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/6930 , vital:21201
- Description: Visualisation is increasingly being recognised as having a significant role in the learning of mathematics especially when students are solving mathematical problems (Thornton, 2001). It is argued that visualisation is a powerful tool for learners to construct mental and physical representations that correctly mirror mathematical relationships and concepts. To gain a thorough understanding of the scope of visualisation, three Visual Technology for Autonomous Learning of Mathematics (VITALmaths) (www.vitalmaths.com) video clips were uploaded on mobile phones of each of the eleven participating student teachers who used them in their teaching practice. This is in cognisance of the educational potential offered by mobile phones and their current pervasiveness in the daily lives of both teachers and learners in Zambia (Zambia. Ministry of Education [M.O.E], 2013]). This study sought to investigate how VITALmaths video clips on mobile phones could be used by student teachers as a visualisation tool in the teaching of Number Sense. The videos of the lessons formed the core of my analysis. The study was conducted at four primary schools by eleven student teachers of a public university in Zambia. The study is framed as a case study and is grounded within the interpretive paradigm. The findings revealed that the student teachers’ use of the video clips in the classrooms for teaching was generally approached from two perspectives: at the beginning of the lesson or at the end. The videos were used at the beginning of the lesson as a means to introduce a topic or an idea, and at the end of the lesson to consolidate what was taught. The videos were also used to enhance the conceptual understanding of Number Sense. The findings also revealed that students encountered both enabling and constraining factors in their use of mobile phones to teach number sense. The overall findings revealed that, if well utilised, mobile phones as visualisation tools had the potential to enhance the teaching of Mathematics in general and Number Sense in particular, and therefore teachers should be encouraged to use them in their teaching.
- Full Text:
- Date Issued: 2017
- Authors: Kangwa, Lemmy
- Date: 2017
- Subjects: Mathematics -- Study and teaching -- Zambia -- Case studies , Visualization , Number concept , Mobile communication systems in education , Mathematics -- Study and teaching -- Software , Telecommunications in education , Educational innovations , VITALmaths
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/6930 , vital:21201
- Description: Visualisation is increasingly being recognised as having a significant role in the learning of mathematics especially when students are solving mathematical problems (Thornton, 2001). It is argued that visualisation is a powerful tool for learners to construct mental and physical representations that correctly mirror mathematical relationships and concepts. To gain a thorough understanding of the scope of visualisation, three Visual Technology for Autonomous Learning of Mathematics (VITALmaths) (www.vitalmaths.com) video clips were uploaded on mobile phones of each of the eleven participating student teachers who used them in their teaching practice. This is in cognisance of the educational potential offered by mobile phones and their current pervasiveness in the daily lives of both teachers and learners in Zambia (Zambia. Ministry of Education [M.O.E], 2013]). This study sought to investigate how VITALmaths video clips on mobile phones could be used by student teachers as a visualisation tool in the teaching of Number Sense. The videos of the lessons formed the core of my analysis. The study was conducted at four primary schools by eleven student teachers of a public university in Zambia. The study is framed as a case study and is grounded within the interpretive paradigm. The findings revealed that the student teachers’ use of the video clips in the classrooms for teaching was generally approached from two perspectives: at the beginning of the lesson or at the end. The videos were used at the beginning of the lesson as a means to introduce a topic or an idea, and at the end of the lesson to consolidate what was taught. The videos were also used to enhance the conceptual understanding of Number Sense. The findings also revealed that students encountered both enabling and constraining factors in their use of mobile phones to teach number sense. The overall findings revealed that, if well utilised, mobile phones as visualisation tools had the potential to enhance the teaching of Mathematics in general and Number Sense in particular, and therefore teachers should be encouraged to use them in their teaching.
- Full Text:
- Date Issued: 2017
An automatic programming system to generate payroll programs
- Fielding, Elizabeth Vera Catherine
- Authors: Fielding, Elizabeth Vera Catherine
- Date: 1979
- Subjects: Computer software -- Development , Programming (computers) , Software architecture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4695 , http://hdl.handle.net/10962/d1011829 , Computer software -- Development , Programming (computers) , Software architecture
- Description: The purpose of this project was to try to investigate one approach to the problem of automatically generating programs from some specification. Rather than following the approach which requires the user to define his problem using some formulation, it was decided to look at a class of problems that have similar solutions, but have many variations, and to try to design a system capable of obtaining user requirements and generating solutions tailored to these requirements. The aim was to design the system in such a way that it could be extended to cater for other classes of problems, so that eventually a system which could automatically generate program solutions for a range of problems might be developed. Intro. p. 1.
- Full Text:
- Date Issued: 1979
- Authors: Fielding, Elizabeth Vera Catherine
- Date: 1979
- Subjects: Computer software -- Development , Programming (computers) , Software architecture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4695 , http://hdl.handle.net/10962/d1011829 , Computer software -- Development , Programming (computers) , Software architecture
- Description: The purpose of this project was to try to investigate one approach to the problem of automatically generating programs from some specification. Rather than following the approach which requires the user to define his problem using some formulation, it was decided to look at a class of problems that have similar solutions, but have many variations, and to try to design a system capable of obtaining user requirements and generating solutions tailored to these requirements. The aim was to design the system in such a way that it could be extended to cater for other classes of problems, so that eventually a system which could automatically generate program solutions for a range of problems might be developed. Intro. p. 1.
- Full Text:
- Date Issued: 1979
An investigation into the school experiences of HIV-positive secondary school learners on ARV treatment in Katutura, Windhoek
- Authors: Haipinge, Emilie
- Date: 2013
- Subjects: HIV-positive youth -- Namibia -- Katutura (Windhoek) HIV-positive youth -- Social conditions -- Namibia -- Katutura (Windhoek) HIV infections -- Social aspects -- Namibia -- Katutura (Windhoek) HIV infections -- Psychological aspects -- Namibia -- Katutura (Windhoek) AIDS phobia -- Namibia -- Katutura (Windhoek) Antiretroviral agents
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1837 , http://hdl.handle.net/10962/d1004334
- Description: What are the school experiences of HIV-positive secondary school learners on ARV treatment? Although the provision of life-saving antiretroviral (ARV) treatment is central in the medical and policy response to the HIV pandemic, relatively little research (in the SADC region and in Namibia particularly) attends to people’s experiences and the social effects of taking ARV treatment. This study probed the experiences of high school learners on ARV treatment in Khomas Region, Namibia. As researcher I used a qualitative case study design based mainly on interviews with a purposive, select sample of eight learners at the school where I am a teacher-counsellor. Methods used also included: observations; focus group interviews with eight teachers at the site school; a questionnaire survey with Life Skills teachers from 25 schools in the Khomas Region; and document analysis. Using a theory of health-related stigma and discrimination as well as perspectives on resilience and agency as conceptual and analytical lenses, this study found that only a handful of these learners were living openly with HIV and AIDS. Being both HIV-positive and on ARV medication was a double bind for learners facing pervasive stigma and discrimination in and out of school. Discourses associated with HIV and AIDS, sex, and sexuality shaped people’s response to them and they feared being ‘caught out’. Here the study explores the complex reciprocal relationship between cause and effect in stigma, showing some consequences for these learners: isolation (both voluntary and imposed), mental anguish, depression and suicidal leanings; also (at school) absenteeism, grade repetition and dropout. Distinguishing stigma from discrimination in this study enabled insight into actual practices that constrain learner participation and inclusion in and out of school. Trust between learners on ARVs and teachers proved to be low. Teacher respondents not only felt unequipped to deal with the psychosocial needs of learners on ARVs but also indicated that confronting these needs animated their personal vulnerability (around HIV-related experiences in their own families). However, hopeful patterns also emerged. Some mediatory factors out of school shaped these learners’ experiences and identities positively, with implications for in-school experiences and participation. Some learner journeys reflected shifts from deep despair towards the emergence of voice, positive self-concepts and resilient dispositions. Here, also, this study enters a neglected area of research, showing how the complex interplay of learners’ own agency with social support brought these positive outcomes. Most learners had experienced rejection from immediate family, receiving support rather from community members who became ‘family’. The study thus also raises pressing questions on the nature of support structures (both in and out of school) in contexts shaped by HIV and AIDS, where stigma and discrimination are pervasive and where stable family structures, parental oversight and ‘normal’ progression through school cannot be assumed. It recommends that schools gain better insight into how learners’ circumstances shape their experiences, and develop internal policies, procedures and networks to reduce stigma and discrimination against HIV-positive learners on ARV treatment, as well as. ensuring material, medical, emotional, and psychological support for them.
- Full Text:
- Date Issued: 2013
- Authors: Haipinge, Emilie
- Date: 2013
- Subjects: HIV-positive youth -- Namibia -- Katutura (Windhoek) HIV-positive youth -- Social conditions -- Namibia -- Katutura (Windhoek) HIV infections -- Social aspects -- Namibia -- Katutura (Windhoek) HIV infections -- Psychological aspects -- Namibia -- Katutura (Windhoek) AIDS phobia -- Namibia -- Katutura (Windhoek) Antiretroviral agents
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1837 , http://hdl.handle.net/10962/d1004334
- Description: What are the school experiences of HIV-positive secondary school learners on ARV treatment? Although the provision of life-saving antiretroviral (ARV) treatment is central in the medical and policy response to the HIV pandemic, relatively little research (in the SADC region and in Namibia particularly) attends to people’s experiences and the social effects of taking ARV treatment. This study probed the experiences of high school learners on ARV treatment in Khomas Region, Namibia. As researcher I used a qualitative case study design based mainly on interviews with a purposive, select sample of eight learners at the school where I am a teacher-counsellor. Methods used also included: observations; focus group interviews with eight teachers at the site school; a questionnaire survey with Life Skills teachers from 25 schools in the Khomas Region; and document analysis. Using a theory of health-related stigma and discrimination as well as perspectives on resilience and agency as conceptual and analytical lenses, this study found that only a handful of these learners were living openly with HIV and AIDS. Being both HIV-positive and on ARV medication was a double bind for learners facing pervasive stigma and discrimination in and out of school. Discourses associated with HIV and AIDS, sex, and sexuality shaped people’s response to them and they feared being ‘caught out’. Here the study explores the complex reciprocal relationship between cause and effect in stigma, showing some consequences for these learners: isolation (both voluntary and imposed), mental anguish, depression and suicidal leanings; also (at school) absenteeism, grade repetition and dropout. Distinguishing stigma from discrimination in this study enabled insight into actual practices that constrain learner participation and inclusion in and out of school. Trust between learners on ARVs and teachers proved to be low. Teacher respondents not only felt unequipped to deal with the psychosocial needs of learners on ARVs but also indicated that confronting these needs animated their personal vulnerability (around HIV-related experiences in their own families). However, hopeful patterns also emerged. Some mediatory factors out of school shaped these learners’ experiences and identities positively, with implications for in-school experiences and participation. Some learner journeys reflected shifts from deep despair towards the emergence of voice, positive self-concepts and resilient dispositions. Here, also, this study enters a neglected area of research, showing how the complex interplay of learners’ own agency with social support brought these positive outcomes. Most learners had experienced rejection from immediate family, receiving support rather from community members who became ‘family’. The study thus also raises pressing questions on the nature of support structures (both in and out of school) in contexts shaped by HIV and AIDS, where stigma and discrimination are pervasive and where stable family structures, parental oversight and ‘normal’ progression through school cannot be assumed. It recommends that schools gain better insight into how learners’ circumstances shape their experiences, and develop internal policies, procedures and networks to reduce stigma and discrimination against HIV-positive learners on ARV treatment, as well as. ensuring material, medical, emotional, and psychological support for them.
- Full Text:
- Date Issued: 2013
Foreign reference products in the registration of generic medicines in South Africa a case study
- Authors: Hwengwere, Eldinah
- Date: 2012
- Subjects: Generic drugs -- Law and legislation -- South Africa Case studies Generic drugs -- South Africa Case studies Drugs -- Law and legislation -- South Africa Case studies Pharmacy -- Law and legislation -- South Africa Case studies
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3762 , http://hdl.handle.net/10962/d1003240
- Description: Introduction: Due to the increase in healthcare costs, generic medicines have been adopted for used in both developed and developing countries. When a generic or ‘multisource interchangeable medicine’ is to be registered, studies that prove that the generic is equivalent to the Innovator Product (IP) are used. The generic medicine is required to prove that it will mirror the IP in terms of safety, quality and efficacy and, in South Africa, the Medicines Control Council (MCC) ensures that generic medicines meet these requirements. Generic medicines may be registered using bioequivalence data obtained from comparison with a domestic reference product (usually the local innovator product) or in certain cases, a foreign reference product (FRP). The bioequivalence data can either be from in vivo or in vitro studies. The MCC guidelines require that for modified release preparations, in vivo bioequivalence studies are done for approval of registration; the exception being if a proportionally higher dose has already been registered. No information is currently given to prescribers and dispensers or to the public about whether a generic product was registered against a foreign or domestic reference product. Aims and Objectives: 1.) To determine the number of generic medicines in a predetermined sample registered using a FRP as comparator and to document the transparency of pharmaceutical companies when approached to disclose information regarding the registration of these products. 2.) To describe and document the use of the Promotion of Access to Information Act (Act 2 of 2000) [PAIA] from the perspective of a ‘layperson’ in the context of medicines’ regulation, in both private and public bodies. Methods: 20 modified release and Biopharmaceutics Classification System (BCS) class IV products were selected from the ‘generics dictionary’ – a commercial publication – and letters were sent to the manufacturers of the products requesting information about the tests done to prove equivalence and whether they were performed against a domestic or foreign reference product. The same information was also requested from the MCC. The requests were all made using the Promotion of Access to Information Act (PAIA). Results: Nine companies were represented by the 20 products chosen. Information was obtained about thirteen products. Ten of these products were registered using FRPs. Four products were registered based only on comparative dissolution studies. Four companies provided the requested information, two companies responded by refusing the requests and three did not respond at all. The MCC refused the request for information even after an internal appeal was lodged. Conclusions: The Promotion of Access to information Act was unsuccessful in obtaining information from the public body, and partly successful in obtaining it from the private bodies. While the title of the Act seems to indicate that the Act can be used to obtain information as such, it only provides for access to specified records. The MCC and the pharmaceutical companies involved in the study were under no obligation to provide the information as the request had not complied with PAIA requirements. The use of FRPs for registration is a reality in the pharmaceutical industry in South Africa. Neither the public nor healthcare professionals who prescribe medicines or who are involved in dispensing generic medicines as substitutes are aware of whether or not a FRP has been used to register a generic. Interchangeability cannot necessarily be guaranteed if the reference product was not proven equivalent to the local innovator product. It is debatable as to whether or not this information would be of any particular benefit to members of the public. Prescribers may choose to write ‘no substitution’ on their prescriptions if they were unconvinced that an FRP is acceptable. This could have consequences for healthcare costs. Dispensers are the most vulnerable in South Africa as they are obliged by law to substitute generic medicines when innovator medicines have been prescribed. Dispensers’ views on the acceptability of the use of FRPs can be seen as irrelevant. In the end, as this study demonstrates, the only option in the present situation is to rely entirely on the MCC’s rigour in assessing applications for registration of generic medicines.
- Full Text:
- Date Issued: 2012
- Authors: Hwengwere, Eldinah
- Date: 2012
- Subjects: Generic drugs -- Law and legislation -- South Africa Case studies Generic drugs -- South Africa Case studies Drugs -- Law and legislation -- South Africa Case studies Pharmacy -- Law and legislation -- South Africa Case studies
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3762 , http://hdl.handle.net/10962/d1003240
- Description: Introduction: Due to the increase in healthcare costs, generic medicines have been adopted for used in both developed and developing countries. When a generic or ‘multisource interchangeable medicine’ is to be registered, studies that prove that the generic is equivalent to the Innovator Product (IP) are used. The generic medicine is required to prove that it will mirror the IP in terms of safety, quality and efficacy and, in South Africa, the Medicines Control Council (MCC) ensures that generic medicines meet these requirements. Generic medicines may be registered using bioequivalence data obtained from comparison with a domestic reference product (usually the local innovator product) or in certain cases, a foreign reference product (FRP). The bioequivalence data can either be from in vivo or in vitro studies. The MCC guidelines require that for modified release preparations, in vivo bioequivalence studies are done for approval of registration; the exception being if a proportionally higher dose has already been registered. No information is currently given to prescribers and dispensers or to the public about whether a generic product was registered against a foreign or domestic reference product. Aims and Objectives: 1.) To determine the number of generic medicines in a predetermined sample registered using a FRP as comparator and to document the transparency of pharmaceutical companies when approached to disclose information regarding the registration of these products. 2.) To describe and document the use of the Promotion of Access to Information Act (Act 2 of 2000) [PAIA] from the perspective of a ‘layperson’ in the context of medicines’ regulation, in both private and public bodies. Methods: 20 modified release and Biopharmaceutics Classification System (BCS) class IV products were selected from the ‘generics dictionary’ – a commercial publication – and letters were sent to the manufacturers of the products requesting information about the tests done to prove equivalence and whether they were performed against a domestic or foreign reference product. The same information was also requested from the MCC. The requests were all made using the Promotion of Access to Information Act (PAIA). Results: Nine companies were represented by the 20 products chosen. Information was obtained about thirteen products. Ten of these products were registered using FRPs. Four products were registered based only on comparative dissolution studies. Four companies provided the requested information, two companies responded by refusing the requests and three did not respond at all. The MCC refused the request for information even after an internal appeal was lodged. Conclusions: The Promotion of Access to information Act was unsuccessful in obtaining information from the public body, and partly successful in obtaining it from the private bodies. While the title of the Act seems to indicate that the Act can be used to obtain information as such, it only provides for access to specified records. The MCC and the pharmaceutical companies involved in the study were under no obligation to provide the information as the request had not complied with PAIA requirements. The use of FRPs for registration is a reality in the pharmaceutical industry in South Africa. Neither the public nor healthcare professionals who prescribe medicines or who are involved in dispensing generic medicines as substitutes are aware of whether or not a FRP has been used to register a generic. Interchangeability cannot necessarily be guaranteed if the reference product was not proven equivalent to the local innovator product. It is debatable as to whether or not this information would be of any particular benefit to members of the public. Prescribers may choose to write ‘no substitution’ on their prescriptions if they were unconvinced that an FRP is acceptable. This could have consequences for healthcare costs. Dispensers are the most vulnerable in South Africa as they are obliged by law to substitute generic medicines when innovator medicines have been prescribed. Dispensers’ views on the acceptability of the use of FRPs can be seen as irrelevant. In the end, as this study demonstrates, the only option in the present situation is to rely entirely on the MCC’s rigour in assessing applications for registration of generic medicines.
- Full Text:
- Date Issued: 2012
What can TOLs reveal about the nature of ESL reading? : a critical evaluation of current ESL research utilising think-aloud protocols
- Authors: Dixon, Robyn
- Date: 1993
- Subjects: English language -- Study and teaching -- Foreign speakers Reading comprehension Reading -- Research
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1823 , http://hdl.handle.net/10962/d1003709
- Description: This thesis explores the efficacy of think-aloud protocols (TOLs), and the extent to which the TOL technique is able to reveal the nature of ESL reading interaction with expository prose. The investigation constituted a critical evaluation of current ESL TOL research, which was essentially a theoretical examination of emerging problems derived from an in-depth assessment of current ESL TOL studies. The theoretical examination was supplemented by the practical implementation of the technique in a case study research, utilising three verbal protocols obtained from ESL students at the University of Fort Hare. The close observation afforded by the evaluative case study research paradigm provided the writer - as participant observer - with a further means of judging the merit of TOLs, which corroborated findings from the theoretical evaluation, and enabled a consideration of unanticipated issues which emerged from the practical implementation of the technique. The conclusion was that TOLs seem to have a unique ability to identify aspects of the nature of ESL reading gained from an on-line assessment of reader interaction, provided that TOL research is conducted within certain methodological and analytic research constraints. The writer has proffered suggestions for future ESL TOL research, and feels that the combination of TOL research findings with other measures of reading comprehension could elucidate aspects of ESL comprehension, making a valuable contribution to ESL reading theory and practice.
- Full Text:
- Date Issued: 1993
- Authors: Dixon, Robyn
- Date: 1993
- Subjects: English language -- Study and teaching -- Foreign speakers Reading comprehension Reading -- Research
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1823 , http://hdl.handle.net/10962/d1003709
- Description: This thesis explores the efficacy of think-aloud protocols (TOLs), and the extent to which the TOL technique is able to reveal the nature of ESL reading interaction with expository prose. The investigation constituted a critical evaluation of current ESL TOL research, which was essentially a theoretical examination of emerging problems derived from an in-depth assessment of current ESL TOL studies. The theoretical examination was supplemented by the practical implementation of the technique in a case study research, utilising three verbal protocols obtained from ESL students at the University of Fort Hare. The close observation afforded by the evaluative case study research paradigm provided the writer - as participant observer - with a further means of judging the merit of TOLs, which corroborated findings from the theoretical evaluation, and enabled a consideration of unanticipated issues which emerged from the practical implementation of the technique. The conclusion was that TOLs seem to have a unique ability to identify aspects of the nature of ESL reading gained from an on-line assessment of reader interaction, provided that TOL research is conducted within certain methodological and analytic research constraints. The writer has proffered suggestions for future ESL TOL research, and feels that the combination of TOL research findings with other measures of reading comprehension could elucidate aspects of ESL comprehension, making a valuable contribution to ESL reading theory and practice.
- Full Text:
- Date Issued: 1993
Breaking the silence : Zanele's journey to recovery
- Authors: Payne, Charmaine
- Date: 2007
- Subjects: Rape victims -- Counseling of -- South Africa Rape victims -- Counseling of -- South Africa -- Case studies Post-traumatic stress disorder -- Patients -- Rehabilitation Post-traumatic stress disorder -- Patients -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3161 , http://hdl.handle.net/10962/d1007651
- Description: This study employed a case-based research design to document the psychological assessment and treatment of Zanele, a 15-year-old black Xhosa speaking female who was raped twice in 2006 by the same perpetrator. The aim of the study was to explore whether, the model for assessment and intervention for posttraumatic stress disorder (PTSD) developed by Ehlers and Clark (2000) was effective and transportable to the South African context. Zanele had a sufficient understanding of English for assessment to proceed without use of an interpreter. She reported a number of PTSD symptoms which were causing her significant distress and had impacted on her social and educational functioning. These included flashbacks of the perpetrator's face when she looked at the faces of black men, nightmares about the traumas she had endured and feeling isolated from others. A number of cognitive techniques were utilised in this study, however the central interventions included working with triggers, imagery rehearsal techniques with a focus on nightmares, and reliving with cognitive restructuring within and outside reliving. Psychoeducation and increasing her social support were also important components of the intervention. Her progress was monitored by means of several self-report measures which were displayed in graphic and tabular form. In addition, a thematically selective narrative of the assessment and first 23 sessions of the intervention was written which documents some of the central processes set in motion by the interventions. These results provide evidence that this model was both effective and transportable to the South African population. In addition, the study demonstrated that it is possible for a white English speaking clinician to work with a black Xhosa speaking individual and make substantial therapeutic gains.
- Full Text:
- Date Issued: 2007
- Authors: Payne, Charmaine
- Date: 2007
- Subjects: Rape victims -- Counseling of -- South Africa Rape victims -- Counseling of -- South Africa -- Case studies Post-traumatic stress disorder -- Patients -- Rehabilitation Post-traumatic stress disorder -- Patients -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3161 , http://hdl.handle.net/10962/d1007651
- Description: This study employed a case-based research design to document the psychological assessment and treatment of Zanele, a 15-year-old black Xhosa speaking female who was raped twice in 2006 by the same perpetrator. The aim of the study was to explore whether, the model for assessment and intervention for posttraumatic stress disorder (PTSD) developed by Ehlers and Clark (2000) was effective and transportable to the South African context. Zanele had a sufficient understanding of English for assessment to proceed without use of an interpreter. She reported a number of PTSD symptoms which were causing her significant distress and had impacted on her social and educational functioning. These included flashbacks of the perpetrator's face when she looked at the faces of black men, nightmares about the traumas she had endured and feeling isolated from others. A number of cognitive techniques were utilised in this study, however the central interventions included working with triggers, imagery rehearsal techniques with a focus on nightmares, and reliving with cognitive restructuring within and outside reliving. Psychoeducation and increasing her social support were also important components of the intervention. Her progress was monitored by means of several self-report measures which were displayed in graphic and tabular form. In addition, a thematically selective narrative of the assessment and first 23 sessions of the intervention was written which documents some of the central processes set in motion by the interventions. These results provide evidence that this model was both effective and transportable to the South African population. In addition, the study demonstrated that it is possible for a white English speaking clinician to work with a black Xhosa speaking individual and make substantial therapeutic gains.
- Full Text:
- Date Issued: 2007