Searching for new relevance in the 1990s: the Organization of African Unity as an instrument of conflict resolution
- Authors: Dlamini, Thandeka Lungile
- Date: 2000
- Subjects: Organization of African Unity , Africa -- Foreign relations , Conflict management -- Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2770 , http://hdl.handle.net/10962/d1002980 , Organization of African Unity , Africa -- Foreign relations , Conflict management -- Africa
- Description: The 1960's and the 1970's marked a great Pan-African movement in Africa, that saw the liberation of most African states. This Pan-African movement, was spearheaded by a quest to unite Africa, and to abate foreign occupation. Amidst the spirit of unity, lay a promise of an organization that would embody the hopes and aspirations of a continent undergoing a re-birth; a progression towards self-determination, economic development and integration, and the maintenance of peace. Therefore, the inception ofthe Organization of African Unity (OAD) was not only a symbol of a unifying force for Africans, but a diplomatic platform that would promote African needs on the international arena. In effect the OAU, at its inception, was for specific ideals that would guarantee liberation and unity of African states. The outcome of these ideals would be greater regional economic integration and the achievement of peace and stability. These ideals mirrored the structural definition of regional organization, with the inclusion of a Commission for Mediation Arbitration and Conciliation under the OAU Charter, to handle disputes among member states. However, the mere fact that this commission lacked the political wherewithal to resolve conflicts, by its sheer lack of a standing peacekeeping force, contributed to the inefficiency of the organization to play an effective role in conflict management. This study attempts to examine the role ofthe OAU in settling disputes. The study sought to accomplish this, in the following manner. Firstly, an investigation into the nature of conflict and why it persists in Africa was conducted. Further, an examination ofthe tools that practitioners utilize not only to study conflict, but to prevent, manage and resolve it, was done. During the investigation it was found that, although the OAU's greatest successes have come from preventive diplomacy, its structural foundations limit the capabilities of the organization to become more relevant. The Charter of the OAU alludes vaguely to the settlement of disputes, but without an executive political decision-making body able to deploy peacekeepers, its principles are largely meaningless. Amidst the growing concerns, the OAU as a matter of survival, developed initiatives it hopes will make it more effective and relevant. The focus ofthe study was the evolving role ofthe OAU, from its inception to its new role as an instrument of conflict resolution. Most of the scholarly work conducted on the OAU, is concerned with depicting a terminal organization, with little or no hope of surviving. Little emphasis is placed on prescribing remedies on how to improve and restructure the organization. The findings included, inter alia, that the organization is faced with enormous challenges, as the sources of conflict are varied and complex. Africa is now the landscape of collapsed states, economic stagnation, environmental degradation, disease and chronic conflicts. The OAU shoulders much ofthe responsibility for not sanctioning governments that contribute to the decay and suffering of the African peoples. Most ofthe criticism of the OAU, stem from the inability of the organization to play an effective role in resolving conflicts in Africa. Most of Africa's conflicts stem from a lack of political legitimacy, lack of democratic institutions, uneven distribution of resources, ethnic tensions and economic stagnation. Until such problems are addressed, Africa will continue to host the world's deadliest conflicts.
- Full Text:
- Date Issued: 2000
- Authors: Dlamini, Thandeka Lungile
- Date: 2000
- Subjects: Organization of African Unity , Africa -- Foreign relations , Conflict management -- Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2770 , http://hdl.handle.net/10962/d1002980 , Organization of African Unity , Africa -- Foreign relations , Conflict management -- Africa
- Description: The 1960's and the 1970's marked a great Pan-African movement in Africa, that saw the liberation of most African states. This Pan-African movement, was spearheaded by a quest to unite Africa, and to abate foreign occupation. Amidst the spirit of unity, lay a promise of an organization that would embody the hopes and aspirations of a continent undergoing a re-birth; a progression towards self-determination, economic development and integration, and the maintenance of peace. Therefore, the inception ofthe Organization of African Unity (OAD) was not only a symbol of a unifying force for Africans, but a diplomatic platform that would promote African needs on the international arena. In effect the OAU, at its inception, was for specific ideals that would guarantee liberation and unity of African states. The outcome of these ideals would be greater regional economic integration and the achievement of peace and stability. These ideals mirrored the structural definition of regional organization, with the inclusion of a Commission for Mediation Arbitration and Conciliation under the OAU Charter, to handle disputes among member states. However, the mere fact that this commission lacked the political wherewithal to resolve conflicts, by its sheer lack of a standing peacekeeping force, contributed to the inefficiency of the organization to play an effective role in conflict management. This study attempts to examine the role ofthe OAU in settling disputes. The study sought to accomplish this, in the following manner. Firstly, an investigation into the nature of conflict and why it persists in Africa was conducted. Further, an examination ofthe tools that practitioners utilize not only to study conflict, but to prevent, manage and resolve it, was done. During the investigation it was found that, although the OAU's greatest successes have come from preventive diplomacy, its structural foundations limit the capabilities of the organization to become more relevant. The Charter of the OAU alludes vaguely to the settlement of disputes, but without an executive political decision-making body able to deploy peacekeepers, its principles are largely meaningless. Amidst the growing concerns, the OAU as a matter of survival, developed initiatives it hopes will make it more effective and relevant. The focus ofthe study was the evolving role ofthe OAU, from its inception to its new role as an instrument of conflict resolution. Most of the scholarly work conducted on the OAU, is concerned with depicting a terminal organization, with little or no hope of surviving. Little emphasis is placed on prescribing remedies on how to improve and restructure the organization. The findings included, inter alia, that the organization is faced with enormous challenges, as the sources of conflict are varied and complex. Africa is now the landscape of collapsed states, economic stagnation, environmental degradation, disease and chronic conflicts. The OAU shoulders much ofthe responsibility for not sanctioning governments that contribute to the decay and suffering of the African peoples. Most ofthe criticism of the OAU, stem from the inability of the organization to play an effective role in resolving conflicts in Africa. Most of Africa's conflicts stem from a lack of political legitimacy, lack of democratic institutions, uneven distribution of resources, ethnic tensions and economic stagnation. Until such problems are addressed, Africa will continue to host the world's deadliest conflicts.
- Full Text:
- Date Issued: 2000
The emergence and expression of teachers’ identities in teaching foundation phase mathematics
- Authors: Westaway, Lise
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7000 , vital:21208
- Description: The assertion that learner performance in South African schools is in crisis may be cliched but it is certainly true. The majority of learners in the schooling system are not achieving the required outcomes, particularly in language and mathematics. I use the underperformance of learners in mathematics as the impetus for my research which seeks to understand how teachers’ identities emerge and are expressed in teaching Foundation Phase mathematics. The research contributes to an emerging scholarship that strives to explain underperformance and quality in mathematics classrooms beyond structuralist theorising. Recently research, particularly in South Africa, has begun to look more closely at who the teacher is and how the teacher is key in understanding what happens in the mathematics classroom. This emerging scholarship focuses on teacher identities. Research that foregrounds teacher identities within the field of mathematics education tends to be situated within a social constructionist orientation, which assumes that our knowledge of self and the world comes from our interactions with people and not some ‘objective’ reality (Berger & Luckman, 1966). Such a perspective appears to conflate questions of how we know something with what is. In other words, it elides structure and agency, thereby making research that seeks to examine the interplay between the two in the formation and expression of teachers’ identities, practically impossible. It is for this reason, as well as the need to move beyond the hermeneutic, that my research draws on Margaret Archer’s (1995, 1996, 2000) social realist framework. Social realism posits a relativist epistemology but a realist ontology. It is underpinned by the notion of a stratified reality with structural mechanisms giving rise to events in the world whether we experience them or not. It is only through the (inter)actions of persons that such mechanisms have the tendential power to constrain or enable the projects of persons. As such, my research seeks to identify the structural and agential mechanisms that give rise to teachers’ identities and how these identities are expressed in teaching Foundation Phase mathematics. In my research, teacher identity refers to the manner in which teachers express their social roles as teachers. In the research I use a case study methodology. I provide rich data on four isiXhosa teachers teaching in low socio-economic status schools. This data is gleaned through interviews and classroom based observations which were recorded as field notes and video transcripts. Analysis of the data occurs through the thought processes of abduction and retroduction (Danermark, Ekstrom, Jakobsen, & Karlsson, 2002). These thought process enable me to (re)describe and (re)contextualise the object of study. Through the process of asking transfactual questions I identify the structural, cultural and agential mechanisms giving rise to teachers’ identities and their expression in teaching foundation phase mathematics. There are three significant findings in my research. Firstly, research that attempts to understand the emergence and expression of teacher identities should consider their broad contextual realities. The historical, economic, social and political contexts in which the teachers are born and live, influences their sense of self, personal identities and social identities (teacher identities) and as such, influences their decision to become teachers and how they express their roles as teachers of Foundation Phase mathematics. Secondly, my research suggests that teachers’ mode of reflexivity is key to understanding the decisions that they make in the classroom and how they deal with the structures that condition the manner in which they express their roles as teachers. Thirdly, collective agency is necessary to bring about change in the way in which teachers express their roles in teaching Foundation Phase mathematics. My research produces new knowledge by examining the interplay of structure, culture and agency in the constitution of foundation phase teachers’ identities and their expression in teaching foundation phase mathematics. I use a social realist orientation to examine this interplay and provide an understanding of the mechanisms giving rise to the phenomenon under consideration. In this way I contribute to the extensive research on learner underperformance by focusing more explicitly on who the teacher is in the classroom.
- Full Text:
- Date Issued: 2017
- Authors: Westaway, Lise
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7000 , vital:21208
- Description: The assertion that learner performance in South African schools is in crisis may be cliched but it is certainly true. The majority of learners in the schooling system are not achieving the required outcomes, particularly in language and mathematics. I use the underperformance of learners in mathematics as the impetus for my research which seeks to understand how teachers’ identities emerge and are expressed in teaching Foundation Phase mathematics. The research contributes to an emerging scholarship that strives to explain underperformance and quality in mathematics classrooms beyond structuralist theorising. Recently research, particularly in South Africa, has begun to look more closely at who the teacher is and how the teacher is key in understanding what happens in the mathematics classroom. This emerging scholarship focuses on teacher identities. Research that foregrounds teacher identities within the field of mathematics education tends to be situated within a social constructionist orientation, which assumes that our knowledge of self and the world comes from our interactions with people and not some ‘objective’ reality (Berger & Luckman, 1966). Such a perspective appears to conflate questions of how we know something with what is. In other words, it elides structure and agency, thereby making research that seeks to examine the interplay between the two in the formation and expression of teachers’ identities, practically impossible. It is for this reason, as well as the need to move beyond the hermeneutic, that my research draws on Margaret Archer’s (1995, 1996, 2000) social realist framework. Social realism posits a relativist epistemology but a realist ontology. It is underpinned by the notion of a stratified reality with structural mechanisms giving rise to events in the world whether we experience them or not. It is only through the (inter)actions of persons that such mechanisms have the tendential power to constrain or enable the projects of persons. As such, my research seeks to identify the structural and agential mechanisms that give rise to teachers’ identities and how these identities are expressed in teaching Foundation Phase mathematics. In my research, teacher identity refers to the manner in which teachers express their social roles as teachers. In the research I use a case study methodology. I provide rich data on four isiXhosa teachers teaching in low socio-economic status schools. This data is gleaned through interviews and classroom based observations which were recorded as field notes and video transcripts. Analysis of the data occurs through the thought processes of abduction and retroduction (Danermark, Ekstrom, Jakobsen, & Karlsson, 2002). These thought process enable me to (re)describe and (re)contextualise the object of study. Through the process of asking transfactual questions I identify the structural, cultural and agential mechanisms giving rise to teachers’ identities and their expression in teaching foundation phase mathematics. There are three significant findings in my research. Firstly, research that attempts to understand the emergence and expression of teacher identities should consider their broad contextual realities. The historical, economic, social and political contexts in which the teachers are born and live, influences their sense of self, personal identities and social identities (teacher identities) and as such, influences their decision to become teachers and how they express their roles as teachers of Foundation Phase mathematics. Secondly, my research suggests that teachers’ mode of reflexivity is key to understanding the decisions that they make in the classroom and how they deal with the structures that condition the manner in which they express their roles as teachers. Thirdly, collective agency is necessary to bring about change in the way in which teachers express their roles in teaching Foundation Phase mathematics. My research produces new knowledge by examining the interplay of structure, culture and agency in the constitution of foundation phase teachers’ identities and their expression in teaching foundation phase mathematics. I use a social realist orientation to examine this interplay and provide an understanding of the mechanisms giving rise to the phenomenon under consideration. In this way I contribute to the extensive research on learner underperformance by focusing more explicitly on who the teacher is in the classroom.
- Full Text:
- Date Issued: 2017
The digital rhetoric of addressing rape culture: “official” and “unofficial” arguments at Rhodes University
- Authors: Jones, Megaera
- Date: 2020
- Subjects: Rape in universities and colleges -- South Africa -- Makhanda , Universities and colleges -- Administration -- South Africa -- Makhanda , Communication in higher education - South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142621 , vital:38096
- Description: South Africa is overwhelmed with high levels of sexual violence and institutions of higher education in South Africa are not exempt from this. How higher education stakeholders have responded to the call to address rape culture on campuses has been at the centre of much attention, especially publicly on online communicative spaces. Drawing on contemporary rhetorical theories, informed by a feminist poststructuralist perspective, this study sought to explore how constituents at Rhodes University were discussing how rape culture should (and should not be) addressed on campus. Using a rhetorical analysis, this study collected and analysed online public data from ‘official’ (institutionally sanctioned) and ‘unofficial’ (institutionally independent) communication platforms, following the 2016 rape culture student-led protest at Rhodes University. In analysing and interpreting the data from the ‘official’ sites, four major themes of discussion were evident. These rhetors argued that rape culture is a societal issue, requiring collective responsibility and effort in countering it, and that any approach to do so must abide by the bounds of the law. The University’s commitment, and continued investment to address rape culture on campus were repeatedly stated; as well as, the use of external ‘supportive’ messages that bolstered the reputation, efforts, and actions of the institution. On the ‘unofficial’ sites six broad patterns of discussion were evident. These ‘unofficial’ rhetors embodied the rape culture on campus, perceiving its effects as threatening to the physical body, which led to the adoption of the argument that rape culture needs to be ‘fought’ through physical action and support. Narrow law and order approaches were contested, and the need for a victim-centred approaches were prioritised. Additionally, doubt and suspicion were cast onto the institutional management/leadership, and the University (management/leadership body) were perceived as having ‘failed’ to address rape culture adequality. Considering this ‘failure’, a divisive rhetoric argued that the ‘fight’ against rape culture should continue, despite, and separate from, the institutional body. These findings revealed how the divisive positions these various stakeholders took created a volatile climate between University management/leadership, staff, and student. I argue that such division will continue to undermine any meaningful efforts to counter rape culture on the University campus; underscoring the difficulty, and ambiguity, that comes with attempting to address rape culture on higher education campuses. This necessitates how important it will be for scholars to research, and continue researching, the ways in which a rape culture, and the various approaches which attempt to counter it, are understood.
- Full Text:
- Date Issued: 2020
- Authors: Jones, Megaera
- Date: 2020
- Subjects: Rape in universities and colleges -- South Africa -- Makhanda , Universities and colleges -- Administration -- South Africa -- Makhanda , Communication in higher education - South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142621 , vital:38096
- Description: South Africa is overwhelmed with high levels of sexual violence and institutions of higher education in South Africa are not exempt from this. How higher education stakeholders have responded to the call to address rape culture on campuses has been at the centre of much attention, especially publicly on online communicative spaces. Drawing on contemporary rhetorical theories, informed by a feminist poststructuralist perspective, this study sought to explore how constituents at Rhodes University were discussing how rape culture should (and should not be) addressed on campus. Using a rhetorical analysis, this study collected and analysed online public data from ‘official’ (institutionally sanctioned) and ‘unofficial’ (institutionally independent) communication platforms, following the 2016 rape culture student-led protest at Rhodes University. In analysing and interpreting the data from the ‘official’ sites, four major themes of discussion were evident. These rhetors argued that rape culture is a societal issue, requiring collective responsibility and effort in countering it, and that any approach to do so must abide by the bounds of the law. The University’s commitment, and continued investment to address rape culture on campus were repeatedly stated; as well as, the use of external ‘supportive’ messages that bolstered the reputation, efforts, and actions of the institution. On the ‘unofficial’ sites six broad patterns of discussion were evident. These ‘unofficial’ rhetors embodied the rape culture on campus, perceiving its effects as threatening to the physical body, which led to the adoption of the argument that rape culture needs to be ‘fought’ through physical action and support. Narrow law and order approaches were contested, and the need for a victim-centred approaches were prioritised. Additionally, doubt and suspicion were cast onto the institutional management/leadership, and the University (management/leadership body) were perceived as having ‘failed’ to address rape culture adequality. Considering this ‘failure’, a divisive rhetoric argued that the ‘fight’ against rape culture should continue, despite, and separate from, the institutional body. These findings revealed how the divisive positions these various stakeholders took created a volatile climate between University management/leadership, staff, and student. I argue that such division will continue to undermine any meaningful efforts to counter rape culture on the University campus; underscoring the difficulty, and ambiguity, that comes with attempting to address rape culture on higher education campuses. This necessitates how important it will be for scholars to research, and continue researching, the ways in which a rape culture, and the various approaches which attempt to counter it, are understood.
- Full Text:
- Date Issued: 2020
The development of a typology of science teachers' views on the nature of science and science practical work: an evaluative pilot study
- Authors: Meiring, Leslie Frank
- Date: 1995
- Subjects: Science -- Study and teaching -- Research Science -- Study and teaching -- South Africa Science teachers -- Attitudes Science -- Philosoph
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1931 , http://hdl.handle.net/10962/d1007607
- Description: Many theories on the nature of science and the nature of learning have been proposed. In particular, two theoretical orientations have been identified as having a decisive impact on activities in the school science classroom, namely "Inductivism" and "Constructivism". Inductivism views observations as objective, facts as constants and knowledge as being obtained from a fixed external reality. The constructivist view sees all knowledge as "reality" reconstructed in the mind of the learner. Each view predisposes certain orientations towards the science curriculum and within it particularly to assessment. It is postulated that teachers' views on science will influence how they teach and assess it. An "inductivist" teacher is more likely to reward certain approved responses from learners whereas a "constructivist" teacher is more likely to attend to learners' unique observations as evidence of their thinking. In this study a questionnaire was developed in an attempt classify science teachers according to their views on the nature of science and learning, and during this process encourage them to reflect on these views. It is hoped that the instrument could measure any changes in teacher's views as a result of the teachers becoming more reflective practitioners over time. Research indicates that the majority of teachers have a predominantly inductivist view of science. The study confirmed the results of other researchers by showing that a majority of non-tertiary science educators could be classified as being strongly inductivist. However, the overall proportion of these teachers was not as high as expected. Of possible concern was the indication that the strongly constructivist group showed very strong inductivist tendencies when assessing written tests which involved pupils' responses to laboratory observations.
- Full Text:
- Date Issued: 1995
- Authors: Meiring, Leslie Frank
- Date: 1995
- Subjects: Science -- Study and teaching -- Research Science -- Study and teaching -- South Africa Science teachers -- Attitudes Science -- Philosoph
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1931 , http://hdl.handle.net/10962/d1007607
- Description: Many theories on the nature of science and the nature of learning have been proposed. In particular, two theoretical orientations have been identified as having a decisive impact on activities in the school science classroom, namely "Inductivism" and "Constructivism". Inductivism views observations as objective, facts as constants and knowledge as being obtained from a fixed external reality. The constructivist view sees all knowledge as "reality" reconstructed in the mind of the learner. Each view predisposes certain orientations towards the science curriculum and within it particularly to assessment. It is postulated that teachers' views on science will influence how they teach and assess it. An "inductivist" teacher is more likely to reward certain approved responses from learners whereas a "constructivist" teacher is more likely to attend to learners' unique observations as evidence of their thinking. In this study a questionnaire was developed in an attempt classify science teachers according to their views on the nature of science and learning, and during this process encourage them to reflect on these views. It is hoped that the instrument could measure any changes in teacher's views as a result of the teachers becoming more reflective practitioners over time. Research indicates that the majority of teachers have a predominantly inductivist view of science. The study confirmed the results of other researchers by showing that a majority of non-tertiary science educators could be classified as being strongly inductivist. However, the overall proportion of these teachers was not as high as expected. Of possible concern was the indication that the strongly constructivist group showed very strong inductivist tendencies when assessing written tests which involved pupils' responses to laboratory observations.
- Full Text:
- Date Issued: 1995
The expanding horizon : a geographical commentary upon routes, records, observations & opinions contained in selected documents concerning travel at the Cape, 1750-1800
- Forbes, Vernon S (Vernon Siegfried)
- Authors: Forbes, Vernon S (Vernon Siegfried)
- Date: 1958
- Subjects: Travelers -- South Africa , South Africa -- Description and travel -- Early works to 1800
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4886 , http://hdl.handle.net/10962/d1014908
- Description: This study seeks to provide a geographical commentary upon documents relating to travel in the Cape during the second half of the eighteenth century. These documents include not only books of travel, but also travel journals, letters and maps both published and unpublished. They have been examined in the first place to ascertain what light they throw on the evolution of geographical ideas concerning the phenomena now capable of classification under the broad heading of physical geography. Secondly the have been viewed as part of the geography of travel and exploration which deals with routes, the identification of places, the explanation of place-names and the evolution of the map, or in its absence, of the mental picture of the regions reported on. Historical events are also considered, for the geographer can no more afford to ignore history than the historian dare cast a blind eye upon geography.
- Full Text:
- Date Issued: 1958
- Authors: Forbes, Vernon S (Vernon Siegfried)
- Date: 1958
- Subjects: Travelers -- South Africa , South Africa -- Description and travel -- Early works to 1800
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4886 , http://hdl.handle.net/10962/d1014908
- Description: This study seeks to provide a geographical commentary upon documents relating to travel in the Cape during the second half of the eighteenth century. These documents include not only books of travel, but also travel journals, letters and maps both published and unpublished. They have been examined in the first place to ascertain what light they throw on the evolution of geographical ideas concerning the phenomena now capable of classification under the broad heading of physical geography. Secondly the have been viewed as part of the geography of travel and exploration which deals with routes, the identification of places, the explanation of place-names and the evolution of the map, or in its absence, of the mental picture of the regions reported on. Historical events are also considered, for the geographer can no more afford to ignore history than the historian dare cast a blind eye upon geography.
- Full Text:
- Date Issued: 1958
Modelling storm-time TEC changes using linear and non-linear techniques
- Authors: Uwamahoro, Jean Claude
- Date: 2019
- Subjects: Magnetic storms , Astronomy -- Computer programs , Imaging systems in astronomy , Ionospheric storms , Electrons -- Measurement , Magnetosphere -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92908 , vital:30762
- Description: Statistical models based on empirical orthogonal functions (EOF) analysis and non-linear regression analysis (NLRA) were developed for the purpose of estimating the ionospheric total electron content (TEC) during geomagnetic storms. The well-known least squares method (LSM) and Metropolis-Hastings algorithm (MHA) were used as optimization techniques to determine the unknown coefficients of the developed analytical expressions. Artificial Neural Networks (ANNs), the International Reference Ionosphere (IRI) model, and the Multi-Instrument Data Analysis System (MIDAS) tomographic inversion algorithm were also applied to storm-time TEC modelling/reconstruction for various latitudes of the African sector and surrounding areas. This work presents some of the first statistical modeling of the mid-latitude and low-latitude ionosphere during geomagnetic storms that includes solar, geomagnetic and neutral wind drivers.Development and validation of the empirical models were based on storm-time TEC data derived from the global positioning system (GPS) measurements over ground receivers within Africa and surrounding areas. The storm criterion applied was Dst 6 −50 nT and/or Kp > 4. The performance evaluation of MIDAS compared with ANNs to reconstruct storm-time TEC over the African low- and mid-latitude regions showed that MIDAS and ANNs provide comparable results. Their respective mean absolute error (MAE) values were 4.81 and 4.18 TECU. The ANN model was, however, found to perform 24.37 % better than MIDAS at estimating storm-time TEC for low latitudes, while MIDAS is 13.44 % more accurate than ANN for the mid-latitudes. When their performances are compared with the IRI model, both MIDAS and ANN model were found to provide more accurate storm-time TEC reconstructions for the African low- and mid-latitude regions. A comparative study of the performances of EOF, NLRA, ANN, and IRI models to estimate TEC during geomagnetic storm conditions over various latitudes showed that the ANN model is about 10 %, 26 %, and 58 % more accurate than EOF, NLRA, and IRI models, respectively, while EOF was found to perform 15 %, and 44 % better than NLRA and IRI, respectively. It was further found that the NLRA model is 25 % more accurate than the IRI model. We have also investigated for the first time, the role of meridional neutral winds (from the Horizontal Wind Model) to storm-time TEC modelling in the low latitude, northern and southern hemisphere mid-latitude regions of the African sector, based on ANN models. Statistics have shown that the inclusion of the meridional wind velocity in TEC modelling during geomagnetic storms leads to percentage improvements of about 5 % for the low latitude, 10 % and 5 % for the northern and southern hemisphere mid-latitude regions, respectively. High-latitude storm-induced winds and the inter-hemispheric blows of the meridional winds from summer to winter hemisphere have been suggested to be associated with these improvements.
- Full Text:
- Date Issued: 2019
- Authors: Uwamahoro, Jean Claude
- Date: 2019
- Subjects: Magnetic storms , Astronomy -- Computer programs , Imaging systems in astronomy , Ionospheric storms , Electrons -- Measurement , Magnetosphere -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92908 , vital:30762
- Description: Statistical models based on empirical orthogonal functions (EOF) analysis and non-linear regression analysis (NLRA) were developed for the purpose of estimating the ionospheric total electron content (TEC) during geomagnetic storms. The well-known least squares method (LSM) and Metropolis-Hastings algorithm (MHA) were used as optimization techniques to determine the unknown coefficients of the developed analytical expressions. Artificial Neural Networks (ANNs), the International Reference Ionosphere (IRI) model, and the Multi-Instrument Data Analysis System (MIDAS) tomographic inversion algorithm were also applied to storm-time TEC modelling/reconstruction for various latitudes of the African sector and surrounding areas. This work presents some of the first statistical modeling of the mid-latitude and low-latitude ionosphere during geomagnetic storms that includes solar, geomagnetic and neutral wind drivers.Development and validation of the empirical models were based on storm-time TEC data derived from the global positioning system (GPS) measurements over ground receivers within Africa and surrounding areas. The storm criterion applied was Dst 6 −50 nT and/or Kp > 4. The performance evaluation of MIDAS compared with ANNs to reconstruct storm-time TEC over the African low- and mid-latitude regions showed that MIDAS and ANNs provide comparable results. Their respective mean absolute error (MAE) values were 4.81 and 4.18 TECU. The ANN model was, however, found to perform 24.37 % better than MIDAS at estimating storm-time TEC for low latitudes, while MIDAS is 13.44 % more accurate than ANN for the mid-latitudes. When their performances are compared with the IRI model, both MIDAS and ANN model were found to provide more accurate storm-time TEC reconstructions for the African low- and mid-latitude regions. A comparative study of the performances of EOF, NLRA, ANN, and IRI models to estimate TEC during geomagnetic storm conditions over various latitudes showed that the ANN model is about 10 %, 26 %, and 58 % more accurate than EOF, NLRA, and IRI models, respectively, while EOF was found to perform 15 %, and 44 % better than NLRA and IRI, respectively. It was further found that the NLRA model is 25 % more accurate than the IRI model. We have also investigated for the first time, the role of meridional neutral winds (from the Horizontal Wind Model) to storm-time TEC modelling in the low latitude, northern and southern hemisphere mid-latitude regions of the African sector, based on ANN models. Statistics have shown that the inclusion of the meridional wind velocity in TEC modelling during geomagnetic storms leads to percentage improvements of about 5 % for the low latitude, 10 % and 5 % for the northern and southern hemisphere mid-latitude regions, respectively. High-latitude storm-induced winds and the inter-hemispheric blows of the meridional winds from summer to winter hemisphere have been suggested to be associated with these improvements.
- Full Text:
- Date Issued: 2019
Speech at inaugural East London graduation ceremony
- Authors: Henderson, Derek Scott
- Date: 1987-05-09
- Language: English
- Type: Text
- Identifier: vital:7563 , http://hdl.handle.net/10962/d1018440
- Full Text:
- Date Issued: 1987-05-09
- Authors: Henderson, Derek Scott
- Date: 1987-05-09
- Language: English
- Type: Text
- Identifier: vital:7563 , http://hdl.handle.net/10962/d1018440
- Full Text:
- Date Issued: 1987-05-09
Aspects of reality as reflected by the human form in painting
- Authors: Fourie, F T
- Date: 1966
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:21174 , http://hdl.handle.net/10962/6739
- Full Text:
- Date Issued: 1966
- Authors: Fourie, F T
- Date: 1966
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:21174 , http://hdl.handle.net/10962/6739
- Full Text:
- Date Issued: 1966
Evaluating the physiological, morphological and nutritional effects of elevated atmospheric CO2 and drought on select South African maize cultivars
- Authors: Bopape, Tebadi Mamadiga
- Date: 2021-10
- Subjects: Corn Varieties South Africa , Dry farming South Africa , Corn Effect of atmospheric carbon dioxide on South Africa , Corn Effect of drought on South Africa , Corn Morphology , Corn Nutrition , Corn Physiological effect
- Language: English
- Type: Master theses , text
- Identifier: http://hdl.handle.net/10962/189020 , vital:44807
- Description: Thesis embargoed. Expected Release date October 2022. , Thesis (MSc) -- Faculty of Science, Botany, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Bopape, Tebadi Mamadiga
- Date: 2021-10
- Subjects: Corn Varieties South Africa , Dry farming South Africa , Corn Effect of atmospheric carbon dioxide on South Africa , Corn Effect of drought on South Africa , Corn Morphology , Corn Nutrition , Corn Physiological effect
- Language: English
- Type: Master theses , text
- Identifier: http://hdl.handle.net/10962/189020 , vital:44807
- Description: Thesis embargoed. Expected Release date October 2022. , Thesis (MSc) -- Faculty of Science, Botany, 2021
- Full Text:
- Date Issued: 2021-10
“Savage” hair and mothers’ hearts: a corpus-based critical discourse analysis of intersectional identities in two South African school setworks
- Hubbard, Beatrice Elizabeth Anne
- Authors: Hubbard, Beatrice Elizabeth Anne
- Date: 2020
- Subjects: Women in literature , Women, Black in literature , Critical discourse analysis , Magona, Sindiwe -- Mother to mother , Bulbring, Edyth -- The Mark
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/141770 , vital:38003
- Description: This thesis reports on the discursive construal of intersectional physical identities, with particular reference to ‘black’ female characters, in two novels: Sindiwe Magona’s Mother to Mother, and Edyth Bulbring’s The Mark. These novels are prescribed for Grade 10 English Home Language learners in all South African public schools. Gendered identity construction in texts has been widely discussed in critical linguistics, with some research showing that the ways in which bodies are construed reveal the hegemonic and stereotypical gendering of men and women. However, these arguments have not adequately addressed the intersectional nature of identity construction. This thesis employs Corpus-based Critical Discourse Analysis to investigate the complex physical identities of, especially, ‘black’ female characters in these two novels. The inclusion of Corpus Linguistics is essential for uncovering hidden patterns of language choice, while the analytical techniques and theoretical notions from Critical Discourse Analysis provide the explanatory power that underpins the qualitative analysis. The uses to which nine key body parts are put reveal discourse prosodies showing different intersectional realisations for intimacy, power, violence, emotion, and racial marking. These discourse prosodies are most starkly realised in the two body parts, one from each novel, that are statistically most clearly linked to ‘black’ female characters. HAIR in The Mark is used variously as a racial marker, a target for racism, and a symbol for racial pride. HEART in Mother to Mother is used almost exclusively to symbolise the emotional pain of a mother’s love, and how empathy for another mother’s pain can bridge racial divides. Principal findings reveal that both novels provide very necessary lessons in cross-racial empathy, pride in ‘blackness,’ and interracial relationships. However, it is of concern that these novels also exhibit an over-valorisation of motherhood, largely stereotypical depictions of gender roles, and ableist language. In sum, both novels promote some of the transformative principles of the national curriculum, and are shown to have a bearing on nation building.
- Full Text:
- Date Issued: 2020
- Authors: Hubbard, Beatrice Elizabeth Anne
- Date: 2020
- Subjects: Women in literature , Women, Black in literature , Critical discourse analysis , Magona, Sindiwe -- Mother to mother , Bulbring, Edyth -- The Mark
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/141770 , vital:38003
- Description: This thesis reports on the discursive construal of intersectional physical identities, with particular reference to ‘black’ female characters, in two novels: Sindiwe Magona’s Mother to Mother, and Edyth Bulbring’s The Mark. These novels are prescribed for Grade 10 English Home Language learners in all South African public schools. Gendered identity construction in texts has been widely discussed in critical linguistics, with some research showing that the ways in which bodies are construed reveal the hegemonic and stereotypical gendering of men and women. However, these arguments have not adequately addressed the intersectional nature of identity construction. This thesis employs Corpus-based Critical Discourse Analysis to investigate the complex physical identities of, especially, ‘black’ female characters in these two novels. The inclusion of Corpus Linguistics is essential for uncovering hidden patterns of language choice, while the analytical techniques and theoretical notions from Critical Discourse Analysis provide the explanatory power that underpins the qualitative analysis. The uses to which nine key body parts are put reveal discourse prosodies showing different intersectional realisations for intimacy, power, violence, emotion, and racial marking. These discourse prosodies are most starkly realised in the two body parts, one from each novel, that are statistically most clearly linked to ‘black’ female characters. HAIR in The Mark is used variously as a racial marker, a target for racism, and a symbol for racial pride. HEART in Mother to Mother is used almost exclusively to symbolise the emotional pain of a mother’s love, and how empathy for another mother’s pain can bridge racial divides. Principal findings reveal that both novels provide very necessary lessons in cross-racial empathy, pride in ‘blackness,’ and interracial relationships. However, it is of concern that these novels also exhibit an over-valorisation of motherhood, largely stereotypical depictions of gender roles, and ableist language. In sum, both novels promote some of the transformative principles of the national curriculum, and are shown to have a bearing on nation building.
- Full Text:
- Date Issued: 2020
The wreck of the Dutch man o' war, Amsterdam, in December 1817 on the Eastern Cape coast of Southern Africa: an elucidation of the literary and material remains with an annotated translation of the Journal of Captain Hermanus Hofmeijer (1814-1818)
- Authors: Bennie, Jennifer Shirley
- Date: 1998
- Subjects: Amsterdam (Steamship) , Shipwrecks -- South Africa , Underwater archaeology , Nederlandsche Oost-Indische Compagnie , Hofmeijer, Hermanus, 1721-1805--Diaries , Voyages and travels -- History -- 18th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2533 , http://hdl.handle.net/10962/d1002385 , Amsterdam (Steamship) , Shipwrecks -- South Africa , Underwater archaeology , Nederlandsche Oost-Indische Compagnie , Hofmeijer, Hermanus, 1721-1805--Diaries , Voyages and travels -- History -- 18th century
- Description: This study endeavours to elucidate the journal of Captain Hermanus Hofmeijer of the Dutch man 0' war, Amsterdam, which has been transcribed from the original script, translated from Dutch into English and interpreted from a contemporary viewpoint. It offers an opportunity to evaluate a unique primary historical document which records an important historical event. An attempt has been made to contextualise the incident in the light of the early history of the Dutch people. The contribution of the Dutch East India Company (VaC) to the trade and commerce of the Netherlands during the 17th and 18th centuries has been assessed together with the shipbuilding techniques that served to make the Dutch a major seafaring nation. The significance of Texel and Nieuwediep has been examined and the sea route and navigational instruments placed in perspective. The voyage has been analysed in some detail. The background of Captain Hermanus Hofmeijer has proved especially interesting. Although he pursued his career with the Dutch Navy, he was born and spent his early years in Cape Town, South Africa. The time spent by the Amsterdam in Batavia, Samaraog and Sourabaya gives an insight into the Dutch possessions overseas. The return voyage, storms and ultimate grounding are of special interest as Hofmeijer records the journey and events on a daily basis. The impact and significance of 217 extra people in the Eastern Cape area did not go unnoticed, and although the event was not well documented, an attempt at some contextualisation has been made. Finally a short overview of maritime archaeology in South Africa and its significance as a relatively new discipline has been included. The study of the material remains of the wreck of the Amsterdam has resulted in a new understanding of wooden ships built in the early 19th century.
- Full Text:
- Date Issued: 1998
- Authors: Bennie, Jennifer Shirley
- Date: 1998
- Subjects: Amsterdam (Steamship) , Shipwrecks -- South Africa , Underwater archaeology , Nederlandsche Oost-Indische Compagnie , Hofmeijer, Hermanus, 1721-1805--Diaries , Voyages and travels -- History -- 18th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2533 , http://hdl.handle.net/10962/d1002385 , Amsterdam (Steamship) , Shipwrecks -- South Africa , Underwater archaeology , Nederlandsche Oost-Indische Compagnie , Hofmeijer, Hermanus, 1721-1805--Diaries , Voyages and travels -- History -- 18th century
- Description: This study endeavours to elucidate the journal of Captain Hermanus Hofmeijer of the Dutch man 0' war, Amsterdam, which has been transcribed from the original script, translated from Dutch into English and interpreted from a contemporary viewpoint. It offers an opportunity to evaluate a unique primary historical document which records an important historical event. An attempt has been made to contextualise the incident in the light of the early history of the Dutch people. The contribution of the Dutch East India Company (VaC) to the trade and commerce of the Netherlands during the 17th and 18th centuries has been assessed together with the shipbuilding techniques that served to make the Dutch a major seafaring nation. The significance of Texel and Nieuwediep has been examined and the sea route and navigational instruments placed in perspective. The voyage has been analysed in some detail. The background of Captain Hermanus Hofmeijer has proved especially interesting. Although he pursued his career with the Dutch Navy, he was born and spent his early years in Cape Town, South Africa. The time spent by the Amsterdam in Batavia, Samaraog and Sourabaya gives an insight into the Dutch possessions overseas. The return voyage, storms and ultimate grounding are of special interest as Hofmeijer records the journey and events on a daily basis. The impact and significance of 217 extra people in the Eastern Cape area did not go unnoticed, and although the event was not well documented, an attempt at some contextualisation has been made. Finally a short overview of maritime archaeology in South Africa and its significance as a relatively new discipline has been included. The study of the material remains of the wreck of the Amsterdam has resulted in a new understanding of wooden ships built in the early 19th century.
- Full Text:
- Date Issued: 1998
The dynamics of an emerging outcomes-based educational approach in a second language English classroom
- Authors: Westphal, Vivian
- Date: 2000
- Subjects: English language -- Study and teaching -- Foreign speakers -- South Africa Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1502 , http://hdl.handle.net/10962/d1003384
- Description: Curriculum 2005 and outcomes-based education was introduced to South African educators in 1996 by the Minister of Education, Prof. S.M.E. Bengu as an alternative to the racially divided education system prior to the first democratic elections of 1995. The new curriculum was designed to transform the education system into a more equitable system by focussing on creating learners who would become creative thinkers, independent, productive workers and responsible, non-racial citizens. Learners would take a greater role in their own education and teachers would take on new roles as facilitators in the learning process. The new approach was introduced into grade 1 in 1998 and grade 2 in 1999. By using a modified ethnographic approach, this research project studies how one teacher has begun to think about Curriculum 2005 and implement an OBE approach to ESL teaching in a grade 2 classroom. It also focuses on gaining insights into how the teacher has attempted to make sense of the new curriculum in terms of her current practice and the training she has received in OBE. The ethnographic approach of the thesis has allowed the researcher to draw on many forms of data providing a holistic view. Tentative findings show that the teacher is experiencing difficulty in “unpacking” the underlying principles of OBE in terms of her current methods of teaching ESL. She continues to work from tacit knowledge. Because she has received very little training in OBE, she lacks the tools to become a more reflective practitioner. Despite this, her ESL lessons show a positive communicative approach to language teaching by focusing on stories, rhymes and songs as comprehensible input for the learners. The findings of this thesis tentatively suggest that unless teachers are given more adequate training and learning support materials, their classroom practices will remain relatively unchanged.
- Full Text:
- Date Issued: 2000
- Authors: Westphal, Vivian
- Date: 2000
- Subjects: English language -- Study and teaching -- Foreign speakers -- South Africa Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1502 , http://hdl.handle.net/10962/d1003384
- Description: Curriculum 2005 and outcomes-based education was introduced to South African educators in 1996 by the Minister of Education, Prof. S.M.E. Bengu as an alternative to the racially divided education system prior to the first democratic elections of 1995. The new curriculum was designed to transform the education system into a more equitable system by focussing on creating learners who would become creative thinkers, independent, productive workers and responsible, non-racial citizens. Learners would take a greater role in their own education and teachers would take on new roles as facilitators in the learning process. The new approach was introduced into grade 1 in 1998 and grade 2 in 1999. By using a modified ethnographic approach, this research project studies how one teacher has begun to think about Curriculum 2005 and implement an OBE approach to ESL teaching in a grade 2 classroom. It also focuses on gaining insights into how the teacher has attempted to make sense of the new curriculum in terms of her current practice and the training she has received in OBE. The ethnographic approach of the thesis has allowed the researcher to draw on many forms of data providing a holistic view. Tentative findings show that the teacher is experiencing difficulty in “unpacking” the underlying principles of OBE in terms of her current methods of teaching ESL. She continues to work from tacit knowledge. Because she has received very little training in OBE, she lacks the tools to become a more reflective practitioner. Despite this, her ESL lessons show a positive communicative approach to language teaching by focusing on stories, rhymes and songs as comprehensible input for the learners. The findings of this thesis tentatively suggest that unless teachers are given more adequate training and learning support materials, their classroom practices will remain relatively unchanged.
- Full Text:
- Date Issued: 2000
Synthesis, characterisation and biological evaluation of novel anti-infective compounds bearing ferrocene, arylpyrrole, thiazolidinedione, quinoline and triazole moieties
- Authors: Oderinlo, Ogunyemi Olajide
- Date: 2019
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/114714 , vital:34016 , 10.21504/10962/114714
- Description: Expected release date-April 2022
- Full Text: false
- Date Issued: 2019
- Authors: Oderinlo, Ogunyemi Olajide
- Date: 2019
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/114714 , vital:34016 , 10.21504/10962/114714
- Description: Expected release date-April 2022
- Full Text: false
- Date Issued: 2019
Assessing the genetic diversity of catface rockcod epinephelus andersoni in the subtropical Western Indian Ocean and modelling the effects of climate change on their distribution
- Authors: Coppinger, Christine Rose
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54499 , vital:26570
- Description: The catface rockcod Epinephelus andersoni is a range-restricted species that is endemic to the southeast coast of Africa from Quissico in Mozambique (subtropical) to Knysna in South Africa (warmtemperate). Its complex life-history, long-lived nature and high residency make E. andersoni potentially vulnerable to over-exploitation. Epinephelus andersoni is an important fishery species and has shown signs of depletion. Due to inadequate information necessary for management and conservation, further research is vital, particularly in the face of potentially significant climatic changes which could put further pressure on E. andersoni. The aim of the study was to provide information for the management of E. andersoni, with considerations for the possibly detrimental effects of future climate change. The objectives of this study were to describe the genetic structure and diversity of E. andersoni and to determine possible range shifts of E. andersoni with future changes in sea surface temperature. Genetic samples were collected throughout the distribution of E. andersoni. Standard DNA extraction and PCR using universal primers were conducted and nuclear (RPS7-1) and mitochondrial (cytochrome b) data were analysed to determine genetic diversity. A combination of nuclear and mitochondrial markers was used to ensure that the results were robust. RPS7-1 haplotype diversity was high (0.801) and an AMOVA on the RPS7-1 data showed significantly high among group variation (ΦCT = 0.204, p < 0.05) between five groups: 1. Quissico to Inhaca; 2. Cape Vidal to Port Edward; 3 Port St Johns to Coffee Bay; 4. Mbashe; 5. Port Alfred. This geographic structuring could be attributed to low gene flow across barriers such as the Port Alfred upwelling cell, the Mozambique Channel eddies and smaller more localised upwelling cells such as the Port St Johns cell. The cytochrome b results contrastingly indicate low haplotype diversity (0.309) and no differentiation (ΦCT = 0.265, p = 0.074) between groups and support the hypothesis of a historical population bottleneck. This may be due to an unusually slower mutation rate of the cytochrome b region than the RPS7-1 region, resulting in the RPS7-1 data showing a more recent picture of diversification. To complement the genetic results, niche modelling techniques were used to determine range shifts of E. andersoni with future temperature trends using species distribution and climatic data. The model illustrated a contraction of the E. andersoni distribution as well as future intensification of various upwelling cells along the south-east African coast including the Port Alfred upwelling cell. Due to the low gene flow across these barriers this intensification could decrease the resilience of E. andersoni, as its range becomes more limited with global change. The genetic data and modelling results combined provide useful information on which to base future fisheries management.
- Full Text:
- Date Issued: 2014
- Authors: Coppinger, Christine Rose
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54499 , vital:26570
- Description: The catface rockcod Epinephelus andersoni is a range-restricted species that is endemic to the southeast coast of Africa from Quissico in Mozambique (subtropical) to Knysna in South Africa (warmtemperate). Its complex life-history, long-lived nature and high residency make E. andersoni potentially vulnerable to over-exploitation. Epinephelus andersoni is an important fishery species and has shown signs of depletion. Due to inadequate information necessary for management and conservation, further research is vital, particularly in the face of potentially significant climatic changes which could put further pressure on E. andersoni. The aim of the study was to provide information for the management of E. andersoni, with considerations for the possibly detrimental effects of future climate change. The objectives of this study were to describe the genetic structure and diversity of E. andersoni and to determine possible range shifts of E. andersoni with future changes in sea surface temperature. Genetic samples were collected throughout the distribution of E. andersoni. Standard DNA extraction and PCR using universal primers were conducted and nuclear (RPS7-1) and mitochondrial (cytochrome b) data were analysed to determine genetic diversity. A combination of nuclear and mitochondrial markers was used to ensure that the results were robust. RPS7-1 haplotype diversity was high (0.801) and an AMOVA on the RPS7-1 data showed significantly high among group variation (ΦCT = 0.204, p < 0.05) between five groups: 1. Quissico to Inhaca; 2. Cape Vidal to Port Edward; 3 Port St Johns to Coffee Bay; 4. Mbashe; 5. Port Alfred. This geographic structuring could be attributed to low gene flow across barriers such as the Port Alfred upwelling cell, the Mozambique Channel eddies and smaller more localised upwelling cells such as the Port St Johns cell. The cytochrome b results contrastingly indicate low haplotype diversity (0.309) and no differentiation (ΦCT = 0.265, p = 0.074) between groups and support the hypothesis of a historical population bottleneck. This may be due to an unusually slower mutation rate of the cytochrome b region than the RPS7-1 region, resulting in the RPS7-1 data showing a more recent picture of diversification. To complement the genetic results, niche modelling techniques were used to determine range shifts of E. andersoni with future temperature trends using species distribution and climatic data. The model illustrated a contraction of the E. andersoni distribution as well as future intensification of various upwelling cells along the south-east African coast including the Port Alfred upwelling cell. Due to the low gene flow across these barriers this intensification could decrease the resilience of E. andersoni, as its range becomes more limited with global change. The genetic data and modelling results combined provide useful information on which to base future fisheries management.
- Full Text:
- Date Issued: 2014
Rhodeo: 1992 - May
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14773 , http://hdl.handle.net/10962/d1019645
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text: false
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14773 , http://hdl.handle.net/10962/d1019645
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text: false
The use of hydrological information to improve flood management-integrated hydrological modelling of the Zambezi River basin
- Vilanculos, Agostinho Chuquelane Fadulo
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
The extent of urban Green Collar employment, its contribution to poverty alleviation and potential for growth in the Eastern Cape, South Africa
- Authors: King, Andrew
- Date: 2019
- Subjects: Economic development -- Environmental aspects -- South Africa -- Eastern Cape , Poverty prevention -- South Africa -- Eastern Cape , Job creation -- South Africa -- Eastern Cape , Urban ecology (Sociology) -- South Africa -- Eastern Cape , Urban poor -- Employment -- South Africa -- Eastern Cape , Clean energy industries -- Employment -- South Africa -- Eastern Cape , Renewable energy sources -- Government policy -- South Africa -- Eastern Cape , Land use, Urban -- South Africa -- Eastern Cape , Open spaces -- Environmental aspects -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/115191 , vital:34095
- Description: The aim of this research was to investigate the job provisioning benefits of urban green space (GS), the ability of these jobs to alleviate poverty amongst poor urban households, as well as the potential to increase the number of Green Collar (GC) jobs. According to Lal et al. (2010), Roy et al. (2012) and others, environmental employment or GC jobs, represent the very synergy between social, economic and environmental resilience and sustainability, and have the ability to provide an additional range of goods and services. Data was collected from 12 towns and cities in the Eastern Cape of South Africa, all varying in population, town size and geographic location. Structured employer, employee and resident interviews were used to collect data, which pertained to a number of employment characteristics and employee living conditions. Throughout the sample, 19 different types of jobs were identified, and a total of 17 429 GC employees were counted, sharing a total of approximately R503 million in annual wages. Some GC employees were found to still be in a position of poverty despite employment, while others enjoyed a higher standard of living as a result, although this was largely dependent on the extent of wages and other household and employment attributes. Using lessons learnt from previous chapters, a number of data sources and a creative approach, the potential for growth and improvement in the urban GC sector was discussed, and the way forward involves private, public, informal and civil sector participation and innovation; which will not only enhance environmental and social ecosystem services, but also provide meaningful employment opportunities to the otherwise impoverished. Urban GC jobs should be widely viewed as a useful tool in achieving social, environmental and economic prosperity in urban landscapes (Bowen and Kuralbayeva, 2015).
- Full Text:
- Date Issued: 2019
- Authors: King, Andrew
- Date: 2019
- Subjects: Economic development -- Environmental aspects -- South Africa -- Eastern Cape , Poverty prevention -- South Africa -- Eastern Cape , Job creation -- South Africa -- Eastern Cape , Urban ecology (Sociology) -- South Africa -- Eastern Cape , Urban poor -- Employment -- South Africa -- Eastern Cape , Clean energy industries -- Employment -- South Africa -- Eastern Cape , Renewable energy sources -- Government policy -- South Africa -- Eastern Cape , Land use, Urban -- South Africa -- Eastern Cape , Open spaces -- Environmental aspects -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/115191 , vital:34095
- Description: The aim of this research was to investigate the job provisioning benefits of urban green space (GS), the ability of these jobs to alleviate poverty amongst poor urban households, as well as the potential to increase the number of Green Collar (GC) jobs. According to Lal et al. (2010), Roy et al. (2012) and others, environmental employment or GC jobs, represent the very synergy between social, economic and environmental resilience and sustainability, and have the ability to provide an additional range of goods and services. Data was collected from 12 towns and cities in the Eastern Cape of South Africa, all varying in population, town size and geographic location. Structured employer, employee and resident interviews were used to collect data, which pertained to a number of employment characteristics and employee living conditions. Throughout the sample, 19 different types of jobs were identified, and a total of 17 429 GC employees were counted, sharing a total of approximately R503 million in annual wages. Some GC employees were found to still be in a position of poverty despite employment, while others enjoyed a higher standard of living as a result, although this was largely dependent on the extent of wages and other household and employment attributes. Using lessons learnt from previous chapters, a number of data sources and a creative approach, the potential for growth and improvement in the urban GC sector was discussed, and the way forward involves private, public, informal and civil sector participation and innovation; which will not only enhance environmental and social ecosystem services, but also provide meaningful employment opportunities to the otherwise impoverished. Urban GC jobs should be widely viewed as a useful tool in achieving social, environmental and economic prosperity in urban landscapes (Bowen and Kuralbayeva, 2015).
- Full Text:
- Date Issued: 2019
Welcome address at the Southern Africa-Nordic Centre Conference
- Authors: Badat, Saleem
- Date: 2009-12-07
- Language: English
- Type: Text
- Identifier: vital:7736 , http://hdl.handle.net/10962/d1015883
- Full Text:
- Date Issued: 2009-12-07
- Authors: Badat, Saleem
- Date: 2009-12-07
- Language: English
- Type: Text
- Identifier: vital:7736 , http://hdl.handle.net/10962/d1015883
- Full Text:
- Date Issued: 2009-12-07
Enhancing the saccharolytic phase of sugar beet pulp via hemicellulase synergy
- Authors: Dredge, Roselyn Ann
- Date: 2010
- Subjects: Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3955 , http://hdl.handle.net/10962/d1004014 , Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Description: The sugar beet (Beta vulgaris) plant has in recent years been added to the Biofuel Industrial Strategy (Department of Minerals and Energy, 2007) by the South African government as a crop grown for the production of bio-ethanol. Sugar beet is commonly grown in Europe for the production of sucrose and has recently been cultivated in Cradock and the surrounding areas (Engineering News, 2008). The biofuel industry usually ferments the sucrose with Saccharomyces cerevisiae to yield bio-ethanol. However, researchers are presented with a critical role to increase current yields as there are concerns over the process costs from industrial biotechnologists. The beet factories produce a pulp by-product removed of all sucrose. The hemicellulose-rich pulp can be degraded by microbial enzymes to simple sugars that can be subsequently fermented to bio-ethanol. Thus, the pulp represents a potential source for second generation biofuel. The process of utilising microbial hemicellulases requires an initial chemical pre-treatment step to delignify the sugar beet pulp (SBP). An alkaline pre-treatment with ‘slake lime’ (calcium hydroxide) was investigated using a 23 factorial design and the factors examined were: lime load; temperature and time. The analysed results showed the highest release of reducing sugars at the pre-treatment conditions of: 0.4 g lime / g SBP; 40°C and 36 hours. A partial characterisation of the Clostridium cellulovorans hemicellulases was carried out to verify the optimal activity conditions stated in literature. The highest release of reducing sugars was measured at pH 6.5 – 7.0 and at 45°C for arabinofuranosidase A (ArfA); at pH 5.5 and 40°C for mannanase A (ManA) and pH 5.0 – 6.0 and 45°C for xylanase A (XynA). Temperature studies showed that a complete loss of enzymatic activity occurred after 11 hours for ManA; and 84-96 hours for ArfA. XynA was still active after 120 hours. The optimised lime pre-treated SBP was subsequently degraded using various combinations and percentages of C. cellulovorans ArfA, ManA and XynA to determine the maximal release of reducing sugars. Synergistically, the highest synergy was observed at 75% ArfA and 25% ManA, with a specific activity of 2.9 μmol/min/g protein. However, the highest release of sugars was observed at 4.2 μmol/min/g protein at 100% ArfA. This study has initiated the research within South Africa on SBP and its degradation by C. cellulovorans. Preliminary studies show that SBP has the potential to be utilised as a second generation biofuel source.
- Full Text:
- Date Issued: 2010
- Authors: Dredge, Roselyn Ann
- Date: 2010
- Subjects: Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3955 , http://hdl.handle.net/10962/d1004014 , Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Description: The sugar beet (Beta vulgaris) plant has in recent years been added to the Biofuel Industrial Strategy (Department of Minerals and Energy, 2007) by the South African government as a crop grown for the production of bio-ethanol. Sugar beet is commonly grown in Europe for the production of sucrose and has recently been cultivated in Cradock and the surrounding areas (Engineering News, 2008). The biofuel industry usually ferments the sucrose with Saccharomyces cerevisiae to yield bio-ethanol. However, researchers are presented with a critical role to increase current yields as there are concerns over the process costs from industrial biotechnologists. The beet factories produce a pulp by-product removed of all sucrose. The hemicellulose-rich pulp can be degraded by microbial enzymes to simple sugars that can be subsequently fermented to bio-ethanol. Thus, the pulp represents a potential source for second generation biofuel. The process of utilising microbial hemicellulases requires an initial chemical pre-treatment step to delignify the sugar beet pulp (SBP). An alkaline pre-treatment with ‘slake lime’ (calcium hydroxide) was investigated using a 23 factorial design and the factors examined were: lime load; temperature and time. The analysed results showed the highest release of reducing sugars at the pre-treatment conditions of: 0.4 g lime / g SBP; 40°C and 36 hours. A partial characterisation of the Clostridium cellulovorans hemicellulases was carried out to verify the optimal activity conditions stated in literature. The highest release of reducing sugars was measured at pH 6.5 – 7.0 and at 45°C for arabinofuranosidase A (ArfA); at pH 5.5 and 40°C for mannanase A (ManA) and pH 5.0 – 6.0 and 45°C for xylanase A (XynA). Temperature studies showed that a complete loss of enzymatic activity occurred after 11 hours for ManA; and 84-96 hours for ArfA. XynA was still active after 120 hours. The optimised lime pre-treated SBP was subsequently degraded using various combinations and percentages of C. cellulovorans ArfA, ManA and XynA to determine the maximal release of reducing sugars. Synergistically, the highest synergy was observed at 75% ArfA and 25% ManA, with a specific activity of 2.9 μmol/min/g protein. However, the highest release of sugars was observed at 4.2 μmol/min/g protein at 100% ArfA. This study has initiated the research within South Africa on SBP and its degradation by C. cellulovorans. Preliminary studies show that SBP has the potential to be utilised as a second generation biofuel source.
- Full Text:
- Date Issued: 2010
Aspects of the biology and population dynamics of the geelbek Atractoscion aequidens (Cuvier) (Pisces: Sciaenidae) off the South African coast
- Authors: Griffiths, Marc H
- Date: 1988
- Subjects: Sciaenidae -- South Africa Fish populations -- South Africa Atractoscion Atractoscion -- South Africa -- Ecology Atractoscion -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5194 , http://hdl.handle.net/10962/d1001970
- Description: The geelbek Atractoscion aeguidens is an important commercial and recreational linefish species along the South African eastern seaboard . Aspects of its biology and population dynamics were investigated using data collected from various sampling sites along the South African east coast and from catch statistics obtained from both the Sea Fisheries Research Institute (Cape Town), and dealer records. The biological aspects studied included age and growth, reproduction and feeding. It was established that A. aeguidens is a fast growing species with a relatively late age at sexual maturity and a 1:1 sex ratio. Feeding studies revealed that it has become specialized to feed on small pelagic fish. The South African geelbek stock consists of three distinct age related sub-populations, each representing a particular phase in the life cycle. The sub-adults (1-4 yrs) occur in the South West Cape and feed predominantly on anchovy, Engraulis capensis, which they follow, moving inshore in summer and offshore in winter. The adults (5-9 yrs) undergo a seasonal inshore migration to Natal where they spawn in spring. The dynamics of this migration are strongly influenced by the annual movement of their principal prey viz. , Sardinops ocellatus, to that region. As a result the geelbek first arrive in Natal during mid winter. Evidence is also presented to suggest that a significant number of "adolescent " fish (4-5 yrs) undergo limited gonad maturation and a partial migration to at least as far as the South East Cape. Spawning appears to occur offshore. It is postulated that eggs and larvae are transported southwards by the peripheral waters of the Agulhas Current. After spawning the adults probably remain offshore and use the current to aid their return to the South and South West Cape, where they spend summer feeding on the Agulhas Bank. Juveniles (<1 yr) first appear in the South East Cape between January and March. They apparently use this region as a nursery area for almost a year before moving southwards to join the sub-adults in the South West Cape. In the South East Cape, the juveniles feed initially on mysids whereafter they switch to anchovies and pilchards. A preliminary stock assessment using yield per recruit and spawner biomass per recruit models, indicated that despite the current legislation the South African geelbek population is already overexploited. This is largely attributed to high rates of fishing mortality of the migratory adult population. Further management recommendations are therefore proposed. These include a size limit (660 mm FL), derived from an investigation of the interrelationship between natural mortality and somatic growth in a theoretical unexploited cohort, as well as a uniform bag limit for all user groups (5 fish per person per day)
- Full Text:
- Date Issued: 1988
- Authors: Griffiths, Marc H
- Date: 1988
- Subjects: Sciaenidae -- South Africa Fish populations -- South Africa Atractoscion Atractoscion -- South Africa -- Ecology Atractoscion -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5194 , http://hdl.handle.net/10962/d1001970
- Description: The geelbek Atractoscion aeguidens is an important commercial and recreational linefish species along the South African eastern seaboard . Aspects of its biology and population dynamics were investigated using data collected from various sampling sites along the South African east coast and from catch statistics obtained from both the Sea Fisheries Research Institute (Cape Town), and dealer records. The biological aspects studied included age and growth, reproduction and feeding. It was established that A. aeguidens is a fast growing species with a relatively late age at sexual maturity and a 1:1 sex ratio. Feeding studies revealed that it has become specialized to feed on small pelagic fish. The South African geelbek stock consists of three distinct age related sub-populations, each representing a particular phase in the life cycle. The sub-adults (1-4 yrs) occur in the South West Cape and feed predominantly on anchovy, Engraulis capensis, which they follow, moving inshore in summer and offshore in winter. The adults (5-9 yrs) undergo a seasonal inshore migration to Natal where they spawn in spring. The dynamics of this migration are strongly influenced by the annual movement of their principal prey viz. , Sardinops ocellatus, to that region. As a result the geelbek first arrive in Natal during mid winter. Evidence is also presented to suggest that a significant number of "adolescent " fish (4-5 yrs) undergo limited gonad maturation and a partial migration to at least as far as the South East Cape. Spawning appears to occur offshore. It is postulated that eggs and larvae are transported southwards by the peripheral waters of the Agulhas Current. After spawning the adults probably remain offshore and use the current to aid their return to the South and South West Cape, where they spend summer feeding on the Agulhas Bank. Juveniles (<1 yr) first appear in the South East Cape between January and March. They apparently use this region as a nursery area for almost a year before moving southwards to join the sub-adults in the South West Cape. In the South East Cape, the juveniles feed initially on mysids whereafter they switch to anchovies and pilchards. A preliminary stock assessment using yield per recruit and spawner biomass per recruit models, indicated that despite the current legislation the South African geelbek population is already overexploited. This is largely attributed to high rates of fishing mortality of the migratory adult population. Further management recommendations are therefore proposed. These include a size limit (660 mm FL), derived from an investigation of the interrelationship between natural mortality and somatic growth in a theoretical unexploited cohort, as well as a uniform bag limit for all user groups (5 fish per person per day)
- Full Text:
- Date Issued: 1988