The international community’s implementation of the Responsibility to Protect (R2P) Principle: a Comparative Study of Sudan and Libya
- Authors: Nizeimana, John Bosco
- Date: 2020
- Subjects: Responsibility to protect (International law) , Humanitarian intervention -- Libya , Libya -- Foreign relations -- 1969- , Libya -- Politics and government -- 1969- , Humanitarian intervention -- Sudan , Sudan -- Foreign relations , Sudan -- Politics and government -- 1985-
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162631 , vital:40962
- Description: In the history of international relations, the adoption of the R2P principle in 2005 was widely understood to be a break-through in the international community’s efforts to respond to massive human rights violations and atrocities. Despite this, the international community’s implementation of the R2P has been widely contested, including in relation to its application in Sudan and Libya. There is agreement in the literature that, in both cases, the implementation of the R2P failed to achieve its intended purpose of protecting civilian populations. This thesis addresses the question of why the R2P failed in Sudan and Libya. Most explanations concerning the failure of the R2P in Sudan and Libya tend to focus on the politics of big power countries. The study argues that the failure to implement the R2P is related to the interactions between regional organisations and the international community (global organisations like UN) in attempting to solve large-scale human rights violent conflict. The study is firmly embedded in scholarly debates about humanitarian intervention so as to demonstrate the fact that this study is part of efforts to advance knowledge of scholarly debates on humanitarian intervention in this contemporary world order. The study combines a case study approach and qualitative research approach to achieve a nuanced understanding of the reason why the R2P failed in Sudan and Libya. The study relied on the use of documentary reviews and in-depth interviews of experts to collect data which was analysed using critical discourse analysis. The thesis demonstrated that the implementation of the R2P was characterised by a breakdown of the relationship between regional actors like the AU and global institutions like the UN. This breakdown contributed to the failure of the R2P in Sudan and Libya. The lack of financial and operational capacity for rapid deployment, the internal divisions with the AU, and the lack of political will within the AU members states were also cited as obstacles to the realisation of the R2P efforts in Sudan. To establish in-depth knowledge the study revealed other factors related to the politics of big power countries and how they played a part in the failure of the R2P in Sudan and Libya. Among these factors include implementation inconsistencies, the ICC factor, the absence of UNSC consensus in the response over Darfur and Libya, and the veto power factor and its implications in the efforts of the international community in both cases. This study also showed that the implementation of the R2P may not work effectively if left only to international actors to implement. Regional and sub-regional actors are important stakeholders of the R2P, and their interactions with the international community in actualising the implmementation of the R2P on the ground are essential. The manner in which the R2P was applied in Sudan and Libya is an indication its implementation requires improved interaction between regional actors and the international community at all level of collaboration including at global, regional and sub-regional level. This can build a strong foundation to drive the effective implementation of the R2P in future interventions. The findings of this thesis will significantly improve the available literature on the reason why the R2P failed in Sudan and Libya, particularly by paying much attention to the role of regional and sub-regional actors.
- Full Text:
- Date Issued: 2020
- Authors: Nizeimana, John Bosco
- Date: 2020
- Subjects: Responsibility to protect (International law) , Humanitarian intervention -- Libya , Libya -- Foreign relations -- 1969- , Libya -- Politics and government -- 1969- , Humanitarian intervention -- Sudan , Sudan -- Foreign relations , Sudan -- Politics and government -- 1985-
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162631 , vital:40962
- Description: In the history of international relations, the adoption of the R2P principle in 2005 was widely understood to be a break-through in the international community’s efforts to respond to massive human rights violations and atrocities. Despite this, the international community’s implementation of the R2P has been widely contested, including in relation to its application in Sudan and Libya. There is agreement in the literature that, in both cases, the implementation of the R2P failed to achieve its intended purpose of protecting civilian populations. This thesis addresses the question of why the R2P failed in Sudan and Libya. Most explanations concerning the failure of the R2P in Sudan and Libya tend to focus on the politics of big power countries. The study argues that the failure to implement the R2P is related to the interactions between regional organisations and the international community (global organisations like UN) in attempting to solve large-scale human rights violent conflict. The study is firmly embedded in scholarly debates about humanitarian intervention so as to demonstrate the fact that this study is part of efforts to advance knowledge of scholarly debates on humanitarian intervention in this contemporary world order. The study combines a case study approach and qualitative research approach to achieve a nuanced understanding of the reason why the R2P failed in Sudan and Libya. The study relied on the use of documentary reviews and in-depth interviews of experts to collect data which was analysed using critical discourse analysis. The thesis demonstrated that the implementation of the R2P was characterised by a breakdown of the relationship between regional actors like the AU and global institutions like the UN. This breakdown contributed to the failure of the R2P in Sudan and Libya. The lack of financial and operational capacity for rapid deployment, the internal divisions with the AU, and the lack of political will within the AU members states were also cited as obstacles to the realisation of the R2P efforts in Sudan. To establish in-depth knowledge the study revealed other factors related to the politics of big power countries and how they played a part in the failure of the R2P in Sudan and Libya. Among these factors include implementation inconsistencies, the ICC factor, the absence of UNSC consensus in the response over Darfur and Libya, and the veto power factor and its implications in the efforts of the international community in both cases. This study also showed that the implementation of the R2P may not work effectively if left only to international actors to implement. Regional and sub-regional actors are important stakeholders of the R2P, and their interactions with the international community in actualising the implmementation of the R2P on the ground are essential. The manner in which the R2P was applied in Sudan and Libya is an indication its implementation requires improved interaction between regional actors and the international community at all level of collaboration including at global, regional and sub-regional level. This can build a strong foundation to drive the effective implementation of the R2P in future interventions. The findings of this thesis will significantly improve the available literature on the reason why the R2P failed in Sudan and Libya, particularly by paying much attention to the role of regional and sub-regional actors.
- Full Text:
- Date Issued: 2020
The lived experiences of women with human immunodeficiency virus (HIV) in Malawi: an interpretative phenomenological analysis (IPA)
- Authors: Nkhalamba, Mathero Michelle
- Date: 2020
- Subjects: HIV-positive women -- Malawi , HIV infections -- Sex factors -- Malawi , HIV infections -- Social aspects -- Malawi , HIV-positive women -- Malawi -- Social conditions , HIV-positive women -- Malawi -- Economic conditions , Poverty -- Malawi , Antiretroviral agents -- Malawi , Phenomenological psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145291 , vital:38425
- Description: Research on African women and HIV, particularly research that investigates their experiences of living with the virus, has been relatively peripheral. As a response to the apparent knowledge and research gaps, this project is a qualitative study involving women living with human immunodeficiency virus (WLHIV) and attending an anti-retroviral treatment (ART) clinic at Zomba Central Hospital in Southern Malawi. The study utilised an interpretative phenomenological analysis (IPA) approach, which informed all aspects of the data-collection and data-analysis processes. Using purposive sampling, 12 women were recruited and interviewed on three occasions over a period of six months. The interviews were conducted in Chichewa and audio recorded and later transcribed into English. Fourteen superordinate themes emerged from the analysis representing the women’s prominent life experiences, how they received their diagnosis, and how they contained the trauma of their diagnosis. The analysis also developed themes regarding how they coped with the challenges of living with the human immunodeficiency virus (HIV) and made sense of their experiences. The results showed that the women struggled with multiple challenges experienced through their various identities as WLHIV. The findings also pointed to interlocking disadvantages that put the women at risk of infection, and which were present from childhood. This has implications for more structural and multidisciplinary interventions for WLHIV.
- Full Text:
- Date Issued: 2020
- Authors: Nkhalamba, Mathero Michelle
- Date: 2020
- Subjects: HIV-positive women -- Malawi , HIV infections -- Sex factors -- Malawi , HIV infections -- Social aspects -- Malawi , HIV-positive women -- Malawi -- Social conditions , HIV-positive women -- Malawi -- Economic conditions , Poverty -- Malawi , Antiretroviral agents -- Malawi , Phenomenological psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145291 , vital:38425
- Description: Research on African women and HIV, particularly research that investigates their experiences of living with the virus, has been relatively peripheral. As a response to the apparent knowledge and research gaps, this project is a qualitative study involving women living with human immunodeficiency virus (WLHIV) and attending an anti-retroviral treatment (ART) clinic at Zomba Central Hospital in Southern Malawi. The study utilised an interpretative phenomenological analysis (IPA) approach, which informed all aspects of the data-collection and data-analysis processes. Using purposive sampling, 12 women were recruited and interviewed on three occasions over a period of six months. The interviews were conducted in Chichewa and audio recorded and later transcribed into English. Fourteen superordinate themes emerged from the analysis representing the women’s prominent life experiences, how they received their diagnosis, and how they contained the trauma of their diagnosis. The analysis also developed themes regarding how they coped with the challenges of living with the human immunodeficiency virus (HIV) and made sense of their experiences. The results showed that the women struggled with multiple challenges experienced through their various identities as WLHIV. The findings also pointed to interlocking disadvantages that put the women at risk of infection, and which were present from childhood. This has implications for more structural and multidisciplinary interventions for WLHIV.
- Full Text:
- Date Issued: 2020
The management of lions (Panthera Leo) in small, fenced wildlife reserves
- Authors: McEvoy, Orla
- Date: 2020
- Subjects: Lion -- Behavior -- South Africa , Spatial behavior in animals -- South Africa , Animal populations -- South Africa , Game reserves -- South Africa -- Management
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143471 , vital:38249
- Description: Reintroduced lion (Panthera leo) populations pose several ecological and management challenges in small (< 1,000 km2), fenced wildlife reserves. Changes in the natural socialecological conditions of reintroduced lion populations may lead to rapid population growth and a breakdown of natural predator-prey relationships. Reduced competition with other lions also likely reduces the potential for reintroduced lions to naturally form groups. My study used a combination of questionnaire surveys with tourists, existing lion demographic data from 16 wildlife reserves across South Africa and a controlled lion social experiment to address these ecological and management issues. Tourism was the primary reason for lion reintroductions. Tourists scored lions highly in terms of preference for viewing on safari, in particular, lions in larger, natural groups and adult males. Viewing lions also enhanced a tourists’ overall safari experience. The breakdown of natural social behaviour may likely therefore reduce tourist satisfaction related to lions. The number of resident prides and male coalitions in a reserve affected lion vital rates. Lion population growth rate was highest in reserves that contained a single resident pride, and the presence of unknown adult males significantly reduced cub survival and lioness birth intervals. The ratio of male cubs born also increased in reserves with a higher density of unknown adult males. Fertility control measures (deslorelin implants and unilateral hysterectomy) were effective at limiting lion population growth. Deslorelin treatment increased the age of first reproduction or the birth interval and decreased the subsequent litter size of treated lionesses to closer reflect natural vital rates in larger (> 10, 000 km2) systems. However, there was variability in infertility response between lionesses including adverse reactions in a small proportion of treated individuals. The number of resident prides and male coalitions in a reserve affected lion social behaviour. Lionesses formed larger groups in reserves with a higher density of unknown adult female neighbours, likely driven by territory defence. Lion prides with resident cubs were generally more fragmented, likely in response to reduced competition from unknown adult males. However, in areas with a high density of unknown adult female neighbours, prides with cubs formed larger groups likely in response to heightened territory defence. Therefore, with smaller foraging group sizes, predation rate was increased in reserves with reduced competition from unknown lions. My study supports a metapopulation approach for the management of lions in small, fenced reserves, and the standardisation of lion management procedures and database management. Endorsed by the Biodiversity Management Plan for lions in South Africa, this will enhance the long-term conservation potential of isolated populations.
- Full Text:
- Date Issued: 2020
- Authors: McEvoy, Orla
- Date: 2020
- Subjects: Lion -- Behavior -- South Africa , Spatial behavior in animals -- South Africa , Animal populations -- South Africa , Game reserves -- South Africa -- Management
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143471 , vital:38249
- Description: Reintroduced lion (Panthera leo) populations pose several ecological and management challenges in small (< 1,000 km2), fenced wildlife reserves. Changes in the natural socialecological conditions of reintroduced lion populations may lead to rapid population growth and a breakdown of natural predator-prey relationships. Reduced competition with other lions also likely reduces the potential for reintroduced lions to naturally form groups. My study used a combination of questionnaire surveys with tourists, existing lion demographic data from 16 wildlife reserves across South Africa and a controlled lion social experiment to address these ecological and management issues. Tourism was the primary reason for lion reintroductions. Tourists scored lions highly in terms of preference for viewing on safari, in particular, lions in larger, natural groups and adult males. Viewing lions also enhanced a tourists’ overall safari experience. The breakdown of natural social behaviour may likely therefore reduce tourist satisfaction related to lions. The number of resident prides and male coalitions in a reserve affected lion vital rates. Lion population growth rate was highest in reserves that contained a single resident pride, and the presence of unknown adult males significantly reduced cub survival and lioness birth intervals. The ratio of male cubs born also increased in reserves with a higher density of unknown adult males. Fertility control measures (deslorelin implants and unilateral hysterectomy) were effective at limiting lion population growth. Deslorelin treatment increased the age of first reproduction or the birth interval and decreased the subsequent litter size of treated lionesses to closer reflect natural vital rates in larger (> 10, 000 km2) systems. However, there was variability in infertility response between lionesses including adverse reactions in a small proportion of treated individuals. The number of resident prides and male coalitions in a reserve affected lion social behaviour. Lionesses formed larger groups in reserves with a higher density of unknown adult female neighbours, likely driven by territory defence. Lion prides with resident cubs were generally more fragmented, likely in response to reduced competition from unknown adult males. However, in areas with a high density of unknown adult female neighbours, prides with cubs formed larger groups likely in response to heightened territory defence. Therefore, with smaller foraging group sizes, predation rate was increased in reserves with reduced competition from unknown lions. My study supports a metapopulation approach for the management of lions in small, fenced reserves, and the standardisation of lion management procedures and database management. Endorsed by the Biodiversity Management Plan for lions in South Africa, this will enhance the long-term conservation potential of isolated populations.
- Full Text:
- Date Issued: 2020
The political promise of choreography in performance and/as research: First Physical Theatre Company’s manifesto and repertory, 1993-2015
- Authors: Finestone-Praeg, Juanita
- Date: 2020
- Subjects: Choreography -- Political aspects , Dance -- South Africa -- Makhanda , Dance -- Political aspects , Performance art -- South Africa -- Makhanda , Performance art -- History and criticism , Performance art -- Research , Performance art -- Study and teaching , Performance art -- Philosophy , Experimental theater -- South Africa -- Makhanda , Experimental theater -- History and criticism , Political art -- South Africa -- Makhanda , First Physical Theatre Company , First Physical Theatre Company -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/149373 , vital:38844
- Description: This study redefines the political in dance by drawing on the scholarly concept of the “choreopolitical” (André Lepecki) and extending it into analysing related concepts such as the “postdramatic” (Hans-Thies Lehmann), performance and/as research, among others from Performance Studies scholarship as well as from First Physical Theatre Company’s pioneering legacy of production, pedagogy and research in making Phyical Theatre performance. Following from the notion that performance is both a site and a method of study/knowing, the research invites a rethinking of the relationship between art (performance), epistemology and the political, in the sense that performance becomes a way, not of simply re-presenting the political but, as its own way of knowing, actively questioning the very categories on which the political is premised. The argument for Physical Theatre as having nascent potential to invoke what I call “the power of the small” is analysed as a choreopolitical method and community of practice that has a generative capacity to produce the “intimate revolts” (Julia Kristeva) or body of questions that can perform the imaginative curiosities/forms required to create provocative, subversive, ethical, reflexive and charged performance. My argument is supported by critical commentary, insight, choreological analysis and reflection on the dramaturgical strategies and choreopolitics of selected commissioned choreographers and dance forms that extended FPTC’s manifesto and production between 1993 and 2015. My project has the following three goals: (i) to contextualise, conceptualise and identify key issues in the identity, pedagogy and performance ethos of Physical Theatre as a performance philosophy and form; (ii) to engage critically with the praxis of Physical Theatre within the contextual, cultural, historical and political relationships between Physical Theatre and other performance practices in South Africa; and (iii) to document, analyse and interpret selected claims, works and performance processes from the archive of FPTC’s repertory and training manifesto from 1993 to 2015. The research evaluates the political significance and consequence of FPTC’s heritage and legacy problematising constraints, possibilities, tensions, failures and proposing the hope of imaginative entanglements with practising freedoms.
- Full Text:
- Date Issued: 2020
- Authors: Finestone-Praeg, Juanita
- Date: 2020
- Subjects: Choreography -- Political aspects , Dance -- South Africa -- Makhanda , Dance -- Political aspects , Performance art -- South Africa -- Makhanda , Performance art -- History and criticism , Performance art -- Research , Performance art -- Study and teaching , Performance art -- Philosophy , Experimental theater -- South Africa -- Makhanda , Experimental theater -- History and criticism , Political art -- South Africa -- Makhanda , First Physical Theatre Company , First Physical Theatre Company -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/149373 , vital:38844
- Description: This study redefines the political in dance by drawing on the scholarly concept of the “choreopolitical” (André Lepecki) and extending it into analysing related concepts such as the “postdramatic” (Hans-Thies Lehmann), performance and/as research, among others from Performance Studies scholarship as well as from First Physical Theatre Company’s pioneering legacy of production, pedagogy and research in making Phyical Theatre performance. Following from the notion that performance is both a site and a method of study/knowing, the research invites a rethinking of the relationship between art (performance), epistemology and the political, in the sense that performance becomes a way, not of simply re-presenting the political but, as its own way of knowing, actively questioning the very categories on which the political is premised. The argument for Physical Theatre as having nascent potential to invoke what I call “the power of the small” is analysed as a choreopolitical method and community of practice that has a generative capacity to produce the “intimate revolts” (Julia Kristeva) or body of questions that can perform the imaginative curiosities/forms required to create provocative, subversive, ethical, reflexive and charged performance. My argument is supported by critical commentary, insight, choreological analysis and reflection on the dramaturgical strategies and choreopolitics of selected commissioned choreographers and dance forms that extended FPTC’s manifesto and production between 1993 and 2015. My project has the following three goals: (i) to contextualise, conceptualise and identify key issues in the identity, pedagogy and performance ethos of Physical Theatre as a performance philosophy and form; (ii) to engage critically with the praxis of Physical Theatre within the contextual, cultural, historical and political relationships between Physical Theatre and other performance practices in South Africa; and (iii) to document, analyse and interpret selected claims, works and performance processes from the archive of FPTC’s repertory and training manifesto from 1993 to 2015. The research evaluates the political significance and consequence of FPTC’s heritage and legacy problematising constraints, possibilities, tensions, failures and proposing the hope of imaginative entanglements with practising freedoms.
- Full Text:
- Date Issued: 2020
The precarious ‘good mother’ position: a psychosocial reading of maternal subjectivity of working mothers in scarcely-resourced South African communities
- Authors: Kinahan-Sweeney, Siobhan
- Date: 2020
- Subjects: Motherhood -- Psychological aspects -- South Africa , Working mothers -- South Africa -- Attitudes , Working mothers -- South Africa -- Psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142464 , vital:38082
- Description: This psychosocial study investigates the maternal subjectivities of mothers returning to work after maternity leave, who are living in scarcely-resourced Cape Town communities in South Africa. Engaging with interview texts and listening to mothers’ talk, I explore how and why maternal subjectivity is constructed discursively and defensively in our talk. This thesis claims that these particular mothers predominately employ instrumental mothering discourse. The traditional subject position of the intensive mother – which is typically assumed to be the ‘good mother’ – is not a position available to these mothers due to their social circumstances and working role. Subsequently, material provision, the baby’s thriving and surviving body, finding substitute carers and maternal preoccupation are constructed as qualities of ‘good mothering’ in their talk. This ‘good mother’ position, however, is a precarious position that both these mothers and I invest in to defend against feelings towards their babies and themselves as well as to deny (maternal) ambivalence in a problematic social system. In a combined analysis drawing on discursive theory and psychoanalysis, more specifically contemporary attachment theory and intersubjectivity theory, I illustrate how both these mothers and I – as emotional, social and political subjects – co-construct maternal subjectivity. Based on the findings, recommendations for parent-infant interventions are discussed. Arguing that a purely psychoanalytic reading of investment perpetuates notions of individual blame and pathology, I advocate for a psychosocial reading that does not neglect failing social systems but rather pursues an open and reflective, yet critical, mindfulness when listening to talk.
- Full Text:
- Date Issued: 2020
- Authors: Kinahan-Sweeney, Siobhan
- Date: 2020
- Subjects: Motherhood -- Psychological aspects -- South Africa , Working mothers -- South Africa -- Attitudes , Working mothers -- South Africa -- Psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142464 , vital:38082
- Description: This psychosocial study investigates the maternal subjectivities of mothers returning to work after maternity leave, who are living in scarcely-resourced Cape Town communities in South Africa. Engaging with interview texts and listening to mothers’ talk, I explore how and why maternal subjectivity is constructed discursively and defensively in our talk. This thesis claims that these particular mothers predominately employ instrumental mothering discourse. The traditional subject position of the intensive mother – which is typically assumed to be the ‘good mother’ – is not a position available to these mothers due to their social circumstances and working role. Subsequently, material provision, the baby’s thriving and surviving body, finding substitute carers and maternal preoccupation are constructed as qualities of ‘good mothering’ in their talk. This ‘good mother’ position, however, is a precarious position that both these mothers and I invest in to defend against feelings towards their babies and themselves as well as to deny (maternal) ambivalence in a problematic social system. In a combined analysis drawing on discursive theory and psychoanalysis, more specifically contemporary attachment theory and intersubjectivity theory, I illustrate how both these mothers and I – as emotional, social and political subjects – co-construct maternal subjectivity. Based on the findings, recommendations for parent-infant interventions are discussed. Arguing that a purely psychoanalytic reading of investment perpetuates notions of individual blame and pathology, I advocate for a psychosocial reading that does not neglect failing social systems but rather pursues an open and reflective, yet critical, mindfulness when listening to talk.
- Full Text:
- Date Issued: 2020
The role of microhabitats within mangroves: an invertebrate and fish larval perspective
- Authors: Vorsatz, Lyle Dennis
- Date: 2020
- Subjects: Mangrove ecology -- South Africa , Mangrove forests -- South Africa , Niche (Ecology) , Rhizophora mucronata , Acanthaceae , Rhizophoraceae , Fishes -- Larvae -- South Africa , Aquatic ecology -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167644 , vital:41499
- Description: Microhabitats provided through structural complexity are central for the diversity, productivity, connectivity and niche differentiation within and among ecosystems. Mangrove forests afford juvenile fish and invertebrates with nursery and recruitment habitats, facilitated by the fine scale configuration of their specialised root systems. Although the importance of mangroves for resident and transient juveniles is well recognised, the roles that mangrove microhabitats play for larvae is not yet comprehensively understood. This study aimed to determine how microhabitats with varying degrees of complexity influence the composition, abundance and distribution of larval communities that inhabit mangrove forests and the physiological responses of larvae to acute temperature variations in relation to ontogenetic stage and microenvironment exposure. Two relatively pristine study sites were selected to represent a warm temperate and subtropical mangrove system in the Eastern Cape and KwaZulu-Natal on the east coast of South Africa, respectively. The differences in complexity among the root systems of Rhizophora mucronata, Avicennia marina and Bruguiera gymnorhiza were assessed using 3D scanning and the computed 3D models were then analysed using four complexity metrics. Results indicated that A. marina is the most complex in terms of surface-volume ratio, R. mucronata has the most interstitial space among its roots and B. gymnorhiza and R. mucronata differ in their fractal dimensions. Larvae collected in each microhabitat at each site using light traps showed that, despite temperature and salinity homogeneity across microenvironments, spatio-temporal differences occurred in both fish and invertebrate assemblages. This trend suggests that microhabitat structural complexity exerts an influence on larval community composition by acting as a microscape of available habitat, which ensures ecological linkages within and among the mangrove forest and adjacent ecosystems. In addition, the oxygen consumption rates of mangrove-associated brachyuran larvae varied according to mangrove microhabitat, whereby larvae collected at less complex environments had the highest metabolic rates at increased temperatures. Moreover, ontogenetic shifts in physiology were prevalent as older brachyuran larvae were more eurythermal than earlier stages, suggesting that thermally stressful events will have a greater impact on recently spawned larvae. Overall, the interstitial spaces within individual root systems are the most important complexity measure, as utilisation of these mangrove microhabitats is scale-dependent, and larvae will most likely occupy spaces inaccessible to large predators. Likewise, microscale variation in the environmental conditions and ontogenetic stage of brachyuran larvae within the mangrove microscape, can amplify the physiological responses to rapid temperature variations. Results suggest that early stage larvae are the most vulnerable to mass-mortality, and if thermally stressful events increase in frequency, duration and magnitude, the larval supply for the successful recruitment into adult populations could be under threat. Through linking how mangrove microhabitat complexity influences larvae in terms of community metrics and physiology, this study paves the way for further advancement of our understanding of how microscale processes emerge into meso- and macroscale patterns and influence the stability and functioning of highly productive ecosystems.
- Full Text:
- Date Issued: 2020
- Authors: Vorsatz, Lyle Dennis
- Date: 2020
- Subjects: Mangrove ecology -- South Africa , Mangrove forests -- South Africa , Niche (Ecology) , Rhizophora mucronata , Acanthaceae , Rhizophoraceae , Fishes -- Larvae -- South Africa , Aquatic ecology -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167644 , vital:41499
- Description: Microhabitats provided through structural complexity are central for the diversity, productivity, connectivity and niche differentiation within and among ecosystems. Mangrove forests afford juvenile fish and invertebrates with nursery and recruitment habitats, facilitated by the fine scale configuration of their specialised root systems. Although the importance of mangroves for resident and transient juveniles is well recognised, the roles that mangrove microhabitats play for larvae is not yet comprehensively understood. This study aimed to determine how microhabitats with varying degrees of complexity influence the composition, abundance and distribution of larval communities that inhabit mangrove forests and the physiological responses of larvae to acute temperature variations in relation to ontogenetic stage and microenvironment exposure. Two relatively pristine study sites were selected to represent a warm temperate and subtropical mangrove system in the Eastern Cape and KwaZulu-Natal on the east coast of South Africa, respectively. The differences in complexity among the root systems of Rhizophora mucronata, Avicennia marina and Bruguiera gymnorhiza were assessed using 3D scanning and the computed 3D models were then analysed using four complexity metrics. Results indicated that A. marina is the most complex in terms of surface-volume ratio, R. mucronata has the most interstitial space among its roots and B. gymnorhiza and R. mucronata differ in their fractal dimensions. Larvae collected in each microhabitat at each site using light traps showed that, despite temperature and salinity homogeneity across microenvironments, spatio-temporal differences occurred in both fish and invertebrate assemblages. This trend suggests that microhabitat structural complexity exerts an influence on larval community composition by acting as a microscape of available habitat, which ensures ecological linkages within and among the mangrove forest and adjacent ecosystems. In addition, the oxygen consumption rates of mangrove-associated brachyuran larvae varied according to mangrove microhabitat, whereby larvae collected at less complex environments had the highest metabolic rates at increased temperatures. Moreover, ontogenetic shifts in physiology were prevalent as older brachyuran larvae were more eurythermal than earlier stages, suggesting that thermally stressful events will have a greater impact on recently spawned larvae. Overall, the interstitial spaces within individual root systems are the most important complexity measure, as utilisation of these mangrove microhabitats is scale-dependent, and larvae will most likely occupy spaces inaccessible to large predators. Likewise, microscale variation in the environmental conditions and ontogenetic stage of brachyuran larvae within the mangrove microscape, can amplify the physiological responses to rapid temperature variations. Results suggest that early stage larvae are the most vulnerable to mass-mortality, and if thermally stressful events increase in frequency, duration and magnitude, the larval supply for the successful recruitment into adult populations could be under threat. Through linking how mangrove microhabitat complexity influences larvae in terms of community metrics and physiology, this study paves the way for further advancement of our understanding of how microscale processes emerge into meso- and macroscale patterns and influence the stability and functioning of highly productive ecosystems.
- Full Text:
- Date Issued: 2020
The role of the Hop co-chaperone in the formation of Hsp90 complexes: chaperone link to glycolysis
- Authors: Maharaj, Shantal
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163593 , vital:41051 , doi:10.21504/10962/163593
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Maharaj, Shantal
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163593 , vital:41051 , doi:10.21504/10962/163593
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
The taxonomic status of dolphins Tursiops spp. and Delphinus in South African waters
- Authors: Ngqulana, Sibusisiwe Gloria
- Date: 2020
- Subjects: Dolphins -- Classification -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48566 , vital:40891
- Description: There is a need for identifying important sites, taxonomic units or populations and the usual criterion used is species identification. The species is the most important taxonomic unit to define in taxonomy, as it is the primary unit of concern in biodiversity, conservation and other biological issues. Thus, taxonomy plays an important role in conservation biology. Additionally, taxonomy can contribute to the development of analytical systems that will provide information on priorities for reaching defensible targets for established conservation. This poses a problem for cetaceans as basic information is frequently deficient and therefore not suitable for conservation planning purposes. This leads to difficulties in identifying and prioritizing areas for the monitoring, management and for the protection of species or populations. Morphological and geographic data used to be the primary means used by taxonomists to define species and subspecies, and due to this, most extant species have been classified by morphological characteristics. However, in the recent years, molecular analyses have been introduced and subsequently stable isotopes were also included to assist in interpreting results. Thereafter, it became a common approach to use more than one technique or a combination of independent datasets to resolve taxonomic uncertainties. This has resulted to a proposed term known as integrative taxonomy. Integrative taxonomy has recently been used in most studies that deal with taxonomy or population structure. The use of multiple lines of evidence, which is sometimes referred to as integrative taxonomy, raises the level of confidence in clearly delineating species. Cetaceans are the most taxonomically diverse group of aquatic mammals, with 93 living species accepted. Previously, their taxonomy was based on morphological characters. However, cetaceans have recently been subjected to intense phylogenetic investigations using both morphological and molecular data. These problems are not only prevalent in larger whales, but the small toothed whales also have these challenges, particularly family Delphinidae. This family is known to be the most diverse among the toothed whales. This is because this family diverged recently, and the divergence occurred relatively fast. This study aimed to clarify the taxonomic status of Tursiops spp. and Delphinus in the family Delphinidae, inhabiting the South African waters, using a combination of morphological and molecular methods. For skull morphology, geometric morphometrics were used, while for molecular methods, the D-loop region in the mitochondrial DNA was used to detect any differences within each genus. For the genus Tursiops, this study showed the consistency of results in all analyses used to investigate the presence of two species in the genus Tursiops in South African waters. This study only analysed sequences from the mitochondrial D-loop region and has re-confirmed the presence of the two species in South Africa. Skull and external morphology both show T. truncatus to be bigger and more robust, and to have a shorter rostrum compared with T. aduncus. These external observations are helpful when identifying the species in the field. Providing evidence supporting the presence of two Tursiops species in South Africa does not only contribute to the global context of the taxonomy of this genus, but also in the local context. This study also gives insight on the distribution of the two species in the region. For the genus Delphinus, molecular analysis did not reveal any clustering in South African Delphinus specimens, which suggested a single species, D. delphis, and that this species is morphologically highly variable. Both skull and external morphology did not reflect the molecular results, supporting suggestions that morphology in this genus does not reflect genetic differences. It has been shown that morphological variation reflects feeding specialization rather than speciation. This may also reflect local adaptations. Both skull and external morphology in this study showed no significant differences. This study did not investigate the phylogeographic details of the species in South Africa and further molecular work including a larger sample size from the west coast of South Africa is needed. By attempting to unravel the taxonomy of these dolphins in South African waters, the findings of this study will be very useful in the development of effective conservation and management strategies for these dolphins.
- Full Text:
- Date Issued: 2020
- Authors: Ngqulana, Sibusisiwe Gloria
- Date: 2020
- Subjects: Dolphins -- Classification -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48566 , vital:40891
- Description: There is a need for identifying important sites, taxonomic units or populations and the usual criterion used is species identification. The species is the most important taxonomic unit to define in taxonomy, as it is the primary unit of concern in biodiversity, conservation and other biological issues. Thus, taxonomy plays an important role in conservation biology. Additionally, taxonomy can contribute to the development of analytical systems that will provide information on priorities for reaching defensible targets for established conservation. This poses a problem for cetaceans as basic information is frequently deficient and therefore not suitable for conservation planning purposes. This leads to difficulties in identifying and prioritizing areas for the monitoring, management and for the protection of species or populations. Morphological and geographic data used to be the primary means used by taxonomists to define species and subspecies, and due to this, most extant species have been classified by morphological characteristics. However, in the recent years, molecular analyses have been introduced and subsequently stable isotopes were also included to assist in interpreting results. Thereafter, it became a common approach to use more than one technique or a combination of independent datasets to resolve taxonomic uncertainties. This has resulted to a proposed term known as integrative taxonomy. Integrative taxonomy has recently been used in most studies that deal with taxonomy or population structure. The use of multiple lines of evidence, which is sometimes referred to as integrative taxonomy, raises the level of confidence in clearly delineating species. Cetaceans are the most taxonomically diverse group of aquatic mammals, with 93 living species accepted. Previously, their taxonomy was based on morphological characters. However, cetaceans have recently been subjected to intense phylogenetic investigations using both morphological and molecular data. These problems are not only prevalent in larger whales, but the small toothed whales also have these challenges, particularly family Delphinidae. This family is known to be the most diverse among the toothed whales. This is because this family diverged recently, and the divergence occurred relatively fast. This study aimed to clarify the taxonomic status of Tursiops spp. and Delphinus in the family Delphinidae, inhabiting the South African waters, using a combination of morphological and molecular methods. For skull morphology, geometric morphometrics were used, while for molecular methods, the D-loop region in the mitochondrial DNA was used to detect any differences within each genus. For the genus Tursiops, this study showed the consistency of results in all analyses used to investigate the presence of two species in the genus Tursiops in South African waters. This study only analysed sequences from the mitochondrial D-loop region and has re-confirmed the presence of the two species in South Africa. Skull and external morphology both show T. truncatus to be bigger and more robust, and to have a shorter rostrum compared with T. aduncus. These external observations are helpful when identifying the species in the field. Providing evidence supporting the presence of two Tursiops species in South Africa does not only contribute to the global context of the taxonomy of this genus, but also in the local context. This study also gives insight on the distribution of the two species in the region. For the genus Delphinus, molecular analysis did not reveal any clustering in South African Delphinus specimens, which suggested a single species, D. delphis, and that this species is morphologically highly variable. Both skull and external morphology did not reflect the molecular results, supporting suggestions that morphology in this genus does not reflect genetic differences. It has been shown that morphological variation reflects feeding specialization rather than speciation. This may also reflect local adaptations. Both skull and external morphology in this study showed no significant differences. This study did not investigate the phylogeographic details of the species in South Africa and further molecular work including a larger sample size from the west coast of South Africa is needed. By attempting to unravel the taxonomy of these dolphins in South African waters, the findings of this study will be very useful in the development of effective conservation and management strategies for these dolphins.
- Full Text:
- Date Issued: 2020
Thermal tolerance and the potential effects of climate change on coastal intertidal and estuarine organisms in the Kariega Estuary and adjacent intertitdal coastline, Eastern Cape, South Africa
- Authors: Van der Walt, Kerry-Ann
- Date: 2020
- Subjects: Ectotherms -- Climatic factors , Ectotherms -- Effect of temperature on , Fishes -- Climatic factors , Fishes -- Effect of temperature on , Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/148459 , vital:38741
- Description: Temperature changes due to the effects of climate change are evident on all continents and oceans. As a result, there is a growing concern over how marine ectotherms will respond to extreme or fluctuating environmental temperatures. Temperature changes have strong direct and indirect effects on individual, population, and ecosystem functioning traits. A multi-scale approach determining the thermal tolerance and performance of several marine ectotherms belonging to different coastal habitats is rarely considered in thermal physiology studies but is effective for an integrated ecosystem assessment. As such, for this thesis, I aimed to quantify and compare the thermal tolerance and performance of a range of coastal marine ectotherms (fish and macro-invertebrates) with different biogeographical distributions from estuarine, subtidal and rocky intertidal habitats to available and projected in situ temperature data. This was also undertaken to gauge the local vulnerability of each species across summer and winter in a warm-temperate region of South Africa. This was done using a multi-method physiological approach, which included the dynamic method (CTmax and CTmin), static respirometry and maximum heart rate fHmax). Results of the dynamic method on several fish and macro-invertebrate species indicated that there are differences in thermal tolerance according to taxonomy, biogeography and habitat for both summer and winter. Macro-invertebrate species generally had higher CTmax endpoints, lower CTmin endpoints, higher upper and lower breadths in tolerance, higher upper and lower thermal safety margins and higher thermal scopes than the fish species. This could be a result of the macro-invertebrate species studied being less mobile compared with fish species (which are able to move to more favourable conditions) as well as having broader geographical distributions. In addition, macro-invertebrates from the intertidal rock pool habitat (Palaemon peringueyi; Pernaperna) were more tolerant of high and low temperatures compared with the macro-invertebrates from the estuarine habitat (Clibanarius virescens; Parasesarma catenatum; Upogebia africana). Overall, macro-invertebrates, with the exception of Parechinus angulosus, investigated in this study indicated that current temperatures and projected climate change scenarios across seasons would not have a significant impact on them and that they are highly adaptable to changing temperature regimes. This sign of high tolerance was further supported by the heart rates of P. perna and P. catenatum under an acute increase in temperature (1.0 °C.h-1) which showed individuals of each species physiologically depressing their metabolism until a final Arrhenius breakpoint temperature was reached (TAB). Among the fish species investigated in this study, tropical species (Chaetodon marleyi; Kuhlia mugil) had the highest CTmax and CTmin endpoints when compared with the temperate (Diplodus capensis; Sarpa salpa), warm-water endemic (Chelon dumerili; Rhabdosargus holubi) and cool-water endemic (Chelon richardsonii) fishes. This suggests that due to their lower breadths in tolerance and thermal safety margins being small, tropical species may be less tolerant of cold temperatures and thermal variability, especially in the form of summer upwelling events which are expected to increase in intensity and frequency in this region as a result of anthropogenic climate change effects. On the other hand, however, if a temperature increase of 2.0 - 4.0 °C takes place at the end of the century as predicted by the Intergovernmental Panel on Climate Change (IPCC), it is likely that tropical species such as C. marleyi will become more common. Temperate species such as D. capensis and S. salpa were able to tolerate a wide range of temperatures (wide thermal scope) compared with the other fish species. These findings may suggest that D. capensis and S. salpa are thermally resilient and may be the least vulnerable to climate change effects and temperature variability. When evaluating the different life stages of D. capensis, however, using the dynamic method (juveniles and adults), static respirometry (juveniles) and maximum heart rate (adults), results suggested that juveniles of this temperate species will be more resilient to increases in ocean temperatures compared with the adults because they have a higher thermal tolerance (CTmax/TCRIT) and a greater metabolic scope (TOPT) at higher temperatures. For both juveniles and adults, temperatures beyond 28.0 °C (upper Tpej; Tarr) will have a significant impact on their physiology. Using a multi-scale and multi-method approach thus helped to identify which species or community may be vulnerable to the effects of climate change within shallow coastal environments in this warm-temperate climate change hotspot. Adopting this type of approach will assist policy makers in developing comprehensive climate change management frameworks for coastal ecosystems globally and around South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Van der Walt, Kerry-Ann
- Date: 2020
- Subjects: Ectotherms -- Climatic factors , Ectotherms -- Effect of temperature on , Fishes -- Climatic factors , Fishes -- Effect of temperature on , Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/148459 , vital:38741
- Description: Temperature changes due to the effects of climate change are evident on all continents and oceans. As a result, there is a growing concern over how marine ectotherms will respond to extreme or fluctuating environmental temperatures. Temperature changes have strong direct and indirect effects on individual, population, and ecosystem functioning traits. A multi-scale approach determining the thermal tolerance and performance of several marine ectotherms belonging to different coastal habitats is rarely considered in thermal physiology studies but is effective for an integrated ecosystem assessment. As such, for this thesis, I aimed to quantify and compare the thermal tolerance and performance of a range of coastal marine ectotherms (fish and macro-invertebrates) with different biogeographical distributions from estuarine, subtidal and rocky intertidal habitats to available and projected in situ temperature data. This was also undertaken to gauge the local vulnerability of each species across summer and winter in a warm-temperate region of South Africa. This was done using a multi-method physiological approach, which included the dynamic method (CTmax and CTmin), static respirometry and maximum heart rate fHmax). Results of the dynamic method on several fish and macro-invertebrate species indicated that there are differences in thermal tolerance according to taxonomy, biogeography and habitat for both summer and winter. Macro-invertebrate species generally had higher CTmax endpoints, lower CTmin endpoints, higher upper and lower breadths in tolerance, higher upper and lower thermal safety margins and higher thermal scopes than the fish species. This could be a result of the macro-invertebrate species studied being less mobile compared with fish species (which are able to move to more favourable conditions) as well as having broader geographical distributions. In addition, macro-invertebrates from the intertidal rock pool habitat (Palaemon peringueyi; Pernaperna) were more tolerant of high and low temperatures compared with the macro-invertebrates from the estuarine habitat (Clibanarius virescens; Parasesarma catenatum; Upogebia africana). Overall, macro-invertebrates, with the exception of Parechinus angulosus, investigated in this study indicated that current temperatures and projected climate change scenarios across seasons would not have a significant impact on them and that they are highly adaptable to changing temperature regimes. This sign of high tolerance was further supported by the heart rates of P. perna and P. catenatum under an acute increase in temperature (1.0 °C.h-1) which showed individuals of each species physiologically depressing their metabolism until a final Arrhenius breakpoint temperature was reached (TAB). Among the fish species investigated in this study, tropical species (Chaetodon marleyi; Kuhlia mugil) had the highest CTmax and CTmin endpoints when compared with the temperate (Diplodus capensis; Sarpa salpa), warm-water endemic (Chelon dumerili; Rhabdosargus holubi) and cool-water endemic (Chelon richardsonii) fishes. This suggests that due to their lower breadths in tolerance and thermal safety margins being small, tropical species may be less tolerant of cold temperatures and thermal variability, especially in the form of summer upwelling events which are expected to increase in intensity and frequency in this region as a result of anthropogenic climate change effects. On the other hand, however, if a temperature increase of 2.0 - 4.0 °C takes place at the end of the century as predicted by the Intergovernmental Panel on Climate Change (IPCC), it is likely that tropical species such as C. marleyi will become more common. Temperate species such as D. capensis and S. salpa were able to tolerate a wide range of temperatures (wide thermal scope) compared with the other fish species. These findings may suggest that D. capensis and S. salpa are thermally resilient and may be the least vulnerable to climate change effects and temperature variability. When evaluating the different life stages of D. capensis, however, using the dynamic method (juveniles and adults), static respirometry (juveniles) and maximum heart rate (adults), results suggested that juveniles of this temperate species will be more resilient to increases in ocean temperatures compared with the adults because they have a higher thermal tolerance (CTmax/TCRIT) and a greater metabolic scope (TOPT) at higher temperatures. For both juveniles and adults, temperatures beyond 28.0 °C (upper Tpej; Tarr) will have a significant impact on their physiology. Using a multi-scale and multi-method approach thus helped to identify which species or community may be vulnerable to the effects of climate change within shallow coastal environments in this warm-temperate climate change hotspot. Adopting this type of approach will assist policy makers in developing comprehensive climate change management frameworks for coastal ecosystems globally and around South Africa.
- Full Text:
- Date Issued: 2020
Thermoluminescence and phototransferred phermoluminescence of synthetic quartz
- Authors: Dawam, Robert Rangmou
- Date: 2020
- Subjects: Thermoluminescence , Quartz
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145849 , vital:38472
- Description: The main aim of this investigation is on thermoluminescence and phototransferred thermoluminescence of synthetic quartz. Thermoluminescence was one of the tools used in characterising the electron traps parameters. The samples of quartz annealed at various temperatures up to 900̊C and the unannealed were used. The thermoluminescence glow curve was measured at 1̊C s~ 1 following beta irradiation to 40 Gy from the samples annealed at 500̊C and the unannealed consist of main peak at 70̊C and secondary peaks at 110, 180 and 310̊C. In comparison, the thermoluminescence glow curve for the sample annealed at 900̊C have main peak at 86̊C and the secondary ones at 170 and 310̊C. The kinetic analysis was carried out only on the main peak in each case. The activation energy was found to be decreasing with increase in annealing temperatures. The samples annealed at 500̊C and the unannealed were found to be affected by thermal quenching while sample annealed at 900̊C shows an inverse quenching for irradiation dose of 40 Gy. However, when the dose was reduce to 3 Gy the effects of thermal quenching was manifested. The activation energy of thermal quenching was also found to decrease with increase in annealing temperature. Thermally assisted optically stimulated luminescence measurement was carried out using continuous wave optical stimulated luminescence (CW-OSL). The samples studied were those annealed at 500̊C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The CW-OSL is stimulated using 470 nm blue LEDs at sample temperatures between 30 and 200̊C. It is measured after preheating to either 300 and 500̊C. When the integrated OSL intensity is plotted as a function of measurement temperature, the intensity goes through a peak. The increase in OSL intensity as a function of temperature is associated to thermal assistance and the decrease to thermal quenching. The kinetic parameters were evaluated by fitting the experimental data. The values of activation energies of thermal quenching are the same within experimental uncertainties for all the experimental conditions. This shows that annealing temperature, duration of annealing and irradiation dose have a negligible influence on the recombination site of luminescence using OSL. Phototransferred thermoluminescence (PTTL) induced from annealed samples using 470 nm blue light was also investigated. The quartz were annealed at 500 _C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The glow curves of conventional TL measured at 1 _C s1 following irradiation to 200 Gy shows six peaks in each case labelled I-VI for ease of reference whereas peaks observed under PTTL are referred to as A1 onwards. Only the first three peaks were reproduced under phototransfer for the sample annealed at 900̊C for 60 minutes and 1000̊C C for 10 minutes. Interestingly, for the intermediate duration of annealing of 30 minutes, the only peak that appears under phototransfer is the A1. For quartz annealed at 900̊C for 10 minutes, the PTTL appears as long as the preheating temperature does not exceed 560̊C. All other annealing temperatures, PTTL only appears for preheating to 450 and below. This shows that the occupancy of deep electron traps at temperatures beyond 450̊C or 560̊C is low. The activation energy for peaks A1, A2 and A3 were calculated. The PTTL peaks were studied for thermal quenching and peaks A1 and A3 were found to be affected. The activation energies for thermal quenching were determined as 0.62 ± 0.04 eV and 0.65 ± 0.02 eV for peaks A1 and A3 respectively. The experimental dependence of PTTL intensity on illumination time is modelled using sets of coupled linear differential equations based on systems of donors and acceptors whose number is determined by preheating temperature.
- Full Text:
- Date Issued: 2020
- Authors: Dawam, Robert Rangmou
- Date: 2020
- Subjects: Thermoluminescence , Quartz
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145849 , vital:38472
- Description: The main aim of this investigation is on thermoluminescence and phototransferred thermoluminescence of synthetic quartz. Thermoluminescence was one of the tools used in characterising the electron traps parameters. The samples of quartz annealed at various temperatures up to 900̊C and the unannealed were used. The thermoluminescence glow curve was measured at 1̊C s~ 1 following beta irradiation to 40 Gy from the samples annealed at 500̊C and the unannealed consist of main peak at 70̊C and secondary peaks at 110, 180 and 310̊C. In comparison, the thermoluminescence glow curve for the sample annealed at 900̊C have main peak at 86̊C and the secondary ones at 170 and 310̊C. The kinetic analysis was carried out only on the main peak in each case. The activation energy was found to be decreasing with increase in annealing temperatures. The samples annealed at 500̊C and the unannealed were found to be affected by thermal quenching while sample annealed at 900̊C shows an inverse quenching for irradiation dose of 40 Gy. However, when the dose was reduce to 3 Gy the effects of thermal quenching was manifested. The activation energy of thermal quenching was also found to decrease with increase in annealing temperature. Thermally assisted optically stimulated luminescence measurement was carried out using continuous wave optical stimulated luminescence (CW-OSL). The samples studied were those annealed at 500̊C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The CW-OSL is stimulated using 470 nm blue LEDs at sample temperatures between 30 and 200̊C. It is measured after preheating to either 300 and 500̊C. When the integrated OSL intensity is plotted as a function of measurement temperature, the intensity goes through a peak. The increase in OSL intensity as a function of temperature is associated to thermal assistance and the decrease to thermal quenching. The kinetic parameters were evaluated by fitting the experimental data. The values of activation energies of thermal quenching are the same within experimental uncertainties for all the experimental conditions. This shows that annealing temperature, duration of annealing and irradiation dose have a negligible influence on the recombination site of luminescence using OSL. Phototransferred thermoluminescence (PTTL) induced from annealed samples using 470 nm blue light was also investigated. The quartz were annealed at 500 _C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The glow curves of conventional TL measured at 1 _C s1 following irradiation to 200 Gy shows six peaks in each case labelled I-VI for ease of reference whereas peaks observed under PTTL are referred to as A1 onwards. Only the first three peaks were reproduced under phototransfer for the sample annealed at 900̊C for 60 minutes and 1000̊C C for 10 minutes. Interestingly, for the intermediate duration of annealing of 30 minutes, the only peak that appears under phototransfer is the A1. For quartz annealed at 900̊C for 10 minutes, the PTTL appears as long as the preheating temperature does not exceed 560̊C. All other annealing temperatures, PTTL only appears for preheating to 450 and below. This shows that the occupancy of deep electron traps at temperatures beyond 450̊C or 560̊C is low. The activation energy for peaks A1, A2 and A3 were calculated. The PTTL peaks were studied for thermal quenching and peaks A1 and A3 were found to be affected. The activation energies for thermal quenching were determined as 0.62 ± 0.04 eV and 0.65 ± 0.02 eV for peaks A1 and A3 respectively. The experimental dependence of PTTL intensity on illumination time is modelled using sets of coupled linear differential equations based on systems of donors and acceptors whose number is determined by preheating temperature.
- Full Text:
- Date Issued: 2020
Towards a community-based model for Agricultural development in Uganda : a case study of Kumi and Gomba districts
- Authors: Kiggundu, Joseph
- Date: 2020
- Subjects: Agricultural development projects -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48654 , vital:41056
- Description: This study intended to design a community-based model for agricultural development in Uganda, using Kumi and Gomba districts as case studies. The surge in attention towards community-based development is attributed to the growing challenges posed by the traditional approaches to community development, dominated by top-down mechanisms during the planning, implementation, management, monitoring, and evaluation phases of community development programmes. Driven by Robert Chambers and Conway’s theoretical perspectives, this study discusses that a community-based model is capable of filling knowledge gaps, not only in scientific research, but also in the community development process of many developing nations, such as Uganda. In this study particularly, a community-based approach has been identified as the better option in aiding and facilitating the current government efforts to transform the agricultural sector from its predominantly subsistence nature to commercial orientation. It has been acknowledged that the Ugandan government and its development partners do realise the significant role agriculture plays in directly or indirectly impacting the social welfare of Ugandans. The agricultural sector has been identified as a major source of livelihood for most rural Ugandans (over 95% depend on it for food, employment and income). Unfortunately, even with such recognition, coupled with many reforms initiated by government and supported by various development partners who have invested huge sums of money into the sector, agricultural productivity and profitability has remained extremely low. Most rural Ugandans still languish in abject poverty, hunger, malnutrition, vulnerability and powerlessness. This study has established that, while the agricultural sector in Uganda suffers from enormous institutional, technological, market, research and land-oriented challenges, if all these factors are kept constant, an effective community-based approach is capable of facilitating effective planning, implementation, management, monitoring, and evaluation of agricultural reforms, for increased agricultural productivity and profitability hence the improved quality of life of Ugandans. A qualitative elicitation interviewing technique involving in-depth discussions with agricultural extension workers, community development officers, representatives from NGOs, local farmers, farmers’ associations, local and religious leaders as well as key persons from the Ministry of Agriculture and other line ministries was conducted. The participants were selected through chain referrals until the level of theoretical saturation. In addition, directed field observations, document analysis and key informant interviews with other respondents selected through theoretical sampling enhanced the robustness of data acquisition methods. Group-based participatory data analysis and reflexive pragmatism also enhanced the rigour and quality of research findings intended to balance the knowledge generated from the recognised scientific audience and the views of the important but unknown “knowledge generators” (the local experts).The key findings indicate that, historically and currently, agriculture has been and is the predominant community development activity at household, community and national levels in Uganda. It is also anticipated that agriculture will remain a major contributor to the national economic development of Uganda even over the next hundred years. The efforts by government and its development partners to transform the sector are therefore justified by the sector’s strategic importance. It has been found out that although the sector faces huge challenges, there are numerous opportunities for the sector to become a driver of Uganda’s socio-economic development. A community-based model has been proposed as a viable option for facilitating faster agricultural development in Uganda, where technocratic developers tend to impose development reforms on local people. With the traditional approaches to planning and implementation, it was thought that local people do not know what they want, they are illiterate and ignorant and therefore incapable of driving government crafted programmes for effective change. From the proposed model, government technocratic development agents should engage local farmers who practically experience poverty, powerlessness, hunger, malnutrition and vulnerability, to jointly craft effective agricultural reforms that are not only life-changing, but also relevant and sustainable within the confines of community needs. Under this approach, the designers, planners, implementers, monitors, and evaluators, whether of government-initiated reforms, or initiatives from other development agencies, should learn to treat local people as subjects of the community development processes, as opposed to the traditional top-down mechanisms which view them as objects to be used and abused. The involvement of local experts during the planning, implementation, and management of development reforms, should cease to be applied as merely routine fulfilment of donor conditionality and requirements. Rather, the participation of local farmers during all phases of community programming should become intentional and consciously aimed at empowering local people to actively participate in the making of decisions critical to their own development.
- Full Text:
- Date Issued: 2020
- Authors: Kiggundu, Joseph
- Date: 2020
- Subjects: Agricultural development projects -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48654 , vital:41056
- Description: This study intended to design a community-based model for agricultural development in Uganda, using Kumi and Gomba districts as case studies. The surge in attention towards community-based development is attributed to the growing challenges posed by the traditional approaches to community development, dominated by top-down mechanisms during the planning, implementation, management, monitoring, and evaluation phases of community development programmes. Driven by Robert Chambers and Conway’s theoretical perspectives, this study discusses that a community-based model is capable of filling knowledge gaps, not only in scientific research, but also in the community development process of many developing nations, such as Uganda. In this study particularly, a community-based approach has been identified as the better option in aiding and facilitating the current government efforts to transform the agricultural sector from its predominantly subsistence nature to commercial orientation. It has been acknowledged that the Ugandan government and its development partners do realise the significant role agriculture plays in directly or indirectly impacting the social welfare of Ugandans. The agricultural sector has been identified as a major source of livelihood for most rural Ugandans (over 95% depend on it for food, employment and income). Unfortunately, even with such recognition, coupled with many reforms initiated by government and supported by various development partners who have invested huge sums of money into the sector, agricultural productivity and profitability has remained extremely low. Most rural Ugandans still languish in abject poverty, hunger, malnutrition, vulnerability and powerlessness. This study has established that, while the agricultural sector in Uganda suffers from enormous institutional, technological, market, research and land-oriented challenges, if all these factors are kept constant, an effective community-based approach is capable of facilitating effective planning, implementation, management, monitoring, and evaluation of agricultural reforms, for increased agricultural productivity and profitability hence the improved quality of life of Ugandans. A qualitative elicitation interviewing technique involving in-depth discussions with agricultural extension workers, community development officers, representatives from NGOs, local farmers, farmers’ associations, local and religious leaders as well as key persons from the Ministry of Agriculture and other line ministries was conducted. The participants were selected through chain referrals until the level of theoretical saturation. In addition, directed field observations, document analysis and key informant interviews with other respondents selected through theoretical sampling enhanced the robustness of data acquisition methods. Group-based participatory data analysis and reflexive pragmatism also enhanced the rigour and quality of research findings intended to balance the knowledge generated from the recognised scientific audience and the views of the important but unknown “knowledge generators” (the local experts).The key findings indicate that, historically and currently, agriculture has been and is the predominant community development activity at household, community and national levels in Uganda. It is also anticipated that agriculture will remain a major contributor to the national economic development of Uganda even over the next hundred years. The efforts by government and its development partners to transform the sector are therefore justified by the sector’s strategic importance. It has been found out that although the sector faces huge challenges, there are numerous opportunities for the sector to become a driver of Uganda’s socio-economic development. A community-based model has been proposed as a viable option for facilitating faster agricultural development in Uganda, where technocratic developers tend to impose development reforms on local people. With the traditional approaches to planning and implementation, it was thought that local people do not know what they want, they are illiterate and ignorant and therefore incapable of driving government crafted programmes for effective change. From the proposed model, government technocratic development agents should engage local farmers who practically experience poverty, powerlessness, hunger, malnutrition and vulnerability, to jointly craft effective agricultural reforms that are not only life-changing, but also relevant and sustainable within the confines of community needs. Under this approach, the designers, planners, implementers, monitors, and evaluators, whether of government-initiated reforms, or initiatives from other development agencies, should learn to treat local people as subjects of the community development processes, as opposed to the traditional top-down mechanisms which view them as objects to be used and abused. The involvement of local experts during the planning, implementation, and management of development reforms, should cease to be applied as merely routine fulfilment of donor conditionality and requirements. Rather, the participation of local farmers during all phases of community programming should become intentional and consciously aimed at empowering local people to actively participate in the making of decisions critical to their own development.
- Full Text:
- Date Issued: 2020
Towards development of a malaria diagnostic: Generation, screening and validation of novel aptamers recognising Plasmodium falciparum lactate dehydrogenase
- Authors: Frith, Kelly-Anne
- Date: 2020
- Subjects: Plasmodium falciparum , Malaria -- Chemotherapy , Oligonucleotides , Lactate dehydrogenase , Biochemical markers , Systematic evolution of ligands through exponential enrichment (SELEX)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142247 , vital:38062
- Description: Malaria, caused by infection with the Plasmodium parasite, is one of the leading causes of death in under-developed countries. Early detection is crucial for the effective treatment of malaria, particularly in cases where infection is due to Plasmodium falciparum. There is, therefore, an enduring need for portable, sensitive, reliable, accurate, durable, self-validating and cost-effective techniques for the rapid detection of malaria. Moreover, there is a demand to distinguish between various infectious species causing malaria. Research in the area of malarial biomarkers has identified a unique, species-specific, epitope of P. falciparum lactate dehydrogenase (PfLDH), enhancing prospects for the development of diagnostics capable of identifying the species causing malarial infection. In recent years, improvements have been made towards the development of rapid diagnostic tests for detecting malarial biomarkers. Owing to their low cost, ease of labeling, and high thermal stability (relative to antibodies), the development and synthesis of aptamers that target the malarial lactate dehydrogenase represents one of the key innovations in the field of rapid diagnostics for malaria. This study explored the generation of aptamers that specifically target P. falciparum. Two sets of aptamers with diagnostically-supportive functions were generated independently, through parallel SELEX of recombinantly-expressed, full-length Plasmodium falciparum lactate dehydrogenase (rPfLDH), and an oligopeptide comprising the P. falciparum-specific epitope on lactate dehydrogenase (LDHp). The latter offers a promising solution for generating aptamers capable of binding with high specificity to P. falciparum. In this work, an rLDH class of aptamers was generated when SELEX was performed using the full-length rPfLDH protein as the target and the LDHp class of aptamers was generated when SELEX was performed using the oligopeptide LDHp as a target. Aptamers were successfully generated through the process of SELEX (systematic evolution of ligands through exponential enrichment) following the study and application of several optimisation steps, particularly during the amplification stage of SELEX. Optimisation steps included the study of improvements in PCR conditions; role of surfactants (Triton-X), modifying the PCR clean-up protocol; and agarose gel excision. Structurally-relevant moieties with particular consensus sequences (GGTAG and GGCG) were found in aptamers both reported here and previously published, confirming their importance in recognition of the target. Novel moieties particular to this work (ATTAT and poly-A stretches) were identified. Clades of consensus sequences were identified in both the rLDH and LDHp groups of aptamers, where sequences in the rLDH clade did not show preferential binding to rPfLDH while those in the LDHp clade (particularly LDHp 3 and 18) were able to recognise and bind only LDHp. Of the 19 sequences returned from the parallel SELEX procedures for rPfLDH (11 sequences) and LDHp (8 sequences), six rPfLDH and all eight LDHp sequences underwent preliminary screening and those with low responses eliminated. Of the eight LDHp-targeting aptamer sequences, five were preliminarily shown to bind to LDHp, whereas only two rPfLDH-targeting sequences were shown to bind to the target (rLDH 4 and 7). To this small selection of rPfLDH oligonucleotide sequences, two more (rLDH 1 and 15) were chosen for further study based on their sequences, secondary and predicted tertiary conformations. Sequences chosen for further study were therefore: rLDH 1, 4, 7 and 15 in the rLDH class, and LDHp 1, 3, 11, 14 and 18 in the LDHp class. Binding properties of the aptamers towards their targets were investigated using enzyme-linked oligonucleotide assays (ELONA), fluorophore-linked oligonucleotide assays (FLONA), electromobility shift assays (EMSA), surface plasmon resonance (SPR), and GelRed dissociation assays, while applications towards aptasensors were explored using electrochemical impedance spectroscopy (EIS) and fluorescent microscopy. Some inconsistencies were seen for specific aptamer to target binding interactions using specific techniques; however, generally, binding to the targets was observed across the techniques assessed. These varied responses demonstrate the need to screen and validate aptamers using a variety of techniques and platforms not necessarily specific for the proposed application. From the aptamer binding screening studies using ELONA, the most promising aptamers generated were identified as LDHp 11, rLDH 4, rLDH 7 and rLDH 15. Aptamer rLDH 4, which was generated against rPfLDH, exhibited preferential and specific binding to the lactate dehydrogenase from P. falciparum, over the recombinantly-expressed lactate dehydrogenase from Plasmodium vivax (rPvLDH), albeit with lowered responses compared to LDHp 11 in ELONA and EMSA studies. However, in kinetic ELONA studies rLDH 4 showed binding to both rPfLDH and rPvLDH. Aptamer rLDH 7 showed high affinity for rPfLDH and rPvLDH in kinetic studies using ELONA. However, screening studies with ELONA indicates that aptamer rLDH 7 may not be suitable for diagnostic tests in serum samples given its non-specific binding to human serum albumin (HSA). Aptamer rLDH 15 exhibited species specificity for rPfLDH in screening studies using ELONA but showed affinity towards rPvLDH (albeit lower relative to its affinity for rPfLDH) in kinetic studies using ELONA. LDHp 11, generated against the PfLDH peptide, showed a clear preference for rPfLDH when compared to rPvLDH and other control proteins, in both sets of ELONA studies conducted, as well as EMSA, thus possessing a strong ability to identify the presence of Plasmodium falciparum owing to its generation against the species-specific epitope. While LDHp 1 demonstrated binding to plasmodial LDH in a flow-through system (SPR), so reiterating ELONA responses, it did not perform well in the remaining methodologies. Aptamers rLDH 1 and 15 and LDHp 3, 14 and 18 exhibited a mixed set of results throughout the target protein screening analyses and were, thus, not considered for selective binding in P. falciparum parasite bodies. In studies aimed at exploring biosensor assemblies utilising the developed aptamers, both rLDH 4 and LDHp 11, along with rLDH 7, LDHp 1 and pL1, demonstrated in situ binding to the native PfLDH in fluorescent microscopy. LDHp 11 exhibited FITC-based fluorescence equivalent to the anti-rPfLDHp IgY antibody in confocal fluorescent microscopy indicating superior binding to the native PfLDH compared to the remaining aptamers. An examination of electrochemical impedance as a platform for a biosensor assembly did not, in these studies, exhibit the required sensitivity using physiologically relevant concentrations of analyte expected for pLDH following infection with Plasmodium spp. Malstat/LDH activity was explored for application in a colorimetric aptasensor. A decrease in both rPfLDH and rPvLDH activity was observed following incubation with the tested aptamers, but rLDH 1, rLDH 7 and LDHp 14 did not exhibit similar decreases in rPvLDH activity. Aptamers rLDH 1, 4 and 7 and LDHp 11 and 14 were, therefore, not selected as candidates for LDH capture in LDH activity-based diagnostic devices for P. falciparum. The decreases in pLDH activity in the presence of aptamers could hold promise as direct or antagonistic malaria therapeutic agents. Preliminary studies on the application of aptamers as malaria therapeutic agents, while of interest, should be viewed with due caution given the challenges of aptamers reaching the intracellular native plasmodial LDH hosted within the red blood cells. In conclusion, this work has shown the ability of the LDHp 11 aptamer, generated in these studies, to selectively bind rPfLDH over rPvLDH, and to bind to the native PfLDH in fluorescent microscopy, indicating that this aptamer holds promise as a biorecognition element in malaria biosensors and other diagnostic devices for the detection, and differentiation, of P. falciparum and P. vivax. The use of a species-specific epitope of P. falciparum as a target in aptamer generation paves the way for similar such studies aimed at generating aptamers with species selectivity for other Plasmodium species.
- Full Text:
- Date Issued: 2020
- Authors: Frith, Kelly-Anne
- Date: 2020
- Subjects: Plasmodium falciparum , Malaria -- Chemotherapy , Oligonucleotides , Lactate dehydrogenase , Biochemical markers , Systematic evolution of ligands through exponential enrichment (SELEX)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142247 , vital:38062
- Description: Malaria, caused by infection with the Plasmodium parasite, is one of the leading causes of death in under-developed countries. Early detection is crucial for the effective treatment of malaria, particularly in cases where infection is due to Plasmodium falciparum. There is, therefore, an enduring need for portable, sensitive, reliable, accurate, durable, self-validating and cost-effective techniques for the rapid detection of malaria. Moreover, there is a demand to distinguish between various infectious species causing malaria. Research in the area of malarial biomarkers has identified a unique, species-specific, epitope of P. falciparum lactate dehydrogenase (PfLDH), enhancing prospects for the development of diagnostics capable of identifying the species causing malarial infection. In recent years, improvements have been made towards the development of rapid diagnostic tests for detecting malarial biomarkers. Owing to their low cost, ease of labeling, and high thermal stability (relative to antibodies), the development and synthesis of aptamers that target the malarial lactate dehydrogenase represents one of the key innovations in the field of rapid diagnostics for malaria. This study explored the generation of aptamers that specifically target P. falciparum. Two sets of aptamers with diagnostically-supportive functions were generated independently, through parallel SELEX of recombinantly-expressed, full-length Plasmodium falciparum lactate dehydrogenase (rPfLDH), and an oligopeptide comprising the P. falciparum-specific epitope on lactate dehydrogenase (LDHp). The latter offers a promising solution for generating aptamers capable of binding with high specificity to P. falciparum. In this work, an rLDH class of aptamers was generated when SELEX was performed using the full-length rPfLDH protein as the target and the LDHp class of aptamers was generated when SELEX was performed using the oligopeptide LDHp as a target. Aptamers were successfully generated through the process of SELEX (systematic evolution of ligands through exponential enrichment) following the study and application of several optimisation steps, particularly during the amplification stage of SELEX. Optimisation steps included the study of improvements in PCR conditions; role of surfactants (Triton-X), modifying the PCR clean-up protocol; and agarose gel excision. Structurally-relevant moieties with particular consensus sequences (GGTAG and GGCG) were found in aptamers both reported here and previously published, confirming their importance in recognition of the target. Novel moieties particular to this work (ATTAT and poly-A stretches) were identified. Clades of consensus sequences were identified in both the rLDH and LDHp groups of aptamers, where sequences in the rLDH clade did not show preferential binding to rPfLDH while those in the LDHp clade (particularly LDHp 3 and 18) were able to recognise and bind only LDHp. Of the 19 sequences returned from the parallel SELEX procedures for rPfLDH (11 sequences) and LDHp (8 sequences), six rPfLDH and all eight LDHp sequences underwent preliminary screening and those with low responses eliminated. Of the eight LDHp-targeting aptamer sequences, five were preliminarily shown to bind to LDHp, whereas only two rPfLDH-targeting sequences were shown to bind to the target (rLDH 4 and 7). To this small selection of rPfLDH oligonucleotide sequences, two more (rLDH 1 and 15) were chosen for further study based on their sequences, secondary and predicted tertiary conformations. Sequences chosen for further study were therefore: rLDH 1, 4, 7 and 15 in the rLDH class, and LDHp 1, 3, 11, 14 and 18 in the LDHp class. Binding properties of the aptamers towards their targets were investigated using enzyme-linked oligonucleotide assays (ELONA), fluorophore-linked oligonucleotide assays (FLONA), electromobility shift assays (EMSA), surface plasmon resonance (SPR), and GelRed dissociation assays, while applications towards aptasensors were explored using electrochemical impedance spectroscopy (EIS) and fluorescent microscopy. Some inconsistencies were seen for specific aptamer to target binding interactions using specific techniques; however, generally, binding to the targets was observed across the techniques assessed. These varied responses demonstrate the need to screen and validate aptamers using a variety of techniques and platforms not necessarily specific for the proposed application. From the aptamer binding screening studies using ELONA, the most promising aptamers generated were identified as LDHp 11, rLDH 4, rLDH 7 and rLDH 15. Aptamer rLDH 4, which was generated against rPfLDH, exhibited preferential and specific binding to the lactate dehydrogenase from P. falciparum, over the recombinantly-expressed lactate dehydrogenase from Plasmodium vivax (rPvLDH), albeit with lowered responses compared to LDHp 11 in ELONA and EMSA studies. However, in kinetic ELONA studies rLDH 4 showed binding to both rPfLDH and rPvLDH. Aptamer rLDH 7 showed high affinity for rPfLDH and rPvLDH in kinetic studies using ELONA. However, screening studies with ELONA indicates that aptamer rLDH 7 may not be suitable for diagnostic tests in serum samples given its non-specific binding to human serum albumin (HSA). Aptamer rLDH 15 exhibited species specificity for rPfLDH in screening studies using ELONA but showed affinity towards rPvLDH (albeit lower relative to its affinity for rPfLDH) in kinetic studies using ELONA. LDHp 11, generated against the PfLDH peptide, showed a clear preference for rPfLDH when compared to rPvLDH and other control proteins, in both sets of ELONA studies conducted, as well as EMSA, thus possessing a strong ability to identify the presence of Plasmodium falciparum owing to its generation against the species-specific epitope. While LDHp 1 demonstrated binding to plasmodial LDH in a flow-through system (SPR), so reiterating ELONA responses, it did not perform well in the remaining methodologies. Aptamers rLDH 1 and 15 and LDHp 3, 14 and 18 exhibited a mixed set of results throughout the target protein screening analyses and were, thus, not considered for selective binding in P. falciparum parasite bodies. In studies aimed at exploring biosensor assemblies utilising the developed aptamers, both rLDH 4 and LDHp 11, along with rLDH 7, LDHp 1 and pL1, demonstrated in situ binding to the native PfLDH in fluorescent microscopy. LDHp 11 exhibited FITC-based fluorescence equivalent to the anti-rPfLDHp IgY antibody in confocal fluorescent microscopy indicating superior binding to the native PfLDH compared to the remaining aptamers. An examination of electrochemical impedance as a platform for a biosensor assembly did not, in these studies, exhibit the required sensitivity using physiologically relevant concentrations of analyte expected for pLDH following infection with Plasmodium spp. Malstat/LDH activity was explored for application in a colorimetric aptasensor. A decrease in both rPfLDH and rPvLDH activity was observed following incubation with the tested aptamers, but rLDH 1, rLDH 7 and LDHp 14 did not exhibit similar decreases in rPvLDH activity. Aptamers rLDH 1, 4 and 7 and LDHp 11 and 14 were, therefore, not selected as candidates for LDH capture in LDH activity-based diagnostic devices for P. falciparum. The decreases in pLDH activity in the presence of aptamers could hold promise as direct or antagonistic malaria therapeutic agents. Preliminary studies on the application of aptamers as malaria therapeutic agents, while of interest, should be viewed with due caution given the challenges of aptamers reaching the intracellular native plasmodial LDH hosted within the red blood cells. In conclusion, this work has shown the ability of the LDHp 11 aptamer, generated in these studies, to selectively bind rPfLDH over rPvLDH, and to bind to the native PfLDH in fluorescent microscopy, indicating that this aptamer holds promise as a biorecognition element in malaria biosensors and other diagnostic devices for the detection, and differentiation, of P. falciparum and P. vivax. The use of a species-specific epitope of P. falciparum as a target in aptamer generation paves the way for similar such studies aimed at generating aptamers with species selectivity for other Plasmodium species.
- Full Text:
- Date Issued: 2020
Transformative ICT education practices in rural secondary schools for developmental needs and realities: the Eastern Cape Province, South Africa
- Authors: Simuja, Clement
- Date: 2020
- Subjects: Education, Secondary -- South Africa -- Data processing , Information technology -- Study and teaching (Secondary) --South Africa , Educational technology -- Developing countries , Rural development -- Developing countries , Computer-assisted instruction -- South Africa -- Eastern Cape , Internet in education -- South Africa , Rural schools -- South Africa -- Eastern Cape , Community and school -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150631 , vital:38991
- Description: The perceived social development significance of Information and Communication Technology (ICT) has dramatically expanded the domains in which this cluster of ICTs is being discussed and acted upon. The action to promote community development in rural areas in South Africa has made its way into the introduction of ICT education in secondary schools. Since rural secondary schools form part of the framework for rural communities, they are being challenged to provide ICT education that makes a difference in learners’ lives. This requires engaging education practices that inspire learners to construct knowledge of ICT that does not only respond to examination purposes but rather, to the needs and development aspirations of the community. This research examines the experience of engaging learners and communities in socially informed ICT education in rural secondary schools. Specifically, it seeks to develop a critique of current practices involved in ICT education in rural secondary schools, and explores plausible alternatives to such practices that would make ICT education more transformative and structured towards the developmental concerns of communities. The main empirical focus for the research was five rural secondary schools in the Eastern Cape Province in South Africa. The research involved 53 participants that participated in a socially informed ICT training process. The training was designed to inspire participants to share their self-defined ICT education and ICT knowledge experiences. Critical Action Learning and Philosophical Inquiry provided the methodological framework, whilst the theoretical framework draws on Foucault’s philosophical ideas on power-knowledge relations. Through this theoretical analysis, the research examines the dynamic interplay of practices in ICT education with the values, ideals, and knowledge that form the core-life experiences of learners and rural communities. The research findings of this study indicate that current ICT education practices in rural secondary schools are endowed with ideologies that are affecting learners’ identity, social experiences, power, and ownership of the reflective meaning of using ICTs in community development. The contribution of this thesis lies in demonstrating ways that reframe ICT education transformatively, and more specifically its practices in the light of the way power, identity, ownership and social experience construct and offer learners a transformative view of self and the world. This could enable ICT education to fulfil the potential of contributing to social development in rural communities. The thesis culminates by presenting a theoretical framework that articulates the structural and authoritative components of ICT education practices – these relate to learners’ conscious understandings and represented thoughts, sensations and meanings embedded in the context, and actions and locations of using their knowledge of ICT.
- Full Text:
- Date Issued: 2020
- Authors: Simuja, Clement
- Date: 2020
- Subjects: Education, Secondary -- South Africa -- Data processing , Information technology -- Study and teaching (Secondary) --South Africa , Educational technology -- Developing countries , Rural development -- Developing countries , Computer-assisted instruction -- South Africa -- Eastern Cape , Internet in education -- South Africa , Rural schools -- South Africa -- Eastern Cape , Community and school -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150631 , vital:38991
- Description: The perceived social development significance of Information and Communication Technology (ICT) has dramatically expanded the domains in which this cluster of ICTs is being discussed and acted upon. The action to promote community development in rural areas in South Africa has made its way into the introduction of ICT education in secondary schools. Since rural secondary schools form part of the framework for rural communities, they are being challenged to provide ICT education that makes a difference in learners’ lives. This requires engaging education practices that inspire learners to construct knowledge of ICT that does not only respond to examination purposes but rather, to the needs and development aspirations of the community. This research examines the experience of engaging learners and communities in socially informed ICT education in rural secondary schools. Specifically, it seeks to develop a critique of current practices involved in ICT education in rural secondary schools, and explores plausible alternatives to such practices that would make ICT education more transformative and structured towards the developmental concerns of communities. The main empirical focus for the research was five rural secondary schools in the Eastern Cape Province in South Africa. The research involved 53 participants that participated in a socially informed ICT training process. The training was designed to inspire participants to share their self-defined ICT education and ICT knowledge experiences. Critical Action Learning and Philosophical Inquiry provided the methodological framework, whilst the theoretical framework draws on Foucault’s philosophical ideas on power-knowledge relations. Through this theoretical analysis, the research examines the dynamic interplay of practices in ICT education with the values, ideals, and knowledge that form the core-life experiences of learners and rural communities. The research findings of this study indicate that current ICT education practices in rural secondary schools are endowed with ideologies that are affecting learners’ identity, social experiences, power, and ownership of the reflective meaning of using ICTs in community development. The contribution of this thesis lies in demonstrating ways that reframe ICT education transformatively, and more specifically its practices in the light of the way power, identity, ownership and social experience construct and offer learners a transformative view of self and the world. This could enable ICT education to fulfil the potential of contributing to social development in rural communities. The thesis culminates by presenting a theoretical framework that articulates the structural and authoritative components of ICT education practices – these relate to learners’ conscious understandings and represented thoughts, sensations and meanings embedded in the context, and actions and locations of using their knowledge of ICT.
- Full Text:
- Date Issued: 2020
Ultra-high precision diamond turning of advanced contact lens polymers
- Authors: Liman, Muhammad Mukhtar
- Date: 2020
- Subjects: Contact lenses , Electrostatic lenses Lenses -- Design and construction
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46108 , vital:39496
- Description: Contact lens polymer-based materials are extensively used in the optical industry owing to their excellent corrosion resistance, the possibility of mass production and their ability to be processed without external lubrication. Owing to the fast growth in optical industries, contact lens (CL) requires high accuracy and a high surface quality. The demand for high-accuracy and minimal surface roughness drives the development of ultra-high precision machining technology with regard to single point diamond turning (SPDT). Ultra-high precision diamond turning is an advanced manufacturing technique employed in the machining of CLs owing to its capability of producing high optical surfaces with complex shapes and nanometric accuracy. Yet, even with the advances in ultra-high precision machining (UHPM), it is not continuously easy to achieve a highquality surface finish during polymers machining as the adhesion of the tool chip around the tool dictates the presence of electrostatic charges. The electrostatic charges encountered by a cutting tool when turning advanced CLs are important as they reflect the quality and condition of the tool, machine, fixture, and sometimes even the finished surface, which is responsible for tool wear and poor surface quality. This study investigates the role of cutting parameters, namely cutting speed, feed rate and depth of cut on surface roughness (Ra), electrostatic charge (ESC) and material removal rate (MRR), which determines machine economics and the quality of machining contact lens polymers. The experiments were mainly conducted on two different advanced polymeric materials: polymethyl methacrylate (PMMA) and Optimum Extreme (Roflufocon E) CLs. Experimentation was carried out on the Nanoform 250 ultra-grind turning machine with a monocrystalline diamond-cutting tool for machining the PMMA and Roflufocon E CL polymers, covering a wide range of machining parameters. Before conducting the experiments, a design of experiment was conducted according to the response surface methodology (RSM) that is based on the Box-Behnken Design (BBD). In addition, the research study focused on the determination of the optimum cutting conditions leading to minimum Ra and ESC as well as maximum productivity in the SPDT of the PMMA and Roflufocon E CL polymers, using a monocrystalline diamondcutting tool. The optimization was based on RSM together with the desirability function approach. In addition, a mathematical model was developed for Ra, ESC and MRR using a RSM regression analysis for PMMA and Roflufocon E CL polymers by means of Design Expert software. RSM allowed for the optimization of the cutting conditions for minimal Ra and ESC as well as maximal MRR, which provides an effective knowledge base for process parameters to enhance process performance in the SPDT of CL polymers. Furthermore, this study also deals with the development of Ra, ESC and MRR prediction models for the diamond turning of PMMA and Roflufocon E CL polymers, using the fuzzy logic based artificial intelligence (AI) method. The fuzzy logic model has been developed in terms of machining parameters for the prediction of Ra, ESC and MRR. To judge the accuracy and ability of the fuzzy logic model, an average percentage error was used. The comparative evaluation of experiments and the fuzzy logic approach suggested that the obtained average errors of Ra, ESC and MRR using the fuzzy logic system were in agreement with the experimental results. Hence, the developed fuzzy logic rules can be effectively utilized to predict the ESC, Ra and MRR of PMMA and Roflufocon E CL polymers in automated optical manufacturing environments for high accuracy and a reduction of computational cost. Moreover, owing to the brittle nature of optical polymers, the Roflufocon E CL polymer requires ductile-mode machining for improved surface quality. Molecular Dynamics (MD) simulation methods are thus applied to investigate the atomistic reaction at the tool/workpiece surface to clearly study and observe conditions occurring at nanometric scale in polymer machining. This research study is particularly concerned with the comparative analysis of experiments and a MD study of the Roflufocon E optical polymer nano cutting approach to the atomistic visualization of the plastic material flow at the tool/workpiece interface during cutting. The simulated MD acting force, machine stresses, and the temperature at the cutting region were evaluated to access the accuracy of the model. Hence, the nanomachining simulations were found to have a correlation to the experimental machining results.
- Full Text:
- Date Issued: 2020
- Authors: Liman, Muhammad Mukhtar
- Date: 2020
- Subjects: Contact lenses , Electrostatic lenses Lenses -- Design and construction
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46108 , vital:39496
- Description: Contact lens polymer-based materials are extensively used in the optical industry owing to their excellent corrosion resistance, the possibility of mass production and their ability to be processed without external lubrication. Owing to the fast growth in optical industries, contact lens (CL) requires high accuracy and a high surface quality. The demand for high-accuracy and minimal surface roughness drives the development of ultra-high precision machining technology with regard to single point diamond turning (SPDT). Ultra-high precision diamond turning is an advanced manufacturing technique employed in the machining of CLs owing to its capability of producing high optical surfaces with complex shapes and nanometric accuracy. Yet, even with the advances in ultra-high precision machining (UHPM), it is not continuously easy to achieve a highquality surface finish during polymers machining as the adhesion of the tool chip around the tool dictates the presence of electrostatic charges. The electrostatic charges encountered by a cutting tool when turning advanced CLs are important as they reflect the quality and condition of the tool, machine, fixture, and sometimes even the finished surface, which is responsible for tool wear and poor surface quality. This study investigates the role of cutting parameters, namely cutting speed, feed rate and depth of cut on surface roughness (Ra), electrostatic charge (ESC) and material removal rate (MRR), which determines machine economics and the quality of machining contact lens polymers. The experiments were mainly conducted on two different advanced polymeric materials: polymethyl methacrylate (PMMA) and Optimum Extreme (Roflufocon E) CLs. Experimentation was carried out on the Nanoform 250 ultra-grind turning machine with a monocrystalline diamond-cutting tool for machining the PMMA and Roflufocon E CL polymers, covering a wide range of machining parameters. Before conducting the experiments, a design of experiment was conducted according to the response surface methodology (RSM) that is based on the Box-Behnken Design (BBD). In addition, the research study focused on the determination of the optimum cutting conditions leading to minimum Ra and ESC as well as maximum productivity in the SPDT of the PMMA and Roflufocon E CL polymers, using a monocrystalline diamondcutting tool. The optimization was based on RSM together with the desirability function approach. In addition, a mathematical model was developed for Ra, ESC and MRR using a RSM regression analysis for PMMA and Roflufocon E CL polymers by means of Design Expert software. RSM allowed for the optimization of the cutting conditions for minimal Ra and ESC as well as maximal MRR, which provides an effective knowledge base for process parameters to enhance process performance in the SPDT of CL polymers. Furthermore, this study also deals with the development of Ra, ESC and MRR prediction models for the diamond turning of PMMA and Roflufocon E CL polymers, using the fuzzy logic based artificial intelligence (AI) method. The fuzzy logic model has been developed in terms of machining parameters for the prediction of Ra, ESC and MRR. To judge the accuracy and ability of the fuzzy logic model, an average percentage error was used. The comparative evaluation of experiments and the fuzzy logic approach suggested that the obtained average errors of Ra, ESC and MRR using the fuzzy logic system were in agreement with the experimental results. Hence, the developed fuzzy logic rules can be effectively utilized to predict the ESC, Ra and MRR of PMMA and Roflufocon E CL polymers in automated optical manufacturing environments for high accuracy and a reduction of computational cost. Moreover, owing to the brittle nature of optical polymers, the Roflufocon E CL polymer requires ductile-mode machining for improved surface quality. Molecular Dynamics (MD) simulation methods are thus applied to investigate the atomistic reaction at the tool/workpiece surface to clearly study and observe conditions occurring at nanometric scale in polymer machining. This research study is particularly concerned with the comparative analysis of experiments and a MD study of the Roflufocon E optical polymer nano cutting approach to the atomistic visualization of the plastic material flow at the tool/workpiece interface during cutting. The simulated MD acting force, machine stresses, and the temperature at the cutting region were evaluated to access the accuracy of the model. Hence, the nanomachining simulations were found to have a correlation to the experimental machining results.
- Full Text:
- Date Issued: 2020
Understanding a West African recreational fishery as a complex social-ecological system – a case study of the fishery for giant African threadfin Polydactylus quadrifilis (Cuvier, 1829) in the Kwanza Estuary, Angola
- Authors: Butler, Edward C
- Date: 2020
- Subjects: Cuanza River (Angola) , Fishing -- Angola , Polynemidae , Fishes -- Angola -- Ecology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146688 , vital:38548
- Description: Despite increasing global recognition of the importance of recreational fisheries, their management largely remains poor. This is because they exhibit unique human-nature relationships and are nested within complex social-ecological systems (SESs). Recreational fisheries in the developing world have large potential for socio-economic development, but are generally underappreciated, in terms of their value and their impact, and are poorly governed. This is particularly concerning as they are highly complex and often compete for resources with dependent artisanal and subsistence fisheries. Developing world recreational fishery SESs are not well understood and present an important research gap for improved governance. The general aim of this thesis was to explore the recreational fishery targeting Polydactylus quadrifilis on the Kwanza Estuary, Angola, and provide context for how managers should approach recreational fisheries in the developing world and in Africa. To do this, the recreational fishery SES was explored using a combination of methodologies including those characteristic of traditional fisheries science, and new methods involving biology, sociology, and economics. The thesis contains an introductory chapter, a chapter describing the background, study area and study species, five data chapters and a discussion chapter. Chapter 3 aimed to investigate the reproductive style of P. quadrifilis. Results identified the species as a protandrous hermaphrodite. Evidence to suggest this included degenerating testicular tissue and the presence of early developing ovarian tissues in transitional individuals. Early-stage oocytes were commonly found in the outer area of male regions and residual late-stage spermatids and spermatozoa were found in the luminal space of ovarian regions, suggesting a process of sex change from the outside inwards. Owing to the species’ reliance on large highly fecund females for reproduction, it is likely that P. quadrifilis will be sensitive to fisheries that target larger individuals, such as trophy recreational fisheries and line fisheries within other sectors. Chapter 4 aimed to investigate alternative methods for adequately describing the growth of P. quadrifilis individuals belonging to either one of two distinct hypothetical life-history pathways: pathway I (‘changers’) – initial maturation as a primary male followed by a sex change to female; pathway II (‘non-changers’) – initial maturation as a male fish with no subsequent sex change, using von Bertalanffy Growth Functions (VBGFs). Other specific objectives included determining the size- and age-at-maturity and size- and age-at-sex-change for P. quadrifilis. Otolith aging revealed rapid growth and early maturation (L50 = 399.2 mm FL, A50 = 1.50 years) and sex change occurred over a wide size (790–1125 mm FL) and age (3–8 years) range. There was strong evidence for partial protandry in P. quadrifilis with several extremely old male fish (up to 22 years) observed in the population. When compared to the conventional model produced for the entire population, there were significant differences in the models for the ‘non-changers’ (LRT, p < 0.01) and their parameters L∞ (full model = 130.8, ‘non-changers’ = 113.3, p < 0.01), k (0.32, 0.44, p < 0.01) and t0 (0.23, 0.43, p = 0.03) in the first approach and the models (LRT, p < 0.01) and their L∞ (‘changers’ = 113.7, p < 0.01) values in the second approach. This suggests that utilising conventional modelling techniques may be inappropriate for the stock assessment and management of P. quadrifilis and, potentially, other sequentially hermaphroditic fishery species. Chapter 5 aimed to assess the sensitivity of P. quadrifilis to recreational C&R within the foreign recreational fishery using a rapid assessment approach. To do this, a number of C&R variables including fight time, air exposure, hook placement, hooking injury, total time of the stress event, river depth and angling method were measured and related to two indicators of fish health and survival – the physiological stress indicators blood glucose and blood lactate concentration and reflex action mortality predictors (RAMPs). Air exposure was identified as a major contributor to motor impairment (Cumulative Link Model: p < 0.01) and fight time was an important contributor to motor impairment via its interaction with air exposure (Cumulative Link Model: p = 0.02). Handling practices appear to be particularly important for larger individuals as fish size was positively correlated with air exposure (Pearson’s r coefficient = 0.41, p < 0.01) and fight times (0.88, p < 0.01). The findings suggest that recreational C&R may result in mortalities directly, via C&R, and indirectly, via predation, and several recommendations were made for best practice. Chapter 6 aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary. Results indicated that the recreational fishery for contributed significantly to the economy of an area that would otherwise likely receive little external input ($282 054 per four-month fishing season). However, high rates of economic leakage from the study area were identified (58.7%–92.9% of locally spent revenue) and were attributed to the sourcing of lodge supplies, services and staff outside of the local area and the repatriation of profit by foreign business owners. Capacity building within the local community is likely required to develop ‘linkages’ between the local community and the recreational fishery. Greater community involvement in the fishery is suggested to incentivise the protection of recreationally important fishery species and their associated ecosystems. Chapter 7 aimed to investigate the resource user groups involved within the SES. Results illustrated that artisanal and domestic recreational anglers are well-established and are characterised by long histories of participation. The artisanal fishery was highly valued as a source of livelihoods for the local community. Artisanal fishers were eager for involvement in the recreational sector, through the chartering of their vessels, due to the attractiveness of extra earnings. Both recreational and artisanal fishers reported recent decreases in P. quadrifilis catch and anticipated further declines. Domestic recreational anglers appeared to be highly consumptive in their use of the fishery and C&R angling was uncommon. User conflict may be problematic for future management as recreational anglers perceived the artisanal gill-net fishery to be a threat towards P. quadrifilis stocks. In conclusion, the open-access nature of the fishery was identified as the most pertinent threat to its sustainability and likely needs to be addressed. Potential solutions involve offering users the opportunity to purchase access rights (e.g. day permits), thus initiating the concept that users must pay for their use of public resources. Management should aim to protect large female fish due to their increased reproductive value and worth as trophy fish. Thus, C&R angling is likely to be an important interaction between users and the resource. However, angler behaviour will need to be manipulated to promote C&R and minimise C&R-related mortalities. Solutions include angler educational drives and interventions and the implementation of competitive C&R-only angling. Foreign recreational fisheries, although touted as potential ecotourism ventures, will only succeed in improving the lives of local people if they fully integrate the community into the operation of the fishery.
- Full Text:
- Date Issued: 2020
- Authors: Butler, Edward C
- Date: 2020
- Subjects: Cuanza River (Angola) , Fishing -- Angola , Polynemidae , Fishes -- Angola -- Ecology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146688 , vital:38548
- Description: Despite increasing global recognition of the importance of recreational fisheries, their management largely remains poor. This is because they exhibit unique human-nature relationships and are nested within complex social-ecological systems (SESs). Recreational fisheries in the developing world have large potential for socio-economic development, but are generally underappreciated, in terms of their value and their impact, and are poorly governed. This is particularly concerning as they are highly complex and often compete for resources with dependent artisanal and subsistence fisheries. Developing world recreational fishery SESs are not well understood and present an important research gap for improved governance. The general aim of this thesis was to explore the recreational fishery targeting Polydactylus quadrifilis on the Kwanza Estuary, Angola, and provide context for how managers should approach recreational fisheries in the developing world and in Africa. To do this, the recreational fishery SES was explored using a combination of methodologies including those characteristic of traditional fisheries science, and new methods involving biology, sociology, and economics. The thesis contains an introductory chapter, a chapter describing the background, study area and study species, five data chapters and a discussion chapter. Chapter 3 aimed to investigate the reproductive style of P. quadrifilis. Results identified the species as a protandrous hermaphrodite. Evidence to suggest this included degenerating testicular tissue and the presence of early developing ovarian tissues in transitional individuals. Early-stage oocytes were commonly found in the outer area of male regions and residual late-stage spermatids and spermatozoa were found in the luminal space of ovarian regions, suggesting a process of sex change from the outside inwards. Owing to the species’ reliance on large highly fecund females for reproduction, it is likely that P. quadrifilis will be sensitive to fisheries that target larger individuals, such as trophy recreational fisheries and line fisheries within other sectors. Chapter 4 aimed to investigate alternative methods for adequately describing the growth of P. quadrifilis individuals belonging to either one of two distinct hypothetical life-history pathways: pathway I (‘changers’) – initial maturation as a primary male followed by a sex change to female; pathway II (‘non-changers’) – initial maturation as a male fish with no subsequent sex change, using von Bertalanffy Growth Functions (VBGFs). Other specific objectives included determining the size- and age-at-maturity and size- and age-at-sex-change for P. quadrifilis. Otolith aging revealed rapid growth and early maturation (L50 = 399.2 mm FL, A50 = 1.50 years) and sex change occurred over a wide size (790–1125 mm FL) and age (3–8 years) range. There was strong evidence for partial protandry in P. quadrifilis with several extremely old male fish (up to 22 years) observed in the population. When compared to the conventional model produced for the entire population, there were significant differences in the models for the ‘non-changers’ (LRT, p < 0.01) and their parameters L∞ (full model = 130.8, ‘non-changers’ = 113.3, p < 0.01), k (0.32, 0.44, p < 0.01) and t0 (0.23, 0.43, p = 0.03) in the first approach and the models (LRT, p < 0.01) and their L∞ (‘changers’ = 113.7, p < 0.01) values in the second approach. This suggests that utilising conventional modelling techniques may be inappropriate for the stock assessment and management of P. quadrifilis and, potentially, other sequentially hermaphroditic fishery species. Chapter 5 aimed to assess the sensitivity of P. quadrifilis to recreational C&R within the foreign recreational fishery using a rapid assessment approach. To do this, a number of C&R variables including fight time, air exposure, hook placement, hooking injury, total time of the stress event, river depth and angling method were measured and related to two indicators of fish health and survival – the physiological stress indicators blood glucose and blood lactate concentration and reflex action mortality predictors (RAMPs). Air exposure was identified as a major contributor to motor impairment (Cumulative Link Model: p < 0.01) and fight time was an important contributor to motor impairment via its interaction with air exposure (Cumulative Link Model: p = 0.02). Handling practices appear to be particularly important for larger individuals as fish size was positively correlated with air exposure (Pearson’s r coefficient = 0.41, p < 0.01) and fight times (0.88, p < 0.01). The findings suggest that recreational C&R may result in mortalities directly, via C&R, and indirectly, via predation, and several recommendations were made for best practice. Chapter 6 aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary. Results indicated that the recreational fishery for contributed significantly to the economy of an area that would otherwise likely receive little external input ($282 054 per four-month fishing season). However, high rates of economic leakage from the study area were identified (58.7%–92.9% of locally spent revenue) and were attributed to the sourcing of lodge supplies, services and staff outside of the local area and the repatriation of profit by foreign business owners. Capacity building within the local community is likely required to develop ‘linkages’ between the local community and the recreational fishery. Greater community involvement in the fishery is suggested to incentivise the protection of recreationally important fishery species and their associated ecosystems. Chapter 7 aimed to investigate the resource user groups involved within the SES. Results illustrated that artisanal and domestic recreational anglers are well-established and are characterised by long histories of participation. The artisanal fishery was highly valued as a source of livelihoods for the local community. Artisanal fishers were eager for involvement in the recreational sector, through the chartering of their vessels, due to the attractiveness of extra earnings. Both recreational and artisanal fishers reported recent decreases in P. quadrifilis catch and anticipated further declines. Domestic recreational anglers appeared to be highly consumptive in their use of the fishery and C&R angling was uncommon. User conflict may be problematic for future management as recreational anglers perceived the artisanal gill-net fishery to be a threat towards P. quadrifilis stocks. In conclusion, the open-access nature of the fishery was identified as the most pertinent threat to its sustainability and likely needs to be addressed. Potential solutions involve offering users the opportunity to purchase access rights (e.g. day permits), thus initiating the concept that users must pay for their use of public resources. Management should aim to protect large female fish due to their increased reproductive value and worth as trophy fish. Thus, C&R angling is likely to be an important interaction between users and the resource. However, angler behaviour will need to be manipulated to promote C&R and minimise C&R-related mortalities. Solutions include angler educational drives and interventions and the implementation of competitive C&R-only angling. Foreign recreational fisheries, although touted as potential ecotourism ventures, will only succeed in improving the lives of local people if they fully integrate the community into the operation of the fishery.
- Full Text:
- Date Issued: 2020
Understanding biotic interactions in invaded pond communities in the Sundays River irrigation network, South Africa
- Authors: Mofu, Lubabalo
- Date: 2020
- Subjects: Mozambique tilapia -- South Africa -- Sundays River (Eastern Cape) , Western mosquitofish -- South Africa -- Sundays River (Eastern Cape) , Gobiidae -- South Africa -- Sundays River (Eastern Cape) , Clupeidae -- South Africa -- Sundays River (Eastern Cape) , Reservoirs -- South Africa -- Sundays River (Eastern Cape) , Zooplankton -- South Africa -- Sundays River (Eastern Cape) , Freshwater ecology -- South Africa -- Sundays River (Eastern Cape) , Biotic communities -- South Africa -- Sundays River (Eastern Cape) , Fishes -- Effect of temperature on -- South Africa -- Sundays River (Eastern Cape) , Stable isotopes , Relative Impact Potential
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167089 , vital:41436
- Description: The Sundays River valley irrigation ponds provide a unique opportunity to investigate biotic interactions within a biological invasions context, as they contain both native and non-native fish species. This study focusses on two native species (Glossogobius callidus and Gilchristella aestuaria) and two non-native species (Oreochromis mossambicus and Gambusia affinis). The ecology of the ponds was driven by physico-chemical variables, mainly temperature, but the interactions between fishes were a complex interplay between temperature, pond community ecology and food web structure. Seasonal changes in temperature and subsequent fluctuations in water levels resulted in changes in zooplankton community. Chlorophyll-a, temperature, G. callidus and G. affinis were the drivers of the seasonal changes in macroinvertebrate composition. Stable isotope analysis identified substantial ontogenetic dietary shifts in all species, corresponding to changes in body size. Stable isotope analysis revealed that the niche space occupied by G. affinis was broad and overlapped with that of the other three focal species. Stable isotope metrics showed that G. affinis and O. mossambicus utilised a wide range of resources compared to G. callidus and G. aestuaria. Stomach content analysis showed that G. callidus, O. mossambicus and G. affinis fed predominantly on benthic resources, while G. aestuaria fed mainly plankton resources. Functional response experiments revealed that G. callidus and G. affinis both displayed Type II functional responses. In single fish trials, G. affinis had significantly higher functional responses than G. callidus. In heterospecific G. callidus-G. affinis combinations the functional response of G. callidus was reduced by the presence of G. affinis, whereas, this combination greatly enhanced G. affinis functional response magnitudes. The functional response of G. callidus, O. mossambicus and G. affinis under two temperature treatments along with fish abundance data was used to determine temporal differences in the ecological impacts of each fish species between seasons. The relative impact potential of O. mossambicus was consistently higher than that of G. callidus and G. affinis. This study demonstrates how seasonal temperature fluctuations affect the relative impact capacities of introduced species. Overall, this thesis showed that high temperature along with life-history traits contributes to the biotic interactions between native and non-native species in novel environments.
- Full Text:
- Date Issued: 2020
- Authors: Mofu, Lubabalo
- Date: 2020
- Subjects: Mozambique tilapia -- South Africa -- Sundays River (Eastern Cape) , Western mosquitofish -- South Africa -- Sundays River (Eastern Cape) , Gobiidae -- South Africa -- Sundays River (Eastern Cape) , Clupeidae -- South Africa -- Sundays River (Eastern Cape) , Reservoirs -- South Africa -- Sundays River (Eastern Cape) , Zooplankton -- South Africa -- Sundays River (Eastern Cape) , Freshwater ecology -- South Africa -- Sundays River (Eastern Cape) , Biotic communities -- South Africa -- Sundays River (Eastern Cape) , Fishes -- Effect of temperature on -- South Africa -- Sundays River (Eastern Cape) , Stable isotopes , Relative Impact Potential
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167089 , vital:41436
- Description: The Sundays River valley irrigation ponds provide a unique opportunity to investigate biotic interactions within a biological invasions context, as they contain both native and non-native fish species. This study focusses on two native species (Glossogobius callidus and Gilchristella aestuaria) and two non-native species (Oreochromis mossambicus and Gambusia affinis). The ecology of the ponds was driven by physico-chemical variables, mainly temperature, but the interactions between fishes were a complex interplay between temperature, pond community ecology and food web structure. Seasonal changes in temperature and subsequent fluctuations in water levels resulted in changes in zooplankton community. Chlorophyll-a, temperature, G. callidus and G. affinis were the drivers of the seasonal changes in macroinvertebrate composition. Stable isotope analysis identified substantial ontogenetic dietary shifts in all species, corresponding to changes in body size. Stable isotope analysis revealed that the niche space occupied by G. affinis was broad and overlapped with that of the other three focal species. Stable isotope metrics showed that G. affinis and O. mossambicus utilised a wide range of resources compared to G. callidus and G. aestuaria. Stomach content analysis showed that G. callidus, O. mossambicus and G. affinis fed predominantly on benthic resources, while G. aestuaria fed mainly plankton resources. Functional response experiments revealed that G. callidus and G. affinis both displayed Type II functional responses. In single fish trials, G. affinis had significantly higher functional responses than G. callidus. In heterospecific G. callidus-G. affinis combinations the functional response of G. callidus was reduced by the presence of G. affinis, whereas, this combination greatly enhanced G. affinis functional response magnitudes. The functional response of G. callidus, O. mossambicus and G. affinis under two temperature treatments along with fish abundance data was used to determine temporal differences in the ecological impacts of each fish species between seasons. The relative impact potential of O. mossambicus was consistently higher than that of G. callidus and G. affinis. This study demonstrates how seasonal temperature fluctuations affect the relative impact capacities of introduced species. Overall, this thesis showed that high temperature along with life-history traits contributes to the biotic interactions between native and non-native species in novel environments.
- Full Text:
- Date Issued: 2020
Understanding climate change and rural livelihoods in Zimbabwe: adaptation by communal farmers in Ngundu, Chivi District
- Authors: Nciizah, Elinah
- Date: 2020
- Subjects: Agriculture -- Zimbabwe , Agriculture -- Climatic factors -- Chivi District (Zimbabwe) , Chivi District (Zimbabwe) -- Rural conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/118765 , vital:34666
- Description: Climate change and variability is a global phenomenon which has deeply localised patterns, dynamics and effects. Amongst those people who are particularly vulnerable to climate change effects are small-scale farmers who are dependent in large part on rain-fed agriculture in pursuing their livelihoods. This is true of small-scale farmers in contemporary Zimbabwe and, more specifically, farmers in communal areas. At the same time, at international and national levels, there are attempts currently to minimise the effects of, and to adapt to, climate change. However, adaptation measures also exist at local levels amongst small-scale farmers, such as communal farmers in Zimbabwe. In this context, as its main objective, this thesis examines climate change and small-scale farmer livelihood adaptation to climate change with specific reference to communal farmers in Chivi District in Zimbabwe and, in particular, in Ward 25 which is popularly known as Ngundu. In pursuing this main objective, a number of subsidiary objectives are addressed, including a focus on the established livelihoods of Ngundu farmers, the perceptions and concerns of Ngundu farmers about climate change, the coping and adaptation measures of Ngundu farmers, and the enablements and constraints which affect attempts by Ngundu farmers to adopt such measures. The fieldwork for the thesis involved a diverse array of research methods, such as a questionnaire survey, life-history interviews, key informant interviews, focus group discussions and transect walks. In terms of theoretical framing, the thesis makes use of both middle-level theory (the Sustainable Livelihoods Framework) and macro-theory in the form of the sociological work of Margaret Archer. Combined, these two theories allow for a focus on both structure and agency when seeking to understand livelihood adaptations to climate change by communal farmers in Ngundu. The thesis concludes that there are massive constraints inhibiting adaptation measures by Ngundu farmers, but that this should not distract from the deep, often historically-embedded, concerns of Ngundu farmers about climate change and the multiple ways in which they express agency in and through adaptation and coping activities. It also highlights the need for more specifically sociological investigations of climate change and small-scale farmer adaptation, as well as the need for localised studies which are able to identify and analyse the specificities of adaptation.
- Full Text:
- Date Issued: 2020
- Authors: Nciizah, Elinah
- Date: 2020
- Subjects: Agriculture -- Zimbabwe , Agriculture -- Climatic factors -- Chivi District (Zimbabwe) , Chivi District (Zimbabwe) -- Rural conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/118765 , vital:34666
- Description: Climate change and variability is a global phenomenon which has deeply localised patterns, dynamics and effects. Amongst those people who are particularly vulnerable to climate change effects are small-scale farmers who are dependent in large part on rain-fed agriculture in pursuing their livelihoods. This is true of small-scale farmers in contemporary Zimbabwe and, more specifically, farmers in communal areas. At the same time, at international and national levels, there are attempts currently to minimise the effects of, and to adapt to, climate change. However, adaptation measures also exist at local levels amongst small-scale farmers, such as communal farmers in Zimbabwe. In this context, as its main objective, this thesis examines climate change and small-scale farmer livelihood adaptation to climate change with specific reference to communal farmers in Chivi District in Zimbabwe and, in particular, in Ward 25 which is popularly known as Ngundu. In pursuing this main objective, a number of subsidiary objectives are addressed, including a focus on the established livelihoods of Ngundu farmers, the perceptions and concerns of Ngundu farmers about climate change, the coping and adaptation measures of Ngundu farmers, and the enablements and constraints which affect attempts by Ngundu farmers to adopt such measures. The fieldwork for the thesis involved a diverse array of research methods, such as a questionnaire survey, life-history interviews, key informant interviews, focus group discussions and transect walks. In terms of theoretical framing, the thesis makes use of both middle-level theory (the Sustainable Livelihoods Framework) and macro-theory in the form of the sociological work of Margaret Archer. Combined, these two theories allow for a focus on both structure and agency when seeking to understand livelihood adaptations to climate change by communal farmers in Ngundu. The thesis concludes that there are massive constraints inhibiting adaptation measures by Ngundu farmers, but that this should not distract from the deep, often historically-embedded, concerns of Ngundu farmers about climate change and the multiple ways in which they express agency in and through adaptation and coping activities. It also highlights the need for more specifically sociological investigations of climate change and small-scale farmer adaptation, as well as the need for localised studies which are able to identify and analyse the specificities of adaptation.
- Full Text:
- Date Issued: 2020
Uphicotho lweencwadi zabantwana ezikhethiweyo eziguqulelwe esiXhoseni
- Authors: Madolo, Yolisa
- Date: 2020
- Subjects: Children's literature, South African , Xhosa fiction -- Juvenile literature , Xhosa language -- Juvenile literature , Translating and interpreting in literature , Xhosa literature , Xhosa language -- Translating
- Language: Xhosa
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150515 , vital:38981
- Description: Appraisal of African languages’ children’s literature and its translation seems to be developing at a slow pace. This literary genre seems to be the last on the literary critics’ list. As a result, children’s literature translators seem to do as they please, with no fear that there is someone to critique the work. Translation for children is more than just literary translation, because it is meant for a special audience, whose language skills are still developing. The translator, therefore, needs to be someone dedicated in target language development. This translation needs a translator with a deep knowledge of both the source and target languages and their cultures. This will result in a translation that is readable and acceptable in the target language. The aim of this study was to critically analyse 20 selected isiXhosa translated stories, looking at how they have been translated in order to sound original in the target language. A sample of five stories were taken and analysed looking at their macrostructure. The findings of the analysis were that the isiXhosa stories resembled the English ones. Even the equivalence of the translated versions showed that the translation transferred the message in the source texts. However there were challenges as indicated. The study was done using Skopos theory, which advocates for the translator to always keep their audience in mind. It suggests that the translator should always strive for a translation that is acceptable to the target language. Various strategies can be used by the translator to fulfil this. Some of the strategies found to have been used in the translations are adaptation through omission, addition, addition of target culture specific terms, and changing sentence mode. Generally, the source language message seems to have been successfully transferred to the target language. However, errors in some stories were a cause for concern, as they could deter the target reader’s interest in the stories. Such errors are spelling mistakes, word division errors, incorrect concord use, etc. These errors are a matter of concern in literature, more especially children’s literature where children are still developing their reading skills.
- Full Text:
- Date Issued: 2020
- Authors: Madolo, Yolisa
- Date: 2020
- Subjects: Children's literature, South African , Xhosa fiction -- Juvenile literature , Xhosa language -- Juvenile literature , Translating and interpreting in literature , Xhosa literature , Xhosa language -- Translating
- Language: Xhosa
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150515 , vital:38981
- Description: Appraisal of African languages’ children’s literature and its translation seems to be developing at a slow pace. This literary genre seems to be the last on the literary critics’ list. As a result, children’s literature translators seem to do as they please, with no fear that there is someone to critique the work. Translation for children is more than just literary translation, because it is meant for a special audience, whose language skills are still developing. The translator, therefore, needs to be someone dedicated in target language development. This translation needs a translator with a deep knowledge of both the source and target languages and their cultures. This will result in a translation that is readable and acceptable in the target language. The aim of this study was to critically analyse 20 selected isiXhosa translated stories, looking at how they have been translated in order to sound original in the target language. A sample of five stories were taken and analysed looking at their macrostructure. The findings of the analysis were that the isiXhosa stories resembled the English ones. Even the equivalence of the translated versions showed that the translation transferred the message in the source texts. However there were challenges as indicated. The study was done using Skopos theory, which advocates for the translator to always keep their audience in mind. It suggests that the translator should always strive for a translation that is acceptable to the target language. Various strategies can be used by the translator to fulfil this. Some of the strategies found to have been used in the translations are adaptation through omission, addition, addition of target culture specific terms, and changing sentence mode. Generally, the source language message seems to have been successfully transferred to the target language. However, errors in some stories were a cause for concern, as they could deter the target reader’s interest in the stories. Such errors are spelling mistakes, word division errors, incorrect concord use, etc. These errors are a matter of concern in literature, more especially children’s literature where children are still developing their reading skills.
- Full Text:
- Date Issued: 2020
Urbanisation, foraging and household food security in urban South Africa
- Authors: Garekae, Hesekia
- Date: 2020
- Subjects: Food sovereignty -- South Africa , Food security -- South Africa , Urban density -- South Africa , Urban agriculture -- Law and legislation -- South Africa , Sustainable urban development -- South Africa , Urban ecology (Sociology) -- South Africa , Nutrition surveys -- South Africa -- Potchefstroom , Nutrition surveys -- South Africa -- Thabazimbi , Wild plants, Edible -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167054 , vital:41433
- Description: Over the past several decades, the world’s population has been rapidly urbanising, which has resulted in a marked shift of global population from rural to urban areas. About half of the global population now reside in urban areas and is projected to increase to two-thirds by the year 2050. However, the majority of the future urban population growth is projected to be largely concentrated in Asia and sub-Saharan Africa. Despite the economic prospects normally synonymous with urbanisation, the current speed and scale of urban transformation comes with formidable challenges to contemporary urban society in these two continents. Urbanisation may presents social, economic, health and environmental challenges in urban areas, not least being a shift of the locus of food insecurity from rural to urban areas, leading to poor dietary diversity among many urban dwellers. Similarly, urbanisation alters key ecosystem services and drives habitat alteration and fragmentation, biodiversity loss, proliferation of non-native species and changes on species diversity and richness. The aforementioned changes can result in a deterioration of living conditions and decline on the quality of life for the urban dwellers. However, on the other hand, urban green infrastructure is posed as vital tool in promoting liveable cities and enhancing livelihood resilience. Against this backdrop, this study portrays wild plants, a component of urban green infrastructure, as a key resource in promoting food security and dietary diversity, thereby promoting livelihood resilience and reduced vulnerability, especially of the urban poor. Framed under the ‘right to the city’ approach, this study examined urban foraging practices and their potential contribution to dietary diversity and how they are shaped by and respond to urbanisation in two medium-sized South African towns. The study was conducted in the towns of Potchefstroom and Thabazimbi, South Africa. An explanatory sequential mixed method design was employed for data collection. Multi-stage sampling was employed in selecting the study participants. Firstly, the study towns were stratified into four socio-economic zones: informal, reconstruction and development programme, township and affluent. These zones resemble high density (informal, reconstruction and development programme), medium density (township) and low density (affluent) areas. Then, a total of 374 households were randomly sampled across the socio-economic zones for the main survey (Chapter 3 and 5). A subset of this sample, i.e. 72 participants was considered for dietary recalls, alongside with a random sample of 65 non-foragers (Chapter 4). An inventory of plant species available in a given foraging space was conducted from a total of 136 plots spread across different urban spaces (Chapter 2). Semi-structured interviews were conducted with a total of 81 participants (sub population of the main survey) for elucidating data on urban dynamics (Chapter 6). Lastly, complementary in-depth interviews with 46 participants were conducted. The findings showed that different urban spaces were constituted by diverse vegetation, with 262 distinct plant species encountered across the spaces. The majority (60.7%) were indigenous to South Africa. Species composition and diversity varied with space type, being significantly high in protected areas as compared to the other space types. About half (53%) of the identified plant species had at least one documented use, with medicine, food and firewood being modal, in order of frequency. Species composition and diversity differed between forageable and non-forageable species, being significantly high for forageable species. Urban foraging was widespread, about 68% of the respondents reported foraging. Foraging provided food, fuel energy, medicine, and cultural affirmation, among others. Despite the high prevalence rate of foraging, the study did not find any meaningful contribution of wild foods to overall diets. Nonetheless, wild foods demonstrated a substantial contribution in diversifying diets within particular food groups consumed such as vegetables, thus emerging essential in mitigating monotonous urban diets, particularly of the urban poor. Besides, the prevalence of foraging differed significantly between and within towns, being high for Thabazimbi (54.7%) and residents in the outskirts of town (86.2%) than Potchefstroom (45.3%) and residents in the inner part of town (33.3%). Participation in foraging was primarily a function of childhood (91.8%) exposure and experience with foraging, positive perceptions (79%) towards practice, resident in the outskirts of town (86.2%) and low household income (49.2%). The findings indicated that foraging was driven by multifaceted motivations, with culture (91.8%), health (88.7%), livelihoods needs (75.0%) and leisure (73.8%) being the most common. Vacant spaces (54.7%), riparian areas (30%), and domestic gardens (17.9%) were the most preferred foraging spaces, albeit with differences within towns. Similarly, the mean frequency of access varied with foraging spaces, being slightly high for vacant spaces than riparian areas and domestic gardens. The majority of the respondents were unaware of both formal and informal regulations managing urban landscapes, with those acknowledging some awareness falling short of articulating on the specificities of the regulations. Besides, the findings showed that foraging practice was threatened by urban transformation. Foragers perceived that the practice has changed over time, in terms of spaces, participants and regulations. There was a decreasing trend on the number and size of foraging spaces as well as shifting demographic trends of foragers. Moreover, urban transformation brought about a new set of regulations used for managing certain spaces within the urban landscape. However, some regulations prohibited or restricted access and rights to certain spaces for foraging. Hence, this prompted foragers to devise adaptation strategies to cope with the said changing dynamics. Exploring new foraging sites within and outside forager’s neighbourhoods and negotiating access entry were the most frequently mentioned adaptation strategies. This study contributes to the emerging body of knowledge on urban foraging, which has being seldom understood in the Global South.
- Full Text:
- Date Issued: 2020
- Authors: Garekae, Hesekia
- Date: 2020
- Subjects: Food sovereignty -- South Africa , Food security -- South Africa , Urban density -- South Africa , Urban agriculture -- Law and legislation -- South Africa , Sustainable urban development -- South Africa , Urban ecology (Sociology) -- South Africa , Nutrition surveys -- South Africa -- Potchefstroom , Nutrition surveys -- South Africa -- Thabazimbi , Wild plants, Edible -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167054 , vital:41433
- Description: Over the past several decades, the world’s population has been rapidly urbanising, which has resulted in a marked shift of global population from rural to urban areas. About half of the global population now reside in urban areas and is projected to increase to two-thirds by the year 2050. However, the majority of the future urban population growth is projected to be largely concentrated in Asia and sub-Saharan Africa. Despite the economic prospects normally synonymous with urbanisation, the current speed and scale of urban transformation comes with formidable challenges to contemporary urban society in these two continents. Urbanisation may presents social, economic, health and environmental challenges in urban areas, not least being a shift of the locus of food insecurity from rural to urban areas, leading to poor dietary diversity among many urban dwellers. Similarly, urbanisation alters key ecosystem services and drives habitat alteration and fragmentation, biodiversity loss, proliferation of non-native species and changes on species diversity and richness. The aforementioned changes can result in a deterioration of living conditions and decline on the quality of life for the urban dwellers. However, on the other hand, urban green infrastructure is posed as vital tool in promoting liveable cities and enhancing livelihood resilience. Against this backdrop, this study portrays wild plants, a component of urban green infrastructure, as a key resource in promoting food security and dietary diversity, thereby promoting livelihood resilience and reduced vulnerability, especially of the urban poor. Framed under the ‘right to the city’ approach, this study examined urban foraging practices and their potential contribution to dietary diversity and how they are shaped by and respond to urbanisation in two medium-sized South African towns. The study was conducted in the towns of Potchefstroom and Thabazimbi, South Africa. An explanatory sequential mixed method design was employed for data collection. Multi-stage sampling was employed in selecting the study participants. Firstly, the study towns were stratified into four socio-economic zones: informal, reconstruction and development programme, township and affluent. These zones resemble high density (informal, reconstruction and development programme), medium density (township) and low density (affluent) areas. Then, a total of 374 households were randomly sampled across the socio-economic zones for the main survey (Chapter 3 and 5). A subset of this sample, i.e. 72 participants was considered for dietary recalls, alongside with a random sample of 65 non-foragers (Chapter 4). An inventory of plant species available in a given foraging space was conducted from a total of 136 plots spread across different urban spaces (Chapter 2). Semi-structured interviews were conducted with a total of 81 participants (sub population of the main survey) for elucidating data on urban dynamics (Chapter 6). Lastly, complementary in-depth interviews with 46 participants were conducted. The findings showed that different urban spaces were constituted by diverse vegetation, with 262 distinct plant species encountered across the spaces. The majority (60.7%) were indigenous to South Africa. Species composition and diversity varied with space type, being significantly high in protected areas as compared to the other space types. About half (53%) of the identified plant species had at least one documented use, with medicine, food and firewood being modal, in order of frequency. Species composition and diversity differed between forageable and non-forageable species, being significantly high for forageable species. Urban foraging was widespread, about 68% of the respondents reported foraging. Foraging provided food, fuel energy, medicine, and cultural affirmation, among others. Despite the high prevalence rate of foraging, the study did not find any meaningful contribution of wild foods to overall diets. Nonetheless, wild foods demonstrated a substantial contribution in diversifying diets within particular food groups consumed such as vegetables, thus emerging essential in mitigating monotonous urban diets, particularly of the urban poor. Besides, the prevalence of foraging differed significantly between and within towns, being high for Thabazimbi (54.7%) and residents in the outskirts of town (86.2%) than Potchefstroom (45.3%) and residents in the inner part of town (33.3%). Participation in foraging was primarily a function of childhood (91.8%) exposure and experience with foraging, positive perceptions (79%) towards practice, resident in the outskirts of town (86.2%) and low household income (49.2%). The findings indicated that foraging was driven by multifaceted motivations, with culture (91.8%), health (88.7%), livelihoods needs (75.0%) and leisure (73.8%) being the most common. Vacant spaces (54.7%), riparian areas (30%), and domestic gardens (17.9%) were the most preferred foraging spaces, albeit with differences within towns. Similarly, the mean frequency of access varied with foraging spaces, being slightly high for vacant spaces than riparian areas and domestic gardens. The majority of the respondents were unaware of both formal and informal regulations managing urban landscapes, with those acknowledging some awareness falling short of articulating on the specificities of the regulations. Besides, the findings showed that foraging practice was threatened by urban transformation. Foragers perceived that the practice has changed over time, in terms of spaces, participants and regulations. There was a decreasing trend on the number and size of foraging spaces as well as shifting demographic trends of foragers. Moreover, urban transformation brought about a new set of regulations used for managing certain spaces within the urban landscape. However, some regulations prohibited or restricted access and rights to certain spaces for foraging. Hence, this prompted foragers to devise adaptation strategies to cope with the said changing dynamics. Exploring new foraging sites within and outside forager’s neighbourhoods and negotiating access entry were the most frequently mentioned adaptation strategies. This study contributes to the emerging body of knowledge on urban foraging, which has being seldom understood in the Global South.
- Full Text:
- Date Issued: 2020
Walking at the intersection of Seamon’s place ballet and Relph’s insideness: understanding how students experience the university as a place through their everyday habitual walking
- Mtolo, Siyathokoza Monwabisi
- Authors: Mtolo, Siyathokoza Monwabisi
- Date: 2020
- Subjects: Seamon, David , Relph, EC , College students -- South Africa -- Makhanda -- Attitudes , Walking -- Sociological aspects , College students -- South Africa -- Makhanda -- Political activity , Rhodes University -- Students -- Attitudes , Student movements -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162901 , vital:40995
- Description: Walking as a way to experience a place is a relatively understudied area of phenomenological study. Furthermore, globally (the world) and locally (South Africa) the study of the experience of tertiary education institutions as walked environments is minimal (see Puig-Ribera et al., 2008; Speck et al., 2010; Mtolo, 2017). However, the events of the South African #MustFall moment – especially the #RhodesMustFall part of the moment and how it began with the desecration of a statue that was walked past and found to be a misplaced artefact in a society that is in postcolonial/post-Apartheid times and space – highlighted the pressing need to study the experience of the university as a place through which habitual walking takes the student through moments of movement, rest, and encounter that are a highly consequential way in which placeness is experienced. This study is a way to document how students at Rhodes University experience the university’s placeness quality, through habitual walking, in an example of the way in which a place is experienced through moments of movement, rest, and encounter. For this study in-depth mobile interviews were conducted with 12 student participants from Rhodes University. The interviews were video-recorded as the participants talked while traversing through habitually walked areas of the campus that are the meaning-infused spaces which make up the Rhodes University that they traverse through on a daily basis. The dissertation found that in the experience of Rhodes University, through habitually walking its placeness, people experience moments of movement, rest, and encounter that are highly targeted and personalised. The experience of the Rhodes University campus is an experience of people and the built-up and decorated environment along similar lines. People bring to the experience of their walked space past experiences which inform consequentially how any space that is walked is experienced. People further employ strategies to ensure that the experience of walking a space is more to their desired quality as an experience, which ends up being meaningful and most likely to affect future instances of walking through meaning-infusing and meaning-infused space. Ultimately, the habitual walking of Rhodes University consequentially informs the relationship between students and Rhodes University’s placeness, as the walking is a way of learning how to be within a placeness that is engaged through alternating moments of movement, rest, and encounter that incrementally ‘open’ for experience Rhodes University in such a targeted manner that every student eventually has their personal and customised Rhodes University by virtue of it being just those sites and situations which have been engaged through habitual walking.
- Full Text:
- Date Issued: 2020
- Authors: Mtolo, Siyathokoza Monwabisi
- Date: 2020
- Subjects: Seamon, David , Relph, EC , College students -- South Africa -- Makhanda -- Attitudes , Walking -- Sociological aspects , College students -- South Africa -- Makhanda -- Political activity , Rhodes University -- Students -- Attitudes , Student movements -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162901 , vital:40995
- Description: Walking as a way to experience a place is a relatively understudied area of phenomenological study. Furthermore, globally (the world) and locally (South Africa) the study of the experience of tertiary education institutions as walked environments is minimal (see Puig-Ribera et al., 2008; Speck et al., 2010; Mtolo, 2017). However, the events of the South African #MustFall moment – especially the #RhodesMustFall part of the moment and how it began with the desecration of a statue that was walked past and found to be a misplaced artefact in a society that is in postcolonial/post-Apartheid times and space – highlighted the pressing need to study the experience of the university as a place through which habitual walking takes the student through moments of movement, rest, and encounter that are a highly consequential way in which placeness is experienced. This study is a way to document how students at Rhodes University experience the university’s placeness quality, through habitual walking, in an example of the way in which a place is experienced through moments of movement, rest, and encounter. For this study in-depth mobile interviews were conducted with 12 student participants from Rhodes University. The interviews were video-recorded as the participants talked while traversing through habitually walked areas of the campus that are the meaning-infused spaces which make up the Rhodes University that they traverse through on a daily basis. The dissertation found that in the experience of Rhodes University, through habitually walking its placeness, people experience moments of movement, rest, and encounter that are highly targeted and personalised. The experience of the Rhodes University campus is an experience of people and the built-up and decorated environment along similar lines. People bring to the experience of their walked space past experiences which inform consequentially how any space that is walked is experienced. People further employ strategies to ensure that the experience of walking a space is more to their desired quality as an experience, which ends up being meaningful and most likely to affect future instances of walking through meaning-infusing and meaning-infused space. Ultimately, the habitual walking of Rhodes University consequentially informs the relationship between students and Rhodes University’s placeness, as the walking is a way of learning how to be within a placeness that is engaged through alternating moments of movement, rest, and encounter that incrementally ‘open’ for experience Rhodes University in such a targeted manner that every student eventually has their personal and customised Rhodes University by virtue of it being just those sites and situations which have been engaged through habitual walking.
- Full Text:
- Date Issued: 2020