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Azadipyrromethenes for applications in photodynamic antimicrobial chemotherapy, photodynamic therapy and optical limiting
- Authors: Dubazana, Nadine
- Date: 2020
- Subjects: Dyes and dyeing -- Chemistry , Photochemotherapy , Cancer -- Photochemotherapy , Anti-infective agents , Staphylococcus aureus , Nonlinear optics , Azadipyrromethenes , BODIPY
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166150 , vital:41333
- Description: Azadipyrromethenes, azaBODIPYs and zinc azadipyrromethene complexes were prepared and characterised to examine the effect on their photophysical properties of incorporating phenyl groups at the 1,3,5,7-positions with electron-donating and withdrawing groups at the para-positions. To enhance their ability to generate singlet oxygen, appropriate structural modifications were made through the addition of a Zn(II) ion or halogenation at the 2,6 positions. In vitro photodynamic therapy (PDT) studies targeting MCF-7 human breast cancer cells were carried out. To evaluate and understand the effectiveness of the dyes as photosensitisers, cellular uptake, phototoxicity and the half-maximal inhibitory concentration (IC50) values were analysed. Photodynamic antimicrobial chemotherapy (PACT) studies were also carried out to study the effectiveness of the dyes against Staphylococcus aureus (S. aureus). Dyes with donor-π-acceptor (D-π-A) properties were synthesised and tested against the second harmonic of the Nd:YAG laser in optical limiting (OL) studies. The second-order hyperpolarisability, third-order susceptibility and nonlinear absorption coefficient values were determined. The results suggest that 1,3,5,7-azaBODIPY dyes may be less suitable for use in this context than analogous D-π-A 3,5-distyrylBODIPY dyes. Molecular modelling was carried out to identify the structure-property relationships of the synthesised dyes by analysing trends in the energies of the frontier molecular orbitals (MOs) and spectroscopic properties.
- Full Text:
- Authors: Dubazana, Nadine
- Date: 2020
- Subjects: Dyes and dyeing -- Chemistry , Photochemotherapy , Cancer -- Photochemotherapy , Anti-infective agents , Staphylococcus aureus , Nonlinear optics , Azadipyrromethenes , BODIPY
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166150 , vital:41333
- Description: Azadipyrromethenes, azaBODIPYs and zinc azadipyrromethene complexes were prepared and characterised to examine the effect on their photophysical properties of incorporating phenyl groups at the 1,3,5,7-positions with electron-donating and withdrawing groups at the para-positions. To enhance their ability to generate singlet oxygen, appropriate structural modifications were made through the addition of a Zn(II) ion or halogenation at the 2,6 positions. In vitro photodynamic therapy (PDT) studies targeting MCF-7 human breast cancer cells were carried out. To evaluate and understand the effectiveness of the dyes as photosensitisers, cellular uptake, phototoxicity and the half-maximal inhibitory concentration (IC50) values were analysed. Photodynamic antimicrobial chemotherapy (PACT) studies were also carried out to study the effectiveness of the dyes against Staphylococcus aureus (S. aureus). Dyes with donor-π-acceptor (D-π-A) properties were synthesised and tested against the second harmonic of the Nd:YAG laser in optical limiting (OL) studies. The second-order hyperpolarisability, third-order susceptibility and nonlinear absorption coefficient values were determined. The results suggest that 1,3,5,7-azaBODIPY dyes may be less suitable for use in this context than analogous D-π-A 3,5-distyrylBODIPY dyes. Molecular modelling was carried out to identify the structure-property relationships of the synthesised dyes by analysing trends in the energies of the frontier molecular orbitals (MOs) and spectroscopic properties.
- Full Text:
Bacterial degradation of coal discard and geologically weathered coal:
- Olawale, Jacob Taiwo, Edeki, Oghenekume Gerald, Cowan, Ashton Keith
- Authors: Olawale, Jacob Taiwo , Edeki, Oghenekume Gerald , Cowan, Ashton Keith
- Date: 2020
- Language: English
- Type: text , article
- Identifier: vital:40097 , https://doi.org/10.1007/s40789-020-00306-3
- Description: The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India.
- Full Text:
- Authors: Olawale, Jacob Taiwo , Edeki, Oghenekume Gerald , Cowan, Ashton Keith
- Date: 2020
- Language: English
- Type: text , article
- Identifier: vital:40097 , https://doi.org/10.1007/s40789-020-00306-3
- Description: The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India.
- Full Text:
Bail applications in Nigeria and South Africa
- Authors: Babalola, Abdulateef Taiwo
- Date: 2020
- Subjects: Bail -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/47325 , vital:39847
- Description: Between the point of arrest and conviction, an accused person has a right to be released on bail based on his or her Constitutional right to liberty as well as the right to be presumed innocent. To grant bail to an accused person serves as a form of contract of insurance or a guarantee that if the accused person is released pending the determination of the case against him, he will not frustrate the course of justice and will appear at a later date to face trial. The essence of bail is to allow the accused person enjoy his right to liberty pending the determination of the criminal charge if the interest of justice will permit for his or her release. This study aims at comparing bail proceedings in both the Nigerian and South African criminal justice systems. The constitutions of both jurisdictions make provision for bail, as well as the Administration of Criminal Justice Act applicable in Nigeria and the Criminal Procedure Act which is applicable in South Africa. By comparing both jurisdictions, the similarities and differences that exist between both systems will become evident, which makes them unique and distinct of each other. During the course of this study, it will be discovered that the Nigerian bail procedure do not meet up to international standards in protecting the right to personal liberty of accused persons. It is believed that the recommendations that will be suggested in this study will improve the Nigerian bail procedure and make it more effective and efficient.
- Full Text:
- Authors: Babalola, Abdulateef Taiwo
- Date: 2020
- Subjects: Bail -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/47325 , vital:39847
- Description: Between the point of arrest and conviction, an accused person has a right to be released on bail based on his or her Constitutional right to liberty as well as the right to be presumed innocent. To grant bail to an accused person serves as a form of contract of insurance or a guarantee that if the accused person is released pending the determination of the case against him, he will not frustrate the course of justice and will appear at a later date to face trial. The essence of bail is to allow the accused person enjoy his right to liberty pending the determination of the criminal charge if the interest of justice will permit for his or her release. This study aims at comparing bail proceedings in both the Nigerian and South African criminal justice systems. The constitutions of both jurisdictions make provision for bail, as well as the Administration of Criminal Justice Act applicable in Nigeria and the Criminal Procedure Act which is applicable in South Africa. By comparing both jurisdictions, the similarities and differences that exist between both systems will become evident, which makes them unique and distinct of each other. During the course of this study, it will be discovered that the Nigerian bail procedure do not meet up to international standards in protecting the right to personal liberty of accused persons. It is believed that the recommendations that will be suggested in this study will improve the Nigerian bail procedure and make it more effective and efficient.
- Full Text:
Barriers to, and enablers of urban tree planting in low-cost housing areas: lessons from participatory learning processes in South Africa
- Authors: Gwedla, Nanamhla
- Date: 2020
- Subjects: Urban ecology (Sociology) -- South Africa -- Eastern Cape , Tree planting -- South Africa -- Eastern Cape , Trees in cities -- South Africa -- Eastern Cape , Urban forestry -- Law and legislation -- South Africa -- Eastern Cape , Low-income housing -- South Africa -- Eastern Cape , Cultural Historical Activity Theory (CHAT)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167065 , vital:41434
- Description: The recent pronouncement of low-cost housing areas as sustainable human settlements came with an expectation for their development in line with Sustainable Development Goal (SDG) 11. Unfortunately, the historical legacy and various socio-economic, socio-political, and socio-cultural dynamics characteristic of these areas have proven it challenging for them to conform to all requirements of urban sustainability, as evidenced in part by the virtual lack of greenspaces and urban trees. Through a three-tier inquiry of urban tree planting in low-cost housing areas using inductive and deductive mixed methods approaches, the aim of this research was to investigate the barriers to, and enablers of, tree planting in low-cost housing areas, and explore participatory learning opportunities to address the challenges and enhance the enablers. In the first segment, a participatory urban forest governance conceptual framing lens was used to situate the various actors in the development of the low-cost housing area urban forest and the dynamics of their involvement in that regard. Inquiry focused on an overview of tree planting across South Africa using key informant interviews, observations and document analysis. Secondly, distribution of trees, and barriers and enablers of tree planting in selected low-cost housing areas in the Eastern Cape province using household surveys, observations, key informant interviews and document analysis were investigated. Finally, drawing on interventionist methodology and adoption of Cultural-Historical Activity Theory (CHAT), the third segment tested scenarios of tree planting in three different small towns through focus group discussions and knowledge-sharing awareness events about trees and tree planting using an activity systems approach. Findings from the first segment ascertain the national Department of Environment, Forestry and Fisheries (DEFF) as the custodian of forestry, and by extension urban forestry in South Africa. Municipalities are tasked with implementing greening plans and strategies for public space planting, while private businesses collaborate with entities to contribute to tree-planting as part of their Corporate Social Responsibility (CSR). Civil society, including residents and Non-Governmental Organizations (NGOs) also contribute, especially for private space planting. However, there are currently very few initiatives implemented in low-cost housing areas. An assessment of ten tree planting initiatives revealed that the DEFF is the most common partner and stakeholder, and normally provides resources such as funding and trees. Most programs reported having undertaken community engagement before and during the tree planting. The general outcomes of these initiatives were centred on the survival rate of trees, job creation, and development of parks and gardens. Findings from the first part of the second segment, conducted in eight small-medium sized towns in the Eastern Cape, revealed a general lack of trees along streets of both the newly developed and old low-cost housing areas. In the private spaces, most households (52 %) reported having at least one tree in their yard, with households in the older suburbs (60 %) reporting more trees than the newer ones (44 %). Most of these trees (66 %) had been planted as opposed to natural regeneration. Previous participation in urban tree planting programs was low, but 75 % of residents expressed willingness to participate in the future. Municipal officials from these towns corroborated that they do not host tree planting events or initiatives, which was demonstrated by the limited incorporation of urban forestry and urban greening in municipal Integrated Development Plans (IDP). In the second part of the second segment, three groupings of barriers and enablers into biophysical, social, and resources revealed that the most mentioned barriers for the private space were resource barriers. The most prominent barriers were limited space in people’s yards, insufficient funds for tree purchases and associated resources, the lack of equipment, and damage to planted trees. Private space enablers of tree planting suggested include the availability of funds, allocation of space, and changes in attitudes towards trees. According to residents, the most prominent barriers to public space planting include the perceived incompetence of municipalities, limited space on the street, insufficient funds for tree planting programmes, damage to trees in public spaces, crime associated with street trees, and politics. Additionally, municipal officials reported that their efforts to plant trees were hindered by lack of communication and coordination between municipal departments. Residents suggested that enlisting the skills of residents for tree planting, engaging in education and awareness initiatives about trees and tree planting, and changing attitudes towards trees could enable tree planting. Municipal officials opined that education and awareness, revisions to and implementation of Environmental Management Plans, and inter-departmental collaborations and partnerships could improve the prospects for public space planting. Drawing on key findings from the second segment, an intervention to involve communities in tree planting using a case study approach in three towns ensued. Here an activity systems analysis of participatory tree planting initiatives was used. Findings revealed an array of multi-activity systems with multiple and partially overlapping objectives related to tree planting. Residents demonstrated that, with support, they can champion urban tree planting for their suburbs. However, contradictions and tensions within and between various activity systems emerged, creating opportunities for the expansive transformation of an activity that was previously not a priority. This study highlights the current distribution of power and resources in the governance system of the urban forest, ascertains the spatial heterogeneity of urban trees in areas of a similar socio-economic context, and provides lessons for best-practice in tree planting that involves multiple actors. It provides in-depth insights into what constrains tree planting, and highlights the importance of residents in the governance system of urban forests and how this can constrain or advance tree planting. Further research in participatory urban forest governance for a developing country, low-income context could utilize an expansive learning platform as this will provide first-hand experiences into learning what is not yet there, and provide communities with the opportunities to explore and devise localized solutions to the lack of trees in their residential areas.
- Full Text:
- Authors: Gwedla, Nanamhla
- Date: 2020
- Subjects: Urban ecology (Sociology) -- South Africa -- Eastern Cape , Tree planting -- South Africa -- Eastern Cape , Trees in cities -- South Africa -- Eastern Cape , Urban forestry -- Law and legislation -- South Africa -- Eastern Cape , Low-income housing -- South Africa -- Eastern Cape , Cultural Historical Activity Theory (CHAT)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167065 , vital:41434
- Description: The recent pronouncement of low-cost housing areas as sustainable human settlements came with an expectation for their development in line with Sustainable Development Goal (SDG) 11. Unfortunately, the historical legacy and various socio-economic, socio-political, and socio-cultural dynamics characteristic of these areas have proven it challenging for them to conform to all requirements of urban sustainability, as evidenced in part by the virtual lack of greenspaces and urban trees. Through a three-tier inquiry of urban tree planting in low-cost housing areas using inductive and deductive mixed methods approaches, the aim of this research was to investigate the barriers to, and enablers of, tree planting in low-cost housing areas, and explore participatory learning opportunities to address the challenges and enhance the enablers. In the first segment, a participatory urban forest governance conceptual framing lens was used to situate the various actors in the development of the low-cost housing area urban forest and the dynamics of their involvement in that regard. Inquiry focused on an overview of tree planting across South Africa using key informant interviews, observations and document analysis. Secondly, distribution of trees, and barriers and enablers of tree planting in selected low-cost housing areas in the Eastern Cape province using household surveys, observations, key informant interviews and document analysis were investigated. Finally, drawing on interventionist methodology and adoption of Cultural-Historical Activity Theory (CHAT), the third segment tested scenarios of tree planting in three different small towns through focus group discussions and knowledge-sharing awareness events about trees and tree planting using an activity systems approach. Findings from the first segment ascertain the national Department of Environment, Forestry and Fisheries (DEFF) as the custodian of forestry, and by extension urban forestry in South Africa. Municipalities are tasked with implementing greening plans and strategies for public space planting, while private businesses collaborate with entities to contribute to tree-planting as part of their Corporate Social Responsibility (CSR). Civil society, including residents and Non-Governmental Organizations (NGOs) also contribute, especially for private space planting. However, there are currently very few initiatives implemented in low-cost housing areas. An assessment of ten tree planting initiatives revealed that the DEFF is the most common partner and stakeholder, and normally provides resources such as funding and trees. Most programs reported having undertaken community engagement before and during the tree planting. The general outcomes of these initiatives were centred on the survival rate of trees, job creation, and development of parks and gardens. Findings from the first part of the second segment, conducted in eight small-medium sized towns in the Eastern Cape, revealed a general lack of trees along streets of both the newly developed and old low-cost housing areas. In the private spaces, most households (52 %) reported having at least one tree in their yard, with households in the older suburbs (60 %) reporting more trees than the newer ones (44 %). Most of these trees (66 %) had been planted as opposed to natural regeneration. Previous participation in urban tree planting programs was low, but 75 % of residents expressed willingness to participate in the future. Municipal officials from these towns corroborated that they do not host tree planting events or initiatives, which was demonstrated by the limited incorporation of urban forestry and urban greening in municipal Integrated Development Plans (IDP). In the second part of the second segment, three groupings of barriers and enablers into biophysical, social, and resources revealed that the most mentioned barriers for the private space were resource barriers. The most prominent barriers were limited space in people’s yards, insufficient funds for tree purchases and associated resources, the lack of equipment, and damage to planted trees. Private space enablers of tree planting suggested include the availability of funds, allocation of space, and changes in attitudes towards trees. According to residents, the most prominent barriers to public space planting include the perceived incompetence of municipalities, limited space on the street, insufficient funds for tree planting programmes, damage to trees in public spaces, crime associated with street trees, and politics. Additionally, municipal officials reported that their efforts to plant trees were hindered by lack of communication and coordination between municipal departments. Residents suggested that enlisting the skills of residents for tree planting, engaging in education and awareness initiatives about trees and tree planting, and changing attitudes towards trees could enable tree planting. Municipal officials opined that education and awareness, revisions to and implementation of Environmental Management Plans, and inter-departmental collaborations and partnerships could improve the prospects for public space planting. Drawing on key findings from the second segment, an intervention to involve communities in tree planting using a case study approach in three towns ensued. Here an activity systems analysis of participatory tree planting initiatives was used. Findings revealed an array of multi-activity systems with multiple and partially overlapping objectives related to tree planting. Residents demonstrated that, with support, they can champion urban tree planting for their suburbs. However, contradictions and tensions within and between various activity systems emerged, creating opportunities for the expansive transformation of an activity that was previously not a priority. This study highlights the current distribution of power and resources in the governance system of the urban forest, ascertains the spatial heterogeneity of urban trees in areas of a similar socio-economic context, and provides lessons for best-practice in tree planting that involves multiple actors. It provides in-depth insights into what constrains tree planting, and highlights the importance of residents in the governance system of urban forests and how this can constrain or advance tree planting. Further research in participatory urban forest governance for a developing country, low-income context could utilize an expansive learning platform as this will provide first-hand experiences into learning what is not yet there, and provide communities with the opportunities to explore and devise localized solutions to the lack of trees in their residential areas.
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Bat species richness and community composition along a mega-transect in the Okavango river basin:
- Weier, Sina M, Keith, Mark, Neef, Götz G, Parker, Daniel M, Taylor, Peter
- Authors: Weier, Sina M , Keith, Mark , Neef, Götz G , Parker, Daniel M , Taylor, Peter
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149264 , vital:38820 , https://doi.org/10.3390/d12050188
- Description: The Okavango River Basin is a hotspot of bat diversity that requires urgent and adequate protection. To advise future conservation strategies, we investigated the relative importance of a range of potential environmental drivers of bat species richness and functional community composition in the Okavango River Basin. During annual canoe transects along the major rivers, originating in the central Angolan highlands, we recorded more than 25,000 bat echolocation calls from 2015 to 2018. We corrected for possible biases in sampling design and effort.
- Full Text:
- Authors: Weier, Sina M , Keith, Mark , Neef, Götz G , Parker, Daniel M , Taylor, Peter
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149264 , vital:38820 , https://doi.org/10.3390/d12050188
- Description: The Okavango River Basin is a hotspot of bat diversity that requires urgent and adequate protection. To advise future conservation strategies, we investigated the relative importance of a range of potential environmental drivers of bat species richness and functional community composition in the Okavango River Basin. During annual canoe transects along the major rivers, originating in the central Angolan highlands, we recorded more than 25,000 bat echolocation calls from 2015 to 2018. We corrected for possible biases in sampling design and effort.
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BEd foundation phase fourth year student teachers’ self-efficacy beliefs towards teaching mathematics and the self-reported factors that influence these self-efficacy beliefs
- Authors: Harrison, Chloe
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , Mathematics teachers -- Training of -- South Africa , Educational evaluation -- South Africa , Student teachers -- Training of -- South Africa , Student teachers -- Rating of -- South Africa , Social cognitive theory , Self-efficacy
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/147004 , vital:38584
- Description: The underperformance of mathematics teaching and learning is a pressing concern in South Africa. Many foundation phase in-service teachers show inadequate mathematics content knowledge which creates barriers to their learners acquiring adequate mathematics skills. Teacher training programmes offer a key opportunity to improve the instructional practices of teachers at foundation phase level. In order to improve the teaching skills of in-service teachers, one focus must be on teacher training programmes. Unfortunately, there are many foundation phase student teachers who are leaving the profession within the first few years of teaching reportedly due to low levels of motivation. This research investigates the self-efficacy beliefs of pre-service student teachers. It also focuses on foundation phase student teachers as they experience significant challenges to their self-efficacy beliefs in mathematics and mathematics teaching. Self-efficacy is the key theory of the study. It stems from Bandura’s social cognitive theory and is an individual’s judgments about their capabilities, skills and perceived performance. This qualitative research adopts an interpretivist approach which seeks to identify Bed foundation phase fourth year student teachers’ self-efficacy beliefs towards teaching mathematics and the self-reported factors influencing such beliefs. This research found that BEd foundation phase fourth year student teachers have low self-efficacy beliefs towards teaching mathematics. The purpose of this research is to raise awareness of the BEd student teachers’ low self-efficacy beliefs towards teaching mathematics. The results from this research will provide a platform for future intervention research, as well as potentially influencing student teacher training programmes.
- Full Text:
- Authors: Harrison, Chloe
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , Mathematics teachers -- Training of -- South Africa , Educational evaluation -- South Africa , Student teachers -- Training of -- South Africa , Student teachers -- Rating of -- South Africa , Social cognitive theory , Self-efficacy
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/147004 , vital:38584
- Description: The underperformance of mathematics teaching and learning is a pressing concern in South Africa. Many foundation phase in-service teachers show inadequate mathematics content knowledge which creates barriers to their learners acquiring adequate mathematics skills. Teacher training programmes offer a key opportunity to improve the instructional practices of teachers at foundation phase level. In order to improve the teaching skills of in-service teachers, one focus must be on teacher training programmes. Unfortunately, there are many foundation phase student teachers who are leaving the profession within the first few years of teaching reportedly due to low levels of motivation. This research investigates the self-efficacy beliefs of pre-service student teachers. It also focuses on foundation phase student teachers as they experience significant challenges to their self-efficacy beliefs in mathematics and mathematics teaching. Self-efficacy is the key theory of the study. It stems from Bandura’s social cognitive theory and is an individual’s judgments about their capabilities, skills and perceived performance. This qualitative research adopts an interpretivist approach which seeks to identify Bed foundation phase fourth year student teachers’ self-efficacy beliefs towards teaching mathematics and the self-reported factors influencing such beliefs. This research found that BEd foundation phase fourth year student teachers have low self-efficacy beliefs towards teaching mathematics. The purpose of this research is to raise awareness of the BEd student teachers’ low self-efficacy beliefs towards teaching mathematics. The results from this research will provide a platform for future intervention research, as well as potentially influencing student teacher training programmes.
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Between nationalism and transnationalism: entanglements of history, individual narrative, and memory in diaspora spaces in selected transnational fiction
- Authors: Bosman, Sean James
- Date: 2020
- Subjects: Literature and transnationalism , Gurnah, Abdulrazak, 1948- , Gurnah, Abdulrazak, 1948- -- By the sea , Gurnah, Abdulrazak, 1948- -- Gravel heart , Nguyen, Viet Thanh, 1971- , Nguyen, Viet Thanh, 1971- -- The sympathizer , Nguyen, Viet Thanh, 1971- -- The refugees , Urrea, Luis Alberto , Urrea, Luis Alberto -- The house of broken angels , Urrea, Luis Alberto -- The water museum
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140932 , vital:37930
- Description: This thesis offers close readings and a comparative analysis of selected works by Abdulrazak Gurnah, Viet Thanh Nguyen, and Luis Alberto Urrea. The selected primary texts used are Gurnah’s By the Sea (2000) and Gravel Heart (2017), Nguyen’s The Sympathizer (2015) and The Refugees (2017), and Urrea’s The Water Museum (2015) and The House of Broken Angels (2018). Analyses are informed by a conceptual framework that draws on critical works by Avtar Brah, J. U. Jacobs, Sarah Nuttall, Homi K. Bhabha, Judith Butler, Stuart Hall, Paul Ricoeur, Viet Thanh Nguyen, and Christopher B. Patterson. These theories are deployed to analyse how the selected works engage with the entanglements of history, individual narratives, and memory in the diaspora spaces they articulate. The thesis argues that the selected works indicate an emerging subgenre within the broader category of transnational literature. This subgenre rejects disempowering interpolations of transnational identities. Instead, it prioritises ethical forms of memory. These acknowledge that transnational subjects share at least partial accountability for the precarity they experience in diaspora spaces. The selected literature limns how this may be accomplished by rejecting the label of victim. In so doing, the selected literature also suggests that the elevation of transnationals to full ethical agency would enable them to exercise power in their diaspora spaces. All three authorial projects studied here also give rise to uncomfortable juxtapositions that suggest a mounting fear that, as nationalisms become more pronounced in the UK and the USA, transnationals may have to re-experience conditions from which they have already fled. The thesis concludes by identifying four additional areas of confluence amongst the selected literature worthy of future study.
- Full Text:
- Authors: Bosman, Sean James
- Date: 2020
- Subjects: Literature and transnationalism , Gurnah, Abdulrazak, 1948- , Gurnah, Abdulrazak, 1948- -- By the sea , Gurnah, Abdulrazak, 1948- -- Gravel heart , Nguyen, Viet Thanh, 1971- , Nguyen, Viet Thanh, 1971- -- The sympathizer , Nguyen, Viet Thanh, 1971- -- The refugees , Urrea, Luis Alberto , Urrea, Luis Alberto -- The house of broken angels , Urrea, Luis Alberto -- The water museum
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140932 , vital:37930
- Description: This thesis offers close readings and a comparative analysis of selected works by Abdulrazak Gurnah, Viet Thanh Nguyen, and Luis Alberto Urrea. The selected primary texts used are Gurnah’s By the Sea (2000) and Gravel Heart (2017), Nguyen’s The Sympathizer (2015) and The Refugees (2017), and Urrea’s The Water Museum (2015) and The House of Broken Angels (2018). Analyses are informed by a conceptual framework that draws on critical works by Avtar Brah, J. U. Jacobs, Sarah Nuttall, Homi K. Bhabha, Judith Butler, Stuart Hall, Paul Ricoeur, Viet Thanh Nguyen, and Christopher B. Patterson. These theories are deployed to analyse how the selected works engage with the entanglements of history, individual narratives, and memory in the diaspora spaces they articulate. The thesis argues that the selected works indicate an emerging subgenre within the broader category of transnational literature. This subgenre rejects disempowering interpolations of transnational identities. Instead, it prioritises ethical forms of memory. These acknowledge that transnational subjects share at least partial accountability for the precarity they experience in diaspora spaces. The selected literature limns how this may be accomplished by rejecting the label of victim. In so doing, the selected literature also suggests that the elevation of transnationals to full ethical agency would enable them to exercise power in their diaspora spaces. All three authorial projects studied here also give rise to uncomfortable juxtapositions that suggest a mounting fear that, as nationalisms become more pronounced in the UK and the USA, transnationals may have to re-experience conditions from which they have already fled. The thesis concludes by identifying four additional areas of confluence amongst the selected literature worthy of future study.
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Between past and future: memory and mourning in the stories of Okwiri Oduor and Ndinda Kioko
- Authors: Awuor, Nicholas Amol
- Date: 2020
- Subjects: Oduor, Okwiri -- Criticism and interpretation , Oduor, Okwiri -- The plea bargain , Oduor, Okwiri -- My father's head , Oduor, Okwiri -- Rag doll , Kioko, Ndinda -- Criticism and interpretation , Kioko, Ndinda -- Sometime Before Maulidi , Kioko, Ndinda -- Some Freedom Dreams , Authors, Kenyan -- Criticism and interpretation , Kenyan fiction (English) -- History and criticism , Kenyan literature (English) -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/163168 , vital:41015
- Description: This study investigates the literary activities of two emerging female Kenyan writers, Claudette Okwiri Oduor and Jacqueline Ndinda Kioko, both of whom are award-winning authors. Oduor won the 2014 Caine Prize for African Writing while Kioko bagged the Wasafiri New Writing Fiction Award 2017. It examines specifically how the writers deal with memory and mourning in negotiating between the past and future. I explore how their fictional and non-fictional narratives assist individuals and groups to confront loss, reconstruct new identities, and renegotiate belonging amidst personal and social upheaval. The fictional narratives at the centre of this research are Oduor’s “The Plea Bargain” (2011), “My Father’s Head” (2013) and “Rag Doll” (2014), and Kioko’s “Sometime Before Maulidi” (2014) and “Some Freedom Dreams” (2017). The study explores the themes of mental illness, existential crisis, and fragmentation, and considers bereavement, queer relationships, cultural freedom, and social recognition. The research further considers the active participation of these two writers in Kenya’s contemporary literary-cultural conversations, which span different genres and various media platforms, including blogs, YouTube clips, online magazines, and social media networks in dialogue with other writers. I trace the significance of the literary-cultural link these authors have with their local, continental, and global counterparts in countries like Uganda, Nigeria, and South Africa. The link finds expression through their (in)direct association with some of the new online publishing outlets in Kenya like Jalada Africa, Enkare Review, and Kikwetu. More importantly, their shared participation in and association with such international awards and scholarships as the Commonwealth Short Story Prize, Kwani Trust Manuscript Project, and Miles Morland Foundation is integral in apprehending contemporary literary exchanges and multidirectional flows of publishing in Africa and beyond. I equally illustrate how mentorship of younger writers through local writers’ organisations and collectives like AMKA and Writivism help in the formation of an alternative canon other than the mainstream. The study affirms that the authors seem to transcend the boundaries of production and circulation by fluidly moving between electronic and non-electronic platforms, thus mimicking the memory production of remembering, repeating, and working through.
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- Authors: Awuor, Nicholas Amol
- Date: 2020
- Subjects: Oduor, Okwiri -- Criticism and interpretation , Oduor, Okwiri -- The plea bargain , Oduor, Okwiri -- My father's head , Oduor, Okwiri -- Rag doll , Kioko, Ndinda -- Criticism and interpretation , Kioko, Ndinda -- Sometime Before Maulidi , Kioko, Ndinda -- Some Freedom Dreams , Authors, Kenyan -- Criticism and interpretation , Kenyan fiction (English) -- History and criticism , Kenyan literature (English) -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/163168 , vital:41015
- Description: This study investigates the literary activities of two emerging female Kenyan writers, Claudette Okwiri Oduor and Jacqueline Ndinda Kioko, both of whom are award-winning authors. Oduor won the 2014 Caine Prize for African Writing while Kioko bagged the Wasafiri New Writing Fiction Award 2017. It examines specifically how the writers deal with memory and mourning in negotiating between the past and future. I explore how their fictional and non-fictional narratives assist individuals and groups to confront loss, reconstruct new identities, and renegotiate belonging amidst personal and social upheaval. The fictional narratives at the centre of this research are Oduor’s “The Plea Bargain” (2011), “My Father’s Head” (2013) and “Rag Doll” (2014), and Kioko’s “Sometime Before Maulidi” (2014) and “Some Freedom Dreams” (2017). The study explores the themes of mental illness, existential crisis, and fragmentation, and considers bereavement, queer relationships, cultural freedom, and social recognition. The research further considers the active participation of these two writers in Kenya’s contemporary literary-cultural conversations, which span different genres and various media platforms, including blogs, YouTube clips, online magazines, and social media networks in dialogue with other writers. I trace the significance of the literary-cultural link these authors have with their local, continental, and global counterparts in countries like Uganda, Nigeria, and South Africa. The link finds expression through their (in)direct association with some of the new online publishing outlets in Kenya like Jalada Africa, Enkare Review, and Kikwetu. More importantly, their shared participation in and association with such international awards and scholarships as the Commonwealth Short Story Prize, Kwani Trust Manuscript Project, and Miles Morland Foundation is integral in apprehending contemporary literary exchanges and multidirectional flows of publishing in Africa and beyond. I equally illustrate how mentorship of younger writers through local writers’ organisations and collectives like AMKA and Writivism help in the formation of an alternative canon other than the mainstream. The study affirms that the authors seem to transcend the boundaries of production and circulation by fluidly moving between electronic and non-electronic platforms, thus mimicking the memory production of remembering, repeating, and working through.
- Full Text:
Between past and future: memory and mourning in the stories of Okwiri Oduor and Ndinda Kioko
- Authors: Awour, Nicholas Amol
- Date: 2020
- Subjects: Women authors, Kenyan , Oduor, Okwiri -- The plea bargain , Oduor, Okwiri -- My father's head , Oduor, Okwiri -- Rag doll , Kioko, Ndinda -- Sometime before Maulidi , Kioko, Ndinda -- Some freedom dreams , Women and literature -- Africa , Bereavement -- Fiction , Culture in literature , Liberty in literature
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/161229 , vital:40608
- Description: This study investigates the literary activities of two emerging female Kenyan writers, Claudette Okwiri Oduor and Jacqueline Ndinda Kioko, both of whom are award-winning authors. Oduor won the 2014 Caine Prize for African Writing while Kioko bagged the Wasafiri New Writing Fiction Award 2017. It examines specifically how the writers deal with memory and mourning in negotiating between the past and future. I explore how their fictional and non-fictional narratives assist individuals and groups to confront loss, reconstruct new identities, and renegotiate belonging amidst personal and social upheaval. The fictional narratives at the centre of this research are Oduor’s “The Plea Bargain” (2011), “My Father’s Head” (2013) and “Rag Doll” (2014), and Kioko’s “Sometime Before Maulidi” (2014) and “Some Freedom Dreams” (2017). The study explores the themes of mental illness, existential crisis, and fragmentation, and considers bereavement, queer relationships, cultural freedom, and social recognition. The research further considers the active participation of these two writers in Kenya’s contemporary literary-cultural conversations, which span different genres and various media platforms, including blogs, YouTube clips, online magazines, and social media networks in dialogue with other writers. . I trace the significance of the literary-cultural link these authors have with their local, continental, and global counterparts in countries like Uganda, Nigeria, and South Africa. The link finds expression through their (in)direct association with some of the new online publishing outlets in Kenya like Jalada Africa, Enkare Review, and Kikwetu. More importantly, their shared participation in and association with such international awards and scholarships as the Commonwealth Short Story Prize, Kwani Trust Manuscript Project, and Miles Morland Foundation is integral in apprehending contemporary literary exchanges and multidirectional flows of publishing in Africa and beyond. I equally illustrate how mentorship of younger writers through local writers’ organisations and collectives like AMKA and Writivism help in the formation of an alternative canon other than the mainstream. The study affirms that the authors seem to transcend the boundaries of production and circulation by fluidly moving between electronic and non-electronic platforms, thus mimicking the memory production of remembering, repeating, and working through.
- Full Text:
- Authors: Awour, Nicholas Amol
- Date: 2020
- Subjects: Women authors, Kenyan , Oduor, Okwiri -- The plea bargain , Oduor, Okwiri -- My father's head , Oduor, Okwiri -- Rag doll , Kioko, Ndinda -- Sometime before Maulidi , Kioko, Ndinda -- Some freedom dreams , Women and literature -- Africa , Bereavement -- Fiction , Culture in literature , Liberty in literature
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/161229 , vital:40608
- Description: This study investigates the literary activities of two emerging female Kenyan writers, Claudette Okwiri Oduor and Jacqueline Ndinda Kioko, both of whom are award-winning authors. Oduor won the 2014 Caine Prize for African Writing while Kioko bagged the Wasafiri New Writing Fiction Award 2017. It examines specifically how the writers deal with memory and mourning in negotiating between the past and future. I explore how their fictional and non-fictional narratives assist individuals and groups to confront loss, reconstruct new identities, and renegotiate belonging amidst personal and social upheaval. The fictional narratives at the centre of this research are Oduor’s “The Plea Bargain” (2011), “My Father’s Head” (2013) and “Rag Doll” (2014), and Kioko’s “Sometime Before Maulidi” (2014) and “Some Freedom Dreams” (2017). The study explores the themes of mental illness, existential crisis, and fragmentation, and considers bereavement, queer relationships, cultural freedom, and social recognition. The research further considers the active participation of these two writers in Kenya’s contemporary literary-cultural conversations, which span different genres and various media platforms, including blogs, YouTube clips, online magazines, and social media networks in dialogue with other writers. . I trace the significance of the literary-cultural link these authors have with their local, continental, and global counterparts in countries like Uganda, Nigeria, and South Africa. The link finds expression through their (in)direct association with some of the new online publishing outlets in Kenya like Jalada Africa, Enkare Review, and Kikwetu. More importantly, their shared participation in and association with such international awards and scholarships as the Commonwealth Short Story Prize, Kwani Trust Manuscript Project, and Miles Morland Foundation is integral in apprehending contemporary literary exchanges and multidirectional flows of publishing in Africa and beyond. I equally illustrate how mentorship of younger writers through local writers’ organisations and collectives like AMKA and Writivism help in the formation of an alternative canon other than the mainstream. The study affirms that the authors seem to transcend the boundaries of production and circulation by fluidly moving between electronic and non-electronic platforms, thus mimicking the memory production of remembering, repeating, and working through.
- Full Text:
Biodiversity conservation and rural livelihoods across four nature reserves in the Eastern Cape Province, South Africa: Striving towards a balance between livelihoods and conservation
- Authors: Angwenyi, Daniel
- Date: 2020
- Subjects: National parks and reserves -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape , Biodiversity conservation -- South Africa -- Eastern Cape , Rural population -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/138551 , vital:37649
- Description: The realisation that biodiversity is being lost at alarming rates, and that intact ecosystems are essential for ecological functioning and sustenance of human life, has led to biodiversity taking centre stage in national and international agencies’ environmental talks agendas. Protected areas are viable option to stem biodiversity loss. However, the establishment of protected areas might have negative impacts on communities living adjacent to them, leading to poor relations and frequent conflicts between these communities and the managers of protected areas. The Eastern Cape Province has twenty-one nature reserves and three national parks. Since the province is rural, the assumption was likelihood that households in the province depended on natural resources, specifically non-timber forest products for their day-to-day needs. Therefore, it was hypothesised that conserving natural resources, was likely to negatively impact on the livelihoods of most households adjacent to these areas, which in turn would influence their perceptions towards these resources and eventually the effectiveness of conservation efforts. This study aimed at examining the relationship between biodiversity conservation and rural livelihoods in the Eastern Cape Province, South Africa, focusing on four nature reserves – Tsolwana, Hluleka, Mkambati and Great Fish River. The objectives of the study were to: I I. Compare the vegetation productivity inside and outside, as well as land cover change in four nature reserves, as an indicator of conservation effectiveness. II II. Evaluate the relationship between biodiversity conservation and livelihoods in four nature reserves. III III. Evaluate how people’s expectations of nature reserves and perceptions towards nature reserve influence their support of conservation activities. Four hundred semi-structured questionnaires were administered to household heads of communities living at various distances from the four nature reserves, using a gradient design (based on distance). The motive of using distance was to assess whether livelihood status varied with distance from the nature reserves, since data on livelihood before the reserves’ establishment could not be obtained. Through a questionnaire survey, data on demographic information, livelihood assets, livelihood activities, livelihood strategies, livelihood trends, and impacts of the reserves on local communities were gathered. Focus group interviews were also conducted to complement the household surveys. A chi-square test was used to test if there was a relationship between distance from the reserves’ boundaries and local communities’ state of livelihoods. NVivo was used to analyse qualitative data Themes substantiated using literature. The study finds that the reserves did not have any impact on livelihood assets because most households in the study area did not directly depend on the resources found in the reserves. These households depended mostly on government grants and remittances from relatives working in other areas in the country. The reserves, however, supplied some goods and services to local communities, including meat, jobs, water, building materials, security from wild animals, education, skills development, and recreation. There were also a number of negative impacts associated with the reserves including resource use restrictions, harassment by reserves management, killing of domestic animals, and attacks on humans by wild animals escaping from the reserve. The majority (60%) of locals had substantive knowledge of the reserves’ role because of this awareness, 79% were supportive of reserves. However, there were mixed views by locals on the best way to manage these reserves. The most dominant view was that natural resources should be preserved for future generations, while meeting the current generation’s livelihood needs. Other lesser views included that the reserves’ management should involve locals in the management structures, either as active members or through consultation. Similarly, there were people feeling that the reserve is an obstacle to their livelihoods and should be closed and the land returned to the rightful owners. The vegetation productivity was better inside as compared to the outside the reserves. This activity also improved in the sixteen (16) years under assessment. This imply that the ecological functionality of the reserves is better than the surrounding areas and is improving with time. The research recommended that local communities could be an asset in conservation since most of them were in favour of the reserves. This, however, will need reserve managers to form workable partnerships with these communities, where the rights and responsibilities for both parties are defined. Besides these partnerships, lease agreements between local communities and reserves management to enhance benefits to the communities could encourage local communities to take pride in the natural resources within the reserves. This will ultimately becoming stewards to these resources. Development of tourism infrastructure such as curio shops and convenience stores to enhance livelihood opportunities could also help. For the local communities to be well represented it is important that the committees representing them in the various reserve matters be expanded and democratically elected. Where necessary, community awareness programmes on the importance of the reserves and the roles of local communities should be implemented.
- Full Text:
- Authors: Angwenyi, Daniel
- Date: 2020
- Subjects: National parks and reserves -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape , Biodiversity conservation -- South Africa -- Eastern Cape , Rural population -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/138551 , vital:37649
- Description: The realisation that biodiversity is being lost at alarming rates, and that intact ecosystems are essential for ecological functioning and sustenance of human life, has led to biodiversity taking centre stage in national and international agencies’ environmental talks agendas. Protected areas are viable option to stem biodiversity loss. However, the establishment of protected areas might have negative impacts on communities living adjacent to them, leading to poor relations and frequent conflicts between these communities and the managers of protected areas. The Eastern Cape Province has twenty-one nature reserves and three national parks. Since the province is rural, the assumption was likelihood that households in the province depended on natural resources, specifically non-timber forest products for their day-to-day needs. Therefore, it was hypothesised that conserving natural resources, was likely to negatively impact on the livelihoods of most households adjacent to these areas, which in turn would influence their perceptions towards these resources and eventually the effectiveness of conservation efforts. This study aimed at examining the relationship between biodiversity conservation and rural livelihoods in the Eastern Cape Province, South Africa, focusing on four nature reserves – Tsolwana, Hluleka, Mkambati and Great Fish River. The objectives of the study were to: I I. Compare the vegetation productivity inside and outside, as well as land cover change in four nature reserves, as an indicator of conservation effectiveness. II II. Evaluate the relationship between biodiversity conservation and livelihoods in four nature reserves. III III. Evaluate how people’s expectations of nature reserves and perceptions towards nature reserve influence their support of conservation activities. Four hundred semi-structured questionnaires were administered to household heads of communities living at various distances from the four nature reserves, using a gradient design (based on distance). The motive of using distance was to assess whether livelihood status varied with distance from the nature reserves, since data on livelihood before the reserves’ establishment could not be obtained. Through a questionnaire survey, data on demographic information, livelihood assets, livelihood activities, livelihood strategies, livelihood trends, and impacts of the reserves on local communities were gathered. Focus group interviews were also conducted to complement the household surveys. A chi-square test was used to test if there was a relationship between distance from the reserves’ boundaries and local communities’ state of livelihoods. NVivo was used to analyse qualitative data Themes substantiated using literature. The study finds that the reserves did not have any impact on livelihood assets because most households in the study area did not directly depend on the resources found in the reserves. These households depended mostly on government grants and remittances from relatives working in other areas in the country. The reserves, however, supplied some goods and services to local communities, including meat, jobs, water, building materials, security from wild animals, education, skills development, and recreation. There were also a number of negative impacts associated with the reserves including resource use restrictions, harassment by reserves management, killing of domestic animals, and attacks on humans by wild animals escaping from the reserve. The majority (60%) of locals had substantive knowledge of the reserves’ role because of this awareness, 79% were supportive of reserves. However, there were mixed views by locals on the best way to manage these reserves. The most dominant view was that natural resources should be preserved for future generations, while meeting the current generation’s livelihood needs. Other lesser views included that the reserves’ management should involve locals in the management structures, either as active members or through consultation. Similarly, there were people feeling that the reserve is an obstacle to their livelihoods and should be closed and the land returned to the rightful owners. The vegetation productivity was better inside as compared to the outside the reserves. This activity also improved in the sixteen (16) years under assessment. This imply that the ecological functionality of the reserves is better than the surrounding areas and is improving with time. The research recommended that local communities could be an asset in conservation since most of them were in favour of the reserves. This, however, will need reserve managers to form workable partnerships with these communities, where the rights and responsibilities for both parties are defined. Besides these partnerships, lease agreements between local communities and reserves management to enhance benefits to the communities could encourage local communities to take pride in the natural resources within the reserves. This will ultimately becoming stewards to these resources. Development of tourism infrastructure such as curio shops and convenience stores to enhance livelihood opportunities could also help. For the local communities to be well represented it is important that the committees representing them in the various reserve matters be expanded and democratically elected. Where necessary, community awareness programmes on the importance of the reserves and the roles of local communities should be implemented.
- Full Text:
Bioelectrocatalysis and surface analysis of gold coated with nickel oxide/hydroxide and glucose oxidase towards detection of glucose:
- Njoko, Nqobile, Louzada, Marcel, Britton, Jonathan, Khene, Samson, Nyokong, Tebello, Mashazi, Philani
- Authors: Njoko, Nqobile , Louzada, Marcel , Britton, Jonathan , Khene, Samson , Nyokong, Tebello , Mashazi, Philani
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150071 , vital:38937 , https://doi.org/10.1016/j.colsurfb.2020.110981
- Description: The fabricating of metal oxide thin films onto conducting surfaces continues to grow and their potential applications as surfaces for biosensor applications is of paramount importance. The correct orientation of glucose oxidase redox enzymes yields very important biointerfaces capable of selectively detecting D-glucose as a measure of blood sugar for healthy and diabetic sick patients. The electrodeposition of redox enzymes, such as glucose oxidase enzymes, onto gold electrode surfaces pre-modified with nickel oxide was investigated in this work.
- Full Text:
- Authors: Njoko, Nqobile , Louzada, Marcel , Britton, Jonathan , Khene, Samson , Nyokong, Tebello , Mashazi, Philani
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150071 , vital:38937 , https://doi.org/10.1016/j.colsurfb.2020.110981
- Description: The fabricating of metal oxide thin films onto conducting surfaces continues to grow and their potential applications as surfaces for biosensor applications is of paramount importance. The correct orientation of glucose oxidase redox enzymes yields very important biointerfaces capable of selectively detecting D-glucose as a measure of blood sugar for healthy and diabetic sick patients. The electrodeposition of redox enzymes, such as glucose oxidase enzymes, onto gold electrode surfaces pre-modified with nickel oxide was investigated in this work.
- Full Text:
Biogeographic patterns of endolithic cyanobacteria and their negative impacts on mussels along the South African coast
- Authors: Ndhlovu, Aldwin
- Date: 2020
- Subjects: Cyanobacteria -- South Africa , Cyanobacteria -- Geographical distribution , Prokaryotes -- South Africa , Mexilhao mussel -- South Africa , Mytilus galloprovincialis -- South Africa , Coastal biology -- South Africa , Coastal ecology -- South Africa , Mussels -- Geographical distribution , Mussels -- Predators of , Mussels -- Mortality -- South Africa , Mussels -- Ecology -- South Africa , Mussels -- Growth -- South Africa , Mussels -- Fertility -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/144656 , vital:38367
- Description: Endolithic cyanobacterial species occur in a wide range of environments including cold and hot deserts as well as marine systems where they attack biological material such as corals and the shells of molluscs including limpets, mussels and abalone. Endoliths live as parasites in mussel shells, where they erode and extract calcium carbonate leading to shell weakening, creating fracture holes that lead to shell collapse and death, but they also have positive effects when they lead to discolouration of mussel shells hence giving them the ability to reduce stressful heat gain during periods of extreme heat stress. Mussels are ecological engineers on which the abundance and diversity of associated species assemblages depend. Understanding how endolithic cyanobacteria affect mussels will not only help in predicting future patterns of mussel abundances, but also future patterns of the infauna that depend on them. Firstly, I identified endolithic species infesting mussels and assessed the prevalence of endolithic parasitism in two intertidal mussel species in South Africa, the native Perna perna and the invasive Mytilus galloprovincialis. Large-scale surveys of endolithic infestation of mussels were conducted along 2500 km of the South African coast, covering three biogeographic regions: the subtropical east coast, dominated by P. perna, the warm temperate south coast where the indigenous species coexists with M. galloprovincialis, and the cool temperate west coast which is dominated by M. galloprovincialis. The prevalence of endolithic infestation was higher in the cool temperate bioregion than in the warm temperate and subtropical bioregions which did not differ and for P. perna endolithic species assemblages revealed clear groupings by bioregion. Results for endolithic induced mortality followed the same trend, with no significant difference between the two mussel species where they coexist and these results attribute biogeography of endoliths to environmental factors rather than host identity. Secondly, I assessed energy budgets of infested and clean mussels, to evaluate the energetic cost of infestation. This involved measuring energy acquisition, expenditure, calculating scope for growth and lethal temperatures (LT50s). The results revealed that endolithic cyanobacteria have a negative effect on scope for growth due to increased metabolic rates for infested mussels, with no effect of endoliths on the rates or efficiency of energy acquisition through filtration and no effect on lethal temperatures. The effects of infestation were then examined in more detail through a qualitative and quantitative analysis of mussel gonads and byssal attachment strength to the substratum. Endolithic infestation was found to affect reproduction by affecting the size (mass) of gonads, but not the density of eggs within them. Attachment strength was affected by endolithic infestation with very infested mussels requiring much less force to detach them from the substratum compared to mussels with low or no infestation. These results show that endolithic infestation affects mussel fitness by directly affecting attachment strength and by reducing their reproductive output. Thirdly, endolithic succession within mussel shells was examined by assessing endolithic species composition in different regions of the shell and as a function of time. The results on the spatial distribution of endolith species within a shell supported those for temporal succession in shells deployed in the field. Endolithic species that were early colonists of clean shells were similar to those that were found in the distal edge, the new and growing region of the shell and species that arrived late in succession were similar to endolithic species found near the umbo, the oldest region of the shell. Overall, the study shows that endolithic cyanobacteria show the effects of biogeography on species distribution and clear patterns of succession within mussel shells. Cyanobacteria affect mussels negatively; they lead to low scope for growth and hence low growth rates, low reproductive output and reduced attachment strength for infested mussels. This, in turn is expected to have indirect consequences for other species that rely on mussels as ecological engineers for their survival.
- Full Text:
- Authors: Ndhlovu, Aldwin
- Date: 2020
- Subjects: Cyanobacteria -- South Africa , Cyanobacteria -- Geographical distribution , Prokaryotes -- South Africa , Mexilhao mussel -- South Africa , Mytilus galloprovincialis -- South Africa , Coastal biology -- South Africa , Coastal ecology -- South Africa , Mussels -- Geographical distribution , Mussels -- Predators of , Mussels -- Mortality -- South Africa , Mussels -- Ecology -- South Africa , Mussels -- Growth -- South Africa , Mussels -- Fertility -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/144656 , vital:38367
- Description: Endolithic cyanobacterial species occur in a wide range of environments including cold and hot deserts as well as marine systems where they attack biological material such as corals and the shells of molluscs including limpets, mussels and abalone. Endoliths live as parasites in mussel shells, where they erode and extract calcium carbonate leading to shell weakening, creating fracture holes that lead to shell collapse and death, but they also have positive effects when they lead to discolouration of mussel shells hence giving them the ability to reduce stressful heat gain during periods of extreme heat stress. Mussels are ecological engineers on which the abundance and diversity of associated species assemblages depend. Understanding how endolithic cyanobacteria affect mussels will not only help in predicting future patterns of mussel abundances, but also future patterns of the infauna that depend on them. Firstly, I identified endolithic species infesting mussels and assessed the prevalence of endolithic parasitism in two intertidal mussel species in South Africa, the native Perna perna and the invasive Mytilus galloprovincialis. Large-scale surveys of endolithic infestation of mussels were conducted along 2500 km of the South African coast, covering three biogeographic regions: the subtropical east coast, dominated by P. perna, the warm temperate south coast where the indigenous species coexists with M. galloprovincialis, and the cool temperate west coast which is dominated by M. galloprovincialis. The prevalence of endolithic infestation was higher in the cool temperate bioregion than in the warm temperate and subtropical bioregions which did not differ and for P. perna endolithic species assemblages revealed clear groupings by bioregion. Results for endolithic induced mortality followed the same trend, with no significant difference between the two mussel species where they coexist and these results attribute biogeography of endoliths to environmental factors rather than host identity. Secondly, I assessed energy budgets of infested and clean mussels, to evaluate the energetic cost of infestation. This involved measuring energy acquisition, expenditure, calculating scope for growth and lethal temperatures (LT50s). The results revealed that endolithic cyanobacteria have a negative effect on scope for growth due to increased metabolic rates for infested mussels, with no effect of endoliths on the rates or efficiency of energy acquisition through filtration and no effect on lethal temperatures. The effects of infestation were then examined in more detail through a qualitative and quantitative analysis of mussel gonads and byssal attachment strength to the substratum. Endolithic infestation was found to affect reproduction by affecting the size (mass) of gonads, but not the density of eggs within them. Attachment strength was affected by endolithic infestation with very infested mussels requiring much less force to detach them from the substratum compared to mussels with low or no infestation. These results show that endolithic infestation affects mussel fitness by directly affecting attachment strength and by reducing their reproductive output. Thirdly, endolithic succession within mussel shells was examined by assessing endolithic species composition in different regions of the shell and as a function of time. The results on the spatial distribution of endolith species within a shell supported those for temporal succession in shells deployed in the field. Endolithic species that were early colonists of clean shells were similar to those that were found in the distal edge, the new and growing region of the shell and species that arrived late in succession were similar to endolithic species found near the umbo, the oldest region of the shell. Overall, the study shows that endolithic cyanobacteria show the effects of biogeography on species distribution and clear patterns of succession within mussel shells. Cyanobacteria affect mussels negatively; they lead to low scope for growth and hence low growth rates, low reproductive output and reduced attachment strength for infested mussels. This, in turn is expected to have indirect consequences for other species that rely on mussels as ecological engineers for their survival.
- Full Text:
Bioinformatic analysis of Aminoacyl tRNA Synthetases as potential antimalarial drug targets
- Authors: Nyamai, Dorothy Wavinya
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164579 , vital:41142 , doi:10.21504/10962/164579
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Authors: Nyamai, Dorothy Wavinya
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164579 , vital:41142 , doi:10.21504/10962/164579
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
Biology, stock assessment and angler attitudes towards the introduction of slot size limits for a recreationally important species Sparodon durbanensis (Sparidae) in South Africa
- Authors: Hewett, Kyle
- Date: 2020
- Subjects: Sparidae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48389 , vital:40855
- Description: Sparodon durbanensis (white musselcracker) is an endemic fish species in the Family Sparidae found in shallow (< 20 m) coastal waters from the Western Cape to KwaZulu-Natal. It is large-growing, late-maturing, long-lived and is a popular target species in the South African marine shore-based line and spear fisheries. Management regulations for the species have remained the same for over two decades despite anecdotal information of population declines. However, since the last life history-information for S. durbanensis was collected in the late 1980s, there is a paucity of contemporary information needed to inform wise management. The aim of this study was to collect contemporary socio-ecological information on the species and its fishery in order to better inform the management of the species. In order to do this, the growth-rate of historical and contemporary samples of Sparodon durbanensis was compared, a length-based stock assessment was performed and the knowledge and attitudes of anglers towards the introduction of improved regulations were investigated. The growth-rate was compared using otolith width as a proxy for fish growth. It was found that the growth-rate had remained relatively stable between 1963 and 2010, suggesting that S. durbanensis may be resilient to the increasing levels of environmental variability observed throughout its range and that the historical growth parameters determined for this species may remain applicable for contemporary stock assessment. The batch fecundity was determined for 50 mm size classes and used to estimate the percentage cumulative population batch fecundity using historical 803 mm FL (904 mm TL) and contemporary 776 mm FL (874 mm TL) length structure, respectively. Based on these observations a suitable harvest slot limit of 600-850 mm TL was suggested. A Length-Based Spawning Potential Ratio (SPR) model was used to provide the first formal stock assessment for S. durbanensis. The input parameters of M/k=1.44, L∞=1021 mm FL, L50=350 mm FL and L95=800 mm FL and length composition data comprising of 134 lengths obtained from a collection of competitive angling catches, estimated a SPR of 41%, which is above the 40% target reference point. A total of 126 online and face– to-face, replica questionnaires were completed by spearfishermen and recreational shore anglers. Responses indicated that anglers that target S. durbanensis are generally a specialized group who are knowledgeable about the biology and ecology of the species and are passionate about the conservation of the species. Participants indicated that Marine Protected Areas are likely the most effective regulation in the current suite of regulations used to manage the fishery and suggested that poor law enforcement was the major factor inhibiting the efficacy of fishery regulations. New proposed regulations, such as a harvest slot limit (and particularly the one between 600-850 mm TL) for S. durbanensis, was well supported, however participants suggested that non-compliance was a concern. Although, the SPR remained above the 40% target reference point, further declines in the stock status should be prevented through the implementation of a 600-850 mm TL harvest slot limit. Based on the findings of this study, this limit should provide protection against both growth and recruitment overfishing by providing protection to sexually immature, fast growing fish and to large adults that contribute the greatest proportion to population replenishment.
- Full Text:
- Authors: Hewett, Kyle
- Date: 2020
- Subjects: Sparidae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48389 , vital:40855
- Description: Sparodon durbanensis (white musselcracker) is an endemic fish species in the Family Sparidae found in shallow (< 20 m) coastal waters from the Western Cape to KwaZulu-Natal. It is large-growing, late-maturing, long-lived and is a popular target species in the South African marine shore-based line and spear fisheries. Management regulations for the species have remained the same for over two decades despite anecdotal information of population declines. However, since the last life history-information for S. durbanensis was collected in the late 1980s, there is a paucity of contemporary information needed to inform wise management. The aim of this study was to collect contemporary socio-ecological information on the species and its fishery in order to better inform the management of the species. In order to do this, the growth-rate of historical and contemporary samples of Sparodon durbanensis was compared, a length-based stock assessment was performed and the knowledge and attitudes of anglers towards the introduction of improved regulations were investigated. The growth-rate was compared using otolith width as a proxy for fish growth. It was found that the growth-rate had remained relatively stable between 1963 and 2010, suggesting that S. durbanensis may be resilient to the increasing levels of environmental variability observed throughout its range and that the historical growth parameters determined for this species may remain applicable for contemporary stock assessment. The batch fecundity was determined for 50 mm size classes and used to estimate the percentage cumulative population batch fecundity using historical 803 mm FL (904 mm TL) and contemporary 776 mm FL (874 mm TL) length structure, respectively. Based on these observations a suitable harvest slot limit of 600-850 mm TL was suggested. A Length-Based Spawning Potential Ratio (SPR) model was used to provide the first formal stock assessment for S. durbanensis. The input parameters of M/k=1.44, L∞=1021 mm FL, L50=350 mm FL and L95=800 mm FL and length composition data comprising of 134 lengths obtained from a collection of competitive angling catches, estimated a SPR of 41%, which is above the 40% target reference point. A total of 126 online and face– to-face, replica questionnaires were completed by spearfishermen and recreational shore anglers. Responses indicated that anglers that target S. durbanensis are generally a specialized group who are knowledgeable about the biology and ecology of the species and are passionate about the conservation of the species. Participants indicated that Marine Protected Areas are likely the most effective regulation in the current suite of regulations used to manage the fishery and suggested that poor law enforcement was the major factor inhibiting the efficacy of fishery regulations. New proposed regulations, such as a harvest slot limit (and particularly the one between 600-850 mm TL) for S. durbanensis, was well supported, however participants suggested that non-compliance was a concern. Although, the SPR remained above the 40% target reference point, further declines in the stock status should be prevented through the implementation of a 600-850 mm TL harvest slot limit. Based on the findings of this study, this limit should provide protection against both growth and recruitment overfishing by providing protection to sexually immature, fast growing fish and to large adults that contribute the greatest proportion to population replenishment.
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BODIPY dyes for application in the photo-oxidation of pollutants, photodynamic antimicrobial chemotherapy, and nonlinear optics
- Authors: Kelechi, Lebechi Augustus
- Date: 2020
- Subjects: Dyes and dyeing -- Chemistry , Fluorescent probes , Fluorescence spectroscopy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/140298 , vital:37859
- Description: The synthesis and structural characterization of a series of BODIPY dyes to analyze both the effects of halogenations at the 2,6-positions and the introduction of styryl groups at the 3,5-positions. The photophysical properties of these dyes were investigated to determine their suitability as singlet oxygen-generating photosensitiser dyes for application in photocatalytic degradation of azo dyes and in photodynamic antimicrobial chemotherapy (PACT). Upon halogenation, the dyes showed high to moderate singlet oxygen quantum yields. The potential utility of electrospun polystyrene (PS) nanofibres embedded with halogenated BODIPY dyes for the photocatalytic degradation of Orange G and Methyl Orange from textile industry effluents were investigated. A comparison of the singlet oxygen quantum yield of the BODIPY dyes in solution and when embedded in the PS nanofibres support demonstrates that its photosensitiser properties are maintained in the nanofibre mats. The photocatalytic degradation properties of the PS nanofibres for Orange G and Methyl Orange were determined by using a 530 nm and 660 nm light-emitting diodes. The rate of photodegradation increases with both the Orange G and Methyl Orange concentrations and follows pseudo-first-order kinetics. The PACT activities of brominated BODIPYs on Escherichia coli and Staphylococcus aureus were investigated. Log reduction values of over 9 were obtained during the photoinactivation of Staphylococcus aureus. To be able to red-shift the main spectral band of the BODIPY dyes into the therapeutic window, styryl groups were introduced at the 3,5-positions through a modified Knoevenagel condensation reaction. Because the red-shifted spectral band lies above 532 nm, the second harmonic of the Nd:YAG laser, there is very minute absorption at this wavelength. One of the novel brominated BODIPY dyes was investigated for its potential utility as optical limiting materials in nonlinear optics (NLO), and the dyes demonstrated typical nonlinear absorption behaviour characterised by reverse saturable absorption (RSA) in Z-scan measurements. Excellent optical limiting parameters were obtained for third-order susceptibility and hyperpolarisability.
- Full Text:
- Authors: Kelechi, Lebechi Augustus
- Date: 2020
- Subjects: Dyes and dyeing -- Chemistry , Fluorescent probes , Fluorescence spectroscopy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/140298 , vital:37859
- Description: The synthesis and structural characterization of a series of BODIPY dyes to analyze both the effects of halogenations at the 2,6-positions and the introduction of styryl groups at the 3,5-positions. The photophysical properties of these dyes were investigated to determine their suitability as singlet oxygen-generating photosensitiser dyes for application in photocatalytic degradation of azo dyes and in photodynamic antimicrobial chemotherapy (PACT). Upon halogenation, the dyes showed high to moderate singlet oxygen quantum yields. The potential utility of electrospun polystyrene (PS) nanofibres embedded with halogenated BODIPY dyes for the photocatalytic degradation of Orange G and Methyl Orange from textile industry effluents were investigated. A comparison of the singlet oxygen quantum yield of the BODIPY dyes in solution and when embedded in the PS nanofibres support demonstrates that its photosensitiser properties are maintained in the nanofibre mats. The photocatalytic degradation properties of the PS nanofibres for Orange G and Methyl Orange were determined by using a 530 nm and 660 nm light-emitting diodes. The rate of photodegradation increases with both the Orange G and Methyl Orange concentrations and follows pseudo-first-order kinetics. The PACT activities of brominated BODIPYs on Escherichia coli and Staphylococcus aureus were investigated. Log reduction values of over 9 were obtained during the photoinactivation of Staphylococcus aureus. To be able to red-shift the main spectral band of the BODIPY dyes into the therapeutic window, styryl groups were introduced at the 3,5-positions through a modified Knoevenagel condensation reaction. Because the red-shifted spectral band lies above 532 nm, the second harmonic of the Nd:YAG laser, there is very minute absorption at this wavelength. One of the novel brominated BODIPY dyes was investigated for its potential utility as optical limiting materials in nonlinear optics (NLO), and the dyes demonstrated typical nonlinear absorption behaviour characterised by reverse saturable absorption (RSA) in Z-scan measurements. Excellent optical limiting parameters were obtained for third-order susceptibility and hyperpolarisability.
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BODIPY dyes for use in nonlinear optics and optical sensing
- Authors: Kubheka, Gugu Patience
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163352 , vital:41032 , doi:10.21504/10962/163352
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Department of Chemistry, 2020.
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- Authors: Kubheka, Gugu Patience
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163352 , vital:41032 , doi:10.21504/10962/163352
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Department of Chemistry, 2020.
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Budget Deficits, the Savings Gap and Current Account Deficits in the Southern African Development Community
- Authors: Kopeledi, Alyssa
- Date: 2020
- Subjects: Budget deficits -- South Africa , Accounts current
- Language: English
- Type: Thesis , Masters , MCom (Economics)
- Identifier: http://hdl.handle.net/10353/12392 , vital:39259
- Description: This study examines the validity of the triple deficit hypothesis for a selected number of SADC countries, utilising secondary annual data for the period 1996-2018. Based on previous studies and theory, current account deficit was chosen as the dependent variable and budget deficit and the savings gap as the independent variables. The study makes use of both first generation and second-generation unit root tests to examine the time series properties of the data. The empirical results show that the data is integrated of different orders. Kao, Pedroni and Westerlund cointegration tests were carried out to examine the long-term relationship between the variables of interest. The empirical results revealed that there is a long-term relationship between current account deficit, budget deficit s and the savings gap. The long-run model under the Autoregressive Distributed Lag test revealed that, a positive and significant relationship exists between budget deficit and current account deficit at a significance level of 10% and a negative and insignificant relationship exists between savings gap and current account deficit in the long run. This suggests that an improvement in the current account balance in SADC countries requires fiscal stringency
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- Authors: Kopeledi, Alyssa
- Date: 2020
- Subjects: Budget deficits -- South Africa , Accounts current
- Language: English
- Type: Thesis , Masters , MCom (Economics)
- Identifier: http://hdl.handle.net/10353/12392 , vital:39259
- Description: This study examines the validity of the triple deficit hypothesis for a selected number of SADC countries, utilising secondary annual data for the period 1996-2018. Based on previous studies and theory, current account deficit was chosen as the dependent variable and budget deficit and the savings gap as the independent variables. The study makes use of both first generation and second-generation unit root tests to examine the time series properties of the data. The empirical results show that the data is integrated of different orders. Kao, Pedroni and Westerlund cointegration tests were carried out to examine the long-term relationship between the variables of interest. The empirical results revealed that there is a long-term relationship between current account deficit, budget deficit s and the savings gap. The long-run model under the Autoregressive Distributed Lag test revealed that, a positive and significant relationship exists between budget deficit and current account deficit at a significance level of 10% and a negative and insignificant relationship exists between savings gap and current account deficit in the long run. This suggests that an improvement in the current account balance in SADC countries requires fiscal stringency
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Building a flexible and inexpensive multi-layer switch for software-defined networks
- Authors: Magwenzi, Tinashe
- Date: 2020
- Subjects: Software-defined networking (Computer network technology) , Telecommunication -- Switching systems , OpenFlow (Computer network protocol) , Local area networks (Computer networks)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/142841 , vital:38122
- Description: Software-Defined Networking (SDN) is a paradigm which enables the realisation of programmable network through the separation of the control logic from the forwarding functions. This separation is a departure from the traditional architecture. Much of the work done in SDN enabled devices has concentrated on higher end, high speed networks (10s GBit/s 100s GBit/s), rather than the relatively low bandwidth links (10s MBit/s to a few GBit/s) which are seen, for example, in South Africa. As SDN is increasingly becoming more accepted, due to its advantages over the traditional networks, it has been adopted for industrial purposes such as networking in data centres and network providers. The demand for programmable networks is increasing but is limited by the ability of providers to upgrade their infrastructure. In addition, as access to the Internet has become less expensive, the use of Internet is increasing in academic institutions, NGOs, and small to medium enterprises. This thesis details a means of building and managing a small scale Software-Defined Network using commodity hardware and open source tools. Core to the SDN Network illustrated in this thesis is the prototype of a multi-layer SDN switch. The proposed device is targeted to serve lower bandwidth communication (in relation to commercially produced high speed SDN-enabled devices). The performance of the prototype multilayer switch had shown to achieve: data-rates of up to 99.998%, average latencies that are under 40µs during forwarding/switching and under 100µs during routing while using packet sizes between 64 bytes and 1518 bytes, and a jitter of less than 15µs during all tests. This research explores in detail the design, development, and management of a multi-layer switch and its placement and integration in small scale SDN network. This includes testing of Layer 2 forwarding and Layer 3 routing, OpenFlow compliance testing, the management of the switch using created SDN applications, and real life network functionality such as forwarding, routing and VLAN networking to demonstrate its real world applicability.
- Full Text:
- Authors: Magwenzi, Tinashe
- Date: 2020
- Subjects: Software-defined networking (Computer network technology) , Telecommunication -- Switching systems , OpenFlow (Computer network protocol) , Local area networks (Computer networks)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/142841 , vital:38122
- Description: Software-Defined Networking (SDN) is a paradigm which enables the realisation of programmable network through the separation of the control logic from the forwarding functions. This separation is a departure from the traditional architecture. Much of the work done in SDN enabled devices has concentrated on higher end, high speed networks (10s GBit/s 100s GBit/s), rather than the relatively low bandwidth links (10s MBit/s to a few GBit/s) which are seen, for example, in South Africa. As SDN is increasingly becoming more accepted, due to its advantages over the traditional networks, it has been adopted for industrial purposes such as networking in data centres and network providers. The demand for programmable networks is increasing but is limited by the ability of providers to upgrade their infrastructure. In addition, as access to the Internet has become less expensive, the use of Internet is increasing in academic institutions, NGOs, and small to medium enterprises. This thesis details a means of building and managing a small scale Software-Defined Network using commodity hardware and open source tools. Core to the SDN Network illustrated in this thesis is the prototype of a multi-layer SDN switch. The proposed device is targeted to serve lower bandwidth communication (in relation to commercially produced high speed SDN-enabled devices). The performance of the prototype multilayer switch had shown to achieve: data-rates of up to 99.998%, average latencies that are under 40µs during forwarding/switching and under 100µs during routing while using packet sizes between 64 bytes and 1518 bytes, and a jitter of less than 15µs during all tests. This research explores in detail the design, development, and management of a multi-layer switch and its placement and integration in small scale SDN network. This includes testing of Layer 2 forwarding and Layer 3 routing, OpenFlow compliance testing, the management of the switch using created SDN applications, and real life network functionality such as forwarding, routing and VLAN networking to demonstrate its real world applicability.
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Can fishing tourism contribute to conservation and sustainability via ecotourism?: a case study of the Fishery for Giant African Threadfin Polydactylus quadrifilis on the Kwanza Estuary, Angola
- Butler, Edward C, Childs, Amber-Robyn, Saayman, Andrea, Potts, Warren M
- Authors: Butler, Edward C , Childs, Amber-Robyn , Saayman, Andrea , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149253 , vital:38819 , https://doi.org/10.3390/su12104221
- Description: It has been suggested that tourism fisheries can raise the value of landed catch, provide alternative livelihoods for local artisanal fishers and, because recreationally caught fishes are often released, simultaneously conserve stocks. However, for fishing tourism to meet ecotourism standards, sustainable, local economic benefit is imperative. This study aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary, Angola. The recreational fishery contributed significantly to economic productivity in an otherwise rural area, generating a total revenue (TR) of $236,826 per four-month fishing season.
- Full Text:
- Authors: Butler, Edward C , Childs, Amber-Robyn , Saayman, Andrea , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149253 , vital:38819 , https://doi.org/10.3390/su12104221
- Description: It has been suggested that tourism fisheries can raise the value of landed catch, provide alternative livelihoods for local artisanal fishers and, because recreationally caught fishes are often released, simultaneously conserve stocks. However, for fishing tourism to meet ecotourism standards, sustainable, local economic benefit is imperative. This study aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary, Angola. The recreational fishery contributed significantly to economic productivity in an otherwise rural area, generating a total revenue (TR) of $236,826 per four-month fishing season.
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Carbon isotope evidence for water-column carbon and iron cycling in the Paleoproterozoic ocean and implications for the early biological pump: supplementary data file
- Tsikos, Harilaos, Rafuza, Sipesihle, Mhlanga, Zolane R, Oonk, Paul B H, Papadopoulos, Vlassis, Boyce, Adrian C, Mason, Paul R D, Harris, Christopher, Gröcke, Darren R, Lyons, Timothy W
- Authors: Tsikos, Harilaos , Rafuza, Sipesihle , Mhlanga, Zolane R , Oonk, Paul B H , Papadopoulos, Vlassis , Boyce, Adrian C , Mason, Paul R D , Harris, Christopher , Gröcke, Darren R , Lyons, Timothy W
- Date: 2020
- Subjects: Carbon isotypes , Paeloproterozoic ocean , Water-column carbon , Iron cycling
- Language: English
- Type: Data set
- Identifier: http://hdl.handle.net/10962/138395 , vital:37632 , http://dx.doi.org/10.21504/10962/138395
- Description: Supplemantary data file: Carbon isotope evidence for water-column carbon and iron cycling in the Paleoproterozoic ocean and implications for the early biological pump.
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- Authors: Tsikos, Harilaos , Rafuza, Sipesihle , Mhlanga, Zolane R , Oonk, Paul B H , Papadopoulos, Vlassis , Boyce, Adrian C , Mason, Paul R D , Harris, Christopher , Gröcke, Darren R , Lyons, Timothy W
- Date: 2020
- Subjects: Carbon isotypes , Paeloproterozoic ocean , Water-column carbon , Iron cycling
- Language: English
- Type: Data set
- Identifier: http://hdl.handle.net/10962/138395 , vital:37632 , http://dx.doi.org/10.21504/10962/138395
- Description: Supplemantary data file: Carbon isotope evidence for water-column carbon and iron cycling in the Paleoproterozoic ocean and implications for the early biological pump.
- Full Text: