Post release evaluation of the distribution and efficacy of Eccritotarsus catarinensis and Eccritotarsus eichhorniae on Pontederia crassipes in South Africa
- Authors: Maseko, Zolile
- Date: 2020
- Subjects: Water hyacinth -- Biological control -- South Africa , Weeds -- Biological control -- South Africa , Miridae -- South Africa , Insects as biological pest control agents -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143046 , vital:38196
- Description: Biological control involves the release of new species into the environment and therefore, needs to be carefully monitored through post-release assessments which have been largely neglected in the science. Post-release evaluations of biological control programmes reveal whether the control agent has established and if it impacts weed demography, while cost-benefit analyses require a different set of data that show the magnitude on return on investment. The biological control effort on Pontederia crassipes in South Africa uses, amongst others, two species of mirid, Eccritotarsus catarinensis and E. eichhorniae. Initially, they were released as a single species, but were recently divided using molecular techniques. Eccritotarsus catarinensis was released in 1999, and E. eichhorniae in 2007. After many releases over two decades, there was need to assess where each species was established in the country. Molecular techniques proved to be valuable in identifying the two species as they are morphologically indistinguishable in the field. Therefore, molecular techniques should be routinely used for screening biocontrol agents, whether new or as re-introductions. Annual surveys of the mirid release sites around South Africa were undertaken between 2016 and 2019. At each site both insect and plant parameters were measured. Only E. catarinensis is established in the field in South Africa despite the multiple releases of E. eichhorniae at over 70 sites across the country, and E. catarinensis has established at only 22 of the 45 release sites accessed during this study. This thesis tested climate, interaction with other agents already on P. crassipes, and direct competition between the two mirid species as reasons for the lack of establishment of E. eichhorniae. The results of the country-wide surveys showed that climate and water trophic status were the major determinants in the establishment of E. catarinensis. Most of the establishment was recorded in the warmer regions of the country, however, a few populations of the mirid also established in cooler areas, thus demonstrating a degree of thermal plasticity, and possible microclimates as the mirids persisted at sites shaded by riparian vegetation. Stochastic events such as active herbicide campaigns, winter frosts, droughts and floods were responsible for the absence of the mirid at some sites. At some of the eutrophic sites, despite the abundance of E. catarinensis, plants still proliferated as the water trophic status facilitated plant growth, thus, plants were able to compensate for the damage inflicted by the mirid. A more intensive, monthly, post-release evaluation was conducted on the Kubusi River, Eastern Cape Province between 2016 and 2019. This is regarded as one of the cooler water hyacinth sites. Populations of biological control agents at this site fluctuated seasonally. At this site, cold winters caused frosting of the leaves of P. crassipes with the exception of plants growing under overhanging vegetation that provided a refuge for the mirid. But, cool temperatures in the winter months (May to August) severely reduced the populations of E. catarinensis that required a long recovery phase in spring. The consequence of this was that the plants grew unchecked from the onset of the growing season forming dense mats. Of the four agents at the Kubusi River site, Eccritotarsus catarinensis recovered slowest after winter, with lag phases ranging from two months to several months of the three-year period. The release of a suite of agents has implications on the agents themselves, where interactions between the agents can be important. Interactions between pairs and even multiple agents can have implications for biocontrol, where agents are either complimentary or interfere with each other. In this case, because E. catarinensis recovered the slowest of the four agents at the site, plants were of a poor quality by mid-summer resulting in low mirid populations. Competition in weed biological control could be expected to be strongest between pairs of agents that share the same niche, and this could be the reason why E. eichhorniae failed to establish at sites where E. catarinensis had already been established for several years. When the two mirids were combined in manipulated trials in a polytunnel, populations were lower compared to when the two mirids occurred separately. Under warm conditions, it is likely that E. eichhorniae would be the superior agent compared to E. catarinensis. The evaluations discussed in this thesis highlighted gaps in agent release methodology in multispecies settings, as well as the need for strategic augmentation pre- and post-winter. It is important to release agents that will complement each other rather than compete, therefore, when releasing agents in a multispecies setting, niche differentiation needs to be considered. Here it is concluded that the best practice for dealing with the mirids is that they should be released individually, and at sites that have no other biological control agents in order to ultimately assess their efficacy. Landscape level, long-term monitoring of biological control programmes shows the impact of the control programme at a broader scale and, are far more informative than short-term studies and at fewer sites. Long-term post-release evaluations should be mandatory in biological control programmes. Furthermore, these assessments will help develop new strategies or improve on existing ones, thus achieve greater success in control.
- Full Text:
- Date Issued: 2020
- Authors: Maseko, Zolile
- Date: 2020
- Subjects: Water hyacinth -- Biological control -- South Africa , Weeds -- Biological control -- South Africa , Miridae -- South Africa , Insects as biological pest control agents -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143046 , vital:38196
- Description: Biological control involves the release of new species into the environment and therefore, needs to be carefully monitored through post-release assessments which have been largely neglected in the science. Post-release evaluations of biological control programmes reveal whether the control agent has established and if it impacts weed demography, while cost-benefit analyses require a different set of data that show the magnitude on return on investment. The biological control effort on Pontederia crassipes in South Africa uses, amongst others, two species of mirid, Eccritotarsus catarinensis and E. eichhorniae. Initially, they were released as a single species, but were recently divided using molecular techniques. Eccritotarsus catarinensis was released in 1999, and E. eichhorniae in 2007. After many releases over two decades, there was need to assess where each species was established in the country. Molecular techniques proved to be valuable in identifying the two species as they are morphologically indistinguishable in the field. Therefore, molecular techniques should be routinely used for screening biocontrol agents, whether new or as re-introductions. Annual surveys of the mirid release sites around South Africa were undertaken between 2016 and 2019. At each site both insect and plant parameters were measured. Only E. catarinensis is established in the field in South Africa despite the multiple releases of E. eichhorniae at over 70 sites across the country, and E. catarinensis has established at only 22 of the 45 release sites accessed during this study. This thesis tested climate, interaction with other agents already on P. crassipes, and direct competition between the two mirid species as reasons for the lack of establishment of E. eichhorniae. The results of the country-wide surveys showed that climate and water trophic status were the major determinants in the establishment of E. catarinensis. Most of the establishment was recorded in the warmer regions of the country, however, a few populations of the mirid also established in cooler areas, thus demonstrating a degree of thermal plasticity, and possible microclimates as the mirids persisted at sites shaded by riparian vegetation. Stochastic events such as active herbicide campaigns, winter frosts, droughts and floods were responsible for the absence of the mirid at some sites. At some of the eutrophic sites, despite the abundance of E. catarinensis, plants still proliferated as the water trophic status facilitated plant growth, thus, plants were able to compensate for the damage inflicted by the mirid. A more intensive, monthly, post-release evaluation was conducted on the Kubusi River, Eastern Cape Province between 2016 and 2019. This is regarded as one of the cooler water hyacinth sites. Populations of biological control agents at this site fluctuated seasonally. At this site, cold winters caused frosting of the leaves of P. crassipes with the exception of plants growing under overhanging vegetation that provided a refuge for the mirid. But, cool temperatures in the winter months (May to August) severely reduced the populations of E. catarinensis that required a long recovery phase in spring. The consequence of this was that the plants grew unchecked from the onset of the growing season forming dense mats. Of the four agents at the Kubusi River site, Eccritotarsus catarinensis recovered slowest after winter, with lag phases ranging from two months to several months of the three-year period. The release of a suite of agents has implications on the agents themselves, where interactions between the agents can be important. Interactions between pairs and even multiple agents can have implications for biocontrol, where agents are either complimentary or interfere with each other. In this case, because E. catarinensis recovered the slowest of the four agents at the site, plants were of a poor quality by mid-summer resulting in low mirid populations. Competition in weed biological control could be expected to be strongest between pairs of agents that share the same niche, and this could be the reason why E. eichhorniae failed to establish at sites where E. catarinensis had already been established for several years. When the two mirids were combined in manipulated trials in a polytunnel, populations were lower compared to when the two mirids occurred separately. Under warm conditions, it is likely that E. eichhorniae would be the superior agent compared to E. catarinensis. The evaluations discussed in this thesis highlighted gaps in agent release methodology in multispecies settings, as well as the need for strategic augmentation pre- and post-winter. It is important to release agents that will complement each other rather than compete, therefore, when releasing agents in a multispecies setting, niche differentiation needs to be considered. Here it is concluded that the best practice for dealing with the mirids is that they should be released individually, and at sites that have no other biological control agents in order to ultimately assess their efficacy. Landscape level, long-term monitoring of biological control programmes shows the impact of the control programme at a broader scale and, are far more informative than short-term studies and at fewer sites. Long-term post-release evaluations should be mandatory in biological control programmes. Furthermore, these assessments will help develop new strategies or improve on existing ones, thus achieve greater success in control.
- Full Text:
- Date Issued: 2020
Metallophthalocyanines linked to metal nanoparticles and folic acid for use in photodynamic therapy of cancer and photoinactivation of bacterial microorganisms.
- Authors: Matlou, Gauta Gold
- Date: 2020
- Subjects: Cancer -- Photochemotherapy , Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166540 , vital:41377
- Description: This thesis presents on the synthesis and characterization of novel asymmetric and symmetrical metallophthalocyanines (MPcs) substituted with carboxylic acid functional groups and centrally metallated with zinc and indium. The MPcs are further covalently linked to cysteine capped silver nanoparticles (cys-AgNPs), amino functionalized magnetic nanoparticles (AMNPs) and folic acid (FA) through an amide bond between the carboxylic group of MPcs and the amino group of FA, cys-AgNPs or AMNPs. The covalent linkage of MPcs to FA improved the water solubility of MPcs and allowed for singlet oxygen quantum yield determination in water. Asymmetric MPcs and their conjugates were found to have improved photochemical and photophysical properties compared to symmetrical MPcs and their conjugates. The heavy atom effect of AMNPs and AgNPs improved the triplet and singlet oxygen quantum yields of MPcs. MPcs and their conjugates (MPc-FA, MPc-AMNPs, MPc-AgNPs) were found to have lower in vitro dark cytotoxicity and higher photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. The water soluble MPc-FA had better PDT activity when compared to MPc-AMNPs due to the active targeting of folic acid-folate binding on cancer cell surface. MPcs and MPc-AgNPs conjugates also showed excellent in vitro cytotoxicity on S. aureus under light irradiation compared to dark cytotoxicity. The photosensitizing properties of MPcs and their conjugates are demonstrated for the first time in this thesis, both on breast cancer cells (MCF-7) through photodynamic therapy and on microorganisms (S. aureus) through photodynamic antimicrobial chemotherapy.
- Full Text:
- Date Issued: 2020
- Authors: Matlou, Gauta Gold
- Date: 2020
- Subjects: Cancer -- Photochemotherapy , Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166540 , vital:41377
- Description: This thesis presents on the synthesis and characterization of novel asymmetric and symmetrical metallophthalocyanines (MPcs) substituted with carboxylic acid functional groups and centrally metallated with zinc and indium. The MPcs are further covalently linked to cysteine capped silver nanoparticles (cys-AgNPs), amino functionalized magnetic nanoparticles (AMNPs) and folic acid (FA) through an amide bond between the carboxylic group of MPcs and the amino group of FA, cys-AgNPs or AMNPs. The covalent linkage of MPcs to FA improved the water solubility of MPcs and allowed for singlet oxygen quantum yield determination in water. Asymmetric MPcs and their conjugates were found to have improved photochemical and photophysical properties compared to symmetrical MPcs and their conjugates. The heavy atom effect of AMNPs and AgNPs improved the triplet and singlet oxygen quantum yields of MPcs. MPcs and their conjugates (MPc-FA, MPc-AMNPs, MPc-AgNPs) were found to have lower in vitro dark cytotoxicity and higher photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. The water soluble MPc-FA had better PDT activity when compared to MPc-AMNPs due to the active targeting of folic acid-folate binding on cancer cell surface. MPcs and MPc-AgNPs conjugates also showed excellent in vitro cytotoxicity on S. aureus under light irradiation compared to dark cytotoxicity. The photosensitizing properties of MPcs and their conjugates are demonstrated for the first time in this thesis, both on breast cancer cells (MCF-7) through photodynamic therapy and on microorganisms (S. aureus) through photodynamic antimicrobial chemotherapy.
- Full Text:
- Date Issued: 2020
An analysis of how leadership has shaped the culture of customer centricity in the branch of a bank
- Authors: Mali, Mandisa
- Date: 2020
- Subjects: Banks and banking -- Customer services , Banks and banking -- Customer services -- South Africa -- Case studies , Customer relations -- Management , Customer relations -- Management -- South Africa -- Case studies , Relationship banking -- South Africa -- Case studies , Bank management -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/171852 , vital:42132
- Description: Financial institutions are faced with increasing competition as there has been an increase in new entrants in the industry, therefore a battle of market share in banking is in progress. Digitization is fast changing how customers perceive value, customers have become spoilt for choice and thus banks have to implement strategies that will help them to increase their market share by keeping the customers they currently have and strategies that help them to acquire more customers. A strategy on its own will not support organizational goals, if it is not adopted by the executers – the employees on the ground. It is important for leaders to support the strategic goals of an organization by ensuring that the goals become a culture, a way of doing things in that organization. This study is an analysis of how leadership shaped a culture of customer centricity in the branch of a bank. The objectives of the study were to: (1) To describe the culture of customer centricity that was cultivated by the branch manager; (2) To analyse what the leader pays attention to, measures and controls on a regular basis, in support of a culture of customer centricity; (3) To analyse how the leader conducts deliberate role modelling, teaching and coaching in support of a culture of customer centricity; (4) To analyse whether - and if so how - the quality of the dyadic relations between the leader and her followers enables or disables the effect of cultural mechanisms on the culture of customer centricity; and (5) To analyse how the leader built high quality relations with her followers The study took the form of a case study of a branch of a bank, where nine universal bankers and their former leader were interviewed. The data were then analysed using a deductive thematic analysis. The findings met all objectives of the study and the findings supported the propositions. The findings also discovered that reward and recognition contributed to the shaping of a culture of customer centricity. In conclusion the limitations and delimitations of the study are acknowledged, and recommendations are made. The study contributes towards the Social Exchange Theory (SET) and demonstrates how high-quality leader member exchange (LMX) relations can be developed. Several recommendations are made for further studies on factors shaping a culture of customer centricity, and implications for management are considered.
- Full Text:
- Date Issued: 2020
- Authors: Mali, Mandisa
- Date: 2020
- Subjects: Banks and banking -- Customer services , Banks and banking -- Customer services -- South Africa -- Case studies , Customer relations -- Management , Customer relations -- Management -- South Africa -- Case studies , Relationship banking -- South Africa -- Case studies , Bank management -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/171852 , vital:42132
- Description: Financial institutions are faced with increasing competition as there has been an increase in new entrants in the industry, therefore a battle of market share in banking is in progress. Digitization is fast changing how customers perceive value, customers have become spoilt for choice and thus banks have to implement strategies that will help them to increase their market share by keeping the customers they currently have and strategies that help them to acquire more customers. A strategy on its own will not support organizational goals, if it is not adopted by the executers – the employees on the ground. It is important for leaders to support the strategic goals of an organization by ensuring that the goals become a culture, a way of doing things in that organization. This study is an analysis of how leadership shaped a culture of customer centricity in the branch of a bank. The objectives of the study were to: (1) To describe the culture of customer centricity that was cultivated by the branch manager; (2) To analyse what the leader pays attention to, measures and controls on a regular basis, in support of a culture of customer centricity; (3) To analyse how the leader conducts deliberate role modelling, teaching and coaching in support of a culture of customer centricity; (4) To analyse whether - and if so how - the quality of the dyadic relations between the leader and her followers enables or disables the effect of cultural mechanisms on the culture of customer centricity; and (5) To analyse how the leader built high quality relations with her followers The study took the form of a case study of a branch of a bank, where nine universal bankers and their former leader were interviewed. The data were then analysed using a deductive thematic analysis. The findings met all objectives of the study and the findings supported the propositions. The findings also discovered that reward and recognition contributed to the shaping of a culture of customer centricity. In conclusion the limitations and delimitations of the study are acknowledged, and recommendations are made. The study contributes towards the Social Exchange Theory (SET) and demonstrates how high-quality leader member exchange (LMX) relations can be developed. Several recommendations are made for further studies on factors shaping a culture of customer centricity, and implications for management are considered.
- Full Text:
- Date Issued: 2020
Design ethnography: methodological considerations for rebalancing socio-technical phenomena in CMS performativity
- Authors: Jordaan, Leandra
- Date: 2020
- Subjects: Database management -- Social aspects , Information technology -- Social aspects , Management information systems -- Social aspects , Database management -- Philosophy , Information technology -- Philosophy , Management information systems -- Philosophy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164781 , vital:41164
- Description: As a practitioner, I had been part of two Content Management System (CMS) Projects in a particular setting that did not deliver on the expected outcomes. The expected outcomes of the projects included streamlined processes, better access to information, functionalities to drive engagement, reduced time searching for information, and improved reusability of content. As I began to reflect on the projects, a certain discomfort developed when the social aspect was ignored in favour of the technological. I sought a better understanding, but I was unaware of the fact at first. The techno-centricity as a concept found in literature and my experience as content management (CM) practitioner – together informed my interest in rebalancing the social and the technological. Thus, I focused on conduct in performing of tasks and emphasised attention on the practices of experts who gave insight into context of CM and use. The research participants are communication practitioners who have the responsibility to communicate internally and externally on behalf of a publicly-funded university in South Africa. Guided by the abductive argument and literature, the key themes for the research focused on technology, individuals and the organisation. The focus on technology (CMS as a subfield of Information Systems) began with my involvement in two CMS Projects. What came to the fore was that the practitioner perspective, and thus their experiential knowledge are neglected in research and that it may be an over-emphasis on techno-centrism in CMS research. I sought to better balance the social and technological aspects. The second focus on individuals (communication practitioners) was to value the stakeholder who was considered representative of the worldviews of the community. I sought to support corporate communication practices in the task of relationship building with stakeholders. The findings showed that the culture of informatio sharing was low at the University. The third focus on the organisation (the University) was to prioritise the success of the communication undertaken by the University. I interrogated the role of power. I demonstrated how the role of power could be seen as productive and positive in the context of HE, the social reality of CUT, and this IS research itself. I positioned the research as interpretivistic. I used hermeneutics as a mode of analysis because as researcher-practitioner, I am part of the social reality of the research. A safeguard against my subjectivity was the use of Phronesis as an orientation to knowledge. An organisation with a shared understanding of ethics and values will balance instrumental rationality (scientific and technical reasoning) with value-rationality (moral reasoning about right and wrong actions). Phronesis is the virtue that should ensure ethical behaviour in actions, yet over time, social science research, in a quest to mimic the natural sciences, centred on episteme and techne. I constructed the lens by particularising the four value-rational questions of Flyvbjerg’s contemporary Phronesis to the performative perspective of the research. My interest in social reality, as well as socio-technical aspects, have led to design-ethnography (D-E) to emerge as the most suitable and most appropriate approach to the research. D-E asked the prescriptive ‘How’ and descriptive ‘What’ questions, whilst the Flyvbjergian Phronesis lens brought focus on the ‘Why’ question. D-E emphasised the betterment of the interaction and synergy between research conducted and practice. My status as an immersed researcher needed careful consideration, and D-E accepted that a certain level of immersion is necessary, D-E has short interventional fieldwork, and D-E has future-oriented engagement. The contemporary Phronesis used in the research is to enact D-E and not an all-encompassing guide for doing Phronesis research The key contributions to the research are predominantly methodological. The claims draw on evidence focused on the three themes technology, individuals and organisation, and the phenomena of interest which are to rebalance the social and the technological in CM practices. The first claim is that immersion in the context is possible and supported by the specific particularised approaches to the research. The second claim suggests a way to rebalance the socio-technical nature of Information Systems (IS). The third claim suggests that there is a viewpoint for power that is not focused on power’s oppressive nature which could see a diverging focus on power in IS research in future. In this viewpoint, the status quo of social reality is not questioned, nor are their emancipatory ambitions. The fourth and final claim suggests that Phronesis as a lens could enact D-E, which in turn is a method that assists in valuing the experience of the practitioner and the support of collaborative work. The research is recommended for IT/IS practitioners who prefer to value participants’ views in design. The approaches used could be of value for researchers who consider the context of their research to be of higher importance than the generalisation of outcomes. Researchers who find themselves in the position of being immersed in the context but question the correctness of active engagement in the field may discover some value from the research approaches and my experience. Also, researchers or practitioners who have an interest in the balance between social and the technological aspects of IS projects. Researchers or practitioners interested in Phronesis, and perhaps the viewpoint of a lens may also find value in this research.
- Full Text:
- Date Issued: 2020
- Authors: Jordaan, Leandra
- Date: 2020
- Subjects: Database management -- Social aspects , Information technology -- Social aspects , Management information systems -- Social aspects , Database management -- Philosophy , Information technology -- Philosophy , Management information systems -- Philosophy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164781 , vital:41164
- Description: As a practitioner, I had been part of two Content Management System (CMS) Projects in a particular setting that did not deliver on the expected outcomes. The expected outcomes of the projects included streamlined processes, better access to information, functionalities to drive engagement, reduced time searching for information, and improved reusability of content. As I began to reflect on the projects, a certain discomfort developed when the social aspect was ignored in favour of the technological. I sought a better understanding, but I was unaware of the fact at first. The techno-centricity as a concept found in literature and my experience as content management (CM) practitioner – together informed my interest in rebalancing the social and the technological. Thus, I focused on conduct in performing of tasks and emphasised attention on the practices of experts who gave insight into context of CM and use. The research participants are communication practitioners who have the responsibility to communicate internally and externally on behalf of a publicly-funded university in South Africa. Guided by the abductive argument and literature, the key themes for the research focused on technology, individuals and the organisation. The focus on technology (CMS as a subfield of Information Systems) began with my involvement in two CMS Projects. What came to the fore was that the practitioner perspective, and thus their experiential knowledge are neglected in research and that it may be an over-emphasis on techno-centrism in CMS research. I sought to better balance the social and technological aspects. The second focus on individuals (communication practitioners) was to value the stakeholder who was considered representative of the worldviews of the community. I sought to support corporate communication practices in the task of relationship building with stakeholders. The findings showed that the culture of informatio sharing was low at the University. The third focus on the organisation (the University) was to prioritise the success of the communication undertaken by the University. I interrogated the role of power. I demonstrated how the role of power could be seen as productive and positive in the context of HE, the social reality of CUT, and this IS research itself. I positioned the research as interpretivistic. I used hermeneutics as a mode of analysis because as researcher-practitioner, I am part of the social reality of the research. A safeguard against my subjectivity was the use of Phronesis as an orientation to knowledge. An organisation with a shared understanding of ethics and values will balance instrumental rationality (scientific and technical reasoning) with value-rationality (moral reasoning about right and wrong actions). Phronesis is the virtue that should ensure ethical behaviour in actions, yet over time, social science research, in a quest to mimic the natural sciences, centred on episteme and techne. I constructed the lens by particularising the four value-rational questions of Flyvbjerg’s contemporary Phronesis to the performative perspective of the research. My interest in social reality, as well as socio-technical aspects, have led to design-ethnography (D-E) to emerge as the most suitable and most appropriate approach to the research. D-E asked the prescriptive ‘How’ and descriptive ‘What’ questions, whilst the Flyvbjergian Phronesis lens brought focus on the ‘Why’ question. D-E emphasised the betterment of the interaction and synergy between research conducted and practice. My status as an immersed researcher needed careful consideration, and D-E accepted that a certain level of immersion is necessary, D-E has short interventional fieldwork, and D-E has future-oriented engagement. The contemporary Phronesis used in the research is to enact D-E and not an all-encompassing guide for doing Phronesis research The key contributions to the research are predominantly methodological. The claims draw on evidence focused on the three themes technology, individuals and organisation, and the phenomena of interest which are to rebalance the social and the technological in CM practices. The first claim is that immersion in the context is possible and supported by the specific particularised approaches to the research. The second claim suggests a way to rebalance the socio-technical nature of Information Systems (IS). The third claim suggests that there is a viewpoint for power that is not focused on power’s oppressive nature which could see a diverging focus on power in IS research in future. In this viewpoint, the status quo of social reality is not questioned, nor are their emancipatory ambitions. The fourth and final claim suggests that Phronesis as a lens could enact D-E, which in turn is a method that assists in valuing the experience of the practitioner and the support of collaborative work. The research is recommended for IT/IS practitioners who prefer to value participants’ views in design. The approaches used could be of value for researchers who consider the context of their research to be of higher importance than the generalisation of outcomes. Researchers who find themselves in the position of being immersed in the context but question the correctness of active engagement in the field may discover some value from the research approaches and my experience. Also, researchers or practitioners who have an interest in the balance between social and the technological aspects of IS projects. Researchers or practitioners interested in Phronesis, and perhaps the viewpoint of a lens may also find value in this research.
- Full Text:
- Date Issued: 2020
A reappraisal of the origin of the Hotazel Fe-Mn Formation in an evolving early Earth system through the application of mineral-specific geochemistry, speciation techniques and stable isotope systematics
- Authors: Mhlanga, Xolane Reginald
- Date: 2020
- Subjects: Manganese ores -- South Africa -- Hotazel , Manganese ores -- Geology , Iron ores -- South Africa -- Hotazel , Iron ores -- Geology , Geochemistry -- South Africa -- Hotazel , Isotope geology -- South Africa -- Hotazel , Geology, Stratigraphic -- Archaean , Geology, Stratigraphic -- Proterozoic , Transvaal Supergroup (South Africa) , Great Oxidation Event
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146123 , vital:38497
- Description: Marine chemical sediments such as Banded Iron Formations deposited during the Archean-Palaeoproterozoic are studied extensively because they represent a period in the development of the Earth’s early history where the atmospheric O₂ content was below the present levels (PAL) of 21%. Prior to the Great Oxidation Event (GOE) at ca. 2.4 Ga, highly ferruginous and anoxic marine environments were dominated by extensive BIF deposition such as that of the Griqualand West Basin of the Transvaal Supergroup in South Africa. This basin is also thought to record the transition into the first rise of atmospheric O₂ in our planet, from the Koegas Subgroup to the Hotazel Formation dated at ca. 2.43 Ga (Gumsley et al., 2017). Two drill cores from the north eastern part of the Kalahari Manganese Field characterized by a well-preserved and complete intersection of the cyclic Mn-Fe Hotazel Formation were studied at a high resolution (sampled at approximately one-meter interval). Such high-resolution approach is being employed for the first time in this project, capturing in detail the three manganese rich layers intercalated with BIF and the transitions between these lithofacies. The micro-banded BIF is made up of three major phases, namely Fe-Ca-Mg carbonates (ankerite, siderite and calcite), magnetite, and silicates (chert and minor Fe-silicates); laminated transitional lutite consist of mainly hematite, chert and Mn-carbonates, whereas the manganese ore layers are made up of mostly calcic carbonates (Mn-calcite and Ca-kutnahorite) in the form of laminations and ovoids, while Mn-silicates include dominant braunite and lesser friedelite. All three lithofacies are very fine grained (sub-mm scale) and so petrographic and mineralogical observations were obtained mostly through scanning electron microscope analysis for detailed textural relationships with focus on the carbonate fraction. Bulk geochemical studies of the entire stratigraphy of the Hotazel Formation have previously provided great insights into the cyclic nature of the deposit but have not adequately considered the potential of the carbonate fraction of the rocks as a valuable proxy for understanding the chemistry of the primary depositional environment and insights into the redox processes that were at play. This is because these carbonates have always been attributed to diagenetic processes below the sediment-water interface such as microbially-mediated dissimilatory iron/manganese reduction (DIR/DMR) where the precursor/primary Fe-Mn oxyhydroxides have been reduced to result in the minerals observed today. The carbonate fraction of the BIF is made up of ankerite and siderite which co-exist in a chert matrix as anhedral to subhedral grains with no apparent replacement textures. This suggests co-precipitation of the two species which is at apparent odds with classic diagenetic models. Similarly, Mn-carbonates in the hematite lutite and manganese ore (Mn-calcite, kutnahorite, and minor rhodocrosite) co-exist in laminae and ovoids with no textures observed that would suggest an obvious sequential mode of formation during diagenesis. In this light, a carbonate-specific geochemical analysis based on the sequential Fe extraction technique of Poulton and Canfield (2005) was employed to decipher further the cyclic nature of the Hotazel Formation and its primary versus diagenetic controls. Results from the carbonate fraction analysis of the three lithofacies show a clear fractionation of iron and manganese during primary – rather than diagenetic - carbonate precipitation, suggesting a decoupling between DIR and DMR which is ultimately interpreted to have taken place in the water column. Bulk-rock concentration results for minor and trace elements such as Zr, Ti, Sc and Al have been used for the determination of either siliciclastic or volcanic detrital inputs as they are generally immobile in most natural aqueous solutions. These elements are in very low concentrations in all three lithofacies suggesting that the depositional environment had vanishingly small contributions from terrigenous or volcanic detritus. In terms of redox-sensitive transition metals, only Mo and Co appear to show an affinity for high Mn facies in the Hotazel sequence. Cobalt in particular attains a very low abundance in the Hotazel BIF layers at an average of ~ 4 ppm. This is similar to average pre-GOE BIF in South Africa and worldwide. Maxima in Co abundance are associated with transitional hematite lutite and Mn ore layers, but maxima over 100ppm are seen in within the hematite lutite and not within the Mn ore proper where maxima in Mn are recorded. This suggests a clear and direct association with the hematite fraction in the rocks, which is modally much higher in the lutites but drops substantially in the Mn layers themselves. The similarities of bulk-rock BIF and modern-day seawater REE patterns has been used as a key argument for primary controls in REE behaviour and minimal diagenetic modification. Likewise, the three lithofacies of the Hotazel Formation analysed in this study all share similar characteristics with a clear seawater signal through gentle positive slopes in the normalised abundance of LREE versus HREE. Negative Ce anomalies prevail in the entire sample set analysed, which has been interpreted before as a proxy for oxic seawater conditions. However, positive Ce anomalies that are traditionally linked to scavenging and deposition of primary tetravalent Mn oxyhydroxides (e.g., as observed in modern day ferromanganese nodules) are completely absent from the current dataset. The lack of a positive Ce anomaly in the manganese ore and peak Co association with ferric oxides and not with peak Mn, suggests that primary deposition must have occurred within an environment that was not fully oxidizing with respect to manganese. The use of stable isotopes (i.e., C and Fe) was employed to gain insights into redox processes, whether these are thought to have happened below the sediment-water interface or in contemporaneous seawater. At a small scale, all lithofacies of the Hotazel Formation record bulk-rock δ¹³C values that are low and essentially invariant about the average value of -9.5 per mil. This is independent of sharp variations in overall modal mineralogy, relative carbonate abundance and carbonate chemistry, which is clearly difficult to reconcile with in-situ diagenetic processes that predict highly variable δ¹³C signals in response to complex combinations of precursor sediment mineralogy, pore-fluid chemistry, organic carbon supply and open vs closed system diagenesis. At a stratigraphic scale, the carbonate δ¹³C (-5 to -13‰) variations between the different lithologies could instead represent temporal changes in water-column chemistry against well-developed physico-chemical gradients, depth of deposition and biological processes. The low iron isotope values recorded in the hematite lutite and manganese ore samples can be attributed to fractionation effects of initial oxidation of ferrous iron to form Fe-oxyhydroxides in the shallow parts of the basin, from an already isotopically highly depleted aqueous Fe-pool as proposed previously. The slightly higher but still negative bulk-rock δ⁵⁶Fe values of the host BIF can be attributed to water-column Fe isotopic effects at deeper levels between primary Fe oxyhydroxides and an isotopically heavier Fe(II) pool, which was subsequently preserved during diagenetic recrystallization. All above findings were combined into a conceptual model of deposition for the three different lithologies of the Hotazel Formation. The model predicts that free molecular oxygen must have been present within the shallow oceanic environment and implicates both Mn and Fe as active redox “players” compared to classic models that apply to the origin of worldwide BIF prior to the GOE. The deposition of the Hotazel strata is interpreted to have occurred through the following three stages: (1) BIF deposition occurred in a relatively deep oceanic environment above the Ongeluk lavas during marine transgression, where a redoxcline and seawater stratification separated hydrothermally sourced iron and manganese, in response to an active Mn-shuttle mechanism linked to Mn redox cycling. Abundant ferrous iron must have been oxidized by available oxygen but also by oxidised Mn species (MnOOH) and possibly even some soluble Mn(III) complexes. Through this process, Mn(III) was being effectively reduced back into solution along with cobalt(III), as Mn(II) and Co(II) respectively, thus creating maxima in their concentrations. A drawdown of Fe(OH)₃ particles was therefore the only net precipitation mechanism at this stage. Carbonate species of Fe and the abundant magnetite would possibly have formed by reaction between the ferric hydroxides and the deeper Fe(II) pool, while organic matter would also have reacted in the water-column via DIR, accounting for the low δ¹³C signature of Fe carbonate minerals. (2) Hematite lutite formation would have occurred at a relatively shallower environment during marine regression. At this stage, reductive cycling of Fe was minimal in the absence of a deeper Fe(II) reservoir reacting with the ferric primary precipitates. Therefore, DIR progressively gave way to manganese reduction and organic carbon oxidation (DMR), which reduced MnOOH to form Mn(II)-rich carbonates in the form of kutnahorite and Mn-calcite. Co-bearing Fe(OH)₃ would have precipitated and was ultimately preserved as Co-bearing hematite during diagenesis. (3) Deposition of manganese-rich sediment occurred at even shallower oceanic depths (maximum regression) where aerobic organic carbon oxidation replaced DMR, resulting in Ca-rich carbonates such as Mn-bearing calcite and Ca-kutnahorite, yet with a low carbon isotope signature recording aerobic conditions of organic carbon cycling. Mn(III) reduction at this stage was curtailed, leading to massive precipitation of MnOOH which was diagenetically transformed into braunite and friedelite. Simultaneous precipitation of Co-bearing Fe(OH)₃ would have continued but at much more subdued rates. Repeated transgressive-regressive cycles resulted in the cyclic BIF-hematite lutite- manganese ore nature of the Hotazel Formation in an oxidized oceanic environment at the onset of the Great Oxidation Event, which was nonetheless never oxic enough to drive Mn(II) oxidation fully to its tetravalent state. The mineralogy and species-specific geochemistry of the Hotazel strata, and more specifically the carbonate fraction thereof, appear to faithfully capture the chemistry of the primary depositional environment in a progressively evolving Earth System. This project opens the door for more studies focusing on better constraining primary versus diagenetic depositional 2020 Hotazel Fe and Mn deposition mechanisms of iron and manganese during the period leading up to the GOE, and possibly re-defining the significance of Fe and Mn as invaluable redox proxies in a rapidly changing planet.
- Full Text:
- Date Issued: 2020
- Authors: Mhlanga, Xolane Reginald
- Date: 2020
- Subjects: Manganese ores -- South Africa -- Hotazel , Manganese ores -- Geology , Iron ores -- South Africa -- Hotazel , Iron ores -- Geology , Geochemistry -- South Africa -- Hotazel , Isotope geology -- South Africa -- Hotazel , Geology, Stratigraphic -- Archaean , Geology, Stratigraphic -- Proterozoic , Transvaal Supergroup (South Africa) , Great Oxidation Event
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146123 , vital:38497
- Description: Marine chemical sediments such as Banded Iron Formations deposited during the Archean-Palaeoproterozoic are studied extensively because they represent a period in the development of the Earth’s early history where the atmospheric O₂ content was below the present levels (PAL) of 21%. Prior to the Great Oxidation Event (GOE) at ca. 2.4 Ga, highly ferruginous and anoxic marine environments were dominated by extensive BIF deposition such as that of the Griqualand West Basin of the Transvaal Supergroup in South Africa. This basin is also thought to record the transition into the first rise of atmospheric O₂ in our planet, from the Koegas Subgroup to the Hotazel Formation dated at ca. 2.43 Ga (Gumsley et al., 2017). Two drill cores from the north eastern part of the Kalahari Manganese Field characterized by a well-preserved and complete intersection of the cyclic Mn-Fe Hotazel Formation were studied at a high resolution (sampled at approximately one-meter interval). Such high-resolution approach is being employed for the first time in this project, capturing in detail the three manganese rich layers intercalated with BIF and the transitions between these lithofacies. The micro-banded BIF is made up of three major phases, namely Fe-Ca-Mg carbonates (ankerite, siderite and calcite), magnetite, and silicates (chert and minor Fe-silicates); laminated transitional lutite consist of mainly hematite, chert and Mn-carbonates, whereas the manganese ore layers are made up of mostly calcic carbonates (Mn-calcite and Ca-kutnahorite) in the form of laminations and ovoids, while Mn-silicates include dominant braunite and lesser friedelite. All three lithofacies are very fine grained (sub-mm scale) and so petrographic and mineralogical observations were obtained mostly through scanning electron microscope analysis for detailed textural relationships with focus on the carbonate fraction. Bulk geochemical studies of the entire stratigraphy of the Hotazel Formation have previously provided great insights into the cyclic nature of the deposit but have not adequately considered the potential of the carbonate fraction of the rocks as a valuable proxy for understanding the chemistry of the primary depositional environment and insights into the redox processes that were at play. This is because these carbonates have always been attributed to diagenetic processes below the sediment-water interface such as microbially-mediated dissimilatory iron/manganese reduction (DIR/DMR) where the precursor/primary Fe-Mn oxyhydroxides have been reduced to result in the minerals observed today. The carbonate fraction of the BIF is made up of ankerite and siderite which co-exist in a chert matrix as anhedral to subhedral grains with no apparent replacement textures. This suggests co-precipitation of the two species which is at apparent odds with classic diagenetic models. Similarly, Mn-carbonates in the hematite lutite and manganese ore (Mn-calcite, kutnahorite, and minor rhodocrosite) co-exist in laminae and ovoids with no textures observed that would suggest an obvious sequential mode of formation during diagenesis. In this light, a carbonate-specific geochemical analysis based on the sequential Fe extraction technique of Poulton and Canfield (2005) was employed to decipher further the cyclic nature of the Hotazel Formation and its primary versus diagenetic controls. Results from the carbonate fraction analysis of the three lithofacies show a clear fractionation of iron and manganese during primary – rather than diagenetic - carbonate precipitation, suggesting a decoupling between DIR and DMR which is ultimately interpreted to have taken place in the water column. Bulk-rock concentration results for minor and trace elements such as Zr, Ti, Sc and Al have been used for the determination of either siliciclastic or volcanic detrital inputs as they are generally immobile in most natural aqueous solutions. These elements are in very low concentrations in all three lithofacies suggesting that the depositional environment had vanishingly small contributions from terrigenous or volcanic detritus. In terms of redox-sensitive transition metals, only Mo and Co appear to show an affinity for high Mn facies in the Hotazel sequence. Cobalt in particular attains a very low abundance in the Hotazel BIF layers at an average of ~ 4 ppm. This is similar to average pre-GOE BIF in South Africa and worldwide. Maxima in Co abundance are associated with transitional hematite lutite and Mn ore layers, but maxima over 100ppm are seen in within the hematite lutite and not within the Mn ore proper where maxima in Mn are recorded. This suggests a clear and direct association with the hematite fraction in the rocks, which is modally much higher in the lutites but drops substantially in the Mn layers themselves. The similarities of bulk-rock BIF and modern-day seawater REE patterns has been used as a key argument for primary controls in REE behaviour and minimal diagenetic modification. Likewise, the three lithofacies of the Hotazel Formation analysed in this study all share similar characteristics with a clear seawater signal through gentle positive slopes in the normalised abundance of LREE versus HREE. Negative Ce anomalies prevail in the entire sample set analysed, which has been interpreted before as a proxy for oxic seawater conditions. However, positive Ce anomalies that are traditionally linked to scavenging and deposition of primary tetravalent Mn oxyhydroxides (e.g., as observed in modern day ferromanganese nodules) are completely absent from the current dataset. The lack of a positive Ce anomaly in the manganese ore and peak Co association with ferric oxides and not with peak Mn, suggests that primary deposition must have occurred within an environment that was not fully oxidizing with respect to manganese. The use of stable isotopes (i.e., C and Fe) was employed to gain insights into redox processes, whether these are thought to have happened below the sediment-water interface or in contemporaneous seawater. At a small scale, all lithofacies of the Hotazel Formation record bulk-rock δ¹³C values that are low and essentially invariant about the average value of -9.5 per mil. This is independent of sharp variations in overall modal mineralogy, relative carbonate abundance and carbonate chemistry, which is clearly difficult to reconcile with in-situ diagenetic processes that predict highly variable δ¹³C signals in response to complex combinations of precursor sediment mineralogy, pore-fluid chemistry, organic carbon supply and open vs closed system diagenesis. At a stratigraphic scale, the carbonate δ¹³C (-5 to -13‰) variations between the different lithologies could instead represent temporal changes in water-column chemistry against well-developed physico-chemical gradients, depth of deposition and biological processes. The low iron isotope values recorded in the hematite lutite and manganese ore samples can be attributed to fractionation effects of initial oxidation of ferrous iron to form Fe-oxyhydroxides in the shallow parts of the basin, from an already isotopically highly depleted aqueous Fe-pool as proposed previously. The slightly higher but still negative bulk-rock δ⁵⁶Fe values of the host BIF can be attributed to water-column Fe isotopic effects at deeper levels between primary Fe oxyhydroxides and an isotopically heavier Fe(II) pool, which was subsequently preserved during diagenetic recrystallization. All above findings were combined into a conceptual model of deposition for the three different lithologies of the Hotazel Formation. The model predicts that free molecular oxygen must have been present within the shallow oceanic environment and implicates both Mn and Fe as active redox “players” compared to classic models that apply to the origin of worldwide BIF prior to the GOE. The deposition of the Hotazel strata is interpreted to have occurred through the following three stages: (1) BIF deposition occurred in a relatively deep oceanic environment above the Ongeluk lavas during marine transgression, where a redoxcline and seawater stratification separated hydrothermally sourced iron and manganese, in response to an active Mn-shuttle mechanism linked to Mn redox cycling. Abundant ferrous iron must have been oxidized by available oxygen but also by oxidised Mn species (MnOOH) and possibly even some soluble Mn(III) complexes. Through this process, Mn(III) was being effectively reduced back into solution along with cobalt(III), as Mn(II) and Co(II) respectively, thus creating maxima in their concentrations. A drawdown of Fe(OH)₃ particles was therefore the only net precipitation mechanism at this stage. Carbonate species of Fe and the abundant magnetite would possibly have formed by reaction between the ferric hydroxides and the deeper Fe(II) pool, while organic matter would also have reacted in the water-column via DIR, accounting for the low δ¹³C signature of Fe carbonate minerals. (2) Hematite lutite formation would have occurred at a relatively shallower environment during marine regression. At this stage, reductive cycling of Fe was minimal in the absence of a deeper Fe(II) reservoir reacting with the ferric primary precipitates. Therefore, DIR progressively gave way to manganese reduction and organic carbon oxidation (DMR), which reduced MnOOH to form Mn(II)-rich carbonates in the form of kutnahorite and Mn-calcite. Co-bearing Fe(OH)₃ would have precipitated and was ultimately preserved as Co-bearing hematite during diagenesis. (3) Deposition of manganese-rich sediment occurred at even shallower oceanic depths (maximum regression) where aerobic organic carbon oxidation replaced DMR, resulting in Ca-rich carbonates such as Mn-bearing calcite and Ca-kutnahorite, yet with a low carbon isotope signature recording aerobic conditions of organic carbon cycling. Mn(III) reduction at this stage was curtailed, leading to massive precipitation of MnOOH which was diagenetically transformed into braunite and friedelite. Simultaneous precipitation of Co-bearing Fe(OH)₃ would have continued but at much more subdued rates. Repeated transgressive-regressive cycles resulted in the cyclic BIF-hematite lutite- manganese ore nature of the Hotazel Formation in an oxidized oceanic environment at the onset of the Great Oxidation Event, which was nonetheless never oxic enough to drive Mn(II) oxidation fully to its tetravalent state. The mineralogy and species-specific geochemistry of the Hotazel strata, and more specifically the carbonate fraction thereof, appear to faithfully capture the chemistry of the primary depositional environment in a progressively evolving Earth System. This project opens the door for more studies focusing on better constraining primary versus diagenetic depositional 2020 Hotazel Fe and Mn deposition mechanisms of iron and manganese during the period leading up to the GOE, and possibly re-defining the significance of Fe and Mn as invaluable redox proxies in a rapidly changing planet.
- Full Text:
- Date Issued: 2020
Khoekhoe lexical borrowing in Namaqualand Afrikaans
- Authors: Christie, Camilla Rose
- Date: 2020
- Subjects: Code switching (Linguistics) , Afrikaans language -- Foreign elements -- Nama , Nama language -- Foreign elements -- Afrikaans , Afrikaans language -- Phonology , Nama language -- Phonology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/168385 , vital:41576
- Description: Although several languages in the Khoekhoe branch were historically spoken alongside Afrikaans in bilingual speech communities throughout the Western and Northern Cape, the last century has seen abrupt and catastrophic language loss, resulting in a shift from a bilingual to a monolingual paradigm. However, a number of ethnobotanical surveys conducted in the Namaqualand region of the Northern Cape over the last forty years have recorded the retention of Khoekhoe-branch plant names by monolingual Afrikaans speakers. Such surveys make no attempt to source these loanwords to their Khoekhoe-branch targets, do not make use of the standardised Namibian Khoekhoe orthography, and often resort to transcribing loaned click consonants using only ‘t’. This study undertakes a sociohistorical linguistic investigation into the etymological origins and contemporary usage of these loaned plant names in order to develop a clearer understanding of language contact and lexical borrowing in the Namaqualand region. Following the lexicographical compilation of a representative corpus of loanwords, this study conducts a series of semi-structured interviews with monolingual speakers of Namaqualand Afrikaans. Qualitative sociolinguistic analysis of these interviews reveals that, although loanwords are perceived to be of Nama origin, they are semantically opaque beyond pragmatic reference. Preliminary phonological observations identify a loss of phonemic contrastivity in loaned clicks coupled with a high incidence of variability, and suggest epenthetic stop insertion and epenthetic nasalisation as two possible strategies facilitating click loan. Synthesising these ob servations, this study speculates that the use of loanwords hosting clicks may enjoy a degree of covert prestige in Namaqualand Afrikaans, which may in turn shed light on historical sociolinguistic processes of click diffusion. It recommends that urgent and immediate attention be focused on the usage, sociolinguistic status, and regional variation of Nama within the Northern Cape, and advocates strongly for cooperation and improved communication between linguists and ethnobotanists.
- Full Text:
- Date Issued: 2020
- Authors: Christie, Camilla Rose
- Date: 2020
- Subjects: Code switching (Linguistics) , Afrikaans language -- Foreign elements -- Nama , Nama language -- Foreign elements -- Afrikaans , Afrikaans language -- Phonology , Nama language -- Phonology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/168385 , vital:41576
- Description: Although several languages in the Khoekhoe branch were historically spoken alongside Afrikaans in bilingual speech communities throughout the Western and Northern Cape, the last century has seen abrupt and catastrophic language loss, resulting in a shift from a bilingual to a monolingual paradigm. However, a number of ethnobotanical surveys conducted in the Namaqualand region of the Northern Cape over the last forty years have recorded the retention of Khoekhoe-branch plant names by monolingual Afrikaans speakers. Such surveys make no attempt to source these loanwords to their Khoekhoe-branch targets, do not make use of the standardised Namibian Khoekhoe orthography, and often resort to transcribing loaned click consonants using only ‘t’. This study undertakes a sociohistorical linguistic investigation into the etymological origins and contemporary usage of these loaned plant names in order to develop a clearer understanding of language contact and lexical borrowing in the Namaqualand region. Following the lexicographical compilation of a representative corpus of loanwords, this study conducts a series of semi-structured interviews with monolingual speakers of Namaqualand Afrikaans. Qualitative sociolinguistic analysis of these interviews reveals that, although loanwords are perceived to be of Nama origin, they are semantically opaque beyond pragmatic reference. Preliminary phonological observations identify a loss of phonemic contrastivity in loaned clicks coupled with a high incidence of variability, and suggest epenthetic stop insertion and epenthetic nasalisation as two possible strategies facilitating click loan. Synthesising these ob servations, this study speculates that the use of loanwords hosting clicks may enjoy a degree of covert prestige in Namaqualand Afrikaans, which may in turn shed light on historical sociolinguistic processes of click diffusion. It recommends that urgent and immediate attention be focused on the usage, sociolinguistic status, and regional variation of Nama within the Northern Cape, and advocates strongly for cooperation and improved communication between linguists and ethnobotanists.
- Full Text:
- Date Issued: 2020
“Why me, Lord?”: some social factors associated with the receipt of a donor heart in South Africa
- Authors: Hartle, Raymond
- Date: 2020
- Subjects: Heart -- Transplantation -- Social aspects , Heart -- Transplantation -- Recipients -- Psychology , Heart -- Transplantation -- South Africa , Chronic diseases -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/146265 , vital:38510
- Description: Since the first human-to-human heart transplant in the world was performed by Prof Chris Barnard in Cape Town in 1967, heart transplantation has become the gold standard to treat people suffering from end stage heart failure. This thesis explores heart recipients’ perceptions and experiences of their chronic heart illness before and after transplantation. It examines the medical experience in terms of the clinical diagnosis, the standard of communication about the illness and the proposed treatment, and the post-transplant regime. It also reflects how recipients make sense of heart disease and learn to live with a transplanted heart. The thesis also shows the extent to which the recipients’ culture and individual identity impact such complex medical issues as end stage heart failure and transplantation. Qualitative research was undertaken in private sector heart transplant programmes in South Africa. The study is underpinned by Mishel’s (1990) uncertainty theory as well as by social constructionism.
- Full Text:
- Date Issued: 2020
- Authors: Hartle, Raymond
- Date: 2020
- Subjects: Heart -- Transplantation -- Social aspects , Heart -- Transplantation -- Recipients -- Psychology , Heart -- Transplantation -- South Africa , Chronic diseases -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/146265 , vital:38510
- Description: Since the first human-to-human heart transplant in the world was performed by Prof Chris Barnard in Cape Town in 1967, heart transplantation has become the gold standard to treat people suffering from end stage heart failure. This thesis explores heart recipients’ perceptions and experiences of their chronic heart illness before and after transplantation. It examines the medical experience in terms of the clinical diagnosis, the standard of communication about the illness and the proposed treatment, and the post-transplant regime. It also reflects how recipients make sense of heart disease and learn to live with a transplanted heart. The thesis also shows the extent to which the recipients’ culture and individual identity impact such complex medical issues as end stage heart failure and transplantation. Qualitative research was undertaken in private sector heart transplant programmes in South Africa. The study is underpinned by Mishel’s (1990) uncertainty theory as well as by social constructionism.
- Full Text:
- Date Issued: 2020
Zimbabwean women online: an investigation of how gendered identities are negotiated in Zimbabwean women’s online spaces
- Authors: Ndlovu, Nonhlanhla
- Date: 2020
- Subjects: Woman -- Zimbabwe -- Social life and customs Social media -- Social aspects -- Zimbabwe Facebook (Firm) Women -- Zimbabwe
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140452 , vital:37890
- Description: This study is concerned with the construction of Zimbabwean women’s identities in this contemporary internet age. Two Facebook groups are of particular interest here due to the vibrant conversations that take place on a daily basis, that is, Makhox Women’s League and Baking & Cooking: ZW Women’s Diaries. Conceiving these internet sites as discursive spaces, I unpack the contesting discourses and tensions in the different narratives offered by Zimbabwean women and identify and critique the competing sets of feminine subjectivities. I achieve this by drawing on poststructuralist and postcolonialist feminist theories in order to situate these groups as cultural sites that are particularly identity defining. I particularly draw on Foucauldian theories of discourse, power and the subject to conceptualise the formation of particular discursive gendered subjectivities. With an understanding that discourse is constitutive of power relations and contestations, and that discourse should be historically contextualised in order to take into account particular conditions of existence; I draw on Mamdani’s (1996) conceptualisation of how power is organised in Africa within a historical and institutional context, and identify the bifurcated nature of the postcolonial Zimbabwean state as a colonial residue as necessitating a particular kind of subjectivity. To this end, one can understand the different femininities on Makhox Women’s League and Baking & Cooking: ZW Women’s Diaries as constituted within, and complexly negotiating, a traditional/customary discourse and a rights-based modern one. This qualitative inquiry is informed by an eclectic approach that combines methods of textual analysis that complements both critical linguistics and media studies and attends to lexical structure as well as narrative and rhetorical analysis respectively. Combined with an online ethnographic approach I employ these tools to analyse these particular Facebook groups with the understanding that as women converse daily on these platforms, they ‘govern’ each other’s conduct and thought processes in interesting ways. I argue that these conversations discursively constitute the performances of different femininities on both sites that also take into account the diasporic condition of Zimbabwean women. I show how they negotiate and mediate feminine performance and in so doing propose and contest certain ‘truths’ that are frequently validated.
- Full Text:
- Date Issued: 2020
- Authors: Ndlovu, Nonhlanhla
- Date: 2020
- Subjects: Woman -- Zimbabwe -- Social life and customs Social media -- Social aspects -- Zimbabwe Facebook (Firm) Women -- Zimbabwe
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140452 , vital:37890
- Description: This study is concerned with the construction of Zimbabwean women’s identities in this contemporary internet age. Two Facebook groups are of particular interest here due to the vibrant conversations that take place on a daily basis, that is, Makhox Women’s League and Baking & Cooking: ZW Women’s Diaries. Conceiving these internet sites as discursive spaces, I unpack the contesting discourses and tensions in the different narratives offered by Zimbabwean women and identify and critique the competing sets of feminine subjectivities. I achieve this by drawing on poststructuralist and postcolonialist feminist theories in order to situate these groups as cultural sites that are particularly identity defining. I particularly draw on Foucauldian theories of discourse, power and the subject to conceptualise the formation of particular discursive gendered subjectivities. With an understanding that discourse is constitutive of power relations and contestations, and that discourse should be historically contextualised in order to take into account particular conditions of existence; I draw on Mamdani’s (1996) conceptualisation of how power is organised in Africa within a historical and institutional context, and identify the bifurcated nature of the postcolonial Zimbabwean state as a colonial residue as necessitating a particular kind of subjectivity. To this end, one can understand the different femininities on Makhox Women’s League and Baking & Cooking: ZW Women’s Diaries as constituted within, and complexly negotiating, a traditional/customary discourse and a rights-based modern one. This qualitative inquiry is informed by an eclectic approach that combines methods of textual analysis that complements both critical linguistics and media studies and attends to lexical structure as well as narrative and rhetorical analysis respectively. Combined with an online ethnographic approach I employ these tools to analyse these particular Facebook groups with the understanding that as women converse daily on these platforms, they ‘govern’ each other’s conduct and thought processes in interesting ways. I argue that these conversations discursively constitute the performances of different femininities on both sites that also take into account the diasporic condition of Zimbabwean women. I show how they negotiate and mediate feminine performance and in so doing propose and contest certain ‘truths’ that are frequently validated.
- Full Text:
- Date Issued: 2020
Understanding popular resistance to xenophobia in South Africa: ‘people think’ and the possibility of alternative politics
- Authors: Parker, Jemima
- Date: 2020
- Subjects: Xenophobia -- South Africa , Nationalism -- South Africa , Lazarus, Sylvain -- Political and social views , Political culture -- South Africa , Social change -- South Africa -- Political aspects , Discourse analysis -- South Africa -- Political aspects , South Africa -- Politics and government -- 1994- , Political science -- Philosophy , Political sociology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115006 , vital:34069
- Description: This thesis is concerned with the crisis of xenophobia in South Africa. It argues, firstly, that xenophobia itself is not primarily a reaction to poverty, inequality, or any other set of social conditions. Rather, xenophobia must be considered to be a collective political discourse which has arisen in post-apartheid South Africa from an exclusionary conception of state nationalism. Where this work may be distinguished from the majority of research on xenophobia in South Africa is in the fact that its particular focus is on instances where ‘ordinary’ South Africans have challenged and resisted xenophobic violence in their communities through collective political mobilisation. I suggest that these sites of resistance deserve careful consideration in their own right. I argue that they may demonstrate a subjective break with the oppressive politics of state nationalism through the affirmation of alternative political conceptions. Drawing on the political theory of Sylvain Lazarus, and his principal thesis that people are capable of thinking politics in ways which can subjectively think beyond the social and the extant (underscored by his political and methodological axiom, people think), this thesis argues that these sites of resistance show that people – and especially those who are considered to be marginalised from the domain of legitimate politics – can and do think politically, and it is in the thought of people that new and potentially emancipatory visions of politics may emerge.
- Full Text:
- Date Issued: 2020
- Authors: Parker, Jemima
- Date: 2020
- Subjects: Xenophobia -- South Africa , Nationalism -- South Africa , Lazarus, Sylvain -- Political and social views , Political culture -- South Africa , Social change -- South Africa -- Political aspects , Discourse analysis -- South Africa -- Political aspects , South Africa -- Politics and government -- 1994- , Political science -- Philosophy , Political sociology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115006 , vital:34069
- Description: This thesis is concerned with the crisis of xenophobia in South Africa. It argues, firstly, that xenophobia itself is not primarily a reaction to poverty, inequality, or any other set of social conditions. Rather, xenophobia must be considered to be a collective political discourse which has arisen in post-apartheid South Africa from an exclusionary conception of state nationalism. Where this work may be distinguished from the majority of research on xenophobia in South Africa is in the fact that its particular focus is on instances where ‘ordinary’ South Africans have challenged and resisted xenophobic violence in their communities through collective political mobilisation. I suggest that these sites of resistance deserve careful consideration in their own right. I argue that they may demonstrate a subjective break with the oppressive politics of state nationalism through the affirmation of alternative political conceptions. Drawing on the political theory of Sylvain Lazarus, and his principal thesis that people are capable of thinking politics in ways which can subjectively think beyond the social and the extant (underscored by his political and methodological axiom, people think), this thesis argues that these sites of resistance show that people – and especially those who are considered to be marginalised from the domain of legitimate politics – can and do think politically, and it is in the thought of people that new and potentially emancipatory visions of politics may emerge.
- Full Text:
- Date Issued: 2020
A cloud adoption framework for South African SMEs
- Authors: Mudzamba, Ronald Ratidzo
- Date: 2020
- Subjects: Cloud computing , Cloud computing -- Security measures , Small business -- Technological innovations -- South Africa -- Eastern Cape , Small business -- Information technology -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Technology-Organisation-Environment (TOE) framework , Small to Medium Enterprises (SMEs)
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/148574 , vital:38751
- Description: Small to Medium Enterprises (SMEs) have been touted as key enablers to the economic development of most countries. Despite growing evidence that most SMEs fail within their initial years, ICTs have been found to add substantial value in facilitating their success. However, in most developing countries, ICT adoption by SMEs has been plagued with a plethora of challenges ranging from poor electricity supply, high ICT costs, lack of ICT expertise to lack of government support. While this might seem problematic for SMEs, the adoption and the use of cloud services mitigates some of these challenges. The problem, however, is that a limited amount of literature has provided guidance with regard to how the cloud adoption process should be carried out by SMEs. The objective of this research, was therefore, to address this by developing a framework that can be used by SMEs to guide them through the cloud adoption process. To this end, thirteen (13) semi-structured interviews were conducted across nine (9) SMEs in the Eastern Cape. The resultant interview transcripts were analysed using an established thematic approach; the result of which allowed for the development of a rich interpretive narrative about SME cloud adoption. Combined with theory from extant literature, this culminated in the development of a framework for cloud services adoption for SMEs in the Eastern Cape.
- Full Text:
- Date Issued: 2020
- Authors: Mudzamba, Ronald Ratidzo
- Date: 2020
- Subjects: Cloud computing , Cloud computing -- Security measures , Small business -- Technological innovations -- South Africa -- Eastern Cape , Small business -- Information technology -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Technology-Organisation-Environment (TOE) framework , Small to Medium Enterprises (SMEs)
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/148574 , vital:38751
- Description: Small to Medium Enterprises (SMEs) have been touted as key enablers to the economic development of most countries. Despite growing evidence that most SMEs fail within their initial years, ICTs have been found to add substantial value in facilitating their success. However, in most developing countries, ICT adoption by SMEs has been plagued with a plethora of challenges ranging from poor electricity supply, high ICT costs, lack of ICT expertise to lack of government support. While this might seem problematic for SMEs, the adoption and the use of cloud services mitigates some of these challenges. The problem, however, is that a limited amount of literature has provided guidance with regard to how the cloud adoption process should be carried out by SMEs. The objective of this research, was therefore, to address this by developing a framework that can be used by SMEs to guide them through the cloud adoption process. To this end, thirteen (13) semi-structured interviews were conducted across nine (9) SMEs in the Eastern Cape. The resultant interview transcripts were analysed using an established thematic approach; the result of which allowed for the development of a rich interpretive narrative about SME cloud adoption. Combined with theory from extant literature, this culminated in the development of a framework for cloud services adoption for SMEs in the Eastern Cape.
- Full Text:
- Date Issued: 2020
“When the rainbow is enuf”: black postgraduate women’s experiences and perceptions of higher education and institutional culture – a case study of Rhodes University
- Authors: Gamedze, Ayanda
- Date: 2020
- Subjects: Rhodes University , College students, Black -- South Afrca , Women college students, Black -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/147215 , vital:38605
- Description: This thesis sets out to investigate the perceptions which Black postgraduate students hold of the present-day toward Historically White Universities (hereafter referred to as HWUs) in South Africa as unique sites from which to investigate institutional culture and the legacy of educational marginalisation. Black women are of particular focus because of the interlocking nature of social inequalities that uniquely influence their comparable experience in the academy. Rhodes University, a top-ranked traditional university provides the institutional site for this investigation into HWUs. This thesis seeks to further explore the suggestion that desegregation of South Africa's institutions of higher learning have meant access, but not always acceptance. The paper explores what Black women students perceive to be Rhodes University's institutional culture and its impact on their lived realities. Subsequently, these women have learned who they are, and what place they occupy in South Africa today, through navigating a space not necessarily accommodating to Blackness and difference. There exists a plethora of literature on the issues which Black women scholars systematically encounter daily in the academy, in sub-Saharan Africa and beyond. Nonetheless, there needs to be a further inquiry on the question of belonging of Black womanhood in HWU post the student-led movements of the past few years that have renewed the challenge to South Africa's colonial past, its neoliberal present, and its scourge of gender-based violence. This paper captures an ongoing conversation around the role of Black women in addressing transformation in HWU. As a Black woman in an HWU, I found myself wondering whether there are certain experiences students like me have in common – realities with nuances we call to identify with to some extent. I collected data from six Black women with whom I conducted interviews, and used it to compile this report and its analysis. I believe that the social significance of this study speaks to the importance of hearing the stories of subaltern groups that are positioned in spaces of privilege, yet continue to be defined by the disadvantage of their gender, race, and various other factors.
- Full Text:
- Date Issued: 2020
- Authors: Gamedze, Ayanda
- Date: 2020
- Subjects: Rhodes University , College students, Black -- South Afrca , Women college students, Black -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/147215 , vital:38605
- Description: This thesis sets out to investigate the perceptions which Black postgraduate students hold of the present-day toward Historically White Universities (hereafter referred to as HWUs) in South Africa as unique sites from which to investigate institutional culture and the legacy of educational marginalisation. Black women are of particular focus because of the interlocking nature of social inequalities that uniquely influence their comparable experience in the academy. Rhodes University, a top-ranked traditional university provides the institutional site for this investigation into HWUs. This thesis seeks to further explore the suggestion that desegregation of South Africa's institutions of higher learning have meant access, but not always acceptance. The paper explores what Black women students perceive to be Rhodes University's institutional culture and its impact on their lived realities. Subsequently, these women have learned who they are, and what place they occupy in South Africa today, through navigating a space not necessarily accommodating to Blackness and difference. There exists a plethora of literature on the issues which Black women scholars systematically encounter daily in the academy, in sub-Saharan Africa and beyond. Nonetheless, there needs to be a further inquiry on the question of belonging of Black womanhood in HWU post the student-led movements of the past few years that have renewed the challenge to South Africa's colonial past, its neoliberal present, and its scourge of gender-based violence. This paper captures an ongoing conversation around the role of Black women in addressing transformation in HWU. As a Black woman in an HWU, I found myself wondering whether there are certain experiences students like me have in common – realities with nuances we call to identify with to some extent. I collected data from six Black women with whom I conducted interviews, and used it to compile this report and its analysis. I believe that the social significance of this study speaks to the importance of hearing the stories of subaltern groups that are positioned in spaces of privilege, yet continue to be defined by the disadvantage of their gender, race, and various other factors.
- Full Text:
- Date Issued: 2020
Shoutfighting and other fiction
- Authors: Rasmenike, Nonqubela Evelyn
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , Xhosa fiction -- 21st century
- Language: English , Xhosa
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144500 , vital:38351
- Description: This document consists of three parts: Part A: English Half Thesis (Creative Work) ; Part B: IsiXhosa Half Thesis (Creative Work) ; Part C: Portfolio.
- Full Text:
- Date Issued: 2020
- Authors: Rasmenike, Nonqubela Evelyn
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , Xhosa fiction -- 21st century
- Language: English , Xhosa
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144500 , vital:38351
- Description: This document consists of three parts: Part A: English Half Thesis (Creative Work) ; Part B: IsiXhosa Half Thesis (Creative Work) ; Part C: Portfolio.
- Full Text:
- Date Issued: 2020
Nutrient removal and biofuel potential of MaB-floc biomass from an integrated algal pond system treating domestic sewage
- Authors: Sibelo, Linda
- Date: 2020
- Subjects: Biomass energy , Waste products as fuel , Algal biofuels , Sewage -- Purification -- Nutrient removal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144955 , vital:38395
- Description: Integrated algal pond systems (IAPS) are a passive water treatment technology derived from the Oswald designed advanced integrated wastewater pond systems (AIWPS®) and effect wastewater treatment based on biological activity of microorganisms within the system, solar energy and gravity. The technology consists of an advanced facultative pond (AFP), a series of interconnected high rate algal oxidation ponds (HRAOP) and algal settling ponds. The symbiotic relationship between microalgae and bacteria facilitated by paddlewheel mixing of HRAOP results in the formation of biomass aggregates known as MaB-flocs. MaB-floc formation enhances nutrient abstraction, gravitational sedimentation and separation from water hence forming two product streams; recyclable water and biomass, both with valorisation potential. This work aimed to determine the suitability of MaB-floc biomass generated in the HRAOP of an IAPS treating domestic sewage as feedstock for biofuel production based on the content of carbohydrate and lipid. Nutrient removal efficiency, biomass productivity and bulk lipid and carbohydrate concentration were monitored for two consecutive three-month periods in the winter and summer seasons of 2018/19. Maximum removal efficiencies of nitrogen and phosphorus were determined as 71% and 75% respectively, demonstrating the efficiency of IAPS as a wastewater treatment technology. MaB-floc biomass productivity in winter and summer was 9.4 g/m2/d and 16.5 g/m2/d respectively indicating the heavy influence of seasonal temperature, possibly day length, and solar irradiation on biomass productivity in the HRAOP. Summer productivity was lower than the maximum theoretical productivity of 25 g/m2/d possibly due to photoinhibition of photosynthesis as well as grazing pressures caused by the proliferation of rotifers mainly of the Brachionus genus. MaB-floc biomass consistently contained higher amounts of carbohydrate than lipid despite the changes in species dominance from Scenedesmus sp. and Desmodesmus sp. in winter to Pediastrum sp. in summer. Variations in MaB-floc biomass carbohydrate content were linked to changes in nitrogen concentration, mainly in the form of nitrates. Lower nitrogen concentration significantly increased the carbohydrate content of MaB-floc biomass from 17.5 ± 0.15% to 33.5 ± 0.3 % recorded in summer. In winter, biomass carbohydrate increased from 18.3 ± 1.2% to 35.8 ± 0.3%.To induce accumulation of carbohydrates through nitrogen starvation, isolated microalgal species native to the HRAOPs of the IAPS at Institute for Environmental Biotechnology Rhodes University(EBRU) were used. The outcome from the laboratory studies showed that carbon partitioning within isolated strains could be altered from carbohydrate to lipid which is more energy-rich. Hence, exploring the biodiesel production option using HRAOP MaB-floc biomass, which had a lipid content ranging between 12.1 ± 0.64 % and 13.9 ± 0.5 %, would require a preconditioning step in the form of nitrogen starvation to enhance its lipid content. Overall, the outcome of outdoor monitoring studies on biomass biochemical composition indicated that HRAOPs operating under natural environmental conditions preferentially generated a biomass rich in carbohydrate. Therefore, anaerobic digestion may be a more viable option for HRAOP MaB-floc biomass because of the high carbohydrate levels ranging between 24.9 ± 0.6 % and 25.6 ± 1.3 % of the dry MaB-floc biomass weight. Despite the low biomass C/N ratio (7.1 to 7.8), the MaB-floc biomass can be anaerobically co-digested with a higher C/N ratio (24) substrate such as in-pond digester sludge, to improve methane yields calculated to be between 0.31 m3 CH4/ kg MaB-floc biomass and 0.33 m3 CH4/ kg MaB-floc biomass. Anaerobic digestion of biomass also produces CO2 which can be recovered and added to HRAOPs to enhance MaB-floc biomass productivity while lowering greenhouse gas emissions from a wastewater treatment plant. The digestate from the anaerobic process, which is rich in nitrogen and phosphorus can be used as a biofertiliser. Thus, a potential MaB-floc biomass biorefinery consisting of biogas and bio-fertiliser pathways can be established using IAPS treating sewage as the platform technology. IAPS is a system designed to operate in a way that is passive and without substantial environmental impact but technological innovations and a reduction in the size of the system are required to make the technology more acceptable.
- Full Text:
- Date Issued: 2020
- Authors: Sibelo, Linda
- Date: 2020
- Subjects: Biomass energy , Waste products as fuel , Algal biofuels , Sewage -- Purification -- Nutrient removal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144955 , vital:38395
- Description: Integrated algal pond systems (IAPS) are a passive water treatment technology derived from the Oswald designed advanced integrated wastewater pond systems (AIWPS®) and effect wastewater treatment based on biological activity of microorganisms within the system, solar energy and gravity. The technology consists of an advanced facultative pond (AFP), a series of interconnected high rate algal oxidation ponds (HRAOP) and algal settling ponds. The symbiotic relationship between microalgae and bacteria facilitated by paddlewheel mixing of HRAOP results in the formation of biomass aggregates known as MaB-flocs. MaB-floc formation enhances nutrient abstraction, gravitational sedimentation and separation from water hence forming two product streams; recyclable water and biomass, both with valorisation potential. This work aimed to determine the suitability of MaB-floc biomass generated in the HRAOP of an IAPS treating domestic sewage as feedstock for biofuel production based on the content of carbohydrate and lipid. Nutrient removal efficiency, biomass productivity and bulk lipid and carbohydrate concentration were monitored for two consecutive three-month periods in the winter and summer seasons of 2018/19. Maximum removal efficiencies of nitrogen and phosphorus were determined as 71% and 75% respectively, demonstrating the efficiency of IAPS as a wastewater treatment technology. MaB-floc biomass productivity in winter and summer was 9.4 g/m2/d and 16.5 g/m2/d respectively indicating the heavy influence of seasonal temperature, possibly day length, and solar irradiation on biomass productivity in the HRAOP. Summer productivity was lower than the maximum theoretical productivity of 25 g/m2/d possibly due to photoinhibition of photosynthesis as well as grazing pressures caused by the proliferation of rotifers mainly of the Brachionus genus. MaB-floc biomass consistently contained higher amounts of carbohydrate than lipid despite the changes in species dominance from Scenedesmus sp. and Desmodesmus sp. in winter to Pediastrum sp. in summer. Variations in MaB-floc biomass carbohydrate content were linked to changes in nitrogen concentration, mainly in the form of nitrates. Lower nitrogen concentration significantly increased the carbohydrate content of MaB-floc biomass from 17.5 ± 0.15% to 33.5 ± 0.3 % recorded in summer. In winter, biomass carbohydrate increased from 18.3 ± 1.2% to 35.8 ± 0.3%.To induce accumulation of carbohydrates through nitrogen starvation, isolated microalgal species native to the HRAOPs of the IAPS at Institute for Environmental Biotechnology Rhodes University(EBRU) were used. The outcome from the laboratory studies showed that carbon partitioning within isolated strains could be altered from carbohydrate to lipid which is more energy-rich. Hence, exploring the biodiesel production option using HRAOP MaB-floc biomass, which had a lipid content ranging between 12.1 ± 0.64 % and 13.9 ± 0.5 %, would require a preconditioning step in the form of nitrogen starvation to enhance its lipid content. Overall, the outcome of outdoor monitoring studies on biomass biochemical composition indicated that HRAOPs operating under natural environmental conditions preferentially generated a biomass rich in carbohydrate. Therefore, anaerobic digestion may be a more viable option for HRAOP MaB-floc biomass because of the high carbohydrate levels ranging between 24.9 ± 0.6 % and 25.6 ± 1.3 % of the dry MaB-floc biomass weight. Despite the low biomass C/N ratio (7.1 to 7.8), the MaB-floc biomass can be anaerobically co-digested with a higher C/N ratio (24) substrate such as in-pond digester sludge, to improve methane yields calculated to be between 0.31 m3 CH4/ kg MaB-floc biomass and 0.33 m3 CH4/ kg MaB-floc biomass. Anaerobic digestion of biomass also produces CO2 which can be recovered and added to HRAOPs to enhance MaB-floc biomass productivity while lowering greenhouse gas emissions from a wastewater treatment plant. The digestate from the anaerobic process, which is rich in nitrogen and phosphorus can be used as a biofertiliser. Thus, a potential MaB-floc biomass biorefinery consisting of biogas and bio-fertiliser pathways can be established using IAPS treating sewage as the platform technology. IAPS is a system designed to operate in a way that is passive and without substantial environmental impact but technological innovations and a reduction in the size of the system are required to make the technology more acceptable.
- Full Text:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
The Islamic Bloc at the United Nations Human Rights Council
- Authors: Rist, Duncan Graham
- Date: 2020
- Subjects: United Nations Human Rights Council , Organisation of Islamic Cooperation , International relations , International relations -- Moral and ethical aspects , Political leadership -- Moral and ethical aspects , Power (Social sciences) -- United States , Human rights -- International cooperation , Liberalism -- International cooperation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142759 , vital:38114
- Description: Uncertainty as to the future of the liberal international order and the position of the United States within an international system in which it is not the hegemon remains a topic of debate amongst scholars of International Relations (Acharya: 2017; Duncombe and Dunne: 2018; Ikenberry: 2009, 2011, 2014; Nye: 2012 and Monteiro: 2011/2012). Fukuyama’s (1989: 4) “end of history” has not happened and a resurgence of populist leaders within established liberal democratic countries has contributed to a rapid decline of moral and ethical leadership and has further compromised the future of the liberal international order (Duncombe and Dunne, 2018: 27). As the relative power of the United States declines and the future of the liberal international order becomes increasingly uncertain, support for its future must be sought from outside the West (Duncombe and Dunne, 2018: 25 and Ikenberry: 2009). This thesis seeks to locate where potential non-Western support for the future liberal international order may be found. It does so through an analysis of how Islamic states who are part of the Organisation of Islamic Cooperation vote on the United Nations Human Rights Council (UNHRC). The OIC has a significant presence at the UNHRC and can influence the direction of the liberal international human rights regime. The evidence examined in this research project suggests that the future liberal international order and human rights regime can indeed expect some form of cooperation from the OIC. However, the OIC, and by extension Islamic states, would likely offer more support at least for human rights, if a more common understanding were to be found.
- Full Text:
- Date Issued: 2020
- Authors: Rist, Duncan Graham
- Date: 2020
- Subjects: United Nations Human Rights Council , Organisation of Islamic Cooperation , International relations , International relations -- Moral and ethical aspects , Political leadership -- Moral and ethical aspects , Power (Social sciences) -- United States , Human rights -- International cooperation , Liberalism -- International cooperation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142759 , vital:38114
- Description: Uncertainty as to the future of the liberal international order and the position of the United States within an international system in which it is not the hegemon remains a topic of debate amongst scholars of International Relations (Acharya: 2017; Duncombe and Dunne: 2018; Ikenberry: 2009, 2011, 2014; Nye: 2012 and Monteiro: 2011/2012). Fukuyama’s (1989: 4) “end of history” has not happened and a resurgence of populist leaders within established liberal democratic countries has contributed to a rapid decline of moral and ethical leadership and has further compromised the future of the liberal international order (Duncombe and Dunne, 2018: 27). As the relative power of the United States declines and the future of the liberal international order becomes increasingly uncertain, support for its future must be sought from outside the West (Duncombe and Dunne, 2018: 25 and Ikenberry: 2009). This thesis seeks to locate where potential non-Western support for the future liberal international order may be found. It does so through an analysis of how Islamic states who are part of the Organisation of Islamic Cooperation vote on the United Nations Human Rights Council (UNHRC). The OIC has a significant presence at the UNHRC and can influence the direction of the liberal international human rights regime. The evidence examined in this research project suggests that the future liberal international order and human rights regime can indeed expect some form of cooperation from the OIC. However, the OIC, and by extension Islamic states, would likely offer more support at least for human rights, if a more common understanding were to be found.
- Full Text:
- Date Issued: 2020
Development of paper-based aptasensors for detection of Plasmodium falciparum lactate dehydrogenase in malaria
- Ogunmolasuyi, Adewoyin Martin
- Authors: Ogunmolasuyi, Adewoyin Martin
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164601 , vital:41147 , doi:10.21504/10962/164601
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020
- Full Text:
- Date Issued: 2020
- Authors: Ogunmolasuyi, Adewoyin Martin
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164601 , vital:41147 , doi:10.21504/10962/164601
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020
- Full Text:
- Date Issued: 2020
The management of lions (Panthera Leo) in small, fenced wildlife reserves
- Authors: McEvoy, Orla
- Date: 2020
- Subjects: Lion -- Behavior -- South Africa , Spatial behavior in animals -- South Africa , Animal populations -- South Africa , Game reserves -- South Africa -- Management
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143471 , vital:38249
- Description: Reintroduced lion (Panthera leo) populations pose several ecological and management challenges in small (< 1,000 km2), fenced wildlife reserves. Changes in the natural socialecological conditions of reintroduced lion populations may lead to rapid population growth and a breakdown of natural predator-prey relationships. Reduced competition with other lions also likely reduces the potential for reintroduced lions to naturally form groups. My study used a combination of questionnaire surveys with tourists, existing lion demographic data from 16 wildlife reserves across South Africa and a controlled lion social experiment to address these ecological and management issues. Tourism was the primary reason for lion reintroductions. Tourists scored lions highly in terms of preference for viewing on safari, in particular, lions in larger, natural groups and adult males. Viewing lions also enhanced a tourists’ overall safari experience. The breakdown of natural social behaviour may likely therefore reduce tourist satisfaction related to lions. The number of resident prides and male coalitions in a reserve affected lion vital rates. Lion population growth rate was highest in reserves that contained a single resident pride, and the presence of unknown adult males significantly reduced cub survival and lioness birth intervals. The ratio of male cubs born also increased in reserves with a higher density of unknown adult males. Fertility control measures (deslorelin implants and unilateral hysterectomy) were effective at limiting lion population growth. Deslorelin treatment increased the age of first reproduction or the birth interval and decreased the subsequent litter size of treated lionesses to closer reflect natural vital rates in larger (> 10, 000 km2) systems. However, there was variability in infertility response between lionesses including adverse reactions in a small proportion of treated individuals. The number of resident prides and male coalitions in a reserve affected lion social behaviour. Lionesses formed larger groups in reserves with a higher density of unknown adult female neighbours, likely driven by territory defence. Lion prides with resident cubs were generally more fragmented, likely in response to reduced competition from unknown adult males. However, in areas with a high density of unknown adult female neighbours, prides with cubs formed larger groups likely in response to heightened territory defence. Therefore, with smaller foraging group sizes, predation rate was increased in reserves with reduced competition from unknown lions. My study supports a metapopulation approach for the management of lions in small, fenced reserves, and the standardisation of lion management procedures and database management. Endorsed by the Biodiversity Management Plan for lions in South Africa, this will enhance the long-term conservation potential of isolated populations.
- Full Text:
- Date Issued: 2020
- Authors: McEvoy, Orla
- Date: 2020
- Subjects: Lion -- Behavior -- South Africa , Spatial behavior in animals -- South Africa , Animal populations -- South Africa , Game reserves -- South Africa -- Management
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143471 , vital:38249
- Description: Reintroduced lion (Panthera leo) populations pose several ecological and management challenges in small (< 1,000 km2), fenced wildlife reserves. Changes in the natural socialecological conditions of reintroduced lion populations may lead to rapid population growth and a breakdown of natural predator-prey relationships. Reduced competition with other lions also likely reduces the potential for reintroduced lions to naturally form groups. My study used a combination of questionnaire surveys with tourists, existing lion demographic data from 16 wildlife reserves across South Africa and a controlled lion social experiment to address these ecological and management issues. Tourism was the primary reason for lion reintroductions. Tourists scored lions highly in terms of preference for viewing on safari, in particular, lions in larger, natural groups and adult males. Viewing lions also enhanced a tourists’ overall safari experience. The breakdown of natural social behaviour may likely therefore reduce tourist satisfaction related to lions. The number of resident prides and male coalitions in a reserve affected lion vital rates. Lion population growth rate was highest in reserves that contained a single resident pride, and the presence of unknown adult males significantly reduced cub survival and lioness birth intervals. The ratio of male cubs born also increased in reserves with a higher density of unknown adult males. Fertility control measures (deslorelin implants and unilateral hysterectomy) were effective at limiting lion population growth. Deslorelin treatment increased the age of first reproduction or the birth interval and decreased the subsequent litter size of treated lionesses to closer reflect natural vital rates in larger (> 10, 000 km2) systems. However, there was variability in infertility response between lionesses including adverse reactions in a small proportion of treated individuals. The number of resident prides and male coalitions in a reserve affected lion social behaviour. Lionesses formed larger groups in reserves with a higher density of unknown adult female neighbours, likely driven by territory defence. Lion prides with resident cubs were generally more fragmented, likely in response to reduced competition from unknown adult males. However, in areas with a high density of unknown adult female neighbours, prides with cubs formed larger groups likely in response to heightened territory defence. Therefore, with smaller foraging group sizes, predation rate was increased in reserves with reduced competition from unknown lions. My study supports a metapopulation approach for the management of lions in small, fenced reserves, and the standardisation of lion management procedures and database management. Endorsed by the Biodiversity Management Plan for lions in South Africa, this will enhance the long-term conservation potential of isolated populations.
- Full Text:
- Date Issued: 2020
An exploration of organizational expectations of different generations of employees during change
- Authors: Kawana, Susan Mulemwa
- Date: 2020
- Subjects: Organizational change -- Psychological aspects , Organizational behavior -- Namibia -- Case studies , Employees -- Psychology -- Namibia , Organizational change -- Namibia -- Case studies , Intergenerational relations -- Namibia , Namibia. Inland Revenue Directorate , Namibia. Customs and Excise
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/142398 , vital:38076
- Description: The aim of this study is to investigate the organizational expectations of different generations of employees at the Ministry of Finance’s Inland Revenue and Customs and Excise Departments of the Republic of Namibia, which are undergoing organizational change processes. The different generations that were included in this study are Baby Boomers, Generation X, and Generation Y. The study explores the different expectations that the generations have in relation to the changes, in terms of leadership style and communication preferences. This study followed a qualitative approach. Quota sampling was used to select twelve participants for the study. The case study was carried out within a postpositivism paradigm. Data was collected by administering semi-structured, face-to-face interviews. The findings of the study indicate that there are generational differences in respect of preferred leadership styles and communication methods during organizational change. Baby Boomers and Generation X preferred a relationshiporiented leadership style, while generation Y preferred a visionary leadership style. Task-oriented leadership style was not the preferred style of any generation. Rather, in the midst of change, it seems there is a preference for relational leadership across all the Generations. In respect of communication, Baby Boomers preferred face-toface methods, Generation X preferred face-to-face and e-mail methods as sources of change communication, while Generation Y preferred a combination of communication methods. In the midst of change, it seems there is a common preference for face-to-face communication across all the Generations. Furthermore, employees generally did not feel ready for the changes. In the light of these findings, recommendations were made to guide change initiatives amongst employees of various generations. The limitations of the study were its sample size and focus on the public sector. For future research, a larger sample could be selected from all regional offices. Similar research can also be done in the private sector. The findings of the study provide an understanding of the experiences and expectations of different generations of employees during organizational change, and contribute to the body of knowledge on generational differences, readiness for change and the management of different generations as different stakeholders.
- Full Text:
- Date Issued: 2020
- Authors: Kawana, Susan Mulemwa
- Date: 2020
- Subjects: Organizational change -- Psychological aspects , Organizational behavior -- Namibia -- Case studies , Employees -- Psychology -- Namibia , Organizational change -- Namibia -- Case studies , Intergenerational relations -- Namibia , Namibia. Inland Revenue Directorate , Namibia. Customs and Excise
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/142398 , vital:38076
- Description: The aim of this study is to investigate the organizational expectations of different generations of employees at the Ministry of Finance’s Inland Revenue and Customs and Excise Departments of the Republic of Namibia, which are undergoing organizational change processes. The different generations that were included in this study are Baby Boomers, Generation X, and Generation Y. The study explores the different expectations that the generations have in relation to the changes, in terms of leadership style and communication preferences. This study followed a qualitative approach. Quota sampling was used to select twelve participants for the study. The case study was carried out within a postpositivism paradigm. Data was collected by administering semi-structured, face-to-face interviews. The findings of the study indicate that there are generational differences in respect of preferred leadership styles and communication methods during organizational change. Baby Boomers and Generation X preferred a relationshiporiented leadership style, while generation Y preferred a visionary leadership style. Task-oriented leadership style was not the preferred style of any generation. Rather, in the midst of change, it seems there is a preference for relational leadership across all the Generations. In respect of communication, Baby Boomers preferred face-toface methods, Generation X preferred face-to-face and e-mail methods as sources of change communication, while Generation Y preferred a combination of communication methods. In the midst of change, it seems there is a common preference for face-to-face communication across all the Generations. Furthermore, employees generally did not feel ready for the changes. In the light of these findings, recommendations were made to guide change initiatives amongst employees of various generations. The limitations of the study were its sample size and focus on the public sector. For future research, a larger sample could be selected from all regional offices. Similar research can also be done in the private sector. The findings of the study provide an understanding of the experiences and expectations of different generations of employees during organizational change, and contribute to the body of knowledge on generational differences, readiness for change and the management of different generations as different stakeholders.
- Full Text:
- Date Issued: 2020
A study of why some physic concepts in the South African Physical Science curriculum are poorly understood in order to develop a targeted action-research intervention for Newton’s second law
- Authors: Cobbing, Kathleen Margaret
- Date: 2020
- Subjects: Physics -- Study and teaching (Secondary) -- South Africa , Physics -- Examinations, questions, etc. -- South Africa , Motion -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146903 , vital:38575
- Description: Globally, many students show a poor understanding of concepts in high school physics and lack the necessary problem-solving skills that the course demands. The application of Newton’s second law was found to be particularly problematic through document analysis of South African examination feedback reports, as well as from an analysis of the physics examinations at a pair of well-resourced South African independent schools that follow the Independent Examination Board curriculum. Through an action-research approach, a resource for use by students was designed and modified to improve students’ understanding of this concept, while modelling problemsolving methods. The resource consisted of brief revision notes, worked examples and scaffolded exercises. The design of the resource was influenced by the theory of cognitive apprenticeship, cognitive load theory and conceptual change theory. One of the aims of the resource was to encourage students to translate between the different representations of a problem situation: symbolic, abstract, model and concrete. The impact of this resource was evaluated at a pair of schools using a mixed methods approach. This incorporated pre- and post-tests for a quantitative assessment, qualitative student evaluations and the analysis of examination scripts. There was an improvement from pre- to post-test for all four iterations of the intervention and these improvements were shown to be significant. The use of the resource led to an increase in the quality and quantity of diagrams drawn by students in subsequent assessments.
- Full Text:
- Date Issued: 2020
- Authors: Cobbing, Kathleen Margaret
- Date: 2020
- Subjects: Physics -- Study and teaching (Secondary) -- South Africa , Physics -- Examinations, questions, etc. -- South Africa , Motion -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146903 , vital:38575
- Description: Globally, many students show a poor understanding of concepts in high school physics and lack the necessary problem-solving skills that the course demands. The application of Newton’s second law was found to be particularly problematic through document analysis of South African examination feedback reports, as well as from an analysis of the physics examinations at a pair of well-resourced South African independent schools that follow the Independent Examination Board curriculum. Through an action-research approach, a resource for use by students was designed and modified to improve students’ understanding of this concept, while modelling problemsolving methods. The resource consisted of brief revision notes, worked examples and scaffolded exercises. The design of the resource was influenced by the theory of cognitive apprenticeship, cognitive load theory and conceptual change theory. One of the aims of the resource was to encourage students to translate between the different representations of a problem situation: symbolic, abstract, model and concrete. The impact of this resource was evaluated at a pair of schools using a mixed methods approach. This incorporated pre- and post-tests for a quantitative assessment, qualitative student evaluations and the analysis of examination scripts. There was an improvement from pre- to post-test for all four iterations of the intervention and these improvements were shown to be significant. The use of the resource led to an increase in the quality and quantity of diagrams drawn by students in subsequent assessments.
- Full Text:
- Date Issued: 2020
Identification of SANCDB compounds against G2019S and I2020T variants of leucine-rich repeat Kinase 2 (LRRK2) for the development of drugs against Parkinson’s Disease
- Authors: Baye, Bertha Cinthia
- Date: 2020
- Subjects: Antiparkinsonian agents , Parkinson's disease -- Treatment , Protein kinases , Parkinson's disease -- Chemotherapy , Molecules -- Models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138764 , vital:37671
- Description: Parkinson’s disease is a type of movement disorder that occurs when nerve cells in the brain stop producing dopamine. It is the second neurodegenerative disease affecting 1-2% of people above the ages of 65 years old. There is a worldwide prevalence of 7 to 10 million affected people of all cultures and race. Studies have shown that mutation that causes Parkinson’s disease result in increased kinase activity. The c.6055 G > A in exon 41 is the most prevalent LRRK2 variation which causes a substitution of glycine to serine in G2019S in the highly activated loop of its MAP kinase domain. The LRRK2 G2019S variant is the most common genetic determinant of Parkinson’s disease identified to date. This work focused on building accurate 3D models of the LRRK2 kinase domain, that were used for large-scale in silico docking against South African natural compounds from the South African Natural Compounds Database (SANCDB; https://sancdb.rubi.ru.ac.za/). Molecular docking was performed to identify compounds that formed interactions with the active site of the protein and had the lowest binding energy scores. Molecular dynamics simulations showed different movements of the protein-ligand complexes and behavioural difference of the wildtype and the variants, all three structures proved to be compact. Network analysis was done to study residue interactions, contact maps, dynamic cross correlations, average BC and average L were used to study the residue interactions and general residue contribution to the functioning of the protein..
- Full Text:
- Date Issued: 2020
- Authors: Baye, Bertha Cinthia
- Date: 2020
- Subjects: Antiparkinsonian agents , Parkinson's disease -- Treatment , Protein kinases , Parkinson's disease -- Chemotherapy , Molecules -- Models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138764 , vital:37671
- Description: Parkinson’s disease is a type of movement disorder that occurs when nerve cells in the brain stop producing dopamine. It is the second neurodegenerative disease affecting 1-2% of people above the ages of 65 years old. There is a worldwide prevalence of 7 to 10 million affected people of all cultures and race. Studies have shown that mutation that causes Parkinson’s disease result in increased kinase activity. The c.6055 G > A in exon 41 is the most prevalent LRRK2 variation which causes a substitution of glycine to serine in G2019S in the highly activated loop of its MAP kinase domain. The LRRK2 G2019S variant is the most common genetic determinant of Parkinson’s disease identified to date. This work focused on building accurate 3D models of the LRRK2 kinase domain, that were used for large-scale in silico docking against South African natural compounds from the South African Natural Compounds Database (SANCDB; https://sancdb.rubi.ru.ac.za/). Molecular docking was performed to identify compounds that formed interactions with the active site of the protein and had the lowest binding energy scores. Molecular dynamics simulations showed different movements of the protein-ligand complexes and behavioural difference of the wildtype and the variants, all three structures proved to be compact. Network analysis was done to study residue interactions, contact maps, dynamic cross correlations, average BC and average L were used to study the residue interactions and general residue contribution to the functioning of the protein..
- Full Text:
- Date Issued: 2020