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
Design, formulation and evalauation of liposomes co-loaded with human serum Albumin and Rifampicin
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Serum albumin , Rifampin , Mycobacterium tuberculosis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161780 , vital:40670
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interestingbenefits such as low immunogenicity, antioxidant properties and improving cellular uptake ofdrugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA)seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates.Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Serum albumin , Rifampin , Mycobacterium tuberculosis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161780 , vital:40670
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interestingbenefits such as low immunogenicity, antioxidant properties and improving cellular uptake ofdrugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA)seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates.Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
Design, formulation and evaluation of liposomes co-loaded with human serum albumin and rifampicin
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Rifampin , Antitubercular agents , Serum albumin , Albumins , Tuberculosis -- Treatment
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163179 , vital:41016
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interesting benefits such as low immunogenicity, antioxidant properties and improving cellular uptake of drugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA) seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates. Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. iv The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Rifampin , Antitubercular agents , Serum albumin , Albumins , Tuberculosis -- Treatment
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163179 , vital:41016
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interesting benefits such as low immunogenicity, antioxidant properties and improving cellular uptake of drugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA) seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates. Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. iv The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
Determination of nonlinear optical properties of phthalocyanine regioisomers using computational models
- Date: 2020
- Subjects: Electrochemistry , Phthalocyanines , Nanoparticles , Nonlinear optics , Nonlinear optical spectroscopy , Refraction
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/166197 , vital:41337
- Description: This work investigates the effects of the nonlinear optical properties of four different constitutional isomers (C4h, C2v, Cs, and D2h) of a series of tetrasubstituted phthalocyanines (free-base 3-4-tert-butylphenoxyether phthalocyanines, free-base 4-4-tertbutylphenoxyether phthalocyanines, SnCl2 tetra substituted 3-4-tert-butylphenoxyether phthalocyanine, and SnCl2 tetra substituted 4-4-tert-butylphenoxyether phthalocyanine). The properties investigated were the real and imaginary components of the 3rd order hyperpolarizability, as well as the excited state absorption and refraction cross sections. The investigations were performed with a z-scan over a range of laser beam intensities. This work determined the imaginary component of the 3rd order hyperpolarizability for the free-base and SnCl2 3-4-tert-butylphenoxyether phthalocyanines and 4-4-tert-butylphenoxyether phthalocyanines to be highly dependent on the excited state cross sections. The refraction caused due to the real component of the 3rd order hyperpolarizability of the phthalocyanines was also investigated, however, the values found were strongly dependent on the laser beam intensity and the cause of this was investigated. A Five-level model was developed and run on GPGPU computing devices in order to isolate the absorption and refractive cross sections. Theeffects of the regio substitution on the excited state cross sections were also investigated, and the 1st singlet excited state and 1st triplet state absorption cross sections were calculated for all constitutional isomers. It was found that the symmetry of the constitutional isomers have a disproportionately large effect on the excited state absorption when compared to the ground state absorption. The nonlinear refractive properties of all constitutional isomers were also investigated, and the values of the parametric susceptibility are reported herein. The nonlinear refraction was found to have less effect than was seen in the nonlinear absorption. The 1st singlet excited state and 1st triplet state refractive cross sections of all constitutional isomer was determined. The results indicated that if more than one excited state was present and contributing to the nonlinear refraction, then more data than was collected here would be required. However, the 1st singlet excited state cross section were successfully determined for the free-base constitutional isomers. This work concluded that the region substitution affected the excited states more than the ground state.
- Full Text:
- Date Issued: 2020
- Date: 2020
- Subjects: Electrochemistry , Phthalocyanines , Nanoparticles , Nonlinear optics , Nonlinear optical spectroscopy , Refraction
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/166197 , vital:41337
- Description: This work investigates the effects of the nonlinear optical properties of four different constitutional isomers (C4h, C2v, Cs, and D2h) of a series of tetrasubstituted phthalocyanines (free-base 3-4-tert-butylphenoxyether phthalocyanines, free-base 4-4-tertbutylphenoxyether phthalocyanines, SnCl2 tetra substituted 3-4-tert-butylphenoxyether phthalocyanine, and SnCl2 tetra substituted 4-4-tert-butylphenoxyether phthalocyanine). The properties investigated were the real and imaginary components of the 3rd order hyperpolarizability, as well as the excited state absorption and refraction cross sections. The investigations were performed with a z-scan over a range of laser beam intensities. This work determined the imaginary component of the 3rd order hyperpolarizability for the free-base and SnCl2 3-4-tert-butylphenoxyether phthalocyanines and 4-4-tert-butylphenoxyether phthalocyanines to be highly dependent on the excited state cross sections. The refraction caused due to the real component of the 3rd order hyperpolarizability of the phthalocyanines was also investigated, however, the values found were strongly dependent on the laser beam intensity and the cause of this was investigated. A Five-level model was developed and run on GPGPU computing devices in order to isolate the absorption and refractive cross sections. Theeffects of the regio substitution on the excited state cross sections were also investigated, and the 1st singlet excited state and 1st triplet state absorption cross sections were calculated for all constitutional isomers. It was found that the symmetry of the constitutional isomers have a disproportionately large effect on the excited state absorption when compared to the ground state absorption. The nonlinear refractive properties of all constitutional isomers were also investigated, and the values of the parametric susceptibility are reported herein. The nonlinear refraction was found to have less effect than was seen in the nonlinear absorption. The 1st singlet excited state and 1st triplet state refractive cross sections of all constitutional isomer was determined. The results indicated that if more than one excited state was present and contributing to the nonlinear refraction, then more data than was collected here would be required. However, the 1st singlet excited state cross section were successfully determined for the free-base constitutional isomers. This work concluded that the region substitution affected the excited states more than the ground state.
- Full Text:
- Date Issued: 2020
Developing an organisational culture in support of organisational capacity for change: the case of a South African bank
- Authors: Dhoba, Howard
- Date: 2020
- Subjects: Corporate culture , Bank management , Organizational change
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/141247 , vital:37956
- Description: Business organisations are increasingly being exposed to challenging environmental pressures. It has been widely acknowledged and observed that an organisation that crafts an effective organisational culture should be well positioned to react to these threatening changes, and to proactively seize opportunities to adapt and learn. This research study seeks to investigate how an organisational culture that supports organisational capacity for change can be developed. It analyses what a banking organisation’s espoused culture is made up of and how it was formulated. A thematic analysis of how the bank’s aspirational and innovative culture contributes to the organisation’s capacity for change is also presented. Organisational management should take a leading role in developing the values and practices that foster participation, which are then imparted to the entire organisation. The research study thus only focused on analysing the development of organisational culture from the management perspective. An interpretivist research approach was adopted, with a case study design as the research method. Data was gathered through conducting personal interviews with twelve managers from a Retail and Business Banking cluster of one of the big South African banks. Numerous interventions were employed in the organisation to develop espoused values, aspirational culture and to encourage all employees to champion innovations and constantly search for better ways to offer delighting value propositions to clients. The research findings can assist managers and organisational leaders in building their organisational capacity for change through developing an effective organisational culture that supports change initiatives. Since the research study only focused on analysing the development of organisational culture from the perspective of management, further research studies may involve employees as well, due to the fact that everyone is expected to take an active role for an organisation to display the overall capability to effectively respond to a progressively volatile environment. The research was able to reveal how key initiatives that are designed from theoretical constructs can be used to deliver on an innovative organisational culture that contributes to organisational capability for change.
- Full Text:
- Date Issued: 2020
- Authors: Dhoba, Howard
- Date: 2020
- Subjects: Corporate culture , Bank management , Organizational change
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/141247 , vital:37956
- Description: Business organisations are increasingly being exposed to challenging environmental pressures. It has been widely acknowledged and observed that an organisation that crafts an effective organisational culture should be well positioned to react to these threatening changes, and to proactively seize opportunities to adapt and learn. This research study seeks to investigate how an organisational culture that supports organisational capacity for change can be developed. It analyses what a banking organisation’s espoused culture is made up of and how it was formulated. A thematic analysis of how the bank’s aspirational and innovative culture contributes to the organisation’s capacity for change is also presented. Organisational management should take a leading role in developing the values and practices that foster participation, which are then imparted to the entire organisation. The research study thus only focused on analysing the development of organisational culture from the management perspective. An interpretivist research approach was adopted, with a case study design as the research method. Data was gathered through conducting personal interviews with twelve managers from a Retail and Business Banking cluster of one of the big South African banks. Numerous interventions were employed in the organisation to develop espoused values, aspirational culture and to encourage all employees to champion innovations and constantly search for better ways to offer delighting value propositions to clients. The research findings can assist managers and organisational leaders in building their organisational capacity for change through developing an effective organisational culture that supports change initiatives. Since the research study only focused on analysing the development of organisational culture from the perspective of management, further research studies may involve employees as well, due to the fact that everyone is expected to take an active role for an organisation to display the overall capability to effectively respond to a progressively volatile environment. The research was able to reveal how key initiatives that are designed from theoretical constructs can be used to deliver on an innovative organisational culture that contributes to organisational capability for change.
- Full Text:
- Date Issued: 2020
Developing macroinvertebrate trait- and taxonomically-based approaches for biomonitoring wadeable riverine systems in the Niger delta, Nigeria
- Authors: Edegbene, Ovie Augustine
- Date: 2020
- Subjects: Water – Pollution -- Nigeria -- Niger River Delta , Stream health -- Nigeria -- Niger River Delta , Water -- Pollution -- Measurement , Environmental monitoring -- Nigeria -- Niger River Delta , Water quality -- Nigeria -- Niger River Delta , Water quality biological assessment -- Nigeria -- Niger River Delta , Aquatic invertebrates -- Nigeria -- Niger River Delta , Stream restoration -- Nigeria -- Niger River Delta , Urban agriculture -- Nigeria -- Niger River Delta , Stream ecology -- Nigeria -- Niger River Delta
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140660 , vital:37907
- Description: Riverine systems are increasingly subjected to pollution due to rapid urbanisation, industrialisation, and agricultural activities. Increasing pollution in freshwater systems impairs water quality, causes biodiversity loss and impairs aquatic ecosystem functionality and supply of ecosystem services. Rivers in the Niger Delta region of Nigeria are particularly vulnerable to urban pollution and agricultural activities as natural forests are increasingly replaced by urbanisation and agriculture. The differential effects of these pressures on the ecological processes of these river systems are poorly explored, as is the development of appropriate biomonitoring tools for routine monitoring of river health. In this study, a physico-chemically-based approach and macroinvertebrate trait- and taxonomic- approaches were developed to better understand the effects of multiple pressures on riverine systems, while developing multimetric indices to enable sustainable management of rivers within the region. Sixty-six stations in 20 river systems within the Edo and Delta States of the Niger Delta ecoregion were monitored seasonally for a period of five (2008–2012) years. The physico-chemically based approach makes apparent the extent of degradation of rivers and streams in the Niger Delta. For each dominant land use type, river stations were classified into least impacted stations (LIS), moderately impacted stations (MIS) or heavily impacted stations (HIS). Of 11 stations within urban catchments, only two were considered least impacted, suggesting that urgent measures are necessary to revise the current trajectories of urban rivers within the region. Most of the stations designated as MIS and HIS in the urban and urban-agriculture catchments were found to be significantly correlated with increased nutrients, EC and BOD5. Characteristics of most of the MIS and HIS within rivers in urban catchments evidenced the so-called urban stream syndrome, a state of persistent degradation of urban streams. The results of the traits and ecological preferences approach showed traits sensitive to urban and urban-agriculture pollution. Traits and ecological preferences that were associated with the LIS include the possession of hardshell, moderate and high sensitivities to oxygen depletion, very large body sized individuals (>20-40mm), swimmers, flattened body shape, a preference for temporary attachment, crawling, respiration with aerial/vegetation, possession of breathing tubes, possession of strap or other apparatus for respiration, streamlined body, and a high sensitivity to oxygen depletion. Permanent attachment as an ecological preference associated with LIS was also positively correlated with increasing dissolved oxygen (DO) and was deemed a pollution sensitive ecological preference. The possession of very small body size (<5mm), associated with HIS, was deemed a pollution-tolerant trait and was negatively correlated with DO, confirming the deteriorating state of the urban and urban-agricultural rivers. The impact of urban-forestry pollution on the distribution pattern of macroinvertebrate traits and ecological preferences was also explored in the selected rivers. Traits and ecological preferences such as possession of hard-shell, large body size, and grazing as a feeding preference which were significantly positively associated with the LIS, were also either significantly positively correlated with DO, or significantly negatively correlated with increasing any two of flow velocity, water temperature, BOD5 and nutrient. These traits and ecological preferences were deemed sensitive in forested rivers receiving urban pollution. Further, burrowing, the pupa aquatic stage, and predation which were significantly positively associated with HIS on the RLQ ordination, were also significantly negatively associated with DO. These traits were deemed tolerant of forested systems receiving urban pollution. Multimetric indices (MMI) were developed, validated and applied for urban, urban-agriculture and urban-forested (MMI-urban, MMI-urban-agric and urban-forest) areas. Of the 26 metrics that satisfactorily discriminated between the LIS, the MIS, and the HIS for MMI-urban, only five metric were retained for integration into MMI-urban, they are log VeL, Hemiptera abundance, % Coleoptera + Hemiptera, % Chironomidae + Oligochaeta and Evenness index. Further, of the 18 metrics that satisfactorily discriminated between the LIS, the MIS, and the HIS for MMI-urban-agric, only 12 metrics were retained and nine proved to be redundant. The nine metrics represent different measures; two of them were retained in addition to Chironomidae/Diptera abundance, % Odonata and Oligochaeta richness. The two metrics selected in addition to the hironomidae/Diptera abundance, % Odonata and Oligochaeta richness were the Margalef index and the logarithm of relative abundance of sprawler. For the MMI-urban-forest, 14 metrics satisfactorily discriminated between the LIS, the MIS, and the HIS, and 12 metrics were retained and 11 proved to be redundant. The non-redundant metric was Trichoptera abundance. Three metrics were further selected in addition to the Trichoptera abundance which include % Chironomidae + Oligochaeta, Coleoptera + Hemiptera richness and Shannon diversity. The MMI-urban and MMI-urban-agric indices performed better for LIS designated stations compared to the MIS and HIS deignated stations. The developed indices proved effective as biomonitoring tools for assessing the ecological health of rivers in the urban and urban-agriculture catchments within the Niger Delta. Overall, the results of the macroinvertebrate traits and ecological preferences, and taxonomic approaches showed the strength in the complementarity of both approaches in developing biomonitoring tools for assessing levels of deterioration in riverine systems. The study contributes significantly to understanding the ecology of riverine systems in the Niger Delta, particularly those subject to urban stresses, agricultural activities and urban pollution in forested systems, and thus makes an important contribution to the science and practice of biomonitoring in Nigeria where such studies are sparse.
- Full Text:
- Date Issued: 2020
- Authors: Edegbene, Ovie Augustine
- Date: 2020
- Subjects: Water – Pollution -- Nigeria -- Niger River Delta , Stream health -- Nigeria -- Niger River Delta , Water -- Pollution -- Measurement , Environmental monitoring -- Nigeria -- Niger River Delta , Water quality -- Nigeria -- Niger River Delta , Water quality biological assessment -- Nigeria -- Niger River Delta , Aquatic invertebrates -- Nigeria -- Niger River Delta , Stream restoration -- Nigeria -- Niger River Delta , Urban agriculture -- Nigeria -- Niger River Delta , Stream ecology -- Nigeria -- Niger River Delta
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140660 , vital:37907
- Description: Riverine systems are increasingly subjected to pollution due to rapid urbanisation, industrialisation, and agricultural activities. Increasing pollution in freshwater systems impairs water quality, causes biodiversity loss and impairs aquatic ecosystem functionality and supply of ecosystem services. Rivers in the Niger Delta region of Nigeria are particularly vulnerable to urban pollution and agricultural activities as natural forests are increasingly replaced by urbanisation and agriculture. The differential effects of these pressures on the ecological processes of these river systems are poorly explored, as is the development of appropriate biomonitoring tools for routine monitoring of river health. In this study, a physico-chemically-based approach and macroinvertebrate trait- and taxonomic- approaches were developed to better understand the effects of multiple pressures on riverine systems, while developing multimetric indices to enable sustainable management of rivers within the region. Sixty-six stations in 20 river systems within the Edo and Delta States of the Niger Delta ecoregion were monitored seasonally for a period of five (2008–2012) years. The physico-chemically based approach makes apparent the extent of degradation of rivers and streams in the Niger Delta. For each dominant land use type, river stations were classified into least impacted stations (LIS), moderately impacted stations (MIS) or heavily impacted stations (HIS). Of 11 stations within urban catchments, only two were considered least impacted, suggesting that urgent measures are necessary to revise the current trajectories of urban rivers within the region. Most of the stations designated as MIS and HIS in the urban and urban-agriculture catchments were found to be significantly correlated with increased nutrients, EC and BOD5. Characteristics of most of the MIS and HIS within rivers in urban catchments evidenced the so-called urban stream syndrome, a state of persistent degradation of urban streams. The results of the traits and ecological preferences approach showed traits sensitive to urban and urban-agriculture pollution. Traits and ecological preferences that were associated with the LIS include the possession of hardshell, moderate and high sensitivities to oxygen depletion, very large body sized individuals (>20-40mm), swimmers, flattened body shape, a preference for temporary attachment, crawling, respiration with aerial/vegetation, possession of breathing tubes, possession of strap or other apparatus for respiration, streamlined body, and a high sensitivity to oxygen depletion. Permanent attachment as an ecological preference associated with LIS was also positively correlated with increasing dissolved oxygen (DO) and was deemed a pollution sensitive ecological preference. The possession of very small body size (<5mm), associated with HIS, was deemed a pollution-tolerant trait and was negatively correlated with DO, confirming the deteriorating state of the urban and urban-agricultural rivers. The impact of urban-forestry pollution on the distribution pattern of macroinvertebrate traits and ecological preferences was also explored in the selected rivers. Traits and ecological preferences such as possession of hard-shell, large body size, and grazing as a feeding preference which were significantly positively associated with the LIS, were also either significantly positively correlated with DO, or significantly negatively correlated with increasing any two of flow velocity, water temperature, BOD5 and nutrient. These traits and ecological preferences were deemed sensitive in forested rivers receiving urban pollution. Further, burrowing, the pupa aquatic stage, and predation which were significantly positively associated with HIS on the RLQ ordination, were also significantly negatively associated with DO. These traits were deemed tolerant of forested systems receiving urban pollution. Multimetric indices (MMI) were developed, validated and applied for urban, urban-agriculture and urban-forested (MMI-urban, MMI-urban-agric and urban-forest) areas. Of the 26 metrics that satisfactorily discriminated between the LIS, the MIS, and the HIS for MMI-urban, only five metric were retained for integration into MMI-urban, they are log VeL, Hemiptera abundance, % Coleoptera + Hemiptera, % Chironomidae + Oligochaeta and Evenness index. Further, of the 18 metrics that satisfactorily discriminated between the LIS, the MIS, and the HIS for MMI-urban-agric, only 12 metrics were retained and nine proved to be redundant. The nine metrics represent different measures; two of them were retained in addition to Chironomidae/Diptera abundance, % Odonata and Oligochaeta richness. The two metrics selected in addition to the hironomidae/Diptera abundance, % Odonata and Oligochaeta richness were the Margalef index and the logarithm of relative abundance of sprawler. For the MMI-urban-forest, 14 metrics satisfactorily discriminated between the LIS, the MIS, and the HIS, and 12 metrics were retained and 11 proved to be redundant. The non-redundant metric was Trichoptera abundance. Three metrics were further selected in addition to the Trichoptera abundance which include % Chironomidae + Oligochaeta, Coleoptera + Hemiptera richness and Shannon diversity. The MMI-urban and MMI-urban-agric indices performed better for LIS designated stations compared to the MIS and HIS deignated stations. The developed indices proved effective as biomonitoring tools for assessing the ecological health of rivers in the urban and urban-agriculture catchments within the Niger Delta. Overall, the results of the macroinvertebrate traits and ecological preferences, and taxonomic approaches showed the strength in the complementarity of both approaches in developing biomonitoring tools for assessing levels of deterioration in riverine systems. The study contributes significantly to understanding the ecology of riverine systems in the Niger Delta, particularly those subject to urban stresses, agricultural activities and urban pollution in forested systems, and thus makes an important contribution to the science and practice of biomonitoring in Nigeria where such studies are sparse.
- Full Text:
- Date Issued: 2020
Development of graphene materials and phthalocyanines for application in dye-sensitized solar cells
- Authors: Chindeka, Francis
- Date: 2020
- Subjects: Dye-sensitized solar cells , Graphene , Phthalocyanines , Molecular orbitals , Impedance spectroscopy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166092 , vital:41328
- Description: Two sets of dye-sensitized solar cells (DSSCs) were fabricated. In the first set, dye-sensitized solar cells (DSSC) were fabricated by incorporating graphene materials as catalysts at the counter electrode. Platinum was also used as a catalyst for comparative purposes. Different phthalocyanines: hydroxyl indium tetracarboxyphenoxy phthalocyanine (1), chloro indium octacarboxy phthalocyanine (2) and dibenzoic acid silicon phthalocyanine (3) were used as dyes. Complex 3 gave the highest power conversion efficiency (η) of 3.19% when using nitrogen doped reduced graphene oxide nanosheets (NrGONS) as a catalyst at the counter electrode, and TiO2 containing rGONS at the anode. The value obtained is close to 3.8% obtained when using Pt catalyst instead of NrGONS at the cathode, thus confirming that NrGONS is a promising candidate to replace the more expensive Pt. The study also shows that placing rGONS on both the anode and cathode improves efficiency. In the second set, DSSCs were fabricated by using 2(3,5-biscarboxyphenoxy), 9(10), 16(17), 23(24)-tri(tertbutyl) phthalocyaninato Cu (4) and Zn (5) complexes as dyes on the ITO-TiO2 photoanodes containing reduced graphene oxide nanosheets (rGONS) or nitrogen-doped rGONS (NrGONS). The evaluation of the assembled DSSCs revealed that using ITO-TiO2-NrGONS-CuPc (4) photoanode had the highest fill factor (FF) and power conversion efficiency (ɳ) of 69 % and 4.36 % respectively. These results show that the asymmetrical phthalocyanine complexes (4) and (5) showed significant improvement on the performance of the DSSC compared to previous work on symmetrical carboxylated phthalocyanines with ɳ = 3.19%.
- Full Text:
- Date Issued: 2020
- Authors: Chindeka, Francis
- Date: 2020
- Subjects: Dye-sensitized solar cells , Graphene , Phthalocyanines , Molecular orbitals , Impedance spectroscopy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166092 , vital:41328
- Description: Two sets of dye-sensitized solar cells (DSSCs) were fabricated. In the first set, dye-sensitized solar cells (DSSC) were fabricated by incorporating graphene materials as catalysts at the counter electrode. Platinum was also used as a catalyst for comparative purposes. Different phthalocyanines: hydroxyl indium tetracarboxyphenoxy phthalocyanine (1), chloro indium octacarboxy phthalocyanine (2) and dibenzoic acid silicon phthalocyanine (3) were used as dyes. Complex 3 gave the highest power conversion efficiency (η) of 3.19% when using nitrogen doped reduced graphene oxide nanosheets (NrGONS) as a catalyst at the counter electrode, and TiO2 containing rGONS at the anode. The value obtained is close to 3.8% obtained when using Pt catalyst instead of NrGONS at the cathode, thus confirming that NrGONS is a promising candidate to replace the more expensive Pt. The study also shows that placing rGONS on both the anode and cathode improves efficiency. In the second set, DSSCs were fabricated by using 2(3,5-biscarboxyphenoxy), 9(10), 16(17), 23(24)-tri(tertbutyl) phthalocyaninato Cu (4) and Zn (5) complexes as dyes on the ITO-TiO2 photoanodes containing reduced graphene oxide nanosheets (rGONS) or nitrogen-doped rGONS (NrGONS). The evaluation of the assembled DSSCs revealed that using ITO-TiO2-NrGONS-CuPc (4) photoanode had the highest fill factor (FF) and power conversion efficiency (ɳ) of 69 % and 4.36 % respectively. These results show that the asymmetrical phthalocyanine complexes (4) and (5) showed significant improvement on the performance of the DSSC compared to previous work on symmetrical carboxylated phthalocyanines with ɳ = 3.19%.
- Full Text:
- Date Issued: 2020
Disco
- Authors: Trantraal, Nathan
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , South African poetry (English) -- 21st century , Afrikaans fiction -- 21st century , Afrikaans poetry -- 21st century
- Language: Afrikaans , English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145217 , vital:38419
- Description: Creative writing portfolio.
- Full Text:
- Date Issued: 2020
- Authors: Trantraal, Nathan
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , South African poetry (English) -- 21st century , Afrikaans fiction -- 21st century , Afrikaans poetry -- 21st century
- Language: Afrikaans , English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145217 , vital:38419
- Description: Creative writing portfolio.
- Full Text:
- Date Issued: 2020
Discursive constructions of alcohol use and pregnancy among participants in intervention aimed at reducing Foetal Alcohol Spectrum Disorders
- Authors: Msomi, Nqobile Nomonde
- Date: 2020
- Subjects: Fetal alcohol spectrum disorders -- South Africa , Pregnancy -- Psychological aspects , Reproductive rights -- South Africa , Reproductive health -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140374 , vital:37883
- Description: South Africa’s socio-cultural and political history has had significant effects on maternal and reproductive health. The hazardous alcohol use patterns in the country have affected alcohol consumption during pregnancy. Antenatal exposure to alcohol may result in Foetal Alcohol Spectrum Disorders (FASD). The levels of FASD in particular areas of the country are the highest recorded in the world. Epidemiological studies have dominated pregnancy and FASD research in South Africa; however, recently critical scholarship seeking to contextualise the issue of drinking alcohol during pregnancy is emerging. This study forms part of a developmental/formative assessment of an alcohol and pregnancy intervention. Assessment is an important part of pilot interventions, and discourse is a key area of focus due to its constitutive role for the subjectivity of human beings and legitimation of institutional practices. Using a reproductive justice perspective and a Foucauldian approach to analysis, I identified five prominent discursive constructions of alcohol use during pregnancy produced during interviews with community educators. These interviews were conducted following training workshops with the community educators. Participants constructed their living environments as ‘wholly bad’ and ‘issue-ridden’ and positioned alcohol consumption as ‘a destroyer!’, ‘king’ and a social lubricant. They interpellated the foetus, the ‘FASD child’ and pregnant women into this context. They positioned themselves as transformed subjects able to effect change. The foetus was constructed as ‘vulnerable and important’, as opposed to the ‘defiled FASD child’. Pregnant women were constructed as ‘ignorant, preoccupied and unreceptive to knowledge’. These constructions hinged on so-called ‘scientific knowledge’ of biological processes in utero, demonstrating Foucault’s conception of the power/knowledge nexus and how its dynamics transforms knowledge of human beings. Whereas this ‘knowledge’ transformed alcohol consumption and the foetus into powerful and vulnerable subjects respectively, the circulating discourses had objectivising effects on pregnant women. The discourses of responsibilisation, the personification of the foetus, ‘the problem’ category of FASD, the discourse of difference, and the discourse of alcohol consumption as an entrenched practice were circulating around pregnant women. I suggest alterations to the identified constructions using principles of community psychology, the harm reduction model, a social model of disability and the reproductive justice perspective
- Full Text:
- Date Issued: 2020
- Authors: Msomi, Nqobile Nomonde
- Date: 2020
- Subjects: Fetal alcohol spectrum disorders -- South Africa , Pregnancy -- Psychological aspects , Reproductive rights -- South Africa , Reproductive health -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140374 , vital:37883
- Description: South Africa’s socio-cultural and political history has had significant effects on maternal and reproductive health. The hazardous alcohol use patterns in the country have affected alcohol consumption during pregnancy. Antenatal exposure to alcohol may result in Foetal Alcohol Spectrum Disorders (FASD). The levels of FASD in particular areas of the country are the highest recorded in the world. Epidemiological studies have dominated pregnancy and FASD research in South Africa; however, recently critical scholarship seeking to contextualise the issue of drinking alcohol during pregnancy is emerging. This study forms part of a developmental/formative assessment of an alcohol and pregnancy intervention. Assessment is an important part of pilot interventions, and discourse is a key area of focus due to its constitutive role for the subjectivity of human beings and legitimation of institutional practices. Using a reproductive justice perspective and a Foucauldian approach to analysis, I identified five prominent discursive constructions of alcohol use during pregnancy produced during interviews with community educators. These interviews were conducted following training workshops with the community educators. Participants constructed their living environments as ‘wholly bad’ and ‘issue-ridden’ and positioned alcohol consumption as ‘a destroyer!’, ‘king’ and a social lubricant. They interpellated the foetus, the ‘FASD child’ and pregnant women into this context. They positioned themselves as transformed subjects able to effect change. The foetus was constructed as ‘vulnerable and important’, as opposed to the ‘defiled FASD child’. Pregnant women were constructed as ‘ignorant, preoccupied and unreceptive to knowledge’. These constructions hinged on so-called ‘scientific knowledge’ of biological processes in utero, demonstrating Foucault’s conception of the power/knowledge nexus and how its dynamics transforms knowledge of human beings. Whereas this ‘knowledge’ transformed alcohol consumption and the foetus into powerful and vulnerable subjects respectively, the circulating discourses had objectivising effects on pregnant women. The discourses of responsibilisation, the personification of the foetus, ‘the problem’ category of FASD, the discourse of difference, and the discourse of alcohol consumption as an entrenched practice were circulating around pregnant women. I suggest alterations to the identified constructions using principles of community psychology, the harm reduction model, a social model of disability and the reproductive justice perspective
- Full Text:
- Date Issued: 2020
Do submarine canyons influence the structure and diversity of benthic fish assemblages on the continental shelf edge?
- Nyawo, Mpilonhle Aura June-Rose
- Authors: Nyawo, Mpilonhle Aura June-Rose
- Date: 2020
- Subjects: Submarine valleys , iSimangaliso Wetland Park (South Africa) , Biotic communities -- South Africa -- iSimangaliso Wetland Park , Groundfishes -- South Africa -- iSimangaliso Wetland Park , Marine ecology -- South Africa -- iSimangaliso Wetland Park
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167264 , vital:41462
- Description: Marine ecosystems play an important role in human welfare, such as providing food security and providing social, economic and environmental benefits to an increasing human population. However, due to the deleterious impact of overfishing as well as habitat degradation, pollution and climate change, many marine ecosystems and the substantial biodiversity they support, are under increasing threats. Submarine canyon ecosystems cut into the continental margin in all our oceans and are considered regions of enhanced diversity, abundance and biomass for many marine communities, including fish. In South Africa, the tropical Delagoa Ecoregion is characterised by numerous submarine canyons that are home to coelacanths Latimeria chalumnae, and a variety of commercially important line fish species. However, there is currently a lack of information on the ecological structure and functioning of these canyons, in relation to nearby non-canyon ecosystems. The aim of this thesis was to generate knowledge on the role of submarine canyons in influencing the benthic fish assemblage structure and diversity on the continental shelf and shelf edge within the high-latitude coral reef ecosystems in the tropical Delagoa Ecoregion of South Africa. First, a systematic literature review was conducted to examine the current knowledge on the role of submarine canyons on the benthic fish assemblages occurring on continental margins, as well as outline the trends in canyon research. For the fieldwork component of this thesis, baited remote underwater stereo-video systems were utilised to gather data. The first research chapter, chapter 3, investigated the effect of ecosystem and depth on the diversity and structure of benthic fish assemblages within iSimangaliso Wetland Park in the Delagoa Ecoregion. Data were collected in 2017 from Wright Canyon (canyon ecosystem) and adjacent slope ecosystems around the canyon (non-canyon ecosystem) at depths ranging between 70–240 m. The second research chapter, chapter 4, data were collected in 2018, from 60–100 m depths in three ubmarine canyons (Wright, Diepgat,Levens) and their adjacent habitat within iSimangaliso Wetland Park to investigate the diversity patterns and community structure of benthic fish and cons ider location as a factor. The systematic review showed that canyon research is still very much in its infancy, however more papers are expected to be published in the future. There were clear location associated biases detected, with more than 90% of the canyon research being concentrated in the Mediterranean Sea, while only one study was published from South Africa. Most of the reviewed literature focused on invertebrates, with benthic fish (including cartilaginous fish) being the second most studied taxa. A wide range of methods from both fishery- dependent and fishery-independent categories were used to gather the data of benthic fish from the canyons and adjacent areas. With over 8500 submarine canyons mapped globally, the number of submarine canyon research published and the detected location bias is of great concern. More studies are needed in order to understand the role of submarine canyons on adjacent slope habitats Overall, the results from the research chapters indicated that there were higher a bundances in the canyon ecosystem compared to the non-canyon ecosystem. In contrast, evenness and beta-diversity were higher in the non-canyon ecosystem. Relief, bottom type as well as depth played a major role in explaining the observed abundance and diversity patterns. Both evenness and beta-diversity decreased with increase in depth. The canyon and non-canyon also differed in terms of habitat structure. The canyon ecosystem was characterised by patched reef and reef habitats with high relief whereas the non-canyon ecosystem was characterised by flats and habitats, especially at shallower depths. Additionally, there were clear differences in terms of the fish community structure between the canyon and the non-canyon ecosystem. The heterogeneous and complex habitats of the canyon ecosystem were typified by species such as Epinephelus poecilonotus, Polysteganus coeruleopunctatus and Chrysoblephus puniceus in comparison to the less complex habitats outside the canyons that were preferred by species such as Lagocephalus sceleratus, and Rhinobatos leucospilus. The different locations sampled demonstrated that the canyon effect was not onsistent at all locations, with varying results detected in the different sample locations. This research demonstrates that clea r differences exists between the benthic fish assemblages associated with canyon and non-canyon ecosystems and provides important information on the role of submarine canyons in the iSimangaliso Wetland Park. From this thesis, it is clear that a ‘canyon effect’ exists in the continental shelf and shelf edge. The results suggested that heterogeneity of habitats was the most important environmental factor that differed between the canyon and non-canyon ecosystems and these differences in the habitat were driving the observed patterns. This thesis has provided a reference point, with regards to investigating the role and influence of these canyons on benthic fish assemblages occurring on the continental shelf edge. The information provided by this thesis can ultimately be used in other studies investigating benthic fish assemblages in other submarine canyons within iSimangaliso Wetland Park and the rest of South Africa./
- Full Text:
- Date Issued: 2020
- Authors: Nyawo, Mpilonhle Aura June-Rose
- Date: 2020
- Subjects: Submarine valleys , iSimangaliso Wetland Park (South Africa) , Biotic communities -- South Africa -- iSimangaliso Wetland Park , Groundfishes -- South Africa -- iSimangaliso Wetland Park , Marine ecology -- South Africa -- iSimangaliso Wetland Park
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167264 , vital:41462
- Description: Marine ecosystems play an important role in human welfare, such as providing food security and providing social, economic and environmental benefits to an increasing human population. However, due to the deleterious impact of overfishing as well as habitat degradation, pollution and climate change, many marine ecosystems and the substantial biodiversity they support, are under increasing threats. Submarine canyon ecosystems cut into the continental margin in all our oceans and are considered regions of enhanced diversity, abundance and biomass for many marine communities, including fish. In South Africa, the tropical Delagoa Ecoregion is characterised by numerous submarine canyons that are home to coelacanths Latimeria chalumnae, and a variety of commercially important line fish species. However, there is currently a lack of information on the ecological structure and functioning of these canyons, in relation to nearby non-canyon ecosystems. The aim of this thesis was to generate knowledge on the role of submarine canyons in influencing the benthic fish assemblage structure and diversity on the continental shelf and shelf edge within the high-latitude coral reef ecosystems in the tropical Delagoa Ecoregion of South Africa. First, a systematic literature review was conducted to examine the current knowledge on the role of submarine canyons on the benthic fish assemblages occurring on continental margins, as well as outline the trends in canyon research. For the fieldwork component of this thesis, baited remote underwater stereo-video systems were utilised to gather data. The first research chapter, chapter 3, investigated the effect of ecosystem and depth on the diversity and structure of benthic fish assemblages within iSimangaliso Wetland Park in the Delagoa Ecoregion. Data were collected in 2017 from Wright Canyon (canyon ecosystem) and adjacent slope ecosystems around the canyon (non-canyon ecosystem) at depths ranging between 70–240 m. The second research chapter, chapter 4, data were collected in 2018, from 60–100 m depths in three ubmarine canyons (Wright, Diepgat,Levens) and their adjacent habitat within iSimangaliso Wetland Park to investigate the diversity patterns and community structure of benthic fish and cons ider location as a factor. The systematic review showed that canyon research is still very much in its infancy, however more papers are expected to be published in the future. There were clear location associated biases detected, with more than 90% of the canyon research being concentrated in the Mediterranean Sea, while only one study was published from South Africa. Most of the reviewed literature focused on invertebrates, with benthic fish (including cartilaginous fish) being the second most studied taxa. A wide range of methods from both fishery- dependent and fishery-independent categories were used to gather the data of benthic fish from the canyons and adjacent areas. With over 8500 submarine canyons mapped globally, the number of submarine canyon research published and the detected location bias is of great concern. More studies are needed in order to understand the role of submarine canyons on adjacent slope habitats Overall, the results from the research chapters indicated that there were higher a bundances in the canyon ecosystem compared to the non-canyon ecosystem. In contrast, evenness and beta-diversity were higher in the non-canyon ecosystem. Relief, bottom type as well as depth played a major role in explaining the observed abundance and diversity patterns. Both evenness and beta-diversity decreased with increase in depth. The canyon and non-canyon also differed in terms of habitat structure. The canyon ecosystem was characterised by patched reef and reef habitats with high relief whereas the non-canyon ecosystem was characterised by flats and habitats, especially at shallower depths. Additionally, there were clear differences in terms of the fish community structure between the canyon and the non-canyon ecosystem. The heterogeneous and complex habitats of the canyon ecosystem were typified by species such as Epinephelus poecilonotus, Polysteganus coeruleopunctatus and Chrysoblephus puniceus in comparison to the less complex habitats outside the canyons that were preferred by species such as Lagocephalus sceleratus, and Rhinobatos leucospilus. The different locations sampled demonstrated that the canyon effect was not onsistent at all locations, with varying results detected in the different sample locations. This research demonstrates that clea r differences exists between the benthic fish assemblages associated with canyon and non-canyon ecosystems and provides important information on the role of submarine canyons in the iSimangaliso Wetland Park. From this thesis, it is clear that a ‘canyon effect’ exists in the continental shelf and shelf edge. The results suggested that heterogeneity of habitats was the most important environmental factor that differed between the canyon and non-canyon ecosystems and these differences in the habitat were driving the observed patterns. This thesis has provided a reference point, with regards to investigating the role and influence of these canyons on benthic fish assemblages occurring on the continental shelf edge. The information provided by this thesis can ultimately be used in other studies investigating benthic fish assemblages in other submarine canyons within iSimangaliso Wetland Park and the rest of South Africa./
- Full Text:
- Date Issued: 2020
Does the construction of ‘rapeable’ bodies constitute an instance of hermeneutical injustice?
- Authors: Weiffenbach, Michaela
- Date: 2020
- Subjects: Zuma, Jacob -- Trials, litigation, etc. , Rape -- Philosophy , Women's rights -- Africa , Women, Black -- Social conditions -- Africa , Masculinity -- Africa , Men, Black -- Africa -- Psychology , Justice (Philosophy)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145708 , vital:38460
- Description: This thesis argues that within the conventional imagination of the West, identity functions in a way that particular forms of embodiment are characterised by the experience of endured sexual vulnerability, which I argue is best understood as the construction of ‘rapeable’ bodies (Cahill 2001, 120). By this, I mean that the threat of rape is contingent upon the social and political construction of one’s identity as vulnerable. In virtue of this particular way of constructing the embodiment of certain subjectivities, there is an instance of hermeneutical injustice conferred (Fricker 2007, 114). I inquire into the function and meaning of stereotypic generalisations, prejudice and rape myths embedded within the dominant framework of the West and show how language and representation constructs these identities as ‘rapeable’. Furthermore, I consider how collective hermeneutical discourses construct Blackness, specifically Black masculinities and the construction of the ‘un-rapeable’ Black femxle body. To see how these ideas are congruous the prominent example that occurred in South Africa in 2005, namely, the Jacob Zuma rape trial comes to mind. One relevant feature of the case is that it shows how identities of race are constructed in the aftermath of apartheid and points to a Western collective imagination resistant to change. In addition, it demonstrates the triad of interrelatedness holding between the self-world-other, a relationship constituted mutually by the self and the socially constructed interpretations of identity and embodiment (du Toit 2009, 58). Lastly, the construction of ‘rapeable’ bodies is an example of how discursive narratives construct particular identities as vulnerable through rendering particular embodied subjects as sexually irrelevant and hermeneutically obscured.
- Full Text:
- Date Issued: 2020
- Authors: Weiffenbach, Michaela
- Date: 2020
- Subjects: Zuma, Jacob -- Trials, litigation, etc. , Rape -- Philosophy , Women's rights -- Africa , Women, Black -- Social conditions -- Africa , Masculinity -- Africa , Men, Black -- Africa -- Psychology , Justice (Philosophy)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145708 , vital:38460
- Description: This thesis argues that within the conventional imagination of the West, identity functions in a way that particular forms of embodiment are characterised by the experience of endured sexual vulnerability, which I argue is best understood as the construction of ‘rapeable’ bodies (Cahill 2001, 120). By this, I mean that the threat of rape is contingent upon the social and political construction of one’s identity as vulnerable. In virtue of this particular way of constructing the embodiment of certain subjectivities, there is an instance of hermeneutical injustice conferred (Fricker 2007, 114). I inquire into the function and meaning of stereotypic generalisations, prejudice and rape myths embedded within the dominant framework of the West and show how language and representation constructs these identities as ‘rapeable’. Furthermore, I consider how collective hermeneutical discourses construct Blackness, specifically Black masculinities and the construction of the ‘un-rapeable’ Black femxle body. To see how these ideas are congruous the prominent example that occurred in South Africa in 2005, namely, the Jacob Zuma rape trial comes to mind. One relevant feature of the case is that it shows how identities of race are constructed in the aftermath of apartheid and points to a Western collective imagination resistant to change. In addition, it demonstrates the triad of interrelatedness holding between the self-world-other, a relationship constituted mutually by the self and the socially constructed interpretations of identity and embodiment (du Toit 2009, 58). Lastly, the construction of ‘rapeable’ bodies is an example of how discursive narratives construct particular identities as vulnerable through rendering particular embodied subjects as sexually irrelevant and hermeneutically obscured.
- Full Text:
- Date Issued: 2020
Dynamics of stimulated luminescence in natural quartz: Thermoluminescence and phototransferred thermoluminescence
- Authors: Folley, Damilola Esther
- Date: 2020
- Subjects: Thermoluminescence , Quartz
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146255 , vital:38509
- Description: Natural quartz has remained an important mineral that is of topical interest in luminescence and dosimetry-related research. We investigate the dynamics of stimulated luminescence on this material through thermoluminescence (TL) and phototransferred thermoluminescence (PTTL). Measurements were made on unannealed natural quartz as well as quartz annealed at 800 and 1000̊C. The samples were annealed for 10 minutes and for 1 hour. The material, in its un- and annealed state has its main peak between 68 and 72̊C when measured at 1Cs ̃1 after a dose of 50 Gy. A study of dosimetric features and kinetic analysis was carried out on two prominent peaks, peak I and III for all the samples. The peaks show a sublinear dose response for irradiation doses between 10 and 300 Gy. Kinetic analysis shows that peak I is a first-order peak and peak III a general-order peak. Interestingly, we observe for peak I for the sample annealed at 800̊C for 1 hour an inverse thermal quenching behaviour. We demonstrate that a peak affected with an inverse thermal quenching-like behaviour can still show effect of thermal quenching when the dose the sample is irradiated to is significantly reduced. We ascribe the apparent dependence of thermal quenching on dose to competition between radiative and non-radiative transitions at the recombination centre. Peaks I, II, and III for all the samples were reproduced under phototransfer when the peaks, initially removed by preheating to a certain temperature are exposed to 470 and 525 nm light. The infuence of duration of illumination on the PTTL intensity of these peaks corresponding to various preheating temperatures is modelled using coupled first-order dfferential equations. The model is based on systems of acceptors and donors whose number and role depends on preheating temperature
- Full Text:
- Date Issued: 2020
- Authors: Folley, Damilola Esther
- Date: 2020
- Subjects: Thermoluminescence , Quartz
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146255 , vital:38509
- Description: Natural quartz has remained an important mineral that is of topical interest in luminescence and dosimetry-related research. We investigate the dynamics of stimulated luminescence on this material through thermoluminescence (TL) and phototransferred thermoluminescence (PTTL). Measurements were made on unannealed natural quartz as well as quartz annealed at 800 and 1000̊C. The samples were annealed for 10 minutes and for 1 hour. The material, in its un- and annealed state has its main peak between 68 and 72̊C when measured at 1Cs ̃1 after a dose of 50 Gy. A study of dosimetric features and kinetic analysis was carried out on two prominent peaks, peak I and III for all the samples. The peaks show a sublinear dose response for irradiation doses between 10 and 300 Gy. Kinetic analysis shows that peak I is a first-order peak and peak III a general-order peak. Interestingly, we observe for peak I for the sample annealed at 800̊C for 1 hour an inverse thermal quenching behaviour. We demonstrate that a peak affected with an inverse thermal quenching-like behaviour can still show effect of thermal quenching when the dose the sample is irradiated to is significantly reduced. We ascribe the apparent dependence of thermal quenching on dose to competition between radiative and non-radiative transitions at the recombination centre. Peaks I, II, and III for all the samples were reproduced under phototransfer when the peaks, initially removed by preheating to a certain temperature are exposed to 470 and 525 nm light. The infuence of duration of illumination on the PTTL intensity of these peaks corresponding to various preheating temperatures is modelled using coupled first-order dfferential equations. The model is based on systems of acceptors and donors whose number and role depends on preheating temperature
- Full Text:
- Date Issued: 2020
Ecological assessment of a temperate river system using biomonitoring techniques: a case study of the Bloukrans River system, South Africa
- Authors: Magadze, Tinotenda
- Date: 2020
- Subjects: Bloukrans River , Ecological assessment (Biology) -- South Africa , Stream ecology -- South Africa , Rivers -- Environmental aspects -- South Africa , Benthic animals -- Effect of human beings on -- South Africa , Water quality biological assessment -- South Africa , Diatoms -- South Africa -- Data processing
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142933 , vital:38177
- Description: Escalating pressures from growing human populations and environmental impacts increasingly imperil freshwater ecosystems. The Bloukrans River, which drains an urbanised and agricultural catchment in the Eastern Cape province of South Africa, is no exception. Detailed knowledge of the structure and function of the aquatic ecosystems is required in order to create models and matrices that predict, guide assessment and direct intervention on ecological integrity and water quality management in these systems. The main objectives of this research were to: examine the effects of urbanization on the benthic macroinvertebrate functional feeding guild structure among different stream orders; determine if benthic diatoms can be used as effective and reliable indicators of ionic composition and conductivity in different stream order categories and finally; to evaluate the applicability of the South African Diatom Index (SADI) and other indices in the Eastern Cape region of South Africa. Field studies were carried out to explore temporal patterns in community structure (macroinvertebrates and diatoms) and ecosystem function related to land-use patterns, instream habitat availability, and water quality parameters in the Bloukrans River system across four study periods: February (summer) and July (winter) 2016 and February (summer) and May/July (winter) 2018. The study was conducted along a gradient of impacts from less impacted agricultural headwaters to highly impacted urban sites located immediately downstream of the city of Makhanda. Macroinvertebrates were separated into functional feeding groups (FFGs) (i.e. collector-gatherer, collector-filterer, scraper, shredder, and predator) which were then used to assess the effects of selected physico-chemical variables and riparian zone condition on FFG organization. Collector-gatherers were the most abundant in the Bloukrans River and represented 71.3 % of the macroinvertebrate assemblages. Stream order 1species such as Nitzschia palea, Gomphonema parvulum, Tryblionella apiculata, Diploneis vulgaris and Staurosira elliptica. Multivariate analysis (Canonical correspondence analysis (CCA)) indicated that differences in diatom community assemblages were best explained by calcium, magnesium, pH, phosphate, nitrate, dissolved oxygen, sediment nitrate, conductivity and salinity. These results indicate that diatoms can be used as bioindicators for monitoring highly impacted river systems and to also further examine pollution gradients and impacts of specific/point pollution sources. In order to further test the application of diatom indices, nine sites with contrasting water quality were sampled along the length river system in February, May and July 2018. Diatom-based indices incorporated in OMNIDIA software were applied to assess the integrity of the water quality as indicated by diatom communities. For comparative purposes, several foreign indices (e.g. the trophic diatom index (TDI), the percentage pollution-tolerant valves (%PTV), biological diatom index (BDI)) and the South African Diatom Index (SADI) were used in the study. From the results, the Percentage Pollution-Tolerant Valves (%PTV) of most urban sites in the Bloukrans River was above the 20% limit indicating the presence of organic pollutants. Although the foreign diatom indices were applicable in the study, the SADI had significant correlations with most water quality variables (p < 0.05) compared to other indices such as Watanabe Index (WAT), Biological Index of Water Quality Trophic Index (BIWQ) and Trophic Index (TI)). These results support wider use of the SADI as an indicator of water quality conditions in South African river systems. Finally, the observed variations in diatom community structure and composition as a result of changes in water quality were broadly in agreement with the results of macroinvertebrate FFG structure indicating that the two biological indicators can, and should, be used as complementary techniques in the biomonitoring of rivers and streams in South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Magadze, Tinotenda
- Date: 2020
- Subjects: Bloukrans River , Ecological assessment (Biology) -- South Africa , Stream ecology -- South Africa , Rivers -- Environmental aspects -- South Africa , Benthic animals -- Effect of human beings on -- South Africa , Water quality biological assessment -- South Africa , Diatoms -- South Africa -- Data processing
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142933 , vital:38177
- Description: Escalating pressures from growing human populations and environmental impacts increasingly imperil freshwater ecosystems. The Bloukrans River, which drains an urbanised and agricultural catchment in the Eastern Cape province of South Africa, is no exception. Detailed knowledge of the structure and function of the aquatic ecosystems is required in order to create models and matrices that predict, guide assessment and direct intervention on ecological integrity and water quality management in these systems. The main objectives of this research were to: examine the effects of urbanization on the benthic macroinvertebrate functional feeding guild structure among different stream orders; determine if benthic diatoms can be used as effective and reliable indicators of ionic composition and conductivity in different stream order categories and finally; to evaluate the applicability of the South African Diatom Index (SADI) and other indices in the Eastern Cape region of South Africa. Field studies were carried out to explore temporal patterns in community structure (macroinvertebrates and diatoms) and ecosystem function related to land-use patterns, instream habitat availability, and water quality parameters in the Bloukrans River system across four study periods: February (summer) and July (winter) 2016 and February (summer) and May/July (winter) 2018. The study was conducted along a gradient of impacts from less impacted agricultural headwaters to highly impacted urban sites located immediately downstream of the city of Makhanda. Macroinvertebrates were separated into functional feeding groups (FFGs) (i.e. collector-gatherer, collector-filterer, scraper, shredder, and predator) which were then used to assess the effects of selected physico-chemical variables and riparian zone condition on FFG organization. Collector-gatherers were the most abundant in the Bloukrans River and represented 71.3 % of the macroinvertebrate assemblages. Stream order 1species such as Nitzschia palea, Gomphonema parvulum, Tryblionella apiculata, Diploneis vulgaris and Staurosira elliptica. Multivariate analysis (Canonical correspondence analysis (CCA)) indicated that differences in diatom community assemblages were best explained by calcium, magnesium, pH, phosphate, nitrate, dissolved oxygen, sediment nitrate, conductivity and salinity. These results indicate that diatoms can be used as bioindicators for monitoring highly impacted river systems and to also further examine pollution gradients and impacts of specific/point pollution sources. In order to further test the application of diatom indices, nine sites with contrasting water quality were sampled along the length river system in February, May and July 2018. Diatom-based indices incorporated in OMNIDIA software were applied to assess the integrity of the water quality as indicated by diatom communities. For comparative purposes, several foreign indices (e.g. the trophic diatom index (TDI), the percentage pollution-tolerant valves (%PTV), biological diatom index (BDI)) and the South African Diatom Index (SADI) were used in the study. From the results, the Percentage Pollution-Tolerant Valves (%PTV) of most urban sites in the Bloukrans River was above the 20% limit indicating the presence of organic pollutants. Although the foreign diatom indices were applicable in the study, the SADI had significant correlations with most water quality variables (p < 0.05) compared to other indices such as Watanabe Index (WAT), Biological Index of Water Quality Trophic Index (BIWQ) and Trophic Index (TI)). These results support wider use of the SADI as an indicator of water quality conditions in South African river systems. Finally, the observed variations in diatom community structure and composition as a result of changes in water quality were broadly in agreement with the results of macroinvertebrate FFG structure indicating that the two biological indicators can, and should, be used as complementary techniques in the biomonitoring of rivers and streams in South Africa.
- Full Text:
- Date Issued: 2020
Ecological engineering: an assessment of the ecological impact of Reno mattress structures used in erosion control in the Keurbooms Estuary, South Africa
- Authors: De Villiers, Nina
- Date: 2020
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Keurboomstrand , Coast changes -- South Africa -- Keurboomstrand , Shore protection -- South Africa -- Keurboomstrand , Coastal engineering-- South Africa -- Keurboomstrand , Coastal zone management-- South Africa -- Keurboomstrand , Estuarine ecology-- South Africa -- Keurboomstrand , Eelgrass -- South Africa -- Keurboomstrand , Reno Mattresses
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166138 , vital:41332
- Description: Global climate changes have been associated with ocean warming and sea-level rise. Armouring of coastlines has become common practice with the increasing threat of coastal erosion. The transformation of soft sediment habitats to hard, artificial habitats because of coastline armouring can lead to changes in species diversity, composition and distribution. It is, therefore, essential to assess changes to habitats from coastal development as well as the ecological impact erosion control structures have within coastal systems. Ecological engineering attempts to combine engineering principals and ecological processes to reduce environmental impacts from coastal development and the implementation of artificial structures. Estuaries are particularly vulnerable to anthropogenic impacts through development, and are extremely important systems offering nursery and foraging grounds for many species. These systems are, however, particularly vulnerable to anthropogenic impacts from urbanisation and development. Within South Africa many estuaries are being transformed by the addition of artificial structures to combat erosion, one such structure is the Reno mattress (a flattened wire box filled with rocks). This study compared the fish diversity and abundances of existing Reno mattress structures and natural eelgrass (Zostera capensis) habitat in the Keurbooms Estuary, South Africa. Benthic invertebrates were sampled using standard core sampling and an adapted suction sampling approach within the two habitats. The non-destructive method of mini Baited Remote Underwater Video Systems (BRUVs) was used to sample fish. Seasonal benthic invertebrate and fish abundances and assemblages were assessed from winter 2018 to spring 2019 with greater abundances of both recorded in summer. Significantly greater abundances, diversity, and richness of fish were found in the Reno mattress habitat compared to Z. capensis. Invertebrate taxa displayed some overlap between habitats, however, three higher taxonomic groups were only recorded within Reno mattress habitat and one only within the eelgrass habitat. Fish assemblages differed significantly between the two established habitats. A Before-After-Control-Impact (BACI) investigation was used to assess the ecological impact of newly installed Reno mattresses in the Keurbooms Estuary. Zostera capensis extent was sampled by determining the percentage cover of 0.5 m X 0.5 m quadrats and measurements of eelgrass blades. Percentage cover and blade length decreased during the installation of Reno mattress, but then recovered shortly after completion of the installation. Abundances, richness and diversity of invertebrates and fish were found to be similar before and after the installation which suggests that the installation had no net negative impact on the site. The Reno mattresses were found to attract fauna typical of rocky shore environments as well as a few invasive alien invertebrate species. This study noted that a hybrid habitat of Reno mattress and eelgrass was created and may in fact provide the positives of both to a system. In any coastal development it will be important to balance the demands of a growing population and the protection of natural habitats. The results of this study suggest that complex artificial structures such as Reno mattresses do provide habitat for fish and invertebrates. However, the use of these structures should be in combination with natural vegetation (e.g. as a hybrid habitat) and not one that replaces intertidal and subtidal natural habitat especially eelgrass. There is limited information regarding the ecological impacts of using Reno mattresses in estuaries and this study provides new information on their ecological efficacy that should be valuable for future coastal erosion control practices.
- Full Text:
- Date Issued: 2020
- Authors: De Villiers, Nina
- Date: 2020
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Keurboomstrand , Coast changes -- South Africa -- Keurboomstrand , Shore protection -- South Africa -- Keurboomstrand , Coastal engineering-- South Africa -- Keurboomstrand , Coastal zone management-- South Africa -- Keurboomstrand , Estuarine ecology-- South Africa -- Keurboomstrand , Eelgrass -- South Africa -- Keurboomstrand , Reno Mattresses
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166138 , vital:41332
- Description: Global climate changes have been associated with ocean warming and sea-level rise. Armouring of coastlines has become common practice with the increasing threat of coastal erosion. The transformation of soft sediment habitats to hard, artificial habitats because of coastline armouring can lead to changes in species diversity, composition and distribution. It is, therefore, essential to assess changes to habitats from coastal development as well as the ecological impact erosion control structures have within coastal systems. Ecological engineering attempts to combine engineering principals and ecological processes to reduce environmental impacts from coastal development and the implementation of artificial structures. Estuaries are particularly vulnerable to anthropogenic impacts through development, and are extremely important systems offering nursery and foraging grounds for many species. These systems are, however, particularly vulnerable to anthropogenic impacts from urbanisation and development. Within South Africa many estuaries are being transformed by the addition of artificial structures to combat erosion, one such structure is the Reno mattress (a flattened wire box filled with rocks). This study compared the fish diversity and abundances of existing Reno mattress structures and natural eelgrass (Zostera capensis) habitat in the Keurbooms Estuary, South Africa. Benthic invertebrates were sampled using standard core sampling and an adapted suction sampling approach within the two habitats. The non-destructive method of mini Baited Remote Underwater Video Systems (BRUVs) was used to sample fish. Seasonal benthic invertebrate and fish abundances and assemblages were assessed from winter 2018 to spring 2019 with greater abundances of both recorded in summer. Significantly greater abundances, diversity, and richness of fish were found in the Reno mattress habitat compared to Z. capensis. Invertebrate taxa displayed some overlap between habitats, however, three higher taxonomic groups were only recorded within Reno mattress habitat and one only within the eelgrass habitat. Fish assemblages differed significantly between the two established habitats. A Before-After-Control-Impact (BACI) investigation was used to assess the ecological impact of newly installed Reno mattresses in the Keurbooms Estuary. Zostera capensis extent was sampled by determining the percentage cover of 0.5 m X 0.5 m quadrats and measurements of eelgrass blades. Percentage cover and blade length decreased during the installation of Reno mattress, but then recovered shortly after completion of the installation. Abundances, richness and diversity of invertebrates and fish were found to be similar before and after the installation which suggests that the installation had no net negative impact on the site. The Reno mattresses were found to attract fauna typical of rocky shore environments as well as a few invasive alien invertebrate species. This study noted that a hybrid habitat of Reno mattress and eelgrass was created and may in fact provide the positives of both to a system. In any coastal development it will be important to balance the demands of a growing population and the protection of natural habitats. The results of this study suggest that complex artificial structures such as Reno mattresses do provide habitat for fish and invertebrates. However, the use of these structures should be in combination with natural vegetation (e.g. as a hybrid habitat) and not one that replaces intertidal and subtidal natural habitat especially eelgrass. There is limited information regarding the ecological impacts of using Reno mattresses in estuaries and this study provides new information on their ecological efficacy that should be valuable for future coastal erosion control practices.
- Full Text:
- Date Issued: 2020
Effect of the nature of nanoparticles on the photophysicochemical properties and photodynamic antimicrobial chemotherapy of phthalocyanines
- Authors: Magadla, Aviwe
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123107 , vital:35406
- Description: In this work, the syntheses and characterisation of Zn monocaffeic acid tri–tert–butyl phthalocyanine (1), Zn monocarboxyphenoxy tri– tert–butylphenoxyl phthalocyanine (2), tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (3) and tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (5) are presented. Complexes 3 and 5 were further quartenised with 1,3- propanesultone to form corresponding complexes (4) and (6), respectively. Complexes 1 and 2 were covalently linked to amino functionalised nanoparticles (NPs). Complexes 3, 4, 5 and 6 where linked to oleic acid/oleylamine capped (OLA/OLM) silver-iron dimers (Ag-Fe3O4 OLA/OLM) and silver-iron core shell (Ag@Fe3O4 OLA/OLM) NPs via interaction between the nanoparticles and the imino group on the phthalocyanines. The phthalocyanine-NP conjugates afforded an increase in triplet quantum yields with a corresponding decrease in fluorescence quantum yield as compared to the phthalocyanine complexes alone. Complexes 3, 4 and their conjugates were then used for photodynamic antimicrobial chemotherapy on E. coli. The zwitterionic photosensitiser 4 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2020
- Authors: Magadla, Aviwe
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123107 , vital:35406
- Description: In this work, the syntheses and characterisation of Zn monocaffeic acid tri–tert–butyl phthalocyanine (1), Zn monocarboxyphenoxy tri– tert–butylphenoxyl phthalocyanine (2), tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (3) and tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (5) are presented. Complexes 3 and 5 were further quartenised with 1,3- propanesultone to form corresponding complexes (4) and (6), respectively. Complexes 1 and 2 were covalently linked to amino functionalised nanoparticles (NPs). Complexes 3, 4, 5 and 6 where linked to oleic acid/oleylamine capped (OLA/OLM) silver-iron dimers (Ag-Fe3O4 OLA/OLM) and silver-iron core shell (Ag@Fe3O4 OLA/OLM) NPs via interaction between the nanoparticles and the imino group on the phthalocyanines. The phthalocyanine-NP conjugates afforded an increase in triplet quantum yields with a corresponding decrease in fluorescence quantum yield as compared to the phthalocyanine complexes alone. Complexes 3, 4 and their conjugates were then used for photodynamic antimicrobial chemotherapy on E. coli. The zwitterionic photosensitiser 4 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2020
Effectiveness of different interventions to reduce occupational sitting among office administrators at Rhodes University
- Authors: Malesa, Thato
- Date: 2020
- Subjects: Standing position , Sedentary behavior , Work environment , Employee health promotion , Office furniture -- Design , Industrial hygiene , Employees -- Health risk assessment , Human engineering , Compliance
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166403 , vital:41360
- Description: Background: Sitting for prolonged periods is common in the working environment. Office workers are exposed to long periods of sitting time at work. Research has reported associations between prolonged sitting and negative health implications. As such studies have proposed different interventions aimed at reducing sitting times in the workplace. The aim of the current study was to evaluate the effectiveness of two different interventions, physical intervention (sit-stand worktables) and personal intervention (instruction to stretch) on compliance and reducing occupational sitting behaviour. The study also aimed to investigate the effectiveness of interventions in improving or impairing mood. Methods: The study took the form of a fieldbased study atRhodes University, Makhanda, South Africa. Fifteen full–time office workers in different divisions participated in the study. Participants were randomly allocated to either the physical or personal intervention group. In both intervention groups, partic ipants were prompted to stand for five minutes every hour during the workday to either work in a standing position or perform stretches. Over the course of the experiment, desk occupancy, sitting/standing time and mood effect were recorded in both intervention groups Both intervention groups were monitored for a period of three months (58 days). Results: The study found that the physical intervention group was an effective approach to reduce prolonged sitting in the workplace in comparison to the personal intervention group. Over the course of the experiment, there was sustain usage of interventions in both groups, however, in the physical intervention group desk usage decreased overtime. The findings of the study also show that some participants were more compliant with the study procedures than others. It was also found that mood improved upon introducing interventions in the workplace. However, with the outcomes of the results, the study acknowledges that several factors emerged which are likely to impact compliance, which future studies may investigate. Conclusion: Although sit-stand worktables are expensive, it seems like introducing them was successful in reducing sitting time and changing sitting behaviour in comparison to an intervention that instruct s individuals to stand up and stretch.
- Full Text:
- Date Issued: 2020
- Authors: Malesa, Thato
- Date: 2020
- Subjects: Standing position , Sedentary behavior , Work environment , Employee health promotion , Office furniture -- Design , Industrial hygiene , Employees -- Health risk assessment , Human engineering , Compliance
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166403 , vital:41360
- Description: Background: Sitting for prolonged periods is common in the working environment. Office workers are exposed to long periods of sitting time at work. Research has reported associations between prolonged sitting and negative health implications. As such studies have proposed different interventions aimed at reducing sitting times in the workplace. The aim of the current study was to evaluate the effectiveness of two different interventions, physical intervention (sit-stand worktables) and personal intervention (instruction to stretch) on compliance and reducing occupational sitting behaviour. The study also aimed to investigate the effectiveness of interventions in improving or impairing mood. Methods: The study took the form of a fieldbased study atRhodes University, Makhanda, South Africa. Fifteen full–time office workers in different divisions participated in the study. Participants were randomly allocated to either the physical or personal intervention group. In both intervention groups, partic ipants were prompted to stand for five minutes every hour during the workday to either work in a standing position or perform stretches. Over the course of the experiment, desk occupancy, sitting/standing time and mood effect were recorded in both intervention groups Both intervention groups were monitored for a period of three months (58 days). Results: The study found that the physical intervention group was an effective approach to reduce prolonged sitting in the workplace in comparison to the personal intervention group. Over the course of the experiment, there was sustain usage of interventions in both groups, however, in the physical intervention group desk usage decreased overtime. The findings of the study also show that some participants were more compliant with the study procedures than others. It was also found that mood improved upon introducing interventions in the workplace. However, with the outcomes of the results, the study acknowledges that several factors emerged which are likely to impact compliance, which future studies may investigate. Conclusion: Although sit-stand worktables are expensive, it seems like introducing them was successful in reducing sitting time and changing sitting behaviour in comparison to an intervention that instruct s individuals to stand up and stretch.
- Full Text:
- Date Issued: 2020
Either way you die: a collection of short stories
- Authors: Sithole, Sipho
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145081 , vital:38406
- Description: Part A: Thesis (Creative Work); Part B: Portfolio.
- Full Text:
- Date Issued: 2020
- Authors: Sithole, Sipho
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145081 , vital:38406
- Description: Part A: Thesis (Creative Work); Part B: Portfolio.
- Full Text:
- Date Issued: 2020
Enactment of hands-on practical activities through using easily accessible resources in a Grade 10 Physical Science classroom
- Authors: Ndevahoma, Martha Kashike
- Date: 2020
- Subjects: Physical science -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/110229 , vital:33251
- Description: The Namibian National Subject Policy Guide for Physical Science Grade 8-12 (MoE, 2010) indicates that science teachers should be creative and innovative in producing their own teaching and learning support materials that are linked to practice. Practical activities play a major role in the learning of science. Due to the lack of science laboratory equipment, however, minimal practical activities are done in some schools especially under-resourced disadvantaged schools. It is against this background that this case study investigated the possibilities and challenges associated with the use of easily accessible resources to carry out hands-on practical activities. Underpinned by an interpretive paradigm, this study used a mixed-method approach by generating both quantitative and qualitative data. It was carried out in the Otjozondjupa region in Namibia at Wato Secondary School (pseudonym). It was conducted with a Grade 10 Physical Science class consisting of 30 learners. To generate data, questionnaires, focus group interviews, lesson observations, stimulated recall interviews, as well as learners’ journal reflections were used. Conceptions, dispositions, interest and sense-making were used as conceptual lenses while Vygotsky’s social constructivism was the theoretical framework that informed this study. Quantitative data were analysed using the conceptual lenses and were subsequently presented in tables and graphs. That is, a deductive approach to analysis was used. On the other hand, a thematic approach was used to analyse the qualitative data. That is, qualitative data were inductively analysed to come up with sub-themes and themes. The findings from this study revealed significant shifts in learners’ conceptions, dispositions and interest towards science after the use of easily accessible resources to do hands-on practical activities. Similarly, learners’ sense-making of science concepts improved. This study thus recommends that science teachers should, where possible, make use of easily accessible resources to carry out hands-on practical activities during their science lessons. During such hands-on practicals, however, emphasis should be on the development of scientific concepts.
- Full Text:
- Date Issued: 2020
- Authors: Ndevahoma, Martha Kashike
- Date: 2020
- Subjects: Physical science -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/110229 , vital:33251
- Description: The Namibian National Subject Policy Guide for Physical Science Grade 8-12 (MoE, 2010) indicates that science teachers should be creative and innovative in producing their own teaching and learning support materials that are linked to practice. Practical activities play a major role in the learning of science. Due to the lack of science laboratory equipment, however, minimal practical activities are done in some schools especially under-resourced disadvantaged schools. It is against this background that this case study investigated the possibilities and challenges associated with the use of easily accessible resources to carry out hands-on practical activities. Underpinned by an interpretive paradigm, this study used a mixed-method approach by generating both quantitative and qualitative data. It was carried out in the Otjozondjupa region in Namibia at Wato Secondary School (pseudonym). It was conducted with a Grade 10 Physical Science class consisting of 30 learners. To generate data, questionnaires, focus group interviews, lesson observations, stimulated recall interviews, as well as learners’ journal reflections were used. Conceptions, dispositions, interest and sense-making were used as conceptual lenses while Vygotsky’s social constructivism was the theoretical framework that informed this study. Quantitative data were analysed using the conceptual lenses and were subsequently presented in tables and graphs. That is, a deductive approach to analysis was used. On the other hand, a thematic approach was used to analyse the qualitative data. That is, qualitative data were inductively analysed to come up with sub-themes and themes. The findings from this study revealed significant shifts in learners’ conceptions, dispositions and interest towards science after the use of easily accessible resources to do hands-on practical activities. Similarly, learners’ sense-making of science concepts improved. This study thus recommends that science teachers should, where possible, make use of easily accessible resources to carry out hands-on practical activities during their science lessons. During such hands-on practicals, however, emphasis should be on the development of scientific concepts.
- Full Text:
- Date Issued: 2020
Enriching my teaching around the inverse order relationship in unit fractions at the Grade 5 level through the inclusion of musical activities: an action research case study
- Authors: Lovemore, Tarryn Shirley
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa -- Case studies , Interdisciplinary approach in education -- South Africa -- Case studies , Music -- Study and teaching (Elementary) -- South Africa -- Case studies , Music -- Mathematics , Musical notation -- Study and teaching (Elementary)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142431 , vital:38079
- Description: This research study explored how the use of musical activities, specifically based on note values, might enrich my teaching around the inverse order relation of unit fractions in my Grade 5 mathematics classroom. Much research has identified fractions as a problematic concept to teach in primary schools. Curriculum expectations of mathematics and music, as well as prior research, recognise a link between these two subject areas. Based on these connections between mathematics and music, I make the case for further research into practical ways in which music and mathematics can be integrated to support teaching and learning in the South African context. This study is located within a qualitative and interpretive framework. The concepts of integration, learning style theory, Gardner’s multiple intelligences and Bresler’s styles of arts integration guide the research. I made use of practical and theoretical activities relating to note values in music. I explored these strategies and the use of learning support materials through an action research case study, in which I engaged in cycles of trialing, reflecting, adjusting and re-trialing within the ‘case’ of my own mathematics class. Data sources comprised of my reflective journal, learner feedback, video- and audio-recorded lessons, examples of learners’ work and interviews with critical peers who observed critical moments from the video recordings. I was guided through the analysis phase by two analytical frameworks: Karsenty and Arcavi’s Six Lense Framework (SLF) and Adler and Ronda’s Mathematics Discourse in Instruction (MDI) framework which I adapted. Using three key lessons, I provide detailed descriptions of how the lessons progressed and then identify and discuss some of the key findings and recurring themes in relation to my study’s research question and goals. Through this process, I show that my integration of mathematics and musical activities helped promote active engagement amongst learners and provided them with co-equivalent opportunities to appreciate the importance of note values in music, and relate this back to understandings around the inverse order relation of unit fractions.
- Full Text:
- Date Issued: 2020
- Authors: Lovemore, Tarryn Shirley
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa -- Case studies , Interdisciplinary approach in education -- South Africa -- Case studies , Music -- Study and teaching (Elementary) -- South Africa -- Case studies , Music -- Mathematics , Musical notation -- Study and teaching (Elementary)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142431 , vital:38079
- Description: This research study explored how the use of musical activities, specifically based on note values, might enrich my teaching around the inverse order relation of unit fractions in my Grade 5 mathematics classroom. Much research has identified fractions as a problematic concept to teach in primary schools. Curriculum expectations of mathematics and music, as well as prior research, recognise a link between these two subject areas. Based on these connections between mathematics and music, I make the case for further research into practical ways in which music and mathematics can be integrated to support teaching and learning in the South African context. This study is located within a qualitative and interpretive framework. The concepts of integration, learning style theory, Gardner’s multiple intelligences and Bresler’s styles of arts integration guide the research. I made use of practical and theoretical activities relating to note values in music. I explored these strategies and the use of learning support materials through an action research case study, in which I engaged in cycles of trialing, reflecting, adjusting and re-trialing within the ‘case’ of my own mathematics class. Data sources comprised of my reflective journal, learner feedback, video- and audio-recorded lessons, examples of learners’ work and interviews with critical peers who observed critical moments from the video recordings. I was guided through the analysis phase by two analytical frameworks: Karsenty and Arcavi’s Six Lense Framework (SLF) and Adler and Ronda’s Mathematics Discourse in Instruction (MDI) framework which I adapted. Using three key lessons, I provide detailed descriptions of how the lessons progressed and then identify and discuss some of the key findings and recurring themes in relation to my study’s research question and goals. Through this process, I show that my integration of mathematics and musical activities helped promote active engagement amongst learners and provided them with co-equivalent opportunities to appreciate the importance of note values in music, and relate this back to understandings around the inverse order relation of unit fractions.
- Full Text:
- Date Issued: 2020
Evaluation of an NADPH-dependent assay for inhibition screening of Salmonella enterica DOXP Reguctoisomerase for identification of novel drug hit compounds
- Authors: Ngcongco, Khanyisile
- Date: 2020
- Subjects: 1-Deoxy-D-xylulose 5-phosphate , Antibiotics , Drug development , Salmonella , Enterobacteriaceae , Vaccines , Plasmodium falciparum , Mycobacterium tuberculosis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167132 , vital:41440
- Description: Invasive non-typhoidal Salmonella, caused by the intracellular pathogen Salmonella enterica, has emerged as a major cause of bloodstream infections. It remains a neglected infection responsible for many deaths in Africa, as it fails to receive the level of support that is given to most better known infections. There are currently no vaccines against invasive non-typhoidal Salmonella. First-line antibiotics have been used for treatment, however, the rise in the resistance of the bacteria against these antibiotics has made treatment of invasive salmonellosis into a clinical problem. Therefore, the discovery of new compounds for the development of antibiotic drugs is required. Central metabolic pathways can be a useful source for identifying drug targets and among these is the non-mevalonate pathway, one of the pathways used for the biosynthesis of isoprenoid precursors. The second step of the non-mevalonate pathway involves the NADPH-dependent reduction of 1-deoxy-D-xylulose 5-phosphate (DOXP) into 2-C-methyl-D-erythritol 4-phosphate (MEP). 1-Deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase plays a vital role in the catalysis of this reaction and requires NADPH and divalent metal cations as co-factors for its activity. In this investigation recombinant DOXP reductoisomerase from Salmonella enterica, Plasmodium falciparum and Mycobacterium tuberculosis were biochemically characterized as potential targets for developing drugs that could be used as treatment of the disease. The expression and nickel-chelate affinity purification of S. enterica DOXP reductoisomerase in a fully functional native state was successfully achieved. However, the expression and purification of P. falciparum DXR and M. tuberculosis DXR was unsuccessful due to the formation of insoluble inclusion bodies. Although alternative purification strategies were explored, including dialysis and slow dilution, these proteins remained insoluble, making their functional analysis not possible. An NADPH-dependent enzyme assay was used to determine the activity of S. enterica DXR. This assay monitors the reduction of DOXP to MEP by measuring the absorbance at 340 nm, which reflects the concentration of NADPH. An alternative assay, resazurin reduction, which monitors the NADPH-dependent reduction of resazurin to resorufin, was explored for detecting enzyme activity. The recombinant S. enterica DOXP reductoisomerase had a specific activity of 0.126 ± 0.0014 μmol/min/mg protein and a Km and Vmax of 881 μM and 0.249 μmol/min/mg respectively. FR900098, a derivative of fosmidomycin, is a well-known inhibitor of DXR, however, the sensitivity of S. enterica DXR towards FR900098 has not yet been reported. The NADPH dependent enzyme and resazurin reduction assays were used to determine whether FR900098 has enzyme inhibitory effects against S. enterica DXR. Upon confirming that FR900098 is able to inhibit S. enterica DXR, FR900098 was used as a control compound in the screening of novel compounds. The S. enterica DXR enzyme was screened for inhibition by the collection of compounds from the Pathogen Box. Compounds that exhibited the desired inhibitory activity, referred to as ‘hits’ were selected for further investigation. These hits were confirmed using the NADPH-dependent enzyme assay, resulting in the identification of two different DXR inhibitor compounds, MMV002816, also known as diethylcarbamazine, and MMV228911. The inhibitory concentration (IC50) values of FR900098, MMV002816 and MMV228911 against S. enterica DXR were 1.038 μM, 2.173 μM and 6.861 μM respectively. The binding mode of these compounds to S. enterica DXR could lead to the discovery of novel druggable sites on the enzyme and stimulate the development of new antibiotics that can be used for treating Salmonella infections.
- Full Text:
- Date Issued: 2020
- Authors: Ngcongco, Khanyisile
- Date: 2020
- Subjects: 1-Deoxy-D-xylulose 5-phosphate , Antibiotics , Drug development , Salmonella , Enterobacteriaceae , Vaccines , Plasmodium falciparum , Mycobacterium tuberculosis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167132 , vital:41440
- Description: Invasive non-typhoidal Salmonella, caused by the intracellular pathogen Salmonella enterica, has emerged as a major cause of bloodstream infections. It remains a neglected infection responsible for many deaths in Africa, as it fails to receive the level of support that is given to most better known infections. There are currently no vaccines against invasive non-typhoidal Salmonella. First-line antibiotics have been used for treatment, however, the rise in the resistance of the bacteria against these antibiotics has made treatment of invasive salmonellosis into a clinical problem. Therefore, the discovery of new compounds for the development of antibiotic drugs is required. Central metabolic pathways can be a useful source for identifying drug targets and among these is the non-mevalonate pathway, one of the pathways used for the biosynthesis of isoprenoid precursors. The second step of the non-mevalonate pathway involves the NADPH-dependent reduction of 1-deoxy-D-xylulose 5-phosphate (DOXP) into 2-C-methyl-D-erythritol 4-phosphate (MEP). 1-Deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase plays a vital role in the catalysis of this reaction and requires NADPH and divalent metal cations as co-factors for its activity. In this investigation recombinant DOXP reductoisomerase from Salmonella enterica, Plasmodium falciparum and Mycobacterium tuberculosis were biochemically characterized as potential targets for developing drugs that could be used as treatment of the disease. The expression and nickel-chelate affinity purification of S. enterica DOXP reductoisomerase in a fully functional native state was successfully achieved. However, the expression and purification of P. falciparum DXR and M. tuberculosis DXR was unsuccessful due to the formation of insoluble inclusion bodies. Although alternative purification strategies were explored, including dialysis and slow dilution, these proteins remained insoluble, making their functional analysis not possible. An NADPH-dependent enzyme assay was used to determine the activity of S. enterica DXR. This assay monitors the reduction of DOXP to MEP by measuring the absorbance at 340 nm, which reflects the concentration of NADPH. An alternative assay, resazurin reduction, which monitors the NADPH-dependent reduction of resazurin to resorufin, was explored for detecting enzyme activity. The recombinant S. enterica DOXP reductoisomerase had a specific activity of 0.126 ± 0.0014 μmol/min/mg protein and a Km and Vmax of 881 μM and 0.249 μmol/min/mg respectively. FR900098, a derivative of fosmidomycin, is a well-known inhibitor of DXR, however, the sensitivity of S. enterica DXR towards FR900098 has not yet been reported. The NADPH dependent enzyme and resazurin reduction assays were used to determine whether FR900098 has enzyme inhibitory effects against S. enterica DXR. Upon confirming that FR900098 is able to inhibit S. enterica DXR, FR900098 was used as a control compound in the screening of novel compounds. The S. enterica DXR enzyme was screened for inhibition by the collection of compounds from the Pathogen Box. Compounds that exhibited the desired inhibitory activity, referred to as ‘hits’ were selected for further investigation. These hits were confirmed using the NADPH-dependent enzyme assay, resulting in the identification of two different DXR inhibitor compounds, MMV002816, also known as diethylcarbamazine, and MMV228911. The inhibitory concentration (IC50) values of FR900098, MMV002816 and MMV228911 against S. enterica DXR were 1.038 μM, 2.173 μM and 6.861 μM respectively. The binding mode of these compounds to S. enterica DXR could lead to the discovery of novel druggable sites on the enzyme and stimulate the development of new antibiotics that can be used for treating Salmonella infections.
- Full Text:
- Date Issued: 2020