Observations of cosmic re-ionisation with the Hydrogen Epoch of Reionization Array: simulations of closure phase spectra
- Authors: Charles, Ntsikelelo
- Date: 2021-04
- Subjects: Epoch of reionization , Space interferometry , Astronomy -- Observations , Closure phase spectra
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/174470 , vital:42480
- Description: The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionisation. It has driven the construction of the new generation of low frequency radio interferometric arrays, including the Hydrogen Epoch of Reionization Array (HERA). The main difficulty in measuring the 21 cm signal is the presence of bright foregrounds that require very accurate interferometric calibration. Thyagarajan et al. (2018) proposed the use of closure phase quantities as a means to detect the 21 cm signal, which has the advantage of being independent (to first order) from calibration errors and therefore, bypasses the need for accurate calibration. Closure phases are, however, affected by so-called direction dependent effects, e.g. the fact that the dishes - or antennas - of an interferometric array are not identical to each other and , therefore, yield different antenna primary beam responses. In this thesis, we investigate the impact of direction dependent effects on closure quantities and simulate the impact that primary antenna beams affected by mutual coupling have on the foreground closure phase and its power spectrum i.e. the power spectrum of the bispectrum phase (Thyagarajan et al., 2020). Our simulations show that primary beams affected by mutual coupling lead to an overall leakage of foreground power in the so-called EoR window, i.e. power from smooth-spectrum foregrounds is confined to low k modes. We quantified this effect and found that the leakage is up to ~ 8 orders magnitude higher than the case of an ideal beam at kǁ > 0:5 h Mpc-1. We also found that the foreground leakage is worse when edge antennas are included, as they have a more different primary beam compared to antennas at the centre of the array. The leakage magnitude is worse when bright foregrounds appear in the antenna sidelobes, as expected. Our simulations provide a useful framework to interpret observations and assess which power spectrum region is expected to be most contaminated by foreground power leakage.
- Full Text:
- Date Issued: 2021-04
- Authors: Charles, Ntsikelelo
- Date: 2021-04
- Subjects: Epoch of reionization , Space interferometry , Astronomy -- Observations , Closure phase spectra
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/174470 , vital:42480
- Description: The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionisation. It has driven the construction of the new generation of low frequency radio interferometric arrays, including the Hydrogen Epoch of Reionization Array (HERA). The main difficulty in measuring the 21 cm signal is the presence of bright foregrounds that require very accurate interferometric calibration. Thyagarajan et al. (2018) proposed the use of closure phase quantities as a means to detect the 21 cm signal, which has the advantage of being independent (to first order) from calibration errors and therefore, bypasses the need for accurate calibration. Closure phases are, however, affected by so-called direction dependent effects, e.g. the fact that the dishes - or antennas - of an interferometric array are not identical to each other and , therefore, yield different antenna primary beam responses. In this thesis, we investigate the impact of direction dependent effects on closure quantities and simulate the impact that primary antenna beams affected by mutual coupling have on the foreground closure phase and its power spectrum i.e. the power spectrum of the bispectrum phase (Thyagarajan et al., 2020). Our simulations show that primary beams affected by mutual coupling lead to an overall leakage of foreground power in the so-called EoR window, i.e. power from smooth-spectrum foregrounds is confined to low k modes. We quantified this effect and found that the leakage is up to ~ 8 orders magnitude higher than the case of an ideal beam at kǁ > 0:5 h Mpc-1. We also found that the foreground leakage is worse when edge antennas are included, as they have a more different primary beam compared to antennas at the centre of the array. The leakage magnitude is worse when bright foregrounds appear in the antenna sidelobes, as expected. Our simulations provide a useful framework to interpret observations and assess which power spectrum region is expected to be most contaminated by foreground power leakage.
- Full Text:
- Date Issued: 2021-04
Nutrient impacts on grasses and legumes growing in communal pasture soil in relation to mycorrhizal activity
- Authors: Mkile, Zolani
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164512 , vital:41125 , doi:10.21504/10962/164512
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Mkile, Zolani
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164512 , vital:41125 , doi:10.21504/10962/164512
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
Night-time gravity waves detected with multi-frequency airglow imager
- Authors: Machubeng, Karabo Pebane
- Date: 2021-04
- Subjects: Gravity waves , Airglow , Gravity waves -- Seasonal variations , All Sky Imager
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178341 , vital:42931
- Description: This thesis shows the statistics of atmospheric gravity waves (AGWs) observed in the OI emission 557.7 nm at _97 km altitude using an all-sky imager based in Sutherland, South Africa (32.37_ S, 20.81_ E) in the year 2017. The wavelengths were determined using the propagation vector method, velocity was determined using the cross correlation of 1D FFT and the period was determined using the equation that relates wavelength and velocity. It was found that the horizontal wavelength in summer was almost evenly distributed between 10 and 40 km and for autumn, winter and spring were mostly between 10 and 30 km. The favoured speeds were between 40 and 50 m/s in autumn, as well as 30 and 50 m/s in summer, but the AGWs in winter had a bimodal speed distribution of 20 - 40 and 50 - 70 m/s. The majority of periods observed in all seasons were less than 20 minutes with a dominant peak of 5 - 10 minutes in autumn and spring. There was no favoured propagation direction for spring, but AGWs favoured a southeastward propagation in summer, and a southward propagation in autumn and winter. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Machubeng, Karabo Pebane
- Date: 2021-04
- Subjects: Gravity waves , Airglow , Gravity waves -- Seasonal variations , All Sky Imager
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178341 , vital:42931
- Description: This thesis shows the statistics of atmospheric gravity waves (AGWs) observed in the OI emission 557.7 nm at _97 km altitude using an all-sky imager based in Sutherland, South Africa (32.37_ S, 20.81_ E) in the year 2017. The wavelengths were determined using the propagation vector method, velocity was determined using the cross correlation of 1D FFT and the period was determined using the equation that relates wavelength and velocity. It was found that the horizontal wavelength in summer was almost evenly distributed between 10 and 40 km and for autumn, winter and spring were mostly between 10 and 30 km. The favoured speeds were between 40 and 50 m/s in autumn, as well as 30 and 50 m/s in summer, but the AGWs in winter had a bimodal speed distribution of 20 - 40 and 50 - 70 m/s. The majority of periods observed in all seasons were less than 20 minutes with a dominant peak of 5 - 10 minutes in autumn and spring. There was no favoured propagation direction for spring, but AGWs favoured a southeastward propagation in summer, and a southward propagation in autumn and winter. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
- Date Issued: 2021-04
Ndiyazi ukuba ndiza kufa njani : ingqokelela yemibongo
- Authors: Mdliva, Mqhubi Given
- Date: 2021-04
- Subjects: Creative writing (Higher education) -- South Africa , Xhosa poetry -- 21st century , Xhosa poetry -- History and criticism , Diaries -- Authorship , Xhosa fiction -- 21st century
- Language: Xhosa
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/178295 , vital:42928
- Description: Le mibongo inyathela kwizinto ezitsarhayo; ukufa, ukukhula kweziganeko ezingobundlobongela obuphathelele kwezesondo nesini, kubulawa abantwana namanina ngamadoda norhwaphilizo olugqugqisayo. Lo msebenzi uphonononga ukwavavanya ukusetyenziswa kweempawu zokubhala kungalandelwa miqathango yokubhala koko kusetyenziswa ezi mpawu njengezixhobo zokuphuhlisa iimvakalelo zembongi. Ezi mpawu ziquka iidesh, iikholoni, iisemikholoni ukuqelelaniswa kwamagama kukwashiywa nezikhewu phakathi kwamagama kukhokelwa ngumoya wemibongo. Oku kubangele ukuba le mibongo ibe nezakhiwo ezahlukileyo nezingaqhelekanga kubhalo lwesiXhosa. Oko kukuthi, lo msebenzi utyebisa uncwadi lwesiXhosa ngokukwandisa kule ndlela ingaqhelekanga yokubhala. Umsebenzi kaSt E.P. Yako ube nefuthe kakhulu kulo msebenzi, ngakumbi indlela alusebenzise ngayo ulwimi oluteketeke zizafobe nemifanekiso ukubhala imibongo njengoko enzile kumbongo othi, Izibongo zikaMhlekazi uArchie Sandile. Kumbhali uMarina Tsvetaete kubolekwe indlela ayisebenzise ngayo imifanekiso kumbongo osihloko sithi, Poems for Block kuba udubula ngegama uthi thaa umfanekiso kwingqondo yomfundi. Isimbo sokuyila isakhiwo sombongo sikaSimphiwe Nolutshungu naso sibe nefuthe kule mibongo, kwaye le thisisi yandisa apho lo kaNolutshungu aphele khona ngakumbi kwindlela asebenzise ngayo iimpawu zokubhala. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Mdliva, Mqhubi Given
- Date: 2021-04
- Subjects: Creative writing (Higher education) -- South Africa , Xhosa poetry -- 21st century , Xhosa poetry -- History and criticism , Diaries -- Authorship , Xhosa fiction -- 21st century
- Language: Xhosa
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/178295 , vital:42928
- Description: Le mibongo inyathela kwizinto ezitsarhayo; ukufa, ukukhula kweziganeko ezingobundlobongela obuphathelele kwezesondo nesini, kubulawa abantwana namanina ngamadoda norhwaphilizo olugqugqisayo. Lo msebenzi uphonononga ukwavavanya ukusetyenziswa kweempawu zokubhala kungalandelwa miqathango yokubhala koko kusetyenziswa ezi mpawu njengezixhobo zokuphuhlisa iimvakalelo zembongi. Ezi mpawu ziquka iidesh, iikholoni, iisemikholoni ukuqelelaniswa kwamagama kukwashiywa nezikhewu phakathi kwamagama kukhokelwa ngumoya wemibongo. Oku kubangele ukuba le mibongo ibe nezakhiwo ezahlukileyo nezingaqhelekanga kubhalo lwesiXhosa. Oko kukuthi, lo msebenzi utyebisa uncwadi lwesiXhosa ngokukwandisa kule ndlela ingaqhelekanga yokubhala. Umsebenzi kaSt E.P. Yako ube nefuthe kakhulu kulo msebenzi, ngakumbi indlela alusebenzise ngayo ulwimi oluteketeke zizafobe nemifanekiso ukubhala imibongo njengoko enzile kumbongo othi, Izibongo zikaMhlekazi uArchie Sandile. Kumbhali uMarina Tsvetaete kubolekwe indlela ayisebenzise ngayo imifanekiso kumbongo osihloko sithi, Poems for Block kuba udubula ngegama uthi thaa umfanekiso kwingqondo yomfundi. Isimbo sokuyila isakhiwo sombongo sikaSimphiwe Nolutshungu naso sibe nefuthe kule mibongo, kwaye le thisisi yandisa apho lo kaNolutshungu aphele khona ngakumbi kwindlela asebenzise ngayo iimpawu zokubhala. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-04
Nature conservation, protected areas and local communities : the Tsitsikamma National Park
- Authors: Le Fleur, Yvette Adele
- Date: 2021-04
- Subjects: National parks and reserves -- South Africa -- Eastern Cape , Protected areas -- Management , Programme of Work on Protected Areas , Human ecology -- South Africa -- Tsitsikamma , Nature conservation -- Citizen participation
- Language: English
- Type: thesis , text , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/177247 , vital:42803
- Description: Since the twentieth century, protected areas, usually in the form of nature reserves or national parks, have become increasingly more dominant as an international conservation strategy. An important factor in protected area management is the relationship between protected areas and its surrounding communities. Historically, the fortress conservation model based on the exclusion of human use and occupation prevailed in relation to protected areas. It is known that this approach brought with it many social and environmental injustices to local communities living in or adjacent to parks. However, a shift in conservation thinking occurred towards the end of the twentieth century, where it has increasingly been advocated for a more participatory approach in protected area management. South Africa has signed the international Convention on Biological Diversity that promotes a participatory approach to nature conservation, which is also reflected in the country’s national laws and policies. In relation to the literature and the lens of political ecology, this thesis sets out to assess in what ways and to what extent the participatory approach has been embraced by South Africa’s conservation authorities. As a case study, it looks at the Tsitsikamma National P ark ( incorporated into the larger Garden Route National Park). In order to get insight on h ow the participatory approach plays itself out at the T NP and what the nature of local communities’ relationship with the park is, this study looks at the aspects of (1) local communities’ socio-economic conditions, (2) their relationship with their natural environment, (3) their perception of nature conservation and (4) their perception of tourism. Then, taking all these aspects into account, (5) how local communities, in general, perceive their relationship with the p ark and its authorities. This study looked at the communities of Kurland, Nature’s Valley, Covie and Storms River. It shows in concurrence with other studies, that despite progressive laws and policies that express the intention of the South African state and SANParks to embrace the participatory approach, its implementation o n t he g round is riddled with challenges. , Thesis (MSocSc) -- Faculty of Humanities, Athropology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Le Fleur, Yvette Adele
- Date: 2021-04
- Subjects: National parks and reserves -- South Africa -- Eastern Cape , Protected areas -- Management , Programme of Work on Protected Areas , Human ecology -- South Africa -- Tsitsikamma , Nature conservation -- Citizen participation
- Language: English
- Type: thesis , text , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/177247 , vital:42803
- Description: Since the twentieth century, protected areas, usually in the form of nature reserves or national parks, have become increasingly more dominant as an international conservation strategy. An important factor in protected area management is the relationship between protected areas and its surrounding communities. Historically, the fortress conservation model based on the exclusion of human use and occupation prevailed in relation to protected areas. It is known that this approach brought with it many social and environmental injustices to local communities living in or adjacent to parks. However, a shift in conservation thinking occurred towards the end of the twentieth century, where it has increasingly been advocated for a more participatory approach in protected area management. South Africa has signed the international Convention on Biological Diversity that promotes a participatory approach to nature conservation, which is also reflected in the country’s national laws and policies. In relation to the literature and the lens of political ecology, this thesis sets out to assess in what ways and to what extent the participatory approach has been embraced by South Africa’s conservation authorities. As a case study, it looks at the Tsitsikamma National P ark ( incorporated into the larger Garden Route National Park). In order to get insight on h ow the participatory approach plays itself out at the T NP and what the nature of local communities’ relationship with the park is, this study looks at the aspects of (1) local communities’ socio-economic conditions, (2) their relationship with their natural environment, (3) their perception of nature conservation and (4) their perception of tourism. Then, taking all these aspects into account, (5) how local communities, in general, perceive their relationship with the p ark and its authorities. This study looked at the communities of Kurland, Nature’s Valley, Covie and Storms River. It shows in concurrence with other studies, that despite progressive laws and policies that express the intention of the South African state and SANParks to embrace the participatory approach, its implementation o n t he g round is riddled with challenges. , Thesis (MSocSc) -- Faculty of Humanities, Athropology, 2021
- Full Text:
- Date Issued: 2021-04
Multiplexed Mass Spectrometry: Single, On-Bead, Detection Analysis Using MALDI-TOF MS
- Authors: Twala, Busisiwe Victoria
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164693 , vital:41155 , doi:10.21504/10962/164693
- Description: Thesis (PhD)--Rhodes University, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Twala, Busisiwe Victoria
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164693 , vital:41155 , doi:10.21504/10962/164693
- Description: Thesis (PhD)--Rhodes University, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
Motivation to learn science and make sense of the concept of malleability through the traditional blast furnace in a grade 9 Physical Science class
- Authors: Kudumo, Wilfred Peter
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia -- Kavango West , Metals -- Effect of high temperatures on , Blast furnaces , Ethnoscience -- Namibia -- Kavango West , Ubuntu (Philosophy) , Culturally relevant pedagogy , Motivation in education -- Namibia -- Kavango West , Continuity Argumentative Theory (CAT)
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177262 , vital:42804
- Description: The current situation of teaching and learning science in Namibia is of great concern since it does not seem to take into consideration learners’ socio-cultural backgrounds. As a result, learners are finding that science is not relevant to their everyday life experiences and hence are not motivated to learn it. This is compounded in part by the fact that the Namibian curriculum seems to be silent on how science teachers should include learners’ socio-cultural backgrounds, for example, local or indigenous knowledge in their teaching repertoires. It is against this background that in this study I explored how mobilising the cultural practice of a traditional blast furnace (mudukuto) as an approach enables and/or constrains learners’ motivation to learn science and make sense of the concept of malleability. This is a qualitative case study underpinned by a combination of interpretive and Ubuntu paradigms. It was carried out in a rural school in Namibia, Kavango West Region, where I am currently teaching. The participants in the study were grade 9 learners and one expert community member. Focus group interviews, participatory observation, learners’ reflections, and stimulated recall interviews were used to gather qualitative data. Vygotsky’s socio-cultural theory was used as a theoretical framework and Ogunniyi`s Continuity Argumentative Theory (CAT) was used as analytical framework or lens to analyse the data. A thematic approach to analyse data was employed. That is, qualitative data were analysed inductively to come up with sub-themes and themes. The findings of the study revealed that the traditional furnace motivated the learners involved in this study to learn science and learners were able to extract science concepts on malleability from the traditional practice. The implication for this study is that when science is related to learners’ daily life or real-world experiences, they are enabled to bridge the gap from what they learn at home or in the community with school science. The study thus recommends that teachers should make an effort to integrate local or indigenous knowledge and practices to make science accessible and relevant in their classrooms. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Kudumo, Wilfred Peter
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia -- Kavango West , Metals -- Effect of high temperatures on , Blast furnaces , Ethnoscience -- Namibia -- Kavango West , Ubuntu (Philosophy) , Culturally relevant pedagogy , Motivation in education -- Namibia -- Kavango West , Continuity Argumentative Theory (CAT)
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177262 , vital:42804
- Description: The current situation of teaching and learning science in Namibia is of great concern since it does not seem to take into consideration learners’ socio-cultural backgrounds. As a result, learners are finding that science is not relevant to their everyday life experiences and hence are not motivated to learn it. This is compounded in part by the fact that the Namibian curriculum seems to be silent on how science teachers should include learners’ socio-cultural backgrounds, for example, local or indigenous knowledge in their teaching repertoires. It is against this background that in this study I explored how mobilising the cultural practice of a traditional blast furnace (mudukuto) as an approach enables and/or constrains learners’ motivation to learn science and make sense of the concept of malleability. This is a qualitative case study underpinned by a combination of interpretive and Ubuntu paradigms. It was carried out in a rural school in Namibia, Kavango West Region, where I am currently teaching. The participants in the study were grade 9 learners and one expert community member. Focus group interviews, participatory observation, learners’ reflections, and stimulated recall interviews were used to gather qualitative data. Vygotsky’s socio-cultural theory was used as a theoretical framework and Ogunniyi`s Continuity Argumentative Theory (CAT) was used as analytical framework or lens to analyse the data. A thematic approach to analyse data was employed. That is, qualitative data were analysed inductively to come up with sub-themes and themes. The findings of the study revealed that the traditional furnace motivated the learners involved in this study to learn science and learners were able to extract science concepts on malleability from the traditional practice. The implication for this study is that when science is related to learners’ daily life or real-world experiences, they are enabled to bridge the gap from what they learn at home or in the community with school science. The study thus recommends that teachers should make an effort to integrate local or indigenous knowledge and practices to make science accessible and relevant in their classrooms. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-04
Molecular and morphological approaches reveal hidden diversity in the genus hippopotamyrus pappenheim, 1906 (teleostei: mormyridae) in southern Africa
- Authors: Mutizwa, Tadiwa, Isaac
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164546 , vital:41128
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Icthyology and Fisheries Science, 2020
- Full Text:
- Date Issued: 2020
- Authors: Mutizwa, Tadiwa, Isaac
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164546 , vital:41128
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Icthyology and Fisheries Science, 2020
- Full Text:
- Date Issued: 2020
Mapping the pyrroloiminoquinone diversity produced by latrunculid sponges using tandem mass spectrometry-driven molecular networking
- Authors: Kalinski, Jarmo-Charles
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178468 , vital:42942
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Kalinski, Jarmo-Charles
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178468 , vital:42942
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
Making Sense of Barkhuizen 2 : An Investigation into the Public Policy Defence of ‘Unfair Enforcement’ in South African Law, with Reference to the Law on Covenants in Restraint of Trade
- Authors: Moroeng, Tsukudu Kenyatta
- Date: 2021-04
- Subjects: Restraint of trade -- South Africa , Public policy (Law) -- South Africa , Contracts (Roman-Dutch law) , Customary law -- South Africa , Barkhuizen v Napier
- Language: English
- Type: thesis , text , Masters , LLM
- Identifier: http://hdl.handle.net/10962/177147 , vital:42794
- Description: This thesis investigates the application of the public policy test for determining the enforceability of a valid contractual clause established in Barkhuizen v Napier. After analysing the historical development of the application of the doctrine of public policy, the study examines the conceptualisation and application of the public policy test in the leading cases in South Africa. The study then provides an analysis of the recent judgment of Beadica 231 CC and Others v Trustees for the time being of the Oregon Trust and Others, which outlined the current legal position on the proper constitutional approach to the judicial enforcement of valid contractual clauses. The study argues that, although the Constitutional Court in Beadica provided some clarity on what public policy is in modern South African law, it did not, from a practical point of view, set out the method that should be used to adjudicate such cases. The study thereafter suggests that, to address this issue, our courts should consider developing a methodological approach to measuring public policy in unfair enforcement cases. To support this proposition, the study examines the law on determining the enforcement of restraint of trade agreements. It is argued that, within that context, the courts have formulated a methodological approach in the form of a list of standard questions that a judge should ask when determining the enforceability of a restraint clause. The thesis then closes with a case study, using guidelines established from the approach in restraint cases, to illustrate how the proposed guideline may be formulated, and how it could be applied in general unfair enforcement cases. The thesis argues that a practical guide of this nature would serve as a useful tool for judges to use when faced with a claim relating to the unfair enforcement of a valid clause other than a restraint clause, and would thus ensure consistency in contractual enforcement analysis in South Africa. , Thesis (LLM) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Moroeng, Tsukudu Kenyatta
- Date: 2021-04
- Subjects: Restraint of trade -- South Africa , Public policy (Law) -- South Africa , Contracts (Roman-Dutch law) , Customary law -- South Africa , Barkhuizen v Napier
- Language: English
- Type: thesis , text , Masters , LLM
- Identifier: http://hdl.handle.net/10962/177147 , vital:42794
- Description: This thesis investigates the application of the public policy test for determining the enforceability of a valid contractual clause established in Barkhuizen v Napier. After analysing the historical development of the application of the doctrine of public policy, the study examines the conceptualisation and application of the public policy test in the leading cases in South Africa. The study then provides an analysis of the recent judgment of Beadica 231 CC and Others v Trustees for the time being of the Oregon Trust and Others, which outlined the current legal position on the proper constitutional approach to the judicial enforcement of valid contractual clauses. The study argues that, although the Constitutional Court in Beadica provided some clarity on what public policy is in modern South African law, it did not, from a practical point of view, set out the method that should be used to adjudicate such cases. The study thereafter suggests that, to address this issue, our courts should consider developing a methodological approach to measuring public policy in unfair enforcement cases. To support this proposition, the study examines the law on determining the enforcement of restraint of trade agreements. It is argued that, within that context, the courts have formulated a methodological approach in the form of a list of standard questions that a judge should ask when determining the enforceability of a restraint clause. The thesis then closes with a case study, using guidelines established from the approach in restraint cases, to illustrate how the proposed guideline may be formulated, and how it could be applied in general unfair enforcement cases. The thesis argues that a practical guide of this nature would serve as a useful tool for judges to use when faced with a claim relating to the unfair enforcement of a valid clause other than a restraint clause, and would thus ensure consistency in contractual enforcement analysis in South Africa. , Thesis (LLM) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-04
Long Waves of Strikes in South Africa: 1886–2019
- Authors: Cottle, Eddie
- Date: 2020
- Subjects: Strikes and lockouts South Africa , Long waves (Economics) South Africa , Business cycles South Africa , Industrial mobilization South Africa , Collective bargaining South Africa , Institutionalisation , Labor unions South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163228 , vital:41020 , doi:10.21504/10962/163228
- Description: Thesis (PhD)--Rhodes University, Faculty of Humanities, Institute for Social and Economic Research (ISER), 2020.
- Full Text:
- Date Issued: 2020
- Authors: Cottle, Eddie
- Date: 2020
- Subjects: Strikes and lockouts South Africa , Long waves (Economics) South Africa , Business cycles South Africa , Industrial mobilization South Africa , Collective bargaining South Africa , Institutionalisation , Labor unions South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163228 , vital:41020 , doi:10.21504/10962/163228
- Description: Thesis (PhD)--Rhodes University, Faculty of Humanities, Institute for Social and Economic Research (ISER), 2020.
- Full Text:
- Date Issued: 2020
Livelihood implications of a possible Ramsar declaration of the Swartkops estuary, Eastern Cape, South Africa
- Authors: Vembo, Glen Muchengeti
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164715 , vital:41157
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Environmental Science, 2020
- Full Text:
- Date Issued: 2020
- Authors: Vembo, Glen Muchengeti
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164715 , vital:41157
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Environmental Science, 2020
- Full Text:
- Date Issued: 2020
Larval fish dynamics within the coastal nearshore of the Eastern Cape, South Africa
- Authors: Sotshongaye, Oko
- Date: 2021-04
- Subjects: Fishes -- Larvae -- South Africa -- Eastern Cape , Fishes -- Larvae -- Development -- South Africa -- Eastern Cape , Fishes -- Larvae -- Ecology -- South Africa -- Eastern Cape , Coastal ecology -- South Africa -- Eastern Cape , Fishes -- Larvae -- Dispersal -- South Africa -- Eastern Cape
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/176977 , vital:42776
- Description: The coastal nearshore is important for the early development of fishes as it is used for spawning and/or as a nursery. One of the central concerns in coastal ecology is understanding the role of the nearshore for larvae, ultimately providing key knowledge on population dynamics and hence helping in making decisions pertaining to conservation and resource management. The aim of this study was to investigate the alongshore and cross-shore distribution of larval fishes and the links to the physio-chemical conditions (including prevailing winds) and hydrodynamics in the region of Algoa Bay, situated on the south east coast in the warm temperate region of South Africa. Fish larvae were sampled at nine sites for the first component of the study (January 2016 –March 2017) and at four sites for the second component (November 2019), near the surface and bottom (15-50 m) of the water column as well as at two different distances from shore (~400 m/~3 km) using a set of bongo plankton nets towed behind a boat. Environmental data were simultaneously collected using and acoustic Doppler current profiler (ADCP) and conductivity, temperature, depth (CTD) profiler. Larval fish abundance generally decreased with increasing distance from the shore, however, this varied in space and time, with some larval species recorded in high abundances offshore. Close inshore the larvae of coastal fish species producing benthic eggs (CBE) including the Blenniidae and Gobiesocidae mostly dominated, while offshore the larvae of coastal fish species producing pelagic eggs (CPE) i.e. Sparidae and Cynoglossidae, as well as pelagic fish species producing pelagic eggs (PPE) i.e. Clupeidae and Engraulidae mostly dominated. Vertical distribution of larvae differed according to taxon, with the Callionymidae (CPE), Cynoglossidae and Gobiesocidae occurring at high densities at the bottom of the water column, while the Blenniidae dominated near the surface. Fluorescence, temperature and salinity varied with depth (surface/bottom), being particularly high at the surface; currents moved faster at the surface than the bottom of the water column. Increased abundances of larval fishes were evident after upwelling events (associated with easterly winds) in the Bay, while during downwelling (associated with westerly winds), low densities were generally recorded, except for the sites situated near headlands/capes where there were higher densities of fish larvae during downwelling events. Overall, the results of this study suggest that spawning mode of the adults, oceanography and environmental conditions coupled with what is known of the behaviour of fish larvae, were important in shaping the larval fish community of the Algoa Bay region. These results highlight the importance of incorporating multiple biological (developmental stage, reproductive mode, species) and physical (currents, fluorescence, wind-driven up/down-welling) factors when addressing the mechanims of transport of larval fish in the coastal nearshore. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Sotshongaye, Oko
- Date: 2021-04
- Subjects: Fishes -- Larvae -- South Africa -- Eastern Cape , Fishes -- Larvae -- Development -- South Africa -- Eastern Cape , Fishes -- Larvae -- Ecology -- South Africa -- Eastern Cape , Coastal ecology -- South Africa -- Eastern Cape , Fishes -- Larvae -- Dispersal -- South Africa -- Eastern Cape
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/176977 , vital:42776
- Description: The coastal nearshore is important for the early development of fishes as it is used for spawning and/or as a nursery. One of the central concerns in coastal ecology is understanding the role of the nearshore for larvae, ultimately providing key knowledge on population dynamics and hence helping in making decisions pertaining to conservation and resource management. The aim of this study was to investigate the alongshore and cross-shore distribution of larval fishes and the links to the physio-chemical conditions (including prevailing winds) and hydrodynamics in the region of Algoa Bay, situated on the south east coast in the warm temperate region of South Africa. Fish larvae were sampled at nine sites for the first component of the study (January 2016 –March 2017) and at four sites for the second component (November 2019), near the surface and bottom (15-50 m) of the water column as well as at two different distances from shore (~400 m/~3 km) using a set of bongo plankton nets towed behind a boat. Environmental data were simultaneously collected using and acoustic Doppler current profiler (ADCP) and conductivity, temperature, depth (CTD) profiler. Larval fish abundance generally decreased with increasing distance from the shore, however, this varied in space and time, with some larval species recorded in high abundances offshore. Close inshore the larvae of coastal fish species producing benthic eggs (CBE) including the Blenniidae and Gobiesocidae mostly dominated, while offshore the larvae of coastal fish species producing pelagic eggs (CPE) i.e. Sparidae and Cynoglossidae, as well as pelagic fish species producing pelagic eggs (PPE) i.e. Clupeidae and Engraulidae mostly dominated. Vertical distribution of larvae differed according to taxon, with the Callionymidae (CPE), Cynoglossidae and Gobiesocidae occurring at high densities at the bottom of the water column, while the Blenniidae dominated near the surface. Fluorescence, temperature and salinity varied with depth (surface/bottom), being particularly high at the surface; currents moved faster at the surface than the bottom of the water column. Increased abundances of larval fishes were evident after upwelling events (associated with easterly winds) in the Bay, while during downwelling (associated with westerly winds), low densities were generally recorded, except for the sites situated near headlands/capes where there were higher densities of fish larvae during downwelling events. Overall, the results of this study suggest that spawning mode of the adults, oceanography and environmental conditions coupled with what is known of the behaviour of fish larvae, were important in shaping the larval fish community of the Algoa Bay region. These results highlight the importance of incorporating multiple biological (developmental stage, reproductive mode, species) and physical (currents, fluorescence, wind-driven up/down-welling) factors when addressing the mechanims of transport of larval fish in the coastal nearshore. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
Kwelo lizwe leentsomi : iintsomi zesiXhosa
- Authors: Sigcau, Bulelwa Monica
- Date: 2021-04
- Subjects: Creative writing (Higher education) -- South Africa , Xhosa fiction -- 21st century , Diaries -- Authorship , Short stories, Xhosa -- 21st century , African fiction -- History and criticism , English fiction -- History and criticism
- Language: Xhosa
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/178270 , vital:42926
- Description: Ukuphosa kuvimba wolwazi ngeentsomi zesiXhosa, le thisisi iqulathe iintsomi-mabali eziqanjwe zabaliswa kusetyenziswa ulwimi, umxholo nemixholo engenelelayo engeziganeko zemihla ngemihla, abalinganiswa, isakhiwo sentsomi nesimo sentlalo zala maxesha siphila kuwo. Ezi ntsomi zixhaswa kakhulu yimifanekiso ephilayo, ukusetyenziswa kwemigca emifutshane ezoba isimo sentlalo nevakala ingathi yimibongo ngenxa yokuqupha kwayo. Umsebenzi kaR.F. Mcimeli, kwincwadi ethi, Ingqaka kaMaqhudeni iqulethe iintsomi ezisondeleyo kwezi ziqanjwe kulo msebenzi, ngakumbi iintsomi ezizezi, uNomvula noNomvulazana, uDumisani nesigebenga esingabonwayo, uNomaciko noCikokazi, nezinye. Umsebenzi kaNongenile Masithathu Zenani (2006) oqokelelwe nguHarold Scheub kwincwadi ethi South African voices: A long time passed ube negaleloo elikhulu ukubonisa indima esele idlaliwe kwiintsomi zesiXhosa. UKholeka Sigenu (2002) kwincwandi ethi Ezakowethu naye ube nefuthe kwindlela ezi ntsomi eziqanjwe ngayo nokuqinisekisa ukuba ngenene zongeza ulwazi olutsha. Ezi ntsomi-mabali zibhentsise okulungileyo nokuhenxayo ngaphandle kokushumayela nokuveza abalinganiswa njengeengilosi. Ndiluthande kakhulu nohlobo lukaAmos Tutuola lokubhala, ndizame ukusondeza uhlobo lwam lokubhala kolu hlobo lukaAmos Tutuola. Ndilandele ifuthe lohlobo lokubhala olubizwa ngeflash fiction. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Sigcau, Bulelwa Monica
- Date: 2021-04
- Subjects: Creative writing (Higher education) -- South Africa , Xhosa fiction -- 21st century , Diaries -- Authorship , Short stories, Xhosa -- 21st century , African fiction -- History and criticism , English fiction -- History and criticism
- Language: Xhosa
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/178270 , vital:42926
- Description: Ukuphosa kuvimba wolwazi ngeentsomi zesiXhosa, le thisisi iqulathe iintsomi-mabali eziqanjwe zabaliswa kusetyenziswa ulwimi, umxholo nemixholo engenelelayo engeziganeko zemihla ngemihla, abalinganiswa, isakhiwo sentsomi nesimo sentlalo zala maxesha siphila kuwo. Ezi ntsomi zixhaswa kakhulu yimifanekiso ephilayo, ukusetyenziswa kwemigca emifutshane ezoba isimo sentlalo nevakala ingathi yimibongo ngenxa yokuqupha kwayo. Umsebenzi kaR.F. Mcimeli, kwincwadi ethi, Ingqaka kaMaqhudeni iqulethe iintsomi ezisondeleyo kwezi ziqanjwe kulo msebenzi, ngakumbi iintsomi ezizezi, uNomvula noNomvulazana, uDumisani nesigebenga esingabonwayo, uNomaciko noCikokazi, nezinye. Umsebenzi kaNongenile Masithathu Zenani (2006) oqokelelwe nguHarold Scheub kwincwadi ethi South African voices: A long time passed ube negaleloo elikhulu ukubonisa indima esele idlaliwe kwiintsomi zesiXhosa. UKholeka Sigenu (2002) kwincwandi ethi Ezakowethu naye ube nefuthe kwindlela ezi ntsomi eziqanjwe ngayo nokuqinisekisa ukuba ngenene zongeza ulwazi olutsha. Ezi ntsomi-mabali zibhentsise okulungileyo nokuhenxayo ngaphandle kokushumayela nokuveza abalinganiswa njengeengilosi. Ndiluthande kakhulu nohlobo lukaAmos Tutuola lokubhala, ndizame ukusondeza uhlobo lwam lokubhala kolu hlobo lukaAmos Tutuola. Ndilandele ifuthe lohlobo lokubhala olubizwa ngeflash fiction. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-04
Investigating the relationship between Heat Shock Proteins and HIV Transactivator of Transcription
- Authors: Flax, Lili Marie
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163307 , vital:41027
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Flax, Lili Marie
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163307 , vital:41027
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Date Issued: 2020
Investigating the factors that influence use of ICTs for citizen engagement in Malawi
- Authors: Sibande, Rachel Chavula
- Date: 2021-04
- Subjects: Information technology -- Malawi , Political participation -- Malawi , Mobile apps -- Malawi , UTAUT , Mzinda
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177019 , vital:42782 , 10.21504/10962/177019
- Description: Literature has suggested that Malawians are keen to participate. Malawian’s willingness to participate is evident as the country has recorded high voter turnouts during the elections in recent decades. However, literature also suggests that there is minimal citizen engagement in between elections. Elsewhere, Information and Communication Technologies (ICTs) have been used to enhance citizen engagement, but ICT led citizen engagement is still an emerging field and yet to be explored as an area of research particularly in Malawi. We thus sought to explore if the use of ICTs could improve citizen engagement with councils, councilors, and utility companies that provide water and electricity in Malawi. We developed and deployed an ICT platform called Mzinda which means My location in Malawi’s populous Chichewa language. The platform provided various channels for citizens and duty bearers to engage via SMS, USSD, web and a mobile application. We sought to understand the factors that influence citizen’s behavior intention to use an ICT platform to engage. We applied the modified UTAUT model by including Attitude and Self Efficacy social constructs that have among others been cited as limitations of the UTAUT model. We conducted factor loadings of six social constructs of the modified UTAUT model to validate content and reexamine the model in the context of citizen engagement using ICTs in Malawi. We found that, Attitude and Self Efficacy were not significant determinants of the Behaviour Intention for citizens to use the ICT platform. However, 75% of the Behaviour Intention was influenced by Perfomance Expectancy and Effort Expectancy as moderated by age and gender. Empirical evidence showed that responsiveness and actionability of councils and councillors had improved. We also learned that citizens believed that service delivery had improved and that they had more influence over councils, councillors, and the utility companies because of using the ICT platform. We conclude by noting that improvements in service delivery; enhanced responsiveness and actionability of councils, councillors and the utility companies were not necessarily as a result of the ICT platform alone; but a combination of ICTs and non-technology mechanisms of engaging the stakeholders through community campaigns, radio programs, print media engagement, community meetings and debates among others. It is evident that ICTs are not the panacea of all citizen engagement problems. This research can be useful to researchers and practitioners in the technology and citizen engagement domains. , Thesis (MSc) -- Faculty of Science, Department of Computer Science, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Sibande, Rachel Chavula
- Date: 2021-04
- Subjects: Information technology -- Malawi , Political participation -- Malawi , Mobile apps -- Malawi , UTAUT , Mzinda
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177019 , vital:42782 , 10.21504/10962/177019
- Description: Literature has suggested that Malawians are keen to participate. Malawian’s willingness to participate is evident as the country has recorded high voter turnouts during the elections in recent decades. However, literature also suggests that there is minimal citizen engagement in between elections. Elsewhere, Information and Communication Technologies (ICTs) have been used to enhance citizen engagement, but ICT led citizen engagement is still an emerging field and yet to be explored as an area of research particularly in Malawi. We thus sought to explore if the use of ICTs could improve citizen engagement with councils, councilors, and utility companies that provide water and electricity in Malawi. We developed and deployed an ICT platform called Mzinda which means My location in Malawi’s populous Chichewa language. The platform provided various channels for citizens and duty bearers to engage via SMS, USSD, web and a mobile application. We sought to understand the factors that influence citizen’s behavior intention to use an ICT platform to engage. We applied the modified UTAUT model by including Attitude and Self Efficacy social constructs that have among others been cited as limitations of the UTAUT model. We conducted factor loadings of six social constructs of the modified UTAUT model to validate content and reexamine the model in the context of citizen engagement using ICTs in Malawi. We found that, Attitude and Self Efficacy were not significant determinants of the Behaviour Intention for citizens to use the ICT platform. However, 75% of the Behaviour Intention was influenced by Perfomance Expectancy and Effort Expectancy as moderated by age and gender. Empirical evidence showed that responsiveness and actionability of councils and councillors had improved. We also learned that citizens believed that service delivery had improved and that they had more influence over councils, councillors, and the utility companies because of using the ICT platform. We conclude by noting that improvements in service delivery; enhanced responsiveness and actionability of councils, councillors and the utility companies were not necessarily as a result of the ICT platform alone; but a combination of ICTs and non-technology mechanisms of engaging the stakeholders through community campaigns, radio programs, print media engagement, community meetings and debates among others. It is evident that ICTs are not the panacea of all citizen engagement problems. This research can be useful to researchers and practitioners in the technology and citizen engagement domains. , Thesis (MSc) -- Faculty of Science, Department of Computer Science, 2021
- Full Text:
- Date Issued: 2021-04
Investigating cell culture models for improved understanding of adipose tissue and co-morbidities in vitro
- Authors: Stoffels, Mihlali
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164674 , vital:41154
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020
- Full Text:
- Date Issued: 2020
- Authors: Stoffels, Mihlali
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164674 , vital:41154
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020
- Full Text:
- Date Issued: 2020
Inhibitor search and variant analysis of Acetylcholinesterase
- Authors: Ras, Harnaud
- Date: 2021-04
- Subjects: Acetylcholinesterase , Alzheimer's disease , Acetylcholinesterase -- Inhibitors , Alzheimer's disease -- Chemotherapy , Cerebrovascular disease -- Treatment , Molecular mechanics Poisson–Boltzmann surface area (MM-PBSA)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178191 , vital:42919
- Description: Acetylcholinesterase (AChE) inhibition is used to treat Alzheimer's disease by increasing the availability of acetylcholine to carry nerve signals in the brain. The response to this treatment varies widely, which may be due to altered affnity to the current drugs caused by genetic variation. Various negative side-effects limit their use. As this is one of the only available therapeutic drug targets to treat Alzheimer's disease, decreasing the negative effects is of great importance. AChE is involved in biological processes that occur after acute ischemic stroke. Stroke is the third leading cause of death worldwide, and 87% of all stroke cases belong to ischemic stroke. AchEI (cholinesterase inhibitors) have been suggested to have properties that lower the risk of stroke. AChE is one of 15 verified drug targets under study for treatment of stroke. In addition to Alzheimer's disease and stroke, Lewy body disease (LBD) may be treated using cholinesterase inhibitors. The goals of this study are to find inhibitors that can potentially be used to treat Alzheimer's disease and/or stroke and to investigate variants which may affect protein dynamics and function. Two variants were analyzed, P247L and T229S. Molecular simulation of the P247L variant resulted in a disruption in protein dynamics in comparison to the wildtype. A total of 5728 molecules were screened and 10 nanosecond simulations were used to narrow down the set of compounds. The four best performing molecules were simulated for 10 nanoseconds. MM-PBSA was performed to identify molecules with high binding free energies. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Ras, Harnaud
- Date: 2021-04
- Subjects: Acetylcholinesterase , Alzheimer's disease , Acetylcholinesterase -- Inhibitors , Alzheimer's disease -- Chemotherapy , Cerebrovascular disease -- Treatment , Molecular mechanics Poisson–Boltzmann surface area (MM-PBSA)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178191 , vital:42919
- Description: Acetylcholinesterase (AChE) inhibition is used to treat Alzheimer's disease by increasing the availability of acetylcholine to carry nerve signals in the brain. The response to this treatment varies widely, which may be due to altered affnity to the current drugs caused by genetic variation. Various negative side-effects limit their use. As this is one of the only available therapeutic drug targets to treat Alzheimer's disease, decreasing the negative effects is of great importance. AChE is involved in biological processes that occur after acute ischemic stroke. Stroke is the third leading cause of death worldwide, and 87% of all stroke cases belong to ischemic stroke. AchEI (cholinesterase inhibitors) have been suggested to have properties that lower the risk of stroke. AChE is one of 15 verified drug targets under study for treatment of stroke. In addition to Alzheimer's disease and stroke, Lewy body disease (LBD) may be treated using cholinesterase inhibitors. The goals of this study are to find inhibitors that can potentially be used to treat Alzheimer's disease and/or stroke and to investigate variants which may affect protein dynamics and function. Two variants were analyzed, P247L and T229S. Molecular simulation of the P247L variant resulted in a disruption in protein dynamics in comparison to the wildtype. A total of 5728 molecules were screened and 10 nanosecond simulations were used to narrow down the set of compounds. The four best performing molecules were simulated for 10 nanoseconds. MM-PBSA was performed to identify molecules with high binding free energies. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
Indigenous knowledge of ecosystem services in rural communities of the Eastern Cape, South Africa
- Authors: Murata, Chenai
- Date: 2021-04
- Subjects: Ethnoscience -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Nature -- Effect of human beings on -- South Africa -- Eastern Cape , Human ecology -- South Africa -- Eastern Cape , Human beings -- Effect of environment on -- South Africa -- Eastern Cape , South Africa -- Eastern Cape -- Rural conditions
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177929 , vital:42891 , 10.21504/10962/177929
- Description: This thesis is on indigenous knowledge of ecosystem services. The ecosystem service framework and its associated concepts are fairly young, having been introduced in the ecological discipline in the 1980s. The ecosystem service framework posits that the wellbeing of humans and their communities is dependent on services supplied by ecosystems. It emphasises that for the ecosystems to be able to supply the services, they need to be in a well-functioning state. This idea of well-functioning is predicated on the argument that the ecosystem service framework enjoins resource users to exercise responsible stewardship to prevent degradation and overharvesting. Moreover, the concept of dependence suggests that ecosystem services are of value to humans. The dominant means of measuring the value of ecosystem services has been the economic valuation method in which the contribution that each service makes to human wellbeing is quantified into monetary units. The framework disaggregates the services into four groups, namely provisioning, cultural, supporting and regulatory and seeks to all the pillars of human wellbeing including health, subsistence and spirituality into each of these groups. In doing all this, the framework significantly reconfigures the way we look at and present human-nature relations. This change has the potential to influence significant shifts in how ecological research and intervention programmes are conducted in the foreseeable future. However, the reality that the ecosystem service framework was formulated within, and is informed by the scientific epistemology begs the question: what do traditional rural communities who depend mainly on indigenous knowledge systems (IKS) for shaping and interoperating their relations with nature know of the ecosystem service concept? Rural communities are the ones who interact directly with nature on a day-to-day basis. This makes them a very critical component in the ecosystem service framework. Although South Africa has had studies in the ecosystem service theme, little has been done to attempt to investigate and document indigenous knowledge of ecosystem services that rural communities possess. By focusing only on scientific knowledge of ecosystem services, the South African literature does not do justice to the plural epistemologies of the ecosystem service users in the country. More importantly, the continued dearth of public information on indigenous knowledge of ecosystem services can potentially obstruct implementation of locally sensitive intervention programmes because nothing is known about how the local communities conceptualise the ecosystem service framework. All this presents a crucial gap in the South African research; one that unless effort is made to contribute towards filling it, our knowledge of how communities experience the ecosystem service framework in South Africa will remain skewed. This study set out to investigate and document indigenous knowledge of ecosystem services in order to contribute towards filling this gap. Indigenous knowledge system is an umbrella epistemic system that includes lay ecological knowledge (LEK), traditional ecological knowledge (TEK) and many other related organized systems of knowing. Although the thesis has a chapter on LEK, its primary focus was TEK because the thesis was interested in unravelling how aspects of tradition including taboos, customs, traditional rules and belief in ancestral forces influence local communities’ knowledge of some key aspects of the ecosystem service framework including knowledge of various ecosystem services, valuation of ecosystem services, management of ecosystem services and perceptions of the management practices. The decision to focus on TEK was based on the reasoning that rural communities of the Eastern Cape boast a strong reputation of being traditional, recognizing ancestral spirits, legends and taboos as critical tools of knowledge generation and transmission. Using both mixed methods in some chapters and the qualitative approach alone in others, the study collected data in five villages of Mgwalana, Mahlungulu, Colana, Gogela and Nozitshena located in the north eastern part of Eastern Cape Province of South Africa, a region formerly called Transkei. The data were collected not on ecosystem services; but on the local people’s knowledge of ecosystem services. Although literature was consulted, the study regarded respondents as the primary source of data, hence the findings and conclusions presented in this thesis are about what local people know about ecosystem services. The study uses critical realist theoretical lenses to interpret respondents’ reports. The lenses included the principle of the separation between ontology and epistemology, the iceberg metaphor of ontology, epistemological pluralism and the hermeneutic dimension. These lenses were used to make sense of both the knowledge system of local people and the things about which their knowledge was. As part of discussing the local people’s knowledge, the study sometimes refers to science. This is not because I expected them to demonstrate knowledge similar to science. Instead, it was a critical realist dialectical way of explaining what something is by demonstrating what it is not. The study made a couple of key findings that can potentially enhance the growth of the South African ecosystem service discipline. First, respondents demonstrated knowledge of ecosystem services by mentioning a range of them such as drinking water, medicinal plants, cultural plants and fuelwood and how they affect the wellbeing of humans. However, what they did not have good knowledge of is that nature services can be classified into the four groups of supporting, regulatory, cultural and provisioning. Among the four ecosystem services groups, respondents could identify two only; provisional and cultural. Second, local communities depend heavily on ecosystem services for their well-being. The services include fuelwood, construction timber, medicinal plants, wild fruits, wild fish, cultural services and thatch grass. Although they appreciate that ecosystem services have value to their wellbeing, local people found it difficult to represent the value in monetary units. The conditions that make it difficult for local people to perceive ecosystem services as commodities include the absence of well-defined property system, lack of a quantitative consumer tradition and absence of an economic conception of nature. Third, local people understand the need to keep ecosystems in a well-functioning state hence they implement several traditional practices to manage ecosystem services. These practices include taboos, designating certain resources as sacred, legends, customary law, as well as some secular practices including gelesha and stone terracing. However, it is not easy to understand how traditional management practices work because they are not empirically observable. Fourth, local people possess knowledge of the reality that if not well managed, ecosystems can undergo degradation and hence fail to supply the services needed for human wellbeing. However, they explain the causes of degradation in terms of changes observable at the empirical level and the invisible causal power of supernatural forces. The inclusion of natural forces in degradation explanations marks a departure from the scientific explanations that revolve around biophysical processes. Fifth, the use of traditional management practices such as taboos to management ecosystems is under threat at the local communities. The threat can be attributed to three groups of causes, namely changes in worldviews due to adoption of formal education and Christianity, institutional disharmony playing out between the state and local traditional leadership, and lifestyle changes. These challenges constrain the opportunity for local people to apply traditional management practices to prevent the degradation of ecosystems. The net implication of this is that it renders it difficult for researchers and policy makers to assess the effectiveness of traditional management practices because they are not being implemented in full. In light of all these findings, the thesis concludes that TEK is underlabouring for the ecosystem service framework in the sense that it is used by local communities to generate knowledge of ecological concepts and phenomena. This means that TEK does not exist for the sake of its own self. Drawing from this finding, the study proposes a framework of analysing TEK as an underlabourer for social-ecological triggers or issues. Nonetheless, there are few factors that can be sources of limitation to the study. These include the reality that it was difficult to access pure traditional knowledge because over the years the local communities have received many state-sponsored ecological intervention programmes and a possible personal bias given the reality that I grew up in a traditional household and my father was a key holder or TEK. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2021 , Thesis chapter to be published in 'Green and Low-Carbon Economy'. Journal available: https://ojs.bonviewpress.com/index.php/GLCE/index
- Full Text:
- Date Issued: 2021-04
- Authors: Murata, Chenai
- Date: 2021-04
- Subjects: Ethnoscience -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Nature -- Effect of human beings on -- South Africa -- Eastern Cape , Human ecology -- South Africa -- Eastern Cape , Human beings -- Effect of environment on -- South Africa -- Eastern Cape , South Africa -- Eastern Cape -- Rural conditions
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177929 , vital:42891 , 10.21504/10962/177929
- Description: This thesis is on indigenous knowledge of ecosystem services. The ecosystem service framework and its associated concepts are fairly young, having been introduced in the ecological discipline in the 1980s. The ecosystem service framework posits that the wellbeing of humans and their communities is dependent on services supplied by ecosystems. It emphasises that for the ecosystems to be able to supply the services, they need to be in a well-functioning state. This idea of well-functioning is predicated on the argument that the ecosystem service framework enjoins resource users to exercise responsible stewardship to prevent degradation and overharvesting. Moreover, the concept of dependence suggests that ecosystem services are of value to humans. The dominant means of measuring the value of ecosystem services has been the economic valuation method in which the contribution that each service makes to human wellbeing is quantified into monetary units. The framework disaggregates the services into four groups, namely provisioning, cultural, supporting and regulatory and seeks to all the pillars of human wellbeing including health, subsistence and spirituality into each of these groups. In doing all this, the framework significantly reconfigures the way we look at and present human-nature relations. This change has the potential to influence significant shifts in how ecological research and intervention programmes are conducted in the foreseeable future. However, the reality that the ecosystem service framework was formulated within, and is informed by the scientific epistemology begs the question: what do traditional rural communities who depend mainly on indigenous knowledge systems (IKS) for shaping and interoperating their relations with nature know of the ecosystem service concept? Rural communities are the ones who interact directly with nature on a day-to-day basis. This makes them a very critical component in the ecosystem service framework. Although South Africa has had studies in the ecosystem service theme, little has been done to attempt to investigate and document indigenous knowledge of ecosystem services that rural communities possess. By focusing only on scientific knowledge of ecosystem services, the South African literature does not do justice to the plural epistemologies of the ecosystem service users in the country. More importantly, the continued dearth of public information on indigenous knowledge of ecosystem services can potentially obstruct implementation of locally sensitive intervention programmes because nothing is known about how the local communities conceptualise the ecosystem service framework. All this presents a crucial gap in the South African research; one that unless effort is made to contribute towards filling it, our knowledge of how communities experience the ecosystem service framework in South Africa will remain skewed. This study set out to investigate and document indigenous knowledge of ecosystem services in order to contribute towards filling this gap. Indigenous knowledge system is an umbrella epistemic system that includes lay ecological knowledge (LEK), traditional ecological knowledge (TEK) and many other related organized systems of knowing. Although the thesis has a chapter on LEK, its primary focus was TEK because the thesis was interested in unravelling how aspects of tradition including taboos, customs, traditional rules and belief in ancestral forces influence local communities’ knowledge of some key aspects of the ecosystem service framework including knowledge of various ecosystem services, valuation of ecosystem services, management of ecosystem services and perceptions of the management practices. The decision to focus on TEK was based on the reasoning that rural communities of the Eastern Cape boast a strong reputation of being traditional, recognizing ancestral spirits, legends and taboos as critical tools of knowledge generation and transmission. Using both mixed methods in some chapters and the qualitative approach alone in others, the study collected data in five villages of Mgwalana, Mahlungulu, Colana, Gogela and Nozitshena located in the north eastern part of Eastern Cape Province of South Africa, a region formerly called Transkei. The data were collected not on ecosystem services; but on the local people’s knowledge of ecosystem services. Although literature was consulted, the study regarded respondents as the primary source of data, hence the findings and conclusions presented in this thesis are about what local people know about ecosystem services. The study uses critical realist theoretical lenses to interpret respondents’ reports. The lenses included the principle of the separation between ontology and epistemology, the iceberg metaphor of ontology, epistemological pluralism and the hermeneutic dimension. These lenses were used to make sense of both the knowledge system of local people and the things about which their knowledge was. As part of discussing the local people’s knowledge, the study sometimes refers to science. This is not because I expected them to demonstrate knowledge similar to science. Instead, it was a critical realist dialectical way of explaining what something is by demonstrating what it is not. The study made a couple of key findings that can potentially enhance the growth of the South African ecosystem service discipline. First, respondents demonstrated knowledge of ecosystem services by mentioning a range of them such as drinking water, medicinal plants, cultural plants and fuelwood and how they affect the wellbeing of humans. However, what they did not have good knowledge of is that nature services can be classified into the four groups of supporting, regulatory, cultural and provisioning. Among the four ecosystem services groups, respondents could identify two only; provisional and cultural. Second, local communities depend heavily on ecosystem services for their well-being. The services include fuelwood, construction timber, medicinal plants, wild fruits, wild fish, cultural services and thatch grass. Although they appreciate that ecosystem services have value to their wellbeing, local people found it difficult to represent the value in monetary units. The conditions that make it difficult for local people to perceive ecosystem services as commodities include the absence of well-defined property system, lack of a quantitative consumer tradition and absence of an economic conception of nature. Third, local people understand the need to keep ecosystems in a well-functioning state hence they implement several traditional practices to manage ecosystem services. These practices include taboos, designating certain resources as sacred, legends, customary law, as well as some secular practices including gelesha and stone terracing. However, it is not easy to understand how traditional management practices work because they are not empirically observable. Fourth, local people possess knowledge of the reality that if not well managed, ecosystems can undergo degradation and hence fail to supply the services needed for human wellbeing. However, they explain the causes of degradation in terms of changes observable at the empirical level and the invisible causal power of supernatural forces. The inclusion of natural forces in degradation explanations marks a departure from the scientific explanations that revolve around biophysical processes. Fifth, the use of traditional management practices such as taboos to management ecosystems is under threat at the local communities. The threat can be attributed to three groups of causes, namely changes in worldviews due to adoption of formal education and Christianity, institutional disharmony playing out between the state and local traditional leadership, and lifestyle changes. These challenges constrain the opportunity for local people to apply traditional management practices to prevent the degradation of ecosystems. The net implication of this is that it renders it difficult for researchers and policy makers to assess the effectiveness of traditional management practices because they are not being implemented in full. In light of all these findings, the thesis concludes that TEK is underlabouring for the ecosystem service framework in the sense that it is used by local communities to generate knowledge of ecological concepts and phenomena. This means that TEK does not exist for the sake of its own self. Drawing from this finding, the study proposes a framework of analysing TEK as an underlabourer for social-ecological triggers or issues. Nonetheless, there are few factors that can be sources of limitation to the study. These include the reality that it was difficult to access pure traditional knowledge because over the years the local communities have received many state-sponsored ecological intervention programmes and a possible personal bias given the reality that I grew up in a traditional household and my father was a key holder or TEK. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2021 , Thesis chapter to be published in 'Green and Low-Carbon Economy'. Journal available: https://ojs.bonviewpress.com/index.php/GLCE/index
- Full Text:
- Date Issued: 2021-04
In silico identification of selective novel hits against the active site of wild type mycobacterium tuberculosis pyrazinamidase and its mutants
- Authors: Gowo, Prudence
- Date: 2021-04
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Multidrug resistance , Antitubercular agents , Molecular dynamics , Hydrogen bonding , Ligand binding (Biochemistry) , Dynamic Residue Network
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178007 , vital:42898
- Description: The World Health Organization declared Tuberculosis a global health emergency and has set a goal to eradicate it by 2035. However, effective treatment and control of the disease is being hindered by the emerging Multi-Drug Resistant and Extensively Drug Resistant strains on the most effective first line prodrug, Pyrazinamide (PZA). Studies have shown that the main cause of PZA resistance is due to mutations in the pncA gene that codes for the target protein Pyrazinamidase (PZase). Therefore, this study aimed to identify novel drug compounds that bind to the active site of wild type PZase and study the dynamics of these potential anti-TB drugs in the mutant systems of PZase. This approach will aid in identifying drugs that may be repurposed for TB therapy and/or designed to counteract PZA resistance. This was achieved by screening 2089 DrugBank compounds against the whole wild type (WT) PZase protein in molecular docking using AutoDOCK4.2. Compound screening based on docking binding energy, hydrogen bonds, molecular weight and active site proximity identified 47 compounds meeting all the set selection criteria. The stability of these compounds were analysed in Molecular Dynamic (MD) simulations and were further studied in PZase mutant systems of A3P, A134V, A146V, D8G, D49A, D49G, D63G, H51P, H137R, L85R, L116R, Q10P, R140S, T61P, V139M and Y103S. Generally, mutant-ligand systems displayed little deviation from the WT systems. The compound systems remained compact, with less fluctuations and more hydrogen bond interactions throughout the simulation (DB00255, DB00655, DB00672, DB00782, DB00977, DB01196, DB04573, DB06414, DB08981, DB11181, DB11760, DB13867, DB13952). From this research study, potential drugs that may be repurposed for TB therapy were identified. Majority of these drugs are currently used in the treatment of hypertension, menopause disorders and inflammation. To further understand the mutant-ligand dynamic systems, calculations such as Dynamic Residue Network (DRN) may be done. Also, the bioactivity of these drugs on Mycobacterium tuberculosis may be studied in wet laboratory, to understand their clinical impart in vivo experiments. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Gowo, Prudence
- Date: 2021-04
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Multidrug resistance , Antitubercular agents , Molecular dynamics , Hydrogen bonding , Ligand binding (Biochemistry) , Dynamic Residue Network
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178007 , vital:42898
- Description: The World Health Organization declared Tuberculosis a global health emergency and has set a goal to eradicate it by 2035. However, effective treatment and control of the disease is being hindered by the emerging Multi-Drug Resistant and Extensively Drug Resistant strains on the most effective first line prodrug, Pyrazinamide (PZA). Studies have shown that the main cause of PZA resistance is due to mutations in the pncA gene that codes for the target protein Pyrazinamidase (PZase). Therefore, this study aimed to identify novel drug compounds that bind to the active site of wild type PZase and study the dynamics of these potential anti-TB drugs in the mutant systems of PZase. This approach will aid in identifying drugs that may be repurposed for TB therapy and/or designed to counteract PZA resistance. This was achieved by screening 2089 DrugBank compounds against the whole wild type (WT) PZase protein in molecular docking using AutoDOCK4.2. Compound screening based on docking binding energy, hydrogen bonds, molecular weight and active site proximity identified 47 compounds meeting all the set selection criteria. The stability of these compounds were analysed in Molecular Dynamic (MD) simulations and were further studied in PZase mutant systems of A3P, A134V, A146V, D8G, D49A, D49G, D63G, H51P, H137R, L85R, L116R, Q10P, R140S, T61P, V139M and Y103S. Generally, mutant-ligand systems displayed little deviation from the WT systems. The compound systems remained compact, with less fluctuations and more hydrogen bond interactions throughout the simulation (DB00255, DB00655, DB00672, DB00782, DB00977, DB01196, DB04573, DB06414, DB08981, DB11181, DB11760, DB13867, DB13952). From this research study, potential drugs that may be repurposed for TB therapy were identified. Majority of these drugs are currently used in the treatment of hypertension, menopause disorders and inflammation. To further understand the mutant-ligand dynamic systems, calculations such as Dynamic Residue Network (DRN) may be done. Also, the bioactivity of these drugs on Mycobacterium tuberculosis may be studied in wet laboratory, to understand their clinical impart in vivo experiments. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04