The impact of corruption on stock market performance : evidence from BRICS
- Authors: Kapase, Siphe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462724 , vital:76329
- Description: This thesis examines the impact of corruption perception on stock market performance across BRICS nations from 2010 to 2022 using a primarily quantitative approach. Grounded in theoretical frameworks such as Corruption as Grease, Corruption as Sand, and New Institutional Economics, the study employs the Panel Autoregressive Distributed Lag (ARDL) model. It explores how corruption perceptions influence stock market capitalization (MCAP) over various time horizons. It utilizes empirical data and advanced techniques like unit root testing and cointegration tests to provide insights into short-term fluctuations and long-term trends in financial markets. The findings reveal significant long-term negative effects of the corruption perception index (CPI) on MCAP. Higher levels of perceived corruption correlate with lower stock market capitalization over extended periods, underscoring the persistent impact of institutional weaknesses on market stability. Short-term analyses show varying adjustment speeds towards equilibrium among BRICS nations, reflecting different economic contexts and policy responses to corruption. The findings suggest that investors should focus on markets with lower corruption perceptions for better stock market performance and advise policymakers to enhance transparency to build more resilient financial markets. Future research should continue to explore the impact of corruption on BRICS nations. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Kapase, Siphe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462724 , vital:76329
- Description: This thesis examines the impact of corruption perception on stock market performance across BRICS nations from 2010 to 2022 using a primarily quantitative approach. Grounded in theoretical frameworks such as Corruption as Grease, Corruption as Sand, and New Institutional Economics, the study employs the Panel Autoregressive Distributed Lag (ARDL) model. It explores how corruption perceptions influence stock market capitalization (MCAP) over various time horizons. It utilizes empirical data and advanced techniques like unit root testing and cointegration tests to provide insights into short-term fluctuations and long-term trends in financial markets. The findings reveal significant long-term negative effects of the corruption perception index (CPI) on MCAP. Higher levels of perceived corruption correlate with lower stock market capitalization over extended periods, underscoring the persistent impact of institutional weaknesses on market stability. Short-term analyses show varying adjustment speeds towards equilibrium among BRICS nations, reflecting different economic contexts and policy responses to corruption. The findings suggest that investors should focus on markets with lower corruption perceptions for better stock market performance and advise policymakers to enhance transparency to build more resilient financial markets. Future research should continue to explore the impact of corruption on BRICS nations. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
Neutral winds and tides over South Africa
- Authors: Ojo, Taiwo Theophilus
- Date: 2022-04-08
- Subjects: Atmospheric tides , Ionosondes , Fabry-Perot interferometers , Thermospheric winds , Servomechanisms , Climatology , Neutral winds , Horizontal Wind Model (HWM)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232459 , vital:49993 , DOI 10.21504/10962/232459
- Description: This thesis presents the first results of a climatology of nighttime thermospheric neutral winds between February 2018 and January 2019 measured by a Fabry-Perot interferometer (FPI) in Sutherland, South Africa (32.2°S, 20.48°E; geomagnetic latitude: 40.7°S). This FPI measures the nighttime oxygen airglow emission at 630.0 nm, which has a peak intensity at an altitude of roughly 250 km. The performance of the Horizontal Wind Model (HWM14) was evaluated by comparing results from HWM14 with the FPI measurements. The results showed that the model had a better agreement with the measurements for meridional component compared to the zonal component. In addition, the HWM14 zonal wind consistently peaked several hours (~3 h) prior to the measured wind, creating what looks like a phase shift compared to the measured wind. An investigation of this apparent phase shift revealed it to be a consequence of a difference in phase shift of the terdiunal tide. Since ionosondes are more prolific with wider temporal and spatial coverage than FPIs, nighttime meridional winds aligned to the magnetic meridian were inferred from the peak height (hmF2) of ionospheric data taken from South Africa ionosonde network using the servo model during February 2018-June 2019. These were compared with FPI measured meridional wind and benchmarked with HWM14 and Magnetic mEridional NeuTrAl Thermospheric (MENTAT) model. The amplitudes and trends of the calculated meridional winds across all four ionosonde stations agreed relatively well with the observed data, especially during the summer months. Furthermore, the results confirmed that the ionosonde station located closest to the FPI, i.e. Hermanus station, had better agreement with measurements compared to the stations located at further distances. The extraction and analysis of atmospheric tides, namely the diurnal, semidiurnal, terdiurnal and 6-hour components from the FPI as well as the long-term tidal winds variations from the thermospheric wind measurements were investigated. The results showed that the semidiurnal peak mostly had the highest peak across all the months, indicating that the semidiurnal tides dominate the dynamic structure of the upper mesosphere at midlatitudes, consistent with previous observation over midlatitudes. Futhermore, the signature of the diurnal tide in the meridional (zonal) wind was stronger in winter (summer) and weaker in summer (winter). Also, semidiurnal tide didn't show any trend with season, while the terdiurnal tide was dominant in summer (zonal) and winter (meridional). Lastly, the 6 hour tide was detected intermittently during the period of the study and had the weakest signature (i.e. lowest amplitudes). , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Ojo, Taiwo Theophilus
- Date: 2022-04-08
- Subjects: Atmospheric tides , Ionosondes , Fabry-Perot interferometers , Thermospheric winds , Servomechanisms , Climatology , Neutral winds , Horizontal Wind Model (HWM)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232459 , vital:49993 , DOI 10.21504/10962/232459
- Description: This thesis presents the first results of a climatology of nighttime thermospheric neutral winds between February 2018 and January 2019 measured by a Fabry-Perot interferometer (FPI) in Sutherland, South Africa (32.2°S, 20.48°E; geomagnetic latitude: 40.7°S). This FPI measures the nighttime oxygen airglow emission at 630.0 nm, which has a peak intensity at an altitude of roughly 250 km. The performance of the Horizontal Wind Model (HWM14) was evaluated by comparing results from HWM14 with the FPI measurements. The results showed that the model had a better agreement with the measurements for meridional component compared to the zonal component. In addition, the HWM14 zonal wind consistently peaked several hours (~3 h) prior to the measured wind, creating what looks like a phase shift compared to the measured wind. An investigation of this apparent phase shift revealed it to be a consequence of a difference in phase shift of the terdiunal tide. Since ionosondes are more prolific with wider temporal and spatial coverage than FPIs, nighttime meridional winds aligned to the magnetic meridian were inferred from the peak height (hmF2) of ionospheric data taken from South Africa ionosonde network using the servo model during February 2018-June 2019. These were compared with FPI measured meridional wind and benchmarked with HWM14 and Magnetic mEridional NeuTrAl Thermospheric (MENTAT) model. The amplitudes and trends of the calculated meridional winds across all four ionosonde stations agreed relatively well with the observed data, especially during the summer months. Furthermore, the results confirmed that the ionosonde station located closest to the FPI, i.e. Hermanus station, had better agreement with measurements compared to the stations located at further distances. The extraction and analysis of atmospheric tides, namely the diurnal, semidiurnal, terdiurnal and 6-hour components from the FPI as well as the long-term tidal winds variations from the thermospheric wind measurements were investigated. The results showed that the semidiurnal peak mostly had the highest peak across all the months, indicating that the semidiurnal tides dominate the dynamic structure of the upper mesosphere at midlatitudes, consistent with previous observation over midlatitudes. Futhermore, the signature of the diurnal tide in the meridional (zonal) wind was stronger in winter (summer) and weaker in summer (winter). Also, semidiurnal tide didn't show any trend with season, while the terdiurnal tide was dominant in summer (zonal) and winter (meridional). Lastly, the 6 hour tide was detected intermittently during the period of the study and had the weakest signature (i.e. lowest amplitudes). , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-04-08
Shifting the Narrative on Food Insecurity: An Investigation into the Potential Power of Social Media to Promote Sustainable Practices
- Authors: De Raedt, Amy
- Date: 2022-04
- Subjects: Food security--South Africa , Ecosocialism--South Africa , Economic development--Moral and ethical aspects
- Language: English
- Type: Master'stheses , text
- Identifier: http://hdl.handle.net/10948/55290 , vital:51448
- Description: Food insecurity is a prevailing problem and according to a report released in 2019 by the Food and Agriculture Organization (FAO), about 2 billion people in the world experience moderate or severe food insecurity (FAO, IFAD, UNICEF, WFP and WHO 2019: vii). Consequently, if we are to make a significant change in these statistics, the actions taken to “tackle these troubling trends will have to be bolder, not only in scale but also in terms of multisectoral collaboration” (2019: viii). It is against this backdrop that this study will explore the discursive landscape around four social media applications - OLIO, Too Good To Go (TGTG), KHULA and OneFarm Share - working to fight food waste, tackle food insecurity and reimagine the food system. This study is situated in the field of media studies and adopts a qualitative approach, with hermeneutics as the specific research strategy which “[seeks] understanding, rather than to offer explanation” (Kinsella 2006: n.p). This study maps the development of media effect theories over the years and explores where it is today, drawing on key thinkers in the space of new media including Lister, Manovich and Castells. This is followed by a discussion of food insecurity globally, and then locally within a South African context, as well as through the lens of ecosocialism drawing on voices such as Kovel and Löwy. This will lead to a content analysis of the four selected applications exploring the discursive landscape around each, and what similarities and disparities emerge. , Thesis (MA) -- Faculty of Humanities, Language, Media and Communications, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: De Raedt, Amy
- Date: 2022-04
- Subjects: Food security--South Africa , Ecosocialism--South Africa , Economic development--Moral and ethical aspects
- Language: English
- Type: Master'stheses , text
- Identifier: http://hdl.handle.net/10948/55290 , vital:51448
- Description: Food insecurity is a prevailing problem and according to a report released in 2019 by the Food and Agriculture Organization (FAO), about 2 billion people in the world experience moderate or severe food insecurity (FAO, IFAD, UNICEF, WFP and WHO 2019: vii). Consequently, if we are to make a significant change in these statistics, the actions taken to “tackle these troubling trends will have to be bolder, not only in scale but also in terms of multisectoral collaboration” (2019: viii). It is against this backdrop that this study will explore the discursive landscape around four social media applications - OLIO, Too Good To Go (TGTG), KHULA and OneFarm Share - working to fight food waste, tackle food insecurity and reimagine the food system. This study is situated in the field of media studies and adopts a qualitative approach, with hermeneutics as the specific research strategy which “[seeks] understanding, rather than to offer explanation” (Kinsella 2006: n.p). This study maps the development of media effect theories over the years and explores where it is today, drawing on key thinkers in the space of new media including Lister, Manovich and Castells. This is followed by a discussion of food insecurity globally, and then locally within a South African context, as well as through the lens of ecosocialism drawing on voices such as Kovel and Löwy. This will lead to a content analysis of the four selected applications exploring the discursive landscape around each, and what similarities and disparities emerge. , Thesis (MA) -- Faculty of Humanities, Language, Media and Communications, 2022
- Full Text:
- Date Issued: 2022-04
An evaluation of communication strategies for the eradication of female genital mutilation (FGM): a case study of West Pokot, Kenya
- Authors: Onyango, Quinter
- Date: 2021-09
- Subjects: Female circumcision , Communication
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21103 , vital:46986
- Description: Female Genital Mutilation (FGM) is still rampant in many Kenya communities, especially the Maa and the Pokot speaking people, despite communication strategies and programmes instituted to eradicate the cultural practice. Female Genital Mutilation is a procedure that intentionally alters or cause injury to the female genital organs for non-medical reasons. The gains of eliminating FGM resulted from robust communication strategies introduced by the United Nations and the Kenyan government to educate and raise consciousness regarding the dangers of FGM practice. However, despite widespread communication efforts worldwide, at least thirty-one countries are still practising FGM. West Pokot County in Kenya has an 86% rate as a county that still practices FGM. The statistics are an indication that communication alone cannot achieve the desired goal as long as the communities feel that these organizations and their communication expects are looking down upon their culture, beliefs and practices. As far as FGM is concerned, attitude change is vital in communities to understand the dangers. Members of communities are often left behind or not consulted when developing strategies for eradicating FGM. Emphasis should be drawn on the involvement and ownership of such development programmes. Lack of participation from the communities seems to be the key reason for the failure of the campaigns to encourage people into deserting FGM practices. Therefore, this study evaluated communication strategies and explanations of why there is still a high level of FGM practice regardless of the prevalent consciousness of the consequences of its continued practice in West Pokot County, Kenya. This study adopts a mixed methodology (qualitative and quantitative) research approach. Convenience and purposive non-probability sampling techniques were subsequently used to select samples for this study. In-depth interviews and focus group discussions were held with the different community members in West Pokot County. There were five focus groups with nine participants in each focus group, making 45 participants for the focus group discussions. The collected data were interpreted and analysed thematically. This research showed a remarkable disparity between the community members ranging from their opinion and perceptions on the best and effective modes of communication to eradicate female genital mutilation and an alternative rite of passage. Another critical finding of this study indicated that beads of bondage linked to the community sanctioned rite of passage are another traditional practice that is endangering the lives of the girl child in Lokornoi, West Pokot County. Hence, this study proposed using mass media (newspapers, radio, television) using their vernacular language, which they understand and other interpersonal communication strategies (elders, chiefs and religious leaders) to eradicate FGM. Also, communication groups can involve communities to encourage a sense of ownership, which was the biggest reason for the communities to resist leaving FGM practice. This research suggests a need to develop alternative ways of communicating the message and that interpersonal channels are necessary to eradicate FGM in Kenya. , Thesis (MSoc Sci) (Communication) -- University of Fort Hare, 2021
- Full Text:
- Date Issued: 2021-09
- Authors: Onyango, Quinter
- Date: 2021-09
- Subjects: Female circumcision , Communication
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21103 , vital:46986
- Description: Female Genital Mutilation (FGM) is still rampant in many Kenya communities, especially the Maa and the Pokot speaking people, despite communication strategies and programmes instituted to eradicate the cultural practice. Female Genital Mutilation is a procedure that intentionally alters or cause injury to the female genital organs for non-medical reasons. The gains of eliminating FGM resulted from robust communication strategies introduced by the United Nations and the Kenyan government to educate and raise consciousness regarding the dangers of FGM practice. However, despite widespread communication efforts worldwide, at least thirty-one countries are still practising FGM. West Pokot County in Kenya has an 86% rate as a county that still practices FGM. The statistics are an indication that communication alone cannot achieve the desired goal as long as the communities feel that these organizations and their communication expects are looking down upon their culture, beliefs and practices. As far as FGM is concerned, attitude change is vital in communities to understand the dangers. Members of communities are often left behind or not consulted when developing strategies for eradicating FGM. Emphasis should be drawn on the involvement and ownership of such development programmes. Lack of participation from the communities seems to be the key reason for the failure of the campaigns to encourage people into deserting FGM practices. Therefore, this study evaluated communication strategies and explanations of why there is still a high level of FGM practice regardless of the prevalent consciousness of the consequences of its continued practice in West Pokot County, Kenya. This study adopts a mixed methodology (qualitative and quantitative) research approach. Convenience and purposive non-probability sampling techniques were subsequently used to select samples for this study. In-depth interviews and focus group discussions were held with the different community members in West Pokot County. There were five focus groups with nine participants in each focus group, making 45 participants for the focus group discussions. The collected data were interpreted and analysed thematically. This research showed a remarkable disparity between the community members ranging from their opinion and perceptions on the best and effective modes of communication to eradicate female genital mutilation and an alternative rite of passage. Another critical finding of this study indicated that beads of bondage linked to the community sanctioned rite of passage are another traditional practice that is endangering the lives of the girl child in Lokornoi, West Pokot County. Hence, this study proposed using mass media (newspapers, radio, television) using their vernacular language, which they understand and other interpersonal communication strategies (elders, chiefs and religious leaders) to eradicate FGM. Also, communication groups can involve communities to encourage a sense of ownership, which was the biggest reason for the communities to resist leaving FGM practice. This research suggests a need to develop alternative ways of communicating the message and that interpersonal channels are necessary to eradicate FGM in Kenya. , Thesis (MSoc Sci) (Communication) -- University of Fort Hare, 2021
- Full Text:
- Date Issued: 2021-09
Baculovirus synergism for improved management of false codling moth Thaumatotibia leucotreta Meyr. (Lepidoptera: Tortricidae)
- Authors: Taylor, David Graham
- Date: 2021-04
- Subjects: Baculoviruses , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Biological control , Biological pest control agents , Citrus -- Diseases and pests , Codling moth , Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/176942 , vital:42774
- Description: Baculoviruses are an environmentally friendly and effective agent for managing lepidopteran pests. This includes the management of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a serious pest of citrus in Southern Africa and a major threat to the South African citrus export industry. For more than 15 years, CrleGV-SA- based biopesticides have been used as part of an integrated pest management strategy for the control of T. leucotreta in citrus orchards in South Africa, under the names Cryptogran™ and Cryptex®. While these biopesticides have been effective during this period, there are some areas in which baculovirus use could potentially be improved. Baculoviruses are notoriously slow to kill in comparison to chemical-based pesticides, and lately, pest resistance to baculoviruses has become a major concern with the development of resistance by Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) to its granulovirus occurring in the field in Europe. The consistent use of CrleGV-SA for more than 15 years in the field has raised concern that T. leucotreta could develop resistance to this virus, and has made it necessary to alter baculovirus-based management strategies to prevent this from occurring. A second baculovirus, Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV), has recently been isolated and was shown to be effective against T. leucotreta. However, the interactions between CrleGV-SA and CrpeNPV are not yet understood and so it is important to test these interactions before both viruses are applied on the same orchards. Not only is it important to know whether these viruses could negatively impact each other, but it is also important to test whether they could interact synergistically. A synergistic interaction could not only provide a potential tool for the management of resistance, but it could also be exploited to improve baculovirus-based management of T. leucotreta. In this study, a stock of CrleGV-SA was purified by glycerol gradient centrifugation from T. leucotreta cadavers, while a stock of CrpeNPV purified from Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae) cadavers was provided by River Bioscience (Pty) Ltd. These stocks were screened for purity by a multiplex polymerase chain reaction (mPCR) protocol designed to detect CrleGV-SA and CrpeNPV. The occlusion body (OB) density was then calculated using darkfield microscopy and a counting chamber. Both stocks were shown to be pure within the limits of the mPCR protocol, and the CrleGV-SA and CrpeNPV stocks were calculated to contain 3.08 × 1011 OBs/mL and 1.92 × 1011 OBs/mL respectively The first aspect of the interaction between CrleGV-SA and CrpeNPV that was investigated was the dose mortality, in terms of lethal concentration. This was calculated using 7-day surface-dose biological assays for each virus and a 1:1 mixture of OBs of the two against T. leucotreta neonates. The lethal concentrations of each treatment required to kill 50 % of larvae (LC50) and 90 % of larvae (LC90) for each treatment were then calculated and compared using a probit regression. The mixed infection performed significantly better than either virus by itself, while each virus by itself did not differ significantly from the other. The LC50 for CrleGV-SA, CrpeNPV and the mixed infection were 1.53 × 104 OBs/mL, 1.15 × 104 OBs/mL and 4.38 × 103 OBs/mL respectively. The LC90 of CrleGV-SA, CrpeNPV and the mixed infection were calculated to be 4.10 × 105 OBs/mL, 1.05 × 105 OBs/mL, and 4.09 × 104 OBs/mL respectively. The second aspect of the interaction between CrleGV-SA and CrpeNPV that was investigated was the speed of kill. A time-response biological assay protocol was created that allowed for effective observation of the larvae. This was then used to generate time-mortality data that were analysed by a logit regression function to calculate and compare the treatments at the time of 50 % larval mortality (LT50) and the time of 90 % mortality (LT90). Each virus by itself did not differ significantly from the other, while the mixed infection took significantly longer to kill 50 % and 90 % of the larvae, suggesting that there is competition for resources between viruses during the secondary, systemic phase of infection. The LT50 for CrleGV-SA, CrpeNPV and the mixed infection were 117.5 hours, 113.5 hours and 139.0 hours respectively. The LT90 for CrleGV-SA, CrpeNPV and the mixed infection were 153.2 hours, 159.3, and 193.4 hours respectively. Finally, the composition of OBs recovered from the cadavers produced by the time-response biological assays were investigated by mPCR. A method for extracting gDNA from OBs in neonate-sized T. leucotreta larvae is described. The presence of CrpeNPV along with CrleGV-SA was noted in 4 out of 9 larvae inoculated with only CrleGV-SA. The presence of CrleGV-SA as well as CrpeNPV was noted in all but one larva inoculated with only CrpeNPV, and both CrleGV-SA and CrpeNPV were noted in all but one larva inoculated with a 1:1 mixture of the two, with one larva only being positive for CrleGV-SA. This suggests either stock contamination or the presence of covert infections of CrleGV-SA and CrpeNPV in the T. leucotreta population used in this study. This is the second study to report an improved lethal concentration of a mixed infection of CrleGV-SA and CrpeNPV against T. leucotreta neonates, and the first study to report the slower speed of kill of a mixed infection of CrleGV-SA and CrpeNPV against T. leucotreta neonates. While the improved lethal concentration of the mixed infection is a promising step in the future improvement of baculovirus-based biopesticides, it is at the cost of a slower speed of kill. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Taylor, David Graham
- Date: 2021-04
- Subjects: Baculoviruses , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Biological control , Biological pest control agents , Citrus -- Diseases and pests , Codling moth , Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/176942 , vital:42774
- Description: Baculoviruses are an environmentally friendly and effective agent for managing lepidopteran pests. This includes the management of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a serious pest of citrus in Southern Africa and a major threat to the South African citrus export industry. For more than 15 years, CrleGV-SA- based biopesticides have been used as part of an integrated pest management strategy for the control of T. leucotreta in citrus orchards in South Africa, under the names Cryptogran™ and Cryptex®. While these biopesticides have been effective during this period, there are some areas in which baculovirus use could potentially be improved. Baculoviruses are notoriously slow to kill in comparison to chemical-based pesticides, and lately, pest resistance to baculoviruses has become a major concern with the development of resistance by Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) to its granulovirus occurring in the field in Europe. The consistent use of CrleGV-SA for more than 15 years in the field has raised concern that T. leucotreta could develop resistance to this virus, and has made it necessary to alter baculovirus-based management strategies to prevent this from occurring. A second baculovirus, Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV), has recently been isolated and was shown to be effective against T. leucotreta. However, the interactions between CrleGV-SA and CrpeNPV are not yet understood and so it is important to test these interactions before both viruses are applied on the same orchards. Not only is it important to know whether these viruses could negatively impact each other, but it is also important to test whether they could interact synergistically. A synergistic interaction could not only provide a potential tool for the management of resistance, but it could also be exploited to improve baculovirus-based management of T. leucotreta. In this study, a stock of CrleGV-SA was purified by glycerol gradient centrifugation from T. leucotreta cadavers, while a stock of CrpeNPV purified from Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae) cadavers was provided by River Bioscience (Pty) Ltd. These stocks were screened for purity by a multiplex polymerase chain reaction (mPCR) protocol designed to detect CrleGV-SA and CrpeNPV. The occlusion body (OB) density was then calculated using darkfield microscopy and a counting chamber. Both stocks were shown to be pure within the limits of the mPCR protocol, and the CrleGV-SA and CrpeNPV stocks were calculated to contain 3.08 × 1011 OBs/mL and 1.92 × 1011 OBs/mL respectively The first aspect of the interaction between CrleGV-SA and CrpeNPV that was investigated was the dose mortality, in terms of lethal concentration. This was calculated using 7-day surface-dose biological assays for each virus and a 1:1 mixture of OBs of the two against T. leucotreta neonates. The lethal concentrations of each treatment required to kill 50 % of larvae (LC50) and 90 % of larvae (LC90) for each treatment were then calculated and compared using a probit regression. The mixed infection performed significantly better than either virus by itself, while each virus by itself did not differ significantly from the other. The LC50 for CrleGV-SA, CrpeNPV and the mixed infection were 1.53 × 104 OBs/mL, 1.15 × 104 OBs/mL and 4.38 × 103 OBs/mL respectively. The LC90 of CrleGV-SA, CrpeNPV and the mixed infection were calculated to be 4.10 × 105 OBs/mL, 1.05 × 105 OBs/mL, and 4.09 × 104 OBs/mL respectively. The second aspect of the interaction between CrleGV-SA and CrpeNPV that was investigated was the speed of kill. A time-response biological assay protocol was created that allowed for effective observation of the larvae. This was then used to generate time-mortality data that were analysed by a logit regression function to calculate and compare the treatments at the time of 50 % larval mortality (LT50) and the time of 90 % mortality (LT90). Each virus by itself did not differ significantly from the other, while the mixed infection took significantly longer to kill 50 % and 90 % of the larvae, suggesting that there is competition for resources between viruses during the secondary, systemic phase of infection. The LT50 for CrleGV-SA, CrpeNPV and the mixed infection were 117.5 hours, 113.5 hours and 139.0 hours respectively. The LT90 for CrleGV-SA, CrpeNPV and the mixed infection were 153.2 hours, 159.3, and 193.4 hours respectively. Finally, the composition of OBs recovered from the cadavers produced by the time-response biological assays were investigated by mPCR. A method for extracting gDNA from OBs in neonate-sized T. leucotreta larvae is described. The presence of CrpeNPV along with CrleGV-SA was noted in 4 out of 9 larvae inoculated with only CrleGV-SA. The presence of CrleGV-SA as well as CrpeNPV was noted in all but one larva inoculated with only CrpeNPV, and both CrleGV-SA and CrpeNPV were noted in all but one larva inoculated with a 1:1 mixture of the two, with one larva only being positive for CrleGV-SA. This suggests either stock contamination or the presence of covert infections of CrleGV-SA and CrpeNPV in the T. leucotreta population used in this study. This is the second study to report an improved lethal concentration of a mixed infection of CrleGV-SA and CrpeNPV against T. leucotreta neonates, and the first study to report the slower speed of kill of a mixed infection of CrleGV-SA and CrpeNPV against T. leucotreta neonates. While the improved lethal concentration of the mixed infection is a promising step in the future improvement of baculovirus-based biopesticides, it is at the cost of a slower speed of kill. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
Citizen`s experience of the batho pele principles of consultation and redress in the Buffalo City Metropolitan Municipality
- Authors: Gqamana, Athabile
- Date: 2020-12
- Subjects: Local government -- South Africa , Civil service -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19759 , vital:43235
- Description: Everyday activities of communities are dependent on services provided by the local municipality, district or regional council and the national government. These activities range from water flowing freely from taps, a roof to hide under, and a clean and healthy environment, just to name a few. The Batho Pele principles were introduced to ensure that these services are provided for the benefit of the people. They were introduced to make sure that people are involved in the process of service delivery so that services are exactly what they need. It is important to note that the Batho Pele principles inform service standards and a customer care charter. This means that the government or providers of service listen to citizens’ views and take them into account when making decisions about service delivery. Informing service standards and a customer care charter also means that service providers or the government responds swiftly and sympathetically when the service standard falls below the promised standard. The problem occurs when citizens are not being consulted about the type of services they are entitled to. The citizens of Buffalo City Metropolitan Municipality had an issue with how services are provided. They stated that even though service delivery was improving, the manner in which these services were provided was not satisfactory. They complained that they were not asked about what they needed and what their priorities were. Moreover, they stated that when they complained, they did not receive an effective response. The main objective of this research was to establish citizens’ experience with consultation and redress as core functions of the Batho Pele Principles. Furthermore, this research sought to establish important elements of proper citizen consultation and redress in the literature, to determine the extent to which these principles are adopted in in BCMM, to establish the effects of current consultation and redress practice on citizens’ trust in their local government and to make recommendations on effective approaches to consultation and redress. The theories that guided the study are the agency theory, the social equity theory and the procedural justice as a derivative of social equity theory. The legislative framework includes the White Paper on Transforming Public Service Delivery (Notice No 1954 Of 1994), the Constitution of the Republic of South Africa, the Municipal Systems Act no 32 of 2000 and the Promotion of Administrative Justice Act 3 of 2000. The study used both the qualitative and quantitative methods. It also used a case study design. The study used a sample of 110 respondents and the data was collected using interviews, questionnaires and a focus group discussions. Analysis of data followed the narrative and descriptive paradigms. Most importantly, all the objectives of the study were met. , Thesis (MCom) -- Faculty of Management and Commerce, 2020
- Full Text:
- Date Issued: 2020-12
- Authors: Gqamana, Athabile
- Date: 2020-12
- Subjects: Local government -- South Africa , Civil service -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19759 , vital:43235
- Description: Everyday activities of communities are dependent on services provided by the local municipality, district or regional council and the national government. These activities range from water flowing freely from taps, a roof to hide under, and a clean and healthy environment, just to name a few. The Batho Pele principles were introduced to ensure that these services are provided for the benefit of the people. They were introduced to make sure that people are involved in the process of service delivery so that services are exactly what they need. It is important to note that the Batho Pele principles inform service standards and a customer care charter. This means that the government or providers of service listen to citizens’ views and take them into account when making decisions about service delivery. Informing service standards and a customer care charter also means that service providers or the government responds swiftly and sympathetically when the service standard falls below the promised standard. The problem occurs when citizens are not being consulted about the type of services they are entitled to. The citizens of Buffalo City Metropolitan Municipality had an issue with how services are provided. They stated that even though service delivery was improving, the manner in which these services were provided was not satisfactory. They complained that they were not asked about what they needed and what their priorities were. Moreover, they stated that when they complained, they did not receive an effective response. The main objective of this research was to establish citizens’ experience with consultation and redress as core functions of the Batho Pele Principles. Furthermore, this research sought to establish important elements of proper citizen consultation and redress in the literature, to determine the extent to which these principles are adopted in in BCMM, to establish the effects of current consultation and redress practice on citizens’ trust in their local government and to make recommendations on effective approaches to consultation and redress. The theories that guided the study are the agency theory, the social equity theory and the procedural justice as a derivative of social equity theory. The legislative framework includes the White Paper on Transforming Public Service Delivery (Notice No 1954 Of 1994), the Constitution of the Republic of South Africa, the Municipal Systems Act no 32 of 2000 and the Promotion of Administrative Justice Act 3 of 2000. The study used both the qualitative and quantitative methods. It also used a case study design. The study used a sample of 110 respondents and the data was collected using interviews, questionnaires and a focus group discussions. Analysis of data followed the narrative and descriptive paradigms. Most importantly, all the objectives of the study were met. , Thesis (MCom) -- Faculty of Management and Commerce, 2020
- Full Text:
- Date Issued: 2020-12
The Role of HOP in Emerin-Mediated Nuclear Structure
- Authors: Kituyi, Sarah Naulikha
- Date: 2017
- Subjects: Heat shock proteins , Nuclear structure , Nuclear membranes , Cancer Treatment , Molecular chaperones , Cytoskeleton , Cytoplasm
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/59230 , vital:27485 , DOI 10.21504/10962/59230
- Description: A vital component of the integral nuclear membrane is emerin, a Lamin Emerin and Man1 (LEM) domain protein whose concentration determines the levels of partner proteins that together constitute the structure of the nuclear envelope. Deficiencies in any of these proteins causes the failure of the structure and assembly and disassembly of the nuclear envelope, which disrupts chromosome segregation and nuclear compartmentalization that are both associated with disease. Emerin also localizes in the cytoplasm where it is implicated in the structure of the cytoskeleton via interaction with tubulin and actin and thus its deficiency may equally contribute to the collapse of the cytoskeleton. The Hsp70-Hsp90 organising protein (Hop) functions as a cochaperone for entry of client proteins into the Hsp90 folding cycle. Hop is upregulated in cancer and regulates a number of cell biology processes via interactions with proteins independently of Hsp90. In a previous study using global whole cell mass spectrometry, emerin was shown to be the most significantly down regulated protein in Hop depleted cell lysates. In this current study, it was postulated that emerin interacts with Hop, and this interaction regulates the stability, and level of emerin in the nucleus which impacts on the structure of the nuclear envelope. We used HEK293T cell lines stably expressing shRNA against Hop, emerin and a non-targeting control alongside the over expression of Hop in HEK293 cells to determine the effect of Hop levels on emerin expression and vice versa via Western blotting. The effect of Hop on the localization of emerin was assessed via subcellullar fractionation and confocal microscopy, while the impact on the structure of the nucleus was determined by transmission electron microscopy (TEM). We established that the depletion of Hop using shRNA and the over expression of Hop both result in the proteasomal and lysosomal degradation of emerin. Co-immunoprecipitation assays confirmed that Hop and emerin are in a common complex, which was not dependent on the presence of Hsp90. Loss of Hop or emerin led to a deformation of nuclear structure and a statistically significant decrease in nuclear size compared to control cells and was associated with an increase in the levels of nuclear protein, lamin A-C. Loss of emerin and Hop resulted in increased long term cell survival, but only after restriction of the nucleus when the cells had migrated across a transwell membrane. Taken together, the results obtained suggest that Hop acts as a scaffold for the stabilization of emerin and that the effects of Hop depletion on the structure of the nucleus and long term survival are mediated via the depletion of emerin. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2017
- Full Text:
- Date Issued: 2017
- Authors: Kituyi, Sarah Naulikha
- Date: 2017
- Subjects: Heat shock proteins , Nuclear structure , Nuclear membranes , Cancer Treatment , Molecular chaperones , Cytoskeleton , Cytoplasm
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/59230 , vital:27485 , DOI 10.21504/10962/59230
- Description: A vital component of the integral nuclear membrane is emerin, a Lamin Emerin and Man1 (LEM) domain protein whose concentration determines the levels of partner proteins that together constitute the structure of the nuclear envelope. Deficiencies in any of these proteins causes the failure of the structure and assembly and disassembly of the nuclear envelope, which disrupts chromosome segregation and nuclear compartmentalization that are both associated with disease. Emerin also localizes in the cytoplasm where it is implicated in the structure of the cytoskeleton via interaction with tubulin and actin and thus its deficiency may equally contribute to the collapse of the cytoskeleton. The Hsp70-Hsp90 organising protein (Hop) functions as a cochaperone for entry of client proteins into the Hsp90 folding cycle. Hop is upregulated in cancer and regulates a number of cell biology processes via interactions with proteins independently of Hsp90. In a previous study using global whole cell mass spectrometry, emerin was shown to be the most significantly down regulated protein in Hop depleted cell lysates. In this current study, it was postulated that emerin interacts with Hop, and this interaction regulates the stability, and level of emerin in the nucleus which impacts on the structure of the nuclear envelope. We used HEK293T cell lines stably expressing shRNA against Hop, emerin and a non-targeting control alongside the over expression of Hop in HEK293 cells to determine the effect of Hop levels on emerin expression and vice versa via Western blotting. The effect of Hop on the localization of emerin was assessed via subcellullar fractionation and confocal microscopy, while the impact on the structure of the nucleus was determined by transmission electron microscopy (TEM). We established that the depletion of Hop using shRNA and the over expression of Hop both result in the proteasomal and lysosomal degradation of emerin. Co-immunoprecipitation assays confirmed that Hop and emerin are in a common complex, which was not dependent on the presence of Hsp90. Loss of Hop or emerin led to a deformation of nuclear structure and a statistically significant decrease in nuclear size compared to control cells and was associated with an increase in the levels of nuclear protein, lamin A-C. Loss of emerin and Hop resulted in increased long term cell survival, but only after restriction of the nucleus when the cells had migrated across a transwell membrane. Taken together, the results obtained suggest that Hop acts as a scaffold for the stabilization of emerin and that the effects of Hop depletion on the structure of the nucleus and long term survival are mediated via the depletion of emerin. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2017
- Full Text:
- Date Issued: 2017
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