Design, synthesis, characterization and evaluation of Chitosan-based hydrogel for controlled drug delivery system
- Authors: Safari, Justin Bazibuhe
- Date: 2022-04
- Subjects: Chitosan , Drug delivery systems , Drugs Controlled release , Tenofovir , Colloids , Hepatitis B Chemotherapy , Hydrogel
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232182 , vital:49969
- Description: Hepatitis B infection is a deadly infectious disease caused by the hepatitis B virus and is responsible for many deaths every year worldwide. Despite medication and vaccines against hepatitis B infection, it still presents high morbidity and mortality among populations. This is partly due to factors such as a long medication period of the existing treatments, resulting in poor patient compliance and leading to treatment failure. In addition, this situation can be responsible for the observed emerging drug resistance. Hence, novel drugs and drug delivery systems are needed to tackle this matter. Many strategies have been used to develop long-acting drug delivery systems treatment for several infectious diseases. Hydrogel drug delivery systems have shown interesting results as controlled drug delivery systems for several drugs. Therefore, the present study aimed to develop chitosan grafted poly (acrylamide-co-acrylic acid) hydrogel and apply it as a pH-sensitive controlled delivery system of tenofovir disoproxil fumarate (TDF). TDF is a nucleoside reverse transcriptase inhibitor used as first-line treatment of hepatitis B chronic infection and in the treatment of other viral infections. The free-radical polymerization method was utilized to modify chitosan by grafting acrylamide and acrylic acid and using N, N’-methylene bisacrylamide as the crosslinking agent to prepare the hydrogel, followed by an optimization of parameters that could affect the swelling capacity. The prepared chitosan-g-poly(acrylamide-co-acrylic acid) hydrogel was characterized using Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy (SEM), and was evaluated for cytotoxicity using a HeLa cell assay. TDF was used as a drug model, it was loaded by the swelling equilibrium method, following by the investigation of the release profile of TDF-loaded hydrogel at pH 1.2 and 7.4. A successful synthesis of chitosan grafted poly(acrylamide-co-acrylic acid) hydrogel was confirmed by Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction Spectroscopy (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM). Optimization results showed that the ratio of monomers impacted the swelling ratio of the hydrogel and both the concentration of the crosslinking agent, and the reaction initiator also affected the swelling ratio. The synthesized hydrogels were sensitive to pH and ionic strength. Hydrogel swelling was lower in acidic solutions and higher in neutral and basic solutions and decreased with the increasing ionic strength. Furthermore, SEM results revealed that hydrogel have a rough and fibrous surface structure with numerous pores. Cytotoxicity studies demonstrated that the hydrogel was non-cytotoxic at 50 μg/ml against HeLa cells which suggested a good biocompatibility of the material. TDF was loaded and released from the hydrogels and showed an encapsulation efficiency and drug loading percentage ranging from 81-96% and 8-10%, respectively. TDF release profile was found to be low in buffer solution of pH 1.2 (in the range of 5-10%) and much higher (38-53%) at pH 7.4 within 96 hours. TDF maintained its chemical integrity after release and the hydrogels can therefore be proposed as a new controlled-release drug delivery system for hepatitis B treatment. , Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Safari, Justin Bazibuhe
- Date: 2022-04
- Subjects: Chitosan , Drug delivery systems , Drugs Controlled release , Tenofovir , Colloids , Hepatitis B Chemotherapy , Hydrogel
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232182 , vital:49969
- Description: Hepatitis B infection is a deadly infectious disease caused by the hepatitis B virus and is responsible for many deaths every year worldwide. Despite medication and vaccines against hepatitis B infection, it still presents high morbidity and mortality among populations. This is partly due to factors such as a long medication period of the existing treatments, resulting in poor patient compliance and leading to treatment failure. In addition, this situation can be responsible for the observed emerging drug resistance. Hence, novel drugs and drug delivery systems are needed to tackle this matter. Many strategies have been used to develop long-acting drug delivery systems treatment for several infectious diseases. Hydrogel drug delivery systems have shown interesting results as controlled drug delivery systems for several drugs. Therefore, the present study aimed to develop chitosan grafted poly (acrylamide-co-acrylic acid) hydrogel and apply it as a pH-sensitive controlled delivery system of tenofovir disoproxil fumarate (TDF). TDF is a nucleoside reverse transcriptase inhibitor used as first-line treatment of hepatitis B chronic infection and in the treatment of other viral infections. The free-radical polymerization method was utilized to modify chitosan by grafting acrylamide and acrylic acid and using N, N’-methylene bisacrylamide as the crosslinking agent to prepare the hydrogel, followed by an optimization of parameters that could affect the swelling capacity. The prepared chitosan-g-poly(acrylamide-co-acrylic acid) hydrogel was characterized using Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy (SEM), and was evaluated for cytotoxicity using a HeLa cell assay. TDF was used as a drug model, it was loaded by the swelling equilibrium method, following by the investigation of the release profile of TDF-loaded hydrogel at pH 1.2 and 7.4. A successful synthesis of chitosan grafted poly(acrylamide-co-acrylic acid) hydrogel was confirmed by Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction Spectroscopy (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM). Optimization results showed that the ratio of monomers impacted the swelling ratio of the hydrogel and both the concentration of the crosslinking agent, and the reaction initiator also affected the swelling ratio. The synthesized hydrogels were sensitive to pH and ionic strength. Hydrogel swelling was lower in acidic solutions and higher in neutral and basic solutions and decreased with the increasing ionic strength. Furthermore, SEM results revealed that hydrogel have a rough and fibrous surface structure with numerous pores. Cytotoxicity studies demonstrated that the hydrogel was non-cytotoxic at 50 μg/ml against HeLa cells which suggested a good biocompatibility of the material. TDF was loaded and released from the hydrogels and showed an encapsulation efficiency and drug loading percentage ranging from 81-96% and 8-10%, respectively. TDF release profile was found to be low in buffer solution of pH 1.2 (in the range of 5-10%) and much higher (38-53%) at pH 7.4 within 96 hours. TDF maintained its chemical integrity after release and the hydrogels can therefore be proposed as a new controlled-release drug delivery system for hepatitis B treatment. , Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04
Development of a distributed optical fiber sensor for geological applications
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
Effect of fire severity on Afrotemperate forest tree survival
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55385 , vital:51988
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broadleaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text: false
- Date Issued: 2022-04
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55385 , vital:51988
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broadleaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text: false
- Date Issued: 2022-04
Encapsulation of flame retardants for lithium-ion battery safety
- Authors: Ntombela, Nompilo Princess
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55412 , vital:51993
- Description: Lithium-ion technology takes the lead in electric mobility systems, resulting in an increase in the global demand for Li-ion batteries; however, these batteries are associated with numerous safety concerns. Additionally, there are high costs, high energy and power issues which are some of its key limitations. Research efforts are focused on overcoming these obstacles, with different approaches being explored, such as the investigation of more stable salts, modification of active materials and organic solvents, and the use of electrolyte additives. This study focused specifically on electrolyte additives since the electrolyte is one of the most unstable components of the battery. The electrolyte’s decomposition is one of the reactions that occur inside a battery, which may occur due to overcharging or due to an internal short circuit, amongst others. The electrolyte’s decomposition occurs at the early stages of the thermal runaway process and forms part of the reactions that lead to fires and explosions. Thus, this research aims to develop suitable electrolyte additives to improve the safety aspects of Li-ion batteries. Flame retardant additives show great promise in reducing the flammability of the electrolyte in Li-ion batteries, since they serve to suppress the chemical reactions associated with battery ignition. They retard the fires by scavenging the active radical species formed during the decomposition reaction. In this study, the use of flame retardants was investigated. Flame retardant additives have shown to have flame impeding properties inside a battery; however, their direct addition to the electrolyte tends to cause adverse effects on the ionic conductivity and electrochemical performance of the cells. This study investigated an alternative option - the option to microencapsulate such additives into a neutral compound to ensure that the flame retardant has minimal/no effect on the performance of the battery. This investigation looked at tris(2-butoxyethyl) phosphate (TBP) and bis(2,2,2-trifluoroethyl) methylphosphonate (BFP) as flame retardant additives for the electrolyte. The TBP and BFP flame retardants were microencapsulated in poly(urea formaldehyde) (PUF) coating material via in situ polymerization method. The capsules were characterized using various analytical techniques - to prove it was successfully encapsulated. Electrochemical studies were further done on the capsules and neat flame retardants inside a coin cell. Self-extinguishing time (SET), which is the flammability test, proved that the additives have flame retarding abilities. Opto-digital microscopy (DSX) and scanning electron microscopy (SEM) did confirm the spherical shape of the microcapsules, where SEM also showed the smooth outer layer of the microcapsules and its hollow inner side. Fourier transform infrared spectroscopy (FTIR) proved the presence of the TBP and BFP inside the PUF resin by showing that the chemical composition of microcapsules consisted of both the PUF and flame retardant additives. Simultaneous DSC-TGA (DST) was also performed which showed that the microcapsules were stable before 200 °C, which indicates it would not decompose before the thermal runaway events are occurring. TGA analysis did show that the microcapsules underwent multiple decomposition steps upon heating. Additionally, 31P nuclear magnetic resonance (NMR) was used to quantify the amount of flame retardants additives encapsulated inside PUF shell, and also confirmed the stability of the microcapsules for one month in the electrolyte and at temperatures up to 200 °C. The ionic conductivity was vastly decreased when the flame retardants were added directly to the electrolyte. However, adding the flame retardants in a form of capsules had minimal effect on the ionic conductivity. The cycle capacities of the capsules were also improved when the capsules were added to the cell compared to that of neat flame retardants. The same effect was also noticed when doing Electrochemical Impedance Spectroscopy (EIS). This shows that microencapsulation improves the resistance of the cell caused by the flame retardant in comparison to when added directly to the electrolyte of the cell. , Thesis (MSC) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ntombela, Nompilo Princess
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55412 , vital:51993
- Description: Lithium-ion technology takes the lead in electric mobility systems, resulting in an increase in the global demand for Li-ion batteries; however, these batteries are associated with numerous safety concerns. Additionally, there are high costs, high energy and power issues which are some of its key limitations. Research efforts are focused on overcoming these obstacles, with different approaches being explored, such as the investigation of more stable salts, modification of active materials and organic solvents, and the use of electrolyte additives. This study focused specifically on electrolyte additives since the electrolyte is one of the most unstable components of the battery. The electrolyte’s decomposition is one of the reactions that occur inside a battery, which may occur due to overcharging or due to an internal short circuit, amongst others. The electrolyte’s decomposition occurs at the early stages of the thermal runaway process and forms part of the reactions that lead to fires and explosions. Thus, this research aims to develop suitable electrolyte additives to improve the safety aspects of Li-ion batteries. Flame retardant additives show great promise in reducing the flammability of the electrolyte in Li-ion batteries, since they serve to suppress the chemical reactions associated with battery ignition. They retard the fires by scavenging the active radical species formed during the decomposition reaction. In this study, the use of flame retardants was investigated. Flame retardant additives have shown to have flame impeding properties inside a battery; however, their direct addition to the electrolyte tends to cause adverse effects on the ionic conductivity and electrochemical performance of the cells. This study investigated an alternative option - the option to microencapsulate such additives into a neutral compound to ensure that the flame retardant has minimal/no effect on the performance of the battery. This investigation looked at tris(2-butoxyethyl) phosphate (TBP) and bis(2,2,2-trifluoroethyl) methylphosphonate (BFP) as flame retardant additives for the electrolyte. The TBP and BFP flame retardants were microencapsulated in poly(urea formaldehyde) (PUF) coating material via in situ polymerization method. The capsules were characterized using various analytical techniques - to prove it was successfully encapsulated. Electrochemical studies were further done on the capsules and neat flame retardants inside a coin cell. Self-extinguishing time (SET), which is the flammability test, proved that the additives have flame retarding abilities. Opto-digital microscopy (DSX) and scanning electron microscopy (SEM) did confirm the spherical shape of the microcapsules, where SEM also showed the smooth outer layer of the microcapsules and its hollow inner side. Fourier transform infrared spectroscopy (FTIR) proved the presence of the TBP and BFP inside the PUF resin by showing that the chemical composition of microcapsules consisted of both the PUF and flame retardant additives. Simultaneous DSC-TGA (DST) was also performed which showed that the microcapsules were stable before 200 °C, which indicates it would not decompose before the thermal runaway events are occurring. TGA analysis did show that the microcapsules underwent multiple decomposition steps upon heating. Additionally, 31P nuclear magnetic resonance (NMR) was used to quantify the amount of flame retardants additives encapsulated inside PUF shell, and also confirmed the stability of the microcapsules for one month in the electrolyte and at temperatures up to 200 °C. The ionic conductivity was vastly decreased when the flame retardants were added directly to the electrolyte. However, adding the flame retardants in a form of capsules had minimal effect on the ionic conductivity. The cycle capacities of the capsules were also improved when the capsules were added to the cell compared to that of neat flame retardants. The same effect was also noticed when doing Electrochemical Impedance Spectroscopy (EIS). This shows that microencapsulation improves the resistance of the cell caused by the flame retardant in comparison to when added directly to the electrolyte of the cell. , Thesis (MSC) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Environmental governance, agency and multi-actor dynamics in Southern Africa
- Authors: Falayi, Menelisi
- Date: 2022-04
- Subjects: Environmental law South Africa , Environmental law Zimbabwe , Natural resources Management , Conservation of natural resources South Africa Eastern Cape , Natural resources Co-management South Africa Eastern Cape , Range policy South Africa Eastern Cape , Range management South Africa Eastern Cape , Forest reserves Law and legislation Zimbabwe , Agent (Philosophy)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232355 , vital:49984 , DOI 10.21504/10962/232355
- Description: Natural resources have, since the beginning of time, played a central role in supporting human wellbeing. In southern Africa resource consumption has drastically increased over the past 50 years, resulting in biodiversity loss and land degradation. To reduce land degradation and biodiversity loss rates in the region, great emphasis has been placed on building effective governance structures that can deliver environmentally and socially sustainable outcomes. However, environmental governance continues to be a major challenge in the management and conservation of natural resources in the region. Thus, there is renewed scientific and policy interest in strengthening the capacity of governance systems. This thesis is timely; there is an increasing desire by policymakers and land users in the region to develop governance options that enhance multi-actor participation and collaboration. Therefore, this thesis explores the dynamics that influence the capacity of natural resource governance systems in southern Africa, predominately in Machubeni, South Africa (chapters 3 and 4) and in State forests in Zimbabwe (chapter 5). To achieve this aim, four stand-alone manuscripts that answer the following questions are included: 1. How have governance challenges manifested in natural resource management between 2010 and 2020 in southern Africa? 2. How were the governance objectives and attributes applied per historical period and what were the influencing drivers? a. What key drivers influenced rangeland condition over time in Machubeni? 3. How have multi-actor ties changed since the external investment in landscape governance and management in Machubeni, South Africa? 4. What role has agency played in the effectiveness of co-management initiatives in southern Africa? To answer the questions, I applied Bennett and Satterfield’s practical framework for understanding the objectives, attributes and elements of governance and Archer’s ii morphogenetic framework. The study employed a mixed-methods approach which included a scoping review methodology (chapter 2), household surveys, historical records, life history interviews, focus group discussions (chapters 3 and 4), social network analysis (chapter 4) and secondary data analysis (chapter 5). Results from the scoping review (chapter 2) show that research on governance challenges has not increased since 2010. Results suggest that governance challenges related to the maintenance of system integrity and functioning, specifically lack of coordination, accountability, skills, and resources to define effective natural resource management, were the most reported in the literature. Chapter 3 elucidates the importance of history in evaluating the application of governance objectives and rangeland condition in resource-poor areas. The results show that the residual impacts of the ‘ghost of environmental history’ still influence governance dynamics in Machubeni, South Africa. Furthermore, contemporary challenges are linked to history. Chapter 4 shows that transformative spaces enhance collaboration and knowledge sharing between land users, government, and researchers. Finally, chapter 5 employs the morphogenetic framework to assess how agency (the capacity of people and organisations to make choices and decisions about their lives) influenced the effectiveness of co-management initiatives in southern Africa. The results suggest that in attempts to shift governance towards greater effectiveness, more attention should be paid to building individual and group agency. Based on the results from the empirical chapters, the study identified three key focus areas that require more attention in order to build effective landscape governance and management in southern Africa:(i) acknowledging the role of historical legacies and context,(ii) building and developing agency, capacity and trust amongst actors and (iii) the development of sustainable landscape financing mechanisms that will enable governance systems to deliver socially and environmentally sustainable outcomes. , Ubutyebi bendalo buqhubekile budlala indima ebalulekileyo ekuxhaseni impilo-ntle yoluntu. Ngenxa yokubaluleka kobutyebi bendalo kubomi babantu, ukusetyenziswa kobutyebi kuye kwanda kakhulu kule minyaka eyi-50 idlulileyo, okubangela ulahleko lweentlobo-ntlobo yezityalo nezilwanyana eziphilayo kunye nokhukhuliseko komhlaba kumazantsi e-Afrika. Ukunciphisa ukhukhuliseko komhlaba kunye namazinga alahleko eentlobo-ntlobo zezityalo nezilwanyana eziphilayo kummandla, ugxininiso olukhulu luye lwabekwa ekwakhiweni kweziseko zolawulo ezisebenzayo ezinokuzisa iziphumo ezizinzileyo ngokwemeko yendalo nentlalo. Nangona kunjalo, ulawulo lwendalo lusaqhubeka lungumceli mngeni omkhulu kulawulo nolondolozo lobutyebi bendalo kulo mmandla. Ngoko ke, kukho umdla ohlaziyiweyo wenzululwazi nomgaqo-nkqubo ekomelezeni isakhono seenkqubo zolawulo. Le ithisisi ifike ngexesha kuba kukho umnqweno okhulayo kummandla ngabaqulunqi bomgaqo-nkqubo kunye nabasebenzisi bomhlaba ukuphuhlisa iinketho zolawulo eziphakamisa ukuthatha inxaxheba kwabantu abaninzi kunye nentsebenziswano. Ke ngoko, le ithisisi iphonononga izinto eziphembelela isakhono seenkqubo zolawulo lobutyebi bendalo kumazantsi eAfrika, ikakhulu eMachubeni, eMzantsi Afrika (isahluko 3 no 4) nakumahlathi kaRhulumente eZimbabwe (isahluko 5). Ukuphumeza le njongo, kufakwe layo: 1. Ibonakaliswe njani imiceli mngeni yolawulo kulawulo lwendalo phakathi ko-2010 no 2020 kumazantsi eAfrika? 2. Zeziphi injongo zolawulo kunye neempawu ezisetyenzisiweyo ngokwexesha lembali? a. Zeziphi ezona zinto eziqhuba phambili eziphembelele ukusetyenziswa kweenjongo zolawulo kunye neempawu ngokuhamba kwexesha? b. Zeziphi iindlela ezibalulekileyo ezichaphazele ngayo iimeko zamadlelo ekuhambeni kwexesha? 3. Atshintshe njani amakhonkco obudlelwane phakathi kwabathathi-nxaxheba ukusukela oko kutyalo-mali lwangaphandle kulawulo lobume bomhlaba eMachubeni, eMzantsi Afrika? 4. Yiyiphi indima edlalwe sisakhono sokwenza ukhetho kunye nezigqibo malunga nobomi bakho ekusebenzeni ngempumelelo kwamalinge olawulo ngokubambisana kumazantsi e-Afrika? Ukuphendula imibuzo, ndisebenzise isakhelo esisebenzayo sikaBennett kunye noSatterfield ukuqonda iinjongo kunye neempawu zolawulo kunye nesakhelo se-Archer's morphogenetic. Uphononongo lusebenzise iindlela ezixubeneyo ezibandakanya indlela yokuphonononga iincwadi zophando (isahluko 2), uphando lwamakhaya, iirekhodi zembali, udliwano-ndlebe lwembali yobomi, iingxoxo zeqela eligxininisiweyo (isahluko 3 kunye no 4), uhlalutyo lonxibelelwano nobudlelwane boluntu (isahluko 4) kunye nohlalutyo lwedatha ethathwe ngomnye umntu. (isahluko 5). Iziphumo ezivela kuphononongo lweencwadi zophando (isahluko 2) zibonakalisa ukuba uphando ngemiceli mngeni yolawulo alunyukanga ukusukela ngo-2010. Iziphumo zibonisa ukuba imiceli mngeni yolawulo enxulumene nokugcinwa kwemfezeko nokusebenza kwenkqubo, ngokukodwa ukungabikho kolungelelwaniso, uxanduva, izakhono, kunye nezibonelelo zokuchaza ulawulo lwemithombo yendalo olusebenzayo, yayiyeyona ichazwe kwiincwadi. Isahluko sesi-3 sicacisa ukubaluleka kwembali ekuvavanyeni ukusetyenziswa kweenjongo zolawulo kunye nemeko yemihlaba ekwiindawo ezihlwempuzekileyo ngezibonelelo. Iziphumo zibonisa ukuba uchaphazeleko oshiyekileyo we-‘ghost of environmental history’ zisenefuthe kulawulo lwenguquko eMachubeni, eMzantsi Afrika. Ngaphezu koko, imiceli mngeni yangoku inxulunyaniswa nembali. Isahluko sesi-4 sibonisa ukuba iindawo eziguqulayo ziphucula intsebenziswano nokwabelana ngolwazi phakathi kwabasebenzisi bomhlaba, urhulumente nabaphandi. Ekugqibeleni, isahluko sesi-5 sisebenzisa isakhelo se-morphogenetic ukuvavanya indlela isakhono sabantu kunye nemibutho sokwenza ukhetho kunye nezigqibo malunga nobomi babo ibe nefuthe ekusebenzeni kwamanyathelo olawulo ngokubambisana kumazantsi e-Afrika. Iziphumo zibonisa ukuba kwiinzame zokutshintsha ulawulo ukuze lusebenze kangangoko, ingqwalasela engaphezulu kufuneka ibekwe ekwakheni isakhono, somntu neseqela, sokwenza ukhetho kunye nezigqibo malunga nobomi babo. Ngokusekelwe kwiziphumo ezivela kwizahluko zobungqina, uphononongo luchonge imiba emithathu engundoqo ekugxilwe kuzo ezifuna ingqwalaselo ethe kratya ukuze kwakhiwe ulawulo lwemihlaba olusebenzayo kumazantsi e-Afrika. Ngokukodwa: (i) ukuqaphela indima yelifa lembali kunye nomxholo (ii) ukwakha nokuphuhlisa isakhono v sokwenza ukhetho kunye nezigqibo malunga nobomi, isakhono kunye nokuthembana phakathi kwabathathi-nxaxheba kunye (iii) nokuphuhliswa kweendlela ezizinzileyo zenkxaso-mali yendawo eziya kwenza ukuba iinkqubo zolawulo zinike iziphumo ezizinzileyo ngokwentlalo nendalo. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Falayi, Menelisi
- Date: 2022-04
- Subjects: Environmental law South Africa , Environmental law Zimbabwe , Natural resources Management , Conservation of natural resources South Africa Eastern Cape , Natural resources Co-management South Africa Eastern Cape , Range policy South Africa Eastern Cape , Range management South Africa Eastern Cape , Forest reserves Law and legislation Zimbabwe , Agent (Philosophy)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232355 , vital:49984 , DOI 10.21504/10962/232355
- Description: Natural resources have, since the beginning of time, played a central role in supporting human wellbeing. In southern Africa resource consumption has drastically increased over the past 50 years, resulting in biodiversity loss and land degradation. To reduce land degradation and biodiversity loss rates in the region, great emphasis has been placed on building effective governance structures that can deliver environmentally and socially sustainable outcomes. However, environmental governance continues to be a major challenge in the management and conservation of natural resources in the region. Thus, there is renewed scientific and policy interest in strengthening the capacity of governance systems. This thesis is timely; there is an increasing desire by policymakers and land users in the region to develop governance options that enhance multi-actor participation and collaboration. Therefore, this thesis explores the dynamics that influence the capacity of natural resource governance systems in southern Africa, predominately in Machubeni, South Africa (chapters 3 and 4) and in State forests in Zimbabwe (chapter 5). To achieve this aim, four stand-alone manuscripts that answer the following questions are included: 1. How have governance challenges manifested in natural resource management between 2010 and 2020 in southern Africa? 2. How were the governance objectives and attributes applied per historical period and what were the influencing drivers? a. What key drivers influenced rangeland condition over time in Machubeni? 3. How have multi-actor ties changed since the external investment in landscape governance and management in Machubeni, South Africa? 4. What role has agency played in the effectiveness of co-management initiatives in southern Africa? To answer the questions, I applied Bennett and Satterfield’s practical framework for understanding the objectives, attributes and elements of governance and Archer’s ii morphogenetic framework. The study employed a mixed-methods approach which included a scoping review methodology (chapter 2), household surveys, historical records, life history interviews, focus group discussions (chapters 3 and 4), social network analysis (chapter 4) and secondary data analysis (chapter 5). Results from the scoping review (chapter 2) show that research on governance challenges has not increased since 2010. Results suggest that governance challenges related to the maintenance of system integrity and functioning, specifically lack of coordination, accountability, skills, and resources to define effective natural resource management, were the most reported in the literature. Chapter 3 elucidates the importance of history in evaluating the application of governance objectives and rangeland condition in resource-poor areas. The results show that the residual impacts of the ‘ghost of environmental history’ still influence governance dynamics in Machubeni, South Africa. Furthermore, contemporary challenges are linked to history. Chapter 4 shows that transformative spaces enhance collaboration and knowledge sharing between land users, government, and researchers. Finally, chapter 5 employs the morphogenetic framework to assess how agency (the capacity of people and organisations to make choices and decisions about their lives) influenced the effectiveness of co-management initiatives in southern Africa. The results suggest that in attempts to shift governance towards greater effectiveness, more attention should be paid to building individual and group agency. Based on the results from the empirical chapters, the study identified three key focus areas that require more attention in order to build effective landscape governance and management in southern Africa:(i) acknowledging the role of historical legacies and context,(ii) building and developing agency, capacity and trust amongst actors and (iii) the development of sustainable landscape financing mechanisms that will enable governance systems to deliver socially and environmentally sustainable outcomes. , Ubutyebi bendalo buqhubekile budlala indima ebalulekileyo ekuxhaseni impilo-ntle yoluntu. Ngenxa yokubaluleka kobutyebi bendalo kubomi babantu, ukusetyenziswa kobutyebi kuye kwanda kakhulu kule minyaka eyi-50 idlulileyo, okubangela ulahleko lweentlobo-ntlobo yezityalo nezilwanyana eziphilayo kunye nokhukhuliseko komhlaba kumazantsi e-Afrika. Ukunciphisa ukhukhuliseko komhlaba kunye namazinga alahleko eentlobo-ntlobo zezityalo nezilwanyana eziphilayo kummandla, ugxininiso olukhulu luye lwabekwa ekwakhiweni kweziseko zolawulo ezisebenzayo ezinokuzisa iziphumo ezizinzileyo ngokwemeko yendalo nentlalo. Nangona kunjalo, ulawulo lwendalo lusaqhubeka lungumceli mngeni omkhulu kulawulo nolondolozo lobutyebi bendalo kulo mmandla. Ngoko ke, kukho umdla ohlaziyiweyo wenzululwazi nomgaqo-nkqubo ekomelezeni isakhono seenkqubo zolawulo. Le ithisisi ifike ngexesha kuba kukho umnqweno okhulayo kummandla ngabaqulunqi bomgaqo-nkqubo kunye nabasebenzisi bomhlaba ukuphuhlisa iinketho zolawulo eziphakamisa ukuthatha inxaxheba kwabantu abaninzi kunye nentsebenziswano. Ke ngoko, le ithisisi iphonononga izinto eziphembelela isakhono seenkqubo zolawulo lobutyebi bendalo kumazantsi eAfrika, ikakhulu eMachubeni, eMzantsi Afrika (isahluko 3 no 4) nakumahlathi kaRhulumente eZimbabwe (isahluko 5). Ukuphumeza le njongo, kufakwe layo: 1. Ibonakaliswe njani imiceli mngeni yolawulo kulawulo lwendalo phakathi ko-2010 no 2020 kumazantsi eAfrika? 2. Zeziphi injongo zolawulo kunye neempawu ezisetyenzisiweyo ngokwexesha lembali? a. Zeziphi ezona zinto eziqhuba phambili eziphembelele ukusetyenziswa kweenjongo zolawulo kunye neempawu ngokuhamba kwexesha? b. Zeziphi iindlela ezibalulekileyo ezichaphazele ngayo iimeko zamadlelo ekuhambeni kwexesha? 3. Atshintshe njani amakhonkco obudlelwane phakathi kwabathathi-nxaxheba ukusukela oko kutyalo-mali lwangaphandle kulawulo lobume bomhlaba eMachubeni, eMzantsi Afrika? 4. Yiyiphi indima edlalwe sisakhono sokwenza ukhetho kunye nezigqibo malunga nobomi bakho ekusebenzeni ngempumelelo kwamalinge olawulo ngokubambisana kumazantsi e-Afrika? Ukuphendula imibuzo, ndisebenzise isakhelo esisebenzayo sikaBennett kunye noSatterfield ukuqonda iinjongo kunye neempawu zolawulo kunye nesakhelo se-Archer's morphogenetic. Uphononongo lusebenzise iindlela ezixubeneyo ezibandakanya indlela yokuphonononga iincwadi zophando (isahluko 2), uphando lwamakhaya, iirekhodi zembali, udliwano-ndlebe lwembali yobomi, iingxoxo zeqela eligxininisiweyo (isahluko 3 kunye no 4), uhlalutyo lonxibelelwano nobudlelwane boluntu (isahluko 4) kunye nohlalutyo lwedatha ethathwe ngomnye umntu. (isahluko 5). Iziphumo ezivela kuphononongo lweencwadi zophando (isahluko 2) zibonakalisa ukuba uphando ngemiceli mngeni yolawulo alunyukanga ukusukela ngo-2010. Iziphumo zibonisa ukuba imiceli mngeni yolawulo enxulumene nokugcinwa kwemfezeko nokusebenza kwenkqubo, ngokukodwa ukungabikho kolungelelwaniso, uxanduva, izakhono, kunye nezibonelelo zokuchaza ulawulo lwemithombo yendalo olusebenzayo, yayiyeyona ichazwe kwiincwadi. Isahluko sesi-3 sicacisa ukubaluleka kwembali ekuvavanyeni ukusetyenziswa kweenjongo zolawulo kunye nemeko yemihlaba ekwiindawo ezihlwempuzekileyo ngezibonelelo. Iziphumo zibonisa ukuba uchaphazeleko oshiyekileyo we-‘ghost of environmental history’ zisenefuthe kulawulo lwenguquko eMachubeni, eMzantsi Afrika. Ngaphezu koko, imiceli mngeni yangoku inxulunyaniswa nembali. Isahluko sesi-4 sibonisa ukuba iindawo eziguqulayo ziphucula intsebenziswano nokwabelana ngolwazi phakathi kwabasebenzisi bomhlaba, urhulumente nabaphandi. Ekugqibeleni, isahluko sesi-5 sisebenzisa isakhelo se-morphogenetic ukuvavanya indlela isakhono sabantu kunye nemibutho sokwenza ukhetho kunye nezigqibo malunga nobomi babo ibe nefuthe ekusebenzeni kwamanyathelo olawulo ngokubambisana kumazantsi e-Afrika. Iziphumo zibonisa ukuba kwiinzame zokutshintsha ulawulo ukuze lusebenze kangangoko, ingqwalasela engaphezulu kufuneka ibekwe ekwakheni isakhono, somntu neseqela, sokwenza ukhetho kunye nezigqibo malunga nobomi babo. Ngokusekelwe kwiziphumo ezivela kwizahluko zobungqina, uphononongo luchonge imiba emithathu engundoqo ekugxilwe kuzo ezifuna ingqwalaselo ethe kratya ukuze kwakhiwe ulawulo lwemihlaba olusebenzayo kumazantsi e-Afrika. Ngokukodwa: (i) ukuqaphela indima yelifa lembali kunye nomxholo (ii) ukwakha nokuphuhlisa isakhono v sokwenza ukhetho kunye nezigqibo malunga nobomi, isakhono kunye nokuthembana phakathi kwabathathi-nxaxheba kunye (iii) nokuphuhliswa kweendlela ezizinzileyo zenkxaso-mali yendawo eziya kwenza ukuba iinkqubo zolawulo zinike iziphumo ezizinzileyo ngokwentlalo nendalo. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04
Evaluation of groundwater potential using geological and geophysical methods in the University of Fort Hare Alice Campus, Eastern Cape Province of South Africa
- Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Exploring the adaptation challenges faced by novice foundation phase teachers in the Nelson Mandela Metropole
- Authors: Grimbeek, Michelle Louise
- Date: 2022-04
- Subjects: First year teachers , Teachers -- Training of – South Africa – Nelson Mandela Municipality , Education, Primary -- South Africa -- Nelson Mandela Municipality
- Language: English
- Type: Master's theses , Thesis
- Identifier: http://hdl.handle.net/10948/56034 , vital:54941
- Description: The challenges faced by novice teachers have been widely discussed in the last decade (Caspersen & Raaen, 2014; Burkman, 2012). It is believed that the first year of teaching is found to be exceedingly challenging to the novice teacher due to the complex demands of the profession, as well as a result of a lack of training and induction into the work environment (Burkman, 2012). Researchers highlight that some of the many challenges that novice teachers experience are shortcomings in curricular planning, classroom management and discipline, instructional techniques, access to materials, and dealing with parents (Burkman, 2012). These challenges, along with feelings of inadequacy due to lack of experience in the working world, often have a negative effect on novice teachers and their ability to cope, subsequently resulting in high stress levels and burnout (Caspersen & Raaen, 2014). This qualitative study incorporated an interpretivist paradigm and used both semistructured interviews and a focus group discussion to explore the adaptation challenges experienced by novice Foundation Phase teachers in the Nelson Mandela Metropole. Grossman‟s Teacher Knowledge Theory and Vygotsky‟s Social Constructivist Theory were used to frame and make meaning of the findings of this study. The findings of this study indicate that novice teachers experience a range of challenges upon entering the working world. The numerous factors influencing these challenges experienced by novices include: the work environment; prior training and education; personal knowledge, values and attitudes toward teaching; and professional and social support received within the workplace. These findings were used to formulate guidelines to help support novice teachers in their adaptation from university to the professional work environment. , Thesis (MEd) -- Faculty of Education, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Grimbeek, Michelle Louise
- Date: 2022-04
- Subjects: First year teachers , Teachers -- Training of – South Africa – Nelson Mandela Municipality , Education, Primary -- South Africa -- Nelson Mandela Municipality
- Language: English
- Type: Master's theses , Thesis
- Identifier: http://hdl.handle.net/10948/56034 , vital:54941
- Description: The challenges faced by novice teachers have been widely discussed in the last decade (Caspersen & Raaen, 2014; Burkman, 2012). It is believed that the first year of teaching is found to be exceedingly challenging to the novice teacher due to the complex demands of the profession, as well as a result of a lack of training and induction into the work environment (Burkman, 2012). Researchers highlight that some of the many challenges that novice teachers experience are shortcomings in curricular planning, classroom management and discipline, instructional techniques, access to materials, and dealing with parents (Burkman, 2012). These challenges, along with feelings of inadequacy due to lack of experience in the working world, often have a negative effect on novice teachers and their ability to cope, subsequently resulting in high stress levels and burnout (Caspersen & Raaen, 2014). This qualitative study incorporated an interpretivist paradigm and used both semistructured interviews and a focus group discussion to explore the adaptation challenges experienced by novice Foundation Phase teachers in the Nelson Mandela Metropole. Grossman‟s Teacher Knowledge Theory and Vygotsky‟s Social Constructivist Theory were used to frame and make meaning of the findings of this study. The findings of this study indicate that novice teachers experience a range of challenges upon entering the working world. The numerous factors influencing these challenges experienced by novices include: the work environment; prior training and education; personal knowledge, values and attitudes toward teaching; and professional and social support received within the workplace. These findings were used to formulate guidelines to help support novice teachers in their adaptation from university to the professional work environment. , Thesis (MEd) -- Faculty of Education, 2022
- Full Text:
- Date Issued: 2022-04
Exploring the nature and scope of food insecurity among postgraduate students: a case of Nelson Mandela University
- Authors: Kuguyo, Yeukai T
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55348 , vital:51916
- Description: This study explores the nature and scope of food insecurity among postgraduate students at Nelson Mandela University, South Africa. The study employed a mixed method approach to access postgraduate students and university officials to investigate the prevalence of food insecurity. The approach also assesses the demographic factors; academic and mental implications along with the coping mechanisms associated with the experiences of food insecurity in higher education South Africa. The study incorporates an adapted conceptual framework from Alaimo’s food insecurity socio-economic risk models (2005) to understand the higher education context. Alaimo’s model seeks to connect the household conditions and broader systematic socio-economic mechanisms that households adopt to secure food. This model was adapted and employed in understanding the data collected while using a mixed-method approach between June and August 2021. The study employed an online survey for only postgraduate students enrolled at Nelson Mandela University (NMU) during the time of the study. This was supplemented by semi-structured interviews with student affairs officials that are directly involved in the formulation of strategies used to alleviate food insecurity at NMU. With 78 postgraduate students responding to the online survey, the study seems to confirm some of the studies done in this field on the inadequacy of food banks and food gardens in addressing food challenges effectively on campus. Similarly, the study found that the experiences of food insecurity were prevalent amongst postgraduate students that identified as black, low-income, and making access of the campus clinic for food relief. The study concluded by recommending a collaborative and a multi-level systematic approach in alleviating food insecurity in higher education. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Kuguyo, Yeukai T
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55348 , vital:51916
- Description: This study explores the nature and scope of food insecurity among postgraduate students at Nelson Mandela University, South Africa. The study employed a mixed method approach to access postgraduate students and university officials to investigate the prevalence of food insecurity. The approach also assesses the demographic factors; academic and mental implications along with the coping mechanisms associated with the experiences of food insecurity in higher education South Africa. The study incorporates an adapted conceptual framework from Alaimo’s food insecurity socio-economic risk models (2005) to understand the higher education context. Alaimo’s model seeks to connect the household conditions and broader systematic socio-economic mechanisms that households adopt to secure food. This model was adapted and employed in understanding the data collected while using a mixed-method approach between June and August 2021. The study employed an online survey for only postgraduate students enrolled at Nelson Mandela University (NMU) during the time of the study. This was supplemented by semi-structured interviews with student affairs officials that are directly involved in the formulation of strategies used to alleviate food insecurity at NMU. With 78 postgraduate students responding to the online survey, the study seems to confirm some of the studies done in this field on the inadequacy of food banks and food gardens in addressing food challenges effectively on campus. Similarly, the study found that the experiences of food insecurity were prevalent amongst postgraduate students that identified as black, low-income, and making access of the campus clinic for food relief. The study concluded by recommending a collaborative and a multi-level systematic approach in alleviating food insecurity in higher education. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Exploring the spiritual meaning of water among Amaxhosa: The study of spiritual practices in Isinuka
- Authors: Menye, Nomtha
- Date: 2022-04
- Subjects: Healing waters -- Eastern Cape , Xhosa (African people) --Religion -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55811 , vital:53885
- Description: This study explores the spiritual relationship of water and uluntu lwase (people of) Port St. Johns, Eastern Cape, South Africa. Particularly the people that reside or regularly visit Isinuka sacred springs. This is done through an analysis and observations of the ritual practises performed at Isinuka sacred springs in Port St. Johns. This spring has provided sacred water used for healing, cleansing, and drinking for decades. Therefore, in this research we use the sacred water as an analysis point to understand the genesis of the ecological relationship of indigenous people and the environment. More so, this study uses the sacred water of the spring as an access point into indigenous knowledge systems (IKS) that have been passed on and maintained throughout history by the African elders. µRitual archives¶ have proved to carry indigenous knowledge systems on the history and philosophies of native regions and countries. Therefore, folktales, rituals, idioms and songs are didactic, and were intended to teach and sustain Isintu sakwa Xhosa (customs). This study uses observations ritual practises and face to face interviews to uncover the importance of nature and indigenous understanding of the environment from AmaXhosa residing in this area. The study was conducted in Port St. Johns in the rural parts of the Eastern Cape. Port St. Johns is a region of residing amaMpondo, which is an isiXhosa dialect. Therefore, amaMpondo and AmaXhosa are used in the study interchangeably. The researcher spent weeks visiting the spring daily and conducting qualitative semi-structured interviews. Observations and partaking in rituals were also used as a methodological approach to understand and capture the full experience of the sacred spring. The study uses the concept of as a medium to examine the relationship of water to spiritual ritual practises. The study literature shows a huge disjuncture between the literature written about the spring and the sociological meaning of the spring to the people that visit the spring. The results showed that the healing properties in the spring were caused by elements such as sulphur(s) and not the only the ritual practises that are performed at the spring. The study shows that, it is in the ritual practises that native Africans show their knowledge of the historical cosmological relationship between people and the environment. This is indicated in their use of sacred sites such as caves, rivers and ocean water to communicate with their ancestors. This study hopes to contribute towards a richer understanding of spirituality, ritual and archival work, for a holistic policymaking when dealing with water policies through an inclusive African indigenous perspective. , Thesis (MA) -- Faculty of Humanities, School of Sociology and anthropology, 2022
- Full Text:
- Date Issued: 2022-04
Exploring the spiritual meaning of water among Amaxhosa: The study of spiritual practices in Isinuka
- Authors: Menye, Nomtha
- Date: 2022-04
- Subjects: Healing waters -- Eastern Cape , Xhosa (African people) --Religion -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55811 , vital:53885
- Description: This study explores the spiritual relationship of water and uluntu lwase (people of) Port St. Johns, Eastern Cape, South Africa. Particularly the people that reside or regularly visit Isinuka sacred springs. This is done through an analysis and observations of the ritual practises performed at Isinuka sacred springs in Port St. Johns. This spring has provided sacred water used for healing, cleansing, and drinking for decades. Therefore, in this research we use the sacred water as an analysis point to understand the genesis of the ecological relationship of indigenous people and the environment. More so, this study uses the sacred water of the spring as an access point into indigenous knowledge systems (IKS) that have been passed on and maintained throughout history by the African elders. µRitual archives¶ have proved to carry indigenous knowledge systems on the history and philosophies of native regions and countries. Therefore, folktales, rituals, idioms and songs are didactic, and were intended to teach and sustain Isintu sakwa Xhosa (customs). This study uses observations ritual practises and face to face interviews to uncover the importance of nature and indigenous understanding of the environment from AmaXhosa residing in this area. The study was conducted in Port St. Johns in the rural parts of the Eastern Cape. Port St. Johns is a region of residing amaMpondo, which is an isiXhosa dialect. Therefore, amaMpondo and AmaXhosa are used in the study interchangeably. The researcher spent weeks visiting the spring daily and conducting qualitative semi-structured interviews. Observations and partaking in rituals were also used as a methodological approach to understand and capture the full experience of the sacred spring. The study uses the concept of as a medium to examine the relationship of water to spiritual ritual practises. The study literature shows a huge disjuncture between the literature written about the spring and the sociological meaning of the spring to the people that visit the spring. The results showed that the healing properties in the spring were caused by elements such as sulphur(s) and not the only the ritual practises that are performed at the spring. The study shows that, it is in the ritual practises that native Africans show their knowledge of the historical cosmological relationship between people and the environment. This is indicated in their use of sacred sites such as caves, rivers and ocean water to communicate with their ancestors. This study hopes to contribute towards a richer understanding of spirituality, ritual and archival work, for a holistic policymaking when dealing with water policies through an inclusive African indigenous perspective. , Thesis (MA) -- Faculty of Humanities, School of Sociology and anthropology, 2022
- Full Text:
- Date Issued: 2022-04
Factors that influence customers’ spaza shopping experience
- Authors: Yase, Tembelihle
- Date: 2022-04
- Subjects: Home-based businesses--South Africa-Port Elizabeth
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55780 , vital:53877
- Description: Spaza shops, originating in South Africa during the 1970’s, often operate in townships, selling products and services to customers who live mostly within walking distance of the shop. Almost five decades later, and spaza shops abound across most townships in South Africa. These businesses not only provide grocery items and services to customers in the township community but are a means for people to earn a livelihood for themselves and also contribute economically through creating employment opportunities in the informal sector. Research about spaza shops shows that there is a growing customer interest in purchasing products and services from spaza shops, and that if spaza shops are to continue growing, they need to be more competitive. Research by renowned authors in the field of experience marketing, Pine and Gilmore (2013) puts forward that experiences are the new relevant economic offering, and an essential value creating platform for businesses to be more competitive. However, before customer experience can be enhanced in spaza shops, it is important to first identify the factors that influence customer experience in a spaza shop context. Considering the latter, the primary objective of this study was to measure factors that influence customer experience in spaza shops. A descriptive research design was selected for this study, followed by a positivistic research paradigm and quantitative research methodology. Secondary data was collected through articles, journals, books and from newspapers. Primary data was collected using a survey in the form of a self-administered questionnaire. The target population for this study was customers who are older than 18 years, who had bought grocery items (products and services) in spaza shops located in Nelson Mandela Bay townships specifically in Walmer Township, KwaZakhele, Zwide, Motherwell, KwaMagxaki and New Brighton. A non-probability sampling method and convenience sampling technique were used to distribute a total of 200 selfadministered questionnaires. Once the data collection phase was completed, the data from the questionnaires was recorded, coded, and cleaned on a single excel spreadsheet. After the latter was done, a total of 185 questionnaires were deemed useable and considered for data analysis, which was conducted with the aid of IBM SPSS Statistics version 27 (computer software). , Thesis (MCom) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Yase, Tembelihle
- Date: 2022-04
- Subjects: Home-based businesses--South Africa-Port Elizabeth
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55780 , vital:53877
- Description: Spaza shops, originating in South Africa during the 1970’s, often operate in townships, selling products and services to customers who live mostly within walking distance of the shop. Almost five decades later, and spaza shops abound across most townships in South Africa. These businesses not only provide grocery items and services to customers in the township community but are a means for people to earn a livelihood for themselves and also contribute economically through creating employment opportunities in the informal sector. Research about spaza shops shows that there is a growing customer interest in purchasing products and services from spaza shops, and that if spaza shops are to continue growing, they need to be more competitive. Research by renowned authors in the field of experience marketing, Pine and Gilmore (2013) puts forward that experiences are the new relevant economic offering, and an essential value creating platform for businesses to be more competitive. However, before customer experience can be enhanced in spaza shops, it is important to first identify the factors that influence customer experience in a spaza shop context. Considering the latter, the primary objective of this study was to measure factors that influence customer experience in spaza shops. A descriptive research design was selected for this study, followed by a positivistic research paradigm and quantitative research methodology. Secondary data was collected through articles, journals, books and from newspapers. Primary data was collected using a survey in the form of a self-administered questionnaire. The target population for this study was customers who are older than 18 years, who had bought grocery items (products and services) in spaza shops located in Nelson Mandela Bay townships specifically in Walmer Township, KwaZakhele, Zwide, Motherwell, KwaMagxaki and New Brighton. A non-probability sampling method and convenience sampling technique were used to distribute a total of 200 selfadministered questionnaires. Once the data collection phase was completed, the data from the questionnaires was recorded, coded, and cleaned on a single excel spreadsheet. After the latter was done, a total of 185 questionnaires were deemed useable and considered for data analysis, which was conducted with the aid of IBM SPSS Statistics version 27 (computer software). , Thesis (MCom) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Foraging behaviour of the Sooty Albatross in relation to climatic variability and fisheries
- Authors: Banda, Shamiso
- Date: 2022-04
- Subjects: Spatial behavior in animals , Conservation of natural resources --South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55632 , vital:53383
- Description: As top predators, seabirds occupy the upper trophic level of marine ecosystems. They are consequently important for the maintenance of ecosystem structure and function, while also possessing characteristics which are useful for identifying climate-driven changes in oceanography at all trophic levels. This important faunal group is one of the most threatened, with climate change and fisheries bycatch mortality being the primary drivers of population declines. Understanding these threats is important for the management of threatened seabird populations. One impact of climate change and variability in climate occurs through changes in prey availability. As central place foragers, breeding seabirds have trip duration constraints due to the obligation of nest duties. This makes them particularly vulnerable to changes in prey availability within their foraging ranges. The ability to adjust foraging behaviour during environmental conditions which alter prey availability is an important attribute which can contribute to breeding success. Thus, investigating for this foraging behavioural plasticity during different breeding stages provides insights into how a species is likely to be impacted by climate change. The sooty albatross population on Marion Island was studied and displayed a degree of foraging behavioural plasticity during the five-year period of pronounced climatic variability studied. Incubating birds mainly foraged in the subtropical convergence zone (STCZ), the Sub Antarctic Front (SAF) and Subtropical Front (STF) which border it, and the region north of the STF. Brooding birds mainly used the SAF and Polar Frontal Zone (PFZ). Significantly different areas were used between years during both breeding stages. This population showed a lack of consistent habitat preferences which may offer resilience to progressive climatic variability and change. Interactions of sooty albatrosses, as well as white-chinned petrels for comparative purposes, with fisheries were also assessed. The two species were compared to shed light on possible explanations for differences in seabird-fishery interactions between the species. The impact of fisheries-related mortality (bycatch) is dependent on exposure to fishing activity and attraction to fishing boats encountered while foraging. Bycatch mortality has previously been proposed as the main cause of this sooty albatross population’s decline. Exposure and 6 attraction to fishing boats was found to be lower than that of white-chinned petrels which are bycatch prone. However, the current level of attraction exhibited by this sooty albatross population may expose a significant fraction of the population to bycatch risk due to its small population size. Additionally, all fishing boats were encountered north of the STF where non breeding individuals are now known to be distributed. Thus, the impact of fisheries on this population may mainly be mediated by more bycatch prone non-breeding individuals. Overall, the relative impact of fisheries bycatch mortality is suggested to be higher than that of climatic impacts on the sooty albatross population on Marion Island. However, this study did not incorporate dietary and demographic information which would reveal whether there are nutritional differences between years that may impact on breeding success. An integrated rather than independent assessment of foraging behavioural responses to climatic variability and fishing activity is recommended for improving our understanding of current and future conservation priorities. , Thesis (MSc) -- Faculty of Science, Zoology , 2021
- Full Text:
- Date Issued: 2022-04
- Authors: Banda, Shamiso
- Date: 2022-04
- Subjects: Spatial behavior in animals , Conservation of natural resources --South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55632 , vital:53383
- Description: As top predators, seabirds occupy the upper trophic level of marine ecosystems. They are consequently important for the maintenance of ecosystem structure and function, while also possessing characteristics which are useful for identifying climate-driven changes in oceanography at all trophic levels. This important faunal group is one of the most threatened, with climate change and fisheries bycatch mortality being the primary drivers of population declines. Understanding these threats is important for the management of threatened seabird populations. One impact of climate change and variability in climate occurs through changes in prey availability. As central place foragers, breeding seabirds have trip duration constraints due to the obligation of nest duties. This makes them particularly vulnerable to changes in prey availability within their foraging ranges. The ability to adjust foraging behaviour during environmental conditions which alter prey availability is an important attribute which can contribute to breeding success. Thus, investigating for this foraging behavioural plasticity during different breeding stages provides insights into how a species is likely to be impacted by climate change. The sooty albatross population on Marion Island was studied and displayed a degree of foraging behavioural plasticity during the five-year period of pronounced climatic variability studied. Incubating birds mainly foraged in the subtropical convergence zone (STCZ), the Sub Antarctic Front (SAF) and Subtropical Front (STF) which border it, and the region north of the STF. Brooding birds mainly used the SAF and Polar Frontal Zone (PFZ). Significantly different areas were used between years during both breeding stages. This population showed a lack of consistent habitat preferences which may offer resilience to progressive climatic variability and change. Interactions of sooty albatrosses, as well as white-chinned petrels for comparative purposes, with fisheries were also assessed. The two species were compared to shed light on possible explanations for differences in seabird-fishery interactions between the species. The impact of fisheries-related mortality (bycatch) is dependent on exposure to fishing activity and attraction to fishing boats encountered while foraging. Bycatch mortality has previously been proposed as the main cause of this sooty albatross population’s decline. Exposure and 6 attraction to fishing boats was found to be lower than that of white-chinned petrels which are bycatch prone. However, the current level of attraction exhibited by this sooty albatross population may expose a significant fraction of the population to bycatch risk due to its small population size. Additionally, all fishing boats were encountered north of the STF where non breeding individuals are now known to be distributed. Thus, the impact of fisheries on this population may mainly be mediated by more bycatch prone non-breeding individuals. Overall, the relative impact of fisheries bycatch mortality is suggested to be higher than that of climatic impacts on the sooty albatross population on Marion Island. However, this study did not incorporate dietary and demographic information which would reveal whether there are nutritional differences between years that may impact on breeding success. An integrated rather than independent assessment of foraging behavioural responses to climatic variability and fishing activity is recommended for improving our understanding of current and future conservation priorities. , Thesis (MSc) -- Faculty of Science, Zoology , 2021
- Full Text:
- Date Issued: 2022-04
Grappling with food and livelihood practices in the context of socio-ecological displacement: The case of 2014 Tokwe-Mukorsi flood victims in Chingwizi, Zimbabwe
- Mudefi, Elmon https://orcid.org/0000-0003-3448-5432
- Authors: Mudefi, Elmon https://orcid.org/0000-0003-3448-5432
- Date: 2022-04
- Subjects: Food security , Households , Natural disasters -- Zimbabwe
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22056 , vital:51979
- Description: This study sought to examine how the socio-ecologically displaced Tokwe-Mukorsi community in southern Zimbabwe grappled with adverse circumstances that threatened to obliterate their age-old food and livelihood practices after five years of being resettled 150km away in Chingwizi. The investigation is done against the backdrop of the dominant narrative on resilience, which often overlooks resilience outcomes associated with specific contextual experiences of socio-ecological disadvantage. The study examined the nature and character of emergent food and livelihood practices in Chingwizi, with a view to establishing how they were impacted by socio-political dynamics encountered vis-à-vis displacement, resettlement and in processes of attempting to recover. The study also examined how local narratives about the new food and livelihood practices in Chingwizi intersect with dominant resilience discourses, especially those related to climate change adaptation, sustainability and food security. A triangulated research design was utilised. It consisted of survey, focus group discussion, in-depth interview, and key informant interview. Qualitative research participants were selected based on their knowledge and experience on food and livelihood practices before and after displacement. This included the displaced flood victims that met this criterion, local leaders, government officials and local opinion leaders. The findings revealed that food and livelihood practices in Chingwizi had deteriorated over the five-year period under investigation. This was reflected in a diminution in livestock herds, crop production, income streams and average household monthly incomes. As a result, food insecurity was very high, and households were forced to rely more on donations. The displaced flood victims, however, adapted to the harsh conditions by engaging in a variety of livelihood alternatives, including food vending, buying and selling, craftwork, small livestock rearing, and migrating to neighbouring South Africa to seek employment opportunities. Nevertheless, efforts to rebuild food and livelihood practices were hampered by socio-political dynamics. This resulted in the loss of key livelihood assets, a situation aggravated by compensational injustice, contestations over land and resources by the host communities, dysfunctional social networks, and victims’ cultural ‘fixations’. The study concludes from these and other findings that achieving transformation in the form of adaptation, food security and sustainability following involuntary displacement and resettlement is more than just a question of resilience, and that displacement and resettlement are complex processes that create invidious dynamism for the stakeholders concerned. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mudefi, Elmon https://orcid.org/0000-0003-3448-5432
- Date: 2022-04
- Subjects: Food security , Households , Natural disasters -- Zimbabwe
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22056 , vital:51979
- Description: This study sought to examine how the socio-ecologically displaced Tokwe-Mukorsi community in southern Zimbabwe grappled with adverse circumstances that threatened to obliterate their age-old food and livelihood practices after five years of being resettled 150km away in Chingwizi. The investigation is done against the backdrop of the dominant narrative on resilience, which often overlooks resilience outcomes associated with specific contextual experiences of socio-ecological disadvantage. The study examined the nature and character of emergent food and livelihood practices in Chingwizi, with a view to establishing how they were impacted by socio-political dynamics encountered vis-à-vis displacement, resettlement and in processes of attempting to recover. The study also examined how local narratives about the new food and livelihood practices in Chingwizi intersect with dominant resilience discourses, especially those related to climate change adaptation, sustainability and food security. A triangulated research design was utilised. It consisted of survey, focus group discussion, in-depth interview, and key informant interview. Qualitative research participants were selected based on their knowledge and experience on food and livelihood practices before and after displacement. This included the displaced flood victims that met this criterion, local leaders, government officials and local opinion leaders. The findings revealed that food and livelihood practices in Chingwizi had deteriorated over the five-year period under investigation. This was reflected in a diminution in livestock herds, crop production, income streams and average household monthly incomes. As a result, food insecurity was very high, and households were forced to rely more on donations. The displaced flood victims, however, adapted to the harsh conditions by engaging in a variety of livelihood alternatives, including food vending, buying and selling, craftwork, small livestock rearing, and migrating to neighbouring South Africa to seek employment opportunities. Nevertheless, efforts to rebuild food and livelihood practices were hampered by socio-political dynamics. This resulted in the loss of key livelihood assets, a situation aggravated by compensational injustice, contestations over land and resources by the host communities, dysfunctional social networks, and victims’ cultural ‘fixations’. The study concludes from these and other findings that achieving transformation in the form of adaptation, food security and sustainability following involuntary displacement and resettlement is more than just a question of resilience, and that displacement and resettlement are complex processes that create invidious dynamism for the stakeholders concerned. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022-04
Household food waste generation, disposal and minimisation in two South African towns
- Authors: Mtakati, Sinako
- Date: 2022-04
- Subjects: Food waste South Africa Cradock , Food waste South Africa Middelburg (Eastern Cape) , Sanitary landfills Environmental aspects South Africa , Greenhouse gases Environmental aspects South Africa , Income distribution South Africa , Socio-economic status South Africa , Waste minimization South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232159 , vital:49967
- Description: Food waste is becoming an important issue considering greenhouse gas emissions from landfills. However, data on the quantities of food disposed remains limited, especially for developing, countries including South Africa. Global food waste estimates suggest that households in developed countries waste more food than those in developing countries. Further, research shows that lack of food waste management impacts negatively on the global efforts to combat food waste generation. I therefore set out to present primary data relating to household food waste generation and minimisation within a South African context. The case study covers two towns in the Eastern Cape province, namely Cradock and Middelburg, with a combined population of 55 352 people. Household food waste assessment and quantification was undertaken using two methods, 1) questionnaires to explore quantities of different types of food wasted by households, and 2) kitchen scales to measure the amounts of food discarded by households. Participating households in each suburb were selected randomly. Differences in shopping and household food waste behaviour in households from different income suburbs is vital to understand as it sets an effective approach to food waste interventions that might have a positive impact in minimising food waste generation. In this thesis, differences in shopping and household food waste behaviour across households in the affluent, middle and low-income suburbs is uncovered. A questionnaire was conducted and households in the affluent suburbs purchased food more frequently and had the highest percentage of respondents that used shopping list when buying food than those in the middle and low-income suburbs. The thesis also indicates that households in the low-income suburbs were more attracted to food special offers and had a higher proportion of respondents who could not distinguish between “Use by” and “Best before” dates than those in the affluent and middle- income suburbs. The reasons to food waste generation overlap between the towns. However, between the suburbs, the respondents from households in the affluent suburbs pointed that they were mainly generating and disposing food waste because they did not think it is an issue. Excessive cooking and food expiring before being consumed were found to be the most common reasons for food waste generation and disposal among households in the low and middle-income suburbs. The times which households are likely to generate more food waste were investigated. Nonetheless, only a few households indicated that there were times that they generated and disposed more food in the bins. The most cited times in the affluent suburbs were during Christmas (54%) and in summer (41%). Festive season (65%) and traditional ceremonies (37%) were the most cited times in the middle-income suburbs, while festive season (46%) and the summer season (36%) were the most cites among households in the low- income suburbs. The dimensions of shopping and household food waste behaviour is reflected in the types and quantities of food waste generated. The results reveal that vegetables were the most wasted food type in Cradock (26%) and in Middelburg (30%), while tinned food and dairy were the least discarded food types in both study towns with no significant differences in proportions of households discarding all six food types. One of the key results is that the average self-reported and weighed food waste generated per capita per annum for the two towns was 23.40±47.20 and 202.60±128.30 kg/capita/year, respectively as compared to the estimated 6-11 kg per annum in sub-Saharan Africa and South and Southeast Asia. Between the towns, Cradock generated more food waste (5.05±2.68 kg) than those in Middleburg (3.84±2.59 kg) in the previous 48 hours. It was also evident that each household and each person in Cradock generated more food waste at breakfast and the least at lunch, while in Middelburg the highest average amount of food waste generated was observed at supper and the least at lunch. The results indicate that household size and employment status were negatively correlated to food waste generation, while wealth status and gender were positively correlated to food waste generation. Majority of households (74% in Cradock and 73% in Middelburg) had no household food waste minimisation strategies implemented. The most cited strategies in place were cooking less frequently, cooking small portions and chopping and freezing vegetables as an anti-food waste strategy. Worth noting is that the small proportion of households with strategies in place are faced with a challenge of some household members showing unwillingness to effectively implement the strategies. The results also reveal that children wasted more food than adults, particularly girls. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mtakati, Sinako
- Date: 2022-04
- Subjects: Food waste South Africa Cradock , Food waste South Africa Middelburg (Eastern Cape) , Sanitary landfills Environmental aspects South Africa , Greenhouse gases Environmental aspects South Africa , Income distribution South Africa , Socio-economic status South Africa , Waste minimization South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232159 , vital:49967
- Description: Food waste is becoming an important issue considering greenhouse gas emissions from landfills. However, data on the quantities of food disposed remains limited, especially for developing, countries including South Africa. Global food waste estimates suggest that households in developed countries waste more food than those in developing countries. Further, research shows that lack of food waste management impacts negatively on the global efforts to combat food waste generation. I therefore set out to present primary data relating to household food waste generation and minimisation within a South African context. The case study covers two towns in the Eastern Cape province, namely Cradock and Middelburg, with a combined population of 55 352 people. Household food waste assessment and quantification was undertaken using two methods, 1) questionnaires to explore quantities of different types of food wasted by households, and 2) kitchen scales to measure the amounts of food discarded by households. Participating households in each suburb were selected randomly. Differences in shopping and household food waste behaviour in households from different income suburbs is vital to understand as it sets an effective approach to food waste interventions that might have a positive impact in minimising food waste generation. In this thesis, differences in shopping and household food waste behaviour across households in the affluent, middle and low-income suburbs is uncovered. A questionnaire was conducted and households in the affluent suburbs purchased food more frequently and had the highest percentage of respondents that used shopping list when buying food than those in the middle and low-income suburbs. The thesis also indicates that households in the low-income suburbs were more attracted to food special offers and had a higher proportion of respondents who could not distinguish between “Use by” and “Best before” dates than those in the affluent and middle- income suburbs. The reasons to food waste generation overlap between the towns. However, between the suburbs, the respondents from households in the affluent suburbs pointed that they were mainly generating and disposing food waste because they did not think it is an issue. Excessive cooking and food expiring before being consumed were found to be the most common reasons for food waste generation and disposal among households in the low and middle-income suburbs. The times which households are likely to generate more food waste were investigated. Nonetheless, only a few households indicated that there were times that they generated and disposed more food in the bins. The most cited times in the affluent suburbs were during Christmas (54%) and in summer (41%). Festive season (65%) and traditional ceremonies (37%) were the most cited times in the middle-income suburbs, while festive season (46%) and the summer season (36%) were the most cites among households in the low- income suburbs. The dimensions of shopping and household food waste behaviour is reflected in the types and quantities of food waste generated. The results reveal that vegetables were the most wasted food type in Cradock (26%) and in Middelburg (30%), while tinned food and dairy were the least discarded food types in both study towns with no significant differences in proportions of households discarding all six food types. One of the key results is that the average self-reported and weighed food waste generated per capita per annum for the two towns was 23.40±47.20 and 202.60±128.30 kg/capita/year, respectively as compared to the estimated 6-11 kg per annum in sub-Saharan Africa and South and Southeast Asia. Between the towns, Cradock generated more food waste (5.05±2.68 kg) than those in Middleburg (3.84±2.59 kg) in the previous 48 hours. It was also evident that each household and each person in Cradock generated more food waste at breakfast and the least at lunch, while in Middelburg the highest average amount of food waste generated was observed at supper and the least at lunch. The results indicate that household size and employment status were negatively correlated to food waste generation, while wealth status and gender were positively correlated to food waste generation. Majority of households (74% in Cradock and 73% in Middelburg) had no household food waste minimisation strategies implemented. The most cited strategies in place were cooking less frequently, cooking small portions and chopping and freezing vegetables as an anti-food waste strategy. Worth noting is that the small proportion of households with strategies in place are faced with a challenge of some household members showing unwillingness to effectively implement the strategies. The results also reveal that children wasted more food than adults, particularly girls. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04
Hydraulic vulnerability of Subtropical Thicket to drought : a remote sensing and physiological perspective
- Authors: Buttner, Daniel Harry
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55455 , vital:52017
- Description: Water availability is one of largest constraints on plant survival, growth, and species distribution globally. The recent escalation in tree mortality coupled with declining precipitation and amplified temperatures has implicated drought as a major cause behind many large-scale dieback events observed across the world. Raising the question, what makes some species more resistant and persist while others dwindle and vanish from the landscape? The observed variability in species drought susceptibility demonstrates the complexity of physiological responses of plants to changes in water availability. Hydraulic dysfunction in plants has been purported to be the key mechanism behind drought-induced mortality provoking interest in hydraulic traits and critical thresholds of xylem physiological function. The capability of species to maintain hydraulic functionality under drought strongly influences the survival and general productivity towards water deficits. Hence, two core objectives, and subsequently aims, of this thesis are firstly to investigate the effect of drought on Subtropical Thicket vegetation health and productivity, and secondly to examine the underpinning physiological mechanisms and functional thresholds relaying speciesspecific drought vulnerability within this semi-arid biome. In first data chapter, this thesis offers an assessment of vegetation change under drought and its influence on plant physiological function and productivity across a subsection of Subtropical Thicket distribution. Additionally, this chapter provides a regional scale perspective of drought on Subtropical Thicket flora in the Eastern Cape of South Africa. A severe anomalous dieback event, which coincided with extreme, accumulative drought conditions was observed in 2020. Employing a combination of field-based approaches and remote sensing, this chapter aimed to provide a comprehensive report of the extent and severity of crown defoliation and canopy dieback following this event, additionally describing predisposing and compounding factors. Based on Standardized Precipitation Evapotranspiration and Standardized Precipitation Indices this event began in 2015 and coincided with amplified temperatures, exacerbating evaporative demand. Aerial UAV surveys and field-based investigations were undertaken. Remotely sensed (RS) indices provided an avenue for extensive spatiotemporal investigations to uncover the extent of drought-related impact on vegetation productivity and discuss potential underpinning mechanisms behind drought-induced mortality in Subtropical Thicket. Leveraging long-term time series RS data, Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), from Moderate Resolution Imaging Spectroradiometer (MODIS) satellites as a proxy vegetation physiological status in combination with SPI and SPEI describing drought condition and groundbased surveying defining canopy vitality condition this study incidentally addressed the aim of endeavoring to link drought-induced mortality and early warning symptoms observed in the field with RS time series data to describe drought impacts across Subtropical Thicket. Furthermore, the findings of this chapter demonstrate the spatial and temporal heterogeneity in drought impacts on Subtropical Thicket. The recent drought of 2015 till 2021 is the longest documented period for the past 50 years in which there has been no accumulated net positive water availability, this apparently perpetual state of water deficiency has enacted a high cost for vegetation productivity and growth for the study area, exhibited well by average NDVI values of less than -0.5 for over 70% of the research site. The findings of this chapter report, to the contrary of anecdotal suggestions in the literature, on the intrinsic tolerance of Subtropical Thicket and that ii drought has a far more significant role on overall vegetation productivity, growth, and mortality in this region. The second data chapter assess whole-plant physiological functionality during a drought event in the Eastern Cape, South Africa. This is the first study in Subtropical Thicket to quantify in situ hydraulic functional integrity under a natural drought event testing the leading hypothesis describing tree mortality – hydraulic dysfunction. This chapter firstly, investigates hydraulic traits (e.g., turgor loss point) and describe key physiological thresholds (e.g., P50) for maintaining function during drought. Secondly, levels of native embolism were determined under drought conditions and combined with measurements of xylem vulnerability to embolism providing an estimation of degree of hydraulic dysfunction experienced by six dominant woody canopy species in Subtropical Thicket – to quantify interspecific drought tolerance and susceptibility. Subtropical Thicket species exhibited remarkable tolerance towards desiccation (TLP from as low as -3MPa) and hydraulic functional resistance to embolism (P50 value as low as -7.89MPa). The observed unexpected drought resilience of subtropical derived lineages highlights the intrinsic evolutionary role aridification had, selecting for greater embolism resistance and community-level conservatism in drought resistance of Subtropical Thicket. The level of native embolism and hydraulic safety margins identified two species (Schotia latifolia and Polyagla myrtifolia) that were the most vulnerable, and a third (Pappea capensis) moderately vulnerable, then the remaining studied species – this could result in community-level adjustments in species composition and structure under future projected climate change scenarios where, increased frequencies of drought events are anticipated. This retrospective assessment of canopy vigor with physiological functional thresholds evokes hydraulic dysfunction as the principal mechanism of observed Subtropical Thicket dieback to drought. This chapter provides crucial in situ data for predictive assertions around drought-induced mortality risk in a phylogenetically diverse and climatically unique biome of southern Africa; and is the first to identify critical hydraulic thresholds for tree species within this region. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Buttner, Daniel Harry
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55455 , vital:52017
- Description: Water availability is one of largest constraints on plant survival, growth, and species distribution globally. The recent escalation in tree mortality coupled with declining precipitation and amplified temperatures has implicated drought as a major cause behind many large-scale dieback events observed across the world. Raising the question, what makes some species more resistant and persist while others dwindle and vanish from the landscape? The observed variability in species drought susceptibility demonstrates the complexity of physiological responses of plants to changes in water availability. Hydraulic dysfunction in plants has been purported to be the key mechanism behind drought-induced mortality provoking interest in hydraulic traits and critical thresholds of xylem physiological function. The capability of species to maintain hydraulic functionality under drought strongly influences the survival and general productivity towards water deficits. Hence, two core objectives, and subsequently aims, of this thesis are firstly to investigate the effect of drought on Subtropical Thicket vegetation health and productivity, and secondly to examine the underpinning physiological mechanisms and functional thresholds relaying speciesspecific drought vulnerability within this semi-arid biome. In first data chapter, this thesis offers an assessment of vegetation change under drought and its influence on plant physiological function and productivity across a subsection of Subtropical Thicket distribution. Additionally, this chapter provides a regional scale perspective of drought on Subtropical Thicket flora in the Eastern Cape of South Africa. A severe anomalous dieback event, which coincided with extreme, accumulative drought conditions was observed in 2020. Employing a combination of field-based approaches and remote sensing, this chapter aimed to provide a comprehensive report of the extent and severity of crown defoliation and canopy dieback following this event, additionally describing predisposing and compounding factors. Based on Standardized Precipitation Evapotranspiration and Standardized Precipitation Indices this event began in 2015 and coincided with amplified temperatures, exacerbating evaporative demand. Aerial UAV surveys and field-based investigations were undertaken. Remotely sensed (RS) indices provided an avenue for extensive spatiotemporal investigations to uncover the extent of drought-related impact on vegetation productivity and discuss potential underpinning mechanisms behind drought-induced mortality in Subtropical Thicket. Leveraging long-term time series RS data, Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), from Moderate Resolution Imaging Spectroradiometer (MODIS) satellites as a proxy vegetation physiological status in combination with SPI and SPEI describing drought condition and groundbased surveying defining canopy vitality condition this study incidentally addressed the aim of endeavoring to link drought-induced mortality and early warning symptoms observed in the field with RS time series data to describe drought impacts across Subtropical Thicket. Furthermore, the findings of this chapter demonstrate the spatial and temporal heterogeneity in drought impacts on Subtropical Thicket. The recent drought of 2015 till 2021 is the longest documented period for the past 50 years in which there has been no accumulated net positive water availability, this apparently perpetual state of water deficiency has enacted a high cost for vegetation productivity and growth for the study area, exhibited well by average NDVI values of less than -0.5 for over 70% of the research site. The findings of this chapter report, to the contrary of anecdotal suggestions in the literature, on the intrinsic tolerance of Subtropical Thicket and that ii drought has a far more significant role on overall vegetation productivity, growth, and mortality in this region. The second data chapter assess whole-plant physiological functionality during a drought event in the Eastern Cape, South Africa. This is the first study in Subtropical Thicket to quantify in situ hydraulic functional integrity under a natural drought event testing the leading hypothesis describing tree mortality – hydraulic dysfunction. This chapter firstly, investigates hydraulic traits (e.g., turgor loss point) and describe key physiological thresholds (e.g., P50) for maintaining function during drought. Secondly, levels of native embolism were determined under drought conditions and combined with measurements of xylem vulnerability to embolism providing an estimation of degree of hydraulic dysfunction experienced by six dominant woody canopy species in Subtropical Thicket – to quantify interspecific drought tolerance and susceptibility. Subtropical Thicket species exhibited remarkable tolerance towards desiccation (TLP from as low as -3MPa) and hydraulic functional resistance to embolism (P50 value as low as -7.89MPa). The observed unexpected drought resilience of subtropical derived lineages highlights the intrinsic evolutionary role aridification had, selecting for greater embolism resistance and community-level conservatism in drought resistance of Subtropical Thicket. The level of native embolism and hydraulic safety margins identified two species (Schotia latifolia and Polyagla myrtifolia) that were the most vulnerable, and a third (Pappea capensis) moderately vulnerable, then the remaining studied species – this could result in community-level adjustments in species composition and structure under future projected climate change scenarios where, increased frequencies of drought events are anticipated. This retrospective assessment of canopy vigor with physiological functional thresholds evokes hydraulic dysfunction as the principal mechanism of observed Subtropical Thicket dieback to drought. This chapter provides crucial in situ data for predictive assertions around drought-induced mortality risk in a phylogenetically diverse and climatically unique biome of southern Africa; and is the first to identify critical hydraulic thresholds for tree species within this region. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
I want him to hold me, but I’m afraid to ask: the objective correlative and the souvenir as representational narrative devices of queer male intimacy
- Authors: Ferreira, Evaan Jason
- Date: 2022-04
- Subjects: Sexual minorities in art , Sexual minority culture , Intimacy (Psychology) , Sexual minorities in motion pictures , Intimacy (Psychology) in motion pictures , Homosexuality and motion pictures , Motion pictures Study and teaching , New media art , Nostalgia , Souvenirs (Keepsakes) , Gay men , Queer male intimacy , Objective correlative
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232556 , vital:50002
- Description: This thesis centres itself around an investigation into the representations of the relationship between intimacies and ideas of romance, love, desire, and vulnerability in male relationships. The premise for this body of work was sparked by my own observations on the conflation of sex and intimacy in representations of queer male love—particularly (but not exclusively) in mainstream film and media. Whilst intimacy and sex are not unrelated, the over-emphasis on the physical when trying to represent the connection between two men led me to consider other ways in which a relationship or special connection could be gestured towards — through other kinds of signifiers that last longer than physical contact and point to the importance of a particular connection. In the introduction, I consider my own experiences as a closeted queer teen when contemplating representations of queer relationships in mainstream media. I explore several studies by gender and film theorists who consider reasons and modes in which the representations of queer intimacies on-screen are distorted to favour a presumed heterosexual audience. In the first chapter, I discuss two potential means by which to relay a more complex emotional state via the use of narrative signifiers. I examine T.S. Eliot's (1919) theory on the objective correlative in narratives as a means to explore the emotional state of a character through metaphors which open up the reading rather than illustrating it through dialogue or direct speech. I then explore Susan Stewart's (1992) ideas on souvenirs of personal experience. In Chapter Two, I conduct a close reading of three mainstream films, which employ such signifiers in the attempt to share more complex representations of queer male intimacies through well-developed storylines and characters. The films Brokeback Mountain (2006), Moonlight (2016), and Call Me by Your Name (2017) have been selected based on their use of the objective correlative and souvenirs as plot devices (rather than exclusively physical intimacy) to demonstrate the emotional resonance between characters. The third and final chapter explores my own use of objective correlatives and souvenirs as symbolic, narrative devices in my practical body of work: an online garden of remembrance. My practical work focuses largely on the process of creation of these intimacy objects (the objective correlative or the souvenir) through an investigation into my own poetry, which details my experiences of intimacies with other men, specifically where vulnerability and secrecy played a large role. , Thesis (MFA) -- Faculty of Humanities, Fine Arts, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ferreira, Evaan Jason
- Date: 2022-04
- Subjects: Sexual minorities in art , Sexual minority culture , Intimacy (Psychology) , Sexual minorities in motion pictures , Intimacy (Psychology) in motion pictures , Homosexuality and motion pictures , Motion pictures Study and teaching , New media art , Nostalgia , Souvenirs (Keepsakes) , Gay men , Queer male intimacy , Objective correlative
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232556 , vital:50002
- Description: This thesis centres itself around an investigation into the representations of the relationship between intimacies and ideas of romance, love, desire, and vulnerability in male relationships. The premise for this body of work was sparked by my own observations on the conflation of sex and intimacy in representations of queer male love—particularly (but not exclusively) in mainstream film and media. Whilst intimacy and sex are not unrelated, the over-emphasis on the physical when trying to represent the connection between two men led me to consider other ways in which a relationship or special connection could be gestured towards — through other kinds of signifiers that last longer than physical contact and point to the importance of a particular connection. In the introduction, I consider my own experiences as a closeted queer teen when contemplating representations of queer relationships in mainstream media. I explore several studies by gender and film theorists who consider reasons and modes in which the representations of queer intimacies on-screen are distorted to favour a presumed heterosexual audience. In the first chapter, I discuss two potential means by which to relay a more complex emotional state via the use of narrative signifiers. I examine T.S. Eliot's (1919) theory on the objective correlative in narratives as a means to explore the emotional state of a character through metaphors which open up the reading rather than illustrating it through dialogue or direct speech. I then explore Susan Stewart's (1992) ideas on souvenirs of personal experience. In Chapter Two, I conduct a close reading of three mainstream films, which employ such signifiers in the attempt to share more complex representations of queer male intimacies through well-developed storylines and characters. The films Brokeback Mountain (2006), Moonlight (2016), and Call Me by Your Name (2017) have been selected based on their use of the objective correlative and souvenirs as plot devices (rather than exclusively physical intimacy) to demonstrate the emotional resonance between characters. The third and final chapter explores my own use of objective correlatives and souvenirs as symbolic, narrative devices in my practical body of work: an online garden of remembrance. My practical work focuses largely on the process of creation of these intimacy objects (the objective correlative or the souvenir) through an investigation into my own poetry, which details my experiences of intimacies with other men, specifically where vulnerability and secrecy played a large role. , Thesis (MFA) -- Faculty of Humanities, Fine Arts, 2022
- Full Text:
- Date Issued: 2022-04
Ifuthe leelwimi kwimpumelelo yabafundi bebanga leshumi elinambini kwizifundo zejiyografi(sezelizwe) kwizikolo ezibini ezichongiweyo kwisithili saseMonti
- Authors: Gcaki, Nomnqakati
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55342 , vital:51915
- Description: Isahluko sokuqala sixoxa ngengxaki yophando esi siseko kolu phando, nemibuzo yophando kunye neenjongo zokuba isifundo esikhoyo sifuna ukufezekisa ntoni. Ngokunxulumene nengxaki ephandwayo, esi sahluko sigxile kuphononongo loncwadi ukuze kuhlolwe ubudlelwane phakathi kolwimi lokufundisa kunye nempumelelo yabafundi kwiBanga le-12 kwisifundo seJiyografi. Ukuhlolwa koncwadi kuthathwe kwimigaqo-nkqubo yokufundisa kunye neethiyori zophuhliso lokuqonda nenkcubeko. Inkqubo yeethiyori ezikhethiweyo zisetyenziselwa ukwenza ingqiqo yokuba ulwimi lokufundisa luba nefuthe njani ekufundiseni nasekukhuleni kwengqondo nokuqiqa komfundi. Ngophononongo loncwadi, umphandi unqwenela ukufumanisa ubunzima abahlangabezana nabo abafundi ekufundeni iJiyografi ngolwimi lwesiNgesi kwiBanga leshumi elinesibini. Olu phando luza kuphonononga nzulu ifuthe leelwimi kwimpumelelo yabafundi kwisifundo seJiyografi kubafundi besigaba seshumi elinambini kujoliswe kwindlela abaphumelela ngayo kwiimviwo zokuphela konyaka.Olu phando luza kujongwa kwizikolo ezibini kwiphondo leMpuma Koloni kwisithili saseMonti phakathi kweminyaka wama-2016 ukuya kuma-2018.Ngokophando esele lwenziwe, abafundi abalwimi lwabo lwasekhaya lusisiXhosa kufanele ukuba bafundiswa ngolwimi lwabo abazikhethele lona ukutsho oko isiXhosa kwaye bavavanywe kwangalo. Oku akunjalo njengoko amaphepha abo ovavanyo engolwimi lwesiNgesi, lwimi olo olufika lubabeke phantsi konxinzelelo olukhulu olubenza bangabinakho ukuzithemba nokuziva bekhululekile xa bephendula imibuzo emagumbini okufundela. Umphandi olu luvo uluseka ngengxelo ayifumene kumaxwebhu eSebe lezeMfundo (2018 NSC Chief Markers Report) yesifundo seJiyografi iphepha lokuqala. , Thesis (MA) -- Faculty of Humanities, School of Language, Media and Communication, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Gcaki, Nomnqakati
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55342 , vital:51915
- Description: Isahluko sokuqala sixoxa ngengxaki yophando esi siseko kolu phando, nemibuzo yophando kunye neenjongo zokuba isifundo esikhoyo sifuna ukufezekisa ntoni. Ngokunxulumene nengxaki ephandwayo, esi sahluko sigxile kuphononongo loncwadi ukuze kuhlolwe ubudlelwane phakathi kolwimi lokufundisa kunye nempumelelo yabafundi kwiBanga le-12 kwisifundo seJiyografi. Ukuhlolwa koncwadi kuthathwe kwimigaqo-nkqubo yokufundisa kunye neethiyori zophuhliso lokuqonda nenkcubeko. Inkqubo yeethiyori ezikhethiweyo zisetyenziselwa ukwenza ingqiqo yokuba ulwimi lokufundisa luba nefuthe njani ekufundiseni nasekukhuleni kwengqondo nokuqiqa komfundi. Ngophononongo loncwadi, umphandi unqwenela ukufumanisa ubunzima abahlangabezana nabo abafundi ekufundeni iJiyografi ngolwimi lwesiNgesi kwiBanga leshumi elinesibini. Olu phando luza kuphonononga nzulu ifuthe leelwimi kwimpumelelo yabafundi kwisifundo seJiyografi kubafundi besigaba seshumi elinambini kujoliswe kwindlela abaphumelela ngayo kwiimviwo zokuphela konyaka.Olu phando luza kujongwa kwizikolo ezibini kwiphondo leMpuma Koloni kwisithili saseMonti phakathi kweminyaka wama-2016 ukuya kuma-2018.Ngokophando esele lwenziwe, abafundi abalwimi lwabo lwasekhaya lusisiXhosa kufanele ukuba bafundiswa ngolwimi lwabo abazikhethele lona ukutsho oko isiXhosa kwaye bavavanywe kwangalo. Oku akunjalo njengoko amaphepha abo ovavanyo engolwimi lwesiNgesi, lwimi olo olufika lubabeke phantsi konxinzelelo olukhulu olubenza bangabinakho ukuzithemba nokuziva bekhululekile xa bephendula imibuzo emagumbini okufundela. Umphandi olu luvo uluseka ngengxelo ayifumene kumaxwebhu eSebe lezeMfundo (2018 NSC Chief Markers Report) yesifundo seJiyografi iphepha lokuqala. , Thesis (MA) -- Faculty of Humanities, School of Language, Media and Communication, 2022
- Full Text:
- Date Issued: 2022-04
Illicit economic activities of irregular warfare groups: A case study of the Islamic state (is) and the response of the international community
- Authors: Mdhluli, Kurisani Dankie
- Date: 2022-04
- Subjects: Petroleum industry and trade --Political aspects , Terrorism , Middle East --Foreign relations
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55269 , vital:51433
- Description: This study is about the illicit economic activities (especially oil smuggling) of the Islamic State (IS) and the response of the international community (UNSC, national governments, and nonstate actors) from 2014 until 2021. The context of the study is the ongoing Syrian civil war and the IS Caliphate, in Syria and Iraq. Through Critical Terrorism Studies (CTS) as a critical approach to terrorism studies the study investigates the contribution of oil smuggling to the military strength of the IS. The study evaluates the effectuality of the force-based counterterrorism strategies deployed by the international community against the IS. Ultimately, the study develops a CTS-oriented approach to understanding how actions can be taken to counteract similar global terror threats in the future. The IS is a global Salafi Islamic irregular warfare group that originates from the Middle East. In June 2014, the IS proclaimed a Caliphate (Islamic state) in the Middle East, only for it to be dismantled by the US-led coalition forces and local Kurdish forces in 2019. The study applies qualitative documentary research. It utilises both primary and secondary sources. The research findings reveal that oil smuggling was a significant source of income for the IS only for a short period of time (early 2014 till late 2015). However, few other economic activities of the IS were consistent in generating income throughout. Furthermore, no evidence suggests that illicit oil trade profits of the IS were used to strengthen the military capacity of the organization. Instead, data revealed that the IS relied heavily on military weapons seized from its opponents on the battlefield including weapons from the US that were meant for the local Kurdish forces. The findings further reveal that while military force (mainly airstrikes) by the international community significantly reduced IS’s oil production and smuggling activities, they at the same time also exacerbated social challenges such as the refugee crisis, damage to infrastructure and loss of innocent civilian lives. , Thesis (MA) -- Faculty of Humanities, History and Political Studies , 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mdhluli, Kurisani Dankie
- Date: 2022-04
- Subjects: Petroleum industry and trade --Political aspects , Terrorism , Middle East --Foreign relations
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55269 , vital:51433
- Description: This study is about the illicit economic activities (especially oil smuggling) of the Islamic State (IS) and the response of the international community (UNSC, national governments, and nonstate actors) from 2014 until 2021. The context of the study is the ongoing Syrian civil war and the IS Caliphate, in Syria and Iraq. Through Critical Terrorism Studies (CTS) as a critical approach to terrorism studies the study investigates the contribution of oil smuggling to the military strength of the IS. The study evaluates the effectuality of the force-based counterterrorism strategies deployed by the international community against the IS. Ultimately, the study develops a CTS-oriented approach to understanding how actions can be taken to counteract similar global terror threats in the future. The IS is a global Salafi Islamic irregular warfare group that originates from the Middle East. In June 2014, the IS proclaimed a Caliphate (Islamic state) in the Middle East, only for it to be dismantled by the US-led coalition forces and local Kurdish forces in 2019. The study applies qualitative documentary research. It utilises both primary and secondary sources. The research findings reveal that oil smuggling was a significant source of income for the IS only for a short period of time (early 2014 till late 2015). However, few other economic activities of the IS were consistent in generating income throughout. Furthermore, no evidence suggests that illicit oil trade profits of the IS were used to strengthen the military capacity of the organization. Instead, data revealed that the IS relied heavily on military weapons seized from its opponents on the battlefield including weapons from the US that were meant for the local Kurdish forces. The findings further reveal that while military force (mainly airstrikes) by the international community significantly reduced IS’s oil production and smuggling activities, they at the same time also exacerbated social challenges such as the refugee crisis, damage to infrastructure and loss of innocent civilian lives. , Thesis (MA) -- Faculty of Humanities, History and Political Studies , 2022
- Full Text:
- Date Issued: 2022-04
Impacts of algal blooms in a temperate Estuarine fish nursery area, South Africa
- Authors: Bornman, Eugin
- Date: 2022-04
- Subjects: Cyanobacterial toxins --Environmental aspects , Estuarine eutrophication --South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55899 , vital:54398
- Description: Anthropogenically-derived eutrophication and Harmful Algal Blooms (HABs) are an increasing threat to estuarine ecosystems globally. The rapid population growth in coastal areas and the mismanagement of water resources have led to the rapid increase in eutrophication in estuaries. Consequently, HABs have become frequent phenomena with severe impacts on the ecological functioning of these systems. A paucity exists in understanding the specific mechanisms of how HABs impact estuarine communities globally. This has not been studied in South Africa, despite the observed increase in the occurrence of HABs in the past few decades. Therefore, this study investigated the impact of HABs on the ecological functioning of the anthropogenically altered Sundays Estuary, South Africa, which is affected by predictable and recurrent HABs of the raphidophyte, Heterosigma akashiwo. This study found that a high density (> 1000 cell m L-1 ) of H. akashiwo was present during all but the winter months in the poly- to mesohaline zone, yet it peaked in warmer spring/summer months with a density of ca. 70 000 cell m L-1 corresponding to 800 µg Chl-a L -1 . This species significantly altered the estuary's water quality, causing supersaturated surface- and hypoxic bottom-water during severe HABs or referred to as hypereutrophic bloom phases (> 60 µg Chl-a L -1 ). Despite these changes, the common copepod, Pseudodiaptomus hessei, occurred at similar densities among HAB phases and responded to similar triggers to the HAB. However, a shift in predator-prey interactions within the zooplankton community was evident, with scavenger or opportunist species such as the isopod, Cirolana fluviatilis, and the polychaete, Perinereis falsovariegata, occurring at higher densities during hypereutrophic bloom phases. The overall abundance of juvenile and small adult fishes were high during HABs, but the diversity decreased during HABs. Some species, notably the Mugilidae occurred at lower densities during HABs. Mugilidae also had pronounced histological gill alterations and a lowered proportion of secondary lamellae available for gas exchange during an in situ cage experiment where fishes were isolated inside and outside the HAB. Deformities such as tumorous growths were also found for the first time in a South African Estuary. This indicated a stressed population of Mugilidae in the Sundays Estuary. The ubiquitous mugilid, Mugil cephalus, actively avoided HABs during an acoustic telemetry study, despite having a home range that overlapped the HAB area. Tagged individuals mostly occupied areas directly above the HAB in the upper mesohaline to lower oligohaline zones and only iv briefly transitioned through the HAB area to utilise the lower reaches of the estuary. Since the formation of HABs is reliant on various factors, including specific species responses, environmental variables, nutrient enrichment, and flow characteristics, the impacts of HABs on estuarine communities may vary between estuarine systems or affected species. Therefore, more research that focuses on the impacts of HABs on estuaries is needed to limit the potential loss of ecosystem services. Particularly in light of further unsustainable development, upstream freshwater abstraction and climate change, will cause more frequent and severe HABs, that may result in fish population declines in the long-term. Better management and mitigation strategies are needed to reduce HAB formation such as reducing nutrient enrichment and restoring natural freshwater flow and flooding events to the Sundays Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Bornman, Eugin
- Date: 2022-04
- Subjects: Cyanobacterial toxins --Environmental aspects , Estuarine eutrophication --South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55899 , vital:54398
- Description: Anthropogenically-derived eutrophication and Harmful Algal Blooms (HABs) are an increasing threat to estuarine ecosystems globally. The rapid population growth in coastal areas and the mismanagement of water resources have led to the rapid increase in eutrophication in estuaries. Consequently, HABs have become frequent phenomena with severe impacts on the ecological functioning of these systems. A paucity exists in understanding the specific mechanisms of how HABs impact estuarine communities globally. This has not been studied in South Africa, despite the observed increase in the occurrence of HABs in the past few decades. Therefore, this study investigated the impact of HABs on the ecological functioning of the anthropogenically altered Sundays Estuary, South Africa, which is affected by predictable and recurrent HABs of the raphidophyte, Heterosigma akashiwo. This study found that a high density (> 1000 cell m L-1 ) of H. akashiwo was present during all but the winter months in the poly- to mesohaline zone, yet it peaked in warmer spring/summer months with a density of ca. 70 000 cell m L-1 corresponding to 800 µg Chl-a L -1 . This species significantly altered the estuary's water quality, causing supersaturated surface- and hypoxic bottom-water during severe HABs or referred to as hypereutrophic bloom phases (> 60 µg Chl-a L -1 ). Despite these changes, the common copepod, Pseudodiaptomus hessei, occurred at similar densities among HAB phases and responded to similar triggers to the HAB. However, a shift in predator-prey interactions within the zooplankton community was evident, with scavenger or opportunist species such as the isopod, Cirolana fluviatilis, and the polychaete, Perinereis falsovariegata, occurring at higher densities during hypereutrophic bloom phases. The overall abundance of juvenile and small adult fishes were high during HABs, but the diversity decreased during HABs. Some species, notably the Mugilidae occurred at lower densities during HABs. Mugilidae also had pronounced histological gill alterations and a lowered proportion of secondary lamellae available for gas exchange during an in situ cage experiment where fishes were isolated inside and outside the HAB. Deformities such as tumorous growths were also found for the first time in a South African Estuary. This indicated a stressed population of Mugilidae in the Sundays Estuary. The ubiquitous mugilid, Mugil cephalus, actively avoided HABs during an acoustic telemetry study, despite having a home range that overlapped the HAB area. Tagged individuals mostly occupied areas directly above the HAB in the upper mesohaline to lower oligohaline zones and only iv briefly transitioned through the HAB area to utilise the lower reaches of the estuary. Since the formation of HABs is reliant on various factors, including specific species responses, environmental variables, nutrient enrichment, and flow characteristics, the impacts of HABs on estuarine communities may vary between estuarine systems or affected species. Therefore, more research that focuses on the impacts of HABs on estuaries is needed to limit the potential loss of ecosystem services. Particularly in light of further unsustainable development, upstream freshwater abstraction and climate change, will cause more frequent and severe HABs, that may result in fish population declines in the long-term. Better management and mitigation strategies are needed to reduce HAB formation such as reducing nutrient enrichment and restoring natural freshwater flow and flooding events to the Sundays Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
In vitro pharmacological screening of thiazolidinedione-derivatives on diabetes and Alzheimer’s potential therapeutic targets
- Authors: Arineitwe, Charles
- Date: 2022-04
- Subjects: Diabetes Treatment , Alzheimer's disease Treatment , Antioxidants Therapeutic use , Rosiglitazone , Hypoglycemic agents , In vitro screening , Thiazolidinedione Derivatives
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232171 , vital:49968
- Description: There is an increased prevalence of diabetes and other non-communicable diseases in Sub-Saharan Africa and globally. In South Africa, the prevalence of type 2 Diabetes mellitus is currently estimated at 9.0% in people aged 30 and older and is expected to increase. Diabetes-related complications result in acute alterations in the mental state due to poor metabolic control as well as greater rates of decline in cognitive functioning with age, higher prevalence of depression and increased risk of Alzheimer’s disease. Alzheimer’s disease is the most common form of dementia in older adults and possibly contributes to 60 - 70% of cases. Alzheimer’s disease remains incurable, its progression inevitable with the currently available symptomatic therapies being palliative while the treatment of diabetes relies on insulin preparations and other glucose-lowering agents. Current treatment options have numerous side effects such as hypoglycaemia, diarrhoea, weight gain and abnormal liver function. This has geared the investigation of new generations of small molecules which exhibit improved efficacy and safety profiles. On this basis, several studies have shown that thiazolidinediones and their corresponding derivatives exhibit a broad spectrum of biological activities including anti-inflammatory, and antioxidant activities. Furthermore, recent evidence from experimental, epidemiological, and clinical studies highlight the utility of antioxidants for treating diabetes and its complications. Interestingly, there is increasing evidence that links diabetes and Alzheimer’s disease due to their pathophysiology and suppressing glycaemia has been shown to be beneficial in Alzheimer’s disease treatment. Accordingly, the aim of this study, was to evaluate the anti-diabetic and anti-Alzheimer’s properties of four novel synthesized thiazolidinedione-derivatives owing to their antioxidant properties. Methods The aim of this study was achieved through performing ferric reducing antioxidant power activity, 2,2’-Diphenyl-1-Picry Hydrazyl radical scavenging activity, α-amylase inhibition, α-glucosidase inhibition, aldose reductase inhibition, protein tyrosine phosphatase-1B inhibition, dipeptidyl peptidase-4 inhibition, acetylcholinesterase inhibition, matrix metalloproteinase-1 inhibition, and β-amyloid aggregation inhibition assays. In addition, peroxisome proliferator-activated receptor-γ activation was performed through docking studies. To establish physicochemical properties of TZD derivatives investigated, further in-silico studies were done using SwissADME tools. Results To this end, in-vitro and in-silico studies were successfully performed. In-silico ADME profiling predicted these derivatives to be drug-like with moderate to good solubility in the GI and not blood-brain barrier permeable. Furthermore, docking of these molecules against PPARγ predicted a similar mode of action to that of thiazolidinediones using Rosiglitazone as the standard drug with TZDD2 and TZDD4 forming equivalent conformations to that of Rosiglitazone in the same binding site and TZDD3 having an equivalent LBE to that of Rosiglitazone (-8.84 and -8.63kcal/mol respectively). In-vitro evaluation predicted a moderate antioxidant activity with TZDD2 and 3 exhibiting the highest FRAP activity and DPPH radical scavenging activity. Furthermore, enzymatic inhibition assays showed a relative inhibition activity with TZDD3 exhibited > 100% inhibition in concentrations ≥ 30 μg/mL and TZDD1, 2 and 4 exhibited ≥ 50% inhibition activity in all the concentrations (10, 20, 30, 40 and 50 μg/mL) in the α-amylase inhibition assay. Similarly, in the α-glucosidase inhibition assay, all the four derivatives exhibited a concentration dependent activity with TZDD3 showing the most activity. All the four derivatives exhibited ≥ 30% inhibition in the aldose reductase inhibition assay except TZDD1 at 10 μg/mL. TZDD4 exhibited a concentration dependent inhibition activity in the protein tyrosine phosphatase-1B inhibition assay. Interestingly, TZDD3 showed a decreasing inhibition activity as its concentration increased from 10 μg/mL through to 50 μg/mL. In the dipeptidyl peptidase–4 inhibition assay, TZDD2 and TZDD4 exhibited ≥ 20% inhibition activity across all the concentrations and in the acetylcholinesterase assay, TZDD1, 3 and 4 exhibited ≥ 25% across all the concentrations. Interestingly, in the matrix metalloproteinase-1 inhibition assay, some of these derivatives exhibited partial activation activity and partial inhibition with TZDD1 showing activation in concentrations 10 and 20 μg/mL and inhibition in concentrations 30, 40 and 50 μg/mL. TZDD4 showed activation in all the concentrations. In the β-amyloid aggregation assay, all the four derivatives showed inhibition activity ≥ 10% except TZDD1 at 50 μg/mL. Conclusions Diabetes mellitus and Alzheimer’s disease are a type of pathology of global concern, and several researchers worldwide have strived to search for novel therapeutic treatments and prevention for diabetes as well as Alzheimer’s disease. Recent studies provide a direct link v between diabetes mellitus and Alzheimer’s disease, and the need to find novel drugs that can mitigate these two is of increasing interest. In our search for antidiabetic and anti-Alzheimer’s activity, TZD derivatives (TZDD1, TZDD2, TZDD3 and TZDD4) exhibited good antioxidant activity, anti-hyperglycaemic activity and a relatively promising anti-Alzheimer’s activity. This was observed from the in vitro evaluation performed which included α – amylase, α – glucosidase, aldose reductase, PTP1B, DPP4, amyloid β aggregation, and AChE inhibition assays. Furthermore, docking of the derivatives against PPARγ predicted a similar molecular interaction to that of thiazolidinediones using Rosiglitazone as the standard drug. Furthermore, in silico ADME profiling predicted the derivatives to have moderate to good solubility in the GI (good GI bioavailability), and also exhibited excellent drug likeness. However, they are predicted not permeate the BBB. Further in silico studies and in vivo should be conducted to establish toxicities, as well as drug delivery to the brain for effective therapeutic effect against Alzheimer’s disease. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacology, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Arineitwe, Charles
- Date: 2022-04
- Subjects: Diabetes Treatment , Alzheimer's disease Treatment , Antioxidants Therapeutic use , Rosiglitazone , Hypoglycemic agents , In vitro screening , Thiazolidinedione Derivatives
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232171 , vital:49968
- Description: There is an increased prevalence of diabetes and other non-communicable diseases in Sub-Saharan Africa and globally. In South Africa, the prevalence of type 2 Diabetes mellitus is currently estimated at 9.0% in people aged 30 and older and is expected to increase. Diabetes-related complications result in acute alterations in the mental state due to poor metabolic control as well as greater rates of decline in cognitive functioning with age, higher prevalence of depression and increased risk of Alzheimer’s disease. Alzheimer’s disease is the most common form of dementia in older adults and possibly contributes to 60 - 70% of cases. Alzheimer’s disease remains incurable, its progression inevitable with the currently available symptomatic therapies being palliative while the treatment of diabetes relies on insulin preparations and other glucose-lowering agents. Current treatment options have numerous side effects such as hypoglycaemia, diarrhoea, weight gain and abnormal liver function. This has geared the investigation of new generations of small molecules which exhibit improved efficacy and safety profiles. On this basis, several studies have shown that thiazolidinediones and their corresponding derivatives exhibit a broad spectrum of biological activities including anti-inflammatory, and antioxidant activities. Furthermore, recent evidence from experimental, epidemiological, and clinical studies highlight the utility of antioxidants for treating diabetes and its complications. Interestingly, there is increasing evidence that links diabetes and Alzheimer’s disease due to their pathophysiology and suppressing glycaemia has been shown to be beneficial in Alzheimer’s disease treatment. Accordingly, the aim of this study, was to evaluate the anti-diabetic and anti-Alzheimer’s properties of four novel synthesized thiazolidinedione-derivatives owing to their antioxidant properties. Methods The aim of this study was achieved through performing ferric reducing antioxidant power activity, 2,2’-Diphenyl-1-Picry Hydrazyl radical scavenging activity, α-amylase inhibition, α-glucosidase inhibition, aldose reductase inhibition, protein tyrosine phosphatase-1B inhibition, dipeptidyl peptidase-4 inhibition, acetylcholinesterase inhibition, matrix metalloproteinase-1 inhibition, and β-amyloid aggregation inhibition assays. In addition, peroxisome proliferator-activated receptor-γ activation was performed through docking studies. To establish physicochemical properties of TZD derivatives investigated, further in-silico studies were done using SwissADME tools. Results To this end, in-vitro and in-silico studies were successfully performed. In-silico ADME profiling predicted these derivatives to be drug-like with moderate to good solubility in the GI and not blood-brain barrier permeable. Furthermore, docking of these molecules against PPARγ predicted a similar mode of action to that of thiazolidinediones using Rosiglitazone as the standard drug with TZDD2 and TZDD4 forming equivalent conformations to that of Rosiglitazone in the same binding site and TZDD3 having an equivalent LBE to that of Rosiglitazone (-8.84 and -8.63kcal/mol respectively). In-vitro evaluation predicted a moderate antioxidant activity with TZDD2 and 3 exhibiting the highest FRAP activity and DPPH radical scavenging activity. Furthermore, enzymatic inhibition assays showed a relative inhibition activity with TZDD3 exhibited > 100% inhibition in concentrations ≥ 30 μg/mL and TZDD1, 2 and 4 exhibited ≥ 50% inhibition activity in all the concentrations (10, 20, 30, 40 and 50 μg/mL) in the α-amylase inhibition assay. Similarly, in the α-glucosidase inhibition assay, all the four derivatives exhibited a concentration dependent activity with TZDD3 showing the most activity. All the four derivatives exhibited ≥ 30% inhibition in the aldose reductase inhibition assay except TZDD1 at 10 μg/mL. TZDD4 exhibited a concentration dependent inhibition activity in the protein tyrosine phosphatase-1B inhibition assay. Interestingly, TZDD3 showed a decreasing inhibition activity as its concentration increased from 10 μg/mL through to 50 μg/mL. In the dipeptidyl peptidase–4 inhibition assay, TZDD2 and TZDD4 exhibited ≥ 20% inhibition activity across all the concentrations and in the acetylcholinesterase assay, TZDD1, 3 and 4 exhibited ≥ 25% across all the concentrations. Interestingly, in the matrix metalloproteinase-1 inhibition assay, some of these derivatives exhibited partial activation activity and partial inhibition with TZDD1 showing activation in concentrations 10 and 20 μg/mL and inhibition in concentrations 30, 40 and 50 μg/mL. TZDD4 showed activation in all the concentrations. In the β-amyloid aggregation assay, all the four derivatives showed inhibition activity ≥ 10% except TZDD1 at 50 μg/mL. Conclusions Diabetes mellitus and Alzheimer’s disease are a type of pathology of global concern, and several researchers worldwide have strived to search for novel therapeutic treatments and prevention for diabetes as well as Alzheimer’s disease. Recent studies provide a direct link v between diabetes mellitus and Alzheimer’s disease, and the need to find novel drugs that can mitigate these two is of increasing interest. In our search for antidiabetic and anti-Alzheimer’s activity, TZD derivatives (TZDD1, TZDD2, TZDD3 and TZDD4) exhibited good antioxidant activity, anti-hyperglycaemic activity and a relatively promising anti-Alzheimer’s activity. This was observed from the in vitro evaluation performed which included α – amylase, α – glucosidase, aldose reductase, PTP1B, DPP4, amyloid β aggregation, and AChE inhibition assays. Furthermore, docking of the derivatives against PPARγ predicted a similar molecular interaction to that of thiazolidinediones using Rosiglitazone as the standard drug. Furthermore, in silico ADME profiling predicted the derivatives to have moderate to good solubility in the GI (good GI bioavailability), and also exhibited excellent drug likeness. However, they are predicted not permeate the BBB. Further in silico studies and in vivo should be conducted to establish toxicities, as well as drug delivery to the brain for effective therapeutic effect against Alzheimer’s disease. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacology, 2022
- Full Text:
- Date Issued: 2022-04
Industrial attachment and graduate employability in technical vocational education and training: a case of agriculture education in Zimbabwe
- Authors: Edziwa, Xavier
- Date: 2022-04
- Subjects: Vocational education -- Zimbabwe , College graduates -- Employment , Technical education -- Zimbabwe
- Language: English
- Type: Doctoral , Thesis
- Identifier: http://hdl.handle.net/10948/56022 , vital:54939
- Description: Institutions of higher learning, the world over, have adopted means of producing graduates that are work-ready and Zimbabwe is no exception. In Zimbabwe, a Commission of Inquiry into Education and Training recommended the introduction of vocational education and the introduction of a programme that improves the work-readiness of higher education graduates. This culminated in the institutions of higher education introducing industrial attachments in their curricular. This study was designed to explore the nature and implementation of industrial attachment by agricultural technical and vocational education and training institutions in Zimbabwe, as a way of enhancing students’ graduate attributes. It was done to hopefully improve policy and practice in the use of industrial attachment in imparting skills among college students. The research presented in this thesis, focuses on three case studies that were eclectically sampled, and data collected through focus group discussion with students and face-to-face individual interviews with college academia and workplace mentors. The study commenced by first establishing what stakeholders perceived as the employability skills expected of a graduate who has gone through an agricultural technical and vocational and training programme, and then explored how the IA programmes have been operationalised. Kolb’s experiential learning theory was used in the designing of research instruments and answering the research questions. The study established that the students generally perceived graduate attributes differently from academia and industry personnel. It was also established that current industrial attachment practices in agricultural training appear to favour production of graduates that are geared towards looking for employment, as opposed to the students’ perceptions that the 21st higher education institutions should produce graduates who create employment. While industrial attachment has been adopted by the institutions, this study identified a myriad of challenges that call for vii improvement in the practice if students are to benefit from the industrial attachment endeavours. The study ends by proposing a model that embraces students’ voice and is deemed to produce agricultural technical and vocational education and training graduates who are employment creators. , Thesis (PhD) -- Faculty of Education, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Edziwa, Xavier
- Date: 2022-04
- Subjects: Vocational education -- Zimbabwe , College graduates -- Employment , Technical education -- Zimbabwe
- Language: English
- Type: Doctoral , Thesis
- Identifier: http://hdl.handle.net/10948/56022 , vital:54939
- Description: Institutions of higher learning, the world over, have adopted means of producing graduates that are work-ready and Zimbabwe is no exception. In Zimbabwe, a Commission of Inquiry into Education and Training recommended the introduction of vocational education and the introduction of a programme that improves the work-readiness of higher education graduates. This culminated in the institutions of higher education introducing industrial attachments in their curricular. This study was designed to explore the nature and implementation of industrial attachment by agricultural technical and vocational education and training institutions in Zimbabwe, as a way of enhancing students’ graduate attributes. It was done to hopefully improve policy and practice in the use of industrial attachment in imparting skills among college students. The research presented in this thesis, focuses on three case studies that were eclectically sampled, and data collected through focus group discussion with students and face-to-face individual interviews with college academia and workplace mentors. The study commenced by first establishing what stakeholders perceived as the employability skills expected of a graduate who has gone through an agricultural technical and vocational and training programme, and then explored how the IA programmes have been operationalised. Kolb’s experiential learning theory was used in the designing of research instruments and answering the research questions. The study established that the students generally perceived graduate attributes differently from academia and industry personnel. It was also established that current industrial attachment practices in agricultural training appear to favour production of graduates that are geared towards looking for employment, as opposed to the students’ perceptions that the 21st higher education institutions should produce graduates who create employment. While industrial attachment has been adopted by the institutions, this study identified a myriad of challenges that call for vii improvement in the practice if students are to benefit from the industrial attachment endeavours. The study ends by proposing a model that embraces students’ voice and is deemed to produce agricultural technical and vocational education and training graduates who are employment creators. , Thesis (PhD) -- Faculty of Education, 2022
- Full Text:
- Date Issued: 2022-04