Microstructural characterization of Swift Heavy Ion (SHI) induced rotation in single crystal NiO
- Authors: Douglas-Henry, Danielle
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53648 , vital:45685
- Description: Swift Heavy Ions (SHI) are characterised by having energies greater than 1 MeV per nucleon with an atomic mass greater than 6 amu. Exposure to irradiation of this type has been known to produce latent tracks in insulators. This is due to the energy loss through the material being governed by electronic excitation processes. The extent of the track formation and microstructural changes induced has been reported to be material specific. Models such as the thermal spike model have been used to explain these changes, however rough approximations are still made. A particularly under studied phenomena is the collective rotation seen in materials exposed to off-normal incidence irradiation. To date the only available experimental data is X-Ray Diffraction (XRD) spectra and surface shifts. This does not allow for depth-dependent rotation studies and very little can be deduced regarding the microstructure of the modified volume. In this study, the microstructural changes in single crystal Nickel Oxide (NiO) have been studied using electron microscopy techniques. A depth dependent investigation of the crystal rotation was performed using Selected Area Electron Diffraction (SAED), Transmission Kikuchi Diffraction (TKD) and Electron Backscatter Diffraction (EBSD). Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) were utilized to interrogate the microstructural changes facilitating the bulk rotation. Five different NiO specimens were investigated. Specimens had surfaces parallel to either the {0 0 1} or {1 1 1} planes. Ion energies used were 593 MeV, 940 MeV and 1.6 GeV, while fluences ranged from 1.0 x 1011 ions/cm² to 9.6 x 1014 ions/cm². Latent track formation in both low fluence (nonoverlapping regime) and high fluence (overlapping regime) specimens were investigated and compared. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12
- Authors: Douglas-Henry, Danielle
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53648 , vital:45685
- Description: Swift Heavy Ions (SHI) are characterised by having energies greater than 1 MeV per nucleon with an atomic mass greater than 6 amu. Exposure to irradiation of this type has been known to produce latent tracks in insulators. This is due to the energy loss through the material being governed by electronic excitation processes. The extent of the track formation and microstructural changes induced has been reported to be material specific. Models such as the thermal spike model have been used to explain these changes, however rough approximations are still made. A particularly under studied phenomena is the collective rotation seen in materials exposed to off-normal incidence irradiation. To date the only available experimental data is X-Ray Diffraction (XRD) spectra and surface shifts. This does not allow for depth-dependent rotation studies and very little can be deduced regarding the microstructure of the modified volume. In this study, the microstructural changes in single crystal Nickel Oxide (NiO) have been studied using electron microscopy techniques. A depth dependent investigation of the crystal rotation was performed using Selected Area Electron Diffraction (SAED), Transmission Kikuchi Diffraction (TKD) and Electron Backscatter Diffraction (EBSD). Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) were utilized to interrogate the microstructural changes facilitating the bulk rotation. Five different NiO specimens were investigated. Specimens had surfaces parallel to either the {0 0 1} or {1 1 1} planes. Ion energies used were 593 MeV, 940 MeV and 1.6 GeV, while fluences ranged from 1.0 x 1011 ions/cm² to 9.6 x 1014 ions/cm². Latent track formation in both low fluence (nonoverlapping regime) and high fluence (overlapping regime) specimens were investigated and compared. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12
Development of a strategy to promote prenatal physical activity participation among women in Buffalo City Municipality, South Africa
- Okafor, Uchenna Benedine https://orcid.org/0000-0002-0435-2041
- Authors: Okafor, Uchenna Benedine https://orcid.org/0000-0002-0435-2041
- Date: 2022-03
- Subjects: Prenatal care , Exercise for pregnant women
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22919 , vital:53218
- Description: Research has proven that prenatal physical activity practice is associated with multiple health benefits; however, most women in South Africa rarely participate in prenatal physical activity. In contrast to more developed countries, there is dearth of research focusing specifically on prenatal physical activity and exercise among South African women. Nevertheless, in order to effectively, and strategically promote such prenatal activity, such information is important to plan for an intervention strategy. The main aim of this study was to assess the level, patterns, and associated factors of prenatal physical activity; beliefs, knowledge, attitudes, perceived benefits, and sources of information women received during pregnancy; and, furthermore, to develop an effective and relevant intervention strategy to facilitate the participation in this particular activity in Buffalo City Municipality, Eastern Cape, South Africa. Methods The study was a mixed-method, cross-sectional study design with both quantitative and qualitative data collection and analyses. The sequential explanatory design was adopted to merge and mix different datasets to be collected and analysed. The quantitative data involved a convenient sample of 1082 pregnant women in 12 randomly selected primary healthcare clinics offering antenatal health services in Buffalo City, Eastern Cape. The Pregnancy Physical Activity Questionnaire was interviewer-administered to women at each antenatal health clinic on pre-specified days, in a designated room allocated to the primary researcher by the health facility manager. The descriptive statistics were frequency distribution, percentages, mean and standard deviation. Furthermore, the bivariate and multivariate analyses were performed on two categories of participants, namely inactive or active, to determine the factors affecting prenatal physical activity behaviour. Furthermore, multiple logistic regression analyses were used to assess associations between physical activity and the predictor variables during pregnancy. Adjusted odds ratios with 95% confidence interval were applied to estimate factors associated with physical activity levels, and the associations between prenatal physical activity levels and socio-demographic, lifestyle, and obstetrics characteristics were determined using a chi-squared analyses. The significance level was set at p = 0.05. In addition, a qualitative descriptive approach was applied, using semi-structured face-to-face interviews with 15 purposively selected pregnant women, as well as 17 midwives offering antenatal health-care services to pregnant women in the 12 selected healthcare clinics. Qualitative data were analysed using a thematic content analysis. To develop the physical activity strategy for the promotion of prenatal physical activity practice, three frameworks were applied, namely the Strength, Weakness, Opportunity and Threat (SWOT), the Political, Economic Growth, Socio-Cultural, Technological, Laws and Environmental (PESTLE), and, lastly, the Build, Overcome, Explore and Minimise (BOEM) analytical frameworks. To facilitate the validation of the strategy, the findings were additionally analysed, after which, appropriate intervention strategies promoting prenatal physical activity were developed by again using the SWOT and PESTLE analytical strategic frameworks. This process involved a purposive sampling of seven experts with knowledge of and a proven academic and scholarly background in prenatal physical activity and maternal health. Next, the developed physical activity strategy was presented to various stakeholders, which included six primary healthcare managers, two midwives, and pregnant women purposively selected in each of the 12 chosen antenatal health clinics for the validation process. The stakeholders discussed, deliberated on, and provided comments and opinions of the feasibility and implementation of the developed prenatal physical activity for promotion of physical activity practices in the Eastern Cape Province. Results The findings of this particular study demonstrated low levels of prenatal physical activity among pregnant women, and, further indicated that the most preferred form of activity was light-intensity and household activities. Only 278 of the women (25.7%) met recommendations for prenatal activity (≥150 min moderate intensity exercise per week). The average time spent in moderate–vigorous physical activity was 151.6 min (95% CI: 147.2– 156.0). Most of the women participated in light exercises with a mean of 65.9% (95% CI: 64.8–67.0), and 47.6% (95% CI: 46.3–48.9) participated in household activities. The majority of the women did not receive physical activity advice during prenatal care sessions (64.7%). Lower age (<19 years) (adjusted odd ratio (AOR) = 0.3; CI: 0.16–0.76), semi-urban residence (AOR = 0.8; CI: 0.55–1.03), lower educational level (AOR = 0.5; CI: 0.20–0.71), unemployment (AOR = 0.5; CI: 0.29–0.77) and nulliparity (AOR = 0.6; CI: 0.28–1.31) were negatively associated with prenatal physical activity, while prenatal physical activity was positively associated with starting physical activity in the first trimester (AOR = 1.9; CI: 1.06–3.31) compared to other trimesters. In addition, the pregnant women were aware of the safety (88.2%) and benefits of physical activity for both mother and baby (79.6%), improved labour and delivery (93.1%), promote energy (89.0%), and should be discontinued when tired (76.6%). However, they also held the contradictory belief that pregnancy is “a time to rest” (56.5%). Furthermore, the most common sources of information about prenatal physical activity were the media, television, the radio and Internet-based websites (70.2%). Most women affirmed that prenatal physical activity reduced infant weight (61.4%), lessen moodiness (90.4), decreased risk of gestational diabetes mellitus (92.9%), pregnancy-induced hypertension (92.5%), and complications at birth (97.8%), while common negative perceptions included musculoskeletal discomfort (82.7%), and back pain (85.7%). The majority of women indicated that prenatal physical activity improved self-image (95.7%), sleep patterns (94.2%), and respiratory function (95.8%). The results from the quantitative data revealed that the major modifiable barriers to prenatal physical activity were tiredness (73.3%), lack of advice from healthcare professionals (nurses/midwives) (64.7%), low energy (64.5%), and non-accessibility to physical activity facilities (63.0%). The results were confirmed in the qualitative data, based on the Ecological Model, in which women also mentioned tiredness, work and household responsibilities, a lack of motivation, and the lack of physical activity advice and information on the relevant recommendations and guidelines. Overall, 62.4% women had high knowledge regarding prenatal physical activity; and half of the women showed a positive attitude toward it (50.1%). Whilst participants had knowledge of other types of antenatal exercises, 80.9% of the women had no knowledge of swimming exercise. Negative attitudes towards physical activity included the feeling of tiredness (67.7%), lack of interest (64.8%), and inadequate information on physical activity (59.5%). In addition, the study highlighted that midwives rarely educate and counsel pregnant women about prenatal physical activity during scheduled antenatal visits, which was attributed largely to the shortage of midwives handling many responsibilities at clinics. Nevertheless, the midwives did express a willingness to provide effective physical activity education and counselling on prenatal physical activity, if supported by relevant training and workshops. Furthermore, they further recommended the use of the Mom Connect application, which is a technological device designed by the National Department of Health, to distribute relevant information about maternal and child health. The prenatal physical activity strategies developed to address the above-mentioned and other barriers associated with prenatal physical activity include the use of scientific and technological innovations to provide basic information on prenatal physical activity to pregnant women by means of Mom Connect, and, by collaborating with the various cellphone and network companies in South Africa. Another strategy was to integrate prenatal physical activity training into the curricula of the existing higher institutions of learning that provide teaching of maternal health in the Eastern Cape Province. Additional strategies included the documentation and subsequent clarification of misconceptions about the safety concerns often associated with prenatal physical activity by making the documents accessible to all women at the clinics in the form of a small pamphlet or booklet. Lastly, stakeholders suggested that the government offer periodic prenatal physical activity campaigns, which should be presented in local community town halls and clinics and by other stakeholders to address the current lack of awareness and effectively eliminate misrepresentations and falsehoods around the safety of prenatal physical activity within geographical setting of the Eastern Cape Province. Conclusion Despite the advantages of prenatal physical activity practices, most pregnant women in South Africa do not participate in moderate-intensity physical activity. Notably, while women perceive prenatal physical activity as beneficial to both mother and baby, such theoretical knowledge is not easily translatable into practice. The predominant sources of information on prenatal physical activity are the television, the radio, and other media, which may be potentially misleading or contradictory to evidence-based physical activity practice. Furthermore, tiredness, a lack of time, work and household responsibilities, and a lack of motivation were major modifiable barriers to prenatal physical activity by the women. In addition, pregnant women rarely receive information on prenatal physical activity. Consequently, to address the needs of the pregnant women as highlighted in this study, a prenatal physical activity intervention strategy was developed and validated by key stakeholders to promote prenatal physical activity and exercise practice among women, taken in account the local context. , Thesis (PhD) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Okafor, Uchenna Benedine https://orcid.org/0000-0002-0435-2041
- Date: 2022-03
- Subjects: Prenatal care , Exercise for pregnant women
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22919 , vital:53218
- Description: Research has proven that prenatal physical activity practice is associated with multiple health benefits; however, most women in South Africa rarely participate in prenatal physical activity. In contrast to more developed countries, there is dearth of research focusing specifically on prenatal physical activity and exercise among South African women. Nevertheless, in order to effectively, and strategically promote such prenatal activity, such information is important to plan for an intervention strategy. The main aim of this study was to assess the level, patterns, and associated factors of prenatal physical activity; beliefs, knowledge, attitudes, perceived benefits, and sources of information women received during pregnancy; and, furthermore, to develop an effective and relevant intervention strategy to facilitate the participation in this particular activity in Buffalo City Municipality, Eastern Cape, South Africa. Methods The study was a mixed-method, cross-sectional study design with both quantitative and qualitative data collection and analyses. The sequential explanatory design was adopted to merge and mix different datasets to be collected and analysed. The quantitative data involved a convenient sample of 1082 pregnant women in 12 randomly selected primary healthcare clinics offering antenatal health services in Buffalo City, Eastern Cape. The Pregnancy Physical Activity Questionnaire was interviewer-administered to women at each antenatal health clinic on pre-specified days, in a designated room allocated to the primary researcher by the health facility manager. The descriptive statistics were frequency distribution, percentages, mean and standard deviation. Furthermore, the bivariate and multivariate analyses were performed on two categories of participants, namely inactive or active, to determine the factors affecting prenatal physical activity behaviour. Furthermore, multiple logistic regression analyses were used to assess associations between physical activity and the predictor variables during pregnancy. Adjusted odds ratios with 95% confidence interval were applied to estimate factors associated with physical activity levels, and the associations between prenatal physical activity levels and socio-demographic, lifestyle, and obstetrics characteristics were determined using a chi-squared analyses. The significance level was set at p = 0.05. In addition, a qualitative descriptive approach was applied, using semi-structured face-to-face interviews with 15 purposively selected pregnant women, as well as 17 midwives offering antenatal health-care services to pregnant women in the 12 selected healthcare clinics. Qualitative data were analysed using a thematic content analysis. To develop the physical activity strategy for the promotion of prenatal physical activity practice, three frameworks were applied, namely the Strength, Weakness, Opportunity and Threat (SWOT), the Political, Economic Growth, Socio-Cultural, Technological, Laws and Environmental (PESTLE), and, lastly, the Build, Overcome, Explore and Minimise (BOEM) analytical frameworks. To facilitate the validation of the strategy, the findings were additionally analysed, after which, appropriate intervention strategies promoting prenatal physical activity were developed by again using the SWOT and PESTLE analytical strategic frameworks. This process involved a purposive sampling of seven experts with knowledge of and a proven academic and scholarly background in prenatal physical activity and maternal health. Next, the developed physical activity strategy was presented to various stakeholders, which included six primary healthcare managers, two midwives, and pregnant women purposively selected in each of the 12 chosen antenatal health clinics for the validation process. The stakeholders discussed, deliberated on, and provided comments and opinions of the feasibility and implementation of the developed prenatal physical activity for promotion of physical activity practices in the Eastern Cape Province. Results The findings of this particular study demonstrated low levels of prenatal physical activity among pregnant women, and, further indicated that the most preferred form of activity was light-intensity and household activities. Only 278 of the women (25.7%) met recommendations for prenatal activity (≥150 min moderate intensity exercise per week). The average time spent in moderate–vigorous physical activity was 151.6 min (95% CI: 147.2– 156.0). Most of the women participated in light exercises with a mean of 65.9% (95% CI: 64.8–67.0), and 47.6% (95% CI: 46.3–48.9) participated in household activities. The majority of the women did not receive physical activity advice during prenatal care sessions (64.7%). Lower age (<19 years) (adjusted odd ratio (AOR) = 0.3; CI: 0.16–0.76), semi-urban residence (AOR = 0.8; CI: 0.55–1.03), lower educational level (AOR = 0.5; CI: 0.20–0.71), unemployment (AOR = 0.5; CI: 0.29–0.77) and nulliparity (AOR = 0.6; CI: 0.28–1.31) were negatively associated with prenatal physical activity, while prenatal physical activity was positively associated with starting physical activity in the first trimester (AOR = 1.9; CI: 1.06–3.31) compared to other trimesters. In addition, the pregnant women were aware of the safety (88.2%) and benefits of physical activity for both mother and baby (79.6%), improved labour and delivery (93.1%), promote energy (89.0%), and should be discontinued when tired (76.6%). However, they also held the contradictory belief that pregnancy is “a time to rest” (56.5%). Furthermore, the most common sources of information about prenatal physical activity were the media, television, the radio and Internet-based websites (70.2%). Most women affirmed that prenatal physical activity reduced infant weight (61.4%), lessen moodiness (90.4), decreased risk of gestational diabetes mellitus (92.9%), pregnancy-induced hypertension (92.5%), and complications at birth (97.8%), while common negative perceptions included musculoskeletal discomfort (82.7%), and back pain (85.7%). The majority of women indicated that prenatal physical activity improved self-image (95.7%), sleep patterns (94.2%), and respiratory function (95.8%). The results from the quantitative data revealed that the major modifiable barriers to prenatal physical activity were tiredness (73.3%), lack of advice from healthcare professionals (nurses/midwives) (64.7%), low energy (64.5%), and non-accessibility to physical activity facilities (63.0%). The results were confirmed in the qualitative data, based on the Ecological Model, in which women also mentioned tiredness, work and household responsibilities, a lack of motivation, and the lack of physical activity advice and information on the relevant recommendations and guidelines. Overall, 62.4% women had high knowledge regarding prenatal physical activity; and half of the women showed a positive attitude toward it (50.1%). Whilst participants had knowledge of other types of antenatal exercises, 80.9% of the women had no knowledge of swimming exercise. Negative attitudes towards physical activity included the feeling of tiredness (67.7%), lack of interest (64.8%), and inadequate information on physical activity (59.5%). In addition, the study highlighted that midwives rarely educate and counsel pregnant women about prenatal physical activity during scheduled antenatal visits, which was attributed largely to the shortage of midwives handling many responsibilities at clinics. Nevertheless, the midwives did express a willingness to provide effective physical activity education and counselling on prenatal physical activity, if supported by relevant training and workshops. Furthermore, they further recommended the use of the Mom Connect application, which is a technological device designed by the National Department of Health, to distribute relevant information about maternal and child health. The prenatal physical activity strategies developed to address the above-mentioned and other barriers associated with prenatal physical activity include the use of scientific and technological innovations to provide basic information on prenatal physical activity to pregnant women by means of Mom Connect, and, by collaborating with the various cellphone and network companies in South Africa. Another strategy was to integrate prenatal physical activity training into the curricula of the existing higher institutions of learning that provide teaching of maternal health in the Eastern Cape Province. Additional strategies included the documentation and subsequent clarification of misconceptions about the safety concerns often associated with prenatal physical activity by making the documents accessible to all women at the clinics in the form of a small pamphlet or booklet. Lastly, stakeholders suggested that the government offer periodic prenatal physical activity campaigns, which should be presented in local community town halls and clinics and by other stakeholders to address the current lack of awareness and effectively eliminate misrepresentations and falsehoods around the safety of prenatal physical activity within geographical setting of the Eastern Cape Province. Conclusion Despite the advantages of prenatal physical activity practices, most pregnant women in South Africa do not participate in moderate-intensity physical activity. Notably, while women perceive prenatal physical activity as beneficial to both mother and baby, such theoretical knowledge is not easily translatable into practice. The predominant sources of information on prenatal physical activity are the television, the radio, and other media, which may be potentially misleading or contradictory to evidence-based physical activity practice. Furthermore, tiredness, a lack of time, work and household responsibilities, and a lack of motivation were major modifiable barriers to prenatal physical activity by the women. In addition, pregnant women rarely receive information on prenatal physical activity. Consequently, to address the needs of the pregnant women as highlighted in this study, a prenatal physical activity intervention strategy was developed and validated by key stakeholders to promote prenatal physical activity and exercise practice among women, taken in account the local context. , Thesis (PhD) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-03
A critical assessment of credit provision governance in South Africa with a focus on balancing the rights and responsibilities of credit providers and consumers under Section 129 of the National Credit Act 34 of 2005
- Batchelor, Bronwyn Le Ann https://orcid.org/0000-0001-7300-131X
- Authors: Batchelor, Bronwyn Le Ann https://orcid.org/0000-0001-7300-131X
- Date: 2022-05
- Subjects: Debtor and creditor -- South Africa , Credit control -- Law and legislation -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/26715 , vital:65967
- Description: The National Credit Act of 2005 (the NCA), described as the fourth generation of consumer protection legislation in South Africa, is the product of an initiative by the Department of Trade and Industry to address the shortcomings of the third generation of consumer protection legislation, being the Usury Act 73 of 1968 and the Credit Agreements Act 75 of 1980. The NCA seeks to unify legislation and departs radically from the old dispensation. Its aims are, inter alia, to provide a fair and non-discriminatory marketplace, to prohibit unfair credit practices and reckless lending, to establish national norms and standards relating to consumer credit and to promote a consistent enforcement framework relating to consumer credit. Through enactment of the NCA the government appears to have focused on the protection of consumers through pre-enforcement procedures, prohibitions on reckless lending practices, prevention of over-indebtedness, alleviation of over indebtedness, and an array of other measures. This protection is deemed necessary due to the relative unequal bargaining power between the credit provider (provider) and the consumer at the time of conclusion of an agreement. This consumer protection has, however, sometimes come at the cost of provider protection. Despite these endeavours, there is still the inevitably common occurrence of breach of the agreement by consumers and the ensuing recovery process available to providers. The relationship between the two major role players – the provider and consumer - is the epicentre of any discussion, theory or legislative enactment pertaining to credit. This study commences with an examination of the historical background and rationale for the NCA, putting into context the rules and regulations which govern the relationship between the parties when an agreement is breached as well as the remedies and recourses that are available to the aggrieved party in terms of the NCA. The common law, which acts as a stabiliser especially when there are legislative changes, is examined in relation to preenforcement procedures, breach and the remedies as affected by the NCA. The equitable balancing of the rights and responsibilities of these two major role players is essential to the continued well-being of not only the parties but also the credit industry and economy as a whole. The most common way for individuals to purchase any large asset like a home or motor vehicle is to approach a financial institution for provision of a loan or credit agreement. To protect its interest, the financial institution would normally register a mortgage bond over the property or hold the title of the motor vehicle until all instalments have been settled. The problem arises when the consumer defaults on repayment of the loan or credit agreement. The financial institution would then be forced to institute legal proceedings to for example foreclose on the bond and repossess the property or motor vehicle. The preenforcement procedure finds itself in the centre of the tug of war between the parties in that this is the area and time that both parties require their rights and interests to be protected. The pre-enforcement procedures determine to a large extent, if properly implemented, how many agreements are seen to successful finalisation versus the alternative of those being cancelled and / or enforcement pursued through litigation by the provider. Successful implementation of agreements and repayment of debt would support a healthy credit industry and therefore, a strong economy. This is also the favoured outcome by the NCA. Section 129 of the NCA encapsulates the pre-enforcement procedure and thus determines balancing the parties’ rights and responsibilities through its interpretation and application. The section, however, would appear to fall short in that the delivery requirement of the notice is not adequately defined and has therefore resulted in many disputes, interpretations and two subsequent amendments to the section by the National Credit Amendment Act of 2014 and 2019. The purpose of this study is to critically analyse section 129 of the NCA and determine if the rights of both the consumer and provider have been equally protected, with particular reference to the burden of bringing the section 129 notice to the attention of the consumer. The question posed by all parties involved is always inevitably: Must the section 129 notice come to the actual knowledge of the consumer in order for it to be valid? The answer to this question has varied between two schools of thought. The first school of thought, being the pro-provider approach, answers the question in the negative and holds that as long as the provider has met certain delivery requirements their duty has been fulfilled whether or not the consumer actually receives the notice. The second school of thought, being the pro-consumer approach, answers the questions in the affirmative and requires the provider to carry the burden of ensuring the consumer actually receives the notice in order for it to be valid. There are numerous reasons in support of both schools of thought. It is hoped that this study will make a helpful contribution to the balanced interpretation of section 129. The study aims to provide a consistent interpretation of the section whilst balancing the rights of the consumer and provider respectively. , Thesis (LLD) -- Faculty of Law, 2022
- Full Text:
- Date Issued: 2022-05
- Authors: Batchelor, Bronwyn Le Ann https://orcid.org/0000-0001-7300-131X
- Date: 2022-05
- Subjects: Debtor and creditor -- South Africa , Credit control -- Law and legislation -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/26715 , vital:65967
- Description: The National Credit Act of 2005 (the NCA), described as the fourth generation of consumer protection legislation in South Africa, is the product of an initiative by the Department of Trade and Industry to address the shortcomings of the third generation of consumer protection legislation, being the Usury Act 73 of 1968 and the Credit Agreements Act 75 of 1980. The NCA seeks to unify legislation and departs radically from the old dispensation. Its aims are, inter alia, to provide a fair and non-discriminatory marketplace, to prohibit unfair credit practices and reckless lending, to establish national norms and standards relating to consumer credit and to promote a consistent enforcement framework relating to consumer credit. Through enactment of the NCA the government appears to have focused on the protection of consumers through pre-enforcement procedures, prohibitions on reckless lending practices, prevention of over-indebtedness, alleviation of over indebtedness, and an array of other measures. This protection is deemed necessary due to the relative unequal bargaining power between the credit provider (provider) and the consumer at the time of conclusion of an agreement. This consumer protection has, however, sometimes come at the cost of provider protection. Despite these endeavours, there is still the inevitably common occurrence of breach of the agreement by consumers and the ensuing recovery process available to providers. The relationship between the two major role players – the provider and consumer - is the epicentre of any discussion, theory or legislative enactment pertaining to credit. This study commences with an examination of the historical background and rationale for the NCA, putting into context the rules and regulations which govern the relationship between the parties when an agreement is breached as well as the remedies and recourses that are available to the aggrieved party in terms of the NCA. The common law, which acts as a stabiliser especially when there are legislative changes, is examined in relation to preenforcement procedures, breach and the remedies as affected by the NCA. The equitable balancing of the rights and responsibilities of these two major role players is essential to the continued well-being of not only the parties but also the credit industry and economy as a whole. The most common way for individuals to purchase any large asset like a home or motor vehicle is to approach a financial institution for provision of a loan or credit agreement. To protect its interest, the financial institution would normally register a mortgage bond over the property or hold the title of the motor vehicle until all instalments have been settled. The problem arises when the consumer defaults on repayment of the loan or credit agreement. The financial institution would then be forced to institute legal proceedings to for example foreclose on the bond and repossess the property or motor vehicle. The preenforcement procedure finds itself in the centre of the tug of war between the parties in that this is the area and time that both parties require their rights and interests to be protected. The pre-enforcement procedures determine to a large extent, if properly implemented, how many agreements are seen to successful finalisation versus the alternative of those being cancelled and / or enforcement pursued through litigation by the provider. Successful implementation of agreements and repayment of debt would support a healthy credit industry and therefore, a strong economy. This is also the favoured outcome by the NCA. Section 129 of the NCA encapsulates the pre-enforcement procedure and thus determines balancing the parties’ rights and responsibilities through its interpretation and application. The section, however, would appear to fall short in that the delivery requirement of the notice is not adequately defined and has therefore resulted in many disputes, interpretations and two subsequent amendments to the section by the National Credit Amendment Act of 2014 and 2019. The purpose of this study is to critically analyse section 129 of the NCA and determine if the rights of both the consumer and provider have been equally protected, with particular reference to the burden of bringing the section 129 notice to the attention of the consumer. The question posed by all parties involved is always inevitably: Must the section 129 notice come to the actual knowledge of the consumer in order for it to be valid? The answer to this question has varied between two schools of thought. The first school of thought, being the pro-provider approach, answers the question in the negative and holds that as long as the provider has met certain delivery requirements their duty has been fulfilled whether or not the consumer actually receives the notice. The second school of thought, being the pro-consumer approach, answers the questions in the affirmative and requires the provider to carry the burden of ensuring the consumer actually receives the notice in order for it to be valid. There are numerous reasons in support of both schools of thought. It is hoped that this study will make a helpful contribution to the balanced interpretation of section 129. The study aims to provide a consistent interpretation of the section whilst balancing the rights of the consumer and provider respectively. , Thesis (LLD) -- Faculty of Law, 2022
- Full Text:
- Date Issued: 2022-05
Establishment of human OCT4 as a putative HSP90 client protein: a case for HSP90 chaperoning pluripotency
- Authors: Sterrenberg, Jason Neville
- Date: 2015
- Subjects: Induced pluripotent stem cells , Heat shock proteins , Stem cells , Transcription factors , Molecular chaperones
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194010 , vital:45415 , 10.21504/10962/194010
- Description: The therapeutic potential of stem cells is already being harnessed in clinical trails. Of even greater therapeutic potential has been the discovery of mechanisms to reprogram differentiated cells into a pluripotent stem cell-like state known as induced pluripotent stem cells (iPSCs). Stem cell nature is governed and maintained by a hierarchy of transcription factors, the apex of which is OCT4. Although much research has elucidated the transcriptional regulation of OCT4, OCT4 regulated gene expression profiles and OCT4 transcriptional activation mechanisms in both stem cell biology and cellular reprogramming to iPSCs, the fundamental biochemistry surrounding the OCT4 transcription factor remains largely unknown. In order to analyze the biochemical relationship between HSP90 and human OCT4 we developed an exogenous active human OCT4 expression model with human OCT4 under transcriptional control of a constitutive promoter. We identified the direct interaction between HSP90 and human OCT4 despite the fact that the proteins predominantly display differential subcellular localizations. We show that HSP90 inhibition resulted in degradation of human OCT4 via the ubiquitin proteasome degradation pathway. As human OCT4 and HSP90 did not interact in the nucleus, we suggest that HSP90 functions in the cytoplasmic stabilization of human OCT4. Our analysis suggests HSP90 inhibition inhibits the transcriptional activity of human OCT4 dimers without affecting monomeric OCT4 activity. Additionally our data suggests that the HSP90 and human OCT4 complex is modulated by phosphorylation events either promoting or abrogating the interaction between HSP90 and human OCT4. Our data suggest that human OCT4 displays the characteristics describing HSP90 client proteins, therefore we identify human OCT4 as a putative HSP90 client protein. The regulation of the transcription factor OCT4 by HSP90 provides fundamental insights into the complex biochemistry of stem cell biology. This may also be suggestive that HSP90 not only regulates stem cell biology by maintaining routine cellular homeostasis but additionally through the direct regulation of pluripotency factors. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
- Full Text:
- Date Issued: 2015
- Authors: Sterrenberg, Jason Neville
- Date: 2015
- Subjects: Induced pluripotent stem cells , Heat shock proteins , Stem cells , Transcription factors , Molecular chaperones
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194010 , vital:45415 , 10.21504/10962/194010
- Description: The therapeutic potential of stem cells is already being harnessed in clinical trails. Of even greater therapeutic potential has been the discovery of mechanisms to reprogram differentiated cells into a pluripotent stem cell-like state known as induced pluripotent stem cells (iPSCs). Stem cell nature is governed and maintained by a hierarchy of transcription factors, the apex of which is OCT4. Although much research has elucidated the transcriptional regulation of OCT4, OCT4 regulated gene expression profiles and OCT4 transcriptional activation mechanisms in both stem cell biology and cellular reprogramming to iPSCs, the fundamental biochemistry surrounding the OCT4 transcription factor remains largely unknown. In order to analyze the biochemical relationship between HSP90 and human OCT4 we developed an exogenous active human OCT4 expression model with human OCT4 under transcriptional control of a constitutive promoter. We identified the direct interaction between HSP90 and human OCT4 despite the fact that the proteins predominantly display differential subcellular localizations. We show that HSP90 inhibition resulted in degradation of human OCT4 via the ubiquitin proteasome degradation pathway. As human OCT4 and HSP90 did not interact in the nucleus, we suggest that HSP90 functions in the cytoplasmic stabilization of human OCT4. Our analysis suggests HSP90 inhibition inhibits the transcriptional activity of human OCT4 dimers without affecting monomeric OCT4 activity. Additionally our data suggests that the HSP90 and human OCT4 complex is modulated by phosphorylation events either promoting or abrogating the interaction between HSP90 and human OCT4. Our data suggest that human OCT4 displays the characteristics describing HSP90 client proteins, therefore we identify human OCT4 as a putative HSP90 client protein. The regulation of the transcription factor OCT4 by HSP90 provides fundamental insights into the complex biochemistry of stem cell biology. This may also be suggestive that HSP90 not only regulates stem cell biology by maintaining routine cellular homeostasis but additionally through the direct regulation of pluripotency factors. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
- Full Text:
- Date Issued: 2015
International legal protection of women's reproductive rights: a comparative analysis of abortion laws and policies in four jurisdictions-Nigeria, Ghana, South Africa and U.S.A.
- Authors: Abiodun, Adeleke Funminiyi
- Date: 2010-10
- Subjects: Abortion -- Law and legislation , Reproductive right
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/25839 , vital:64491
- Description: The subject matter of abortion law is extremely broad and multi-disciplinary. While naturally having its basis in criminal and constitutional law of individual states, the global development of abortion discourse has been influenced by the need to protect the reproductive rights of women as a sub-set of international human rights laws; thereby advocating not only the decriminalisation of abortion but also, that individual State should take affirmative actions in promoting abortion as a right for every woman. However, that induced abortion is a punishable criminal act or a “protectable” woman’s reproductive right remains controversial due to the plethora of perspectives, beliefs and reservations held by different groups of people which are multi-dimensional and contradictory. This thesis therefore attempts a comparative study of abortion laws and policies in four jurisdictions: Nigeria and Ghana, operating criminalised abortion laws, South Africa and United States which operate liberalised/permissive abortion laws and policies. The study basically examines the legal status and reproductive rights of women to legal and safe abortion within the existing legal framework of national laws of the four selected jurisdictions vis-à-vis the legal protection offered by various international instruments on human rights. While we show that strict and restrictive abortion laws, and also, failure of States to create conditions for safe abortion constitute infractions of the reproductive rights of women, we submit further that over-liberalisation of abortion laws and policies could also amount to infringement of the basic rights of other people, thus there is need to ensure a legal and acceptable balance. The study finally acknowledges the role of international human rights laws in the protection of women’s right to legal and safe abortion but asserts that there can be no universally acceptable morality to which the whole world could subsume in term of women’s right to abortion due to the interplay of socio-cultural, religious, and moral affiliations of the people in different communities. , Thesis (LLD) -- Faculty of Law, 2010
- Full Text:
- Date Issued: 2010-10
- Authors: Abiodun, Adeleke Funminiyi
- Date: 2010-10
- Subjects: Abortion -- Law and legislation , Reproductive right
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/25839 , vital:64491
- Description: The subject matter of abortion law is extremely broad and multi-disciplinary. While naturally having its basis in criminal and constitutional law of individual states, the global development of abortion discourse has been influenced by the need to protect the reproductive rights of women as a sub-set of international human rights laws; thereby advocating not only the decriminalisation of abortion but also, that individual State should take affirmative actions in promoting abortion as a right for every woman. However, that induced abortion is a punishable criminal act or a “protectable” woman’s reproductive right remains controversial due to the plethora of perspectives, beliefs and reservations held by different groups of people which are multi-dimensional and contradictory. This thesis therefore attempts a comparative study of abortion laws and policies in four jurisdictions: Nigeria and Ghana, operating criminalised abortion laws, South Africa and United States which operate liberalised/permissive abortion laws and policies. The study basically examines the legal status and reproductive rights of women to legal and safe abortion within the existing legal framework of national laws of the four selected jurisdictions vis-à-vis the legal protection offered by various international instruments on human rights. While we show that strict and restrictive abortion laws, and also, failure of States to create conditions for safe abortion constitute infractions of the reproductive rights of women, we submit further that over-liberalisation of abortion laws and policies could also amount to infringement of the basic rights of other people, thus there is need to ensure a legal and acceptable balance. The study finally acknowledges the role of international human rights laws in the protection of women’s right to legal and safe abortion but asserts that there can be no universally acceptable morality to which the whole world could subsume in term of women’s right to abortion due to the interplay of socio-cultural, religious, and moral affiliations of the people in different communities. , Thesis (LLD) -- Faculty of Law, 2010
- Full Text:
- Date Issued: 2010-10
An in-depth investigation of an early literacy intervention in Grade R in the Eastern Cape Province, South Africa
- Authors: Hodgskiss, Jennifer Adelé
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366222 , vital:65844
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Hodgskiss, Jennifer Adelé
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366222 , vital:65844
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
Effect of pomegranate (Punica granatum L) peel powder meal on growth performance, gut integrity, haemato-biochemical indices, meat, and bone quality of broiler chickens
- Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
A case study assessment of the ecological and social status of the South African boat-based whale watching industry
- Authors: Tolsma, Minke
- Date: 2022-04
- Subjects: Whale watching --South Africa , Dolphin watching
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55887 , vital:54397
- Description: Boat-based whale-watching (BBWW) is a rapidly growing marine tourism industry globally and in South Africa (SA). BBWW in SA was established in 1998, and since then the number of permits available has doubled from 20 to 40. However, the establishment and past growth of the industry was undertaken without ecological research or impact assessments. Global research has shown that BBWW has the potential to cause short-term changes in cetacean behaviour and movement, which in turn can have long-term population-level consequences. National policies to grow ocean economies in SA may encourage excessive growth in the BBWW industry, impacting the ecological sustainability. In the absence of long-term impact data, the BBWW industry should be managed to minimise short-term changes. This study aimed to determine the social and ecological status of the SA BBWW industry, using Plettenberg Bay as a case study, to inform its long term sustainability. To achieve this aim: 1) the short-term behavioural and movement responses of six cetacean species to encounters with commercial BBWW vessels were measured; 2) the efficacy of three permit regulations (approach speed, approach angle, and encounter duration) to prevent short-term behavioural changes in three cetacean species was measured; 3) rates of compliance of BBWWoperators with current regulations were recorded; 4) BBWW tourists’ expectations of and satisfaction with the industry were investigated; as well as 5) operators’ views on the current permit regulations of the industry All research was conducted between September 2018 and November 2020 in Plettenberg Bay (SA) where two BBWW companies operating two vessels each are active. Three dolphin (bottlenose, common and humpback dolphins) and three whale (Bryde’s, humpback and southern right whales) species are targeted by the industry, and were encountered during this study. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Tolsma, Minke
- Date: 2022-04
- Subjects: Whale watching --South Africa , Dolphin watching
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55887 , vital:54397
- Description: Boat-based whale-watching (BBWW) is a rapidly growing marine tourism industry globally and in South Africa (SA). BBWW in SA was established in 1998, and since then the number of permits available has doubled from 20 to 40. However, the establishment and past growth of the industry was undertaken without ecological research or impact assessments. Global research has shown that BBWW has the potential to cause short-term changes in cetacean behaviour and movement, which in turn can have long-term population-level consequences. National policies to grow ocean economies in SA may encourage excessive growth in the BBWW industry, impacting the ecological sustainability. In the absence of long-term impact data, the BBWW industry should be managed to minimise short-term changes. This study aimed to determine the social and ecological status of the SA BBWW industry, using Plettenberg Bay as a case study, to inform its long term sustainability. To achieve this aim: 1) the short-term behavioural and movement responses of six cetacean species to encounters with commercial BBWW vessels were measured; 2) the efficacy of three permit regulations (approach speed, approach angle, and encounter duration) to prevent short-term behavioural changes in three cetacean species was measured; 3) rates of compliance of BBWWoperators with current regulations were recorded; 4) BBWW tourists’ expectations of and satisfaction with the industry were investigated; as well as 5) operators’ views on the current permit regulations of the industry All research was conducted between September 2018 and November 2020 in Plettenberg Bay (SA) where two BBWW companies operating two vessels each are active. Three dolphin (bottlenose, common and humpback dolphins) and three whale (Bryde’s, humpback and southern right whales) species are targeted by the industry, and were encountered during this study. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Repurposing a polymer precursor scaffold for medicinal application: Synthesis, characterization and biological evaluation of ferrocenyl 1,3-benzoxazine derivatives as potential antiprotozoal and anticancer agents
- Authors: Mbaba, Mziyanda
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/164502 , vital:41124 , DOI 10.21504/10962/164502
- Description: The benzoxazines are a prominent class of heterocyclic compounds that possess a multitude of properties. To this end, benzoxazine derivatives have been used as versatile compounds for various utilities ranging from biological applications to the fabrication of polymers. Particularly, the 1,3-benzoxazine scaffold has featured in several bioactive compounds showing antimalarial, anticancer and antibacterial activities. Traditionally, it has been employed as a substrate in the synthesis of polymers with appealing physical and chemical properties. Due to the increasing interest in the polymer application of 1,3-benzoxazines, research of the 1,3-benzoxazine motif for polymer synthesis has been prioritized over other applications including its medicinal potential. The continuous development of resistance to clinical anticancer and antimalarial drugs has necessitated the need for the search of innovative bioactive compounds as potential alternative medicinal agents. To address this, the field of medicinal chemistry is adapting new approaches to counter resistance by incorporating nonconventional chemical moieties such as organometallic complexes, like ferrocene, into bioactive chemical motifs to serve as novel compounds with medicinal benefits. Incorporation of ferrocene into known bioactive chemical moieties has been shown to impart beneficial biological effects into the resultant compounds, which include the introduction of novel, and sometimes varied, mechanistic modalities and enhanced potency. Presented with the benefits of this strategy, the current work aims to design and evaluate the pharmaceutical capacity of novel derivatives containing 1,3-benzoxazine scaffold (traditionally applied in polymer synthesis) hybridized with the organometallic ferrocene unit as bioactive agents. Using a combination of expedient synthetic procedures such as the Burke three-component Mannich-type condensation, Vilsmeier-Haack formylation and reductive amination, four series of ferrocenyl 1,3-benzoxazine derivatives were synthesized and their structures confirmed by common spectroscopic techniques: nuclear magnetic resonance (NMR), infrared spectroscopy (IR) and high-resolution mass spectrometry (HRMS). The target compounds were evaluated in vitro for potential antimalarial and anticancer activities against strains of the malaria parasite (Plasmodium falciparum 3D7 and Dd2) and the triple-negative breast cancer cell line HCC70. Compounds exhibited higher potency towards the Plasmodium falciparum strains with IC50 values in the low and sub-micromolar range in comparison to the breast cancer cell line against for which mid-molar activities were observed. To gain insight into the possible mode of action of ferrocenyl 1,3-benzoxazines, representative compounds showing most efficacy from each series were assessed for DNA binding affinity by employing UV-Vis and fluorescence DNA titration experiments. The selected compounds were found to interact with the DNA by binding to the minor groove, and these findings were confirmed by in silico ligand docking studies using a B-DNA structure as the receptor. Compound 3.16c (IC50: 0.261 μM [3D7], 0.599 μM [Dd2], 11.0 μM [HCC70]), which emerged as the most promising compound, was found to induce DNA damage in HCC70 cancer cells when investigated for effects of DNA interaction. Additionally, compound 3.16c displayed a higher binding constant (Kb) against DNA isolated from 3D7 Plasmodium falciparum trophozoites (Kb = 1.88×106 M-1) than the mammalian DNA (Kb = 6.33×104 M-1) from calf thymus, thus explaining the preferred selectivity of the compounds for the malaria parasite. Moreover, the investigated compounds demonstrated binding affinity for synthetic hemozoin, β-hematin. Collectively, these data suggest that the compounds possess a dual mode of action for antimalarial activity involving DNA interaction and hemozoin inhibition. , Thesis (PhD) -- Faculty of Science, Chemistry, 2020
- Full Text:
- Date Issued: 2020
- Authors: Mbaba, Mziyanda
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/164502 , vital:41124 , DOI 10.21504/10962/164502
- Description: The benzoxazines are a prominent class of heterocyclic compounds that possess a multitude of properties. To this end, benzoxazine derivatives have been used as versatile compounds for various utilities ranging from biological applications to the fabrication of polymers. Particularly, the 1,3-benzoxazine scaffold has featured in several bioactive compounds showing antimalarial, anticancer and antibacterial activities. Traditionally, it has been employed as a substrate in the synthesis of polymers with appealing physical and chemical properties. Due to the increasing interest in the polymer application of 1,3-benzoxazines, research of the 1,3-benzoxazine motif for polymer synthesis has been prioritized over other applications including its medicinal potential. The continuous development of resistance to clinical anticancer and antimalarial drugs has necessitated the need for the search of innovative bioactive compounds as potential alternative medicinal agents. To address this, the field of medicinal chemistry is adapting new approaches to counter resistance by incorporating nonconventional chemical moieties such as organometallic complexes, like ferrocene, into bioactive chemical motifs to serve as novel compounds with medicinal benefits. Incorporation of ferrocene into known bioactive chemical moieties has been shown to impart beneficial biological effects into the resultant compounds, which include the introduction of novel, and sometimes varied, mechanistic modalities and enhanced potency. Presented with the benefits of this strategy, the current work aims to design and evaluate the pharmaceutical capacity of novel derivatives containing 1,3-benzoxazine scaffold (traditionally applied in polymer synthesis) hybridized with the organometallic ferrocene unit as bioactive agents. Using a combination of expedient synthetic procedures such as the Burke three-component Mannich-type condensation, Vilsmeier-Haack formylation and reductive amination, four series of ferrocenyl 1,3-benzoxazine derivatives were synthesized and their structures confirmed by common spectroscopic techniques: nuclear magnetic resonance (NMR), infrared spectroscopy (IR) and high-resolution mass spectrometry (HRMS). The target compounds were evaluated in vitro for potential antimalarial and anticancer activities against strains of the malaria parasite (Plasmodium falciparum 3D7 and Dd2) and the triple-negative breast cancer cell line HCC70. Compounds exhibited higher potency towards the Plasmodium falciparum strains with IC50 values in the low and sub-micromolar range in comparison to the breast cancer cell line against for which mid-molar activities were observed. To gain insight into the possible mode of action of ferrocenyl 1,3-benzoxazines, representative compounds showing most efficacy from each series were assessed for DNA binding affinity by employing UV-Vis and fluorescence DNA titration experiments. The selected compounds were found to interact with the DNA by binding to the minor groove, and these findings were confirmed by in silico ligand docking studies using a B-DNA structure as the receptor. Compound 3.16c (IC50: 0.261 μM [3D7], 0.599 μM [Dd2], 11.0 μM [HCC70]), which emerged as the most promising compound, was found to induce DNA damage in HCC70 cancer cells when investigated for effects of DNA interaction. Additionally, compound 3.16c displayed a higher binding constant (Kb) against DNA isolated from 3D7 Plasmodium falciparum trophozoites (Kb = 1.88×106 M-1) than the mammalian DNA (Kb = 6.33×104 M-1) from calf thymus, thus explaining the preferred selectivity of the compounds for the malaria parasite. Moreover, the investigated compounds demonstrated binding affinity for synthetic hemozoin, β-hematin. Collectively, these data suggest that the compounds possess a dual mode of action for antimalarial activity involving DNA interaction and hemozoin inhibition. , Thesis (PhD) -- Faculty of Science, Chemistry, 2020
- Full Text:
- Date Issued: 2020
Exploring the value of an educational partnership within a multilingual pre-school setting
- Authors: Maritz, Anneliese
- Date: 2022-10-04
- Subjects: Early childhood education Parent participation South Africa Eastern Cape , Early childhood teachers Training of , Home and school South Africa Eastern Cape , Parent-teacher relationships South Africa Eastern Cape , Communication and education South Africa Eastern Cape
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327111 , vital:61082 , DOI 10.21504/10962/327111
- Description: This modest research project was situated in a multilingual Early Childhood Development (ECD) setting in the Eastern Cape (EC) province of South Africa. In the context of high levels of poverty and unemployment in the EC, issues such as under-funding, the nature of the training of practitioners, translating the importance of learning through play into practice, difficulties dealing with diverse cultural practices and the use of multiple languages, all impact ECD provision. Research has shown that parental involvement and creating parent-school partnerships can assist children to progress at school. The overall objectives of this project were to explore how a team in an ECD centre might communicate more effectively with parents and how early stimulation practices in home and school might benefit the child’s development. The theoretical framework draws upon Vygotsky’s (1978) socio-cultural historical theory, Bernstein’s (1971) elaborated and restricted language codes and Bourdieu’s (1977) concepts of social reproduction. A research project in the Netherlands Thuis in School, used an education partnership approach (Iliás et al., 2019). They developed a manual that was adapted for our local context by drawing from the theories mentioned, and to counter the dominant approaches where parenting programs have often been offered from a deficit, narrow perspective. Action Research guided the interventionist approach to workshop sessions, to enable mutual capacity-building of parents and practitioners. To ensure informed consent, participants’ first languages were used. High risk factors related to photographs and videos of participating parents and minor children were successfully addressed. Pre- and post-interviews and workshop data were analysed using template analysis, within a constructivist paradigm. Findings include vignettes to introduce the contexts and parents' ideas prior to the sessions. Then, sessions are summarised as action cycles, with key participants' responses. Finally, post-session evaluations highlight the topics the parents found most meaningful; and parents’ and practitioner accounts of changes in practices. This research illustrates ways that educational partnership elements can influence practice and policy, to improve home and school environments for the benefit of children. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
- Authors: Maritz, Anneliese
- Date: 2022-10-04
- Subjects: Early childhood education Parent participation South Africa Eastern Cape , Early childhood teachers Training of , Home and school South Africa Eastern Cape , Parent-teacher relationships South Africa Eastern Cape , Communication and education South Africa Eastern Cape
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327111 , vital:61082 , DOI 10.21504/10962/327111
- Description: This modest research project was situated in a multilingual Early Childhood Development (ECD) setting in the Eastern Cape (EC) province of South Africa. In the context of high levels of poverty and unemployment in the EC, issues such as under-funding, the nature of the training of practitioners, translating the importance of learning through play into practice, difficulties dealing with diverse cultural practices and the use of multiple languages, all impact ECD provision. Research has shown that parental involvement and creating parent-school partnerships can assist children to progress at school. The overall objectives of this project were to explore how a team in an ECD centre might communicate more effectively with parents and how early stimulation practices in home and school might benefit the child’s development. The theoretical framework draws upon Vygotsky’s (1978) socio-cultural historical theory, Bernstein’s (1971) elaborated and restricted language codes and Bourdieu’s (1977) concepts of social reproduction. A research project in the Netherlands Thuis in School, used an education partnership approach (Iliás et al., 2019). They developed a manual that was adapted for our local context by drawing from the theories mentioned, and to counter the dominant approaches where parenting programs have often been offered from a deficit, narrow perspective. Action Research guided the interventionist approach to workshop sessions, to enable mutual capacity-building of parents and practitioners. To ensure informed consent, participants’ first languages were used. High risk factors related to photographs and videos of participating parents and minor children were successfully addressed. Pre- and post-interviews and workshop data were analysed using template analysis, within a constructivist paradigm. Findings include vignettes to introduce the contexts and parents' ideas prior to the sessions. Then, sessions are summarised as action cycles, with key participants' responses. Finally, post-session evaluations highlight the topics the parents found most meaningful; and parents’ and practitioner accounts of changes in practices. This research illustrates ways that educational partnership elements can influence practice and policy, to improve home and school environments for the benefit of children. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
Neutral Atomic Hydrogen in Gravitationally Lensed Systems
- Authors: Blecher, Tariq Dylan
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192776 , vital:45263
- Description: Thesis (PhD) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Blecher, Tariq Dylan
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192776 , vital:45263
- Description: Thesis (PhD) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-10-29
An examination of human resource management strategies and their contribution to effective local government systems in Zimbabwe
- Mutongoreni, Noah Ariel https://orcid.org/0000-0002-6039-6241
- Authors: Mutongoreni, Noah Ariel https://orcid.org/0000-0002-6039-6241
- Date: 2015-01
- Subjects: Personnel management , Local government--Zimbabwe
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24024 , vital:62299
- Description: The study sought to examine human resource management strategies and their contributions to effective local government systems in Manicaland, Zimbabwe. Local government in Zimbabwe, though being nearest to the people, is showing evidence of failure to discharge its mandate. Various factors have been used to explain the reasons behind local government‘s failures to provide services. None of these have touched on the role played by people management in ensuring local government performance. This was notwithstanding the fact that towards the last two decades of the twentieth century research emerged glorifying human resources as the source of organizational excellence. Consequently, being motivated by the fact that good people management strategies lead to excellent organizational performance, attention in this study focused on people management strategies in local government in Zimbabwe. The study adopted a mixed approach with a strong inclination towards qualitative methodology. The data was gleaned from documents from local authorities, interviews, focus group interviews and questionnaire surveys. The study focused on local authorities in Manicaland Province. The results of the study confirmed the existence of human resource management strategies in local authorities in Manicaland, Zimbabwe. The human resource management strategies have however not resulted in excellent performance of local authorities. The reason behind this is attributable to severe resource constraints. Excellent people management strategies were found to be on paper as there were no resources to support them. The dearth of resources in local authorities was found to be attributed to the economic, political, legal and social factors engulfing the local government system in Zimbabwe. Consequently, local government in Zimbabwe remain stressed and in dire need of a ―Lazarus moment‖. There is an engineer with skills to construct dams to quench the thirst souls in the city but there are no resources to construct the dams. The fireman‘s truck rushes to quench a fire outbreak only to arrive at the scene with no water. In view of this, the study recommends that the review of the local government legal framework be speeded up and more autonomy be granted to local authorities. Such a review would have a bearing on the notion of decentralization, democratization and consequently economic development. In addition, government must seriously consider setting aside a portion of its budget towards support of local authorities. v Where democratic ethos exists, there is transparency, accountability, the rule of law and responsiveness. The human resource in local government would in turn promote democracy and excellence. Other strategies such as granting of garnishing powers to local authorities as well as giving their police arresting would further nourish their resource base. When this happen people management strategies would contribute to effective local government systems in Zimbabwe. Further studies on the contribution of human resource management strategies in effective local government systems after the complete overhaul of the current legislative regime would nonetheless be of interest to researchers. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015-01
- Authors: Mutongoreni, Noah Ariel https://orcid.org/0000-0002-6039-6241
- Date: 2015-01
- Subjects: Personnel management , Local government--Zimbabwe
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24024 , vital:62299
- Description: The study sought to examine human resource management strategies and their contributions to effective local government systems in Manicaland, Zimbabwe. Local government in Zimbabwe, though being nearest to the people, is showing evidence of failure to discharge its mandate. Various factors have been used to explain the reasons behind local government‘s failures to provide services. None of these have touched on the role played by people management in ensuring local government performance. This was notwithstanding the fact that towards the last two decades of the twentieth century research emerged glorifying human resources as the source of organizational excellence. Consequently, being motivated by the fact that good people management strategies lead to excellent organizational performance, attention in this study focused on people management strategies in local government in Zimbabwe. The study adopted a mixed approach with a strong inclination towards qualitative methodology. The data was gleaned from documents from local authorities, interviews, focus group interviews and questionnaire surveys. The study focused on local authorities in Manicaland Province. The results of the study confirmed the existence of human resource management strategies in local authorities in Manicaland, Zimbabwe. The human resource management strategies have however not resulted in excellent performance of local authorities. The reason behind this is attributable to severe resource constraints. Excellent people management strategies were found to be on paper as there were no resources to support them. The dearth of resources in local authorities was found to be attributed to the economic, political, legal and social factors engulfing the local government system in Zimbabwe. Consequently, local government in Zimbabwe remain stressed and in dire need of a ―Lazarus moment‖. There is an engineer with skills to construct dams to quench the thirst souls in the city but there are no resources to construct the dams. The fireman‘s truck rushes to quench a fire outbreak only to arrive at the scene with no water. In view of this, the study recommends that the review of the local government legal framework be speeded up and more autonomy be granted to local authorities. Such a review would have a bearing on the notion of decentralization, democratization and consequently economic development. In addition, government must seriously consider setting aside a portion of its budget towards support of local authorities. v Where democratic ethos exists, there is transparency, accountability, the rule of law and responsiveness. The human resource in local government would in turn promote democracy and excellence. Other strategies such as granting of garnishing powers to local authorities as well as giving their police arresting would further nourish their resource base. When this happen people management strategies would contribute to effective local government systems in Zimbabwe. Further studies on the contribution of human resource management strategies in effective local government systems after the complete overhaul of the current legislative regime would nonetheless be of interest to researchers. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015-01
Ultra-high precision machining of rapidly solidified aluminium (RSA) alloys for optics
- Authors: Odedeyi, Peter Babatunde
- Date: 2021-12
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55921 , vital:54400
- Description: The advancement of ultra-precision is one of the most adaptable machining processes in the manufacturing of very complex and high-quality surface structures for optics, industrial, medical, aerospace and communication applications. Studies have shown that single-point diamond turning has an outstanding ability to machine high-quality optical components at a nanometric scale. However, in a responsive cutting process, the nanometric machinability of these optical components can easily be affected by several factors. The call for increasing needs of optical systems has recently led to the development of newly modified aluminium grades of non-ferrous alloys characterized by finer microstructures, defined mechanical and physical properties. To date, there has been a lack of sufficient research into these new aluminium alloys. In modern ultra-precision machining, the high demands for smart and inexpensive cutting tools are becoming more relevant in recent precision machines. In monitoring and predicting high-quality surface, cutting forces in single point diamond turning are believed to be as critical as other machining processes due to their potential effects on the quality of surface roughness. Undermining such an important factor is a compromise between the machining process's efficiency and the increased cost of production. Therefore, a comprehensive scientific understanding of the Nano-cutting mechanics is critical, particularly on modelling and analysis of cutting force, surface roughness, chip vii formation, acoustic emission, material removal rates, and molecular dynamic simulation of the rapidly solidified aluminium alloys to bridge the gap between fundamentals and industrial-scale application. The study is divided into three essential sections. First, the development of a force sensor. Secondly, investigation of the effect of cutting parameters (i.e., cutting speed, feed rate, and cutting depth) on cutting force, acoustic emission (AE), material removal rate (MRR), chip formation, Nose radius, and surface roughness (Ra), which play a leading role in the determination of machine productivity and efficiency of single-point diamond turning of rapidly solidified aluminium alloys. Thirdly, a 3-D molecular dynamic (MD) simulation of RSA 6061 is also carried out to further understand the nanometric mechanism and characterization of the alloy. The experiment was mainly conducted using Precitech Nanoform ultra-grind 250 lathe machines on three different advanced optical aluminium alloys materials; these are RSA 443, RSA 905, and RSA 6061. , Thesis (PhD) -- Faculty of Engineering, the Built Environment and Information Technology, School of Engineering, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Odedeyi, Peter Babatunde
- Date: 2021-12
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55921 , vital:54400
- Description: The advancement of ultra-precision is one of the most adaptable machining processes in the manufacturing of very complex and high-quality surface structures for optics, industrial, medical, aerospace and communication applications. Studies have shown that single-point diamond turning has an outstanding ability to machine high-quality optical components at a nanometric scale. However, in a responsive cutting process, the nanometric machinability of these optical components can easily be affected by several factors. The call for increasing needs of optical systems has recently led to the development of newly modified aluminium grades of non-ferrous alloys characterized by finer microstructures, defined mechanical and physical properties. To date, there has been a lack of sufficient research into these new aluminium alloys. In modern ultra-precision machining, the high demands for smart and inexpensive cutting tools are becoming more relevant in recent precision machines. In monitoring and predicting high-quality surface, cutting forces in single point diamond turning are believed to be as critical as other machining processes due to their potential effects on the quality of surface roughness. Undermining such an important factor is a compromise between the machining process's efficiency and the increased cost of production. Therefore, a comprehensive scientific understanding of the Nano-cutting mechanics is critical, particularly on modelling and analysis of cutting force, surface roughness, chip vii formation, acoustic emission, material removal rates, and molecular dynamic simulation of the rapidly solidified aluminium alloys to bridge the gap between fundamentals and industrial-scale application. The study is divided into three essential sections. First, the development of a force sensor. Secondly, investigation of the effect of cutting parameters (i.e., cutting speed, feed rate, and cutting depth) on cutting force, acoustic emission (AE), material removal rate (MRR), chip formation, Nose radius, and surface roughness (Ra), which play a leading role in the determination of machine productivity and efficiency of single-point diamond turning of rapidly solidified aluminium alloys. Thirdly, a 3-D molecular dynamic (MD) simulation of RSA 6061 is also carried out to further understand the nanometric mechanism and characterization of the alloy. The experiment was mainly conducted using Precitech Nanoform ultra-grind 250 lathe machines on three different advanced optical aluminium alloys materials; these are RSA 443, RSA 905, and RSA 6061. , Thesis (PhD) -- Faculty of Engineering, the Built Environment and Information Technology, School of Engineering, 2021
- Full Text:
- Date Issued: 2021-12
Agro-morphological characterisation, nitrogen use efficiency and combining ability of quality protein maize (zea mays l.) genotypes for low nitrogen tolerance
- AdeOluwa, Olusola Oluyinka https://orcid.org/ 0000-0003-2145-7141
- Authors: AdeOluwa, Olusola Oluyinka https://orcid.org/ 0000-0003-2145-7141
- Date: 2021-08
- Subjects: Corn -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21501 , vital:48855 , http://id.loc.gov/authorities/subjects/sh85032715
- Description: Low nitrogen stress tolerant Quality Protein Maize (QPM) genotypes will be of great benefit to farmers for increasing productivity in nitrogen depleted soils in the Eastern Cape (EC) Province, South Africa (SA). The current study evaluated: (i) QPM inbred lines for tolerance to low soil nitrogen, (ii) the Nitrogen Use Efficiency (NUE) of different QPM inbred lines, (iii) the combining ability of QPM genotypes for tolerance to low nitrogen, grain yield, and other agro-morphological traits, and (iv) the agro-morphological characteristics and adaptation of QPM hybrids to environments of different production potential in the Eastern Cape, South Africa. Thirty-two white-seeded QPM inbred lines obtained from CIMMYT-Zimbabwe and Quality Seeds (PTY) LTD were evaluated for tolerance to low soil nitrogen stress using two nitrogen (N) treatment levels: 0 kg N ha-1 and 30 kg N ha-1 under both glasshouse and field conditions at the Crop Research farm, University of Fort Hare, in two planting seasons. The study aimed at assessing the response of QPM inbred lines to low N, with a view to identifying low N tolerant types under both glasshouse and field conditions. Shoot length stress tolerance index (SHL STI) indicated lines L23, L29, L27, L13, L16, L17, L31, L14, L18 and L22 to be low soil N tolerant from the glasshouse study. From the field study, low N Stress Tolerance Index (STI) identified inbred lines L23, L31, L26, L28, L25, L29, L32, L4, L6, L3 and L2 as low soil N tolerant. These inbred lines also had high grain yields (GY) in the field under 0 kg N ha-1 (all ranked within the top ten except L2). They also had the potential for stable yields across environments considering their high Yield Stability Index (YSI), Mean Productivity (MP), Geometric Mean Productivity (GMP) and Stress Susceptibility Index (SSI) values. Both the glasshouse and field studies revealed inbred lines L22, L23, L26, L28, L25, L29 and L31 were common to both the glasshouse and field studies as being low soil N tolerant. These thirty-two parental QPM inbred lines were evaluated in the field for their nitrogen use efficiency (NUE) under five different nitrogen levels: 0, 30, 60, 90 and 120 kg N ha-1. The inbred lines studied under 0 kg N ha-1 and 30 kg N ha-1 indicated that N level expressed highly significant differences (P ≤ 0.001) for total nitrogen in biomass (Bio Total N), total nitrogen in grain (G Total N), grain yield (GY), nitrogen use efficiency (NUE) and almost all the indices estimated. The top six nutrient use efficient genotypes were L9, L14, L23, L25, L29 and L32 across N levels. However, the best and highest NUE was obtained from the lowest fertilizer dose, 30 kg N ha-1. Highly significant and positive correlation coefficients were found between Nitrogen Use Efficiency (NUE) and yield (+0.9), NUE and NUtE (+0.9), NUE and HI (Harvest Index) (+0.5), NUtE and yield (+0.99), HI and yield (+0.5) and NUtE and HI (+0.5). Thus, NUE, HI and NUtE could be good predictors of yield potential under low N soil conditions. Sixty-four testcross hybrids were generated from crossing these 32 QPM inbred lines with two QPM open pollinated varieties (OPVs) as testers in a line x tester design and were evaluated under 0 kg N ha-1 and 30 kg N ha-1 in the field. The objectives of the experiment were to: (i) identify high yielding hybrids with tolerance to low soil N in the EC; (ii) determine the combining abilities and mode of gene action for various traits under low and high nitrogen conditions; and (iii) group the inbred lines into heterotic groups for future use in the breeding program. Results revealed that under 30 kg N ha-1 (30N) condition, both additive and non-additive gene effects were observed with less importance of non-additive gene action for grain yield. Based on specific combining ability (SCA) effects, hybrids LNC22, LNC31, LOB22, LNC30, LNC29, LOB11, LNC18, LOB30, LOB19 and LNC24 showed outstanding performance under 0 kg N ha-1 (0N) condition with relatively acceptable SCA under 30N for yield. Inbred lines L6 (1.63), L22 (1.74), L29 (1.83) and L30 (1.24) showed positive and significant GCAs for grain yield under 0N. They were identified as the best combiners for grain yield as they were among the top ten performers for GCA under 0N. They can be very useful sources of low N tolerance genes. Two heterotic groups were formed under 0 kg N ha-1 and 30 kg N ha-1 conditions, and they will be useful for future hybrid development in the breeding program. Furthermore, these thirty-two QPM inbred lines were utilised as parental lines to generate seventy-six single cross hybrids. These single cross hybrids were evaluated across three environments of varying production potential in the Eastern Cape (EC), during the 2016/17 and 2017/18 summer seasons. Non-QPM hybrids namely PAN5Q649R and Phb31MO7BR, as well as QPM OPVs OBATANPA and Nelson's Choice were included in these preliminary variety trials (PVTs) as checks. Twenty-five hybrids expressing high values for the Smith – Hazel selection index were identified across sites over years. Among those hybrids were two checks, namely Q16 (PAN5Q649R) and Q33 (Phb31MO7BR). The top five high – yielding hybrids selected based on the selection index were considered to be the most productive, stable and adaptable based on the GGE biplot and AMMI stability values. None of these single cross hybrids over yielded the best hybrid check (Q16) in the current study. A high potential environment, Centane, was the ideal environments for evaluating genotypes in the present study. The studies showed inbred lines L22, L23, L26, L28, L25, L29 and L31 to be low N stress tolerant at 0 kg N ha-1 based on the low N stress tolerance indices under glasshouse and the field conditions; they were also among the top ten grain-yielders under field conditions at 0 kg N ha-1. Also, in the NUE study, they were found to be among the top ten most N-efficient inbred lines under low N soils, under 30 kg N ha-1, and were among the top twenty-four inbred lines with high NUE values across the N levels in the study. Inbred lines L29 and L22 also produced testcross hybrids that were among the top twenty based on GY under 0 kg N ha-1. The testcross hybrids produced from these inbred lines were also among the top twenty-five with outstanding SCA effects for GY. These inbred lines were also parental lines of some of the top twenty- five best hybrids selected based on the Smith – Hazel selection index in the PVT study. Inbred lines L22, L23, L26, L28, L25, L29 and L31 can therefore further be evaluated and used as sources of N-tolerance genes in QPM breeding programs. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-08
- Authors: AdeOluwa, Olusola Oluyinka https://orcid.org/ 0000-0003-2145-7141
- Date: 2021-08
- Subjects: Corn -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21501 , vital:48855 , http://id.loc.gov/authorities/subjects/sh85032715
- Description: Low nitrogen stress tolerant Quality Protein Maize (QPM) genotypes will be of great benefit to farmers for increasing productivity in nitrogen depleted soils in the Eastern Cape (EC) Province, South Africa (SA). The current study evaluated: (i) QPM inbred lines for tolerance to low soil nitrogen, (ii) the Nitrogen Use Efficiency (NUE) of different QPM inbred lines, (iii) the combining ability of QPM genotypes for tolerance to low nitrogen, grain yield, and other agro-morphological traits, and (iv) the agro-morphological characteristics and adaptation of QPM hybrids to environments of different production potential in the Eastern Cape, South Africa. Thirty-two white-seeded QPM inbred lines obtained from CIMMYT-Zimbabwe and Quality Seeds (PTY) LTD were evaluated for tolerance to low soil nitrogen stress using two nitrogen (N) treatment levels: 0 kg N ha-1 and 30 kg N ha-1 under both glasshouse and field conditions at the Crop Research farm, University of Fort Hare, in two planting seasons. The study aimed at assessing the response of QPM inbred lines to low N, with a view to identifying low N tolerant types under both glasshouse and field conditions. Shoot length stress tolerance index (SHL STI) indicated lines L23, L29, L27, L13, L16, L17, L31, L14, L18 and L22 to be low soil N tolerant from the glasshouse study. From the field study, low N Stress Tolerance Index (STI) identified inbred lines L23, L31, L26, L28, L25, L29, L32, L4, L6, L3 and L2 as low soil N tolerant. These inbred lines also had high grain yields (GY) in the field under 0 kg N ha-1 (all ranked within the top ten except L2). They also had the potential for stable yields across environments considering their high Yield Stability Index (YSI), Mean Productivity (MP), Geometric Mean Productivity (GMP) and Stress Susceptibility Index (SSI) values. Both the glasshouse and field studies revealed inbred lines L22, L23, L26, L28, L25, L29 and L31 were common to both the glasshouse and field studies as being low soil N tolerant. These thirty-two parental QPM inbred lines were evaluated in the field for their nitrogen use efficiency (NUE) under five different nitrogen levels: 0, 30, 60, 90 and 120 kg N ha-1. The inbred lines studied under 0 kg N ha-1 and 30 kg N ha-1 indicated that N level expressed highly significant differences (P ≤ 0.001) for total nitrogen in biomass (Bio Total N), total nitrogen in grain (G Total N), grain yield (GY), nitrogen use efficiency (NUE) and almost all the indices estimated. The top six nutrient use efficient genotypes were L9, L14, L23, L25, L29 and L32 across N levels. However, the best and highest NUE was obtained from the lowest fertilizer dose, 30 kg N ha-1. Highly significant and positive correlation coefficients were found between Nitrogen Use Efficiency (NUE) and yield (+0.9), NUE and NUtE (+0.9), NUE and HI (Harvest Index) (+0.5), NUtE and yield (+0.99), HI and yield (+0.5) and NUtE and HI (+0.5). Thus, NUE, HI and NUtE could be good predictors of yield potential under low N soil conditions. Sixty-four testcross hybrids were generated from crossing these 32 QPM inbred lines with two QPM open pollinated varieties (OPVs) as testers in a line x tester design and were evaluated under 0 kg N ha-1 and 30 kg N ha-1 in the field. The objectives of the experiment were to: (i) identify high yielding hybrids with tolerance to low soil N in the EC; (ii) determine the combining abilities and mode of gene action for various traits under low and high nitrogen conditions; and (iii) group the inbred lines into heterotic groups for future use in the breeding program. Results revealed that under 30 kg N ha-1 (30N) condition, both additive and non-additive gene effects were observed with less importance of non-additive gene action for grain yield. Based on specific combining ability (SCA) effects, hybrids LNC22, LNC31, LOB22, LNC30, LNC29, LOB11, LNC18, LOB30, LOB19 and LNC24 showed outstanding performance under 0 kg N ha-1 (0N) condition with relatively acceptable SCA under 30N for yield. Inbred lines L6 (1.63), L22 (1.74), L29 (1.83) and L30 (1.24) showed positive and significant GCAs for grain yield under 0N. They were identified as the best combiners for grain yield as they were among the top ten performers for GCA under 0N. They can be very useful sources of low N tolerance genes. Two heterotic groups were formed under 0 kg N ha-1 and 30 kg N ha-1 conditions, and they will be useful for future hybrid development in the breeding program. Furthermore, these thirty-two QPM inbred lines were utilised as parental lines to generate seventy-six single cross hybrids. These single cross hybrids were evaluated across three environments of varying production potential in the Eastern Cape (EC), during the 2016/17 and 2017/18 summer seasons. Non-QPM hybrids namely PAN5Q649R and Phb31MO7BR, as well as QPM OPVs OBATANPA and Nelson's Choice were included in these preliminary variety trials (PVTs) as checks. Twenty-five hybrids expressing high values for the Smith – Hazel selection index were identified across sites over years. Among those hybrids were two checks, namely Q16 (PAN5Q649R) and Q33 (Phb31MO7BR). The top five high – yielding hybrids selected based on the selection index were considered to be the most productive, stable and adaptable based on the GGE biplot and AMMI stability values. None of these single cross hybrids over yielded the best hybrid check (Q16) in the current study. A high potential environment, Centane, was the ideal environments for evaluating genotypes in the present study. The studies showed inbred lines L22, L23, L26, L28, L25, L29 and L31 to be low N stress tolerant at 0 kg N ha-1 based on the low N stress tolerance indices under glasshouse and the field conditions; they were also among the top ten grain-yielders under field conditions at 0 kg N ha-1. Also, in the NUE study, they were found to be among the top ten most N-efficient inbred lines under low N soils, under 30 kg N ha-1, and were among the top twenty-four inbred lines with high NUE values across the N levels in the study. Inbred lines L29 and L22 also produced testcross hybrids that were among the top twenty based on GY under 0 kg N ha-1. The testcross hybrids produced from these inbred lines were also among the top twenty-five with outstanding SCA effects for GY. These inbred lines were also parental lines of some of the top twenty- five best hybrids selected based on the Smith – Hazel selection index in the PVT study. Inbred lines L22, L23, L26, L28, L25, L29 and L31 can therefore further be evaluated and used as sources of N-tolerance genes in QPM breeding programs. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-08
Views of the journey of grade 1 learners with barriers to learning, in the inclusive education system: a multi-level systemic investigation
- Van Vuuren, Cornelia Margaretha
- Authors: Van Vuuren, Cornelia Margaretha
- Date: 2022-10-04
- Subjects: Inclusive education South Africa Eastern Cape , Special education teachers South Africa Eastern Cape Attitudes , South Africa. Department of Education , Children with disabilities Education (Elementary) Government policy South Africa , Special education teachers Training of South Africa Eastern Cape
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327122 , vital:61083 , DOI 10.21504/10962/327122
- Description: Embedded in South Africa’s humanitarian discourse, inclusive education (IE) followed global trends of inclusion of all people into wider society without discrimination. Inclusion in mainstream schools should also, according to the Salamanca agreement provide equal quality education, enabling learners with special educational needs (LSEN) to reach their full potential as a basic human right. IE started in South Africa with the implementation of the inclusive policy EWP6 in 2001. Including all children with barriers to learning in schools in their communities promoted social inclusion with their peers. The DoE introduced the Policy of Screening, Identification, Assessment and Support (SIAS) in 2014. This policy was implemented to assist teachers to identify learning barriers, as a means of offering support to these learners through the inclusive system. However, it seems that educators found this process cumbersome, without resources to maintain the process and with multiple systemic barriers preventing, rather than enhancing, support to LSEN. This multi-level systemic study explores the views of educators and other stakeholders on the effectiveness of the IE system in supporting LSEN, to serve the best interests of these learners in their first year of formal schooling. The study was conducted in three selected diverse mainstream Eastern Cape (EC) rural schools, involving the views of educators, district officials and parents. The study probed the impact of the inclusive system on LSEN’s development and social wellbeing, the perceived effects and benefits of the current system, and how the education model contributes towards human rights objectives and constitutional imperatives. The study acknowledges the theories and policies of the current inclusive system as promoting inclusion, but not being successfully realised in rural areas in the South African context, due to several systemic and contextual barriers. The findings revealed that although all participants noted the possible benefits of IE, the current system did not serve the individual educational needs of LSEN in rural mainstream schools, in their first formal year of schooling. Several constraints were reported including lack of resources, insufficient Allied Health support services, and insufficient training of educators. These lead to feelings of inadequacy in educators, along with systemic and contextual barriers and financial constraints in the schools. There also seems to be a need for better collaboration between education and other departments serving children and communities. To conclude, this study suggests a broader multi-level networked system, in which there needs to be greater interaction between the DoE and other government departments supporting children with barriers, like the Departments of Health (DoH), Social Development (DSD) and Justice (DoJ). , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
- Authors: Van Vuuren, Cornelia Margaretha
- Date: 2022-10-04
- Subjects: Inclusive education South Africa Eastern Cape , Special education teachers South Africa Eastern Cape Attitudes , South Africa. Department of Education , Children with disabilities Education (Elementary) Government policy South Africa , Special education teachers Training of South Africa Eastern Cape
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327122 , vital:61083 , DOI 10.21504/10962/327122
- Description: Embedded in South Africa’s humanitarian discourse, inclusive education (IE) followed global trends of inclusion of all people into wider society without discrimination. Inclusion in mainstream schools should also, according to the Salamanca agreement provide equal quality education, enabling learners with special educational needs (LSEN) to reach their full potential as a basic human right. IE started in South Africa with the implementation of the inclusive policy EWP6 in 2001. Including all children with barriers to learning in schools in their communities promoted social inclusion with their peers. The DoE introduced the Policy of Screening, Identification, Assessment and Support (SIAS) in 2014. This policy was implemented to assist teachers to identify learning barriers, as a means of offering support to these learners through the inclusive system. However, it seems that educators found this process cumbersome, without resources to maintain the process and with multiple systemic barriers preventing, rather than enhancing, support to LSEN. This multi-level systemic study explores the views of educators and other stakeholders on the effectiveness of the IE system in supporting LSEN, to serve the best interests of these learners in their first year of formal schooling. The study was conducted in three selected diverse mainstream Eastern Cape (EC) rural schools, involving the views of educators, district officials and parents. The study probed the impact of the inclusive system on LSEN’s development and social wellbeing, the perceived effects and benefits of the current system, and how the education model contributes towards human rights objectives and constitutional imperatives. The study acknowledges the theories and policies of the current inclusive system as promoting inclusion, but not being successfully realised in rural areas in the South African context, due to several systemic and contextual barriers. The findings revealed that although all participants noted the possible benefits of IE, the current system did not serve the individual educational needs of LSEN in rural mainstream schools, in their first formal year of schooling. Several constraints were reported including lack of resources, insufficient Allied Health support services, and insufficient training of educators. These lead to feelings of inadequacy in educators, along with systemic and contextual barriers and financial constraints in the schools. There also seems to be a need for better collaboration between education and other departments serving children and communities. To conclude, this study suggests a broader multi-level networked system, in which there needs to be greater interaction between the DoE and other government departments supporting children with barriers, like the Departments of Health (DoH), Social Development (DSD) and Justice (DoJ). , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
Effect of Helicosporidium sp. (Chlorophyta; Trebouxiophyceae) infection on Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae), a biological control agent for the invasive Salvinia molesta D.S. Mitchell (Salviniaceae) in South
- Authors: Mphephu, Tshililo Emmanuel
- Date: 2022-10-14
- Subjects: Salvinia molesta South Africa , Weeds Biological control , Cyrtobagous salviniae , Ketoconazole
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365815 , vital:65792 , DOI https://doi.org/10.21504/10962/365815
- Description: The effectiveness of established biological control agents depends on biotic and abiotic interactions in the introduced range. The weevil, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae), was released as a biological control against Salvinia molesta D.S. Mitchell (Salviniaceae) in South Africa in 1985. This agent has been highly successful against S. molesta and has significantly reduced the weed’s populations around the country. However, in 2007, the parasitic alga, Helicosporidium sp. (an undescribed species), was detected in field-collected C. salviniae adults in South Africa. The distribution and impacts of this disease on the weevil and its efficacy as a control agent were not known. In this thesis, the prevalence, infection load, and impact of Helicosporidium sp. on C. salviniae was determined. In 2019, adult weevils were collected from 10 sites across the Eastern Cape, KwaZulu-Natal, Limpopo, and Western Cape provinces and screened to determine the occurrence, infection load, and geographic distribution of Helicosporidium sp. Transmission mechanisms of this disease in C. salviniae were then evaluated. The possible impact of Helicosporidium sp. was assessed by comparing the feeding rates and the reproductive output of the diseased and healthy adults of C. salviniae. An attempt was then made to eliminate the disease in C. salviniae through the application of the antibiotic, ketoconazole. Further, the role of temperature on infection load in C. salviniae was also assessed. Finally, recommendations for the long-term biological control programme against S. molesta in South Africa were made. The disease covers the entire distribution range of C. salviniae in South Africa, with the disease occurrence rate ranging from 92.15% to 100% insects infected per site. Helicosporidium sp. was found to transmit vertically within the populations of C. salviniae. Infection by the Helicosporidium sp. disease reduced the reproductive output of C. salviniae as well its impact on biomass reduction of S. molesta when a diseased culture was compared to a healthy culture from the USA. 98.44 to 98.55% of Helicosporidium sp. loads were reduced through multiple applications of ketoconazole concentrations under in vitro trials. In vivo treatments resulted in 70% control of Helicosporidium sp. in the adults of C. salviniae that were fed ketoconazole three times over a 21 day period. Adult C. salviniae feeding and survival performances were similar when fed fronds of S. molesta inoculated with ketoconazole and water. The lowest and highest disease loads of Helicosporidium sp. were recorded when the weevils were reared at 30°C and 14°C, respectively. As expected, the highest impact and reproductive output of C. salviniae were at 30°C. The evaluations discussed in this thesis highlight the role of diseases in biological control agents, and gaps in both the pre-release and post-release monitoring that should integrate screening of diseases in these studies. Although the combined application of the antibiotic and temperature will reduce Helicosporidium sp. loads and impact, this technology is most likely only applicable where the weevils are reared in small numbers in a rearing facility and not really applicable to the field situation. It is important to release healthy agents that will cause efficient control of the target weed plant species, therefore, when introducing new biological control agents, the health status of such agents needs to be understood. Therefore, long-term field monitoring and assessment of the impact of C. salviniae on S. molesta should be conducted to track all the changes that may result due to the presence of Helicosporidium sp. This long-term monitoring and assessment will give a more informative role of Helicosporidium sp. in field populations of C. salviniae. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Mphephu, Tshililo Emmanuel
- Date: 2022-10-14
- Subjects: Salvinia molesta South Africa , Weeds Biological control , Cyrtobagous salviniae , Ketoconazole
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365815 , vital:65792 , DOI https://doi.org/10.21504/10962/365815
- Description: The effectiveness of established biological control agents depends on biotic and abiotic interactions in the introduced range. The weevil, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae), was released as a biological control against Salvinia molesta D.S. Mitchell (Salviniaceae) in South Africa in 1985. This agent has been highly successful against S. molesta and has significantly reduced the weed’s populations around the country. However, in 2007, the parasitic alga, Helicosporidium sp. (an undescribed species), was detected in field-collected C. salviniae adults in South Africa. The distribution and impacts of this disease on the weevil and its efficacy as a control agent were not known. In this thesis, the prevalence, infection load, and impact of Helicosporidium sp. on C. salviniae was determined. In 2019, adult weevils were collected from 10 sites across the Eastern Cape, KwaZulu-Natal, Limpopo, and Western Cape provinces and screened to determine the occurrence, infection load, and geographic distribution of Helicosporidium sp. Transmission mechanisms of this disease in C. salviniae were then evaluated. The possible impact of Helicosporidium sp. was assessed by comparing the feeding rates and the reproductive output of the diseased and healthy adults of C. salviniae. An attempt was then made to eliminate the disease in C. salviniae through the application of the antibiotic, ketoconazole. Further, the role of temperature on infection load in C. salviniae was also assessed. Finally, recommendations for the long-term biological control programme against S. molesta in South Africa were made. The disease covers the entire distribution range of C. salviniae in South Africa, with the disease occurrence rate ranging from 92.15% to 100% insects infected per site. Helicosporidium sp. was found to transmit vertically within the populations of C. salviniae. Infection by the Helicosporidium sp. disease reduced the reproductive output of C. salviniae as well its impact on biomass reduction of S. molesta when a diseased culture was compared to a healthy culture from the USA. 98.44 to 98.55% of Helicosporidium sp. loads were reduced through multiple applications of ketoconazole concentrations under in vitro trials. In vivo treatments resulted in 70% control of Helicosporidium sp. in the adults of C. salviniae that were fed ketoconazole three times over a 21 day period. Adult C. salviniae feeding and survival performances were similar when fed fronds of S. molesta inoculated with ketoconazole and water. The lowest and highest disease loads of Helicosporidium sp. were recorded when the weevils were reared at 30°C and 14°C, respectively. As expected, the highest impact and reproductive output of C. salviniae were at 30°C. The evaluations discussed in this thesis highlight the role of diseases in biological control agents, and gaps in both the pre-release and post-release monitoring that should integrate screening of diseases in these studies. Although the combined application of the antibiotic and temperature will reduce Helicosporidium sp. loads and impact, this technology is most likely only applicable where the weevils are reared in small numbers in a rearing facility and not really applicable to the field situation. It is important to release healthy agents that will cause efficient control of the target weed plant species, therefore, when introducing new biological control agents, the health status of such agents needs to be understood. Therefore, long-term field monitoring and assessment of the impact of C. salviniae on S. molesta should be conducted to track all the changes that may result due to the presence of Helicosporidium sp. This long-term monitoring and assessment will give a more informative role of Helicosporidium sp. in field populations of C. salviniae. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-10-14
Synthesis, characterization and host-guest complexes of supramolecular assemblies based on calixarenes and cucurbiturils
- Authors: Baa, Ebenezer
- Date: 2022-10-14
- Subjects: Supramolecular chemistry , Calixarenes , Cucurbiturils , Metal-organic frameworks , Macrocyclic compounds , Drug delivery systems
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365621 , vital:65765 , DOI https://doi.org/10.21504/10962/365621
- Description: The field of supramolecular chemistry has grown large and wide in both deepness of understanding, range of topics covered and scope and applications. Supramolecular self-assemblies are facilitated by a wide range of non-covalent intra and inter molecular interactions that range from hydrogen bonding to π-interaction and van der Waals. Macrocyclic compounds such as cucurbiturils and calixarenes have emerged as important classes of compounds with excellent potential of forming supramolecular assemblies. The porous nature of these compounds enables them to form host-guest supramolecular complexes stabilized by diverse range of non-covalent interactions. Furthermore, these compounds contain donor atoms capable of forming bonds with metal ions to yield metal complexes with interesting porous characteristics that deviate from their traditional hydrophobic cavity. The versatile nature of the resulting pores imply that they can accommodate diverse types of guests. This work explores the synthesis and characterization of a host of calixarenes and cucurbiturils. Self-assembly of these macrocycles with various metal ions results to the formation of porous metal organic framework (MOF) complexes. Four new calixarene typed compounds obtained from aromatic aldehydes and twenty-six cucurbituril metal complexes are reported. These macrocylces and their metal complexes also form supramolecular complexes with DMSO, methanol, isoniazid hydrochloride and ciprofloxacin hydrochlorides through either self-assembly, mechanochemistry and exposure to solvent vapors. The bulk materials have been characterized using nuclear magnetic resonance spectroscopy (NMR), Fourier transformed infrared spectroscopy (FTIR), powder and single crystal diffraction techniques and thermal studies thermogravimetric analysis (TGA) and differential thermal calorimetry (DSC). Data obtained from this study reveals that calixarenes can form supramolecular complexes with a frequently used laboratory solvents with BN22 showing appreciable selectivity for DMSO sorption from a solvent mixture. These compounds also form supramolecular complexes with drug molecules such as isoniazid and ciprofloxacin. Furthermore, the data reveals that choice of synthetic route of supramolecular ensembles dictates if the guest drug molecule will occupy the intrinsic or extrinsic pores of cucurbituril complexes. Biological studies on the obtained complexes reveal that the cucurbituril complexes are non-cytotoxic while the calixarenes show antibacterial activity against Escherichia coli and Staphylococcus aureus. Additionally, the study showed that ciprofloxacin can be successfully released from a calixarene host in a simulated body fluid although the host was also found to cross the dialysis membrane. The results of this study are important in that; - they can be exploited and developed in the selective sorption of certain guests and - that they can be used in the development of drug delivery systems that play a dual role of delivery and therapeutic activity. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Baa, Ebenezer
- Date: 2022-10-14
- Subjects: Supramolecular chemistry , Calixarenes , Cucurbiturils , Metal-organic frameworks , Macrocyclic compounds , Drug delivery systems
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365621 , vital:65765 , DOI https://doi.org/10.21504/10962/365621
- Description: The field of supramolecular chemistry has grown large and wide in both deepness of understanding, range of topics covered and scope and applications. Supramolecular self-assemblies are facilitated by a wide range of non-covalent intra and inter molecular interactions that range from hydrogen bonding to π-interaction and van der Waals. Macrocyclic compounds such as cucurbiturils and calixarenes have emerged as important classes of compounds with excellent potential of forming supramolecular assemblies. The porous nature of these compounds enables them to form host-guest supramolecular complexes stabilized by diverse range of non-covalent interactions. Furthermore, these compounds contain donor atoms capable of forming bonds with metal ions to yield metal complexes with interesting porous characteristics that deviate from their traditional hydrophobic cavity. The versatile nature of the resulting pores imply that they can accommodate diverse types of guests. This work explores the synthesis and characterization of a host of calixarenes and cucurbiturils. Self-assembly of these macrocycles with various metal ions results to the formation of porous metal organic framework (MOF) complexes. Four new calixarene typed compounds obtained from aromatic aldehydes and twenty-six cucurbituril metal complexes are reported. These macrocylces and their metal complexes also form supramolecular complexes with DMSO, methanol, isoniazid hydrochloride and ciprofloxacin hydrochlorides through either self-assembly, mechanochemistry and exposure to solvent vapors. The bulk materials have been characterized using nuclear magnetic resonance spectroscopy (NMR), Fourier transformed infrared spectroscopy (FTIR), powder and single crystal diffraction techniques and thermal studies thermogravimetric analysis (TGA) and differential thermal calorimetry (DSC). Data obtained from this study reveals that calixarenes can form supramolecular complexes with a frequently used laboratory solvents with BN22 showing appreciable selectivity for DMSO sorption from a solvent mixture. These compounds also form supramolecular complexes with drug molecules such as isoniazid and ciprofloxacin. Furthermore, the data reveals that choice of synthetic route of supramolecular ensembles dictates if the guest drug molecule will occupy the intrinsic or extrinsic pores of cucurbituril complexes. Biological studies on the obtained complexes reveal that the cucurbituril complexes are non-cytotoxic while the calixarenes show antibacterial activity against Escherichia coli and Staphylococcus aureus. Additionally, the study showed that ciprofloxacin can be successfully released from a calixarene host in a simulated body fluid although the host was also found to cross the dialysis membrane. The results of this study are important in that; - they can be exploited and developed in the selective sorption of certain guests and - that they can be used in the development of drug delivery systems that play a dual role of delivery and therapeutic activity. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-10-14
Viability of government funded broiler production : lessons from Northern KwaZulu Natal, South Africa
- Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Authors: Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Date: 2023-04
- Subjects: Broilers (Chickens) -- Economic aspects , Broilers (Poultry) , Broilers (Chickens) -- Breeding
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27843 , vital:69947
- Description: Generally, rural areas continue to experience high poverty levels and low incomes, which seem to be occasioned by high unemployment rates, limited educational attainments, and devastating floods and droughts. This situation is further exacerbated by increase in crime rates, making livelihoods even more difficult. To mitigate such adverse situations, rural households employ diverse strategies, including maintaining community gardens, one-home-one-garden schemes, as well as livestock and poultry production. The most prevalent livelihood strategy in South Africa or KwaZulu-Natal is broiler production, since it needs less space and a short production cycle compared to other livestock or crop enterprises. At the same time, income is generated over a short period. Besides, the government of KwaZulu Natal has actively intervened in the sector as part of its broader poverty reduction strategy and farmer support programmes. In KwaZulu-Natal Province, the provincial government has been supporting broiler producers for many years. While substantial research work has been done in the province on livelihood strategies, including livestock production on a province-wide basis, there is no information about how successful the broiler production funded by the government has being. Broader concerns about production problems have not been assuaged based on systematic studies and evidence. It is this wise that this study was initiated. The objective is to assess the economic viability of government-funded small-scale broiler projects in the KwaZulu-Natal Province of South Africa and determine the implications for poverty reduction and food security. Data were collected from the government-funded small-scale broiler producers that are residing in Northern KwaZulu-Natal districts uThungulu, Zululand and uMkhanyakude. A total of 75 small-scale broiler projects 25 broiler projects in each district were selected by probability sampling procedure for the interviews. Questionnaires that combined both close-ended and open-ended questions were used to collect primary data, which include production and marketing, as well as the factors that influence the profitability of the small-scale broiler projects. After collection, data were captured and encoded on spreadsheets in Microsoft Excel and exported to Statistical Package for the Social Science (SPSS) software version 26 and STATA for analyses. Descriptive statistics applied include frequencies and means. In addition, a gross margin (GM) and gross profit margin (GPM) analysis were employed to assess the profitability of government-funded small-scale broiler projects. Both profitability and gross margin analyses were used as proxies for farmers’ motivation and incentives to participate in broiler production. Further analyses were conducted to determine the model that best explains the underlying relationships. Initially, the Multiple Linear Regression Model was applied to determine the factors influencing the profitability of government-funded small-scale broiler projects. The indication was that while positive profits were revealed, the system seemed to fall short of its potential. In light of that, it was decided to fit another model to estimate the technical efficiency of the system and gain an understanding of the causes of any inefficiency that might exist in the production system. In that regard, the one-step Stochastic Frontier Model was employed to show that the technical efficiency of broiler production systems in the project area was positively and significantly influenced by flock size, the quantity of feeds and labour costs, while medication played no role possibly because of weak extension coverage. An inefficiency model fitted as part of the one-step model suggested that age, gender and educational level were significant influencers of technical inefficiency, with the possibility that the older the farmers, the more technically inefficient the system possibly because of the strenuousness of commercial poultry production. In addition, it was found that the more educated the farmer, the less inefficient the farm, which conversely means that the system becomes more efficient as the farmer receives more education. The negative coefficient of the gender variable also implies that for farms managed by female farmers, the system was less inefficient, which is more technically efficient, and this can be explained by women’s propensity to be more gentle, caring and sensitive in managing the chickens than their male counterparts. Heteroskedasticity tests and corrections were conducted in the one-step estimation technique to show that variations in the inefficiency term (μ) and the stochastic error term were explained by age and educational level for the most part. Clearly, improvements in the broiler industry in KwaZulu-Natal will depend to a large extent on the knowledge and experience of the farmers and substantial enlargement of the flock size of adequately fed birds. Attention to these elements is expected to have important practical implications for sustainable broiler poultry development and food security in the project area, as well as locations possessing identical features and characteristics. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Date: 2023-04
- Subjects: Broilers (Chickens) -- Economic aspects , Broilers (Poultry) , Broilers (Chickens) -- Breeding
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27843 , vital:69947
- Description: Generally, rural areas continue to experience high poverty levels and low incomes, which seem to be occasioned by high unemployment rates, limited educational attainments, and devastating floods and droughts. This situation is further exacerbated by increase in crime rates, making livelihoods even more difficult. To mitigate such adverse situations, rural households employ diverse strategies, including maintaining community gardens, one-home-one-garden schemes, as well as livestock and poultry production. The most prevalent livelihood strategy in South Africa or KwaZulu-Natal is broiler production, since it needs less space and a short production cycle compared to other livestock or crop enterprises. At the same time, income is generated over a short period. Besides, the government of KwaZulu Natal has actively intervened in the sector as part of its broader poverty reduction strategy and farmer support programmes. In KwaZulu-Natal Province, the provincial government has been supporting broiler producers for many years. While substantial research work has been done in the province on livelihood strategies, including livestock production on a province-wide basis, there is no information about how successful the broiler production funded by the government has being. Broader concerns about production problems have not been assuaged based on systematic studies and evidence. It is this wise that this study was initiated. The objective is to assess the economic viability of government-funded small-scale broiler projects in the KwaZulu-Natal Province of South Africa and determine the implications for poverty reduction and food security. Data were collected from the government-funded small-scale broiler producers that are residing in Northern KwaZulu-Natal districts uThungulu, Zululand and uMkhanyakude. A total of 75 small-scale broiler projects 25 broiler projects in each district were selected by probability sampling procedure for the interviews. Questionnaires that combined both close-ended and open-ended questions were used to collect primary data, which include production and marketing, as well as the factors that influence the profitability of the small-scale broiler projects. After collection, data were captured and encoded on spreadsheets in Microsoft Excel and exported to Statistical Package for the Social Science (SPSS) software version 26 and STATA for analyses. Descriptive statistics applied include frequencies and means. In addition, a gross margin (GM) and gross profit margin (GPM) analysis were employed to assess the profitability of government-funded small-scale broiler projects. Both profitability and gross margin analyses were used as proxies for farmers’ motivation and incentives to participate in broiler production. Further analyses were conducted to determine the model that best explains the underlying relationships. Initially, the Multiple Linear Regression Model was applied to determine the factors influencing the profitability of government-funded small-scale broiler projects. The indication was that while positive profits were revealed, the system seemed to fall short of its potential. In light of that, it was decided to fit another model to estimate the technical efficiency of the system and gain an understanding of the causes of any inefficiency that might exist in the production system. In that regard, the one-step Stochastic Frontier Model was employed to show that the technical efficiency of broiler production systems in the project area was positively and significantly influenced by flock size, the quantity of feeds and labour costs, while medication played no role possibly because of weak extension coverage. An inefficiency model fitted as part of the one-step model suggested that age, gender and educational level were significant influencers of technical inefficiency, with the possibility that the older the farmers, the more technically inefficient the system possibly because of the strenuousness of commercial poultry production. In addition, it was found that the more educated the farmer, the less inefficient the farm, which conversely means that the system becomes more efficient as the farmer receives more education. The negative coefficient of the gender variable also implies that for farms managed by female farmers, the system was less inefficient, which is more technically efficient, and this can be explained by women’s propensity to be more gentle, caring and sensitive in managing the chickens than their male counterparts. Heteroskedasticity tests and corrections were conducted in the one-step estimation technique to show that variations in the inefficiency term (μ) and the stochastic error term were explained by age and educational level for the most part. Clearly, improvements in the broiler industry in KwaZulu-Natal will depend to a large extent on the knowledge and experience of the farmers and substantial enlargement of the flock size of adequately fed birds. Attention to these elements is expected to have important practical implications for sustainable broiler poultry development and food security in the project area, as well as locations possessing identical features and characteristics. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-04
An evaluation of the effectiveness of area-based conservation interventions in avoiding biodiversity loss in South Africa
- Authors: Von Staden, Lize
- Date: 2023-04
- Subjects: Environmental policy , Conservation of natural resources -- Government policy -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61115 , vital:69762
- Description: Counterfactual impact evaluation studies form an important evidence base for the effectiveness of conservation projects, programs, and policies (collectively referred to as conservation interventions). In South Africa, counterfactual impact evaluation methods have rarely been applied to local conservation interventions, and therefore evidence for the effectiveness of key strategic national conservation approaches is lacking. This study evaluated three area-based interventions that together aim to avoid the loss of areas most important for the persistence of biodiversity in the terrestrial realm as evidence towards the effectiveness of South Africa’s landscape approach to biodiversity conservation. The first intervention, South Africa’s National Protected Area Expansion Strategy (NPAES), set ambitious targets to double the extent of South Africa’s protected area network while ensuring that the expansion preferentially occurs in areas of under-represented biodiversity. The strategy was evaluated in terms of its effectiveness in guiding protected area expansion towards more equitable representation of South Africa’s biodiversity through an assessment of changes in indicators of protected area expansion decision-making before and after the implementation of the strategy. The second intervention is the use of maps of biodiversity priorities to guide land use change decisions outside protected areas. Impact was evaluated as avoided loss of Critical Biodiversity Areas (CBAs), which need to remain in a natural condition to meet in situ conservation targets for species, ecosystems, and ecological processes. Avoided loss in CBAs was benchmarked against avoided loss in protected areas, to contextualize the effectiveness of land use planning as a conservation intervention. Lastly, the effectiveness of stricter land use regulations for threatened ecosystems to reduce land conversion pressure on these ecosystems was evaluated. Key findings were that protected areas are highly effective conservation interventions where they can be implemented, but their capacity for conservation impact is limited by severe constraints on strategic expansion. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Von Staden, Lize
- Date: 2023-04
- Subjects: Environmental policy , Conservation of natural resources -- Government policy -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61115 , vital:69762
- Description: Counterfactual impact evaluation studies form an important evidence base for the effectiveness of conservation projects, programs, and policies (collectively referred to as conservation interventions). In South Africa, counterfactual impact evaluation methods have rarely been applied to local conservation interventions, and therefore evidence for the effectiveness of key strategic national conservation approaches is lacking. This study evaluated three area-based interventions that together aim to avoid the loss of areas most important for the persistence of biodiversity in the terrestrial realm as evidence towards the effectiveness of South Africa’s landscape approach to biodiversity conservation. The first intervention, South Africa’s National Protected Area Expansion Strategy (NPAES), set ambitious targets to double the extent of South Africa’s protected area network while ensuring that the expansion preferentially occurs in areas of under-represented biodiversity. The strategy was evaluated in terms of its effectiveness in guiding protected area expansion towards more equitable representation of South Africa’s biodiversity through an assessment of changes in indicators of protected area expansion decision-making before and after the implementation of the strategy. The second intervention is the use of maps of biodiversity priorities to guide land use change decisions outside protected areas. Impact was evaluated as avoided loss of Critical Biodiversity Areas (CBAs), which need to remain in a natural condition to meet in situ conservation targets for species, ecosystems, and ecological processes. Avoided loss in CBAs was benchmarked against avoided loss in protected areas, to contextualize the effectiveness of land use planning as a conservation intervention. Lastly, the effectiveness of stricter land use regulations for threatened ecosystems to reduce land conversion pressure on these ecosystems was evaluated. Key findings were that protected areas are highly effective conservation interventions where they can be implemented, but their capacity for conservation impact is limited by severe constraints on strategic expansion. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-04
Assessment of the human health implications of climate variability in East London, Eastern Cape, South Africa
- Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Authors: Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Date: 2018
- Subjects: Climatic changes http://id.loc.gov/authorities/subjects/sh85027037
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19715 , vital:43171
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03 percent and 0.9 percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period. , Thesis (PhD) (Geography) -- University of Fort Hare, 2018
- Full Text:
- Date Issued: 2018
- Authors: Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Date: 2018
- Subjects: Climatic changes http://id.loc.gov/authorities/subjects/sh85027037
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19715 , vital:43171
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03 percent and 0.9 percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period. , Thesis (PhD) (Geography) -- University of Fort Hare, 2018
- Full Text:
- Date Issued: 2018