Automated machine learning plankton taxonomy pipeline
- Authors: Du Toit, Ian Charles
- Date: 2022-04
- Subjects: machine learning , Plankton -- Ecology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58363 , vital:59003
- Description: Plankton taxonomy is considered a multi-class classification problem. The current state-of-the-art developments in machine learning and phytoplankton taxonomy, such as MorphoCluster, include using a convolutional neural network as a feature extractor and Hierarchical Density-Based Clustering for the classification of plankton and identification of outliers. These convolutional feature extraction algorithms achieved accuracies of 0.78 during the classification process. However, these feature extraction models are trained on clean datasets. They perform very well when analysing previously encountered and well-defined classes but do not perform well when tested on raw datasets expected in field deployment. Raw plankton datasets are unbalanced; whereas some classes only have one or two samples, others can have thousands. They also exhibit many inter-class similarities with significant size differences. The data can also be in the form of low-resolution, noisy images. Phytoplankton species are also highly biodiverse, meaning that there is always a higher chance of a network encountering unknown sample types. Some samples, such as the various body parts of organisms, are easily confused with the species itself. Marine experts classifying plankton tend to group ambiguous samples according to the highest order to which they are confident they belong. This system leads to a dataset containing conflicting classes and forces the feature extraction network to overfit when training. This research aims to address these spatial issues and present a feature extraction methodology built upon existing research and novel concepts. The proposed algorithm uses feature extraction methods designed around real-world sample sets and offers an alternative approach to optimizing the features extracted and supplied to the clustering algorithm. The proposed feature extraction methods achieved scores of 0.821 when tested on the same datasets as the general feature extractor. The algorithm also consists of Auxiliary SoftMax classification branches which indicate the class prediction obtained by the feature extraction models. These branches allow for autonomous labelling of the clusters formed during the HDBSCAN algorithm being performed on the extracted features. This results in a fully automated semi-supervised plankton taxonomy pipeline which achieves a classification score of 0.775 on a real-life sample set. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Du Toit, Ian Charles
- Date: 2022-04
- Subjects: machine learning , Plankton -- Ecology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58363 , vital:59003
- Description: Plankton taxonomy is considered a multi-class classification problem. The current state-of-the-art developments in machine learning and phytoplankton taxonomy, such as MorphoCluster, include using a convolutional neural network as a feature extractor and Hierarchical Density-Based Clustering for the classification of plankton and identification of outliers. These convolutional feature extraction algorithms achieved accuracies of 0.78 during the classification process. However, these feature extraction models are trained on clean datasets. They perform very well when analysing previously encountered and well-defined classes but do not perform well when tested on raw datasets expected in field deployment. Raw plankton datasets are unbalanced; whereas some classes only have one or two samples, others can have thousands. They also exhibit many inter-class similarities with significant size differences. The data can also be in the form of low-resolution, noisy images. Phytoplankton species are also highly biodiverse, meaning that there is always a higher chance of a network encountering unknown sample types. Some samples, such as the various body parts of organisms, are easily confused with the species itself. Marine experts classifying plankton tend to group ambiguous samples according to the highest order to which they are confident they belong. This system leads to a dataset containing conflicting classes and forces the feature extraction network to overfit when training. This research aims to address these spatial issues and present a feature extraction methodology built upon existing research and novel concepts. The proposed algorithm uses feature extraction methods designed around real-world sample sets and offers an alternative approach to optimizing the features extracted and supplied to the clustering algorithm. The proposed feature extraction methods achieved scores of 0.821 when tested on the same datasets as the general feature extractor. The algorithm also consists of Auxiliary SoftMax classification branches which indicate the class prediction obtained by the feature extraction models. These branches allow for autonomous labelling of the clusters formed during the HDBSCAN algorithm being performed on the extracted features. This results in a fully automated semi-supervised plankton taxonomy pipeline which achieves a classification score of 0.775 on a real-life sample set. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
The criminal liability of health care practitioners for culpable homicide
- Authors: Dweba, Asavela
- Date: 2022-04
- Subjects: South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55511 , vital:52594
- Description: South African health societies and associations have allied to call for reform in the criminal law system involving the prosecution of health care practitioners, specifically on charges of culpable homicide. Warranted by the spate of criminal prosecutions against healthcare practitioners and the need for reform, this treatise investigates the criminal liability of healthcare practitioners for culpable homicide. Overall, this study aims to determine the recognition of criminal liability of healthcare practitioners, requirements for culpability, the level of negligence that constitutes culpable homicide, and whether the South African law can adjust the threshold for criminal liability in culpable homicide. An analysis of the consequences of legal literature concerning the offence of culpable homicide and medical negligence is provided. In addition, this study examines pertinent case law to devise a strategy for law reform in South Africa and the development of common law. The study includes a comparative study of foreign jurisdictions to incorporate the position in England, Scotland, New Zealand, India, and Canada from which South Africa can adopt some principles within the South African context. The analysis revealed that South Africa has a low threshold in the form of ordinary negligence required to establish criminal liability in cases of culpable homicide while a higher threshold is required for the selected foreign jurisdictions. Furthermore, this treatise contends that the current South African criminal justice regime is lacking in identifying the ideal degree of fault required for criminal conduct. Thus, reform of South Africa’s approach in dealing with healthcare practitioners suspected/ accused of causing the death of patients under medical care is necessary. This study recommends that the South African criminal law justice system should be developed by way of legislative intervention in which ‘gross negligence or recklessness’ will serve as a measure to criminalise the conduct of healthcare practitioners. This study acknowledges the noble role played by healthcare practitioners in the society and notes that medicine is not an exact science. Therefore, this treatise does not advocate a mandatory exoneration of criminal liability of healthcare practitioners. Rather, for a fair and evidence-based prosecution of reckless medical practices. , Thesis (LLM) -- Faculty of Law, Department of Criminal and Procedural Law, 2021
- Full Text:
- Date Issued: 2022-04
- Authors: Dweba, Asavela
- Date: 2022-04
- Subjects: South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55511 , vital:52594
- Description: South African health societies and associations have allied to call for reform in the criminal law system involving the prosecution of health care practitioners, specifically on charges of culpable homicide. Warranted by the spate of criminal prosecutions against healthcare practitioners and the need for reform, this treatise investigates the criminal liability of healthcare practitioners for culpable homicide. Overall, this study aims to determine the recognition of criminal liability of healthcare practitioners, requirements for culpability, the level of negligence that constitutes culpable homicide, and whether the South African law can adjust the threshold for criminal liability in culpable homicide. An analysis of the consequences of legal literature concerning the offence of culpable homicide and medical negligence is provided. In addition, this study examines pertinent case law to devise a strategy for law reform in South Africa and the development of common law. The study includes a comparative study of foreign jurisdictions to incorporate the position in England, Scotland, New Zealand, India, and Canada from which South Africa can adopt some principles within the South African context. The analysis revealed that South Africa has a low threshold in the form of ordinary negligence required to establish criminal liability in cases of culpable homicide while a higher threshold is required for the selected foreign jurisdictions. Furthermore, this treatise contends that the current South African criminal justice regime is lacking in identifying the ideal degree of fault required for criminal conduct. Thus, reform of South Africa’s approach in dealing with healthcare practitioners suspected/ accused of causing the death of patients under medical care is necessary. This study recommends that the South African criminal law justice system should be developed by way of legislative intervention in which ‘gross negligence or recklessness’ will serve as a measure to criminalise the conduct of healthcare practitioners. This study acknowledges the noble role played by healthcare practitioners in the society and notes that medicine is not an exact science. Therefore, this treatise does not advocate a mandatory exoneration of criminal liability of healthcare practitioners. Rather, for a fair and evidence-based prosecution of reckless medical practices. , Thesis (LLM) -- Faculty of Law, Department of Criminal and Procedural Law, 2021
- Full Text:
- Date Issued: 2022-04
Bootstrap-based tolerance intervals for nested two-way random effects models
- Authors: Erasmus, Christopher Daniel
- Date: 2022-04
- Subjects: Mathematical statistics-South Africa , Multilevel models
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55573 , vital:53331
- Description: Variance component, or random effects, models are frequently used by manufacturers to model the variance present in a manufacturing process. By applying tolerance intervals to variance component models, manufacturers are able to set upper and lower limits to monitor the variance within a process. Existing methods for constructing tolerance intervals are constrained by the necessity for data to be normally distributed. Recently, non-parametric bootstrap-based methods were developed by Deyzel (2018) to obtain α-expectation and (α, β) two-sided tolerance intervals for the two-way nested random effects model. Classical and non-parametric methods for obtaining tolerance intervals for the one way random effects model have been assessed in accordance with Rebafka et al. (2007). The present study assesses and compares classical, Bayesian and non-parametric methods for obtaining tolerance intervals for the two-way nested random effects model under different assumptions of the underlying distribution. Results show that the non-parametric methods provided relatively narrow intervals, and generally retain the nominal content and guarantee levels, regardless of the underlying distribution , Thesis (MSc) -- Faculty of Science, Mathematical Statistics , 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Erasmus, Christopher Daniel
- Date: 2022-04
- Subjects: Mathematical statistics-South Africa , Multilevel models
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55573 , vital:53331
- Description: Variance component, or random effects, models are frequently used by manufacturers to model the variance present in a manufacturing process. By applying tolerance intervals to variance component models, manufacturers are able to set upper and lower limits to monitor the variance within a process. Existing methods for constructing tolerance intervals are constrained by the necessity for data to be normally distributed. Recently, non-parametric bootstrap-based methods were developed by Deyzel (2018) to obtain α-expectation and (α, β) two-sided tolerance intervals for the two-way nested random effects model. Classical and non-parametric methods for obtaining tolerance intervals for the one way random effects model have been assessed in accordance with Rebafka et al. (2007). The present study assesses and compares classical, Bayesian and non-parametric methods for obtaining tolerance intervals for the two-way nested random effects model under different assumptions of the underlying distribution. Results show that the non-parametric methods provided relatively narrow intervals, and generally retain the nominal content and guarantee levels, regardless of the underlying distribution , Thesis (MSc) -- Faculty of Science, Mathematical Statistics , 2022
- Full Text:
- Date Issued: 2022-04
Perceptions of Role Players in the Pharmaceutical Manufacturing Sector in South Africa Regarding the Proposal of a National Health Insurance System
- Authors: Essex, Laycan
- Date: 2022-04
- Subjects: Pharmaceutical industry -- South Africa , National Health Insurance
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58849 , vital:60218
- Description: The proposed implementation of National Health Insurance (NHI) is attracting considerable interest among healthcare workers, as observed in the large quantity of available literary evidence. The available research is mainly focused on the perceptions of healthcare workers, working under the proposed NHI reform. Based on a literature gap observed in recently published articles on perceptions of healthcare professionals regarding the implementation of NHI, the researcher aimed to assess the opinions of key stakeholders in the pharmaceutical manufacturing sector in South Africa. This study employed a qualitative approach, using semi-structured interviews with key stakeholders employed in the pharmaceutical manufacturing sector. Their perceptions regarding the NHI were analysed and interpreted through thematic analysis in order to determine whether they have a positive or a negative perception towards the introduction of the NHI reform in South Africa. The majority of role players are in full support of NHI and there was a consensus amongst the participants that there will be great opportunities for the pharmaceutical manufacturing sector. Regarding the capabilities relating to capacity to supply, participants felt that South Africa’s pharmaceutical manufacturing sector has sufficient infrastructure to support the roll out of the NHI. Furthermore, participants felt positive about increased accessibility to pharmaceutical care by all South Africans, regardless of race, social and economic status. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Essex, Laycan
- Date: 2022-04
- Subjects: Pharmaceutical industry -- South Africa , National Health Insurance
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58849 , vital:60218
- Description: The proposed implementation of National Health Insurance (NHI) is attracting considerable interest among healthcare workers, as observed in the large quantity of available literary evidence. The available research is mainly focused on the perceptions of healthcare workers, working under the proposed NHI reform. Based on a literature gap observed in recently published articles on perceptions of healthcare professionals regarding the implementation of NHI, the researcher aimed to assess the opinions of key stakeholders in the pharmaceutical manufacturing sector in South Africa. This study employed a qualitative approach, using semi-structured interviews with key stakeholders employed in the pharmaceutical manufacturing sector. Their perceptions regarding the NHI were analysed and interpreted through thematic analysis in order to determine whether they have a positive or a negative perception towards the introduction of the NHI reform in South Africa. The majority of role players are in full support of NHI and there was a consensus amongst the participants that there will be great opportunities for the pharmaceutical manufacturing sector. Regarding the capabilities relating to capacity to supply, participants felt that South Africa’s pharmaceutical manufacturing sector has sufficient infrastructure to support the roll out of the NHI. Furthermore, participants felt positive about increased accessibility to pharmaceutical care by all South Africans, regardless of race, social and economic status. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
State Antiquity and Early Agricultural transition as Deep economic roots in Africa
- Authors: Fani, Sisipho
- Date: 2022-04
- Subjects: Agriculture -- Economic aspects , Agriculture -- Early works to 1800
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57643 , vital:58189
- Description: Growth economists identified that current failures and successes of economies can be traced far in their histories. The Unified Growth Model has been developed to analyse the process of development. Economic researchers have developed and identified ‘deep roots’ variables that elaborate modern growth, institutions and development. These variables include State Antiquity and Early agricultural transition. The study is an examination of the effects of State Antiquity and Early agricultural transition in the 54 African economies. The study examines these effects employing the following years: 1990, 1995, 2000, 2005, 2010, 2015, and 2020. The study employs econometric models namely, Ordinary Least Squares, Ridge and Lasso regularization models to examine the effects of these deep root variables. The study borrows baseline regressions from the works of Bockstette, Chanda and Putterman (2002), Putterman and Weil (2010) and Borcan, Olsson and Putterman (2018). This study, to the best of our knowledge, is the first to empirically examine the effects of State Antiquity and Early agricultural transition in Africa. The results of the study suggest that African economies that have low level of state antiquity experience a positive effect on modern economic growth and development whilst African economies with high levels of state antiquity experience negative effect on modern economic growth and development. The results also suggest that African economies that transition at a later stage toward agriculture experience a positive effect on modern economic growth and development. The implications of these findings indicate that state antiquity and early agricultural transition influence modern economic development only when states have reached a certain level. Countries that transitioned early towards agriculture experience a negative effect on modern economic growth and development depicting a reversal of fortune. The study recommends that the implementation of polices should corelate with the state experience of the specific economy. , Thesis (MA) -- Faculty of Business and Economic science , 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Fani, Sisipho
- Date: 2022-04
- Subjects: Agriculture -- Economic aspects , Agriculture -- Early works to 1800
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57643 , vital:58189
- Description: Growth economists identified that current failures and successes of economies can be traced far in their histories. The Unified Growth Model has been developed to analyse the process of development. Economic researchers have developed and identified ‘deep roots’ variables that elaborate modern growth, institutions and development. These variables include State Antiquity and Early agricultural transition. The study is an examination of the effects of State Antiquity and Early agricultural transition in the 54 African economies. The study examines these effects employing the following years: 1990, 1995, 2000, 2005, 2010, 2015, and 2020. The study employs econometric models namely, Ordinary Least Squares, Ridge and Lasso regularization models to examine the effects of these deep root variables. The study borrows baseline regressions from the works of Bockstette, Chanda and Putterman (2002), Putterman and Weil (2010) and Borcan, Olsson and Putterman (2018). This study, to the best of our knowledge, is the first to empirically examine the effects of State Antiquity and Early agricultural transition in Africa. The results of the study suggest that African economies that have low level of state antiquity experience a positive effect on modern economic growth and development whilst African economies with high levels of state antiquity experience negative effect on modern economic growth and development. The results also suggest that African economies that transition at a later stage toward agriculture experience a positive effect on modern economic growth and development. The implications of these findings indicate that state antiquity and early agricultural transition influence modern economic development only when states have reached a certain level. Countries that transitioned early towards agriculture experience a negative effect on modern economic growth and development depicting a reversal of fortune. The study recommends that the implementation of polices should corelate with the state experience of the specific economy. , Thesis (MA) -- Faculty of Business and Economic science , 2022
- Full Text:
- Date Issued: 2022-04
I want him to hold me, but I’m afraid to ask: the objective correlative and the souvenir as representational narrative devices of queer male intimacy
- Authors: Ferreira, Evaan Jason
- Date: 2022-04
- Subjects: Sexual minorities in art , Sexual minority culture , Intimacy (Psychology) , Sexual minorities in motion pictures , Intimacy (Psychology) in motion pictures , Homosexuality and motion pictures , Motion pictures Study and teaching , New media art , Nostalgia , Souvenirs (Keepsakes) , Gay men , Queer male intimacy , Objective correlative
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232556 , vital:50002
- Description: This thesis centres itself around an investigation into the representations of the relationship between intimacies and ideas of romance, love, desire, and vulnerability in male relationships. The premise for this body of work was sparked by my own observations on the conflation of sex and intimacy in representations of queer male love—particularly (but not exclusively) in mainstream film and media. Whilst intimacy and sex are not unrelated, the over-emphasis on the physical when trying to represent the connection between two men led me to consider other ways in which a relationship or special connection could be gestured towards — through other kinds of signifiers that last longer than physical contact and point to the importance of a particular connection. In the introduction, I consider my own experiences as a closeted queer teen when contemplating representations of queer relationships in mainstream media. I explore several studies by gender and film theorists who consider reasons and modes in which the representations of queer intimacies on-screen are distorted to favour a presumed heterosexual audience. In the first chapter, I discuss two potential means by which to relay a more complex emotional state via the use of narrative signifiers. I examine T.S. Eliot's (1919) theory on the objective correlative in narratives as a means to explore the emotional state of a character through metaphors which open up the reading rather than illustrating it through dialogue or direct speech. I then explore Susan Stewart's (1992) ideas on souvenirs of personal experience. In Chapter Two, I conduct a close reading of three mainstream films, which employ such signifiers in the attempt to share more complex representations of queer male intimacies through well-developed storylines and characters. The films Brokeback Mountain (2006), Moonlight (2016), and Call Me by Your Name (2017) have been selected based on their use of the objective correlative and souvenirs as plot devices (rather than exclusively physical intimacy) to demonstrate the emotional resonance between characters. The third and final chapter explores my own use of objective correlatives and souvenirs as symbolic, narrative devices in my practical body of work: an online garden of remembrance. My practical work focuses largely on the process of creation of these intimacy objects (the objective correlative or the souvenir) through an investigation into my own poetry, which details my experiences of intimacies with other men, specifically where vulnerability and secrecy played a large role. , Thesis (MFA) -- Faculty of Humanities, Fine Arts, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ferreira, Evaan Jason
- Date: 2022-04
- Subjects: Sexual minorities in art , Sexual minority culture , Intimacy (Psychology) , Sexual minorities in motion pictures , Intimacy (Psychology) in motion pictures , Homosexuality and motion pictures , Motion pictures Study and teaching , New media art , Nostalgia , Souvenirs (Keepsakes) , Gay men , Queer male intimacy , Objective correlative
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232556 , vital:50002
- Description: This thesis centres itself around an investigation into the representations of the relationship between intimacies and ideas of romance, love, desire, and vulnerability in male relationships. The premise for this body of work was sparked by my own observations on the conflation of sex and intimacy in representations of queer male love—particularly (but not exclusively) in mainstream film and media. Whilst intimacy and sex are not unrelated, the over-emphasis on the physical when trying to represent the connection between two men led me to consider other ways in which a relationship or special connection could be gestured towards — through other kinds of signifiers that last longer than physical contact and point to the importance of a particular connection. In the introduction, I consider my own experiences as a closeted queer teen when contemplating representations of queer relationships in mainstream media. I explore several studies by gender and film theorists who consider reasons and modes in which the representations of queer intimacies on-screen are distorted to favour a presumed heterosexual audience. In the first chapter, I discuss two potential means by which to relay a more complex emotional state via the use of narrative signifiers. I examine T.S. Eliot's (1919) theory on the objective correlative in narratives as a means to explore the emotional state of a character through metaphors which open up the reading rather than illustrating it through dialogue or direct speech. I then explore Susan Stewart's (1992) ideas on souvenirs of personal experience. In Chapter Two, I conduct a close reading of three mainstream films, which employ such signifiers in the attempt to share more complex representations of queer male intimacies through well-developed storylines and characters. The films Brokeback Mountain (2006), Moonlight (2016), and Call Me by Your Name (2017) have been selected based on their use of the objective correlative and souvenirs as plot devices (rather than exclusively physical intimacy) to demonstrate the emotional resonance between characters. The third and final chapter explores my own use of objective correlatives and souvenirs as symbolic, narrative devices in my practical body of work: an online garden of remembrance. My practical work focuses largely on the process of creation of these intimacy objects (the objective correlative or the souvenir) through an investigation into my own poetry, which details my experiences of intimacies with other men, specifically where vulnerability and secrecy played a large role. , Thesis (MFA) -- Faculty of Humanities, Fine Arts, 2022
- Full Text:
- Date Issued: 2022-04
The Effects of Alcohol and Sunstance Abuse on Productivity in the Sundays River Valley Citrus Industry
- Authors: Fick, Gerard Hendrik
- Date: 2022-04
- Subjects: Substance abuse , Citrus fruit industry , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57654 , vital:58191
- Description: COVID-19 has created a new world to conduct business and few industries were fortunate enough to continue to operate as essential services throughout the pandemic. The South African Citrus Industry was one of these industries. During this pandemic, certain amenities were regarded as dangerous and potentially a contributor to the spread of the COVID-19 virus. Alcohol was deemed one of these contributors. During the lockdown regulations implemented in March of 2020, the Sundays River Valley Citrus Industry noticed certain interesting developments concerning labour and productivity. Initial review of the effects of alcohol and substance abuse on the productivity of citrus workers, revealed limited research into the broader South African Citrus Industry, with more focus on the Western Cape and related wine farms. The aim of this research study is to identify the impact of alcohol and substance abuse on productivity within the Sundays River Valley Citrus Industry. Specifically focusing on absenteeism, workers injuries on duty and workplace incidents pertaining to disciplinary processes. The research further aims to add a monetary value to the implication of these events on the Sundays River Valley Citrus Industry and the possible management strategies involved to remediate the potential affects thereof. This study uses the phenomenological and case study research approaches focusing on the workplace of the researcher within the Sundays River Valley Citrus Industry. Using qualitative content analysis during the interview process, the themes and findings were evaluated alongside the research questions and was found to be in agreement with the views flowing from the research data. The analysis further revealed that Sundays River Valley Citrus Industry is in need of adequate management strategies due to the seasonal nature of the industry to improve labourer job satisfaction and in turn productivity and efficiency. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Fick, Gerard Hendrik
- Date: 2022-04
- Subjects: Substance abuse , Citrus fruit industry , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57654 , vital:58191
- Description: COVID-19 has created a new world to conduct business and few industries were fortunate enough to continue to operate as essential services throughout the pandemic. The South African Citrus Industry was one of these industries. During this pandemic, certain amenities were regarded as dangerous and potentially a contributor to the spread of the COVID-19 virus. Alcohol was deemed one of these contributors. During the lockdown regulations implemented in March of 2020, the Sundays River Valley Citrus Industry noticed certain interesting developments concerning labour and productivity. Initial review of the effects of alcohol and substance abuse on the productivity of citrus workers, revealed limited research into the broader South African Citrus Industry, with more focus on the Western Cape and related wine farms. The aim of this research study is to identify the impact of alcohol and substance abuse on productivity within the Sundays River Valley Citrus Industry. Specifically focusing on absenteeism, workers injuries on duty and workplace incidents pertaining to disciplinary processes. The research further aims to add a monetary value to the implication of these events on the Sundays River Valley Citrus Industry and the possible management strategies involved to remediate the potential affects thereof. This study uses the phenomenological and case study research approaches focusing on the workplace of the researcher within the Sundays River Valley Citrus Industry. Using qualitative content analysis during the interview process, the themes and findings were evaluated alongside the research questions and was found to be in agreement with the views flowing from the research data. The analysis further revealed that Sundays River Valley Citrus Industry is in need of adequate management strategies due to the seasonal nature of the industry to improve labourer job satisfaction and in turn productivity and efficiency. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
The Impact of socio-Economic and institutional factors on the Livelihoods of artisanal fisherfolk of Korsten, Gqeberha.
- Authors: Forbes-Liberty,Abigail
- Date: 2022-04
- Subjects: Fishing--Social aspects -- South Africa , Korsten-- Gqeberha
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55584 , vital:53334
- Description: his dissertation focuses on a relatively underrepresented group of the fishing industry: subsistence fisherfolk. By using a Sustainable Livelihoods Approach (SLA) and Community Capitals Framework (CCF) as a theoretical framework and interpretive lens, the purpose of this qualitative study is to explore the impact of socio-economic and institutional factors on the livelihoods of artisanal fisherfolk of Korsten, Gqeberha (formerly known as Port Elizabeth). By highlighting the socio-spatial implications of the forced removals of the past, this dissertation shows that legislative reforms should consider the population that they affect. Food security is a major issue on a global scale and South Africa is not impervious to food security concerns. This dissertation focuses on the negative impact that socio-economic climate and legislation has had on subsistence fisherfolk. Hunger and poverty eradication is one of the key goals of sustainable development. In this case, subsistence fishers faced legislative reforms at two distinct points in its tumultuous past, both of which had a detrimental impact on this sector of society's ability to support a healthy livelihood. This research fills a theoretical and practical gap in research regarding the current livelihoods, policies, and laws, as well as provides a deeper understanding of the socio-economic context of the subsistence fishing community of Korsten, Gqeberha. The SLA and CCF helps readers understand how subsistence fishers contribute to local livelihoods and integrate into the greater processes of the community. Further, exploration of the institutional policies limiting subsistence fishers helps understand decision making processes and laws in artisanal fisheries and the implications thereof. A snowball sampling method was used to recruit and enrol participants for this study. The sample size consisted of fourteen (14) participants consisting of eight (8) subsistence fishers and six (6) relatives of subsistence fisherfolk. Narrative analysis is a qualitative method that was conducted in this study. Participant observation and semi-structured interviews were conducted as the methods of data collection and analysed in ATLAS.ti 9 Qualitative Analysis Software. Most participants indicated that fishing plays an integral part of their lives. It contributes to and still ensures the food security in the families of Korsten. In addition, participants highlighted the constant legislative and socio-economic barriers as well as the social and personal benefits of fishing in the community. A key recommendation is made for policy-makers to be cognizant of subsistence fishers and to include this underrepresented group in decision making processes. , Thesis (MSc) -- Faculty of Science, Geosciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Forbes-Liberty,Abigail
- Date: 2022-04
- Subjects: Fishing--Social aspects -- South Africa , Korsten-- Gqeberha
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55584 , vital:53334
- Description: his dissertation focuses on a relatively underrepresented group of the fishing industry: subsistence fisherfolk. By using a Sustainable Livelihoods Approach (SLA) and Community Capitals Framework (CCF) as a theoretical framework and interpretive lens, the purpose of this qualitative study is to explore the impact of socio-economic and institutional factors on the livelihoods of artisanal fisherfolk of Korsten, Gqeberha (formerly known as Port Elizabeth). By highlighting the socio-spatial implications of the forced removals of the past, this dissertation shows that legislative reforms should consider the population that they affect. Food security is a major issue on a global scale and South Africa is not impervious to food security concerns. This dissertation focuses on the negative impact that socio-economic climate and legislation has had on subsistence fisherfolk. Hunger and poverty eradication is one of the key goals of sustainable development. In this case, subsistence fishers faced legislative reforms at two distinct points in its tumultuous past, both of which had a detrimental impact on this sector of society's ability to support a healthy livelihood. This research fills a theoretical and practical gap in research regarding the current livelihoods, policies, and laws, as well as provides a deeper understanding of the socio-economic context of the subsistence fishing community of Korsten, Gqeberha. The SLA and CCF helps readers understand how subsistence fishers contribute to local livelihoods and integrate into the greater processes of the community. Further, exploration of the institutional policies limiting subsistence fishers helps understand decision making processes and laws in artisanal fisheries and the implications thereof. A snowball sampling method was used to recruit and enrol participants for this study. The sample size consisted of fourteen (14) participants consisting of eight (8) subsistence fishers and six (6) relatives of subsistence fisherfolk. Narrative analysis is a qualitative method that was conducted in this study. Participant observation and semi-structured interviews were conducted as the methods of data collection and analysed in ATLAS.ti 9 Qualitative Analysis Software. Most participants indicated that fishing plays an integral part of their lives. It contributes to and still ensures the food security in the families of Korsten. In addition, participants highlighted the constant legislative and socio-economic barriers as well as the social and personal benefits of fishing in the community. A key recommendation is made for policy-makers to be cognizant of subsistence fishers and to include this underrepresented group in decision making processes. , Thesis (MSc) -- Faculty of Science, Geosciences, 2022
- Full Text:
- Date Issued: 2022-04
Hook, Line, and Sinker: Fishing in the Online Relationship Realm, an Exploration of Addictiveness in Online Romantic Relationships
- Authors: Froneman, Carmen Michelle
- Date: 2022-04
- Subjects: Online dating , Relationship addiction
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58871 , vital:60229
- Description: In an online space where individuals are meeting and creating relationships, it is important to explore and understand the nuanced, complex psychological phenomena that occur. Current psychological research into the phenomena of online addictiveness has gained traction with international studies exploring and expanding on this phenomena. Definitions of internet addiction differ widely, but research indicates that addicts expend large amounts of time online and that using the internet becomes a significant part of their everyday lives. Consequently, exploring individual’s experiences of online addiction within a romantic context becomes more relevant. The aim of this study was to explore and describe adults lived experiences of addictiveness in the context of online romantic relationships by expanding on the previous data of Froneman’s (2016) study. The present study utilised a qualitative approach and was exploratory and descriptive in design. The sample size of the present study was seven adult participants and semi-structured interviews were utilised as the method of data collection. Themes including motivation for using online dating, spending time online and the Biopsychosocial dynamics were identified through the participant’s narratives. These findings ultimately can be used for future research. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Froneman, Carmen Michelle
- Date: 2022-04
- Subjects: Online dating , Relationship addiction
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58871 , vital:60229
- Description: In an online space where individuals are meeting and creating relationships, it is important to explore and understand the nuanced, complex psychological phenomena that occur. Current psychological research into the phenomena of online addictiveness has gained traction with international studies exploring and expanding on this phenomena. Definitions of internet addiction differ widely, but research indicates that addicts expend large amounts of time online and that using the internet becomes a significant part of their everyday lives. Consequently, exploring individual’s experiences of online addiction within a romantic context becomes more relevant. The aim of this study was to explore and describe adults lived experiences of addictiveness in the context of online romantic relationships by expanding on the previous data of Froneman’s (2016) study. The present study utilised a qualitative approach and was exploratory and descriptive in design. The sample size of the present study was seven adult participants and semi-structured interviews were utilised as the method of data collection. Themes including motivation for using online dating, spending time online and the Biopsychosocial dynamics were identified through the participant’s narratives. These findings ultimately can be used for future research. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
The contribution of international financial institutions to economic development in SADC countries
- Authors: Galaga, Unathi
- Date: 2022-04
- Subjects: Economic development , Financial institutions, International , Southern African Development Community
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57665 , vital:58193
- Description: Although African governments have a significant role to perform in developing the continent, International financial institutions (IFIs) also perform a dominant role in economic development but their role in African development is often viewed as controversial and contradictory. In the 20th century, the World Bank and the IMF were vital IFIs that characterised global policies that regulated global economies, subjecting weaker economies to SAP. This necessitated African states to borrow money to ensure stabilisation, liberalisation, deregulation and the privatisation of most sectors. This study econometrically examined the impact of foreign aid on economic development in SADC countries. Panel regression techniques were employed to analyse the contribution of international financial institutions to economic development in SADC countries. The results indicated that there is an insignificant relationship between foreign aid and economic development, which implies that foreign aid does not contribute to economic development in SADC countries. Based on this finding, the study recommends that Southern African Governments find ways of financing development that guarantee economic growth. , Thesis (MA) -- Faculty of Business and Economic science , 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Galaga, Unathi
- Date: 2022-04
- Subjects: Economic development , Financial institutions, International , Southern African Development Community
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57665 , vital:58193
- Description: Although African governments have a significant role to perform in developing the continent, International financial institutions (IFIs) also perform a dominant role in economic development but their role in African development is often viewed as controversial and contradictory. In the 20th century, the World Bank and the IMF were vital IFIs that characterised global policies that regulated global economies, subjecting weaker economies to SAP. This necessitated African states to borrow money to ensure stabilisation, liberalisation, deregulation and the privatisation of most sectors. This study econometrically examined the impact of foreign aid on economic development in SADC countries. Panel regression techniques were employed to analyse the contribution of international financial institutions to economic development in SADC countries. The results indicated that there is an insignificant relationship between foreign aid and economic development, which implies that foreign aid does not contribute to economic development in SADC countries. Based on this finding, the study recommends that Southern African Governments find ways of financing development that guarantee economic growth. , Thesis (MA) -- Faculty of Business and Economic science , 2022
- Full Text:
- Date Issued: 2022-04
Ifuthe leelwimi kwimpumelelo yabafundi bebanga leshumi elinambini kwizifundo zejiyografi(sezelizwe) kwizikolo ezibini ezichongiweyo kwisithili saseMonti
- Authors: Gcaki, Nomnqakati
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55342 , vital:51915
- Description: Isahluko sokuqala sixoxa ngengxaki yophando esi siseko kolu phando, nemibuzo yophando kunye neenjongo zokuba isifundo esikhoyo sifuna ukufezekisa ntoni. Ngokunxulumene nengxaki ephandwayo, esi sahluko sigxile kuphononongo loncwadi ukuze kuhlolwe ubudlelwane phakathi kolwimi lokufundisa kunye nempumelelo yabafundi kwiBanga le-12 kwisifundo seJiyografi. Ukuhlolwa koncwadi kuthathwe kwimigaqo-nkqubo yokufundisa kunye neethiyori zophuhliso lokuqonda nenkcubeko. Inkqubo yeethiyori ezikhethiweyo zisetyenziselwa ukwenza ingqiqo yokuba ulwimi lokufundisa luba nefuthe njani ekufundiseni nasekukhuleni kwengqondo nokuqiqa komfundi. Ngophononongo loncwadi, umphandi unqwenela ukufumanisa ubunzima abahlangabezana nabo abafundi ekufundeni iJiyografi ngolwimi lwesiNgesi kwiBanga leshumi elinesibini. Olu phando luza kuphonononga nzulu ifuthe leelwimi kwimpumelelo yabafundi kwisifundo seJiyografi kubafundi besigaba seshumi elinambini kujoliswe kwindlela abaphumelela ngayo kwiimviwo zokuphela konyaka.Olu phando luza kujongwa kwizikolo ezibini kwiphondo leMpuma Koloni kwisithili saseMonti phakathi kweminyaka wama-2016 ukuya kuma-2018.Ngokophando esele lwenziwe, abafundi abalwimi lwabo lwasekhaya lusisiXhosa kufanele ukuba bafundiswa ngolwimi lwabo abazikhethele lona ukutsho oko isiXhosa kwaye bavavanywe kwangalo. Oku akunjalo njengoko amaphepha abo ovavanyo engolwimi lwesiNgesi, lwimi olo olufika lubabeke phantsi konxinzelelo olukhulu olubenza bangabinakho ukuzithemba nokuziva bekhululekile xa bephendula imibuzo emagumbini okufundela. Umphandi olu luvo uluseka ngengxelo ayifumene kumaxwebhu eSebe lezeMfundo (2018 NSC Chief Markers Report) yesifundo seJiyografi iphepha lokuqala. , Thesis (MA) -- Faculty of Humanities, School of Language, Media and Communication, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Gcaki, Nomnqakati
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55342 , vital:51915
- Description: Isahluko sokuqala sixoxa ngengxaki yophando esi siseko kolu phando, nemibuzo yophando kunye neenjongo zokuba isifundo esikhoyo sifuna ukufezekisa ntoni. Ngokunxulumene nengxaki ephandwayo, esi sahluko sigxile kuphononongo loncwadi ukuze kuhlolwe ubudlelwane phakathi kolwimi lokufundisa kunye nempumelelo yabafundi kwiBanga le-12 kwisifundo seJiyografi. Ukuhlolwa koncwadi kuthathwe kwimigaqo-nkqubo yokufundisa kunye neethiyori zophuhliso lokuqonda nenkcubeko. Inkqubo yeethiyori ezikhethiweyo zisetyenziselwa ukwenza ingqiqo yokuba ulwimi lokufundisa luba nefuthe njani ekufundiseni nasekukhuleni kwengqondo nokuqiqa komfundi. Ngophononongo loncwadi, umphandi unqwenela ukufumanisa ubunzima abahlangabezana nabo abafundi ekufundeni iJiyografi ngolwimi lwesiNgesi kwiBanga leshumi elinesibini. Olu phando luza kuphonononga nzulu ifuthe leelwimi kwimpumelelo yabafundi kwisifundo seJiyografi kubafundi besigaba seshumi elinambini kujoliswe kwindlela abaphumelela ngayo kwiimviwo zokuphela konyaka.Olu phando luza kujongwa kwizikolo ezibini kwiphondo leMpuma Koloni kwisithili saseMonti phakathi kweminyaka wama-2016 ukuya kuma-2018.Ngokophando esele lwenziwe, abafundi abalwimi lwabo lwasekhaya lusisiXhosa kufanele ukuba bafundiswa ngolwimi lwabo abazikhethele lona ukutsho oko isiXhosa kwaye bavavanywe kwangalo. Oku akunjalo njengoko amaphepha abo ovavanyo engolwimi lwesiNgesi, lwimi olo olufika lubabeke phantsi konxinzelelo olukhulu olubenza bangabinakho ukuzithemba nokuziva bekhululekile xa bephendula imibuzo emagumbini okufundela. Umphandi olu luvo uluseka ngengxelo ayifumene kumaxwebhu eSebe lezeMfundo (2018 NSC Chief Markers Report) yesifundo seJiyografi iphepha lokuqala. , Thesis (MA) -- Faculty of Humanities, School of Language, Media and Communication, 2022
- Full Text:
- Date Issued: 2022-04
Effect of fire severity on Afrotemperate forest tree survival
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55385 , vital:51988
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broadleaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text: false
- Date Issued: 2022-04
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55385 , vital:51988
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broadleaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text: false
- Date Issued: 2022-04
Effect of fire severity on Afrotemperate forest tree survival
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Trees -- Mortality , Wildfires
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57413 , vital:57635
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broad-leaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity vi facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Trees -- Mortality , Wildfires
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57413 , vital:57635
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broad-leaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity vi facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, 2022
- Full Text:
- Date Issued: 2022-04
Functional biogeography: evaluating community assemblage patterns and ecosystem functioning in intertidal systems using trait-based approaches
- Authors: Gusha, Molline Natanah C
- Date: 2022-10-14
- Subjects: Biogeography , Marine algae , Benthic ecology , Invertebrates , Functional redundancy , Ocean temperature , Biology Classification
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365792 , vital:65790 , DOI https://doi.org/10.21504/10962/365792
- Description: Analyses of taxonomic diversity patterns within coastal systems has been critical in the development of the theory of biogeography. Increasing evidence, however, shows that the variety of functions that species perform in ecosystems (rather than their taxonomic identity) is a better predictor of the influence of the environment on the species. This information has been useful in predictive ecology leading to the development of trait-based approaches (TBA). Until the late 1970s, however, limited effort (particularly in marine systems) was channeled towards patterns in functional species traits and how they may be affected by changes in environmental gradients. Here, I mapped the functional biogeography of the South African coastline based on a suite of species' reproduction and development traits. Because species composition is one of the key tools used by zoogeographers to map species distribution patterns, I expected lower variability in trait composition within main biogeographic regions than in intervening transition zones based on the habitat templet theory and following the biomass ratio and limiting similarity hypotheses. In brief, the habitat templet theory proposes that “the habitat provides a templet upon which evolution forges species characteristics”, while the biomass ratio hypothesis assumes that the most abundant species traits determine ecosystem functioning. The limiting similarity hypothesis also sometimes referred to as the niche complementarity hypothesis, however, predicts that species can coexist if their niches complement one another. In light of the habitat being an evolutionary templet, abiotic and biotic habitat patterns were measured as nearshore SST and chlorophyll-a gradients, respectively. I expected the SST gradient to act as the stronger key filter of trait diversification because temperature is often considered the most influential environmental factor affecting species survival with seasonality of SST affecting the timing of spawning and along with food availability, possibly influencing fecundity. Functional trait data were thus compiled for macroinvertebrate species collected from fifty-two rocky shore sites from three main bioregions (east, south, and west) and two transition zones (south-west and south-east). Biological trait analysis and functional diversity indices were used to evaluate how traits related to species development and reproduction respond to temperature and chlorophyll -a (used as a proxy for food availability) gradients along the coastline. GLMM and hierarchical cluster analyses showed distinct patterns/shifts in SST and chlorophyll-a gradients across bioregions, with two main breaks in SST separating the east and south-east overlap (SEO) bioregions from the south, south-west overlap (SWO) and west bioregions. In contrast, chlorophyll-a exhibited three major breaks with the east, SEO–south–SWO, and west clustering independently of each other. The RLQ analysis (a type of co-inertia analysis) which simultaneously ordinates 3-matrix datasets [i.e., (environment × site[R]), (species × site[L]) and (species × traits [Q])] showed that the higher SST gradient on the east and SEO promoted higher abundance and biomass of simultaneous hermaphrodites while higher chlorophyll-a gradients on the SWO and west coasts strongly promoted reproductive maturity at larger-sizes. The combined fourth-corner analyses showed that the modalities within the development trait domain responding to chlorophyll-a gradients primarily included filter feeders, sessile and swimming species and also species living on the infratidal zone. In addition, the reproduction trait domain showed higher sensitivity and association to differences in chlorophyll-a and SST gradients than development traits. Overall, SST and chlorophyll-a gradients influenced the distribution of the most dominant traits as indicated by shifts in community-weighted mean trait values across bioregions. This suggests the importance of habitat filtering on coastal species reproduction. A separate study evaluating the influence of large-scale biogeographic effects vs the micro-scale biogenic habitat structure offered by coralline seaweeds across 24 sites revealed some notable effects of both factors on the diversity and abundance of macroalgal epifauna. There was a notable biogeographic influence on epifauna, with the SEO recording the highest epifaunal species richness and abundance, followed by the south coast, then the SWO and lastly the west coast. In addition, the total biomass gradient of the corallines followed a similar trend. The epifauna however, showed no host-specificity, illustrating that epifauna may not be species–centric as commonly assumed, and the higher diversity of epifaunal diversity may well be simply because those corallines are the available habitat within the sampled part of the coastline. Lastly, macroinvertebrate trait distribution on the South African coastline confirms that the habitat, particularly the biotic filter (in this case chl-a) provides a templet upon which evolution forges species traits. However, since temperature is a proxy for nutrient availability (cold upwelling brings nutrients), then temperature drives chlorophyll-a. Subsequently this means the abiotic component indirectly drives trait distribution by influencing the biotic environment (chl-a). For epifauna species, also, the coralline diversity and composition can also be regarded as a biotic filter influencing the epifaunal abundances and composition across different bioregions. Moreover, since temperature is regarded as a conservative trait in seaweeds, temperature tolerance defines the biogeographical boundaries of seaweeds, therefore temperature may be indirectly affecting epifauna abundances through coralline species diversity and biomass. In summary, considering the deterministic processes governing ecosystem functioning and community assemblage, the mass ratio and limiting similarity hypotheses showed complementary effects. Different bioregions provided variable support for these two hypotheses, but overall, the mass ratio hypothesis (weighted by species biomass) received stronger support and may be more meaningful to the interpretation of ecosystem functioning and persistence within rocky shore systems. Lastly, although, the SWO showed some of the characteristics of a subtraction zone based on the relatively low abundance, diversity, and biomass measures. Nonetheless, there was evidence of high functional redundancy across all other four bioregions. This suggests that in the context of development and reproduction traits, the rocky shore ecosystem along the SA coastline may be functionally stable at this stage. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Gusha, Molline Natanah C
- Date: 2022-10-14
- Subjects: Biogeography , Marine algae , Benthic ecology , Invertebrates , Functional redundancy , Ocean temperature , Biology Classification
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365792 , vital:65790 , DOI https://doi.org/10.21504/10962/365792
- Description: Analyses of taxonomic diversity patterns within coastal systems has been critical in the development of the theory of biogeography. Increasing evidence, however, shows that the variety of functions that species perform in ecosystems (rather than their taxonomic identity) is a better predictor of the influence of the environment on the species. This information has been useful in predictive ecology leading to the development of trait-based approaches (TBA). Until the late 1970s, however, limited effort (particularly in marine systems) was channeled towards patterns in functional species traits and how they may be affected by changes in environmental gradients. Here, I mapped the functional biogeography of the South African coastline based on a suite of species' reproduction and development traits. Because species composition is one of the key tools used by zoogeographers to map species distribution patterns, I expected lower variability in trait composition within main biogeographic regions than in intervening transition zones based on the habitat templet theory and following the biomass ratio and limiting similarity hypotheses. In brief, the habitat templet theory proposes that “the habitat provides a templet upon which evolution forges species characteristics”, while the biomass ratio hypothesis assumes that the most abundant species traits determine ecosystem functioning. The limiting similarity hypothesis also sometimes referred to as the niche complementarity hypothesis, however, predicts that species can coexist if their niches complement one another. In light of the habitat being an evolutionary templet, abiotic and biotic habitat patterns were measured as nearshore SST and chlorophyll-a gradients, respectively. I expected the SST gradient to act as the stronger key filter of trait diversification because temperature is often considered the most influential environmental factor affecting species survival with seasonality of SST affecting the timing of spawning and along with food availability, possibly influencing fecundity. Functional trait data were thus compiled for macroinvertebrate species collected from fifty-two rocky shore sites from three main bioregions (east, south, and west) and two transition zones (south-west and south-east). Biological trait analysis and functional diversity indices were used to evaluate how traits related to species development and reproduction respond to temperature and chlorophyll -a (used as a proxy for food availability) gradients along the coastline. GLMM and hierarchical cluster analyses showed distinct patterns/shifts in SST and chlorophyll-a gradients across bioregions, with two main breaks in SST separating the east and south-east overlap (SEO) bioregions from the south, south-west overlap (SWO) and west bioregions. In contrast, chlorophyll-a exhibited three major breaks with the east, SEO–south–SWO, and west clustering independently of each other. The RLQ analysis (a type of co-inertia analysis) which simultaneously ordinates 3-matrix datasets [i.e., (environment × site[R]), (species × site[L]) and (species × traits [Q])] showed that the higher SST gradient on the east and SEO promoted higher abundance and biomass of simultaneous hermaphrodites while higher chlorophyll-a gradients on the SWO and west coasts strongly promoted reproductive maturity at larger-sizes. The combined fourth-corner analyses showed that the modalities within the development trait domain responding to chlorophyll-a gradients primarily included filter feeders, sessile and swimming species and also species living on the infratidal zone. In addition, the reproduction trait domain showed higher sensitivity and association to differences in chlorophyll-a and SST gradients than development traits. Overall, SST and chlorophyll-a gradients influenced the distribution of the most dominant traits as indicated by shifts in community-weighted mean trait values across bioregions. This suggests the importance of habitat filtering on coastal species reproduction. A separate study evaluating the influence of large-scale biogeographic effects vs the micro-scale biogenic habitat structure offered by coralline seaweeds across 24 sites revealed some notable effects of both factors on the diversity and abundance of macroalgal epifauna. There was a notable biogeographic influence on epifauna, with the SEO recording the highest epifaunal species richness and abundance, followed by the south coast, then the SWO and lastly the west coast. In addition, the total biomass gradient of the corallines followed a similar trend. The epifauna however, showed no host-specificity, illustrating that epifauna may not be species–centric as commonly assumed, and the higher diversity of epifaunal diversity may well be simply because those corallines are the available habitat within the sampled part of the coastline. Lastly, macroinvertebrate trait distribution on the South African coastline confirms that the habitat, particularly the biotic filter (in this case chl-a) provides a templet upon which evolution forges species traits. However, since temperature is a proxy for nutrient availability (cold upwelling brings nutrients), then temperature drives chlorophyll-a. Subsequently this means the abiotic component indirectly drives trait distribution by influencing the biotic environment (chl-a). For epifauna species, also, the coralline diversity and composition can also be regarded as a biotic filter influencing the epifaunal abundances and composition across different bioregions. Moreover, since temperature is regarded as a conservative trait in seaweeds, temperature tolerance defines the biogeographical boundaries of seaweeds, therefore temperature may be indirectly affecting epifauna abundances through coralline species diversity and biomass. In summary, considering the deterministic processes governing ecosystem functioning and community assemblage, the mass ratio and limiting similarity hypotheses showed complementary effects. Different bioregions provided variable support for these two hypotheses, but overall, the mass ratio hypothesis (weighted by species biomass) received stronger support and may be more meaningful to the interpretation of ecosystem functioning and persistence within rocky shore systems. Lastly, although, the SWO showed some of the characteristics of a subtraction zone based on the relatively low abundance, diversity, and biomass measures. Nonetheless, there was evidence of high functional redundancy across all other four bioregions. This suggests that in the context of development and reproduction traits, the rocky shore ecosystem along the SA coastline may be functionally stable at this stage. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-10-14
Scenarios for South Africa’s ocean economy towards 2060
- Authors: Hadi, Nomtha
- Date: 2022-04
- Subjects: Sustainable development--South Africa , Economic development--South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57676 , vital:58195
- Description: The ocean is becoming the new focal point in the discourse on growth and sustainable development, both at national and international levels. Scenario planning improves the quality of the strategic conversations that organisations need to have as a position in preparing for the future. In this research, scenarios for South Africa’s ocean economy towards 2060 were developed and explored by considering the six key ocean sectors as outlined in the Operations Phakisa Strategy, namely, Marine Transport and Manufacturing, Offshore Oil and Gas Exploration, Aquaculture, Small Harbours, Coastal and Marine Tourism, Marine Protection Services and Ocean Governance. The research process was guided by Inayatullah’s six pillars and linked methods towards scenario development. Existing studies do not take into consideration the various social, technological, economic, environmental, political, legislative and ethical factors influencing the growth of the ocean economy. With the ocean increasingly being considered a new economic frontier, sustainable development has become pertinent for supporting and facilitating continued economic growth areas without compromising on environmental, social, or economic factors. Sustainable development within the ocean economy is further supported by Goal 14 of the Sustainable Development Goals, which focuses on conservation and sustainable use of the ocean, sea and marine resources. A literature review was conducted to gain a better understanding of the ocean economy, and primary data was collected through a real-time Delphi platform and semi-structured interviews. The real-time Delphi collected information on the key megatrends that continue to shape the ocean economy and key drivers and wild cards that can affect the sustainability of the key ocean economy industries. In addition, semi-structured interviews collected information on the proposed scenarios and the capacity needed in growing and promoting a sustainable ocean economy for South Africa towards 2060. A scenario matrix was developed for South Africa’s ocean economy and four scenarios and their implications were analysed. The preferred scenario was a resilient ocean economy towards 2060. The study also took a step forward with a view to provide reference to stakeholders and governments in progressing towards a possible scenario and developed an integrated vision for a sustainable ocean economy for South Africa towards 2060. This proposed vision is to ABSTRACT v mitigate against future challenges, collaborate and proactively utilise the development opportunities offered by the ocean economy. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Hadi, Nomtha
- Date: 2022-04
- Subjects: Sustainable development--South Africa , Economic development--South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57676 , vital:58195
- Description: The ocean is becoming the new focal point in the discourse on growth and sustainable development, both at national and international levels. Scenario planning improves the quality of the strategic conversations that organisations need to have as a position in preparing for the future. In this research, scenarios for South Africa’s ocean economy towards 2060 were developed and explored by considering the six key ocean sectors as outlined in the Operations Phakisa Strategy, namely, Marine Transport and Manufacturing, Offshore Oil and Gas Exploration, Aquaculture, Small Harbours, Coastal and Marine Tourism, Marine Protection Services and Ocean Governance. The research process was guided by Inayatullah’s six pillars and linked methods towards scenario development. Existing studies do not take into consideration the various social, technological, economic, environmental, political, legislative and ethical factors influencing the growth of the ocean economy. With the ocean increasingly being considered a new economic frontier, sustainable development has become pertinent for supporting and facilitating continued economic growth areas without compromising on environmental, social, or economic factors. Sustainable development within the ocean economy is further supported by Goal 14 of the Sustainable Development Goals, which focuses on conservation and sustainable use of the ocean, sea and marine resources. A literature review was conducted to gain a better understanding of the ocean economy, and primary data was collected through a real-time Delphi platform and semi-structured interviews. The real-time Delphi collected information on the key megatrends that continue to shape the ocean economy and key drivers and wild cards that can affect the sustainability of the key ocean economy industries. In addition, semi-structured interviews collected information on the proposed scenarios and the capacity needed in growing and promoting a sustainable ocean economy for South Africa towards 2060. A scenario matrix was developed for South Africa’s ocean economy and four scenarios and their implications were analysed. The preferred scenario was a resilient ocean economy towards 2060. The study also took a step forward with a view to provide reference to stakeholders and governments in progressing towards a possible scenario and developed an integrated vision for a sustainable ocean economy for South Africa towards 2060. This proposed vision is to ABSTRACT v mitigate against future challenges, collaborate and proactively utilise the development opportunities offered by the ocean economy. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Improving hospital efficiency through preventative medical equipment maintenance intervention
- Authors: Hill, Michael Gary
- Date: 2022-04
- Subjects: Medical suppliers , Medical imaging equipment industry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57687 , vital:58200
- Description: This research study explores the management of medical equipment maintenance within South African Hospitals. The study aims to identify the risks and challenges Clinical Engineers experience at their facilities. This study was initiated because the author discovered multiple abandoned medical devices in a single ward that were not reported to the Clinical Engineering Department. This study compromises of secondary research in the form of a literature review that that explores Clinical engineering, the medical negligence claims and the importance of medical equipment maintenance and the management thereof. Primary data was collected from Clinical Engineers at various facilities, that were asked to participate in an online questionnaire. The primary research was based in a pragmatist paradigm with an inductive approach, using a mixed methods methodological choice. A survey strategy was used over a cross-sectional time horizon. The empirical results provided an understanding into how the Clinical Engineers are managing the maintenance of their medical equipment and the challenges that they face, looking at the inventory management systems, resource management, preventative maintenance, and fault reporting. Recommendations and conclusion were made relating to the findings of the primary research and the insight it provided. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Hill, Michael Gary
- Date: 2022-04
- Subjects: Medical suppliers , Medical imaging equipment industry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57687 , vital:58200
- Description: This research study explores the management of medical equipment maintenance within South African Hospitals. The study aims to identify the risks and challenges Clinical Engineers experience at their facilities. This study was initiated because the author discovered multiple abandoned medical devices in a single ward that were not reported to the Clinical Engineering Department. This study compromises of secondary research in the form of a literature review that that explores Clinical engineering, the medical negligence claims and the importance of medical equipment maintenance and the management thereof. Primary data was collected from Clinical Engineers at various facilities, that were asked to participate in an online questionnaire. The primary research was based in a pragmatist paradigm with an inductive approach, using a mixed methods methodological choice. A survey strategy was used over a cross-sectional time horizon. The empirical results provided an understanding into how the Clinical Engineers are managing the maintenance of their medical equipment and the challenges that they face, looking at the inventory management systems, resource management, preventative maintenance, and fault reporting. Recommendations and conclusion were made relating to the findings of the primary research and the insight it provided. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
An employer's ability to substitute a disciplinary hearing sanction
- Authors: Hlwatika, Siphile
- Date: 2022-04
- Subjects: Employees--Dismissal of--Law and legislation , Labor discipline--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55690 , vital:53407
- Description: It is common practice for employers to appoint external disciplinary hearing chairpersons to preside over a disciplinary hearing which has been convened for purposes of investigating allegations of misconduct against an employee. The external chairperson is ordinarily mandated to decide on guilt, and to the extent that there is a guilty finding, to recommend or impose the appropriate disciplinary sanction. Employers often tend to have expectations that the external chairperson will, after having found the employee guilty of the alleged misconduct, impose a sanction of dismissal. The expected outcome of dismissal, however, does not always occur. An external chairperson may impose a sanction short of dismissal after considering an disciplinary sanction may result in the employer instituting an internal review process to review the external chairperson employers may resort to unilaterally substituting the external disciplinary sanction with a sanction of dismissal. or the collective agreement regulating the disciplinary procedure in the workplace may or may not make provision for the substitution of the disciplinary sanction. In circumstances where there is no provision for the substitution of the disciplinary sanction, t questions regarding the applicability of the double jeopardy principle which means, in an employment context, that an employee should not be subjected to more than one disciplinary hearing on disciplinary charges arising from the same set of facts. It is, however, a well-established principle that employers who are classified as organs of state can review their own decisions. This includes decisions of chairpersons who are appointed preside over disciplinary hearings and decide on the appropriate disciplinary sanction. In the latter case, and in circumstances where the organ of state is dissatisfied with the disciplinary sanction, it may institute review proceedings in the Labour available to organs of state and not private-sector employers. This research seeks to determine whether it is permissible for an employer to substitute an external , and, if so, the circumstances under which an employer is allowed to do so and the procedure which should be followed in such an instance. , Thesis (LMM) -- Faculty of Law, Mercantile Law, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Hlwatika, Siphile
- Date: 2022-04
- Subjects: Employees--Dismissal of--Law and legislation , Labor discipline--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55690 , vital:53407
- Description: It is common practice for employers to appoint external disciplinary hearing chairpersons to preside over a disciplinary hearing which has been convened for purposes of investigating allegations of misconduct against an employee. The external chairperson is ordinarily mandated to decide on guilt, and to the extent that there is a guilty finding, to recommend or impose the appropriate disciplinary sanction. Employers often tend to have expectations that the external chairperson will, after having found the employee guilty of the alleged misconduct, impose a sanction of dismissal. The expected outcome of dismissal, however, does not always occur. An external chairperson may impose a sanction short of dismissal after considering an disciplinary sanction may result in the employer instituting an internal review process to review the external chairperson employers may resort to unilaterally substituting the external disciplinary sanction with a sanction of dismissal. or the collective agreement regulating the disciplinary procedure in the workplace may or may not make provision for the substitution of the disciplinary sanction. In circumstances where there is no provision for the substitution of the disciplinary sanction, t questions regarding the applicability of the double jeopardy principle which means, in an employment context, that an employee should not be subjected to more than one disciplinary hearing on disciplinary charges arising from the same set of facts. It is, however, a well-established principle that employers who are classified as organs of state can review their own decisions. This includes decisions of chairpersons who are appointed preside over disciplinary hearings and decide on the appropriate disciplinary sanction. In the latter case, and in circumstances where the organ of state is dissatisfied with the disciplinary sanction, it may institute review proceedings in the Labour available to organs of state and not private-sector employers. This research seeks to determine whether it is permissible for an employer to substitute an external , and, if so, the circumstances under which an employer is allowed to do so and the procedure which should be followed in such an instance. , Thesis (LMM) -- Faculty of Law, Mercantile Law, 2022
- Full Text:
- Date Issued: 2022-04
Water quality monitoring: a correlation Between the bacteriological quality of drinking water and Diarrhoeal prevalence within the Koukamma local municipality
- Authors: Jacobs, Nathan Elmar
- Date: 2022-04
- Subjects: Water quality monitoring stations -- Koukamma local municipality , Water quality management
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58882 , vital:60244
- Description: Background: Various studies have linked water quality and the prevalence of diarrhoeal cases within developing countries globally. The Emanti water quality monitoring system (eWQMS), representing the Kou-Kamma Local Municipality (Eastern Cape, South Africa), has often yielded non-complaint microbiological drinking water quality results retrospectively. This study investigated the relationship between the bacteriological quality of drinking water and diarrhoeal prevalence in children under five years of age within the Kou-Kamma Local Municipality from 2012 to 2016. Methods: A quantitative, descriptive, and ecological study design was employed retrospectively within the Kou-Kamma Local Municipality. Retrospective data collected from the Emanti Water Quality Monitoring System (eWQMS) represented the bacteriological quality of drinking water within the study area from 2012 to 2016. Concurrently, secondary data from the District Health Information Management System of the Eastern Cape Department of Health: Kouga Local service area was collected. The data represented cases of diarrhoea with dehydration in children under five years of age, reported at public health facilities within the study area retrospectively (from 2012 to 2016). Statistical analyses (Spearman's Rank Correlation) determined the relationship between the bacteriological quality of drinking water and the prevalence of diarrhoea in children under five years as per the retrospective period. Water samples were also collected for 2017 and 2018 to determine the presence of enteric pathogens in the municipal drinking water supply. Results: The study found that the Kou-Kamma Local Municipality had an overall noncompliance rate of 47% for the municipal drinking water supplied to the community from 2012 to 2016 (retrospective period). The difference in failure proportion (noncompliance) of water samples for the four climatic seasons where statistically significant (p=0.004). A significant difference was observed between autumn and winter (p=0.003) and autumn and spring (p=0.025). The failure proportion of water samples for autumn was significantly higher (mean = 0.603231, sd = 0.19528237) compared to winter (mean = 0.316675, sd = 0.19649776) and spring (mean = 0.374495, sd = 0.20626332). No significant difference was observed for the failure proportion of water samples between the various years of the retrospective period xvi (p=0.416). Children under the age of five accounted for n=460 cases of diarrhoea with dehydration at the public health facilities for the retrospective period. The Kareedouw area (n=196) and Joubertina area (n=134) recorded the highest diarrhoeal cases reported for the study period. These two areas both had hospitals that operated 24 hours a day; however, the differences in cases reported between the two areas was not statistically significant (p=0.179). Diarrhoeal case data reported between the various years within the study period were significantly different (p<0.001). The observed differences were between 2012 and 2014 (p=0.008) and 2012 and 2015 (p=0.001). The differences in the cases of diarrhoea with dehydration, in children under five years of age, were not statistically significant for the four climatic seasons (p=0.121). The relationship between the failure proportion of water samples and the prevalence of diarrhoea with dehydration in children under five years of age was statistically significant (p=0.001). The results revealed a moderate positive relationship (rs=0.434) between the bacteriological quality of drinking water and the prevalence of cases of diarrhoea with dehydration. Water samples were collected at various sampling points for July 2017 and November 2018 and analysed for enteric pathogens. Vibrio cholerae, Salmonella sp. and Shigella sp. were detected in such water samples collected. The relationship between the failure proportion of water samples and the presence of enteric pathogens was not statistically significant (rs=0.56723, p=0.240). Conclusion: The overall bacteriological quality of drinking water within the municipality was poor and likely posed a potential health risk to consumers. The study further revealed a steep rise of diarrhoeal with dehydration prevalence in children under five years of age during 2013, which decreased slowly during the years to follow. A moderate, positive relationship existed between the failure proportion of water samples and diarrhoea with dehydration prevalence in children under five years of age (rs=0.434, p=0.001 ). Therefore, municipalities should improve their bulk water infrastructure and drinking water disinfecting methods while realising the need for increased awareness of water-borne disease prevention. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Jacobs, Nathan Elmar
- Date: 2022-04
- Subjects: Water quality monitoring stations -- Koukamma local municipality , Water quality management
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58882 , vital:60244
- Description: Background: Various studies have linked water quality and the prevalence of diarrhoeal cases within developing countries globally. The Emanti water quality monitoring system (eWQMS), representing the Kou-Kamma Local Municipality (Eastern Cape, South Africa), has often yielded non-complaint microbiological drinking water quality results retrospectively. This study investigated the relationship between the bacteriological quality of drinking water and diarrhoeal prevalence in children under five years of age within the Kou-Kamma Local Municipality from 2012 to 2016. Methods: A quantitative, descriptive, and ecological study design was employed retrospectively within the Kou-Kamma Local Municipality. Retrospective data collected from the Emanti Water Quality Monitoring System (eWQMS) represented the bacteriological quality of drinking water within the study area from 2012 to 2016. Concurrently, secondary data from the District Health Information Management System of the Eastern Cape Department of Health: Kouga Local service area was collected. The data represented cases of diarrhoea with dehydration in children under five years of age, reported at public health facilities within the study area retrospectively (from 2012 to 2016). Statistical analyses (Spearman's Rank Correlation) determined the relationship between the bacteriological quality of drinking water and the prevalence of diarrhoea in children under five years as per the retrospective period. Water samples were also collected for 2017 and 2018 to determine the presence of enteric pathogens in the municipal drinking water supply. Results: The study found that the Kou-Kamma Local Municipality had an overall noncompliance rate of 47% for the municipal drinking water supplied to the community from 2012 to 2016 (retrospective period). The difference in failure proportion (noncompliance) of water samples for the four climatic seasons where statistically significant (p=0.004). A significant difference was observed between autumn and winter (p=0.003) and autumn and spring (p=0.025). The failure proportion of water samples for autumn was significantly higher (mean = 0.603231, sd = 0.19528237) compared to winter (mean = 0.316675, sd = 0.19649776) and spring (mean = 0.374495, sd = 0.20626332). No significant difference was observed for the failure proportion of water samples between the various years of the retrospective period xvi (p=0.416). Children under the age of five accounted for n=460 cases of diarrhoea with dehydration at the public health facilities for the retrospective period. The Kareedouw area (n=196) and Joubertina area (n=134) recorded the highest diarrhoeal cases reported for the study period. These two areas both had hospitals that operated 24 hours a day; however, the differences in cases reported between the two areas was not statistically significant (p=0.179). Diarrhoeal case data reported between the various years within the study period were significantly different (p<0.001). The observed differences were between 2012 and 2014 (p=0.008) and 2012 and 2015 (p=0.001). The differences in the cases of diarrhoea with dehydration, in children under five years of age, were not statistically significant for the four climatic seasons (p=0.121). The relationship between the failure proportion of water samples and the prevalence of diarrhoea with dehydration in children under five years of age was statistically significant (p=0.001). The results revealed a moderate positive relationship (rs=0.434) between the bacteriological quality of drinking water and the prevalence of cases of diarrhoea with dehydration. Water samples were collected at various sampling points for July 2017 and November 2018 and analysed for enteric pathogens. Vibrio cholerae, Salmonella sp. and Shigella sp. were detected in such water samples collected. The relationship between the failure proportion of water samples and the presence of enteric pathogens was not statistically significant (rs=0.56723, p=0.240). Conclusion: The overall bacteriological quality of drinking water within the municipality was poor and likely posed a potential health risk to consumers. The study further revealed a steep rise of diarrhoeal with dehydration prevalence in children under five years of age during 2013, which decreased slowly during the years to follow. A moderate, positive relationship existed between the failure proportion of water samples and diarrhoea with dehydration prevalence in children under five years of age (rs=0.434, p=0.001 ). Therefore, municipalities should improve their bulk water infrastructure and drinking water disinfecting methods while realising the need for increased awareness of water-borne disease prevention. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Characterization of Trypanosoma brucei Sti1 and its interactions with Trypanosoma brucei Hsp83 and human Hsp90
- Authors: Jamabo, Miebaka
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/422629 , vital:71963 , DOI 10.21504/10962/422629
- Description: Neglected tropical diseases continue to pose global concern due to their impact on health and socio-economic status of developing countries in sub-Saharan Africa. African trypanosomiasis is one of the neglected tropical diseases caused by the kinetoplastid flagellate parasite Trypanosoma brucei (T. brucei). The disease is fatal if untreated and the toolbox to combat the disease has been plagued with many difficulties such as drug resistance, toxic chemotherapeutics, and cumbersome drug delivery processes. In recent years, the disease has received attention from organizations such as the Drugs for Neglected Diseases initiative (DNDi) in partnership with WHO as well as academia and industry to provide alternatives to the existing drugs as part of a targeted approach to eliminate human African trypanosomiasis by 2030. The life cycle of the T. brucei parasite requires that it transitions between a cold-blooded vector (the tsetse fly) and a human host. To survive this extreme environmental change and maintain its infectious cycle, the parasite has evolved an arsenal of tools which include a strong immune evasion technique and a robust molecular chaperone system. Heat shock protein 90 (Hsp90) is one of the most abundant eukaryotic molecular chaperones that has been extensively studied in many organisms. It is indispensable for maintaining proteostasis in some organisms and its inhibition is currently being explored as a drug target for cancer and other parasitic diseases. In T. brucei, cytosolic Hsp90 is specifically referred to as Hsp83 due to variations in the sizes amongst different orthologues. Hsp90 is present in high levels in all stages of the T. brucei cell cycle both constitutively and on exposure to stress. To function in the cell, Hsp90 is dependent on co-chaperones, one of which can be found in most organisms, namely, the stress-inducible protein 1 (Sti1). The Hsp90-Sti1 interaction was shown to be crucial for growth in the intracellular kinetoplastid parasite, Leishmania donovani. However, this partnership has not been explored in the extracellular parasite T. brucei. To analyse the interaction of Hsp90 with Sti1 in T. brucei, this study combined in silico, in vitro and in vivo tools. In silico analyses of the Hsp90 complement in T. brucei revealed the presence of twelve putative Hsp90 genes, ten of which code for the cytosolic protein and are arranged in tandem in a head to tail fashion on the same chromosome. One gene each was found for the mitochondrial and ER paralogues of Hsp90, similar to all other species analysed. Eight putative co-chaperones specific to T. brucei were also discovered: six tetratricopeptide repeat domain (TPR) containing co-chaperones and two non-TPR containing co-chaperones. Structural and evolutionary analysis also confirmed that the domains were conserved across the species analysed. T. brucei Sti1 (TbSti1), T. brucei cytosolic Hsp90 (TbHsp83) and human cytosolic Hsp90 (hHsp90) were heterologously overproduced in E. coli and purified using nickel affinity chromatography. With specific antibodies, the expression and localization of the proteins were confirmed. TbSti1 showed strong affinity to the Hsp90s in the nanomolar range, with higher affinity for hHsp90 compared to TbHsp83. TbHsp83 and hHsp90 showed typical chaperone properties by suppressing the aggregation of thermolabile substrate MDH at equimolar concentrations and both chaperones had potent ATP hydrolysis activity. TbSti1, on the other hand, showed no MDH suppression activity and did not affect the ATP hydrolysis activity of TbHsp83 or hHsp90. Ex-vivo experiments using HeLa CRISPR Hop knockout (KO) human cell lines transfected with pcDNA3.1(+)HA-TbSti1 revealed TbSti1 also localized to the cytoplasm. The transfected cells showed a distinct fibroblast-like morphology which was different from the circular morphology seen in the Hop KO untransfected and wild type untransfected cells. Finally, co-immunoprecipitation studies revealed that TbSti1 co-immunoprecipitated with hHsp90. These results show the first characterization of the TbHsp83-TbSti1 partnership in T. brucei. The strong association between both proteins suggests a functional role for this partnership in T. brucei and could provide an updated context for understanding Trypanosome brucei biology. , Thesis (PhD) -- Faculty of Science, Biotechnology and Innovation Centre, 2023
- Full Text:
- Date Issued: 2023-03-31
- Authors: Jamabo, Miebaka
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/422629 , vital:71963 , DOI 10.21504/10962/422629
- Description: Neglected tropical diseases continue to pose global concern due to their impact on health and socio-economic status of developing countries in sub-Saharan Africa. African trypanosomiasis is one of the neglected tropical diseases caused by the kinetoplastid flagellate parasite Trypanosoma brucei (T. brucei). The disease is fatal if untreated and the toolbox to combat the disease has been plagued with many difficulties such as drug resistance, toxic chemotherapeutics, and cumbersome drug delivery processes. In recent years, the disease has received attention from organizations such as the Drugs for Neglected Diseases initiative (DNDi) in partnership with WHO as well as academia and industry to provide alternatives to the existing drugs as part of a targeted approach to eliminate human African trypanosomiasis by 2030. The life cycle of the T. brucei parasite requires that it transitions between a cold-blooded vector (the tsetse fly) and a human host. To survive this extreme environmental change and maintain its infectious cycle, the parasite has evolved an arsenal of tools which include a strong immune evasion technique and a robust molecular chaperone system. Heat shock protein 90 (Hsp90) is one of the most abundant eukaryotic molecular chaperones that has been extensively studied in many organisms. It is indispensable for maintaining proteostasis in some organisms and its inhibition is currently being explored as a drug target for cancer and other parasitic diseases. In T. brucei, cytosolic Hsp90 is specifically referred to as Hsp83 due to variations in the sizes amongst different orthologues. Hsp90 is present in high levels in all stages of the T. brucei cell cycle both constitutively and on exposure to stress. To function in the cell, Hsp90 is dependent on co-chaperones, one of which can be found in most organisms, namely, the stress-inducible protein 1 (Sti1). The Hsp90-Sti1 interaction was shown to be crucial for growth in the intracellular kinetoplastid parasite, Leishmania donovani. However, this partnership has not been explored in the extracellular parasite T. brucei. To analyse the interaction of Hsp90 with Sti1 in T. brucei, this study combined in silico, in vitro and in vivo tools. In silico analyses of the Hsp90 complement in T. brucei revealed the presence of twelve putative Hsp90 genes, ten of which code for the cytosolic protein and are arranged in tandem in a head to tail fashion on the same chromosome. One gene each was found for the mitochondrial and ER paralogues of Hsp90, similar to all other species analysed. Eight putative co-chaperones specific to T. brucei were also discovered: six tetratricopeptide repeat domain (TPR) containing co-chaperones and two non-TPR containing co-chaperones. Structural and evolutionary analysis also confirmed that the domains were conserved across the species analysed. T. brucei Sti1 (TbSti1), T. brucei cytosolic Hsp90 (TbHsp83) and human cytosolic Hsp90 (hHsp90) were heterologously overproduced in E. coli and purified using nickel affinity chromatography. With specific antibodies, the expression and localization of the proteins were confirmed. TbSti1 showed strong affinity to the Hsp90s in the nanomolar range, with higher affinity for hHsp90 compared to TbHsp83. TbHsp83 and hHsp90 showed typical chaperone properties by suppressing the aggregation of thermolabile substrate MDH at equimolar concentrations and both chaperones had potent ATP hydrolysis activity. TbSti1, on the other hand, showed no MDH suppression activity and did not affect the ATP hydrolysis activity of TbHsp83 or hHsp90. Ex-vivo experiments using HeLa CRISPR Hop knockout (KO) human cell lines transfected with pcDNA3.1(+)HA-TbSti1 revealed TbSti1 also localized to the cytoplasm. The transfected cells showed a distinct fibroblast-like morphology which was different from the circular morphology seen in the Hop KO untransfected and wild type untransfected cells. Finally, co-immunoprecipitation studies revealed that TbSti1 co-immunoprecipitated with hHsp90. These results show the first characterization of the TbHsp83-TbSti1 partnership in T. brucei. The strong association between both proteins suggests a functional role for this partnership in T. brucei and could provide an updated context for understanding Trypanosome brucei biology. , Thesis (PhD) -- Faculty of Science, Biotechnology and Innovation Centre, 2023
- Full Text:
- Date Issued: 2023-03-31
Development of a distributed optical fiber sensor for geological applications
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04