Hermēs Dolios: Performances of Hermes as trickster in the Homeric Hymn to Hermes
- Authors: Nel, Aiden Pieter
- Date: 2021-10-29
- Subjects: Hermes (Greek deity) , Hymn to Hermes , Tricksters in literature , Loki (Norse deity) , Hynes, William J , Doty, William G, 1939-J , Wakdjunkaga (Winnebago Trickster) , Ture (Zande Trickster)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190978 , vital:45046
- Description: This thesis explores the Greek god Hermes' representation in the Homeric Hymn to Hermes to establish the extent to which he partakes in Hynes' defined set of characteristics associated with mythological 'trickster' figures. Hermes is an unorthodox figure as although he embodies many aspects of the trickster, he willingly relinquishes some of these aspects within his hymn. I first outline and explore the trickster phenomenon and the complex methodological issue concerning global comparison. Hynes’ criteria are first applied to three other tricksters the Amerindian (Winnebago) trickster Wakdjunkaga, the central African (Azande) trickster Ture and the northern European (Norse) trickster Loki, which establishes a baseline that will help determine how Hermes conforms to this typology. All three figures’ cultural contexts are first addressed, as the cultural context is key in understanding a figure’s potential inclusion in the trickster category. I then explore Hermes’ performances within his hymn and other genres to formulate how his patron powers and actions relate to his designation as a trickster. I argue, in conclusion, that Hynes’ typology is a useful tool in determining any figure’s degree of ‘tricksterness’ and show that Hermes and the other three figures do embody Hynes’ characteristics. Each, however, embodies them differently and in a specific manner. I argue that the manner in which they relate to the criteria is dictated by their respective cultural contexts, and what their narrators intended to illustrate through the stories wherein tricksters reside. I further argue that narrative intent, genre and cultural context appear to be the main factors that mould each respective figure. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Nel, Aiden Pieter
- Date: 2021-10-29
- Subjects: Hermes (Greek deity) , Hymn to Hermes , Tricksters in literature , Loki (Norse deity) , Hynes, William J , Doty, William G, 1939-J , Wakdjunkaga (Winnebago Trickster) , Ture (Zande Trickster)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190978 , vital:45046
- Description: This thesis explores the Greek god Hermes' representation in the Homeric Hymn to Hermes to establish the extent to which he partakes in Hynes' defined set of characteristics associated with mythological 'trickster' figures. Hermes is an unorthodox figure as although he embodies many aspects of the trickster, he willingly relinquishes some of these aspects within his hymn. I first outline and explore the trickster phenomenon and the complex methodological issue concerning global comparison. Hynes’ criteria are first applied to three other tricksters the Amerindian (Winnebago) trickster Wakdjunkaga, the central African (Azande) trickster Ture and the northern European (Norse) trickster Loki, which establishes a baseline that will help determine how Hermes conforms to this typology. All three figures’ cultural contexts are first addressed, as the cultural context is key in understanding a figure’s potential inclusion in the trickster category. I then explore Hermes’ performances within his hymn and other genres to formulate how his patron powers and actions relate to his designation as a trickster. I argue, in conclusion, that Hynes’ typology is a useful tool in determining any figure’s degree of ‘tricksterness’ and show that Hermes and the other three figures do embody Hynes’ characteristics. Each, however, embodies them differently and in a specific manner. I argue that the manner in which they relate to the criteria is dictated by their respective cultural contexts, and what their narrators intended to illustrate through the stories wherein tricksters reside. I further argue that narrative intent, genre and cultural context appear to be the main factors that mould each respective figure. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
Hop-mediated alteration of cellular metabolism in KSHV infection
- Authors: Kirigin, Elisa
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192477 , vital:45229
- Description: Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Kirigin, Elisa
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192477 , vital:45229
- Description: Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
Human capital in the context of high levels of inequality in South Africa
- Authors: Friderichs, Tamaryn Jean
- Date: 2021-10-29
- Subjects: Human capital South Africa , Income distribution South Africa , Labor market South Africa , Latent variables , Confirmatory factor analysis , Education Economic aspects South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192672 , vital:45248 , 10.21504/10962/192672
- Description: Piketty’s (2014) book titled “Capital in the Twenty-First Century” sparked widespread interest in global inequality, the distinction between wealth and income inequality and the economic, social and political processes accounting for changes in economic inequality over time. Piketty’s (2014) study controversially stated that widening economic inequality is the normal state of affairs in capitalist societies. The return from capital/wealth (terms used interchangeably) will almost always outpace the returns from labour. In contrast with Piketty’s (2014) thesis that the returns on non-human capital drive growing income inequality, economists such as Leibbrandt et al. (2012), Van der Berg (2014) and Hundenborn et al. (2016) have found that the labour market and human capital (HC) are the primary sources of income inequality. The research problem for this study stems from these contrasting views. , Thesis (PhD) -- Faculty of Commerce, Economics and Economic History, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Friderichs, Tamaryn Jean
- Date: 2021-10-29
- Subjects: Human capital South Africa , Income distribution South Africa , Labor market South Africa , Latent variables , Confirmatory factor analysis , Education Economic aspects South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192672 , vital:45248 , 10.21504/10962/192672
- Description: Piketty’s (2014) book titled “Capital in the Twenty-First Century” sparked widespread interest in global inequality, the distinction between wealth and income inequality and the economic, social and political processes accounting for changes in economic inequality over time. Piketty’s (2014) study controversially stated that widening economic inequality is the normal state of affairs in capitalist societies. The return from capital/wealth (terms used interchangeably) will almost always outpace the returns from labour. In contrast with Piketty’s (2014) thesis that the returns on non-human capital drive growing income inequality, economists such as Leibbrandt et al. (2012), Van der Berg (2014) and Hundenborn et al. (2016) have found that the labour market and human capital (HC) are the primary sources of income inequality. The research problem for this study stems from these contrasting views. , Thesis (PhD) -- Faculty of Commerce, Economics and Economic History, 2021
- Full Text:
- Date Issued: 2021-10-29
Identification of potential inhibitors of the folate biosynthesis enzymes HPPK of Salmonella enterica and Escherichia coli and pteridine reductase of Trypanosoma brucei through molecular docking and enzyme assays
- Authors: Gerwel, Tiaan Marc
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192419 , vital:45224
- Description: Thesis (MSc (Pharm)) -- Faculty of Pharmacy, Pharmacy, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Gerwel, Tiaan Marc
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192419 , vital:45224
- Description: Thesis (MSc (Pharm)) -- Faculty of Pharmacy, Pharmacy, 2021
- Full Text:
- Date Issued: 2021-10-29
Improved concurrent Java processes
- Ntlahla, Mbalentle Apelele Wiseman
- Authors: Ntlahla, Mbalentle Apelele Wiseman
- Date: 2021-10-29
- Subjects: Java (Computer program language) , Computer multitasking , Sequential processing (Computer science) , Parallel programming (Computer science) , Simultaneous multithreading processors
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192129 , vital:45198
- Description: The rise in the number of cores in a processor has resulted in computer programmers needing to write concurrent programs to utilize the extra available processors. Concurrent programming can utilize the extra processors available in a multi-core architecture. However, writing concurrent programs introduces complexities that are not encountered in sequential programming (race conditions, deadlocks, starvation, liveness, etc., are some of the complexities that come with concurrent programming). These complexities require programming languages to provide functionality to help programmers with writing concurrent programs. The Java language is designed to support concurrent programming, mostly through threads. The support is provided through the Java programming language itself and Java class libraries. Although concurrent processes are important and have their own advantages over concurrent threads Java has limited support for concurrent processes. In this thesis we attempt to provide the same support that Java has for threads through the java.util.concurrent library to processes. This is attempted to be done through a Java library (za.co.jcp). The library will provide synchronisation methods of multiple processes, Java process shared variables, atomic variables, process-safe data structures, and a process executors framework similar to that of the executor framework provided by Java for threads. The two libraries' similarities, and performance is analyzed. The analysis between the two libraries is performed to compare the code portability, ease of use, and performance difference between the two libraries. The results from the project have shown that it is possible for Java to provide support for concurrency through processes and not only threads. In addition from the benchmarks performed the performance of the za.co.jcp library is not significantly slower than the current java.util.concurrent thread library. This means that Java concurrent applications will also now be able to use cooperating processes rather than be confined to using threads. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Ntlahla, Mbalentle Apelele Wiseman
- Date: 2021-10-29
- Subjects: Java (Computer program language) , Computer multitasking , Sequential processing (Computer science) , Parallel programming (Computer science) , Simultaneous multithreading processors
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192129 , vital:45198
- Description: The rise in the number of cores in a processor has resulted in computer programmers needing to write concurrent programs to utilize the extra available processors. Concurrent programming can utilize the extra processors available in a multi-core architecture. However, writing concurrent programs introduces complexities that are not encountered in sequential programming (race conditions, deadlocks, starvation, liveness, etc., are some of the complexities that come with concurrent programming). These complexities require programming languages to provide functionality to help programmers with writing concurrent programs. The Java language is designed to support concurrent programming, mostly through threads. The support is provided through the Java programming language itself and Java class libraries. Although concurrent processes are important and have their own advantages over concurrent threads Java has limited support for concurrent processes. In this thesis we attempt to provide the same support that Java has for threads through the java.util.concurrent library to processes. This is attempted to be done through a Java library (za.co.jcp). The library will provide synchronisation methods of multiple processes, Java process shared variables, atomic variables, process-safe data structures, and a process executors framework similar to that of the executor framework provided by Java for threads. The two libraries' similarities, and performance is analyzed. The analysis between the two libraries is performed to compare the code portability, ease of use, and performance difference between the two libraries. The results from the project have shown that it is possible for Java to provide support for concurrency through processes and not only threads. In addition from the benchmarks performed the performance of the za.co.jcp library is not significantly slower than the current java.util.concurrent thread library. This means that Java concurrent applications will also now be able to use cooperating processes rather than be confined to using threads. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
In silico identification of natural inhibitory compounds against the Mycobacterium tuberculosis Enzyme Pyrazinamidase using high-throughput virtual screening techniques
- Authors: Kenyon, Thomas
- Date: 2021-10-29
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Molecular dynamics , High throughput screening (Drug development) , Mutagenesis , South African Natural Compounds database (SANCDB)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192074 , vital:45193
- Description: Tuberculosis (TB) is most commonly a pulmonary infection caused by the bacterium Mycobacterium tuberculosis. With the exception of the COVID-19 pandemic, TB was the most common cause of death due to an infectious disease for a number of years up until 2020. In 2019, 10 million people fell ill with TB worldwide and 1.4 million people died (WHO, 2020a). Additionally, multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security threat. A global total of 206 030 people with multidrug- or rifampicin-resistant TB (MDR/RR-TB) were reported in 2019, a 10% increase from 186 883 in 2018. South Africa is ranked among the 48 high TB burden countries, with an estimated 360 000 people falling ill in 2019, resulting in 58 000 deaths, the majority of which being among people living with HIV. Unlike HIV, however, TB is a curable disease when managed correctly with long durations of antitubercular chemotherapy. Pyrazinamide (PZA) is an important first-line tuberculosis drug unique for its activity against latent TB. PZA is a prodrug, being converted into its active form, pyrazinoic acid (POA) by the Mtb gene pncA, coding for the pyrazinamidase enzyme (PZase). TB resistance to first-line drugs such as PZA is commonly associated with mutations in the pncA/PZase enzyme. This study aimed to identify potential novel inhibitors that bind to the active site of PZase. By making use of molecular docking studies and molecular dynamics (MD) simulations, high throughput virtual screening was performed on 623 compounds from the South African Natural Compounds database (SANCDB; https://sancdb.rubi.ru.ac.za). Ligands that selectively bound to the PZase active site were identified using docking studies, followed by MD simulations to assess ligand-PZase complex stability, Finally, hit compounds identified from the first round of MD simulations were screened again against PZase structures with high confidence point mutations known to infer PZA resistance in order to identify any novel compounds which had inhibitory potential against both WT and mutant forms of the PZase enzyme. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Kenyon, Thomas
- Date: 2021-10-29
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Molecular dynamics , High throughput screening (Drug development) , Mutagenesis , South African Natural Compounds database (SANCDB)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192074 , vital:45193
- Description: Tuberculosis (TB) is most commonly a pulmonary infection caused by the bacterium Mycobacterium tuberculosis. With the exception of the COVID-19 pandemic, TB was the most common cause of death due to an infectious disease for a number of years up until 2020. In 2019, 10 million people fell ill with TB worldwide and 1.4 million people died (WHO, 2020a). Additionally, multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security threat. A global total of 206 030 people with multidrug- or rifampicin-resistant TB (MDR/RR-TB) were reported in 2019, a 10% increase from 186 883 in 2018. South Africa is ranked among the 48 high TB burden countries, with an estimated 360 000 people falling ill in 2019, resulting in 58 000 deaths, the majority of which being among people living with HIV. Unlike HIV, however, TB is a curable disease when managed correctly with long durations of antitubercular chemotherapy. Pyrazinamide (PZA) is an important first-line tuberculosis drug unique for its activity against latent TB. PZA is a prodrug, being converted into its active form, pyrazinoic acid (POA) by the Mtb gene pncA, coding for the pyrazinamidase enzyme (PZase). TB resistance to first-line drugs such as PZA is commonly associated with mutations in the pncA/PZase enzyme. This study aimed to identify potential novel inhibitors that bind to the active site of PZase. By making use of molecular docking studies and molecular dynamics (MD) simulations, high throughput virtual screening was performed on 623 compounds from the South African Natural Compounds database (SANCDB; https://sancdb.rubi.ru.ac.za). Ligands that selectively bound to the PZase active site were identified using docking studies, followed by MD simulations to assess ligand-PZase complex stability, Finally, hit compounds identified from the first round of MD simulations were screened again against PZase structures with high confidence point mutations known to infer PZA resistance in order to identify any novel compounds which had inhibitory potential against both WT and mutant forms of the PZase enzyme. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
Inkcitha nzila nobomi obutsha (The release of the widow and life after mourning): Xhosa widows and citizenship
- Jimlongo, Gcotyelwa Nomxolisi
- Authors: Jimlongo, Gcotyelwa Nomxolisi
- Date: 2021-10-29
- Subjects: Widows South Africa Eastern Cape , Women, Black South Africa Eastern Cape , Xhosa (African people) South Africa Eastern Cape , Widows Social conditions , Widowhood Psychological aspects South Africa Eastern Cape , Widowhood Economic aspects South Africa Eastern Cape , Widowhood Social aspects South Africa Eastern Cape , Mourning customs South Africa Eastern Cape , Feminist economics South Africa Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192220 , vital:45206
- Description: This study examines the everyday conceptions and navigations of citizenship by Xhosa widows. It examines widows’ own understandings and experiences of citizenship once the official mourning period, known amongst amaXhosa as ukuzila, has ended. The study draws from 14 interviews with Xhosa widows from the Amalinda, Tsholomnqa, Mdantsane, Magcumeni, KwaNonkcampa, and Dimbaza areas in the Eastern Cape, South Africa. This thesis contextualises claims to widowhood in the context of democratic South Africa, and the various ways in which widowed women conceptualise their lives after ukuzila. While ukuzila itself is written about in the literature, the contentious claims to widowhood and the ways in which women come to make sense of their lives in the post-mourning period remains largely unexplored. Interviews were conducted with women who had undertaken customary and/or civil marriages, had divorced or separated from their partners, or had cohabited. They reveal that widowhood is tenuous and as such, remains contested and contestable. The study demonstrates that much of the claims to widowhood are made because of the undeniable labour that women perform during the partnerships, where they are the primary economic providers. The study shows that whether in the formal and informal sector, women have been central in building the economic livelihoods of their families. In the post-mourning period, the theme of ukuhlala (to stay) that is articulated by widows, shows that they choose to remain in their marital homes to protect what they have laboured for. The findings demonstrate that the key to ‘good’ widowhood is intricately linked to ‘good’ motherhood. For Xhosa widows, much of their decision-making, and livelihood strategies, rests on how they craft good livelihoods for their families. These include a negotiation of feminist economies with woman-centred networks, a reliance on spirituality, as well as negotiations for dignity and respect within the homestead through the protection and maintenance of what they have built over the years. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Jimlongo, Gcotyelwa Nomxolisi
- Date: 2021-10-29
- Subjects: Widows South Africa Eastern Cape , Women, Black South Africa Eastern Cape , Xhosa (African people) South Africa Eastern Cape , Widows Social conditions , Widowhood Psychological aspects South Africa Eastern Cape , Widowhood Economic aspects South Africa Eastern Cape , Widowhood Social aspects South Africa Eastern Cape , Mourning customs South Africa Eastern Cape , Feminist economics South Africa Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192220 , vital:45206
- Description: This study examines the everyday conceptions and navigations of citizenship by Xhosa widows. It examines widows’ own understandings and experiences of citizenship once the official mourning period, known amongst amaXhosa as ukuzila, has ended. The study draws from 14 interviews with Xhosa widows from the Amalinda, Tsholomnqa, Mdantsane, Magcumeni, KwaNonkcampa, and Dimbaza areas in the Eastern Cape, South Africa. This thesis contextualises claims to widowhood in the context of democratic South Africa, and the various ways in which widowed women conceptualise their lives after ukuzila. While ukuzila itself is written about in the literature, the contentious claims to widowhood and the ways in which women come to make sense of their lives in the post-mourning period remains largely unexplored. Interviews were conducted with women who had undertaken customary and/or civil marriages, had divorced or separated from their partners, or had cohabited. They reveal that widowhood is tenuous and as such, remains contested and contestable. The study demonstrates that much of the claims to widowhood are made because of the undeniable labour that women perform during the partnerships, where they are the primary economic providers. The study shows that whether in the formal and informal sector, women have been central in building the economic livelihoods of their families. In the post-mourning period, the theme of ukuhlala (to stay) that is articulated by widows, shows that they choose to remain in their marital homes to protect what they have laboured for. The findings demonstrate that the key to ‘good’ widowhood is intricately linked to ‘good’ motherhood. For Xhosa widows, much of their decision-making, and livelihood strategies, rests on how they craft good livelihoods for their families. These include a negotiation of feminist economies with woman-centred networks, a reliance on spirituality, as well as negotiations for dignity and respect within the homestead through the protection and maintenance of what they have built over the years. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
Integration of dual metallophthalocyanine catalysis and green energy for sustainable oxidative removal of endocrine disrupting compounds
- Authors: Kruid, Jan
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192820 , vital:45267
- Description: Thesis (PhD) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Kruid, Jan
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192820 , vital:45267
- Description: Thesis (PhD) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10-29
Integrative systematic structuring of the widespread psammophiid snakes (Psammophiidae): a multi-evidence species delineation approach
- Authors: Keates, Chad
- Date: 2021-10-29
- Subjects: Psammophis South Africa , Herpetology , Herpetology Africa , Molecular biology , Psammophis Classification , Psammophis Genetics , Psammophis Morphology , Psammophis Phylogeny , Morphology Mathematics , Psammophylax
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/295077 , vital:57288 , DOI 10.21504/10962/295079
- Description: Species form the foundations upon which we build our understanding of the natural world. Although a focus of much scientific attention, our understanding of species is stunted by the intrinsic ‘fuzziness’ of boundaries within nature. Due to the complexity of the evolutionary process, coupled with an ever-changing abiotic landscape, species are hard to delineate, even at the best of times. Whilst various species concepts and sophisticated delimitation methods have helped scientists tease apart species, many species complexes persist. This is because taxonomy is a discrete ordering system imposed upon the continuous and intercalated structure of life. To improve our understanding of a wide-ranging family of snakes, I investigated the taxonomy and evolutionary structuring within Psammophiidae using both molecular and morphological approaches, employing phylogenetic, phylogeographic, and morphometric analyses on the group. The systematic complexity of the family (as evidenced by past research) coupled with the group’s widespread distribution and ecological importance, made the taxon an ideal candidate for a broad-sweeping multi-level systematic analysis using multiple species delimitation methods. Additionally, in this thesis I attempted to build on the ground-breaking work of Christopher Kelly by addressing several knowledge gaps identified within the family, and in so doing, produce the most thorough evolutionary and taxonomic study of Psammophiidae possible. Given the taxonomic uncertainty associated with the family, Chapter Two used a representative sampling from every available species (near complete taxon sampling approach) in the family. The chapter used both standard and time-calibrated phylogenetic modelling and distance/threshold-based species delimitation, to elucidate the finer-level structuring within the family. Geometric morphometrics was used to determine whether there were diagnosable differences in head structure between the different genera. The final phylogenetic tree incorporated 320 samples, representing the most comprehensive phylogenetic reconstruction of the family to date. By using a near-complete taxon sampling approach, I was able to resolve previously unsupported relationships within the family whilst also identifying several novel instances of an under- and over-appreciation of species diversity within the family. Geometric morphometrics also identified clear distinctions between genera based on head shape (head width and ‘beakedness’). This chapter showcased the importance of complete taxon sampling and robust methodology for species delimitation and the deleterious effect of species concepts when implemented in isolation. In Chapter Three, I narrowed the scope of the study to focus on the genus level. Psammophylax (Fitzinger 1843) is an abundant, yet poorly studied genus of grass snakes, endemic to Africa. The generalist nature of the genus and wide-spanning distributions of the constituent species has given rise to several subspecies and a poor understanding of the taxonomic structuring within the genus. The overlapping distributions (sympatry) of many of Psammophylax species, coupled with the potential for cryptic speciation via mechanisms such as convergent evolution, made the group the ideal candidate for a broad-sweeping systematic study (as evidenced in Chapter Two). By applying the suite of analyses used in Chapter Two to the generic level, we aimed to determine the effectiveness of a multi-evidence species delineation approach when tackling systematic problems at lower taxonomic levels. A genetic phylogeny of six of the seven species was estimated using multiple phylogenetic and distance/ threshold-based species delimitation methods. To support the molecular analyses, we conducted morphological analyses on the body (traditional morphology) and head (geometric morphometrics) separately. Phylogenetic analyses recovered a similar topology to past studies, but with better resolution and node support. I found substantial genetic structuring within the genus, supported by significantly different head shapes between Ps. a. acutus and other Psammophylax species. Psammophylax a. acutus was recovered as sister to its congeners, and sequence divergence values and morphometrics supported its recognition as a new genus. Increased sampling in East Africa (Tanzania, Kenya, and Ethiopia) revealed that Psammophylax multisquamis is polyphyletic, necessitating the description of a new, morphologically cryptic, species from northern Tanzania. The distribution of Ps. multisquamis sensu stricto is likely restricted to Kenya and Ethiopia. Within this chapter, taxon-specific phylogenetic analyses yielded stronger intrageneric support as compared to Chapter Two, allowing for more defensible conclusions about taxonomical amendments. Geometric morphometrics proved similarly useful (as compared to Chapter Two) in teasing apart genera within the family but lacked the robustness to delineate species within Psammophylax with confidence, highlighting the apparent convergence of form within the genus. In Chapter Four, I investigated the evolutionary structuring within the Southern African endemic Psammophylax rhombeatus. The structural and environmental heterogeneity within the region has given rise to many morphological forms distributed throughout the country, with previous studies neglecting the associated molecular significance of these forms. Irrespective of their small sample sizes, both Chapter Two and Three identified substantial phylogenetic structuring within the species, making Ps. rhombeatus the ideal candidate for a multi-faceted systematic review, using a combination of phylogenetics, geometric morphometrics and, for the first time in this species, phylogeographic analyses. By investigating a single species, in detail, I was able to assess the effectiveness of the methodologies implemented in previous chapters on systematic sorting using the multi-evidence species delineation approach. Phylogenetic and haplotype analysis retrieved four well-supported clades: southeast South Africa (SESA), southwest South Africa (SWSA), north-eastern South Africa (NESA) and western South Africa (WSA). Although not variable enough to warrant taxonomic re-evaluation, the clades represented important genetic hotspots, with relatively high intraspecific genetic divergence values separating them, irrespective of the small geographic distances separating populations. This is likely a product of the taxon’s habitat-generalist lifestyle, enabling them to bypass vicariant barriers that might otherwise cause speciation in less versatile species. The clades are also geographically distinct, with little overlap, indicating previous vicariance, a finding that is supported by the split of Ps. rhombeatus from Ps. ocellatus in the mid-Pliocene, followed by the diversification of Ps. rhombeatus into four clades throughout the Pleistocene. The genetic structuring observed in Ps. rhombeatus may be a product of population expansion following ancient refugial isolation (potentially Last Glacial Maximum [LGM]). The molecular distinctiveness of the clades was not replicated in the morphological component of this chapter, with neither dorsal nor lateral geometric morphometric analyses of head shape showing any discernible distinctiveness based on geography. Whilst head shape has not been shown to be an effective delineator of evolutionary units at the species level (within this taxon), body colour, scalation, and snout-vent length has been linked to morphotypes within the species based on the work of Broadley (1966). These morphological groupings are loosely attributable to the molecular clades identified in the phylogenetic analyses, highlighting the complex interplay of genetic and morphological characteristics in the process of speciation, and their representation in systematic accounts. This thesis represents the most thorough evolutionary and systematic study of the family currently possible. In addition to identifying and describing both a new genus and species, this thesis also highlighted several instances of an over- and under-appreciation of species diversity within Psammophiidae. By applying a multi-evidence species delineation approach to this thesis, I show the intricacy of the evolutionary process (at various taxonomic levels) and showcase the ease to which species boundaries can be confounded when species concepts are implemented in isolation. These findings also highlighted the importance of sample size, sample range, species delimitation method on the outcome of taxonomic analyses, and their interpretation. Lastly, this thesis addressed the knowledge gaps left by Christopher Kelly’s PhD work and investigated the findings of recent papers that attempted to do the same. Whilst this study answers the questions of old, the taxon-intensive focus revealed several new knowledge gaps within the family, highlighting how much we know about snake systematics, and furthermore, how much we still need to learn about evolutionary structuring. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Keates, Chad
- Date: 2021-10-29
- Subjects: Psammophis South Africa , Herpetology , Herpetology Africa , Molecular biology , Psammophis Classification , Psammophis Genetics , Psammophis Morphology , Psammophis Phylogeny , Morphology Mathematics , Psammophylax
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/295077 , vital:57288 , DOI 10.21504/10962/295079
- Description: Species form the foundations upon which we build our understanding of the natural world. Although a focus of much scientific attention, our understanding of species is stunted by the intrinsic ‘fuzziness’ of boundaries within nature. Due to the complexity of the evolutionary process, coupled with an ever-changing abiotic landscape, species are hard to delineate, even at the best of times. Whilst various species concepts and sophisticated delimitation methods have helped scientists tease apart species, many species complexes persist. This is because taxonomy is a discrete ordering system imposed upon the continuous and intercalated structure of life. To improve our understanding of a wide-ranging family of snakes, I investigated the taxonomy and evolutionary structuring within Psammophiidae using both molecular and morphological approaches, employing phylogenetic, phylogeographic, and morphometric analyses on the group. The systematic complexity of the family (as evidenced by past research) coupled with the group’s widespread distribution and ecological importance, made the taxon an ideal candidate for a broad-sweeping multi-level systematic analysis using multiple species delimitation methods. Additionally, in this thesis I attempted to build on the ground-breaking work of Christopher Kelly by addressing several knowledge gaps identified within the family, and in so doing, produce the most thorough evolutionary and taxonomic study of Psammophiidae possible. Given the taxonomic uncertainty associated with the family, Chapter Two used a representative sampling from every available species (near complete taxon sampling approach) in the family. The chapter used both standard and time-calibrated phylogenetic modelling and distance/threshold-based species delimitation, to elucidate the finer-level structuring within the family. Geometric morphometrics was used to determine whether there were diagnosable differences in head structure between the different genera. The final phylogenetic tree incorporated 320 samples, representing the most comprehensive phylogenetic reconstruction of the family to date. By using a near-complete taxon sampling approach, I was able to resolve previously unsupported relationships within the family whilst also identifying several novel instances of an under- and over-appreciation of species diversity within the family. Geometric morphometrics also identified clear distinctions between genera based on head shape (head width and ‘beakedness’). This chapter showcased the importance of complete taxon sampling and robust methodology for species delimitation and the deleterious effect of species concepts when implemented in isolation. In Chapter Three, I narrowed the scope of the study to focus on the genus level. Psammophylax (Fitzinger 1843) is an abundant, yet poorly studied genus of grass snakes, endemic to Africa. The generalist nature of the genus and wide-spanning distributions of the constituent species has given rise to several subspecies and a poor understanding of the taxonomic structuring within the genus. The overlapping distributions (sympatry) of many of Psammophylax species, coupled with the potential for cryptic speciation via mechanisms such as convergent evolution, made the group the ideal candidate for a broad-sweeping systematic study (as evidenced in Chapter Two). By applying the suite of analyses used in Chapter Two to the generic level, we aimed to determine the effectiveness of a multi-evidence species delineation approach when tackling systematic problems at lower taxonomic levels. A genetic phylogeny of six of the seven species was estimated using multiple phylogenetic and distance/ threshold-based species delimitation methods. To support the molecular analyses, we conducted morphological analyses on the body (traditional morphology) and head (geometric morphometrics) separately. Phylogenetic analyses recovered a similar topology to past studies, but with better resolution and node support. I found substantial genetic structuring within the genus, supported by significantly different head shapes between Ps. a. acutus and other Psammophylax species. Psammophylax a. acutus was recovered as sister to its congeners, and sequence divergence values and morphometrics supported its recognition as a new genus. Increased sampling in East Africa (Tanzania, Kenya, and Ethiopia) revealed that Psammophylax multisquamis is polyphyletic, necessitating the description of a new, morphologically cryptic, species from northern Tanzania. The distribution of Ps. multisquamis sensu stricto is likely restricted to Kenya and Ethiopia. Within this chapter, taxon-specific phylogenetic analyses yielded stronger intrageneric support as compared to Chapter Two, allowing for more defensible conclusions about taxonomical amendments. Geometric morphometrics proved similarly useful (as compared to Chapter Two) in teasing apart genera within the family but lacked the robustness to delineate species within Psammophylax with confidence, highlighting the apparent convergence of form within the genus. In Chapter Four, I investigated the evolutionary structuring within the Southern African endemic Psammophylax rhombeatus. The structural and environmental heterogeneity within the region has given rise to many morphological forms distributed throughout the country, with previous studies neglecting the associated molecular significance of these forms. Irrespective of their small sample sizes, both Chapter Two and Three identified substantial phylogenetic structuring within the species, making Ps. rhombeatus the ideal candidate for a multi-faceted systematic review, using a combination of phylogenetics, geometric morphometrics and, for the first time in this species, phylogeographic analyses. By investigating a single species, in detail, I was able to assess the effectiveness of the methodologies implemented in previous chapters on systematic sorting using the multi-evidence species delineation approach. Phylogenetic and haplotype analysis retrieved four well-supported clades: southeast South Africa (SESA), southwest South Africa (SWSA), north-eastern South Africa (NESA) and western South Africa (WSA). Although not variable enough to warrant taxonomic re-evaluation, the clades represented important genetic hotspots, with relatively high intraspecific genetic divergence values separating them, irrespective of the small geographic distances separating populations. This is likely a product of the taxon’s habitat-generalist lifestyle, enabling them to bypass vicariant barriers that might otherwise cause speciation in less versatile species. The clades are also geographically distinct, with little overlap, indicating previous vicariance, a finding that is supported by the split of Ps. rhombeatus from Ps. ocellatus in the mid-Pliocene, followed by the diversification of Ps. rhombeatus into four clades throughout the Pleistocene. The genetic structuring observed in Ps. rhombeatus may be a product of population expansion following ancient refugial isolation (potentially Last Glacial Maximum [LGM]). The molecular distinctiveness of the clades was not replicated in the morphological component of this chapter, with neither dorsal nor lateral geometric morphometric analyses of head shape showing any discernible distinctiveness based on geography. Whilst head shape has not been shown to be an effective delineator of evolutionary units at the species level (within this taxon), body colour, scalation, and snout-vent length has been linked to morphotypes within the species based on the work of Broadley (1966). These morphological groupings are loosely attributable to the molecular clades identified in the phylogenetic analyses, highlighting the complex interplay of genetic and morphological characteristics in the process of speciation, and their representation in systematic accounts. This thesis represents the most thorough evolutionary and systematic study of the family currently possible. In addition to identifying and describing both a new genus and species, this thesis also highlighted several instances of an over- and under-appreciation of species diversity within Psammophiidae. By applying a multi-evidence species delineation approach to this thesis, I show the intricacy of the evolutionary process (at various taxonomic levels) and showcase the ease to which species boundaries can be confounded when species concepts are implemented in isolation. These findings also highlighted the importance of sample size, sample range, species delimitation method on the outcome of taxonomic analyses, and their interpretation. Lastly, this thesis addressed the knowledge gaps left by Christopher Kelly’s PhD work and investigated the findings of recent papers that attempted to do the same. Whilst this study answers the questions of old, the taxon-intensive focus revealed several new knowledge gaps within the family, highlighting how much we know about snake systematics, and furthermore, how much we still need to learn about evolutionary structuring. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Investigation of microbial fuel cell technologies for flexible, small-scale domestic and educational use
- Authors: Mpofu, Trisha Lerato
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192539 , vital:45235
- Description: Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Mpofu, Trisha Lerato
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192539 , vital:45235
- Description: Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10-29
Jungle Drive and Other Stories
- Authors: Koenig, Nathalie
- Date: 2021-10-29
- Subjects: Creative writing (Higher education) South Africa , South African fiction (English) 21st century , South African poetry (English) 21st century , Short stories, South African (English) 21st century
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192225 , vital:45207
- Description: My thesis comprises prose in a variety of forms with porous borders, including the short story, flash fiction and prose poetry. I am attracted to a processual approach to writing as I like the potential for experimentation with spontaneity and textual improvisation within and across forms that this allows. I am influenced by Joanna Ruocco’s novellas, The Mothering Coven and Dan, whose worlds are built with generously scattered references, interesting words and strange features, delivered in a dead-pan tone that joyfully scrambles my logic. At the same time, I am inspired by the precision and beauty of Tina May Hall’s prose, and how she plays in the space between the natural and magical worlds. In addition, I draw on the musicality and rhythm of Noy Holland and JA Tyler’s prose, adding a corporeal layer to the words, sounds and movement of the text. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Koenig, Nathalie
- Date: 2021-10-29
- Subjects: Creative writing (Higher education) South Africa , South African fiction (English) 21st century , South African poetry (English) 21st century , Short stories, South African (English) 21st century
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192225 , vital:45207
- Description: My thesis comprises prose in a variety of forms with porous borders, including the short story, flash fiction and prose poetry. I am attracted to a processual approach to writing as I like the potential for experimentation with spontaneity and textual improvisation within and across forms that this allows. I am influenced by Joanna Ruocco’s novellas, The Mothering Coven and Dan, whose worlds are built with generously scattered references, interesting words and strange features, delivered in a dead-pan tone that joyfully scrambles my logic. At the same time, I am inspired by the precision and beauty of Tina May Hall’s prose, and how she plays in the space between the natural and magical worlds. In addition, I draw on the musicality and rhythm of Noy Holland and JA Tyler’s prose, adding a corporeal layer to the words, sounds and movement of the text. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
Language and the Thing in Itself in the fiction of John Banville
- Authors: Payne, Jessica Raechel
- Date: 2021-10-29
- Subjects: Banville, John Criticism and interpretation , English literature 20th century History and criticism , Language and languages in literature , Narrative inquiry (Research method) , Hermeneutics , Excess (Philosophy) , Literary criticism
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190019 , vital:44956
- Description: This thesis consists of an exploration of the interaction between language and the thing in itself in the fiction of John Banville. The thing in itself is that which exceeds the text and to which it cannot refer, even as it is compelled to do so. In exploring this tension, the thesis focuses on how Banville’s writing, in foregrounding the inadequacy of the literary text, makes the reader aware of the existence of what exceeds it. Each of the chapters in the study examines the various strategies through which Banville gestures beyond the text in spite of the limitations placed upon him by form and genre. The first chapter studies the tendency in this writer’s texts to view death as an apotheosis of the soul in which the individual finally has access to the thing in itself, which they had previously encountered as infants before entering language. The second chapter examines how elements of Romantic thought, such as nostalgia, the seniority of the child over the adult and a particular impression of the natural world, contribute to Banville’s attempt to gesture towards the thing in itself. In the third chapter, the role of language in distorting one’s understanding of the other is examined. The final chapter of the thesis examines the narrative strategies (including mise en abyme, ekphrasis, metaphor and catachresis) Banville uses in order to present the reader with excess. Ultimately, this study suggests that Banville uses various narrative strategies to make his reader aware of that which exists outside of the text. By gesturing beyond the novel to the sublime, and by self-reflexively exposing the inner workings of the writing process to the reader, Banville’s texts confront the reader with an intimation of ineluctable excess. , Thesis (MA) -- Faculty of Humanities, Literary Studies in English, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Payne, Jessica Raechel
- Date: 2021-10-29
- Subjects: Banville, John Criticism and interpretation , English literature 20th century History and criticism , Language and languages in literature , Narrative inquiry (Research method) , Hermeneutics , Excess (Philosophy) , Literary criticism
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190019 , vital:44956
- Description: This thesis consists of an exploration of the interaction between language and the thing in itself in the fiction of John Banville. The thing in itself is that which exceeds the text and to which it cannot refer, even as it is compelled to do so. In exploring this tension, the thesis focuses on how Banville’s writing, in foregrounding the inadequacy of the literary text, makes the reader aware of the existence of what exceeds it. Each of the chapters in the study examines the various strategies through which Banville gestures beyond the text in spite of the limitations placed upon him by form and genre. The first chapter studies the tendency in this writer’s texts to view death as an apotheosis of the soul in which the individual finally has access to the thing in itself, which they had previously encountered as infants before entering language. The second chapter examines how elements of Romantic thought, such as nostalgia, the seniority of the child over the adult and a particular impression of the natural world, contribute to Banville’s attempt to gesture towards the thing in itself. In the third chapter, the role of language in distorting one’s understanding of the other is examined. The final chapter of the thesis examines the narrative strategies (including mise en abyme, ekphrasis, metaphor and catachresis) Banville uses in order to present the reader with excess. Ultimately, this study suggests that Banville uses various narrative strategies to make his reader aware of that which exists outside of the text. By gesturing beyond the novel to the sublime, and by self-reflexively exposing the inner workings of the writing process to the reader, Banville’s texts confront the reader with an intimation of ineluctable excess. , Thesis (MA) -- Faculty of Humanities, Literary Studies in English, 2021
- Full Text:
- Date Issued: 2021-10-29
Legal ethics and the lawyer-client relationship in South Africa: A proposal for reform using local values
- Authors: Kruuse, Helen Julia
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192765 , vital:45262
- Description: Thesis (PhD) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Kruuse, Helen Julia
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192765 , vital:45262
- Description: Thesis (PhD) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-10-29
L’analyse du Panafricanisme dans la littérature africaine d’expression française: étude de Les Soleils des Indépendances d’Ahmadou Kourouma
- Batubenga David-Roger, Ndaye
- Authors: Batubenga David-Roger, Ndaye
- Date: 2021-10-29
- Subjects: African literature (French) History and criticism , Kourouma, Ahmadou. Soleils des indépendances , Pan-Africanism in literature , Postcolonialism in literature , Africans in literature , Identity (Philosophical concept) in literature , Ethnicity in literature
- Language: French
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:45204
- Description: Analysis of pan-Africanism in French African literature: case study of The Suns of independences by Ahmadou Kourouma. (L’analyse du Panafricanisme dans la littérature africaine d’expression française : étude des Soleils des Indépendances d’Ahmadou Kourouma) This study seeks to analyse the concept of pan-Africanism in French African Literature as depicted in The Suns of independences by Ahmadou Kourouma. The theme as well as the plot of the novel are both part of the post-colonial era, when African states acceded to the so-called national sovereignty. Theoretically, this was the end of colonization. Indeed, the advent of independence in Africa was, among other things, the fulfilment of one of the objectives of the pan-Africanism movement. Those objectives, according to Estanilas Ngodi (2003:6), were to promote the well-being as well as the unity of African people and those of African descendants around the world; to ensure equal civic rights for African people; to ensure the total abolition of all forms of racial discrimination; and to demand a self-determination and genuine independence of and for African’s people and states. To understand this challenging concept of pan-Africanism, we will draw inspiration from the studies of Edward Wilmot Blyden (1832-1912) who defined it as emerging a distinctive African personality: It is accepted in this study that the manner in and the extent to which the concept of pan-Africanism will be analysed should not be confused with other concepts such as Negroism or Negritude. The concern of asserting African history and identity by African people is justified by the fact that for centuries the philosophical and anthropological Eurocentric trend that Africans and their cultures and knowledge had no value. For this purpose, Trevor Roper (1963:871) asserted: “Perhaps in the future, there will be some African history, but at present, there is none; only the history of Europeans in Africa. The rest is darkness…and darkness is not a subject of history…” This denial of African history and civilization was, according to Europeans, the reason for the slave trade and colonization, and the development of pan-Africanism was the reaction or resistance against these views. That is the reason why, in the novel (The Suns of 4 independences), Kourouma depicts the concept of pan-Africanism and reveals the need for African people to assert themselves in humanity as being equal to all other races. Indeed, the advent of independence in Africa was an opportunity for Africans to regain their pre-colonial roots. Because it raised hopes and expectations to see Africa being led by its own sons. Unfortunately, independences have become a missed rendezvous or a disappointment for Africans. This argument is confirmed by the metaphor of Fama, a traditional king in the post-independence Africa: find himself “dried and undressed by colonization and Independences” (p.116). Broadly speaking, Kourouma interrogates the evolution of African societies in the light of pan-Africanism and denounces political, economic, and social issues that are affecting Africa in the post-colonial era. These issues include dictatorship, mismanagement, corruption, poverty, and the challenge of regaining African personality from colonial influence. What differentiates my study from the previous research is that I seek to investigate to which extent Kourouma portrays the failure of African society in the light of pan-Africanism before and after the colonialist era, and the impact of this failure upon the establishment of the pan-Africanist vision in Africa. Little attention has been given to the analysis of this novel (The Suns of independences) in this perspective. Kourouma is an Ivorian writer. In 1970, he published his first novel (The Suns of Independences) which is considered as a masterpiece in French African Literature and which many critics have classified it as one of the founding works in African Literature. In this study, in accordance with the novel above-mentioned I have considered three different aspects of pan-Africanism. Firstly, I described pan-Africanism as the search for the dignity of black people. Secondly, I examined it as the desire of regaining or rebuilding the African unity (African states without colonial borders). Thirdly, I analysed it as the return of African people to their history, their origin, and their cultural identity, in short, the return of Africa to its original state before the slave trade and colonization. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Batubenga David-Roger, Ndaye
- Date: 2021-10-29
- Subjects: African literature (French) History and criticism , Kourouma, Ahmadou. Soleils des indépendances , Pan-Africanism in literature , Postcolonialism in literature , Africans in literature , Identity (Philosophical concept) in literature , Ethnicity in literature
- Language: French
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:45204
- Description: Analysis of pan-Africanism in French African literature: case study of The Suns of independences by Ahmadou Kourouma. (L’analyse du Panafricanisme dans la littérature africaine d’expression française : étude des Soleils des Indépendances d’Ahmadou Kourouma) This study seeks to analyse the concept of pan-Africanism in French African Literature as depicted in The Suns of independences by Ahmadou Kourouma. The theme as well as the plot of the novel are both part of the post-colonial era, when African states acceded to the so-called national sovereignty. Theoretically, this was the end of colonization. Indeed, the advent of independence in Africa was, among other things, the fulfilment of one of the objectives of the pan-Africanism movement. Those objectives, according to Estanilas Ngodi (2003:6), were to promote the well-being as well as the unity of African people and those of African descendants around the world; to ensure equal civic rights for African people; to ensure the total abolition of all forms of racial discrimination; and to demand a self-determination and genuine independence of and for African’s people and states. To understand this challenging concept of pan-Africanism, we will draw inspiration from the studies of Edward Wilmot Blyden (1832-1912) who defined it as emerging a distinctive African personality: It is accepted in this study that the manner in and the extent to which the concept of pan-Africanism will be analysed should not be confused with other concepts such as Negroism or Negritude. The concern of asserting African history and identity by African people is justified by the fact that for centuries the philosophical and anthropological Eurocentric trend that Africans and their cultures and knowledge had no value. For this purpose, Trevor Roper (1963:871) asserted: “Perhaps in the future, there will be some African history, but at present, there is none; only the history of Europeans in Africa. The rest is darkness…and darkness is not a subject of history…” This denial of African history and civilization was, according to Europeans, the reason for the slave trade and colonization, and the development of pan-Africanism was the reaction or resistance against these views. That is the reason why, in the novel (The Suns of 4 independences), Kourouma depicts the concept of pan-Africanism and reveals the need for African people to assert themselves in humanity as being equal to all other races. Indeed, the advent of independence in Africa was an opportunity for Africans to regain their pre-colonial roots. Because it raised hopes and expectations to see Africa being led by its own sons. Unfortunately, independences have become a missed rendezvous or a disappointment for Africans. This argument is confirmed by the metaphor of Fama, a traditional king in the post-independence Africa: find himself “dried and undressed by colonization and Independences” (p.116). Broadly speaking, Kourouma interrogates the evolution of African societies in the light of pan-Africanism and denounces political, economic, and social issues that are affecting Africa in the post-colonial era. These issues include dictatorship, mismanagement, corruption, poverty, and the challenge of regaining African personality from colonial influence. What differentiates my study from the previous research is that I seek to investigate to which extent Kourouma portrays the failure of African society in the light of pan-Africanism before and after the colonialist era, and the impact of this failure upon the establishment of the pan-Africanist vision in Africa. Little attention has been given to the analysis of this novel (The Suns of independences) in this perspective. Kourouma is an Ivorian writer. In 1970, he published his first novel (The Suns of Independences) which is considered as a masterpiece in French African Literature and which many critics have classified it as one of the founding works in African Literature. In this study, in accordance with the novel above-mentioned I have considered three different aspects of pan-Africanism. Firstly, I described pan-Africanism as the search for the dignity of black people. Secondly, I examined it as the desire of regaining or rebuilding the African unity (African states without colonial borders). Thirdly, I analysed it as the return of African people to their history, their origin, and their cultural identity, in short, the return of Africa to its original state before the slave trade and colonization. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
Media consumption and identity formation: the consumption of Latin American telenovelas in two neighbourhoods of Maputo in Mozambique
- Authors: Ofumane, Alvo Naftal
- Date: 2021-10-29
- Subjects: Television soap operas Mozambique Maputo , Identity (Psychology) and mass media Mozambique Maputo , Television soap operas History and criticism , Visual reception theory Mozambique Maputo , Mozambique Politics and government , Mozambique Social conditions , Mozambique Social life and customs
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192287 , vital:45212
- Description: This study explores how the residents of two neighbourhoods in Maputo, KaMaxakeni and KaMpfumo interact with and make meanings of (Latin American) telenovelas, as part of their identity formation process. It is guided by questions on how the residents of these two neighbourhoods interact with telenovelas in their daily lives; how this shapes their own values and understanding of themselves and the world in which they live; what aspects of telenovelas they value, and what meanings they make from them; and, finally, what determines their choices of media consumption. The study adopted reception theory, rooted in qualitative methodology. This approach explores the ‘insider’s’ perspective of the research subjects, taking the actors’ perspective as the empirical point of departure. Using a purposive theoretical sampling procedure, targeting those families who are avid viewers of telenovelas, the data were generated through participant observation, focus groups discussions, and individual interviews. To understand and interpret the interface between the telenovela (medium) and its viewers (audience) in Maputo, the study used qualitative thematic content analysis of the telenovelas viewing process by the residents of KaMpfumo and KaMaxakeni. The data show that the residents of KaMpfumo and KaMaxakeni in Maputo interact and make sense of the telenovelas in various ways. Telenovelas are used as an educational tool; they are used to reinforce daily life world practices; they s shape people’s personal character; they become another family presence; they are used to build or strengthen physical and virtual viewing networks, and, “Pure” telenovela viewing is a relatively rare occurrence. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Ofumane, Alvo Naftal
- Date: 2021-10-29
- Subjects: Television soap operas Mozambique Maputo , Identity (Psychology) and mass media Mozambique Maputo , Television soap operas History and criticism , Visual reception theory Mozambique Maputo , Mozambique Politics and government , Mozambique Social conditions , Mozambique Social life and customs
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192287 , vital:45212
- Description: This study explores how the residents of two neighbourhoods in Maputo, KaMaxakeni and KaMpfumo interact with and make meanings of (Latin American) telenovelas, as part of their identity formation process. It is guided by questions on how the residents of these two neighbourhoods interact with telenovelas in their daily lives; how this shapes their own values and understanding of themselves and the world in which they live; what aspects of telenovelas they value, and what meanings they make from them; and, finally, what determines their choices of media consumption. The study adopted reception theory, rooted in qualitative methodology. This approach explores the ‘insider’s’ perspective of the research subjects, taking the actors’ perspective as the empirical point of departure. Using a purposive theoretical sampling procedure, targeting those families who are avid viewers of telenovelas, the data were generated through participant observation, focus groups discussions, and individual interviews. To understand and interpret the interface between the telenovela (medium) and its viewers (audience) in Maputo, the study used qualitative thematic content analysis of the telenovelas viewing process by the residents of KaMpfumo and KaMaxakeni. The data show that the residents of KaMpfumo and KaMaxakeni in Maputo interact and make sense of the telenovelas in various ways. Telenovelas are used as an educational tool; they are used to reinforce daily life world practices; they s shape people’s personal character; they become another family presence; they are used to build or strengthen physical and virtual viewing networks, and, “Pure” telenovela viewing is a relatively rare occurrence. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
Mediating and examining expansive learning in the context of multidimensional complexities affecting household food security activity systems in Nyanyadzi Irrigation Scheme in the Manicaland Province of Zimbabwe
- Authors: Mukwambo, Robson
- Date: 2021-10-29
- Subjects: Active learning Zimbabwe Chimanimani District , Food security Zimbabwe Chimanimani District , Sustainable agriculture Zimbabwe Chimanimani District , Irrigation farming Zimbabwe Chimanimani District , Qualitative research , Cultural-historical activity theory (CHAT) , Nyanyadzi Irrigation Scheme
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192712 , vital:45253 , 10.21504/10962/192712
- Description: The study sought to mediate and examine expansive learning in the context of multidimensional complexities affecting household food security activity systems in Nyanyadzi Irrigation Scheme in Ward 8 of Chimanimani District in the Manicaland province of Zimbabwe. Therefore, the main foci of the study were to investigate how multidimensional complexities have come to be the way they are (historicizing) and how they enable or constrain learning of household food production. The study utilized Cultural Historical Activity Theory and the Expansive Learning Cycle (Engeström & Sannino, 2010) to examine and mediate collective learning in response to the multidimensional complexities and also to contribute to transforming the farmers’ activity systems towards more sustainable practices to ensure household food security. The study used a qualitative research approach, utilizing an insider formative intervention approach in a case study design in which Nyanyadzi irrigation scheme was the case study. I have adopted the insider formative interventionist role as a 3rd generation farmer, born and bred in Nyanyadzi area, and my family has been involved in the Nyanyadzi irrigation scheme for three generations. I see this as synergistic with the need for deep cultural understanding in CHAT research. However, this role also provided challenges for me to maintain a rigorous approach to the research in which I also reflexively review my own role and influence in the research process. Following CHAT expansive learning methodological guidance, data was generated through fifteen (15) face to face interviews with three generations of farmers in the scheme (historical ethnographic data); four focus group discussions (contemporary ethnographic data) and eight (8) sessions in a three (3) day change laboratory workshop (expansive learning data). Double stimulation and ‘mirror’ data was used to surface and prioritise responses to contradictions in the Change Laboratory Workshops (CLW), which is a methodology developed in and for CHAT research (ibid). The data was analysed using both inductive and abductive approaches and were conducted in a three-phased process focusing firstly on the history of the object, followed by current perspectives on the object of activity and lastly on transformations emerging in the object of activity via the expansive learning process. Cultural Historical Activity Theoretical tools informed activity system analysis and analysis of the history of the object and emerging contradictions; and the expansive learning cycle (ELP) process framework associated with and emergent from CHAT was used to analyse the emergence of transformative agency and expansion of the object. Four levels of contradictions were used to describe and explain the emergent contradictions namely, primary, secondary, tertiary and quaternary contradictions and are presented in this sequence as catalytic opportunities for expansive learning as proposed in CHAT. In addition, the four types of discursive manifestations of contradictions namely, dilemma, conflict, critical conflict and double bind were used to describe and explain the manifestations of contradictions in this study and their role in catalysing transformative agency. The concept of linguistic cues for discursive manifestations of contradictions was adopted and employed in the preliminary data analysis phase. In addition, the transformative agency expressions and zone of proximal development (ZPD) concept was applied in and to the CLW data to examine the learning pathways and to co-develop and expand farmers’ and other stakeholders’ transformative agency and ZPD respectively. I found myself as formative insider researcher having to take on a strong role as co-engaged researcher / participant in the irrigation scheme expansive learning process. The study concluded that the farmers’ activity system is the central activity system and it interacts with other activity systems on a partially shared object “improved crop production and marketing under irrigation scheme”. Through interactions with other neighbouring activity systems, the farmers have faced multidimensional complexities that constrain their ability to fully realise their object. These multidimensional complexities manifest in three critical contradictions as a critical conflict in leadership and management crisis; a dilemma and double bind in a lack of farmer education and training; and lastly, a dilemma and double bind in poor crop marketing. These multidimensional complexities have a historical account and they have evolved in complexity over time and I argue in the thesis that, a careful cultural-historicity of the object of activity and mediation of the situated learning can help to collectively come up with solutions to these multidimensional complexities. The study further concluded that despite these multidimensional complexities in the scheme, learning has been taking place and such learning was sometimes mediated through demonstrations as “learning by doing,” “seeing is believing” and the “winners and losers” concept. Furthermore, through the CLW process the farmers and other stakeholders’ cognitive horizons were expanded by the mirror data and double stimulation processes, and the expansive learning process developed their individual and collective transformative agency pathways and expanded their collective zone of proximal development. In this study I argue that there has been little said about collective learning in irrigation schemes and given the dearth of detail on such learning, it seems that this learning is either going unnoticed or is ignored. Hence, I further argued that the multidimensional complexities in irrigation schemes are both a stimulant for learning and provide a space (object) for collective learning, as was also shown by Baloi (2016). The study also shows that the collective learning potential in these irrigation schemes can be pro-actively mediated via expansive learning formative interventions in support of improved crop production and marketing for produce developed under irrigation in irrigation schemes such as the Nyanyadzi Irrigation scheme. Lastly, being an insider formative interventionist researcher in this study, with intergenerational engagement and perspective on the history of the object and integrational engagement with the transforming object, I became part of the intergenerational transformation of the irrigation scheme’s object. The intergenerational co-construction of the history of the object, coupled with the insider formative interventionist researcher approach opened up and allowed me as a current generation agent or actor to develop an in-depth understanding of the multidimensional nature and historicity of the object. This was crucial for opening up the transformative agency pathways. It also produced a responsibility for me as an insider formative interventionist researcher to carry the summative findings of the study back into the social context to widen the engagement and mediation of the transformation needed in the community. Overall not only does the study offer an intergenerational perspective on multidimensional complexities of the object and how this can generatively be mobilised via expansive learning into emerging transformative learning agency pathways, but it also offers a new vantage point on the role of the insider formative interventionist researcher. Through this, the study offers insight into how we as third generation members of the community can be brought closer to our communities through the application of our skills, thereby also offering a new type of engaged and rigorously framed and executed research with roots in our communities. As shown in this study, not only does this expand the knowledge and experience of those we engage with, but it also expands our own knowledge and expertise in order to be more able to contribute to both the challenges of our own communities but also that of other communities and situations similar to ours, and beyond these bounded contexts. The study’s contribution is both practical, but also methodological from this vantage point, especially in an African context where there is much critique of ‘outsider research’, yet little pro-active articulation of what insider (in this case, formative intervention) research may look like. , Thesis (PhD) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Mukwambo, Robson
- Date: 2021-10-29
- Subjects: Active learning Zimbabwe Chimanimani District , Food security Zimbabwe Chimanimani District , Sustainable agriculture Zimbabwe Chimanimani District , Irrigation farming Zimbabwe Chimanimani District , Qualitative research , Cultural-historical activity theory (CHAT) , Nyanyadzi Irrigation Scheme
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192712 , vital:45253 , 10.21504/10962/192712
- Description: The study sought to mediate and examine expansive learning in the context of multidimensional complexities affecting household food security activity systems in Nyanyadzi Irrigation Scheme in Ward 8 of Chimanimani District in the Manicaland province of Zimbabwe. Therefore, the main foci of the study were to investigate how multidimensional complexities have come to be the way they are (historicizing) and how they enable or constrain learning of household food production. The study utilized Cultural Historical Activity Theory and the Expansive Learning Cycle (Engeström & Sannino, 2010) to examine and mediate collective learning in response to the multidimensional complexities and also to contribute to transforming the farmers’ activity systems towards more sustainable practices to ensure household food security. The study used a qualitative research approach, utilizing an insider formative intervention approach in a case study design in which Nyanyadzi irrigation scheme was the case study. I have adopted the insider formative interventionist role as a 3rd generation farmer, born and bred in Nyanyadzi area, and my family has been involved in the Nyanyadzi irrigation scheme for three generations. I see this as synergistic with the need for deep cultural understanding in CHAT research. However, this role also provided challenges for me to maintain a rigorous approach to the research in which I also reflexively review my own role and influence in the research process. Following CHAT expansive learning methodological guidance, data was generated through fifteen (15) face to face interviews with three generations of farmers in the scheme (historical ethnographic data); four focus group discussions (contemporary ethnographic data) and eight (8) sessions in a three (3) day change laboratory workshop (expansive learning data). Double stimulation and ‘mirror’ data was used to surface and prioritise responses to contradictions in the Change Laboratory Workshops (CLW), which is a methodology developed in and for CHAT research (ibid). The data was analysed using both inductive and abductive approaches and were conducted in a three-phased process focusing firstly on the history of the object, followed by current perspectives on the object of activity and lastly on transformations emerging in the object of activity via the expansive learning process. Cultural Historical Activity Theoretical tools informed activity system analysis and analysis of the history of the object and emerging contradictions; and the expansive learning cycle (ELP) process framework associated with and emergent from CHAT was used to analyse the emergence of transformative agency and expansion of the object. Four levels of contradictions were used to describe and explain the emergent contradictions namely, primary, secondary, tertiary and quaternary contradictions and are presented in this sequence as catalytic opportunities for expansive learning as proposed in CHAT. In addition, the four types of discursive manifestations of contradictions namely, dilemma, conflict, critical conflict and double bind were used to describe and explain the manifestations of contradictions in this study and their role in catalysing transformative agency. The concept of linguistic cues for discursive manifestations of contradictions was adopted and employed in the preliminary data analysis phase. In addition, the transformative agency expressions and zone of proximal development (ZPD) concept was applied in and to the CLW data to examine the learning pathways and to co-develop and expand farmers’ and other stakeholders’ transformative agency and ZPD respectively. I found myself as formative insider researcher having to take on a strong role as co-engaged researcher / participant in the irrigation scheme expansive learning process. The study concluded that the farmers’ activity system is the central activity system and it interacts with other activity systems on a partially shared object “improved crop production and marketing under irrigation scheme”. Through interactions with other neighbouring activity systems, the farmers have faced multidimensional complexities that constrain their ability to fully realise their object. These multidimensional complexities manifest in three critical contradictions as a critical conflict in leadership and management crisis; a dilemma and double bind in a lack of farmer education and training; and lastly, a dilemma and double bind in poor crop marketing. These multidimensional complexities have a historical account and they have evolved in complexity over time and I argue in the thesis that, a careful cultural-historicity of the object of activity and mediation of the situated learning can help to collectively come up with solutions to these multidimensional complexities. The study further concluded that despite these multidimensional complexities in the scheme, learning has been taking place and such learning was sometimes mediated through demonstrations as “learning by doing,” “seeing is believing” and the “winners and losers” concept. Furthermore, through the CLW process the farmers and other stakeholders’ cognitive horizons were expanded by the mirror data and double stimulation processes, and the expansive learning process developed their individual and collective transformative agency pathways and expanded their collective zone of proximal development. In this study I argue that there has been little said about collective learning in irrigation schemes and given the dearth of detail on such learning, it seems that this learning is either going unnoticed or is ignored. Hence, I further argued that the multidimensional complexities in irrigation schemes are both a stimulant for learning and provide a space (object) for collective learning, as was also shown by Baloi (2016). The study also shows that the collective learning potential in these irrigation schemes can be pro-actively mediated via expansive learning formative interventions in support of improved crop production and marketing for produce developed under irrigation in irrigation schemes such as the Nyanyadzi Irrigation scheme. Lastly, being an insider formative interventionist researcher in this study, with intergenerational engagement and perspective on the history of the object and integrational engagement with the transforming object, I became part of the intergenerational transformation of the irrigation scheme’s object. The intergenerational co-construction of the history of the object, coupled with the insider formative interventionist researcher approach opened up and allowed me as a current generation agent or actor to develop an in-depth understanding of the multidimensional nature and historicity of the object. This was crucial for opening up the transformative agency pathways. It also produced a responsibility for me as an insider formative interventionist researcher to carry the summative findings of the study back into the social context to widen the engagement and mediation of the transformation needed in the community. Overall not only does the study offer an intergenerational perspective on multidimensional complexities of the object and how this can generatively be mobilised via expansive learning into emerging transformative learning agency pathways, but it also offers a new vantage point on the role of the insider formative interventionist researcher. Through this, the study offers insight into how we as third generation members of the community can be brought closer to our communities through the application of our skills, thereby also offering a new type of engaged and rigorously framed and executed research with roots in our communities. As shown in this study, not only does this expand the knowledge and experience of those we engage with, but it also expands our own knowledge and expertise in order to be more able to contribute to both the challenges of our own communities but also that of other communities and situations similar to ours, and beyond these bounded contexts. The study’s contribution is both practical, but also methodological from this vantage point, especially in an African context where there is much critique of ‘outsider research’, yet little pro-active articulation of what insider (in this case, formative intervention) research may look like. , Thesis (PhD) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
Mental Health Professionals’ Gender-Sensitivity and Responsiveness to the Genderqueer population in Substance Use Disorder Treatment: A Systematic Review
- Authors: Maseko, Moosa Lorenzo
- Date: 2021-10-29
- Subjects: Gender nonconformity , Substance abuse , Mental health personnel , Gender-nonconforming people Counseling of , Discrimination in mental health services , Joanna Briggs Institute’s systematic review method
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190133 , vital:44966
- Description: Background: The prevalence of Substance Use Disorders (SUDs) amongst the genderqueer population is a huge concern in the public mental health system. The genderqueer population’s help-seeking barriers have been attributed to SUD treatment centre’s questionable ability to be responsive to the unique mental health needs of genderqueer individuals. Aim: The aim of this study is to conduct a systematic review on mental healthcare workers‟ responsiveness and gender-sensitivity towards the genderqueer population in SUD treatment centres. Methods: Employing the Joanna Briggs Institute’s (JBIs) systematic review method, 25 qualitative articles were included in this study. A thematic analysis was used to examine the data. Results: The analysis revealed that SUD treatment centres are experienced as discriminatory and unreceptive by the genderqueer population due to several barriers. The barriers identified were structural, financial, personal, cultural and the use of a heterosexual framework to treat SUD which led to abuse, isolation, and stigma. Mental healthcare providers lack skills in working with genderqueer individuals as well as a lack of knowledge on genderqueer related needs. Lack of gender sensitivity affects genderqueer individuals in accessing SUD treatment centres and the progress they make. This magnified the need and importance of specialised gender-responsive and gender-sensitive training in working with genderqueer individuals. Twelve interventions to address the areas of difficulty were identified. , Thesis (MA) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Maseko, Moosa Lorenzo
- Date: 2021-10-29
- Subjects: Gender nonconformity , Substance abuse , Mental health personnel , Gender-nonconforming people Counseling of , Discrimination in mental health services , Joanna Briggs Institute’s systematic review method
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190133 , vital:44966
- Description: Background: The prevalence of Substance Use Disorders (SUDs) amongst the genderqueer population is a huge concern in the public mental health system. The genderqueer population’s help-seeking barriers have been attributed to SUD treatment centre’s questionable ability to be responsive to the unique mental health needs of genderqueer individuals. Aim: The aim of this study is to conduct a systematic review on mental healthcare workers‟ responsiveness and gender-sensitivity towards the genderqueer population in SUD treatment centres. Methods: Employing the Joanna Briggs Institute’s (JBIs) systematic review method, 25 qualitative articles were included in this study. A thematic analysis was used to examine the data. Results: The analysis revealed that SUD treatment centres are experienced as discriminatory and unreceptive by the genderqueer population due to several barriers. The barriers identified were structural, financial, personal, cultural and the use of a heterosexual framework to treat SUD which led to abuse, isolation, and stigma. Mental healthcare providers lack skills in working with genderqueer individuals as well as a lack of knowledge on genderqueer related needs. Lack of gender sensitivity affects genderqueer individuals in accessing SUD treatment centres and the progress they make. This magnified the need and importance of specialised gender-responsive and gender-sensitive training in working with genderqueer individuals. Twelve interventions to address the areas of difficulty were identified. , Thesis (MA) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10-29
Microalgal-bacterial flocs and extracellular polymeric substances for optimum function of integrated algal pond systems
- Authors: Jimoh, Taobat Adekilekun
- Date: 2021-10-29
- Subjects: Flocculation , Extracellular polymeric substances , Water Purification , Sewage Purification Anaerobic treatment , Integrated algae pond systems (IAPS) , Microalgal-bacterial flocs
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191214 , vital:45071 , 10.21504/10962/191214
- Description: Despite the dire state of sanitation infrastructures, water scarcity, and the dwindling reserve of natural resources due to ever-increasing population growth, implementation of a suitable technology that can provide a solution to all these issues continues to be ignored. The integrated algal pond system (IAPS) is a wastewater treatment technology that combines the processes of anaerobic digestion and photosynthetic oxygenation to achieve wastewater treatment and facilitate the recovery of treated water and resources in the form of biogas and microalgal-bacterial biomass. The natural process of bioflocculation through microalgal-bacterial mutualism and production of extracellular polymeric substances (EPS) in high rate algal oxidation ponds (HRAOPs) of an IAPS increases efficiency of wastewater treatment and potentially enhances harvestability and biomass recovery, which could contribute significantly to the successful establishment of a biorefinery. Using a 500 PE pilot-scale IAPS supplied domestic sewage coupled with laboratory experiments, this study investigated the importance and function of in situ EPS production and MaB-floc formation in HRAOP. A metagenomic study revealed the biological components of the biomass or mixed liquor suspended solids (MLSS) produced in HRAOP and showed that the suspended biomass is composed largely of eukaryotes that were dominated by the colonial microalgae Pseudopediastrum sp. and Desmodesmus sp., and a diverse range of prokaryotes including bacteria and cyanobacteria. Dominance, within the bacterial population, by a sulphur-oxidizing bacterium, Thiothrix which comprised up to 80% of the prokaryotes, coincided with a period of poor flocculation and was therefore rationalized to have contributed to bulking and poor biomass settleability. Otherwise, good flocs were formed in the MLSS with settleability up to 95% and, within 1 h. The formation of MaB-flocs appeared to be dependent on EPS concentration of the mixed liquor due to the observed positive correlation between soluble EPS (S-EPS), biomass concentration, and settleability. The contribution and role of MLSS components towards the formation and sustenance of MaB-flocs were further demonstrated in laboratory experiments using pure strains of microalgae, cyanobacteria, and bacteria. Results showed that pure cultures of dominant microalgae in MLSS, Pseudopediastrum sp. and Desmodesmus sp. achieved a rapid 92 and 75% settleability within 3 h. A self-flocculating filamentous cyanobacterium, Leptolyngbya strain ECCN 20BG was isolated, characterized, and shown to achieve 99% settleability within 5 min by forming large tightly aggregated flocs. In further experiments, this strain was found to improve the settleability of MLSS by an average of 20%. Bacterial strains identified as Bacillus strain ECCN 40b, Bacillus strain ECCN 41b, Planococcus strain ECCN 45b, and Exiguobacterium strain ECCN 46b were also observed to produce sticky EPS-like materials in pure cultures that could also contribute to the aggregation of cells in a mixed environment. Given these results, various factors and/or mechanisms that might enhance microbial aggregation and biomass recovery from HRAOP MLSS were identified in this study and include; (1) dominance by larger colonial microalgae prevents disintegration of MaB-flocs and enhances recovery of biomass from MLSS by gravity sedimentation, (2) presence of filamentous cyanobacteria species that can self-flocculate to form an interwoven network of filaments may play an important role in the structural stability and settleability of MaB-flocs in MLSS, and (3) production of EPS to form the matrix or scaffold whereon all microbial components aggregate to develop a microenvironment. Indeed, all forms of EPS, except for that produced by Bacillus strain ECCN 41b, showed bioflocculating property and were able to serve as flocculants for the recovery of Chlorella, an alga known for its poor settleability. A combination of biochemical analyses and FTIR spectroscopy revealed the importance of carbohydrate enrichment of these biopolymers. Carbohydrate concentration in all forms of EPS was between 12 and 41% suggesting that production of these compounds by microbes within the MLSS contributed to MaB-floc formation. EPS extracted from bulk MLSS and EPS produced by Bacillus strains possessed some surface-active properties that were comparable to Triton X-100, indicating potential application in bioremediation and recovery of oil from contaminated soil and water. In particular, EPS generated from Bacillus strain ECCN 41b displayed relatively distinct properties including the quantity produced (> 500 mg/L), increased viscosity, inability to flocculate microalgal cells, a rhamnolipid content of 32%, and a higher surface-activity. Based on these results, Bacillus strain ECCN 41b was rationalized to produce anionic EPS with potential application in metal or oil recovery. In addition to EPS production, the bacteria Planococcus strain ECCN 45b and Exiguobacterium strain ECCN 46b appeared pigmented. Based on partial characterization using UV/Vis spectrophotometry, thin-layer chromatography, FTIR, and NMR, the pigments produced by these two strains appeared to be identical and were tentatively identified as ketocarotenoids. This study successfully demonstrated the importance of EPS production and formation of MaB-flocs in the MLSS from HRAOP of an IAPS treating domestic sewage. It is evident that increased settleability of the biomass does contribute to the reported efficiency of wastewater treatment by IAPS and would reduce both total suspended solids (TSS) and chemical oxygen demand (COD). In addition, demonstration that this biomass contains products of value such as carotenoids and EPS with potential for commercial use strengthens the idea of using IAPS as a platform technology for innovation of the wastewater treatment process to a biorefinery. , Thesis (PhD) -- Faculty of Science, Institute for Environmental Biotechnology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Jimoh, Taobat Adekilekun
- Date: 2021-10-29
- Subjects: Flocculation , Extracellular polymeric substances , Water Purification , Sewage Purification Anaerobic treatment , Integrated algae pond systems (IAPS) , Microalgal-bacterial flocs
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191214 , vital:45071 , 10.21504/10962/191214
- Description: Despite the dire state of sanitation infrastructures, water scarcity, and the dwindling reserve of natural resources due to ever-increasing population growth, implementation of a suitable technology that can provide a solution to all these issues continues to be ignored. The integrated algal pond system (IAPS) is a wastewater treatment technology that combines the processes of anaerobic digestion and photosynthetic oxygenation to achieve wastewater treatment and facilitate the recovery of treated water and resources in the form of biogas and microalgal-bacterial biomass. The natural process of bioflocculation through microalgal-bacterial mutualism and production of extracellular polymeric substances (EPS) in high rate algal oxidation ponds (HRAOPs) of an IAPS increases efficiency of wastewater treatment and potentially enhances harvestability and biomass recovery, which could contribute significantly to the successful establishment of a biorefinery. Using a 500 PE pilot-scale IAPS supplied domestic sewage coupled with laboratory experiments, this study investigated the importance and function of in situ EPS production and MaB-floc formation in HRAOP. A metagenomic study revealed the biological components of the biomass or mixed liquor suspended solids (MLSS) produced in HRAOP and showed that the suspended biomass is composed largely of eukaryotes that were dominated by the colonial microalgae Pseudopediastrum sp. and Desmodesmus sp., and a diverse range of prokaryotes including bacteria and cyanobacteria. Dominance, within the bacterial population, by a sulphur-oxidizing bacterium, Thiothrix which comprised up to 80% of the prokaryotes, coincided with a period of poor flocculation and was therefore rationalized to have contributed to bulking and poor biomass settleability. Otherwise, good flocs were formed in the MLSS with settleability up to 95% and, within 1 h. The formation of MaB-flocs appeared to be dependent on EPS concentration of the mixed liquor due to the observed positive correlation between soluble EPS (S-EPS), biomass concentration, and settleability. The contribution and role of MLSS components towards the formation and sustenance of MaB-flocs were further demonstrated in laboratory experiments using pure strains of microalgae, cyanobacteria, and bacteria. Results showed that pure cultures of dominant microalgae in MLSS, Pseudopediastrum sp. and Desmodesmus sp. achieved a rapid 92 and 75% settleability within 3 h. A self-flocculating filamentous cyanobacterium, Leptolyngbya strain ECCN 20BG was isolated, characterized, and shown to achieve 99% settleability within 5 min by forming large tightly aggregated flocs. In further experiments, this strain was found to improve the settleability of MLSS by an average of 20%. Bacterial strains identified as Bacillus strain ECCN 40b, Bacillus strain ECCN 41b, Planococcus strain ECCN 45b, and Exiguobacterium strain ECCN 46b were also observed to produce sticky EPS-like materials in pure cultures that could also contribute to the aggregation of cells in a mixed environment. Given these results, various factors and/or mechanisms that might enhance microbial aggregation and biomass recovery from HRAOP MLSS were identified in this study and include; (1) dominance by larger colonial microalgae prevents disintegration of MaB-flocs and enhances recovery of biomass from MLSS by gravity sedimentation, (2) presence of filamentous cyanobacteria species that can self-flocculate to form an interwoven network of filaments may play an important role in the structural stability and settleability of MaB-flocs in MLSS, and (3) production of EPS to form the matrix or scaffold whereon all microbial components aggregate to develop a microenvironment. Indeed, all forms of EPS, except for that produced by Bacillus strain ECCN 41b, showed bioflocculating property and were able to serve as flocculants for the recovery of Chlorella, an alga known for its poor settleability. A combination of biochemical analyses and FTIR spectroscopy revealed the importance of carbohydrate enrichment of these biopolymers. Carbohydrate concentration in all forms of EPS was between 12 and 41% suggesting that production of these compounds by microbes within the MLSS contributed to MaB-floc formation. EPS extracted from bulk MLSS and EPS produced by Bacillus strains possessed some surface-active properties that were comparable to Triton X-100, indicating potential application in bioremediation and recovery of oil from contaminated soil and water. In particular, EPS generated from Bacillus strain ECCN 41b displayed relatively distinct properties including the quantity produced (> 500 mg/L), increased viscosity, inability to flocculate microalgal cells, a rhamnolipid content of 32%, and a higher surface-activity. Based on these results, Bacillus strain ECCN 41b was rationalized to produce anionic EPS with potential application in metal or oil recovery. In addition to EPS production, the bacteria Planococcus strain ECCN 45b and Exiguobacterium strain ECCN 46b appeared pigmented. Based on partial characterization using UV/Vis spectrophotometry, thin-layer chromatography, FTIR, and NMR, the pigments produced by these two strains appeared to be identical and were tentatively identified as ketocarotenoids. This study successfully demonstrated the importance of EPS production and formation of MaB-flocs in the MLSS from HRAOP of an IAPS treating domestic sewage. It is evident that increased settleability of the biomass does contribute to the reported efficiency of wastewater treatment by IAPS and would reduce both total suspended solids (TSS) and chemical oxygen demand (COD). In addition, demonstration that this biomass contains products of value such as carotenoids and EPS with potential for commercial use strengthens the idea of using IAPS as a platform technology for innovation of the wastewater treatment process to a biorefinery. , Thesis (PhD) -- Faculty of Science, Institute for Environmental Biotechnology, 2021
- Full Text:
- Date Issued: 2021-10-29
Mitigating salt accumulation in recycled brewery effluent through the integration of water treatment, agriculture and aquaculture
- Authors: Mabasa, Nyiko Charity
- Date: 2021-10-29
- Subjects: Brewery waste South Africa Eastern Cape , Recycling (Waste, etc.) South Africa Eastern Cape , Water reuse South Africa Eastern Cape , Irrigation South Africa Eastern Cape , Sewage Purification Anaerobic treatment , Constructed wetlands , Aquaculture
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191126 , vital:45063 , 10.21504/10962/191126
- Description: Water scarcity in South Africa, and globally, presents challenges for industries. It is imperative to develop responsible water use, such as recycling and reusing wastewater from food processing industries such as breweries. The Ibhayi Brewery (SAB Ltd) employs a combination of sustainable treatment processes that include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW) to treat brewery effluent on an experimental scale. The constituent concentrations of these experimentally treated effluents are within the ranges prescribed by local regulations to allow for potential downstream use in agriculture and aquaculture. However, the sodium content in this treated effluent, which originates from upstream cleaning agents and pH control at the onsite effluent treatment facility, is a constraint to the downstream use of brewery effluent. This study addresses the salt problem, by investigating the potential of either reducing/eliminating salt addition at source, or developing alternative techniques for downstream agriculture to mitigate the effects of salt accumulation caused by irrigation with brewery effluent. Four salt-tolerant test crops; Swiss chard (Beta vulgaris), saltbush (Atriplex nummularia), Salicornia meyeriana and sorghum (Sorghum bicolor), grew efficiently in brewery effluent irrigated soils but did not stop sodium accumulation in the growth medium. Swiss chard had the best growth with a wet biomass accumulation of 8,173 g m-2, due to the plant’s ability to tolerate saline conditions and continuous cropping. Crop rotation, to limit effects of nutrient depletion in soil, had no significant effect on plant growth suggesting soils were adequately able to provide micro-nutrients in the short-term. Prolonged irrigation with brewery effluent can lead to sodium accumulation in the soil, which was successfully controlled through the addition of soil amendments (gypsum and Trichoderma cultures). These reduced soil sodium from a potentially limiting level of 1,398 mg L-1 to the acceptable levels of 240 mg L-1 and 353 mg L-1 respectively, mainly through leaching. However only Trichoderma improved Swiss chard production to 11,238 g m-2. While crop rotation in this work did not contribute to mitigating the problem of salt accumulation, soil amended with Trichoderma appears to be a potential solution when brewery effluent is reused in agriculture. In an alternative to soil cultivation, CWs were trialled with no significant differences in the sodium concentration of brewery effluent treated along a 15 m lateral flow CW, which could be attributed to evapotranspiration. This was notably accompanied by a desirable 95.21% decrease in ammonia from inlet to outlet resulting in significant improvement in water quality for reuse in aquaculture where ammonia levels are important limiting constraints. While CWs remain a suitable brewery effluent treatment solution, this technology requires additional modelling and optimisation in order to mitigate the problem of salt accumulation in the reuse of treated brewery effluent in agriculture and aquaculture. This research demonstrates the baseline information for such modelling and optimisation. African catfish (Clarias gariepinus) grew in CW treated brewery effluent; however, this growth was moderate at 0.92% bw day-1, whereas Mozambique tilapia (Oreochromis mossambicus) were shown to be unsuited to growth in this system and lost weight with an average specific growth rate (SGR) of -0.98% bw day-1; and both fish species presenting with health related concerns. Hardy fish species such as African catfish can be cultured in brewery effluent, but with risk involved. This was a preliminary study to develop parameters for future dimensional analysis modelling to allow optimisation of the CW, based on nutrient removal rates obtained which will allow for improved downstream aquaculture by reducing or eliminating risks presented in this study. This work has also contributed to a foundation for the development of guidelines that use a risk-based approach for water use in aquaculture. Alternatives to the current in place cleaning agents were considered to mitigate the effects of salt accumulation. Sodium is introduced into the effluent via the use of sodium hydroxide and sodium chlorite for cleaning and disinfection in the brewery, as well as through effluent pH adjustment in the AD plant. The widespread use of outdated legacy cleaning systems and pH adjustment regimes is entrenched in the brewery standard operating procedures (SOP). A cost-benefit analysis (CBA) demonstrated that a change of cleaning and disinfecting regimes to hydrogen peroxide in the brewery, and magnesium hydroxide pH adjustment in the effluent treatment plant addresses the sodium issue upstream in the brewery practically eliminating sodium from the effluent. In addition, a life cycle analysis (LCA) was carried out to assess the environmental impacts associated with the alternative cleaning and pH adjustment scenarios. The LCA showed that electricity consumption during use phase of the chemicals for respective purposes, as well as their production activities were major contributors to the significant environmental impact categories that were assessed. The cleaning scenario employing the use of hydrogen peroxide for both cleaning and disinfection was found to be the most environmentally sustainable. This was attributed to the reduced number of chemicals used compared to the other cleaning scenarios. Dolomitic lime was the pH adjustment alternative with the lowest average environmental impact; but, however, had a higher impact on freshwater eutrophication which is of major concern if the effluent will be reused for irrigation. Magnesium hydroxide was therefore considered to be the better option as a sodium hydroxide alternative for pH adjustment. This mitigates salt accumulation, making treated brewery effluent suitable for reuse in high value downstream agriculture and aquaculture, while employing more environmentally sustainable technologies. Notably, this converts brewery effluent from a financial liability to Ibhayi Brewery, into a product containing water and nutrients that generate income, improve food security, and can create employment in downstream agriculture and aquaculture in a sustainable manner. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Mabasa, Nyiko Charity
- Date: 2021-10-29
- Subjects: Brewery waste South Africa Eastern Cape , Recycling (Waste, etc.) South Africa Eastern Cape , Water reuse South Africa Eastern Cape , Irrigation South Africa Eastern Cape , Sewage Purification Anaerobic treatment , Constructed wetlands , Aquaculture
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191126 , vital:45063 , 10.21504/10962/191126
- Description: Water scarcity in South Africa, and globally, presents challenges for industries. It is imperative to develop responsible water use, such as recycling and reusing wastewater from food processing industries such as breweries. The Ibhayi Brewery (SAB Ltd) employs a combination of sustainable treatment processes that include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW) to treat brewery effluent on an experimental scale. The constituent concentrations of these experimentally treated effluents are within the ranges prescribed by local regulations to allow for potential downstream use in agriculture and aquaculture. However, the sodium content in this treated effluent, which originates from upstream cleaning agents and pH control at the onsite effluent treatment facility, is a constraint to the downstream use of brewery effluent. This study addresses the salt problem, by investigating the potential of either reducing/eliminating salt addition at source, or developing alternative techniques for downstream agriculture to mitigate the effects of salt accumulation caused by irrigation with brewery effluent. Four salt-tolerant test crops; Swiss chard (Beta vulgaris), saltbush (Atriplex nummularia), Salicornia meyeriana and sorghum (Sorghum bicolor), grew efficiently in brewery effluent irrigated soils but did not stop sodium accumulation in the growth medium. Swiss chard had the best growth with a wet biomass accumulation of 8,173 g m-2, due to the plant’s ability to tolerate saline conditions and continuous cropping. Crop rotation, to limit effects of nutrient depletion in soil, had no significant effect on plant growth suggesting soils were adequately able to provide micro-nutrients in the short-term. Prolonged irrigation with brewery effluent can lead to sodium accumulation in the soil, which was successfully controlled through the addition of soil amendments (gypsum and Trichoderma cultures). These reduced soil sodium from a potentially limiting level of 1,398 mg L-1 to the acceptable levels of 240 mg L-1 and 353 mg L-1 respectively, mainly through leaching. However only Trichoderma improved Swiss chard production to 11,238 g m-2. While crop rotation in this work did not contribute to mitigating the problem of salt accumulation, soil amended with Trichoderma appears to be a potential solution when brewery effluent is reused in agriculture. In an alternative to soil cultivation, CWs were trialled with no significant differences in the sodium concentration of brewery effluent treated along a 15 m lateral flow CW, which could be attributed to evapotranspiration. This was notably accompanied by a desirable 95.21% decrease in ammonia from inlet to outlet resulting in significant improvement in water quality for reuse in aquaculture where ammonia levels are important limiting constraints. While CWs remain a suitable brewery effluent treatment solution, this technology requires additional modelling and optimisation in order to mitigate the problem of salt accumulation in the reuse of treated brewery effluent in agriculture and aquaculture. This research demonstrates the baseline information for such modelling and optimisation. African catfish (Clarias gariepinus) grew in CW treated brewery effluent; however, this growth was moderate at 0.92% bw day-1, whereas Mozambique tilapia (Oreochromis mossambicus) were shown to be unsuited to growth in this system and lost weight with an average specific growth rate (SGR) of -0.98% bw day-1; and both fish species presenting with health related concerns. Hardy fish species such as African catfish can be cultured in brewery effluent, but with risk involved. This was a preliminary study to develop parameters for future dimensional analysis modelling to allow optimisation of the CW, based on nutrient removal rates obtained which will allow for improved downstream aquaculture by reducing or eliminating risks presented in this study. This work has also contributed to a foundation for the development of guidelines that use a risk-based approach for water use in aquaculture. Alternatives to the current in place cleaning agents were considered to mitigate the effects of salt accumulation. Sodium is introduced into the effluent via the use of sodium hydroxide and sodium chlorite for cleaning and disinfection in the brewery, as well as through effluent pH adjustment in the AD plant. The widespread use of outdated legacy cleaning systems and pH adjustment regimes is entrenched in the brewery standard operating procedures (SOP). A cost-benefit analysis (CBA) demonstrated that a change of cleaning and disinfecting regimes to hydrogen peroxide in the brewery, and magnesium hydroxide pH adjustment in the effluent treatment plant addresses the sodium issue upstream in the brewery practically eliminating sodium from the effluent. In addition, a life cycle analysis (LCA) was carried out to assess the environmental impacts associated with the alternative cleaning and pH adjustment scenarios. The LCA showed that electricity consumption during use phase of the chemicals for respective purposes, as well as their production activities were major contributors to the significant environmental impact categories that were assessed. The cleaning scenario employing the use of hydrogen peroxide for both cleaning and disinfection was found to be the most environmentally sustainable. This was attributed to the reduced number of chemicals used compared to the other cleaning scenarios. Dolomitic lime was the pH adjustment alternative with the lowest average environmental impact; but, however, had a higher impact on freshwater eutrophication which is of major concern if the effluent will be reused for irrigation. Magnesium hydroxide was therefore considered to be the better option as a sodium hydroxide alternative for pH adjustment. This mitigates salt accumulation, making treated brewery effluent suitable for reuse in high value downstream agriculture and aquaculture, while employing more environmentally sustainable technologies. Notably, this converts brewery effluent from a financial liability to Ibhayi Brewery, into a product containing water and nutrients that generate income, improve food security, and can create employment in downstream agriculture and aquaculture in a sustainable manner. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Modifcations to gravitational waves due to matter shells
- Authors: Naidoo, Monogaran
- Date: 2021-10-29
- Subjects: Gravitational waves , General relativity (Physics) , Einstein field equations , Cosmology , Matter shells
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191118 , vital:45062 , 10.21504/10962/191119
- Description: As detections of gravitational waves (GWs) mount, the need to investigate various effects on the propagation of these waves from the time of emission until detection also grows. We investigate how a thin low density dust shell surrounding a gravitational wave source affects the propagation of GWs. The Bondi-Sachs (BS) formalism for the Einstein equations is used for the problem of a gravitational wave (GW) source surrounded by a spherical dust shell. Using linearised perturbation theory, we and the geometry of the regions exterior to, interior to and within the shell. We and that the dust shell causes the gravitational wave to be modified both in magnitude and phase, but without any energy being transferred to or from the dust. This finding is novel. In the context of cosmology, apart from the gravitational redshift, the effects are too small to be measurable; but the effect would be measurable if a GW event were to occur with a source surrounded by a massive shell and with the radius of the shell and the wavelength of the GWs of the same order. We extended our investigation to astrophysical scenarios such as binary black hole (BBH) mergers, binary neutron star (BNS) mergers, and core collapse supernovae (CCSNe). In these scenarios, instead of a monochromatic GW source, as we used in our initial investigation, we consider burst-like GW sources. The thin density shell approach is modified to include thick shells by considering concentric thin shells and integrating. Solutions are then found for these burst-like GW sources using Fourier transforms. We show that GW echoes that are claimed to be present in the Laser Interferometer Gravitational-Wave Observatory (LIGO) data of certain events, could not have been caused by a matter shell. We do and, however, that matter shells surrounding BBH mergers, BNS mergers, and CCSNe could make modifications of order a few percent to a GW signal. These modifications are expected to be measurable in GW data with current detectors if the event is close enough and at a detectable frequency; or in future detectors with increased frequency range and amplitude sensitivity. Substantial use is made of computer algebra in these investigations. In setting the scene for our investigations, we trace the evolution of general relativity (GR) from Einstein's postulation in 1915 to vindication of his theory with the confirmation of the existence of GWs a century later. We discuss the implications of our results to current and future considerations. Calculations of GWs, both analytical and numerical, have normally assumed their propagation from source to a detector on Earth in a vacuum spacetime, and so discounted the effect of intervening matter. As we enter an era of precision GW measurements, it becomes important to quantify any effects due to propagation of GWs through a non-vacuum spacetime Observational confirmation of the modification effect that we and in astrophysical scenarios involving black holes (BHs), neutron stars (NSs) and CCSNe, would also enhance our understanding of the details of the physics of these bodies. , Thesis (PhD) -- Faculty of Science, Mathematics (Pure and Applied), 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Naidoo, Monogaran
- Date: 2021-10-29
- Subjects: Gravitational waves , General relativity (Physics) , Einstein field equations , Cosmology , Matter shells
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191118 , vital:45062 , 10.21504/10962/191119
- Description: As detections of gravitational waves (GWs) mount, the need to investigate various effects on the propagation of these waves from the time of emission until detection also grows. We investigate how a thin low density dust shell surrounding a gravitational wave source affects the propagation of GWs. The Bondi-Sachs (BS) formalism for the Einstein equations is used for the problem of a gravitational wave (GW) source surrounded by a spherical dust shell. Using linearised perturbation theory, we and the geometry of the regions exterior to, interior to and within the shell. We and that the dust shell causes the gravitational wave to be modified both in magnitude and phase, but without any energy being transferred to or from the dust. This finding is novel. In the context of cosmology, apart from the gravitational redshift, the effects are too small to be measurable; but the effect would be measurable if a GW event were to occur with a source surrounded by a massive shell and with the radius of the shell and the wavelength of the GWs of the same order. We extended our investigation to astrophysical scenarios such as binary black hole (BBH) mergers, binary neutron star (BNS) mergers, and core collapse supernovae (CCSNe). In these scenarios, instead of a monochromatic GW source, as we used in our initial investigation, we consider burst-like GW sources. The thin density shell approach is modified to include thick shells by considering concentric thin shells and integrating. Solutions are then found for these burst-like GW sources using Fourier transforms. We show that GW echoes that are claimed to be present in the Laser Interferometer Gravitational-Wave Observatory (LIGO) data of certain events, could not have been caused by a matter shell. We do and, however, that matter shells surrounding BBH mergers, BNS mergers, and CCSNe could make modifications of order a few percent to a GW signal. These modifications are expected to be measurable in GW data with current detectors if the event is close enough and at a detectable frequency; or in future detectors with increased frequency range and amplitude sensitivity. Substantial use is made of computer algebra in these investigations. In setting the scene for our investigations, we trace the evolution of general relativity (GR) from Einstein's postulation in 1915 to vindication of his theory with the confirmation of the existence of GWs a century later. We discuss the implications of our results to current and future considerations. Calculations of GWs, both analytical and numerical, have normally assumed their propagation from source to a detector on Earth in a vacuum spacetime, and so discounted the effect of intervening matter. As we enter an era of precision GW measurements, it becomes important to quantify any effects due to propagation of GWs through a non-vacuum spacetime Observational confirmation of the modification effect that we and in astrophysical scenarios involving black holes (BHs), neutron stars (NSs) and CCSNe, would also enhance our understanding of the details of the physics of these bodies. , Thesis (PhD) -- Faculty of Science, Mathematics (Pure and Applied), 2021
- Full Text:
- Date Issued: 2021-10-29