Unpacking the link between adaptive capacity, assets and responses of rural livelihoods facing multiple stressors in the Eastern Cape
- Dalu, Mwazvita Tapiwa Beatrice
- Authors: Dalu, Mwazvita Tapiwa Beatrice
- Date: 2020
- Language: English
- Type: thesis , text , Doctoral , Ph.D
- Identifier: http://hdl.handle.net/10962/147103 , vital:38593 , doi:10.21504/10962/147103
- Description: Thesis (PhD.)--Rhodes University, Faculty of Science, Environmental Science, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Dalu, Mwazvita Tapiwa Beatrice
- Date: 2020
- Language: English
- Type: thesis , text , Doctoral , Ph.D
- Identifier: http://hdl.handle.net/10962/147103 , vital:38593 , doi:10.21504/10962/147103
- Description: Thesis (PhD.)--Rhodes University, Faculty of Science, Environmental Science, 2020.
- Full Text:
- Date Issued: 2020
Ritualised discourse practices of feedback in a university foundation programme: a critical investigation
- Authors: Richardson, Amy
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164955 , vital:41187
- Description: In order for students to become true members of academic communities of practice they need epistemological access, including guidance on central institutional knowledge-producing processes and mastery of key academic literacy practices. A powerful source of guidance is marker feedback. Drawing on key insights from the New Literacy Studies and taking up the mandate of Critical Ethnography to improve the status quo, this thesis reports on the feedback practices in a university foundation programme. The findings are based on three micro-case studies compiled and analysed by means of methods drawn from Ethnography, Sociolinguistics and Critical Analysis in conjunction with an expanded, multimodal, APPRAISAL analysis, including adjusted categories and the author’s own feedback typologies. Two major arguments emerge: the feedback provided amounts to a set of ritualised discourse practices and its effects can be likened to the product of the children’s game of Head-body-tail. Consequently, feedback conventions are opaque and, potentially, impede epistemological access. They further entrench five sets of ideologies: (1) Students must master basic English literacy before they are coached in more complex issues such as argumentation; an assumption which leads to differential socialisation. (2) There is a single set of literacy practices that is rewarded. (3) Students have different levels of authorial authority depending on their language abilities. (4) ‘Middle students’ may benefit the most from feedback. (5) Specific comments are preferred over general ones. Analysis of feedback, furthermore, shows that markers’ frames of reference shape their pedagogy and that draft and final versions of work may be framed differently by markers. These findings require a response and, in order to facilitate epistemological access, suggestions are made for improved marker training based on the problematisation of the ritual involved in marking students’ work in this university foundation programme. , Thesis (MA)--Rhodes University, Faculty of Humanities, Linguistics, 2012
- Full Text:
- Date Issued: 2012
- Authors: Richardson, Amy
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164955 , vital:41187
- Description: In order for students to become true members of academic communities of practice they need epistemological access, including guidance on central institutional knowledge-producing processes and mastery of key academic literacy practices. A powerful source of guidance is marker feedback. Drawing on key insights from the New Literacy Studies and taking up the mandate of Critical Ethnography to improve the status quo, this thesis reports on the feedback practices in a university foundation programme. The findings are based on three micro-case studies compiled and analysed by means of methods drawn from Ethnography, Sociolinguistics and Critical Analysis in conjunction with an expanded, multimodal, APPRAISAL analysis, including adjusted categories and the author’s own feedback typologies. Two major arguments emerge: the feedback provided amounts to a set of ritualised discourse practices and its effects can be likened to the product of the children’s game of Head-body-tail. Consequently, feedback conventions are opaque and, potentially, impede epistemological access. They further entrench five sets of ideologies: (1) Students must master basic English literacy before they are coached in more complex issues such as argumentation; an assumption which leads to differential socialisation. (2) There is a single set of literacy practices that is rewarded. (3) Students have different levels of authorial authority depending on their language abilities. (4) ‘Middle students’ may benefit the most from feedback. (5) Specific comments are preferred over general ones. Analysis of feedback, furthermore, shows that markers’ frames of reference shape their pedagogy and that draft and final versions of work may be framed differently by markers. These findings require a response and, in order to facilitate epistemological access, suggestions are made for improved marker training based on the problematisation of the ritual involved in marking students’ work in this university foundation programme. , Thesis (MA)--Rhodes University, Faculty of Humanities, Linguistics, 2012
- Full Text:
- Date Issued: 2012
In My Flesh : Fabricating the Bulimic Body
- Authors: Hodgson, Ashley
- Date: 2021-04
- Subjects: Bulimia , Human body -- Social aspects , Human figure in art , Diseases in art , Art therapy
- Language: English
- Type: thesis , text , Masters , MFA
- Identifier: http://hdl.handle.net/10962/177317 , vital:42809
- Description: My MFA exhibition In My Flesh, explores my own personal experience of an eating disorder: bulimia nervosa, through the medium of sculpture and installation. Situated in the Fine Art Sculpture and Painting building on Rhodes University campus, this practical submission takes the form of a multi-sensory installation depicting the fleshy interior of a bulimic body. The sculptural works that make up the installation resemble enlarged bodily forms and cavities, namely the mouth; the oesophagus, the stomach; the intestines; and the flesh. These anatomical forms are made from fabric which has been melted, manipulated, and stained using food and other synthetic dyes. The arrangement of the sculptural components (parts of the body affected by bulimia) does not mirror the human body exactly, and their intentionally disordered placement creates a feeling of dis-ease and disturbance for the participant experiencing the installation. This mini-thesis, In My Flesh: Fabricating the Bulimic Body, unpacks the visual, tactile and audio elements of this practice as research submission as they relate to my interest in bodily boundaries, corporeal traces and material extensions. I look at these themes as they translate into installation, and discuss the way in which bulimia is experienced, theorised and represented. I position my work in relation to the concept of the abject as proposed by Julia Kristeva, and visually analyse artworks by Mona Hatoum, Heidi Bucher and Ernesto Neto who make use of immersive installation strategies that resonate with my own practice. This supporting document considers the three conceptual elements informing my installation: embodiment, space, and materiality. In the first chapter of this document: Embodying the Bulimic Body, I address bulimia as less open to visual interpretations than other eating disorders because of its secretive and hidden nature. I go on to frame the illness in relation to theories around bodily boundaries and abjection and argue that bulimia epitomises abjection. In Chapter Two: Architecture of the Bulimic Body I engage with the idea of architectural structures as having anatomic features. I interrogate how the body moves through space, leaving traces of itself behind. Chapter Three: Fabricating the Bulimic Body concentrates on the main medium used in In My Flesh: fabric. In my discussion of this material, I unpack its metaphoric and symbolic qualities, as well as its personal resonance with my own lived experience. , Thesis (MFA) -- Faculty of Humanities, Fine Art, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Hodgson, Ashley
- Date: 2021-04
- Subjects: Bulimia , Human body -- Social aspects , Human figure in art , Diseases in art , Art therapy
- Language: English
- Type: thesis , text , Masters , MFA
- Identifier: http://hdl.handle.net/10962/177317 , vital:42809
- Description: My MFA exhibition In My Flesh, explores my own personal experience of an eating disorder: bulimia nervosa, through the medium of sculpture and installation. Situated in the Fine Art Sculpture and Painting building on Rhodes University campus, this practical submission takes the form of a multi-sensory installation depicting the fleshy interior of a bulimic body. The sculptural works that make up the installation resemble enlarged bodily forms and cavities, namely the mouth; the oesophagus, the stomach; the intestines; and the flesh. These anatomical forms are made from fabric which has been melted, manipulated, and stained using food and other synthetic dyes. The arrangement of the sculptural components (parts of the body affected by bulimia) does not mirror the human body exactly, and their intentionally disordered placement creates a feeling of dis-ease and disturbance for the participant experiencing the installation. This mini-thesis, In My Flesh: Fabricating the Bulimic Body, unpacks the visual, tactile and audio elements of this practice as research submission as they relate to my interest in bodily boundaries, corporeal traces and material extensions. I look at these themes as they translate into installation, and discuss the way in which bulimia is experienced, theorised and represented. I position my work in relation to the concept of the abject as proposed by Julia Kristeva, and visually analyse artworks by Mona Hatoum, Heidi Bucher and Ernesto Neto who make use of immersive installation strategies that resonate with my own practice. This supporting document considers the three conceptual elements informing my installation: embodiment, space, and materiality. In the first chapter of this document: Embodying the Bulimic Body, I address bulimia as less open to visual interpretations than other eating disorders because of its secretive and hidden nature. I go on to frame the illness in relation to theories around bodily boundaries and abjection and argue that bulimia epitomises abjection. In Chapter Two: Architecture of the Bulimic Body I engage with the idea of architectural structures as having anatomic features. I interrogate how the body moves through space, leaving traces of itself behind. Chapter Three: Fabricating the Bulimic Body concentrates on the main medium used in In My Flesh: fabric. In my discussion of this material, I unpack its metaphoric and symbolic qualities, as well as its personal resonance with my own lived experience. , Thesis (MFA) -- Faculty of Humanities, Fine Art, 2021
- Full Text:
- Date Issued: 2021-04
Analysis of the regulation of HSP90α expression upon differentiation of C2C12 cells
- Authors: Holm, Nathan Christopher
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163318 , vital:41028
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Holm, Nathan Christopher
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163318 , vital:41028
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Date Issued: 2020
Anisotropic copper oxide nanorods decorated with gold and palladium nanoparticles and their enzymatic properties
- Authors: Sicwetsha, Simbongile
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178547 , vital:42949
- Description: Access restricted until April 2023. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Sicwetsha, Simbongile
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178547 , vital:42949
- Description: Access restricted until April 2023. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
An investigation into the current state of web based cryptominers and cryptojacking
- Authors: Len, Robert
- Date: 2021-04
- Subjects: Cryptocurrencies , Malware (Computer software) , Computer networks -- Security measures , Computer networks -- Monitoring , Cryptomining , Coinhive , Cryptojacking
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178248 , vital:42924
- Description: The aim of this research was to conduct a review of the current state and extent of surreptitious crypto mining software and its prevalence as a means for income generation. Income is generated through the use of a viewer's browser to execute custom JavaScript code to mine cryptocurrencies such as Monero and Bitcoin. The research aimed to measure the prevalence of illicit mining scripts being utilised for “in-browser" cryptojacking while further analysing the ecosystems that support the cryptomining environment. The extent of the research covers aspects such as the content (or type) of the sites hosting malicious “in-browser" cryptomining software as well as the occurrences of currencies utilised in the cryptographic mining and the analysis of cryptographic mining code samples. This research aims to compare the results of previous work with the current state of affairs since the closure of Coinhive in March 2018. Coinhive were at the time the market leader in such web based mining services. Beyond the analysis of the prevalence of cryptomining on the web today, research into the methodologies and techniques used to detect and counteract cryptomining are also conducted. This includes the most recent developments in malicious JavaScript de-obfuscation as well as cryptomining signature creation and detection. Methodologies for heuristic JavaScript behaviour identification and subsequent identification of potential malicious out-liars are also included within the research of the countermeasure analysis. The research revealed that although no longer functional, Coinhive remained as the most prevalent script being used for “in-browser" cryptomining services. While remaining the most prevalent, there was however a significant decline in overall occurrences compared to when coinhive.com was operational. Analysis of the ecosystem hosting \in-browser" mining websites was found to be distributed both geographically as well as in terms of domain categorisations. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Len, Robert
- Date: 2021-04
- Subjects: Cryptocurrencies , Malware (Computer software) , Computer networks -- Security measures , Computer networks -- Monitoring , Cryptomining , Coinhive , Cryptojacking
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178248 , vital:42924
- Description: The aim of this research was to conduct a review of the current state and extent of surreptitious crypto mining software and its prevalence as a means for income generation. Income is generated through the use of a viewer's browser to execute custom JavaScript code to mine cryptocurrencies such as Monero and Bitcoin. The research aimed to measure the prevalence of illicit mining scripts being utilised for “in-browser" cryptojacking while further analysing the ecosystems that support the cryptomining environment. The extent of the research covers aspects such as the content (or type) of the sites hosting malicious “in-browser" cryptomining software as well as the occurrences of currencies utilised in the cryptographic mining and the analysis of cryptographic mining code samples. This research aims to compare the results of previous work with the current state of affairs since the closure of Coinhive in March 2018. Coinhive were at the time the market leader in such web based mining services. Beyond the analysis of the prevalence of cryptomining on the web today, research into the methodologies and techniques used to detect and counteract cryptomining are also conducted. This includes the most recent developments in malicious JavaScript de-obfuscation as well as cryptomining signature creation and detection. Methodologies for heuristic JavaScript behaviour identification and subsequent identification of potential malicious out-liars are also included within the research of the countermeasure analysis. The research revealed that although no longer functional, Coinhive remained as the most prevalent script being used for “in-browser" cryptomining services. While remaining the most prevalent, there was however a significant decline in overall occurrences compared to when coinhive.com was operational. Analysis of the ecosystem hosting \in-browser" mining websites was found to be distributed both geographically as well as in terms of domain categorisations. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-04
The effect of sectoral foreign direct investment on sectoral growth and sectoral employment in South Africa
- Authors: Paul, Bernice Nicole
- Date: 2021-04
- Subjects: Investments, Foreign -- South Africa , South Africa -- Economic conditions -- 1991- , South Africa -- Economic policy , Gross domestic product -- South Africa , UNCTAD-ICTSD Project on IPRs and Sustainable Development , Unemployment -- South Africa
- Language: English
- Type: thesis , text , Master , MCom
- Identifier: http://hdl.handle.net/10962/177964 , vital:42894
- Description: Over several decades past, developing countries have received increased amounts of Foreign Direct Investment (FDI). This form of investment has been welcomed because of the perceived benefits attached to it. FDI is seen as an important driver of economic development for many nations. For South Africa specifically, GDP growth rates have remained less than required, unemployment rates have reached staggering levels, poverty and inequality levels are increasing and the list goes on. Considering the perceived benefits of FDI, one may argue that FDI can play a crucial role in reducing the mentioned challenges facing the nation, however, only if directed to initiatives contributing to growth and employment. The 2015 Investment Policy Framework for Sustainable Development includes an action menu promoting investment in sectors relating to the achievement of the Sustainable Development Goals (SDGs). Therefore, this study is aimed at investigating the relationship between sector FDI and sector growth in addition to investigating the effect of sector FDI on sector employment over the period 2000Q1 to 2016Q4 for six of South Africa’s economic sectors. The reason for such a study is based on the premise that developing nations such as South Africa lack sound trade and industrial policies favorable to foreign investors. This then leads to the nation failing to attract higher volumes of FDI which could be used to address structural challenges facing the country. It is therefore important to identify sectors in which FDI has resulted in growth and employment so that when policies are considered, the right FDI is targeted. A comprehensive review of existing theoretical and empirical literature showed that FDI does result in economic growth for developed and developing countries, although FDI crowds out domestic investment in the short run. Literature on the effect of FDI on employment showed diverse effects. Some studies found FDI to increase employment overall, other studies found FDI to increase employment only during periods of restructuring and some studies found FDI to result in job losses. For South African sectors, the present study finds that the financial services sector receives the highest volume of South African FDI, followed by the mining and quarrying sector and the manufacturing, however, FDI in all six sectors under study is associated with increased growth and employment. This finding suggests that the financial services sector has received increased volumes of FDI as a result of financialization of the South African economy. It is this increased FDI in the financial services sector that is directed to income redistribution from the real sector to the finance sector. This study employed econometric techniques and methods of analysis to investigate the relationship between sector FDI and sector growth, and the effect of sector FDI on sector employment. Panel cointegration tests were conducted for all six sectors included in the study to establish if long run equilibrium relationships exist among integrated variables. The Johansen-Fisher panel cointegration test revealed that there is evidence of cointegration in four of the six sectors. Since cointegration was established, the study proceeded to perform the Dumitrescu-Hurlin panel causality analysis and estimate a Panel Vector Error Correction Model (VECM). Results from the causality analysis found a unidirectional causality relationship between FDI and GDP growth, while the panel VECM found FDI to have a significant effect on growth in all sectors. The Seemingly Unrelated Regression (SUR) model employed to investigate the effect of FDI on employment found FDI to have an insignificant effect on employment in all sectors included, although the signs of the coefficients suggest that FDI is associated with increased employment and rising wages is associated with increased productivity growth. Since this study finds that FDI is associated with increased GDP growth in all six sectors under study, policy makers should devise strategies to attract FDI in sectors such as the transportation, storage and communication sector and the electricity, gas and water sector as FDI in these sectors are associated with increased growth however, they receive very low levels of FDI. There are a number of reasons for this, therefore, government institutions and policy makers should investigate the reasons for these low levels of FDI inflows into these sectors so that they can devise further strategies to address these reasons and perhaps attract higher levels of FDI into these sectors. Spillover benefits play a major role in host nations participating in FDI therefore, prior to entering into bilateral treaty agreements, policy makers should ensure that foreign investors are compelled to create jobs, offer training and qualifications etc. through their investments so that some of the SDGs can be achieved. Additionally, this study finds a positive, statistically insignificant relationship between FDI and employment. FDI may not have a significant relationship on employment due to jobless growth and capital-intensive growth rather than labor-intensive growth. Such a situation calls for government intervention. Skills shortage is a rising problem in South Africa; therefore, investors choose to employ advanced technologies rather than people. Under such circumstances, governments are encouraged to invest resources into skills development so that human capital are not completely replaced by technology. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Paul, Bernice Nicole
- Date: 2021-04
- Subjects: Investments, Foreign -- South Africa , South Africa -- Economic conditions -- 1991- , South Africa -- Economic policy , Gross domestic product -- South Africa , UNCTAD-ICTSD Project on IPRs and Sustainable Development , Unemployment -- South Africa
- Language: English
- Type: thesis , text , Master , MCom
- Identifier: http://hdl.handle.net/10962/177964 , vital:42894
- Description: Over several decades past, developing countries have received increased amounts of Foreign Direct Investment (FDI). This form of investment has been welcomed because of the perceived benefits attached to it. FDI is seen as an important driver of economic development for many nations. For South Africa specifically, GDP growth rates have remained less than required, unemployment rates have reached staggering levels, poverty and inequality levels are increasing and the list goes on. Considering the perceived benefits of FDI, one may argue that FDI can play a crucial role in reducing the mentioned challenges facing the nation, however, only if directed to initiatives contributing to growth and employment. The 2015 Investment Policy Framework for Sustainable Development includes an action menu promoting investment in sectors relating to the achievement of the Sustainable Development Goals (SDGs). Therefore, this study is aimed at investigating the relationship between sector FDI and sector growth in addition to investigating the effect of sector FDI on sector employment over the period 2000Q1 to 2016Q4 for six of South Africa’s economic sectors. The reason for such a study is based on the premise that developing nations such as South Africa lack sound trade and industrial policies favorable to foreign investors. This then leads to the nation failing to attract higher volumes of FDI which could be used to address structural challenges facing the country. It is therefore important to identify sectors in which FDI has resulted in growth and employment so that when policies are considered, the right FDI is targeted. A comprehensive review of existing theoretical and empirical literature showed that FDI does result in economic growth for developed and developing countries, although FDI crowds out domestic investment in the short run. Literature on the effect of FDI on employment showed diverse effects. Some studies found FDI to increase employment overall, other studies found FDI to increase employment only during periods of restructuring and some studies found FDI to result in job losses. For South African sectors, the present study finds that the financial services sector receives the highest volume of South African FDI, followed by the mining and quarrying sector and the manufacturing, however, FDI in all six sectors under study is associated with increased growth and employment. This finding suggests that the financial services sector has received increased volumes of FDI as a result of financialization of the South African economy. It is this increased FDI in the financial services sector that is directed to income redistribution from the real sector to the finance sector. This study employed econometric techniques and methods of analysis to investigate the relationship between sector FDI and sector growth, and the effect of sector FDI on sector employment. Panel cointegration tests were conducted for all six sectors included in the study to establish if long run equilibrium relationships exist among integrated variables. The Johansen-Fisher panel cointegration test revealed that there is evidence of cointegration in four of the six sectors. Since cointegration was established, the study proceeded to perform the Dumitrescu-Hurlin panel causality analysis and estimate a Panel Vector Error Correction Model (VECM). Results from the causality analysis found a unidirectional causality relationship between FDI and GDP growth, while the panel VECM found FDI to have a significant effect on growth in all sectors. The Seemingly Unrelated Regression (SUR) model employed to investigate the effect of FDI on employment found FDI to have an insignificant effect on employment in all sectors included, although the signs of the coefficients suggest that FDI is associated with increased employment and rising wages is associated with increased productivity growth. Since this study finds that FDI is associated with increased GDP growth in all six sectors under study, policy makers should devise strategies to attract FDI in sectors such as the transportation, storage and communication sector and the electricity, gas and water sector as FDI in these sectors are associated with increased growth however, they receive very low levels of FDI. There are a number of reasons for this, therefore, government institutions and policy makers should investigate the reasons for these low levels of FDI inflows into these sectors so that they can devise further strategies to address these reasons and perhaps attract higher levels of FDI into these sectors. Spillover benefits play a major role in host nations participating in FDI therefore, prior to entering into bilateral treaty agreements, policy makers should ensure that foreign investors are compelled to create jobs, offer training and qualifications etc. through their investments so that some of the SDGs can be achieved. Additionally, this study finds a positive, statistically insignificant relationship between FDI and employment. FDI may not have a significant relationship on employment due to jobless growth and capital-intensive growth rather than labor-intensive growth. Such a situation calls for government intervention. Skills shortage is a rising problem in South Africa; therefore, investors choose to employ advanced technologies rather than people. Under such circumstances, governments are encouraged to invest resources into skills development so that human capital are not completely replaced by technology. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2021
- Full Text:
- Date Issued: 2021-04
BODIPY dyes for use in nonlinear optics and optical sensing
- Authors: Kubheka, Gugu Patience
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163352 , vital:41032 , doi:10.21504/10962/163352
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Department of Chemistry, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Kubheka, Gugu Patience
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163352 , vital:41032 , doi:10.21504/10962/163352
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Department of Chemistry, 2020.
- Full Text:
- Date Issued: 2020
An evaluation of synergistic interactions between feruloyl esterases and xylanases during the hydrolysis of various pre-treated agricultural residues
- Authors: Mkabayi, Lithalethu
- Date: 2021-04
- Subjects: Esterases , Xylanases , Hydrolysis , Agricultural wastes -- Recycling , Enzymes , Lignocellulose -- Biodegradation , Escherichia coli , Oligosaccharides , Hydroxycinnamic acids
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178224 , vital:42922 , 10.21504/10962/178224
- Description: Agricultural residues are readily available and inexpensive renewable resources that can be used as raw materials for the production of value-added chemicals. The application of enzymes to facilitate the degradation of agricultural residues has long been considered the most environmentally friendly strategy for converting this material into good quality value-added chemicals. However, agricultural residues are typically lignocellulosic in composition and recalcitrant to enzymatic hydrolysis. Due to this recalcitrant nature, the complete degradation of biomass residues requires the synergistic action of a broad range of enzymes. The development and optimisation of synergistic enzyme cocktails is an effective approach for achieving high hydrolysis efficiency of lignocellulosic biomass. The aim of the current study was to evaluate the synergistic interactions between two termite metagenome-derived feruloyl esterases (FAE6 and FAE5) and endo-xylanases for the production of hydroxycinnamic acids and xylo-oligosaccharides (XOS) from model substrates, and untreated and pre-treated agricultural residues. Firstly, the two fae genes were heterologously expressed in Escherichia coli, and the recombinant enzymes were purified to homogeneity. The biochemical properties of the purified recombinant FAEs and xylanases (XT6 and Xyn11) were then assessed to determine the factors which influenced their activities and to select suitable operating conditions for synergy studies. An optimal protein loading ratio of xylanases to FAEs required to maximise the release of both reducing sugar and ferulic acid (FA) was established using 0.5% (w/v) insoluble wheat arabinoxylan (a model substrate). The enzyme combination of 66% xylanase and 33% FAE (on a protein loading basis) produced the highest amounts of reducing sugars and FA. The enzyme combination of XT6 (GH10 xylanase) and FAE5 or FAE6 liberated the highest amount of FA while a combination of Xyn11 (GH11 xylanase) and FAE5 or FAE6 produced the highest reducing sugar content. The synergistic interactions which were established between the xylanases and FAEs were further investigated using agricultural residues (corn cobs, rice straw and sugarcane bagasse). The three substrates were subjected to hydrothermal and dilute acid pre-treatment prior to synergy studies. It is generally known that, during pre-treatment, many compounds can be produced which may influence enzymatic hydrolysis. The effects of these by-products were assessed and it was found that lignin and its degradation products were the most inhibitory to the FAEs. The optimised enzyme cocktail was then applied to 1% (w/v) of untreated and pre-treated substrates for the efficient production of XOS and hydroxycinnamic acids. A significant improvement in xylanase substrate degradation was observed, especially with the combination of 66% Xyn11 and 33% FAE6 which displayed an improvement in reducing sugars of approximately 1.9-fold and 3.4-fold for hydrothermal and acid pre-treated corn cobs (compared to when Xyn11 was used alone), respectively. The study demonstrated that pre-treatment substantially enhanced the enzymatic hydrolysis of corn cobs and rice straw. Analysis of the hydrolysate product profiles revealed that the optimised enzyme cocktail displayed great potential for releasing XOS with a low degree of polymerisation. In conclusion, this study provided significant insights into the mechanism of synergistic interactions between xylanases and metagenome-derived FAEs during the hydrolysis of various substrates. The study also demonstrated that optimised enzyme cocktails combined with low severity pre-treatment can facilitate the potential use of xylan-rich lignocellulosic biomass for the production of valuable products in the future. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Mkabayi, Lithalethu
- Date: 2021-04
- Subjects: Esterases , Xylanases , Hydrolysis , Agricultural wastes -- Recycling , Enzymes , Lignocellulose -- Biodegradation , Escherichia coli , Oligosaccharides , Hydroxycinnamic acids
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178224 , vital:42922 , 10.21504/10962/178224
- Description: Agricultural residues are readily available and inexpensive renewable resources that can be used as raw materials for the production of value-added chemicals. The application of enzymes to facilitate the degradation of agricultural residues has long been considered the most environmentally friendly strategy for converting this material into good quality value-added chemicals. However, agricultural residues are typically lignocellulosic in composition and recalcitrant to enzymatic hydrolysis. Due to this recalcitrant nature, the complete degradation of biomass residues requires the synergistic action of a broad range of enzymes. The development and optimisation of synergistic enzyme cocktails is an effective approach for achieving high hydrolysis efficiency of lignocellulosic biomass. The aim of the current study was to evaluate the synergistic interactions between two termite metagenome-derived feruloyl esterases (FAE6 and FAE5) and endo-xylanases for the production of hydroxycinnamic acids and xylo-oligosaccharides (XOS) from model substrates, and untreated and pre-treated agricultural residues. Firstly, the two fae genes were heterologously expressed in Escherichia coli, and the recombinant enzymes were purified to homogeneity. The biochemical properties of the purified recombinant FAEs and xylanases (XT6 and Xyn11) were then assessed to determine the factors which influenced their activities and to select suitable operating conditions for synergy studies. An optimal protein loading ratio of xylanases to FAEs required to maximise the release of both reducing sugar and ferulic acid (FA) was established using 0.5% (w/v) insoluble wheat arabinoxylan (a model substrate). The enzyme combination of 66% xylanase and 33% FAE (on a protein loading basis) produced the highest amounts of reducing sugars and FA. The enzyme combination of XT6 (GH10 xylanase) and FAE5 or FAE6 liberated the highest amount of FA while a combination of Xyn11 (GH11 xylanase) and FAE5 or FAE6 produced the highest reducing sugar content. The synergistic interactions which were established between the xylanases and FAEs were further investigated using agricultural residues (corn cobs, rice straw and sugarcane bagasse). The three substrates were subjected to hydrothermal and dilute acid pre-treatment prior to synergy studies. It is generally known that, during pre-treatment, many compounds can be produced which may influence enzymatic hydrolysis. The effects of these by-products were assessed and it was found that lignin and its degradation products were the most inhibitory to the FAEs. The optimised enzyme cocktail was then applied to 1% (w/v) of untreated and pre-treated substrates for the efficient production of XOS and hydroxycinnamic acids. A significant improvement in xylanase substrate degradation was observed, especially with the combination of 66% Xyn11 and 33% FAE6 which displayed an improvement in reducing sugars of approximately 1.9-fold and 3.4-fold for hydrothermal and acid pre-treated corn cobs (compared to when Xyn11 was used alone), respectively. The study demonstrated that pre-treatment substantially enhanced the enzymatic hydrolysis of corn cobs and rice straw. Analysis of the hydrolysate product profiles revealed that the optimised enzyme cocktail displayed great potential for releasing XOS with a low degree of polymerisation. In conclusion, this study provided significant insights into the mechanism of synergistic interactions between xylanases and metagenome-derived FAEs during the hydrolysis of various substrates. The study also demonstrated that optimised enzyme cocktails combined with low severity pre-treatment can facilitate the potential use of xylan-rich lignocellulosic biomass for the production of valuable products in the future. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
A mineralogical study of phosphate mineralisation in the Nkombwa Hill Carbonatite
- Authors: Mapholi, Thendo
- Date: 2021-10-29
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/294797 , vital:57256
- Description: Thesis embargoed. Release date October 2023. , Thesis (MSc) -- Faculty of Science, Geology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Mapholi, Thendo
- Date: 2021-10-29
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/294797 , vital:57256
- Description: Thesis embargoed. Release date October 2023. , Thesis (MSc) -- Faculty of Science, Geology, 2021
- Full Text:
- Date Issued: 2021-10-29
The Integration of Personally-owned Information and Communication Technologies (PICTs) for Teaching and Learning in Resource-Constrained Higher Education Environments – The Case of a Nigerian University
- Authors: Lewis, Oláñrewájú Olúrotimi
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163582 , vital:41050 , doi:10.21504/10962/163582
- Description: Thesis (PhD)--Rhodes University, Faculty of Commerce, Information Systems, 2020
- Full Text:
- Date Issued: 2020
- Authors: Lewis, Oláñrewájú Olúrotimi
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163582 , vital:41050 , doi:10.21504/10962/163582
- Description: Thesis (PhD)--Rhodes University, Faculty of Commerce, Information Systems, 2020
- Full Text:
- Date Issued: 2020
An analysis of intrasemiotic and intersemiotic relations of textual and visual modes in Namibian school science textbooks
- Authors: Mateus, Venasius
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia , Semiotics , Force and energy , Visual learning , Verbal learning , Functionalism (Linguistics) , Science -- Textbooks
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177203 , vital:42799
- Description: Although science education in Namibia receives much attention, learners’ performance is low in subjects such as Physical Sciences. The topic of Forces is among the topics in Physical Sciences where learners perform poorly. The provision of basic education in Namibia faces many challenges. One of these is that many teachers are not fully qualified for teaching the subjects they currently teach. Another (possibly related) challenge is that the majority of teachers in Namibian schools rely heavily on school textbooks when planning their lessons. In addition, learners use school textbooks as learning aids. The textbooks are developed and published in the private sector and based on the national curriculum statements. Quality of education has been amongst the major goals of education in Namibia. For quality assurance purposes, school science textbooks have to undergo a formal evaluation process. School textbooks, especially science textbooks, are multimodal. This means that they are designed with various modes, such as the textual and visual, often used in expressing scientific meanings. Literature reveals the textual and visual as individual modes having their own affordances, however, when integrated in school science textbooks contribute to strengthened meanings. No study published was found in Namibia or elsewhere that focused on analysing the intrasemiotic and intersemiotic sense relations of the textual and visual modes in Namibian school Physical Sciences textbooks. This study therefore aimed at contributing to filling this knowledge gap. The research is a qualitative case study and employed the interpretive paradigm. The selected Physical Sciences textbooks that constitute the data in this study were explored in depth via document analysis. Related textual and visual modes in the Physical Sciences textbooks were analysed in order to help answer the research questions of the study. Systemic Functional Linguistics was employed as the theoretical underpinning for this study. In this study, the sense relations were explored in terms of the sense relation themes which were coded and developed from common features of scientific discourse. The results reveal that scientific knowledge within the textual mode in the topic of Forces is communicated mostly through synonymy and repetition while within the visual mode it is mostly through antonymy, collocation, and synonymy. This contributed to meaning potential in the topic of Forces for the three Physical Sciences textbooks. The results further indicated that the overall cohesion within the textual and visual modes in the topic of Forces is achieved since repetition, which is the most direct form of lexical cohesion together with synonymy, collocation, and antonymy which are aspects of cohesion, occurred most frequently within these modes. This result further indicates that meaning potential in the topic of Forces in the three Physical Sciences textbooks were strengthened. While some sense relations occurred most frequently within individual modes, they were less frequent in other modes and vice versa. This indicates that different modes have different affordances. Finally, it was found that combining the textual and visual modes in the topic of Forces contributes to intersemiotic complementarity being achieved through the sense relations of collocation, hyponymy, and meronymy. , Thesis (MEd) -- Education, Education, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Mateus, Venasius
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia , Semiotics , Force and energy , Visual learning , Verbal learning , Functionalism (Linguistics) , Science -- Textbooks
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177203 , vital:42799
- Description: Although science education in Namibia receives much attention, learners’ performance is low in subjects such as Physical Sciences. The topic of Forces is among the topics in Physical Sciences where learners perform poorly. The provision of basic education in Namibia faces many challenges. One of these is that many teachers are not fully qualified for teaching the subjects they currently teach. Another (possibly related) challenge is that the majority of teachers in Namibian schools rely heavily on school textbooks when planning their lessons. In addition, learners use school textbooks as learning aids. The textbooks are developed and published in the private sector and based on the national curriculum statements. Quality of education has been amongst the major goals of education in Namibia. For quality assurance purposes, school science textbooks have to undergo a formal evaluation process. School textbooks, especially science textbooks, are multimodal. This means that they are designed with various modes, such as the textual and visual, often used in expressing scientific meanings. Literature reveals the textual and visual as individual modes having their own affordances, however, when integrated in school science textbooks contribute to strengthened meanings. No study published was found in Namibia or elsewhere that focused on analysing the intrasemiotic and intersemiotic sense relations of the textual and visual modes in Namibian school Physical Sciences textbooks. This study therefore aimed at contributing to filling this knowledge gap. The research is a qualitative case study and employed the interpretive paradigm. The selected Physical Sciences textbooks that constitute the data in this study were explored in depth via document analysis. Related textual and visual modes in the Physical Sciences textbooks were analysed in order to help answer the research questions of the study. Systemic Functional Linguistics was employed as the theoretical underpinning for this study. In this study, the sense relations were explored in terms of the sense relation themes which were coded and developed from common features of scientific discourse. The results reveal that scientific knowledge within the textual mode in the topic of Forces is communicated mostly through synonymy and repetition while within the visual mode it is mostly through antonymy, collocation, and synonymy. This contributed to meaning potential in the topic of Forces for the three Physical Sciences textbooks. The results further indicated that the overall cohesion within the textual and visual modes in the topic of Forces is achieved since repetition, which is the most direct form of lexical cohesion together with synonymy, collocation, and antonymy which are aspects of cohesion, occurred most frequently within these modes. This result further indicates that meaning potential in the topic of Forces in the three Physical Sciences textbooks were strengthened. While some sense relations occurred most frequently within individual modes, they were less frequent in other modes and vice versa. This indicates that different modes have different affordances. Finally, it was found that combining the textual and visual modes in the topic of Forces contributes to intersemiotic complementarity being achieved through the sense relations of collocation, hyponymy, and meronymy. , Thesis (MEd) -- Education, Education, 2021
- Full Text:
- Date Issued: 2021-04
In silico identification of selective novel hits against the active site of wild type mycobacterium tuberculosis pyrazinamidase and its mutants
- Authors: Gowo, Prudence
- Date: 2021-04
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Multidrug resistance , Antitubercular agents , Molecular dynamics , Hydrogen bonding , Ligand binding (Biochemistry) , Dynamic Residue Network
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178007 , vital:42898
- Description: The World Health Organization declared Tuberculosis a global health emergency and has set a goal to eradicate it by 2035. However, effective treatment and control of the disease is being hindered by the emerging Multi-Drug Resistant and Extensively Drug Resistant strains on the most effective first line prodrug, Pyrazinamide (PZA). Studies have shown that the main cause of PZA resistance is due to mutations in the pncA gene that codes for the target protein Pyrazinamidase (PZase). Therefore, this study aimed to identify novel drug compounds that bind to the active site of wild type PZase and study the dynamics of these potential anti-TB drugs in the mutant systems of PZase. This approach will aid in identifying drugs that may be repurposed for TB therapy and/or designed to counteract PZA resistance. This was achieved by screening 2089 DrugBank compounds against the whole wild type (WT) PZase protein in molecular docking using AutoDOCK4.2. Compound screening based on docking binding energy, hydrogen bonds, molecular weight and active site proximity identified 47 compounds meeting all the set selection criteria. The stability of these compounds were analysed in Molecular Dynamic (MD) simulations and were further studied in PZase mutant systems of A3P, A134V, A146V, D8G, D49A, D49G, D63G, H51P, H137R, L85R, L116R, Q10P, R140S, T61P, V139M and Y103S. Generally, mutant-ligand systems displayed little deviation from the WT systems. The compound systems remained compact, with less fluctuations and more hydrogen bond interactions throughout the simulation (DB00255, DB00655, DB00672, DB00782, DB00977, DB01196, DB04573, DB06414, DB08981, DB11181, DB11760, DB13867, DB13952). From this research study, potential drugs that may be repurposed for TB therapy were identified. Majority of these drugs are currently used in the treatment of hypertension, menopause disorders and inflammation. To further understand the mutant-ligand dynamic systems, calculations such as Dynamic Residue Network (DRN) may be done. Also, the bioactivity of these drugs on Mycobacterium tuberculosis may be studied in wet laboratory, to understand their clinical impart in vivo experiments. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Gowo, Prudence
- Date: 2021-04
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Multidrug resistance , Antitubercular agents , Molecular dynamics , Hydrogen bonding , Ligand binding (Biochemistry) , Dynamic Residue Network
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178007 , vital:42898
- Description: The World Health Organization declared Tuberculosis a global health emergency and has set a goal to eradicate it by 2035. However, effective treatment and control of the disease is being hindered by the emerging Multi-Drug Resistant and Extensively Drug Resistant strains on the most effective first line prodrug, Pyrazinamide (PZA). Studies have shown that the main cause of PZA resistance is due to mutations in the pncA gene that codes for the target protein Pyrazinamidase (PZase). Therefore, this study aimed to identify novel drug compounds that bind to the active site of wild type PZase and study the dynamics of these potential anti-TB drugs in the mutant systems of PZase. This approach will aid in identifying drugs that may be repurposed for TB therapy and/or designed to counteract PZA resistance. This was achieved by screening 2089 DrugBank compounds against the whole wild type (WT) PZase protein in molecular docking using AutoDOCK4.2. Compound screening based on docking binding energy, hydrogen bonds, molecular weight and active site proximity identified 47 compounds meeting all the set selection criteria. The stability of these compounds were analysed in Molecular Dynamic (MD) simulations and were further studied in PZase mutant systems of A3P, A134V, A146V, D8G, D49A, D49G, D63G, H51P, H137R, L85R, L116R, Q10P, R140S, T61P, V139M and Y103S. Generally, mutant-ligand systems displayed little deviation from the WT systems. The compound systems remained compact, with less fluctuations and more hydrogen bond interactions throughout the simulation (DB00255, DB00655, DB00672, DB00782, DB00977, DB01196, DB04573, DB06414, DB08981, DB11181, DB11760, DB13867, DB13952). From this research study, potential drugs that may be repurposed for TB therapy were identified. Majority of these drugs are currently used in the treatment of hypertension, menopause disorders and inflammation. To further understand the mutant-ligand dynamic systems, calculations such as Dynamic Residue Network (DRN) may be done. Also, the bioactivity of these drugs on Mycobacterium tuberculosis may be studied in wet laboratory, to understand their clinical impart in vivo experiments. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
A social realist study of employability development in engineering education
- Authors: Nudelman, Gabrielle Reeve
- Date: 2018
- Subjects: Critical realism , Electrical engineering -- Study and teaching (Higher) -- South Africa -- Cape Town , Employability , Career education -- South Africa -- Cape Town , School-to-work transition -- South Africa -- Cape Town
- Language: English
- Type: thesis , text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62884 , vital:28307
- Description: This qualitative case study of a course pairing offered to final-year electrical engineering students at the University of Cape Town in 2015 was undertaken in order to better understand the ways in which participation in undergraduate courses can prepare engineering students for the workplace. The course pairing consisted of New Venture Planning and Professional Communication Studies. While the former aimed to expose students to the knowledge relating to starting a new business, the latter focused on teaching students how to create written and oral texts to support such an endeavour. Using Roy Bhaskar’s critical realism as a theoretical underlabourer, the study develops understandings regarding the generative mechanisms at work during the two courses. In support of this, the study posits an understanding of employability that moves beyond the acquisition of discrete workplace skills. Rather, employability is conceptualised as discursive transformation, with students being deemed “work-ready” when they develop discursive identities as engineers. Data generation took place by means of focus group and individual interviews, ethnographic observation and documentary research. Margaret Archer’s social realist tools – in particular, analytical dualism and the morphogenetic framework were used to trace the students’ transformations over the course pairing. It was argued that those students who developed discursive identities of engineers were those who, in Archer’s terms, emerged as social actors at the end of the course pairing. Two characteristics of the courses were found to enable this transformation: those parts that promoted deepened understanding of what the role of “engineer” entailed and the parts that provided spaces for students to develop their own personal identities. The findings of the study indicated that discursive identities as engineers were more likely to be developed through the group work and spaces for reflection engendered by the courses than as a result of the formal curriculum. The implications of the research are that, while a focus on employability in engineering education is valid and productive, this needs to be supported by opportunities for authentic learning experiences which afford students the opportunity to engage in learning that promotes real-life application of knowledge. , Thesis (PhD)--Rhodes University, Faculty of Education, Education, 2018
- Full Text:
- Date Issued: 2018
- Authors: Nudelman, Gabrielle Reeve
- Date: 2018
- Subjects: Critical realism , Electrical engineering -- Study and teaching (Higher) -- South Africa -- Cape Town , Employability , Career education -- South Africa -- Cape Town , School-to-work transition -- South Africa -- Cape Town
- Language: English
- Type: thesis , text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62884 , vital:28307
- Description: This qualitative case study of a course pairing offered to final-year electrical engineering students at the University of Cape Town in 2015 was undertaken in order to better understand the ways in which participation in undergraduate courses can prepare engineering students for the workplace. The course pairing consisted of New Venture Planning and Professional Communication Studies. While the former aimed to expose students to the knowledge relating to starting a new business, the latter focused on teaching students how to create written and oral texts to support such an endeavour. Using Roy Bhaskar’s critical realism as a theoretical underlabourer, the study develops understandings regarding the generative mechanisms at work during the two courses. In support of this, the study posits an understanding of employability that moves beyond the acquisition of discrete workplace skills. Rather, employability is conceptualised as discursive transformation, with students being deemed “work-ready” when they develop discursive identities as engineers. Data generation took place by means of focus group and individual interviews, ethnographic observation and documentary research. Margaret Archer’s social realist tools – in particular, analytical dualism and the morphogenetic framework were used to trace the students’ transformations over the course pairing. It was argued that those students who developed discursive identities of engineers were those who, in Archer’s terms, emerged as social actors at the end of the course pairing. Two characteristics of the courses were found to enable this transformation: those parts that promoted deepened understanding of what the role of “engineer” entailed and the parts that provided spaces for students to develop their own personal identities. The findings of the study indicated that discursive identities as engineers were more likely to be developed through the group work and spaces for reflection engendered by the courses than as a result of the formal curriculum. The implications of the research are that, while a focus on employability in engineering education is valid and productive, this needs to be supported by opportunities for authentic learning experiences which afford students the opportunity to engage in learning that promotes real-life application of knowledge. , Thesis (PhD)--Rhodes University, Faculty of Education, Education, 2018
- Full Text:
- Date Issued: 2018