Exploring affordances and hindrances when indigenous knowledge is integrated in the topic on waves and sound in a Grade 10 Physical Sciences township class
- Authors: Manyana, Xolani Justice
- Date: 2020
- Subjects: Physical sciences -- Study and teaching (Secondary) -- South Africa , Physical sciences -- Study and teaching (Secondary) -- South Africa -- Case studies , Ethnoscience -- Study and teaching -- South Africa , Schools -- South Africa -- Curricula , Social change
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142889 , vital:38173
- Description: The lack of interest and hence the decline in the number of learners doing Science in schools, is attributed in part to the decontextualised ways in which Science is taught. As an attempt to address this challenge, the new South African National Curriculum Policy Statement (CAPS) encourages Science teachers to use culturally responsive pedagogies through integrating local or indigenous knowledge (IK) in Science lessons to make it accessible and relevant to learners. But, it does not explicitly state how Science teachers should go about enacting this. It is against this caveat that this study aimed at finding out indigenous practices and knowledge in the community and from two community members that could be integrated into the topic on waves and sound in Grade 10 Physical Sciences lessons with the view to establishing its influence (or not) on learners’ conceptions and dispositions towards Science. The study was conducted at Buyelembo Combined School (pseudonym), a township school in the Sarah Baartman District, in the Eastern Cape in South Africa. The research participants were 18 Grade 10 Physical Sciences learners, two Physical Sciences teachers and two community members. Data were generated using the learners’ group activity, discussions and presentations, observations (participatory observations and lesson observations), stimulated recall interviews and reflections. A thematic and inductive-deductive approach to data analysis was employed to come up with sub-themes and themes. Underpinned by an interpretivist perspective and informed by Vygotsky’s socio-cultural theory, a qualitative case study approach was adopted. Additionally, Ogunniyi’s Contiguity Argumentative Theory (CAT) was used as an analytical framework. The five cognitive states of CAT were employed to analyse data during the social interactions to surface any contradictions. The findings from this study revealed that there are indigenous practices and knowledge in relation to the sea that can be integrated into the topic on waves and sound in Grade 10 Physical Sciences lessons. However, regarding relevance of those indigenous practices and knowledge to science, the study revealed that the learners found no relevance at all but discussions and argumentation were enhanced. In addition, findings from this study revealed that the learners’ conceptions, dispositions, and sense-making in science were influenced positively through using hands-on practical activities when teaching Science concepts. Lastly, the study revealed that the use of mother tongue by the community members, learners and the teachers together with the language of learning and teaching promoted learner talk. Based on the findings of this study, I recommend that there is a need to support teachers on how to integrate indigenous practices and knowledge in their teaching, particularly when teaching Physical Sciences.
- Full Text:
- Date Issued: 2020
- Authors: Manyana, Xolani Justice
- Date: 2020
- Subjects: Physical sciences -- Study and teaching (Secondary) -- South Africa , Physical sciences -- Study and teaching (Secondary) -- South Africa -- Case studies , Ethnoscience -- Study and teaching -- South Africa , Schools -- South Africa -- Curricula , Social change
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142889 , vital:38173
- Description: The lack of interest and hence the decline in the number of learners doing Science in schools, is attributed in part to the decontextualised ways in which Science is taught. As an attempt to address this challenge, the new South African National Curriculum Policy Statement (CAPS) encourages Science teachers to use culturally responsive pedagogies through integrating local or indigenous knowledge (IK) in Science lessons to make it accessible and relevant to learners. But, it does not explicitly state how Science teachers should go about enacting this. It is against this caveat that this study aimed at finding out indigenous practices and knowledge in the community and from two community members that could be integrated into the topic on waves and sound in Grade 10 Physical Sciences lessons with the view to establishing its influence (or not) on learners’ conceptions and dispositions towards Science. The study was conducted at Buyelembo Combined School (pseudonym), a township school in the Sarah Baartman District, in the Eastern Cape in South Africa. The research participants were 18 Grade 10 Physical Sciences learners, two Physical Sciences teachers and two community members. Data were generated using the learners’ group activity, discussions and presentations, observations (participatory observations and lesson observations), stimulated recall interviews and reflections. A thematic and inductive-deductive approach to data analysis was employed to come up with sub-themes and themes. Underpinned by an interpretivist perspective and informed by Vygotsky’s socio-cultural theory, a qualitative case study approach was adopted. Additionally, Ogunniyi’s Contiguity Argumentative Theory (CAT) was used as an analytical framework. The five cognitive states of CAT were employed to analyse data during the social interactions to surface any contradictions. The findings from this study revealed that there are indigenous practices and knowledge in relation to the sea that can be integrated into the topic on waves and sound in Grade 10 Physical Sciences lessons. However, regarding relevance of those indigenous practices and knowledge to science, the study revealed that the learners found no relevance at all but discussions and argumentation were enhanced. In addition, findings from this study revealed that the learners’ conceptions, dispositions, and sense-making in science were influenced positively through using hands-on practical activities when teaching Science concepts. Lastly, the study revealed that the use of mother tongue by the community members, learners and the teachers together with the language of learning and teaching promoted learner talk. Based on the findings of this study, I recommend that there is a need to support teachers on how to integrate indigenous practices and knowledge in their teaching, particularly when teaching Physical Sciences.
- Full Text:
- Date Issued: 2020
Exploring career information through developmental contextual focus groups with youth from disadvantaged backgrounds
- Authors: Phala, Phorogohlo Modipadi
- Date: 2020
- Subjects: Vocational guidance , Educational counseling , Focus groups , Action research , Youth -- South Africa -- Social conditions -- 1994- , Parental influences – South Africa , Vocational guidance -- Parent participation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/130594 , vital:36442
- Description: This study investigates the importance of initiating career exploration discussions with young people from disadvantaged backgrounds, using the developmental-contextual framework of career development by Vondracek, Lerner & Schulenburg (1986). This model stresses the dynamic relationship between an individual, the ever-changing environment and how each influences the other. Based upon an earlier study by Spencer (1999), this study aims to explore the developmental-contextual model as the basis of successive group discussions at a pivotal moment in the lives of the youth from disadvantaged backgrounds. In addition, it aims to understand individuals’ perceptions of career education and the influences on career decision-making and aspiration. Data were collected through setting up and running a focus group session once a week over a period of five weeks, in which different career-related topics were discussed. The sample consisted of nine unemployed students who were currently not in a tertiary institution between the ages of 18-25 years. The findings indicated a noteworthy need for more relevant career interventions to be investigated and implemented for the diverse South African population. The study’s findings demonstrated that individuals might be more open to exploring career development through group rather than individual counselling. It was found that parents are the main career influencers in their children’s lives. Mothers were experienced as role models, supporters and encouragers while fathers were experienced as absent and unsupportive, playing little or no role in their children’s lives. The participants found this form of career exploration appealing as it allowed for peer consultation and the freedom to discuss career issues in a non-judgemental setting.
- Full Text:
- Date Issued: 2020
- Authors: Phala, Phorogohlo Modipadi
- Date: 2020
- Subjects: Vocational guidance , Educational counseling , Focus groups , Action research , Youth -- South Africa -- Social conditions -- 1994- , Parental influences – South Africa , Vocational guidance -- Parent participation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/130594 , vital:36442
- Description: This study investigates the importance of initiating career exploration discussions with young people from disadvantaged backgrounds, using the developmental-contextual framework of career development by Vondracek, Lerner & Schulenburg (1986). This model stresses the dynamic relationship between an individual, the ever-changing environment and how each influences the other. Based upon an earlier study by Spencer (1999), this study aims to explore the developmental-contextual model as the basis of successive group discussions at a pivotal moment in the lives of the youth from disadvantaged backgrounds. In addition, it aims to understand individuals’ perceptions of career education and the influences on career decision-making and aspiration. Data were collected through setting up and running a focus group session once a week over a period of five weeks, in which different career-related topics were discussed. The sample consisted of nine unemployed students who were currently not in a tertiary institution between the ages of 18-25 years. The findings indicated a noteworthy need for more relevant career interventions to be investigated and implemented for the diverse South African population. The study’s findings demonstrated that individuals might be more open to exploring career development through group rather than individual counselling. It was found that parents are the main career influencers in their children’s lives. Mothers were experienced as role models, supporters and encouragers while fathers were experienced as absent and unsupportive, playing little or no role in their children’s lives. The participants found this form of career exploration appealing as it allowed for peer consultation and the freedom to discuss career issues in a non-judgemental setting.
- Full Text:
- Date Issued: 2020
Exploring socialities on Black Twitter: an ethnographic study of everyday concerns of South African users in 2018 and 2019
- Authors: Adebayo, Binwe
- Date: 2020
- Subjects: Twitter (Firm) , Social media South Africa , Social media and society South Africa , Black people and mass media South Africa , Language and the Internet South Africa , Mass media and culture South Africa , Race in mass media , Ethnicity in mass media , Mass media and minorities South Africa , Mass media Social aspects South Africa , Sex differences in mass media , Social media Political aspects South Africa , South Africa Social conditions , Finance In mass media , Intersectionality (Sociology) South Africa , Black Twitter
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140575 , vital:37900
- Description: In this thesis, I examine the phenomenon of Black Twitter, as it exists in South Africa. Drawing on its socio-cultural and linguistic elements, I analyse the kinds of socialities which are constituted on the platform. In the study, I do this by focusing on the key issues which drive the space by evaluating the key everyday concerns as expressed by its users. As such, the overarching lens focuses on three elements: Firstly, the idea of socialities and the way in which they manifest in online spaces; a focus on the everyday as an important site for social inquiry; and lastly the issue of ‘blackness’, in terms of the way it is used and understood in the South African Black Twitter context. Historically, the Black Twitter space has been linked almost exclusively to its broad base of African American users, who are significant both in terms of their numbers, and their impact on online social culture. However, in this study I engage with the ways in which Black Twitter has been adopted, co-opted and used by young South Africans. As a bona fide ‘member’ of South African Black Twitter, my approach to the study was cyberethnographic. Drawing on my access to the space, my knowledge of many of its members and dynamics, I engaged in participant observation as my primary methodology. My discussion focuses on three areas of everyday concerns, namely: gender and sexuality; race and politics; finances and the economy. These three areas emerge both as prominent sites of discussion, but also give the best insight into the ways in which young South Africans are grappling with these issues. My analysis focuses on how everyday concerns are handled on the platform, and I focus on the deployment of solidarity, formal language, platform-based language and the invocation of blackness. I argue in my conclusion that while the structure of the broad Black Twitter space reflects a leaning towards a digital public sphere, that the process and construction of Black Twitter’s ideas and content are approached via an incomplete, fluid convivial approach.
- Full Text:
- Date Issued: 2020
- Authors: Adebayo, Binwe
- Date: 2020
- Subjects: Twitter (Firm) , Social media South Africa , Social media and society South Africa , Black people and mass media South Africa , Language and the Internet South Africa , Mass media and culture South Africa , Race in mass media , Ethnicity in mass media , Mass media and minorities South Africa , Mass media Social aspects South Africa , Sex differences in mass media , Social media Political aspects South Africa , South Africa Social conditions , Finance In mass media , Intersectionality (Sociology) South Africa , Black Twitter
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140575 , vital:37900
- Description: In this thesis, I examine the phenomenon of Black Twitter, as it exists in South Africa. Drawing on its socio-cultural and linguistic elements, I analyse the kinds of socialities which are constituted on the platform. In the study, I do this by focusing on the key issues which drive the space by evaluating the key everyday concerns as expressed by its users. As such, the overarching lens focuses on three elements: Firstly, the idea of socialities and the way in which they manifest in online spaces; a focus on the everyday as an important site for social inquiry; and lastly the issue of ‘blackness’, in terms of the way it is used and understood in the South African Black Twitter context. Historically, the Black Twitter space has been linked almost exclusively to its broad base of African American users, who are significant both in terms of their numbers, and their impact on online social culture. However, in this study I engage with the ways in which Black Twitter has been adopted, co-opted and used by young South Africans. As a bona fide ‘member’ of South African Black Twitter, my approach to the study was cyberethnographic. Drawing on my access to the space, my knowledge of many of its members and dynamics, I engaged in participant observation as my primary methodology. My discussion focuses on three areas of everyday concerns, namely: gender and sexuality; race and politics; finances and the economy. These three areas emerge both as prominent sites of discussion, but also give the best insight into the ways in which young South Africans are grappling with these issues. My analysis focuses on how everyday concerns are handled on the platform, and I focus on the deployment of solidarity, formal language, platform-based language and the invocation of blackness. I argue in my conclusion that while the structure of the broad Black Twitter space reflects a leaning towards a digital public sphere, that the process and construction of Black Twitter’s ideas and content are approached via an incomplete, fluid convivial approach.
- Full Text:
- Date Issued: 2020
Exploring the influence of marine science camps on learners’ motivation and dispositions towards scientific inquiry
- Authors: Hambaze, Nozipiwo
- Date: 2020
- Subjects: Science projects , Marine sciences -- Study and teaching -- South Africa -- Case studies , Active learning , Science camps -- South Africa -- Case studies , Experiential learning , Science -- Study and teaching -- South Africa -- Case studies , Motivation in education -- South Africa -- Case studies
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/163626 , vital:41062
- Description: For a number of years, it has been observed that learners’ motivation towards science has decreased , especially when th ey get to higher grades in secondary school. Strengthening learners’ motivation has become a very important area for educators to understand and reflect on. Many studies suggest that inquiry - based learning activities can provide a conducive learning enviro nment and build up learners ’ abilities and motivation to learn science beyond the classroom. It is against this backdrop that t his interventionist study s ought to investigate the influence of marine science camps on learners’ motivation towards scientific inquiry. The study was informed by Vygotsky ’s social constructivist theory and Wenger ’s community of practice theory. The participants were 21 grade 10 science learners from seven high schools in the Eastern Cape in South Africa. In order to answer the research questions , data w ere collected through the use of Student Motivation T owards Science Learning (SMTSL) questionnaires prior and post science camp, learner reflection journals and focus group interviews. Excel was used to analyse quantitative data w hereas an inductive - deductive thematic approach was used to analyse the qualitative data.The findin gs of the study revealed that through active participation learners’ dispositions shifted and became more positive after the scientific inquiry activity experience at the marine science camp. Furthermore , the findings of the study revealed that as a result of the marine science camp experiences learners were highly motivated to develop their own marine related science projects for the science fairs. Science fairs bear the testimony as one learner did not only co nduct a marine related project for a science fair but was awarded a gold medal at a regional science fair and a silver medal the national fair. The same lea r ne r was awarded an opportunity to present his project in other international fair. Notably also, l earners displayed increase science motivation as a result of participating at the marine science camp. iv This study thus recommends that i n order to enhance scie ntific inquiry among science learners, efforts in developing out - of - school programs not only by th e department of education but also other stakeholders such as universities are needed to inspire and motivate more learners in sciences. Additionally , pure sc ience faculties and social science s should work closely with each other to promote science.
- Full Text:
- Date Issued: 2020
- Authors: Hambaze, Nozipiwo
- Date: 2020
- Subjects: Science projects , Marine sciences -- Study and teaching -- South Africa -- Case studies , Active learning , Science camps -- South Africa -- Case studies , Experiential learning , Science -- Study and teaching -- South Africa -- Case studies , Motivation in education -- South Africa -- Case studies
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/163626 , vital:41062
- Description: For a number of years, it has been observed that learners’ motivation towards science has decreased , especially when th ey get to higher grades in secondary school. Strengthening learners’ motivation has become a very important area for educators to understand and reflect on. Many studies suggest that inquiry - based learning activities can provide a conducive learning enviro nment and build up learners ’ abilities and motivation to learn science beyond the classroom. It is against this backdrop that t his interventionist study s ought to investigate the influence of marine science camps on learners’ motivation towards scientific inquiry. The study was informed by Vygotsky ’s social constructivist theory and Wenger ’s community of practice theory. The participants were 21 grade 10 science learners from seven high schools in the Eastern Cape in South Africa. In order to answer the research questions , data w ere collected through the use of Student Motivation T owards Science Learning (SMTSL) questionnaires prior and post science camp, learner reflection journals and focus group interviews. Excel was used to analyse quantitative data w hereas an inductive - deductive thematic approach was used to analyse the qualitative data.The findin gs of the study revealed that through active participation learners’ dispositions shifted and became more positive after the scientific inquiry activity experience at the marine science camp. Furthermore , the findings of the study revealed that as a result of the marine science camp experiences learners were highly motivated to develop their own marine related science projects for the science fairs. Science fairs bear the testimony as one learner did not only co nduct a marine related project for a science fair but was awarded a gold medal at a regional science fair and a silver medal the national fair. The same lea r ne r was awarded an opportunity to present his project in other international fair. Notably also, l earners displayed increase science motivation as a result of participating at the marine science camp. iv This study thus recommends that i n order to enhance scie ntific inquiry among science learners, efforts in developing out - of - school programs not only by th e department of education but also other stakeholders such as universities are needed to inspire and motivate more learners in sciences. Additionally , pure sc ience faculties and social science s should work closely with each other to promote science.
- Full Text:
- Date Issued: 2020
Exploring working with Grade 6 Elementary Agricultural Science teachers on how to integrate local knowledge in food preservation
- Authors: Sabina, Hashondili
- Date: 2020
- Subjects: Agriculture -- Study and teaching (Elementary) -- Namibia , Food -- Preservation -- Study and teaching (Elementary) -- Namibia , Education, Elementary -- Namibia , Ethnoscience -- Study and teaching (Elementary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/148093 , vital:38709
- Description: Many scholars have reported that science teachers are grappling with linking science to learners’ everyday life experiences and Namibian science teachers are no exception. As a result, learners are finding that scientific concepts often remain decontextualised and abstract. In light of this, the Namibian National Curriculum indicates that teaching and learning should start with the knowledge and experiences of learners from home. It also encourages teachers to integrate local knowledge into their science lessons but does not give proper guidelines on how science teachers should go about enacting this. This tension between curriculum formulation and implementation triggered my interest to carry out an interventionist research study aimed at exploring working with Grade 6 Elementary Agricultural Science teachers on how to integrate local knowledge on food preservation in particular. This study is underpinned by an interpretive paradigm, within which a qualitative case study was employed. It was conducted with three Grade 6 Elementary Agricultural Science teachers from three different schools in the Oshana region of Namibia. I used semi-structured interviews, document analysis, workshop discussions, participatory observation and reflections to gather data. Vygotsky’s socio-cultural theory together with Shulman’s pedagogical content knowledge theories was used as lenses to analyse my data. The findings of the study revealed that the sample teachers understood what indigenous knowledge is and its benefits but struggled to integrate it in their lessons. The findings of the study further revealed that the presentations by the expert community members enabled these teachers to identify possible science topics that they could teach, using some of the traditional practices such as food preservation. The study thus recommends that teachers need to be supported on how to integrate local knowledge or indigenous knowledge in their classrooms. Teachers should therefore be involved in professional learning communities that will help them share their difficulties they encounter during their teaching practices and to collaboratively come up with strategies to overcome such difficulties. Community members who are custodians of the cultural heritage should be invited to share their indigenous knowledge with science teachers so that they can link it from community members to classroom science.
- Full Text:
- Date Issued: 2020
- Authors: Sabina, Hashondili
- Date: 2020
- Subjects: Agriculture -- Study and teaching (Elementary) -- Namibia , Food -- Preservation -- Study and teaching (Elementary) -- Namibia , Education, Elementary -- Namibia , Ethnoscience -- Study and teaching (Elementary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/148093 , vital:38709
- Description: Many scholars have reported that science teachers are grappling with linking science to learners’ everyday life experiences and Namibian science teachers are no exception. As a result, learners are finding that scientific concepts often remain decontextualised and abstract. In light of this, the Namibian National Curriculum indicates that teaching and learning should start with the knowledge and experiences of learners from home. It also encourages teachers to integrate local knowledge into their science lessons but does not give proper guidelines on how science teachers should go about enacting this. This tension between curriculum formulation and implementation triggered my interest to carry out an interventionist research study aimed at exploring working with Grade 6 Elementary Agricultural Science teachers on how to integrate local knowledge on food preservation in particular. This study is underpinned by an interpretive paradigm, within which a qualitative case study was employed. It was conducted with three Grade 6 Elementary Agricultural Science teachers from three different schools in the Oshana region of Namibia. I used semi-structured interviews, document analysis, workshop discussions, participatory observation and reflections to gather data. Vygotsky’s socio-cultural theory together with Shulman’s pedagogical content knowledge theories was used as lenses to analyse my data. The findings of the study revealed that the sample teachers understood what indigenous knowledge is and its benefits but struggled to integrate it in their lessons. The findings of the study further revealed that the presentations by the expert community members enabled these teachers to identify possible science topics that they could teach, using some of the traditional practices such as food preservation. The study thus recommends that teachers need to be supported on how to integrate local knowledge or indigenous knowledge in their classrooms. Teachers should therefore be involved in professional learning communities that will help them share their difficulties they encounter during their teaching practices and to collaboratively come up with strategies to overcome such difficulties. Community members who are custodians of the cultural heritage should be invited to share their indigenous knowledge with science teachers so that they can link it from community members to classroom science.
- Full Text:
- Date Issued: 2020
Falling towards the centre
- Authors: Maluleke, Vuyelwa
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142878 , vital:38125
- Description: I am interested in the poem as a textual body that is able to collect the ruptures, silences, music, and wounds of the body, Ukuzithutha, in order to perform their address. I seek to assemble these disfigured and fractured bodies, of which I am one, onto the page. And thus create an experimental, non-linear lyric of repetitions and fragmentations arranged into a memory text, to hold these stories against what Audre Lorde calls 'the tyranny of silence'. My thesis is influenced by Ntozake Shange's choreopoem, 'for colored girls who have considered suicide when the rainbow was enough', Claudia Rankine's 'Don't let me be Lonely', Sindiswa Bukusu's 'Loud and yellow laughter'. And Fiona Benson’s ‘Vertigo and Ghost’ whose form and lyric is a strong influence on the shape of the manuscript, and the construction of its mythologies.
- Full Text:
- Date Issued: 2020
- Authors: Maluleke, Vuyelwa
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142878 , vital:38125
- Description: I am interested in the poem as a textual body that is able to collect the ruptures, silences, music, and wounds of the body, Ukuzithutha, in order to perform their address. I seek to assemble these disfigured and fractured bodies, of which I am one, onto the page. And thus create an experimental, non-linear lyric of repetitions and fragmentations arranged into a memory text, to hold these stories against what Audre Lorde calls 'the tyranny of silence'. My thesis is influenced by Ntozake Shange's choreopoem, 'for colored girls who have considered suicide when the rainbow was enough', Claudia Rankine's 'Don't let me be Lonely', Sindiswa Bukusu's 'Loud and yellow laughter'. And Fiona Benson’s ‘Vertigo and Ghost’ whose form and lyric is a strong influence on the shape of the manuscript, and the construction of its mythologies.
- Full Text:
- Date Issued: 2020
Finite precision arithmetic in Polyphase Filterbank implementations
- Authors: Myburgh, Talon
- Date: 2020
- Subjects: Radio interferometers , Interferometry , Radio telescopes , Gate array circuits , Floating-point arithmetic , Python (Computer program language) , Polyphase Filterbank , Finite precision arithmetic , MeerKAT
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146187 , vital:38503
- Description: The MeerKAT is the most sensitive radio telescope in its class, and it is important that systematic effects do not limit the dynamic range of the instrument, preventing this sensitivity from being harnessed for deep integrations. During commissioning, spurious artefacts were noted in the MeerKAT passband and the root cause was attributed to systematic errors in the digital signal path. Finite precision arithmetic used by the Polyphase Filterbank (PFB) was one of the main factors contributing to the spurious responses, together with bugs in the firmware. This thesis describes a software PFB simulator that was built to mimic the MeerKAT PFB and allow investigation into the origin and mitigation of the effects seen on the telescope. This simulator was used to investigate the effects in signal integrity of various rounding techniques, overflow strategies and dual polarisation processing in the PFB. Using the simulator to investigate a number of different signal levels, bit-width and algorithmic scenarios, it gave insight into how the periodic dips occurring in the MeerKAT passband were the result of the implementation using an inappropriate rounding strategy. It further indicated how to select the best strategy for preventing overflow while maintaining high quantization effciency in the FFT. This practice of simulating the design behaviour in the PFB independently of the tools used to design the DSP firmware, is a step towards an end-to-end simulation of the MeerKAT system (or any radio telescope using nite precision digital signal processing systems). This would be useful for design, diagnostics, signal analysis and prototyping of the overall instrument.
- Full Text:
- Date Issued: 2020
- Authors: Myburgh, Talon
- Date: 2020
- Subjects: Radio interferometers , Interferometry , Radio telescopes , Gate array circuits , Floating-point arithmetic , Python (Computer program language) , Polyphase Filterbank , Finite precision arithmetic , MeerKAT
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146187 , vital:38503
- Description: The MeerKAT is the most sensitive radio telescope in its class, and it is important that systematic effects do not limit the dynamic range of the instrument, preventing this sensitivity from being harnessed for deep integrations. During commissioning, spurious artefacts were noted in the MeerKAT passband and the root cause was attributed to systematic errors in the digital signal path. Finite precision arithmetic used by the Polyphase Filterbank (PFB) was one of the main factors contributing to the spurious responses, together with bugs in the firmware. This thesis describes a software PFB simulator that was built to mimic the MeerKAT PFB and allow investigation into the origin and mitigation of the effects seen on the telescope. This simulator was used to investigate the effects in signal integrity of various rounding techniques, overflow strategies and dual polarisation processing in the PFB. Using the simulator to investigate a number of different signal levels, bit-width and algorithmic scenarios, it gave insight into how the periodic dips occurring in the MeerKAT passband were the result of the implementation using an inappropriate rounding strategy. It further indicated how to select the best strategy for preventing overflow while maintaining high quantization effciency in the FFT. This practice of simulating the design behaviour in the PFB independently of the tools used to design the DSP firmware, is a step towards an end-to-end simulation of the MeerKAT system (or any radio telescope using nite precision digital signal processing systems). This would be useful for design, diagnostics, signal analysis and prototyping of the overall instrument.
- Full Text:
- Date Issued: 2020
Flying Cows & Other Traumas
- Authors: Twijnstra, Philisiwe
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145513 , vital:38445
- Description: My thesis combines short stories and flash fiction and a short novella collection. Working between reality and fantasy. The collection both engage the strangeness of magic in everyday life and explore other worlds. The stories uses different points of view to highlight the impossibility of a single stable reality. The writing is heavily influenced by Amos Tutuola (The Palm-Wine Drunkard) for his big imagination and how he draws from Yoruba folklore and mixes myth to fiction. Mica Dean Hicks (Electricity and other dreams) he writes with simplicity and his settings always believable yet with one sentence everything becomes a different world of seen and unseen. Margarita Karapanou (Kassandra and the wolf) The tone of the book captured me, how she balances heavy social theme around a young girl, the tone changes from chapter to chapter - from surreal to hallucinatory to mythic to something in between all these modes. She writes rape, but not once has she mentioned rape, yet she is writing about rape. Some books that revolutionized the way I see stories are (Kintu) written by Jennifer Nansubuga Makumbi and (Homegoing) by Yaa Gyasi. They both draw from histories yet contemporize their stories. Which my thesis intends to do that in stories such ‘MoonEyed Maiden’ and Sorana. Flying Cows and Other Traumas is an exploration of female body, when the sacredness of the female body is dehumanized by social injustices. Each story is a stand alone; the structure holds the through-line of the collection which conditions the complexities, the rawness and bluntness of how imbalance our society is. When the body is tainted with unfairness and powered down- how does one come up from that? The collection deals with poverty, sexual assault, systemic injustice, and sexism and some stories draw from personal experiences and fears. The female body is used as a hostage of shame and commodity and the female protagonists in ‘Flying Cows & Other Traumas sharpen their own stuff and shields to face their own injustices through blurring lines of mundanity and fantastical with experimental tone.
- Full Text:
- Date Issued: 2020
- Authors: Twijnstra, Philisiwe
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145513 , vital:38445
- Description: My thesis combines short stories and flash fiction and a short novella collection. Working between reality and fantasy. The collection both engage the strangeness of magic in everyday life and explore other worlds. The stories uses different points of view to highlight the impossibility of a single stable reality. The writing is heavily influenced by Amos Tutuola (The Palm-Wine Drunkard) for his big imagination and how he draws from Yoruba folklore and mixes myth to fiction. Mica Dean Hicks (Electricity and other dreams) he writes with simplicity and his settings always believable yet with one sentence everything becomes a different world of seen and unseen. Margarita Karapanou (Kassandra and the wolf) The tone of the book captured me, how she balances heavy social theme around a young girl, the tone changes from chapter to chapter - from surreal to hallucinatory to mythic to something in between all these modes. She writes rape, but not once has she mentioned rape, yet she is writing about rape. Some books that revolutionized the way I see stories are (Kintu) written by Jennifer Nansubuga Makumbi and (Homegoing) by Yaa Gyasi. They both draw from histories yet contemporize their stories. Which my thesis intends to do that in stories such ‘MoonEyed Maiden’ and Sorana. Flying Cows and Other Traumas is an exploration of female body, when the sacredness of the female body is dehumanized by social injustices. Each story is a stand alone; the structure holds the through-line of the collection which conditions the complexities, the rawness and bluntness of how imbalance our society is. When the body is tainted with unfairness and powered down- how does one come up from that? The collection deals with poverty, sexual assault, systemic injustice, and sexism and some stories draw from personal experiences and fears. The female body is used as a hostage of shame and commodity and the female protagonists in ‘Flying Cows & Other Traumas sharpen their own stuff and shields to face their own injustices through blurring lines of mundanity and fantastical with experimental tone.
- Full Text:
- Date Issued: 2020
Formulation and evaluation of liposomal films for buccal delivery of antiretroviral drug
- Authors: Okafor, Nnamdi Ikemefuna
- Date: 2020
- Subjects: Liposomes , Highly active antiretroviral therapy , Antiretroviral agents , HIV infections -- Prevention
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/117161 , vital:34485
- Description: The human immune deficiency virus (HIV) infection has been ranked as one of the most devastating microbial infections in the world. This status is a result of the HIV rapid genetic variation, which limits discovery of a vaccine. Use application of antiretroviral therapy (ARVT) in treatment of the disease caused by the HIV infection (known as acquired immunodeficiency syndrome, HIV-AIDS) is frequently compromised by several factors such as the low bioavailability and severe adverse effects associated with the existing antiretroviral drugs (ARVDs). This underlines the need for controlling the pharmacokinetics profiles of ARVD using effective vehicles that can modify drug biodistribution. The same is true for many other conditions, where delivery systems can determine the success or failure of treatment by controlling pharmacokinetic and dynamic properties. The mucosal linings of the oral cavities in addition offer adorable route of administration for systematic drug delivery, improving drug therapeutic performance and often preferred by clinicians and patients. Liposomes are tiny spherical sacs of phospholipid molecules enclosing water droplets, formed (artificially) to carry drugs or other substances into the tissues by crossing and targeting to specific organelles. This work therefore focused on preparation of liposomes and liposomal buccal films (BFs) for potential buccal delivery of efavirenz, an ARVD model endowed with poor solubility and several side effects. The liposomes were prepared by thin film hydration method using crude soybean lecithin (CL) and cholesterol. Efavirenz loaded liposomes were evaluated for particle size, Zeta potential (ZP), morphology, encapsulation efficiency (EE%) and release kinetics studies. The physiochemical properties of the liposomes were also evaluated using Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), energy dispersity spectroscopy (EDS), and Fourier transform infrared (FTIR), while the formulation with the best encapsulation efficiency was used as the solvent medium for the buccal film formation. The buccal films were prepared using solvent casting method, where the liposomal suspension was used as the dispersing medium. The films were optimized for physical properties (thickness, weight variation and folding endurance) using digital Vernier calliper and digital weighing balance. The physiochemical properties of the selected BFs films made of Carbopol (CP) and its combination with Pluronic F127 (PF127) were further characterized using XRD, DSC, FTIR, Transmission Electron Microscopy (TEM), EDS and Scanning Electron Microscopy (SEM). The permeation study of the selected BFs was investigated using Franz diffusion cell. The BFs composed of CP alone or its combination with PF127 demonstrated much better bio-adhesive properties than the films made of other polymers (like Hydroxyl propyl methyl cellulose, HPMC) alone or in combination with PF127. The developed liposome formulation showed high encapsulation 98.8 ± 0.01 % in CL to cholesterol mass ratio of 1:1 and total lipid to drug mass ratio of 2:1. The average particle size 104.82 ± 2.29 nm and Zeta potential -50.33 ± 0.95 mV of these liposomes were found to be attractive for targeted delivery to the HIV infected cells. The CP based BFs (without and with PF127) exhibited good film thickness 0.88 ± 0.10 and 0.76 ± 0.14 mm, with weight uniformity 68.22 ± 1.04 and 86.28 ± 2. 16 mg, satisfactory flexibility values 258 and 321, and slightly acidic pH 6.43 ± 0.76 and 6.32 ± 0.01. The swelling percentage was found to be 50 % for CP film alone and 78 % for CP film with PF127. The cumulative amount of drug that permeated through the buccal epithelium over 24 hours was about 66 % from CP film alone and 75 % from CP film with PF127. Since no evidence of the liposomal encapsulation of EFV have been reported to our knowledge, we find the insights from the present study valuable as a set of preliminary data to encourage further investigations of the encapsulation and delivery of EFV like antiretrovirals for enhanced solubility, site targeting and prolonged release using crude soybean lecithin and mucoadhesive polymers, which holds some added economical values as naturally occurring lipid and polymeric mixtures as a promising delivery systems for buccal delivery of ARVDs.
- Full Text:
- Date Issued: 2020
- Authors: Okafor, Nnamdi Ikemefuna
- Date: 2020
- Subjects: Liposomes , Highly active antiretroviral therapy , Antiretroviral agents , HIV infections -- Prevention
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/117161 , vital:34485
- Description: The human immune deficiency virus (HIV) infection has been ranked as one of the most devastating microbial infections in the world. This status is a result of the HIV rapid genetic variation, which limits discovery of a vaccine. Use application of antiretroviral therapy (ARVT) in treatment of the disease caused by the HIV infection (known as acquired immunodeficiency syndrome, HIV-AIDS) is frequently compromised by several factors such as the low bioavailability and severe adverse effects associated with the existing antiretroviral drugs (ARVDs). This underlines the need for controlling the pharmacokinetics profiles of ARVD using effective vehicles that can modify drug biodistribution. The same is true for many other conditions, where delivery systems can determine the success or failure of treatment by controlling pharmacokinetic and dynamic properties. The mucosal linings of the oral cavities in addition offer adorable route of administration for systematic drug delivery, improving drug therapeutic performance and often preferred by clinicians and patients. Liposomes are tiny spherical sacs of phospholipid molecules enclosing water droplets, formed (artificially) to carry drugs or other substances into the tissues by crossing and targeting to specific organelles. This work therefore focused on preparation of liposomes and liposomal buccal films (BFs) for potential buccal delivery of efavirenz, an ARVD model endowed with poor solubility and several side effects. The liposomes were prepared by thin film hydration method using crude soybean lecithin (CL) and cholesterol. Efavirenz loaded liposomes were evaluated for particle size, Zeta potential (ZP), morphology, encapsulation efficiency (EE%) and release kinetics studies. The physiochemical properties of the liposomes were also evaluated using Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), energy dispersity spectroscopy (EDS), and Fourier transform infrared (FTIR), while the formulation with the best encapsulation efficiency was used as the solvent medium for the buccal film formation. The buccal films were prepared using solvent casting method, where the liposomal suspension was used as the dispersing medium. The films were optimized for physical properties (thickness, weight variation and folding endurance) using digital Vernier calliper and digital weighing balance. The physiochemical properties of the selected BFs films made of Carbopol (CP) and its combination with Pluronic F127 (PF127) were further characterized using XRD, DSC, FTIR, Transmission Electron Microscopy (TEM), EDS and Scanning Electron Microscopy (SEM). The permeation study of the selected BFs was investigated using Franz diffusion cell. The BFs composed of CP alone or its combination with PF127 demonstrated much better bio-adhesive properties than the films made of other polymers (like Hydroxyl propyl methyl cellulose, HPMC) alone or in combination with PF127. The developed liposome formulation showed high encapsulation 98.8 ± 0.01 % in CL to cholesterol mass ratio of 1:1 and total lipid to drug mass ratio of 2:1. The average particle size 104.82 ± 2.29 nm and Zeta potential -50.33 ± 0.95 mV of these liposomes were found to be attractive for targeted delivery to the HIV infected cells. The CP based BFs (without and with PF127) exhibited good film thickness 0.88 ± 0.10 and 0.76 ± 0.14 mm, with weight uniformity 68.22 ± 1.04 and 86.28 ± 2. 16 mg, satisfactory flexibility values 258 and 321, and slightly acidic pH 6.43 ± 0.76 and 6.32 ± 0.01. The swelling percentage was found to be 50 % for CP film alone and 78 % for CP film with PF127. The cumulative amount of drug that permeated through the buccal epithelium over 24 hours was about 66 % from CP film alone and 75 % from CP film with PF127. Since no evidence of the liposomal encapsulation of EFV have been reported to our knowledge, we find the insights from the present study valuable as a set of preliminary data to encourage further investigations of the encapsulation and delivery of EFV like antiretrovirals for enhanced solubility, site targeting and prolonged release using crude soybean lecithin and mucoadhesive polymers, which holds some added economical values as naturally occurring lipid and polymeric mixtures as a promising delivery systems for buccal delivery of ARVDs.
- Full Text:
- Date Issued: 2020
Generation of a virtual library of terpenes using graph theory, and its application in exploration of the mechanisms of terpene biosynthesis
- Authors: Dendera, Washington
- Date: 2020
- Subjects: Terpenes , Plants -- Metabolism , Computational biology , Bioinformatics , Organic compounds -- Synthesis , Monoterpenes , Molecular biology -- Computer simulation
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123453 , vital:35439
- Description: Terpenes form a large group of organic compounds which have proven to be of use to many living organisms being used by plants for metabolism (Pichersky and Gershenzon, 1934; McGarvey and Croteau, 1995; Gershenzon and Dudareva, 2007), defence or as a means to attract pollinators and also used by humans in medical, pharmaceutical and food industry (Bicas, Dionísio and Pastore, 2009; Marmulla and Harder, 2014; Kandi et al., 2015). Following on literature methods to generate chemical libraries using graph theoretic techniques, complete libraries of all possible terpene isomers have been constructed with the goal of construction of derivative libraries of possible carbocation intermediates which are important in the elucidation of mechanisms in the biosynthesis of terpenes. Virtual library generation of monoterpenes was first achieved by generating graphs of order 7, 8, 9 and 10 using the Nauty and Traces suite. These were screened and processed with a set of collated Python scripts written to recognize the graphs in text format and translate them to molecules, minimizing through Tinker whilst discarding graphs that violate chemistry laws. As a result of the computational time required only order 7 and order 10 graphs were processed. Out of the 873 graphs generated from order seven, 353 were converted to molecules and from the 11,7 million produced from order 10 half were processed resulting in the production of 442928 compounds (repeats included). For screening, 55 366 compounds were docked in the active site of limonene synthase; of these 2355 ligands had a good Vina docking score with a binding energy of between -7.0 and -7.4 kcal.mol-1. When these best docked molecules were overlaid in the active site a map of possible ligand positions within the active site of limonene synthase was traced out.
- Full Text:
- Date Issued: 2020
- Authors: Dendera, Washington
- Date: 2020
- Subjects: Terpenes , Plants -- Metabolism , Computational biology , Bioinformatics , Organic compounds -- Synthesis , Monoterpenes , Molecular biology -- Computer simulation
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123453 , vital:35439
- Description: Terpenes form a large group of organic compounds which have proven to be of use to many living organisms being used by plants for metabolism (Pichersky and Gershenzon, 1934; McGarvey and Croteau, 1995; Gershenzon and Dudareva, 2007), defence or as a means to attract pollinators and also used by humans in medical, pharmaceutical and food industry (Bicas, Dionísio and Pastore, 2009; Marmulla and Harder, 2014; Kandi et al., 2015). Following on literature methods to generate chemical libraries using graph theoretic techniques, complete libraries of all possible terpene isomers have been constructed with the goal of construction of derivative libraries of possible carbocation intermediates which are important in the elucidation of mechanisms in the biosynthesis of terpenes. Virtual library generation of monoterpenes was first achieved by generating graphs of order 7, 8, 9 and 10 using the Nauty and Traces suite. These were screened and processed with a set of collated Python scripts written to recognize the graphs in text format and translate them to molecules, minimizing through Tinker whilst discarding graphs that violate chemistry laws. As a result of the computational time required only order 7 and order 10 graphs were processed. Out of the 873 graphs generated from order seven, 353 were converted to molecules and from the 11,7 million produced from order 10 half were processed resulting in the production of 442928 compounds (repeats included). For screening, 55 366 compounds were docked in the active site of limonene synthase; of these 2355 ligands had a good Vina docking score with a binding energy of between -7.0 and -7.4 kcal.mol-1. When these best docked molecules were overlaid in the active site a map of possible ligand positions within the active site of limonene synthase was traced out.
- Full Text:
- Date Issued: 2020
Get sleep or get stumped: sleep behaviour in elite South African cricket players during competition
- Authors: McEwan, Kayla
- Date: 2020
- Subjects: Sleep -- Physiological aspects , Cricket players -- Health and hygiene , Cricket players -- South Africa -- Health and hygiene , Cricket -- Health aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/147950 , vital:38696
- Description: Introduction: Good sleep behaviour is associated with achieving optimal athletic performance and reducing the risk of injury. Elite cricket players have unique physical and cognitive demands, and must accommodate for congested competition and travel schedules (all of which increase the risk of disruptive sleep). Further, the political pressures and socioeconomic barriers in South African cricket could affect the sleep of the country’s elite players. Previous research in cricket has focussed on the impact that nutrition, equipment specifications, movement physiology and psychology could elicit on performance (where many professional teams hire support staff to supervise these disciplines); however, there is limited empirical application of sleep research in elite cricket players. Therefore, this study aimed to characterise the sleep behaviours of elite South African cricket players during periods of competition and investigate the relationship between pre-match sleep and cricket performance. Methods: A longitudinal field-based investigation was implemented to monitor the sleep behaviour of 26 elite South African cricket players (age: 28.6 ± 4.0 years; height: 1.8 ± 0.1 m; weight: 85.7 ± 10.8 kg; elite experience: 3.7 ± 4.0 years) during home and away competitive tours. The Morningness-Eveningness Questionnaire and Athlete Sleep Behaviour Questionnaire were administered to identify chronotype and poor sleep behaviours. Players completed an altered version of the Core Consensus Sleep Diary every morning post-travel, pre-match and post-match. Linear mixed model regression was used to compare differences in sleep variables between time-periods, match venues, player roles, match formats, sleep medication and racial groups. Spearman’s correlation (rs) was used to assess the relationship of substance use (alcohol and caffeine), age, elite experience and match performance with selected sleep indices. Statistical significance for all measures was accepted at p < 0.05. Hedge’s (g) were used as the measure of effect size. Results: Light-emitting technology use, effects of travel, late evening alcohol consumption and muscle soreness were the main factors that impacted sleep. Post-match total sleep time (06:31 ± 01:09) was significantly (p < 0.05) shorter compared to post-travel (07:53 ± 01:07; g = 1.19 [0.81;1.57]) and pre-match (08:43 ± 01:03; g = 1.97 [1.55;2.39]) total sleep time. Post-travel sleep onset latency and sleep efficiency were significantly (p < 0.05) shorter (g = 0.74 [0.29;1.29]) and higher (g = 1.35 [0.76;1.94]) at home than away. Although not significant (p > 0.05), allrounders took longer to fall asleep (g = 0.90 [0.23;1.57]), obtained less total sleep (0.76 [0.29;1.42]) and had lower morning freshness scores (g = 1.10 [0.42;1.78]) the night before a match compared to batsmen. Wake after sleep onset and get up time were moderately longer (g = 0.61 [0.22;1.26]) and later (g = 0.62 [0.27;1.17]) before. Twenty20 matches compared to One-Day International matches respectively. Further, sleep duration significantly declined from pre-match to post-match during the multi-day Test format (p = 0.04, g= 0.75 [0.40;1.12]). Late alcohol consumption was significantly (p < 0.05) correlated with a decrease in total sleep time, regardless of match venue (home: rs (49) = -0.69; away: rs (27) = -0.57). During the away condition, an increase in age was significantly associated with longer wake after sleep onset durations (rs (13) = 0.52, p = 0.0003), while greater elite experience was significantly associated with longer total sleep time (rs (72) = 0.36, p = 0.02). The non-sleep medication group took significantly longer to fall asleep compared to the sleep medication group during the first week of the away condition (p = 0.02, g = 0.75 [0.25;1.26]) particularly on nights following transmeridian travel. Although not significant ( p > 0.05), Asian/Indian players had moderately longer sleep onset latencies (g = 1.07 [0.66;1.47]), wake after sleep onset durations (g = 0.86 [0.42;1.29]), and lower subjective sleep quality (g = 0.86 [0.46;1.26]) and morning freshness scores (g = 0.89 [0.47;1.27]) compared to Whites. Similarly, Black Africans had moderately lower subjective sleep quality scores compared to Whites (g = 0.71 [0.43;0.97]). Longer sleep onset latencies and shorter total sleep times were significantly (p < 0.05) associated with poorer One-Day International (rs (28) = -0.57) and Test (rs (12) = 0.59) batting performances respectively. Higher subjective sleep quality scores were significantly associated with better Twenty20 bowling economies (rs (8) = -0.52). Discussion: There was no evidence of poor pre-match sleep behaviour, irrespective of venue; however, the most apparent disruption to sleep occurred post-match (similar to that found in other team-sports). Most disparities in sleep between match venues existed post-travel, with better sleep behaviour observed during the home condition. The differences in sleep patterns found in all three match formats were expected given the variations in format scheduling and duration. Although sleep medication was shown to promote better sleep, its long-term effectiveness was limited. The results promote the implementation of practical strategies aimed to reduce bedtime light-emitting technology use, late evening alcohol consumption and muscle pain. Inter-individual sleep behaviour was found between player roles, age, experience level and race. Moderate associations existed between sleep and markers of batting performance, specifically for the longer, strategic formats of the game. Conclusion: The current study provided new insight of the sleep behaviour in elite South African cricket players during competition. Individualized sleep monitoring practices are encouraged, with specific supervision over older, less experienced players as well as the racial minorities and allrounders of the team. The poor post-match sleep behaviour, together with the sleep and performance correlations, provide ideal opportunities for future interventions to focus on match recovery and the use sleep monitoring as a competitive advantage.
- Full Text:
- Date Issued: 2020
- Authors: McEwan, Kayla
- Date: 2020
- Subjects: Sleep -- Physiological aspects , Cricket players -- Health and hygiene , Cricket players -- South Africa -- Health and hygiene , Cricket -- Health aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/147950 , vital:38696
- Description: Introduction: Good sleep behaviour is associated with achieving optimal athletic performance and reducing the risk of injury. Elite cricket players have unique physical and cognitive demands, and must accommodate for congested competition and travel schedules (all of which increase the risk of disruptive sleep). Further, the political pressures and socioeconomic barriers in South African cricket could affect the sleep of the country’s elite players. Previous research in cricket has focussed on the impact that nutrition, equipment specifications, movement physiology and psychology could elicit on performance (where many professional teams hire support staff to supervise these disciplines); however, there is limited empirical application of sleep research in elite cricket players. Therefore, this study aimed to characterise the sleep behaviours of elite South African cricket players during periods of competition and investigate the relationship between pre-match sleep and cricket performance. Methods: A longitudinal field-based investigation was implemented to monitor the sleep behaviour of 26 elite South African cricket players (age: 28.6 ± 4.0 years; height: 1.8 ± 0.1 m; weight: 85.7 ± 10.8 kg; elite experience: 3.7 ± 4.0 years) during home and away competitive tours. The Morningness-Eveningness Questionnaire and Athlete Sleep Behaviour Questionnaire were administered to identify chronotype and poor sleep behaviours. Players completed an altered version of the Core Consensus Sleep Diary every morning post-travel, pre-match and post-match. Linear mixed model regression was used to compare differences in sleep variables between time-periods, match venues, player roles, match formats, sleep medication and racial groups. Spearman’s correlation (rs) was used to assess the relationship of substance use (alcohol and caffeine), age, elite experience and match performance with selected sleep indices. Statistical significance for all measures was accepted at p < 0.05. Hedge’s (g) were used as the measure of effect size. Results: Light-emitting technology use, effects of travel, late evening alcohol consumption and muscle soreness were the main factors that impacted sleep. Post-match total sleep time (06:31 ± 01:09) was significantly (p < 0.05) shorter compared to post-travel (07:53 ± 01:07; g = 1.19 [0.81;1.57]) and pre-match (08:43 ± 01:03; g = 1.97 [1.55;2.39]) total sleep time. Post-travel sleep onset latency and sleep efficiency were significantly (p < 0.05) shorter (g = 0.74 [0.29;1.29]) and higher (g = 1.35 [0.76;1.94]) at home than away. Although not significant (p > 0.05), allrounders took longer to fall asleep (g = 0.90 [0.23;1.57]), obtained less total sleep (0.76 [0.29;1.42]) and had lower morning freshness scores (g = 1.10 [0.42;1.78]) the night before a match compared to batsmen. Wake after sleep onset and get up time were moderately longer (g = 0.61 [0.22;1.26]) and later (g = 0.62 [0.27;1.17]) before. Twenty20 matches compared to One-Day International matches respectively. Further, sleep duration significantly declined from pre-match to post-match during the multi-day Test format (p = 0.04, g= 0.75 [0.40;1.12]). Late alcohol consumption was significantly (p < 0.05) correlated with a decrease in total sleep time, regardless of match venue (home: rs (49) = -0.69; away: rs (27) = -0.57). During the away condition, an increase in age was significantly associated with longer wake after sleep onset durations (rs (13) = 0.52, p = 0.0003), while greater elite experience was significantly associated with longer total sleep time (rs (72) = 0.36, p = 0.02). The non-sleep medication group took significantly longer to fall asleep compared to the sleep medication group during the first week of the away condition (p = 0.02, g = 0.75 [0.25;1.26]) particularly on nights following transmeridian travel. Although not significant ( p > 0.05), Asian/Indian players had moderately longer sleep onset latencies (g = 1.07 [0.66;1.47]), wake after sleep onset durations (g = 0.86 [0.42;1.29]), and lower subjective sleep quality (g = 0.86 [0.46;1.26]) and morning freshness scores (g = 0.89 [0.47;1.27]) compared to Whites. Similarly, Black Africans had moderately lower subjective sleep quality scores compared to Whites (g = 0.71 [0.43;0.97]). Longer sleep onset latencies and shorter total sleep times were significantly (p < 0.05) associated with poorer One-Day International (rs (28) = -0.57) and Test (rs (12) = 0.59) batting performances respectively. Higher subjective sleep quality scores were significantly associated with better Twenty20 bowling economies (rs (8) = -0.52). Discussion: There was no evidence of poor pre-match sleep behaviour, irrespective of venue; however, the most apparent disruption to sleep occurred post-match (similar to that found in other team-sports). Most disparities in sleep between match venues existed post-travel, with better sleep behaviour observed during the home condition. The differences in sleep patterns found in all three match formats were expected given the variations in format scheduling and duration. Although sleep medication was shown to promote better sleep, its long-term effectiveness was limited. The results promote the implementation of practical strategies aimed to reduce bedtime light-emitting technology use, late evening alcohol consumption and muscle pain. Inter-individual sleep behaviour was found between player roles, age, experience level and race. Moderate associations existed between sleep and markers of batting performance, specifically for the longer, strategic formats of the game. Conclusion: The current study provided new insight of the sleep behaviour in elite South African cricket players during competition. Individualized sleep monitoring practices are encouraged, with specific supervision over older, less experienced players as well as the racial minorities and allrounders of the team. The poor post-match sleep behaviour, together with the sleep and performance correlations, provide ideal opportunities for future interventions to focus on match recovery and the use sleep monitoring as a competitive advantage.
- Full Text:
- Date Issued: 2020
Growth and photosynthetic responses of Acacia (Vachellia) seedlings to atmospheric CO2 increased from glacial to current concentrations: underlying mechanisms and ecological implications
- Authors: Anderson, Bruce Maurice
- Date: 2020
- Subjects: Acacia vachellia , Acacia vachellia -- Growth , Acacia -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138182 , vital:37604
- Description: The African Acacia species Vachellia karroo, V. robusta, V. nilotica, and V. tortilis are some of the most invasive species implicated in bush encroachment and woody thickening of historically open savannas in southern Africa. This is partially explained by historic increases in atmospheric CO2 concentrations, which are proposed to have promoted the growth and survivorship of C3 tree seedlings relative to C4 grasses. However, the uniformity of CO2 responsiveness and differences among Vachellia species remain largely undetermined. Here we investigate the growth and photosynthetic responses of four Vachellia species, all implicated in woody encroachment, but originating from distinct climatic niches. Exposing these species to a range of sub-ambient CO2 concentrations (12 – 40 Pa) showed that V. karroo, V. robusta, V. nilotica and V. tortilis all responded strongly and fairly consistently to increasing CO2 concentrations, acting as a ‘functional type’ despite being selected from different geographic regions and having different climatic niches. Combined average net CO2 assimilation rates increased by 130% despite significant, but low levels of down-regulation and decreased stomatal conductance. The increased photosynthetic rates stimulated growth and biomass production in all compartments, with no significant differences in interspecific above and below ground allocation. Growth rates and dry biomass increased by 50% and 186%, respectively, while leaf level water use efficiency (ratio of net CO2 assimilation rate to transpiration rate) increased by an average of 218%. When this was scaled to the whole plant level, this stimulation was decreased to 80%. The decrease was the result of the CO2 stimulated increase in canopy areas, which increased leaf area for water loss. The seedlings’ total number of spinescent physical defenses, as well as the average mass and spine mass fraction also increased with rising CO2. These thicker spines could act as better deterrents against vertebrate browsers. Spine density was unchanged, however, showing that the increased spine numbers were associated with larger seedlings at higher CO2 rather than an increase in the number of spines per stem length. The stimulatory effects of increasing CO2 concentrations since the last glacial maximum and resultant increases in seedling growth and biomass are likely to have had important consequences for the survival and establishment of Acacia seedlings. Tolerance of drought and disturbance has been related to seedling size, hence stimulating the growth rate could confer disturbance tolerance and this tolerance would develop more rapidly with increasing CO2 concentrations. Furthermore, increased nitrogen and water use efficiency have the potential to support seedling establishment in environments where these resources would otherwise be limited at lower atmospheric CO2 concentrations. Resulting in a larger proportion of CO2 fertilization responsive woody seedlings surviving the seedling size classes, and persisting within historically open savannas. Where interspecific differences occurred they are likely to have arisen from adaptation to specific climates where these species are native and selection would have been driven by factors such climate, resource availability, levels of disturbance and competitive interactions. V. karroo had the highest growth rates and strong CO2 driven increases in biomass accumulation, despite having the lowest inherent photosynthetic rates. V. karroo also had the lowest increase in water use efficiency and high transpiration rates could potentially increase access to soil nutrients through mass flow. This species had the highest mean spine mass and showed significant increases in spine mass fraction at elevated CO2 concentrations, which may be important for deterring herbivores. V. robusta’s distribution to the mesic east coast of Africa suggests that water is an important limitation to its distribution. Hence, the CO2 stimulated increase in water use efficiency at both leaf and whole canopy level allows speculation that this may be an important driver of this species’ range expansion, which might continue if increasing levels of CO2 continue to promote water use efficiency. V. nilotica occupies a broad range of habitats, inhabiting large areas of the subtropics both north and south of the equator, with the strongest climatic correlates being the precipitation of the wettest quarter followed by high temperature seasonality. In response to increasing CO2, V. nilotica showed overall strong increases in growth, water use efficiency, and physical defenses. These responses may explain why V. nilotica has been such a successful encroacher in a broad range of habitats where limitations are likely to include multiple climatic factors and disturbances. V. tortilis has the widest distribution of all the species studied, covering broad ranges of Africa and only being excluded from the wettest parts of the equator and driest parts of the deserts. In these experiments this species showed the lowest biomass responsiveness to CO2, but had especially large increases in water use efficiency at both the leaf and canopy level. This may have been an important driver for this species’ encroachment into the more arid parts of its distribution, however this link will need to be verified with further experimentation.
- Full Text:
- Date Issued: 2020
- Authors: Anderson, Bruce Maurice
- Date: 2020
- Subjects: Acacia vachellia , Acacia vachellia -- Growth , Acacia -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138182 , vital:37604
- Description: The African Acacia species Vachellia karroo, V. robusta, V. nilotica, and V. tortilis are some of the most invasive species implicated in bush encroachment and woody thickening of historically open savannas in southern Africa. This is partially explained by historic increases in atmospheric CO2 concentrations, which are proposed to have promoted the growth and survivorship of C3 tree seedlings relative to C4 grasses. However, the uniformity of CO2 responsiveness and differences among Vachellia species remain largely undetermined. Here we investigate the growth and photosynthetic responses of four Vachellia species, all implicated in woody encroachment, but originating from distinct climatic niches. Exposing these species to a range of sub-ambient CO2 concentrations (12 – 40 Pa) showed that V. karroo, V. robusta, V. nilotica and V. tortilis all responded strongly and fairly consistently to increasing CO2 concentrations, acting as a ‘functional type’ despite being selected from different geographic regions and having different climatic niches. Combined average net CO2 assimilation rates increased by 130% despite significant, but low levels of down-regulation and decreased stomatal conductance. The increased photosynthetic rates stimulated growth and biomass production in all compartments, with no significant differences in interspecific above and below ground allocation. Growth rates and dry biomass increased by 50% and 186%, respectively, while leaf level water use efficiency (ratio of net CO2 assimilation rate to transpiration rate) increased by an average of 218%. When this was scaled to the whole plant level, this stimulation was decreased to 80%. The decrease was the result of the CO2 stimulated increase in canopy areas, which increased leaf area for water loss. The seedlings’ total number of spinescent physical defenses, as well as the average mass and spine mass fraction also increased with rising CO2. These thicker spines could act as better deterrents against vertebrate browsers. Spine density was unchanged, however, showing that the increased spine numbers were associated with larger seedlings at higher CO2 rather than an increase in the number of spines per stem length. The stimulatory effects of increasing CO2 concentrations since the last glacial maximum and resultant increases in seedling growth and biomass are likely to have had important consequences for the survival and establishment of Acacia seedlings. Tolerance of drought and disturbance has been related to seedling size, hence stimulating the growth rate could confer disturbance tolerance and this tolerance would develop more rapidly with increasing CO2 concentrations. Furthermore, increased nitrogen and water use efficiency have the potential to support seedling establishment in environments where these resources would otherwise be limited at lower atmospheric CO2 concentrations. Resulting in a larger proportion of CO2 fertilization responsive woody seedlings surviving the seedling size classes, and persisting within historically open savannas. Where interspecific differences occurred they are likely to have arisen from adaptation to specific climates where these species are native and selection would have been driven by factors such climate, resource availability, levels of disturbance and competitive interactions. V. karroo had the highest growth rates and strong CO2 driven increases in biomass accumulation, despite having the lowest inherent photosynthetic rates. V. karroo also had the lowest increase in water use efficiency and high transpiration rates could potentially increase access to soil nutrients through mass flow. This species had the highest mean spine mass and showed significant increases in spine mass fraction at elevated CO2 concentrations, which may be important for deterring herbivores. V. robusta’s distribution to the mesic east coast of Africa suggests that water is an important limitation to its distribution. Hence, the CO2 stimulated increase in water use efficiency at both leaf and whole canopy level allows speculation that this may be an important driver of this species’ range expansion, which might continue if increasing levels of CO2 continue to promote water use efficiency. V. nilotica occupies a broad range of habitats, inhabiting large areas of the subtropics both north and south of the equator, with the strongest climatic correlates being the precipitation of the wettest quarter followed by high temperature seasonality. In response to increasing CO2, V. nilotica showed overall strong increases in growth, water use efficiency, and physical defenses. These responses may explain why V. nilotica has been such a successful encroacher in a broad range of habitats where limitations are likely to include multiple climatic factors and disturbances. V. tortilis has the widest distribution of all the species studied, covering broad ranges of Africa and only being excluded from the wettest parts of the equator and driest parts of the deserts. In these experiments this species showed the lowest biomass responsiveness to CO2, but had especially large increases in water use efficiency at both the leaf and canopy level. This may have been an important driver for this species’ encroachment into the more arid parts of its distribution, however this link will need to be verified with further experimentation.
- Full Text:
- Date Issued: 2020
Hope in a small town
- Authors: Ngubelanga, Xolisa
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , South African fiction (English) -- History and criticism , Short stories, South African (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145089 , vital:38407
- Description: Writing has always experienced as the elite relative in the family of arts, especially among African artists and art consumers. Somehow writing has in past and to a great extent still is in the present been referred more than song, storytelling and dancing. Interrogating the past of colonization of African narratives I could point that this is the case because African expression had always packaged in a ‘come see the Africans are dancing, singing or storytelling. Listen to their clicks.’ Writing, however, could only be executed by those Africans of white assimilation with higher social status and missionary education. Among amaXhosa, the disparity of socially lesser African arts and that of the educated has been termed the narrative of Amaqaba and Amagqobhoka. Amaqaba being those whose stories have taken longer to be documented in modern means of writing but have been enriched through years of live telling. Amagqobhoka on the other hand who easily documented their narrative after having been trained in writing have enjoined the audience of readers and access into literary space longer.
- Full Text:
- Date Issued: 2020
- Authors: Ngubelanga, Xolisa
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , South African fiction (English) -- History and criticism , Short stories, South African (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145089 , vital:38407
- Description: Writing has always experienced as the elite relative in the family of arts, especially among African artists and art consumers. Somehow writing has in past and to a great extent still is in the present been referred more than song, storytelling and dancing. Interrogating the past of colonization of African narratives I could point that this is the case because African expression had always packaged in a ‘come see the Africans are dancing, singing or storytelling. Listen to their clicks.’ Writing, however, could only be executed by those Africans of white assimilation with higher social status and missionary education. Among amaXhosa, the disparity of socially lesser African arts and that of the educated has been termed the narrative of Amaqaba and Amagqobhoka. Amaqaba being those whose stories have taken longer to be documented in modern means of writing but have been enriched through years of live telling. Amagqobhoka on the other hand who easily documented their narrative after having been trained in writing have enjoined the audience of readers and access into literary space longer.
- Full Text:
- Date Issued: 2020
How relational and strategic leadership shape organizational culture
- Lebusa, Libuseng Mampolokeng
- Authors: Lebusa, Libuseng Mampolokeng
- Date: 2020
- Subjects: SOS Quthing Children's Village -- Management , Corporate culture , Corporate culture -- Lesotho -- Quthing , Leadership -- Lesotho -- Quthing , Nonprofit organizations -- Lesotho -- Quthing
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/166070 , vital:41326
- Description: The study aims at analysing how relational and strategic leadership shapes the culture of an organization, using as a case study the SOS Children’s Village Lesotho in Quthing District. As an International Federation, SOS Children’s Village espouses four values, namely Courage, Trust, Commitment, and Accountability. The case was selected because SOS Children’s Village’s performance in Lesotho has been outstanding, due to employee commitment in the organization. The review of the literature drew upon three theories: the theory of organizational culture by Schein (2010), which shed a light on cultural embedding mechanisms, the relational leadership components of Komives, S, Lucas, N, and McMahon, T (1998), and the strategic leadership roles of Ireland and Hitt (1999). This study adopted a deductive qualitative research method, where structured interviews supplemented with documents were used to collect data. Thematic analysis and pattern matching analysed the data with the aid of a pre-developed codebook that identify theoretical codes and themes in the data. The findings confirmed that with the use of cultural embedding mechanisms, relational and strategic leadership shaped the culture of commitment. The main characteristics of the culture of the commitment of SOS Quthing are punctuality, teamwork, and individual initiative. Relational and strategic leadership behaviours helped to create a culture of commitment through the fair and equitable allocation of resources, the inclusion of employees in decision making, having an orientation program for new employees, giving rewards and recognition, holding regular meetings, supervision, utilizing the online collaboration system and the systematic development of human capital. The literature supported the study results. The study acknowledges the limitations and delimitations of the research. The study’s contribution was in identifying how leadership behaviours operate through cultural embedding mechanisms to "identify" creates a culture of commitment. In conclusion, managerial recommendations were made for SOS to strengthen their leadership behaviours further and further research recommendations.
- Full Text:
- Date Issued: 2020
- Authors: Lebusa, Libuseng Mampolokeng
- Date: 2020
- Subjects: SOS Quthing Children's Village -- Management , Corporate culture , Corporate culture -- Lesotho -- Quthing , Leadership -- Lesotho -- Quthing , Nonprofit organizations -- Lesotho -- Quthing
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/166070 , vital:41326
- Description: The study aims at analysing how relational and strategic leadership shapes the culture of an organization, using as a case study the SOS Children’s Village Lesotho in Quthing District. As an International Federation, SOS Children’s Village espouses four values, namely Courage, Trust, Commitment, and Accountability. The case was selected because SOS Children’s Village’s performance in Lesotho has been outstanding, due to employee commitment in the organization. The review of the literature drew upon three theories: the theory of organizational culture by Schein (2010), which shed a light on cultural embedding mechanisms, the relational leadership components of Komives, S, Lucas, N, and McMahon, T (1998), and the strategic leadership roles of Ireland and Hitt (1999). This study adopted a deductive qualitative research method, where structured interviews supplemented with documents were used to collect data. Thematic analysis and pattern matching analysed the data with the aid of a pre-developed codebook that identify theoretical codes and themes in the data. The findings confirmed that with the use of cultural embedding mechanisms, relational and strategic leadership shaped the culture of commitment. The main characteristics of the culture of the commitment of SOS Quthing are punctuality, teamwork, and individual initiative. Relational and strategic leadership behaviours helped to create a culture of commitment through the fair and equitable allocation of resources, the inclusion of employees in decision making, having an orientation program for new employees, giving rewards and recognition, holding regular meetings, supervision, utilizing the online collaboration system and the systematic development of human capital. The literature supported the study results. The study acknowledges the limitations and delimitations of the research. The study’s contribution was in identifying how leadership behaviours operate through cultural embedding mechanisms to "identify" creates a culture of commitment. In conclusion, managerial recommendations were made for SOS to strengthen their leadership behaviours further and further research recommendations.
- Full Text:
- Date Issued: 2020
Identification of SANCDB compounds against G2019S and I2020T variants of leucine-rich repeat Kinase 2 (LRRK2) for the development of drugs against Parkinson’s Disease
- Authors: Baye, Bertha Cinthia
- Date: 2020
- Subjects: Antiparkinsonian agents , Parkinson's disease -- Treatment , Protein kinases , Parkinson's disease -- Chemotherapy , Molecules -- Models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138764 , vital:37671
- Description: Parkinson’s disease is a type of movement disorder that occurs when nerve cells in the brain stop producing dopamine. It is the second neurodegenerative disease affecting 1-2% of people above the ages of 65 years old. There is a worldwide prevalence of 7 to 10 million affected people of all cultures and race. Studies have shown that mutation that causes Parkinson’s disease result in increased kinase activity. The c.6055 G > A in exon 41 is the most prevalent LRRK2 variation which causes a substitution of glycine to serine in G2019S in the highly activated loop of its MAP kinase domain. The LRRK2 G2019S variant is the most common genetic determinant of Parkinson’s disease identified to date. This work focused on building accurate 3D models of the LRRK2 kinase domain, that were used for large-scale in silico docking against South African natural compounds from the South African Natural Compounds Database (SANCDB; https://sancdb.rubi.ru.ac.za/). Molecular docking was performed to identify compounds that formed interactions with the active site of the protein and had the lowest binding energy scores. Molecular dynamics simulations showed different movements of the protein-ligand complexes and behavioural difference of the wildtype and the variants, all three structures proved to be compact. Network analysis was done to study residue interactions, contact maps, dynamic cross correlations, average BC and average L were used to study the residue interactions and general residue contribution to the functioning of the protein..
- Full Text:
- Date Issued: 2020
- Authors: Baye, Bertha Cinthia
- Date: 2020
- Subjects: Antiparkinsonian agents , Parkinson's disease -- Treatment , Protein kinases , Parkinson's disease -- Chemotherapy , Molecules -- Models
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138764 , vital:37671
- Description: Parkinson’s disease is a type of movement disorder that occurs when nerve cells in the brain stop producing dopamine. It is the second neurodegenerative disease affecting 1-2% of people above the ages of 65 years old. There is a worldwide prevalence of 7 to 10 million affected people of all cultures and race. Studies have shown that mutation that causes Parkinson’s disease result in increased kinase activity. The c.6055 G > A in exon 41 is the most prevalent LRRK2 variation which causes a substitution of glycine to serine in G2019S in the highly activated loop of its MAP kinase domain. The LRRK2 G2019S variant is the most common genetic determinant of Parkinson’s disease identified to date. This work focused on building accurate 3D models of the LRRK2 kinase domain, that were used for large-scale in silico docking against South African natural compounds from the South African Natural Compounds Database (SANCDB; https://sancdb.rubi.ru.ac.za/). Molecular docking was performed to identify compounds that formed interactions with the active site of the protein and had the lowest binding energy scores. Molecular dynamics simulations showed different movements of the protein-ligand complexes and behavioural difference of the wildtype and the variants, all three structures proved to be compact. Network analysis was done to study residue interactions, contact maps, dynamic cross correlations, average BC and average L were used to study the residue interactions and general residue contribution to the functioning of the protein..
- Full Text:
- Date Issued: 2020
In vitro susceptibility of Staphylococcus aureus to porphyrin-silver mediated photodynamic antimicrobial chemotherapy
- Authors: Shabangu, Samuel Malewa
- Date: 2020
- Subjects: Porphyrins , Nanoparticles , Photochemotherapy , Drug resistance in microorganisms , Staphylococcus aureus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167476 , vital:41484
- Description: This work reports on the syntheses and characterization of symmetrical and unsymmetrical porphyrin complexes namely, 5,10,15,20-tetra(4-pyridyl)-porphyrinato zinc(II) (1), 5,10,15,20-tetrathienyl porphyrinato zinc(II) (2), 5-(4-hydroxyphenyl)-10, 15, 20-tris(2-thienyl) porphyrinato zinc(II) (3), 5-(4-carboxyphenyl)-10,15,20-tris(pentafluorophenyl)- porphyrinato zinc(II) (4), 5-(4-carboxyphenyl)-10,15,20-triphenyl-porphyrinato zinc(II) (5) and 5-(4-carboxyphenyl)-10, 15, 20-tris(2-thienyl)-porphyrinato zinc(II) (6). The synthesis of silver nanoparticles (AgNPs) was also undertaken in this research work. Complexes 1, 2, 3 and 6 were linked to oleic acid/oleylamine functionalized nanoparticles via self-assembly and 4-6 were linked via covalent interaction through an amide bond to glutathione capped AgNPs. The effect of nature of bond along with symmetry were investigated, of interest were the five membered thienyl substituents. The photophysical and photochemical behaviour of the complexes and their conjugates with AgNPs were investigated in dimethylformamide. The porphyrin and AgNPs conjugates afforded an increase in singlet oxygen quantum yield. Complexes 1-6 and their conjugates were used for photodynamic antimicrobial chemotherapy of Staphylococcus aureus. The antimicrobial studies were done in two different concentrations of 0.36 and 2.0 μg/mL. The thienyl substituted porphyrin complexes and their conjugates gave better photodynamic activity as compared to phenyl analogues
- Full Text:
- Date Issued: 2020
- Authors: Shabangu, Samuel Malewa
- Date: 2020
- Subjects: Porphyrins , Nanoparticles , Photochemotherapy , Drug resistance in microorganisms , Staphylococcus aureus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167476 , vital:41484
- Description: This work reports on the syntheses and characterization of symmetrical and unsymmetrical porphyrin complexes namely, 5,10,15,20-tetra(4-pyridyl)-porphyrinato zinc(II) (1), 5,10,15,20-tetrathienyl porphyrinato zinc(II) (2), 5-(4-hydroxyphenyl)-10, 15, 20-tris(2-thienyl) porphyrinato zinc(II) (3), 5-(4-carboxyphenyl)-10,15,20-tris(pentafluorophenyl)- porphyrinato zinc(II) (4), 5-(4-carboxyphenyl)-10,15,20-triphenyl-porphyrinato zinc(II) (5) and 5-(4-carboxyphenyl)-10, 15, 20-tris(2-thienyl)-porphyrinato zinc(II) (6). The synthesis of silver nanoparticles (AgNPs) was also undertaken in this research work. Complexes 1, 2, 3 and 6 were linked to oleic acid/oleylamine functionalized nanoparticles via self-assembly and 4-6 were linked via covalent interaction through an amide bond to glutathione capped AgNPs. The effect of nature of bond along with symmetry were investigated, of interest were the five membered thienyl substituents. The photophysical and photochemical behaviour of the complexes and their conjugates with AgNPs were investigated in dimethylformamide. The porphyrin and AgNPs conjugates afforded an increase in singlet oxygen quantum yield. Complexes 1-6 and their conjugates were used for photodynamic antimicrobial chemotherapy of Staphylococcus aureus. The antimicrobial studies were done in two different concentrations of 0.36 and 2.0 μg/mL. The thienyl substituted porphyrin complexes and their conjugates gave better photodynamic activity as compared to phenyl analogues
- Full Text:
- Date Issued: 2020
Ingqumbo yomthondo kukuzika kohlanga
- Authors: Mtirara, Zodwa
- Date: 2020
- Subjects: Women and literature , Feminism and literature , Gender identity in literature , Masculinity in literature , Sex role in literature , Xhosa poetry , South African poetry (English) , Sex discrimination against women
- Language: Xhosa, English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/154095 , vital:39562
- Description: Le yingqokelela yemibongo ebhentsisa ukutyeshelwa kobuntu nobuchule bamanina yinkolo yobuKrestu, kunye nenkolo yemveli okanye inkolo yesiNtu. Ikwenza oku ngokwaphula imithetho nemigaqo siseko yenkolo yobuKrestu nesiNtu sakwaXhosa malunga nokufanelekileyo ukuba owasetyhini akuthethe okanye akwenze. Ikwabhentsisa nokuhlukunyezwa kwabasetyhini, ibuza nemibuzo ngesimo esizifumana sikuso mva-nje. Ichukunyiswe bubomi bam kanye nobamanye amanina endiphila nawo ekuhlaleni. Ikubhentsisa ke oku ngokungenalusini njengoko imbongi uLesego Rampolokeng esenza. Izeka mzekweni ezibhalweni zooNtozakhe Shange, Diane Di Prima, Lidia Yuknavitch, noWame Molefhe. Iphikisa indlela ekubhalwe ngayo ngamanina ngooMema nooJolobe, isenza oko uNontsizi Mgqwetho angazange ade afikelele ukukwenza njengombhali wasetyhini.
- Full Text:
- Date Issued: 2020
- Authors: Mtirara, Zodwa
- Date: 2020
- Subjects: Women and literature , Feminism and literature , Gender identity in literature , Masculinity in literature , Sex role in literature , Xhosa poetry , South African poetry (English) , Sex discrimination against women
- Language: Xhosa, English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/154095 , vital:39562
- Description: Le yingqokelela yemibongo ebhentsisa ukutyeshelwa kobuntu nobuchule bamanina yinkolo yobuKrestu, kunye nenkolo yemveli okanye inkolo yesiNtu. Ikwenza oku ngokwaphula imithetho nemigaqo siseko yenkolo yobuKrestu nesiNtu sakwaXhosa malunga nokufanelekileyo ukuba owasetyhini akuthethe okanye akwenze. Ikwabhentsisa nokuhlukunyezwa kwabasetyhini, ibuza nemibuzo ngesimo esizifumana sikuso mva-nje. Ichukunyiswe bubomi bam kanye nobamanye amanina endiphila nawo ekuhlaleni. Ikubhentsisa ke oku ngokungenalusini njengoko imbongi uLesego Rampolokeng esenza. Izeka mzekweni ezibhalweni zooNtozakhe Shange, Diane Di Prima, Lidia Yuknavitch, noWame Molefhe. Iphikisa indlela ekubhalwe ngayo ngamanina ngooMema nooJolobe, isenza oko uNontsizi Mgqwetho angazange ade afikelele ukukwenza njengombhali wasetyhini.
- Full Text:
- Date Issued: 2020
Initiating biological control for Nymphaea mexicana zuccarini (Nymphaeaceae) in South Africa
- Authors: Reid, Megan
- Date: 2020
- Subjects: Nymphaea mexicana zuccarini -- Biological control -- South Africa , Nymphaeaceae -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144510 , vital:38352
- Description: Nymphaea mexicana Zuccarini (Nymphaeaceae) is an aquatic plant originating from south-eastern USA that is becoming increasingly invasive in South Africa as other invasive aquatic plants are being managed successfully through biological control. Mechanical and chemical control of aquatic weeds is expensive, damaging to the environment, and only effective in the short term, so biological control is more desirable as a management strategy for N. mexicana. The biological control of invasive alien plants requires that agents are host specific so that non-target risks are mitigated. For success to be achieved, it is important to ensure that the genetic structure of invasive populations is clarified so that agents can be collected from populations in the native range that match genetically to populations in the invasive range. This is especially important in cases where the morphology of invasive alien plants does not reflect genetic differences between populations. A previous study of the genetic structure of the invasive populations of N. mexicana in South Africa suggests the presence of hybrid forms of the plant in South Africa, with only one of these populations matching with samples from the native range. However, the study only used samples from two sites in the native range using amplified fragment length polymorphisms (AFLPs), so it was necessary to conduct further genetic analyses using samples from more sites in the native range. Hence, the first aim of this study was to develop a better understanding of the genetic structure of N. mexicana populations in the native and invaded range. Genetic samples were collected from sites in the native range during field surveys for potential biological control agents, and inter-simple sequence repeats (ISSRs) were used to compare the genetic structure of invasive and native populations of N. mexicana in South Africa. The results from these analyses suggest that seven of the 14 investigated invasive populations of N. mexicana in South Africa are genetically similar to populations in the native range, while the remaining seven populations are likely to be hybrid forms of the plant. This knowledge will be useful to target populations for biological control and highlights the need for further genetic analyses to determine the parentage of these hybrids so that biological control efforts are more likely to be successful. The initiation of a biological control programme requires that a series of steps are taken in order to maximise the likelihood that this form of intervention will be successful. The first few steps include: identification of the target weed and its genetic structure; exploration in the native range for potential biological control agents; and prioritisation of these agents based on factors such as climatic and genetic compatibility, feeding damage, abundance, and likely host range. Hence, the second aim of this study was to conduct surveys for potential biological control agents in the native range of N. mexicana, and to prioritise these agents. Field surveys were conducted between August and October in 2018 at 17 sites in Florida, Louisiana, and Texas, USA. Sites were selected based on climatic similarity of native sites compared to invasive sites by use of MaxEnt modelling. Native N. mexicana plants were searched for natural enemies, and these were prioritised based on feeding damage, abundance, incidence, and observations of field host range. Two species were prioritised: Bagous americanus LeConte (Coleoptera: Curculionidae) and Megamelus toddi Beamer (Hemiptera: Delphacidae). These species will be imported into quarantine facilities at Rhodes University for host specificity tests to be conducted. Understanding the factors that contribute to the successful establishment of biological control agents is important to improve the efficiency and reduce the costs incurred during the initiation of biological control programmes. Acquiring knowledge of the factors that predict the efficacy of biological control agents is similarly important, and these factors are discussed in the last chapter of this study. The challenges of the biological control of hybrids are also considered, and recommendations are made for the control of N. mexicana and other plants in South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Reid, Megan
- Date: 2020
- Subjects: Nymphaea mexicana zuccarini -- Biological control -- South Africa , Nymphaeaceae -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144510 , vital:38352
- Description: Nymphaea mexicana Zuccarini (Nymphaeaceae) is an aquatic plant originating from south-eastern USA that is becoming increasingly invasive in South Africa as other invasive aquatic plants are being managed successfully through biological control. Mechanical and chemical control of aquatic weeds is expensive, damaging to the environment, and only effective in the short term, so biological control is more desirable as a management strategy for N. mexicana. The biological control of invasive alien plants requires that agents are host specific so that non-target risks are mitigated. For success to be achieved, it is important to ensure that the genetic structure of invasive populations is clarified so that agents can be collected from populations in the native range that match genetically to populations in the invasive range. This is especially important in cases where the morphology of invasive alien plants does not reflect genetic differences between populations. A previous study of the genetic structure of the invasive populations of N. mexicana in South Africa suggests the presence of hybrid forms of the plant in South Africa, with only one of these populations matching with samples from the native range. However, the study only used samples from two sites in the native range using amplified fragment length polymorphisms (AFLPs), so it was necessary to conduct further genetic analyses using samples from more sites in the native range. Hence, the first aim of this study was to develop a better understanding of the genetic structure of N. mexicana populations in the native and invaded range. Genetic samples were collected from sites in the native range during field surveys for potential biological control agents, and inter-simple sequence repeats (ISSRs) were used to compare the genetic structure of invasive and native populations of N. mexicana in South Africa. The results from these analyses suggest that seven of the 14 investigated invasive populations of N. mexicana in South Africa are genetically similar to populations in the native range, while the remaining seven populations are likely to be hybrid forms of the plant. This knowledge will be useful to target populations for biological control and highlights the need for further genetic analyses to determine the parentage of these hybrids so that biological control efforts are more likely to be successful. The initiation of a biological control programme requires that a series of steps are taken in order to maximise the likelihood that this form of intervention will be successful. The first few steps include: identification of the target weed and its genetic structure; exploration in the native range for potential biological control agents; and prioritisation of these agents based on factors such as climatic and genetic compatibility, feeding damage, abundance, and likely host range. Hence, the second aim of this study was to conduct surveys for potential biological control agents in the native range of N. mexicana, and to prioritise these agents. Field surveys were conducted between August and October in 2018 at 17 sites in Florida, Louisiana, and Texas, USA. Sites were selected based on climatic similarity of native sites compared to invasive sites by use of MaxEnt modelling. Native N. mexicana plants were searched for natural enemies, and these were prioritised based on feeding damage, abundance, incidence, and observations of field host range. Two species were prioritised: Bagous americanus LeConte (Coleoptera: Curculionidae) and Megamelus toddi Beamer (Hemiptera: Delphacidae). These species will be imported into quarantine facilities at Rhodes University for host specificity tests to be conducted. Understanding the factors that contribute to the successful establishment of biological control agents is important to improve the efficiency and reduce the costs incurred during the initiation of biological control programmes. Acquiring knowledge of the factors that predict the efficacy of biological control agents is similarly important, and these factors are discussed in the last chapter of this study. The challenges of the biological control of hybrids are also considered, and recommendations are made for the control of N. mexicana and other plants in South Africa.
- Full Text:
- Date Issued: 2020
Integrating local knowledge when mediating learning of food preservation in a Namibian multicultural Grade 6 class
- Shetunyenga, Shetunyenga Fillipus
- Authors: Shetunyenga, Shetunyenga Fillipus
- Date: 2020
- Subjects: Food -- Preservation -- Study and teaching (Elementary) -- Namibia , Ethnoscience -- Study and teaching (Elementary) -- Namibia , Ethnoscience -- Namibia , Education, Elementary -- Namibia , Multicultural education -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/163602 , vital:41052
- Description: The challenge posed by multicultural classrooms has been acknowledged in many studies. Some scholars believe that the knowledge learners bring to school from their homes or community forms a basis for the knowledge to be acquired at school. That is, if learners’ cultural experiences and/or indigenous knowledge are integrated into teaching of science, learners might make good sense of science. Even though the Namibian National Curriculum has responded well to the calls of recognising and integrating indigeno us knowledge during teaching and learning, it has failed to provide guidance on how this should be done. Therefore, there is a need to minimise the gap between the intention of the National Curriculum and the implementation of this intended curriculum at classroom level. It is against this background that this study sought to investigate whether or not learners’ conceptions and attitudes are influenced by integrating local or indigenous knowledge when teaching food preservation in a Namibian multicultural classroom context. Underpinned by an interpretive paradigm, the study took the form of a mixed-method case study approach. It was conducted at an urban combined school in the Oshana region, Namibia. The sample consisted of 29 Grade 6 learners doing Agricultural Science, the grade 6 Agricultural Science teacher and four community members from different cultural groups. The community members were invited to demonstrate how they culturally preserve mahangu (wheat), fish, milk, and meat in their respective cultures. Data were generated using the pre-and post-intervention questionnaires, a group activity, observations (videotaped lessons) and learners’ journal reflections. Quantitative data from the pre- and post-intervention questionnaires were analysed deductively and presented in tables and graphs. On the other hand, a thematic approach was used to inductively analyse qualitative data, where Vygotsky’s (1978) socio-cultural theory was used as a theoretical lens focusing on culture, mediation, and social interactions. The findings of this study revealed that learners’ conceptions, attitudes, and interest shifted positively as a result of the integration of local or indigenous knowledge on food preservation. Additionally, during the presentations by the community members, learners were actively engaged, asking questions and showing interest in learning about other cultures. The study thus recommends that Agricultural Science or science teachers should, where possible, make efforts to integrate local or indigenous knowledge in their multicultural classrooms.
- Full Text:
- Date Issued: 2020
- Authors: Shetunyenga, Shetunyenga Fillipus
- Date: 2020
- Subjects: Food -- Preservation -- Study and teaching (Elementary) -- Namibia , Ethnoscience -- Study and teaching (Elementary) -- Namibia , Ethnoscience -- Namibia , Education, Elementary -- Namibia , Multicultural education -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/163602 , vital:41052
- Description: The challenge posed by multicultural classrooms has been acknowledged in many studies. Some scholars believe that the knowledge learners bring to school from their homes or community forms a basis for the knowledge to be acquired at school. That is, if learners’ cultural experiences and/or indigenous knowledge are integrated into teaching of science, learners might make good sense of science. Even though the Namibian National Curriculum has responded well to the calls of recognising and integrating indigeno us knowledge during teaching and learning, it has failed to provide guidance on how this should be done. Therefore, there is a need to minimise the gap between the intention of the National Curriculum and the implementation of this intended curriculum at classroom level. It is against this background that this study sought to investigate whether or not learners’ conceptions and attitudes are influenced by integrating local or indigenous knowledge when teaching food preservation in a Namibian multicultural classroom context. Underpinned by an interpretive paradigm, the study took the form of a mixed-method case study approach. It was conducted at an urban combined school in the Oshana region, Namibia. The sample consisted of 29 Grade 6 learners doing Agricultural Science, the grade 6 Agricultural Science teacher and four community members from different cultural groups. The community members were invited to demonstrate how they culturally preserve mahangu (wheat), fish, milk, and meat in their respective cultures. Data were generated using the pre-and post-intervention questionnaires, a group activity, observations (videotaped lessons) and learners’ journal reflections. Quantitative data from the pre- and post-intervention questionnaires were analysed deductively and presented in tables and graphs. On the other hand, a thematic approach was used to inductively analyse qualitative data, where Vygotsky’s (1978) socio-cultural theory was used as a theoretical lens focusing on culture, mediation, and social interactions. The findings of this study revealed that learners’ conceptions, attitudes, and interest shifted positively as a result of the integration of local or indigenous knowledge on food preservation. Additionally, during the presentations by the community members, learners were actively engaged, asking questions and showing interest in learning about other cultures. The study thus recommends that Agricultural Science or science teachers should, where possible, make efforts to integrate local or indigenous knowledge in their multicultural classrooms.
- Full Text:
- Date Issued: 2020
Investigating conceptual teaching of word problems through visualisation processes: a case of selected Grad 9 mathematics teachers
- Authors: John, Ssennyomo Bernard
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa , Pythagorean theorem -- Study and teaching (Secondary) , Mathematics teachers -- South Africa , Visualization
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/167497 , vital:41486
- Description: This study investigated how selected grade 9 mathematics teachers used visualisation strategies to conceptually teach Pythagoras' theorem word problems as a result of an intervention program. This research project is an integral component of the ViProMaths project whose goal is to research the effective use of visualisation strategies in the mathematics classroom in the Southern African region. This case study of mathematics teachers in the John Taolo Gaetsewe (JTG) District in the Northern Cape Province, used a social constructivist theory. The study is grounded within an interpretive paradigm and used an explanatory sequential mixed methods design. It surveyed eighty-seven mathematics teachers from all the secondary schools in the JTG District, focusing on their experiences when using visualisation approaches to teach Pythagoras’ theorem word problems. After the survey, three teachers purposively selected from three different schools in the district took part in the intervention programme. I used a survey questionnaire, classroom observations and interviews to collect the data from the study participants. The data were analysed quantitatively and qualitatively. The findings from survey data revealed that while teachers in the JTG District acknowledge the importance and value of visualisation strategies in the teaching of Pythagoras’ theorem word problems, many of them are either using visuals minimally or not using them at all. Challenges such as lack of resources in schools, time constrains, a lack of support from subject advisers, among others were noted. This thus necessitated a need for an intervention with some teachers in the district, specifically focusing on the use of visualisation tools and skills to teach Pythagoras’ theorem word problems for conceptual understanding. Lessons observations showed that all observed teachers used visual models to generate images and used the models to develop mathematical ideas. The teachers used the images to create platforms for classroom discussions. The discussions were driven by questions which teachers asked both for ascertaining learners’ prior knowledge and for finding out if they understood what the teachers were teaching. Interviews revealed that teachers’ perceptions had changed because they now know how to make and use different models to build on learners’ prior knowledge, extend what they are teaching to real life and make sense of Pythagoras’ proposition in multiple ways and to establish connections among a rich set of mathematics concepts when teaching Pythagoras’ theorem word problems. This study concludes that the use of visual strategies has the potential of enhancing conceptual teaching of Pythagoras’ theorem word problems. The implications for teachers are that learners need to be taught how to create visual representations (both internally and externally) of the relations between objects in a word problem as this will help them in maximising understanding. Furthermore, it is hoped that the results of this study could be used by various stake holders who include inter alia, mathematics subject advisers and teacher training institutions to improve the teaching of Pythagoras’ theorem word problems.
- Full Text:
- Date Issued: 2020
- Authors: John, Ssennyomo Bernard
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa , Pythagorean theorem -- Study and teaching (Secondary) , Mathematics teachers -- South Africa , Visualization
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/167497 , vital:41486
- Description: This study investigated how selected grade 9 mathematics teachers used visualisation strategies to conceptually teach Pythagoras' theorem word problems as a result of an intervention program. This research project is an integral component of the ViProMaths project whose goal is to research the effective use of visualisation strategies in the mathematics classroom in the Southern African region. This case study of mathematics teachers in the John Taolo Gaetsewe (JTG) District in the Northern Cape Province, used a social constructivist theory. The study is grounded within an interpretive paradigm and used an explanatory sequential mixed methods design. It surveyed eighty-seven mathematics teachers from all the secondary schools in the JTG District, focusing on their experiences when using visualisation approaches to teach Pythagoras’ theorem word problems. After the survey, three teachers purposively selected from three different schools in the district took part in the intervention programme. I used a survey questionnaire, classroom observations and interviews to collect the data from the study participants. The data were analysed quantitatively and qualitatively. The findings from survey data revealed that while teachers in the JTG District acknowledge the importance and value of visualisation strategies in the teaching of Pythagoras’ theorem word problems, many of them are either using visuals minimally or not using them at all. Challenges such as lack of resources in schools, time constrains, a lack of support from subject advisers, among others were noted. This thus necessitated a need for an intervention with some teachers in the district, specifically focusing on the use of visualisation tools and skills to teach Pythagoras’ theorem word problems for conceptual understanding. Lessons observations showed that all observed teachers used visual models to generate images and used the models to develop mathematical ideas. The teachers used the images to create platforms for classroom discussions. The discussions were driven by questions which teachers asked both for ascertaining learners’ prior knowledge and for finding out if they understood what the teachers were teaching. Interviews revealed that teachers’ perceptions had changed because they now know how to make and use different models to build on learners’ prior knowledge, extend what they are teaching to real life and make sense of Pythagoras’ proposition in multiple ways and to establish connections among a rich set of mathematics concepts when teaching Pythagoras’ theorem word problems. This study concludes that the use of visual strategies has the potential of enhancing conceptual teaching of Pythagoras’ theorem word problems. The implications for teachers are that learners need to be taught how to create visual representations (both internally and externally) of the relations between objects in a word problem as this will help them in maximising understanding. Furthermore, it is hoped that the results of this study could be used by various stake holders who include inter alia, mathematics subject advisers and teacher training institutions to improve the teaching of Pythagoras’ theorem word problems.
- Full Text:
- Date Issued: 2020