A mathematics teacher's response to a dilemma: 'I'm supposed to teach them in English but they don't understand'
- Robertson, Sally-Ann, Graven, Mellony
- Authors: Robertson, Sally-Ann , Graven, Mellony
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148889 , vital:38783 , https://doi.org/10.4102/sajce.v10i1.800
- Description: English is the dominant language in South African schools although it is the home language for less than 10% of the population. Many schools have yet to embrace the Language in Education Policy’s advocacy of additive bilingualism. This has led to a majority of the country’s children learning and being assessed through a language in which they lack proficiency. This article draws on second language teaching and learning theory to make a case for more systematic support for learners’ second language development and for legitimation of use of home language in mathematics classrooms where a different language is the official medium. The article shares empirical data from a South African Grade 4 mathematics teacher’s classroom to illuminate arguments in favour of additive bilingualism.
- Full Text:
- Date Issued: 2020
- Authors: Robertson, Sally-Ann , Graven, Mellony
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148889 , vital:38783 , https://doi.org/10.4102/sajce.v10i1.800
- Description: English is the dominant language in South African schools although it is the home language for less than 10% of the population. Many schools have yet to embrace the Language in Education Policy’s advocacy of additive bilingualism. This has led to a majority of the country’s children learning and being assessed through a language in which they lack proficiency. This article draws on second language teaching and learning theory to make a case for more systematic support for learners’ second language development and for legitimation of use of home language in mathematics classrooms where a different language is the official medium. The article shares empirical data from a South African Grade 4 mathematics teacher’s classroom to illuminate arguments in favour of additive bilingualism.
- Full Text:
- Date Issued: 2020
A mixed methods investigation of students’ attitudes towards statistics and quantitative research methods: a focus on postgraduate psychology students at a South African university
- Authors: Ngantweni, Xolelwa
- Date: 2020
- Subjects: Fetal alcohol spectrum disorders -- South Africa , Statistics , Psychology -- Research , College students -- South Africa -- Attitudes , Psychology -- Research -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140490 , vital:37894
- Description: Many University programs offer a course in either basic or intermediate statistics as part of the degree requirements prior to graduation (McGrath, Ferns, Greiner, Wanamaker and Brown, 2015). These statistics or quantitative research methods courses are integral in helping students gain vital skills in analysing quantitative data. Research (Schau, Stevens, Dauphinee, and Del Vecchio, 1995) does however indicate that most students have a perfunctory disposition towards these courses. My study sought to particularly investigate attitudes towards statistics and quantitative research methods amongst a sample of 61 postgraduate Psychology students at Rhodes University undertaking a ‘Quantitative Research Methods’ course as part of their degree offering. A mixed methods approach was used to investigate students’ attitudes towards statistics and quantitative research methods. The Survey of Attitudes Toward Statistics (SATS-36) (Schau, 2003) captured student’s attitudes towards statistics using a Likert Scale instrument; whereas detailed qualitative interviews accentuated findings from the SATS-36. Key quantitative findings from the SATS-36 including students’ perceptions of statistics being a difficult course as well as students having a low affect towards statistics are detailed. Key qualitative findings related to why students experience statistics anxiety such as students’ (1) fear of failing statistics, (2) The late introduction of statistics in the Psychology curriculum, and (3) The role of educator/s in alleviating or promoting feelings of statistics anxiety are noted. The significance of these findings as well as the contributions of the study to the teaching and learning of statistics and quantitative research methods courses at Rhodes University are explored, in light of other studies on the topic of statistics anxiety and attitudes towards statistics/ quantitative research methods.
- Full Text:
- Date Issued: 2020
- Authors: Ngantweni, Xolelwa
- Date: 2020
- Subjects: Fetal alcohol spectrum disorders -- South Africa , Statistics , Psychology -- Research , College students -- South Africa -- Attitudes , Psychology -- Research -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140490 , vital:37894
- Description: Many University programs offer a course in either basic or intermediate statistics as part of the degree requirements prior to graduation (McGrath, Ferns, Greiner, Wanamaker and Brown, 2015). These statistics or quantitative research methods courses are integral in helping students gain vital skills in analysing quantitative data. Research (Schau, Stevens, Dauphinee, and Del Vecchio, 1995) does however indicate that most students have a perfunctory disposition towards these courses. My study sought to particularly investigate attitudes towards statistics and quantitative research methods amongst a sample of 61 postgraduate Psychology students at Rhodes University undertaking a ‘Quantitative Research Methods’ course as part of their degree offering. A mixed methods approach was used to investigate students’ attitudes towards statistics and quantitative research methods. The Survey of Attitudes Toward Statistics (SATS-36) (Schau, 2003) captured student’s attitudes towards statistics using a Likert Scale instrument; whereas detailed qualitative interviews accentuated findings from the SATS-36. Key quantitative findings from the SATS-36 including students’ perceptions of statistics being a difficult course as well as students having a low affect towards statistics are detailed. Key qualitative findings related to why students experience statistics anxiety such as students’ (1) fear of failing statistics, (2) The late introduction of statistics in the Psychology curriculum, and (3) The role of educator/s in alleviating or promoting feelings of statistics anxiety are noted. The significance of these findings as well as the contributions of the study to the teaching and learning of statistics and quantitative research methods courses at Rhodes University are explored, in light of other studies on the topic of statistics anxiety and attitudes towards statistics/ quantitative research methods.
- Full Text:
- Date Issued: 2020
A model for the detection of breast cancer using machine learning and thermal images in a mobile environment
- Authors: Lennox, Nicholas
- Date: 2020
- Subjects: Breast -- Cancer -- Imaging , Breast -- Imaging Mobile communication systems
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/46097 , vital:39492
- Description: Breast cancer is the most common cancer amongst women and one of the deadliest. Various modalities exist which image the breasts, all with a focus on early detection; thermography is one such method. It is a non-invasive test, which is safe and can be used for a wide variety of breast densities. It functions by analysing thermal patterns captured via an infrared camera of the surface of the breast. Advances in infrared and mobile technology enable this modality to be mobile based; allowing a high degree of portability at a lower cost. Furthermore, as technology has improved, machine learning has played a larger role in medical practices by offering unbiased, consistent, and timely second opinions. Machine learning algorithms are able to classify medical images automatically if offered in the correct format. This study aims to provide a model, which integrates breast cancer detection, thermal imaging, machine learning, and mobile technology. The conceptual model is theorised from three literature studies regarding: identifiable aspects of breast cancer through thermal imaging, the mobile ecosystem, and classification using machine learning algorithms. The model is implemented and evaluated using an experiment designed to classify automatically thermal breast images of the same quality that mobile attachable thermal cameras are able to capture. The experiment contrasts various combinations of segmentation methods, extracted features, and classification algorithms. Promising results were shown in the experiment with a high degree of accuracy obtained. The successful results obtained from the experimentation process validates the feasibility of the model.
- Full Text:
- Date Issued: 2020
- Authors: Lennox, Nicholas
- Date: 2020
- Subjects: Breast -- Cancer -- Imaging , Breast -- Imaging Mobile communication systems
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/46097 , vital:39492
- Description: Breast cancer is the most common cancer amongst women and one of the deadliest. Various modalities exist which image the breasts, all with a focus on early detection; thermography is one such method. It is a non-invasive test, which is safe and can be used for a wide variety of breast densities. It functions by analysing thermal patterns captured via an infrared camera of the surface of the breast. Advances in infrared and mobile technology enable this modality to be mobile based; allowing a high degree of portability at a lower cost. Furthermore, as technology has improved, machine learning has played a larger role in medical practices by offering unbiased, consistent, and timely second opinions. Machine learning algorithms are able to classify medical images automatically if offered in the correct format. This study aims to provide a model, which integrates breast cancer detection, thermal imaging, machine learning, and mobile technology. The conceptual model is theorised from three literature studies regarding: identifiable aspects of breast cancer through thermal imaging, the mobile ecosystem, and classification using machine learning algorithms. The model is implemented and evaluated using an experiment designed to classify automatically thermal breast images of the same quality that mobile attachable thermal cameras are able to capture. The experiment contrasts various combinations of segmentation methods, extracted features, and classification algorithms. Promising results were shown in the experiment with a high degree of accuracy obtained. The successful results obtained from the experimentation process validates the feasibility of the model.
- Full Text:
- Date Issued: 2020
A morphogenetic study of ESD inclusion in Namibia’s Senior Primary English curriculum: a case study of the Khomas Region
- Authors: Malua, Anelly Ndapewa
- Date: 2020
- Subjects: Sustanable development -- Study and teaching -- Namibia , Environmental education -- Namibia , English language -- Study and teaching (Elementary) -- Namibia , Schools -- Namibia -- Curricula , Social change
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142865 , vital:38124
- Description: Education policies are designed to structure and direct the content and process of the education that citizens receive. This includes the advancement of the Education for Sustainable Development (ESD) policy in formal school curricula. If effectively implemented, ESD can be a significant educational intervention in southern African countries’ development trajectories. ESD incorporates the environmental, social and economic pillars of Sustainable Development and it has the potential to curb issues such as poverty reduction, climate change, biodiversity loss and unsustainable patterns of consumption and production. This qualitative case study investigated factors that have historically shaped, and currently shape, the emergence of ESD implementation in the Senior Primary English curriculum in the Khomas Region of Namibia. As a critical realist enquiry, the study sought to go beyond interpretations of the empirical to identify causal mechanisms in the domains of ‘the actual’ and ‘the real’. The study was guided by Margaret Archer’s theory of Morphogenesis / Morphostasis and her methodological tool of ‘analytical dualism’. The case record consisted of educational documents, teacher questionnaires and semistructured interviews. The morphogenetic approach highlighted how the implementation of ESD through the Senior Primary English curriculum from 1990 to 2018 was conditioned by the interplay of social and cultural structures and mechanisms and human agency, particularly teachers’ agency. The study revealed that although ESD implementation has emerged in the Senior Primary English curriculum, its emergence is not synchronous with the structural and agential entities. The findings point to a policy-structure mismatch which has relevance for policy makers, practitioners and other ESD stakeholders. The significance of this study is that it stands to fill a research gap regarding ESD implementation in Namibia’s Senior Primary English curriculum. The study makes recommendations for tangible ways to strengthen ESD practice in Senior Primary English teaching in Namibia such as increasing professional development opportunities to orientate teachers to ESD, strengthening networks that can build teacher agency in relation to ESD, and promoting a theme-based approach to ESD practice in English Language teaching.
- Full Text:
- Date Issued: 2020
- Authors: Malua, Anelly Ndapewa
- Date: 2020
- Subjects: Sustanable development -- Study and teaching -- Namibia , Environmental education -- Namibia , English language -- Study and teaching (Elementary) -- Namibia , Schools -- Namibia -- Curricula , Social change
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142865 , vital:38124
- Description: Education policies are designed to structure and direct the content and process of the education that citizens receive. This includes the advancement of the Education for Sustainable Development (ESD) policy in formal school curricula. If effectively implemented, ESD can be a significant educational intervention in southern African countries’ development trajectories. ESD incorporates the environmental, social and economic pillars of Sustainable Development and it has the potential to curb issues such as poverty reduction, climate change, biodiversity loss and unsustainable patterns of consumption and production. This qualitative case study investigated factors that have historically shaped, and currently shape, the emergence of ESD implementation in the Senior Primary English curriculum in the Khomas Region of Namibia. As a critical realist enquiry, the study sought to go beyond interpretations of the empirical to identify causal mechanisms in the domains of ‘the actual’ and ‘the real’. The study was guided by Margaret Archer’s theory of Morphogenesis / Morphostasis and her methodological tool of ‘analytical dualism’. The case record consisted of educational documents, teacher questionnaires and semistructured interviews. The morphogenetic approach highlighted how the implementation of ESD through the Senior Primary English curriculum from 1990 to 2018 was conditioned by the interplay of social and cultural structures and mechanisms and human agency, particularly teachers’ agency. The study revealed that although ESD implementation has emerged in the Senior Primary English curriculum, its emergence is not synchronous with the structural and agential entities. The findings point to a policy-structure mismatch which has relevance for policy makers, practitioners and other ESD stakeholders. The significance of this study is that it stands to fill a research gap regarding ESD implementation in Namibia’s Senior Primary English curriculum. The study makes recommendations for tangible ways to strengthen ESD practice in Senior Primary English teaching in Namibia such as increasing professional development opportunities to orientate teachers to ESD, strengthening networks that can build teacher agency in relation to ESD, and promoting a theme-based approach to ESD practice in English Language teaching.
- Full Text:
- Date Issued: 2020
A multimodal analysis of the representations of gender in contemporary South African children’s picture books produced by Book Dash
- Authors: Heydenrych, Ellen Frances
- Date: 2020
- Subjects: Book Dash (South Africa) , Picture books for children -- South Africa , Sex role in literature , Patriarchy in literature , Children's literature, South African (English) -- 21st century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/164284 , vital:41106
- Description: In response to a demand for quality children’s picture books written and published by South Africans for local children, Book Dash – a South African non-profit organisation – has devised a publishing model in which they produce high quality children’s picture books in a twelve-hour period. Their aim is to publish books that represent a diverse range of South African children. However, while their objective is to create books that are representative of many races, this representation happens through gendered characters. In this thesis, I explore the representation of gender in Book Dash’s picture books. I use a combination of visual social semiotics, narrative theory, and critical discourse analysis, specifically focusing on the gendered ways in which the characters are represented. My analysis of these books shows how complex it can be to contest regimes of representation that work to fix patriarchal discourses and gender inequality. My findings reveal a paradox in the representation of gender norms in female characters, as some girl child characters are represented in roles that challenge gender norms, while female adult characters are consistently represented as conforming to the patriarchal feminine ideal. There is also a notable lack of father figures in these books. Such portrayals may contribute to the perpetuation of patriarchal discourses and gender inequality, particularly if these books are held up as examples of equality.
- Full Text:
- Date Issued: 2020
- Authors: Heydenrych, Ellen Frances
- Date: 2020
- Subjects: Book Dash (South Africa) , Picture books for children -- South Africa , Sex role in literature , Patriarchy in literature , Children's literature, South African (English) -- 21st century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/164284 , vital:41106
- Description: In response to a demand for quality children’s picture books written and published by South Africans for local children, Book Dash – a South African non-profit organisation – has devised a publishing model in which they produce high quality children’s picture books in a twelve-hour period. Their aim is to publish books that represent a diverse range of South African children. However, while their objective is to create books that are representative of many races, this representation happens through gendered characters. In this thesis, I explore the representation of gender in Book Dash’s picture books. I use a combination of visual social semiotics, narrative theory, and critical discourse analysis, specifically focusing on the gendered ways in which the characters are represented. My analysis of these books shows how complex it can be to contest regimes of representation that work to fix patriarchal discourses and gender inequality. My findings reveal a paradox in the representation of gender norms in female characters, as some girl child characters are represented in roles that challenge gender norms, while female adult characters are consistently represented as conforming to the patriarchal feminine ideal. There is also a notable lack of father figures in these books. Such portrayals may contribute to the perpetuation of patriarchal discourses and gender inequality, particularly if these books are held up as examples of equality.
- Full Text:
- Date Issued: 2020
A multinational study of authors’ perceptions of and practical approaches to writing geography textbooks:
- Lee, Jongwon, Catling, Simon, Kidman, Gillian, Bednarz, Robert, Krause, Uwe, Martija, Andoni A, Ohnishi, Koji, Wilmot, P Dianne, Zecha, Stefane
- Authors: Lee, Jongwon , Catling, Simon , Kidman, Gillian , Bednarz, Robert , Krause, Uwe , Martija, Andoni A , Ohnishi, Koji , Wilmot, P Dianne , Zecha, Stefane
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158269 , vital:40168 , https://doi.org/10.1080/10382046.2020.1743931
- Description: Like all school textbooks, geography textbooks are authored. Almost all textbook research in and beyond geography has neglected their authors. This questionnaire-based multinational research project investigated the perceptions of 71 primary and secondary school geography textbook authors from seven countries in five continents. Though not intended as a definitive study, the findings identified several values and areas of expertise which many textbook authors in different countries held to be important for their work.
- Full Text:
- Date Issued: 2020
- Authors: Lee, Jongwon , Catling, Simon , Kidman, Gillian , Bednarz, Robert , Krause, Uwe , Martija, Andoni A , Ohnishi, Koji , Wilmot, P Dianne , Zecha, Stefane
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158269 , vital:40168 , https://doi.org/10.1080/10382046.2020.1743931
- Description: Like all school textbooks, geography textbooks are authored. Almost all textbook research in and beyond geography has neglected their authors. This questionnaire-based multinational research project investigated the perceptions of 71 primary and secondary school geography textbook authors from seven countries in five continents. Though not intended as a definitive study, the findings identified several values and areas of expertise which many textbook authors in different countries held to be important for their work.
- Full Text:
- Date Issued: 2020
A new approach to the biological monitoring of freshwater systems: Mapping nutrient loading in two South African rivers, a case study
- Motitsoe, Samuel N, Hill, Martin P, Avery, Trevor S, Hill, Jaclyn M
- Authors: Motitsoe, Samuel N , Hill, Martin P , Avery, Trevor S , Hill, Jaclyn M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444480 , vital:74244 , https://doi.org/10.1016/j.watres.2019.115391
- Description: Excessive addition of nitrogen (N) has threatened aquatic ecosystems for decades. Traditional water quality and biological monitoring assessment tools are widely used for monitoring nutrient loads and ecosystem health, but most of these methods cannot distinguish between different types and sources of pollution. This is a challenge, particularly when dealing with non-point sources of anthropogenic nitrogen inputs into freshwater systems. Recent laboratory studies using stable isotopic ratios (δ15N and C/N) of aquatic macrophytes (duckweed: Spirodela spp.) have shown successful differentiation and mapping between different N-sources and further, showed abilities to act as early warning indicators for environmental N-loading. Therefore, the aim of this study was to field test the potential of stable isotopic values of transplanted Spirodela spp. to map temporal and spatial N-loading variation and determine the main sources of N-loading in two river systems in the Eastern Cape Province of South Africa, using previously grown, isotopically calibrated and transplanted Spirodela plants, collected over a 13-month sampling period.
- Full Text:
- Date Issued: 2020
- Authors: Motitsoe, Samuel N , Hill, Martin P , Avery, Trevor S , Hill, Jaclyn M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444480 , vital:74244 , https://doi.org/10.1016/j.watres.2019.115391
- Description: Excessive addition of nitrogen (N) has threatened aquatic ecosystems for decades. Traditional water quality and biological monitoring assessment tools are widely used for monitoring nutrient loads and ecosystem health, but most of these methods cannot distinguish between different types and sources of pollution. This is a challenge, particularly when dealing with non-point sources of anthropogenic nitrogen inputs into freshwater systems. Recent laboratory studies using stable isotopic ratios (δ15N and C/N) of aquatic macrophytes (duckweed: Spirodela spp.) have shown successful differentiation and mapping between different N-sources and further, showed abilities to act as early warning indicators for environmental N-loading. Therefore, the aim of this study was to field test the potential of stable isotopic values of transplanted Spirodela spp. to map temporal and spatial N-loading variation and determine the main sources of N-loading in two river systems in the Eastern Cape Province of South Africa, using previously grown, isotopically calibrated and transplanted Spirodela plants, collected over a 13-month sampling period.
- Full Text:
- Date Issued: 2020
A new genus and three new species of South African Cicadettini (Hemiptera Cicadidae Cicadettinae).
- Sanborn, Allen F, Villet, Martin H
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441261 , vital:73871 , https://www.mapress.com/zt/article/view/zootaxa.4885.4.7
- Description: Ingcainyenzane irhiniensis n. gen., n. sp. and Ingcainyenzane nolukhanyoensis n. gen., n. sp. are described from Eastern Cape and Ingcainyenzane umgeniensis n. gen., n. sp. is described from KwaZulu-Natal, South Africa. Notes on its biology of the species and a key to species of the genus are also provided.
- Full Text:
- Date Issued: 2020
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441261 , vital:73871 , https://www.mapress.com/zt/article/view/zootaxa.4885.4.7
- Description: Ingcainyenzane irhiniensis n. gen., n. sp. and Ingcainyenzane nolukhanyoensis n. gen., n. sp. are described from Eastern Cape and Ingcainyenzane umgeniensis n. gen., n. sp. is described from KwaZulu-Natal, South Africa. Notes on its biology of the species and a key to species of the genus are also provided.
- Full Text:
- Date Issued: 2020
A new indole alkaloid and other constituents from Monodora minor and Uvaria tanzaniae: their antitrypanosomal and antiplasmodial evaluation
- Christopher, Robert, Mgani, Quintino A, Nyandoro, Stephen S, Rousseau, Amanda L, Isaacs, Michelle, Hoppe, Heinrich C
- Authors: Christopher, Robert , Mgani, Quintino A , Nyandoro, Stephen S , Rousseau, Amanda L , Isaacs, Michelle , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429347 , vital:72603 , xlink:href="https://doi.org/10.1080/14786419.2019.1710705"
- Description: Phytochemical investigation of the methanolic extract of Monodora minor Engl. and Diels (Annonaceae) stem bark yielded a new indole (E)-4-(1H-indol-5-yl)-but-3-en-2-one (1), a known indole 5-formyl-1H-indole (2) and an ubiquitous steroid sitosterol (3). The investigations of the methanolic extract of Uvaria tanzaniae Verdc. (Annonaceae) root bark yielded two previously reported C-benzylated dihydrochalcones namely uvaretin (4) and diuvaretin (5). Structures of the isolated compounds were elucidated based on NMR spectroscopy and high resolution electron ionization mass spectrometry (HR-EI-MS) data. All compounds were tested against Trypanosoma brucei brucei and Plasmodium falciparum. At a single concentration (20 μM) in the antitrypanosomal and antiplasmodial assays, compound 4 exhibited remarkable activities against T. brucei brucei and P. falciparum with percentage inhibition of 97.3% and 83.0% respectively, whereas compounds 1, 2, 3 and 5 were inactive. In a dose response antiplasmodial assay compound 4 exhibited moderate activity against P. falciparum with an IC50 value of 7.20 μM.
- Full Text:
- Date Issued: 2020
- Authors: Christopher, Robert , Mgani, Quintino A , Nyandoro, Stephen S , Rousseau, Amanda L , Isaacs, Michelle , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429347 , vital:72603 , xlink:href="https://doi.org/10.1080/14786419.2019.1710705"
- Description: Phytochemical investigation of the methanolic extract of Monodora minor Engl. and Diels (Annonaceae) stem bark yielded a new indole (E)-4-(1H-indol-5-yl)-but-3-en-2-one (1), a known indole 5-formyl-1H-indole (2) and an ubiquitous steroid sitosterol (3). The investigations of the methanolic extract of Uvaria tanzaniae Verdc. (Annonaceae) root bark yielded two previously reported C-benzylated dihydrochalcones namely uvaretin (4) and diuvaretin (5). Structures of the isolated compounds were elucidated based on NMR spectroscopy and high resolution electron ionization mass spectrometry (HR-EI-MS) data. All compounds were tested against Trypanosoma brucei brucei and Plasmodium falciparum. At a single concentration (20 μM) in the antitrypanosomal and antiplasmodial assays, compound 4 exhibited remarkable activities against T. brucei brucei and P. falciparum with percentage inhibition of 97.3% and 83.0% respectively, whereas compounds 1, 2, 3 and 5 were inactive. In a dose response antiplasmodial assay compound 4 exhibited moderate activity against P. falciparum with an IC50 value of 7.20 μM.
- Full Text:
- Date Issued: 2020
A novel dimeric exoglucanase (GH5_38)
- Mafa, Mpho S, Dirr, Heinrich W, Malgas, Samkelo, Krause, Rui W M, Pletschke, Brett I
- Authors: Mafa, Mpho S , Dirr, Heinrich W , Malgas, Samkelo , Krause, Rui W M , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193976 , vital:45412 , xlink:href="https://doi.org/10.3390/molecules25030746"
- Description: An exoglucanase (Exg-D) from the glycoside hydrolase family 5 subfamily 38 (GH5_38) was heterologously expressed and structurally and biochemically characterised at a molecular level for its application in alkyl glycoside synthesis. The purified Exg-D existed in both dimeric and monomeric forms in solution, which showed highest activity on mixed-linked β-glucan (88.0 and 86.7 U/mg protein, respectively) and lichenin (24.5 and 23.7 U/mg protein, respectively). They displayed a broad optimum pH range from 5.5 to 7 and a temperature optimum from 40 to 60 °C. Kinetic studies demonstrated that Exg-D had a higher affinity towards β-glucan, with a Km of 7.9 mg/mL and a kcat of 117.2 s−1, compared to lichenin which had a Km of 21.5 mg/mL and a kcat of 70.0 s−1. The circular dichroism profile of Exg-D showed that its secondary structure consisted of 11% α-helices, 36% β-strands and 53% coils. Exg-D performed transglycosylation using p-nitrophenyl cellobioside as a glycosyl donor and several primary alcohols as acceptors to produce methyl-, ethyl- and propyl-cellobiosides. These products were identified and quantified via thin-layer chromatography (TLC) and liquid chromatography–mass spectrometry (LC-MS). We concluded that Exg-D is a novel and promising oligomeric glycoside hydrolase for the one-step synthesis of alkyl glycosides with more than one monosaccharide unit.
- Full Text:
- Date Issued: 2020
- Authors: Mafa, Mpho S , Dirr, Heinrich W , Malgas, Samkelo , Krause, Rui W M , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193976 , vital:45412 , xlink:href="https://doi.org/10.3390/molecules25030746"
- Description: An exoglucanase (Exg-D) from the glycoside hydrolase family 5 subfamily 38 (GH5_38) was heterologously expressed and structurally and biochemically characterised at a molecular level for its application in alkyl glycoside synthesis. The purified Exg-D existed in both dimeric and monomeric forms in solution, which showed highest activity on mixed-linked β-glucan (88.0 and 86.7 U/mg protein, respectively) and lichenin (24.5 and 23.7 U/mg protein, respectively). They displayed a broad optimum pH range from 5.5 to 7 and a temperature optimum from 40 to 60 °C. Kinetic studies demonstrated that Exg-D had a higher affinity towards β-glucan, with a Km of 7.9 mg/mL and a kcat of 117.2 s−1, compared to lichenin which had a Km of 21.5 mg/mL and a kcat of 70.0 s−1. The circular dichroism profile of Exg-D showed that its secondary structure consisted of 11% α-helices, 36% β-strands and 53% coils. Exg-D performed transglycosylation using p-nitrophenyl cellobioside as a glycosyl donor and several primary alcohols as acceptors to produce methyl-, ethyl- and propyl-cellobiosides. These products were identified and quantified via thin-layer chromatography (TLC) and liquid chromatography–mass spectrometry (LC-MS). We concluded that Exg-D is a novel and promising oligomeric glycoside hydrolase for the one-step synthesis of alkyl glycosides with more than one monosaccharide unit.
- Full Text:
- Date Issued: 2020
A novel gold (I)-mediated intramolecular transamidation of benzoyl thiourea derivatives to form benzamides via dethiocyanation
- Odame, Felix, Woodcock, Guillaume, Hosten, Eric C, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Woodcock, Guillaume , Hosten, Eric C , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446988 , vital:74575 , xlink:href="https://doi.org/10.1016/j.jorganchem.2020.121359"
- Description: A novel gold(I)-mediated intramolecular transamidation of thiourea derivatives to yield benzamides via dethiocyanation have been achieved by the reaction of 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea derivatives in the presence of gold(I) precursors. The compounds have been characterized using IR, NMR, GC-MS and microanalysis. The single crystal XRD of 3-(1,3-benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (5), 3-(1,3-benzothiazol-2-yl)-1-(3-methoxybenzoyl)thiourea (6), N-(benzothiazol-2-yl)benzamide (10), N-(benzothiazol-2-yl)-3-chlorobenzamide (11), N-(benzothiazol-2-yl)-4-nitrobenzamide (12), N-(benzothiazol-2-yl)-3-bromobenzamide (14) have been discussed. The novel transformation is thought to proceed by a gold(I)-mediated intramolecular transamidation reaction which releases thiocyanate to yield the benzamide. Density functional theory calculations have been used to support the proposed mechanism for this transformation.
- Full Text:
- Date Issued: 2020
- Authors: Odame, Felix , Woodcock, Guillaume , Hosten, Eric C , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446988 , vital:74575 , xlink:href="https://doi.org/10.1016/j.jorganchem.2020.121359"
- Description: A novel gold(I)-mediated intramolecular transamidation of thiourea derivatives to yield benzamides via dethiocyanation have been achieved by the reaction of 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea derivatives in the presence of gold(I) precursors. The compounds have been characterized using IR, NMR, GC-MS and microanalysis. The single crystal XRD of 3-(1,3-benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (5), 3-(1,3-benzothiazol-2-yl)-1-(3-methoxybenzoyl)thiourea (6), N-(benzothiazol-2-yl)benzamide (10), N-(benzothiazol-2-yl)-3-chlorobenzamide (11), N-(benzothiazol-2-yl)-4-nitrobenzamide (12), N-(benzothiazol-2-yl)-3-bromobenzamide (14) have been discussed. The novel transformation is thought to proceed by a gold(I)-mediated intramolecular transamidation reaction which releases thiocyanate to yield the benzamide. Density functional theory calculations have been used to support the proposed mechanism for this transformation.
- Full Text:
- Date Issued: 2020
A novel, improved throughput bioassay for determining the delative speed of antimalarial drug action using fluorescent vitality probes
- Authors: Laming, Dustin
- Date: 2020
- Subjects: Plasmodium falciparum , Malaria -- Treatment -- Africa , Antimalarials , Malaria vaccine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/139902 , vital:37810
- Description: Malaria is one of the most prevalent diseases in Africa and Plasmodium falciparum is widely accepted as the most virulent of the malaria parasite species, with a fatality rate of 15 – 20 % of reported cases of infection. While various treatments have been accepted into early stage clinical trials, there has been little progress towards a proven vaccine. Pending a long-term solution, endemic countries rely heavily on the development of innovative drugs that are not only efficacious but are also quick acting. Traditional methods of evaluating antimalarial killing speeds via morphological assessments are inherently flawed by tedious, subjective interpretations of the heterogenous parasite morphology encountered in routine parasite culture conditions. This has led to the introduction of alternative assay formats to determine how rapidly compounds act on parasites in vitro: a parasite reduction ratio (PRR) assay that measures the recovery of parasite cultures from drug exposure; determining the shift in IC50 values of compounds when dose-response assays are carried out for different time periods; a bioluminescence relative rate of kill (BRRoK) assay that compares the extent to which compounds reduce firefly luciferase activity in transgenic parasites. Recent whole cell in vitro screening efforts have resulted in the generation of chemically diverse compound libraries such as the Medicines for Malaria Venture’s Pathogen Box, which houses 125 novel compounds with in vitro antiplasmodial activity. Assessing the relative killing speeds of these compounds would aid prioritizing fast-acting compounds that can be exploited as starting points for further development. This study aimed to develop a bioassay using the calcein-acetoxymethyl and propidium iodide fluorescent vitality probes, which would allow the relative speed of drug action on Plasmodium falciparum malaria parasites to be assessed and ranked in relation to each other using a quantitative, improved throughput approach. Initially applied to human (HeLa) cells, the assay was used to compare the relative speeds of action of 3 potential anti-cancer compounds by fluorescence microscopy. Subsequently adapted to P. falciparum, the assay was able to rank the relative speeds of action of standard antimalarials by fluorescence microscopy and two flow cytometry formats. Application of a multiwell flow cytometer increased throughput and enabled the assessment of experimental compounds, which included a set of artemisinin analogs and 125 antimalarial compounds in the MMV Pathogen Box. The latter culminated in the identification of five rapidly parasiticidal compounds in relation to the other compounds in the library, which may act as benchmark references for future studies and form the basis of the next generation of fast acting antimalarials that could be used to combat modern, resistant malaria.
- Full Text:
- Date Issued: 2020
- Authors: Laming, Dustin
- Date: 2020
- Subjects: Plasmodium falciparum , Malaria -- Treatment -- Africa , Antimalarials , Malaria vaccine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/139902 , vital:37810
- Description: Malaria is one of the most prevalent diseases in Africa and Plasmodium falciparum is widely accepted as the most virulent of the malaria parasite species, with a fatality rate of 15 – 20 % of reported cases of infection. While various treatments have been accepted into early stage clinical trials, there has been little progress towards a proven vaccine. Pending a long-term solution, endemic countries rely heavily on the development of innovative drugs that are not only efficacious but are also quick acting. Traditional methods of evaluating antimalarial killing speeds via morphological assessments are inherently flawed by tedious, subjective interpretations of the heterogenous parasite morphology encountered in routine parasite culture conditions. This has led to the introduction of alternative assay formats to determine how rapidly compounds act on parasites in vitro: a parasite reduction ratio (PRR) assay that measures the recovery of parasite cultures from drug exposure; determining the shift in IC50 values of compounds when dose-response assays are carried out for different time periods; a bioluminescence relative rate of kill (BRRoK) assay that compares the extent to which compounds reduce firefly luciferase activity in transgenic parasites. Recent whole cell in vitro screening efforts have resulted in the generation of chemically diverse compound libraries such as the Medicines for Malaria Venture’s Pathogen Box, which houses 125 novel compounds with in vitro antiplasmodial activity. Assessing the relative killing speeds of these compounds would aid prioritizing fast-acting compounds that can be exploited as starting points for further development. This study aimed to develop a bioassay using the calcein-acetoxymethyl and propidium iodide fluorescent vitality probes, which would allow the relative speed of drug action on Plasmodium falciparum malaria parasites to be assessed and ranked in relation to each other using a quantitative, improved throughput approach. Initially applied to human (HeLa) cells, the assay was used to compare the relative speeds of action of 3 potential anti-cancer compounds by fluorescence microscopy. Subsequently adapted to P. falciparum, the assay was able to rank the relative speeds of action of standard antimalarials by fluorescence microscopy and two flow cytometry formats. Application of a multiwell flow cytometer increased throughput and enabled the assessment of experimental compounds, which included a set of artemisinin analogs and 125 antimalarial compounds in the MMV Pathogen Box. The latter culminated in the identification of five rapidly parasiticidal compounds in relation to the other compounds in the library, which may act as benchmark references for future studies and form the basis of the next generation of fast acting antimalarials that could be used to combat modern, resistant malaria.
- Full Text:
- Date Issued: 2020
A personality-based surveillance model for Facebook apps
- Authors: Van der Schyff, Karl Izak
- Date: 2020
- Subjects: Facebook (Electronic resource) , Electronic surveillance -- Psychological aspects , Online social networks -- Psychological aspects , Social media -- Psychological aspects , Personality
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145534 , vital:38447
- Description: The surveillance of data through the use of Facebook Apps is an ongoing and persistent problem that impacts millions of users. Nonetheless, limited research has been conducted investigating to what extent a Facebook user’s personality influences their awareness of such surveillance practices. Thus, to understand this situation better, the current study inductively developed four propositions from secondary data sources as part of a detailed content analysis. Spanning three search and analysis phases the content analysis led to the development of the research model. Guided by the propositions and research questions, a questionnaire was developed based on the relevant constructs prescribed by the Theory of Planned Behaviour. This questionnaire was used, and a total of 651 responses were collected from Facebook users over the age of 18 years old and residing in the United States of America. Primary data took place at both a univariate and multivariate level with a specific focus on the development of a structural model. Interpretation of the structural model revealed that out of all the Big Five personality traits, Conscientiousness exhibited the strongest relationship with information security awareness followed by Openness to Experience and Neuroticism, respectively. The results further indicated that the model constructs based on attitude, social norms and awareness significantly influenced the intended use of Facebook Apps. The study also contributes by indicating which personality traits are most vulnerable to Facebook App surveillance. For example, it was found that individuals high in Conscientiousness are the least vulnerable with individuals high in Extraversion being the most vulnerable. Since the results indicate that not all the personality traits are significantly related to the model constructs, additional factors may contribute to App surveillance in this context. Concerning this, factors such as user apathy, information privacy, privacy concerns, control and Facebook dependency are discussed as a means to argue why this might be the case.
- Full Text:
- Date Issued: 2020
- Authors: Van der Schyff, Karl Izak
- Date: 2020
- Subjects: Facebook (Electronic resource) , Electronic surveillance -- Psychological aspects , Online social networks -- Psychological aspects , Social media -- Psychological aspects , Personality
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145534 , vital:38447
- Description: The surveillance of data through the use of Facebook Apps is an ongoing and persistent problem that impacts millions of users. Nonetheless, limited research has been conducted investigating to what extent a Facebook user’s personality influences their awareness of such surveillance practices. Thus, to understand this situation better, the current study inductively developed four propositions from secondary data sources as part of a detailed content analysis. Spanning three search and analysis phases the content analysis led to the development of the research model. Guided by the propositions and research questions, a questionnaire was developed based on the relevant constructs prescribed by the Theory of Planned Behaviour. This questionnaire was used, and a total of 651 responses were collected from Facebook users over the age of 18 years old and residing in the United States of America. Primary data took place at both a univariate and multivariate level with a specific focus on the development of a structural model. Interpretation of the structural model revealed that out of all the Big Five personality traits, Conscientiousness exhibited the strongest relationship with information security awareness followed by Openness to Experience and Neuroticism, respectively. The results further indicated that the model constructs based on attitude, social norms and awareness significantly influenced the intended use of Facebook Apps. The study also contributes by indicating which personality traits are most vulnerable to Facebook App surveillance. For example, it was found that individuals high in Conscientiousness are the least vulnerable with individuals high in Extraversion being the most vulnerable. Since the results indicate that not all the personality traits are significantly related to the model constructs, additional factors may contribute to App surveillance in this context. Concerning this, factors such as user apathy, information privacy, privacy concerns, control and Facebook dependency are discussed as a means to argue why this might be the case.
- Full Text:
- Date Issued: 2020
A psychobiographical case study: Amelia Dyer in a search for glory
- Authors: April, Heather
- Date: 2020
- Subjects: Serial murderers--Psychology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50857 , vital:43008
- Description: The study is a psychobiographical case study based on the life of a Victorian baby farmer Amelia Dyer (1837-1896). She was executed for the murder of babies who were placed in her care over a period of 30 years. Psychobiography is a qualitative method of enquiry which explores the life of a unique individual subject through the lens of a psychological theory for the purpose of creating a coherent psychological case study. The psychoanalytic theoretical lens of Karen Horney was used to trace the evolution of Amelia Dyer’s sense of self within the Victorian culture of respectability. Baby farming referred to an unregulated business of adoption and fostering of infants, mostly illegitimate infants for a fee. Insufficient social structures and support for unwed mothers and children encouraged the business practice as women had very little choice for childcare. Baby farming was open to abuse and exploitation and hundreds of babies lost their lives due to insufficient care or infanticide. Amelia Dyer showed special talents and creativity from a young age, was ambitious and wanted to be self-reliant in a culture that did not provide women with opportunities to live out their ambitions. Baby farming became a business venture for her in the early stages of her life which later evolved into sadistic abuse and murder of the infants. Her evolution from a creative and hardworking young girl to a sadistic murderer of children is what qualifies her as a suitable subject for the exploration of Karen Horney’s dynamic theory of neuroses and the development of the neurotic self within culture. Extensive biographical data was collected and processed into salient themes. The study integrates the theory of Karen Horney, the life experiences of Amelia Dyer and Victorian respectability and demonstrates the value of using psychobiography as the method of inquiry into the exploration of the unique individual. The findings of the study demonstrated that Amelia Dyer and her social context were inextricably bound by a vicious cycle of psychic and emotional vi conflicts related to fear, control and self-hatred by the internalization of gender stereotypes and norms. The contribution of the study as a whole rests with its demonstration of the value of a holistic and reflexive exploration of the unique individual woman. It demonstrates the value of Horney’s in-depth theoretical understanding of the ambivalent core of selfhood that lies behind observable acts of behavior. The study as a whole contributes towards building upon holistic and integrative therapeutic frameworks in the understanding of diversity amongst women and mothers in culture.
- Full Text:
- Date Issued: 2020
- Authors: April, Heather
- Date: 2020
- Subjects: Serial murderers--Psychology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50857 , vital:43008
- Description: The study is a psychobiographical case study based on the life of a Victorian baby farmer Amelia Dyer (1837-1896). She was executed for the murder of babies who were placed in her care over a period of 30 years. Psychobiography is a qualitative method of enquiry which explores the life of a unique individual subject through the lens of a psychological theory for the purpose of creating a coherent psychological case study. The psychoanalytic theoretical lens of Karen Horney was used to trace the evolution of Amelia Dyer’s sense of self within the Victorian culture of respectability. Baby farming referred to an unregulated business of adoption and fostering of infants, mostly illegitimate infants for a fee. Insufficient social structures and support for unwed mothers and children encouraged the business practice as women had very little choice for childcare. Baby farming was open to abuse and exploitation and hundreds of babies lost their lives due to insufficient care or infanticide. Amelia Dyer showed special talents and creativity from a young age, was ambitious and wanted to be self-reliant in a culture that did not provide women with opportunities to live out their ambitions. Baby farming became a business venture for her in the early stages of her life which later evolved into sadistic abuse and murder of the infants. Her evolution from a creative and hardworking young girl to a sadistic murderer of children is what qualifies her as a suitable subject for the exploration of Karen Horney’s dynamic theory of neuroses and the development of the neurotic self within culture. Extensive biographical data was collected and processed into salient themes. The study integrates the theory of Karen Horney, the life experiences of Amelia Dyer and Victorian respectability and demonstrates the value of using psychobiography as the method of inquiry into the exploration of the unique individual. The findings of the study demonstrated that Amelia Dyer and her social context were inextricably bound by a vicious cycle of psychic and emotional vi conflicts related to fear, control and self-hatred by the internalization of gender stereotypes and norms. The contribution of the study as a whole rests with its demonstration of the value of a holistic and reflexive exploration of the unique individual woman. It demonstrates the value of Horney’s in-depth theoretical understanding of the ambivalent core of selfhood that lies behind observable acts of behavior. The study as a whole contributes towards building upon holistic and integrative therapeutic frameworks in the understanding of diversity amongst women and mothers in culture.
- Full Text:
- Date Issued: 2020
A psychobiographical study of Maya Angelo
- Authors: De Waal, Leandra
- Date: 2020
- Subjects: Angelou, Maya
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46341 , vital:39569
- Description: Psychobiographies aim to gain a deeper understanding into the lives of notable or notorious individuals through the lens of a psychological theory. Thisstudy aimedto gain insight into the personality development of Maya Angelou through the useof Erikson’s Theory of PsychosocialDevelopment. The study exploresand describesher life experiences in terms of this theory, and understandsher life within her socio-historical context. Angelou is a renowned literary figure. Herjourney to becoming a writer was an arduous one, marked by great hardships from an early age. Despite early parental abandonment, childhood rape, exposure to racism, and difficulties in romantic relationships, she developed into a healthy adult who achieved much literary success and inspired individuals worldwide.Nonprobability purposive sampling was used to selectAngelou as the subjectand was madeon the basis of the researcher’s interest in Angelou’s life history.Datawas collected by triangulating multiple sources of informationand analysed using the approach developed by Miles and Huberman, which involves threesteps: data reduction, data display, and conclusion drawing and verification.The main findings suggest that Angelou progressed through Erikson’s eight stages successfully, despite some delays in negotiations of crises.
- Full Text:
- Date Issued: 2020
- Authors: De Waal, Leandra
- Date: 2020
- Subjects: Angelou, Maya
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46341 , vital:39569
- Description: Psychobiographies aim to gain a deeper understanding into the lives of notable or notorious individuals through the lens of a psychological theory. Thisstudy aimedto gain insight into the personality development of Maya Angelou through the useof Erikson’s Theory of PsychosocialDevelopment. The study exploresand describesher life experiences in terms of this theory, and understandsher life within her socio-historical context. Angelou is a renowned literary figure. Herjourney to becoming a writer was an arduous one, marked by great hardships from an early age. Despite early parental abandonment, childhood rape, exposure to racism, and difficulties in romantic relationships, she developed into a healthy adult who achieved much literary success and inspired individuals worldwide.Nonprobability purposive sampling was used to selectAngelou as the subjectand was madeon the basis of the researcher’s interest in Angelou’s life history.Datawas collected by triangulating multiple sources of informationand analysed using the approach developed by Miles and Huberman, which involves threesteps: data reduction, data display, and conclusion drawing and verification.The main findings suggest that Angelou progressed through Erikson’s eight stages successfully, despite some delays in negotiations of crises.
- Full Text:
- Date Issued: 2020
A psychobiography of Viktor Emil Frankl
- Authors: Bushkin, Hanan
- Date: 2020
- Subjects: Frankl, Viktor Emil
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46440 , vital:39566
- Description: The first study conducted in South Africa of a prominent figure traces back as far as 1939. Since then, extensive research has been done in the field of psychobiography, resulting in a growing interest in this field and evolving into an established research genre in South Africa. Despite the increase in the use of psychobiographies as a research approach internationally and specifically in South Africa, its use is still considered relatively under-utilised and, therefore, the pursuit of further development of psychobiographies in South Africa is required. In light of South Africa’s effort to promote and advance the use of psychobiographies, South African researchers may be motivated to continue studying significant and exceptional lives in South Africa and abroad. Viktor Frankl was selected for this study based on his uniqueness, significance and his interesting life. He is also considered an exceptional individual who has shaped modern psychological thinking. Frankl had written over 40 books on his theory and many studies have been conducted based on his existential theory. Frankl’s contribution to the academic world has been recognised and acknowledged by significant institutions through his own and others’ research. Although much has been written on the life and work of Frankl, none of the literature utilises specific psychological focus and no psychobiographical study of the life of Frankl exists. Therefore, the researcher selected Frankl as the subject for this psychobiography through purposive sampling. The aim of the study was to provide a psychological exploration and description of Frankl’s life against the backdrop of his socio-cultural context. In order to achieve this aim, the researcher employed two psychological frameworks to guide in the description and exploration of his life. The psychological frameworks included Levinson’s life structure theory of adult development and Frankl’s existential theory. The study aimed to describe Frankl’s development with the use of Levinson’s theory while describing how he attained meaning in his life with the use of his own existential theory. Due to the exploratory-descriptive nature of this study, the objective fell within the inductive research approach. The researcher utilised a systematic coding method to arrange the data. The theoretical framework of Levinson’s life structure theory guided the coding system, as well as the key concepts of Frankl’s existential theory. In addition, the researcher utilised Alexander’s guidelines for the extraction of salient data, together with McAdam’s methods and recommendations for managing the data. Lastly, the researcher followed the 12-step method of conducting a psychobiography, as proposed by Du Plessis. Findings from this study found a correlation between Frankl’s life and the eras and transitional periods as theorised by Levinson’s theory. The findings of this study, therefore, support the use of Levinson’s theory with regards to the time frames and its use in understanding Frankl’s development. Also, the researcher found that Levinson’s theory was useful in understanding Frankl’s personality development within his context throughout his lifespan. With regards to Frankl’s existential theory, the researcher found that the use of the theory was suitable in understanding Frankl’s search for meaning. Frankl’s concepts of freedom of will, will to meaning, meaning of life, existential vacuum, supra-meaning, dimensional ontology, the three triads and noö-dynamics assisted in explaining Frankl’s drive to find meaning in his life, take responsibility to attain such meaning and to strive for transcendence beyond his suffering. The researcher found Frankl’s theory useful in explaining his drive, motives, needs and patterns of behaviour within this context. The holistic and integrative approach of the study allowed for an in-depth exploration and description of Frankl’s life and development within his socio-historical context. In addition to contributing to the existing body of knowledge on Frankl, his life and his theory, the study also contributed to the growing field of psychobiographical research. The study acknowledged and highlighted that further in-depth examination of the lives of extraordinary personalities could significantly contribute to psychobiographical studies. Based on the psychological frameworks used to explore and describe Frankl’s life, recommendations are made for future research.
- Full Text:
- Date Issued: 2020
- Authors: Bushkin, Hanan
- Date: 2020
- Subjects: Frankl, Viktor Emil
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46440 , vital:39566
- Description: The first study conducted in South Africa of a prominent figure traces back as far as 1939. Since then, extensive research has been done in the field of psychobiography, resulting in a growing interest in this field and evolving into an established research genre in South Africa. Despite the increase in the use of psychobiographies as a research approach internationally and specifically in South Africa, its use is still considered relatively under-utilised and, therefore, the pursuit of further development of psychobiographies in South Africa is required. In light of South Africa’s effort to promote and advance the use of psychobiographies, South African researchers may be motivated to continue studying significant and exceptional lives in South Africa and abroad. Viktor Frankl was selected for this study based on his uniqueness, significance and his interesting life. He is also considered an exceptional individual who has shaped modern psychological thinking. Frankl had written over 40 books on his theory and many studies have been conducted based on his existential theory. Frankl’s contribution to the academic world has been recognised and acknowledged by significant institutions through his own and others’ research. Although much has been written on the life and work of Frankl, none of the literature utilises specific psychological focus and no psychobiographical study of the life of Frankl exists. Therefore, the researcher selected Frankl as the subject for this psychobiography through purposive sampling. The aim of the study was to provide a psychological exploration and description of Frankl’s life against the backdrop of his socio-cultural context. In order to achieve this aim, the researcher employed two psychological frameworks to guide in the description and exploration of his life. The psychological frameworks included Levinson’s life structure theory of adult development and Frankl’s existential theory. The study aimed to describe Frankl’s development with the use of Levinson’s theory while describing how he attained meaning in his life with the use of his own existential theory. Due to the exploratory-descriptive nature of this study, the objective fell within the inductive research approach. The researcher utilised a systematic coding method to arrange the data. The theoretical framework of Levinson’s life structure theory guided the coding system, as well as the key concepts of Frankl’s existential theory. In addition, the researcher utilised Alexander’s guidelines for the extraction of salient data, together with McAdam’s methods and recommendations for managing the data. Lastly, the researcher followed the 12-step method of conducting a psychobiography, as proposed by Du Plessis. Findings from this study found a correlation between Frankl’s life and the eras and transitional periods as theorised by Levinson’s theory. The findings of this study, therefore, support the use of Levinson’s theory with regards to the time frames and its use in understanding Frankl’s development. Also, the researcher found that Levinson’s theory was useful in understanding Frankl’s personality development within his context throughout his lifespan. With regards to Frankl’s existential theory, the researcher found that the use of the theory was suitable in understanding Frankl’s search for meaning. Frankl’s concepts of freedom of will, will to meaning, meaning of life, existential vacuum, supra-meaning, dimensional ontology, the three triads and noö-dynamics assisted in explaining Frankl’s drive to find meaning in his life, take responsibility to attain such meaning and to strive for transcendence beyond his suffering. The researcher found Frankl’s theory useful in explaining his drive, motives, needs and patterns of behaviour within this context. The holistic and integrative approach of the study allowed for an in-depth exploration and description of Frankl’s life and development within his socio-historical context. In addition to contributing to the existing body of knowledge on Frankl, his life and his theory, the study also contributed to the growing field of psychobiographical research. The study acknowledged and highlighted that further in-depth examination of the lives of extraordinary personalities could significantly contribute to psychobiographical studies. Based on the psychological frameworks used to explore and describe Frankl’s life, recommendations are made for future research.
- Full Text:
- Date Issued: 2020
A q-metholological approach to audience reception of public awareness messages on sexual violence
- Authors: Bennie, Rachel
- Date: 2020
- Subjects: Psychology -- Research -- Methodology , Psychology -- Research , Communication in social action -- South Africa , Psychology -- Research -- South Africa , Women -- Violence against -- South Africa , Women -- Violence against -- South Africa -- Prevention
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140805 , vital:37920
- Description: Public awareness poster campaigns are an often-used method for raising awareness about, and engaging audiences on the topic of rape and other forms of sexual violence (Potter, 2012). However, poster campaigns, as social artefacts, operate in a public arena in which numerous discourses about a phenomenon are produced, reproduced and interact with each other, with sometimes unintended/unanticipated discursive consequences (Böhmke, Bennie, Minnie, Moore, Pilusa & Pollock, 2015). How messages aimed at raising awareness of sexual violence are framed has the potential to reproduce dominant social narratives and gendered subject positions in ways that reinforce notions of men as active sexual agents and potential perpetrators, and women as sexually passive and potential victims (Gavey, 2005). Other approaches, such as bystander intervention, seek to move away from a focus on victims and perpetrators to emphasise the role that community members can play in risk detection, safety promotion and the prevention of sexual violence (McMahon & Banyard, 2012). Since a range of possible messages about sexual violence can be communicated through poster campaigns, it is important to critically examine the content and orientation of campaign material. This study focused on intended audience views regarding messages about sexual violence contained in anti-sexual violence poster materials. The purpose was to collaborate with a selected audience to better understand which messages are effective and which strategies of communication are perceived to be less so. Through the use of Q-methodology, volunteer participants were invited to express their opinions in relation to messages about sexual violence from a range of posters from several international campaigns. The analysis focused on uncovering the discursive subject positions that participants’ express in their attitudinal responses to the poster messages, providing not only a description of these positions, but also illustrating the level of resonance that the poster messages may find with intended audiences. The aim of the study is to potentially inform the development of more focused campaign material, tailored to the specific context from which participants were drawn. Analysis shows clear patterns of audience resistance towards stereotypical representations of sexual violence and messages that are geared towards the simple prohibition of behaviours. The findings highlight the need for the development of alternative strategies of engagement that focus on specific engagement with understandings of sexual violence in the context of intimate and/or acquaintance relationships and which are aimed at inviting audiences to take up a position in relation to sexual violence phenomena that troubles the reproduction of received notions of gendered subjectivities and (hetero) sexuality
- Full Text:
- Date Issued: 2020
- Authors: Bennie, Rachel
- Date: 2020
- Subjects: Psychology -- Research -- Methodology , Psychology -- Research , Communication in social action -- South Africa , Psychology -- Research -- South Africa , Women -- Violence against -- South Africa , Women -- Violence against -- South Africa -- Prevention
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140805 , vital:37920
- Description: Public awareness poster campaigns are an often-used method for raising awareness about, and engaging audiences on the topic of rape and other forms of sexual violence (Potter, 2012). However, poster campaigns, as social artefacts, operate in a public arena in which numerous discourses about a phenomenon are produced, reproduced and interact with each other, with sometimes unintended/unanticipated discursive consequences (Böhmke, Bennie, Minnie, Moore, Pilusa & Pollock, 2015). How messages aimed at raising awareness of sexual violence are framed has the potential to reproduce dominant social narratives and gendered subject positions in ways that reinforce notions of men as active sexual agents and potential perpetrators, and women as sexually passive and potential victims (Gavey, 2005). Other approaches, such as bystander intervention, seek to move away from a focus on victims and perpetrators to emphasise the role that community members can play in risk detection, safety promotion and the prevention of sexual violence (McMahon & Banyard, 2012). Since a range of possible messages about sexual violence can be communicated through poster campaigns, it is important to critically examine the content and orientation of campaign material. This study focused on intended audience views regarding messages about sexual violence contained in anti-sexual violence poster materials. The purpose was to collaborate with a selected audience to better understand which messages are effective and which strategies of communication are perceived to be less so. Through the use of Q-methodology, volunteer participants were invited to express their opinions in relation to messages about sexual violence from a range of posters from several international campaigns. The analysis focused on uncovering the discursive subject positions that participants’ express in their attitudinal responses to the poster messages, providing not only a description of these positions, but also illustrating the level of resonance that the poster messages may find with intended audiences. The aim of the study is to potentially inform the development of more focused campaign material, tailored to the specific context from which participants were drawn. Analysis shows clear patterns of audience resistance towards stereotypical representations of sexual violence and messages that are geared towards the simple prohibition of behaviours. The findings highlight the need for the development of alternative strategies of engagement that focus on specific engagement with understandings of sexual violence in the context of intimate and/or acquaintance relationships and which are aimed at inviting audiences to take up a position in relation to sexual violence phenomena that troubles the reproduction of received notions of gendered subjectivities and (hetero) sexuality
- Full Text:
- Date Issued: 2020
A Ranking Framework for Higher Education Institutions in South Africa
- Authors: Kanyutu, Teresia Watiri
- Date: 2020
- Subjects: Education, Higher -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/48246 , vital:40746
- Description: In the past 16 years, the use of League Tables and Rankings (LTRs) as a tool to rank or measure the performance of Higher Education Institutions (HEIs) has grown in popularity. As a global practice, LTR outcomes are influencing how policies are developed and implemented within the Higher Education (HE) sector. Studies indicate that based on individual information requirements, HE stakeholders are using LTRs to compare HEIs with each other and make informed comparisons and decisions. University directors use LTRs as a basis for institutional strategic planning, reputation building and policy making, while students use LTRs to compare HEIs and make university of choice decisions. Further studies confirm that governments use LTRs for national higher education policy making, university funding, foreign partnerships and resource allocation. Globally and at a national level, the higher education sector has witnessed policy and structural changes, many of which are due to the increase in the use of international rankings and league tables. Despite the opportunities presented by participating in the production of and using LTRs, the ranking practice is contentious. Amongst the issues disputed by the HE stakeholders are the methodologies and criteria used in the production and publication of LTRs. Higher education experts argue that LTRs tend to favour institutional research output and ignore the teaching and learning function of HEIs. As a result, the ranking criteria differ across the higher education ranking institutions and their publication outcomes, which causes skepticism across the HE sector. Research indicates that these ranking criteria are often discussed from the standpoint of governments, the higher education management and the ranking institutions producing these LTR publications. The opinions of the students on the suitable ranking criteria used by ranking institutions lack. This study aims to address that gap. This study investigates the applicable criteria for ranking HEIs in South Africa, from the perspective of students. Building on the existing ranking criteria for three global and popular ranking institutions namely, Academic Ranking of World Universities (ARWU), Times Higher Education World University Ranking (THEWUR) and Quacquarelli Symonds World University Ranking (QSWUR), the study poses the question; “What framework can be used to rank HEIs in South Africa, from a student’s perspective?” The study argues that although some HEIs in South Africa have in the past and most recently appeared in the global LTRs, the current choice of ranking criteria fails to consider the perspectives of the students, who are major consumers of LTRs and important stakeholders in the HE sector. A positivistic research method was used, based on a review of literature on the current ranking criteria for the selected global ranking institutions. An empirical study was conducted amongst students in a South African Comprehensive University. An online survey was distributed through convenient and snowball sampling, where the students were requested to participate in the survey and share the questionnaire link with others. Eight hundred and eighty six (886) responses were received and used for the data analyses of this study.
- Full Text:
- Date Issued: 2020
- Authors: Kanyutu, Teresia Watiri
- Date: 2020
- Subjects: Education, Higher -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/48246 , vital:40746
- Description: In the past 16 years, the use of League Tables and Rankings (LTRs) as a tool to rank or measure the performance of Higher Education Institutions (HEIs) has grown in popularity. As a global practice, LTR outcomes are influencing how policies are developed and implemented within the Higher Education (HE) sector. Studies indicate that based on individual information requirements, HE stakeholders are using LTRs to compare HEIs with each other and make informed comparisons and decisions. University directors use LTRs as a basis for institutional strategic planning, reputation building and policy making, while students use LTRs to compare HEIs and make university of choice decisions. Further studies confirm that governments use LTRs for national higher education policy making, university funding, foreign partnerships and resource allocation. Globally and at a national level, the higher education sector has witnessed policy and structural changes, many of which are due to the increase in the use of international rankings and league tables. Despite the opportunities presented by participating in the production of and using LTRs, the ranking practice is contentious. Amongst the issues disputed by the HE stakeholders are the methodologies and criteria used in the production and publication of LTRs. Higher education experts argue that LTRs tend to favour institutional research output and ignore the teaching and learning function of HEIs. As a result, the ranking criteria differ across the higher education ranking institutions and their publication outcomes, which causes skepticism across the HE sector. Research indicates that these ranking criteria are often discussed from the standpoint of governments, the higher education management and the ranking institutions producing these LTR publications. The opinions of the students on the suitable ranking criteria used by ranking institutions lack. This study aims to address that gap. This study investigates the applicable criteria for ranking HEIs in South Africa, from the perspective of students. Building on the existing ranking criteria for three global and popular ranking institutions namely, Academic Ranking of World Universities (ARWU), Times Higher Education World University Ranking (THEWUR) and Quacquarelli Symonds World University Ranking (QSWUR), the study poses the question; “What framework can be used to rank HEIs in South Africa, from a student’s perspective?” The study argues that although some HEIs in South Africa have in the past and most recently appeared in the global LTRs, the current choice of ranking criteria fails to consider the perspectives of the students, who are major consumers of LTRs and important stakeholders in the HE sector. A positivistic research method was used, based on a review of literature on the current ranking criteria for the selected global ranking institutions. An empirical study was conducted amongst students in a South African Comprehensive University. An online survey was distributed through convenient and snowball sampling, where the students were requested to participate in the survey and share the questionnaire link with others. Eight hundred and eighty six (886) responses were received and used for the data analyses of this study.
- Full Text:
- Date Issued: 2020
A reappraisal of the origin of the Hotazel Fe-Mn Formation in an evolving early Earth system through the application of mineral-specific geochemistry, speciation techniques and stable isotope systematics
- Authors: Mhlanga, Xolane Reginald
- Date: 2020
- Subjects: Manganese ores -- South Africa -- Hotazel , Manganese ores -- Geology , Iron ores -- South Africa -- Hotazel , Iron ores -- Geology , Geochemistry -- South Africa -- Hotazel , Isotope geology -- South Africa -- Hotazel , Geology, Stratigraphic -- Archaean , Geology, Stratigraphic -- Proterozoic , Transvaal Supergroup (South Africa) , Great Oxidation Event
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146123 , vital:38497
- Description: Marine chemical sediments such as Banded Iron Formations deposited during the Archean-Palaeoproterozoic are studied extensively because they represent a period in the development of the Earth’s early history where the atmospheric O₂ content was below the present levels (PAL) of 21%. Prior to the Great Oxidation Event (GOE) at ca. 2.4 Ga, highly ferruginous and anoxic marine environments were dominated by extensive BIF deposition such as that of the Griqualand West Basin of the Transvaal Supergroup in South Africa. This basin is also thought to record the transition into the first rise of atmospheric O₂ in our planet, from the Koegas Subgroup to the Hotazel Formation dated at ca. 2.43 Ga (Gumsley et al., 2017). Two drill cores from the north eastern part of the Kalahari Manganese Field characterized by a well-preserved and complete intersection of the cyclic Mn-Fe Hotazel Formation were studied at a high resolution (sampled at approximately one-meter interval). Such high-resolution approach is being employed for the first time in this project, capturing in detail the three manganese rich layers intercalated with BIF and the transitions between these lithofacies. The micro-banded BIF is made up of three major phases, namely Fe-Ca-Mg carbonates (ankerite, siderite and calcite), magnetite, and silicates (chert and minor Fe-silicates); laminated transitional lutite consist of mainly hematite, chert and Mn-carbonates, whereas the manganese ore layers are made up of mostly calcic carbonates (Mn-calcite and Ca-kutnahorite) in the form of laminations and ovoids, while Mn-silicates include dominant braunite and lesser friedelite. All three lithofacies are very fine grained (sub-mm scale) and so petrographic and mineralogical observations were obtained mostly through scanning electron microscope analysis for detailed textural relationships with focus on the carbonate fraction. Bulk geochemical studies of the entire stratigraphy of the Hotazel Formation have previously provided great insights into the cyclic nature of the deposit but have not adequately considered the potential of the carbonate fraction of the rocks as a valuable proxy for understanding the chemistry of the primary depositional environment and insights into the redox processes that were at play. This is because these carbonates have always been attributed to diagenetic processes below the sediment-water interface such as microbially-mediated dissimilatory iron/manganese reduction (DIR/DMR) where the precursor/primary Fe-Mn oxyhydroxides have been reduced to result in the minerals observed today. The carbonate fraction of the BIF is made up of ankerite and siderite which co-exist in a chert matrix as anhedral to subhedral grains with no apparent replacement textures. This suggests co-precipitation of the two species which is at apparent odds with classic diagenetic models. Similarly, Mn-carbonates in the hematite lutite and manganese ore (Mn-calcite, kutnahorite, and minor rhodocrosite) co-exist in laminae and ovoids with no textures observed that would suggest an obvious sequential mode of formation during diagenesis. In this light, a carbonate-specific geochemical analysis based on the sequential Fe extraction technique of Poulton and Canfield (2005) was employed to decipher further the cyclic nature of the Hotazel Formation and its primary versus diagenetic controls. Results from the carbonate fraction analysis of the three lithofacies show a clear fractionation of iron and manganese during primary – rather than diagenetic - carbonate precipitation, suggesting a decoupling between DIR and DMR which is ultimately interpreted to have taken place in the water column. Bulk-rock concentration results for minor and trace elements such as Zr, Ti, Sc and Al have been used for the determination of either siliciclastic or volcanic detrital inputs as they are generally immobile in most natural aqueous solutions. These elements are in very low concentrations in all three lithofacies suggesting that the depositional environment had vanishingly small contributions from terrigenous or volcanic detritus. In terms of redox-sensitive transition metals, only Mo and Co appear to show an affinity for high Mn facies in the Hotazel sequence. Cobalt in particular attains a very low abundance in the Hotazel BIF layers at an average of ~ 4 ppm. This is similar to average pre-GOE BIF in South Africa and worldwide. Maxima in Co abundance are associated with transitional hematite lutite and Mn ore layers, but maxima over 100ppm are seen in within the hematite lutite and not within the Mn ore proper where maxima in Mn are recorded. This suggests a clear and direct association with the hematite fraction in the rocks, which is modally much higher in the lutites but drops substantially in the Mn layers themselves. The similarities of bulk-rock BIF and modern-day seawater REE patterns has been used as a key argument for primary controls in REE behaviour and minimal diagenetic modification. Likewise, the three lithofacies of the Hotazel Formation analysed in this study all share similar characteristics with a clear seawater signal through gentle positive slopes in the normalised abundance of LREE versus HREE. Negative Ce anomalies prevail in the entire sample set analysed, which has been interpreted before as a proxy for oxic seawater conditions. However, positive Ce anomalies that are traditionally linked to scavenging and deposition of primary tetravalent Mn oxyhydroxides (e.g., as observed in modern day ferromanganese nodules) are completely absent from the current dataset. The lack of a positive Ce anomaly in the manganese ore and peak Co association with ferric oxides and not with peak Mn, suggests that primary deposition must have occurred within an environment that was not fully oxidizing with respect to manganese. The use of stable isotopes (i.e., C and Fe) was employed to gain insights into redox processes, whether these are thought to have happened below the sediment-water interface or in contemporaneous seawater. At a small scale, all lithofacies of the Hotazel Formation record bulk-rock δ¹³C values that are low and essentially invariant about the average value of -9.5 per mil. This is independent of sharp variations in overall modal mineralogy, relative carbonate abundance and carbonate chemistry, which is clearly difficult to reconcile with in-situ diagenetic processes that predict highly variable δ¹³C signals in response to complex combinations of precursor sediment mineralogy, pore-fluid chemistry, organic carbon supply and open vs closed system diagenesis. At a stratigraphic scale, the carbonate δ¹³C (-5 to -13‰) variations between the different lithologies could instead represent temporal changes in water-column chemistry against well-developed physico-chemical gradients, depth of deposition and biological processes. The low iron isotope values recorded in the hematite lutite and manganese ore samples can be attributed to fractionation effects of initial oxidation of ferrous iron to form Fe-oxyhydroxides in the shallow parts of the basin, from an already isotopically highly depleted aqueous Fe-pool as proposed previously. The slightly higher but still negative bulk-rock δ⁵⁶Fe values of the host BIF can be attributed to water-column Fe isotopic effects at deeper levels between primary Fe oxyhydroxides and an isotopically heavier Fe(II) pool, which was subsequently preserved during diagenetic recrystallization. All above findings were combined into a conceptual model of deposition for the three different lithologies of the Hotazel Formation. The model predicts that free molecular oxygen must have been present within the shallow oceanic environment and implicates both Mn and Fe as active redox “players” compared to classic models that apply to the origin of worldwide BIF prior to the GOE. The deposition of the Hotazel strata is interpreted to have occurred through the following three stages: (1) BIF deposition occurred in a relatively deep oceanic environment above the Ongeluk lavas during marine transgression, where a redoxcline and seawater stratification separated hydrothermally sourced iron and manganese, in response to an active Mn-shuttle mechanism linked to Mn redox cycling. Abundant ferrous iron must have been oxidized by available oxygen but also by oxidised Mn species (MnOOH) and possibly even some soluble Mn(III) complexes. Through this process, Mn(III) was being effectively reduced back into solution along with cobalt(III), as Mn(II) and Co(II) respectively, thus creating maxima in their concentrations. A drawdown of Fe(OH)₃ particles was therefore the only net precipitation mechanism at this stage. Carbonate species of Fe and the abundant magnetite would possibly have formed by reaction between the ferric hydroxides and the deeper Fe(II) pool, while organic matter would also have reacted in the water-column via DIR, accounting for the low δ¹³C signature of Fe carbonate minerals. (2) Hematite lutite formation would have occurred at a relatively shallower environment during marine regression. At this stage, reductive cycling of Fe was minimal in the absence of a deeper Fe(II) reservoir reacting with the ferric primary precipitates. Therefore, DIR progressively gave way to manganese reduction and organic carbon oxidation (DMR), which reduced MnOOH to form Mn(II)-rich carbonates in the form of kutnahorite and Mn-calcite. Co-bearing Fe(OH)₃ would have precipitated and was ultimately preserved as Co-bearing hematite during diagenesis. (3) Deposition of manganese-rich sediment occurred at even shallower oceanic depths (maximum regression) where aerobic organic carbon oxidation replaced DMR, resulting in Ca-rich carbonates such as Mn-bearing calcite and Ca-kutnahorite, yet with a low carbon isotope signature recording aerobic conditions of organic carbon cycling. Mn(III) reduction at this stage was curtailed, leading to massive precipitation of MnOOH which was diagenetically transformed into braunite and friedelite. Simultaneous precipitation of Co-bearing Fe(OH)₃ would have continued but at much more subdued rates. Repeated transgressive-regressive cycles resulted in the cyclic BIF-hematite lutite- manganese ore nature of the Hotazel Formation in an oxidized oceanic environment at the onset of the Great Oxidation Event, which was nonetheless never oxic enough to drive Mn(II) oxidation fully to its tetravalent state. The mineralogy and species-specific geochemistry of the Hotazel strata, and more specifically the carbonate fraction thereof, appear to faithfully capture the chemistry of the primary depositional environment in a progressively evolving Earth System. This project opens the door for more studies focusing on better constraining primary versus diagenetic depositional 2020 Hotazel Fe and Mn deposition mechanisms of iron and manganese during the period leading up to the GOE, and possibly re-defining the significance of Fe and Mn as invaluable redox proxies in a rapidly changing planet.
- Full Text:
- Date Issued: 2020
- Authors: Mhlanga, Xolane Reginald
- Date: 2020
- Subjects: Manganese ores -- South Africa -- Hotazel , Manganese ores -- Geology , Iron ores -- South Africa -- Hotazel , Iron ores -- Geology , Geochemistry -- South Africa -- Hotazel , Isotope geology -- South Africa -- Hotazel , Geology, Stratigraphic -- Archaean , Geology, Stratigraphic -- Proterozoic , Transvaal Supergroup (South Africa) , Great Oxidation Event
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146123 , vital:38497
- Description: Marine chemical sediments such as Banded Iron Formations deposited during the Archean-Palaeoproterozoic are studied extensively because they represent a period in the development of the Earth’s early history where the atmospheric O₂ content was below the present levels (PAL) of 21%. Prior to the Great Oxidation Event (GOE) at ca. 2.4 Ga, highly ferruginous and anoxic marine environments were dominated by extensive BIF deposition such as that of the Griqualand West Basin of the Transvaal Supergroup in South Africa. This basin is also thought to record the transition into the first rise of atmospheric O₂ in our planet, from the Koegas Subgroup to the Hotazel Formation dated at ca. 2.43 Ga (Gumsley et al., 2017). Two drill cores from the north eastern part of the Kalahari Manganese Field characterized by a well-preserved and complete intersection of the cyclic Mn-Fe Hotazel Formation were studied at a high resolution (sampled at approximately one-meter interval). Such high-resolution approach is being employed for the first time in this project, capturing in detail the three manganese rich layers intercalated with BIF and the transitions between these lithofacies. The micro-banded BIF is made up of three major phases, namely Fe-Ca-Mg carbonates (ankerite, siderite and calcite), magnetite, and silicates (chert and minor Fe-silicates); laminated transitional lutite consist of mainly hematite, chert and Mn-carbonates, whereas the manganese ore layers are made up of mostly calcic carbonates (Mn-calcite and Ca-kutnahorite) in the form of laminations and ovoids, while Mn-silicates include dominant braunite and lesser friedelite. All three lithofacies are very fine grained (sub-mm scale) and so petrographic and mineralogical observations were obtained mostly through scanning electron microscope analysis for detailed textural relationships with focus on the carbonate fraction. Bulk geochemical studies of the entire stratigraphy of the Hotazel Formation have previously provided great insights into the cyclic nature of the deposit but have not adequately considered the potential of the carbonate fraction of the rocks as a valuable proxy for understanding the chemistry of the primary depositional environment and insights into the redox processes that were at play. This is because these carbonates have always been attributed to diagenetic processes below the sediment-water interface such as microbially-mediated dissimilatory iron/manganese reduction (DIR/DMR) where the precursor/primary Fe-Mn oxyhydroxides have been reduced to result in the minerals observed today. The carbonate fraction of the BIF is made up of ankerite and siderite which co-exist in a chert matrix as anhedral to subhedral grains with no apparent replacement textures. This suggests co-precipitation of the two species which is at apparent odds with classic diagenetic models. Similarly, Mn-carbonates in the hematite lutite and manganese ore (Mn-calcite, kutnahorite, and minor rhodocrosite) co-exist in laminae and ovoids with no textures observed that would suggest an obvious sequential mode of formation during diagenesis. In this light, a carbonate-specific geochemical analysis based on the sequential Fe extraction technique of Poulton and Canfield (2005) was employed to decipher further the cyclic nature of the Hotazel Formation and its primary versus diagenetic controls. Results from the carbonate fraction analysis of the three lithofacies show a clear fractionation of iron and manganese during primary – rather than diagenetic - carbonate precipitation, suggesting a decoupling between DIR and DMR which is ultimately interpreted to have taken place in the water column. Bulk-rock concentration results for minor and trace elements such as Zr, Ti, Sc and Al have been used for the determination of either siliciclastic or volcanic detrital inputs as they are generally immobile in most natural aqueous solutions. These elements are in very low concentrations in all three lithofacies suggesting that the depositional environment had vanishingly small contributions from terrigenous or volcanic detritus. In terms of redox-sensitive transition metals, only Mo and Co appear to show an affinity for high Mn facies in the Hotazel sequence. Cobalt in particular attains a very low abundance in the Hotazel BIF layers at an average of ~ 4 ppm. This is similar to average pre-GOE BIF in South Africa and worldwide. Maxima in Co abundance are associated with transitional hematite lutite and Mn ore layers, but maxima over 100ppm are seen in within the hematite lutite and not within the Mn ore proper where maxima in Mn are recorded. This suggests a clear and direct association with the hematite fraction in the rocks, which is modally much higher in the lutites but drops substantially in the Mn layers themselves. The similarities of bulk-rock BIF and modern-day seawater REE patterns has been used as a key argument for primary controls in REE behaviour and minimal diagenetic modification. Likewise, the three lithofacies of the Hotazel Formation analysed in this study all share similar characteristics with a clear seawater signal through gentle positive slopes in the normalised abundance of LREE versus HREE. Negative Ce anomalies prevail in the entire sample set analysed, which has been interpreted before as a proxy for oxic seawater conditions. However, positive Ce anomalies that are traditionally linked to scavenging and deposition of primary tetravalent Mn oxyhydroxides (e.g., as observed in modern day ferromanganese nodules) are completely absent from the current dataset. The lack of a positive Ce anomaly in the manganese ore and peak Co association with ferric oxides and not with peak Mn, suggests that primary deposition must have occurred within an environment that was not fully oxidizing with respect to manganese. The use of stable isotopes (i.e., C and Fe) was employed to gain insights into redox processes, whether these are thought to have happened below the sediment-water interface or in contemporaneous seawater. At a small scale, all lithofacies of the Hotazel Formation record bulk-rock δ¹³C values that are low and essentially invariant about the average value of -9.5 per mil. This is independent of sharp variations in overall modal mineralogy, relative carbonate abundance and carbonate chemistry, which is clearly difficult to reconcile with in-situ diagenetic processes that predict highly variable δ¹³C signals in response to complex combinations of precursor sediment mineralogy, pore-fluid chemistry, organic carbon supply and open vs closed system diagenesis. At a stratigraphic scale, the carbonate δ¹³C (-5 to -13‰) variations between the different lithologies could instead represent temporal changes in water-column chemistry against well-developed physico-chemical gradients, depth of deposition and biological processes. The low iron isotope values recorded in the hematite lutite and manganese ore samples can be attributed to fractionation effects of initial oxidation of ferrous iron to form Fe-oxyhydroxides in the shallow parts of the basin, from an already isotopically highly depleted aqueous Fe-pool as proposed previously. The slightly higher but still negative bulk-rock δ⁵⁶Fe values of the host BIF can be attributed to water-column Fe isotopic effects at deeper levels between primary Fe oxyhydroxides and an isotopically heavier Fe(II) pool, which was subsequently preserved during diagenetic recrystallization. All above findings were combined into a conceptual model of deposition for the three different lithologies of the Hotazel Formation. The model predicts that free molecular oxygen must have been present within the shallow oceanic environment and implicates both Mn and Fe as active redox “players” compared to classic models that apply to the origin of worldwide BIF prior to the GOE. The deposition of the Hotazel strata is interpreted to have occurred through the following three stages: (1) BIF deposition occurred in a relatively deep oceanic environment above the Ongeluk lavas during marine transgression, where a redoxcline and seawater stratification separated hydrothermally sourced iron and manganese, in response to an active Mn-shuttle mechanism linked to Mn redox cycling. Abundant ferrous iron must have been oxidized by available oxygen but also by oxidised Mn species (MnOOH) and possibly even some soluble Mn(III) complexes. Through this process, Mn(III) was being effectively reduced back into solution along with cobalt(III), as Mn(II) and Co(II) respectively, thus creating maxima in their concentrations. A drawdown of Fe(OH)₃ particles was therefore the only net precipitation mechanism at this stage. Carbonate species of Fe and the abundant magnetite would possibly have formed by reaction between the ferric hydroxides and the deeper Fe(II) pool, while organic matter would also have reacted in the water-column via DIR, accounting for the low δ¹³C signature of Fe carbonate minerals. (2) Hematite lutite formation would have occurred at a relatively shallower environment during marine regression. At this stage, reductive cycling of Fe was minimal in the absence of a deeper Fe(II) reservoir reacting with the ferric primary precipitates. Therefore, DIR progressively gave way to manganese reduction and organic carbon oxidation (DMR), which reduced MnOOH to form Mn(II)-rich carbonates in the form of kutnahorite and Mn-calcite. Co-bearing Fe(OH)₃ would have precipitated and was ultimately preserved as Co-bearing hematite during diagenesis. (3) Deposition of manganese-rich sediment occurred at even shallower oceanic depths (maximum regression) where aerobic organic carbon oxidation replaced DMR, resulting in Ca-rich carbonates such as Mn-bearing calcite and Ca-kutnahorite, yet with a low carbon isotope signature recording aerobic conditions of organic carbon cycling. Mn(III) reduction at this stage was curtailed, leading to massive precipitation of MnOOH which was diagenetically transformed into braunite and friedelite. Simultaneous precipitation of Co-bearing Fe(OH)₃ would have continued but at much more subdued rates. Repeated transgressive-regressive cycles resulted in the cyclic BIF-hematite lutite- manganese ore nature of the Hotazel Formation in an oxidized oceanic environment at the onset of the Great Oxidation Event, which was nonetheless never oxic enough to drive Mn(II) oxidation fully to its tetravalent state. The mineralogy and species-specific geochemistry of the Hotazel strata, and more specifically the carbonate fraction thereof, appear to faithfully capture the chemistry of the primary depositional environment in a progressively evolving Earth System. This project opens the door for more studies focusing on better constraining primary versus diagenetic depositional 2020 Hotazel Fe and Mn deposition mechanisms of iron and manganese during the period leading up to the GOE, and possibly re-defining the significance of Fe and Mn as invaluable redox proxies in a rapidly changing planet.
- Full Text:
- Date Issued: 2020
A reconceptualisation of music performance anxiety
- Authors: Van Schoor, Nina
- Date: 2020
- Subjects: Performance anxiety , Music -- Performance -- Psychological aspects , Anxiety
- Language: English
- Type: text , Thesis , Masters , MMus
- Identifier: http://hdl.handle.net/10962/167631 , vital:41498
- Description: Music Performance Anxiety (MPA) refers to the potentially debilitating anxiety experienced before and/or during the public performance of music, despite adequate preparation. MPA is generally treated by means of drug therapy, cognitive behavioural therapy, psychoanalysis or various relaxation techniques. This research aims to present a different approach to dealing with MPA, based on a reconceptualisation of the concept. As a result, it attempts to unpack all three concepts inherent in the term from both a psychological and philosophical viewpoint. The study used autoethnography as a methodology, as I wished to explore my own lived experience of MPA and anxiety in general, in conjunction with that of my two participants, two other student Western Art music performers, and how our methods for confronting MPA within the performance context itself suggests a more complex understanding of performance and MPA than is reflected in the current literature. Thus the data was collected from two first-person interviews as well as a self-reflective written account. The results of the analysis were that existential anxiety is potentially a contributing factor to MPA, and that performance itself can potentially provide the very means for overcoming not only MPA, but all forms of anxiety, due to the cathartic quality of music as well as performance, especially when the liminal or interstructural, nature of performing and its ritualistic function is explored. This exploration reveals the world and self-disclosing nature of agency and Play, or the potential within experiences to resolve conflicts and reveal otherness. This requires a degree of existential courage, or an affirmative response to the unknown, which is more relational than the definition suggests. In conclusion, this study reconceptualises MPA as a potentially potent existential experience, and that the anxiety in response to it is considered as a reaction to the catharsis inherent in being an agent, rather than merely as an obstacle to be controlled.
- Full Text:
- Date Issued: 2020
- Authors: Van Schoor, Nina
- Date: 2020
- Subjects: Performance anxiety , Music -- Performance -- Psychological aspects , Anxiety
- Language: English
- Type: text , Thesis , Masters , MMus
- Identifier: http://hdl.handle.net/10962/167631 , vital:41498
- Description: Music Performance Anxiety (MPA) refers to the potentially debilitating anxiety experienced before and/or during the public performance of music, despite adequate preparation. MPA is generally treated by means of drug therapy, cognitive behavioural therapy, psychoanalysis or various relaxation techniques. This research aims to present a different approach to dealing with MPA, based on a reconceptualisation of the concept. As a result, it attempts to unpack all three concepts inherent in the term from both a psychological and philosophical viewpoint. The study used autoethnography as a methodology, as I wished to explore my own lived experience of MPA and anxiety in general, in conjunction with that of my two participants, two other student Western Art music performers, and how our methods for confronting MPA within the performance context itself suggests a more complex understanding of performance and MPA than is reflected in the current literature. Thus the data was collected from two first-person interviews as well as a self-reflective written account. The results of the analysis were that existential anxiety is potentially a contributing factor to MPA, and that performance itself can potentially provide the very means for overcoming not only MPA, but all forms of anxiety, due to the cathartic quality of music as well as performance, especially when the liminal or interstructural, nature of performing and its ritualistic function is explored. This exploration reveals the world and self-disclosing nature of agency and Play, or the potential within experiences to resolve conflicts and reveal otherness. This requires a degree of existential courage, or an affirmative response to the unknown, which is more relational than the definition suggests. In conclusion, this study reconceptualises MPA as a potentially potent existential experience, and that the anxiety in response to it is considered as a reaction to the catharsis inherent in being an agent, rather than merely as an obstacle to be controlled.
- Full Text:
- Date Issued: 2020