Capital or critique?: when journalism education seeks to influence the field
- Boshoff, Priscilla A, Garman, Anthea
- Authors: Boshoff, Priscilla A , Garman, Anthea
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143392 , vital:38242 , DOI: 10.1080/02560046.2016.1262437
- Description: Drawing on Bourdieu’s theories of field and capital, we examine the limitations that a journalism school at a prestigious university faces in making a meaningful contribution to the field within a developing country. In the postapartheid South African media landscape, journalism is under pressure both from global forces and a political imperative to address social justice. Given the heterogeneity of the journalistic field and the fact that what counts as capital in it is contested, the School of Journalism and Media Studies at Rhodes University attempts to redefine the parameters by inculcating a particular approach to and philosophy of journalism practice. While Rhodes wants to educate excellent (professional) journalists, it is guided by an overt political mission to cultivate a journalism that is not necessarily ‘in sync’ with the wider field. Ironically, most undergraduates come from the economic and cultural elite, with specific intentions to accumulate the capital which Rhodes bestows. Students are confronted with their privilege and with alternative ideas about the purpose of journalism, and are asked to make choices and take up positions. We consider whether this critical praxis approach is able to influence the ‘state of play’ – or the distribution of power – within the field.
- Full Text:
- Authors: Boshoff, Priscilla A , Garman, Anthea
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143392 , vital:38242 , DOI: 10.1080/02560046.2016.1262437
- Description: Drawing on Bourdieu’s theories of field and capital, we examine the limitations that a journalism school at a prestigious university faces in making a meaningful contribution to the field within a developing country. In the postapartheid South African media landscape, journalism is under pressure both from global forces and a political imperative to address social justice. Given the heterogeneity of the journalistic field and the fact that what counts as capital in it is contested, the School of Journalism and Media Studies at Rhodes University attempts to redefine the parameters by inculcating a particular approach to and philosophy of journalism practice. While Rhodes wants to educate excellent (professional) journalists, it is guided by an overt political mission to cultivate a journalism that is not necessarily ‘in sync’ with the wider field. Ironically, most undergraduates come from the economic and cultural elite, with specific intentions to accumulate the capital which Rhodes bestows. Students are confronted with their privilege and with alternative ideas about the purpose of journalism, and are asked to make choices and take up positions. We consider whether this critical praxis approach is able to influence the ‘state of play’ – or the distribution of power – within the field.
- Full Text:
Counting on demographic equity to transform institutional cultures at historically white South African universities?:
- Booi, Masixole, Vincent, Louise, Liccardo, Sabrina
- Authors: Booi, Masixole , Vincent, Louise , Liccardo, Sabrina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141946 , vital:38018 , DOI: 10.1080/07294360.2017.1289155
- Description: The post-apartheid higher education transformation project is faced with the challenge of recruiting and retaining black academics and other senior staff. But when we shift the focus from participation rates to equality–inequality within historically white universities (HWUs), then the discourse changes from demographic equity and redress to institutional culture and diversity. HWUs invoke the need to maintain their position as leading higher education institutions globally, and notions of ‘quality’ and ‘excellence’ have emerged as discursive practices, which serve to perpetuate exclusion. The question then arises as to which forms of capital comprise the Gold Standard at HWUs? Several South African universities have responded to the challenge of recruiting and retaining black academics by initiating programmes for the ‘accelerated development’ of these candidates.
- Full Text:
- Authors: Booi, Masixole , Vincent, Louise , Liccardo, Sabrina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141946 , vital:38018 , DOI: 10.1080/07294360.2017.1289155
- Description: The post-apartheid higher education transformation project is faced with the challenge of recruiting and retaining black academics and other senior staff. But when we shift the focus from participation rates to equality–inequality within historically white universities (HWUs), then the discourse changes from demographic equity and redress to institutional culture and diversity. HWUs invoke the need to maintain their position as leading higher education institutions globally, and notions of ‘quality’ and ‘excellence’ have emerged as discursive practices, which serve to perpetuate exclusion. The question then arises as to which forms of capital comprise the Gold Standard at HWUs? Several South African universities have responded to the challenge of recruiting and retaining black academics by initiating programmes for the ‘accelerated development’ of these candidates.
- Full Text:
Environmental and social recovery asymmetries to large-scale disturbances in small island communities
- Aswani, Shankar, Van Putten, Ingrid, Miñarro, Sara
- Authors: Aswani, Shankar , Van Putten, Ingrid , Miñarro, Sara
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67325 , vital:29073 , https://doi.org/10.1007/s11069-016-2685-2
- Description: publisher version , People’s livelihoods in tropical small-island developing states are greatly dependent on marine ecosystem services. Yet services such as fisheries and coastal buffering are being degraded at an alarming rate, thus making people increasing vulnerable to protracted and sudden environmental changes. In the context of the occurrences of extreme events such as earthquakes and tsunamis, it is vital to uncover the processes that make people in these island states resilient, or not, to environmental disruptions. This paper compares people’s perceptions of social and environmental impacts after an extreme event in the Western Solomon Islands (11 different villages on 8 different islands) to better understand how knowledge systems influence the coupling of human and natural systems. We examine the factors that contributed to perceptions of respective recovery in the environmental versus the social domains across communities with different traditional governance and modernization characteristics in a tsunami impact gradient. First, we separately assessed, at the community and individual level, the potential determinants of perceived recovery in the environmental and social domains. At the community level, the average values of the perceived environmental and social recovery were calculated for each community (1 year after the tsunami), and at the individual level, normally distributed environmental and social recovery variables (based on the difference in perceptions immediately and 1 year after the tsunami) were used as dependent variables in two General Linear Models. Results suggest that environmental and social resilience are not always coupled correspondingly and, less unexpectedly, that asymmetries during recovery can occur as a result of the underlying social and ecological context and existing adaptive capacity. More generally, the study shows how by evaluating post-disturbance perceptional data in tsunami-affected communities, we can better understand how subjective perceptions of change can affect the (de)-coupling of human and natural systems.
- Full Text: false
- Authors: Aswani, Shankar , Van Putten, Ingrid , Miñarro, Sara
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67325 , vital:29073 , https://doi.org/10.1007/s11069-016-2685-2
- Description: publisher version , People’s livelihoods in tropical small-island developing states are greatly dependent on marine ecosystem services. Yet services such as fisheries and coastal buffering are being degraded at an alarming rate, thus making people increasing vulnerable to protracted and sudden environmental changes. In the context of the occurrences of extreme events such as earthquakes and tsunamis, it is vital to uncover the processes that make people in these island states resilient, or not, to environmental disruptions. This paper compares people’s perceptions of social and environmental impacts after an extreme event in the Western Solomon Islands (11 different villages on 8 different islands) to better understand how knowledge systems influence the coupling of human and natural systems. We examine the factors that contributed to perceptions of respective recovery in the environmental versus the social domains across communities with different traditional governance and modernization characteristics in a tsunami impact gradient. First, we separately assessed, at the community and individual level, the potential determinants of perceived recovery in the environmental and social domains. At the community level, the average values of the perceived environmental and social recovery were calculated for each community (1 year after the tsunami), and at the individual level, normally distributed environmental and social recovery variables (based on the difference in perceptions immediately and 1 year after the tsunami) were used as dependent variables in two General Linear Models. Results suggest that environmental and social resilience are not always coupled correspondingly and, less unexpectedly, that asymmetries during recovery can occur as a result of the underlying social and ecological context and existing adaptive capacity. More generally, the study shows how by evaluating post-disturbance perceptional data in tsunami-affected communities, we can better understand how subjective perceptions of change can affect the (de)-coupling of human and natural systems.
- Full Text: false
Learning to teach in higher education in South Africa
- Council on Higher Education (South Africa), Leibowitz, Brenda, Bozalek, Vivienne, Garraway, James, Herman, Nicoline, Jawitz, Jeff, Muhuro, Patricia, Ndebele, Clever, Quinn, Lynn, Van Schalkwyk, Susan, Vorster, Jo-Anne E, Winberg, Chris
- Authors: Council on Higher Education (South Africa) , Leibowitz, Brenda , Bozalek, Vivienne , Garraway, James , Herman, Nicoline , Jawitz, Jeff , Muhuro, Patricia , Ndebele, Clever , Quinn, Lynn , Van Schalkwyk, Susan , Vorster, Jo-Anne E , Winberg, Chris
- Date: 2017
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/66524 , vital:28958
- Description: publisher version , Preface by Prof Narend Baijnath: “Teaching and learning are never neutral. Every aspect is ideological in nature: from the admission of students, to the selection of curriculum content, to the adoption of learning materials, to the pedagogical approach, to the mode of assessment and the quality of the feedback. The form of disciplinary knowledge may vary from the more subjective and contentious to the more objective and broadly accepted, but teaching and learning remain highly political acts across all institutions, faculties and disciplines. So it is unsurprising that when a country undergoes major social change, ideological demands are placed on teaching and learning.” (HE Reviewed, CHE 2016 p.143). There are many and diverse influences on teaching and learning as a political act, from broad social movements that challenge what is taught, to the ways in which resources have historically been allocated, to the values and goals of different disciplines, and the more immediate institutional and faculty contexts in which they take place. Learning to teach in higher education in South Africa is a timely and well-researched contribution to understanding the influences of that more immediate layer, that is, of institutional contexts, on the professional learning of academics in their roles as teachers. It explores questions of whether it matters to the professional learning process whether one is teaching in a context in which resources are scarce, or whether the departmental leadership style is authoritarian, or whether an institution has a strong drive to increase research output. And if it matters, what are the implications for facilitating opportunities for academics to ‘learn to teach’ in higher education? Undertaken by a team of academic staff developers across eight institutional contexts, this research report offers a comprehensive, nuanced and theorised set of insights into the role that context plays in the ways in which academics learn to teach. Such insights can inform the development of professional learning initiatives at both the institutional and national policy levels. The report is one of the outcomes of a large-scale study carried out between 2011 and 2016, made possible by funding from the National Research Foundation. It has spawned many research articles, books and PhD studies (see Appendix One) and has thus in itself provided a vehicle for the development of further research and researchers on the subject. The team chose to work collaboratively, with all the possibilities and difficulties that that entails, as reflected on in Chapter 7. Thereby, it also offers an illuminating reflection and insights into such research methodology. While the report does not specifically set out to offer anything new or surprising about the cultural and contextual differences between institutions, it does offer a coherent interpretation of such complex and intersecting conditions examined through a single theoretical lens. Indeed, the concepts of ‘structure, culture and agency’ as developed in the work of the social realist, Margaret Archer, formed the theoretical canvas for the study. The theory allows for the analytical separation of different domains for the purposes of understanding the interplay of relations, but it also offers a hope of bringing about social transformation through exercising particular modes of reflexivity. As the report argues, quoting Archer, transforming our positions in society is possible, but “their transformation depends partly on the subjective reflexivity of primary agents in seeking to play an active part in reshaping society’s resource distribution”. The researchers may not always have found it easy to apply a single theoretical lens, but the theory based study provides a coherent representation of the differences and similarities between the institutional contexts of the eight universities, throwing into relief their different influences on professional learning, and points to pathways towards the improvement of teaching and learning in South African higher education. A major contribution of this report that is likely to influence the discourse on teaching and learning significantly, is the conceptual shift from ‘professional development’ to ‘professional learning’. As an external reviewer noted, “in the context of the decolonization debate, [this shift] has the potential to offer a more flexible continuum in which to position different learning opportunities”. It also recognises the importance of group and individual agency and the importance of informal contexts in learning to teach. 12 | Monitor 14 | Learning to Teach in Higher Education in South Africa The publication of this research report takes forward the CHE’s ongoing endeavours to improve and enhance the quality of teaching and learning in higher education. It serves to complement the more practical implementation of quality assurance in higher education, which for the CHE has largely entailed a focus on teaching and learning, whether in accreditation, audits or the Quality Enhancement Project (QEP) that began in 2014 in which one of the four focus areas that universities were asked to engage with was “enhancing academics as teachers”. Participation in the QEP over the past three years has contributed to a heightened awareness across the sector of the importance of academics developing competence in university teaching, particularly given the increased emphasis being placed on student success by both the government and higher education institutions themselves. As a result, universities are becoming more intentional in their efforts to help academics develop this competence. The release of the study is therefore timely, as not only will it add to our collective understanding of the complexities and nuances in the interrelationships between structure, culture and agency that inform and influence academics in their roles as teachers, but it will serve as a useful resource for institutions in their efforts to enhance university teachers and teaching. The Higher Education Monitor series, as was elaborated in the first issue in 2003, “aims to stimulate research and the production of knowledge and interpretive frameworks that could contribute to better theorisation of higher education, more rigorous analysis of higher education complexities and more effective strategies for change and progress”. It is our hope that this report will do exactly that. , We thank the National Research Foundation for funding the project that made the study and the ensuing report possible, Professor Brenda Leibowitz for leading the team of researchers, our external reviewers, and the individual authors who took the time to present drafts of their chapters to Dr Webbstock of the CHE at a workshop in May 2016.
- Full Text:
- Authors: Council on Higher Education (South Africa) , Leibowitz, Brenda , Bozalek, Vivienne , Garraway, James , Herman, Nicoline , Jawitz, Jeff , Muhuro, Patricia , Ndebele, Clever , Quinn, Lynn , Van Schalkwyk, Susan , Vorster, Jo-Anne E , Winberg, Chris
- Date: 2017
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/66524 , vital:28958
- Description: publisher version , Preface by Prof Narend Baijnath: “Teaching and learning are never neutral. Every aspect is ideological in nature: from the admission of students, to the selection of curriculum content, to the adoption of learning materials, to the pedagogical approach, to the mode of assessment and the quality of the feedback. The form of disciplinary knowledge may vary from the more subjective and contentious to the more objective and broadly accepted, but teaching and learning remain highly political acts across all institutions, faculties and disciplines. So it is unsurprising that when a country undergoes major social change, ideological demands are placed on teaching and learning.” (HE Reviewed, CHE 2016 p.143). There are many and diverse influences on teaching and learning as a political act, from broad social movements that challenge what is taught, to the ways in which resources have historically been allocated, to the values and goals of different disciplines, and the more immediate institutional and faculty contexts in which they take place. Learning to teach in higher education in South Africa is a timely and well-researched contribution to understanding the influences of that more immediate layer, that is, of institutional contexts, on the professional learning of academics in their roles as teachers. It explores questions of whether it matters to the professional learning process whether one is teaching in a context in which resources are scarce, or whether the departmental leadership style is authoritarian, or whether an institution has a strong drive to increase research output. And if it matters, what are the implications for facilitating opportunities for academics to ‘learn to teach’ in higher education? Undertaken by a team of academic staff developers across eight institutional contexts, this research report offers a comprehensive, nuanced and theorised set of insights into the role that context plays in the ways in which academics learn to teach. Such insights can inform the development of professional learning initiatives at both the institutional and national policy levels. The report is one of the outcomes of a large-scale study carried out between 2011 and 2016, made possible by funding from the National Research Foundation. It has spawned many research articles, books and PhD studies (see Appendix One) and has thus in itself provided a vehicle for the development of further research and researchers on the subject. The team chose to work collaboratively, with all the possibilities and difficulties that that entails, as reflected on in Chapter 7. Thereby, it also offers an illuminating reflection and insights into such research methodology. While the report does not specifically set out to offer anything new or surprising about the cultural and contextual differences between institutions, it does offer a coherent interpretation of such complex and intersecting conditions examined through a single theoretical lens. Indeed, the concepts of ‘structure, culture and agency’ as developed in the work of the social realist, Margaret Archer, formed the theoretical canvas for the study. The theory allows for the analytical separation of different domains for the purposes of understanding the interplay of relations, but it also offers a hope of bringing about social transformation through exercising particular modes of reflexivity. As the report argues, quoting Archer, transforming our positions in society is possible, but “their transformation depends partly on the subjective reflexivity of primary agents in seeking to play an active part in reshaping society’s resource distribution”. The researchers may not always have found it easy to apply a single theoretical lens, but the theory based study provides a coherent representation of the differences and similarities between the institutional contexts of the eight universities, throwing into relief their different influences on professional learning, and points to pathways towards the improvement of teaching and learning in South African higher education. A major contribution of this report that is likely to influence the discourse on teaching and learning significantly, is the conceptual shift from ‘professional development’ to ‘professional learning’. As an external reviewer noted, “in the context of the decolonization debate, [this shift] has the potential to offer a more flexible continuum in which to position different learning opportunities”. It also recognises the importance of group and individual agency and the importance of informal contexts in learning to teach. 12 | Monitor 14 | Learning to Teach in Higher Education in South Africa The publication of this research report takes forward the CHE’s ongoing endeavours to improve and enhance the quality of teaching and learning in higher education. It serves to complement the more practical implementation of quality assurance in higher education, which for the CHE has largely entailed a focus on teaching and learning, whether in accreditation, audits or the Quality Enhancement Project (QEP) that began in 2014 in which one of the four focus areas that universities were asked to engage with was “enhancing academics as teachers”. Participation in the QEP over the past three years has contributed to a heightened awareness across the sector of the importance of academics developing competence in university teaching, particularly given the increased emphasis being placed on student success by both the government and higher education institutions themselves. As a result, universities are becoming more intentional in their efforts to help academics develop this competence. The release of the study is therefore timely, as not only will it add to our collective understanding of the complexities and nuances in the interrelationships between structure, culture and agency that inform and influence academics in their roles as teachers, but it will serve as a useful resource for institutions in their efforts to enhance university teachers and teaching. The Higher Education Monitor series, as was elaborated in the first issue in 2003, “aims to stimulate research and the production of knowledge and interpretive frameworks that could contribute to better theorisation of higher education, more rigorous analysis of higher education complexities and more effective strategies for change and progress”. It is our hope that this report will do exactly that. , We thank the National Research Foundation for funding the project that made the study and the ensuing report possible, Professor Brenda Leibowitz for leading the team of researchers, our external reviewers, and the individual authors who took the time to present drafts of their chapters to Dr Webbstock of the CHE at a workshop in May 2016.
- Full Text:
One size does not fit all: critical insights for effective community-based resource management in Melanesia
- Aswani, Shankar, Albert, Simon, Love, Mark
- Authors: Aswani, Shankar , Albert, Simon , Love, Mark
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145392 , vital:38434 , DOI: 10.1016/j.marpol.2017.03.041
- Description: In recent years, Fiji's approach of combining traditional systems of community-based coastal management and modern management systems has become a successful blueprint for marine conservation, particularly the Locally Managed Marine Area (LMMA) network model. As a result of this success, conservation practitioners have imported the Fiji LMMA model to the Solomon Islands and in Vanuatu in hope of replicating the purported success attained in Fiji. This paper argues that because tenure systems and associated political systems in Fiji, the Solomon Islands, and Vanuatu are substantially different, one cannot simply extrapolate the more centralized tenurial and political Fiji model to the decentralized tenurial and politically eclectic Solomons and Vanuatu. This paper provides an analysis of some of the various approaches used in these countries to make a case for why socio-political diversity and historical particulars matter to resource management and conservation-in-practice (and for any development interventions).
- Full Text:
- Authors: Aswani, Shankar , Albert, Simon , Love, Mark
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145392 , vital:38434 , DOI: 10.1016/j.marpol.2017.03.041
- Description: In recent years, Fiji's approach of combining traditional systems of community-based coastal management and modern management systems has become a successful blueprint for marine conservation, particularly the Locally Managed Marine Area (LMMA) network model. As a result of this success, conservation practitioners have imported the Fiji LMMA model to the Solomon Islands and in Vanuatu in hope of replicating the purported success attained in Fiji. This paper argues that because tenure systems and associated political systems in Fiji, the Solomon Islands, and Vanuatu are substantially different, one cannot simply extrapolate the more centralized tenurial and political Fiji model to the decentralized tenurial and politically eclectic Solomons and Vanuatu. This paper provides an analysis of some of the various approaches used in these countries to make a case for why socio-political diversity and historical particulars matter to resource management and conservation-in-practice (and for any development interventions).
- Full Text:
The influence of dose on the kinetic parameters and dosimetric features of the main thermoluminescence glow peak in α-Al2O3: C, Mg
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119834 , vital:34787 , https://doi.org/10.1016/j.nimb.2016.12.027
- Description: The influence of dose (0.1–100 Gy) on the kinetic parameters and the dosimetric features of the main glow peak of α-Al2O3:C,Mg have been investigated. Thermoluminescence (TL) measured at 1 °C/s shows a very high intensity glow peak at 161 °C and six secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. Analysis shows that the main peak follows first order kinetics irrespective of the irradiation dose. The activation energy is found to be consistent at 1.37 eV and the frequency factor is of the order of 1014 s−1 for any dose between 0.1 and 100 Gy. Further, the analysis for thermal quenching of the main peak of 0.1 Gy irradiated sample shows that the activation energy for thermal quenching is (0.94 ± 0.04) eV.
- Full Text: false
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119834 , vital:34787 , https://doi.org/10.1016/j.nimb.2016.12.027
- Description: The influence of dose (0.1–100 Gy) on the kinetic parameters and the dosimetric features of the main glow peak of α-Al2O3:C,Mg have been investigated. Thermoluminescence (TL) measured at 1 °C/s shows a very high intensity glow peak at 161 °C and six secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. Analysis shows that the main peak follows first order kinetics irrespective of the irradiation dose. The activation energy is found to be consistent at 1.37 eV and the frequency factor is of the order of 1014 s−1 for any dose between 0.1 and 100 Gy. Further, the analysis for thermal quenching of the main peak of 0.1 Gy irradiated sample shows that the activation energy for thermal quenching is (0.94 ± 0.04) eV.
- Full Text: false
Tracks and Traces: Andrew Tshabangu’s ‘Footprints’
- Authors: Lila, Philiswa
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147138 , vital:38596 , https://artthrob.co.za/2017/03/08/tracks-and-traces-andrew-tshabangus-footprints/
- Description: Andrew Tshabangu ‘Footprints’ at the Standard Bank Art Gallery is a hand-picked collection of photographs that span the past 20 years of Tshabangu’s career. Curated by Thembinkosi Goniwe, the narrative is uncomplicated and uncluttered, thus allowing the images breathing space for engagement. The display is precise with careful attention to detail, appearing neat, slick and efficient; a characteristic mirrored in Tshabangu’s photography.
- Full Text:
- Authors: Lila, Philiswa
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147138 , vital:38596 , https://artthrob.co.za/2017/03/08/tracks-and-traces-andrew-tshabangus-footprints/
- Description: Andrew Tshabangu ‘Footprints’ at the Standard Bank Art Gallery is a hand-picked collection of photographs that span the past 20 years of Tshabangu’s career. Curated by Thembinkosi Goniwe, the narrative is uncomplicated and uncluttered, thus allowing the images breathing space for engagement. The display is precise with careful attention to detail, appearing neat, slick and efficient; a characteristic mirrored in Tshabangu’s photography.
- Full Text:
Unexpected transformations of 3-(bromoacetyl)coumarin provides new evidence for the mechanism of thiol mediated dehalogenation of α-halocarbonyls
- Magwenzi, Faith N, Khanye, Setshaba D, Veale, Clinton G L
- Authors: Magwenzi, Faith N , Khanye, Setshaba D , Veale, Clinton G L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66200 , vital:28916 , https://doi.org/10.1016/j.tetlet.2017.01.082
- Description: publisher version , The mechanism for the thiol mediated dehalogenation of α-halogenated carbonyls has remained an unresolved problem, despite its ongoing application in synthetic organic chemistry. Nakamura and co-workers first proposed that net dehalogenation occurs via sequential nucleophilic substitutions, while Israel and co-workers concluded that the rate at which dehalogenation occurred suggested that dehalogenation proceeds in a single concerted step. In this study, we investigated the debromination and nucleophilic substitution of 3-(bromoacetyl)coumarin with a variety of thiophenols, whose electron donating or withdrawing natures resulted in large variations in the degree of nucleophilic substitution and dehalogenation products, respectively. Results from these experiments, in addition to an unexpected formation of thioether containing dibenzo[b,d]pyran-6-ones from a Robinson annulation, has provided new evidence for this disputed mechanism.
- Full Text: false
- Authors: Magwenzi, Faith N , Khanye, Setshaba D , Veale, Clinton G L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66200 , vital:28916 , https://doi.org/10.1016/j.tetlet.2017.01.082
- Description: publisher version , The mechanism for the thiol mediated dehalogenation of α-halogenated carbonyls has remained an unresolved problem, despite its ongoing application in synthetic organic chemistry. Nakamura and co-workers first proposed that net dehalogenation occurs via sequential nucleophilic substitutions, while Israel and co-workers concluded that the rate at which dehalogenation occurred suggested that dehalogenation proceeds in a single concerted step. In this study, we investigated the debromination and nucleophilic substitution of 3-(bromoacetyl)coumarin with a variety of thiophenols, whose electron donating or withdrawing natures resulted in large variations in the degree of nucleophilic substitution and dehalogenation products, respectively. Results from these experiments, in addition to an unexpected formation of thioether containing dibenzo[b,d]pyran-6-ones from a Robinson annulation, has provided new evidence for this disputed mechanism.
- Full Text: false
Russian wheat aphids: Breakfast, lunch, and supper. Feasting on small grains in South Africa
- Botha, Christiaan E J, Sacranie, S, Gallagher, Sean, Hill, Jaclyn M
- Authors: Botha, Christiaan E J , Sacranie, S , Gallagher, Sean , Hill, Jaclyn M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69031 , vital:29374 , https://doi.org/10.1016/j.sajb.2016.12.006
- Description: The Russian Wheat Aphid (Diuraphis noxia, RWA) negatively impacts commercially grown barley and wheat in South Africa. Climate change, the attendant rise in [CO2], and the appearance of new RWA biotypes have the potential to induce severe crop yield loss in agriculturally important wheat and barley cultivars. This study presents data showing changes in relative aphid population numbers, concurrently with assessments of plant damage under controlled environmental conditions, under ambient and elevated (450 ppm) [CO2]. Extensive structural damage to the vascular tissue and disruption to the transport systems were revealed using light, fluorescence and electron microscopy. This, coupled with biotype population studies, demonstrated that RWA has the capacity to inflict severe, potentially permanent damage to vegetative small grain plants. Furthermore, some currently ‘resistant’ cultivars may well lose resistance as a direct result of increasing atmospheric [CO2]. A small (50 ppm) increase in atmospheric [CO2] may result in increased aphid population numbers, potentially serious plant damage and, by implication, a potentially negative impact on yield, as increased aphid density per plant leads to an accelerated disruption of the assimilate and transpiration transport pathways. These outcomes pose a direct threat to the commercial small grain industry of South Africa and by extension, to other small grain production areas elsewhere.
- Full Text: false
- Authors: Botha, Christiaan E J , Sacranie, S , Gallagher, Sean , Hill, Jaclyn M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69031 , vital:29374 , https://doi.org/10.1016/j.sajb.2016.12.006
- Description: The Russian Wheat Aphid (Diuraphis noxia, RWA) negatively impacts commercially grown barley and wheat in South Africa. Climate change, the attendant rise in [CO2], and the appearance of new RWA biotypes have the potential to induce severe crop yield loss in agriculturally important wheat and barley cultivars. This study presents data showing changes in relative aphid population numbers, concurrently with assessments of plant damage under controlled environmental conditions, under ambient and elevated (450 ppm) [CO2]. Extensive structural damage to the vascular tissue and disruption to the transport systems were revealed using light, fluorescence and electron microscopy. This, coupled with biotype population studies, demonstrated that RWA has the capacity to inflict severe, potentially permanent damage to vegetative small grain plants. Furthermore, some currently ‘resistant’ cultivars may well lose resistance as a direct result of increasing atmospheric [CO2]. A small (50 ppm) increase in atmospheric [CO2] may result in increased aphid population numbers, potentially serious plant damage and, by implication, a potentially negative impact on yield, as increased aphid density per plant leads to an accelerated disruption of the assimilate and transpiration transport pathways. These outcomes pose a direct threat to the commercial small grain industry of South Africa and by extension, to other small grain production areas elsewhere.
- Full Text: false
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