Reflections on Teaching Africa in South Africa:
- Authors: Matthews, Sally
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142235 , vital:38061 , DOI: 10.1111/1467-9256.12107
- Description: This article draws on the author’s experience of teaching African Studies to undergraduate South African students in order to reflect on some of the key challenges facing teachers of African Studies, both in South Africa and beyond. In particular, it discusses challenges relating to teaching a field as contested as African Studies, looking at whether teaching African alternatives to mainstream African politics is helpful and at whether and how one can teach Africa in a way that encourages and develops critical thinking. The article also explores how the racial politics of the context in which one teaches African Studies inevitably affects the way in which students engage with the content of the course. While the article discusses these issues in relation to the South African higher education context in particular, implications for other contexts are also highlighted.
- Full Text:
- Date Issued: 2016
- Authors: Matthews, Sally
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142235 , vital:38061 , DOI: 10.1111/1467-9256.12107
- Description: This article draws on the author’s experience of teaching African Studies to undergraduate South African students in order to reflect on some of the key challenges facing teachers of African Studies, both in South Africa and beyond. In particular, it discusses challenges relating to teaching a field as contested as African Studies, looking at whether teaching African alternatives to mainstream African politics is helpful and at whether and how one can teach Africa in a way that encourages and develops critical thinking. The article also explores how the racial politics of the context in which one teaches African Studies inevitably affects the way in which students engage with the content of the course. While the article discusses these issues in relation to the South African higher education context in particular, implications for other contexts are also highlighted.
- Full Text:
- Date Issued: 2016
The influence of photoperiod on the reproductive physiology of the greater red musk shrew: Crocidura flavescens
- Hoole, C, McKechnie, Andrew E, Parker, Daniel M, Bennett, Nigel C
- Authors: Hoole, C , McKechnie, Andrew E , Parker, Daniel M , Bennett, Nigel C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70136 , vital:29624 , https://doi.org/10.1139/cjz-2015-0128
- Description: Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and eminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator. Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success.
- Full Text: false
- Date Issued: 2016
- Authors: Hoole, C , McKechnie, Andrew E , Parker, Daniel M , Bennett, Nigel C
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70136 , vital:29624 , https://doi.org/10.1139/cjz-2015-0128
- Description: Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and eminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator. Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success.
- Full Text: false
- Date Issued: 2016
A River of Blood Flows: Lerato Shadi’s ‘Noka Ya Bokamoso’
- Authors: Makandula, Sikhumbuzo
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147258 , vital:38609 , https://artthrob.co.za/2016/07/13/a-river-of-blood-flows-lerato-shadis-noka-ya-bokamoso/
- Description: The title of Lerato Shadi’s show, ‘Noka Ya Bokamoso,’ which opened at National Arts Festival in Grahamstown, translates from Setswana to ‘a river of tomorrow.’ In the Albany gallery you encounter Shadi performing Mosako Wa Nako. She sits silently crocheting a ball of red wool into a scroll which unfurls with indecipherable writing. Shadi’s isolation from the rest of the artworks on the exhibition draws you closer, emphasising the rhythmic movement of her hands.
- Full Text:
- Date Issued: 2016
- Authors: Makandula, Sikhumbuzo
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147258 , vital:38609 , https://artthrob.co.za/2016/07/13/a-river-of-blood-flows-lerato-shadis-noka-ya-bokamoso/
- Description: The title of Lerato Shadi’s show, ‘Noka Ya Bokamoso,’ which opened at National Arts Festival in Grahamstown, translates from Setswana to ‘a river of tomorrow.’ In the Albany gallery you encounter Shadi performing Mosako Wa Nako. She sits silently crocheting a ball of red wool into a scroll which unfurls with indecipherable writing. Shadi’s isolation from the rest of the artworks on the exhibition draws you closer, emphasising the rhythmic movement of her hands.
- Full Text:
- Date Issued: 2016
“Turn on” fluorescence enhancement of Zn octacarboxyphthaloyanine-graphene oxide conjugates by hydrogen peroxide
- Shumba, Munyaradzi, Mashazi, Philani N, Nyokong, Tebello
- Authors: Shumba, Munyaradzi , Mashazi, Philani N , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240875 , vital:50881 , xlink:href="https://doi.org/10.1016/j.jlumin.2015.11.001"
- Description: Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates were characterized by absorption spectroscopy, transmission electron microscopy, fluorescence spectroscopy, X-ray diffraction, thermo gravimetric analysis and X-ray photon spectroscopy. The presence of reduced graphene oxide or graphene oxide resulted in the quenching (turn on) of Zn octacarboxy phthalocyanine fluorescence which can be explained by photoinduced electron transfer. Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates “turned on” fluorescence showed a linear response to hydrogen peroxide hence their potential to be used as sensors. The nanoprobe developed showed high selectivity towards hydrogen peroxide in the presence of physiological interferences.
- Full Text:
- Date Issued: 2016
- Authors: Shumba, Munyaradzi , Mashazi, Philani N , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240875 , vital:50881 , xlink:href="https://doi.org/10.1016/j.jlumin.2015.11.001"
- Description: Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates were characterized by absorption spectroscopy, transmission electron microscopy, fluorescence spectroscopy, X-ray diffraction, thermo gravimetric analysis and X-ray photon spectroscopy. The presence of reduced graphene oxide or graphene oxide resulted in the quenching (turn on) of Zn octacarboxy phthalocyanine fluorescence which can be explained by photoinduced electron transfer. Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates “turned on” fluorescence showed a linear response to hydrogen peroxide hence their potential to be used as sensors. The nanoprobe developed showed high selectivity towards hydrogen peroxide in the presence of physiological interferences.
- Full Text:
- Date Issued: 2016
“Turn on” fluorescence enhancement of Zn octacarboxyphthaloyanine-graphene oxide conjugates by hydrogen peroxide
- Shumba, Munyaradzi, Mashazi, Philani N, Nyokong, Tebello
- Authors: Shumba, Munyaradzi , Mashazi, Philani N , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190438 , vital:44994 , xlink:href="https://doi.org/10.1016/j.jlumin.2015.11.001"
- Description: Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates were characterized by absorption spectroscopy, transmission electron microscopy, fluorescence spectroscopy, X-ray diffraction, thermo gravimetric analysis and X-ray photon spectroscopy. The presence of reduced graphene oxide or graphene oxide resulted in the quenching (turn on) of Zn octacarboxy phthalocyanine fluorescence which can be explained by photoinduced electron transfer. Zn octacarboxy phthalocyaninereduced graphene oxide or graphene oxide conjugates “turned on” fluorescence showed a linear response to hydrogen peroxide hence their potential to be used as sensors. The nanoprobe developed showed high selectivity towards hydrogen peroxide in the presence of physiological interferences.
- Full Text:
- Date Issued: 2016
- Authors: Shumba, Munyaradzi , Mashazi, Philani N , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190438 , vital:44994 , xlink:href="https://doi.org/10.1016/j.jlumin.2015.11.001"
- Description: Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates were characterized by absorption spectroscopy, transmission electron microscopy, fluorescence spectroscopy, X-ray diffraction, thermo gravimetric analysis and X-ray photon spectroscopy. The presence of reduced graphene oxide or graphene oxide resulted in the quenching (turn on) of Zn octacarboxy phthalocyanine fluorescence which can be explained by photoinduced electron transfer. Zn octacarboxy phthalocyaninereduced graphene oxide or graphene oxide conjugates “turned on” fluorescence showed a linear response to hydrogen peroxide hence their potential to be used as sensors. The nanoprobe developed showed high selectivity towards hydrogen peroxide in the presence of physiological interferences.
- Full Text:
- Date Issued: 2016
Designing writing groups to support postgraduate students’ academic writing: a case study from a South African university
- Authors: Wilmot, Kirstin
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66267 , vital:28926 , https://doi.org/10.1080/14703297.2016.1238775
- Description: publisher version , This paper reports on a writing group pilot programme implemented at a South African university. Drawing on literature, anonymous student evaluations and facilitator observations, it discusses the use of writing groups for supporting postgraduate academic writing practices. Developed within a broader postgraduate academic writing support programme, the paper discusses a case study of two pilot writing groups: a multidisciplinary long-term group and a disciplinary short-term ‘writing-intensive’ group. The findings indicate that the overall experience of the writing group was a positive one, with each group presenting varied ‘success’ aspects as well as challenges. Insights gleaned may contribute to our understanding of how these groups can be utilised to support postgraduate students and how different kinds of groups can be developed to serve particular student needs. The paper concludes with a discussion of the inclusion of a disciplinary expert, which proved particularly useful in this pilot.
- Full Text: false
- Date Issued: 2018
- Authors: Wilmot, Kirstin
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66267 , vital:28926 , https://doi.org/10.1080/14703297.2016.1238775
- Description: publisher version , This paper reports on a writing group pilot programme implemented at a South African university. Drawing on literature, anonymous student evaluations and facilitator observations, it discusses the use of writing groups for supporting postgraduate academic writing practices. Developed within a broader postgraduate academic writing support programme, the paper discusses a case study of two pilot writing groups: a multidisciplinary long-term group and a disciplinary short-term ‘writing-intensive’ group. The findings indicate that the overall experience of the writing group was a positive one, with each group presenting varied ‘success’ aspects as well as challenges. Insights gleaned may contribute to our understanding of how these groups can be utilised to support postgraduate students and how different kinds of groups can be developed to serve particular student needs. The paper concludes with a discussion of the inclusion of a disciplinary expert, which proved particularly useful in this pilot.
- Full Text: false
- Date Issued: 2018
Art investment in South Africa: portfolio diversification and art market efficiency
- Botha, Ferdi, Snowball, Jeanette D, Scott, Brett
- Authors: Botha, Ferdi , Snowball, Jeanette D , Scott, Brett
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/64794 , vital:28601 , http://www.dx.doi.org/10.17159/2222-3436/2016/v19n3a4
- Description: Art has been suggested as a good way to diversify investment portfolios during times of financial uncertainty. The argument is that art exhibits different risk and return characteristics to conventional investments in other asset classes. The new Citadel art price index offered the opportunity to test this theory in the South African context. Moreover, this paper tests whether art prices are efficient. The Citadel index uses the hedonic regression method with observations drawn from the top 100, 50 and 20 artists by sales volume, giving approximately 29 503 total auction observations. The Index consists of quarterly data from the period 2000Q1 to 2013Q3. A vector autoregression of the art price index, Johannesburg stock exchange all-share index, house price index, and South African government bond index were used. Results show that, when there are increased returns on the stock market in a preceding period and wealth increases, there is a change in the Citadel art price index in the same direction. No significant difference was found between the house price index and the art price index, or between the art and government bond price indices. The art market is also found to be inefficient, thereby exacerbating the risk of investing in art. Overall, the South African art market does not offer the opportunity to diversify portfolios dominated by either property, bonds, or shares.
- Full Text:
- Date Issued: 2016
- Authors: Botha, Ferdi , Snowball, Jeanette D , Scott, Brett
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/64794 , vital:28601 , http://www.dx.doi.org/10.17159/2222-3436/2016/v19n3a4
- Description: Art has been suggested as a good way to diversify investment portfolios during times of financial uncertainty. The argument is that art exhibits different risk and return characteristics to conventional investments in other asset classes. The new Citadel art price index offered the opportunity to test this theory in the South African context. Moreover, this paper tests whether art prices are efficient. The Citadel index uses the hedonic regression method with observations drawn from the top 100, 50 and 20 artists by sales volume, giving approximately 29 503 total auction observations. The Index consists of quarterly data from the period 2000Q1 to 2013Q3. A vector autoregression of the art price index, Johannesburg stock exchange all-share index, house price index, and South African government bond index were used. Results show that, when there are increased returns on the stock market in a preceding period and wealth increases, there is a change in the Citadel art price index in the same direction. No significant difference was found between the house price index and the art price index, or between the art and government bond price indices. The art market is also found to be inefficient, thereby exacerbating the risk of investing in art. Overall, the South African art market does not offer the opportunity to diversify portfolios dominated by either property, bonds, or shares.
- Full Text:
- Date Issued: 2016
Influence of argon-implantation on conventional and phototransferred thermoluminescence of synthetic quartz
- Nsengiyumva, S, Chithambo, Makaiko L, Pichon, L
- Authors: Nsengiyumva, S , Chithambo, Makaiko L , Pichon, L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124732 , vital:35656 , DOI: 10.1080/10420150.2016.1194412
- Description: Conventional and phototransferred thermoluminescence of crystalline synthetic quartz implanted with 70 keV Ar ions at fluences in the range 1 × 1014–5 × 1015 ions/cm2 is reported. The glow curves, recorded at 5°C/s from beta-irradiated samples of similar mass, show a prominent peak between 100°C and 120°C. The thermoluminescence intensity of all implanted samples was greater than that of the unimplanted one. The increase in sensitivity is attributed to a corresponding increase in the concentration of point defects, as a result of the implantation, which act as electron traps or recombination centres. Kinetic analysis carried out using the peak shape, whole glow-peak and curve-fitting methods produced values of the activation energy, frequency factor and order of kinetics that are generally independent of implantation fluence. This result suggests that implantation did not necessarily affect the nature of the electron traps. With respect to phototransferred thermoluminescence, it was observed that it only appeared in the sample implanted at the highest fluence of 5 × 1015 ions/cm2. This may be so because the concentration of deep traps produced as a result of implantation at low fluence is too low to give rise to phototransferred thermoluminescence. The intensity of the phototransferred thermoluminescence goes through a peak with illumination time. We attribute this behaviour to the relative concentration of holes at recombination centres and phototransferred electrons at shallow traps.
- Full Text: false
- Date Issued: 2016
- Authors: Nsengiyumva, S , Chithambo, Makaiko L , Pichon, L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124732 , vital:35656 , DOI: 10.1080/10420150.2016.1194412
- Description: Conventional and phototransferred thermoluminescence of crystalline synthetic quartz implanted with 70 keV Ar ions at fluences in the range 1 × 1014–5 × 1015 ions/cm2 is reported. The glow curves, recorded at 5°C/s from beta-irradiated samples of similar mass, show a prominent peak between 100°C and 120°C. The thermoluminescence intensity of all implanted samples was greater than that of the unimplanted one. The increase in sensitivity is attributed to a corresponding increase in the concentration of point defects, as a result of the implantation, which act as electron traps or recombination centres. Kinetic analysis carried out using the peak shape, whole glow-peak and curve-fitting methods produced values of the activation energy, frequency factor and order of kinetics that are generally independent of implantation fluence. This result suggests that implantation did not necessarily affect the nature of the electron traps. With respect to phototransferred thermoluminescence, it was observed that it only appeared in the sample implanted at the highest fluence of 5 × 1015 ions/cm2. This may be so because the concentration of deep traps produced as a result of implantation at low fluence is too low to give rise to phototransferred thermoluminescence. The intensity of the phototransferred thermoluminescence goes through a peak with illumination time. We attribute this behaviour to the relative concentration of holes at recombination centres and phototransferred electrons at shallow traps.
- Full Text: false
- Date Issued: 2016
Colonised minds?: post-development theory and the desirability of development in Africa
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
- Full Text:
- Date Issued: 2017
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
- Full Text:
- Date Issued: 2017
Aggregation control of robust water-soluble zinc (II) phthalocyanine-based photosensitizers
- Ikeuchi, Takuro, Mack, John, Nyokong, Tebello, Kobayashi, Nagao, Kimura, Mutsumi
- Authors: Ikeuchi, Takuro , Mack, John , Nyokong, Tebello , Kobayashi, Nagao , Kimura, Mutsumi
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239709 , vital:50757 , xlink:href="https://doi.org/10.1021/acs.langmuir.6b03552"
- Description: A water-soluble zinc phthalocyanine (ZnPc) complex with four negatively charged electron-withdrawing sulfonic acid substituents at the nonperipheral positions (α-ZnTSPc) is found to have a high singlet oxygen (1O2) quantum yield and exhibits high photostability. The formation of aggregates is hindered and the highest occupied molecular orbital is significantly stabilized, making α-ZnTSPc potentially suitable for its use as a photosensitizer for photodynamic therapy and photoimmunotherapy. Atomic force microscopy (AFM) reveals that mixtures of the negatively charged α-ZnTSPc complex with a similar positively charged ZnPc were found to result in the self-assembly of one-dimensional accordion-like fibers. Supramolecular fibers can be formed in aqueous solutions through intermolecular electrostatic and donor–acceptor interactions between the two water-soluble ZnPcs.
- Full Text:
- Date Issued: 2016
- Authors: Ikeuchi, Takuro , Mack, John , Nyokong, Tebello , Kobayashi, Nagao , Kimura, Mutsumi
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239709 , vital:50757 , xlink:href="https://doi.org/10.1021/acs.langmuir.6b03552"
- Description: A water-soluble zinc phthalocyanine (ZnPc) complex with four negatively charged electron-withdrawing sulfonic acid substituents at the nonperipheral positions (α-ZnTSPc) is found to have a high singlet oxygen (1O2) quantum yield and exhibits high photostability. The formation of aggregates is hindered and the highest occupied molecular orbital is significantly stabilized, making α-ZnTSPc potentially suitable for its use as a photosensitizer for photodynamic therapy and photoimmunotherapy. Atomic force microscopy (AFM) reveals that mixtures of the negatively charged α-ZnTSPc complex with a similar positively charged ZnPc were found to result in the self-assembly of one-dimensional accordion-like fibers. Supramolecular fibers can be formed in aqueous solutions through intermolecular electrostatic and donor–acceptor interactions between the two water-soluble ZnPcs.
- Full Text:
- Date Issued: 2016
Preference for C4 shade grasses increases hatchling performance in the butterfly, Bicyclus safitza
- Nokelainen, Ossi, Ripley, Bradford Sherman, Van Bergen, Erik, Osborne, Colin P, Brakefield, Paul M
- Authors: Nokelainen, Ossi , Ripley, Bradford Sherman , Van Bergen, Erik , Osborne, Colin P , Brakefield, Paul M
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61424 , vital:28025 , http://onlinelibrary.wiley.com/doi/10.1002/ece3.2235/full
- Description: The Miocene radiation of C4 grasses under high-temperature and low ambient CO2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant–herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant–herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.
- Full Text:
- Date Issued: 2016
- Authors: Nokelainen, Ossi , Ripley, Bradford Sherman , Van Bergen, Erik , Osborne, Colin P , Brakefield, Paul M
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61424 , vital:28025 , http://onlinelibrary.wiley.com/doi/10.1002/ece3.2235/full
- Description: The Miocene radiation of C4 grasses under high-temperature and low ambient CO2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant–herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant–herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.
- Full Text:
- Date Issued: 2016
Interaction of graphene quantum dots with 4-acetamido-2, 2, 6, 6-tetramethylpiperidine-oxyl free radicals
- Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189031 , vital:44810 , xlink:href="https://doi.org/10.1007/s10895-015-1712-0"
- Description: We report on the interaction of graphene quantum dots (GQDs) with 4-acetamido-2,2,6,6-tetramethylpiperidineoxyl (4-acetamido-TEMPO) free radicals. The GQDs were N and S, N doped. The fluorescence quantum yields were higher for the doped GQDs compared to the undoped. The interaction is assessed by spectrofluorimetric, steady state/time resolved fluorescence and electron paramagnetic resonance (EPR) techniques. Fluorescence quenching was observed upon the addition of 4-acetamido-TEMPO to the GQDs. Photoinduced electron transfer (PET) mechanism was suggested as the plausible mechanism involved in the fluorescence quenching in which 4-acetamido-TEMPO acted as the electron acceptor.
- Full Text:
- Date Issued: 2016
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189031 , vital:44810 , xlink:href="https://doi.org/10.1007/s10895-015-1712-0"
- Description: We report on the interaction of graphene quantum dots (GQDs) with 4-acetamido-2,2,6,6-tetramethylpiperidineoxyl (4-acetamido-TEMPO) free radicals. The GQDs were N and S, N doped. The fluorescence quantum yields were higher for the doped GQDs compared to the undoped. The interaction is assessed by spectrofluorimetric, steady state/time resolved fluorescence and electron paramagnetic resonance (EPR) techniques. Fluorescence quenching was observed upon the addition of 4-acetamido-TEMPO to the GQDs. Photoinduced electron transfer (PET) mechanism was suggested as the plausible mechanism involved in the fluorescence quenching in which 4-acetamido-TEMPO acted as the electron acceptor.
- Full Text:
- Date Issued: 2016
Heterogeneity in virulence relationships between Cryptophlebia leucotreta granulovirus isolates and geographically distinct host populations: Lessons from codling moth resistance to CpGV-M
- Opoku-Debrah, John K, Hill, Martin P, Knox, Caroline M, Moore, Sean D
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417998 , vital:71500 , xlink:href="https://doi.org/10.1007/s10526-016-9728-1"
- Description: In South Africa, the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) is used to control the citrus pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). However, the risk associated with continuous application of a single active ingredient is resistance. In order to manage resistance should it occur in field populations of T. leucotreta in South Africa, five new CrleGV genotypes from geographically distinct insect populations which were shown to exhibit some degree of phenotypic variation were recovered and genetically characterized. In droplet bioassays using seven CrleGV isolates against five T. leucotreta populations, some isolates were found to show higher virulence to some host populations than others. There were marked differences in the LD50 values of isolates and the number of occlusion bodies required per larva ranged between 0.79 and 3.12. The significance of these findings with respect to the application of CrleGV biopesticides and the management of resistance is discussed.
- Full Text:
- Date Issued: 2016
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417998 , vital:71500 , xlink:href="https://doi.org/10.1007/s10526-016-9728-1"
- Description: In South Africa, the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) is used to control the citrus pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). However, the risk associated with continuous application of a single active ingredient is resistance. In order to manage resistance should it occur in field populations of T. leucotreta in South Africa, five new CrleGV genotypes from geographically distinct insect populations which were shown to exhibit some degree of phenotypic variation were recovered and genetically characterized. In droplet bioassays using seven CrleGV isolates against five T. leucotreta populations, some isolates were found to show higher virulence to some host populations than others. There were marked differences in the LD50 values of isolates and the number of occlusion bodies required per larva ranged between 0.79 and 3.12. The significance of these findings with respect to the application of CrleGV biopesticides and the management of resistance is discussed.
- Full Text:
- Date Issued: 2016
Collaborative learning of water conservation practices: cultivation and expansion of a learning network around rainwater harvesting demonstration sites in the Eastern Cape, South Africa
- Pesanayi, Tichaona V, Weaver, Kim N
- Authors: Pesanayi, Tichaona V , Weaver, Kim N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392086 , vital:68720 , xlink:href="https://www.ajol.info/index.php/sajae/article/view/138570"
- Description: Learning together in mediated voluntary networks can mobilise skills and innovations that help to facilitate learning and uptake of rainwater harvesting and conservation practices. It boosts extension capacity while at the same time growing farmer capabilities, tapping on the distributed cognition. These practices help to heal wicked problems of drought and global change challenges affecting marginalised farmers in South Africa. South Africa has water, nutrition and food security challenges, especially the Eastern Cape Province where there is a relatively high level of poverty. These challenges place heavy pressure on the agricultural sector as it is the main user of the allocated water in the country. In this paper, the learning of and agency for rainwater harvesting and conservation practices are explored as responses to these challenges. Despite existing cultural histories of such practices among the amaXhosa people, information on these practices is not readily available to small-scale rural farmers who thus struggle for the want of knowing. This research forms part of a Water Research Commission project, Amanzi for Food, whose intention is to mediate collaborative and co-engaged learning among networked farmers, extension workers, researchers and agricultural educators through course-mediated use of Water Research Commission rainwater harvesting and conservation materials.
- Full Text:
- Date Issued: 2016
- Authors: Pesanayi, Tichaona V , Weaver, Kim N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392086 , vital:68720 , xlink:href="https://www.ajol.info/index.php/sajae/article/view/138570"
- Description: Learning together in mediated voluntary networks can mobilise skills and innovations that help to facilitate learning and uptake of rainwater harvesting and conservation practices. It boosts extension capacity while at the same time growing farmer capabilities, tapping on the distributed cognition. These practices help to heal wicked problems of drought and global change challenges affecting marginalised farmers in South Africa. South Africa has water, nutrition and food security challenges, especially the Eastern Cape Province where there is a relatively high level of poverty. These challenges place heavy pressure on the agricultural sector as it is the main user of the allocated water in the country. In this paper, the learning of and agency for rainwater harvesting and conservation practices are explored as responses to these challenges. Despite existing cultural histories of such practices among the amaXhosa people, information on these practices is not readily available to small-scale rural farmers who thus struggle for the want of knowing. This research forms part of a Water Research Commission project, Amanzi for Food, whose intention is to mediate collaborative and co-engaged learning among networked farmers, extension workers, researchers and agricultural educators through course-mediated use of Water Research Commission rainwater harvesting and conservation materials.
- Full Text:
- Date Issued: 2016
Listening to the ‘Born Frees’: politics and disillusionment in South Africa
- Malila, Vanessa, Garman, Anthea
- Authors: Malila, Vanessa , Garman, Anthea
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158884 , vital:40237 , https://doi.org/10.1080/23743670.2015.1084587
- Description: In 2014 South Africa celebrated 20 years of democracy, and for many of the ‘Born Frees’ – those who came of age politically after 1996 – this was their first opportunity to vote in national elections. With democracy came the promise for South Africa's marginalised majority of voice and agency, but also the implicit promise that their democratically elected government would listen to them. In addition, the South African media have long championed their role as a voice for the voiceless. This article presents work done with youngsters from South Africa's poorest province, the Eastern Cape, in an effort to listen to their experience of politics and to understand their use of the media – especially whether it enables them to speak out and be heard in the public sphere.
- Full Text:
- Date Issued: 2016
- Authors: Malila, Vanessa , Garman, Anthea
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158884 , vital:40237 , https://doi.org/10.1080/23743670.2015.1084587
- Description: In 2014 South Africa celebrated 20 years of democracy, and for many of the ‘Born Frees’ – those who came of age politically after 1996 – this was their first opportunity to vote in national elections. With democracy came the promise for South Africa's marginalised majority of voice and agency, but also the implicit promise that their democratically elected government would listen to them. In addition, the South African media have long championed their role as a voice for the voiceless. This article presents work done with youngsters from South Africa's poorest province, the Eastern Cape, in an effort to listen to their experience of politics and to understand their use of the media – especially whether it enables them to speak out and be heard in the public sphere.
- Full Text:
- Date Issued: 2016
Encompassing the relative non-target risks from agents and their alien plant targets in biological control assessments
- Downey, Paul O, Paterson, Iain D
- Authors: Downey, Paul O , Paterson, Iain D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417940 , vital:71496 , xlink:href="https://doi.org/10.1007/s10526-016-9744-1"
- Description: Criticisms about the safety of biological control of alien plants has resulted in a risk-averse approach, where the risks posed by the agent are paramount and the risks posed by the alien plant are neglected. We argue that the risk associated with non-target damage from agents needs to be assessed relative to that of their target alien plants. A literature review of the non-target risks associated with biological control agents was undertaken in terms of the risk to native species from agents relative to the risk to native species from their alien plant targets. We then developed a framework that compares the consequence with the likelihood of non-target damage for both agents and their targets to provide an overall risk rating. Assessments of the risk of damage from both agents and their target alien plants will enable researchers, managers and policy makers to better assess the risks from biological control.
- Full Text:
- Date Issued: 2016
- Authors: Downey, Paul O , Paterson, Iain D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417940 , vital:71496 , xlink:href="https://doi.org/10.1007/s10526-016-9744-1"
- Description: Criticisms about the safety of biological control of alien plants has resulted in a risk-averse approach, where the risks posed by the agent are paramount and the risks posed by the alien plant are neglected. We argue that the risk associated with non-target damage from agents needs to be assessed relative to that of their target alien plants. A literature review of the non-target risks associated with biological control agents was undertaken in terms of the risk to native species from agents relative to the risk to native species from their alien plant targets. We then developed a framework that compares the consequence with the likelihood of non-target damage for both agents and their targets to provide an overall risk rating. Assessments of the risk of damage from both agents and their target alien plants will enable researchers, managers and policy makers to better assess the risks from biological control.
- Full Text:
- Date Issued: 2016
MARS: Motif Assessment and Ranking Suite for transcription factor binding motifs
- Kibet, Caleb K, Machanick, Philip
- Authors: Kibet, Caleb K , Machanick, Philip
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61155 , vital:27985 , http://dx.doi.org/10.1101/065615
- Description: We describe MARS (Motif Assessment and Ranking Suite), a web-based suite of tools used to evaluate and rank PWM-based motifs. The increased number of learned motif models that are spread across databases and in different PWM formats, leading to a choice dilemma among the users, is our motivation. This increase has been driven by the difficulty of modelling transcription factor binding sites and the advance in high-throughput sequencing technologies at a continually reducing cost. Therefore, several experimental techniques have been developed resulting in diverse motif-finding algorithms and databases. We collate a wide variety of available motifs into a benchmark database, including the corresponding experimental ChIP-seq and PBM data obtained from ENCODE and UniPROBE databases, respectively. The implemented tools include: a data-independent consistency-based motif assessment and ranking (CB-MAR), which is based on the idea that `correct motifs' are more similar to each other while incorrect motifs will differ from each other; and a scoring and classification-based algorithms, which rank binding models by their ability to discriminate sequences known to contain binding sites from those without. The CB-MAR and scoring techniques have a 0.86 and 0.73 median rank correlation using ChIP-seq and PBM respectively. Best motifs selected by CB-MAR achieve a mean AUC of 0.75, comparable to those ranked by held out data at 0.76 { this is based on ChIP-seq motif discovery using five algorithms on 110 transcription factors. We have demonstrated the benefit of this web server in motif choice and ranking, as well as in motif.
- Full Text:
- Date Issued: 2016
- Authors: Kibet, Caleb K , Machanick, Philip
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61155 , vital:27985 , http://dx.doi.org/10.1101/065615
- Description: We describe MARS (Motif Assessment and Ranking Suite), a web-based suite of tools used to evaluate and rank PWM-based motifs. The increased number of learned motif models that are spread across databases and in different PWM formats, leading to a choice dilemma among the users, is our motivation. This increase has been driven by the difficulty of modelling transcription factor binding sites and the advance in high-throughput sequencing technologies at a continually reducing cost. Therefore, several experimental techniques have been developed resulting in diverse motif-finding algorithms and databases. We collate a wide variety of available motifs into a benchmark database, including the corresponding experimental ChIP-seq and PBM data obtained from ENCODE and UniPROBE databases, respectively. The implemented tools include: a data-independent consistency-based motif assessment and ranking (CB-MAR), which is based on the idea that `correct motifs' are more similar to each other while incorrect motifs will differ from each other; and a scoring and classification-based algorithms, which rank binding models by their ability to discriminate sequences known to contain binding sites from those without. The CB-MAR and scoring techniques have a 0.86 and 0.73 median rank correlation using ChIP-seq and PBM respectively. Best motifs selected by CB-MAR achieve a mean AUC of 0.75, comparable to those ranked by held out data at 0.76 { this is based on ChIP-seq motif discovery using five algorithms on 110 transcription factors. We have demonstrated the benefit of this web server in motif choice and ranking, as well as in motif.
- Full Text:
- Date Issued: 2016
Mapping epistemic cultures and learning potential of participants in citizen science projects
- Vallabh, Priya, Lotz-Sisitka, Heila, O'Donoghue, Rob, Schudel, Ingrid J
- Authors: Vallabh, Priya , Lotz-Sisitka, Heila , O'Donoghue, Rob , Schudel, Ingrid J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128939 , vital:36192 , https://doi.org/10.1111/cobi.12701
- Description: The ever-widening scope and range of global change and interconnected systemic risks arising from people–environment relationships (social‐ecological risks) appears to be increasing concern among, and involvement of, citizens in an increasingly diversified number of citizen science projects responding to these risks. We examined the relationship between epistemic cultures in citizen science projects and learning potential related to matters of concern. We then developed a typology of purposes and a citizen science epistemic‐cultures heuristic and mapped 56 projects in southern Africa using this framework. The purpose typology represents the range of knowledge‐production purposes, ranging from laboratory science to social learning, whereas the epistemic‐cultures typology is a relational representation of scientist and citizen participation and their approach to knowledge production. Results showed an iterative relationship between matters of fact and matters of concern across the projects; the nexus of citizens’ engagement in knowledge‐production activities varied. The knowledge‐production purposes informed and shaped the epistemic cultures of all the sampled citizen science projects, which in turn influenced the potential for learning within each project. Through a historical review of 3 phases in a long‐term river health‐monitoring project, we found that it is possible to evolve the learning curve of citizen science projects. This evolution involved the development of scientific water monitoring tools, the parallel development of pedagogic practices supporting monitoring activities, and situated engagement around matters of concern within social activism leading to learning‐led change. We conclude that such evolutionary processes serve to increase potential for learning and are necessary if citizen science is to contribute to wider restructuring of the epistemic culture of science under conditions of expanding social-ecological risk.
- Full Text:
- Date Issued: 2016
- Authors: Vallabh, Priya , Lotz-Sisitka, Heila , O'Donoghue, Rob , Schudel, Ingrid J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128939 , vital:36192 , https://doi.org/10.1111/cobi.12701
- Description: The ever-widening scope and range of global change and interconnected systemic risks arising from people–environment relationships (social‐ecological risks) appears to be increasing concern among, and involvement of, citizens in an increasingly diversified number of citizen science projects responding to these risks. We examined the relationship between epistemic cultures in citizen science projects and learning potential related to matters of concern. We then developed a typology of purposes and a citizen science epistemic‐cultures heuristic and mapped 56 projects in southern Africa using this framework. The purpose typology represents the range of knowledge‐production purposes, ranging from laboratory science to social learning, whereas the epistemic‐cultures typology is a relational representation of scientist and citizen participation and their approach to knowledge production. Results showed an iterative relationship between matters of fact and matters of concern across the projects; the nexus of citizens’ engagement in knowledge‐production activities varied. The knowledge‐production purposes informed and shaped the epistemic cultures of all the sampled citizen science projects, which in turn influenced the potential for learning within each project. Through a historical review of 3 phases in a long‐term river health‐monitoring project, we found that it is possible to evolve the learning curve of citizen science projects. This evolution involved the development of scientific water monitoring tools, the parallel development of pedagogic practices supporting monitoring activities, and situated engagement around matters of concern within social activism leading to learning‐led change. We conclude that such evolutionary processes serve to increase potential for learning and are necessary if citizen science is to contribute to wider restructuring of the epistemic culture of science under conditions of expanding social-ecological risk.
- Full Text:
- Date Issued: 2016
The limitations of current health literacy measures for use in developing countries:
- Authors: Dowse, Roslind
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156607 , vital:40030 , DOI: 10.1080/17538068.2016.1147742
- Description: Health literacy measures have largely emanated from developed countries, reflecting the characteristics of their economies, populations, and health systems. In contrast, it is disconcerting that health literacy appears to be so under-researched in developing countries (DCs), despite the likelihood of inadequate health literacy being endemic. In this commentary, I highlight some challenges when using existing health literacy measures in DCs and conclude with a summary of considerations when using/developing a tool for these populations.
- Full Text:
- Date Issued: 2016
- Authors: Dowse, Roslind
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156607 , vital:40030 , DOI: 10.1080/17538068.2016.1147742
- Description: Health literacy measures have largely emanated from developed countries, reflecting the characteristics of their economies, populations, and health systems. In contrast, it is disconcerting that health literacy appears to be so under-researched in developing countries (DCs), despite the likelihood of inadequate health literacy being endemic. In this commentary, I highlight some challenges when using existing health literacy measures in DCs and conclude with a summary of considerations when using/developing a tool for these populations.
- Full Text:
- Date Issued: 2016
Thermoluminescence of kunzite: a study of kinetic processes and dosimetry characteristics
- Ogundare, F O, Alatishe, M A, Chithambo, Makaiko L, Costin, G
- Authors: Ogundare, F O , Alatishe, M A , Chithambo, Makaiko L , Costin, G
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124701 , vital:35650 , https://doi.org/10.1016/j.nimb.2016.02.059
- Description: Since the use of natural minerals for dating and dose reconstruction using luminescence techniques is well-established and always of interest, we present thermoluminescence characteristics of kunzite, a gem variety of spodumene. The chemical composition of the sample was determined using an Electron Probe MicroAnalyzer.
- Full Text: false
- Date Issued: 2016
- Authors: Ogundare, F O , Alatishe, M A , Chithambo, Makaiko L , Costin, G
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124701 , vital:35650 , https://doi.org/10.1016/j.nimb.2016.02.059
- Description: Since the use of natural minerals for dating and dose reconstruction using luminescence techniques is well-established and always of interest, we present thermoluminescence characteristics of kunzite, a gem variety of spodumene. The chemical composition of the sample was determined using an Electron Probe MicroAnalyzer.
- Full Text: false
- Date Issued: 2016