Case Studies for UNECCC, UNESCO and CEE The COPART Climate Train
- Authors: McGarry, Dylan K
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391120 , vital:68622 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-2016_18-July-issue-42.pdf"
- Description: To create a listening and educational platform that used various disciplines to understand the impact of Climate Change across South Africa. The objective was to create a multigenre educational space for citizens of South Africa as a means to participate in Climate discussions as an alternative to the COP17 negotiations held in South Africa at the time.
- Full Text:
- Date Issued: 2016
- Authors: McGarry, Dylan K
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391120 , vital:68622 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-2016_18-July-issue-42.pdf"
- Description: To create a listening and educational platform that used various disciplines to understand the impact of Climate Change across South Africa. The objective was to create a multigenre educational space for citizens of South Africa as a means to participate in Climate discussions as an alternative to the COP17 negotiations held in South Africa at the time.
- Full Text:
- Date Issued: 2016
The National Wellbeing Index in the isiXhosa translation: focus group discussions on how South Africans view the quality of their society
- Moller, Valerie, Roberts, Benjamin J, Zani, Dalindyebo
- Authors: Moller, Valerie , Roberts, Benjamin J , Zani, Dalindyebo
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67135 , vital:29035 , https://doi.org/10.1007/s11205-016-1481-4
- Description: publisher version , The International Wellbeing Index covers two complementary measures, the Personal Wellbeing Index (PWI) and the National Wellbeing Index (NWI). The focus group study reported here tested the understanding of the NWI when translated into isiXhosa, a language spoken by 6 million South Africans, or 16% of the country’s population. A challenge for the NWI in measuring national well-being is the tendency for meaning to get ‘lost in translation’ in the wording of the instrument, owing to the disparities that exist between levels of living in developed and developing nations. The focussed discussions with native isiXhosa speakers conveyed the different shades of meaning associated with the six domains that make up the NWI. The isiXhosa keywords for the domains of social conditions, the natural environment, national security, and management of the country’s affairs (government) were readily understood, but discussants asked for further clarification of keywords for the domains relating to the economy and business. Conversations showed up the close link between personal and national well-being: discussants drew upon their personal and parochial life experiences along with their knowledge of current affairs to evaluate the nation’s quality of life. They described the social contract between citizens and their government to create a ‘caring society’ that promotes well-being across key domains of national life. Many of the reference standards used to evaluate national well-being were ones postulated to influence personal well-being (Michalos A.C, Social Indicators Research 16(4): 347–413 1985 ). The study also pointed to a potential problem for longitudinal studies if the bipolar satisfaction scale, formerly used to measure the International Wellbeing Index’s PWI and NWI, is changed to a unipolar one. Findings from this pilot study confirm the potential of the NWI as a tool for measuring national well-being cross-culturally.
- Full Text: false
- Date Issued: 2018
- Authors: Moller, Valerie , Roberts, Benjamin J , Zani, Dalindyebo
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67135 , vital:29035 , https://doi.org/10.1007/s11205-016-1481-4
- Description: publisher version , The International Wellbeing Index covers two complementary measures, the Personal Wellbeing Index (PWI) and the National Wellbeing Index (NWI). The focus group study reported here tested the understanding of the NWI when translated into isiXhosa, a language spoken by 6 million South Africans, or 16% of the country’s population. A challenge for the NWI in measuring national well-being is the tendency for meaning to get ‘lost in translation’ in the wording of the instrument, owing to the disparities that exist between levels of living in developed and developing nations. The focussed discussions with native isiXhosa speakers conveyed the different shades of meaning associated with the six domains that make up the NWI. The isiXhosa keywords for the domains of social conditions, the natural environment, national security, and management of the country’s affairs (government) were readily understood, but discussants asked for further clarification of keywords for the domains relating to the economy and business. Conversations showed up the close link between personal and national well-being: discussants drew upon their personal and parochial life experiences along with their knowledge of current affairs to evaluate the nation’s quality of life. They described the social contract between citizens and their government to create a ‘caring society’ that promotes well-being across key domains of national life. Many of the reference standards used to evaluate national well-being were ones postulated to influence personal well-being (Michalos A.C, Social Indicators Research 16(4): 347–413 1985 ). The study also pointed to a potential problem for longitudinal studies if the bipolar satisfaction scale, formerly used to measure the International Wellbeing Index’s PWI and NWI, is changed to a unipolar one. Findings from this pilot study confirm the potential of the NWI as a tool for measuring national well-being cross-culturally.
- Full Text: false
- Date Issued: 2018
Partial cold treatment of citrus fruit for export risk mitigation for Thaumatotibia leucotreta (Lepidoptera: Tortricidae) as part of a systems approach
- Moore, Sean D, Kirkman, Wayne, Albertyn, Sonnica, Love, C N, Coetzee, Julie A, Hattingh, V
- Authors: Moore, Sean D , Kirkman, Wayne , Albertyn, Sonnica , Love, C N , Coetzee, Julie A , Hattingh, V
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423796 , vital:72094 , xlink:href="https://doi.org/10.1093/jee/tow138"
- Description: Some of South Africa’s citrus export markets require mandatory postharvest cold treatment of citrus fruit as a phytosanitary risk mitigation treatment for Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). An alternative to this may be partial cold treatment as one of the final steps in a systems approach to mitigate phytosanitary risk. Consequently, the efficacy of such partial cold treatments was evaluated. It was first determined that a 2C cold treatment was significantly more effective against fourth and fifth instars (the most cold-tolerant instars) than treatments at 3C and 4C for a duration of 18 d. Secondly, it was determined that 2C for 18 d and 1C for 16 d were similarly effective, but both treatments were significantly more effective than 1C for 14 d. Mean mortality of fourth and fifth instars treated with 2C for 18 d in seven replicates from four trials was 99.94%. Finally, it was determined that the inability of the majority of surviving larvae to develop to adulthood would further increase the efficacy of a 2C for 18 d treatment to 99.96%. Inclusion of reproductive nonviability of survivors increased mortality to 99.99%.
- Full Text:
- Date Issued: 2016
- Authors: Moore, Sean D , Kirkman, Wayne , Albertyn, Sonnica , Love, C N , Coetzee, Julie A , Hattingh, V
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423796 , vital:72094 , xlink:href="https://doi.org/10.1093/jee/tow138"
- Description: Some of South Africa’s citrus export markets require mandatory postharvest cold treatment of citrus fruit as a phytosanitary risk mitigation treatment for Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). An alternative to this may be partial cold treatment as one of the final steps in a systems approach to mitigate phytosanitary risk. Consequently, the efficacy of such partial cold treatments was evaluated. It was first determined that a 2C cold treatment was significantly more effective against fourth and fifth instars (the most cold-tolerant instars) than treatments at 3C and 4C for a duration of 18 d. Secondly, it was determined that 2C for 18 d and 1C for 16 d were similarly effective, but both treatments were significantly more effective than 1C for 14 d. Mean mortality of fourth and fifth instars treated with 2C for 18 d in seven replicates from four trials was 99.94%. Finally, it was determined that the inability of the majority of surviving larvae to develop to adulthood would further increase the efficacy of a 2C for 18 d treatment to 99.96%. Inclusion of reproductive nonviability of survivors increased mortality to 99.99%.
- Full Text:
- Date Issued: 2016
Bioinformatic characterization of type-specific sequence and structural features in auxiliary activity family 9 proteins:
- Moses, Vuyani, Hatherley, Rowan, Tastan Bishop, Özlem
- Authors: Moses, Vuyani , Hatherley, Rowan , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148358 , vital:38732 , DOI: 10.1186/s13068-016-0655-2
- Description: Due to the impending depletion of fossil fuels, it has become important to identify alternative energy sources. The biofuel industry has proven to be a promising alternative. However, owing to the complex nature of plant biomass, hence the degradation, biofuel production remains a challenge. The copper-dependent Auxiliary Activity family 9 (AA9) proteins have been found to act synergistically with other cellulose-degrading enzymes resulting in an increased rate of cellulose breakdown. AA9 proteins are lytic polysaccharide monooxygenase (LPMO) enzymes, otherwise known as polysaccharide monooxygenases (PMOs). They are further classified as Type 1, 2 or 3 PMOs, depending on the different cleavage products formed. As AA9 proteins are known to exhibit low sequence conservation, the analysis of unique features of AA9 domains of these enzymes should provide insights for the better understanding of how different AA9 PMO types function.
- Full Text:
- Date Issued: 2016
- Authors: Moses, Vuyani , Hatherley, Rowan , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148358 , vital:38732 , DOI: 10.1186/s13068-016-0655-2
- Description: Due to the impending depletion of fossil fuels, it has become important to identify alternative energy sources. The biofuel industry has proven to be a promising alternative. However, owing to the complex nature of plant biomass, hence the degradation, biofuel production remains a challenge. The copper-dependent Auxiliary Activity family 9 (AA9) proteins have been found to act synergistically with other cellulose-degrading enzymes resulting in an increased rate of cellulose breakdown. AA9 proteins are lytic polysaccharide monooxygenase (LPMO) enzymes, otherwise known as polysaccharide monooxygenases (PMOs). They are further classified as Type 1, 2 or 3 PMOs, depending on the different cleavage products formed. As AA9 proteins are known to exhibit low sequence conservation, the analysis of unique features of AA9 domains of these enzymes should provide insights for the better understanding of how different AA9 PMO types function.
- Full Text:
- Date Issued: 2016
Decoupled reciprocal subsidies of biomass and fatty acids in fluxes of invertebrates between a temperate river and the adjacent land:
- Moyo, Sydney, Chari, Lenin D, Villet, Martin H, Richoux, Nicole B
- Authors: Moyo, Sydney , Chari, Lenin D , Villet, Martin H , Richoux, Nicole B
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140843 , vital:37923 , DOI: 10.1007/s00027-017-0529-0
- Description: Streams and riparian areas are tightly coupled through reciprocal trophic subsidies, and there is evidence that these subsidies affect consumers in connected ecosystems. Most studies of subsidies consider only their quantity and not their quality. We determined the bidirectional exchange of organisms between the Kowie River and its riparian zone in South Africa using floating pyramidal traps (to measure insect emergence) and pan traps (to capture infalling invertebrates).
- Full Text:
- Date Issued: 2017
- Authors: Moyo, Sydney , Chari, Lenin D , Villet, Martin H , Richoux, Nicole B
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140843 , vital:37923 , DOI: 10.1007/s00027-017-0529-0
- Description: Streams and riparian areas are tightly coupled through reciprocal trophic subsidies, and there is evidence that these subsidies affect consumers in connected ecosystems. Most studies of subsidies consider only their quantity and not their quality. We determined the bidirectional exchange of organisms between the Kowie River and its riparian zone in South Africa using floating pyramidal traps (to measure insect emergence) and pan traps (to capture infalling invertebrates).
- Full Text:
- Date Issued: 2017
Encouraging pro-environmental behaviour: energy use and recycling at Rhodes University, South Africa
- Mtutu, Paidamoyo, Thondhlana, Gladman
- Authors: Mtutu, Paidamoyo , Thondhlana, Gladman
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67743 , vital:29136 , https://doi.org/10.1016/j.habitatint.2015.11.031
- Description: Publisher version , The rapid expansion of student numbers, staff and support infrastructures in higher education institutions often result in increased demand for resources such as energy and paper. Promoting pro-environmental behaviour is critical if higher education institutions are to achieve sustainable resource use. Using surveys, reported energy use and recycling behaviour of staff and students in the Faculty of Education at Rhodes University, South Africa was explored. The results showed that self-reported pro-environmental behaviour was mediated by demographic factors and personal values such as ‘liking of aesthetic beauty and biodiversity’, ‘social relations’, ‘a varied life’ and ‘freedom’. Personal values, though key in shaping participants' attitudes toward the environment did not always translate into pro-environmental behaviour. Situational factors beyond the control of participants were cited as barriers to pro-environmental actions. Lessons from this study point to the need to carefully study the assumptions underlying intervention strategies aimed at promoting pro-environmental behaviour and to get rid of barriers to enable pro-environmental actions.
- Full Text: false
- Date Issued: 2016
Encouraging pro-environmental behaviour: energy use and recycling at Rhodes University, South Africa
- Authors: Mtutu, Paidamoyo , Thondhlana, Gladman
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67743 , vital:29136 , https://doi.org/10.1016/j.habitatint.2015.11.031
- Description: Publisher version , The rapid expansion of student numbers, staff and support infrastructures in higher education institutions often result in increased demand for resources such as energy and paper. Promoting pro-environmental behaviour is critical if higher education institutions are to achieve sustainable resource use. Using surveys, reported energy use and recycling behaviour of staff and students in the Faculty of Education at Rhodes University, South Africa was explored. The results showed that self-reported pro-environmental behaviour was mediated by demographic factors and personal values such as ‘liking of aesthetic beauty and biodiversity’, ‘social relations’, ‘a varied life’ and ‘freedom’. Personal values, though key in shaping participants' attitudes toward the environment did not always translate into pro-environmental behaviour. Situational factors beyond the control of participants were cited as barriers to pro-environmental actions. Lessons from this study point to the need to carefully study the assumptions underlying intervention strategies aimed at promoting pro-environmental behaviour and to get rid of barriers to enable pro-environmental actions.
- Full Text: false
- Date Issued: 2016
The development of computational biology in South Africa: successes achieved and lessons learnt
- Mulder, Nicola J, Christoffels, Alan, De Oliveira, Tulio, Gamieldien, Junaid, Hazelhurst, Scott, Joubert, Fourie, Kumuthini, Judit, Pillay, Ché S, Snoep, Jacky L, Tastan Bishop, Özlem, Tiffin, Nicki
- Authors: Mulder, Nicola J , Christoffels, Alan , De Oliveira, Tulio , Gamieldien, Junaid , Hazelhurst, Scott , Joubert, Fourie , Kumuthini, Judit , Pillay, Ché S , Snoep, Jacky L , Tastan Bishop, Özlem , Tiffin, Nicki
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148347 , vital:38731 , DOI: 10.1371/journal.pcbi.1004395
- Description: Bioinformatics is now a critical skill in many research and commercial environments as biological data are increasing in both size and complexity. South African researchers recognized this need in the mid-1990s and responded by working with the government as well as international bodies to develop initiatives to build bioinformatics capacity in the country. Significant injections of support from these bodies provided a springboard for the establishment of computational biology units at multiple universities throughout the country, which took on teaching, basic research and support roles. Several challenges were encountered, for example with unreliability of funding, lack of skills, and lack of infrastructure. However, the bioinformatics community worked together to overcome these, and South Africa is now arguably the leading country in bioinformatics on the African continent. Here we discuss how the discipline developed in the country, highlighting the challenges, successes, and lessons learnt.
- Full Text:
- Date Issued: 2016
- Authors: Mulder, Nicola J , Christoffels, Alan , De Oliveira, Tulio , Gamieldien, Junaid , Hazelhurst, Scott , Joubert, Fourie , Kumuthini, Judit , Pillay, Ché S , Snoep, Jacky L , Tastan Bishop, Özlem , Tiffin, Nicki
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148347 , vital:38731 , DOI: 10.1371/journal.pcbi.1004395
- Description: Bioinformatics is now a critical skill in many research and commercial environments as biological data are increasing in both size and complexity. South African researchers recognized this need in the mid-1990s and responded by working with the government as well as international bodies to develop initiatives to build bioinformatics capacity in the country. Significant injections of support from these bodies provided a springboard for the establishment of computational biology units at multiple universities throughout the country, which took on teaching, basic research and support roles. Several challenges were encountered, for example with unreliability of funding, lack of skills, and lack of infrastructure. However, the bioinformatics community worked together to overcome these, and South Africa is now arguably the leading country in bioinformatics on the African continent. Here we discuss how the discipline developed in the country, highlighting the challenges, successes, and lessons learnt.
- Full Text:
- Date Issued: 2016
Water footprint assessment of citrus production in South Africa: A case study of the Lower Sundays River Valley
- Munro, Samantha A, Fraser, Gavin C G, Snowball, Jeanette D, Pahlow, Markus
- Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
- Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
- Full Text: false
- Date Issued: 2016
- Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
- Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
- Full Text: false
- Date Issued: 2016
Analysis of non-peptidic compounds as potential malarial inhibitors against plasmodial cysteine proteases via integrated virtual screening workflow
- Musyoka, Thommas M, Kanzi, Aquillah M, Lobb, Kevin A, Tastan Bishop, Özlem
- Authors: Musyoka, Thommas M , Kanzi, Aquillah M , Lobb, Kevin A , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123074 , vital:35403 , https://doi.10.1080/07391102.2015.1108231
- Description: Malaria is an infectious disease caused by a diverse group of erythrocytic protozoan parasites of the genus Plasmodium. It remains an exigent public health problem in the tropical areas of Africa, South America and parts of Asia and continues to take its toll in morbidity and mortality with half of the world’s population under a permanent risk of infection leading to more than half a million deaths annually (WHO, 2013). Five Plasmodium species, namely P. falciparum (Pf ), P. vivax (Pv), P. ovale (Po), P. malariae (Pm) and P. knowlesi (Pk), are known to infect humans with Pf responsible for more than 90% of the malarial fatalities reported in sub-Saharan Africa. The predominance of Pf is attributed to its adaptability (Ashley, McGready, Proux, & Nosten, 2006; Prugnolle et al., 2011). Although the high occurrence of the Duffy negative trait among African populations lowers the threat posed by Pv, it is the most frequent and widely causative agent of benign tertian malaria in other parts of the world (Mendis, Sina, Marchesini, & Carter, 2001). In addition to the listed human malarial parasite forms, several other Plasmodium species, which infect non-human laboratory models, have been identified and are of significant importance in understanding the parasite biology, the host–parasite interactions and in the drug development process (Langhorne et al., 2011).
- Full Text:
- Date Issued: 2016
- Authors: Musyoka, Thommas M , Kanzi, Aquillah M , Lobb, Kevin A , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123074 , vital:35403 , https://doi.10.1080/07391102.2015.1108231
- Description: Malaria is an infectious disease caused by a diverse group of erythrocytic protozoan parasites of the genus Plasmodium. It remains an exigent public health problem in the tropical areas of Africa, South America and parts of Asia and continues to take its toll in morbidity and mortality with half of the world’s population under a permanent risk of infection leading to more than half a million deaths annually (WHO, 2013). Five Plasmodium species, namely P. falciparum (Pf ), P. vivax (Pv), P. ovale (Po), P. malariae (Pm) and P. knowlesi (Pk), are known to infect humans with Pf responsible for more than 90% of the malarial fatalities reported in sub-Saharan Africa. The predominance of Pf is attributed to its adaptability (Ashley, McGready, Proux, & Nosten, 2006; Prugnolle et al., 2011). Although the high occurrence of the Duffy negative trait among African populations lowers the threat posed by Pv, it is the most frequent and widely causative agent of benign tertian malaria in other parts of the world (Mendis, Sina, Marchesini, & Carter, 2001). In addition to the listed human malarial parasite forms, several other Plasmodium species, which infect non-human laboratory models, have been identified and are of significant importance in understanding the parasite biology, the host–parasite interactions and in the drug development process (Langhorne et al., 2011).
- Full Text:
- Date Issued: 2016
Structure based docking and molecular dynamic studies of plasmodial cysteine proteases against a South African natural compound and its analogs:
- Musyoka, Thommas M, Kanzi, Aquillah M, Lobb, Kevin A, Tastan Bishop, Özlem
- Authors: Musyoka, Thommas M , Kanzi, Aquillah M , Lobb, Kevin A , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148027 , vital:38703 , DOI: 10.1038/srep23690
- Description: Identification of potential drug targets as well as development of novel antimalarial chemotherapies with unique mode of actions due to drug resistance by Plasmodium parasites are inevitable. Falcipains (falcipain-2 and falcipain-3) of Plasmodium falciparum, which catalyse the haemoglobin degradation process, are validated drug targets. Previous attempts to develop peptide based drugs against these enzymes have been futile due to the poor pharmacological profiles and susceptibility to degradation by host enzymes. This study aimed to identify potential non-peptide inhibitors against falcipains and their homologs from other Plasmodium species.
- Full Text:
- Date Issued: 2016
- Authors: Musyoka, Thommas M , Kanzi, Aquillah M , Lobb, Kevin A , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148027 , vital:38703 , DOI: 10.1038/srep23690
- Description: Identification of potential drug targets as well as development of novel antimalarial chemotherapies with unique mode of actions due to drug resistance by Plasmodium parasites are inevitable. Falcipains (falcipain-2 and falcipain-3) of Plasmodium falciparum, which catalyse the haemoglobin degradation process, are validated drug targets. Previous attempts to develop peptide based drugs against these enzymes have been futile due to the poor pharmacological profiles and susceptibility to degradation by host enzymes. This study aimed to identify potential non-peptide inhibitors against falcipains and their homologs from other Plasmodium species.
- Full Text:
- Date Issued: 2016
Development and assessment of a USP Apparatus 3 dissolution test method for sustained-release Nevirapine matrix tablets
- Mwila, Chiluba, Khamanga, Sandile M M, Walker, Roderick B
- Authors: Mwila, Chiluba , Khamanga, Sandile M M , Walker, Roderick B
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184779 , vital:44271 , xlink:href="https://doi.org/10.14227/dt230316p22"
- Description: Dissolution testing is a quality control tool used to assess batch-to-batch performance of dosage forms, thereby providing continued assurance of product quality. Analytical methods for the assessment of pharmaceutical product quality must be validated according to regulatory guidelines to ensure that tests are reliable and valid. Agitation rate, mesh pore size, surfactant concentration, and dissolution medium molarity are experimental parameters that may affect nevirapine (NVP) release and were investigated and optimized to ensure that consistent, reliable, and valid results using Apparatus 3 were produced. Agitation rate was investigated to establish an equivalent response to that observed for NVP release using Apparatus 2 at 50 rpm. A reciprocation rate of 5–10 dpm produced dissolution profiles that were similar to those observed using Apparatus 2. An increase in the molarity of the dissolution medium slightly increased the release rate of NVP, and a 50 mM buffer maintained at pH values mimicking gastrointestinal tract (GIT) conditions was selected for all experiments. With the addition of 2% sodium lauryl sulfate (SLS) to the dissolution medium, >80% NVP was released from the tablets over the test period. The NVP release rate increased with an increase in the mesh pore size; however, the extent of release was not affected by this parameter. Dissolution test samples were analyzed using HPLC, and dissolution methods were validated for NVP stability in the dissolution medium, specificity, linearity and range, repeatability, intermediate precision, and accuracy as defined by ICH. The dissolution method used for testing NVP tablets can be regarded as an appropriate tool for the evaluation of sustained-release (SR) NVP formulations and the impact of formulation composition and product quality attributes on drug release.
- Full Text:
- Date Issued: 2016
- Authors: Mwila, Chiluba , Khamanga, Sandile M M , Walker, Roderick B
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184779 , vital:44271 , xlink:href="https://doi.org/10.14227/dt230316p22"
- Description: Dissolution testing is a quality control tool used to assess batch-to-batch performance of dosage forms, thereby providing continued assurance of product quality. Analytical methods for the assessment of pharmaceutical product quality must be validated according to regulatory guidelines to ensure that tests are reliable and valid. Agitation rate, mesh pore size, surfactant concentration, and dissolution medium molarity are experimental parameters that may affect nevirapine (NVP) release and were investigated and optimized to ensure that consistent, reliable, and valid results using Apparatus 3 were produced. Agitation rate was investigated to establish an equivalent response to that observed for NVP release using Apparatus 2 at 50 rpm. A reciprocation rate of 5–10 dpm produced dissolution profiles that were similar to those observed using Apparatus 2. An increase in the molarity of the dissolution medium slightly increased the release rate of NVP, and a 50 mM buffer maintained at pH values mimicking gastrointestinal tract (GIT) conditions was selected for all experiments. With the addition of 2% sodium lauryl sulfate (SLS) to the dissolution medium, >80% NVP was released from the tablets over the test period. The NVP release rate increased with an increase in the mesh pore size; however, the extent of release was not affected by this parameter. Dissolution test samples were analyzed using HPLC, and dissolution methods were validated for NVP stability in the dissolution medium, specificity, linearity and range, repeatability, intermediate precision, and accuracy as defined by ICH. The dissolution method used for testing NVP tablets can be regarded as an appropriate tool for the evaluation of sustained-release (SR) NVP formulations and the impact of formulation composition and product quality attributes on drug release.
- Full Text:
- Date Issued: 2016
An analysis of how students construct knowledge in a course with a hierarchical knowledge structure
- Authors: Myers, Peta L
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66995 , vital:29014 , https://doi.org/10.1080/10291954.2016.1196528
- Description: publisher version , Passing the introductory accounting semester is often seen as a challenge for first year students. Being aware of both effective and ineffective ways of constructing knowledge in a discipline with a hierarchical knowledge structure will be of value to students and teachers alike in assisting in the development of effective styles of learning. This article, which is part of a larger body of research, analyses how students in an introductory financial accounting class at Rhodes University constructed knowledge. Previous research described the course as having a hierarchical knowledge structure. In this research, first year accounting students at Rhodes University were interviewed to gain an improved understanding of how they constructed knowledge in this course. This article describes how students who were successful in passing this semester course used similar, effective ways of constructing knowledge, while students who were not successful also employed similar but less effective ways of constructing knowledge. These different ways of constructing knowledge, both effective and ineffective, were analysed, using the Bernstein’s pedagogic device and Maton’s Legitimation Code Theory. This article provides those involved in teaching and learning in a discipline with a hierarchical knowledge structure, with a theoretical explanation of why some methods of constructing knowledge are more effective than others. Understanding and being explicit about more (and less) effective ways of constructing knowledge in a course with a hierarchical knowledge structure can guide those involved in teaching and learning to improve results.
- Full Text: false
- Date Issued: 2016
- Authors: Myers, Peta L
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66995 , vital:29014 , https://doi.org/10.1080/10291954.2016.1196528
- Description: publisher version , Passing the introductory accounting semester is often seen as a challenge for first year students. Being aware of both effective and ineffective ways of constructing knowledge in a discipline with a hierarchical knowledge structure will be of value to students and teachers alike in assisting in the development of effective styles of learning. This article, which is part of a larger body of research, analyses how students in an introductory financial accounting class at Rhodes University constructed knowledge. Previous research described the course as having a hierarchical knowledge structure. In this research, first year accounting students at Rhodes University were interviewed to gain an improved understanding of how they constructed knowledge in this course. This article describes how students who were successful in passing this semester course used similar, effective ways of constructing knowledge, while students who were not successful also employed similar but less effective ways of constructing knowledge. These different ways of constructing knowledge, both effective and ineffective, were analysed, using the Bernstein’s pedagogic device and Maton’s Legitimation Code Theory. This article provides those involved in teaching and learning in a discipline with a hierarchical knowledge structure, with a theoretical explanation of why some methods of constructing knowledge are more effective than others. Understanding and being explicit about more (and less) effective ways of constructing knowledge in a course with a hierarchical knowledge structure can guide those involved in teaching and learning to improve results.
- Full Text: false
- Date Issued: 2016
Impacts of HIV/AIDS on food consumption and wild food use in rural South Africa
- Ncube, Keitometsi, Shackleton, Charlie M, Swallow, Brent M, Dassanayake, Wijaya
- Authors: Ncube, Keitometsi , Shackleton, Charlie M , Swallow, Brent M , Dassanayake, Wijaya
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180412 , vital:43385 , xlink:href="https://doi.org/10.1007/s12571-016-0624-4"
- Description: HIV/AIDS can affect household food consumption in many ways, including through reductions in availability and quality of labour, reductions in earned income, and increased expenditure on medications. In rural South Africa, these negative effects can be buffered by social safety net programs provided by government and collection of wild foods. Despite some acknowledgement of the potential safety net role of wild foods, however, their contribution relative to other food sources in the context of HIV/AIDS remains underexplored. Here we report empirical findings from two rural communities in the Eastern Cape province of South Africa. Qualitative and quantitative methods were used to characterise food sources, intake and calories from 68 HIV/AIDS afflicted households and 87 non-afflicted households every quarter over 12 months. Results show that diets were moderately well-balanced though limited in variety, with cereal items contributing 52 % to total calorie intake. The bulk of food consumed by households was purchased, with supplementation from own production, collected wild vegetables and collected wild fruits. Up to 20 % of respondents from both HIV/ AIDS afflicted and non-afflicted households had insufficient daily caloric intake. Multivariate analyses show that, all else equal, individuals living in households afflicted by HIV/AIDS consumed fewer calories, had less diverse diets, and were more dependent on wild foods than those living in non-afflicted households. Given the detrimental effects of HIV/AIDS on income and home production, wild foods represent a free and readily available food source for vulnerable households.
- Full Text:
- Date Issued: 2016
- Authors: Ncube, Keitometsi , Shackleton, Charlie M , Swallow, Brent M , Dassanayake, Wijaya
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180412 , vital:43385 , xlink:href="https://doi.org/10.1007/s12571-016-0624-4"
- Description: HIV/AIDS can affect household food consumption in many ways, including through reductions in availability and quality of labour, reductions in earned income, and increased expenditure on medications. In rural South Africa, these negative effects can be buffered by social safety net programs provided by government and collection of wild foods. Despite some acknowledgement of the potential safety net role of wild foods, however, their contribution relative to other food sources in the context of HIV/AIDS remains underexplored. Here we report empirical findings from two rural communities in the Eastern Cape province of South Africa. Qualitative and quantitative methods were used to characterise food sources, intake and calories from 68 HIV/AIDS afflicted households and 87 non-afflicted households every quarter over 12 months. Results show that diets were moderately well-balanced though limited in variety, with cereal items contributing 52 % to total calorie intake. The bulk of food consumed by households was purchased, with supplementation from own production, collected wild vegetables and collected wild fruits. Up to 20 % of respondents from both HIV/ AIDS afflicted and non-afflicted households had insufficient daily caloric intake. Multivariate analyses show that, all else equal, individuals living in households afflicted by HIV/AIDS consumed fewer calories, had less diverse diets, and were more dependent on wild foods than those living in non-afflicted households. Given the detrimental effects of HIV/AIDS on income and home production, wild foods represent a free and readily available food source for vulnerable households.
- Full Text:
- Date Issued: 2016
Diet of the endemic bivalve Solen cylindraceus inferred from stable isotope analysis in the Kariega Estuary, South Africa
- Nel, Holly A, Froneman, P William
- Authors: Nel, Holly A , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67933 , vital:29170 , https://doi.org/10.1080/13235818.2016.1175917
- Description: Publisher version , Sedentary filter-feeders such as the razor clam (Solen cylindraceus) are believed to indiscriminately exploit a carbon source derived from particulate organic matter (POM). POM demonstrates a high degree of spatial and temporal variability in composition, which may result in intraspecific dietary variation. This study aimed to investigate seasonal ontogenetic shifts in the feeding ecology of S. cylindraceus using dual stable isotopic (δ13C and δ15N) analyses in the oligotrophic temperate permanently open Kariega Estuary, South Africa. Mixing model results demonstrate that the different size classes of S. cylindraceus had a diet comprised mainly of POM. However, size grouping did have a significant effect on carbon and nitrogen signatures. Specifically, during winter, carbon isotopic signatures became more depleted with a decrease in size, while both winter and summer δ15N values became more nitrogen enriched with an increase in size. The observed trend in the ratios can likely be ascribed to the hydrodynamics of the system. Data from this study suggest that there may be some degree of variation among the different size cohorts, although this needs further investigation.
- Full Text: false
- Date Issued: 2016
- Authors: Nel, Holly A , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67933 , vital:29170 , https://doi.org/10.1080/13235818.2016.1175917
- Description: Publisher version , Sedentary filter-feeders such as the razor clam (Solen cylindraceus) are believed to indiscriminately exploit a carbon source derived from particulate organic matter (POM). POM demonstrates a high degree of spatial and temporal variability in composition, which may result in intraspecific dietary variation. This study aimed to investigate seasonal ontogenetic shifts in the feeding ecology of S. cylindraceus using dual stable isotopic (δ13C and δ15N) analyses in the oligotrophic temperate permanently open Kariega Estuary, South Africa. Mixing model results demonstrate that the different size classes of S. cylindraceus had a diet comprised mainly of POM. However, size grouping did have a significant effect on carbon and nitrogen signatures. Specifically, during winter, carbon isotopic signatures became more depleted with a decrease in size, while both winter and summer δ15N values became more nitrogen enriched with an increase in size. The observed trend in the ratios can likely be ascribed to the hydrodynamics of the system. Data from this study suggest that there may be some degree of variation among the different size cohorts, although this needs further investigation.
- Full Text: false
- Date Issued: 2016
Schools performing against the odds
- Niacker, Inbanathan, Grant, Carolyn, Pillay, Sivanandani
- Authors: Niacker, Inbanathan , Grant, Carolyn , Pillay, Sivanandani
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281126 , vital:55694 , xlink:href="https://doi.org/10.15700/saje.v36n4a1321"
- Description: There are many schools in developing countries which, despite the challenges they face, defy the odds and continue to perform at exceptionally high levels. We cast our gaze on one of these resilient schools in South Africa, and sought to learn about the leadership practices prevalent in this school and the enablements and constraints to the school leadership practice. Underpinned by a critical realist lens, and drawing on social realist theory, this case study of one school generated data through interviews, observation, document analysis and transect walks. The school principal, one head of department and two teachers, were selected as participants. The findings indicate that the school embraced an expansive form of teacher leadership comprising leadership within and beyond the classroom. Further, the structural, cultural and agential climate was receptive to the expansive leadership. We conclude that the professional capital of teachers, together with teachers serving as social actors rather than remaining primary agents, are key resources to change and transformation in an emerging economy.
- Full Text:
- Date Issued: 2016
- Authors: Niacker, Inbanathan , Grant, Carolyn , Pillay, Sivanandani
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281126 , vital:55694 , xlink:href="https://doi.org/10.15700/saje.v36n4a1321"
- Description: There are many schools in developing countries which, despite the challenges they face, defy the odds and continue to perform at exceptionally high levels. We cast our gaze on one of these resilient schools in South Africa, and sought to learn about the leadership practices prevalent in this school and the enablements and constraints to the school leadership practice. Underpinned by a critical realist lens, and drawing on social realist theory, this case study of one school generated data through interviews, observation, document analysis and transect walks. The school principal, one head of department and two teachers, were selected as participants. The findings indicate that the school embraced an expansive form of teacher leadership comprising leadership within and beyond the classroom. Further, the structural, cultural and agential climate was receptive to the expansive leadership. We conclude that the professional capital of teachers, together with teachers serving as social actors rather than remaining primary agents, are key resources to change and transformation in an emerging economy.
- 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
Decolonising education: visual arts, cohesion, transformation
- Nsele, Z
- Authors: Nsele, Z
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146456 , vital:38527 , https://savah.org.za/2016/01/18/call-for-papers-savah-conference-2016/#more-174
- Description: Rethinking Art History and Visual Culture in a Contemporary Context. The Rhodes Must Fall” and “Fees Must Fall” campaigns which arose in South Africa in the course of 2015, while focused on transformative agendas in a broad sense, also emphasised how various inheritances from the West have played a fundamental role in shaping universities – not only in terms of their curricula but also their institutional cultures more generally. Occurring in a context where the humanities are under threat and where neoliberal forces may upset what we understand as fundamental to the academic project, these recent calls for critical engagement with institutional histories and practices suggest that reconsideration of disciplinary knowledges and understandings have become increasingly urgent.
- Full Text:
- Date Issued: 2016
- Authors: Nsele, Z
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146456 , vital:38527 , https://savah.org.za/2016/01/18/call-for-papers-savah-conference-2016/#more-174
- Description: Rethinking Art History and Visual Culture in a Contemporary Context. The Rhodes Must Fall” and “Fees Must Fall” campaigns which arose in South Africa in the course of 2015, while focused on transformative agendas in a broad sense, also emphasised how various inheritances from the West have played a fundamental role in shaping universities – not only in terms of their curricula but also their institutional cultures more generally. Occurring in a context where the humanities are under threat and where neoliberal forces may upset what we understand as fundamental to the academic project, these recent calls for critical engagement with institutional histories and practices suggest that reconsideration of disciplinary knowledges and understandings have become increasingly urgent.
- Full Text:
- Date Issued: 2016
Post-apartheid nostalgia and the sadomasochistic pleasures of archival art:
- Authors: Nsele, Zamansele
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145598 , vital:38450 , DOI : 10.4314/eia.v43i3.6
- Description: The burgeoning genre of archival art practice in post-apartheid South Africa has catalysed the evocation of nostalgia in abundance. The archive has been at the centre of numerous exhibitions in contemporary art. This paper explores the meaning of an emerging nostalgic turn in post-apartheid South Africa. The discussion considers the pleasure afforded by the sentimentality underpinning nostalgia and attends to the manner in which nostalgia coheres with the creative and aesthetic techniques of archival art. Scopophilia and the covert function of the sadomasochistic gaze are outlined. It is suggested that such acts of retrieval and repetition generally override ethical considerations in part because they unfold from the realm of the unconscious. The paper draws on psychoanalysis by way of Frantz Fanon.
- Full Text:
- Date Issued: 2016
- Authors: Nsele, Zamansele
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145598 , vital:38450 , DOI : 10.4314/eia.v43i3.6
- Description: The burgeoning genre of archival art practice in post-apartheid South Africa has catalysed the evocation of nostalgia in abundance. The archive has been at the centre of numerous exhibitions in contemporary art. This paper explores the meaning of an emerging nostalgic turn in post-apartheid South Africa. The discussion considers the pleasure afforded by the sentimentality underpinning nostalgia and attends to the manner in which nostalgia coheres with the creative and aesthetic techniques of archival art. Scopophilia and the covert function of the sadomasochistic gaze are outlined. It is suggested that such acts of retrieval and repetition generally override ethical considerations in part because they unfold from the realm of the unconscious. The paper draws on psychoanalysis by way of Frantz Fanon.
- 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
Remastered:
- Authors: Ntombela, N
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146423 , vital:38524 , https://www.e-flux.com/announcements/49246/the-exhibitionist-journal-on-exhibition-making/
- Description: Exhibition abstract. Issue 12 scrutinizes our founding premise, that The Exhibitionist is a journal “by curators, for curators.” When we launched six years ago, this circuit of self-reflection seemed necessary, and enabled a conversation that was not available in other venues. But one effect of this focus, as we see it now, was a siloing-off of curatorial thinking from other parts of the field of exhibition making—which is, after all, based in collective forms of authorship.
- Full Text:
- Date Issued: 2016
- Authors: Ntombela, N
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146423 , vital:38524 , https://www.e-flux.com/announcements/49246/the-exhibitionist-journal-on-exhibition-making/
- Description: Exhibition abstract. Issue 12 scrutinizes our founding premise, that The Exhibitionist is a journal “by curators, for curators.” When we launched six years ago, this circuit of self-reflection seemed necessary, and enabled a conversation that was not available in other venues. But one effect of this focus, as we see it now, was a siloing-off of curatorial thinking from other parts of the field of exhibition making—which is, after all, based in collective forms of authorship.
- Full Text:
- Date Issued: 2016