Chinese Cabbage:
- Authors: Mwaba, Stary
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146699 , vital:38549 , https://www.ru.ac.za/artsofafrica/latestnews/rhodesparticipatesintheafrica-chinasymposiumatthegoetheinstitute.html
- Description: Stary Mwaba, an MFA candidate in the Arts of Africa and the Global South research team in the Fine Art Department, presented a paper on his installation, Chinese Cabbage, which was first displayed in his solo exhibition, Life on Mars, at the Künstlerhaus Bethanien in Germany in 2015. At the Africa–China symposium, Mwaba talked about his personal inroad into the Zambia–China debate, which draws from a family history of living along the Tazara Railway that was built by the Chinese in the 1960s, as well as the experience of his daughter attending a Chinese-run international school in Lusaka. Mwaba is currently expanding this research as part of his MFA studies at Rhodes by collecting oral narratives along the line of rail in Zambia and by addressing, through his painting practice, issues pertinent to the controversial copper slug known as Black Mountain in Kitwe.
- Full Text:
- Date Issued: 2017
- Authors: Mwaba, Stary
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146699 , vital:38549 , https://www.ru.ac.za/artsofafrica/latestnews/rhodesparticipatesintheafrica-chinasymposiumatthegoetheinstitute.html
- Description: Stary Mwaba, an MFA candidate in the Arts of Africa and the Global South research team in the Fine Art Department, presented a paper on his installation, Chinese Cabbage, which was first displayed in his solo exhibition, Life on Mars, at the Künstlerhaus Bethanien in Germany in 2015. At the Africa–China symposium, Mwaba talked about his personal inroad into the Zambia–China debate, which draws from a family history of living along the Tazara Railway that was built by the Chinese in the 1960s, as well as the experience of his daughter attending a Chinese-run international school in Lusaka. Mwaba is currently expanding this research as part of his MFA studies at Rhodes by collecting oral narratives along the line of rail in Zambia and by addressing, through his painting practice, issues pertinent to the controversial copper slug known as Black Mountain in Kitwe.
- Full Text:
- Date Issued: 2017
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
Dose response and kinetic analysis of thermoluminescence of Li–Zn fluoroborate glass
- Thomas, Sunil, Chithambo, Makaiko L
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116164 , vital:34326 , https://doi.org/10.1080/10420150.2017.1313844
- Description: The intention of this study is to explore the thermoluminescence properties of beta-irradiated Li–Zn fluoroborate glass. The glow-curve corresponding to 10 Gy shows two peaks when measured at 1°C/s. The dose response of the glass to beta irradiation was investigated. The trapping level parameters such as activation energy, frequency factor and order of kinetics associated with the observed glow-peak were determined using different methods. The thermoluminescence is affected by thermal quenching. A possible mechanism for the thermoluminescence is described.
- Full Text:
- Date Issued: 2017
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116164 , vital:34326 , https://doi.org/10.1080/10420150.2017.1313844
- Description: The intention of this study is to explore the thermoluminescence properties of beta-irradiated Li–Zn fluoroborate glass. The glow-curve corresponding to 10 Gy shows two peaks when measured at 1°C/s. The dose response of the glass to beta irradiation was investigated. The trapping level parameters such as activation energy, frequency factor and order of kinetics associated with the observed glow-peak were determined using different methods. The thermoluminescence is affected by thermal quenching. A possible mechanism for the thermoluminescence is described.
- Full Text:
- Date Issued: 2017
Extended use of grey water for irrigating home gardens in an arid environment
- Al-Ismaili, Abdulrahim M, Ahmed, Mushtaque, Al-Busaidi, Ahmed, Al-Adawi, Seif, Tandlich, Roman, Al-Amri, Mohammed
- Authors: Al-Ismaili, Abdulrahim M , Ahmed, Mushtaque , Al-Busaidi, Ahmed , Al-Adawi, Seif , Tandlich, Roman , Al-Amri, Mohammed
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76048 , vital:30497 , https://doi.org/10.1007/s11356-017-8963-z
- Description: The use of treated grey water (GW) for home gardens, peri-urban agriculture and landscaping is becoming popular in many water stressed countries such as Oman. This study aims to investigate the treatment efficacy, health and chemical concerns, cost-benefits and maintenance protocol of a GW treatment system as well as the effect of irrigation with GW on crop yield. Therefore, a decentralized homemade GW treatment system was installed in a newly constructed house in Muscat, Oman and studied over a 2-year period. The treated GW was found to be suitable for irrigation as per Omani standards. GW when mixed with kitchen effluent substituted the use of nutrient supplements for plants and did not show any harmful chemical or biological contamination. The capital cost of the system was around US $980, and the annual operating cost was US $78 with annual income and savings from the system being around US $572 indicating a payback period of nearly 2 years. It was found that the system required simple but regular maintenance particularly cleaning of the top layer of the filter. It can be concluded from this study that such a GW system should be technically, economically and environmentally feasible in Oman. Also, wider acceptance by the general public to the idea of GW reuse will help in mitigating the water shortage problem of the country to some extent.
- Full Text:
- Date Issued: 2017
- Authors: Al-Ismaili, Abdulrahim M , Ahmed, Mushtaque , Al-Busaidi, Ahmed , Al-Adawi, Seif , Tandlich, Roman , Al-Amri, Mohammed
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76048 , vital:30497 , https://doi.org/10.1007/s11356-017-8963-z
- Description: The use of treated grey water (GW) for home gardens, peri-urban agriculture and landscaping is becoming popular in many water stressed countries such as Oman. This study aims to investigate the treatment efficacy, health and chemical concerns, cost-benefits and maintenance protocol of a GW treatment system as well as the effect of irrigation with GW on crop yield. Therefore, a decentralized homemade GW treatment system was installed in a newly constructed house in Muscat, Oman and studied over a 2-year period. The treated GW was found to be suitable for irrigation as per Omani standards. GW when mixed with kitchen effluent substituted the use of nutrient supplements for plants and did not show any harmful chemical or biological contamination. The capital cost of the system was around US $980, and the annual operating cost was US $78 with annual income and savings from the system being around US $572 indicating a payback period of nearly 2 years. It was found that the system required simple but regular maintenance particularly cleaning of the top layer of the filter. It can be concluded from this study that such a GW system should be technically, economically and environmentally feasible in Oman. Also, wider acceptance by the general public to the idea of GW reuse will help in mitigating the water shortage problem of the country to some extent.
- Full Text:
- Date Issued: 2017
Framing of transitional pedagogic practices in the sciences: enabling access
- Authors: Ellery, Karen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66381 , vital:28942 , https://doi.org/10.1080/13562517.2017.1319812
- Description: publisher version , Educational literature shows that students from working-class backgrounds are significantly less likely to persist to completion in higher education than middle-class students. This paper draws theoretically and analytically on Bernstein’s ([1990. Class, Codes and Control, Volume IV: The Structuring of Pedagogic Discourse. London: Routledge; 2000. Pedagogy, Symbolic Control, and Identity: Theory, Research, Critique. Lanham: Rowman and Littlefield]) thesis that, through differential framing of pedagogic practices, the curriculum has capacity to accommodate all groups of students. Pedagogic practices in both a science foundation course and four first-year mainstream science courses in a higher education institution in the South African context are examined. Whilst the foundation course exhibits modalities that generally favour access, the mainstream courses have some modalities that appear to be constraining. It is argued from a social justice perspective that holistic curriculum transformations that better enable epistemic transitions are an urgent imperative, and that consideration of differential framing of pedagogic modalities offer a close-up empirical means of conceptualising such reforms.
- Full Text: false
- Date Issued: 2017
- Authors: Ellery, Karen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66381 , vital:28942 , https://doi.org/10.1080/13562517.2017.1319812
- Description: publisher version , Educational literature shows that students from working-class backgrounds are significantly less likely to persist to completion in higher education than middle-class students. This paper draws theoretically and analytically on Bernstein’s ([1990. Class, Codes and Control, Volume IV: The Structuring of Pedagogic Discourse. London: Routledge; 2000. Pedagogy, Symbolic Control, and Identity: Theory, Research, Critique. Lanham: Rowman and Littlefield]) thesis that, through differential framing of pedagogic practices, the curriculum has capacity to accommodate all groups of students. Pedagogic practices in both a science foundation course and four first-year mainstream science courses in a higher education institution in the South African context are examined. Whilst the foundation course exhibits modalities that generally favour access, the mainstream courses have some modalities that appear to be constraining. It is argued from a social justice perspective that holistic curriculum transformations that better enable epistemic transitions are an urgent imperative, and that consideration of differential framing of pedagogic modalities offer a close-up empirical means of conceptualising such reforms.
- Full Text: false
- Date Issued: 2017
Local people and conservation officials’ perceptions on relationships and conflicts in South African protected areas
- Thondhlana, Gladman, Cundill, Georgina
- Authors: Thondhlana, Gladman , Cundill, Georgina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68640 , vital:29300 , https://doi.org/10.1080/21513732.2017.1315742
- Description: Protected areas (PAs) are often conflict-ridden, but conflict resolution mechanisms are often constrained by little appreciation of the perceptions of the principal agents (PA managers and local communities) about such conflicts. Getting local people’s support in PA management efforts is considered important for achieving conservation and livelihood goals. Using data from 13 nature reserves in South Africa, this study explores the perceptions of reserve managers and local communities about their relationships and the existence and underlying causes of conflicts. The findings showed sharp contrasts in perceptions between reserve managers and local communities. Reserve managers generally perceived that there were no conflicts with local communities and that their relationship with them was positive while local communities thought otherwise, claiming conflicts were centred around restricted access to PAs, lack of benefits from PAs and communication problems. These findings have profound implications for conservation, especially considering the importance of getting local people’s support in PA management.
- Full Text:
- Date Issued: 2017
- Authors: Thondhlana, Gladman , Cundill, Georgina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68640 , vital:29300 , https://doi.org/10.1080/21513732.2017.1315742
- Description: Protected areas (PAs) are often conflict-ridden, but conflict resolution mechanisms are often constrained by little appreciation of the perceptions of the principal agents (PA managers and local communities) about such conflicts. Getting local people’s support in PA management efforts is considered important for achieving conservation and livelihood goals. Using data from 13 nature reserves in South Africa, this study explores the perceptions of reserve managers and local communities about their relationships and the existence and underlying causes of conflicts. The findings showed sharp contrasts in perceptions between reserve managers and local communities. Reserve managers generally perceived that there were no conflicts with local communities and that their relationship with them was positive while local communities thought otherwise, claiming conflicts were centred around restricted access to PAs, lack of benefits from PAs and communication problems. These findings have profound implications for conservation, especially considering the importance of getting local people’s support in PA management.
- Full Text:
- Date Issued: 2017
New morphological information on, and species of placoderm fish Africanaspis (Arthrodira, Placodermi) from the Late Devonian of South Africa
- Gess, Robert W, Trinajstic, Kate M
- Authors: Gess, Robert W , Trinajstic, Kate M
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72701 , vital:30101 , https://doi.org/10.1371/journal.pone.0173169
- Description: Here we present a new species of placoderm fish, Africanaspis edmountaini sp. nov., and redescribe Africanaspis doryssa on the basis of new material collected from the type locality of Africanaspis. The new material includes the first head shields of Africanaspis doryssa in addition to soft anatomy for both taxa. Hitherto Africanaspis was entirely described from trunk armour and no record of body and fin outlines had been recorded. In addition the first record of embryonic and juvenile specimens of Africanaspis doryssa is presented and provides a growth series from presumed hatchlings to presumed adults. The presence of a greater number of juveniles compared to adults indicates that the Waterloo Farm fossil site in South Africa represents the first nursery site of arthrodire placoderms known from a cold water environment. The preservation of an ontogenetic series demonstrates that variation within the earlier known sample, initially considered to have resulted from ontogenetic change, instead indicates the presence of a second, less common species Africanaspis edmountaini sp. nov. There is some faunal overlap between the Waterloo Farm fossil site and faunas described from Strud in Belgium and Red Hill, Pennsylvania, in north America, supporting the concept of a more cosmopolitan vertebrate fauna in the Famennian than earlier in the Devonian.
- Full Text:
- Date Issued: 2017
- Authors: Gess, Robert W , Trinajstic, Kate M
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72701 , vital:30101 , https://doi.org/10.1371/journal.pone.0173169
- Description: Here we present a new species of placoderm fish, Africanaspis edmountaini sp. nov., and redescribe Africanaspis doryssa on the basis of new material collected from the type locality of Africanaspis. The new material includes the first head shields of Africanaspis doryssa in addition to soft anatomy for both taxa. Hitherto Africanaspis was entirely described from trunk armour and no record of body and fin outlines had been recorded. In addition the first record of embryonic and juvenile specimens of Africanaspis doryssa is presented and provides a growth series from presumed hatchlings to presumed adults. The presence of a greater number of juveniles compared to adults indicates that the Waterloo Farm fossil site in South Africa represents the first nursery site of arthrodire placoderms known from a cold water environment. The preservation of an ontogenetic series demonstrates that variation within the earlier known sample, initially considered to have resulted from ontogenetic change, instead indicates the presence of a second, less common species Africanaspis edmountaini sp. nov. There is some faunal overlap between the Waterloo Farm fossil site and faunas described from Strud in Belgium and Red Hill, Pennsylvania, in north America, supporting the concept of a more cosmopolitan vertebrate fauna in the Famennian than earlier in the Devonian.
- Full Text:
- Date Issued: 2017
Nocturnal oviposition behavior of blowflies (Diptera: Calliphoridae) in the southern hemisphere (South Africa and Australia) and its forensic implications:
- Williams, Kirstin A, Wallman, James F, Lessard, Bryan D, Kavazos, Christopher R J, Mazungula, D Nkosinathi, Villet, Martin H
- Authors: Williams, Kirstin A , Wallman, James F , Lessard, Bryan D , Kavazos, Christopher R J , Mazungula, D Nkosinathi , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140832 , vital:37922 , DOI: 10.1007/s12024-017-9861-x
- Description: Published research has offered contradictory evidence of the occurrence of nocturnal oviposition by carrion-breeding blowflies, a behavior that can affect the interpretation of forensic estimates of a minimum post mortem interval (minPMI) by up to 12 hours, depending on latitude and season. The majority of published studies are from the northern hemisphere. Field experiments were conducted in South Africa and Australia that extend observations to species of the southern hemisphere. Various vertebrate carrion was exposed at night in summer under different lunar phases and/or artificial lighting, and in woodland and pasture areas. Three laboratory experiments were also conducted. No nocturnal oviposition occurred outdoors in Berry, Australia, but Lucilia cuprina, Lucilia sericata and Chrysomya megacephala laid eggs outdoors at night in Grahamstown and Durban, South Africa. In laboratory experiments L. sericata, L. cuprina, Chrysomya chloropyga and Chrysomya putoria laid eggs and Calliphora augur deposited larvae under nocturnal conditions.
- Full Text:
- Date Issued: 2017
- Authors: Williams, Kirstin A , Wallman, James F , Lessard, Bryan D , Kavazos, Christopher R J , Mazungula, D Nkosinathi , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140832 , vital:37922 , DOI: 10.1007/s12024-017-9861-x
- Description: Published research has offered contradictory evidence of the occurrence of nocturnal oviposition by carrion-breeding blowflies, a behavior that can affect the interpretation of forensic estimates of a minimum post mortem interval (minPMI) by up to 12 hours, depending on latitude and season. The majority of published studies are from the northern hemisphere. Field experiments were conducted in South Africa and Australia that extend observations to species of the southern hemisphere. Various vertebrate carrion was exposed at night in summer under different lunar phases and/or artificial lighting, and in woodland and pasture areas. Three laboratory experiments were also conducted. No nocturnal oviposition occurred outdoors in Berry, Australia, but Lucilia cuprina, Lucilia sericata and Chrysomya megacephala laid eggs outdoors at night in Grahamstown and Durban, South Africa. In laboratory experiments L. sericata, L. cuprina, Chrysomya chloropyga and Chrysomya putoria laid eggs and Calliphora augur deposited larvae under nocturnal conditions.
- Full Text:
- Date Issued: 2017
Oldest known naiaditid bivalve from the high-latitude Late Devonian (Famennian) of South Africa offers clues to survival strategies following the Hangenberg mass extinction
- Scholze, Frank, Gess, Robert W
- Authors: Scholze, Frank , Gess, Robert W
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73921 , vital:30241 , https://doi.org/10.1016/j.palaeo.2017.01.018
- Description: A phased mass extinction event (which culminated in the Hangenberg event) marked the end of the Devonian period and had a significant impact on the palaeoecology and faunal diversity of vertebrate and invertebrate communities. In the present study the taxonomy of bivalves from the Waterloo Farm lagerstätte of the Upper Devonian, Famennian, Witpoort Formation (Witteberg Group, Cape Supergroup) was studied and compared with known Carboniferous examples. For the first time, Devonian bivalves of the Naiaditidae are described from a high-latitude palaeogeographic setting of Gondwana. The presented data suggests a high-latitude origin for post-Hangenberg event Naiaditidae, found at lower latitudes during the Early Carboniferous. This may have resulted from migration to lower latitudes in response to reduced global temperatures, which were associated with climatic perturbation at the time of the Hangenberg event, and which persisted into the Early Carboniferous. Taxa that were adapted to temperature ranges existing at high latitudes during the Late Devonian are likely to have followed these temperature ranges towards lower latitudes with decreasing global temperatures. Here they may have occupied free ecospace available in the aftermath of the Late Devonian extinction event.
- Full Text:
- Date Issued: 2017
- Authors: Scholze, Frank , Gess, Robert W
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73921 , vital:30241 , https://doi.org/10.1016/j.palaeo.2017.01.018
- Description: A phased mass extinction event (which culminated in the Hangenberg event) marked the end of the Devonian period and had a significant impact on the palaeoecology and faunal diversity of vertebrate and invertebrate communities. In the present study the taxonomy of bivalves from the Waterloo Farm lagerstätte of the Upper Devonian, Famennian, Witpoort Formation (Witteberg Group, Cape Supergroup) was studied and compared with known Carboniferous examples. For the first time, Devonian bivalves of the Naiaditidae are described from a high-latitude palaeogeographic setting of Gondwana. The presented data suggests a high-latitude origin for post-Hangenberg event Naiaditidae, found at lower latitudes during the Early Carboniferous. This may have resulted from migration to lower latitudes in response to reduced global temperatures, which were associated with climatic perturbation at the time of the Hangenberg event, and which persisted into the Early Carboniferous. Taxa that were adapted to temperature ranges existing at high latitudes during the Late Devonian are likely to have followed these temperature ranges towards lower latitudes with decreasing global temperatures. Here they may have occupied free ecospace available in the aftermath of the Late Devonian extinction event.
- Full Text:
- Date Issued: 2017
On the sensitivity of thermally and optically stimulated luminescence of α-Al2O3: C and α-Al2O3: C, Mg
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119803 , vital:34784 , https://doi.org/10.1016/j.radmeas.2017.03.006
- Description: The luminescence sensitivity of α-Al2O3:C and α-Al2O3:C, Mg is of interest because of the contemporary use of these materials in dosimetry related applications. We report investigations concerning the change in sensitivity of thermoluminescence (TL) and optically stimulated luminescence (OSL) from α-Al2O3:C and α-Al2O3:C, Mg with re-use. The study was carried out on a set of un-annealed samples and others annealed at 700 and 900 °C. The TL and OSL sensitivity in α-Al2O3:C and α-Al2O3:C, Mg was found to increase with sample re-use whether the intensity was monitored as peak area or peak height for the main TL peak or, in the case of OSL, as the maximum intensity or the area under a decay curve. The fractional increase in area under either the main TL peak or the OSL decay curve exceeds that of the TL peak height or maximum OSL intensity when samples are re-used. However, when un-annealed samples are used, any increase in TL peak height or peak area per measurement is less than observed in annealed samples. It is also interesting to note that the change in maximum OSL intensity or OSL area is minimal for samples annealed at 900 °C. In general, the TL sensitivity in α-Al2O3:C increases more than that in α-Al2O3:C, Mg with re-use. On the other hand, the OSL sensitivity in α-Al2O3:C, Mg increases more than that in α-Al2O3:C with re-use. These findings suggest that it is advisable to take into account the fractional increase in sensitivity per measurement when one uses α-Al2O3:C as a TL dosimeter and α-Al2O3:C, Mg as an OSL dosimeter.
- Full Text: false
- Date Issued: 2017
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119803 , vital:34784 , https://doi.org/10.1016/j.radmeas.2017.03.006
- Description: The luminescence sensitivity of α-Al2O3:C and α-Al2O3:C, Mg is of interest because of the contemporary use of these materials in dosimetry related applications. We report investigations concerning the change in sensitivity of thermoluminescence (TL) and optically stimulated luminescence (OSL) from α-Al2O3:C and α-Al2O3:C, Mg with re-use. The study was carried out on a set of un-annealed samples and others annealed at 700 and 900 °C. The TL and OSL sensitivity in α-Al2O3:C and α-Al2O3:C, Mg was found to increase with sample re-use whether the intensity was monitored as peak area or peak height for the main TL peak or, in the case of OSL, as the maximum intensity or the area under a decay curve. The fractional increase in area under either the main TL peak or the OSL decay curve exceeds that of the TL peak height or maximum OSL intensity when samples are re-used. However, when un-annealed samples are used, any increase in TL peak height or peak area per measurement is less than observed in annealed samples. It is also interesting to note that the change in maximum OSL intensity or OSL area is minimal for samples annealed at 900 °C. In general, the TL sensitivity in α-Al2O3:C increases more than that in α-Al2O3:C, Mg with re-use. On the other hand, the OSL sensitivity in α-Al2O3:C, Mg increases more than that in α-Al2O3:C with re-use. These findings suggest that it is advisable to take into account the fractional increase in sensitivity per measurement when one uses α-Al2O3:C as a TL dosimeter and α-Al2O3:C, Mg as an OSL dosimeter.
- Full Text: false
- Date Issued: 2017
Stranded Action: Musa N Nxumalo’s ’16 Shots’
- Authors: Lila, Philiswa
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147115 , vital:38594 , https://artthrob.co.za/2017/05/23/stranded-action-musa-n-nxumalos-16-shots/
- Description: Musa Nxumalo’s exhibition ‘16 Shots’ at SMAC Johannesburg, reveals moments of particular and familiar events. It comprises a selection of sixteen black and white photographs focusing on #feesmustfall protest, youth parties, objects of still life and portraits of individuals. At face value, the images fall into the genre of documentary, reportage, of less excitement visually but meaningful as photo essays of relations between political and social matters of youth.
- Full Text:
- Date Issued: 2017
- Authors: Lila, Philiswa
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147115 , vital:38594 , https://artthrob.co.za/2017/05/23/stranded-action-musa-n-nxumalos-16-shots/
- Description: Musa Nxumalo’s exhibition ‘16 Shots’ at SMAC Johannesburg, reveals moments of particular and familiar events. It comprises a selection of sixteen black and white photographs focusing on #feesmustfall protest, youth parties, objects of still life and portraits of individuals. At face value, the images fall into the genre of documentary, reportage, of less excitement visually but meaningful as photo essays of relations between political and social matters of youth.
- Full Text:
- Date Issued: 2017
The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al2O3: C
- Nyirenda, Angel N, Chithambo, Makaiko L
- Authors: Nyirenda, Angel N , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119818 , vital:34786 , https://doi.org/10.1016/j.nimb.2017.02.077
- Description: It is known that when α-Al2O3:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al2O3:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450–650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.
- Full Text: false
- Date Issued: 2017
- Authors: Nyirenda, Angel N , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119818 , vital:34786 , https://doi.org/10.1016/j.nimb.2017.02.077
- Description: It is known that when α-Al2O3:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al2O3:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450–650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.
- Full Text: false
- Date Issued: 2017
The thin edge of the wedge: ukuthwala, alienation and consent
- Mwambene, Lea, Kruuse, Helen
- Authors: Mwambene, Lea , Kruuse, Helen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129165 , vital:36226 , https://doi.org/10.1080/02587203.2017.1303902
- Description: Ukuthwala, a mock abduction of a girl for the purpose of a customary marriage, has been subject to debate at both local and national level. This debate culminated into a South African Law Reform Commission Report on the practice of ukuthwala. However, the case of Jezile v S brings theory into reality, putting in stark relief the issues that surround this custom in a constitutional democracy. The Jezile case highlights the disjuncture between communities’ lived realities and the constitutional imperatives of the right to practice one’s culture, as well as the rights to equality and dignity, specifically for women and the girl child in the context of ukuthwala. Based on field research conducted in September 2015 and April 2016 in Engcobo (where the ukuthwala was alleged to take place in Jezile), this article sets out the community’s views in the aftermath of the case. Highlighting the alienation of the community from the law, and the complexities in understanding consent, the article posits that much more needs to be done from the ‘bottom up’ to ensure gender equality and protection of the girl child from harm.
- Full Text:
- Date Issued: 2017
- Authors: Mwambene, Lea , Kruuse, Helen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129165 , vital:36226 , https://doi.org/10.1080/02587203.2017.1303902
- Description: Ukuthwala, a mock abduction of a girl for the purpose of a customary marriage, has been subject to debate at both local and national level. This debate culminated into a South African Law Reform Commission Report on the practice of ukuthwala. However, the case of Jezile v S brings theory into reality, putting in stark relief the issues that surround this custom in a constitutional democracy. The Jezile case highlights the disjuncture between communities’ lived realities and the constitutional imperatives of the right to practice one’s culture, as well as the rights to equality and dignity, specifically for women and the girl child in the context of ukuthwala. Based on field research conducted in September 2015 and April 2016 in Engcobo (where the ukuthwala was alleged to take place in Jezile), this article sets out the community’s views in the aftermath of the case. Highlighting the alienation of the community from the law, and the complexities in understanding consent, the article posits that much more needs to be done from the ‘bottom up’ to ensure gender equality and protection of the girl child from harm.
- Full Text:
- Date Issued: 2017
Keeping it in the family: coevolution of latrunculid sponges and their dominant bacterial symbionts
- Matcher, Gwynneth F, Waterworth, Samantha C, Walmsley, Tara A, Matsatsa, Tendayi, Parker-Nance, Shirley, Davies-Coleman, Michael T, Dorrington, Rosemary A
- Authors: Matcher, Gwynneth F , Waterworth, Samantha C , Walmsley, Tara A , Matsatsa, Tendayi , Parker-Nance, Shirley , Davies-Coleman, Michael T , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65603 , vital:28818 , https://doi.org/10.1002/mbo3.417
- Description: publisher version , The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast. The bacterial communities of all seven sponge species were dominated by a single Betaproteobacterium operational taxonomic unit (OTU0.03), while a second OTU0.03 was dominant in the Mycale sp. The Betaproteobacteria OTUs from the different latrunculid sponges are closely related and their phylogenetic relationship follows that of their hosts. We propose that the latrunculid Betaproteobacteria OTUs are members of a specialized group of sponge symbionts that may have coevolved with their hosts. A single dominant Spirochaetae OTU0.03 was present in the Tsitsikamma and Cyclacanthia sponge species, but absent from the Latrunculia and Mycale sponges. This study sheds new light on the interactions between latrunculid sponges and their bacterial communities and may point to the potential involvement of dominant symbionts in the biosynthesis of the bioactive secondary metabolites. , This research was supported by a SARChI grant from the South African National Research Foundation (NRF, GUN: 87583) and the Rhodes University Sandisa Imbewu Programme. S. C. W. was supported by an NRF Innovation PhD Scholarship and a Rhodes University Henderson PhD Scholarship. T. A. W. was supported by PhD Fellowships from the NRF and the German Academic Exchange Service (DAAD)
- Full Text:
- Date Issued: 2016
- Authors: Matcher, Gwynneth F , Waterworth, Samantha C , Walmsley, Tara A , Matsatsa, Tendayi , Parker-Nance, Shirley , Davies-Coleman, Michael T , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65603 , vital:28818 , https://doi.org/10.1002/mbo3.417
- Description: publisher version , The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast. The bacterial communities of all seven sponge species were dominated by a single Betaproteobacterium operational taxonomic unit (OTU0.03), while a second OTU0.03 was dominant in the Mycale sp. The Betaproteobacteria OTUs from the different latrunculid sponges are closely related and their phylogenetic relationship follows that of their hosts. We propose that the latrunculid Betaproteobacteria OTUs are members of a specialized group of sponge symbionts that may have coevolved with their hosts. A single dominant Spirochaetae OTU0.03 was present in the Tsitsikamma and Cyclacanthia sponge species, but absent from the Latrunculia and Mycale sponges. This study sheds new light on the interactions between latrunculid sponges and their bacterial communities and may point to the potential involvement of dominant symbionts in the biosynthesis of the bioactive secondary metabolites. , This research was supported by a SARChI grant from the South African National Research Foundation (NRF, GUN: 87583) and the Rhodes University Sandisa Imbewu Programme. S. C. W. was supported by an NRF Innovation PhD Scholarship and a Rhodes University Henderson PhD Scholarship. T. A. W. was supported by PhD Fellowships from the NRF and the German Academic Exchange Service (DAAD)
- Full Text:
- Date Issued: 2016
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