Invasion of a South African Anguilla mossambica (Anguillidae) population by the alien gill worm Pseudodactylogyrus anguillae (Monogenea)
- Parker, Denham, Weyl, Olaf L F, Taraschewski, Horst
- Authors: Parker, Denham , Weyl, Olaf L F , Taraschewski, Horst
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443367 , vital:74111 , https://hdl.handle.net/10520/EJC18196
- Description: The parasitic gill monogenean Pseudodactylogyrus anguillae is alien to Africa. In an investigation of 227 longfin eel, Anguilla mossambica, and 26 mottled eel, Anguilla marmorata, sampled from four river systems in the Eastern Cape, South Africa, this parasite was only present on the gills of A. mossambica sampled from the Great Fish River system. In the Great Fish River, it infected 73.2% of the sampled population at a mean intensity of 63.8 ± 34.3 parasites per fish. High prevalence and intensity are indicative of a well-established alien invasive parasitic species. Results showing the absence of P. anguillae from the co-occurring but less abundant A. marmorata indicate that this species may be less susceptible to P. anguillae infection.
- Full Text:
- Authors: Parker, Denham , Weyl, Olaf L F , Taraschewski, Horst
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443367 , vital:74111 , https://hdl.handle.net/10520/EJC18196
- Description: The parasitic gill monogenean Pseudodactylogyrus anguillae is alien to Africa. In an investigation of 227 longfin eel, Anguilla mossambica, and 26 mottled eel, Anguilla marmorata, sampled from four river systems in the Eastern Cape, South Africa, this parasite was only present on the gills of A. mossambica sampled from the Great Fish River system. In the Great Fish River, it infected 73.2% of the sampled population at a mean intensity of 63.8 ± 34.3 parasites per fish. High prevalence and intensity are indicative of a well-established alien invasive parasitic species. Results showing the absence of P. anguillae from the co-occurring but less abundant A. marmorata indicate that this species may be less susceptible to P. anguillae infection.
- Full Text:
Invasive alien freshwater fishes in the Wilderness Lakes System, a wetland of international importance in the Western Cape Province, South Africa
- Olds, Alexis A, Smith, M K S, Weyl, Olaf L F, Russell, I A
- Authors: Olds, Alexis A , Smith, M K S , Weyl, Olaf L F , Russell, I A
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446879 , vital:74567 , https://doi.org/10.1080/15627020.2011.11407491
- Description: The Wilderness Lakes System incorporates a RAMSAR listed wetland. Previous ichthyological surveys reported three invasive freshwater fishes; Oreochromis mossambicus (Mozambique tilapia), Gambusia affinis (mosquitofish) and Micropterus salmoides (largemouth bass) from this system. To assess the status of these alien fishes, the fish assemblages in the lakes system were sampled with seine nets and fyke nets in 2009 and 2010. A total of 87 893 fish comprising 16 species were caught. In addition to confirming the persistence of O. mossambicus and G. affinis in the system, the current study also reports the presence of a new invader, Cyprinus carpio (common carp). M. salmoides were absent from 2009 and 2010 samples.
- Full Text:
- Authors: Olds, Alexis A , Smith, M K S , Weyl, Olaf L F , Russell, I A
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446879 , vital:74567 , https://doi.org/10.1080/15627020.2011.11407491
- Description: The Wilderness Lakes System incorporates a RAMSAR listed wetland. Previous ichthyological surveys reported three invasive freshwater fishes; Oreochromis mossambicus (Mozambique tilapia), Gambusia affinis (mosquitofish) and Micropterus salmoides (largemouth bass) from this system. To assess the status of these alien fishes, the fish assemblages in the lakes system were sampled with seine nets and fyke nets in 2009 and 2010. A total of 87 893 fish comprising 16 species were caught. In addition to confirming the persistence of O. mossambicus and G. affinis in the system, the current study also reports the presence of a new invader, Cyprinus carpio (common carp). M. salmoides were absent from 2009 and 2010 samples.
- Full Text:
Investigation of homogeneous photosensitized oxidation activities of palladium and platinum octasubstituted phthalocyanines
- Ogunbayo, Taofeek B, Antunes, Edith M, Nyokong, Tebello
- Authors: Ogunbayo, Taofeek B , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248394 , vital:51682 , xlink:href="https://doi.org/10.1016/j.molcata.2010.11.008"
- Description: Photosensitized oxidation of 4-nitrophenol was studied in organic solutions with seven octasubstituted thio and aryloxy palladium and platinum phthalocyanines acting as photosensitizers. Kinetic studies conducted also showed that the complexes have different singlet oxygen quenching constants with direct implication on the quantum yield of photodegradation of 4-nitrophenol (Φ4-NP). Palladium analogues gave better results than the platinum analogues in terms of Φ4-NP with palladium-(dodecylthio)phthalocyanine giving the highest yield of 1.8 × 10−3. Gas chromatography (GC) and liquid chromatography connected to a mass spectrometer (LC–MS) were used to confirm the photodegradation products which were hydroquinone and 1,4-benzoquinone.
- Full Text:
- Authors: Ogunbayo, Taofeek B , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248394 , vital:51682 , xlink:href="https://doi.org/10.1016/j.molcata.2010.11.008"
- Description: Photosensitized oxidation of 4-nitrophenol was studied in organic solutions with seven octasubstituted thio and aryloxy palladium and platinum phthalocyanines acting as photosensitizers. Kinetic studies conducted also showed that the complexes have different singlet oxygen quenching constants with direct implication on the quantum yield of photodegradation of 4-nitrophenol (Φ4-NP). Palladium analogues gave better results than the platinum analogues in terms of Φ4-NP with palladium-(dodecylthio)phthalocyanine giving the highest yield of 1.8 × 10−3. Gas chromatography (GC) and liquid chromatography connected to a mass spectrometer (LC–MS) were used to confirm the photodegradation products which were hydroquinone and 1,4-benzoquinone.
- Full Text:
JM Coetzee's Disgrace: a reader's guide, and: JM Coetzee's austerities
- Authors: Marais, Mike
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144231 , vital:38323 , DOI: 10.2979/reseafrilite.42.4.135
- Description: Like all of the other publications in the series of which it forms a part, Andrew van der Vlies's Disgrace: A Reader's Guide conforms to a set format: a preface, followed by biographical information on the novelist and the context in which he or she wrote the text concerned, and then a longer section comprising a paraphrase and discussion of the work and its reception, together with suggestions for further reading. Despite these structural constraints, van der Vlies provides a very fine introduction to Disgrace in this volume. Readers will find especially insightful his treatment of Coetzee's preoccupation with alterity, and the responsibility, both ethical and aesthetic, that such otherness exacts. One very slight criticism I have of the monograph is that it could have contained more references to discussions of Coetzee's use of narrative point of view in its list of recommended reading. (James Meffan and Kim Worthington's examination of the ambivalent relationship between David Lurie and the narrator's voice comes to mind here, for instance.) Having said this, however, I have little doubt that van der Vlies's guide will prove a useful and comprehensive introduction to Disgrace in university programs.
- Full Text:
- Authors: Marais, Mike
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144231 , vital:38323 , DOI: 10.2979/reseafrilite.42.4.135
- Description: Like all of the other publications in the series of which it forms a part, Andrew van der Vlies's Disgrace: A Reader's Guide conforms to a set format: a preface, followed by biographical information on the novelist and the context in which he or she wrote the text concerned, and then a longer section comprising a paraphrase and discussion of the work and its reception, together with suggestions for further reading. Despite these structural constraints, van der Vlies provides a very fine introduction to Disgrace in this volume. Readers will find especially insightful his treatment of Coetzee's preoccupation with alterity, and the responsibility, both ethical and aesthetic, that such otherness exacts. One very slight criticism I have of the monograph is that it could have contained more references to discussions of Coetzee's use of narrative point of view in its list of recommended reading. (James Meffan and Kim Worthington's examination of the ambivalent relationship between David Lurie and the narrator's voice comes to mind here, for instance.) Having said this, however, I have little doubt that van der Vlies's guide will prove a useful and comprehensive introduction to Disgrace in university programs.
- Full Text:
Knowing, acting and being: Epistemological and ontological access in a Science Extended Studies course
- Authors: Ellery, Karen
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69471 , vital:29540 , https://hdl.handle.net/10520/EJC37737
- Description: Gross participation and throughput rates in higher education institutions in South Africa indicate an inequitable and poorly functioning system. This interpretive study argues for an approach that enhances epistemological and ontological access and examines how an intervention that includes an overt approach in dealing with the nature of science, coupled with student involvement in an independent research project in a Science Extended Studies course, can enhance such access to higher education study. Analysis of project outcomes and student critical reflections indicated access to scientific and academic Discourses was enhanced through: developing improved procedural and conceptual scientific knowledge; meaningful engagement with the language, norms and conventions of the Discourse; integrating everyday knowledge into more abstract scientific knowledge; awareness of the process of validation of scientific knowledge, of the limitations of science, and of the impact of science on society; and transforming personally by developing scientific discursive identity and a sense of belonging. In conclusion, it is argued that curriculum interventions that focus on epistemological and ontological aspects of learning could appropriately be used throughout the higher education science sector.
- Full Text:
- Authors: Ellery, Karen
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69471 , vital:29540 , https://hdl.handle.net/10520/EJC37737
- Description: Gross participation and throughput rates in higher education institutions in South Africa indicate an inequitable and poorly functioning system. This interpretive study argues for an approach that enhances epistemological and ontological access and examines how an intervention that includes an overt approach in dealing with the nature of science, coupled with student involvement in an independent research project in a Science Extended Studies course, can enhance such access to higher education study. Analysis of project outcomes and student critical reflections indicated access to scientific and academic Discourses was enhanced through: developing improved procedural and conceptual scientific knowledge; meaningful engagement with the language, norms and conventions of the Discourse; integrating everyday knowledge into more abstract scientific knowledge; awareness of the process of validation of scientific knowledge, of the limitations of science, and of the impact of science on society; and transforming personally by developing scientific discursive identity and a sense of belonging. In conclusion, it is argued that curriculum interventions that focus on epistemological and ontological aspects of learning could appropriately be used throughout the higher education science sector.
- Full Text:
Learning to squander: making meaningful connections in the infinite text of world culture
- Authors: Jamal, Ashraf
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147391 , vital:38632 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC45816
- Description: In this article on South African visual art I fix my sight on a global interhuman and aesthetic sphere in which region/nation/transnation merge to produce a cultural economy that overlaps and cannot be satisfactorily grasped according to a centre-periphery model. This eschewal of existing binary models also means a reconceptualisation of the liminal as an in-between space in a fixed divide. Currently it is not only the margin that is indeterminate, but the infinite text of the global cultural economy within which visual art plays its part.
- Full Text:
- Authors: Jamal, Ashraf
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147391 , vital:38632 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC45816
- Description: In this article on South African visual art I fix my sight on a global interhuman and aesthetic sphere in which region/nation/transnation merge to produce a cultural economy that overlaps and cannot be satisfactorily grasped according to a centre-periphery model. This eschewal of existing binary models also means a reconceptualisation of the liminal as an in-between space in a fixed divide. Currently it is not only the margin that is indeterminate, but the infinite text of the global cultural economy within which visual art plays its part.
- Full Text:
Life history and population dynamics of invasive common carp, Cyprinus carpio, within a large turbid African impoundment
- Winker, A Henning, Weyl, Olaf L F, Booth, Anthony J, Ellender, Bruce R
- Authors: Winker, A Henning , Weyl, Olaf L F , Booth, Anthony J , Ellender, Bruce R
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124898 , vital:35708 , https://doi.10.1071/MF11054
- Description: Common carp (Cyprinus carpio) is one of the world’s most widely introduced and established freshwater fishes (Casal 2006). The species is considered to be one of the eight most invasive freshwater fishes (Lowe et al. 2000) and worldwide, it accounts for most of the records of successful establishments and adverse ecological effects (Casal 2006; Kulhanek et al. 2011). This invasive success suggests that feral C. carpio is equipped with a set of adaptable life history attributes that allow it to successfully colonise a wide range of habitats (Koehn 2004; Zambrano et al. 2006; Britton et al. 2007). Where feral C. carpio occurs in high densities, it is often perceived as an invasive pest species (Sivakumaran et al. 2003; Brown and Walker 2004; Koehn 2004) because it can have severe impacts on habitat heterogeneity and biodiversity by increasing water turbidity through its bottom feeding behaviour, increasing nutrient availability, decreasing benthic and macrophyte density and diversity, altering zooplankton assemblages and decreasing endemic fish abundance (Zambrano et al. 2001; Khan 2003; Kulhanek et al. 2011). Within south-east Australia, for example, C. carpio comprises the largest proportion of the ichthyobiomass in the continent’s largest river system – the Murray–Darling Basin (Gehrke et al. 1995). As a consequence, serious concerns about its threat to endemic freshwater species (Koehn 2004) have prompted several of the most recent investigations into its life history (e.g. Sivakumaran et al. 2003; Smith and Walker 2004; Brown et al. 2005). Other potential threats posed also include competition with indigenous species and the spread of diseases and parasites (Dudgeon et al. 2006). In South Africa, for example, Asian tapeworm Bothriocephalus acheilognathi is now widely distributed in seven river systems and has infected eight novel cyprinid hosts due to the translocation of infected by C. carpio from a centralized aquaculture facility (Stadtlander et al. 2011).
- Full Text:
- Authors: Winker, A Henning , Weyl, Olaf L F , Booth, Anthony J , Ellender, Bruce R
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124898 , vital:35708 , https://doi.10.1071/MF11054
- Description: Common carp (Cyprinus carpio) is one of the world’s most widely introduced and established freshwater fishes (Casal 2006). The species is considered to be one of the eight most invasive freshwater fishes (Lowe et al. 2000) and worldwide, it accounts for most of the records of successful establishments and adverse ecological effects (Casal 2006; Kulhanek et al. 2011). This invasive success suggests that feral C. carpio is equipped with a set of adaptable life history attributes that allow it to successfully colonise a wide range of habitats (Koehn 2004; Zambrano et al. 2006; Britton et al. 2007). Where feral C. carpio occurs in high densities, it is often perceived as an invasive pest species (Sivakumaran et al. 2003; Brown and Walker 2004; Koehn 2004) because it can have severe impacts on habitat heterogeneity and biodiversity by increasing water turbidity through its bottom feeding behaviour, increasing nutrient availability, decreasing benthic and macrophyte density and diversity, altering zooplankton assemblages and decreasing endemic fish abundance (Zambrano et al. 2001; Khan 2003; Kulhanek et al. 2011). Within south-east Australia, for example, C. carpio comprises the largest proportion of the ichthyobiomass in the continent’s largest river system – the Murray–Darling Basin (Gehrke et al. 1995). As a consequence, serious concerns about its threat to endemic freshwater species (Koehn 2004) have prompted several of the most recent investigations into its life history (e.g. Sivakumaran et al. 2003; Smith and Walker 2004; Brown et al. 2005). Other potential threats posed also include competition with indigenous species and the spread of diseases and parasites (Dudgeon et al. 2006). In South Africa, for example, Asian tapeworm Bothriocephalus acheilognathi is now widely distributed in seven river systems and has infected eight novel cyprinid hosts due to the translocation of infected by C. carpio from a centralized aquaculture facility (Stadtlander et al. 2011).
- Full Text:
LTSP DNS round robin clusters: green technology access enablers for telecommunication services in marginalised communities
- Siebörger, Ingrid, Terzoli, Alfredo, Hodgkinson-Williams, Cheryl
- Authors: Siebörger, Ingrid , Terzoli, Alfredo , Hodgkinson-Williams, Cheryl
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428437 , vital:72511 , https://d1wqtxts1xzle7.cloudfront.net/75984640/177-libre.pdf?1639074275=andresponse-content-disposi-tion=inline%3B+filename%3DLTSP_DNS_Round_Robin_Clusters_Green_Tech.pdfandExpires=1714912779andSignature=Gmd52OTCvGmiKhiFiQH~rrfp6lSPbp7glndLPn7V4Jy5yt7lU-eToE4IPxr7lDQQOdUW348nkXIMgYHnXkWjWl7nYBM7hlluxJGd15oKbpifvTofHVVEB-kOLbz0caOrAodnS~eMHdebRQOumKSAHPGQkqem756vbw0KV7bhmFQ0TUN-vsVeBoH5ftfg7s355Oh9EZCQhZu~~P0AWzlSRnMTH~6vpj3EKvp7P4gy55oISZ~207VFFFZidb90aoP7JWehRYjRqn3Tk19A6nwm4o9U-wc9Dz1MrCy-YfbqOxdNulQh4bti2WI7DA6C3Q8TMCbtqnZskXQYsIzfEianS~gw__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Rural development is seen as a priority in South Africa; information and knowledge are key strategic resources for social and economic develop-ment. Information Communication Technologies (ICTs) are seen as im-portant tools in rural development, assisting in enabling change through economic development. In rural areas where ICT infrastructure is being expanded and deployed there is a need to provide appropriate technolo-gies that support sustainability and meet the needs of the local communi-ty. In this paper we argue that the use of Linux Terminal Server Project (LTSP) cluster servers are appropriate technologies for use in computer laboratory environments for relatively inexpensive access to technologies by schools and local communities in rural areas. Typically LTSP clusters are deployed when there is a need to support 100s or 1000s of comput-ers, however, we argue that by reusing recycled (older) desktop or server computers as cluster servers could lower the entry level costs of LTSP computing while maximising the use of available resources. The paper details the configuration of a Domain Name System (DNS) round robin cluster solution together with initial testing and results. It is suggested that LTSP cluster solutions, and the DNS round robin implementation, show promise for use in providing access technologies to rural communities and schools.
- Full Text:
- Authors: Siebörger, Ingrid , Terzoli, Alfredo , Hodgkinson-Williams, Cheryl
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428437 , vital:72511 , https://d1wqtxts1xzle7.cloudfront.net/75984640/177-libre.pdf?1639074275=andresponse-content-disposi-tion=inline%3B+filename%3DLTSP_DNS_Round_Robin_Clusters_Green_Tech.pdfandExpires=1714912779andSignature=Gmd52OTCvGmiKhiFiQH~rrfp6lSPbp7glndLPn7V4Jy5yt7lU-eToE4IPxr7lDQQOdUW348nkXIMgYHnXkWjWl7nYBM7hlluxJGd15oKbpifvTofHVVEB-kOLbz0caOrAodnS~eMHdebRQOumKSAHPGQkqem756vbw0KV7bhmFQ0TUN-vsVeBoH5ftfg7s355Oh9EZCQhZu~~P0AWzlSRnMTH~6vpj3EKvp7P4gy55oISZ~207VFFFZidb90aoP7JWehRYjRqn3Tk19A6nwm4o9U-wc9Dz1MrCy-YfbqOxdNulQh4bti2WI7DA6C3Q8TMCbtqnZskXQYsIzfEianS~gw__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Rural development is seen as a priority in South Africa; information and knowledge are key strategic resources for social and economic develop-ment. Information Communication Technologies (ICTs) are seen as im-portant tools in rural development, assisting in enabling change through economic development. In rural areas where ICT infrastructure is being expanded and deployed there is a need to provide appropriate technolo-gies that support sustainability and meet the needs of the local communi-ty. In this paper we argue that the use of Linux Terminal Server Project (LTSP) cluster servers are appropriate technologies for use in computer laboratory environments for relatively inexpensive access to technologies by schools and local communities in rural areas. Typically LTSP clusters are deployed when there is a need to support 100s or 1000s of comput-ers, however, we argue that by reusing recycled (older) desktop or server computers as cluster servers could lower the entry level costs of LTSP computing while maximising the use of available resources. The paper details the configuration of a Domain Name System (DNS) round robin cluster solution together with initial testing and results. It is suggested that LTSP cluster solutions, and the DNS round robin implementation, show promise for use in providing access technologies to rural communities and schools.
- Full Text:
Macrofaunal community structure in the littoral zone of a freshwater-deprived, permanently open Eastern Cape estuary
- Henninger, Tony O, Froneman, P William
- Authors: Henninger, Tony O , Froneman, P William
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443954 , vital:74174 , https://doi.org/10.1080/15627020.2011.11407500
- Description: Spatial patterns in the macrofauna community structure within four distinct zones of the permanently open, freshwater-deprived Kariega Estuary on the southeastern coastline of southern Africa were investigated in March–May 2010. The zones within the littoral zone comprised a band of Zostera capensis (Setchell) exposed at spring low tide and comprising Zone I; a band of mud or sand, lacking vegetation, corresponded to Zone II; stands of Spartina maritima (Curtis) formed Zone III and a belt of Sarcocornia perennis (Miller) constituted Zone IV.
- Full Text:
- Authors: Henninger, Tony O , Froneman, P William
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443954 , vital:74174 , https://doi.org/10.1080/15627020.2011.11407500
- Description: Spatial patterns in the macrofauna community structure within four distinct zones of the permanently open, freshwater-deprived Kariega Estuary on the southeastern coastline of southern Africa were investigated in March–May 2010. The zones within the littoral zone comprised a band of Zostera capensis (Setchell) exposed at spring low tide and comprising Zone I; a band of mud or sand, lacking vegetation, corresponded to Zone II; stands of Spartina maritima (Curtis) formed Zone III and a belt of Sarcocornia perennis (Miller) constituted Zone IV.
- Full Text:
Microelectrochemical patterning of gold surfaces using 4-azidobenzenediazonium and scanning electrochemical microscopy
- Coates, Megan, Cabet, Eva, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Coates, Megan , Cabet, Eva , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247926 , vital:51630 , xlink:href="https://doi.org/10.1016/j.elecom.2010.11.037"
- Description: This work describes for the first time the possibility of performing local micro electrochemical grafting of a gold substrate by 4-azidobenzenediazonium by SECM in a single and simple one step without complications from adsorption. The electrografted spots of diazonium were performed by positioning a Pt tip at a given distance above the gold substrate and the SECM was used in a three-electrode configuration (the Pt tip serving as the microanode) in acetonitrile containing 5 mM 4-azidobenzenediazonium and 0.1 M Bu4NBF4 during 10 ms. The dimensions of the derivatized areas of the substrates were finely tuned by using different experimental conditions (tip distance above the substrate, tip diameter, presence or absence of supporting electrolyte). The use of the azido-derivated diazonium molecule and these preliminary results open the gate to important applications and developments devoted to the local micro functionalization of electrodes by thin layers that allow the implementation of the emerging and attractive interfacial click reaction.
- Full Text:
- Authors: Coates, Megan , Cabet, Eva , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247926 , vital:51630 , xlink:href="https://doi.org/10.1016/j.elecom.2010.11.037"
- Description: This work describes for the first time the possibility of performing local micro electrochemical grafting of a gold substrate by 4-azidobenzenediazonium by SECM in a single and simple one step without complications from adsorption. The electrografted spots of diazonium were performed by positioning a Pt tip at a given distance above the gold substrate and the SECM was used in a three-electrode configuration (the Pt tip serving as the microanode) in acetonitrile containing 5 mM 4-azidobenzenediazonium and 0.1 M Bu4NBF4 during 10 ms. The dimensions of the derivatized areas of the substrates were finely tuned by using different experimental conditions (tip distance above the substrate, tip diameter, presence or absence of supporting electrolyte). The use of the azido-derivated diazonium molecule and these preliminary results open the gate to important applications and developments devoted to the local micro functionalization of electrodes by thin layers that allow the implementation of the emerging and attractive interfacial click reaction.
- Full Text:
Morphology and identification of first instars of African blow flies (Diptera: Calliphoridae) commonly of forensic importance
- Szpila, Krzysztof, Villet, Martin H
- Authors: Szpila, Krzysztof , Villet, Martin H
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442225 , vital:73968 , https://doi.org/10.1603/ME10238
- Description: Scanning electron microscopy images of the first instars of Calliphora croceipalpis Jaennicke, 1876; Chrysomya chloropyga (Wiedemann, 1818); Chrysomya marginalis (Wiedemann, 1830); and Chrysomya putoria (Wiedemann, 1830) (Diptera: Calliphoridae) are presented for the first time, and the following morphological structures are documented: pseudocephalon, antenna, maxillary palpus, facial mask, labial lobe, thoracic and abdominal spinulation, spiracular field, posterior spiracles, and anal pads. Light microscopy photographs and line illustrations are provided for the cephaloskeleton in lateral and ventral views, and the “ectostomal sclerite” and “chitinized teeth” of the cephaloskeleton are recognized as integral parts of the mouthhooks. New diagnostic features of the cephaloskeleton and the spinulation of the abdominal segments are described. These results allow refinement, clarification, and correction of earlier descriptions, which are reviewed. The relative taxonomic importance of various morphological characters of the first instars of necrophagous blow flies is discussed, and details of the cephaloskeleton and the spinulation of the abdominal segments are highlighted as the characters most useful for species identification. Finally, a key for identifying first instars of common African carrion blow flies is provided.
- Full Text:
- Authors: Szpila, Krzysztof , Villet, Martin H
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442225 , vital:73968 , https://doi.org/10.1603/ME10238
- Description: Scanning electron microscopy images of the first instars of Calliphora croceipalpis Jaennicke, 1876; Chrysomya chloropyga (Wiedemann, 1818); Chrysomya marginalis (Wiedemann, 1830); and Chrysomya putoria (Wiedemann, 1830) (Diptera: Calliphoridae) are presented for the first time, and the following morphological structures are documented: pseudocephalon, antenna, maxillary palpus, facial mask, labial lobe, thoracic and abdominal spinulation, spiracular field, posterior spiracles, and anal pads. Light microscopy photographs and line illustrations are provided for the cephaloskeleton in lateral and ventral views, and the “ectostomal sclerite” and “chitinized teeth” of the cephaloskeleton are recognized as integral parts of the mouthhooks. New diagnostic features of the cephaloskeleton and the spinulation of the abdominal segments are described. These results allow refinement, clarification, and correction of earlier descriptions, which are reviewed. The relative taxonomic importance of various morphological characters of the first instars of necrophagous blow flies is discussed, and details of the cephaloskeleton and the spinulation of the abdominal segments are highlighted as the characters most useful for species identification. Finally, a key for identifying first instars of common African carrion blow flies is provided.
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National case study : teacher professional development with an education for sustainable development focus in South Africa: development of a network, curriculum framework and resources for teacher education
- Authors: Lotz-Sisitka, Heila
- Date: 2011
- Subjects: Teachers -- Training of , Career development , Sustainable development -- South Africa
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59646 , vital:27634 , https://www.ajol.info/index.php/sajee/article/view/122242
- Description: This national case study reports on the development of a national network, curriculum framework and resources for teacher education, with specific focus on the inclusion of environment and sustainability, also known as education for sustainable development (ESD) in the South African teacher education system. It reviews and reports on the history of environment and sustainability education in teacher education, and from this, the national case study begins to conceptualise a new approach to environment and sustainability teacher education within a new curriculum policy environment, and a new teacher education and development policy environment. Action research case study methodology is used to document the first phase of the emergence of this network, and this report covers Phase 1 of the initiative, which covers formation of the network, review of previous practices, three conceptual development pilot studies undertaken in both in-service and pre-service teacher education environments and a piloting of a ‘Train the Trainers’ or ‘Educate the Teacher Educators’ programme, which complements and extends the actual teacher education and development (TED) programme under development. The study highlights critical insights of relevance to the shift to a content referenced curriculum in South Africa, and shows how the ‘knowledge mix’ which forms the foundation of the new Teacher Education Qualifications Framework can be engaged. It also highlights some features of the changing knowledge environment, and what dominant knowledge practices are in environment and sustainability-related teaching and teacher education practices, opening these up for further scrutiny. It raises concerns that dominant knowledge work, while integrating a range of forms of knowledge (as is expected of the teacher education system under the new policy), tends to be limited by content on problems and issues for raising awareness, and fails to develop deeper conceptual depth and understanding of environment and sustainability, as issues based knowledge dominates. Similarly, it fails to support social innovation as a response to environment and sustainability concerns, as awareness raising dominates in dominant knowledge work. The study provides a revised conceptual framework for the Teacher Development Network (TEDN) programme, with guidance on key elements necessary to take the programme forward in Phase 2.
- Full Text:
- Authors: Lotz-Sisitka, Heila
- Date: 2011
- Subjects: Teachers -- Training of , Career development , Sustainable development -- South Africa
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59646 , vital:27634 , https://www.ajol.info/index.php/sajee/article/view/122242
- Description: This national case study reports on the development of a national network, curriculum framework and resources for teacher education, with specific focus on the inclusion of environment and sustainability, also known as education for sustainable development (ESD) in the South African teacher education system. It reviews and reports on the history of environment and sustainability education in teacher education, and from this, the national case study begins to conceptualise a new approach to environment and sustainability teacher education within a new curriculum policy environment, and a new teacher education and development policy environment. Action research case study methodology is used to document the first phase of the emergence of this network, and this report covers Phase 1 of the initiative, which covers formation of the network, review of previous practices, three conceptual development pilot studies undertaken in both in-service and pre-service teacher education environments and a piloting of a ‘Train the Trainers’ or ‘Educate the Teacher Educators’ programme, which complements and extends the actual teacher education and development (TED) programme under development. The study highlights critical insights of relevance to the shift to a content referenced curriculum in South Africa, and shows how the ‘knowledge mix’ which forms the foundation of the new Teacher Education Qualifications Framework can be engaged. It also highlights some features of the changing knowledge environment, and what dominant knowledge practices are in environment and sustainability-related teaching and teacher education practices, opening these up for further scrutiny. It raises concerns that dominant knowledge work, while integrating a range of forms of knowledge (as is expected of the teacher education system under the new policy), tends to be limited by content on problems and issues for raising awareness, and fails to develop deeper conceptual depth and understanding of environment and sustainability, as issues based knowledge dominates. Similarly, it fails to support social innovation as a response to environment and sustainability concerns, as awareness raising dominates in dominant knowledge work. The study provides a revised conceptual framework for the Teacher Development Network (TEDN) programme, with guidance on key elements necessary to take the programme forward in Phase 2.
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Near Real-time Aggregation and Visualisation of Hostile Network Traffic
- Hunter, Samuel O, Irwin, Barry V W
- Authors: Hunter, Samuel O , Irwin, Barry V W
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428067 , vital:72484 , https://www.researchgate.net/profile/Barry-Irwin/publication/327622653_Near_Real-time_Aggregation_and_Visualisation_of_Hostile_Network_Traffic/links/5b9a1474a6fdcc59bf8dfcc2/Near-Real-time-Aggregation-and-Visualisation-of-Hostile-Network-Traffic.pdf4
- Description: Efficient utilization of hostile network traffic for visualization and defen-sive purposes require near real-time availability of such data. Hostile or malicious traffic was obtained through the use of network telescopes and honeypots, as they are effective at capturing mostly illegitimate and nefarious traffic. The data is then exposed in near real-time through a messaging framework and visualized with the help of a geolocation based visualization tool. Defensive applications with regards to hostile network traffic are explored; these include the dynamic quarantine of malicious hosts internal to a network and the egress filtering of denial of service traffic originating from inside a network.
- Full Text:
- Authors: Hunter, Samuel O , Irwin, Barry V W
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428067 , vital:72484 , https://www.researchgate.net/profile/Barry-Irwin/publication/327622653_Near_Real-time_Aggregation_and_Visualisation_of_Hostile_Network_Traffic/links/5b9a1474a6fdcc59bf8dfcc2/Near-Real-time-Aggregation-and-Visualisation-of-Hostile-Network-Traffic.pdf4
- Description: Efficient utilization of hostile network traffic for visualization and defen-sive purposes require near real-time availability of such data. Hostile or malicious traffic was obtained through the use of network telescopes and honeypots, as they are effective at capturing mostly illegitimate and nefarious traffic. The data is then exposed in near real-time through a messaging framework and visualized with the help of a geolocation based visualization tool. Defensive applications with regards to hostile network traffic are explored; these include the dynamic quarantine of malicious hosts internal to a network and the egress filtering of denial of service traffic originating from inside a network.
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Network neutral control over quality of service networks
- Foulkes, Phillip, Foss, Richard, Gurdan, Robby
- Authors: Foulkes, Phillip , Foss, Richard , Gurdan, Robby
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427166 , vital:72419 , https://www.aes.org/e-lib/online/browse.cfm?elib=16151
- Description: Creating interoperability between two standards-based network technologies, IEEE 1394 Firewire and Ethernet Audio/Video Bridging (AVB), allows them to exist simultaneously in a single application configuration. While both technologies provide the transport of synchronized, low-latency, real-time audio and video data, they have different approaches to enabling this transport. By using a compatible audio gateway with a common control protocol, audio devices on these disparate networks can be connected and controlled.
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- Authors: Foulkes, Phillip , Foss, Richard , Gurdan, Robby
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427166 , vital:72419 , https://www.aes.org/e-lib/online/browse.cfm?elib=16151
- Description: Creating interoperability between two standards-based network technologies, IEEE 1394 Firewire and Ethernet Audio/Video Bridging (AVB), allows them to exist simultaneously in a single application configuration. While both technologies provide the transport of synchronized, low-latency, real-time audio and video data, they have different approaches to enabling this transport. By using a compatible audio gateway with a common control protocol, audio devices on these disparate networks can be connected and controlled.
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Ontogenetic dietary shift and morphological correlates for Diplodus capensis (Teleostei Sparidae) in southern Angola
- Richardson, Timothy J, Potts, Warren M, Santos, Carmen V D, Sauer, Warwick H H
- Authors: Richardson, Timothy J , Potts, Warren M , Santos, Carmen V D , Sauer, Warwick H H
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443984 , vital:74176 , https://doi.org/10.1080/15627020.2011.11407501
- Description: Allometric growth patterns of functional morphological variables that reflect resource use in fish were correlated with the diet of Diplodus capensis in southern Angola. A total of 114 individuals (76–336 mm FL) were collected for stomach content analysis and a further 35 individuals (80–320 mm FL) for morphometric analysis. The major dietary components belonged to the groups Chlorophyta, Cirripedia, Rhodophyta and Bivalvia, and made up 71.7% of the diet in terms of a computed ranking index. There was a clear ontogenetic dietary shift with small fish feeding predominantly on algae and large fish on barnacles and mussels. This increasingly durophagous diet corresponded with a positive allometric growth pattern in the gape dimensions (width, height and surface area), adductor mandibulae muscle process and incisor width. Conversely, the relative gut length followed an isometric growth pattern, suggesting a decreased absorptive capacity. This isometric growth pattern is attributed to the better digestibility of the durophagous prey items when compared with algae and further corroborates a link between the morphology and an ontogenetic dietary shift observed in this species.
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- Authors: Richardson, Timothy J , Potts, Warren M , Santos, Carmen V D , Sauer, Warwick H H
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443984 , vital:74176 , https://doi.org/10.1080/15627020.2011.11407501
- Description: Allometric growth patterns of functional morphological variables that reflect resource use in fish were correlated with the diet of Diplodus capensis in southern Angola. A total of 114 individuals (76–336 mm FL) were collected for stomach content analysis and a further 35 individuals (80–320 mm FL) for morphometric analysis. The major dietary components belonged to the groups Chlorophyta, Cirripedia, Rhodophyta and Bivalvia, and made up 71.7% of the diet in terms of a computed ranking index. There was a clear ontogenetic dietary shift with small fish feeding predominantly on algae and large fish on barnacles and mussels. This increasingly durophagous diet corresponded with a positive allometric growth pattern in the gape dimensions (width, height and surface area), adductor mandibulae muscle process and incisor width. Conversely, the relative gut length followed an isometric growth pattern, suggesting a decreased absorptive capacity. This isometric growth pattern is attributed to the better digestibility of the durophagous prey items when compared with algae and further corroborates a link between the morphology and an ontogenetic dietary shift observed in this species.
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Optical limiting behavior of ring substituted zinc, indium and gallium phthalocyanines in the presence of quantum dots
- Britton, Jonathan, Litwinski, Christian, Durmus, Mahmut, Chauke, Vongani, Nyokong, Tebello
- Authors: Britton, Jonathan , Litwinski, Christian , Durmus, Mahmut , Chauke, Vongani , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247122 , vital:51548 , xlink:href="https://doi.org/10.1142/S1088424611004142"
- Description: This paper presents the study of the effects of CdTe-TGA quantum dots (QDs) on optical limiting ability of different phthalocyanine (Pc) complexes (1–10) containing Zn, Ga, In central metals and substituted with benzyloxyphenoxy, phenoxy, tert-butylphenoxy and amino groups. The optical limiting parameters of Pcs were higher for tert-butylphenoxy when compared to benzyloxyphenoxy and phenoxy substituents, in DMSO. Non-peripheral substitution decreased the optical limiting parameters. Third-order susceptibility (Im[χ(3)]/α) values of Pcs in the absence and presence of CdTe QDs were in the 10-12 to 10-10 esu.cm range. Hyperpolarizabilities (γ) ranged from 10-31 to 10-29 esu L for Pc alone or in mixture with QDs. There is a general improvement in optical limiting ability of Pc complexes in the presence of CdTe TGA QDs. Due to these promising results, future work can be implemented for the creation of Pc:QD thin films, which would then be examined to ensure that their optical limiting ability is still acceptable.
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- Authors: Britton, Jonathan , Litwinski, Christian , Durmus, Mahmut , Chauke, Vongani , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247122 , vital:51548 , xlink:href="https://doi.org/10.1142/S1088424611004142"
- Description: This paper presents the study of the effects of CdTe-TGA quantum dots (QDs) on optical limiting ability of different phthalocyanine (Pc) complexes (1–10) containing Zn, Ga, In central metals and substituted with benzyloxyphenoxy, phenoxy, tert-butylphenoxy and amino groups. The optical limiting parameters of Pcs were higher for tert-butylphenoxy when compared to benzyloxyphenoxy and phenoxy substituents, in DMSO. Non-peripheral substitution decreased the optical limiting parameters. Third-order susceptibility (Im[χ(3)]/α) values of Pcs in the absence and presence of CdTe QDs were in the 10-12 to 10-10 esu.cm range. Hyperpolarizabilities (γ) ranged from 10-31 to 10-29 esu L for Pc alone or in mixture with QDs. There is a general improvement in optical limiting ability of Pc complexes in the presence of CdTe TGA QDs. Due to these promising results, future work can be implemented for the creation of Pc:QD thin films, which would then be examined to ensure that their optical limiting ability is still acceptable.
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Optimal template removal from molecularly imprinted polymers by pressurized hot water extraction
- Batlokwa, Bareki Shima, Mokgadi, Janes, Nyokong, Tebello, Torto, Nelson
- Authors: Batlokwa, Bareki Shima , Mokgadi, Janes , Nyokong, Tebello , Torto, Nelson
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247813 , vital:51620 , xlink:href="https://doi.org/10.1007/s10337-010-1884-3"
- Description: An optimal extraction method for the removal of templates from molecularly imprinted polymers (MIPs) is presented. The extraction method is based on pressurized hot water extraction (PHWE). PHWE was evaluated by application to three distinctly colored MIPs for chlorophyll (green), quercetin (yellow) and phthalocynine (dark blue) with subsequent monitoring of template removal and template bleeding by an ultraviolet spectrophotometer. The templates were washed-off and the extraction efficiency (EE) was compared to that of soxhlet and ultrasonic extraction methods. PHWE employed hot water at an optimal temperature of 220 °C, pressure of 50 bars and flow rate of 2 mL min−1 to thoroughly wash-off the respective templates from their MIPs. The EE evaluated for PHWE was over 99.6% for all the MIPs with no subsequent or minimal template bleeding (more than 0.01%). The washing procedure was simple and relatively fast as it was achieved in 70 min at the most. At 95% confidence level (n = 3), soxhlet and ultrasonic recorded EE that was not significantly different (more than 94.5% in all cases) from that of PHWE (less than 99.6% in all cases). Soxhlet and ultrasonic had washing procedures that were slower (over 18 h) and employed large quantities (400 mL) of organic solvents modified with acids. The percentage relative standard deviations (%RSD) for the EE and recovery results were less than 2.3% in all cases indicating the high reproducibility of the method. Overall, the three methods performed comparably in extracting templates. PHWE seems to be the method of choice as it employed water which poses no environmental threat.
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- Authors: Batlokwa, Bareki Shima , Mokgadi, Janes , Nyokong, Tebello , Torto, Nelson
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247813 , vital:51620 , xlink:href="https://doi.org/10.1007/s10337-010-1884-3"
- Description: An optimal extraction method for the removal of templates from molecularly imprinted polymers (MIPs) is presented. The extraction method is based on pressurized hot water extraction (PHWE). PHWE was evaluated by application to three distinctly colored MIPs for chlorophyll (green), quercetin (yellow) and phthalocynine (dark blue) with subsequent monitoring of template removal and template bleeding by an ultraviolet spectrophotometer. The templates were washed-off and the extraction efficiency (EE) was compared to that of soxhlet and ultrasonic extraction methods. PHWE employed hot water at an optimal temperature of 220 °C, pressure of 50 bars and flow rate of 2 mL min−1 to thoroughly wash-off the respective templates from their MIPs. The EE evaluated for PHWE was over 99.6% for all the MIPs with no subsequent or minimal template bleeding (more than 0.01%). The washing procedure was simple and relatively fast as it was achieved in 70 min at the most. At 95% confidence level (n = 3), soxhlet and ultrasonic recorded EE that was not significantly different (more than 94.5% in all cases) from that of PHWE (less than 99.6% in all cases). Soxhlet and ultrasonic had washing procedures that were slower (over 18 h) and employed large quantities (400 mL) of organic solvents modified with acids. The percentage relative standard deviations (%RSD) for the EE and recovery results were less than 2.3% in all cases indicating the high reproducibility of the method. Overall, the three methods performed comparably in extracting templates. PHWE seems to be the method of choice as it employed water which poses no environmental threat.
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Optimizing the electrocatalytic activity of surface confined Co macrocyclics for the electrooxidation of thiocyanate at pH 4
- Tshangana, Charmaine, Pavez, Jorge, Gulppi, Miguel A, De Mattos, Ivanildo Luiz, Arratia-Perez, Ramiro, Linares-Flores, Cristian, Paez, Maritza, Nyokong, Tebello, Zagal, Jos H
- Authors: Tshangana, Charmaine , Pavez, Jorge , Gulppi, Miguel A , De Mattos, Ivanildo Luiz , Arratia-Perez, Ramiro , Linares-Flores, Cristian , Paez, Maritza , Nyokong, Tebello , Zagal, Jos H
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247726 , vital:51612 , xlink:href="https://doi.org/10.1002/elan.201000599"
- Description: We have studied the trends in catalytic activity of several Co macrocyclics confined on the surface graphite electrodes for the oxidation of thiocyanate. A plot of log i (at constant E) versus the formal potential of the catalyst gives a volcano correlation, indicating that the Co(II/I) redox potential needs to be tuned, in order to achieve maximum reactivity. Graphite electrodes modified with Co phthalocyanine at pH 4 exhibit linear amperometric response for thiocyanate concentration in the range 10−7 and 10−3 M. Theoretical calculations show that electrocatalytic activity (as log i at constant E) plotted versus the energy of the LUMO of the Co complex also gives a volcano correlation.
- Full Text:
- Authors: Tshangana, Charmaine , Pavez, Jorge , Gulppi, Miguel A , De Mattos, Ivanildo Luiz , Arratia-Perez, Ramiro , Linares-Flores, Cristian , Paez, Maritza , Nyokong, Tebello , Zagal, Jos H
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247726 , vital:51612 , xlink:href="https://doi.org/10.1002/elan.201000599"
- Description: We have studied the trends in catalytic activity of several Co macrocyclics confined on the surface graphite electrodes for the oxidation of thiocyanate. A plot of log i (at constant E) versus the formal potential of the catalyst gives a volcano correlation, indicating that the Co(II/I) redox potential needs to be tuned, in order to achieve maximum reactivity. Graphite electrodes modified with Co phthalocyanine at pH 4 exhibit linear amperometric response for thiocyanate concentration in the range 10−7 and 10−3 M. Theoretical calculations show that electrocatalytic activity (as log i at constant E) plotted versus the energy of the LUMO of the Co complex also gives a volcano correlation.
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Paper bridges: a critical examination of the Daily Dispatch's ‘community dialogues’
- Authors: Amner, Roderick J
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142645 , vital:38098 , https://doi.org/10.1080/02560054.2011.545564
- Description: A series of town-hall-like meetings called the ‘community dialogues’ were conducted in 2009 by the Daily Dispatch newspaper in East London, under the banner of public/civic journalism, a global journalistic reform movement begun in the United States in the late 1980s. the editorial leadership of the newspaper imagined a number of core journalistic and civic purposes for the dialogues and succeeded in achieving some of these. However, the newspaper's claim that the dialogues could help to build ‘horizontal bridges’ between diverse communities in East London is critically examined through the example of two community dialogues which took place in neighbouring locations - the predominantly white, middle-class suburb of Beacon Bay, and the informal African settlement of Nompumelelo - on consecutive days in 2009. This article argues that social inequalities, particularly acute in the South African context, may preclude the emergence of a shared vision of the common good, and that joint deliberation between diverse social groups in the pursuit of consensus may not be realistic or even an appropriate goal, especially if it means ratifying an unjust status quo.
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- Authors: Amner, Roderick J
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142645 , vital:38098 , https://doi.org/10.1080/02560054.2011.545564
- Description: A series of town-hall-like meetings called the ‘community dialogues’ were conducted in 2009 by the Daily Dispatch newspaper in East London, under the banner of public/civic journalism, a global journalistic reform movement begun in the United States in the late 1980s. the editorial leadership of the newspaper imagined a number of core journalistic and civic purposes for the dialogues and succeeded in achieving some of these. However, the newspaper's claim that the dialogues could help to build ‘horizontal bridges’ between diverse communities in East London is critically examined through the example of two community dialogues which took place in neighbouring locations - the predominantly white, middle-class suburb of Beacon Bay, and the informal African settlement of Nompumelelo - on consecutive days in 2009. This article argues that social inequalities, particularly acute in the South African context, may preclude the emergence of a shared vision of the common good, and that joint deliberation between diverse social groups in the pursuit of consensus may not be realistic or even an appropriate goal, especially if it means ratifying an unjust status quo.
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Photocatalytic behaviour of tantalum (V) phthalocyanines in the presence of gold nanoparticles towards the oxidation of cyclohexene
- Chauke, Vongani P, Antunes, Edith M, Chidawanyika, Wadzanai J U, Nyokong, Tebello
- Authors: Chauke, Vongani P , Antunes, Edith M , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247904 , vital:51628 , xlink:href="https://doi.org/10.1016/j.molcata.2010.11.023"
- Description: This paper presents the photocatalytic oxidation of cyclohexene using (OH)3TaPc derivatives in the absence or presence of gold nanoparticles (AuNPs). The photochemical parameters that include photodegradation (ΦP) and singlet oxygen (ΦΔ) quantum yields are also reported in this work. The ΦΔ values were 0.47 and 0.36 for complexes 1a and 1b, respectively. The ΦΔ values improved drastically in the presence of AuNPs to 0.75 and 0.88, respectively. The ΦP values ranged from 1.02 to 2.45 × 10−6, showing stability of TaPc derivatives in the absence and presence of AuNPs. The photocatalytic products identified using gas chromatograph (GC) are cyclohexene oxide, 2-cyclohexen-1-ol, 2-cyclohexene-1-one and 1,2-cyclohexanediol. The percentage conversion values were higher in the presence of AuNPs. Singlet oxygen was determined to be the main agent involved in the photocatalytic oxidation of cyclohexene. The product yield percentage values for both TaPc complexes (1a and 1b) and TaPc in the presence of AuNPs ranged from 6.3 to 21.2%.
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- Authors: Chauke, Vongani P , Antunes, Edith M , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247904 , vital:51628 , xlink:href="https://doi.org/10.1016/j.molcata.2010.11.023"
- Description: This paper presents the photocatalytic oxidation of cyclohexene using (OH)3TaPc derivatives in the absence or presence of gold nanoparticles (AuNPs). The photochemical parameters that include photodegradation (ΦP) and singlet oxygen (ΦΔ) quantum yields are also reported in this work. The ΦΔ values were 0.47 and 0.36 for complexes 1a and 1b, respectively. The ΦΔ values improved drastically in the presence of AuNPs to 0.75 and 0.88, respectively. The ΦP values ranged from 1.02 to 2.45 × 10−6, showing stability of TaPc derivatives in the absence and presence of AuNPs. The photocatalytic products identified using gas chromatograph (GC) are cyclohexene oxide, 2-cyclohexen-1-ol, 2-cyclohexene-1-one and 1,2-cyclohexanediol. The percentage conversion values were higher in the presence of AuNPs. Singlet oxygen was determined to be the main agent involved in the photocatalytic oxidation of cyclohexene. The product yield percentage values for both TaPc complexes (1a and 1b) and TaPc in the presence of AuNPs ranged from 6.3 to 21.2%.
- Full Text: