Life history strategy and population characteristics of an unexploited riverine cyprinid, Labeo capensis, in the largest impoundment in the Orange River Basin
- 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: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124910 , vital:35709 , https://doi.10.3377/004.047.0124
- 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:
- Date Issued: 2012
- Authors: Winker, A Henning , Weyl, Olaf L F , Booth, Anthony J , Ellender, Bruce R
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124910 , vital:35709 , https://doi.10.3377/004.047.0124
- 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:
- Date Issued: 2012
Life-history characteristics of an age-validated established invasive African sharptooth catfish, Clarias gariepinus, population in a warm–temperate African impoundment
- Wartenberg, Reece, Weyl, Olaf L F, Booth, Anthony J, Winker, A Henning
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124921 , vital:35710 , https://doi.10.3377/004.048.0225
- Description: African sharptooth catfish Clarias gariepinus (Burchell, 1822) is a widely distributed fish that has now invaded water bodies in South America, Eastern Europe, Asia and South Africa (Cambray 2003). In South Africa it is native as far south as the Orange-Vaal river system, but inter-basin water transfer schemes (IBWTs), illegal stocking by anglers and from aquaculture has resulted in the establishment of extralimital populations in almost all river systems (van Rensburg et al. 2011). Within the Eastern Cape Province, C. gariepinus has invaded the Great Fish and Sundays rivers through IBWTs, that connect the Orange River to the Great Fish River and then to the Sundays River system which flows directly into Darlington Dam (Kadye & Booth 2013a) (Fig. 1). Soon after the completion of the IBWTs sharptooth catfish were recorded in Grassridge Dam in 1976 (Laurenson & Hocutt 1985), and later from Darlington Dam in 1981 (Scott et al. 2006). Although Cambray & Jubb (1977) are of the opinion that the species was translocated prior to the IBWT connection, there is now a permanent corridor between the Orange River and its receiving river systems that can facilitate the continued introduction of non-native Orange River fishes and other aquatic biota.
- Full Text:
- Date Issued: 2012
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124921 , vital:35710 , https://doi.10.3377/004.048.0225
- Description: African sharptooth catfish Clarias gariepinus (Burchell, 1822) is a widely distributed fish that has now invaded water bodies in South America, Eastern Europe, Asia and South Africa (Cambray 2003). In South Africa it is native as far south as the Orange-Vaal river system, but inter-basin water transfer schemes (IBWTs), illegal stocking by anglers and from aquaculture has resulted in the establishment of extralimital populations in almost all river systems (van Rensburg et al. 2011). Within the Eastern Cape Province, C. gariepinus has invaded the Great Fish and Sundays rivers through IBWTs, that connect the Orange River to the Great Fish River and then to the Sundays River system which flows directly into Darlington Dam (Kadye & Booth 2013a) (Fig. 1). Soon after the completion of the IBWTs sharptooth catfish were recorded in Grassridge Dam in 1976 (Laurenson & Hocutt 1985), and later from Darlington Dam in 1981 (Scott et al. 2006). Although Cambray & Jubb (1977) are of the opinion that the species was translocated prior to the IBWT connection, there is now a permanent corridor between the Orange River and its receiving river systems that can facilitate the continued introduction of non-native Orange River fishes and other aquatic biota.
- Full Text:
- Date Issued: 2012
Linking poverty, HIV/AIDS and climate change to human and ecosystem vulnerability in southern Africa: Consequences for livelihoods and sustainable ecosystem management
- Shackleton, Sheona E, Shackleton, Charlie M
- Authors: Shackleton, Sheona E , Shackleton, Charlie M
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181081 , vital:43697 , xlink:href="https://doi.org/10.1080/13504509.2011.641039"
- Description: People in southern Africa are facing escalating levels of risk, uncertainty and consequently vulnerability as a result of multiple interacting stressors, including HIV/AIDS, poverty, food insecurity, weak governance, climate change and land degradation, to name but a few. Vulnerability or livelihood insecurity emerges when poor people as individuals or social units have to face harmful threats or shocks with inadequate capacity to respond effectively. In such situations, people often have no choice but to turn to their immediate environment for support. Evidence suggests that rising levels of human vulnerability are driving increased dependency on biodiversity and ecosystem services, which in turn, and along with other threats, is rendering ecosystems more vulnerable. This paper explores the dynamic and complex linkages and feedbacks between human vulnerability and ecosystem vulnerability, drawing on data from the southern African region. Human vulnerability is conceptualized as a threat to ecosystem health, as driven by the interplay between a number of current and emerging factors. We focus on poverty, HIV/AIDS and more intense climate extremes as examples of stressors on livelihoods and direct and indirect drivers of ecosystem change. We discuss how some of the responses to increased vulnerability may pose threats to biodiversity conservation, ecosystem management and sustainable development, whilst considering potential solutions that rely on a thorough understanding of coupled social–ecological systems and the interplay between multiple stressors and responses at different scales.
- Full Text:
- Date Issued: 2012
- Authors: Shackleton, Sheona E , Shackleton, Charlie M
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181081 , vital:43697 , xlink:href="https://doi.org/10.1080/13504509.2011.641039"
- Description: People in southern Africa are facing escalating levels of risk, uncertainty and consequently vulnerability as a result of multiple interacting stressors, including HIV/AIDS, poverty, food insecurity, weak governance, climate change and land degradation, to name but a few. Vulnerability or livelihood insecurity emerges when poor people as individuals or social units have to face harmful threats or shocks with inadequate capacity to respond effectively. In such situations, people often have no choice but to turn to their immediate environment for support. Evidence suggests that rising levels of human vulnerability are driving increased dependency on biodiversity and ecosystem services, which in turn, and along with other threats, is rendering ecosystems more vulnerable. This paper explores the dynamic and complex linkages and feedbacks between human vulnerability and ecosystem vulnerability, drawing on data from the southern African region. Human vulnerability is conceptualized as a threat to ecosystem health, as driven by the interplay between a number of current and emerging factors. We focus on poverty, HIV/AIDS and more intense climate extremes as examples of stressors on livelihoods and direct and indirect drivers of ecosystem change. We discuss how some of the responses to increased vulnerability may pose threats to biodiversity conservation, ecosystem management and sustainable development, whilst considering potential solutions that rely on a thorough understanding of coupled social–ecological systems and the interplay between multiple stressors and responses at different scales.
- Full Text:
- Date Issued: 2012
Living lab methodology as an approach to innovation in ICT4D: The Siyakhula Living Lab experience
- Gumbo, Sibukelo, Thinyane, Hannah, Thinyane, Mamello, Terzoli, Alfredo, Hansen, Susan
- Authors: Gumbo, Sibukelo , Thinyane, Hannah , Thinyane, Mamello , Terzoli, Alfredo , Hansen, Susan
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431302 , vital:72762 , https://www.siyakhulall.com/sites/default/files/ISTAfrica_Paper_ref_18_doc_4809_0.pdf
- Description: Underdevelopment and poverty represent key challenges faced by the modern world, which have attracted the attention of NGOs, civil society, government and multinationals. Various undertakings including the United Nations Millennium Development Goals articulation and the World Summit on Information Society highlight the global commitment towards addressing these problems. The solutions to these problems should be derived out of well-structured innovation systems that take into consideration the grassroot context and concerns. A number of in-novation models have been formulated and utilized effectively in differ-ent industries, and some of these have equally been used effectively in community development contexts. This paper elaborates on the Living Lab methodology and its application in ICT4D contexts, highlighting the effectiveness of this model towards integrating end-users within their problem solving effort. This is discussed through the backdrop of the Siyakhula Living Lab, an ICT4D intervention. The embedding environ-ment for this model, which enables key synergies with other stakehold-ers, is also discussed.
- Full Text:
- Date Issued: 2012
- Authors: Gumbo, Sibukelo , Thinyane, Hannah , Thinyane, Mamello , Terzoli, Alfredo , Hansen, Susan
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431302 , vital:72762 , https://www.siyakhulall.com/sites/default/files/ISTAfrica_Paper_ref_18_doc_4809_0.pdf
- Description: Underdevelopment and poverty represent key challenges faced by the modern world, which have attracted the attention of NGOs, civil society, government and multinationals. Various undertakings including the United Nations Millennium Development Goals articulation and the World Summit on Information Society highlight the global commitment towards addressing these problems. The solutions to these problems should be derived out of well-structured innovation systems that take into consideration the grassroot context and concerns. A number of in-novation models have been formulated and utilized effectively in differ-ent industries, and some of these have equally been used effectively in community development contexts. This paper elaborates on the Living Lab methodology and its application in ICT4D contexts, highlighting the effectiveness of this model towards integrating end-users within their problem solving effort. This is discussed through the backdrop of the Siyakhula Living Lab, an ICT4D intervention. The embedding environ-ment for this model, which enables key synergies with other stakehold-ers, is also discussed.
- Full Text:
- Date Issued: 2012
Long-term catch and effort trends in Eastern Cape Angling Week competitions
- Dicken, Matthew L, Smale, Malcolm J, Booth, Anthony J
- Authors: Dicken, Matthew L , Smale, Malcolm J , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124931 , vital:35711 , https://doi.org/10.2989/1814232X.2012.709961
- Description: Recreational shore-based angling is one of the most popular sport and outdoor activity pastimes in South Africa with an estimated 412 000 fishers (McGrath et al. 1997). It is a form of linefishing where fish are caught using a hook and line and comprises a social as well as a more formal organized competitive sector (van der Elst 1989). Similar to other components of the linefishery, which include the subsistence as well as boat-based commercial sectors, excessive shore-fishing effort along the Eastern Cape has resulted not only in declining catches (Bennett 1991, Griffiths 1997, Brouwer and Buxton 2002, Pradervand and Govender 2003) but also changes in the species composition of catches (Bennett et al. 1994, Brouwer et al. 1997, Attwood and Farquhar 1999). Stock assessments indicate that many important linefish species are severely overexploited (Griffiths 1997, Hutchings 2000, Mann 2000) and that continued fishing pressure threatens endemic linefish populations. In 1996, shore-anglers alone were responsible for an annual catch of approximately 4.5 million fish, weighing around 3 000 tonnes (Brouwer et al. 1997).
- Full Text:
- Date Issued: 2012
- Authors: Dicken, Matthew L , Smale, Malcolm J , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124931 , vital:35711 , https://doi.org/10.2989/1814232X.2012.709961
- Description: Recreational shore-based angling is one of the most popular sport and outdoor activity pastimes in South Africa with an estimated 412 000 fishers (McGrath et al. 1997). It is a form of linefishing where fish are caught using a hook and line and comprises a social as well as a more formal organized competitive sector (van der Elst 1989). Similar to other components of the linefishery, which include the subsistence as well as boat-based commercial sectors, excessive shore-fishing effort along the Eastern Cape has resulted not only in declining catches (Bennett 1991, Griffiths 1997, Brouwer and Buxton 2002, Pradervand and Govender 2003) but also changes in the species composition of catches (Bennett et al. 1994, Brouwer et al. 1997, Attwood and Farquhar 1999). Stock assessments indicate that many important linefish species are severely overexploited (Griffiths 1997, Hutchings 2000, Mann 2000) and that continued fishing pressure threatens endemic linefish populations. In 1996, shore-anglers alone were responsible for an annual catch of approximately 4.5 million fish, weighing around 3 000 tonnes (Brouwer et al. 1997).
- Full Text:
- Date Issued: 2012
Lost in translation: Transformation in the first round of institutional audits
- Authors: McKenna, Sioux , Quinn, Lynn
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187384 , vital:44627 , xlink:href="https://hdl.handle.net/10520/EJC132752"
- Description: The South African higher education institutional audit process was introduced alongside similar endeavors internationally. However, despite many similarities, each country foregrounds different concerns within their higher education quality processes. In their seminal article, Harvey and Green suggest five possible notions of quality, one of which is quality as transformation, and in South Africa the message has been clearly stated: notions of quality are intricately related to transformation. Local research has however suggested that the notion of 'transformation' as quality takes on particular nuances within the country’s context. In the two institutional case studies presented here, the 'quality as transformation' discourse appears to have been largely lost in translation. In one university transformation was not called upon to construct notions of quality; quality was primarily constructed by a discourse of excellence. In the other institution, the transformation aspects of quality seem to have been interpreted in a particularly reductionist way as relating solely to racial demographics. In both cases, this article argues that the 'quality as transformation' discourse prevalent in the audit documentation in the South African context was lost somewhere between the intentions embodied in national documents and the processes embarked upon by institutions.
- Full Text:
- Date Issued: 2012
- Authors: McKenna, Sioux , Quinn, Lynn
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187384 , vital:44627 , xlink:href="https://hdl.handle.net/10520/EJC132752"
- Description: The South African higher education institutional audit process was introduced alongside similar endeavors internationally. However, despite many similarities, each country foregrounds different concerns within their higher education quality processes. In their seminal article, Harvey and Green suggest five possible notions of quality, one of which is quality as transformation, and in South Africa the message has been clearly stated: notions of quality are intricately related to transformation. Local research has however suggested that the notion of 'transformation' as quality takes on particular nuances within the country’s context. In the two institutional case studies presented here, the 'quality as transformation' discourse appears to have been largely lost in translation. In one university transformation was not called upon to construct notions of quality; quality was primarily constructed by a discourse of excellence. In the other institution, the transformation aspects of quality seem to have been interpreted in a particularly reductionist way as relating solely to racial demographics. In both cases, this article argues that the 'quality as transformation' discourse prevalent in the audit documentation in the South African context was lost somewhere between the intentions embodied in national documents and the processes embarked upon by institutions.
- Full Text:
- Date Issued: 2012
Mapping the most significant computer hacking events to a temporal computer attack model
- Van Heerden, Renier, Pieterse, Heloise, Irwin, Barry V W
- Authors: Van Heerden, Renier , Pieterse, Heloise , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429950 , vital:72654 , https://doi.org/10.1007/978-3-642-33332-3_21
- Description: This paper presents eight of the most significant computer hacking events (also known as computer attacks). These events were selected because of their unique impact, methodology, or other properties. A temporal computer attack model is presented that can be used to model computer based attacks. This model consists of the following stages: Target Identification, Reconnaissance, Attack, and Post-Attack Recon-naissance stages. The Attack stage is separated into: Ramp-up, Dam-age and Residue. This paper demonstrates how our eight significant hacking events are mapped to the temporal computer attack model. The temporal computer attack model becomes a valuable asset in the protection of critical infrastructure by being able to detect similar attacks earlier.
- Full Text:
- Date Issued: 2012
- Authors: Van Heerden, Renier , Pieterse, Heloise , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429950 , vital:72654 , https://doi.org/10.1007/978-3-642-33332-3_21
- Description: This paper presents eight of the most significant computer hacking events (also known as computer attacks). These events were selected because of their unique impact, methodology, or other properties. A temporal computer attack model is presented that can be used to model computer based attacks. This model consists of the following stages: Target Identification, Reconnaissance, Attack, and Post-Attack Recon-naissance stages. The Attack stage is separated into: Ramp-up, Dam-age and Residue. This paper demonstrates how our eight significant hacking events are mapped to the temporal computer attack model. The temporal computer attack model becomes a valuable asset in the protection of critical infrastructure by being able to detect similar attacks earlier.
- Full Text:
- Date Issued: 2012
Marx, Weber and NGOs:
- Authors: Helliker, Kirk D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144738 , vital:38375 , DOI: 10.1080/21528586.2007.10419171
- Description: This article offers a sociological understanding of intermediary NGOs in the modern world. In does so by drawing on certain epistemological insights of Marx and Weber, and this entails methodologies of both deconstruction and reconstruction. In arguing against a sociological behaviourism that pervades the NGO literature, the article conceptualises intermediary NGOs as a ‘social form’ embodying contradictory relations. For analytical purposes, the contradiction between ‘the global’ and ‘the local’ is brought to the fore.
- Full Text:
- Date Issued: 2012
- Authors: Helliker, Kirk D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144738 , vital:38375 , DOI: 10.1080/21528586.2007.10419171
- Description: This article offers a sociological understanding of intermediary NGOs in the modern world. In does so by drawing on certain epistemological insights of Marx and Weber, and this entails methodologies of both deconstruction and reconstruction. In arguing against a sociological behaviourism that pervades the NGO literature, the article conceptualises intermediary NGOs as a ‘social form’ embodying contradictory relations. For analytical purposes, the contradiction between ‘the global’ and ‘the local’ is brought to the fore.
- Full Text:
- Date Issued: 2012
Microbial monitoring of surface water in South Africa: an overview
- Luyt, Catherine D, Tandlich, Roman, Muller, Wilhelmine J, Wilhelmi, Brendan S
- Authors: Luyt, Catherine D , Tandlich, Roman , Muller, Wilhelmine J , Wilhelmi, Brendan S
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71636 , vital:29927 , https://doi.org/10.3390/ijerph9082669
- Description: Infrastructural problems force South African households to supplement their drinking water consumption from water resources of inadequate microbial quality. Microbial water quality monitoring is currently based on the Colilert®18 system which leads to rapidly available results. Using Escherichia coli as the indicator microorganism limits the influence of environmental sources on the reported results. The current system allows for understanding of long-term trends of microbial surface water quality and the related public health risks. However, rates of false positive for the Colilert®18-derived concentrations have been reported to range from 7.4% to 36.4%. At the same time, rates of false negative results vary from 3.5% to 12.5%; and the Colilert medium has been reported to provide for cultivation of only 56.8% of relevant strains. Identification of unknown sources of faecal contamination is not currently feasible. Based on literature review, calibration of the antibiotic-resistance spectra of Escherichia coli or the bifidobacterial tracking ratio should be investigated locally for potential implementation into the existing monitoring system. The current system could be too costly to implement in certain areas of South Africa where the modified H2S strip test might be used as a surrogate for the Colilert®18.
- Full Text:
- Date Issued: 2012
- Authors: Luyt, Catherine D , Tandlich, Roman , Muller, Wilhelmine J , Wilhelmi, Brendan S
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71636 , vital:29927 , https://doi.org/10.3390/ijerph9082669
- Description: Infrastructural problems force South African households to supplement their drinking water consumption from water resources of inadequate microbial quality. Microbial water quality monitoring is currently based on the Colilert®18 system which leads to rapidly available results. Using Escherichia coli as the indicator microorganism limits the influence of environmental sources on the reported results. The current system allows for understanding of long-term trends of microbial surface water quality and the related public health risks. However, rates of false positive for the Colilert®18-derived concentrations have been reported to range from 7.4% to 36.4%. At the same time, rates of false negative results vary from 3.5% to 12.5%; and the Colilert medium has been reported to provide for cultivation of only 56.8% of relevant strains. Identification of unknown sources of faecal contamination is not currently feasible. Based on literature review, calibration of the antibiotic-resistance spectra of Escherichia coli or the bifidobacterial tracking ratio should be investigated locally for potential implementation into the existing monitoring system. The current system could be too costly to implement in certain areas of South Africa where the modified H2S strip test might be used as a surrogate for the Colilert®18.
- Full Text:
- Date Issued: 2012
Mobile: the challenge of a unique new space for journalism: have you got your mojo?
- Authors: Malila, Vanessa
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159517 , vital:40304 , https://hdl.handle.net/10520/EJC135832
- Description: The speed with which technology is improving in the mobile communications market is widening the scope for opportunity to engage with audiences, provide information and capture their attention for that little while longer. Current technology such as 3G wireless technologies, which allow for high-speed data transmission, and access to multimedia content, as well as smart phones and tablet computers have already illustrated the potential for users to access information that is tailored to mobile devices and available anywhere.
- Full Text:
- Date Issued: 2012
- Authors: Malila, Vanessa
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159517 , vital:40304 , https://hdl.handle.net/10520/EJC135832
- Description: The speed with which technology is improving in the mobile communications market is widening the scope for opportunity to engage with audiences, provide information and capture their attention for that little while longer. Current technology such as 3G wireless technologies, which allow for high-speed data transmission, and access to multimedia content, as well as smart phones and tablet computers have already illustrated the potential for users to access information that is tailored to mobile devices and available anywhere.
- Full Text:
- Date Issued: 2012
Molecular catalysis of the oxygen reduction reaction by iron porphyrin catalysts tethered into Nafion layers
- He, Qinggang, Mugadza, Tawanda, Kang, Xiongwu, Zhu, Xiaobing, Chen, Shaowei, Kerr, John, Nyokong, Tebello
- Authors: He, Qinggang , Mugadza, Tawanda , Kang, Xiongwu , Zhu, Xiaobing , Chen, Shaowei , Kerr, John , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243168 , vital:51123 , xlink:href="https://doi.org/10.1016/j.jpowsour.2012.05.043"
- Description: This study was motivated by the need for improved understanding of the kinetics and transport phenomena in a homogeneous catalyst system for the oxygen reduction reaction (ORR). Direct interaction between the sulfonic groups of Nafion and an Fe(III) meso-tetra(N-methyl-4-pyridyl) porphine chloride (Fe(III)TMPyP) compound was observed using FTIR and in situ UV–Vis spectroelectrochemical characterizations. A positive shift of the half wave potential value (E1/2) for ORR on the iron porphyrin catalyst (Fe(III)TMPyP) was observed upon addition of a specific quantity of Nafion ionomer on a glassy carbon working electrode, indicating not only a faster charge transfer rate but also the role of protonation in the oxygen reduction reaction (ORR) process. A membrane electrode assembly (MEA) was made as a sandwich of a Pt-coated anode, a Nafion® 212 membrane, and a Fe(III)TMPyP + Nafion ionomer-coated cathode. This three-dimensional catalysis system has been demonstrated to be working in a H2/O2 proton exchange membrane (PEM) fuel cell test.
- Full Text:
- Date Issued: 2012
- Authors: He, Qinggang , Mugadza, Tawanda , Kang, Xiongwu , Zhu, Xiaobing , Chen, Shaowei , Kerr, John , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243168 , vital:51123 , xlink:href="https://doi.org/10.1016/j.jpowsour.2012.05.043"
- Description: This study was motivated by the need for improved understanding of the kinetics and transport phenomena in a homogeneous catalyst system for the oxygen reduction reaction (ORR). Direct interaction between the sulfonic groups of Nafion and an Fe(III) meso-tetra(N-methyl-4-pyridyl) porphine chloride (Fe(III)TMPyP) compound was observed using FTIR and in situ UV–Vis spectroelectrochemical characterizations. A positive shift of the half wave potential value (E1/2) for ORR on the iron porphyrin catalyst (Fe(III)TMPyP) was observed upon addition of a specific quantity of Nafion ionomer on a glassy carbon working electrode, indicating not only a faster charge transfer rate but also the role of protonation in the oxygen reduction reaction (ORR) process. A membrane electrode assembly (MEA) was made as a sandwich of a Pt-coated anode, a Nafion® 212 membrane, and a Fe(III)TMPyP + Nafion ionomer-coated cathode. This three-dimensional catalysis system has been demonstrated to be working in a H2/O2 proton exchange membrane (PEM) fuel cell test.
- Full Text:
- Date Issued: 2012
Molecular phylogenetics of Oestroidea (Diptera: Calyptratae) with emphasis on Calliphoridae: insights into the inter-familial relationships and additional evidence for paraphyly among blowflies
- Marinho, M A T, Junqueira, A C M, Paulo, D F, Esposito, M C T, Villet, Martin H, Azeredo-Espin, A D
- Authors: Marinho, M A T , Junqueira, A C M , Paulo, D F , Esposito, M C T , Villet, Martin H , Azeredo-Espin, A D
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442691 , vital:74023 , https://doi.org/10.1016/j.ympev.2012.08.007
- Description: The superfamily Oestroidea, comprising ∼15,000 species, is a large and ecologically diverse clade within the order Diptera. Among its six commonly recognized families, Calliphoridae seems to be crucial for understanding evolutionary relationships in the group, as it is recognized as a controversial paraphyletic grouping. To further investigate this matter, the ITS2, 28S, COI and 16S regions were used to infer phylogenetic relationships in Oestroidea with maximum-parsimony (MP), maximum-likelihood (ML) and Bayesian inference (BI) methods. For the BI analyses, a deep evaluation of different data partitioning strategies was conducted, including consideration of structural conformation (ITS2 and 16S) and codon position (COI) information.
- Full Text:
- Date Issued: 2012
- Authors: Marinho, M A T , Junqueira, A C M , Paulo, D F , Esposito, M C T , Villet, Martin H , Azeredo-Espin, A D
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442691 , vital:74023 , https://doi.org/10.1016/j.ympev.2012.08.007
- Description: The superfamily Oestroidea, comprising ∼15,000 species, is a large and ecologically diverse clade within the order Diptera. Among its six commonly recognized families, Calliphoridae seems to be crucial for understanding evolutionary relationships in the group, as it is recognized as a controversial paraphyletic grouping. To further investigate this matter, the ITS2, 28S, COI and 16S regions were used to infer phylogenetic relationships in Oestroidea with maximum-parsimony (MP), maximum-likelihood (ML) and Bayesian inference (BI) methods. For the BI analyses, a deep evaluation of different data partitioning strategies was conducted, including consideration of structural conformation (ITS2 and 16S) and codon position (COI) information.
- Full Text:
- Date Issued: 2012
Mortgage bonds and the right of access to adequate housing in South Africa: Gundwana v Stoke Development and Others 2011 (3) SA 608 (CC)
- Authors: Juma, Laurence
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127479 , vital:36015 , https://hdl.handle.net/10520/EJC129329
- Description: This article offers a critique of Gundwana v Stoke Development and Others 2011 (3) SA 608 (CC), a case in which the Constitutional Court of South Africa found it to be unconstitutional for the registrar of a high court to declare immovable properties specially executable when ordering a default judgement, to the extent that such an order "permitted the sale and execution of a home of a person". The Court interpreted the property clause in section 25, access to right to housing in section 26 of the Constitution, as mandating "further judicial oversight" in all cases where execution is levied against residential property. The article raises some of the shortcomings of this interpretive scheme and suggests that constitutional values, when used to curtail or enlarge obligations of parties to a mortgage bond, must take into account the general rights and duties which the parties assumed at the signing of the agreement; the circumstances of each of the parties at the time of execution and ascertained through a careful evaluation based on a clearly articulated set of principles, and the nature of constitutional rights themselves. The article argues that, whereas there may be circumstances in which a debtor may need protection, rather than impose a blanket abrogation of procedures allowing for expedient disposal of uncontested claims, the court should instead have considered the establishment of further procedural safeguards.
- Full Text: false
- Date Issued: 2012
- Authors: Juma, Laurence
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127479 , vital:36015 , https://hdl.handle.net/10520/EJC129329
- Description: This article offers a critique of Gundwana v Stoke Development and Others 2011 (3) SA 608 (CC), a case in which the Constitutional Court of South Africa found it to be unconstitutional for the registrar of a high court to declare immovable properties specially executable when ordering a default judgement, to the extent that such an order "permitted the sale and execution of a home of a person". The Court interpreted the property clause in section 25, access to right to housing in section 26 of the Constitution, as mandating "further judicial oversight" in all cases where execution is levied against residential property. The article raises some of the shortcomings of this interpretive scheme and suggests that constitutional values, when used to curtail or enlarge obligations of parties to a mortgage bond, must take into account the general rights and duties which the parties assumed at the signing of the agreement; the circumstances of each of the parties at the time of execution and ascertained through a careful evaluation based on a clearly articulated set of principles, and the nature of constitutional rights themselves. The article argues that, whereas there may be circumstances in which a debtor may need protection, rather than impose a blanket abrogation of procedures allowing for expedient disposal of uncontested claims, the court should instead have considered the establishment of further procedural safeguards.
- Full Text: false
- Date Issued: 2012
Network telescope metrics
- Authors: Irwin, Barry V W
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427944 , vital:72475 , https://www.researchgate.net/profile/Barry-Ir-win/publication/265121268_Network_Telescope_Metrics/links/58e23f70a6fdcc41bf973e69/Network-Telescope-Metrics.pdf
- Description: Network telescopes are a means of passive network monitoring, increasingly being used as part of a holistic network security program. One problem encountered by researchers in the sharing of the collected data form these systems. This is either due to the size of the data, or possibly a need to maintain the privacy of the Network address space being used for monitoring. This paper proposes a selection of metrics which can be used to communicate the most salient information contained in the data-set with other researchers, without the need to exchange or disclose the data-sets. Descriptive metrics for the sensor system are discussed along with numerical analysis data. The case for the use of graphical summary data is also presented.
- Full Text:
- Date Issued: 2012
- Authors: Irwin, Barry V W
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427944 , vital:72475 , https://www.researchgate.net/profile/Barry-Ir-win/publication/265121268_Network_Telescope_Metrics/links/58e23f70a6fdcc41bf973e69/Network-Telescope-Metrics.pdf
- Description: Network telescopes are a means of passive network monitoring, increasingly being used as part of a holistic network security program. One problem encountered by researchers in the sharing of the collected data form these systems. This is either due to the size of the data, or possibly a need to maintain the privacy of the Network address space being used for monitoring. This paper proposes a selection of metrics which can be used to communicate the most salient information contained in the data-set with other researchers, without the need to exchange or disclose the data-sets. Descriptive metrics for the sensor system are discussed along with numerical analysis data. The case for the use of graphical summary data is also presented.
- Full Text:
- Date Issued: 2012
Normandy: A Framework for Implementing High Speed Lexical Classification of Malicious URLs
- Egan, Shaun P, Irwin, Barry V W
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427958 , vital:72476 , https://www.researchgate.net/profile/Barry-Ir-win/publication/326224974_Normandy_A_Framework_for_Implementing_High_Speed_Lexical_Classification_of_Malicious_URLs/links/5b3f21074585150d2309dd50/Normandy-A-Framework-for-Implementing-High-Speed-Lexical-Classification-of-Malicious-URLs.pdf
- Description: Research has shown that it is possible to classify malicious URLs using state of the art techniques to train Artificial Neural Networks (ANN) using only lexical features of a URL. This has the advantage of being high speed and does not add any overhead to classifications as it does not require look-ups from external services. This paper discusses our method for implementing and testing a framework which automates the generation of these neural networks as well as testing involved in trying to optimize the performance of these ANNs.
- Full Text:
- Date Issued: 2012
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427958 , vital:72476 , https://www.researchgate.net/profile/Barry-Ir-win/publication/326224974_Normandy_A_Framework_for_Implementing_High_Speed_Lexical_Classification_of_Malicious_URLs/links/5b3f21074585150d2309dd50/Normandy-A-Framework-for-Implementing-High-Speed-Lexical-Classification-of-Malicious-URLs.pdf
- Description: Research has shown that it is possible to classify malicious URLs using state of the art techniques to train Artificial Neural Networks (ANN) using only lexical features of a URL. This has the advantage of being high speed and does not add any overhead to classifications as it does not require look-ups from external services. This paper discusses our method for implementing and testing a framework which automates the generation of these neural networks as well as testing involved in trying to optimize the performance of these ANNs.
- Full Text:
- Date Issued: 2012
Normative and institutional approaches to the protection of property rights of IDPs in Kenya's Rift Valley Province
- Authors: Juma, Laurence
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127464 , vital:36014 , https://doi.org/10.3366/ajicl.2012.0033
- Description: The post-election violence of 2008 which displaced about 600,000 people in six out of the eight provinces of Kenya1 has brought the plight of the internally displaced persons (IDPs) to the forefront of the national debate on politics and law. Transcending this debate is the sobering reality that inasmuch as the events of 2008 were catastrophic, they were a mere replay of the ethnically engineered political violence that Kenyans have had to endure before and after every major election since 1990.2
- Full Text: false
- Date Issued: 2012
- Authors: Juma, Laurence
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127464 , vital:36014 , https://doi.org/10.3366/ajicl.2012.0033
- Description: The post-election violence of 2008 which displaced about 600,000 people in six out of the eight provinces of Kenya1 has brought the plight of the internally displaced persons (IDPs) to the forefront of the national debate on politics and law. Transcending this debate is the sobering reality that inasmuch as the events of 2008 were catastrophic, they were a mere replay of the ethnically engineered political violence that Kenyans have had to endure before and after every major election since 1990.2
- Full Text: false
- Date Issued: 2012
Nothing but a mass of debris: urban evictions and the right of access to adequate housing in Kenya
- Authors: Juma, Laurence
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128425 , vital:36108 , http://www.scielo.org.za/scielo.php?script=sci_arttextamp;pid=S1996-20962012000200008amp;lng=enamp;nrm=iso
- Description: The article explores the opportunities that the new constitutional dispensation in Kenya has created for the protection against unlawful eviction of poor populations living in urban centres. It analyses the content of the right to accessible and adequate housing as provided for in article 43 of the Constitution of Kenya and articulated in various international instruments, and traces how this provision has been applied in the eviction cases that the Kenyan courts have decided. From this analysis, the article suggests that the new constitutional dispensation has opened up possibilities for rights enforcement that the courts as well as administrative organs should take advantage of. It also makes tangible suggestions on how to improve rights litigation in this regard, such as affirming the rights of access to courts and seeking further judicial oversight prior to any eviction and the promulgation of enabling legislation.
- Full Text:
- Date Issued: 2012
- Authors: Juma, Laurence
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128425 , vital:36108 , http://www.scielo.org.za/scielo.php?script=sci_arttextamp;pid=S1996-20962012000200008amp;lng=enamp;nrm=iso
- Description: The article explores the opportunities that the new constitutional dispensation in Kenya has created for the protection against unlawful eviction of poor populations living in urban centres. It analyses the content of the right to accessible and adequate housing as provided for in article 43 of the Constitution of Kenya and articulated in various international instruments, and traces how this provision has been applied in the eviction cases that the Kenyan courts have decided. From this analysis, the article suggests that the new constitutional dispensation has opened up possibilities for rights enforcement that the courts as well as administrative organs should take advantage of. It also makes tangible suggestions on how to improve rights litigation in this regard, such as affirming the rights of access to courts and seeking further judicial oversight prior to any eviction and the promulgation of enabling legislation.
- Full Text:
- Date Issued: 2012
Otoliths versus scales: evaluating the most suitable structure for ageing largemouth bass, Micropterus salmoides, in South Africa
- Taylor, Geraldine C, Weyl, Olaf L F
- Authors: Taylor, Geraldine C , Weyl, Olaf L F
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443907 , vital:74170 , https://doi.org/10.1080/15627020.2012.11407562
- Description: The suitability of scales for ageing Micropterus salmoides was determined by comparing the precision of growth zone counts on scales with those obtained from sectioned sagittal otoliths from a sample of 496 fish collected from Wriggleswade and Mankazana Impoundments in the Eastern Cape, South Africa. Otoliths (1.4% rejected) were more readable than scales (41.7% and 7.5% rejected) for Wriggleswade and Mankazana Impoundments respectively. Otolith readings were more precise (average percentage error (APE) = 13.6%; coefficient of variation (CV) = 15.8%) than scales (APE = 18.0%; CV = 21.9%) for the total sample. Growth zone counts between structures were not symmetrically distributed around the agreed ages (otolith age = scale age) of the fish from Wriggleswade Impoundment (Bowker’s test H2: χ2 = 136, d.f. = 27, P 0.05) and graphical comparison showed that scales tended to underestimate age, particularly for fish older than five years. Scales are therefore not suitable structures for ageing South African M. salmoides which may attain ages of up to 13 years.
- Full Text:
- Date Issued: 2012
- Authors: Taylor, Geraldine C , Weyl, Olaf L F
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443907 , vital:74170 , https://doi.org/10.1080/15627020.2012.11407562
- Description: The suitability of scales for ageing Micropterus salmoides was determined by comparing the precision of growth zone counts on scales with those obtained from sectioned sagittal otoliths from a sample of 496 fish collected from Wriggleswade and Mankazana Impoundments in the Eastern Cape, South Africa. Otoliths (1.4% rejected) were more readable than scales (41.7% and 7.5% rejected) for Wriggleswade and Mankazana Impoundments respectively. Otolith readings were more precise (average percentage error (APE) = 13.6%; coefficient of variation (CV) = 15.8%) than scales (APE = 18.0%; CV = 21.9%) for the total sample. Growth zone counts between structures were not symmetrically distributed around the agreed ages (otolith age = scale age) of the fish from Wriggleswade Impoundment (Bowker’s test H2: χ2 = 136, d.f. = 27, P 0.05) and graphical comparison showed that scales tended to underestimate age, particularly for fish older than five years. Scales are therefore not suitable structures for ageing South African M. salmoides which may attain ages of up to 13 years.
- Full Text:
- Date Issued: 2012
Oxovanadium (IV)-catalysed oxidation of dibenzothiophene and 4, 6-dimethyldibenzothiophene
- Ogunlaja, Adeniyi S, Chidawanyika, Wadzanai J U, Antunes, Edith M, Fernandes, Manuel A, Nyokong, Tebello, Torto, Nelson, Tshentu, Zenixole R
- Authors: Ogunlaja, Adeniyi S , Chidawanyika, Wadzanai J U , Antunes, Edith M , Fernandes, Manuel A , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246025 , vital:51429 , xlink:href="https://doi.org/10.1039/C2DT31433A"
- Description: The reaction between [VIVOSO4] and the tetradentate N2O2-donor Schiff base ligand, N,N-bis(o-hydroxybenzaldehyde)phenylenediamine (sal-HBPD), obtained by the condensation of salicylaldehyde and o-phenylenediamine in a molar ratio of 2 : 1 respectively, resulted in the formation of [VIVO(sal-HBPD)]. The molecular structure of [VIVO(sal-HBPD)] was determined by single crystal X-ray diffraction, and confirmed the distorted square pyramidal geometry of the complex with the N2O2 binding mode of the tetradentate ligand. The formation of the polymer-supported p[VIVO(sal-AHBPD)] proceeded via the nitrosation of sal-HBPD, followed by the reduction with hydrogen to form an amine group that was then linked to Merrifield beads followed by the reaction with [VIVOSO4]. XPS and EPR were used to confirm the presence of oxovanadium(IV) within the beads. The BET surface area and porosity of the heterogeneous catalyst p[VIVO(sal-AHBPD)] were found to be 6.9 m2 g−1 and 180.8 Å respectively. Microanalysis, TG, UV-Vis and FT-IR were used for further characterization of both [VIVO(sal-HBPD)] and p[VIVO(sal-AHBPD)]. Oxidation of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was investigated using [VIVO(sal-HBPD)] and p[VIVO(sal-AHBPD)] as catalysts. Progress for oxidation of these model compounds was monitored with a gas chromatograph fitted with a flame ionization detector. The oxidation products were characterized using gas chromatography-mass spectrometry, microanalysis and NMR. Dibenzothiophene sulfone (DBTO2) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) were found to be the main products of oxidation. Oxovanadium(IV) Schiff base microspherical beads, p[VIVO(sal-AHBPD)], were able to catalyse the oxidation of sulfur in dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) to a tune of 88.0% and 71.8% respectively after 3 h at 40 °C. These oxidation results show promise for potential application of this catalyst in the oxidative desulfurization of crude oils.
- Full Text:
- Date Issued: 2012
- Authors: Ogunlaja, Adeniyi S , Chidawanyika, Wadzanai J U , Antunes, Edith M , Fernandes, Manuel A , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246025 , vital:51429 , xlink:href="https://doi.org/10.1039/C2DT31433A"
- Description: The reaction between [VIVOSO4] and the tetradentate N2O2-donor Schiff base ligand, N,N-bis(o-hydroxybenzaldehyde)phenylenediamine (sal-HBPD), obtained by the condensation of salicylaldehyde and o-phenylenediamine in a molar ratio of 2 : 1 respectively, resulted in the formation of [VIVO(sal-HBPD)]. The molecular structure of [VIVO(sal-HBPD)] was determined by single crystal X-ray diffraction, and confirmed the distorted square pyramidal geometry of the complex with the N2O2 binding mode of the tetradentate ligand. The formation of the polymer-supported p[VIVO(sal-AHBPD)] proceeded via the nitrosation of sal-HBPD, followed by the reduction with hydrogen to form an amine group that was then linked to Merrifield beads followed by the reaction with [VIVOSO4]. XPS and EPR were used to confirm the presence of oxovanadium(IV) within the beads. The BET surface area and porosity of the heterogeneous catalyst p[VIVO(sal-AHBPD)] were found to be 6.9 m2 g−1 and 180.8 Å respectively. Microanalysis, TG, UV-Vis and FT-IR were used for further characterization of both [VIVO(sal-HBPD)] and p[VIVO(sal-AHBPD)]. Oxidation of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was investigated using [VIVO(sal-HBPD)] and p[VIVO(sal-AHBPD)] as catalysts. Progress for oxidation of these model compounds was monitored with a gas chromatograph fitted with a flame ionization detector. The oxidation products were characterized using gas chromatography-mass spectrometry, microanalysis and NMR. Dibenzothiophene sulfone (DBTO2) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) were found to be the main products of oxidation. Oxovanadium(IV) Schiff base microspherical beads, p[VIVO(sal-AHBPD)], were able to catalyse the oxidation of sulfur in dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) to a tune of 88.0% and 71.8% respectively after 3 h at 40 °C. These oxidation results show promise for potential application of this catalyst in the oxidative desulfurization of crude oils.
- Full Text:
- Date Issued: 2012
Parameter relationships in high-speed audio networks
- Chigwamba, Nyasha, Foss, Richard, Gurdan, Robby, Klinkradt, Bradley
- Authors: Chigwamba, Nyasha , Foss, Richard , Gurdan, Robby , Klinkradt, Bradley
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427027 , vital:72409 , https://www.aes.org/e-lib/browse.cfm?elib=16211
- Description: When related audio control parameters are distributed in many devices in a high-speed audio network, a means for centralizing remote control and monitoring is required. Changes in one parameter may need to affect other parameters. The XFN protocol enables management of distributed parameters. This paper focuses on how to group related parameters that are physically separated and provides a corresponding implementation using the protocol. A comprehensive grouping theory is presented.
- Full Text:
- Date Issued: 2012
- Authors: Chigwamba, Nyasha , Foss, Richard , Gurdan, Robby , Klinkradt, Bradley
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427027 , vital:72409 , https://www.aes.org/e-lib/browse.cfm?elib=16211
- Description: When related audio control parameters are distributed in many devices in a high-speed audio network, a means for centralizing remote control and monitoring is required. Changes in one parameter may need to affect other parameters. The XFN protocol enables management of distributed parameters. This paper focuses on how to group related parameters that are physically separated and provides a corresponding implementation using the protocol. A comprehensive grouping theory is presented.
- Full Text:
- Date Issued: 2012