A framework for DNS based detection and mitigation of malware infections on a network
- Stalmans, Etienne, Irwin, Barry V W
- Authors: Stalmans, Etienne , Irwin, Barry V W
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429827 , vital:72642 , 10.1109/ISSA.2011.6027531
- Description: Modern botnet trends have lead to the use of IP and domain fast-fluxing to avoid detection and increase resilience. These techniques bypass traditional detection systems such as blacklists and intrusion detection systems. The Domain Name Service (DNS) is one of the most prevalent protocols on modern networks and is essential for the correct operation of many network activities, including botnet activity. For this reason DNS forms the ideal candidate for monitoring, detecting and mit-igating botnet activity. In this paper a system placed at the network edge is developed with the capability to detect fast-flux domains using DNS queries. Multiple domain features were examined to determine which would be most effective in the classification of domains. This is achieved using a C5.0 decision tree classifier and Bayesian statistics, with positive samples being labeled as potentially malicious and nega-tive samples as legitimate domains. The system detects malicious do-main names with a high degree of accuracy, minimising the need for blacklists. Statistical methods, namely Naive Bayesian, Bayesian, Total Variation distance and Probability distribution are applied to detect mali-cious domain names. The detection techniques are tested against sample traffic and it is shown that malicious traffic can be detected with low false positive rates.
- Full Text:
- Date Issued: 2011
- Authors: Stalmans, Etienne , Irwin, Barry V W
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429827 , vital:72642 , 10.1109/ISSA.2011.6027531
- Description: Modern botnet trends have lead to the use of IP and domain fast-fluxing to avoid detection and increase resilience. These techniques bypass traditional detection systems such as blacklists and intrusion detection systems. The Domain Name Service (DNS) is one of the most prevalent protocols on modern networks and is essential for the correct operation of many network activities, including botnet activity. For this reason DNS forms the ideal candidate for monitoring, detecting and mit-igating botnet activity. In this paper a system placed at the network edge is developed with the capability to detect fast-flux domains using DNS queries. Multiple domain features were examined to determine which would be most effective in the classification of domains. This is achieved using a C5.0 decision tree classifier and Bayesian statistics, with positive samples being labeled as potentially malicious and nega-tive samples as legitimate domains. The system detects malicious do-main names with a high degree of accuracy, minimising the need for blacklists. Statistical methods, namely Naive Bayesian, Bayesian, Total Variation distance and Probability distribution are applied to detect mali-cious domain names. The detection techniques are tested against sample traffic and it is shown that malicious traffic can be detected with low false positive rates.
- Full Text:
- Date Issued: 2011
A Framework for the Management of Operator Policies and User Preferences for Service Compositions in the IP Multimedia Subsystem
- Tsietsi, Mosiuoa, Terzoli, Alfredo, Wells, George C
- Authors: Tsietsi, Mosiuoa , Terzoli, Alfredo , Wells, George C
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430680 , vital:72708 , https://ieeexplore.ieee.org/abstract/document/6032212
- Description: The IP Multimedia Subsystem (IMS) is a telecommunication middleware platform with robust service features that enables the delivery of a wide range of services to mobile network subscribers. Network operators are encouraged to develop services from service building blocks in order to avoid redundancies by re-using existing functionality. In this environ-ment, operators must be able to control the service execution chain in order to prevent undesirable interactions from occurring between indi-vidual building blocks. It is also in their interests to provide subscribers with personalisation options so that they can modify service composi-tions and define their own preferences for how they would like their ser-vices to behave during live sessions. This paper describes a solution for these challenges that involves the storage of service information in an XDMS and allows operator staff and subscribers to manage this in-formation using the XCAP protocol. The ETSI-defined XCAP applica-tion usage named simservs was chosen to demonstrate an application usage that can be used to create service compositions in XML format. A prototype is described that uses components of the open source Mo-bicents project to verify the suitability of the design. This work is part of a larger effort aimed at modeling interaction management in the IMS through the use of a service broker that is part of an extended IMS ser-vice layer (EISL). The service broker's functional and structural architec-ture have not yet been standardised.
- Full Text:
- Date Issued: 2011
- Authors: Tsietsi, Mosiuoa , Terzoli, Alfredo , Wells, George C
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430680 , vital:72708 , https://ieeexplore.ieee.org/abstract/document/6032212
- Description: The IP Multimedia Subsystem (IMS) is a telecommunication middleware platform with robust service features that enables the delivery of a wide range of services to mobile network subscribers. Network operators are encouraged to develop services from service building blocks in order to avoid redundancies by re-using existing functionality. In this environ-ment, operators must be able to control the service execution chain in order to prevent undesirable interactions from occurring between indi-vidual building blocks. It is also in their interests to provide subscribers with personalisation options so that they can modify service composi-tions and define their own preferences for how they would like their ser-vices to behave during live sessions. This paper describes a solution for these challenges that involves the storage of service information in an XDMS and allows operator staff and subscribers to manage this in-formation using the XCAP protocol. The ETSI-defined XCAP applica-tion usage named simservs was chosen to demonstrate an application usage that can be used to create service compositions in XML format. A prototype is described that uses components of the open source Mo-bicents project to verify the suitability of the design. This work is part of a larger effort aimed at modeling interaction management in the IMS through the use of a service broker that is part of an extended IMS ser-vice layer (EISL). The service broker's functional and structural architec-ture have not yet been standardised.
- Full Text:
- Date Issued: 2011
A research tool for analysing and monitoring the Extent to which Environmental issues are integrated into teachers’ lessons
- Authors: Nsubuga, Yvonne
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386447 , vital:68142 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122246"
- Description: South Africa enjoys strong policy support for the integration of environmental issues into school curricula. However, much doubt exists over the extent to which this has been converted into appropriate classroom practice at the majority of under-resourced rural schools in the country. This article reports on a study which piloted a research tool which can be used to analyse teachers’ lessons, with the aim of gaining insight into the extent to which they integrate natural resource management issues. The research tool was based on Bernstein’s concept of classification and consisted of five indicators of natural resource management integration into Life Sciences lessons. The study contributes to the design of research tools that can be used to analyse and monitor the integration of environmental issues into teachers’ lessons. It also provides some insight into the environmental content of a sample of Grade 10 Life Sciences lessons at four rural underresourced schools in the Eastern Cape.
- Full Text:
- Date Issued: 2011
- Authors: Nsubuga, Yvonne
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386447 , vital:68142 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122246"
- Description: South Africa enjoys strong policy support for the integration of environmental issues into school curricula. However, much doubt exists over the extent to which this has been converted into appropriate classroom practice at the majority of under-resourced rural schools in the country. This article reports on a study which piloted a research tool which can be used to analyse teachers’ lessons, with the aim of gaining insight into the extent to which they integrate natural resource management issues. The research tool was based on Bernstein’s concept of classification and consisted of five indicators of natural resource management integration into Life Sciences lessons. The study contributes to the design of research tools that can be used to analyse and monitor the integration of environmental issues into teachers’ lessons. It also provides some insight into the environmental content of a sample of Grade 10 Life Sciences lessons at four rural underresourced schools in the Eastern Cape.
- Full Text:
- Date Issued: 2011
A Search for Conjunctions at a Time of Direction-setting Review and Synthesis
- Authors: O'Donoghue, Rob B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387134 , vital:68209 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122240"
- Description: This journal reflects a diversity of environment and sustainability education research and viewpoints alongside two synthesis papers. Read as a whole and within a widely held ideal that diversity reflects resilience, the environment and education for sustainable development landscape in Africa might be said to be healthy and proliferating. But read against the pressure to produce tangible evidence of change on an African landscape of persistent climate variation and poverty, along with a widening gap between rich and poor, the picture remains challenging. These contrasting readings are notable at a time when we are looking towards the Association for the Development of Education in Africa (ADEA) Triennial in February, 2012, the Rio+20 Earth Summit in June 2012 and our own EEASA +30 conference in September 2012. The UN Decade of Education for Sustainable Development is characterised by a proliferation of education imperatives. These emerged as modern education in response to the issues of the day and now a modernity in deepening crisis.
- Full Text:
- Date Issued: 2011
- Authors: O'Donoghue, Rob B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387134 , vital:68209 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122240"
- Description: This journal reflects a diversity of environment and sustainability education research and viewpoints alongside two synthesis papers. Read as a whole and within a widely held ideal that diversity reflects resilience, the environment and education for sustainable development landscape in Africa might be said to be healthy and proliferating. But read against the pressure to produce tangible evidence of change on an African landscape of persistent climate variation and poverty, along with a widening gap between rich and poor, the picture remains challenging. These contrasting readings are notable at a time when we are looking towards the Association for the Development of Education in Africa (ADEA) Triennial in February, 2012, the Rio+20 Earth Summit in June 2012 and our own EEASA +30 conference in September 2012. The UN Decade of Education for Sustainable Development is characterised by a proliferation of education imperatives. These emerged as modern education in response to the issues of the day and now a modernity in deepening crisis.
- Full Text:
- Date Issued: 2011
A white man in exile
- Authors: Krueger, Anton
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229459 , vital:49677 , xlink:href="https://doi.org/10.1080/10137548.2011.636974"
- Description: This article explores intersections between understandings of masculinity and nationalism. Etymologically, ‘patriotism’ refers to a love for a fatherland and a patriarchal order; it includes notions of loyalty, honour and a range of qualities often associated with conceptions of masculinity. But if gender remains fixed to these normative constructions, what happens to one’s sense of masculine identity when the national state changes? My interest lies in exploring how white South African men have been repositioned in terms of a shift in their gendered identification, with a reflection on the possibly tragic consequences of maintaining an overly rigid gender role identification. As long as masculinity is embedded within nationalism, it will be caught up within a defensive reactive mode which can turn self-destructive. In order to explore these ideas the article employs as its central metaphor the character of Dawid Olivier, who is the protagonist of Athol Fugard’s Sorrows and Rejoicings (2002).
- Full Text:
- Date Issued: 2011
- Authors: Krueger, Anton
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229459 , vital:49677 , xlink:href="https://doi.org/10.1080/10137548.2011.636974"
- Description: This article explores intersections between understandings of masculinity and nationalism. Etymologically, ‘patriotism’ refers to a love for a fatherland and a patriarchal order; it includes notions of loyalty, honour and a range of qualities often associated with conceptions of masculinity. But if gender remains fixed to these normative constructions, what happens to one’s sense of masculine identity when the national state changes? My interest lies in exploring how white South African men have been repositioned in terms of a shift in their gendered identification, with a reflection on the possibly tragic consequences of maintaining an overly rigid gender role identification. As long as masculinity is embedded within nationalism, it will be caught up within a defensive reactive mode which can turn self-destructive. In order to explore these ideas the article employs as its central metaphor the character of Dawid Olivier, who is the protagonist of Athol Fugard’s Sorrows and Rejoicings (2002).
- Full Text:
- Date Issued: 2011
Adoption, use and perception of Australian acacias around the world
- Kull, Christian A, Shackleton, Charlie M, Cunningham, Peter J, Ducatillon, Catherine, Dufour-Dror, Jean-Mark, Esler, Karen J, Friday, James B, Gouveia, António C, Griffin, A R, Marchante, Elizabete, Midgley, Steven J, Pauchard, Aníbal, Rangan, Haripriya, Richardson, David M, Rinaudo, Tony, Tassin, Jacques, Urgenson, Lauren S, van Maltitz, Graham P, Zenni, Rafael D, Zylstra, Matthew J
- Authors: Kull, Christian A , Shackleton, Charlie M , Cunningham, Peter J , Ducatillon, Catherine , Dufour-Dror, Jean-Mark , Esler, Karen J , Friday, James B , Gouveia, António C , Griffin, A R , Marchante, Elizabete , Midgley, Steven J , Pauchard, Aníbal , Rangan, Haripriya , Richardson, David M , Rinaudo, Tony , Tassin, Jacques , Urgenson, Lauren S , van Maltitz, Graham P , Zenni, Rafael D , Zylstra, Matthew J
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182149 , vital:43804 , xlink:href="https://doi.org/10.1111/j.1472-4642.2011.00783.x"
- Description: To examine the different uses and perceptions of introduced Australian acacias (wattles; Acacia subgenus Phyllodineae) by rural households and communities. Eighteen landscape-scale case studies around the world, in Vietnam, India, Réunion, Madagascar, South Africa, Congo, Niger, Ethiopia, Israel, France, Portugal, Brazil, Chile, Dominican Republic and Hawai‘i. Qualitative comparison of case studies, based on questionnaire sent to network of acacia researchers. Information based on individual knowledge of local experts, published and unpublished sources. We propose a conceptual model to explain current uses and perceptions of introduced acacias. It highlights historically and geographically contingent processes, including economic development, environmental discourses, political context, and local or regional needs. Four main groupings of case studies were united by similar patterns: (1) poor communities benefiting from targeted agroforestry projects; (2) places where residents, generally poor, take advantage of a valuable resource already present in their landscape via plantation and/or invasion; (3) regions of small and mid-scale tree farmers participating in the forestry industry; and (4) a number of high-income communities dealing with the legacies of former or niche use of introduced acacia in a context of increased concern over biodiversity and ecosystem services. Economic conditions play a key role shaping acacia use. Poorer communities rely strongly on acacias (often in, or escaped from, formal plantations) for household needs and, sometimes, for income. Middle-income regions more typically host private farm investments in acacia woodlots for commercialization. Efforts at control of invasive acacias must take care to not adversely impact poor dependent communities.
- Full Text:
- Date Issued: 2011
- Authors: Kull, Christian A , Shackleton, Charlie M , Cunningham, Peter J , Ducatillon, Catherine , Dufour-Dror, Jean-Mark , Esler, Karen J , Friday, James B , Gouveia, António C , Griffin, A R , Marchante, Elizabete , Midgley, Steven J , Pauchard, Aníbal , Rangan, Haripriya , Richardson, David M , Rinaudo, Tony , Tassin, Jacques , Urgenson, Lauren S , van Maltitz, Graham P , Zenni, Rafael D , Zylstra, Matthew J
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182149 , vital:43804 , xlink:href="https://doi.org/10.1111/j.1472-4642.2011.00783.x"
- Description: To examine the different uses and perceptions of introduced Australian acacias (wattles; Acacia subgenus Phyllodineae) by rural households and communities. Eighteen landscape-scale case studies around the world, in Vietnam, India, Réunion, Madagascar, South Africa, Congo, Niger, Ethiopia, Israel, France, Portugal, Brazil, Chile, Dominican Republic and Hawai‘i. Qualitative comparison of case studies, based on questionnaire sent to network of acacia researchers. Information based on individual knowledge of local experts, published and unpublished sources. We propose a conceptual model to explain current uses and perceptions of introduced acacias. It highlights historically and geographically contingent processes, including economic development, environmental discourses, political context, and local or regional needs. Four main groupings of case studies were united by similar patterns: (1) poor communities benefiting from targeted agroforestry projects; (2) places where residents, generally poor, take advantage of a valuable resource already present in their landscape via plantation and/or invasion; (3) regions of small and mid-scale tree farmers participating in the forestry industry; and (4) a number of high-income communities dealing with the legacies of former or niche use of introduced acacia in a context of increased concern over biodiversity and ecosystem services. Economic conditions play a key role shaping acacia use. Poorer communities rely strongly on acacias (often in, or escaped from, formal plantations) for household needs and, sometimes, for income. Middle-income regions more typically host private farm investments in acacia woodlots for commercialization. Efforts at control of invasive acacias must take care to not adversely impact poor dependent communities.
- Full Text:
- Date Issued: 2011
African Languages And ICT Education
- Dalvit, Lorenzo, Murray, Sarah, Terzoli, Alfredo
- Authors: Dalvit, Lorenzo , Murray, Sarah , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431166 , vital:72750 , https://www.scitepress.org/Papers/2011/33507/33507.pdf
- Description: In South Africa, English plays a dominant role compared to African lan-guages in empowering domain. Better access to Education through the use of African languages is an object of heated debate. This paper shows that an intervention involving the use of an African language in the domain of ICT Education can change the attitudes of Black universi-ty students. The methodology used included a survey with preliminary and follow-up questionnaires and interviews and an intervention involv-ing the use of localised software and of an on-line glossary of computer terms translated, explained and exemplified in an African language (isiXhosa). This experience increased the support for the use of African languages as additional LoLT, even in the English-dominated field of study of Computer Science. This is an initial step towards promoting linguistic equality between English and African languages and social equality between their speakers.
- Full Text:
- Date Issued: 2011
- Authors: Dalvit, Lorenzo , Murray, Sarah , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431166 , vital:72750 , https://www.scitepress.org/Papers/2011/33507/33507.pdf
- Description: In South Africa, English plays a dominant role compared to African lan-guages in empowering domain. Better access to Education through the use of African languages is an object of heated debate. This paper shows that an intervention involving the use of an African language in the domain of ICT Education can change the attitudes of Black universi-ty students. The methodology used included a survey with preliminary and follow-up questionnaires and interviews and an intervention involv-ing the use of localised software and of an on-line glossary of computer terms translated, explained and exemplified in an African language (isiXhosa). This experience increased the support for the use of African languages as additional LoLT, even in the English-dominated field of study of Computer Science. This is an initial step towards promoting linguistic equality between English and African languages and social equality between their speakers.
- Full Text:
- Date Issued: 2011
An evaluation of lightweight classification methods for identifying malicious URLs
- Egan, Shaun P, Irwin, Barry V W
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429839 , vital:72644 , 10.1109/ISSA.2011.6027532
- Description: Recent research has shown that it is possible to identify malicious URLs through lexical analysis of their URL structures alone. This paper intends to explore the effectiveness of these lightweight classification algorithms when working with large real world datasets including lists of malicious URLs obtained from Phishtank as well as largely filtered be-nign URLs obtained from proxy traffic logs. Lightweight algorithms are defined as methods by which URLs are analysed that do not use exter-nal sources of information such as WHOIS lookups, blacklist lookups and content analysis. These parameters include URL length, number of delimiters as well as the number of traversals through the directory structure and are used throughout much of the research in the para-digm of lightweight classification. Methods which include external sources of information are often called fully featured classifications and have been shown to be only slightly more effective than a purely lexical analysis when considering both false-positives and false-negatives. This distinction allows these algorithms to be run client side without the introduction of additional latency, but still providing a high level of accu-racy through the use of modern techniques in training classifiers. Anal-ysis of this type will also be useful in an incident response analysis where large numbers of URLs need to be filtered for potentially mali-cious URLs as an initial step in information gathering as well as end us-er implementations such as browser extensions which could help pro-tect the user from following potentially malicious links. Both AROW and CW classifier update methods will be used as prototype implementa-tions and their effectiveness will be compared to fully featured analysis results. These methods are interesting because they are able to train on any labelled data, including instances in which their prediction is cor-rect, allowing them to build a confidence in specific lexical features. This makes it possible for them to be trained using noisy input data, making them ideal for real world applications such as link filtering and information gathering.
- Full Text:
- Date Issued: 2011
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429839 , vital:72644 , 10.1109/ISSA.2011.6027532
- Description: Recent research has shown that it is possible to identify malicious URLs through lexical analysis of their URL structures alone. This paper intends to explore the effectiveness of these lightweight classification algorithms when working with large real world datasets including lists of malicious URLs obtained from Phishtank as well as largely filtered be-nign URLs obtained from proxy traffic logs. Lightweight algorithms are defined as methods by which URLs are analysed that do not use exter-nal sources of information such as WHOIS lookups, blacklist lookups and content analysis. These parameters include URL length, number of delimiters as well as the number of traversals through the directory structure and are used throughout much of the research in the para-digm of lightweight classification. Methods which include external sources of information are often called fully featured classifications and have been shown to be only slightly more effective than a purely lexical analysis when considering both false-positives and false-negatives. This distinction allows these algorithms to be run client side without the introduction of additional latency, but still providing a high level of accu-racy through the use of modern techniques in training classifiers. Anal-ysis of this type will also be useful in an incident response analysis where large numbers of URLs need to be filtered for potentially mali-cious URLs as an initial step in information gathering as well as end us-er implementations such as browser extensions which could help pro-tect the user from following potentially malicious links. Both AROW and CW classifier update methods will be used as prototype implementa-tions and their effectiveness will be compared to fully featured analysis results. These methods are interesting because they are able to train on any labelled data, including instances in which their prediction is cor-rect, allowing them to build a confidence in specific lexical features. This makes it possible for them to be trained using noisy input data, making them ideal for real world applications such as link filtering and information gathering.
- Full Text:
- Date Issued: 2011
Being moved by a way the world is not
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
Comparative behavior of conjugates of tantalum phthalocyanines with gold nanoparticles or single walled carbon nanotubes towards bisphenol A electrocatalysis
- Chauke, Vongani P, Antunes, Edith M, Nyokong, Tebello
- Authors: Chauke, Vongani P , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247152 , vital:51551 , xlink:href="https://doi.org/10.1016/j.jelechem.2011.06.019"
- Description: The characterization of tantalum phthalocyanine conjugates with gold nanoparticles and single wall carbon nanotubes as well as their electrocatalytic oxidation of bisphenol A is hereby presented. The formation of the conjugates was confirmed by X-ray diffraction and transmission electron microscope techniques. Single walled carbon nanotube conjugates of TaPc complexes showed the best catalysis as well as less passivation for bisphenol A detection and significant recovery of ∼98% compared to gold nanoparticle conjugates.
- Full Text:
- Date Issued: 2011
- Authors: Chauke, Vongani P , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247152 , vital:51551 , xlink:href="https://doi.org/10.1016/j.jelechem.2011.06.019"
- Description: The characterization of tantalum phthalocyanine conjugates with gold nanoparticles and single wall carbon nanotubes as well as their electrocatalytic oxidation of bisphenol A is hereby presented. The formation of the conjugates was confirmed by X-ray diffraction and transmission electron microscope techniques. Single walled carbon nanotube conjugates of TaPc complexes showed the best catalysis as well as less passivation for bisphenol A detection and significant recovery of ∼98% compared to gold nanoparticle conjugates.
- Full Text:
- Date Issued: 2011
Conjugates of low-symmetry Ge, Sn and Ti carboxy phthalocyanines with glutathione caped gold nanoparticles
- Masilela, Nkosiphile, Nyokong, Tebello
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247003 , vital:51536 , xlink:href="https://doi.org/10.1016/j.jphotochem.2011.08.009"
- Description: This work reports on conjugation of low symmetry Ge (GeMCPc), Ti (TiMCPc) and Sn (SnMCPc) carboxy phthalocyanines with glutathione capped gold nanoparticles (GSH-AuNPs). The photophysical behaviour of the novel phthalocyanines–GSH-AuNPs conjugate was investigated and compared to the monocarboxy Pcs and to the mixture of Pc with GSH-AuNPs without a chemical bond. Blue shifting of Q band of the phthalocyanines was observed on linking to GSH-AuNPs. An improvement in triplet lifetimes was obtained for all the MPcs–GSH-AuNPs-linked conjugates compared to the MPcs alone. The highest triplet quantum yield of 0.75 and the longest triplet lifetime of 130 μs were obtained for the GeMCPc–GSH-AuNPs-linked conjugate. Fluorescence quantum yields and lifetimes were low for the conjugates due to quenching by the nanoparticles.
- Full Text:
- Date Issued: 2011
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247003 , vital:51536 , xlink:href="https://doi.org/10.1016/j.jphotochem.2011.08.009"
- Description: This work reports on conjugation of low symmetry Ge (GeMCPc), Ti (TiMCPc) and Sn (SnMCPc) carboxy phthalocyanines with glutathione capped gold nanoparticles (GSH-AuNPs). The photophysical behaviour of the novel phthalocyanines–GSH-AuNPs conjugate was investigated and compared to the monocarboxy Pcs and to the mixture of Pc with GSH-AuNPs without a chemical bond. Blue shifting of Q band of the phthalocyanines was observed on linking to GSH-AuNPs. An improvement in triplet lifetimes was obtained for all the MPcs–GSH-AuNPs-linked conjugates compared to the MPcs alone. The highest triplet quantum yield of 0.75 and the longest triplet lifetime of 130 μs were obtained for the GeMCPc–GSH-AuNPs-linked conjugate. Fluorescence quantum yields and lifetimes were low for the conjugates due to quenching by the nanoparticles.
- Full Text:
- Date Issued: 2011
Cyclic voltammetry and spectroelectrochemistry of a novel manganese phthalocyanine substituted with hexynyl groups
- Quinton, Damien, Antunes, Edith M, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Quinton, Damien , Antunes, Edith M , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248450 , vital:51687 , xlink:href="https://doi.org/10.1016/j.inoche.2010.11.029"
- Description: We report here on the synthesis of a new manganese phthalocyanine complex, namely Mn tetrakis(5-hexyn-oxy) phthalocyanine (3), specifically designed to possess an alkyne moiety for its potential use in controlled immobilization on electrodes via the so called “click” chemistry reaction. The electrochemical activity of complex 3 was investigated by cyclic voltammetry and the nature of the observed redox couples was elucidated by spectroelectrochemistry. This work has also shown that the reduction of Mn(III)Pc complex to Mn(II)Pc is accompanied by the formation of MnPc μ-oxo species. Further reduction results in the formation of Mn(II)Pc(− 3) rather than Mn(I)Pc(− 2).
- Full Text:
- Date Issued: 2011
- Authors: Quinton, Damien , Antunes, Edith M , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248450 , vital:51687 , xlink:href="https://doi.org/10.1016/j.inoche.2010.11.029"
- Description: We report here on the synthesis of a new manganese phthalocyanine complex, namely Mn tetrakis(5-hexyn-oxy) phthalocyanine (3), specifically designed to possess an alkyne moiety for its potential use in controlled immobilization on electrodes via the so called “click” chemistry reaction. The electrochemical activity of complex 3 was investigated by cyclic voltammetry and the nature of the observed redox couples was elucidated by spectroelectrochemistry. This work has also shown that the reduction of Mn(III)Pc complex to Mn(II)Pc is accompanied by the formation of MnPc μ-oxo species. Further reduction results in the formation of Mn(II)Pc(− 3) rather than Mn(I)Pc(− 2).
- Full Text:
- Date Issued: 2011
Development of an ICT road map for eservices in rural areas
- Jere, Norbert R, Thinyane, Mamello, Terzoli, Alfredo
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430695 , vital:72709 , https://ieeexplore.ieee.org/abstract/document/6144217
- Description: ICTs, driven by the convergence of computers, telecommunications and traditional media, are crucial for the knowledge-based economy of the future. The rapid technological changes have resulted in different ideas being suggested for the expected ICT applications. As a result, different e-Service applications have being developed as a way to fos-ter ICT developments. However, ICT applications deployed at the mo-ment may not be able to sustain the rural communities in maybe 10 years or more to come. The paper considers the past, analyzes the present and conduct surveys to gain insight into the future. Based on all of this information, the research tries to provide an ICT road map for what is to come. What kind of applications can we develop now to cater for the technological changes, so that the ICT applications developed today would still be compatible with those developed in years to come? The Siyakhula Living Lab (SLL) is used as the case study in this paper and some interviews and literature review are done to get different ide-as on the future of ICTs.
- Full Text:
- Date Issued: 2011
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430695 , vital:72709 , https://ieeexplore.ieee.org/abstract/document/6144217
- Description: ICTs, driven by the convergence of computers, telecommunications and traditional media, are crucial for the knowledge-based economy of the future. The rapid technological changes have resulted in different ideas being suggested for the expected ICT applications. As a result, different e-Service applications have being developed as a way to fos-ter ICT developments. However, ICT applications deployed at the mo-ment may not be able to sustain the rural communities in maybe 10 years or more to come. The paper considers the past, analyzes the present and conduct surveys to gain insight into the future. Based on all of this information, the research tries to provide an ICT road map for what is to come. What kind of applications can we develop now to cater for the technological changes, so that the ICT applications developed today would still be compatible with those developed in years to come? The Siyakhula Living Lab (SLL) is used as the case study in this paper and some interviews and literature review are done to get different ide-as on the future of ICTs.
- Full Text:
- Date Issued: 2011
Development of an Interactive Real-Time Negotiation Module for an E-commerce Platform
- Jere, Norbert R, Thinyane, Mamello, Terzoli, Alfredo
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430742 , vital:72712 , https://ieeexplore.ieee.org/abstract/document/5954490
- Description: With developments in the Internet and Web-based technologies, dis-tinctions between traditional markets and the global electronic market-place-such as business capital size, are gradually being narrowed down. It is recognized that in the Information Age, e-Commerce is a powerful tool for economic growth of developing countries. While there are indications of e-Commerce patronage among large firms in devel-oping countries, there seems to be little and negligible use of the Inter-net for commerce among small and medium sized firms. However, many of these e-Commerce projects in marginalized areas fail as a re-sult of lack of the required resources to support ICTs. Different ways have been suggested for marketing products online and to create cus-tomer loyalty. This paper discusses a marketing and customer loyalty strategy through a real-time interactive negotiation application, aimed at improving the existing e-Commerce platform. The e-Commerce platform has been deployed as part of the Siyakhula Living Lab ICTD project which is undertaken for the Dwesa community in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2011
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430742 , vital:72712 , https://ieeexplore.ieee.org/abstract/document/5954490
- Description: With developments in the Internet and Web-based technologies, dis-tinctions between traditional markets and the global electronic market-place-such as business capital size, are gradually being narrowed down. It is recognized that in the Information Age, e-Commerce is a powerful tool for economic growth of developing countries. While there are indications of e-Commerce patronage among large firms in devel-oping countries, there seems to be little and negligible use of the Inter-net for commerce among small and medium sized firms. However, many of these e-Commerce projects in marginalized areas fail as a re-sult of lack of the required resources to support ICTs. Different ways have been suggested for marketing products online and to create cus-tomer loyalty. This paper discusses a marketing and customer loyalty strategy through a real-time interactive negotiation application, aimed at improving the existing e-Commerce platform. The e-Commerce platform has been deployed as part of the Siyakhula Living Lab ICTD project which is undertaken for the Dwesa community in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2011
Drug transport mechanisms from carbopol/eudragit verapamil sustained-release tablets
- Khamanga, Sandile M, Walker, Roderick B
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184801 , vital:44273 , xlink:href="https://doi.org/10.14227/dt180311p30"
- Description: The objectives of this study were to compare dissolution profiles of a verapamil (VRP) formulation manufactured inhouse and Isoptin SR using USP Apparatus 2 and 3 and to elucidate drug release kinetics of these dosage forms. Eudragit NE 30D (ethyl acrylate–methyl methacrylate copolymer in a 2:1 ratio) aqueous dispersion was used as a granulating binder for the manufacture of VRP mini-matrix sustained-release tablets. The wet granulation process was performed to prepare free-flowing granules that were blended with Carbopol. The tablets were manufactured using a single-punch press by compression of the granules with magnesium stearate as a lubricant. Drug release was determined in phosphate buffer solution using USP Apparatus 2 and 3. Dissolution data were fitted to zero- and first-order models; in addition, the kinetic data were determined by evaluation of Higuchi release kinetics. The mechanism of drug release was established using the Korsmeyer–Peppas model. In general, all tablets showed high mechanical resistance with less than 1% friability. There was no significant difference between the dissolution profiles of the formulation manufactured in-house and the commercially available product. The release mechanism of the formulated and marketed products was controlled by anomalous non-Fickian diffusion. VRP release was prolonged for 12 h indicating the usefulness of the formulation as a twice-daily dosage form. The mechanism of drug release for the dosage forms was unaffected by the choice of apparatus.
- Full Text:
- Date Issued: 2011
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184801 , vital:44273 , xlink:href="https://doi.org/10.14227/dt180311p30"
- Description: The objectives of this study were to compare dissolution profiles of a verapamil (VRP) formulation manufactured inhouse and Isoptin SR using USP Apparatus 2 and 3 and to elucidate drug release kinetics of these dosage forms. Eudragit NE 30D (ethyl acrylate–methyl methacrylate copolymer in a 2:1 ratio) aqueous dispersion was used as a granulating binder for the manufacture of VRP mini-matrix sustained-release tablets. The wet granulation process was performed to prepare free-flowing granules that were blended with Carbopol. The tablets were manufactured using a single-punch press by compression of the granules with magnesium stearate as a lubricant. Drug release was determined in phosphate buffer solution using USP Apparatus 2 and 3. Dissolution data were fitted to zero- and first-order models; in addition, the kinetic data were determined by evaluation of Higuchi release kinetics. The mechanism of drug release was established using the Korsmeyer–Peppas model. In general, all tablets showed high mechanical resistance with less than 1% friability. There was no significant difference between the dissolution profiles of the formulation manufactured in-house and the commercially available product. The release mechanism of the formulated and marketed products was controlled by anomalous non-Fickian diffusion. VRP release was prolonged for 12 h indicating the usefulness of the formulation as a twice-daily dosage form. The mechanism of drug release for the dosage forms was unaffected by the choice of apparatus.
- Full Text:
- Date Issued: 2011
Electrochemical behavior of phthalocyanines containing high oxidation state central metals
- Chauke, Vongani, Arslanoglu, Yasin, Nyokong, Tebello
- Authors: Chauke, Vongani , Arslanoglu, Yasin , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247111 , vital:51547 , xlink:href="https://doi.org/10.1016/j.poly.2011.05.028"
- Description: The syntheses of 2,(3)-(peripheral) and 1,(4)-(non-peripheral) (2-mercaptopyridine)phthalocyanine complexes of titanium(IV) oxide (5a and 6a, respectively), vanadium(IV) oxide (7a and 8a, respectively) and tantalum(V) hydroxide (9a, peripheral only) and their electrochemical characterization are presented in this report. Their electrochemistry is compared to that of thiophenyl and thiobenzyl substituted derivatives. The non-peripherally substituted complexes are more difficult to reduce than peripherally substituted derivatives. In addition, the mercaptopyridine substituted derivatives are more difficult to reduce compared to benzylmercapto and phenylmercapto derivatives, and aryl easier reduce than alkyl substitution. Spectroelectrochemistry of the complexes confirmed metal and ring redox processes for TaPc and TiPc derivatives and ring based processes only for VPc complexes.
- Full Text:
- Date Issued: 2011
- Authors: Chauke, Vongani , Arslanoglu, Yasin , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247111 , vital:51547 , xlink:href="https://doi.org/10.1016/j.poly.2011.05.028"
- Description: The syntheses of 2,(3)-(peripheral) and 1,(4)-(non-peripheral) (2-mercaptopyridine)phthalocyanine complexes of titanium(IV) oxide (5a and 6a, respectively), vanadium(IV) oxide (7a and 8a, respectively) and tantalum(V) hydroxide (9a, peripheral only) and their electrochemical characterization are presented in this report. Their electrochemistry is compared to that of thiophenyl and thiobenzyl substituted derivatives. The non-peripherally substituted complexes are more difficult to reduce than peripherally substituted derivatives. In addition, the mercaptopyridine substituted derivatives are more difficult to reduce compared to benzylmercapto and phenylmercapto derivatives, and aryl easier reduce than alkyl substitution. Spectroelectrochemistry of the complexes confirmed metal and ring redox processes for TaPc and TiPc derivatives and ring based processes only for VPc complexes.
- Full Text:
- Date Issued: 2011
Electrochemical, microscopic and spectroscopic characterization of benzene diamine functionalized single walled carbon nanotube-cobalt (II) tetracarboxy-phthalocyanine conjugates
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247859 , vital:51624 , xlink:href="https://doi.org/10.1016/j.jcis.2010.10.057"
- Description: In this paper we report on the synthesis and characterization of 1,4-benzene diamine (BDA) functionalized single walled carbon nanotubes linked to cobalt (II) tetracarboxy-phthalocyanine. The characterization of the conjugate was through UV–vis, FTIR and X-ray diffraction (XRD) spectroscopies and by transmission electron microscope (TEM) and electrochemical methods. The conjugate is used for the electrochemical characterization of diuron. The catalytic rate constant for diuron was 4.4 × 103 M−1 s−1 and the apparent electron transfer rate constant was 18.5 × 10−6 cm s−1. The linear dynamic range was 1.0 × 10−5–2.0 × 10−4 M, with a sensitivity of ∼0.42 A mol−1L cm−2 and a limit of detection of 0.18 μM using the 3δ notation.
- Full Text:
- Date Issued: 2011
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247859 , vital:51624 , xlink:href="https://doi.org/10.1016/j.jcis.2010.10.057"
- Description: In this paper we report on the synthesis and characterization of 1,4-benzene diamine (BDA) functionalized single walled carbon nanotubes linked to cobalt (II) tetracarboxy-phthalocyanine. The characterization of the conjugate was through UV–vis, FTIR and X-ray diffraction (XRD) spectroscopies and by transmission electron microscope (TEM) and electrochemical methods. The conjugate is used for the electrochemical characterization of diuron. The catalytic rate constant for diuron was 4.4 × 103 M−1 s−1 and the apparent electron transfer rate constant was 18.5 × 10−6 cm s−1. The linear dynamic range was 1.0 × 10−5–2.0 × 10−4 M, with a sensitivity of ∼0.42 A mol−1L cm−2 and a limit of detection of 0.18 μM using the 3δ notation.
- Full Text:
- Date Issued: 2011
Electrooxidation of Chlorophenols Catalyzed by Nickel Octadecylphthalocyanine Adsorbed on Single‐Walled Carbon Nanotubes
- Khene, Samson, Nyokong, Tebello
- Authors: Khene, Samson , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247198 , vital:51555 , xlink:href="https://doi.org/10.1002/elan.201100155"
- Description: We described the synthesis of nickel octadecylphthalocyanine (NiPc(C10H21)8), followed by its adsorption on single-walled carbon nanotubes (SWCNT) to form SWCNT-NiPc(C10H21)8 conjugates. SWCNT-NiPc(C10H21)8 was used to modify a glassy carbon electrode (GCE) and for the electrooxidation of 4-chlorophenol and 2,4-dichlorophenol. The SWCNT and NiPc(C10H21)8 have a synergistic effect on each other in terms of improving electrocatalysis for the detection of chlorophenols. The stability of the electrode improved in the presence of NiPc(C10H21)8 or NiPc compared to the bare GCE. The presence of SWCNT improves the electrocatalytic behaviour of NiPc(C10H21)8 but not of unsubstituted NiPc. All modified electrodes showed improved stability towards the detection of 2,4-dichlorophenol. The best stability for 4-CP detection was observed in the presence of SWCNT for NiPc(C10H21)8.
- Full Text:
- Date Issued: 2011
- Authors: Khene, Samson , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247198 , vital:51555 , xlink:href="https://doi.org/10.1002/elan.201100155"
- Description: We described the synthesis of nickel octadecylphthalocyanine (NiPc(C10H21)8), followed by its adsorption on single-walled carbon nanotubes (SWCNT) to form SWCNT-NiPc(C10H21)8 conjugates. SWCNT-NiPc(C10H21)8 was used to modify a glassy carbon electrode (GCE) and for the electrooxidation of 4-chlorophenol and 2,4-dichlorophenol. The SWCNT and NiPc(C10H21)8 have a synergistic effect on each other in terms of improving electrocatalysis for the detection of chlorophenols. The stability of the electrode improved in the presence of NiPc(C10H21)8 or NiPc compared to the bare GCE. The presence of SWCNT improves the electrocatalytic behaviour of NiPc(C10H21)8 but not of unsubstituted NiPc. All modified electrodes showed improved stability towards the detection of 2,4-dichlorophenol. The best stability for 4-CP detection was observed in the presence of SWCNT for NiPc(C10H21)8.
- Full Text:
- Date Issued: 2011
Elizabeth Costello and the Biography of the Moral Philosopher
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275635 , vital:55065 , xlink:href="https://doi.org/10.1111/j.1540-6245.2011.01462.x"
- Description: Imagine someone who informs you that her conversion to vegetarianism began when she read Charlotte's Web or viewed the film Babe. Both stories invite the reader to celebrate the events surrounding a pig being saved from the butcher. What kind of role would her spectatorship of this book or film have played in her conversion? It is perhaps improbable to suspect that she would have undergone this kind of extreme moral conversion solely on the basis of her engagement with one of these fictions; perhaps more likely is the scenario in which her engagement was only one part of a lengthy process of her moral change of mind. In any event, it is certainly possible that our imagined vegetarian would see her encounter with Charlotte's Web or Babe as playing a justificatory role in her conversion. In looking back at her conversion, she might say something like this: “I know that I was young and impressionable, but the way in which the book (or film) made me feel about its characters moved me to further reflect upon animals and the animal industry, and I now realize that it was right to do so.” On her own view, at least, her spectatorship motivated and warranted her taking the further steps that ultimately led to her conversion. If she is right, then fictional narratives can possess—to at least some degree—what Raimond Gaita refers to as an ethical “authority.”
- Full Text:
- Date Issued: 2011
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275635 , vital:55065 , xlink:href="https://doi.org/10.1111/j.1540-6245.2011.01462.x"
- Description: Imagine someone who informs you that her conversion to vegetarianism began when she read Charlotte's Web or viewed the film Babe. Both stories invite the reader to celebrate the events surrounding a pig being saved from the butcher. What kind of role would her spectatorship of this book or film have played in her conversion? It is perhaps improbable to suspect that she would have undergone this kind of extreme moral conversion solely on the basis of her engagement with one of these fictions; perhaps more likely is the scenario in which her engagement was only one part of a lengthy process of her moral change of mind. In any event, it is certainly possible that our imagined vegetarian would see her encounter with Charlotte's Web or Babe as playing a justificatory role in her conversion. In looking back at her conversion, she might say something like this: “I know that I was young and impressionable, but the way in which the book (or film) made me feel about its characters moved me to further reflect upon animals and the animal industry, and I now realize that it was right to do so.” On her own view, at least, her spectatorship motivated and warranted her taking the further steps that ultimately led to her conversion. If she is right, then fictional narratives can possess—to at least some degree—what Raimond Gaita refers to as an ethical “authority.”
- Full Text:
- Date Issued: 2011
Evaluating The Potential Contribution Of Episodic Toxicity Data To Environmental Water Quality Management In South Africa
- Gordon, Andrew K, Mantel, Sukhmani K M, Muller, Nikite W J
- Authors: Gordon, Andrew K , Mantel, Sukhmani K M , Muller, Nikite W J
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438310 , vital:73450 , ISBN 978-1-4312-0070-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV259-10.pdf
- Description: An important aspect of the dynamics of nutrients and pollutants in natural systems is captured in the concept of allochthony, founded on the observation that nutrients and energy in a variety of forms are transferred between adjacent habitats, com-munities and ecosystems that are not routinely considered as connected. Different forms of nutrients and energy move across the conceptual boundaries of habitats via organisms’ activities or physical processes such as wind or water currents, and these transfers can represent important food subsidies. Such cross-partition ecolog-ical subsidies can augment the nutritional condition, biomass and biodiversity of communities, particularly where local production (or autochthony) alone may be inadequate to support local food webs. Furthermore, organic subsidies can influ-ence population dynamics, community interactions and ecosystem processes, and can represent dominant flux inputs in ecosystem budgets. Our intention was to explore organic nutrient fluxes in relation to a primarily lotic (i.e. flowing) aquatic sys-tem at the scale of a hydrological catchment.
- Full Text:
- Date Issued: 2011
- Authors: Gordon, Andrew K , Mantel, Sukhmani K M , Muller, Nikite W J
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438310 , vital:73450 , ISBN 978-1-4312-0070-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV259-10.pdf
- Description: An important aspect of the dynamics of nutrients and pollutants in natural systems is captured in the concept of allochthony, founded on the observation that nutrients and energy in a variety of forms are transferred between adjacent habitats, com-munities and ecosystems that are not routinely considered as connected. Different forms of nutrients and energy move across the conceptual boundaries of habitats via organisms’ activities or physical processes such as wind or water currents, and these transfers can represent important food subsidies. Such cross-partition ecolog-ical subsidies can augment the nutritional condition, biomass and biodiversity of communities, particularly where local production (or autochthony) alone may be inadequate to support local food webs. Furthermore, organic subsidies can influ-ence population dynamics, community interactions and ecosystem processes, and can represent dominant flux inputs in ecosystem budgets. Our intention was to explore organic nutrient fluxes in relation to a primarily lotic (i.e. flowing) aquatic sys-tem at the scale of a hydrological catchment.
- Full Text:
- Date Issued: 2011