Electrocatalytic studies of covalently immobilized metal tetra-amino phthalocyanines onto derivatized screen-printed gold electrodes
- Mashazi, Philani N, Nyokong, Tebello
- Authors: Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249059 , vital:51774 , xlink:href="https://doi.org/10.1007/s00604-010-0438-6"
- Description: Metal tetra-amino phthalocyanine complexes (MTAPc; where M is Co or Mn) were immobilized on screen-printed gold electrodes pre-modified with monolayers of benzylamino groups. The functionalized electrodes were then activated using benzene-1,4-dicarbaldehyde as a linker before MTAPc complexes were immobilized. The surface coverages for the modified electrodes confirmed the perpendicular orientation of the MTAPcs. The apparent electron transfer constant (kapp) for the electrodes is 2.2 × 10−5 cm.s−1 for both CoTAPc and MnTAPc modified electrodes as calculated with data from impedance measurements. The kapp values for the bare and benzylamino modified electrodes were found to be 1.2 × 10−4 cm.s−1 and 4.9 × 10−6 cm.s−1, respectively. The electrocatalysis of the modified electrodes towards detection of H2O2 gave significant peak current densities and electrocatalytic potentials at −0.28 V and −0.31 V for the MnTAPc and CoTAPc modified electrodes, respectively.
- Full Text:
- Date Issued: 2015
- Authors: Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249059 , vital:51774 , xlink:href="https://doi.org/10.1007/s00604-010-0438-6"
- Description: Metal tetra-amino phthalocyanine complexes (MTAPc; where M is Co or Mn) were immobilized on screen-printed gold electrodes pre-modified with monolayers of benzylamino groups. The functionalized electrodes were then activated using benzene-1,4-dicarbaldehyde as a linker before MTAPc complexes were immobilized. The surface coverages for the modified electrodes confirmed the perpendicular orientation of the MTAPcs. The apparent electron transfer constant (kapp) for the electrodes is 2.2 × 10−5 cm.s−1 for both CoTAPc and MnTAPc modified electrodes as calculated with data from impedance measurements. The kapp values for the bare and benzylamino modified electrodes were found to be 1.2 × 10−4 cm.s−1 and 4.9 × 10−6 cm.s−1, respectively. The electrocatalysis of the modified electrodes towards detection of H2O2 gave significant peak current densities and electrocatalytic potentials at −0.28 V and −0.31 V for the MnTAPc and CoTAPc modified electrodes, respectively.
- Full Text:
- Date Issued: 2015
'I won't be squeezed into someone else's frame': Stories of supervisor selection
- Harrison, Liz, McKenna, Sioux, Searle, Ruth
- Authors: Harrison, Liz , McKenna, Sioux , Searle, Ruth
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187395 , vital:44629 , xlink:href="https://hdl.handle.net/10520/EJC15100"
- Description: Using a collection of stories from a group of women who belong to a PhD support group, this article tracks the issue of choosing a supervisor. These women are all academics and therefore had some claim to an "insider" status but as novice researchers they were also "outsiders". Their discussions around how and why they chose their supervisors highlight issues often underplayed or ignored in textbooks on postgraduate supervision. In particular, this article examines issues of knowledge, embodied subjectivity and power by following three questions that arise from the data : whose knowing is important; who should I be, and whose PhD is it?
- Full Text:
- Date Issued: 2010
- Authors: Harrison, Liz , McKenna, Sioux , Searle, Ruth
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187395 , vital:44629 , xlink:href="https://hdl.handle.net/10520/EJC15100"
- Description: Using a collection of stories from a group of women who belong to a PhD support group, this article tracks the issue of choosing a supervisor. These women are all academics and therefore had some claim to an "insider" status but as novice researchers they were also "outsiders". Their discussions around how and why they chose their supervisors highlight issues often underplayed or ignored in textbooks on postgraduate supervision. In particular, this article examines issues of knowledge, embodied subjectivity and power by following three questions that arise from the data : whose knowing is important; who should I be, and whose PhD is it?
- Full Text:
- Date Issued: 2010
A watershed study on genetic diversity phylogenetic analysis of the Platypleura plumosa (Hemiptera Cicadidae) complex reveals catchment-specific lineages
- Price, Benjamin W, Barker, Nigel P, Villet, Martin H
- Authors: Price, Benjamin W , Barker, Nigel P , Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441711 , vital:73909 , https://doi.org/10.1016/j.ympev.2009.10.011
- Description: Historical biogeography studies have at their disposal a small suite of vicariance models to explain genetic differentiation within and between species. One of these processes involves the role of river catchments and their associated watersheds, in driving diversification and is applicable to both aquatic and terrestrial organisms. Although the idea of catchments structuring the genetic history of aquatic organisms is reasonably well understood, their effect on terrestrial organisms has largely been overlooked, with relevant studies being limited in scope. South Africa presents a perfect test-bed for elucidating this mechanism of diversification due to its rich biodiversity, range of climatic environments and many large river catchments. Here we use the cicadas of the Platypleura plumosa complex to highlight the importance of catchments and their associated watersheds in driving diversification of terrestrial invertebrates that lack an aquatic life-stage. Population structure was found to correspond to primary and in some cases secondary catchments; highlighting the need to include information on catchment structure when formulating hypotheses of population diversification. Recognizing that climate change in the near future is likely to alter the environment, and particularly precipitation patterns, insight into recent patterns of population change related to catchments may be useful in a conservation context.
- Full Text:
- Date Issued: 2010
- Authors: Price, Benjamin W , Barker, Nigel P , Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441711 , vital:73909 , https://doi.org/10.1016/j.ympev.2009.10.011
- Description: Historical biogeography studies have at their disposal a small suite of vicariance models to explain genetic differentiation within and between species. One of these processes involves the role of river catchments and their associated watersheds, in driving diversification and is applicable to both aquatic and terrestrial organisms. Although the idea of catchments structuring the genetic history of aquatic organisms is reasonably well understood, their effect on terrestrial organisms has largely been overlooked, with relevant studies being limited in scope. South Africa presents a perfect test-bed for elucidating this mechanism of diversification due to its rich biodiversity, range of climatic environments and many large river catchments. Here we use the cicadas of the Platypleura plumosa complex to highlight the importance of catchments and their associated watersheds in driving diversification of terrestrial invertebrates that lack an aquatic life-stage. Population structure was found to correspond to primary and in some cases secondary catchments; highlighting the need to include information on catchment structure when formulating hypotheses of population diversification. Recognizing that climate change in the near future is likely to alter the environment, and particularly precipitation patterns, insight into recent patterns of population change related to catchments may be useful in a conservation context.
- Full Text:
- Date Issued: 2010
Adult African sharptooth catfish, Clarias gariepinus, population dynamics in a small invaded warm-temperate impoundment
- Booth, Anthony J, Traasg, Graham L, Weyl, Olaf L F
- Authors: Booth, Anthony J , Traasg, Graham L , Weyl, Olaf L F
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446759 , vital:74558 , https://www.tandfonline.com/doi/abs/10.1080/15627020.2010.11657279
- Description: African sharptooth catfish, Clarias gariepinus, is a successful aquatic invader as it has a eurytopic physiology, is highly fecund, grows quickly and has an omnivorous diet. Despite possible threats that include predation of and competition with indigenous species, habitat degradation, and the spread of diseases and parasites, there is a lack of knowledge regarding its ecology and population dynamics within invaded systems. This study presents a mark–recapture experiment to investigate its population structure, natural mortality rate, population size and density within a population inhabiting a small, 76 ha invaded water supply reservoir in the temperate Eastern Cape region, South Africa.
- Full Text:
- Date Issued: 2010
- Authors: Booth, Anthony J , Traasg, Graham L , Weyl, Olaf L F
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446759 , vital:74558 , https://www.tandfonline.com/doi/abs/10.1080/15627020.2010.11657279
- Description: African sharptooth catfish, Clarias gariepinus, is a successful aquatic invader as it has a eurytopic physiology, is highly fecund, grows quickly and has an omnivorous diet. Despite possible threats that include predation of and competition with indigenous species, habitat degradation, and the spread of diseases and parasites, there is a lack of knowledge regarding its ecology and population dynamics within invaded systems. This study presents a mark–recapture experiment to investigate its population structure, natural mortality rate, population size and density within a population inhabiting a small, 76 ha invaded water supply reservoir in the temperate Eastern Cape region, South Africa.
- Full Text:
- Date Issued: 2010
An accidental but safe and effective use of Lucilia cuprina (Diptera: Calliphoridae) in maggot debridement therapy in Alexandria, Egypt
- Tantawi, Tarek I, Williams, Kirstin A, Villet, Martin H
- Authors: Tantawi, Tarek I , Williams, Kirstin A , Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442454 , vital:73986 , https://doi.org/10.1093/jmedent/47.3.491
- Description: The calliphorid fly, Lucilia cuprina (Wiedemann), is known to cause serious malign myiasis in animals, whereas its sibling species Lucilia sericata (Meigen) is commonly a carrion breeder and is used in maggot debridement therapy (MDT). The current study reports an accidental involvement of L. cuprina in MDT in Alexandria, Egypt, that has proved to be safe and effective. In November 2008, the laboratory colonies of L. sericata (the species regularly used in MDT) at the Faculty of Science, Alexandria University were renewed by Lucilia flies collected as third instar larvae on exposed rabbit carcasses. Flies from the new colonies were successfully used to heal the diabetic foot wounds of two patients at Alexandria Main University Hospital. Analysis of DNA sequences and adult and larval morphology then revealed that these flies were and still are L. cuprina. Breeding of this species in carrion in Alexandria is a new record. Despite the safety of this strain of L. cuprina in MDT, entomologists rearing blow flies for the purpose of wound debridement should regularly maintain high quality assurance of their species’ identity to avoid possible clinical complications that may result from the introduction of an unexpected and invasive species to their laboratory colonies.
- Full Text:
- Date Issued: 2010
- Authors: Tantawi, Tarek I , Williams, Kirstin A , Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442454 , vital:73986 , https://doi.org/10.1093/jmedent/47.3.491
- Description: The calliphorid fly, Lucilia cuprina (Wiedemann), is known to cause serious malign myiasis in animals, whereas its sibling species Lucilia sericata (Meigen) is commonly a carrion breeder and is used in maggot debridement therapy (MDT). The current study reports an accidental involvement of L. cuprina in MDT in Alexandria, Egypt, that has proved to be safe and effective. In November 2008, the laboratory colonies of L. sericata (the species regularly used in MDT) at the Faculty of Science, Alexandria University were renewed by Lucilia flies collected as third instar larvae on exposed rabbit carcasses. Flies from the new colonies were successfully used to heal the diabetic foot wounds of two patients at Alexandria Main University Hospital. Analysis of DNA sequences and adult and larval morphology then revealed that these flies were and still are L. cuprina. Breeding of this species in carrion in Alexandria is a new record. Despite the safety of this strain of L. cuprina in MDT, entomologists rearing blow flies for the purpose of wound debridement should regularly maintain high quality assurance of their species’ identity to avoid possible clinical complications that may result from the introduction of an unexpected and invasive species to their laboratory colonies.
- Full Text:
- Date Issued: 2010
Applications of polymerized metal tetra-amino phthalocyanines towards hydrogen peroxide detection
- Mashazi, Philani N, Togo, Chumunorwa, Limson, Janice L, Nyokong, Tebello
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice L , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
- Full Text:
- Date Issued: 2010
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice L , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
- Full Text:
- Date Issued: 2010
Art and Ethical Criticism, edited by Garry L. Hagberg
- Authors: Jones, Ward E
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275612 , vital:55063 , xlink:href="https://doi.org/10.1093/mind/fzq098"
- Description: Book Review: If there is a norm that a book’s title should give a reliable indication of its contents, Art and Ethical Criticism does not quite meet it. By my judgement, only seven of its twelve essays concern either the ethical criticism of art or the criticism of ethical positions within artworks.
- Full Text:
- Date Issued: 2010
- Authors: Jones, Ward E
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275612 , vital:55063 , xlink:href="https://doi.org/10.1093/mind/fzq098"
- Description: Book Review: If there is a norm that a book’s title should give a reliable indication of its contents, Art and Ethical Criticism does not quite meet it. By my judgement, only seven of its twelve essays concern either the ethical criticism of art or the criticism of ethical positions within artworks.
- Full Text:
- Date Issued: 2010
at the conference in munich
- Authors: Krueger, Anton
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229774 , vital:49709 , xlink:href="https://hdl.handle.net/10520/EJC47821"
- Full Text:
- Date Issued: 2010
- Authors: Krueger, Anton
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229774 , vital:49709 , xlink:href="https://hdl.handle.net/10520/EJC47821"
- Full Text:
- Date Issued: 2010
Biodiversity research and conservation: careers
- Authors: Rosenberg, Eureta
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391079 , vital:68615 , xlink:href="https://hdl.handle.net/10520/EJC89811"
- Description: It is the International Year of Biodiversity, and if you are interested in a career in biodiversity, there are many options from which to choose. This article introduces the dynamic and growing field of biodiversity management, research and conservation. It gives a taste of the varied careers that would suit different interests and talents and invites you to look with fresh eyes at the field and its possibilities.
- Full Text: false
- Date Issued: 2010
- Authors: Rosenberg, Eureta
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391079 , vital:68615 , xlink:href="https://hdl.handle.net/10520/EJC89811"
- Description: It is the International Year of Biodiversity, and if you are interested in a career in biodiversity, there are many options from which to choose. This article introduces the dynamic and growing field of biodiversity management, research and conservation. It gives a taste of the varied careers that would suit different interests and talents and invites you to look with fresh eyes at the field and its possibilities.
- Full Text: false
- Date Issued: 2010
Changing social imaginaries, multiplicities and ‘one sole world’: Reading Scandinavian environmental and sustainability education research papers with Badiou and Taylor at hand
- Authors: Lotz-Sisitka, Heila
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182506 , vital:43836 , xlink:href="https://doi.org/10.1080/13504620903504081"
- Description: Badiou’s ontological work draws attention to multiplicities – the oneness of ontology, which he explains can only become ontologically differentiated into events or sites through political, artistic or amorous practices that philosophies can think and invent from. He also draws attention to the fusion of events and sites, and he explains that events (such as producing special issues of journals located in particular sites) are reflexive. He also tells us, however, that the reflexive structure of an artistic or scientific event (such as producing a special issue of a journal) is not always immediately evident. In writing this response article I work with this concept – and probe how the production of events (such as a special issue of a journal produced in a specific site) may be reflexive. This is the purpose of the article. This response article therefore probes some of the political, structural and intellectual processes that come to shape scholarship in different sites, and here I draw on the insights into social imaginaries provided by Charles Taylor to develop a perspective on the scholarship that is reflected in this journal. Through this, I seek to open the notion of multiplicities, oneness and the particularities of our social imaginaries as themes for thinking about educational scholarship events produced within and across geo‐physical, socio‐ecological and socio‐economic spaces in different parts of the world.
- Full Text:
- Date Issued: 2010
- Authors: Lotz-Sisitka, Heila
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182506 , vital:43836 , xlink:href="https://doi.org/10.1080/13504620903504081"
- Description: Badiou’s ontological work draws attention to multiplicities – the oneness of ontology, which he explains can only become ontologically differentiated into events or sites through political, artistic or amorous practices that philosophies can think and invent from. He also draws attention to the fusion of events and sites, and he explains that events (such as producing special issues of journals located in particular sites) are reflexive. He also tells us, however, that the reflexive structure of an artistic or scientific event (such as producing a special issue of a journal) is not always immediately evident. In writing this response article I work with this concept – and probe how the production of events (such as a special issue of a journal produced in a specific site) may be reflexive. This is the purpose of the article. This response article therefore probes some of the political, structural and intellectual processes that come to shape scholarship in different sites, and here I draw on the insights into social imaginaries provided by Charles Taylor to develop a perspective on the scholarship that is reflected in this journal. Through this, I seek to open the notion of multiplicities, oneness and the particularities of our social imaginaries as themes for thinking about educational scholarship events produced within and across geo‐physical, socio‐ecological and socio‐economic spaces in different parts of the world.
- Full Text:
- Date Issued: 2010
Climate injustice: How should education respond?
- Authors: Lotz-Sisitka, Heila
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437268 , vital:73364 , ISBN 9780203866399 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203866399-11/climate-injustice-education-respond-heila-lotz-sisitka
- Description: The Fourth Assessment Report of the Intergovernmental Panel on Cli-mate Change (IPCC 2007) identifi es Africa as one of the continents of the world most vulnerable to climate change. Africa’s vulnerability to climate change is aggravated by the interaction of multiple stresses such as poverty, poor governance, and weak institutions, limited access to capi-tal (including technology), ecosystem degradation, confl ict and disasters (UNEP 2006), and a generally poor quality of education (UNESCO 2004). The climate injustices and exacerbating circumstances experienced by poor and weak states today lie in the long-term historical emergence of a modern (and increasingly global) world order framed by a hegemonic Westphalian state system. This state system privileges exclusive, undi-vided sovereignty over a bounded territory (Fraser 2008), and is known more popularly as the ‘nation state’ system.
- Full Text:
- Date Issued: 2010
- Authors: Lotz-Sisitka, Heila
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437268 , vital:73364 , ISBN 9780203866399 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203866399-11/climate-injustice-education-respond-heila-lotz-sisitka
- Description: The Fourth Assessment Report of the Intergovernmental Panel on Cli-mate Change (IPCC 2007) identifi es Africa as one of the continents of the world most vulnerable to climate change. Africa’s vulnerability to climate change is aggravated by the interaction of multiple stresses such as poverty, poor governance, and weak institutions, limited access to capi-tal (including technology), ecosystem degradation, confl ict and disasters (UNEP 2006), and a generally poor quality of education (UNESCO 2004). The climate injustices and exacerbating circumstances experienced by poor and weak states today lie in the long-term historical emergence of a modern (and increasingly global) world order framed by a hegemonic Westphalian state system. This state system privileges exclusive, undi-vided sovereignty over a bounded territory (Fraser 2008), and is known more popularly as the ‘nation state’ system.
- Full Text:
- Date Issued: 2010
Contemporary precision, bias and accuracy of minimum post-mortem intervals estimated using development of carrion-feeding insects
- Villet, Martin H, Richards, Cameron S, Midgley, John M
- Authors: Villet, Martin H , Richards, Cameron S , Midgley, John M
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442769 , vital:74032 , ISBN 978-1-4020-9684-6 , https://doi.org/10.1007/978-1-4020-9684-6_7
- Description: Medicocriminal forensic entomology focuses primarily on providing evidence of the amount of time that a corpse or carcass has been exposed to colonization by insects, which helps to estimate the post mortem interval (PMI). Specifically, the estimate is of a minimum post mortem interval (PMImin), because death may occur a variable amount of time before colonization (Fig. 7.1); the maximum post mortem interval (PMImax) is estimated using the time that the person was last seen alive. Forensic entomology derives the bulk of its evidence from two sources: the ecological succession of carrion insect communities and the development of immature insects (Byrd and Castner 2001; Catts and Haskel 1990; Smith 1986). This chapter is concerned with assessing the confidence that can be placed in the accuracy of estimates derived from insect development. (Schoenly et al. 1996) dealt with this theme in succession-based estimates of PMImin.
- Full Text:
- Date Issued: 2010
- Authors: Villet, Martin H , Richards, Cameron S , Midgley, John M
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442769 , vital:74032 , ISBN 978-1-4020-9684-6 , https://doi.org/10.1007/978-1-4020-9684-6_7
- Description: Medicocriminal forensic entomology focuses primarily on providing evidence of the amount of time that a corpse or carcass has been exposed to colonization by insects, which helps to estimate the post mortem interval (PMI). Specifically, the estimate is of a minimum post mortem interval (PMImin), because death may occur a variable amount of time before colonization (Fig. 7.1); the maximum post mortem interval (PMImax) is estimated using the time that the person was last seen alive. Forensic entomology derives the bulk of its evidence from two sources: the ecological succession of carrion insect communities and the development of immature insects (Byrd and Castner 2001; Catts and Haskel 1990; Smith 1986). This chapter is concerned with assessing the confidence that can be placed in the accuracy of estimates derived from insect development. (Schoenly et al. 1996) dealt with this theme in succession-based estimates of PMImin.
- Full Text:
- Date Issued: 2010
Data classification for artificial intelligence construct training to aid in network incident identification using network telescope data
- Cowie, Bradley, Irwin, Barry V W
- Authors: Cowie, Bradley , Irwin, Barry V W
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430125 , vital:72667 , https://doi.org/10.1145/1899503.1899544
- Description: This paper considers the complexities involved in obtaining training da-ta for use by artificial intelligence constructs to identify potential network incidents using passive network telescope data. While a large amount of data obtained from network telescopes exists, this data is not current-ly marked for known incidents. Problems related to this marking process include the accuracy of the markings, the validity of the original data and the time involved. In an attempt to solve these issues two methods of training data generation are considered namely; manual identification and automated generation. The manual technique considers heuristics for finding network incidents while the automated technique considers building simulated data sets using existing models of virus propagation and malicious activity. An example artificial intelligence system is then constructed using these marked datasets.
- Full Text:
- Date Issued: 2010
- Authors: Cowie, Bradley , Irwin, Barry V W
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430125 , vital:72667 , https://doi.org/10.1145/1899503.1899544
- Description: This paper considers the complexities involved in obtaining training da-ta for use by artificial intelligence constructs to identify potential network incidents using passive network telescope data. While a large amount of data obtained from network telescopes exists, this data is not current-ly marked for known incidents. Problems related to this marking process include the accuracy of the markings, the validity of the original data and the time involved. In an attempt to solve these issues two methods of training data generation are considered namely; manual identification and automated generation. The manual technique considers heuristics for finding network incidents while the automated technique considers building simulated data sets using existing models of virus propagation and malicious activity. An example artificial intelligence system is then constructed using these marked datasets.
- Full Text:
- Date Issued: 2010
Development of an IMS Compliant, Cross Platform Client Using the JAIN SIP Applet Phone
- Muswera, Walter T, Terzoli, Alfredo
- Authors: Muswera, Walter T , Terzoli, Alfredo
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431274 , vital:72760 , https://www.cs.ru.ac.za/research/g09M3278/Muswera.pdf
- Description: Several open source SIP/IMS Clients are currently in use in the Rhodes University Convergence Research Group. However, there is no single Client that provides researchers with all the required functionality need-ed to test the applications they have developed. Integrating advanced features into a single Client can help to speed up testing as well as pro-vide a variety of innovative communication services. In this paper we present an overview of two popular SIP/IMS Clients currently in use. We also discuss the features and design architecture of a Client called JAIN SIP Applet Phone (JSAP) which will be used as a basis for the development of a new IMS compliant Client. We then analyse what functionality JSAP lacks and propose features that need to be imple-mented.
- Full Text:
- Date Issued: 2010
- Authors: Muswera, Walter T , Terzoli, Alfredo
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431274 , vital:72760 , https://www.cs.ru.ac.za/research/g09M3278/Muswera.pdf
- Description: Several open source SIP/IMS Clients are currently in use in the Rhodes University Convergence Research Group. However, there is no single Client that provides researchers with all the required functionality need-ed to test the applications they have developed. Integrating advanced features into a single Client can help to speed up testing as well as pro-vide a variety of innovative communication services. In this paper we present an overview of two popular SIP/IMS Clients currently in use. We also discuss the features and design architecture of a Client called JAIN SIP Applet Phone (JSAP) which will be used as a basis for the development of a new IMS compliant Client. We then analyse what functionality JSAP lacks and propose features that need to be imple-mented.
- Full Text:
- Date Issued: 2010
Ecological impacts of small dams on South African rivers Part 1: Drivers of change–water quantity and quality
- Mantel, Sukhmani K, Hughes, Denis A, Muller, Nikite W J
- Authors: Mantel, Sukhmani K , Hughes, Denis A , Muller, Nikite W J
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438099 , vital:73435 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2398.pdf
- Description: Impacts of large dams are well-known and quantifiable, while small dams have generally been perceived as benign, both socially and envi-ronmentally. The present study quantifies the cumulative impacts of small dams on the water quality (physico-chemistry and invertebrate biotic indices) and quantity (discharge) of downstream rivers in 2 South African regions. The information from 2 South African national data-bases was used for evaluating the cumulative impacts on water quality and quantity. Physico-chemistry and biological data were obtained from the River Health Programme, and discharge data at stream flow gauges was obtained from the Hydrological Information System. Multivariate analyses were conducted to establish broad patterns for cumulative impacts of small dams across the 2 regions–Western Cape (winter rain-fall, temperate, south-western coast) and Mpumalanga (summer rain-fall, tropical, eastern coast). Multivariate analyses found that the chang-es in macroinvertebrate indices and the stream’s physico-chemistry were more strongly correlated with the density of small dams in the catchment (as a measure of cumulative impact potential) relative to the storage capacity of large dams. T-tests on the data, not including sam-ples with upstream large dams, indicated that the high density of small dams significantly reduced low flows and increased certain physico-chemistry variables (particularly total dissolved salts) in both the re-gions, along with associated significant reductions in a macroinverte-brate index (SASS4 average score per taxon). Regional differences were apparent in the results for discharge reductions and the macroin-vertebrate index. The results suggest that the cumulative effect of a high number of small dams is impacting the quality and quantity of wa-ters in South African rivers and that these impacts need to be systemat-ically incorporated into the monitoring protocol of the environmental wa-ter requirements.
- Full Text:
- Date Issued: 2010
- Authors: Mantel, Sukhmani K , Hughes, Denis A , Muller, Nikite W J
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438099 , vital:73435 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2398.pdf
- Description: Impacts of large dams are well-known and quantifiable, while small dams have generally been perceived as benign, both socially and envi-ronmentally. The present study quantifies the cumulative impacts of small dams on the water quality (physico-chemistry and invertebrate biotic indices) and quantity (discharge) of downstream rivers in 2 South African regions. The information from 2 South African national data-bases was used for evaluating the cumulative impacts on water quality and quantity. Physico-chemistry and biological data were obtained from the River Health Programme, and discharge data at stream flow gauges was obtained from the Hydrological Information System. Multivariate analyses were conducted to establish broad patterns for cumulative impacts of small dams across the 2 regions–Western Cape (winter rain-fall, temperate, south-western coast) and Mpumalanga (summer rain-fall, tropical, eastern coast). Multivariate analyses found that the chang-es in macroinvertebrate indices and the stream’s physico-chemistry were more strongly correlated with the density of small dams in the catchment (as a measure of cumulative impact potential) relative to the storage capacity of large dams. T-tests on the data, not including sam-ples with upstream large dams, indicated that the high density of small dams significantly reduced low flows and increased certain physico-chemistry variables (particularly total dissolved salts) in both the re-gions, along with associated significant reductions in a macroinverte-brate index (SASS4 average score per taxon). Regional differences were apparent in the results for discharge reductions and the macroin-vertebrate index. The results suggest that the cumulative effect of a high number of small dams is impacting the quality and quantity of wa-ters in South African rivers and that these impacts need to be systemat-ically incorporated into the monitoring protocol of the environmental wa-ter requirements.
- Full Text:
- Date Issued: 2010
Ecological impacts of small dams on South African rivers Part 2: Biotic response–abundance and composition of macroinvertebrate communities
- Mantel, Sukhmani K, Muller, Nikite W J, Hughes, Denis A
- Authors: Mantel, Sukhmani K , Muller, Nikite W J , Hughes, Denis A
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438087 , vital:73434 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2354.pdf
- Description: This paper investigates the cumulative impacts of small dams on inver-tebrate communities in 2 regions of South Africa–the Western Cape and Mpumalanga. Previous research found reduced discharge, in-creased total dissolved salts, and a decrease in average score per tax-on (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigat-ed using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catch-ment in foothill-gravel streams (in both Western Cape and Mpuma-langa) and in foothill-cobble streams (in Western Cape only). Opportun-istic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and sea-sons) and detailed (at species level) collection of data to verify the re-sults of cumulative effects of small dams. This can further the devel-opment of a framework for small-dam construction and management that will limit their impact on river catchments.
- Full Text:
- Date Issued: 2010
- Authors: Mantel, Sukhmani K , Muller, Nikite W J , Hughes, Denis A
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438087 , vital:73434 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2354.pdf
- Description: This paper investigates the cumulative impacts of small dams on inver-tebrate communities in 2 regions of South Africa–the Western Cape and Mpumalanga. Previous research found reduced discharge, in-creased total dissolved salts, and a decrease in average score per tax-on (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigat-ed using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catch-ment in foothill-gravel streams (in both Western Cape and Mpuma-langa) and in foothill-cobble streams (in Western Cape only). Opportun-istic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and sea-sons) and detailed (at species level) collection of data to verify the re-sults of cumulative effects of small dams. This can further the devel-opment of a framework for small-dam construction and management that will limit their impact on river catchments.
- Full Text:
- Date Issued: 2010
Electrocatalytic oxidation of amitrole and diuron on iron (II) tetraaminophthalocyanine-single walled carbon nanotube dendrimer
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262611 , vital:53536 , xlink:href="https://doi.org/10.1016/j.electacta.2009.12.051"
- Description: FeTAPc-single walled carbon nanotube (SWCNT) dendrimers are employed as glassy carbon electrode modifiers for the electrocatalytic oxidations of amitrole and diuron. The catalytic rate constants were 4.55 × 103 M−1 s−1 and 1.79 × 104 M−1 s−1 for amitrole and diuron, respectively using chronoamperometric studies. The diffusion constants were found to be 1.52 × 10−4 cm2 s−1 and 1.91 × 10−4 cm2 s−1 for diuron and amitrole, respectively. The linear concentration range for both were from 5.0 × 10−5 to 1.0 × 10−4 M and sensitivities of 0.6603 μA/μM and 0.6641 μA/μM for amitrole and diuron, with corresponding limits of detection of 2.15 × 10−7 and 2.6 × 10−7 M using the 3δ notation, respectively.
- Full Text:
- Date Issued: 2010
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262611 , vital:53536 , xlink:href="https://doi.org/10.1016/j.electacta.2009.12.051"
- Description: FeTAPc-single walled carbon nanotube (SWCNT) dendrimers are employed as glassy carbon electrode modifiers for the electrocatalytic oxidations of amitrole and diuron. The catalytic rate constants were 4.55 × 103 M−1 s−1 and 1.79 × 104 M−1 s−1 for amitrole and diuron, respectively using chronoamperometric studies. The diffusion constants were found to be 1.52 × 10−4 cm2 s−1 and 1.91 × 10−4 cm2 s−1 for diuron and amitrole, respectively. The linear concentration range for both were from 5.0 × 10−5 to 1.0 × 10−4 M and sensitivities of 0.6603 μA/μM and 0.6641 μA/μM for amitrole and diuron, with corresponding limits of detection of 2.15 × 10−7 and 2.6 × 10−7 M using the 3δ notation, respectively.
- Full Text:
- Date Issued: 2010
Electrochemical, spectroscopic and microscopic studies of new manganese phthalocyanine complexes in solution and as self-assembled monolayers on gold
- Coates, Megan, Antunes, Edith M, Nyokong, Tebello
- Authors: Coates, Megan , Antunes, Edith M , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261144 , vital:53363 , xlink:href="https://doi.org/10.1142/S1088424610002471"
- Description: Four new manganese(III) phthalocyanines (3a–d), octasubstituted at the peripheral position with pentylthio, decylthio, benzylthio, and phenylthio groups, respectively, were synthesized. Their specific electrochemical, spectroscopic and microscopic properties in solution and as self-assembled monolayers on gold were characterized. The UV-vis spectra confirmed red-shifted Q bands for all the complexes, due to the effect of the central metal and the electron-donating substituents. Three redox couples were visible during cyclic voltammetry studies for the four complexes, and spectroelectrochemistry confirmed the couples as corresponding to MnIIIPc-2/MnIIPc-2 (II) (metal reduction), MnIIPc-2/MnIIPc-3 (III) (ring reduction) and MnIIIPc-1/MnIIIPc-2 (I) (ring oxidation). Electrochemistry was also used to determine the blocking characteristics of the MnPc self-assembled monolayers on gold, which proved to be highly dependent on the type of substituent. Other methods of characterization included Raman spectroscopy, atomic force and scanning electrochemical microscopy analyses of the SAMs.
- Full Text:
- Date Issued: 2010
- Authors: Coates, Megan , Antunes, Edith M , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261144 , vital:53363 , xlink:href="https://doi.org/10.1142/S1088424610002471"
- Description: Four new manganese(III) phthalocyanines (3a–d), octasubstituted at the peripheral position with pentylthio, decylthio, benzylthio, and phenylthio groups, respectively, were synthesized. Their specific electrochemical, spectroscopic and microscopic properties in solution and as self-assembled monolayers on gold were characterized. The UV-vis spectra confirmed red-shifted Q bands for all the complexes, due to the effect of the central metal and the electron-donating substituents. Three redox couples were visible during cyclic voltammetry studies for the four complexes, and spectroelectrochemistry confirmed the couples as corresponding to MnIIIPc-2/MnIIPc-2 (II) (metal reduction), MnIIPc-2/MnIIPc-3 (III) (ring reduction) and MnIIIPc-1/MnIIIPc-2 (I) (ring oxidation). Electrochemistry was also used to determine the blocking characteristics of the MnPc self-assembled monolayers on gold, which proved to be highly dependent on the type of substituent. Other methods of characterization included Raman spectroscopy, atomic force and scanning electrochemical microscopy analyses of the SAMs.
- Full Text:
- Date Issued: 2010
Ethics-oriented learning in environmental education workplaces: An activity theory approach
- Authors: Olvitt, Lausanne L
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370961 , vital:66398 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122874"
- Description: In the context of increasing national and global environmental challenges and their implications for the working world, new ethics and practices are being introduced into workplaces that take better account of socio-ecological relations. Little is understood, however, about the nature of ethics-oriented workplace learning. Drawing on Cultural Historical Activity Theory (CHAT), which enables historically and contextually situated relational perspectives to emerge, this paper explores contradictions in the activity systems of two young environmental education learner-practitioners struggling to engage with the ethical dimensions of their professional work and the professional development course they are studying. The study focuses in particular on the environmental values and ethics component of their course – a year-long Learnership in Environmental Education, Training and Development Practices (EETDP). The paper reflects how tensions and contradictions within and between the interacting activity systems of the workplace, the course, and its regulating qualifications authority influence the teaching and learning of the environmental ethics component of the course. Ethics-oriented teaching and learning processes are found to be strongly influenced by the ‘rules’ and ‘mediating tools’ of these interacting systems, but these are often at odds with the ethical perspectives, socio-cultural context and skills of the ‘subject’ and ‘community’. These systemic contradictions can be more fully understood when their cultural and historical origins are made explicit. The analytical process has led to a more nuanced understanding of ethics-oriented teaching and learning in a workplace-based course, and has revealed several areas needing more careful research (particularly the area of environmental discourses) and the explicit and implicit language of ethics.
- Full Text:
- Date Issued: 2010
- Authors: Olvitt, Lausanne L
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370961 , vital:66398 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122874"
- Description: In the context of increasing national and global environmental challenges and their implications for the working world, new ethics and practices are being introduced into workplaces that take better account of socio-ecological relations. Little is understood, however, about the nature of ethics-oriented workplace learning. Drawing on Cultural Historical Activity Theory (CHAT), which enables historically and contextually situated relational perspectives to emerge, this paper explores contradictions in the activity systems of two young environmental education learner-practitioners struggling to engage with the ethical dimensions of their professional work and the professional development course they are studying. The study focuses in particular on the environmental values and ethics component of their course – a year-long Learnership in Environmental Education, Training and Development Practices (EETDP). The paper reflects how tensions and contradictions within and between the interacting activity systems of the workplace, the course, and its regulating qualifications authority influence the teaching and learning of the environmental ethics component of the course. Ethics-oriented teaching and learning processes are found to be strongly influenced by the ‘rules’ and ‘mediating tools’ of these interacting systems, but these are often at odds with the ethical perspectives, socio-cultural context and skills of the ‘subject’ and ‘community’. These systemic contradictions can be more fully understood when their cultural and historical origins are made explicit. The analytical process has led to a more nuanced understanding of ethics-oriented teaching and learning in a workplace-based course, and has revealed several areas needing more careful research (particularly the area of environmental discourses) and the explicit and implicit language of ethics.
- Full Text:
- Date Issued: 2010
Extending Java’s communication mechanisms for multicore processors
- Authors: Wells, George C
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430526 , vital:72697 , https://citeseerx.ist.psu.edu/document?repid=rep1type=pdfdoi=4068ed60c317e81dc70288cf36ff586dc057233f
- Description: With the current trend towards the increased use of multicore proces-sors, there is a growing need for simple, efficient parallel programming mechanisms. While Java has good support for multithreaded and dis-tributed application development, our research into tuple-space systems for multicore processors highlighted a gap in the concurrency facilities available in Java. This arises in the context of independent applications (running in separate virtual machines) that need to synchronise their ac-tivities or communicate with each other. There are several possible solu-tions to this problem, ranging from extensions to the language and/or runtime environment through to the use of distributed programming methods. Using the latter introduces considerable performance over-heads, and so we explored the use of the Java Native Interface in order to take advantage of the interprocess communication (IPC) facilities pro-vided by the underlying operating system. The analysis and comparison of the performance of the standard approaches and our prototype library suggest that there are real benefits to be gained by alternative ap-proaches to the provision of IPC mechanisms for independent Java programs executing on multicore systems. We hope that these findings will spur further investigation of this problem and other possible solu-tions.
- Full Text:
- Date Issued: 2010
- Authors: Wells, George C
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430526 , vital:72697 , https://citeseerx.ist.psu.edu/document?repid=rep1type=pdfdoi=4068ed60c317e81dc70288cf36ff586dc057233f
- Description: With the current trend towards the increased use of multicore proces-sors, there is a growing need for simple, efficient parallel programming mechanisms. While Java has good support for multithreaded and dis-tributed application development, our research into tuple-space systems for multicore processors highlighted a gap in the concurrency facilities available in Java. This arises in the context of independent applications (running in separate virtual machines) that need to synchronise their ac-tivities or communicate with each other. There are several possible solu-tions to this problem, ranging from extensions to the language and/or runtime environment through to the use of distributed programming methods. Using the latter introduces considerable performance over-heads, and so we explored the use of the Java Native Interface in order to take advantage of the interprocess communication (IPC) facilities pro-vided by the underlying operating system. The analysis and comparison of the performance of the standard approaches and our prototype library suggest that there are real benefits to be gained by alternative ap-proaches to the provision of IPC mechanisms for independent Java programs executing on multicore systems. We hope that these findings will spur further investigation of this problem and other possible solu-tions.
- Full Text:
- Date Issued: 2010