The final instar exuvium of Pycna semiclara Germar, 1834 (Hemiptera Cicadidae)
- Midgley, John M, Bouwer, Nicolette, Villet, Martin H
- Authors: Midgley, John M , Bouwer, Nicolette , Villet, Martin H
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440695 , vital:73804 , https://hdl.handle.net/10520/EJC136752
- Description: Exuviae of the cicada Pycna semiclara were found next to freshly eclosed adults. The exuvium of Pycna Semiclara is described and illustrated for the first time and a key is presented to distinguish the exuvium of this species from those of Platypleura stridula and Platypleura capensis, the only other species of cicadas from southern Africa for which exuviae have been described.
- Full Text:
- Date Issued: 2013
- Authors: Midgley, John M , Bouwer, Nicolette , Villet, Martin H
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440695 , vital:73804 , https://hdl.handle.net/10520/EJC136752
- Description: Exuviae of the cicada Pycna semiclara were found next to freshly eclosed adults. The exuvium of Pycna Semiclara is described and illustrated for the first time and a key is presented to distinguish the exuvium of this species from those of Platypleura stridula and Platypleura capensis, the only other species of cicadas from southern Africa for which exuviae have been described.
- Full Text:
- Date Issued: 2013
The Formation of 2, 2, 4-Trimethyl-2, 3-dihydro-1 H-1, 5-Benzodiazepine from 1, 2-Diaminobenzene in the Presence of Acetone
- Odame, Felix, Kleyi, Phumelele, Hosten, Eric C, Betz, Richard, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Kleyi, Phumelele , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448952 , vital:74773 , xlink:href="https://doi.org/10.3390/molecules181114293"
- Description: In an attempt to synthesize a 2-substituted benzimidazole from the reaction of o-phenylenediamine and isophthalic acid in the presence of acetone and ethanol under microwave irradiation, a salt of the isophthalate ion and 2,2,4-trimethyl-2,3-dihydro-1H-1,5-benzodiazepin-5-ium ion was obtained. The condensation of two moles of acetone with the amine groups resulted in the formation of the benzodiazepine which crystallized as an iminium cation forming a salt with the isophthalate anion. The formation of benzodiazepine was also confirmed by performing the reaction of o-phenylenediamine with excess acetone in ethanol under conventional heating conditions. The compounds were characterized by NMR, FTIR, HRMS and microanalysis as well as X-ray crystallography. The reaction mechanism leading to the formation of benzodiazepine is also discussed.
- Full Text:
- Date Issued: 2013
- Authors: Odame, Felix , Kleyi, Phumelele , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448952 , vital:74773 , xlink:href="https://doi.org/10.3390/molecules181114293"
- Description: In an attempt to synthesize a 2-substituted benzimidazole from the reaction of o-phenylenediamine and isophthalic acid in the presence of acetone and ethanol under microwave irradiation, a salt of the isophthalate ion and 2,2,4-trimethyl-2,3-dihydro-1H-1,5-benzodiazepin-5-ium ion was obtained. The condensation of two moles of acetone with the amine groups resulted in the formation of the benzodiazepine which crystallized as an iminium cation forming a salt with the isophthalate anion. The formation of benzodiazepine was also confirmed by performing the reaction of o-phenylenediamine with excess acetone in ethanol under conventional heating conditions. The compounds were characterized by NMR, FTIR, HRMS and microanalysis as well as X-ray crystallography. The reaction mechanism leading to the formation of benzodiazepine is also discussed.
- Full Text:
- Date Issued: 2013
The gold of one’s ring is not far more precious than the gold of one’s heart: Reported life satisfaction among married and cohabitating South African adults
- Botha, Ferdi, Booysen, Frikkie
- Authors: Botha, Ferdi , Booysen, Frikkie
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396181 , vital:69156 , xlink:href=" https://doi.org/10.1007/s10902-012-9337-3"
- Description: This paper tests for differences in reported life satisfaction between married and cohabiting persons, i.e. the cohabitation gap, and in particular whether selection factors can explain the cohabitation gap. The paper also explores whether age at marriage and at start of cohabitation as well as the duration of relationship type matters for subjective well-being. Based on statistical and regression analysis of the 2008 National Income Dynamics Survey, married and cohabiting persons exhibit some differences in their respective determinants of life satisfaction. While the age at relationship commencement has no relationship with well-being, there is evidence to suggest that married people become more satisfied at a later stage in marriage, while cohabitants are more satisfied initially. A significant cohabitation gap exists (0.251), but after controlling for various selection factors, the cohabitation gap virtually disappears (0.042) and becomes insignificant, which suggests that marriage and cohabitation are very similar in South Africa. Relative income, absolute income, and education explain the largest part of the cohabitation gap. Against the global backdrop of an increasing trend towards cohabitation and declining marriage rates, the overall results of this paper suggest that, since a cohabitation gap no longer exists after controlling for selection factors, South Africans may as well not go the “official route” of entering into marriage, as cohabitation provides similar benefits in terms of its contribution to individual satisfaction with life.
- Full Text:
- Date Issued: 2013
- Authors: Botha, Ferdi , Booysen, Frikkie
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396181 , vital:69156 , xlink:href=" https://doi.org/10.1007/s10902-012-9337-3"
- Description: This paper tests for differences in reported life satisfaction between married and cohabiting persons, i.e. the cohabitation gap, and in particular whether selection factors can explain the cohabitation gap. The paper also explores whether age at marriage and at start of cohabitation as well as the duration of relationship type matters for subjective well-being. Based on statistical and regression analysis of the 2008 National Income Dynamics Survey, married and cohabiting persons exhibit some differences in their respective determinants of life satisfaction. While the age at relationship commencement has no relationship with well-being, there is evidence to suggest that married people become more satisfied at a later stage in marriage, while cohabitants are more satisfied initially. A significant cohabitation gap exists (0.251), but after controlling for various selection factors, the cohabitation gap virtually disappears (0.042) and becomes insignificant, which suggests that marriage and cohabitation are very similar in South Africa. Relative income, absolute income, and education explain the largest part of the cohabitation gap. Against the global backdrop of an increasing trend towards cohabitation and declining marriage rates, the overall results of this paper suggest that, since a cohabitation gap no longer exists after controlling for selection factors, South Africans may as well not go the “official route” of entering into marriage, as cohabitation provides similar benefits in terms of its contribution to individual satisfaction with life.
- Full Text:
- Date Issued: 2013
The interaction of silver nanoparticles with low symmetry cysteinyl metallophthalocyanines and their antimicrobial effect
- Masilela, Nkosiphile, Nyokong, Tebello
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193735 , vital:45391 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.01.009"
- Description: This work reports on the synthesis of silver nanoparticles and their antimicrobial activity alone and in the presence of low symmetry phthalocyanines. The photochemical behaviour of various low symmetry phthalocyanines in the presence of AgNPs is investigated in DMF. A slight improvement in the photochemical behaviour and antimicrobial activity was achieved in the presence of AgNPs for all the complexes. The spherically shaped AgNPs gave the highest antimicrobial activity compared to the triangular and cubic structures. The (OH)2GeMCsPc complex gave the highest antimicrobial activity towards Staphylococcus aureas, both alone and in the presence of AgNPs under illumination with light.
- Full Text:
- Date Issued: 2013
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193735 , vital:45391 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.01.009"
- Description: This work reports on the synthesis of silver nanoparticles and their antimicrobial activity alone and in the presence of low symmetry phthalocyanines. The photochemical behaviour of various low symmetry phthalocyanines in the presence of AgNPs is investigated in DMF. A slight improvement in the photochemical behaviour and antimicrobial activity was achieved in the presence of AgNPs for all the complexes. The spherically shaped AgNPs gave the highest antimicrobial activity compared to the triangular and cubic structures. The (OH)2GeMCsPc complex gave the highest antimicrobial activity towards Staphylococcus aureas, both alone and in the presence of AgNPs under illumination with light.
- Full Text:
- Date Issued: 2013
The Monkey Cage
- Authors: Krueger, Anton
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229763 , vital:49708 , xlink:href="https://hdl.handle.net/10520/EJC149510"
- Full Text:
- Date Issued: 2013
- Authors: Krueger, Anton
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229763 , vital:49708 , xlink:href="https://hdl.handle.net/10520/EJC149510"
- Full Text:
- Date Issued: 2013
The Personal Is the International
- Authors: Magadla, Siphokazi
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298674 , vital:57726 , xlink:href="https://doi.org/10.1080/02589346.2013.856568"
- Description: The article reflects on why I opted for Political Science as my career. It tells of a society where once black women could only imagine themselves either as maids, teachers or nurses—this was my mother's world. The narrative shows how a racialised and gendered history shapes both my hopes for a particular kind of international relations theory and practice, as it shapes my frustrations and anxieties about my own future in the discipline. I also locate my place in the discipline within broader global ‘disruptions’ that see previously marginalised actors moving to the centre of international life. I also attempt to demonstrate that international relations today is located in globalised peace but within localised extremes of poverty and privilege. I make the case that the challenge to International Relations (IR) theory today is to find a language, a new language, in which to articulate the contradictions of a globalised peace that exists within localised extremes of poverty and privilege.
- Full Text:
- Date Issued: 2013
- Authors: Magadla, Siphokazi
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298674 , vital:57726 , xlink:href="https://doi.org/10.1080/02589346.2013.856568"
- Description: The article reflects on why I opted for Political Science as my career. It tells of a society where once black women could only imagine themselves either as maids, teachers or nurses—this was my mother's world. The narrative shows how a racialised and gendered history shapes both my hopes for a particular kind of international relations theory and practice, as it shapes my frustrations and anxieties about my own future in the discipline. I also locate my place in the discipline within broader global ‘disruptions’ that see previously marginalised actors moving to the centre of international life. I also attempt to demonstrate that international relations today is located in globalised peace but within localised extremes of poverty and privilege. I make the case that the challenge to International Relations (IR) theory today is to find a language, a new language, in which to articulate the contradictions of a globalised peace that exists within localised extremes of poverty and privilege.
- Full Text:
- Date Issued: 2013
The photophysical and photochemical behaviour of coumarin-derivatized zinc phthalocyanine when conjugated with gold nanoparticles and electrospun into polymer fibers
- Tombe, Sekai, Antunes, Edith M, Nyokong, Tebello
- Authors: Tombe, Sekai , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232534 , vital:50000 , xlink:href="https://doi.org/10.1039/C2NJ40984D"
- Description: Polymer composite fibers doped with phthalocyanines and phthalocyanine-functionalized gold nanoparticles were developed. The phthalocyanine and phthalocyanine-functionalized gold nanoparticles have been characterized using UV/Vis, fluorescence and X-ray photoelectron spectroscopy (XPS), time correlated single photon counting (TCSPC), time-resolved emission spectra (TRES) and transmission electron microscopy (TEM). The changes in photophysical and photochemical behavior of the phthalocyanines induced by their interaction with gold nanoparticles and polystyrene were also investigated. In the presence of gold nanoparticles, the fluorescence lifetimes and quantum yields of the phthalocyanine decreased, whereas the singlet oxygen quantum yield increased. This work shows that polymer composite fibers could be used as functional fibers for a variety of applications such as gas sensing when using the advantageous properties of phthalocyanines and gold nanoparticles.
- Full Text:
- Date Issued: 2013
- Authors: Tombe, Sekai , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232534 , vital:50000 , xlink:href="https://doi.org/10.1039/C2NJ40984D"
- Description: Polymer composite fibers doped with phthalocyanines and phthalocyanine-functionalized gold nanoparticles were developed. The phthalocyanine and phthalocyanine-functionalized gold nanoparticles have been characterized using UV/Vis, fluorescence and X-ray photoelectron spectroscopy (XPS), time correlated single photon counting (TCSPC), time-resolved emission spectra (TRES) and transmission electron microscopy (TEM). The changes in photophysical and photochemical behavior of the phthalocyanines induced by their interaction with gold nanoparticles and polystyrene were also investigated. In the presence of gold nanoparticles, the fluorescence lifetimes and quantum yields of the phthalocyanine decreased, whereas the singlet oxygen quantum yield increased. This work shows that polymer composite fibers could be used as functional fibers for a variety of applications such as gas sensing when using the advantageous properties of phthalocyanines and gold nanoparticles.
- Full Text:
- Date Issued: 2013
The relationship between marital status and life satisfaction among South African adults
- Botha, Ferdi, Booysen, Frikkie
- Authors: Botha, Ferdi , Booysen, Frikkie
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396207 , vital:69158 , xlink:href="https://hdl.handle.net/10520/EJC138900"
- Description: This article examines the association between marital status and reported life satisfaction in South Africa. Using the 2008 National Income Dynamics Survey, the relationship between marital status and life satisfaction is heterogeneous. In the overall sample, life satisfaction is significantly higher for married compared to widowed individuals, while the former are more satisfied than those from all other marital statuses. In the overall and female samples, married people are more satisfied compared to those from all other marital status groups. Married men are not significantly more satisfied than men from other marital statuses as a whole. Marriage is positively associated with life satisfaction among women, but not among men.
- Full Text:
- Date Issued: 2013
- Authors: Botha, Ferdi , Booysen, Frikkie
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396207 , vital:69158 , xlink:href="https://hdl.handle.net/10520/EJC138900"
- Description: This article examines the association between marital status and reported life satisfaction in South Africa. Using the 2008 National Income Dynamics Survey, the relationship between marital status and life satisfaction is heterogeneous. In the overall sample, life satisfaction is significantly higher for married compared to widowed individuals, while the former are more satisfied than those from all other marital statuses. In the overall and female samples, married people are more satisfied compared to those from all other marital status groups. Married men are not significantly more satisfied than men from other marital statuses as a whole. Marriage is positively associated with life satisfaction among women, but not among men.
- Full Text:
- Date Issued: 2013
The synthesis and characterisation of magnetic nanoparticles and their interaction with a zinc phthalocyanine
- Antunes, Edith M, Rapulenyane, Nomasonto, Ledwaba, Mpho, Litwinski, Christian, Chidawanyika, Wadzanai J U, Nyokong, Tebello
- Authors: Antunes, Edith M , Rapulenyane, Nomasonto , Ledwaba, Mpho , Litwinski, Christian , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242111 , vital:51002 , xlink:href="https://doi.org/10.1016/j.inoche.2012.12.010"
- Description: A variety of nanoparticles (NPs), including FePt nanoparticles with Fe as the shell (2) or Pt as the shell (3), Pt NPs (4), and FePd (5) were synthesised, characterised and their effect on a zinc phthalocyanine (1) tetra-substituted with a pyridyl-oxy substituent studied using UV/Vis and fluorescence spectroscopy (including time correlated single photon counting, TCSPC). The nanoparticles were characterised using a number of techniques including UV/Vis and inductively coupled plasma-optical emission (ICP-OES) spectroscopies, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and electron paramagnetic resonance (EPR) spectroscopy. Nanocomposites (NCs, 6,7) where the ZnPc (1) was used as the stabiliser, instead of oleic acid and or oleylamine, were also synthesised and characterised.
- Full Text:
- Date Issued: 2013
- Authors: Antunes, Edith M , Rapulenyane, Nomasonto , Ledwaba, Mpho , Litwinski, Christian , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242111 , vital:51002 , xlink:href="https://doi.org/10.1016/j.inoche.2012.12.010"
- Description: A variety of nanoparticles (NPs), including FePt nanoparticles with Fe as the shell (2) or Pt as the shell (3), Pt NPs (4), and FePd (5) were synthesised, characterised and their effect on a zinc phthalocyanine (1) tetra-substituted with a pyridyl-oxy substituent studied using UV/Vis and fluorescence spectroscopy (including time correlated single photon counting, TCSPC). The nanoparticles were characterised using a number of techniques including UV/Vis and inductively coupled plasma-optical emission (ICP-OES) spectroscopies, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and electron paramagnetic resonance (EPR) spectroscopy. Nanocomposites (NCs, 6,7) where the ZnPc (1) was used as the stabiliser, instead of oleic acid and or oleylamine, were also synthesised and characterised.
- Full Text:
- Date Issued: 2013
Think Piece, Naked Science-Avoiding Methodolatry in an Environmental Education Context
- Authors: Price, Leigh
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387264 , vital:68220 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122255"
- Description: Research methodology is significantly political and in this think piece I try to better understand the effect of this politicisation in the production of science. The main focus of the think piece is to identify the dominant methodological discourses and analyse them using techniques borrowed from post-structuralism. From this analysis, I suggest that methodological discourses are reproduced and normalised in much the same way as discourses of, for example, sexuality, and I give examples of this from my experience as a PhD student of environmental education. I also suggest that some transgressive methodologies, such as those associated with postmodernism or participatory research, despite purporting to empower, at times also disempower. Furthermore, all of the methodologies that I analyse are, in one way or another, ‘loaded’; they cloak their agendas. From this analysis, I move towards suggesting an alternative critical realist methodology for environmental education which is naked; its agendas are clearly stated, not least because this epistemology does not lend itself to deception. An important part of this critical realist conception of methodology is the idea of ‘meta-reflexivity’ in which truth is not vulgarly pragmatic or fideistic.
- Full Text:
- Date Issued: 2013
- Authors: Price, Leigh
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387264 , vital:68220 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122255"
- Description: Research methodology is significantly political and in this think piece I try to better understand the effect of this politicisation in the production of science. The main focus of the think piece is to identify the dominant methodological discourses and analyse them using techniques borrowed from post-structuralism. From this analysis, I suggest that methodological discourses are reproduced and normalised in much the same way as discourses of, for example, sexuality, and I give examples of this from my experience as a PhD student of environmental education. I also suggest that some transgressive methodologies, such as those associated with postmodernism or participatory research, despite purporting to empower, at times also disempower. Furthermore, all of the methodologies that I analyse are, in one way or another, ‘loaded’; they cloak their agendas. From this analysis, I move towards suggesting an alternative critical realist methodology for environmental education which is naked; its agendas are clearly stated, not least because this epistemology does not lend itself to deception. An important part of this critical realist conception of methodology is the idea of ‘meta-reflexivity’ in which truth is not vulgarly pragmatic or fideistic.
- Full Text:
- Date Issued: 2013
Third order nonlinear optical properties of phthalocyanines in the presence nanomaterials and in polymer thin films
- Britton, Jonathan, Durmus, Mahmut, Khene, Samson M, Chauke, Vongani, Nyokong, Tebello
- Authors: Britton, Jonathan , Durmus, Mahmut , Khene, Samson M , Chauke, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241772 , vital:50968 , xlink:href="https://doi.org/10.1142/S108842461350003X"
- Description: Third order nonlinear optical properties were determined for phthalocyanine complexes 1–10 containing In, Ga and Zn central metals and tetra- or octa-substituted with benzyloxyphenoxy, phenoxy, tert-butylphenoxy and amino groups at peripheral or non-peripheral positions. The phthalocyanines were embedded in poly (methyl methacrylate) polymer in the presence of CdTe quantum dots. All complexes 1–10 were studied in the presence of CdTe quantum dots and embedded in poly (methyl methacrylate) to form thin films. Complex 3 tetrasubstituted with tert-butylphenoxy groups at non-peripheral positions was also studied in the presence of CdS, CdSe quantum dots, fullerenes, single walled carbon nanotubes. Third order nonlinear optical parameters generally increase for Pcs in the presence of CdTe quantum dots.
- Full Text:
- Date Issued: 2013
- Authors: Britton, Jonathan , Durmus, Mahmut , Khene, Samson M , Chauke, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241772 , vital:50968 , xlink:href="https://doi.org/10.1142/S108842461350003X"
- Description: Third order nonlinear optical properties were determined for phthalocyanine complexes 1–10 containing In, Ga and Zn central metals and tetra- or octa-substituted with benzyloxyphenoxy, phenoxy, tert-butylphenoxy and amino groups at peripheral or non-peripheral positions. The phthalocyanines were embedded in poly (methyl methacrylate) polymer in the presence of CdTe quantum dots. All complexes 1–10 were studied in the presence of CdTe quantum dots and embedded in poly (methyl methacrylate) to form thin films. Complex 3 tetrasubstituted with tert-butylphenoxy groups at non-peripheral positions was also studied in the presence of CdS, CdSe quantum dots, fullerenes, single walled carbon nanotubes. Third order nonlinear optical parameters generally increase for Pcs in the presence of CdTe quantum dots.
- Full Text:
- Date Issued: 2013
Towards a GPU accelerated virtual machine for massively parallel packet classification and filtering
- Nottingham, Alastair, Irwin, Barry V W
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430295 , vital:72681 , https://doi.org/10.1145/2513456.2513504
- Description: This paper considers the application of GPU co-processors to accelerate the analysis of packet data, particularly within extremely large packet traces spanning months or years of traffic. Discussion focuses on the construction, performance and limitations of the experimental GPF (GPU Packet Filter), which employs a prototype massively-parallel protocol-independent multi-match algorithm to rapidly compare packets against multiple arbitrary filters. The paper concludes with a consideration of mechanisms to expand the flexibility and power of the GPF algorithm to construct a fully programmable GPU packet classification virtual machine, which can perform massively parallel classification, data-mining and data-transformation to explore and analyse packet traces. This virtual machine is a component of a larger framework of capture analysis tools which together provide capture indexing, manipulation, filtering and visualisation functions.
- Full Text:
- Date Issued: 2013
Towards a GPU accelerated virtual machine for massively parallel packet classification and filtering
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430295 , vital:72681 , https://doi.org/10.1145/2513456.2513504
- Description: This paper considers the application of GPU co-processors to accelerate the analysis of packet data, particularly within extremely large packet traces spanning months or years of traffic. Discussion focuses on the construction, performance and limitations of the experimental GPF (GPU Packet Filter), which employs a prototype massively-parallel protocol-independent multi-match algorithm to rapidly compare packets against multiple arbitrary filters. The paper concludes with a consideration of mechanisms to expand the flexibility and power of the GPF algorithm to construct a fully programmable GPU packet classification virtual machine, which can perform massively parallel classification, data-mining and data-transformation to explore and analyse packet traces. This virtual machine is a component of a larger framework of capture analysis tools which together provide capture indexing, manipulation, filtering and visualisation functions.
- Full Text:
- Date Issued: 2013
Traditions and new niches: An overview of environmental education curriculum and learning research
- Lotz-Sisitka, Heila, Fien, John, Ketlhoilwe, Mphemelang
- Authors: Lotz-Sisitka, Heila , Fien, John , Ketlhoilwe, Mphemelang
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437323 , vital:73370 , ISBN 9780203813331 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203813331-26/traditions-new-niches-heila-lotz-sisitka-john-fien-mphemelang-ketlhoilwe
- Description: In this chapter we consider the traditions of environmental ed-ucation curriculum and learning research, their relationship to wider education research traditions, and point to new niches for curriculum and learning research, as opened up (in part) 1 through the contributions in this section of the IRHEE. The chapter points to the fact that environmental education re-search seems to primarily be seeking to fulfill a “cultural inno-vation role” in the wider education research landscape, carving out niches and spaces that speak to educational innova-tion/transformation and change. This may in part be due to its “youthfulness” within the more established and traditional edu-cation research landscape and trajectory, but also to its trans-formative intent. Environmental education researchers such as Stevenson (2007) continue to lament the “marginal” or “perma-nently peripheral” status of environmental education and envi-ronmental education research, noting that it is almost impossi-ble to situate effectively within modernist educational para-digms oriented mostly toward reproduction of existing cultures and practices, traditions which continue to characterize formal education institutional settings.
- Full Text:
- Date Issued: 2013
- Authors: Lotz-Sisitka, Heila , Fien, John , Ketlhoilwe, Mphemelang
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437323 , vital:73370 , ISBN 9780203813331 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203813331-26/traditions-new-niches-heila-lotz-sisitka-john-fien-mphemelang-ketlhoilwe
- Description: In this chapter we consider the traditions of environmental ed-ucation curriculum and learning research, their relationship to wider education research traditions, and point to new niches for curriculum and learning research, as opened up (in part) 1 through the contributions in this section of the IRHEE. The chapter points to the fact that environmental education re-search seems to primarily be seeking to fulfill a “cultural inno-vation role” in the wider education research landscape, carving out niches and spaces that speak to educational innova-tion/transformation and change. This may in part be due to its “youthfulness” within the more established and traditional edu-cation research landscape and trajectory, but also to its trans-formative intent. Environmental education researchers such as Stevenson (2007) continue to lament the “marginal” or “perma-nently peripheral” status of environmental education and envi-ronmental education research, noting that it is almost impossi-ble to situate effectively within modernist educational para-digms oriented mostly toward reproduction of existing cultures and practices, traditions which continue to characterize formal education institutional settings.
- Full Text:
- Date Issued: 2013
Two sides of the same coin: extinctions and originations across the Atlantic/Indian Ocean boundary as consequences of the same climate oscillation
- Teske, Peter R, Zardi, Gerardo I, McQuaid, Christopher D, Nicastro, Katy R
- Authors: Teske, Peter R , Zardi, Gerardo I , McQuaid, Christopher D , Nicastro, Katy R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445547 , vital:74399 , https://doi.org/10.21425/F5FBG15591
- Description: Global climate change is correlated not only with variation in extinction rates, but also with speciation rates. However, few mechanisms have been proposed to explain how climate change may have driven the emergence of new evolutionary lineages that eventually became distinct species. Here, we discuss a model of range extension followed by divergence, in which the same climate oscillations that resulted in the extinction of coastal species across the Atlantic/Indian Ocean boundary in southwestern Africa also sowed the seeds of new biodiversity. We present evidence for range extensions and evolutionary divergence from both fossil and genetic data, but also point out the many challenges to the model that need to be addressed before its validity can be accepted.
- Full Text:
- Date Issued: 2013
- Authors: Teske, Peter R , Zardi, Gerardo I , McQuaid, Christopher D , Nicastro, Katy R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445547 , vital:74399 , https://doi.org/10.21425/F5FBG15591
- Description: Global climate change is correlated not only with variation in extinction rates, but also with speciation rates. However, few mechanisms have been proposed to explain how climate change may have driven the emergence of new evolutionary lineages that eventually became distinct species. Here, we discuss a model of range extension followed by divergence, in which the same climate oscillations that resulted in the extinction of coastal species across the Atlantic/Indian Ocean boundary in southwestern Africa also sowed the seeds of new biodiversity. We present evidence for range extensions and evolutionary divergence from both fossil and genetic data, but also point out the many challenges to the model that need to be addressed before its validity can be accepted.
- Full Text:
- Date Issued: 2013
Ultrafast Photodynamics of the Indoline Dye D149 Adsorbed to Porous ZnO in Dye‐Sensitized Solar Cells
- Rohwer, Egmont, Richter, Christoph, Heming, Nadine, Strauch, Kerstin, Litwinski, Christian, Nyokong, Tebello, Schlettwein, Derck, Schwoerer, Heinrich
- Authors: Rohwer, Egmont , Richter, Christoph , Heming, Nadine , Strauch, Kerstin , Litwinski, Christian , Nyokong, Tebello , Schlettwein, Derck , Schwoerer, Heinrich
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242153 , vital:51006 , xlink:href="https://doi.org/10.1002/cphc.201200715"
- Description: We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I−/I3− redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns.
- Full Text:
- Date Issued: 2013
- Authors: Rohwer, Egmont , Richter, Christoph , Heming, Nadine , Strauch, Kerstin , Litwinski, Christian , Nyokong, Tebello , Schlettwein, Derck , Schwoerer, Heinrich
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242153 , vital:51006 , xlink:href="https://doi.org/10.1002/cphc.201200715"
- Description: We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I−/I3− redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns.
- Full Text:
- Date Issued: 2013
Unicorn: A unified communication solution for marginalized communities
- Nyathi, Okelitsi, Terzoli, Alfredo, Tsietsi, Mosiuoa
- Authors: Nyathi, Okelitsi , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430666 , vital:72707 , 10.1109/ICASTech.2013.6707506
- Description: The convergence of previously distinct networks into an All-IP network has resulted in an increase in the number and diversity of devices, channels and communication networks available to users. This has increased the number commu-nication options available and is evidenced by the number of different communication devices owned and services subscribed to. How-ever, this has created complexities that call for proper methods to manage these diverse and in-compatible communication options. The objective of Unified Communication (UC) is to seamlessly integrate the dispar-ate communication channels into a device independent plat-form that can easily be managed by users. Due its focus on a largely urban and highly connected market, UC has not benefited marginalized communities. This paper discusses the design and implementation of Unicorn, a UC solution for a middleware software platform called Teleweaver which was designed to support the development of services for marginalized communities. The solution integrates services from a telecommunication container called Mobicents. It seamlessly amalgamates voice, data and video onto one device independent unified platform easily accessible by users.
- Full Text:
- Date Issued: 2013
- Authors: Nyathi, Okelitsi , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430666 , vital:72707 , 10.1109/ICASTech.2013.6707506
- Description: The convergence of previously distinct networks into an All-IP network has resulted in an increase in the number and diversity of devices, channels and communication networks available to users. This has increased the number commu-nication options available and is evidenced by the number of different communication devices owned and services subscribed to. How-ever, this has created complexities that call for proper methods to manage these diverse and in-compatible communication options. The objective of Unified Communication (UC) is to seamlessly integrate the dispar-ate communication channels into a device independent plat-form that can easily be managed by users. Due its focus on a largely urban and highly connected market, UC has not benefited marginalized communities. This paper discusses the design and implementation of Unicorn, a UC solution for a middleware software platform called Teleweaver which was designed to support the development of services for marginalized communities. The solution integrates services from a telecommunication container called Mobicents. It seamlessly amalgamates voice, data and video onto one device independent unified platform easily accessible by users.
- Full Text:
- Date Issued: 2013
Using a unified invasion framework to characterize Africa’s first loricariid catfish invasion
- Jones, Roy W, Weyl, Olaf L F, Hill, Martin P, Swartz, Ernst R
- Authors: Jones, Roy W , Weyl, Olaf L F , Hill, Martin P , Swartz, Ernst R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418081 , vital:71507 , xlink:href="https://doi.org/10.1007/s10530-013-0438-7"
- Description: This paper presents evidence of establishment of a loricariid population in the Nseleni River in South Africa and uses a unified framework to determine its invasion stage. Specimens were identified morphologically as Pterygioplichthys disjunctivus (Weber 1991), but genetic barcoding results indicated close association with specimens that may have a hybrid history. The species was introduced into South Africa via the pet trade and the first record of introduction into the wild was in 2004. Samples collected in 2011 and 2012 demonstrated that there were multiple length cohorts in the population including juveniles (12–130 mm total length TL) and large (>300 mm TL) adult fish. Gonadal assessment of adults demonstrated the presence of reproduction capable specimens. The concurrent occurrence of mature adults and juvenile fish demonstrated establishment. Locality records indicate that P. disjunctivus has already spread between two rivers through an inter basin water transfer. Using a unified framework for invasions this invasion was categorized as a self-sustaining population in the wild with individuals surviving and reproducing a significant distance from their original point of introduction. Containment is suggested as potential management strategy.
- Full Text:
- Date Issued: 2013
- Authors: Jones, Roy W , Weyl, Olaf L F , Hill, Martin P , Swartz, Ernst R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418081 , vital:71507 , xlink:href="https://doi.org/10.1007/s10530-013-0438-7"
- Description: This paper presents evidence of establishment of a loricariid population in the Nseleni River in South Africa and uses a unified framework to determine its invasion stage. Specimens were identified morphologically as Pterygioplichthys disjunctivus (Weber 1991), but genetic barcoding results indicated close association with specimens that may have a hybrid history. The species was introduced into South Africa via the pet trade and the first record of introduction into the wild was in 2004. Samples collected in 2011 and 2012 demonstrated that there were multiple length cohorts in the population including juveniles (12–130 mm total length TL) and large (>300 mm TL) adult fish. Gonadal assessment of adults demonstrated the presence of reproduction capable specimens. The concurrent occurrence of mature adults and juvenile fish demonstrated establishment. Locality records indicate that P. disjunctivus has already spread between two rivers through an inter basin water transfer. Using a unified framework for invasions this invasion was categorized as a self-sustaining population in the wild with individuals surviving and reproducing a significant distance from their original point of introduction. Containment is suggested as potential management strategy.
- Full Text:
- Date Issued: 2013
Using assessment strategically to gestate a student thesis
- Authors: Grant, Carolyn
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281164 , vital:55698 , xlink:href="https://hdl.handle.net/10520/EJC153523"
- Description: In the context of higher education in South Africa and drawing on the author's experience as a lecturer in two higher education institutions (HEIs), this article presents her attempts to bring together - and into balance - teaching, supervision and research in an endeavour to offer a transformative learning experience for her post graduate students. It does this by foregrounding student assessment in the Master of Education (MEd) degree in the field of Educational Leadership and Management (ELM) where the development of a half thesis, underpinned by research, stands as the evidence of success. The author suggests that the MEd (ELM) degree be conceptualised differently in order that the half thesis be permitted to gestate over a two-year period. Within this conceptualisation, she argues that inspired teaching and meaningful research is best attained through a community of learning approach which seeks to foreground participatory learning, the advancement of scholarly discourse and the development of student agency. Through the use of a case study, the author provides evidence to suggest that a range of authentic assessment strategies which are purposeful and in alignment with the teaching strategies, the content and the intended outcomes of the qualification being taught are essential. She further argues that well-crafted, formative, recursive and sustainable feedback is an essential part of the gestation process.
- Full Text:
- Date Issued: 2013
- Authors: Grant, Carolyn
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281164 , vital:55698 , xlink:href="https://hdl.handle.net/10520/EJC153523"
- Description: In the context of higher education in South Africa and drawing on the author's experience as a lecturer in two higher education institutions (HEIs), this article presents her attempts to bring together - and into balance - teaching, supervision and research in an endeavour to offer a transformative learning experience for her post graduate students. It does this by foregrounding student assessment in the Master of Education (MEd) degree in the field of Educational Leadership and Management (ELM) where the development of a half thesis, underpinned by research, stands as the evidence of success. The author suggests that the MEd (ELM) degree be conceptualised differently in order that the half thesis be permitted to gestate over a two-year period. Within this conceptualisation, she argues that inspired teaching and meaningful research is best attained through a community of learning approach which seeks to foreground participatory learning, the advancement of scholarly discourse and the development of student agency. Through the use of a case study, the author provides evidence to suggest that a range of authentic assessment strategies which are purposeful and in alignment with the teaching strategies, the content and the intended outcomes of the qualification being taught are essential. She further argues that well-crafted, formative, recursive and sustainable feedback is an essential part of the gestation process.
- Full Text:
- Date Issued: 2013
Weevil borne microbes contribute as much to the reduction of photosynthesis in water hyacinth as does herbivory
- Venter, Nic, Hill, Martin P, Hutchinson, Sarah-Leigh, Ripley, Bradford S
- Authors: Venter, Nic , Hill, Martin P , Hutchinson, Sarah-Leigh , Ripley, Bradford S
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423573 , vital:72073 , xlink:href="https://doi.org/10.1016/j.biocontrol.2012.10.011"
- Description: Arthropods released for weed biocontrol can have effects other than simply removing biomass and frequently decrease photosynthetic rate more than can be attributed to the mere loss of photosynthetic surface area. Some of this effect may result because biological control agents facilitate the transfer and ingress of deleterious microbes into plant tissues on which they feed. We evaluated this facilitation effect using water hyacinth (Eichhornia crassipes) and a weevil (Neochetina eichhorniae) and compared the reductions in photosynthetic rates between leaves subject to herbivory by adult weevils sterilized with 3.5% chlorine bleach, to those that were unsterilized. The results showed that weevils carried both fungi and bacteria, transferred these to leaves on which they fed, and that microbes and biomass removal contributed almost equally to the 37% decrease in photosynthetic productivity. Hence, maximising the effectiveness of using arthropods that damage leaf surfaces for biocontrol requires the presence of microorganisms that are deleterious to plants.
- Full Text:
- Date Issued: 2013
- Authors: Venter, Nic , Hill, Martin P , Hutchinson, Sarah-Leigh , Ripley, Bradford S
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423573 , vital:72073 , xlink:href="https://doi.org/10.1016/j.biocontrol.2012.10.011"
- Description: Arthropods released for weed biocontrol can have effects other than simply removing biomass and frequently decrease photosynthetic rate more than can be attributed to the mere loss of photosynthetic surface area. Some of this effect may result because biological control agents facilitate the transfer and ingress of deleterious microbes into plant tissues on which they feed. We evaluated this facilitation effect using water hyacinth (Eichhornia crassipes) and a weevil (Neochetina eichhorniae) and compared the reductions in photosynthetic rates between leaves subject to herbivory by adult weevils sterilized with 3.5% chlorine bleach, to those that were unsterilized. The results showed that weevils carried both fungi and bacteria, transferred these to leaves on which they fed, and that microbes and biomass removal contributed almost equally to the 37% decrease in photosynthetic productivity. Hence, maximising the effectiveness of using arthropods that damage leaf surfaces for biocontrol requires the presence of microorganisms that are deleterious to plants.
- Full Text:
- Date Issued: 2013
X-ray photoelectron spectroscopy analysis of the effect of alkyl-and arylthio substituents on manganese phthalocyanines for self-assembled monolayer formation on gold
- Coates, Megan, Nyokong, Tebello
- Authors: Coates, Megan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190490 , vital:44999 , xlink:href="https://doi.org/10.1016/j.elecom.2013.03.019"
- Description: Self-assembled monolayers of an octa-substituted alkylthio and arylthio manganese phthalocyanines were formed on gold. X-ray photoelectron spectroscopy was used to analyse both of the phthalocyanine layers on gold. Approximately 60% of the sulphur groups in the aryl substituted-SAM surface were bound to gold through the cleavage of the C S bond, as opposed to only 37% for the alkyl substituted-SAM.
- Full Text:
- Date Issued: 2013
- Authors: Coates, Megan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190490 , vital:44999 , xlink:href="https://doi.org/10.1016/j.elecom.2013.03.019"
- Description: Self-assembled monolayers of an octa-substituted alkylthio and arylthio manganese phthalocyanines were formed on gold. X-ray photoelectron spectroscopy was used to analyse both of the phthalocyanine layers on gold. Approximately 60% of the sulphur groups in the aryl substituted-SAM surface were bound to gold through the cleavage of the C S bond, as opposed to only 37% for the alkyl substituted-SAM.
- Full Text:
- Date Issued: 2013