Elucidating Latent Mechanistic Complexity in Competing Acid-Catalyzed Reactions of Salicylaldehyde-Derived Baylis–Hillman Adducts
- Olomola, Temitope O, Klein, Rosalyn, Caira, Mino, R, Kaye, Perry T
- Authors: Olomola, Temitope O , Klein, Rosalyn , Caira, Mino, R , Kaye, Perry T
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442596 , vital:74010 , https://doi.org/10.1021/acs.joc.5b02372
- Description: 1H NMR-based kinetic studies have revealed the latent mechanistic complexity of deceptively simple hydrochloric acid-catalyzed reactions of salicylaldehyde-derived Baylis–Hillman adducts. Reactions conducted at 0 °C afforded 2-(chloromethyl)cinnamic acid derivatives as the major products and the corresponding 3-(chloromethyl)coumarin derivatives as the minor products. In reactions conducted in refluxing acetic acid, however, the 3-(chloromethyl)coumarin derivatives are the sole products. Variable-temperature 1H NMR analysis permitted the determination of the rate constants and kinetic parameters involved in the pseudo-first-order formation of (Z)-2-(chloromethyl)-3-(2-hydroxyphenyl)-2-propenoic acid. The kinetic data clearly preclude the operation of classical kinetic versus thermodynamic control and indicate the operation of three independent reaction pathways. Theoretical studies of these pathways undertaken at the B3LYP/6-31G(d) level permitted rationalization of the experimental data and provided insights into the possible mechanism of the enzymic E–Z isomerization and cyclization of (E)-cinnamic acid analogues to afford coumarins.
- Full Text:
- Date Issued: 2016
- Authors: Olomola, Temitope O , Klein, Rosalyn , Caira, Mino, R , Kaye, Perry T
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442596 , vital:74010 , https://doi.org/10.1021/acs.joc.5b02372
- Description: 1H NMR-based kinetic studies have revealed the latent mechanistic complexity of deceptively simple hydrochloric acid-catalyzed reactions of salicylaldehyde-derived Baylis–Hillman adducts. Reactions conducted at 0 °C afforded 2-(chloromethyl)cinnamic acid derivatives as the major products and the corresponding 3-(chloromethyl)coumarin derivatives as the minor products. In reactions conducted in refluxing acetic acid, however, the 3-(chloromethyl)coumarin derivatives are the sole products. Variable-temperature 1H NMR analysis permitted the determination of the rate constants and kinetic parameters involved in the pseudo-first-order formation of (Z)-2-(chloromethyl)-3-(2-hydroxyphenyl)-2-propenoic acid. The kinetic data clearly preclude the operation of classical kinetic versus thermodynamic control and indicate the operation of three independent reaction pathways. Theoretical studies of these pathways undertaken at the B3LYP/6-31G(d) level permitted rationalization of the experimental data and provided insights into the possible mechanism of the enzymic E–Z isomerization and cyclization of (E)-cinnamic acid analogues to afford coumarins.
- Full Text:
- Date Issued: 2016
Encompassing the relative non-target risks from agents and their alien plant targets in biological control assessments
- Downey, Paul O, Paterson, Iain D
- Authors: Downey, Paul O , Paterson, Iain D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417940 , vital:71496 , xlink:href="https://doi.org/10.1007/s10526-016-9744-1"
- Description: Criticisms about the safety of biological control of alien plants has resulted in a risk-averse approach, where the risks posed by the agent are paramount and the risks posed by the alien plant are neglected. We argue that the risk associated with non-target damage from agents needs to be assessed relative to that of their target alien plants. A literature review of the non-target risks associated with biological control agents was undertaken in terms of the risk to native species from agents relative to the risk to native species from their alien plant targets. We then developed a framework that compares the consequence with the likelihood of non-target damage for both agents and their targets to provide an overall risk rating. Assessments of the risk of damage from both agents and their target alien plants will enable researchers, managers and policy makers to better assess the risks from biological control.
- Full Text:
- Date Issued: 2016
- Authors: Downey, Paul O , Paterson, Iain D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417940 , vital:71496 , xlink:href="https://doi.org/10.1007/s10526-016-9744-1"
- Description: Criticisms about the safety of biological control of alien plants has resulted in a risk-averse approach, where the risks posed by the agent are paramount and the risks posed by the alien plant are neglected. We argue that the risk associated with non-target damage from agents needs to be assessed relative to that of their target alien plants. A literature review of the non-target risks associated with biological control agents was undertaken in terms of the risk to native species from agents relative to the risk to native species from their alien plant targets. We then developed a framework that compares the consequence with the likelihood of non-target damage for both agents and their targets to provide an overall risk rating. Assessments of the risk of damage from both agents and their target alien plants will enable researchers, managers and policy makers to better assess the risks from biological control.
- Full Text:
- Date Issued: 2016
Enhanced nonlinear optical responses of zinc diaminopyrimidin-2-ylthio phthalocyanine conjugated to AgxAuy alloy nanoparticles
- Bankole, Owolabi M, Osifeko, Olawale, Nyokong, Tebello
- Authors: Bankole, Owolabi M , Osifeko, Olawale , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240382 , vital:50829 , xlink:href="https://doi.org/10.1016/j.jphotochem.2016.06.025"
- Description: In this article, the photophysical and nonlinear optical (NLO) characterizations of diaminopyrimidin-2-ylthio phthalocyaninatozinc (II) (2) before and after conjugation to AgxAuy nano-alloys are discussed. Phthalocyanines-AgxAuy (2-AgxAuy) composites showed enhanced triplet state and nonlinear optical behaviour when compared to free phthalocyanine. Optical limiting (OL) responses of the samples were evaluated using Z-scan technique at 532 nm and 10 ns in dimethyl sulfoxide. Reverse saturable absorption (RSA), which is a direct consequence of triplet absorption of already excited molecules was observed as the dominant mechanism responsible for nonlinearity of the samples. By virtue of the magnitude of absorption coefficients and other NLO optical parameters estimated in this work, 2-AgxAuy composites were found to exhibit stronger optical limiting responses than unconjugated phthalocyanine. The large third-order susceptibilities of the composites make them suitable materials for attenuating modern laser radiations, and also found useful in various optical applications.
- Full Text:
- Date Issued: 2016
- Authors: Bankole, Owolabi M , Osifeko, Olawale , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240382 , vital:50829 , xlink:href="https://doi.org/10.1016/j.jphotochem.2016.06.025"
- Description: In this article, the photophysical and nonlinear optical (NLO) characterizations of diaminopyrimidin-2-ylthio phthalocyaninatozinc (II) (2) before and after conjugation to AgxAuy nano-alloys are discussed. Phthalocyanines-AgxAuy (2-AgxAuy) composites showed enhanced triplet state and nonlinear optical behaviour when compared to free phthalocyanine. Optical limiting (OL) responses of the samples were evaluated using Z-scan technique at 532 nm and 10 ns in dimethyl sulfoxide. Reverse saturable absorption (RSA), which is a direct consequence of triplet absorption of already excited molecules was observed as the dominant mechanism responsible for nonlinearity of the samples. By virtue of the magnitude of absorption coefficients and other NLO optical parameters estimated in this work, 2-AgxAuy composites were found to exhibit stronger optical limiting responses than unconjugated phthalocyanine. The large third-order susceptibilities of the composites make them suitable materials for attenuating modern laser radiations, and also found useful in various optical applications.
- Full Text:
- Date Issued: 2016
Enhancing Life Sciences Teachers’ Biodiversity Knowledge
- Authors: Tshiningayamwe, Sirkka A N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387991 , vital:68296 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/152733"
- Description: In the last two decades, South Africa has made efforts to integrate biodiversity content in its Life Sciences curriculum; however its implementation lacks systemic coherence. This is due to ineffective professional development approaches. This paper provides insights into how Life Sciences teachers in the Eastern Cape can be supported through professional learning communities (PLCs) as a potential approach to enhancing their biodiversity knowledge. PLCs are communities that provide the setting and necessary support for groups of classroom teachers to participate collectively in determining their own developmental trajectories, and to set up activities that will drive their development. The case study presented in this paper is part of a broader qualitative PhD study which explored the functionings and conversion factors in biodiversity teacher PLCs in South Africa. Drawing on teachers’ and facilitators’ experiences and the observation of the PLC approaches, the capability approach was used to analyse the functionings and conversion factors that enhance teachers’ biodiversity knowledge. The paper highlights that for PLCs to be effective approaches for professional development, they need to be aligned to teachers’ valued functionings. It also reveals that different conversion factors enable teachers’ achievements of valued functionings in the PLC. The paper aims to contribute to wider policies on capacity building for teachers.
- Full Text:
- Date Issued: 2016
- Authors: Tshiningayamwe, Sirkka A N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387991 , vital:68296 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/152733"
- Description: In the last two decades, South Africa has made efforts to integrate biodiversity content in its Life Sciences curriculum; however its implementation lacks systemic coherence. This is due to ineffective professional development approaches. This paper provides insights into how Life Sciences teachers in the Eastern Cape can be supported through professional learning communities (PLCs) as a potential approach to enhancing their biodiversity knowledge. PLCs are communities that provide the setting and necessary support for groups of classroom teachers to participate collectively in determining their own developmental trajectories, and to set up activities that will drive their development. The case study presented in this paper is part of a broader qualitative PhD study which explored the functionings and conversion factors in biodiversity teacher PLCs in South Africa. Drawing on teachers’ and facilitators’ experiences and the observation of the PLC approaches, the capability approach was used to analyse the functionings and conversion factors that enhance teachers’ biodiversity knowledge. The paper highlights that for PLCs to be effective approaches for professional development, they need to be aligned to teachers’ valued functionings. It also reveals that different conversion factors enable teachers’ achievements of valued functionings in the PLC. The paper aims to contribute to wider policies on capacity building for teachers.
- Full Text:
- Date Issued: 2016
Enigmatic tissue in the orobranchial chamber of cardinalfishes of the genus Siphamia (Perciformes, Apogonidae)
- Gon, Ofer, Pinchuck, Shirley C
- Authors: Gon, Ofer , Pinchuck, Shirley C
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443297 , vital:74106 , https://hdl.handle.net/10520/EJC196540
- Description: An unusual tissue covering the tongue and occasionally part of the gill chamber of many species of the Indo-Pacific cardinalfish genus Siphamia is described and compared with an earlier description of a similar tissue found in the cichlid species Alcolapia grahami inhabiting lakes of the African Rift Valley. Species of both genera are mouth brooders. The Siphamia tissue is globular and its cells are oblong, whereas the A. grahami tissue is single-layered, with larger, columnar cells. The tissues of both have the characteristics of a mucosa and show evidence of active synthesis. While ion regulation has been proposed for the A. grahami tissue, the function of the Siphamia tissue is unknown, but a role in feeding, or antibiotic or appetite-suppressing functions have been suggested.
- Full Text:
- Date Issued: 2016
- Authors: Gon, Ofer , Pinchuck, Shirley C
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443297 , vital:74106 , https://hdl.handle.net/10520/EJC196540
- Description: An unusual tissue covering the tongue and occasionally part of the gill chamber of many species of the Indo-Pacific cardinalfish genus Siphamia is described and compared with an earlier description of a similar tissue found in the cichlid species Alcolapia grahami inhabiting lakes of the African Rift Valley. Species of both genera are mouth brooders. The Siphamia tissue is globular and its cells are oblong, whereas the A. grahami tissue is single-layered, with larger, columnar cells. The tissues of both have the characteristics of a mucosa and show evidence of active synthesis. While ion regulation has been proposed for the A. grahami tissue, the function of the Siphamia tissue is unknown, but a role in feeding, or antibiotic or appetite-suppressing functions have been suggested.
- Full Text:
- Date Issued: 2016
Entomopathogenic fungi as control agents of Thaumatotibia leucotreta in citrus orchards: field efficacy and persistence
- Coombes, Candice A, Hill, Martin P, Moore, Sean D, Dames, Joanna F
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417956 , vital:71497 , xlink:href="https://doi.org/10.1007/s10526-016-9756-x"
- Description: Entomopathogenic fungal isolates Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) strain G Ar 17 B3 and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) strain FCM Ar 23 B3 have been identified as effective control agents of the important citrus pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) wandering fifth instars under laboratory conditions. This study is the first report on the ability of these isolates to persist and reduce T. leucotreta infestation in commercial citrus orchards in South Africa. A reduction in pest infestation of between 28 and 82 % upon trial completion was reported. Both isolates were recovered from soil samples collected five months post-application with high host density and moderate to high soil moisture favouring recovery. Low soil moisture negatively influenced the persistence of both isolates and the control efficiency of B. bassiana. These results provide evidence and support for the future use of these isolates against T. leucotreta thus warranting further investigation.
- Full Text:
- Date Issued: 2016
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417956 , vital:71497 , xlink:href="https://doi.org/10.1007/s10526-016-9756-x"
- Description: Entomopathogenic fungal isolates Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) strain G Ar 17 B3 and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) strain FCM Ar 23 B3 have been identified as effective control agents of the important citrus pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) wandering fifth instars under laboratory conditions. This study is the first report on the ability of these isolates to persist and reduce T. leucotreta infestation in commercial citrus orchards in South Africa. A reduction in pest infestation of between 28 and 82 % upon trial completion was reported. Both isolates were recovered from soil samples collected five months post-application with high host density and moderate to high soil moisture favouring recovery. Low soil moisture negatively influenced the persistence of both isolates and the control efficiency of B. bassiana. These results provide evidence and support for the future use of these isolates against T. leucotreta thus warranting further investigation.
- Full Text:
- Date Issued: 2016
Expanding reproductive justice through a supportability reparative justice framework: the case of abortion in South Africa
- Authors: Macleod, Catriona I
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443680 , vital:74143 , xlink:href="https://doi.org/10.1080/13691058.2018.1447687"
- Description: Theoretical refinement of the concept of reproductive justice has been called for. In this paper, I propose the use of a supportability reparative justice approach. Drawing on intra-categorical intersectionality, the supportability aspect starts from the event of a pregnancy to unravel the interwoven embodied and social realities implicated in women experiencing pregnancy as personally supportable/unsupportable, and socially supported/unsupported. The reparative justice aspect highlights the need for social repair in the case of unsupportable pregnancies and relies on Ernesto Verdeja’s critical theory of reparative justice in which he outlines four reparative dimensions. Using abortion within the South African context, I show how this framework may be put to use: (1) the facilitation of autonomous decision-making (individual material dimension) requires understanding women within context, and less emphasis on individual-driven ‘choice’; (2) the provision of legal, safe state-sponsored healthcare resources (collective material dimension) demands political will and abortion service provision to be regarded as a moral as well as a healthcare priority; (3) overcoming stigma and the spoiled identities (collective symbolic dimension) requires significant feminist action to deconstruct negative discourses and to foreground positive narratives; and (4) understanding individual lived experiences (individual symbolic dimension) means deep listening within the social dynamics of particular contexts.
- Full Text:
- Date Issued: 2016
- Authors: Macleod, Catriona I
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443680 , vital:74143 , xlink:href="https://doi.org/10.1080/13691058.2018.1447687"
- Description: Theoretical refinement of the concept of reproductive justice has been called for. In this paper, I propose the use of a supportability reparative justice approach. Drawing on intra-categorical intersectionality, the supportability aspect starts from the event of a pregnancy to unravel the interwoven embodied and social realities implicated in women experiencing pregnancy as personally supportable/unsupportable, and socially supported/unsupported. The reparative justice aspect highlights the need for social repair in the case of unsupportable pregnancies and relies on Ernesto Verdeja’s critical theory of reparative justice in which he outlines four reparative dimensions. Using abortion within the South African context, I show how this framework may be put to use: (1) the facilitation of autonomous decision-making (individual material dimension) requires understanding women within context, and less emphasis on individual-driven ‘choice’; (2) the provision of legal, safe state-sponsored healthcare resources (collective material dimension) demands political will and abortion service provision to be regarded as a moral as well as a healthcare priority; (3) overcoming stigma and the spoiled identities (collective symbolic dimension) requires significant feminist action to deconstruct negative discourses and to foreground positive narratives; and (4) understanding individual lived experiences (individual symbolic dimension) means deep listening within the social dynamics of particular contexts.
- Full Text:
- Date Issued: 2016
Fluorescence behavior of nanoconjugates of graphene quantum dots and zinc phthalocyanines
- Achadu, Ojodomo John, Uddin, Imran, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Uddin, Imran , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188777 , vital:44784 , xlink:href="https://doi.org/10.1016/j.jphotochem.2015.11.006"
- Description: Graphene quantum dots (GQDs) and zinc phthalocyanines interactions in different modes (covalent and non-covalent) are reported in this study. GQDs were covalently attached to the following complexes: zinc tetraamino phthalocyanine (ZnTAPc) via amide coupling, zinc tetracarboxyphenoxy Pc (ZnTCPPc) (π–π interaction) and cationic zinc tetrapyridiloxy Pc (ZnTmPyPc) (ionic interaction). GQDs fluorescence was quenched in the presence of the ZnPc derivatives. The nanoensembles of GQDs–ZnPcs showed stimulated emissions of the ZnPcs. The suggested quenching mechanism is through Förster resonance energy transfer (FRET). These novel nanoensembles hold promise for various optical and luminescence based applications.
- Full Text:
- Date Issued: 2016
- Authors: Achadu, Ojodomo John , Uddin, Imran , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188777 , vital:44784 , xlink:href="https://doi.org/10.1016/j.jphotochem.2015.11.006"
- Description: Graphene quantum dots (GQDs) and zinc phthalocyanines interactions in different modes (covalent and non-covalent) are reported in this study. GQDs were covalently attached to the following complexes: zinc tetraamino phthalocyanine (ZnTAPc) via amide coupling, zinc tetracarboxyphenoxy Pc (ZnTCPPc) (π–π interaction) and cationic zinc tetrapyridiloxy Pc (ZnTmPyPc) (ionic interaction). GQDs fluorescence was quenched in the presence of the ZnPc derivatives. The nanoensembles of GQDs–ZnPcs showed stimulated emissions of the ZnPcs. The suggested quenching mechanism is through Förster resonance energy transfer (FRET). These novel nanoensembles hold promise for various optical and luminescence based applications.
- Full Text:
- Date Issued: 2016
Fluorescence properties of alloyed ZnSeS quantum dots overcoated with ZnTe and ZnTe/ZnS shells
- Adegoke, Oluwasesan, Mashazi, Philani N, Nyokong, Tebello, Forbes, Patricia B C
- Authors: Adegoke, Oluwasesan , Mashazi, Philani N , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240754 , vital:50868 , xlink:href="https://doi.org/10.1016/j.optmat.2016.02.024"
- Description: Fluorescent alloyed ternary ZnSeS quantum dots (QDs) have been synthesized via the pyrolysis of organometallic precursors. The effects of passivation of ZnTe and ZnTe/ZnS shells on the optical properties of the ternary alloyed ZnSeS core have been studied. A ligand exchange reaction using L-cysteine as a capping ligand was used to obtain water-soluble nanocrystals. The nanocrystals were each characterized by UV/vis absorption and fluorescence spectroscopy, transmission electron microscopy, X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The photoluminescence (PL) quantum yield (QY) of alloyed ZnSeS QDs was 14% and this value increased to 27% when ZnTe was overcoated around the surface but further coating with a ZnS shell decreased the PL QY slightly to 24%. This implies that ZnTe shell suppressed non-radiative recombination exciton states in the alloyed core while further layering with a ZnS shell offered no further improvement in suppressing the defect states. XPS analysis confirmed the presence of the first shell layering but showed a weakened intensity signal of S (2p) and Se (3d) for the ZnSeS/ZnTe/ZnS QDs. Our work demonstrates for the first time that shell passivation of alloyed Zn-based QDs can offer improved optical properties. We hope the optical information presented in this work will be useful in the selection of alloyed Zn-based QDs appropriate for the intended application.
- Full Text:
- Date Issued: 2016
- Authors: Adegoke, Oluwasesan , Mashazi, Philani N , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240754 , vital:50868 , xlink:href="https://doi.org/10.1016/j.optmat.2016.02.024"
- Description: Fluorescent alloyed ternary ZnSeS quantum dots (QDs) have been synthesized via the pyrolysis of organometallic precursors. The effects of passivation of ZnTe and ZnTe/ZnS shells on the optical properties of the ternary alloyed ZnSeS core have been studied. A ligand exchange reaction using L-cysteine as a capping ligand was used to obtain water-soluble nanocrystals. The nanocrystals were each characterized by UV/vis absorption and fluorescence spectroscopy, transmission electron microscopy, X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The photoluminescence (PL) quantum yield (QY) of alloyed ZnSeS QDs was 14% and this value increased to 27% when ZnTe was overcoated around the surface but further coating with a ZnS shell decreased the PL QY slightly to 24%. This implies that ZnTe shell suppressed non-radiative recombination exciton states in the alloyed core while further layering with a ZnS shell offered no further improvement in suppressing the defect states. XPS analysis confirmed the presence of the first shell layering but showed a weakened intensity signal of S (2p) and Se (3d) for the ZnSeS/ZnTe/ZnS QDs. Our work demonstrates for the first time that shell passivation of alloyed Zn-based QDs can offer improved optical properties. We hope the optical information presented in this work will be useful in the selection of alloyed Zn-based QDs appropriate for the intended application.
- Full Text:
- Date Issued: 2016
Fundisa for Change teacher professional development programme
- Authors: Tshiningayamwe, Sirkka A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432999 , vital:72922 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-vol-43.pdf"
- Description: Environment and sustainability content has been integrated into the South African curricula documents, including the past ones. This integration was followed by initiatives which aimed at supporting teachers to implement environmental knowledge and action in the curriculum. For example, the Learning for Sustainability project was piloted in Gauteng and Mpumalanga province between the year 1997 and 2000. The project followed a three pillar approach of integrating environmental education in the curriculum: teacher development, curriculum development and materials development. As part of the project, a spiral model approach to teacher professional development was introduced.
- Full Text:
- Date Issued: 2016
- Authors: Tshiningayamwe, Sirkka A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432999 , vital:72922 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-vol-43.pdf"
- Description: Environment and sustainability content has been integrated into the South African curricula documents, including the past ones. This integration was followed by initiatives which aimed at supporting teachers to implement environmental knowledge and action in the curriculum. For example, the Learning for Sustainability project was piloted in Gauteng and Mpumalanga province between the year 1997 and 2000. The project followed a three pillar approach of integrating environmental education in the curriculum: teacher development, curriculum development and materials development. As part of the project, a spiral model approach to teacher professional development was introduced.
- Full Text:
- Date Issued: 2016
Generation of New Ecotoxicity Data for Salts Using Indigenous South African Freshwater Macroinvertebrate: Updating the National Salts Toxicity Database
- Mensah, Paul K, Mgaba, Ntombekhaya, Griffin, Neil J, Odume, Oghenekaro N, Palmer, Carolyn G
- Authors: Mensah, Paul K , Mgaba, Ntombekhaya , Griffin, Neil J , Odume, Oghenekaro N , Palmer, Carolyn G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437854 , vital:73417 , ISBN 978-1-4312-0747-3 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20353.pdf
- Description: Scherman and Palmer (2013) reviewed the historical and current trends of Environmental Water Quality (EWQ) in South Africa. Based on the review, they identified research gaps for which they proposed a co-ordinated set of projects that need to be commissioned and executed to fill these gaps. These co-ordinated set of projects include update of TEACHA (Tool for Ecological Aquatic Chemical Habitat Assessment); update of the national salt toxicity database; integration of Resource Directed Measures (RDM) components (ie Ecological Reserve, Re-source Quality Objectives (RQOs) and Classification); integrating water quality and quantity; evaluation of the RDM participatory process based on research and current understandings of complex social-ecological systems and ecosystem services; and integrating RDM and SDC (Source Direct Control) to ensure coherent link between the two. The overarching aim of the above set of projects is to support implementa-tion of the National Water Resource Strategy 2 (NWRS2). Therefore, the main objective of this project to contribute to addressing the second research gap listed above (ie updating the national salt toxicity data-base). Noting that the database contains only data on single salts with nothing on salt mixtures, the project also generated binary salt mixtures data for the database, in addition to generating data for single salts.
- Full Text:
- Date Issued: 2016
- Authors: Mensah, Paul K , Mgaba, Ntombekhaya , Griffin, Neil J , Odume, Oghenekaro N , Palmer, Carolyn G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437854 , vital:73417 , ISBN 978-1-4312-0747-3 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20353.pdf
- Description: Scherman and Palmer (2013) reviewed the historical and current trends of Environmental Water Quality (EWQ) in South Africa. Based on the review, they identified research gaps for which they proposed a co-ordinated set of projects that need to be commissioned and executed to fill these gaps. These co-ordinated set of projects include update of TEACHA (Tool for Ecological Aquatic Chemical Habitat Assessment); update of the national salt toxicity database; integration of Resource Directed Measures (RDM) components (ie Ecological Reserve, Re-source Quality Objectives (RQOs) and Classification); integrating water quality and quantity; evaluation of the RDM participatory process based on research and current understandings of complex social-ecological systems and ecosystem services; and integrating RDM and SDC (Source Direct Control) to ensure coherent link between the two. The overarching aim of the above set of projects is to support implementa-tion of the National Water Resource Strategy 2 (NWRS2). Therefore, the main objective of this project to contribute to addressing the second research gap listed above (ie updating the national salt toxicity data-base). Noting that the database contains only data on single salts with nothing on salt mixtures, the project also generated binary salt mixtures data for the database, in addition to generating data for single salts.
- Full Text:
- Date Issued: 2016
Graphene quantum dots functionalized with 4-amino-2, 2, 6, 6-tetramethylpiperidine-N-oxide as fluorescence “turn-on” nanosensors
- Achadu, Ojodomo J, Britton, Jonathan, Nyokong, Tebello
- Authors: Achadu, Ojodomo J , Britton, Jonathan , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239854 , vital:50773 , xlink:href="https://doi.org/10.1007/s10895-016-1916-y"
- Description: In this study, we report on the fabrication of simple and rapid graphene quantum dots (GQDs)-based fluorescence “turn-ON” nanoprobes for sensitive and selective detection of ascorbic acid (AA). Pristine GQDs and S and N co-doped-GQDs (SN-GQDs) were functionalized with 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4-amino-TEMPO, a nitroxide free radical). The nitroxide free radicals efficiently quenched the fluorescence of the GQDs and upon interaction of the nanoconjugates with ascorbic acid, the quenched fluorescence was restored. The linear ranges recorded were 0.5–5.7 μM and 0.1–5.5 μM for GQDs-4-amino-TEMPO and SN-GQDs-4amino-TEMPO nanoprobes, respectively. Limits of detection were found to be 60 nM and 84 nM for SN-GQDS-4-amino-TEMPO and GQDs-4-amino-TEMPO for AA detection, respectively. This novel fluorescence “turn-ON” technique showed to be highly rapid and selective towards AA detection.
- Full Text:
- Date Issued: 2016
- Authors: Achadu, Ojodomo J , Britton, Jonathan , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239854 , vital:50773 , xlink:href="https://doi.org/10.1007/s10895-016-1916-y"
- Description: In this study, we report on the fabrication of simple and rapid graphene quantum dots (GQDs)-based fluorescence “turn-ON” nanoprobes for sensitive and selective detection of ascorbic acid (AA). Pristine GQDs and S and N co-doped-GQDs (SN-GQDs) were functionalized with 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4-amino-TEMPO, a nitroxide free radical). The nitroxide free radicals efficiently quenched the fluorescence of the GQDs and upon interaction of the nanoconjugates with ascorbic acid, the quenched fluorescence was restored. The linear ranges recorded were 0.5–5.7 μM and 0.1–5.5 μM for GQDs-4-amino-TEMPO and SN-GQDs-4amino-TEMPO nanoprobes, respectively. Limits of detection were found to be 60 nM and 84 nM for SN-GQDS-4-amino-TEMPO and GQDs-4-amino-TEMPO for AA detection, respectively. This novel fluorescence “turn-ON” technique showed to be highly rapid and selective towards AA detection.
- Full Text:
- Date Issued: 2016
HealthMessenger: an e-Health service to support ICT deployments in poor areas
- Gremu, Chikumbutso, Terzoli, Alfredo, Tsietsi, Mosiuoa
- Authors: Gremu, Chikumbutso , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430609 , vital:72703 , 10.1109/ISTAFRICA.2016.7530632
- Description: Development and implementation of appropriate e-services as well as revenue generation are key to deploying and sustaining ICT installa-tions in poor areas in developing countries. The area of e-Health is a promising area for e-Services that are important to populations in poor areas and health service organisations that are already spending mon-ey on different health initiatives in these areas. This paper discusses an e-Health service that facilitates dissemination of health information to people living in poor areas and that is subsequently used to generate revenue to support deployment and development of ICT in the areas. The tool was developed within the context of the Siyakhula Living Lab (SLL), a multi-stakeholder operation that promotes ICT for Development in the Eastern Cape Province of South Africa. Creation of health con-tent for the e-health service and its subsequent consumption happen in two different environments from a technological and social point of view. To enable this to happen, the e-service comprises two component applications that run in a peer-to-peer fashion. The component that is used to disseminate content for end-user consumption is called the HealthMessenger. The HealthMessenger is hosted on an environment called TeleWeaver, an application integration platform developed within the SLL to host software applications targeting people living in poor ar-eas. The platform is customised to support services with a revenue generation component.
- Full Text:
- Date Issued: 2016
- Authors: Gremu, Chikumbutso , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430609 , vital:72703 , 10.1109/ISTAFRICA.2016.7530632
- Description: Development and implementation of appropriate e-services as well as revenue generation are key to deploying and sustaining ICT installa-tions in poor areas in developing countries. The area of e-Health is a promising area for e-Services that are important to populations in poor areas and health service organisations that are already spending mon-ey on different health initiatives in these areas. This paper discusses an e-Health service that facilitates dissemination of health information to people living in poor areas and that is subsequently used to generate revenue to support deployment and development of ICT in the areas. The tool was developed within the context of the Siyakhula Living Lab (SLL), a multi-stakeholder operation that promotes ICT for Development in the Eastern Cape Province of South Africa. Creation of health con-tent for the e-health service and its subsequent consumption happen in two different environments from a technological and social point of view. To enable this to happen, the e-service comprises two component applications that run in a peer-to-peer fashion. The component that is used to disseminate content for end-user consumption is called the HealthMessenger. The HealthMessenger is hosted on an environment called TeleWeaver, an application integration platform developed within the SLL to host software applications targeting people living in poor ar-eas. The platform is customised to support services with a revenue generation component.
- Full Text:
- Date Issued: 2016
Heat accumulation and development rate of massed maggots of the sheep blowfly, Lucilia cuprina (Diptera: Calliphoridae)
- Kotzé, Zanthé, Villet, Martin H, Weldon, Christopher W
- Authors: Kotzé, Zanthé , Villet, Martin H , Weldon, Christopher W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442168 , vital:73964 , https://doi.org/10.1016/j.jinsphys.2016.09.009
- Description: Blowfly larvae aggregate on exposed carcasses and corpses and pass through three instars before wandering from the carcass and pupating. The developmental landmarks in this process can be used by forensic entomologists to estimate the time since the insects colonised the carcass, which sets a minimum post mortem interval. Large aggregations of feeding larvae generate a microclimate with temperatures up to 15 °C above ambient conditions, which may accelerate larval development and affect forensic estimates of post-mortem intervals. This study investigated the effects of heat accumulated by maggot masses of Lucilia cuprina at aggregations of 20, 50 and 100 larvae, each at incubation temperatures of 18 °C, 24 °C and 30 °C, using body length and life stage as developmental indicators. Aggregation temperatures reached up to 18.7 °C above ambient temperature, with significant effects of both size and temperature of the aggregation on the development time of its larvae. Survivorship was highest for all life stages at 24 °C, which is near the developmental optimum of L. cuprina. The results of this study provide a broadly applicable method of quantifying heat accumulation by aggregations of a wide range of species of forensic importance, and the results obtained from such studies will demonstrate that ambient temperature cannot be considered the only source of heat that blowfly larvae experience when they develop on a carcass. Neglect of temperatures within larval aggregations will result in an overestimation of post-mortem intervals and thus have far-reaching medicolegal consequences.
- Full Text:
- Date Issued: 2016
- Authors: Kotzé, Zanthé , Villet, Martin H , Weldon, Christopher W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442168 , vital:73964 , https://doi.org/10.1016/j.jinsphys.2016.09.009
- Description: Blowfly larvae aggregate on exposed carcasses and corpses and pass through three instars before wandering from the carcass and pupating. The developmental landmarks in this process can be used by forensic entomologists to estimate the time since the insects colonised the carcass, which sets a minimum post mortem interval. Large aggregations of feeding larvae generate a microclimate with temperatures up to 15 °C above ambient conditions, which may accelerate larval development and affect forensic estimates of post-mortem intervals. This study investigated the effects of heat accumulated by maggot masses of Lucilia cuprina at aggregations of 20, 50 and 100 larvae, each at incubation temperatures of 18 °C, 24 °C and 30 °C, using body length and life stage as developmental indicators. Aggregation temperatures reached up to 18.7 °C above ambient temperature, with significant effects of both size and temperature of the aggregation on the development time of its larvae. Survivorship was highest for all life stages at 24 °C, which is near the developmental optimum of L. cuprina. The results of this study provide a broadly applicable method of quantifying heat accumulation by aggregations of a wide range of species of forensic importance, and the results obtained from such studies will demonstrate that ambient temperature cannot be considered the only source of heat that blowfly larvae experience when they develop on a carcass. Neglect of temperatures within larval aggregations will result in an overestimation of post-mortem intervals and thus have far-reaching medicolegal consequences.
- Full Text:
- Date Issued: 2016
Heterogeneity in virulence relationships between Cryptophlebia leucotreta granulovirus isolates and geographically distinct host populations: Lessons from codling moth resistance to CpGV-M
- Opoku-Debrah, John K, Hill, Martin P, Knox, Caroline M, Moore, Sean D
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417998 , vital:71500 , xlink:href="https://doi.org/10.1007/s10526-016-9728-1"
- Description: In South Africa, the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) is used to control the citrus pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). However, the risk associated with continuous application of a single active ingredient is resistance. In order to manage resistance should it occur in field populations of T. leucotreta in South Africa, five new CrleGV genotypes from geographically distinct insect populations which were shown to exhibit some degree of phenotypic variation were recovered and genetically characterized. In droplet bioassays using seven CrleGV isolates against five T. leucotreta populations, some isolates were found to show higher virulence to some host populations than others. There were marked differences in the LD50 values of isolates and the number of occlusion bodies required per larva ranged between 0.79 and 3.12. The significance of these findings with respect to the application of CrleGV biopesticides and the management of resistance is discussed.
- Full Text:
- Date Issued: 2016
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417998 , vital:71500 , xlink:href="https://doi.org/10.1007/s10526-016-9728-1"
- Description: In South Africa, the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) is used to control the citrus pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). However, the risk associated with continuous application of a single active ingredient is resistance. In order to manage resistance should it occur in field populations of T. leucotreta in South Africa, five new CrleGV genotypes from geographically distinct insect populations which were shown to exhibit some degree of phenotypic variation were recovered and genetically characterized. In droplet bioassays using seven CrleGV isolates against five T. leucotreta populations, some isolates were found to show higher virulence to some host populations than others. There were marked differences in the LD50 values of isolates and the number of occlusion bodies required per larva ranged between 0.79 and 3.12. The significance of these findings with respect to the application of CrleGV biopesticides and the management of resistance is discussed.
- Full Text:
- Date Issued: 2016
Impacts of HIV/AIDS on food consumption and wild food use in rural South Africa
- Ncube, Keitometsi, Shackleton, Charlie M, Swallow, Brent M, Dassanayake, Wijaya
- Authors: Ncube, Keitometsi , Shackleton, Charlie M , Swallow, Brent M , Dassanayake, Wijaya
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180412 , vital:43385 , xlink:href="https://doi.org/10.1007/s12571-016-0624-4"
- Description: HIV/AIDS can affect household food consumption in many ways, including through reductions in availability and quality of labour, reductions in earned income, and increased expenditure on medications. In rural South Africa, these negative effects can be buffered by social safety net programs provided by government and collection of wild foods. Despite some acknowledgement of the potential safety net role of wild foods, however, their contribution relative to other food sources in the context of HIV/AIDS remains underexplored. Here we report empirical findings from two rural communities in the Eastern Cape province of South Africa. Qualitative and quantitative methods were used to characterise food sources, intake and calories from 68 HIV/AIDS afflicted households and 87 non-afflicted households every quarter over 12 months. Results show that diets were moderately well-balanced though limited in variety, with cereal items contributing 52 % to total calorie intake. The bulk of food consumed by households was purchased, with supplementation from own production, collected wild vegetables and collected wild fruits. Up to 20 % of respondents from both HIV/ AIDS afflicted and non-afflicted households had insufficient daily caloric intake. Multivariate analyses show that, all else equal, individuals living in households afflicted by HIV/AIDS consumed fewer calories, had less diverse diets, and were more dependent on wild foods than those living in non-afflicted households. Given the detrimental effects of HIV/AIDS on income and home production, wild foods represent a free and readily available food source for vulnerable households.
- Full Text:
- Date Issued: 2016
- Authors: Ncube, Keitometsi , Shackleton, Charlie M , Swallow, Brent M , Dassanayake, Wijaya
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180412 , vital:43385 , xlink:href="https://doi.org/10.1007/s12571-016-0624-4"
- Description: HIV/AIDS can affect household food consumption in many ways, including through reductions in availability and quality of labour, reductions in earned income, and increased expenditure on medications. In rural South Africa, these negative effects can be buffered by social safety net programs provided by government and collection of wild foods. Despite some acknowledgement of the potential safety net role of wild foods, however, their contribution relative to other food sources in the context of HIV/AIDS remains underexplored. Here we report empirical findings from two rural communities in the Eastern Cape province of South Africa. Qualitative and quantitative methods were used to characterise food sources, intake and calories from 68 HIV/AIDS afflicted households and 87 non-afflicted households every quarter over 12 months. Results show that diets were moderately well-balanced though limited in variety, with cereal items contributing 52 % to total calorie intake. The bulk of food consumed by households was purchased, with supplementation from own production, collected wild vegetables and collected wild fruits. Up to 20 % of respondents from both HIV/ AIDS afflicted and non-afflicted households had insufficient daily caloric intake. Multivariate analyses show that, all else equal, individuals living in households afflicted by HIV/AIDS consumed fewer calories, had less diverse diets, and were more dependent on wild foods than those living in non-afflicted households. Given the detrimental effects of HIV/AIDS on income and home production, wild foods represent a free and readily available food source for vulnerable households.
- Full Text:
- Date Issued: 2016
Improvement of nonlinear optical properties of phthalocyanine bearing diethyleneglycole chains
- Britton, Jonathan, Martynov, Alexander G, Oluwole, David O, Gorbunova, Yulia G, Tsivadze, Yulia G, Nyokong, Tebello
- Authors: Britton, Jonathan , Martynov, Alexander G , Oluwole, David O , Gorbunova, Yulia G , Tsivadze, Yulia G , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239812 , vital:50769 , xlink:href="https://doi.org/10.1142/S1088424616501042"
- Description: This paper reports the successful synthesis of the low symmetry phthalocyanines: metal-free 2,3-bis[2′-(2′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxyphthalocyanine 1H22 and its zinc complex 1Zn along with their nonlinear optical (NLO) behavior in solution and in thin films. 1H NMR investigations evidenced of higher dissymmetry of electronic density in 1H22 in comparison with 1Zn. This dissymmetry is responsible for unusually higher values of Im[χ(3)χ(3)]/αα, βeffβeff, and γγ for 1H22in contrast to 1Zn, where the notable effect of heavy-metal enhancement of ISC was expected. Both compounds showed Im[χ(3)χ(3)]/αα values of the order of 10−11−11 in chloroform which are higher in comparison to the symmetrical octabutoxyphthalocyanine H2[(BuO)8Pc]. NLO properties of 1H22 were improved via its incorporation into polycarbonate polymeric matrix together with CdSe@CdS-TOPO quantum dots. In such composite the value of Im[χ(3)χ(3)]/αα was almost three times higher in comparison with 1H22 solution in chloroform. The obtained composites are expected to be perspective components of optical materials, capable of protection against strong light irradiation
- Full Text:
- Date Issued: 2016
- Authors: Britton, Jonathan , Martynov, Alexander G , Oluwole, David O , Gorbunova, Yulia G , Tsivadze, Yulia G , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239812 , vital:50769 , xlink:href="https://doi.org/10.1142/S1088424616501042"
- Description: This paper reports the successful synthesis of the low symmetry phthalocyanines: metal-free 2,3-bis[2′-(2′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxyphthalocyanine 1H22 and its zinc complex 1Zn along with their nonlinear optical (NLO) behavior in solution and in thin films. 1H NMR investigations evidenced of higher dissymmetry of electronic density in 1H22 in comparison with 1Zn. This dissymmetry is responsible for unusually higher values of Im[χ(3)χ(3)]/αα, βeffβeff, and γγ for 1H22in contrast to 1Zn, where the notable effect of heavy-metal enhancement of ISC was expected. Both compounds showed Im[χ(3)χ(3)]/αα values of the order of 10−11−11 in chloroform which are higher in comparison to the symmetrical octabutoxyphthalocyanine H2[(BuO)8Pc]. NLO properties of 1H22 were improved via its incorporation into polycarbonate polymeric matrix together with CdSe@CdS-TOPO quantum dots. In such composite the value of Im[χ(3)χ(3)]/αα was almost three times higher in comparison with 1H22 solution in chloroform. The obtained composites are expected to be perspective components of optical materials, capable of protection against strong light irradiation
- Full Text:
- Date Issued: 2016
Incorporation of environmental issues in South Africa’s municipal Integrated Development Plans
- Ruwanza, Sheunesu, Shackleton, Charlie M
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180481 , vital:43393 , xlink:href="https://doi.org/10.1080/13504509.2015.1062161"
- Description: The transition to full democracy in South Africa in 1994 saw local government becoming the focal point for dealing with socio-economic development needs of communities. The Integrated Development Plan (IDP) has been used as the tool for guiding local development objectives, balanced against environmental demands within a sustainable development paradigm. Here we examine the extent to which this is being achieved through an analysis of IDPs from 35 different municipalities at three scales. We test the hypothesis that the metropolitan municipalities are better at mainstreaming environmental issues into their IDPs than local and district municipalities. Results indicate that mainstreaming environmental issues in IDPs is still low. The hypothesis that metropoles are better at mainstreaming environmental issues than district and local municipalities was not accepted since there were no significant differences between municipalities. There was low relative budget allocations and inclusion of vision and mission statements that mainstream environmental issues in all municipalities. For mainstreaming of environmental issues to be effective in IDPs, both proactive approaches and multi-faceted bottom-up and top-down approaches are suggested.
- Full Text:
- Date Issued: 2016
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180481 , vital:43393 , xlink:href="https://doi.org/10.1080/13504509.2015.1062161"
- Description: The transition to full democracy in South Africa in 1994 saw local government becoming the focal point for dealing with socio-economic development needs of communities. The Integrated Development Plan (IDP) has been used as the tool for guiding local development objectives, balanced against environmental demands within a sustainable development paradigm. Here we examine the extent to which this is being achieved through an analysis of IDPs from 35 different municipalities at three scales. We test the hypothesis that the metropolitan municipalities are better at mainstreaming environmental issues into their IDPs than local and district municipalities. Results indicate that mainstreaming environmental issues in IDPs is still low. The hypothesis that metropoles are better at mainstreaming environmental issues than district and local municipalities was not accepted since there were no significant differences between municipalities. There was low relative budget allocations and inclusion of vision and mission statements that mainstream environmental issues in all municipalities. For mainstreaming of environmental issues to be effective in IDPs, both proactive approaches and multi-faceted bottom-up and top-down approaches are suggested.
- Full Text:
- Date Issued: 2016
Interaction of graphene quantum dots with 4-acetamido-2, 2, 6, 6-tetramethylpiperidine-oxyl free radicals
- Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189031 , vital:44810 , xlink:href="https://doi.org/10.1007/s10895-015-1712-0"
- Description: We report on the interaction of graphene quantum dots (GQDs) with 4-acetamido-2,2,6,6-tetramethylpiperidineoxyl (4-acetamido-TEMPO) free radicals. The GQDs were N and S, N doped. The fluorescence quantum yields were higher for the doped GQDs compared to the undoped. The interaction is assessed by spectrofluorimetric, steady state/time resolved fluorescence and electron paramagnetic resonance (EPR) techniques. Fluorescence quenching was observed upon the addition of 4-acetamido-TEMPO to the GQDs. Photoinduced electron transfer (PET) mechanism was suggested as the plausible mechanism involved in the fluorescence quenching in which 4-acetamido-TEMPO acted as the electron acceptor.
- Full Text:
- Date Issued: 2016
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189031 , vital:44810 , xlink:href="https://doi.org/10.1007/s10895-015-1712-0"
- Description: We report on the interaction of graphene quantum dots (GQDs) with 4-acetamido-2,2,6,6-tetramethylpiperidineoxyl (4-acetamido-TEMPO) free radicals. The GQDs were N and S, N doped. The fluorescence quantum yields were higher for the doped GQDs compared to the undoped. The interaction is assessed by spectrofluorimetric, steady state/time resolved fluorescence and electron paramagnetic resonance (EPR) techniques. Fluorescence quenching was observed upon the addition of 4-acetamido-TEMPO to the GQDs. Photoinduced electron transfer (PET) mechanism was suggested as the plausible mechanism involved in the fluorescence quenching in which 4-acetamido-TEMPO acted as the electron acceptor.
- Full Text:
- Date Issued: 2016
Investigating multi-thread utilization as a software defence mechanism against side channel attacks
- Frieslaar, Ibraheem, Irwin, Barry V W
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430190 , vital:72672 , https://doi.org/10.1145/3015166.3015176
- Description: A state-of-the-art software countermeasure to defend against side channel attacks is investigated in this work. The implementation of this novel approach consists of using multi-threads and a task scheduler on a microcontroller to purposefully leak out information at critical points in the cryptographic algorithm and confuse the attacker. This research demonstrates it is capable of outperforming the known countermeasure of hiding and shuffling in terms of preventing the secret information from being leaked out. Furthermore, the proposed countermeasure mitigates the side channel attacks, such as correlation power analysis and template attacks.
- Full Text:
- Date Issued: 2016
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430190 , vital:72672 , https://doi.org/10.1145/3015166.3015176
- Description: A state-of-the-art software countermeasure to defend against side channel attacks is investigated in this work. The implementation of this novel approach consists of using multi-threads and a task scheduler on a microcontroller to purposefully leak out information at critical points in the cryptographic algorithm and confuse the attacker. This research demonstrates it is capable of outperforming the known countermeasure of hiding and shuffling in terms of preventing the secret information from being leaked out. Furthermore, the proposed countermeasure mitigates the side channel attacks, such as correlation power analysis and template attacks.
- Full Text:
- Date Issued: 2016