Genetic and biological characterisation of a novel Plutella xylostella granulovirus, PlxyGV-SA
- Abdulkadir, Fatima, Knox, Caroline M, Marsberg, Tamryn, Hill, Martin P, Moore, Sean D
- Authors: Abdulkadir, Fatima , Knox, Caroline M , Marsberg, Tamryn , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417971 , vital:71498 , xlink:href="https://doi.org/10.1007/s10526-015-9666-3"
- Description: Plutella xylostella granulovirus (PlxyGV) has been isolated from insect populations in many countries and is considered a potential biopesticide for sustainable control of P. xylostella (L.) (Lepidoptera: Plutellidae). Several PlxyGV isolates have been genetically characterised, and the full genome sequence of PlxyGV-Japan is available for comparison with novel isolates. A South African PlxyGV was recently recovered from an overcrowded laboratory P. xylostella colony and identified as a genetically distinct isolate by sequencing of the granulin gene and restriction endonuclease (REN) analysis of genomic DNA. In this report, PlxyGV-SA was further characterised by PCR amplification and sequencing of egt, lef-8 and lef-9 genes, and several amino acid substitutions were observed. The PstI REN profile of PlxyGV-SA was different from that of PlxyGV-Japan in terms of band size and number, thereby confirming its novel genetic identity. Surface dose bioassays showed that PlxyGV-SA is pathogenic to neonate but not late instar larvae at the same and higher virus doses, indicating that a biopesticide should be targeted at early larval stages in the field.
- Full Text:
- Date Issued: 2015
- Authors: Abdulkadir, Fatima , Knox, Caroline M , Marsberg, Tamryn , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417971 , vital:71498 , xlink:href="https://doi.org/10.1007/s10526-015-9666-3"
- Description: Plutella xylostella granulovirus (PlxyGV) has been isolated from insect populations in many countries and is considered a potential biopesticide for sustainable control of P. xylostella (L.) (Lepidoptera: Plutellidae). Several PlxyGV isolates have been genetically characterised, and the full genome sequence of PlxyGV-Japan is available for comparison with novel isolates. A South African PlxyGV was recently recovered from an overcrowded laboratory P. xylostella colony and identified as a genetically distinct isolate by sequencing of the granulin gene and restriction endonuclease (REN) analysis of genomic DNA. In this report, PlxyGV-SA was further characterised by PCR amplification and sequencing of egt, lef-8 and lef-9 genes, and several amino acid substitutions were observed. The PstI REN profile of PlxyGV-SA was different from that of PlxyGV-Japan in terms of band size and number, thereby confirming its novel genetic identity. Surface dose bioassays showed that PlxyGV-SA is pathogenic to neonate but not late instar larvae at the same and higher virus doses, indicating that a biopesticide should be targeted at early larval stages in the field.
- Full Text:
- Date Issued: 2015
Optical properties of water-soluble L-cysteine-capped alloyed CdSeS quantum dot passivated with ZnSeTe and ZnSeTe/ZnS shells
- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B C
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193609 , vital:45352 , xlink:href="https://doi.org/10.1016/j.optmat.2015.05.024"
- Description: Alloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing L-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed L-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties.
- Full Text:
- Date Issued: 2015
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193609 , vital:45352 , xlink:href="https://doi.org/10.1016/j.optmat.2015.05.024"
- Description: Alloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing L-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed L-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties.
- Full Text:
- Date Issued: 2015
Structural and optical properties of alloyed quaternary CdSeTeS core and CdSeTeS/ZnS core–shell quantum dots
- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B C
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193575 , vital:45349 , xlink:href="https://doi.org/10.1016/j.jallcom.2015.05.083"
- Description: Synthesis of fluorescent alloyed quantum dots (QDs) with unique optical properties suitable for a wide array of chemical, physical and biological applications is of research interest. In this work, highly luminescent and photostable alloyed quaternary CdSeTeS core QDs of two different sizes were fabricated via the organometallic hot-injection synthetic route. Characterization of the nanocrystals were performed using TEM, XRD, UV/vis and fluorescence spectrophotometric techniques. We have demonstrated in this work that the well fabricated alloyed quaternary CdSeTeS core QDs possess unique optical properties that are advantageous over conventional core/shell systems. Formation of the CdSeTeS/ZnS core/shell with the desired optical properties comes with a number of challenges, hence the advantages of the quaternary alloyed core over the core/shell QDs are (i) avoidance of the challenging process of determining the proper shell thickness which can provide the desired optical properties in the core/shell system and (ii) avoidance of the lattice-induced mismatch between the core and the shell material which can either lead to incomplete exciton confinement or dislocation at the core/shell interface.
- Full Text:
- Date Issued: 2015
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193575 , vital:45349 , xlink:href="https://doi.org/10.1016/j.jallcom.2015.05.083"
- Description: Synthesis of fluorescent alloyed quantum dots (QDs) with unique optical properties suitable for a wide array of chemical, physical and biological applications is of research interest. In this work, highly luminescent and photostable alloyed quaternary CdSeTeS core QDs of two different sizes were fabricated via the organometallic hot-injection synthetic route. Characterization of the nanocrystals were performed using TEM, XRD, UV/vis and fluorescence spectrophotometric techniques. We have demonstrated in this work that the well fabricated alloyed quaternary CdSeTeS core QDs possess unique optical properties that are advantageous over conventional core/shell systems. Formation of the CdSeTeS/ZnS core/shell with the desired optical properties comes with a number of challenges, hence the advantages of the quaternary alloyed core over the core/shell QDs are (i) avoidance of the challenging process of determining the proper shell thickness which can provide the desired optical properties in the core/shell system and (ii) avoidance of the lattice-induced mismatch between the core and the shell material which can either lead to incomplete exciton confinement or dislocation at the core/shell interface.
- Full Text:
- Date Issued: 2015
Food on the Table: Human Responses and Changing Coastal Fisheries in Solomon Islands
- Albert, Simon, Aswani, Shankar, Fisher, Paul L, Albert, Joelle
- Authors: Albert, Simon , Aswani, Shankar , Fisher, Paul L , Albert, Joelle
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421887 , vital:71893 , xlink:href="https://doi.org/10.1371/journal.pone.0130800"
- Description: Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future.
- Full Text:
- Date Issued: 2015
- Authors: Albert, Simon , Aswani, Shankar , Fisher, Paul L , Albert, Joelle
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421887 , vital:71893 , xlink:href="https://doi.org/10.1371/journal.pone.0130800"
- Description: Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future.
- Full Text:
- Date Issued: 2015
Standard Practices
- Amendt, Jens, Anderson, G, Campobasso, Carlo P, Dadour, I R, Gaudry, E, Hall, Martin J R, Moretti, T C, Sukontason, K L, Villet, Martin H
- Authors: Amendt, Jens , Anderson, G , Campobasso, Carlo P , Dadour, I R , Gaudry, E , Hall, Martin J R , Moretti, T C , Sukontason, K L , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442821 , vital:74036 , ISBN , https://www.routledge.com/Forensic-Entomology-International-Dimensions-and-Frontiers/Tomberlin-Benbow/p/book/9780367575885
- Description: The use of forensic entomology has become established as a global science. Recent efforts in the field bridge multiple disciplines including, but not limited to, microbiology, chemistry, genetics, and systematics as well as ecology and evolution. The first book of its kind, Forensic Entomology: International Dimensions and Frontiers provides an inclusive summary of worldwide research on this body of knowledge that integrates aspects of a wide range of scientific realms. The book first reviews the history of forensic entomology, its accomplishments, and future challenges in nations around the world. It then provides perspectives of other scientific disciplines that are shaping the questions being addressed in the field.
- Full Text:
- Date Issued: 2015
- Authors: Amendt, Jens , Anderson, G , Campobasso, Carlo P , Dadour, I R , Gaudry, E , Hall, Martin J R , Moretti, T C , Sukontason, K L , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442821 , vital:74036 , ISBN , https://www.routledge.com/Forensic-Entomology-International-Dimensions-and-Frontiers/Tomberlin-Benbow/p/book/9780367575885
- Description: The use of forensic entomology has become established as a global science. Recent efforts in the field bridge multiple disciplines including, but not limited to, microbiology, chemistry, genetics, and systematics as well as ecology and evolution. The first book of its kind, Forensic Entomology: International Dimensions and Frontiers provides an inclusive summary of worldwide research on this body of knowledge that integrates aspects of a wide range of scientific realms. The book first reviews the history of forensic entomology, its accomplishments, and future challenges in nations around the world. It then provides perspectives of other scientific disciplines that are shaping the questions being addressed in the field.
- Full Text:
- Date Issued: 2015
The Cohen and Kuttel stories: is the place where I hang my hat still relevant to determine my residence for tax purposes?
- Arendse, Jacqueline A, Stark, Karen, Renaud, Craig
- Authors: Arendse, Jacqueline A , Stark, Karen , Renaud, Craig
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131285 , vital:36549 , DOI: 10.25159/1998-8125/5779
- Description: Determining the residence of a taxpayer is one of the most important aspects of modern tax systems. For an individual taxpayer who migrates, a common trend in the modern world, the questions are where the person is ordinarily resident and whether the place of ordinary residence can change.
- Full Text:
- Date Issued: 2015
- Authors: Arendse, Jacqueline A , Stark, Karen , Renaud, Craig
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131285 , vital:36549 , DOI: 10.25159/1998-8125/5779
- Description: Determining the residence of a taxpayer is one of the most important aspects of modern tax systems. For an individual taxpayer who migrates, a common trend in the modern world, the questions are where the person is ordinarily resident and whether the place of ordinary residence can change.
- Full Text:
- Date Issued: 2015
Synthesis and characterization of ZnO nanoparticle synthesized by a microwave-assisted combustion method and catalytic activity for the removal of ortho-nitrophenol
- Assi, Navid, Mohammadi, Ali, Sadr Manuchehri, Q, Walker, Roderick B
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
Global Cicada Sound Collection I: Recordings from South Africa and Malawi by BW Price and MH Villet and harvesting of BioAcoustica data by GBIF
- Baker, Ed, Price, Benjamin W, Rycroft, Simon, Villet, Martin H
- Authors: Baker, Ed , Price, Benjamin W , Rycroft, Simon , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441420 , vital:73886 , https://bdj.pensoft.net/articles.php?id=5792
- Description: Sound collections for singing insects provide important repositories that underpin existing research (eg Price et al. 2007 at http://bio. acousti. ca/node/11801; Price et al. 2010) and make bioacoustic collections available for future work, including insect communication (Ordish 1992), systematics (eg David et al. 2003), and automated identification (Bennett et al. 2015). The BioAcoustica platform (Baker et al. 2015) is both a repository and analysis platform for bioacoustic collections: allowing collections to be available in perpetuity, and also facilitating complex analyses using the BioVeL cloud infrastructure (Vicario et al. 2011). The Global Cicada Sound Collection is a project to make recordings of the world's cicadas (Hemiptera: Cicadidae) available using open licences to maximise their potential for study and reuse. This first component of the Global Cicada Sound Collection comprises recordings made between 2006 and 2008 of Cicadidae in South Africa and Malawi.
- Full Text:
- Date Issued: 2015
- Authors: Baker, Ed , Price, Benjamin W , Rycroft, Simon , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441420 , vital:73886 , https://bdj.pensoft.net/articles.php?id=5792
- Description: Sound collections for singing insects provide important repositories that underpin existing research (eg Price et al. 2007 at http://bio. acousti. ca/node/11801; Price et al. 2010) and make bioacoustic collections available for future work, including insect communication (Ordish 1992), systematics (eg David et al. 2003), and automated identification (Bennett et al. 2015). The BioAcoustica platform (Baker et al. 2015) is both a repository and analysis platform for bioacoustic collections: allowing collections to be available in perpetuity, and also facilitating complex analyses using the BioVeL cloud infrastructure (Vicario et al. 2011). The Global Cicada Sound Collection is a project to make recordings of the world's cicadas (Hemiptera: Cicadidae) available using open licences to maximise their potential for study and reuse. This first component of the Global Cicada Sound Collection comprises recordings made between 2006 and 2008 of Cicadidae in South Africa and Malawi.
- Full Text:
- Date Issued: 2015
Photophysical and nonlinear optical studies of tetraakynyl zincphthalocyanine and its “clicked” analogue
- Bankole, Owolabi M, Nyokong, Tebello
- Authors: Bankole, Owolabi M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189325 , vital:44837 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.01.048"
- Description: We report here for the first time on the photophysical and nonlinear optical behavior of tetra-substituted alkynyl zinc phthalocyanine and its “clicked” analogue (4 and 5). The compounds exhibited high triplet quantum yields in dimethylsulphoxide (DMSO). Nonlinear optical (NLO) properties were also evaluated for the two compounds at 532 nm and 10 ns in DMSO. We observed two-photon absorption (2PA) and strong reverse saturable absorption (RSA) as the dominant mechanisms at nanosecond laser excitation. The presence of electron acceptor groups fused with triazole linkers in the peripheral positions of 4 provide excellent coexistent features, such as enhanced triplet quantum yields and lifetimes compared to 5. Large third-order susceptibility (2.09 × 10−11 and 3.53 × 10−9 esu) and hyperpolarizability (1.09 × 10−30 and 9.13 × 10−29 esu) were estimated for complexs 4 and 5, respectively.
- Full Text:
- Date Issued: 2015
- Authors: Bankole, Owolabi M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189325 , vital:44837 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.01.048"
- Description: We report here for the first time on the photophysical and nonlinear optical behavior of tetra-substituted alkynyl zinc phthalocyanine and its “clicked” analogue (4 and 5). The compounds exhibited high triplet quantum yields in dimethylsulphoxide (DMSO). Nonlinear optical (NLO) properties were also evaluated for the two compounds at 532 nm and 10 ns in DMSO. We observed two-photon absorption (2PA) and strong reverse saturable absorption (RSA) as the dominant mechanisms at nanosecond laser excitation. The presence of electron acceptor groups fused with triazole linkers in the peripheral positions of 4 provide excellent coexistent features, such as enhanced triplet quantum yields and lifetimes compared to 5. Large third-order susceptibility (2.09 × 10−11 and 3.53 × 10−9 esu) and hyperpolarizability (1.09 × 10−30 and 9.13 × 10−29 esu) were estimated for complexs 4 and 5, respectively.
- Full Text:
- Date Issued: 2015
Rapid bioassessment of the effects of repeated rotenone treatments on invertebrate assemblages in the Rondegat River, South Africa
- Bellingan, Terence A, Woodford, Darragh J, Gouws, Jeanne, Villet, Martin H, Weyl, Olaf L F
- Authors: Bellingan, Terence A , Woodford, Darragh J , Gouws, Jeanne , Villet, Martin H , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442279 , vital:73972 , https://doi.org/10.2989/16085914.2014.984651
- Description: The potential collateral effects of eradicating invasive fishes in streams necessitate the monitoring of invertebrate communities during treatment. In an environmental rehabilitation programme, non-native smallmouth bass were removed from the lower reaches of the Rondegat River, Western Cape, South Africa, in 2012 and again in 2013 using the piscicide rotenone. A monitoring programme tracked the ecological response of organisms to these activities using quantitative sampling of macroinvertebrates on stones and the ISO-certified SASS5 rapid bioassessment method for assessing macroinvertebrate community integrity. We recorded a significant decrease in macroinvertebrate densities from the stones-in-current biotope following both rotenone treatments. The average score per taxon (ASPT) declined after the first treatment, indicating a loss of taxa sensitive to diminished water quality, then recovered prior to the second treatment, and subsequently no decline was detected after the lower dose used in the 2013 treatment. The SASS values were too variable to reveal trends. The ASPTs indicated that the community may have been resistant to low dose and resilient to high dose, due to inter-treatment recovery following the 2012 treatment, suggesting that the invertebrate assemblage is resilient to the conservative use of rotenone for localised river rehabilitation when upstream sources of recruitment exist.
- Full Text:
- Date Issued: 2015
- Authors: Bellingan, Terence A , Woodford, Darragh J , Gouws, Jeanne , Villet, Martin H , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442279 , vital:73972 , https://doi.org/10.2989/16085914.2014.984651
- Description: The potential collateral effects of eradicating invasive fishes in streams necessitate the monitoring of invertebrate communities during treatment. In an environmental rehabilitation programme, non-native smallmouth bass were removed from the lower reaches of the Rondegat River, Western Cape, South Africa, in 2012 and again in 2013 using the piscicide rotenone. A monitoring programme tracked the ecological response of organisms to these activities using quantitative sampling of macroinvertebrates on stones and the ISO-certified SASS5 rapid bioassessment method for assessing macroinvertebrate community integrity. We recorded a significant decrease in macroinvertebrate densities from the stones-in-current biotope following both rotenone treatments. The average score per taxon (ASPT) declined after the first treatment, indicating a loss of taxa sensitive to diminished water quality, then recovered prior to the second treatment, and subsequently no decline was detected after the lower dose used in the 2013 treatment. The SASS values were too variable to reveal trends. The ASPTs indicated that the community may have been resistant to low dose and resilient to high dose, due to inter-treatment recovery following the 2012 treatment, suggesting that the invertebrate assemblage is resilient to the conservative use of rotenone for localised river rehabilitation when upstream sources of recruitment exist.
- Full Text:
- Date Issued: 2015
Specific rewards for tax compliance: responses of small business owners in Ekurhuleni, South Africa
- Bornman, Marina, Stack, Elizabeth M
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145325 , vital:38428 , https://heinonline.org/HOL/Page?handle=hein.journals/ejotaxrs13anddiv=35andg_sent=1andcasa_token=andcollection=journals
- Description: The literature reviewed documents the positive effects of rewards in encouraging desired behaviour, but rewards may have a crowding-in effect, strengthening intrinsic motivation, or a crowding-out effect, weakening it. External interventions may therefore be perceived as supportive, fostering self-esteem and self-determination, while those perceived as controlling may have the opposite effect. A number of countries have adopted a strategy of rewarding tax compliance. The rewards range from certificates awarded to compliant taxpayers, to privilege cards providing opportunities for discounts or special treatment, to lotteries in which compliant taxpayers can participate. The reward strategies are often accompanied by publicity programmes. Two such hypothetical strategies were presented to participants in a survey conducted amongst small business owners in Ekurhuleni, South Africa, to gauge their responses.
- Full Text:
- Date Issued: 2015
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145325 , vital:38428 , https://heinonline.org/HOL/Page?handle=hein.journals/ejotaxrs13anddiv=35andg_sent=1andcasa_token=andcollection=journals
- Description: The literature reviewed documents the positive effects of rewards in encouraging desired behaviour, but rewards may have a crowding-in effect, strengthening intrinsic motivation, or a crowding-out effect, weakening it. External interventions may therefore be perceived as supportive, fostering self-esteem and self-determination, while those perceived as controlling may have the opposite effect. A number of countries have adopted a strategy of rewarding tax compliance. The rewards range from certificates awarded to compliant taxpayers, to privilege cards providing opportunities for discounts or special treatment, to lotteries in which compliant taxpayers can participate. The reward strategies are often accompanied by publicity programmes. Two such hypothetical strategies were presented to participants in a survey conducted amongst small business owners in Ekurhuleni, South Africa, to gauge their responses.
- Full Text:
- Date Issued: 2015
Rewarding tax compliance: taxpayers’ attitudes and beliefs
- Bornman, Marina, Stack, Elizabeth M
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61039 , vital:27931
- Description: In a society the tax climate is determined by the interaction between taxpayers and tax authorities. In a ‘service and client’ climate, taxpayers do not expect authorities to automatically suspect them of being tax evaders. Evidence suggests that recognising good tax behaviour with strategies of rewards has a positive effect on voluntary tax compliance. Principles derived from the cognitive evaluation theory predict that when feelings of competence are affirmed and this is accompanied by a sense of autonomy it can enhance the intrinsic motivation for an action. The present research surveyed the attitudes and beliefs of taxpayers involved in small business on being rewarded for tax compliance. Results were corroborated with the principles of the cognitive evaluation theory and it was found that that the principles of the theory are applicable to rewarding tax compliance behaviour.
- Full Text:
- Date Issued: 2015
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61039 , vital:27931
- Description: In a society the tax climate is determined by the interaction between taxpayers and tax authorities. In a ‘service and client’ climate, taxpayers do not expect authorities to automatically suspect them of being tax evaders. Evidence suggests that recognising good tax behaviour with strategies of rewards has a positive effect on voluntary tax compliance. Principles derived from the cognitive evaluation theory predict that when feelings of competence are affirmed and this is accompanied by a sense of autonomy it can enhance the intrinsic motivation for an action. The present research surveyed the attitudes and beliefs of taxpayers involved in small business on being rewarded for tax compliance. Results were corroborated with the principles of the cognitive evaluation theory and it was found that that the principles of the theory are applicable to rewarding tax compliance behaviour.
- Full Text:
- Date Issued: 2015
Bhaskar and collective action: Using laminations to structure a literature review of collective action and water management
- Authors: Burt, Jane C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436978 , vital:73321 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.
- Full Text:
- Date Issued: 2015
- Authors: Burt, Jane C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436978 , vital:73321 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.
- Full Text:
- Date Issued: 2015
Deep genetic divergence between geographically isolated populations of the goldie barb (Barbus pallidus) in South Africa: potential taxonomic and conservation implications
- Chakona, Albert, Malherbe, Willem S, Gouws, Gavin, Swartz, Ernst R
- Authors: Chakona, Albert , Malherbe, Willem S , Gouws, Gavin , Swartz, Ernst R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443284 , vital:74105 , https://hdl.handle.net/10520/EJC177698
- Description: Barbus pallidus as it is presently defined has a disjunct distribution that is divided between northern and southern populations in South Africa. Sequence data from the cytochrome b gene region showed two distinct lineages that correspond to these geographically distant areas. Divergence between these two lineages was relatively high (5.5-6.5%) and comparable to typical interspecific divergences found between closely related southern African cyprinid fishes. Based on this deep genetic divergence, we conclude that the northern lineage may represent a previously unrecognised species or may belong to a different, but known species or species complex not associated with 'true' B. pallidus. These findings add to a growing body of evidence that freshwater fish diversity in southern Africa requires major revision.
- Full Text:
- Date Issued: 2015
- Authors: Chakona, Albert , Malherbe, Willem S , Gouws, Gavin , Swartz, Ernst R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443284 , vital:74105 , https://hdl.handle.net/10520/EJC177698
- Description: Barbus pallidus as it is presently defined has a disjunct distribution that is divided between northern and southern populations in South Africa. Sequence data from the cytochrome b gene region showed two distinct lineages that correspond to these geographically distant areas. Divergence between these two lineages was relatively high (5.5-6.5%) and comparable to typical interspecific divergences found between closely related southern African cyprinid fishes. Based on this deep genetic divergence, we conclude that the northern lineage may represent a previously unrecognised species or may belong to a different, but known species or species complex not associated with 'true' B. pallidus. These findings add to a growing body of evidence that freshwater fish diversity in southern Africa requires major revision.
- Full Text:
- Date Issued: 2015
The prevalence of planning and management frameworks for trees and green spaces in urban areas of South Africa
- Chishaleshale, M, Shackleton, Charlie M, Gambiza, James, Gumbo, Davison
- Authors: Chishaleshale, M , Shackleton, Charlie M , Gambiza, James , Gumbo, Davison
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180884 , vital:43659 , xlink:href="https://doi.org/10.1016/j.ufug.2015.09.012"
- Description: Optimisation of the benefits from urban forestry and greening to urban dwellers and the environment rests on proactive and appropriate management planning, implementation and resourcing. Yet, lessons from the developed world show marked variability in development and adoption of urban tree and green space (UTGS) strategic plans and systematic monitoring and maintenance. Although financial and human resources for UTGS may be constrained in developing world contexts, there is no knowledge of the extent to which local authorities engage in appropriate and timely planning, management and monitoring. Here we examine the UTGS resourcing, planning, maintenance and integration across 28 local municipalities in the two poorest provinces in South Africa. It was revealed that most local municipalities were not managing their UTGS in a planned or systematic manner due to constraining factors such as insufficient funds, insufficient personnel, lack of equipment and lack of political support. Only 7% of the surveyed municipalities had an urban tree management plan and an estimate of the urban tree stock; 32% had tree policies; 21% had tree planting schedules; 11% had tree maintenance schedules. Over 65% claimed to engage other stakeholders in tree planting, but much was passive receipt of trees for planting rather than citizen engagement around species, places and values. Generally, the prevalence of most planning and maintenance elements increased with increasing size of the municipality and the presence of personnel specifically for UTGS management. It is likely that the prevalence of planning and maintenance functions will increase with greater political support from municipal councillors which may also decrease funding challenges.
- Full Text:
- Date Issued: 2015
- Authors: Chishaleshale, M , Shackleton, Charlie M , Gambiza, James , Gumbo, Davison
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180884 , vital:43659 , xlink:href="https://doi.org/10.1016/j.ufug.2015.09.012"
- Description: Optimisation of the benefits from urban forestry and greening to urban dwellers and the environment rests on proactive and appropriate management planning, implementation and resourcing. Yet, lessons from the developed world show marked variability in development and adoption of urban tree and green space (UTGS) strategic plans and systematic monitoring and maintenance. Although financial and human resources for UTGS may be constrained in developing world contexts, there is no knowledge of the extent to which local authorities engage in appropriate and timely planning, management and monitoring. Here we examine the UTGS resourcing, planning, maintenance and integration across 28 local municipalities in the two poorest provinces in South Africa. It was revealed that most local municipalities were not managing their UTGS in a planned or systematic manner due to constraining factors such as insufficient funds, insufficient personnel, lack of equipment and lack of political support. Only 7% of the surveyed municipalities had an urban tree management plan and an estimate of the urban tree stock; 32% had tree policies; 21% had tree planting schedules; 11% had tree maintenance schedules. Over 65% claimed to engage other stakeholders in tree planting, but much was passive receipt of trees for planting rather than citizen engagement around species, places and values. Generally, the prevalence of most planning and maintenance elements increased with increasing size of the municipality and the presence of personnel specifically for UTGS management. It is likely that the prevalence of planning and maintenance functions will increase with greater political support from municipal councillors which may also decrease funding challenges.
- Full Text:
- Date Issued: 2015
The subspecies of Antarctic Terns (Sterna vittata) wintering on the South African coast: evidence from morphology, genetics and stable isotopes
- Connan, Maëlle, Teske, Peter R, Tree, Anthony J, Whittington, Philip A, McQuaid, Christopher D
- Authors: Connan, Maëlle , Teske, Peter R , Tree, Anthony J , Whittington, Philip A , McQuaid, Christopher D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444854 , vital:74303 , https://doi.org/10.1071/MU14089
- Description: Five to seven subspecies of Antarctic Tern (Sterna vittata) are recognised, with at least three (S. v. vittata, S. v. tristanensis and S. v. sanctipauli) wintering in South Africa. Morphological characters used to define these subspecies are not perfectly reliable, but fidelity to nesting site suggests they could be genetically distinct. We used morphological data and DNA to investigate the validity of subspecies. We further used stable isotope analysis of feather samples collected from the non-breeding grounds in South Africa to attempt to ascertain the population of origin. Nuclear and mitochondrial DNA sequence data identified two major genetic clades: one mostly comprised individuals partially or completely matching the morphological description of S. v. tristanensis, the other included individuals from S. v. vittata and S. v. sanctipauli. Stable isotope values indicated that juveniles originated from at least three populations. Irrespective of their morphological and genetic characteristics, most immatures moulted in Antarctic waters, and adults moulted in various habitats. Their colony of origin could not therefore be inferred from stable isotope values from feathers. Results indicate that morphological groupings may reflect a north-south cline across the Indian Ocean. Adequate conservation strategies require rigorous reassessment of the currently accepted subspecies, including DNA analyses of samples from the breeding grounds, particularly on Amsterdam and St Paul Islands.
- Full Text:
- Date Issued: 2015
- Authors: Connan, Maëlle , Teske, Peter R , Tree, Anthony J , Whittington, Philip A , McQuaid, Christopher D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444854 , vital:74303 , https://doi.org/10.1071/MU14089
- Description: Five to seven subspecies of Antarctic Tern (Sterna vittata) are recognised, with at least three (S. v. vittata, S. v. tristanensis and S. v. sanctipauli) wintering in South Africa. Morphological characters used to define these subspecies are not perfectly reliable, but fidelity to nesting site suggests they could be genetically distinct. We used morphological data and DNA to investigate the validity of subspecies. We further used stable isotope analysis of feather samples collected from the non-breeding grounds in South Africa to attempt to ascertain the population of origin. Nuclear and mitochondrial DNA sequence data identified two major genetic clades: one mostly comprised individuals partially or completely matching the morphological description of S. v. tristanensis, the other included individuals from S. v. vittata and S. v. sanctipauli. Stable isotope values indicated that juveniles originated from at least three populations. Irrespective of their morphological and genetic characteristics, most immatures moulted in Antarctic waters, and adults moulted in various habitats. Their colony of origin could not therefore be inferred from stable isotope values from feathers. Results indicate that morphological groupings may reflect a north-south cline across the Indian Ocean. Adequate conservation strategies require rigorous reassessment of the currently accepted subspecies, including DNA analyses of samples from the breeding grounds, particularly on Amsterdam and St Paul Islands.
- Full Text:
- Date Issued: 2015
Beauveria and Metarhizium against false codling moth (Lepidoptera: Tortricidae): a step towards selecting isolates for potential development of a mycoinsecticide
- Coombes, Candice A, Hill, Martin P, Moore, Sean D, Dames, Joanna F, Fullard, T
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405757 , vital:70203 , xlink:href="https://hdl.handle.net/10520/EJC167505"
- Description: False codling moth, Thaumatotibia leucotreta Meyrick (1912) (Lepidoptera: Tortricidae), can cause both pre- and post-harvest damage to citrus fruit. Not only can this result in reduced crop yield, but more importantly because of the moth's endemism to sub-Saharan Africa, it is classified as a phytosanitary pest by many export markets. An entire consignment of citrus may be rejected in the presence of a single moth (Moore 2012). Since the bulk of citrus fruit production in South Africa is exported, the control of T. leucotreta is critical (Citrus Growers Association, South Africa 2012). Traditionally, control has been achieved through the use of chemical insecticides; however, residue restrictions, resistance development and concerns about environmental pollution have substantially reduced the dependence on chemical pesticides in citrus. Research on T. leucotreta control has therefore focused on the use of biological organisms (e.g. parasitoids and viruses), which are used as control agents within an integrated pest management (IPM) programme in citrus. These biological control agents, however, only targeted the aboveground life stages of the pest, not the soil-dwelling life stages (late fifth instars, prepupae, pupae), which is the subject of this contribution (Moore 2012).
- Full Text:
- Date Issued: 2015
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405757 , vital:70203 , xlink:href="https://hdl.handle.net/10520/EJC167505"
- Description: False codling moth, Thaumatotibia leucotreta Meyrick (1912) (Lepidoptera: Tortricidae), can cause both pre- and post-harvest damage to citrus fruit. Not only can this result in reduced crop yield, but more importantly because of the moth's endemism to sub-Saharan Africa, it is classified as a phytosanitary pest by many export markets. An entire consignment of citrus may be rejected in the presence of a single moth (Moore 2012). Since the bulk of citrus fruit production in South Africa is exported, the control of T. leucotreta is critical (Citrus Growers Association, South Africa 2012). Traditionally, control has been achieved through the use of chemical insecticides; however, residue restrictions, resistance development and concerns about environmental pollution have substantially reduced the dependence on chemical pesticides in citrus. Research on T. leucotreta control has therefore focused on the use of biological organisms (e.g. parasitoids and viruses), which are used as control agents within an integrated pest management (IPM) programme in citrus. These biological control agents, however, only targeted the aboveground life stages of the pest, not the soil-dwelling life stages (late fifth instars, prepupae, pupae), which is the subject of this contribution (Moore 2012).
- Full Text:
- Date Issued: 2015
The timing of moult in males and females of the monomorphic Pale-winged Starling Onychognathus nabouroup
- Craig, Adrian J F K, Bonnevie, Bo T, Hausberger, Martine, Henry, Laurence
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hausberger, Martine , Henry, Laurence
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443805 , vital:74155 , https://hdl.handle.net/10520/EJC177689
- Description: Pale-winged Starlings Onychognathus nabouroup inhabit the arid western interior of southern Africa and moult-breeding overlap may occur. We collected field data in two successive years on the moult of individual birds, whose sex was confirmed by genetic techniques. Small samples revealed a non-significant tendency for the moult of females in the early stages of wing moult to be more advanced than that of males in both years, but also clear evidence that the starting date of moult differed in the two years. In this species the moult schedule may thus be variable at both the individual and the population levels.
- Full Text:
- Date Issued: 2015
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hausberger, Martine , Henry, Laurence
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443805 , vital:74155 , https://hdl.handle.net/10520/EJC177689
- Description: Pale-winged Starlings Onychognathus nabouroup inhabit the arid western interior of southern Africa and moult-breeding overlap may occur. We collected field data in two successive years on the moult of individual birds, whose sex was confirmed by genetic techniques. Small samples revealed a non-significant tendency for the moult of females in the early stages of wing moult to be more advanced than that of males in both years, but also clear evidence that the starting date of moult differed in the two years. In this species the moult schedule may thus be variable at both the individual and the population levels.
- Full Text:
- Date Issued: 2015
The effects of gold coated and uncoated zinc oxide nanohexagons on the photophysicochemical properties of the low symmetry zinc phthalocyanine
- D'Souza, Sarah, Ogbodu, Rachael, Nyokong, Tebello
- Authors: D'Souza, Sarah , Ogbodu, Rachael , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189077 , vital:44814 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.06.088"
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.
- Full Text:
- Date Issued: 2015
- Authors: D'Souza, Sarah , Ogbodu, Rachael , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189077 , vital:44814 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.06.088"
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.
- Full Text:
- Date Issued: 2015
Enhanced triplet state yields in aqueous media of asymmetric zinc phthalocyanines when conjugated to silver nanoflowers
- D'Souza, Sarah, George, Reama, Göksel, Meltem, Atilla, Devrim, Durmus, Mahmut, Nyokong, Tebello
- Authors: D'Souza, Sarah , George, Reama , Göksel, Meltem , Atilla, Devrim , Durmus, Mahmut , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189099 , vital:44816 , xlink:href="https://doi.org/10.1016/j.poly.2015.08.017"
- Description: Novel low symmetry water-soluble zinc phthalocyanines (ZnPcs, complexes 1 and 2) were synthesized and then mixed with silver nanoflowers. Photophysical and photochemical studies were performed in order to determine the efficiency of complexes 1 and 2 as photosensitizers when alone and when combined with the silver nanoflowers. The Pcs show low fluorescence quantum yields and excellent triplet quantum yields of 0.78 (for 1) and 0.66 (for 2) in aqueous media. The triplet quantum yield values increased to 0.80 and 0.89, respectively, in the presence of silver nanoflowers. Long triplet lifetimes ranging from 180 to 200 μs in DMSO were obtained for complexes 1, 2 and their conjugates with silver nanoflowers.
- Full Text:
- Date Issued: 2015
- Authors: D'Souza, Sarah , George, Reama , Göksel, Meltem , Atilla, Devrim , Durmus, Mahmut , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189099 , vital:44816 , xlink:href="https://doi.org/10.1016/j.poly.2015.08.017"
- Description: Novel low symmetry water-soluble zinc phthalocyanines (ZnPcs, complexes 1 and 2) were synthesized and then mixed with silver nanoflowers. Photophysical and photochemical studies were performed in order to determine the efficiency of complexes 1 and 2 as photosensitizers when alone and when combined with the silver nanoflowers. The Pcs show low fluorescence quantum yields and excellent triplet quantum yields of 0.78 (for 1) and 0.66 (for 2) in aqueous media. The triplet quantum yield values increased to 0.80 and 0.89, respectively, in the presence of silver nanoflowers. Long triplet lifetimes ranging from 180 to 200 μs in DMSO were obtained for complexes 1, 2 and their conjugates with silver nanoflowers.
- Full Text:
- Date Issued: 2015