Nonlinear optical behavior of metal octaphenoxy phthalocyanines
- Sanusi, Sikiru O, Antunes, Edith M, Nyokong, Tebello
- Authors: Sanusi, Sikiru O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241717 , vital:50963 , xlink:href="https://doi.org/10.1142/S1088424613500715"
- Description: In this work, we investigated the nonlinear optical absorption properties of chloroaluminum, chlorogallium, chloroindium, zinc and lead octaphenoxy phthalocyanines in a dimethyl sulphoxide solution using 5 ns pulses at 532 nm. Using the Z-scan technique, the nonlinear optical properties and the excited state absorption cross-sections were determined by fitting the Z-scan data. The k value was the highest for Pb derivative at 211, making it the best nonlinear optical material. In terms of hyperpolarizability, Pb derivative (containing a larger central metal) also gave the largest value followed by aluminum derivative (containing a small central metal). The distortion of the ring caused by the central metal is used to explain the hyperpolarizability values. Large nonlinear absorption coefficient values, βeff, in the range of 3.558–4.763 × 10-9 cm.W-1 and low saturation fluence values, Fsat between 21.5–38.5 mJ.cm-2, were obtained for these samples.
- Full Text:
- Authors: Sanusi, Sikiru O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241717 , vital:50963 , xlink:href="https://doi.org/10.1142/S1088424613500715"
- Description: In this work, we investigated the nonlinear optical absorption properties of chloroaluminum, chlorogallium, chloroindium, zinc and lead octaphenoxy phthalocyanines in a dimethyl sulphoxide solution using 5 ns pulses at 532 nm. Using the Z-scan technique, the nonlinear optical properties and the excited state absorption cross-sections were determined by fitting the Z-scan data. The k value was the highest for Pb derivative at 211, making it the best nonlinear optical material. In terms of hyperpolarizability, Pb derivative (containing a larger central metal) also gave the largest value followed by aluminum derivative (containing a small central metal). The distortion of the ring caused by the central metal is used to explain the hyperpolarizability values. Large nonlinear absorption coefficient values, βeff, in the range of 3.558–4.763 × 10-9 cm.W-1 and low saturation fluence values, Fsat between 21.5–38.5 mJ.cm-2, were obtained for these samples.
- Full Text:
Nutrient-mediated effects on Cornops aquaticum Brüner (Orthoptera: Acrididae), a potential biological control agent of water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae)
- Bownes, Angela, Hill, Martin P, Byrne, Marcus J
- Authors: Bownes, Angela , Hill, Martin P , Byrne, Marcus J
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406131 , vital:70241 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.07.023"
- Description: Environmental nutrient availability can drive and modify both plant responses to herbivory by phytophagous insects and insect feeding patterns which, in insect-weed systems, may ultimately determine whether biological control succeeds or fails. The impacts of insect biological control agents on the invasive aquatic weed, water hyacinth (Eichhornia crassipes) vary with nutrient levels in the environment. It was therefore considered important to evaluate nutrient-specific responses of E. crassipes to a grasshopper herbivore, Cornops aquaticum, prior to its release in South Africa. Both plant productivity and the response of E. crassipes to herbivory by C. aquaticum were nutrient dependent. Increases in plant biomass and leaf and ramet production were correlated with increases in nutrients in the water and plant biomass accumulation was reduced by herbivory at all three nutrient levels tested (high = 67%; medium = 100%; low = 400%). C. aquaticum nymphs fed E. crassipes leaves with the lowest nitrogen levels produced the highest biomass of frass during their development, indicating compensatory consumption. The results suggest that environmental nutrient availability will influence efficacy of C. aquaticum. They also provide further evidence that E. crassipes problems are exacerbated by an over-abundance of nutrients in aquatic environments, and that biological control would be a highly effective management tool if aquatic systems in South Africa were less polluted. Additionally, the results also show how an understanding of the fundamental responses of E. crassipes and its insect biocontrol agents to their environment can assist in determining specific management strategies or interventions according to prevailing site-specific conditions.
- Full Text:
- Authors: Bownes, Angela , Hill, Martin P , Byrne, Marcus J
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406131 , vital:70241 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.07.023"
- Description: Environmental nutrient availability can drive and modify both plant responses to herbivory by phytophagous insects and insect feeding patterns which, in insect-weed systems, may ultimately determine whether biological control succeeds or fails. The impacts of insect biological control agents on the invasive aquatic weed, water hyacinth (Eichhornia crassipes) vary with nutrient levels in the environment. It was therefore considered important to evaluate nutrient-specific responses of E. crassipes to a grasshopper herbivore, Cornops aquaticum, prior to its release in South Africa. Both plant productivity and the response of E. crassipes to herbivory by C. aquaticum were nutrient dependent. Increases in plant biomass and leaf and ramet production were correlated with increases in nutrients in the water and plant biomass accumulation was reduced by herbivory at all three nutrient levels tested (high = 67%; medium = 100%; low = 400%). C. aquaticum nymphs fed E. crassipes leaves with the lowest nitrogen levels produced the highest biomass of frass during their development, indicating compensatory consumption. The results suggest that environmental nutrient availability will influence efficacy of C. aquaticum. They also provide further evidence that E. crassipes problems are exacerbated by an over-abundance of nutrients in aquatic environments, and that biological control would be a highly effective management tool if aquatic systems in South Africa were less polluted. Additionally, the results also show how an understanding of the fundamental responses of E. crassipes and its insect biocontrol agents to their environment can assist in determining specific management strategies or interventions according to prevailing site-specific conditions.
- Full Text:
On the trail on Mountain Cicadas, M Gogala: book review
- Authors: Villet, Martin H
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451763 , vital:75075 , https://hdl.handle.net/10520/EJC141289
- Description: Life is about surprises, and if we are lucky they will primarily be welcome. My copy of this book arrived as a happy surprise in the mail, and my delight did not abate until I had finished reading it. I must admit that I have met and like many of the people mentioned in this book, and that I have a special and not unsentimental interest in cicadas, but I think that readers without such background will still find this book fascinating.
- Full Text:
- Authors: Villet, Martin H
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451763 , vital:75075 , https://hdl.handle.net/10520/EJC141289
- Description: Life is about surprises, and if we are lucky they will primarily be welcome. My copy of this book arrived as a happy surprise in the mail, and my delight did not abate until I had finished reading it. I must admit that I have met and like many of the people mentioned in this book, and that I have a special and not unsentimental interest in cicadas, but I think that readers without such background will still find this book fascinating.
- Full Text:
Optical limiting analysis of phthalocyanines in polymer thin films
- Britton, Jonathan, Litwinski, Christian, Antunes, Edith M, Durmus, Mahmut, Chaukea, Vongani, Nyokong, Tebello
- Authors: Britton, Jonathan , Litwinski, Christian , Antunes, Edith M , Durmus, Mahmut , Chaukea, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232488 , vital:49996 , xlink:href="https://doi.org/10.1080/10601325.2013.736269"
- Description: This paper reports on the effect of embedding twelve phthalocyanines containing In, Ga, Zn and Al as central metals in polymer thin films on their optical limiting abilities. This paper also examines the effect of forming a covalent link between zinc tetraamino phthalocyanine (10) and poly (methyl acrylic acid) (PMAA), and Zn (11) or OHAl (12) octacarboxy phthalocyanines with polyethylenimine (PEI). The average film thickness (for phthalocyanines mixed or linked to polymers) of each Pc/Polymer films on glass was 95 μm. The hyperpolarizability of the twelve phthalocyanines was found to be in the range of 10−26 to 10−24 esu.L. This is significantly higher than the hyperpolarizabilities of these phthalocyanines in solution, which ranged from 10−30 to 10−26 esu.L. Degradation studies seem to indicate that placing a phthalocyanine within a polymer thin film may protect it slightly from photo- and thermal degradation.
- Full Text:
- Authors: Britton, Jonathan , Litwinski, Christian , Antunes, Edith M , Durmus, Mahmut , Chaukea, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232488 , vital:49996 , xlink:href="https://doi.org/10.1080/10601325.2013.736269"
- Description: This paper reports on the effect of embedding twelve phthalocyanines containing In, Ga, Zn and Al as central metals in polymer thin films on their optical limiting abilities. This paper also examines the effect of forming a covalent link between zinc tetraamino phthalocyanine (10) and poly (methyl acrylic acid) (PMAA), and Zn (11) or OHAl (12) octacarboxy phthalocyanines with polyethylenimine (PEI). The average film thickness (for phthalocyanines mixed or linked to polymers) of each Pc/Polymer films on glass was 95 μm. The hyperpolarizability of the twelve phthalocyanines was found to be in the range of 10−26 to 10−24 esu.L. This is significantly higher than the hyperpolarizabilities of these phthalocyanines in solution, which ranged from 10−30 to 10−26 esu.L. Degradation studies seem to indicate that placing a phthalocyanine within a polymer thin film may protect it slightly from photo- and thermal degradation.
- Full Text:
Overcrowding of false codling moth, Thaumatotibia leucotreta (Meyrick) leads to the isolation of five new Cryptophlebia leucotreta granulovirus (CrleGV-SA) isolates
- 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: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419360 , vital:71637 , xlink:href="https://doi.org/10.1016/j.jip.2012.12.008"
- Description: False codling moth, Thaumatotibia leucotreta (Meyrick) is a serious pest of economic importance to the South African fruit industry. As part of sustainable efforts to control this pest, biological control options that involve the application of baculovirus-based biopesticides such as Cryptogran and Cryptex (both formulated with a South African isolate of Cryptophlebia leucotreta granulovirus, CrleGV-SA) are popularly used by farmers. In order to safeguard the integrity of these biopesticides as well as protect against any future development of resistance in the host, we conducted a study to bioprospect for additional CrleGV isolates as alternatives to existing ones. Using overcrowding as an induction method for latent infection, we recovered five new CrleGV isolates (CrleGV-SA Ado, CrleGV-SA Mbl, CrleGV-SA Cit, CrleGV-SA MixC and CrleGV-SA Nels). Single restriction endonuclease (REN) analysis of viral genomic DNA extracted from purified occlusion bodies showed that isolates differed in their DNA profiles. Partial sequencing of granulin and egt genes from the different isolates and multiple alignments of nucleotide sequences revealed the presence of single nucleotide polymorphisms (SNPs), some of which resulted in amino acid substitutions in the protein sequence. Based on these findings as well as comparisons with other documented CrleGV isolates, we propose two phylogenetic groups for CrleGV-SA isolates recovered in this study.
- Full Text:
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419360 , vital:71637 , xlink:href="https://doi.org/10.1016/j.jip.2012.12.008"
- Description: False codling moth, Thaumatotibia leucotreta (Meyrick) is a serious pest of economic importance to the South African fruit industry. As part of sustainable efforts to control this pest, biological control options that involve the application of baculovirus-based biopesticides such as Cryptogran and Cryptex (both formulated with a South African isolate of Cryptophlebia leucotreta granulovirus, CrleGV-SA) are popularly used by farmers. In order to safeguard the integrity of these biopesticides as well as protect against any future development of resistance in the host, we conducted a study to bioprospect for additional CrleGV isolates as alternatives to existing ones. Using overcrowding as an induction method for latent infection, we recovered five new CrleGV isolates (CrleGV-SA Ado, CrleGV-SA Mbl, CrleGV-SA Cit, CrleGV-SA MixC and CrleGV-SA Nels). Single restriction endonuclease (REN) analysis of viral genomic DNA extracted from purified occlusion bodies showed that isolates differed in their DNA profiles. Partial sequencing of granulin and egt genes from the different isolates and multiple alignments of nucleotide sequences revealed the presence of single nucleotide polymorphisms (SNPs), some of which resulted in amino acid substitutions in the protein sequence. Based on these findings as well as comparisons with other documented CrleGV isolates, we propose two phylogenetic groups for CrleGV-SA isolates recovered in this study.
- Full Text:
Oxovanadium (IV)-containing poly (styrene-co-4′-ethenyl-2-hydroxyphenylimidazole) electrospun nanofibers for the catalytic oxidation of thioanisole
- Walmsley, Ryan S, Litwinski, Christian, Antunes, Edith M, Hlangothi, Percy, Hosten, Eric C, McCleland, Cedric, Nyokong, Tebello, Torto, Nelson, Tshentu, Zenixole R
- Authors: Walmsley, Ryan S , Litwinski, Christian , Antunes, Edith M , Hlangothi, Percy , Hosten, Eric C , McCleland, Cedric , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241665 , vital:50959 , xlink:href="https://doi.org/10.1016/j.molcata.2013.07.018"
- Description: The catalytic fibers have been fabricated by the electrospinning of a copolymer of styrene and 2-(2′-hydroxy-4′-ethenylphenyl)imidazole {p(ST-co-VPIM)} followed by a reaction with a methanolic vanadyl solution to afford the oxovanadium(IV)-containing poly(styrene-co-4′-ethenyl-2-hydroxyphenylimidazole) fibers {p(ST-co-VPIM)-VO fibers}. The relationship between polymer concentration and fiber diameter was investigated, and at high concentration (20 wt%) the fibers were quite large (average diameter of 3.8 μm) but as the concentration was reduced fibers of much lower diameter were produced (0.6 μm using 8 wt%). The BET surface area for p(ST-co-VPIM) fibers (0.6 μm diameter) was 47.9 m2 g−1 and functionalization of p(ST-co-VPIM) with vanadyl resulted in an increase in surface area to 60.7 m2 g−1 for p(ST-co-VPIM)-VO. The presence of vanadyl was confirmed by XPS and EPR. The EPR spectral analyses depicted complex speciation of vanadium within these polymer supports. These catalytic fibers were applied under batch and continuous flow conditions for the catalytic oxidation of thioanisole using hydrogen peroxide. The continuous flow method gave excellent and constant conversion throughout the 10 h period studied. The leaching of vanadium from the fiber support was 4% over the 10 h period indicating a significant stability of the material.
- Full Text:
- Authors: Walmsley, Ryan S , Litwinski, Christian , Antunes, Edith M , Hlangothi, Percy , Hosten, Eric C , McCleland, Cedric , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241665 , vital:50959 , xlink:href="https://doi.org/10.1016/j.molcata.2013.07.018"
- Description: The catalytic fibers have been fabricated by the electrospinning of a copolymer of styrene and 2-(2′-hydroxy-4′-ethenylphenyl)imidazole {p(ST-co-VPIM)} followed by a reaction with a methanolic vanadyl solution to afford the oxovanadium(IV)-containing poly(styrene-co-4′-ethenyl-2-hydroxyphenylimidazole) fibers {p(ST-co-VPIM)-VO fibers}. The relationship between polymer concentration and fiber diameter was investigated, and at high concentration (20 wt%) the fibers were quite large (average diameter of 3.8 μm) but as the concentration was reduced fibers of much lower diameter were produced (0.6 μm using 8 wt%). The BET surface area for p(ST-co-VPIM) fibers (0.6 μm diameter) was 47.9 m2 g−1 and functionalization of p(ST-co-VPIM) with vanadyl resulted in an increase in surface area to 60.7 m2 g−1 for p(ST-co-VPIM)-VO. The presence of vanadyl was confirmed by XPS and EPR. The EPR spectral analyses depicted complex speciation of vanadium within these polymer supports. These catalytic fibers were applied under batch and continuous flow conditions for the catalytic oxidation of thioanisole using hydrogen peroxide. The continuous flow method gave excellent and constant conversion throughout the 10 h period studied. The leaching of vanadium from the fiber support was 4% over the 10 h period indicating a significant stability of the material.
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Perceptions and use of public green space is influenced by its relative abundance in two small towns in South Africa
- Shackleton, Charlie M, Blair, Andrew
- Authors: Shackleton, Charlie M , Blair, Andrew
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181026 , vital:43688 , xlink:href="https://doi.org/10.1016/j.landurbplan.2013.01.011"
- Description: The challenges in planning and maintaining urban public green spaces in poor towns of the developing world differ markedly from those of the developed world. This paper reports on residents’ perceptions, use and willingness to get involved in urban public green space (PGS) issues in two poor towns in South Africa which differed markedly in the amount of PGS. The disparities in PGS between the two towns were also replicated in different suburbs within the two towns. We hypothesised that levels of dissatisfaction would be highest in those suburbs and the town with the least PGS. The results indicated that the distance from residents’ homesteads to the nearest PGS was similar across towns and suburbs. Most residents felt that having accessible PGS was important, and the majority agreed that there was insufficient PGS in their respective town and suburb, and that the local municipality did not do enough in providing PGS or maintaining what there was. The level of dissatisfaction with the amount and condition of PGS was generally highest in the suburbs and town with the least PGS. Many felt that the municipality had insufficient commitment and funds to adequately maintain PGS, and consequently the willingness of residents to get involved through either a commitment of time or funds was high. The more affluent town and suburbs were willing to pay more than the poorer ones, and the poorer ones were willing to provide more time than the more affluent ones.
- Full Text:
- Authors: Shackleton, Charlie M , Blair, Andrew
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181026 , vital:43688 , xlink:href="https://doi.org/10.1016/j.landurbplan.2013.01.011"
- Description: The challenges in planning and maintaining urban public green spaces in poor towns of the developing world differ markedly from those of the developed world. This paper reports on residents’ perceptions, use and willingness to get involved in urban public green space (PGS) issues in two poor towns in South Africa which differed markedly in the amount of PGS. The disparities in PGS between the two towns were also replicated in different suburbs within the two towns. We hypothesised that levels of dissatisfaction would be highest in those suburbs and the town with the least PGS. The results indicated that the distance from residents’ homesteads to the nearest PGS was similar across towns and suburbs. Most residents felt that having accessible PGS was important, and the majority agreed that there was insufficient PGS in their respective town and suburb, and that the local municipality did not do enough in providing PGS or maintaining what there was. The level of dissatisfaction with the amount and condition of PGS was generally highest in the suburbs and town with the least PGS. Many felt that the municipality had insufficient commitment and funds to adequately maintain PGS, and consequently the willingness of residents to get involved through either a commitment of time or funds was high. The more affluent town and suburbs were willing to pay more than the poorer ones, and the poorer ones were willing to provide more time than the more affluent ones.
- Full Text:
Persistence and virulence of promising entomopathogenic fungal isolates for use in citrus orchards in South Africa
- 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: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416893 , vital:71394 , xlink:href="https://doi.org/10.1080/09583157.2013.819489"
- Description: Thaumatotibia leucotreta (Meyrick) (1912) (Lepidoptera: Tortricidae) is a key economic pest of citrus in South Africa. Although a variety of control options are available, none currently registered target the soil-dwelling life stages of the pest. Three fungal isolates, two Metarhizium anisopliae sensu lato Metschnikoff (Sorokin) isolates (G 11 3 L6 and FCM Ar 23 B3) and one Beauveria bassiana sensu lato Balsamo (Vuillemin) isolate (G Ar 17 B3) have been identified as showing the greatest potential against T. leucotreta soil-dwelling life stages. Since environmental persistence is an important factor in the success of entomopathogenic fungi against soil pests, the isolates, along with two commercial isolates (B. bassiana Eco-Bb® and M. anisopliae ICIPE 69), were subjected to a six-month field persistence trial. Every month after burial of the fungal isolates, inside net bags, in orchard soil, the number of colony forming units (CFUs) per gram of soil was measured and the viability of the conidia was assessed using bioassays. All isolates investigated were capable of persisting in the soil for the duration of the trial period and in addition, were capable of initiating infection in T. leucotreta late fifth instar larvae and subsequent pupae. However, with the exception of the commercial isolates which showed some correlation, no correlation was found between the number of CFUs recorded and percentage T. leucotreta mycosis. Persistence of entomopathogenic fungi in the field is affected by a series of factors, and although the effect of these factors was not measured, the data have provided preliminary evidence towards the persistence capability of these candidate biopesticides against T. leucotreta.
- Full Text:
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416893 , vital:71394 , xlink:href="https://doi.org/10.1080/09583157.2013.819489"
- Description: Thaumatotibia leucotreta (Meyrick) (1912) (Lepidoptera: Tortricidae) is a key economic pest of citrus in South Africa. Although a variety of control options are available, none currently registered target the soil-dwelling life stages of the pest. Three fungal isolates, two Metarhizium anisopliae sensu lato Metschnikoff (Sorokin) isolates (G 11 3 L6 and FCM Ar 23 B3) and one Beauveria bassiana sensu lato Balsamo (Vuillemin) isolate (G Ar 17 B3) have been identified as showing the greatest potential against T. leucotreta soil-dwelling life stages. Since environmental persistence is an important factor in the success of entomopathogenic fungi against soil pests, the isolates, along with two commercial isolates (B. bassiana Eco-Bb® and M. anisopliae ICIPE 69), were subjected to a six-month field persistence trial. Every month after burial of the fungal isolates, inside net bags, in orchard soil, the number of colony forming units (CFUs) per gram of soil was measured and the viability of the conidia was assessed using bioassays. All isolates investigated were capable of persisting in the soil for the duration of the trial period and in addition, were capable of initiating infection in T. leucotreta late fifth instar larvae and subsequent pupae. However, with the exception of the commercial isolates which showed some correlation, no correlation was found between the number of CFUs recorded and percentage T. leucotreta mycosis. Persistence of entomopathogenic fungi in the field is affected by a series of factors, and although the effect of these factors was not measured, the data have provided preliminary evidence towards the persistence capability of these candidate biopesticides against T. leucotreta.
- Full Text:
Photodegradation of Orange-G using zinc octacarboxyphthalocyanine supported on Fe3O4 nanoparticles
- Modisha, Phillimon, Nyokong, Tebello, Antunes, Edith M
- Authors: Modisha, Phillimon , Nyokong, Tebello , Antunes, Edith M
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241653 , vital:50958 , xlink:href="https://doi.org/10.1016/j.molcata.2013.09.030"
- Description: Zinc octacarboxy phthalocyanine (ZnOCPc) was covalently immobilized on the surface of magnetite nanoparticles (MNPs) for the photocatalytic degradation of Orange G (OG) under visible light irradiation. It is noteworthy that the catalyst can be easily recovered using an external magnet and that it is reusable. The ZnOCPc remained bound to the MNP surface even after 25 min of photolysis as confirmed by the FT-IR and X-ray diffraction spectra. Kinetic analysis shows that the photodegradation rates of OG can be approximated to be pseudo-first order, according to the Langmuir–Hinshelwood kinetics model.
- Full Text:
- Authors: Modisha, Phillimon , Nyokong, Tebello , Antunes, Edith M
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241653 , vital:50958 , xlink:href="https://doi.org/10.1016/j.molcata.2013.09.030"
- Description: Zinc octacarboxy phthalocyanine (ZnOCPc) was covalently immobilized on the surface of magnetite nanoparticles (MNPs) for the photocatalytic degradation of Orange G (OG) under visible light irradiation. It is noteworthy that the catalyst can be easily recovered using an external magnet and that it is reusable. The ZnOCPc remained bound to the MNP surface even after 25 min of photolysis as confirmed by the FT-IR and X-ray diffraction spectra. Kinetic analysis shows that the photodegradation rates of OG can be approximated to be pseudo-first order, according to the Langmuir–Hinshelwood kinetics model.
- Full Text:
Photophysical and photochemical properties of a novel thiol terminated low symmetry zinc phthalocyanine complex and its gold nanoparticles conjugate
- Mthethwa, Thandekile P, Durmus, Mahmut, Nyokong, Tebello
- Authors: Mthethwa, Thandekile P , Durmus, Mahmut , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231474 , vital:49891 , xlink:href="https://doi.org/10.1039/C3DT32698E"
- Description: A novel thiol functionalized zinc phthalocyanine complex (ZnPcSH) is reported in this work. This complex was conjugated to gold nanoparticles. The photophysical and photochemical properties of the complex and the conjugate were investigated. Upon conjugation a blue shift was observed from the UV-Vis spectra. The conjugate showed a decrease in the fluorescence quantum yield and lifetime. An increase in the triplet quantum yield and lifetime was observed for ZnPcSH following conjugation to gold nanoparticles. Both ZnPcSH and its conjugate with gold nanoparticles showed high singlet oxygen quantum yields with the conjugate being higher than the Pc alone.
- Full Text:
- Authors: Mthethwa, Thandekile P , Durmus, Mahmut , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231474 , vital:49891 , xlink:href="https://doi.org/10.1039/C3DT32698E"
- Description: A novel thiol functionalized zinc phthalocyanine complex (ZnPcSH) is reported in this work. This complex was conjugated to gold nanoparticles. The photophysical and photochemical properties of the complex and the conjugate were investigated. Upon conjugation a blue shift was observed from the UV-Vis spectra. The conjugate showed a decrease in the fluorescence quantum yield and lifetime. An increase in the triplet quantum yield and lifetime was observed for ZnPcSH following conjugation to gold nanoparticles. Both ZnPcSH and its conjugate with gold nanoparticles showed high singlet oxygen quantum yields with the conjugate being higher than the Pc alone.
- Full Text:
Physicochemical properties of a zinc phthalocyanine–pyrene conjugate adsorbed onto single walled carbon nanotubes
- Ogbodu, Racheal O, Antunes, Edith M, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242314 , vital:51029 , xlink:href="https://doi.org/10.1039/C3DT50335F"
- Description: A conjugate between zinc monoamino phthalocyanine (ZnMAPc) and pyrene (Py) represented as ZnMAPc–Py (complex 3) was synthesized and characterized by various spectroscopic techniques and by elemental analysis. This manuscript also reports on the photochemical and photophysical properties of 3. This new compound exhibited higher triplet, fluorescence and singlet oxygen quantum yields in comparison to the phthalocyanine alone, hence showing the advantages of attaching pyrene to the Pc without breaking the conjugation. We also observed a decrease in photophysical parameters upon adsorbing the ZnMAPc–Py complex onto single walled carbon nanotubes (SWCNT). However, ZnMAPc–Py still generated some singlet oxygen when adsorbed onto SWCNT.
- Full Text:
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242314 , vital:51029 , xlink:href="https://doi.org/10.1039/C3DT50335F"
- Description: A conjugate between zinc monoamino phthalocyanine (ZnMAPc) and pyrene (Py) represented as ZnMAPc–Py (complex 3) was synthesized and characterized by various spectroscopic techniques and by elemental analysis. This manuscript also reports on the photochemical and photophysical properties of 3. This new compound exhibited higher triplet, fluorescence and singlet oxygen quantum yields in comparison to the phthalocyanine alone, hence showing the advantages of attaching pyrene to the Pc without breaking the conjugation. We also observed a decrease in photophysical parameters upon adsorbing the ZnMAPc–Py complex onto single walled carbon nanotubes (SWCNT). However, ZnMAPc–Py still generated some singlet oxygen when adsorbed onto SWCNT.
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Physicochemical properties of zinc monoamino phthalocyanine conjugated to folic acid and single walled carbon nanotubes
- Ogbodu, Racheal O, Antunes, Edith M, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241761 , vital:50967 , xlink:href="https://doi.org/10.1016/j.poly.2013.05.025"
- Description: This study reports on the photophysical and photochemical behavior of the conjugates formed by covalent and non-covalent bonding between zinc monoamino phthalocyanine (ZnMAPc) and either single walled carbon nanotubes (SWCNTs) or folic acid (FA). The conjugates were characterized using FTIR, X-ray powder diffractometry, thermogravimetric analyses, transmission electron microscopy and Raman spectroscopy. 1H NMR and mass spectroscopies were only employed for ZnMAPc–FA conjugate. There was a slight increase in the triplet and singlet oxygen quantum yields on conjugating ZnMAPc to SWCNTs (or FA), while a decrease in the photophysical and photochemical parameters were observed upon adsorption of the ZnMAPc–FA conjugate to SWCNTs.
- Full Text:
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241761 , vital:50967 , xlink:href="https://doi.org/10.1016/j.poly.2013.05.025"
- Description: This study reports on the photophysical and photochemical behavior of the conjugates formed by covalent and non-covalent bonding between zinc monoamino phthalocyanine (ZnMAPc) and either single walled carbon nanotubes (SWCNTs) or folic acid (FA). The conjugates were characterized using FTIR, X-ray powder diffractometry, thermogravimetric analyses, transmission electron microscopy and Raman spectroscopy. 1H NMR and mass spectroscopies were only employed for ZnMAPc–FA conjugate. There was a slight increase in the triplet and singlet oxygen quantum yields on conjugating ZnMAPc to SWCNTs (or FA), while a decrease in the photophysical and photochemical parameters were observed upon adsorption of the ZnMAPc–FA conjugate to SWCNTs.
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Playing with the forest: Invasive alien plants, policy and protected areas in India
- Kannan, Ramesh, Shackleton, Charlie M, Shaanker, Ramanan U
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182334 , vital:43821 , xlink:href="https://www.jstor.org/stable/24092395"
- Description: Protected areas (PAs) are inviolate and invaluable landscapes that promote the in situ conservation of endangered, threatened and rare species. Accordingly, and in keeping with this definition, PA managers ensure that PAs are free from fire, poaching, grazing, non-timber forest products collection, mining, etc. In India, following the Indian Wildlife (Protection) Act (1972), there are today 102 and 515 National Parks and Wildlife Sanctuaries respectively. Many of these have in recent decades been heavily threatened by the spread of invasive alien plant species, notable among them being Lantana and Eupatorium. These species may have usurped as yet unestimated number of native plants and fauna, besides depressing the reproduction of native plant species. In fact, it is realized that the threat to biodiversity by invasive alien species (IAS) may only be second to that of fragmentation. Yet there seems to be no major attempts to eradicate, contain or manage IAS in PAs. Ironically, the justification for the lack of action lies in the definition of PAs - that they need to be kept inviolate and therefore above any active intervention. In this article we bring home this serious contradiction in the approach to management of PAs in India and discuss the philosophical origins of this practice. We argue that if we are to protect our PAs from the serious scourge of invasive species, we would have to relook at the policy governing PA management and revise it to be more inclusive than exclusive.
- Full Text:
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182334 , vital:43821 , xlink:href="https://www.jstor.org/stable/24092395"
- Description: Protected areas (PAs) are inviolate and invaluable landscapes that promote the in situ conservation of endangered, threatened and rare species. Accordingly, and in keeping with this definition, PA managers ensure that PAs are free from fire, poaching, grazing, non-timber forest products collection, mining, etc. In India, following the Indian Wildlife (Protection) Act (1972), there are today 102 and 515 National Parks and Wildlife Sanctuaries respectively. Many of these have in recent decades been heavily threatened by the spread of invasive alien plant species, notable among them being Lantana and Eupatorium. These species may have usurped as yet unestimated number of native plants and fauna, besides depressing the reproduction of native plant species. In fact, it is realized that the threat to biodiversity by invasive alien species (IAS) may only be second to that of fragmentation. Yet there seems to be no major attempts to eradicate, contain or manage IAS in PAs. Ironically, the justification for the lack of action lies in the definition of PAs - that they need to be kept inviolate and therefore above any active intervention. In this article we bring home this serious contradiction in the approach to management of PAs in India and discuss the philosophical origins of this practice. We argue that if we are to protect our PAs from the serious scourge of invasive species, we would have to relook at the policy governing PA management and revise it to be more inclusive than exclusive.
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Poly methyl methacrylate films containing metallophthalocyanines in the presence of CdTe quantum dots
- Britton, Jonathan, Durmus, Mahmut, Chauke, Vongani, Nyokong, Tebello
- Authors: Britton, Jonathan , Durmus, Mahmut , Chauke, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241629 , vital:50956 , xlink:href="https://doi.org/10.1016/j.molstruc.2013.09.017"
- Description: Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in poly (methyl methacrylate) polymer in the absence and presence of quantum dots (QDs) in an effort to create the most optimal optical limiting material. The QDs employed were CdTe–TGA (TGA = thioglylcolic acid). Triplet lifetimes generally increased as the value of the ratio of absorption cross sections of the excited state to that of the ground state (k) decreased on addition of CdTe–TGA to the phthalocyanines. The saturation energy density (Fsat) values were generally smaller in the films when compared to the solutions. Fsat, Ilim, Im[χ(3)]/α and γ all gave values which were of optimal range (i.e. the Im[χ(3)]/α and γ values were high enough to ensure adequate optical limiting but not too high to make the compounds behave like optical filters. Also, the Fsat and Ilim values were small enough to mean that the optical limiting process started at an intensity which was not too high) for complex 10 containing Zn central metal and tetrasubstituted with amino groups.
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- Authors: Britton, Jonathan , Durmus, Mahmut , Chauke, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241629 , vital:50956 , xlink:href="https://doi.org/10.1016/j.molstruc.2013.09.017"
- Description: Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in poly (methyl methacrylate) polymer in the absence and presence of quantum dots (QDs) in an effort to create the most optimal optical limiting material. The QDs employed were CdTe–TGA (TGA = thioglylcolic acid). Triplet lifetimes generally increased as the value of the ratio of absorption cross sections of the excited state to that of the ground state (k) decreased on addition of CdTe–TGA to the phthalocyanines. The saturation energy density (Fsat) values were generally smaller in the films when compared to the solutions. Fsat, Ilim, Im[χ(3)]/α and γ all gave values which were of optimal range (i.e. the Im[χ(3)]/α and γ values were high enough to ensure adequate optical limiting but not too high to make the compounds behave like optical filters. Also, the Fsat and Ilim values were small enough to mean that the optical limiting process started at an intensity which was not too high) for complex 10 containing Zn central metal and tetrasubstituted with amino groups.
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Probing the sensitive and selective luminescent detection of peroxynitrite using thiol-capped CdTe and CdTe@ ZnS quantum dots
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193757 , vital:45393 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.08.002"
- Description: CdTe and CdTe@ZnS quantum dots (QDs) capped with 3-mercaptopropionic acid (MPA), thioglycolic acid (TGA), or glutathione (GSH) have been employed for the first time as luminescent probes for the sensitive and selective detection of peroxynitrite (ONOO−) in aqueous solution. The sensitivity of the proposed probe followed the order: MPA–TGA–CdTe@ZnS>GSH–TGA–CdTe@ZnS>MPA–CdTe QDs. The varying degree of quenching is elucidated based on the QD–thiolate bond of CdTe@ZnS being more sensitive to oxidation from ONOO− than CdTe. The selectivity of the probe in the presence of co-existing species followed the order: GSH–TGA–CdTe@ZnS>MPA–TGA–CdTe@ZnS>MPA–CdTe QDs. QDs capped with MPA showed less selectivity for ONOO− than GSH. The best limit of detection (LOD) of 12.6 nM was obtained for MPA–TGA–CdTe@ZnS QDs. Time-resolved fluorescence measurements indicated that the interaction between ONOO− and the QDs is static in nature.
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- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193757 , vital:45393 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.08.002"
- Description: CdTe and CdTe@ZnS quantum dots (QDs) capped with 3-mercaptopropionic acid (MPA), thioglycolic acid (TGA), or glutathione (GSH) have been employed for the first time as luminescent probes for the sensitive and selective detection of peroxynitrite (ONOO−) in aqueous solution. The sensitivity of the proposed probe followed the order: MPA–TGA–CdTe@ZnS>GSH–TGA–CdTe@ZnS>MPA–CdTe QDs. The varying degree of quenching is elucidated based on the QD–thiolate bond of CdTe@ZnS being more sensitive to oxidation from ONOO− than CdTe. The selectivity of the probe in the presence of co-existing species followed the order: GSH–TGA–CdTe@ZnS>MPA–TGA–CdTe@ZnS>MPA–CdTe QDs. QDs capped with MPA showed less selectivity for ONOO− than GSH. The best limit of detection (LOD) of 12.6 nM was obtained for MPA–TGA–CdTe@ZnS QDs. Time-resolved fluorescence measurements indicated that the interaction between ONOO− and the QDs is static in nature.
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Real-time distributed malicious traffic monitoring for honeypots and network telescopes
- Hunter, Samuel O, Irwin, Barry V W, Stalmans, Etienne
- Authors: Hunter, Samuel O , Irwin, Barry V W , Stalmans, Etienne
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429660 , vital:72630 , 10.1109/ISSA.2013.6641050
- Description: Network telescopes and honeypots have been used with great success to record malicious network traffic for analysis, however, this is often done off-line well after the traffic was observed. This has left us with only a cursory understanding of malicious hosts and no knowledge of the software they run, uptime or other malicious activity they may have participated in. This work covers a messaging framework (rDSN) that was developed to allow for the real-time analysis of malicious traffic. This data was captured from multiple, distributed honeypots and network telescopes. Data was collected over a period of two months from these data sensors. Using this data new techniques for malicious host analysis and re-identification in dynamic IP address space were explored. An Automated Reconnaissance (AR) Framework was developed to aid the process of data collection, this framework was responsible for gathering information from malicious hosts through both passive and active fingerprinting techniques. From the analysis of this data; correlations between malicious hosts were identified based on characteristics such as Operating System, targeted service, location and services running on the malicious hosts. An initial investigation in Latency Based Multilateration (LBM), a novel technique to assist in host re-identification was tested and proved successful as a supporting metric for host re-identification.
- Full Text:
- Authors: Hunter, Samuel O , Irwin, Barry V W , Stalmans, Etienne
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429660 , vital:72630 , 10.1109/ISSA.2013.6641050
- Description: Network telescopes and honeypots have been used with great success to record malicious network traffic for analysis, however, this is often done off-line well after the traffic was observed. This has left us with only a cursory understanding of malicious hosts and no knowledge of the software they run, uptime or other malicious activity they may have participated in. This work covers a messaging framework (rDSN) that was developed to allow for the real-time analysis of malicious traffic. This data was captured from multiple, distributed honeypots and network telescopes. Data was collected over a period of two months from these data sensors. Using this data new techniques for malicious host analysis and re-identification in dynamic IP address space were explored. An Automated Reconnaissance (AR) Framework was developed to aid the process of data collection, this framework was responsible for gathering information from malicious hosts through both passive and active fingerprinting techniques. From the analysis of this data; correlations between malicious hosts were identified based on characteristics such as Operating System, targeted service, location and services running on the malicious hosts. An initial investigation in Latency Based Multilateration (LBM), a novel technique to assist in host re-identification was tested and proved successful as a supporting metric for host re-identification.
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Reconstructing the history of introduction and spread of the invasive species, Lantana, at three spatial scales in India
- Kannan, Ramesh, Shackleton, Charlie M, Shaanker, Ramanan U
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181015 , vital:43687 , xlink:href="https://doi.org/10.1007/s10530-012-0365-z"
- Description: This study sought to reconstruct the history of Lantana invasion and spread in India by considering two questions; (a) from where, by who, and when were Lantana species introduced into India? and (b) given its long history in the country, is it still spreading or more or less stable? We critically evaluated the archival and historical information on plant imports by the European powers into India during the period before and after British colonization. We then reconstructed the path of spread by analyzing the spatio-temporal patterns of occurrence and distribution of Lantana in India at both the national and local scale using a GIS platform. The spread of Lantana across the globe started as early as the 1690s. The European colonial powers moved the plants from Latin America to Europe and to their colonial countries in the early 1800s. Lantana species were introduced in India from 1807 onwards and thereafter the colonial powers moved this plant across the country. Following its introduction into India, the spread of Lantana across the country, either through subsequent multiple introductions from Europe to different British cantonments, or through moving the plants between cantonments within India, were reasonably rapid spanning only a few decades. In the absence of a rigorous control program, the spread of Lantana has gone on unabated and thereby impacting both wildlife and biodiversity.
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- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181015 , vital:43687 , xlink:href="https://doi.org/10.1007/s10530-012-0365-z"
- Description: This study sought to reconstruct the history of Lantana invasion and spread in India by considering two questions; (a) from where, by who, and when were Lantana species introduced into India? and (b) given its long history in the country, is it still spreading or more or less stable? We critically evaluated the archival and historical information on plant imports by the European powers into India during the period before and after British colonization. We then reconstructed the path of spread by analyzing the spatio-temporal patterns of occurrence and distribution of Lantana in India at both the national and local scale using a GIS platform. The spread of Lantana across the globe started as early as the 1690s. The European colonial powers moved the plants from Latin America to Europe and to their colonial countries in the early 1800s. Lantana species were introduced in India from 1807 onwards and thereafter the colonial powers moved this plant across the country. Following its introduction into India, the spread of Lantana across the country, either through subsequent multiple introductions from Europe to different British cantonments, or through moving the plants between cantonments within India, were reasonably rapid spanning only a few decades. In the absence of a rigorous control program, the spread of Lantana has gone on unabated and thereby impacting both wildlife and biodiversity.
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Residency and small-scale movement behaviour of three endemic sparid fishes in their shallow rocky subtidal nursery habitat, South Africa
- Watt-Pringle, Peter A, Cowley, Paul D, Gotz, Albrecht
- Authors: Watt-Pringle, Peter A , Cowley, Paul D , Gotz, Albrecht
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443584 , vital:74135 , https://hdl.handle.net/10520/EJC137608
- Description: The residency and small-scale movements of early juveniles (175 mm fork length) of three sparid fish species were examined in the shallow subtidal zone along a 500 m stretch of rocky coastline near Schoenmakerskop (Eastern Cape Province, South Africa). A total of 12 blacktail (Diplodus capensis), 12 zebra (Diplodus hottentotus) and six white musselcracker (Sparodon durbanensis) were tagged using visible implant elastomer (VIE) tags. Underwater observations in four shallow rocky subtidal gullies and adjacent areas were made using snorkelling gear on a total of 37 days spanning 13 field trips over spring low tide periods between January and August 2006. The VIE tagging method was well suited to individually tag small juvenile fish with minimum disturbance. In general, the degree of residency of juveniles in the shallow rocky subtidal zone was species specific and dependent on the size of individuals. Juvenile zebra displayed the highest degree of residency followed by white musselcracker and blacktail, with re-sightings recorded on 53%, 40% and 10% of observation days, respectively. The high degree of residency by early juvenile sparids renders them vulnerable to localized coastal perturbations and climate change.
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- Authors: Watt-Pringle, Peter A , Cowley, Paul D , Gotz, Albrecht
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443584 , vital:74135 , https://hdl.handle.net/10520/EJC137608
- Description: The residency and small-scale movements of early juveniles (175 mm fork length) of three sparid fish species were examined in the shallow subtidal zone along a 500 m stretch of rocky coastline near Schoenmakerskop (Eastern Cape Province, South Africa). A total of 12 blacktail (Diplodus capensis), 12 zebra (Diplodus hottentotus) and six white musselcracker (Sparodon durbanensis) were tagged using visible implant elastomer (VIE) tags. Underwater observations in four shallow rocky subtidal gullies and adjacent areas were made using snorkelling gear on a total of 37 days spanning 13 field trips over spring low tide periods between January and August 2006. The VIE tagging method was well suited to individually tag small juvenile fish with minimum disturbance. In general, the degree of residency of juveniles in the shallow rocky subtidal zone was species specific and dependent on the size of individuals. Juvenile zebra displayed the highest degree of residency followed by white musselcracker and blacktail, with re-sightings recorded on 53%, 40% and 10% of observation days, respectively. The high degree of residency by early juvenile sparids renders them vulnerable to localized coastal perturbations and climate change.
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Rules of attraction: the role of bait in small mammal sampling at high altitude in South Africa
- Kok, Armand D, Parker, Daniel M, Barker, Nigel P
- Authors: Kok, Armand D , Parker, Daniel M , Barker, Nigel P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443936 , vital:74173 , https://doi.org/10.1080/15627020.2013.11407571
- Description: Baits or lures are commonly used for surveying small mammal communities, not only because they attract large numbers of these animals, but also because they provide sustenance for trapped individuals. In this study we used Sherman live traps with five bait treatments to sample small mammal populations at three high-altitude sites (>1700 m) in the Sneeuberg Mountain Complex of the Eastern Cape Province, South Africa.We investigated the influence of bait treatment on three parameters commonly recorded in small mammal surveys. In addition, we investigated how different bait treatments vary in measuring species richness using the Chao 2 species richness estimator together with rarefaction curves. Overall, 12 small mammal species were sampled. A combination of birdseed and banana captured the highest number of species (11) but the most successful bait overall was peanut butter and oats (greatest number of captures, recaptures, number of individuals and highest Shannon diversity). The Chao 2 richness estimator indicated that four of the five bait treatments reached their sampling capacity. Rarefaction curves indicated that all bait treatments are similar with regard to species accumulation. This could possibly be explained by odours left behind in traps as even un-baited traps (i.e. controls) captured seven different small mammal species. We conclude that the most suitable bait for surveying small mammals at high altitude in South Africa is peanut butter and oats. However, using peanut butter and oats in combination with other bait treatments will improve estimates of diversity when surveying small mammal communities.
- Full Text:
- Authors: Kok, Armand D , Parker, Daniel M , Barker, Nigel P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443936 , vital:74173 , https://doi.org/10.1080/15627020.2013.11407571
- Description: Baits or lures are commonly used for surveying small mammal communities, not only because they attract large numbers of these animals, but also because they provide sustenance for trapped individuals. In this study we used Sherman live traps with five bait treatments to sample small mammal populations at three high-altitude sites (>1700 m) in the Sneeuberg Mountain Complex of the Eastern Cape Province, South Africa.We investigated the influence of bait treatment on three parameters commonly recorded in small mammal surveys. In addition, we investigated how different bait treatments vary in measuring species richness using the Chao 2 species richness estimator together with rarefaction curves. Overall, 12 small mammal species were sampled. A combination of birdseed and banana captured the highest number of species (11) but the most successful bait overall was peanut butter and oats (greatest number of captures, recaptures, number of individuals and highest Shannon diversity). The Chao 2 richness estimator indicated that four of the five bait treatments reached their sampling capacity. Rarefaction curves indicated that all bait treatments are similar with regard to species accumulation. This could possibly be explained by odours left behind in traps as even un-baited traps (i.e. controls) captured seven different small mammal species. We conclude that the most suitable bait for surveying small mammals at high altitude in South Africa is peanut butter and oats. However, using peanut butter and oats in combination with other bait treatments will improve estimates of diversity when surveying small mammal communities.
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Seeing Fictions in Film
- Authors: Jones, Ward E
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275711 , vital:55072 , xlink:href="https://doi.org/10.1080/00048402.2013.818044"
- Description: Although its subtitle refers to an ‘epistemology of movies’, the claim at the heart of George M. Wilson’s dense and penetrating book is a bit of sophisticated phenomenology concerning our experience of narrative fiction films [Chs 2–4]. This phenomenological claim he calls the ‘Imagined Seeing Thesis’. When we watch narrative fiction films, we imagine that we are seeing real motion picture shots of the fictional events being portrayed.
- Full Text:
- Authors: Jones, Ward E
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275711 , vital:55072 , xlink:href="https://doi.org/10.1080/00048402.2013.818044"
- Description: Although its subtitle refers to an ‘epistemology of movies’, the claim at the heart of George M. Wilson’s dense and penetrating book is a bit of sophisticated phenomenology concerning our experience of narrative fiction films [Chs 2–4]. This phenomenological claim he calls the ‘Imagined Seeing Thesis’. When we watch narrative fiction films, we imagine that we are seeing real motion picture shots of the fictional events being portrayed.
- Full Text: