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
Isolation and structure elucidation of halogenated metabolites from Portieria hornemannii and Portieria tripinnata
- Authors: Adam, Mohammed
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64674 , vital:28591
- Description: The red marine algal genus, Portieria, is known to produce a number of potent cytotoxic compounds with anticancer potential. The most important anticancer lead produced by this genus is the compound halomon. Unfortunately, the lack of sufficient quantities of this compound hampered its further development. Two Portieria species, Portieria hornemannii and Portieria tripinnata, are found along the South African coastline. Recent studies, based on DNA analysis, suggest that Portieria hornemannii may in fact be divided into several cryptic species. The current project is part of a larger study designed to investigate the use of secondary metabolites to identify new marine algal species. In this study 1H NMR profiles of the organic extracts of selected Portieria spp were compared in order to identify new species. Selected compounds were then isolated and characterised as potential chemotaxonomic markers. Four halogenated monoterpenes were isolated from Portieria hornemannii. Two of these were new compounds 4-(3-bromo-4-chloro-4-methylpentyl)-3-chlorofuran-2(5H)-one, which were isomers of each other. The two known compounds had been previously isolated from Portieria hornemannii samples off the Madagascar coast. These compounds could prove to be useful as chemotaxonomic marker compounds, as they have never been isolated from any other species of marine algae. Three known halogenated monoterpenes were isolated from Portieria tripinnata. These compounds had been previously isolated from different species of marine algae and therefore, could not serve as chemotaxonomic marker compounds for this species of marine alga. Further work needs to be done on Portieria tripinnata, with regards to its chemistry, as it is a species of marine algae that has not been previously researched.
- Full Text:
- Date Issued: 2015
- Authors: Adam, Mohammed
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64674 , vital:28591
- Description: The red marine algal genus, Portieria, is known to produce a number of potent cytotoxic compounds with anticancer potential. The most important anticancer lead produced by this genus is the compound halomon. Unfortunately, the lack of sufficient quantities of this compound hampered its further development. Two Portieria species, Portieria hornemannii and Portieria tripinnata, are found along the South African coastline. Recent studies, based on DNA analysis, suggest that Portieria hornemannii may in fact be divided into several cryptic species. The current project is part of a larger study designed to investigate the use of secondary metabolites to identify new marine algal species. In this study 1H NMR profiles of the organic extracts of selected Portieria spp were compared in order to identify new species. Selected compounds were then isolated and characterised as potential chemotaxonomic markers. Four halogenated monoterpenes were isolated from Portieria hornemannii. Two of these were new compounds 4-(3-bromo-4-chloro-4-methylpentyl)-3-chlorofuran-2(5H)-one, which were isomers of each other. The two known compounds had been previously isolated from Portieria hornemannii samples off the Madagascar coast. These compounds could prove to be useful as chemotaxonomic marker compounds, as they have never been isolated from any other species of marine algae. Three known halogenated monoterpenes were isolated from Portieria tripinnata. These compounds had been previously isolated from different species of marine algae and therefore, could not serve as chemotaxonomic marker compounds for this species of marine alga. Further work needs to be done on Portieria tripinnata, with regards to its chemistry, as it is a species of marine algae that has not been previously researched.
- Full Text:
- Date Issued: 2015
Contributions to the study of a class of optimal control problems on the orthogonal groups SO(3) and SO(4)
- Authors: Adams, Ross Montague
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64826 , vital:28608
- Description: In this thesis we investigate a class of invariant optimal control problems, and their associated quadratic Hamilton-Poisson systems, on the orthogonal groups SO(3) and SO(4). Specifically, we are concerned with the class of left-invariant control affine systems. We begin by classifying all cost-extended systems on SO(3) under cost equivalence. (Cost-extended systems are closely related to optimal control problems.) A classification of all quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space so(3)*, under affine equivalence, is also obtained. For the normal forms obtained in our classification (of Hamilton-Poisson systems) we investigate the (Lyapunov) stability nature of the equilibria using spectral and energy-Casimir methods. For a subclass of these systems, we obtain analytic expressions for the integral curves of the associated Hamiltonian vector fields in terms of (basic) Jacobi elliptic functions. The explicit relationship between the classification of cost-extended systems on SO(3) and the classification of quadratic Hamilton- Poisson systems on so(3)* is provided. On SO(4), a classification of all left-invariant control affine systems under L-equivalence is obtained. We then determine which of these representatives are controllable, thus obtaining a classification under detached feedback equivalence. We also obtain a partial classification of quadratic Hamilton-Poisson systems on the Lie-Poisson space so(4)*. An investigation of the stability nature of the equilibria for a subclass of these systems is also done. Several illustrative examples of optimal control problems on the orthogonal group SO(3) are provided. More specifically, we consider an optimal control problem corresponding to a representative of our classification (of cost-extended system) for each possible number of control inputs. For each of these problems, we obtain explicit expressions for the extremal trajectories on the homogeneous space S2 by projecting the extremal trajectories on the group SO(3). The examples provided show how our classifications of cost-extended systems and Hamilton-Poisson systems can be used to obtain the optimal controls and the extremal trajectories corresponding to a large class of optimal control problems on SO(3). An example of a four-input optimal control problem on SO(4) is also provided. This example is provided to show how the solutions of certain problems on SO(4) can be related to the solutions of certain optimal control problems on SO(3).
- Full Text:
- Date Issued: 2015
- Authors: Adams, Ross Montague
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64826 , vital:28608
- Description: In this thesis we investigate a class of invariant optimal control problems, and their associated quadratic Hamilton-Poisson systems, on the orthogonal groups SO(3) and SO(4). Specifically, we are concerned with the class of left-invariant control affine systems. We begin by classifying all cost-extended systems on SO(3) under cost equivalence. (Cost-extended systems are closely related to optimal control problems.) A classification of all quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space so(3)*, under affine equivalence, is also obtained. For the normal forms obtained in our classification (of Hamilton-Poisson systems) we investigate the (Lyapunov) stability nature of the equilibria using spectral and energy-Casimir methods. For a subclass of these systems, we obtain analytic expressions for the integral curves of the associated Hamiltonian vector fields in terms of (basic) Jacobi elliptic functions. The explicit relationship between the classification of cost-extended systems on SO(3) and the classification of quadratic Hamilton- Poisson systems on so(3)* is provided. On SO(4), a classification of all left-invariant control affine systems under L-equivalence is obtained. We then determine which of these representatives are controllable, thus obtaining a classification under detached feedback equivalence. We also obtain a partial classification of quadratic Hamilton-Poisson systems on the Lie-Poisson space so(4)*. An investigation of the stability nature of the equilibria for a subclass of these systems is also done. Several illustrative examples of optimal control problems on the orthogonal group SO(3) are provided. More specifically, we consider an optimal control problem corresponding to a representative of our classification (of cost-extended system) for each possible number of control inputs. For each of these problems, we obtain explicit expressions for the extremal trajectories on the homogeneous space S2 by projecting the extremal trajectories on the group SO(3). The examples provided show how our classifications of cost-extended systems and Hamilton-Poisson systems can be used to obtain the optimal controls and the extremal trajectories corresponding to a large class of optimal control problems on SO(3). An example of a four-input optimal control problem on SO(4) is also provided. This example is provided to show how the solutions of certain problems on SO(4) can be related to the solutions of certain optimal control problems on SO(3).
- 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
Studies towards the development of novel antimalarial agents
- Authors: Adeyemi, Christiana Modupe
- Date: 2015
- Subjects: Antimalarials , Malaria , Drug resistance , Drug development , Enzyme inhibitors , Plasmodium
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54645 , vital:26596
- Description: Considerable efforts have been made in the modification of existing antimalarial drugs, and the support of incentive programmes have led to a drastic decrease in malaria cases reported by WHO during the past 6 years. However, the development of drug resistance threatens the eradication of this deadly disease and has prompted research on the synthesis of novel antimalarial drugs. Our research has involved the design and synthesis of novel benzylated phosphonate esters as potential 1-deoxy-D-xylose-5-phosphate reductoisomerase (DXR) inhibitors. A series of amidoalkylphosphonate esters were obtained by reacting various 3-subsituted anilines and heterocyclic amines with chloroalkanoyl chlorides and reacting the resulting chloroalkanamides with triethyl phosphite using Michaelis-Arbuzov methodology. Benzylation of the phosphonate esters afforded a series of novel N-benzylated derivatives in good yields and these compounds were fully characterised by NMR and HRMS methods. Several approaches to the introduction of a benzyl group at the C-2 position of the phosphonate ester derivatives have been explored, leading unexpectedly to the isolation of unprecedented tetrahydrofuranyl derivatives. Studies towards the preparation of potential bi-functional PfDXR / HIV-1 RT inhibitors have also been initiated. Preliminary in silico docking studies of selected non-benzylated and benzylated phosphonated derivatives into the Pf-DXR active-site has provided useful insight into the binding potential of these ligands. Bioassays have revealed a very low toxicity for all the synthesised phosphonated compounds and a number of these ligands also exhibit a promising inhibitory activity against the Plasmodium parasite.
- Full Text:
- Date Issued: 2015
- Authors: Adeyemi, Christiana Modupe
- Date: 2015
- Subjects: Antimalarials , Malaria , Drug resistance , Drug development , Enzyme inhibitors , Plasmodium
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54645 , vital:26596
- Description: Considerable efforts have been made in the modification of existing antimalarial drugs, and the support of incentive programmes have led to a drastic decrease in malaria cases reported by WHO during the past 6 years. However, the development of drug resistance threatens the eradication of this deadly disease and has prompted research on the synthesis of novel antimalarial drugs. Our research has involved the design and synthesis of novel benzylated phosphonate esters as potential 1-deoxy-D-xylose-5-phosphate reductoisomerase (DXR) inhibitors. A series of amidoalkylphosphonate esters were obtained by reacting various 3-subsituted anilines and heterocyclic amines with chloroalkanoyl chlorides and reacting the resulting chloroalkanamides with triethyl phosphite using Michaelis-Arbuzov methodology. Benzylation of the phosphonate esters afforded a series of novel N-benzylated derivatives in good yields and these compounds were fully characterised by NMR and HRMS methods. Several approaches to the introduction of a benzyl group at the C-2 position of the phosphonate ester derivatives have been explored, leading unexpectedly to the isolation of unprecedented tetrahydrofuranyl derivatives. Studies towards the preparation of potential bi-functional PfDXR / HIV-1 RT inhibitors have also been initiated. Preliminary in silico docking studies of selected non-benzylated and benzylated phosphonated derivatives into the Pf-DXR active-site has provided useful insight into the binding potential of these ligands. Bioassays have revealed a very low toxicity for all the synthesised phosphonated compounds and a number of these ligands also exhibit a promising inhibitory activity against the Plasmodium parasite.
- Full Text:
- Date Issued: 2015
Study of the biotransformations and microbiological properties of cymbopogon citratus
- Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Authors: Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Date: 2015
- Subjects: Lemongras , Essences and essential oils
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19737 , vital:43197
- Description: Variations in the essential oil yield, chemical composition and kinetics of chemical transformation, antibacterial, and antioxidant properties of the Cymbopogon citratus cultivated in Alice, Eastern Cape of South Africa, over a period of 12 months using the solvent-free microwave extraction and the modified forms of conventional hydrodistillation methods have been evaluated. The modified forms involve variation in the pH medium to effect extraction and to obtain the whole leaf extracts of Cymbopogon citratus (lemongrass). The GC-MS analyses of the essential oils revealed the presence of 10, 11, 13, and 9 principal compounds in the microwave, extraction, hydrodistillation (water-distilled), hydrodistillation (aciddistilled and hydrodistillation (base-distilled), respectively with citral being the prominent compound in all the various extraction methods, with the water-distilled method having the highest cumulative citral content under the period specified. Each of the components of the oils varied in quantity and quality of yield at different points of the year. Different extraction methods produce different compounds. Increase in the amount of citral content was observed during the maturation stage of Cymbopogon citratus in all the extraction methods. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration (MIC) values were determined on the oils and extracts of Cymbopogon citratus using agar dilution method. The essential oils obtained using all the methods of extraction showed activity against all the tested bacteria at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the acid-distilled varied between 1.25 and 5.0 mg mL-1, while those obtained by both water- and base-distilled showed equal activity on the microorganisms with the MIC ranging between 2.5 and 10 mg mL-1. The microwave extraction showed the least activity with the MIC of 10 mg mL-1. This however suggested that the oils obtained through acid-distillation showed the greatest activity than all other methods of extraction. Activity of the various extracts on bacteria showed that the ethanol extract had the highest activity on the tested organisms with MIC ranging between 0.625 and 1.25 mg mL-1. This was closely followed by the acid-extract (1.25 and 5.0 mg mL-1), methanol extract (1.25 and 10 mg mL-1), acetone extract (2.5 and 5.0 mg mL-1), and base extract (5.0 mg mL-1). Both cold water and hot water extracts showed the least activity of MIC, >10 mg mL-1. The antioxidant and free-radical scavenging activity of the obtained oils and extracts were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay, [(2,2ˊ-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS), nitric oxide and ferric reducing power assays. The oils and extracts showed DPPH radical scavenging ability, but not as high as the standard drugs. The base extract showed a higher reducing power than the standard drug, rutin. There were significant differences in the phytochemicals contents of the various leaf extracts. The acetone extract has the highest flavonol, proanthocyanidin, and alkaloid contents. The ethanol extract showed the highest amount of phenolic content with the acid extract, having the least. Thin layer chromatography (TLC) and column chromatography was employed to obtain different fractions of extracts using four eluent solvent systems of varying polarities: toluene, petroleum ether, hexane and ethyl acetate and sprayed with anisaldehyde. A single, visible spot of B-fraction was developed, collected and analyzed as 1-methyl-2,4,5- trinitroimidazole with renown valuable properties. , Thesis (PhD) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015
- Authors: Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Date: 2015
- Subjects: Lemongras , Essences and essential oils
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19737 , vital:43197
- Description: Variations in the essential oil yield, chemical composition and kinetics of chemical transformation, antibacterial, and antioxidant properties of the Cymbopogon citratus cultivated in Alice, Eastern Cape of South Africa, over a period of 12 months using the solvent-free microwave extraction and the modified forms of conventional hydrodistillation methods have been evaluated. The modified forms involve variation in the pH medium to effect extraction and to obtain the whole leaf extracts of Cymbopogon citratus (lemongrass). The GC-MS analyses of the essential oils revealed the presence of 10, 11, 13, and 9 principal compounds in the microwave, extraction, hydrodistillation (water-distilled), hydrodistillation (aciddistilled and hydrodistillation (base-distilled), respectively with citral being the prominent compound in all the various extraction methods, with the water-distilled method having the highest cumulative citral content under the period specified. Each of the components of the oils varied in quantity and quality of yield at different points of the year. Different extraction methods produce different compounds. Increase in the amount of citral content was observed during the maturation stage of Cymbopogon citratus in all the extraction methods. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration (MIC) values were determined on the oils and extracts of Cymbopogon citratus using agar dilution method. The essential oils obtained using all the methods of extraction showed activity against all the tested bacteria at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the acid-distilled varied between 1.25 and 5.0 mg mL-1, while those obtained by both water- and base-distilled showed equal activity on the microorganisms with the MIC ranging between 2.5 and 10 mg mL-1. The microwave extraction showed the least activity with the MIC of 10 mg mL-1. This however suggested that the oils obtained through acid-distillation showed the greatest activity than all other methods of extraction. Activity of the various extracts on bacteria showed that the ethanol extract had the highest activity on the tested organisms with MIC ranging between 0.625 and 1.25 mg mL-1. This was closely followed by the acid-extract (1.25 and 5.0 mg mL-1), methanol extract (1.25 and 10 mg mL-1), acetone extract (2.5 and 5.0 mg mL-1), and base extract (5.0 mg mL-1). Both cold water and hot water extracts showed the least activity of MIC, >10 mg mL-1. The antioxidant and free-radical scavenging activity of the obtained oils and extracts were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay, [(2,2ˊ-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS), nitric oxide and ferric reducing power assays. The oils and extracts showed DPPH radical scavenging ability, but not as high as the standard drugs. The base extract showed a higher reducing power than the standard drug, rutin. There were significant differences in the phytochemicals contents of the various leaf extracts. The acetone extract has the highest flavonol, proanthocyanidin, and alkaloid contents. The ethanol extract showed the highest amount of phenolic content with the acid extract, having the least. Thin layer chromatography (TLC) and column chromatography was employed to obtain different fractions of extracts using four eluent solvent systems of varying polarities: toluene, petroleum ether, hexane and ethyl acetate and sprayed with anisaldehyde. A single, visible spot of B-fraction was developed, collected and analyzed as 1-methyl-2,4,5- trinitroimidazole with renown valuable properties. , Thesis (PhD) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015
Specialist workforce development through mentoring: comparing collaborative programme evaluation using action research and realist evaluation
- Akhurst, Jacqueline E, Lawson, Sally
- Authors: Akhurst, Jacqueline E , Lawson, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143771 , vital:38281 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: This Workforce Innovations Programme (WIP) was for healthcare practitioners working in north east England. The innovative mentoring-focused WIP aimed to increase capacity and capability, and to improve services and outcomes for people living with long term neurological conditions. Mentors were matched with practitioners outside of their specialisms and focused on community and partnership working as alternatives to dominant modes of practice. This paper will highlight key outcomes and contextual challenges. It will explore collaborative action research for practitioner development, evidencing the participants’ learning. A medium term realist evaluation then provides data about the value of the WIP; and illustrates ways the programme worked for practitioners and people who used services, to support the drive for improved outcomes. It will compare and contrast the contributions of both forms of programme evaluation, and critique some of the discourses of workforce improvement initiatives.
- Full Text:
- Date Issued: 2015
- Authors: Akhurst, Jacqueline E , Lawson, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143771 , vital:38281 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: This Workforce Innovations Programme (WIP) was for healthcare practitioners working in north east England. The innovative mentoring-focused WIP aimed to increase capacity and capability, and to improve services and outcomes for people living with long term neurological conditions. Mentors were matched with practitioners outside of their specialisms and focused on community and partnership working as alternatives to dominant modes of practice. This paper will highlight key outcomes and contextual challenges. It will explore collaborative action research for practitioner development, evidencing the participants’ learning. A medium term realist evaluation then provides data about the value of the WIP; and illustrates ways the programme worked for practitioners and people who used services, to support the drive for improved outcomes. It will compare and contrast the contributions of both forms of programme evaluation, and critique some of the discourses of workforce improvement initiatives.
- Full Text:
- Date Issued: 2015
Keeping food on the table: 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
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70593 , vital:29678 , 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
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70593 , vital:29678 , 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
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
The landscape of childhood: play and place as tools to understanding children’s enviromental use and perceptions
- Alexander, Jamie K, Cocks, Michelle L, Shackleton, Charlie M
- Authors: Alexander, Jamie K , Cocks, Michelle L , Shackleton, Charlie M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141165 , vital:37949 , DOI: 10.1007/s10745-015-9755-z
- Description: Research has shown that children are the greatest users of natural areas and that childhood experiences strongly shape adults’ environmental values. This project was designed to ascertain children’s environmental uses and perceptions in two rural villages in the Eastern Cape, South Africa, utilising children’s use of the environment for play and their sense of place as key focus areas. Several factors influenced children’s environmental use, including safety fears, increased consumption of western media and environmental restrictions imposed by the state, revealing how South Africa’s high level of violence against women and children contributes to gendered environmental use and knowledge, and bringing about concern for children’s cultural identity in an increasingly westernised world.
- Full Text:
- Date Issued: 2015
- Authors: Alexander, Jamie K , Cocks, Michelle L , Shackleton, Charlie M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141165 , vital:37949 , DOI: 10.1007/s10745-015-9755-z
- Description: Research has shown that children are the greatest users of natural areas and that childhood experiences strongly shape adults’ environmental values. This project was designed to ascertain children’s environmental uses and perceptions in two rural villages in the Eastern Cape, South Africa, utilising children’s use of the environment for play and their sense of place as key focus areas. Several factors influenced children’s environmental use, including safety fears, increased consumption of western media and environmental restrictions imposed by the state, revealing how South Africa’s high level of violence against women and children contributes to gendered environmental use and knowledge, and bringing about concern for children’s cultural identity in an increasingly westernised world.
- Full Text:
- Date Issued: 2015
The palladacycle, AJ-5, exhibits anti-tumour and anti-cancer stem cell activity in breast cancer cells:
- Aliwaini, Saeb, Peres, Jade, Kröger, Wendy L, Blanckenberg, Angelique, de la Mare, Jo-Anne, Edkins, Adrienne L, Mapolie, Selwyn, Prince, Sharon
- Authors: Aliwaini, Saeb , Peres, Jade , Kröger, Wendy L , Blanckenberg, Angelique , de la Mare, Jo-Anne , Edkins, Adrienne L , Mapolie, Selwyn , Prince, Sharon
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164874 , vital:41180 , DOI: 10.1016/j.canlet.2014.11.027
- Description: Breast cancer is the most common malignancy amongst women worldwide but despite enormous efforts to address this problem, there is still limited success with most of the current therapeutic strategies. The current study describes the anti-cancer activity of a binuclear palladacycle complex (AJ-5) in oestrogen receptor positive (MCF7) and oestrogen receptor negative (MDA-MB-231) breast cancer cells as well as human breast cancer stem cells. AJ-5 is shown to induce DNA double strand breaks leading to intrinsic and extrinsic apoptosis and autophagy cell death pathways which are mediated by the p38 MAP kinase. This study provides evidence that AJ-5 is potentially an effective compound in the treatment of breast cancer.
- Full Text:
- Date Issued: 2015
- Authors: Aliwaini, Saeb , Peres, Jade , Kröger, Wendy L , Blanckenberg, Angelique , de la Mare, Jo-Anne , Edkins, Adrienne L , Mapolie, Selwyn , Prince, Sharon
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164874 , vital:41180 , DOI: 10.1016/j.canlet.2014.11.027
- Description: Breast cancer is the most common malignancy amongst women worldwide but despite enormous efforts to address this problem, there is still limited success with most of the current therapeutic strategies. The current study describes the anti-cancer activity of a binuclear palladacycle complex (AJ-5) in oestrogen receptor positive (MCF7) and oestrogen receptor negative (MDA-MB-231) breast cancer cells as well as human breast cancer stem cells. AJ-5 is shown to induce DNA double strand breaks leading to intrinsic and extrinsic apoptosis and autophagy cell death pathways which are mediated by the p38 MAP kinase. This study provides evidence that AJ-5 is potentially an effective compound in the treatment of breast cancer.
- Full Text:
- Date Issued: 2015
Oxford dictionary of journalism:
- Authors: Amner, Roderick J
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142656 , vital:38099 , DOI: 10.1080/23743670.2015.1041305
- Description: Tony Harcup is a self-confessed ‘hackademic’, a term which he defines in his Oxford dictionary of journalism as ‘a journalist who goes on to work in journalism education where they combine the roles of journalism (hack) and academic’ (p. 121). Harcup explains that hackademics perform this balancing act in the ‘hackademy’, a curious space within academe where journalism training intersects with Journalism Studies (a field of study which is nowadays often granted ‘upper case’ status), ‘sometimes with mutual respect and insight, sometimes with mutual suspicion and hostility’ (ibid.). And this tension is never far from the surface in many of the 1 300 definitions in this useful and absorbing dictionary.
- Full Text:
- Date Issued: 2015
- Authors: Amner, Roderick J
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142656 , vital:38099 , DOI: 10.1080/23743670.2015.1041305
- Description: Tony Harcup is a self-confessed ‘hackademic’, a term which he defines in his Oxford dictionary of journalism as ‘a journalist who goes on to work in journalism education where they combine the roles of journalism (hack) and academic’ (p. 121). Harcup explains that hackademics perform this balancing act in the ‘hackademy’, a curious space within academe where journalism training intersects with Journalism Studies (a field of study which is nowadays often granted ‘upper case’ status), ‘sometimes with mutual respect and insight, sometimes with mutual suspicion and hostility’ (ibid.). And this tension is never far from the surface in many of the 1 300 definitions in this useful and absorbing dictionary.
- Full Text:
- Date Issued: 2015
Azawan: precolonial musical culture and Saharawi nationalism in the refugee camps of the Hamada Desert in Algeria
- Authors: Amoros, Luis Gimenez
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59710 , vital:27641 , http://dx.doi.org/10.21504/amj.v10i1.1225
- Description: This article analyses Saharawi music as performed for the refugee community in the camps. I argue that the construction and evolution of Saharawi music in the camps is divided into two main areas: nationalism in relation to the decolonisation of Western Sahara, and maintenance of cultural values in Saharawi music found in the historical retention of the Haul modal system originating in precolonial Saharawi culture. Local audiences use the term Azawan to define the combination of nationalist sentiments and retention of their precolonial musical culture in Saharawi music.
- Full Text:
- Date Issued: 2015
- Authors: Amoros, Luis Gimenez
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59710 , vital:27641 , http://dx.doi.org/10.21504/amj.v10i1.1225
- Description: This article analyses Saharawi music as performed for the refugee community in the camps. I argue that the construction and evolution of Saharawi music in the camps is divided into two main areas: nationalism in relation to the decolonisation of Western Sahara, and maintenance of cultural values in Saharawi music found in the historical retention of the Haul modal system originating in precolonial Saharawi culture. Local audiences use the term Azawan to define the combination of nationalist sentiments and retention of their precolonial musical culture in Saharawi music.
- 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
Scientific frontiers in the management of coral reefs
- Aswani, Shankar, Mumby, Peter J, Baker, Andrew, Christie, Patrick, McCook, Laurence J, Steneck, Robert S, Richmond, Robert H
- Authors: Aswani, Shankar , Mumby, Peter J , Baker, Andrew , Christie, Patrick , McCook, Laurence J , Steneck, Robert S , Richmond, Robert H
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70582 , vital:29677 , https://doi.org/10.3389/fmars.2015.00050
- Description: Coral reefs are subjected globally to a variety of natural and anthropogenic stressors that often act synergistically. Today, reversing ongoing and future coral reef degradation presents significant challenges and countering this negative trend will take considerable efforts and investments. Scientific knowledge can inform and guide the requisite decision-making process and offer practical solutions to the problem of protection as the effects of climate change exacerbate. However, implementation of solutions presently lags far behind the pace required to reverse global declines, and there is a need for an urgent and significant step-up in the extent and range of strategies being implemented. In this paper, we consider scientific frontiers in natural and social science research that can help build stronger support for reef management and improve the efficacy of interventions. We cover various areas including: (1) enhancing the case for reef conservation and management, (2) dealing with local stressors on reefs, (3) addressing global climate change impacts, (4) and reviewing various approaches to the governance of coral reefs. In sum, we consider scientific frontiers in natural and social science that will require further attention in coming years as managers work toward building stronger support for reef management and improve the efficacy of local interventions.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Mumby, Peter J , Baker, Andrew , Christie, Patrick , McCook, Laurence J , Steneck, Robert S , Richmond, Robert H
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70582 , vital:29677 , https://doi.org/10.3389/fmars.2015.00050
- Description: Coral reefs are subjected globally to a variety of natural and anthropogenic stressors that often act synergistically. Today, reversing ongoing and future coral reef degradation presents significant challenges and countering this negative trend will take considerable efforts and investments. Scientific knowledge can inform and guide the requisite decision-making process and offer practical solutions to the problem of protection as the effects of climate change exacerbate. However, implementation of solutions presently lags far behind the pace required to reverse global declines, and there is a need for an urgent and significant step-up in the extent and range of strategies being implemented. In this paper, we consider scientific frontiers in natural and social science research that can help build stronger support for reef management and improve the efficacy of interventions. We cover various areas including: (1) enhancing the case for reef conservation and management, (2) dealing with local stressors on reefs, (3) addressing global climate change impacts, (4) and reviewing various approaches to the governance of coral reefs. In sum, we consider scientific frontiers in natural and social science that will require further attention in coming years as managers work toward building stronger support for reef management and improve the efficacy of local interventions.
- Full Text:
- Date Issued: 2015
Planning for the future: mapping anticipated environmental and social impacts in a nascent tourism destination
- Aswani, Shankar, Diedrich, Amy, Currier, Kitty
- Authors: Aswani, Shankar , Diedrich, Amy , Currier, Kitty
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145415 , vital:38436 , DOI: 10.1080/08941920.2015.1020582
- Description: Tourism is a significant driver of social and ecological change in developing countries, particularly in small-island states, which are susceptible to tourism impacts due to their particular social and environmental characteristics. In this article we present a participatory mapping approach to obtaining spatially explicit local perceptions of future environmental and social change resulting from tourism development, as well as addressing the different community conflicts that may arise through the introduction of tourism in the future in a Solomon Islands community. The results show that spatial conflicts within a community over territory and associated resources are likely to occur when designing natural resource management and tourism development plans. This knowledge can help us increase the future sustainability of tourism in nascent small-islands destinations, particularly in vulnerable regions such as Roviana, which have experienced very little tourism development and will likely experience more in the near future.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Diedrich, Amy , Currier, Kitty
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145415 , vital:38436 , DOI: 10.1080/08941920.2015.1020582
- Description: Tourism is a significant driver of social and ecological change in developing countries, particularly in small-island states, which are susceptible to tourism impacts due to their particular social and environmental characteristics. In this article we present a participatory mapping approach to obtaining spatially explicit local perceptions of future environmental and social change resulting from tourism development, as well as addressing the different community conflicts that may arise through the introduction of tourism in the future in a Solomon Islands community. The results show that spatial conflicts within a community over territory and associated resources are likely to occur when designing natural resource management and tourism development plans. This knowledge can help us increase the future sustainability of tourism in nascent small-islands destinations, particularly in vulnerable regions such as Roviana, which have experienced very little tourism development and will likely experience more in the near future.
- Full Text:
- Date Issued: 2015
Human harvesting impacts on managed areas: ecological effects of socially-compatible shellfish reserves
- Aswani, Shankar, Flores, Carola F, Broitman, Bernardo R
- Authors: Aswani, Shankar , Flores, Carola F , Broitman, Bernardo R
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124664 , vital:35644 , https://doi.10.1007/s11160-014-9376-4
- Description: We examined how human harvesting impacts on managed areas affect the abundance and size distribution of the edible mangrove shellfish Anadara granosa and Polymesoda spp. in the Roviana Lagoon, Solomon Islands. We tested two hypotheses: (1) in areas permanently and temporally closed to human exploitation, abundance and size distribution of these shellfish species is significantly greater than in sites open to exploitation and (2) moderate human disturbance of shell beds, particularly of Polymesoda spp., increases their abundance. Firstly, we studied perceptions of environmental states and processes coupled to foraging and management interventions to assess sociocultural influences on harvesting practices and ascertain the types of management regime that people would consider in a context where poaching and interloping are common practices. Secondly, we compared shellfish abundance and shell size from areas that were permanently protected, temporally reserved for communal harvest, and permanently open for exploitation. Thirdly, drawing from women’s local knowledge, we measured the abundance of Polymesoda spp. in relation to mud compactness in quadrats across the three management regimes. Results showed that both species were significantly more abundant in permanent and temporally closed sites than in open sites. In the mud compactness study, however, while shell abundance was greater in moderately compacted quadrats, there was no statistical relationship between mud compactness and shell abundance within or across the three management regimes. Results suggest that even under the strong impacts of poaching, temporally closed areas have more clams than open areas and are as effective as areas that are permanently closed nominally. The results also suggest that human harvesting regimes can influence the effectiveness of local management decisions and thus are important when designing community-based conservation programs in the Solomon Islands and other Pacific Islands.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Flores, Carola F , Broitman, Bernardo R
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124664 , vital:35644 , https://doi.10.1007/s11160-014-9376-4
- Description: We examined how human harvesting impacts on managed areas affect the abundance and size distribution of the edible mangrove shellfish Anadara granosa and Polymesoda spp. in the Roviana Lagoon, Solomon Islands. We tested two hypotheses: (1) in areas permanently and temporally closed to human exploitation, abundance and size distribution of these shellfish species is significantly greater than in sites open to exploitation and (2) moderate human disturbance of shell beds, particularly of Polymesoda spp., increases their abundance. Firstly, we studied perceptions of environmental states and processes coupled to foraging and management interventions to assess sociocultural influences on harvesting practices and ascertain the types of management regime that people would consider in a context where poaching and interloping are common practices. Secondly, we compared shellfish abundance and shell size from areas that were permanently protected, temporally reserved for communal harvest, and permanently open for exploitation. Thirdly, drawing from women’s local knowledge, we measured the abundance of Polymesoda spp. in relation to mud compactness in quadrats across the three management regimes. Results showed that both species were significantly more abundant in permanent and temporally closed sites than in open sites. In the mud compactness study, however, while shell abundance was greater in moderately compacted quadrats, there was no statistical relationship between mud compactness and shell abundance within or across the three management regimes. Results suggest that even under the strong impacts of poaching, temporally closed areas have more clams than open areas and are as effective as areas that are permanently closed nominally. The results also suggest that human harvesting regimes can influence the effectiveness of local management decisions and thus are important when designing community-based conservation programs in the Solomon Islands and other Pacific Islands.
- Full Text:
- Date Issued: 2015
Change in Roviana Lagoon Coral Reef ethnobiology:
- Aswani, Shankar, Albert, Simon
- Authors: Aswani, Shankar , Albert, Simon
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145460 , vital:38440 , ISBN 9783319237633 , DOI: 10.1007/978-3-319-23763-3_10
- Description: Coral reefs are iconic for their beauty and biodiversity, and are of great socioeconomic and cultural importance for many coastal communities across the tropics. However, little is known about people’s local classification and their social and ecological relationship with these habitats. This chapter describes Roviana people’s changing ecological and social relationship with their coral reefs, which are increasingly being damaged by humans. First, we combined ecological and social data to describe people’s classification of local coral reefs in tandem with the productive practices conducted in these habitats. Second, we examined local perceptions and recognized effects of environmental and climatic changes on reefs over the last two decades. Finally, we measured changes in fishing activities and in the taxonomic systems (between 1995 and 2011) to evaluate if recent social and economic change has led to the erosion of marine indigenous ecological knowledge and associated practices. Studying people’s changing perceptions of their coral reefs is crucial to understand their ability to identify and adapt to environmental transformations. Simply, the way local people perceive the state of the environment is not only important in terms of changes in local epistemology but also has important implications for how resources are used and managed, and this information can be coupled with scientific one for a broader management strategy.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Albert, Simon
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145460 , vital:38440 , ISBN 9783319237633 , DOI: 10.1007/978-3-319-23763-3_10
- Description: Coral reefs are iconic for their beauty and biodiversity, and are of great socioeconomic and cultural importance for many coastal communities across the tropics. However, little is known about people’s local classification and their social and ecological relationship with these habitats. This chapter describes Roviana people’s changing ecological and social relationship with their coral reefs, which are increasingly being damaged by humans. First, we combined ecological and social data to describe people’s classification of local coral reefs in tandem with the productive practices conducted in these habitats. Second, we examined local perceptions and recognized effects of environmental and climatic changes on reefs over the last two decades. Finally, we measured changes in fishing activities and in the taxonomic systems (between 1995 and 2011) to evaluate if recent social and economic change has led to the erosion of marine indigenous ecological knowledge and associated practices. Studying people’s changing perceptions of their coral reefs is crucial to understand their ability to identify and adapt to environmental transformations. Simply, the way local people perceive the state of the environment is not only important in terms of changes in local epistemology but also has important implications for how resources are used and managed, and this information can be coupled with scientific one for a broader management strategy.
- Full Text:
- Date Issued: 2015