A quantitative post-release evaluation of biological control of water lettuce, Pistia stratiotes L. (Araceae) by the weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae) at Cape Recife Nature Reserve, Eastern Cape Province, South Africa
- Moore, Gareth R, Hill, Martin P
- Authors: Moore, Gareth R , Hill, Martin P
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6839 , http://hdl.handle.net/10962/d1010987 , http://dx.doi.org/10.4001/003.020.0217 , https://orcid.org/0000-0003-0579-5298
- Description: [from the introduction] Water lettuce, Pistia stratiotes L. (Araceae) is recognized as being among the world’s worst aquatic weeds. In its adventive range, the plant forms extensive mats capable of blocking navigation channels, impeding water flow in irrigation and flood control canals, and disrupting hydropower generation (Holm et al. 1977). Dense mats of the weed prevent light penetration into the water column which negatively affects submerged aquatic plant communities, causing a lowering of the oxygen concentration and thereby reducing benthic invertebrate and fish populations (Neuenschwander et al. 2009).
- Full Text:
- Date Issued: 2012
- Authors: Moore, Gareth R , Hill, Martin P
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6839 , http://hdl.handle.net/10962/d1010987 , http://dx.doi.org/10.4001/003.020.0217 , https://orcid.org/0000-0003-0579-5298
- Description: [from the introduction] Water lettuce, Pistia stratiotes L. (Araceae) is recognized as being among the world’s worst aquatic weeds. In its adventive range, the plant forms extensive mats capable of blocking navigation channels, impeding water flow in irrigation and flood control canals, and disrupting hydropower generation (Holm et al. 1977). Dense mats of the weed prevent light penetration into the water column which negatively affects submerged aquatic plant communities, causing a lowering of the oxygen concentration and thereby reducing benthic invertebrate and fish populations (Neuenschwander et al. 2009).
- Full Text:
- Date Issued: 2012
Of ants and cicadas: thinking and doing
- Authors: Villet, Martin H
- Date: 2012
- Language: English
- Type: Text
- Identifier: vital:588 , http://hdl.handle.net/10962/d1018948
- Full Text:
- Date Issued: 2012
- Authors: Villet, Martin H
- Date: 2012
- Language: English
- Type: Text
- Identifier: vital:588 , http://hdl.handle.net/10962/d1018948
- Full Text:
- Date Issued: 2012
The distribution, habitat, diet and forensic significance of the scarab Frankenbergerius forcipatus (Harold, 1881) (Coleoptera : Scarabaeidae)
- Midgley, John M, Collett, I J, Villet, Martin H
- Authors: Midgley, John M , Collett, I J , Villet, Martin H
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6842 , http://hdl.handle.net/10962/d1010992
- Description: Records of African beetles feeding on carrion are scattered and incomplete, but important to forensic entomology. Thirty-three specimens of Frankenbergerius forcipatus (Harold, 1881) were found on carrionnear Grahamstown, Eastern Cape, South Africa, providing new insight into the distribution (hills and mountains), habitat (fynbos and forest), biology (generalist on decaying material) and forensic significance (wet-decay, late opportunist) of the species.
- Full Text:
- Date Issued: 2012
- Authors: Midgley, John M , Collett, I J , Villet, Martin H
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6842 , http://hdl.handle.net/10962/d1010992
- Description: Records of African beetles feeding on carrion are scattered and incomplete, but important to forensic entomology. Thirty-three specimens of Frankenbergerius forcipatus (Harold, 1881) were found on carrionnear Grahamstown, Eastern Cape, South Africa, providing new insight into the distribution (hills and mountains), habitat (fynbos and forest), biology (generalist on decaying material) and forensic significance (wet-decay, late opportunist) of the species.
- Full Text:
- Date Issued: 2012
The NINJA-2 catalog of hybrid post-Newtonian/numerical-relativity waveforms for non-precessing black-hole binaries
- Ajith, P, Boyle, M, Brown, Dane A, Buchman, L T, Pollney, D
- Authors: Ajith, P , Boyle, M , Brown, Dane A , Buchman, L T , Pollney, D
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6788 , http://hdl.handle.net/10962/d1006940
- Description: The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search and parameter-estimation algorithms using numerically generated waveforms, and to foster closer collaboration between the numerical relativity and data analysis communities. The first NINJA project used only a small number of injections of short numerical-relativity waveforms, which limited its ability to draw quantitative conclusions. The goal of the NINJA-2 project is to overcome these limitations with long post-Newtonian - numerical relativity hybrid waveforms, large numbers of injections, and the use of real detector data. We report on the submission requirements for the NINJA-2 project and the construction of the waveform catalog. Eight numerical relativity groups have contributed 63 hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. We summarize the techniques used by each group in constructing their submissions. We also report on the procedures used to validate these submissions, including examination in the time and frequency domains and comparisons of waveforms from different groups against each other. These procedures have so far considered only the $(ell,m)=(2,2)$ mode. Based on these studies we judge that the hybrid waveforms are suitable for NINJA-2 studies. We note some of the plans for these investigations.
- Full Text:
- Date Issued: 2012
- Authors: Ajith, P , Boyle, M , Brown, Dane A , Buchman, L T , Pollney, D
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6788 , http://hdl.handle.net/10962/d1006940
- Description: The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search and parameter-estimation algorithms using numerically generated waveforms, and to foster closer collaboration between the numerical relativity and data analysis communities. The first NINJA project used only a small number of injections of short numerical-relativity waveforms, which limited its ability to draw quantitative conclusions. The goal of the NINJA-2 project is to overcome these limitations with long post-Newtonian - numerical relativity hybrid waveforms, large numbers of injections, and the use of real detector data. We report on the submission requirements for the NINJA-2 project and the construction of the waveform catalog. Eight numerical relativity groups have contributed 63 hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. We summarize the techniques used by each group in constructing their submissions. We also report on the procedures used to validate these submissions, including examination in the time and frequency domains and comparisons of waveforms from different groups against each other. These procedures have so far considered only the $(ell,m)=(2,2)$ mode. Based on these studies we judge that the hybrid waveforms are suitable for NINJA-2 studies. We note some of the plans for these investigations.
- Full Text:
- Date Issued: 2012
Cooperative wasp-killing by mixed-species colonies of honeybees, Apis cerana and Apis mellifera
- Tan, K, Yang, M-Y, Li, H, Zhang, Z-L, Radloff, Sarah E, Hepburn, H Randall
- Authors: Tan, K , Yang, M-Y , Li, H , Zhang, Z-L , Radloff, Sarah E , Hepburn, H Randall
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6838 , http://hdl.handle.net/10962/d1010979 , http://dx.doi.org/10.1007/s13592-011-0098-5
- Description: The cooperative defensive behaviour of mixed-species colonies of honeybees, Apis cerana and Apis mellifera, were tested against a predatory wasp, Vespa velutina. When vespine wasps hawk honeybees at their nest entrances, the difference in the numbers of bees involved in heat-balling among pure species and mixed-species colonies was not significantly different. However, in the mixed colonies, the numbers of A. cerana and A. mellifera workers involved in heat-balling were significantly different. The duration of heat-balling among these three groups was significantly different. During heat-balling, guard bees of both species in mixed colonies raised their thoracic temperatures and the core temperatures of the heat-balls were about 45°C, which is not significantly different from that of the pure species. These results suggest that the two species of honeybees can cooperate in joint heat-balling against the wasps, but A. cerana was more assertive in such defence.
- Full Text: false
- Date Issued: 2012
- Authors: Tan, K , Yang, M-Y , Li, H , Zhang, Z-L , Radloff, Sarah E , Hepburn, H Randall
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6838 , http://hdl.handle.net/10962/d1010979 , http://dx.doi.org/10.1007/s13592-011-0098-5
- Description: The cooperative defensive behaviour of mixed-species colonies of honeybees, Apis cerana and Apis mellifera, were tested against a predatory wasp, Vespa velutina. When vespine wasps hawk honeybees at their nest entrances, the difference in the numbers of bees involved in heat-balling among pure species and mixed-species colonies was not significantly different. However, in the mixed colonies, the numbers of A. cerana and A. mellifera workers involved in heat-balling were significantly different. The duration of heat-balling among these three groups was significantly different. During heat-balling, guard bees of both species in mixed colonies raised their thoracic temperatures and the core temperatures of the heat-balls were about 45°C, which is not significantly different from that of the pure species. These results suggest that the two species of honeybees can cooperate in joint heat-balling against the wasps, but A. cerana was more assertive in such defence.
- Full Text: false
- Date Issued: 2012
Design of realistic hybrid marine resource management programs in Oceania
- Aswani, Shankar, Ruddle, Kenneth
- Authors: Aswani, Shankar , Ruddle, Kenneth
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70615 , vital:29681 , https://doi.org/10.2984/67.3.11
- Description: This review article synthesizes the authors' several decades of multidisciplinary natural and social science and applied marine resource management experience in the Asia-Pacific region to examine the strengthening of coastal and marine resource management and conservation using alliances between local communities and external institutions. The objective is to assist the design of resource management and conservation programs that enhance the capacity of coastal communities in Oceania to confront both diminishing marine resources and the effects of climate change by providing guidelines for protecting marine biodiversity and vulnerable ecosystem functions. This article describes a management framework that hybridizes local beliefs and institutions expressed in customary management (CM) with such modern management concepts as marine protected areas (MPAs) and ecosystem-based management (EBM). Hybrid management accommodates the social, political, economic, and cultural contexts of Oceanic communities and, compared with recent or conventional management approaches, can therefore better address fundamental local concerns such as coastal degradation, climate change, sea level rise, weak governance, corruption, limited resources and staff to manage and monitor marine resources, and increasing poverty. Research on the hybridization of management systems demonstrates opportunities to establish context-appropriate EBM and/or other managerial arrangements that include terrestrial and adjacent coastal-marine ecosystems. Formal and informal CM systems are widespread in Oceania and in some parts of Southeast Asia, and if appropriate strategies are employed rapid progress toward hybrid CM-EBM could be enabled.
- Full Text:
- Date Issued: 2012
- Authors: Aswani, Shankar , Ruddle, Kenneth
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70615 , vital:29681 , https://doi.org/10.2984/67.3.11
- Description: This review article synthesizes the authors' several decades of multidisciplinary natural and social science and applied marine resource management experience in the Asia-Pacific region to examine the strengthening of coastal and marine resource management and conservation using alliances between local communities and external institutions. The objective is to assist the design of resource management and conservation programs that enhance the capacity of coastal communities in Oceania to confront both diminishing marine resources and the effects of climate change by providing guidelines for protecting marine biodiversity and vulnerable ecosystem functions. This article describes a management framework that hybridizes local beliefs and institutions expressed in customary management (CM) with such modern management concepts as marine protected areas (MPAs) and ecosystem-based management (EBM). Hybrid management accommodates the social, political, economic, and cultural contexts of Oceanic communities and, compared with recent or conventional management approaches, can therefore better address fundamental local concerns such as coastal degradation, climate change, sea level rise, weak governance, corruption, limited resources and staff to manage and monitor marine resources, and increasing poverty. Research on the hybridization of management systems demonstrates opportunities to establish context-appropriate EBM and/or other managerial arrangements that include terrestrial and adjacent coastal-marine ecosystems. Formal and informal CM systems are widespread in Oceania and in some parts of Southeast Asia, and if appropriate strategies are employed rapid progress toward hybrid CM-EBM could be enabled.
- Full Text:
- Date Issued: 2012
Spectroscopic and physicochemical behavior of magnesium phthalocyanine derivatives mono-substituted with a carboxylic acid group
- Nombona, Nolwazi, Chidawanyika, Wadzanai J U, Nyokong, Tebello
- Authors: Nombona, Nolwazi , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244450 , vital:51258 , xlink:href="https://doi.org/10.1016/j.molstruc.2011.12.051"
- Description: This work reports on the synthesis of novel unsymmetrically substituted magnesium phthalocyanine complexes containing one carboxyl group. The physicochemical behavior of these complexes were compared with those of their unmetallated and zinc counterparts. The MgPcs showed interesting absorption spectra with [8,15,22-Tris-(naphtho)-4,5-(3-carboxy-1,2-dioxyphenyl)phthalocyaninato]magnesium (II) showing a large split in the Q band whereas [8,15,22-Tris-(naphtho)-2-(carboxy) phthalocyaninato]magnesium(II) presented only a small splitting. The magnesium phthalocyanine derivatives displayed higher fluorescence quantum yields compared to unmetallated and zinc phthalocyanine counterparts. The latter gave admirable triplet and singlet oxygen quantum yields. These molecules can distinctly be employed in the field of photodynamic therapy in combination with fluorescence imaging.
- Full Text:
- Date Issued: 2012
- Authors: Nombona, Nolwazi , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244450 , vital:51258 , xlink:href="https://doi.org/10.1016/j.molstruc.2011.12.051"
- Description: This work reports on the synthesis of novel unsymmetrically substituted magnesium phthalocyanine complexes containing one carboxyl group. The physicochemical behavior of these complexes were compared with those of their unmetallated and zinc counterparts. The MgPcs showed interesting absorption spectra with [8,15,22-Tris-(naphtho)-4,5-(3-carboxy-1,2-dioxyphenyl)phthalocyaninato]magnesium (II) showing a large split in the Q band whereas [8,15,22-Tris-(naphtho)-2-(carboxy) phthalocyaninato]magnesium(II) presented only a small splitting. The magnesium phthalocyanine derivatives displayed higher fluorescence quantum yields compared to unmetallated and zinc phthalocyanine counterparts. The latter gave admirable triplet and singlet oxygen quantum yields. These molecules can distinctly be employed in the field of photodynamic therapy in combination with fluorescence imaging.
- Full Text:
- Date Issued: 2012
Interaction of CdTe quantum dots with 2, 2-diphenyl-1-picrylhydrazyl free radical
- Adegoke, Oluwasesan, Chidawanyika, Wadzanai J U, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245751 , vital:51402 , xlink:href="https://doi.org/10.1007/s10895-011-1012-2"
- Description: The interaction of 2,2-diphenyl-1-picrylhydrazyl (DPPH●) free radical with thiol-capped CdTe quantum dots (QDs) has been studied by UV–vis spectroscopy, steady state and time resolved fluorescence measurements. Addition of DPPH● radical to CdTe QDs resulted in fluorescence quenching. The interaction occurs through static quenching as this was confirmed by fluorescence lifetime measurements. Time course absorption studies indicates that DPPH● may be reduced by interaction with QDs to the substituted hydrazine form (2,2-diphenyl-1-picrylhydrazine) DPPH-H. The mechanism of fluorescence quenching of CdTe QDs by DPPH● is proposed.
- Full Text:
- Date Issued: 2012
- Authors: Adegoke, Oluwasesan , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245751 , vital:51402 , xlink:href="https://doi.org/10.1007/s10895-011-1012-2"
- Description: The interaction of 2,2-diphenyl-1-picrylhydrazyl (DPPH●) free radical with thiol-capped CdTe quantum dots (QDs) has been studied by UV–vis spectroscopy, steady state and time resolved fluorescence measurements. Addition of DPPH● radical to CdTe QDs resulted in fluorescence quenching. The interaction occurs through static quenching as this was confirmed by fluorescence lifetime measurements. Time course absorption studies indicates that DPPH● may be reduced by interaction with QDs to the substituted hydrazine form (2,2-diphenyl-1-picrylhydrazine) DPPH-H. The mechanism of fluorescence quenching of CdTe QDs by DPPH● is proposed.
- Full Text:
- Date Issued: 2012
Effects of patch-size on populations of intertidal limpets, Siphonaria spp., in a linear landscape
- Cole, Victoria J, Johnson, Linda G, McQuaid, Christopher D
- Authors: Cole, Victoria J , Johnson, Linda G , McQuaid, Christopher D
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6845 , http://hdl.handle.net/10962/d1011050
- Description: Organisms with different life-histories and abilities to disperse often utilise habitat patches in different ways. We investigated the influence of the size of patches of rock (separated by stretches of sand) on the density of pulmonate limpets (Siphonaria spp.) along 1500 km of the linear landscape of the South African coastline. We compared the influence of patch-size on two congeneric species with different modes of development, S. serrata a direct developer, and S. concinna a planktonic developer. We tested the spatial and temporal consistency of the effects of patch-size by sampling 7 independent regions spanning the distributional range of both species of limpets, and by sampling one region at monthly intervals for 1 year. Within each region or month, 4 small patches (<20 m in length) interspersed with the 4 large patches (>60 m in length) were sampled. Across the entire geographic range and throughout the year, there were more of both species of limpets in large patches than in small patches. In most regions, there was greater variability in large patches than small patches. Variability within patches in a single region was similar throughout the year, with greater variability of both species in large than in small patches. We found little influence of the mode of development on the response of limpets to patch-size. Our findings highlight the importance of understanding patterns of distribution of species with respect to habitat heterogeneity in linear landscapes, and contradict the idea that organism mobility at an early ontogenetic stage directly affects habitat use.
- Full Text:
- Date Issued: 2012
- Authors: Cole, Victoria J , Johnson, Linda G , McQuaid, Christopher D
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6845 , http://hdl.handle.net/10962/d1011050
- Description: Organisms with different life-histories and abilities to disperse often utilise habitat patches in different ways. We investigated the influence of the size of patches of rock (separated by stretches of sand) on the density of pulmonate limpets (Siphonaria spp.) along 1500 km of the linear landscape of the South African coastline. We compared the influence of patch-size on two congeneric species with different modes of development, S. serrata a direct developer, and S. concinna a planktonic developer. We tested the spatial and temporal consistency of the effects of patch-size by sampling 7 independent regions spanning the distributional range of both species of limpets, and by sampling one region at monthly intervals for 1 year. Within each region or month, 4 small patches (<20 m in length) interspersed with the 4 large patches (>60 m in length) were sampled. Across the entire geographic range and throughout the year, there were more of both species of limpets in large patches than in small patches. In most regions, there was greater variability in large patches than small patches. Variability within patches in a single region was similar throughout the year, with greater variability of both species in large than in small patches. We found little influence of the mode of development on the response of limpets to patch-size. Our findings highlight the importance of understanding patterns of distribution of species with respect to habitat heterogeneity in linear landscapes, and contradict the idea that organism mobility at an early ontogenetic stage directly affects habitat use.
- Full Text:
- Date Issued: 2012
Love thy neighbour : group properties of gaping behaviour in mussel aggregations
- Nicastro, Katy R, Zardi, Gerardo I, McQuaid, Christopher D, Pearson, Gareth A, Serrão, Ester A
- Authors: Nicastro, Katy R , Zardi, Gerardo I , McQuaid, Christopher D , Pearson, Gareth A , Serrão, Ester A
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6841 , http://hdl.handle.net/10962/d1010991
- Description: By associating closely with others to form a group, an animal can benefit from a number of advantages including reduced risk of predation, amelioration of environmental conditions, and increased reproductive success, but at the price of reduced resources. Although made up of individual members, an aggregation often displays novel effects that do not manifest at the level of the individual organism. Here we show that very simple behaviour in intertidal mussels shows new effects in dense aggregations but not in isolated individuals. Perna perna and Mytilus galloprovincialis are gaping (periodic valve movement during emersion) and non-gaping mussels respectively. P. perna gaping behaviour had no effect on body temperatures of isolated individuals, while it led to increased humidity and decreased temperatures in dense groups (beds). Gaping resulted in cooler body temperatures for P. perna than M. galloprovincialis when in aggregations, while solitary individuals exhibited the highest temperatures. Gradients of increasing body temperature were detected from the center to edges of beds, but M. galloprovincialis at the edge had the same temperature as isolated individuals. Furthermore, a field study showed that during periods of severe heat stress, mortality rates of mussels within beds of the gaping P. perna were lower than those of isolated individuals or within beds of M. galloprovincialis, highlighting the determinant role of gaping on fitness and group functioning. We demonstrate that new effects of very simple individual behaviour lead to amelioration of abiotic conditions at the aggregation level and that these effects increase mussel resistance to thermal stress.
- Full Text:
- Date Issued: 2012
- Authors: Nicastro, Katy R , Zardi, Gerardo I , McQuaid, Christopher D , Pearson, Gareth A , Serrão, Ester A
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6841 , http://hdl.handle.net/10962/d1010991
- Description: By associating closely with others to form a group, an animal can benefit from a number of advantages including reduced risk of predation, amelioration of environmental conditions, and increased reproductive success, but at the price of reduced resources. Although made up of individual members, an aggregation often displays novel effects that do not manifest at the level of the individual organism. Here we show that very simple behaviour in intertidal mussels shows new effects in dense aggregations but not in isolated individuals. Perna perna and Mytilus galloprovincialis are gaping (periodic valve movement during emersion) and non-gaping mussels respectively. P. perna gaping behaviour had no effect on body temperatures of isolated individuals, while it led to increased humidity and decreased temperatures in dense groups (beds). Gaping resulted in cooler body temperatures for P. perna than M. galloprovincialis when in aggregations, while solitary individuals exhibited the highest temperatures. Gradients of increasing body temperature were detected from the center to edges of beds, but M. galloprovincialis at the edge had the same temperature as isolated individuals. Furthermore, a field study showed that during periods of severe heat stress, mortality rates of mussels within beds of the gaping P. perna were lower than those of isolated individuals or within beds of M. galloprovincialis, highlighting the determinant role of gaping on fitness and group functioning. We demonstrate that new effects of very simple individual behaviour lead to amelioration of abiotic conditions at the aggregation level and that these effects increase mussel resistance to thermal stress.
- Full Text:
- Date Issued: 2012
Differential regulation of monocyte cytokine release by αV and β2 integrins that bind CD23:
- Edkins, Adrienne L, Borland, Gillian, Acharya, Mridu, Cogdell, Richard, Ozanne, Bradford W, Cushley, William
- Authors: Edkins, Adrienne L , Borland, Gillian , Acharya, Mridu , Cogdell, Richard , Ozanne, Bradford W , Cushley, William
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165153 , vital:41213 , DOI: 10.1111/j.1365-2567.2012.03576.x
- Description: The human soluble CD23 (sCD23) protein displays highly pleiotropic cytokine‐like activity. Monocytic cells express the sCD23‐binding integrins αVβ3, αVβ5, αMβ2 and αXβ2, but it is unclear which of these four integrins most acutely regulates sCD23‐driven cytokine release. The hypothesis that ligation of different sCD23‐binding integrins promoted release of distinct subsets of cytokines was tested. Lipopolysaccharide (LPS) and sCD23 promoted release of distinct groups of cytokines from the THP‐1 model cell line.
- Full Text:
- Date Issued: 2012
- Authors: Edkins, Adrienne L , Borland, Gillian , Acharya, Mridu , Cogdell, Richard , Ozanne, Bradford W , Cushley, William
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165153 , vital:41213 , DOI: 10.1111/j.1365-2567.2012.03576.x
- Description: The human soluble CD23 (sCD23) protein displays highly pleiotropic cytokine‐like activity. Monocytic cells express the sCD23‐binding integrins αVβ3, αVβ5, αMβ2 and αXβ2, but it is unclear which of these four integrins most acutely regulates sCD23‐driven cytokine release. The hypothesis that ligation of different sCD23‐binding integrins promoted release of distinct subsets of cytokines was tested. Lipopolysaccharide (LPS) and sCD23 promoted release of distinct groups of cytokines from the THP‐1 model cell line.
- Full Text:
- Date Issued: 2012
Microbial monitoring of surface water in South Africa: an overview
- Luyt, Catherine D, Tandlich, Roman, Muller, Wilhelmine J, Wilhelmi, Brendan S
- Authors: Luyt, Catherine D , Tandlich, Roman , Muller, Wilhelmine J , Wilhelmi, Brendan S
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71636 , vital:29927 , https://doi.org/10.3390/ijerph9082669
- Description: Infrastructural problems force South African households to supplement their drinking water consumption from water resources of inadequate microbial quality. Microbial water quality monitoring is currently based on the Colilert®18 system which leads to rapidly available results. Using Escherichia coli as the indicator microorganism limits the influence of environmental sources on the reported results. The current system allows for understanding of long-term trends of microbial surface water quality and the related public health risks. However, rates of false positive for the Colilert®18-derived concentrations have been reported to range from 7.4% to 36.4%. At the same time, rates of false negative results vary from 3.5% to 12.5%; and the Colilert medium has been reported to provide for cultivation of only 56.8% of relevant strains. Identification of unknown sources of faecal contamination is not currently feasible. Based on literature review, calibration of the antibiotic-resistance spectra of Escherichia coli or the bifidobacterial tracking ratio should be investigated locally for potential implementation into the existing monitoring system. The current system could be too costly to implement in certain areas of South Africa where the modified H2S strip test might be used as a surrogate for the Colilert®18.
- Full Text:
- Date Issued: 2012
- Authors: Luyt, Catherine D , Tandlich, Roman , Muller, Wilhelmine J , Wilhelmi, Brendan S
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71636 , vital:29927 , https://doi.org/10.3390/ijerph9082669
- Description: Infrastructural problems force South African households to supplement their drinking water consumption from water resources of inadequate microbial quality. Microbial water quality monitoring is currently based on the Colilert®18 system which leads to rapidly available results. Using Escherichia coli as the indicator microorganism limits the influence of environmental sources on the reported results. The current system allows for understanding of long-term trends of microbial surface water quality and the related public health risks. However, rates of false positive for the Colilert®18-derived concentrations have been reported to range from 7.4% to 36.4%. At the same time, rates of false negative results vary from 3.5% to 12.5%; and the Colilert medium has been reported to provide for cultivation of only 56.8% of relevant strains. Identification of unknown sources of faecal contamination is not currently feasible. Based on literature review, calibration of the antibiotic-resistance spectra of Escherichia coli or the bifidobacterial tracking ratio should be investigated locally for potential implementation into the existing monitoring system. The current system could be too costly to implement in certain areas of South Africa where the modified H2S strip test might be used as a surrogate for the Colilert®18.
- Full Text:
- Date Issued: 2012
'God is my forest': Xhosa cultural values provide untapped opportunities for conservation
- Cocks, Michelle L, Dold, Anthony P, Vetter, Susan M
- Authors: Cocks, Michelle L , Dold, Anthony P , Vetter, Susan M
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141198 , vital:37952 , DOI: 10.4102/sajs.v108i5/6.880
- Description: In South Africa conservation is still largely framed in terms of Western scientific values, with a focus on material benefits to local communities, whilst little is known about the intangible values local people attach to nature and biodiversity. We explored the cultural, spiritual and emotional relationships with nature expressed by Xhosa people, within the MaputalandPondoland-Albany Hotspot, as well as the activities that mediate this relationship. A descriptive research approach was applied to document the emotions, meanings and values associated with landscape elements. This approach included group and individual interviews and ‘walk-in-the-woods’ interviews and participatory mapping exercises. Respondents portrayed a strong, although not always easily articulated, appreciation for nature, especially ihlathi lesiXhosa (‘Xhosa forest’, vegetation types within the Thicket Biome).
- Full Text:
- Date Issued: 2012
- Authors: Cocks, Michelle L , Dold, Anthony P , Vetter, Susan M
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141198 , vital:37952 , DOI: 10.4102/sajs.v108i5/6.880
- Description: In South Africa conservation is still largely framed in terms of Western scientific values, with a focus on material benefits to local communities, whilst little is known about the intangible values local people attach to nature and biodiversity. We explored the cultural, spiritual and emotional relationships with nature expressed by Xhosa people, within the MaputalandPondoland-Albany Hotspot, as well as the activities that mediate this relationship. A descriptive research approach was applied to document the emotions, meanings and values associated with landscape elements. This approach included group and individual interviews and ‘walk-in-the-woods’ interviews and participatory mapping exercises. Respondents portrayed a strong, although not always easily articulated, appreciation for nature, especially ihlathi lesiXhosa (‘Xhosa forest’, vegetation types within the Thicket Biome).
- Full Text:
- Date Issued: 2012
A new broom sweeps clean: the economic and cultural value of grass brooms in the Eastern Cape Province, South Africa
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141382 , vital:37967 , DOI: 10.1080/14728028.2004.9752477
- Description: In southern Africa over the last twenty years, much attention has been given to the importance of NTFPs for rural livelihoods through their household consumption and sale. They have been classified as having either subsistence consumption or commercial values. These values are mostly related to their utilitarian functions, but recent studies show that NTFPs also hold strong cultural functions. Such cultural functions can play a role in both rural and urban livelihoods; consequently the values of NTFPs may be related to both utilitarian and cultural functions. This paper demonstrates the cultural functions of grass brooms in urban areas in South Africa and the impact of their trade on income generation in rural areas, and discusses the concept of culture as a significant factor in the understanding of the role of NTFPs in livelihoods, and their values.
- Full Text:
- Date Issued: 2012
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141382 , vital:37967 , DOI: 10.1080/14728028.2004.9752477
- Description: In southern Africa over the last twenty years, much attention has been given to the importance of NTFPs for rural livelihoods through their household consumption and sale. They have been classified as having either subsistence consumption or commercial values. These values are mostly related to their utilitarian functions, but recent studies show that NTFPs also hold strong cultural functions. Such cultural functions can play a role in both rural and urban livelihoods; consequently the values of NTFPs may be related to both utilitarian and cultural functions. This paper demonstrates the cultural functions of grass brooms in urban areas in South Africa and the impact of their trade on income generation in rural areas, and discusses the concept of culture as a significant factor in the understanding of the role of NTFPs in livelihoods, and their values.
- Full Text:
- Date Issued: 2012
Large pollen loads of a South African asclepiad do not interfere with the foraging behaviour or efficiency of pollinating honey bees
- Coombs, Gareth, Dold, Anthony P, Brassine, Eleanor I, Peter, Craig I
- Authors: Coombs, Gareth , Dold, Anthony P , Brassine, Eleanor I , Peter, Craig I
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6509 , http://hdl.handle.net/10962/d1005936
- Description: The pollen of asclepiads (Asclepiadoideae, Apocynaceae) and most orchids (Orchidaceae) are packaged as large aggregations known as pollinaria that are removed as entire units by pollinators. In some instances, individual pollinators may accumulate large loads of these pollinaria. We found that the primary pollinator of Cynanchum ellipticum (Apocynaceae-Asclepiadoideae), the honey bee Apis mellifera, accumulate very large agglomerations of pollinaria on their mouthparts when foraging on this species. We tested whether large pollinarium loads negatively affected the foraging behaviour and foraging efficiency of honey bees by slowing foraging speeds or causing honey bees to visit fewer flowers, and found no evidence to suggest that large pollinarium loads altered foraging behaviour. C. ellipticum displayed consistently high levels of pollination success and pollen transfer efficiency (PTE). This may be a consequence of efficiently loading large numbers of pollinaria onto pollinators even when primary points of attachment on pollinators are already occupied and doing so in a manner that does not impact the foraging behaviour of pollinating insects.
- Full Text:
- Date Issued: 2012
- Authors: Coombs, Gareth , Dold, Anthony P , Brassine, Eleanor I , Peter, Craig I
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6509 , http://hdl.handle.net/10962/d1005936
- Description: The pollen of asclepiads (Asclepiadoideae, Apocynaceae) and most orchids (Orchidaceae) are packaged as large aggregations known as pollinaria that are removed as entire units by pollinators. In some instances, individual pollinators may accumulate large loads of these pollinaria. We found that the primary pollinator of Cynanchum ellipticum (Apocynaceae-Asclepiadoideae), the honey bee Apis mellifera, accumulate very large agglomerations of pollinaria on their mouthparts when foraging on this species. We tested whether large pollinarium loads negatively affected the foraging behaviour and foraging efficiency of honey bees by slowing foraging speeds or causing honey bees to visit fewer flowers, and found no evidence to suggest that large pollinarium loads altered foraging behaviour. C. ellipticum displayed consistently high levels of pollination success and pollen transfer efficiency (PTE). This may be a consequence of efficiently loading large numbers of pollinaria onto pollinators even when primary points of attachment on pollinators are already occupied and doing so in a manner that does not impact the foraging behaviour of pollinating insects.
- Full Text:
- Date Issued: 2012
Exploring the influence of mindfulness-based stress reduction (MBSR) programmes on participants experience of time, particularly the present (here and now): a case study of Eastern Cape participants
- Authors: Schofield, Lorna
- Date: 2012
- Subjects: Acceptance and commitment therapy , Stress management , Depression, Mental -- Treatment
- Language: English
- Type: Thesis , Masters , M Soc Sc (C Psy)
- Identifier: vital:11611 , http://hdl.handle.net/10353/d1005640
- Description: This study aims to explore the extent to which participating in a Mindfulness-Based Stress Reduction (MBSR) programme may result in shifts in people’s relationship with time, notably whether they become more present-focussed. The eight week MBSR programme advocates mindfulness, which is defined as paying attention on purpose in the present moment without judgement, as a way of reducing stress. The programme has been available in East London since 2009. A case study of eight MBSR programme participants’ experiences using narrative analysis was conducted. Narrative psychology and social constructionism provided the theoretical basis in which our storied lives are located in culturally inscribed narratives, with specific discourses around time and stress. Time discourses tend to pressurise people to believe that it is better to go about daily life at a fast pace, which requires significant hurrying and rushing with pervasive senses of time urgency. Stress discourse locates stress management within individuals. One-on-one semi structured interviews were held so that participants could reflect on their experience of time and the present moment orientation of the programme. Participants’ perceived a shift in how they experienced time with greater awareness of being present-focussed and they identified stress reduction benefits, which included feeling calmer, less panicked and more self-accepting. However, some of the participants maintaining the formal mindfulness practices like the body scan, meditation and mindful movement after the programme often proved difficult, as they were drawn back into their dominant narratives around time which were characterised by busyness, productivity and time scarcity.
- Full Text:
- Date Issued: 2012
- Authors: Schofield, Lorna
- Date: 2012
- Subjects: Acceptance and commitment therapy , Stress management , Depression, Mental -- Treatment
- Language: English
- Type: Thesis , Masters , M Soc Sc (C Psy)
- Identifier: vital:11611 , http://hdl.handle.net/10353/d1005640
- Description: This study aims to explore the extent to which participating in a Mindfulness-Based Stress Reduction (MBSR) programme may result in shifts in people’s relationship with time, notably whether they become more present-focussed. The eight week MBSR programme advocates mindfulness, which is defined as paying attention on purpose in the present moment without judgement, as a way of reducing stress. The programme has been available in East London since 2009. A case study of eight MBSR programme participants’ experiences using narrative analysis was conducted. Narrative psychology and social constructionism provided the theoretical basis in which our storied lives are located in culturally inscribed narratives, with specific discourses around time and stress. Time discourses tend to pressurise people to believe that it is better to go about daily life at a fast pace, which requires significant hurrying and rushing with pervasive senses of time urgency. Stress discourse locates stress management within individuals. One-on-one semi structured interviews were held so that participants could reflect on their experience of time and the present moment orientation of the programme. Participants’ perceived a shift in how they experienced time with greater awareness of being present-focussed and they identified stress reduction benefits, which included feeling calmer, less panicked and more self-accepting. However, some of the participants maintaining the formal mindfulness practices like the body scan, meditation and mindful movement after the programme often proved difficult, as they were drawn back into their dominant narratives around time which were characterised by busyness, productivity and time scarcity.
- Full Text:
- Date Issued: 2012
Mitochondrial DNA paradox: sex-specific genetic structure in a marine mussel despite maternal inheritance and passive dispersal
- Teske, Peter R, Papadopoulos, Isabelle, Barker, Nigel P, McQuaid, Christopher D
- Authors: Teske, Peter R , Papadopoulos, Isabelle , Barker, Nigel P , McQuaid, Christopher D
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6836 , http://hdl.handle.net/10962/d1010959
- Description: Background: When genetic structure is identified using mitochondrial DNA (mtDNA), but no structure is identified using biparentally-inherited nuclear DNA, the discordance is often attributed to differences in dispersal potential between the sexes. Results: We sampled the intertidal rocky shore mussel Perna perna in a South African bay and along the nearby open coast, and sequenced maternally-inherited mtDNA (there is no evidence for paternally-inherited mtDNA in this species) and a biparentally-inherited marker. By treating males and females as different populations, we identified significant genetic structure on the basis of mtDNA data in the females only. Conclusions: This is the first study to report sex-specific differences in genetic structure based on matrilineally-inherited mtDNA in a passively dispersing species that lacks social structure or sexual dimorphism. The observed pattern most likely stems from females being more vulnerable to selection in habitats from which they did not originate, which also manifests itself in a male-biased sex ratio. Our results have three important implications for the interpretation of population genetic data. First, even when mtDNA is inherited exclusively in the female line, it also contains information about males. For that reason, using it to identify sex-specific differences in genetic structure by contrasting it with biparentally-inherited markers is problematic. Second, the fact that sex-specific differences were found in a passively dispersing species in which sex-biased dispersal is unlikely highlights the fact that significant genetic structure is not necessarily a function of low dispersal potential or physical barriers. Third, even though mtDNA is typically used to study historical demographic processes, it also contains information about contemporary processes. Higher survival rates of males in non-native habitats can erase the genetic structure present in their mothers within a single generation.
- Full Text:
- Date Issued: 2012
- Authors: Teske, Peter R , Papadopoulos, Isabelle , Barker, Nigel P , McQuaid, Christopher D
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6836 , http://hdl.handle.net/10962/d1010959
- Description: Background: When genetic structure is identified using mitochondrial DNA (mtDNA), but no structure is identified using biparentally-inherited nuclear DNA, the discordance is often attributed to differences in dispersal potential between the sexes. Results: We sampled the intertidal rocky shore mussel Perna perna in a South African bay and along the nearby open coast, and sequenced maternally-inherited mtDNA (there is no evidence for paternally-inherited mtDNA in this species) and a biparentally-inherited marker. By treating males and females as different populations, we identified significant genetic structure on the basis of mtDNA data in the females only. Conclusions: This is the first study to report sex-specific differences in genetic structure based on matrilineally-inherited mtDNA in a passively dispersing species that lacks social structure or sexual dimorphism. The observed pattern most likely stems from females being more vulnerable to selection in habitats from which they did not originate, which also manifests itself in a male-biased sex ratio. Our results have three important implications for the interpretation of population genetic data. First, even when mtDNA is inherited exclusively in the female line, it also contains information about males. For that reason, using it to identify sex-specific differences in genetic structure by contrasting it with biparentally-inherited markers is problematic. Second, the fact that sex-specific differences were found in a passively dispersing species in which sex-biased dispersal is unlikely highlights the fact that significant genetic structure is not necessarily a function of low dispersal potential or physical barriers. Third, even though mtDNA is typically used to study historical demographic processes, it also contains information about contemporary processes. Higher survival rates of males in non-native habitats can erase the genetic structure present in their mothers within a single generation.
- Full Text:
- Date Issued: 2012
Voices from the forest: celebrating nature and culture in Xhosaland
- Dold, Anthony P, Cocks, Michelle L
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141427 , vital:37971 , ISBN 9781431402991 , https://www.amazon.com/Voices-Forest-Celebrating-Culture-Xhosaland/dp/1431402990
- Description: The link between people and nature is explored in this fascinating book, revealing how plants, animals, and landscapes are profoundly reflected in South Africa’s Xhosa language, stories, poetry, religious rituals, healing practices, and everyday customs. While the South African landscape has for centuries been molded and manipulated by humans, the country and its plants and animals have in turn influenced South Africans’ cultural and spiritual development. Based on 10 years of research, it consists of unique photographs that portray how both contemporary rural and urban South Africans still find great value in nature. A fresh, positive approach to biodiversity conservation, this volume serves as a guide to sustainable practices in the future.
- Full Text:
- Date Issued: 2012
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141427 , vital:37971 , ISBN 9781431402991 , https://www.amazon.com/Voices-Forest-Celebrating-Culture-Xhosaland/dp/1431402990
- Description: The link between people and nature is explored in this fascinating book, revealing how plants, animals, and landscapes are profoundly reflected in South Africa’s Xhosa language, stories, poetry, religious rituals, healing practices, and everyday customs. While the South African landscape has for centuries been molded and manipulated by humans, the country and its plants and animals have in turn influenced South Africans’ cultural and spiritual development. Based on 10 years of research, it consists of unique photographs that portray how both contemporary rural and urban South Africans still find great value in nature. A fresh, positive approach to biodiversity conservation, this volume serves as a guide to sustainable practices in the future.
- Full Text:
- Date Issued: 2012
Perceptions and values of local landscapes: implications for the conservation of biocultural diversity and intangible heritage
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141442 , vital:37972 , ISBN 9789086867493 , DOI: 10.3920/978-90-8686-749-3_10
- Description: South Africa is widely recognised as a highly diverse country with regard to its people, culture, landscapes, biological resources and ecology. The importance of policies on protecting cultural diversity and how they relate to the environment is only just emerging at an international level, but in South African we find there is a complete lack of institutional support for rural communities’ attachment to local landscapes. The main objective of this case study is to improve our understanding of the meanings and values that Xhosa people (amaXhosa) of the Eastern Cape Province of South Africa attach to their natural landscapes. It is clear that the amaXhosa are still intrinsically connected to their natural environment, in particular the thicket biome that is called ihlathi yesiXhosa (Xhosa forest). Access to places and spaces within the natural environment provides a sense of wellbeing, a link to ancestral spirits, a location for religious rituals, plus a wealth of culturallyinspired uses of specific species and sacred places in the landscape. We suggest that local cultural values could be incorporated into the formal conservation process.
- Full Text:
- Date Issued: 2012
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141442 , vital:37972 , ISBN 9789086867493 , DOI: 10.3920/978-90-8686-749-3_10
- Description: South Africa is widely recognised as a highly diverse country with regard to its people, culture, landscapes, biological resources and ecology. The importance of policies on protecting cultural diversity and how they relate to the environment is only just emerging at an international level, but in South African we find there is a complete lack of institutional support for rural communities’ attachment to local landscapes. The main objective of this case study is to improve our understanding of the meanings and values that Xhosa people (amaXhosa) of the Eastern Cape Province of South Africa attach to their natural landscapes. It is clear that the amaXhosa are still intrinsically connected to their natural environment, in particular the thicket biome that is called ihlathi yesiXhosa (Xhosa forest). Access to places and spaces within the natural environment provides a sense of wellbeing, a link to ancestral spirits, a location for religious rituals, plus a wealth of culturallyinspired uses of specific species and sacred places in the landscape. We suggest that local cultural values could be incorporated into the formal conservation process.
- Full Text:
- Date Issued: 2012
A structural and functional specification of a SCIM for service interaction management and personalisation in the IMS
- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2012
- Subjects: Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4606 , http://hdl.handle.net/10962/d1004864 , Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Description: The Internet Protocol Multimedia Subsystem (IMS) is a component of the 3G mobile network that has been specified by standards development organisations such as the 3GPP (3rd Generation Partnership Project) and ETSI (European Telecommunication Standards Institute). IMS seeks to guarantee that the telecommunication network of the future provides subscribers with seamless access to services across disparate networks. In order to achieve this, it defines a service architecture that hosts application servers that provide subscribers with value added services. Typically, an application server bundles all the functionality it needs to execute the services it delivers, however this view is currently being challenged. It is now thought that services should be synthesised from simple building blocks called service capabilities. This decomposition would facilitate the re-use of service capabilities across multiple services and would support the creation of new services that could not have originally been conceived. The shift from monolithic services to those built from service capabilities poses a challenge to the current service model in IMS. To accommodate this, the 3GPP has defined an entity known as a service capability interaction manager (SCIM) that would be responsible for managing the interactions between service capabilities in order to realise complex services. Some of these interactions could potentially lead to undesirable results, which the SCIM must work to avoid. As an added requirement, it is believed that the network should allow policies to be applied to network services which the SCIM should be responsible for enforcing. At the time of writing, the functional and structural architecture of the SCIM has not yet been standardised. This thesis explores the current serv ice architecture of the IMS in detail. Proposals that address the structure and functions of the SCIM are carefully compared and contrasted. This investigation leads to the presentation of key aspects of the SCIM, and provides solutions that explain how it should interact with service capabilities, manage undesirable interactions and factor user and network operator policies into its execution model. A modified design of the IMS service layer that embeds the SCIM is subsequently presented and described. The design uses existing IMS protocols and requires no change in the behaviour of the standard IMS entities. In order to develop a testbed for experimental verification of the design, the identification of suitable software platforms was required. This thesis presents some of the most popular platforms currently used by developers such as the Open IMS Core and OpenSER, as well as an open source, Java-based, multimedia communication platform called Mobicents. As a precursor to the development of the SCIM, a converged multimedia service is presented that describes how a video streaming application that is leveraged by a web portal was implemented for an IMS testbed using Mobicents components. The Mobicents SIP Servlets container was subsequently used to model an initial prototype of the SCIM, using a mUlti-component telephony service to illustrate the proposed service execution model. The design focuses on SIP-based services only, but should also work for other types of IMS application servers as well.
- Full Text:
- Date Issued: 2012
- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2012
- Subjects: Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4606 , http://hdl.handle.net/10962/d1004864 , Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Description: The Internet Protocol Multimedia Subsystem (IMS) is a component of the 3G mobile network that has been specified by standards development organisations such as the 3GPP (3rd Generation Partnership Project) and ETSI (European Telecommunication Standards Institute). IMS seeks to guarantee that the telecommunication network of the future provides subscribers with seamless access to services across disparate networks. In order to achieve this, it defines a service architecture that hosts application servers that provide subscribers with value added services. Typically, an application server bundles all the functionality it needs to execute the services it delivers, however this view is currently being challenged. It is now thought that services should be synthesised from simple building blocks called service capabilities. This decomposition would facilitate the re-use of service capabilities across multiple services and would support the creation of new services that could not have originally been conceived. The shift from monolithic services to those built from service capabilities poses a challenge to the current service model in IMS. To accommodate this, the 3GPP has defined an entity known as a service capability interaction manager (SCIM) that would be responsible for managing the interactions between service capabilities in order to realise complex services. Some of these interactions could potentially lead to undesirable results, which the SCIM must work to avoid. As an added requirement, it is believed that the network should allow policies to be applied to network services which the SCIM should be responsible for enforcing. At the time of writing, the functional and structural architecture of the SCIM has not yet been standardised. This thesis explores the current serv ice architecture of the IMS in detail. Proposals that address the structure and functions of the SCIM are carefully compared and contrasted. This investigation leads to the presentation of key aspects of the SCIM, and provides solutions that explain how it should interact with service capabilities, manage undesirable interactions and factor user and network operator policies into its execution model. A modified design of the IMS service layer that embeds the SCIM is subsequently presented and described. The design uses existing IMS protocols and requires no change in the behaviour of the standard IMS entities. In order to develop a testbed for experimental verification of the design, the identification of suitable software platforms was required. This thesis presents some of the most popular platforms currently used by developers such as the Open IMS Core and OpenSER, as well as an open source, Java-based, multimedia communication platform called Mobicents. As a precursor to the development of the SCIM, a converged multimedia service is presented that describes how a video streaming application that is leveraged by a web portal was implemented for an IMS testbed using Mobicents components. The Mobicents SIP Servlets container was subsequently used to model an initial prototype of the SCIM, using a mUlti-component telephony service to illustrate the proposed service execution model. The design focuses on SIP-based services only, but should also work for other types of IMS application servers as well.
- Full Text:
- Date Issued: 2012