Multiple benefits and values of trees in urban landscapes in two towns in northern South Africa
- Shackleton, Sheona E, Chinyimba, Abby, Hebinck, Paul, Shackleton, Charlie M, Kaoma, Humphrey
- Authors: Shackleton, Sheona E , Chinyimba, Abby , Hebinck, Paul , Shackleton, Charlie M , Kaoma, Humphrey
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180874 , vital:43658 , xlink:href="https://doi.org/10.1016/j.landurbplan.2014.12.004"
- Description: Cities and towns can be conceptualised as complex social-ecological systems or landscapes that are composed of different spatial elements. Trees in urban landscapes provide a variety of tangible and intangible benefits (ecosystem services) that may be valued differently across diverse households and individuals. Here, we consider how the benefits and values of trees to urban residents vary across public and private spaces in three low income neighbourhoods in two medium-sized towns in northern South Africa. We find that the most asset poor residents in informal settlements derive significant benefits from the provisioning services offered by trees in natural green spaces on the ‘urban periphery’; in particular they value supplies of wood for energy, whilst also recognising the importance of regulating services such as shade. Trees in such spaces help these immigrants cope with a lack of infrastructure, services and disposable income after their move to the city. In new, low-cost housing neighbourhoods, the importance of trees in providing shade and shelter in gardens is emphasised due to the hot and dusty nature of these settlements, while residents in older township neighbourhoods make more mention of the aesthetic value of trees in private spaces as well as the fruits they provide. In all neighbourhoods, attitudes towards trees in public spaces were mixed because of their perceived association with crime, although low income households did make extensive use of tree products from natural areas. The relevance of the results for urban planning and greening in low income areas is discussed.
- Full Text:
- Date Issued: 2015
- Authors: Shackleton, Sheona E , Chinyimba, Abby , Hebinck, Paul , Shackleton, Charlie M , Kaoma, Humphrey
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180874 , vital:43658 , xlink:href="https://doi.org/10.1016/j.landurbplan.2014.12.004"
- Description: Cities and towns can be conceptualised as complex social-ecological systems or landscapes that are composed of different spatial elements. Trees in urban landscapes provide a variety of tangible and intangible benefits (ecosystem services) that may be valued differently across diverse households and individuals. Here, we consider how the benefits and values of trees to urban residents vary across public and private spaces in three low income neighbourhoods in two medium-sized towns in northern South Africa. We find that the most asset poor residents in informal settlements derive significant benefits from the provisioning services offered by trees in natural green spaces on the ‘urban periphery’; in particular they value supplies of wood for energy, whilst also recognising the importance of regulating services such as shade. Trees in such spaces help these immigrants cope with a lack of infrastructure, services and disposable income after their move to the city. In new, low-cost housing neighbourhoods, the importance of trees in providing shade and shelter in gardens is emphasised due to the hot and dusty nature of these settlements, while residents in older township neighbourhoods make more mention of the aesthetic value of trees in private spaces as well as the fruits they provide. In all neighbourhoods, attitudes towards trees in public spaces were mixed because of their perceived association with crime, although low income households did make extensive use of tree products from natural areas. The relevance of the results for urban planning and greening in low income areas is discussed.
- Full Text:
- Date Issued: 2015
Multiple femininities in a'single sex'school: re-orienting Life Orientation to learner lifeworlds
- Mthatyana, Andisiwe, Vincent, Louise
- Authors: Mthatyana, Andisiwe , Vincent, Louise
- Date: 2015
- Language: English
- Type: text , article
- Identifier: vital:38019 , http://hdl.handle.net/11660/3689
- Description: Life Orientation sexuality education in South Africa faces many pedagogical challenges, not least among which is that it is sometimes perceived as irrelevant to learners' real interests and concerns. Learners report that the content is repetitive and that they learn more from peers than from the reiterated lessons of risk and disease avoidance that permeate sex education messages. In this article we describe the world of the study site - a 'single sex' school - as consisting of diverse informal student sexual cultures in which repertoires for the development of learner sexual identities are developed, negotiated and transmitted. The study is based on detailed ethnographic immersion in the study site which generated rich data drawn from in-depth interviews, focus groups, observations and solicited narratives. We argue that even the enlightened, tolerant 'best practice' form of sexuality education that takes place at the study site fails to take diverse learner identities, lifeworlds and experiences seriously as a pedagogic starting point, but rather tends to homogenise learners and to impose on them what they need to learn. A more empowering form of sexuality education would take seriously how young people understand themselves as sexual subjects located in unequal ('raced' and classed) social contexts.
- Full Text:
- Date Issued: 2015
- Authors: Mthatyana, Andisiwe , Vincent, Louise
- Date: 2015
- Language: English
- Type: text , article
- Identifier: vital:38019 , http://hdl.handle.net/11660/3689
- Description: Life Orientation sexuality education in South Africa faces many pedagogical challenges, not least among which is that it is sometimes perceived as irrelevant to learners' real interests and concerns. Learners report that the content is repetitive and that they learn more from peers than from the reiterated lessons of risk and disease avoidance that permeate sex education messages. In this article we describe the world of the study site - a 'single sex' school - as consisting of diverse informal student sexual cultures in which repertoires for the development of learner sexual identities are developed, negotiated and transmitted. The study is based on detailed ethnographic immersion in the study site which generated rich data drawn from in-depth interviews, focus groups, observations and solicited narratives. We argue that even the enlightened, tolerant 'best practice' form of sexuality education that takes place at the study site fails to take diverse learner identities, lifeworlds and experiences seriously as a pedagogic starting point, but rather tends to homogenise learners and to impose on them what they need to learn. A more empowering form of sexuality education would take seriously how young people understand themselves as sexual subjects located in unequal ('raced' and classed) social contexts.
- Full Text:
- Date Issued: 2015
Multiple roles of non-timber forest products in ecologies, economies and livelihoods
- Authors: Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433970 , vital:73015 , ISBN 9781315818290 , https://doi.org/10.4324/9781315818290
- Description: The global climate models agree fairly well with each other for the next 20 years or so, with a predicted additional increase of 0.3-0.7oC in global mean surface air temperature, giving a total warming of 1.0-1.5oC (somewhat higher over land) (IPCC, 2013). Globally, rainfall is expected to increase, but some regions (such as most of the Mediterranean) will get drier and confidence in detailed rainfall predictions in most parts of the world is low. In the longer term, predictions vary greatly even for temperatures, depending on the choice of climate model and the assumptions made about future greenhouse gas emissions and carbon-cycle feedbacks. Temperatures over land are expected to increase by 3-6oC by 2100, compared with 2000, but the range of plausible values is considerably wider.
- Full Text:
- Date Issued: 2015
- Authors: Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433970 , vital:73015 , ISBN 9781315818290 , https://doi.org/10.4324/9781315818290
- Description: The global climate models agree fairly well with each other for the next 20 years or so, with a predicted additional increase of 0.3-0.7oC in global mean surface air temperature, giving a total warming of 1.0-1.5oC (somewhat higher over land) (IPCC, 2013). Globally, rainfall is expected to increase, but some regions (such as most of the Mediterranean) will get drier and confidence in detailed rainfall predictions in most parts of the world is low. In the longer term, predictions vary greatly even for temperatures, depending on the choice of climate model and the assumptions made about future greenhouse gas emissions and carbon-cycle feedbacks. Temperatures over land are expected to increase by 3-6oC by 2100, compared with 2000, but the range of plausible values is considerably wider.
- Full Text:
- Date Issued: 2015
Nanosecond nonlinear optical limiting properties of new trinuclear lanthanide phthalocyanines in solution and as thin films
- Sekhosana, Kutloana E, Amuhaya, Edith, Nyokong, Tebello
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189752 , vital:44928 , xlink:href="https://doi.org/10.1016/j.poly.2014.08.047"
- Description: 2,4,6-Tris[3-thio-9,10,16,17,23,24-hexa(4-tertbutylphenoxy) phthalocyaninato ytterbium (III) chloride]-s-triazin (3) and its lutetium counterpart (4) were synthesized. The nonlinear optical behavior of 3 and 4 were characterized in solution and when embedded in polymer as thin films. Thin films of complexes 3 and 4 in poly(bisphenol A carbonate) showed improved nonlinear optical properties when compared to solution. Complex 3 showed a lower threshold for optical limiting intensity (Ilim) than complex 4, and for phthalocyanines in general. Ilim values were even lower in films compared to solutions.
- Full Text:
- Date Issued: 2015
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189752 , vital:44928 , xlink:href="https://doi.org/10.1016/j.poly.2014.08.047"
- Description: 2,4,6-Tris[3-thio-9,10,16,17,23,24-hexa(4-tertbutylphenoxy) phthalocyaninato ytterbium (III) chloride]-s-triazin (3) and its lutetium counterpart (4) were synthesized. The nonlinear optical behavior of 3 and 4 were characterized in solution and when embedded in polymer as thin films. Thin films of complexes 3 and 4 in poly(bisphenol A carbonate) showed improved nonlinear optical properties when compared to solution. Complex 3 showed a lower threshold for optical limiting intensity (Ilim) than complex 4, and for phthalocyanines in general. Ilim values were even lower in films compared to solutions.
- Full Text:
- Date Issued: 2015
New school meets old school: journalism education in Africa’s newest country
- Authors: du Toit, Peter
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158691 , vital:40221 , https://hdl.handle.net/10520/EJC175767
- Description: South Sudanese journalists have a critical contribution to make in promoting peace, development and democracy in Africa's newest state, but many lack the training and skills to fulfill this potential.
- Full Text:
- Date Issued: 2015
- Authors: du Toit, Peter
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158691 , vital:40221 , https://hdl.handle.net/10520/EJC175767
- Description: South Sudanese journalists have a critical contribution to make in promoting peace, development and democracy in Africa's newest state, but many lack the training and skills to fulfill this potential.
- Full Text:
- Date Issued: 2015
NGOization: Complicity, Contradictions and Prospects
- Authors: Helliker, Kirk D
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144699 , vital:38371 , DOI: 10.1177/0021909614535552
- Description: This book focuses on the process of ‘NGOization’, namely, ‘the institutionalization, professionalization, depoliticization and demobilization of movements’ for social change (p. 1) by non-governmental organizations (NGOs). This process arises in and through the interface and relations between movements and NGOs and it highlights the overall system-maintenance role of NGOs. Of course, NGOs may not deliberately seek to depoliticize and demobilize movements. Rather, NGOization may involve the unintended consequences of the logic and dispositions of NGOs as a particular organization form.
- Full Text:
- Date Issued: 2015
- Authors: Helliker, Kirk D
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144699 , vital:38371 , DOI: 10.1177/0021909614535552
- Description: This book focuses on the process of ‘NGOization’, namely, ‘the institutionalization, professionalization, depoliticization and demobilization of movements’ for social change (p. 1) by non-governmental organizations (NGOs). This process arises in and through the interface and relations between movements and NGOs and it highlights the overall system-maintenance role of NGOs. Of course, NGOs may not deliberately seek to depoliticize and demobilize movements. Rather, NGOization may involve the unintended consequences of the logic and dispositions of NGOs as a particular organization form.
- Full Text:
- Date Issued: 2015
Non-timber forest products in livelihoods
- Authors: Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433699 , vital:72995 , ISBN 9781317916130 , https://www.routledge.com/Ecological-Sustainability-for-Non-timber-Forest-Products-Dynamics-and-Case/Shackleton-Pandey-Ticktin/p/book/9781138618251
- Description: That people from around the world have incorporated numerous plant and animal products into their lives, economies, cultures, traditions and histories is well known, and is the subject of a multitude of academic and non-academic documents across many disciplines. Historically, the use of these products has underlain trade between cultures and continents and the domestication of many present day crops and breeds (Laws 2011), so much so, that most urban citizens in the developed world have forgotten the original wild origins of current day staples in foods (eg corn, potatoes, rice, tomatoes, oranges, melons, sugar, coffee, tea, spices), medicines (aspirin, codeine, quinine, strychnine), fibres (cotton, sisal, coir, hemp), resins (lacquer, gum Arabic, rubber, turpentine), dyes (cochineal, indigo, saffron), intoxicants (tobacco, mushrooms, cannabis, opium) and artefacts. While such staple foods, medicines and the like used by the ‘western’urban consumer have become domesticated and are now almost exclusively produced in farming systems or replaced by synthetic substitutes, thousands of other animal, plant and fungi species are still widely used by peoples around the world.
- Full Text:
- Date Issued: 2015
- Authors: Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433699 , vital:72995 , ISBN 9781317916130 , https://www.routledge.com/Ecological-Sustainability-for-Non-timber-Forest-Products-Dynamics-and-Case/Shackleton-Pandey-Ticktin/p/book/9781138618251
- Description: That people from around the world have incorporated numerous plant and animal products into their lives, economies, cultures, traditions and histories is well known, and is the subject of a multitude of academic and non-academic documents across many disciplines. Historically, the use of these products has underlain trade between cultures and continents and the domestication of many present day crops and breeds (Laws 2011), so much so, that most urban citizens in the developed world have forgotten the original wild origins of current day staples in foods (eg corn, potatoes, rice, tomatoes, oranges, melons, sugar, coffee, tea, spices), medicines (aspirin, codeine, quinine, strychnine), fibres (cotton, sisal, coir, hemp), resins (lacquer, gum Arabic, rubber, turpentine), dyes (cochineal, indigo, saffron), intoxicants (tobacco, mushrooms, cannabis, opium) and artefacts. While such staple foods, medicines and the like used by the ‘western’urban consumer have become domesticated and are now almost exclusively produced in farming systems or replaced by synthetic substitutes, thousands of other animal, plant and fungi species are still widely used by peoples around the world.
- Full Text:
- Date Issued: 2015
Observed correlations of unsolicited ip traffic across five distinct network telescopes
- Irwin, Barry V W, Nkhumeleni, T
- Authors: Irwin, Barry V W , Nkhumeleni, T
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428569 , vital:72521 , https://www.jstor.org/stable/26502727
- Description: Using network telescopes to monitor unused IP address space provides a favourable environment for researchers to study and detect malware, denial of service, and scanning activities on the Internet. This research focuses on comparative and correlation analysis of traffic activity across five IPv4 network telescopes, each with an aperture size of /24 over a 12-month period. Time series representations of the traffic activity observed on these sensors were constructed. Using the cross- and auto-correlation methods of time series analysis, sensor data was quantitatively analysed with the resulting correlation of network telescopes’ traffic activity found to be moderate to high, dependent on grouping.
- Full Text:
- Date Issued: 2015
- Authors: Irwin, Barry V W , Nkhumeleni, T
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428569 , vital:72521 , https://www.jstor.org/stable/26502727
- Description: Using network telescopes to monitor unused IP address space provides a favourable environment for researchers to study and detect malware, denial of service, and scanning activities on the Internet. This research focuses on comparative and correlation analysis of traffic activity across five IPv4 network telescopes, each with an aperture size of /24 over a 12-month period. Time series representations of the traffic activity observed on these sensors were constructed. Using the cross- and auto-correlation methods of time series analysis, sensor data was quantitatively analysed with the resulting correlation of network telescopes’ traffic activity found to be moderate to high, dependent on grouping.
- Full Text:
- Date Issued: 2015
Observed correlations of unsolicited network traffic over five distinct IPv4 netblocks
- Nkhumeleni, Thiswilondi M, Irwin, Barry V W
- Authors: Nkhumeleni, Thiswilondi M , Irwin, Barry V W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430408 , vital:72689 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: Using network telescopes to monitor unused IP address space provides a favorable environment for researchers to study and detect malware, denial of service and scanning activities within global IPv4 address space. This research focuses on comparative and correlation analysis of traffic activity across the network of telescope sensors. Analysis is done using data collected over a 12 month period on five network telescopes each with an aperture size of/24, operated in disjoint IPv4 address space. These were considered as two distinct groupings. Time series’ representing time-based traffic activity observed on these sensors was constructed. Using the cross-and auto-correlation methods of time series analysis, moderate correlation of traffic activity was achieved between telescope sensors in each category. Weak to moderate correlation was calculated when comparing category A and category B network telescopes’ datasets. Results were significantly improved by considering TCP traffic separately. Moderate to strong correlation coefficients in each category were calculated when using TCP traffic only. UDP traffic analysis showed weaker correlation between sensors, however the uniformity of ICMP traffic showed correlation of traffic activity across all sensors. The results confirmed the visual observation of traffic relativity in telescope sensors within the same category and quantitatively analyzed the correlation of network telescopes’ traffic activity.
- Full Text:
- Date Issued: 2015
- Authors: Nkhumeleni, Thiswilondi M , Irwin, Barry V W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430408 , vital:72689 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: Using network telescopes to monitor unused IP address space provides a favorable environment for researchers to study and detect malware, denial of service and scanning activities within global IPv4 address space. This research focuses on comparative and correlation analysis of traffic activity across the network of telescope sensors. Analysis is done using data collected over a 12 month period on five network telescopes each with an aperture size of/24, operated in disjoint IPv4 address space. These were considered as two distinct groupings. Time series’ representing time-based traffic activity observed on these sensors was constructed. Using the cross-and auto-correlation methods of time series analysis, moderate correlation of traffic activity was achieved between telescope sensors in each category. Weak to moderate correlation was calculated when comparing category A and category B network telescopes’ datasets. Results were significantly improved by considering TCP traffic separately. Moderate to strong correlation coefficients in each category were calculated when using TCP traffic only. UDP traffic analysis showed weaker correlation between sensors, however the uniformity of ICMP traffic showed correlation of traffic activity across all sensors. The results confirmed the visual observation of traffic relativity in telescope sensors within the same category and quantitatively analyzed the correlation of network telescopes’ traffic activity.
- 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
Optimisation of an electrochemical impedance spectroscopy aptasensor by exploiting quartz crystal microbalance with dissipation signals
- Formisanoa, Nello, Jolly, Pawan, Bhalla, Nikhil, Cromhout, Mary, Flanagan, Shane P, Fogel, Ronen, Limson, Janice L, Estrela, Pedro
- Authors: Formisanoa, Nello , Jolly, Pawan , Bhalla, Nikhil , Cromhout, Mary , Flanagan, Shane P , Fogel, Ronen , Limson, Janice L , Estrela, Pedro
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431699 , vital:72797 , xlink:href="https://doi.org/10.1016/j.snb.2015.05.049"
- Description: The response of an Electrochemical Impedance Spectroscopy (EIS) sensor using DNA aptamers is affected by many factors, such as DNA density, charge and conformational changes upon DNA-target binding, and buffer conditions. We report here for the first time on the optimisation of an EIS aptamer-based sensor by using Quartz Crystal Microbalance with Dissipation mode (QCM-D). As a case study, we employed a DNA aptamer against Prostate-Specific Antigen (PSA). PSA detection was achieved by functionalising the gold sensor surface via thiol chemistry with different ratios of thiolated-DNA aptamer and 6-mercapto-1-hexanol (MCH) used as spacer molecules. PSA binding efficiency can be monitored by measuring QCM-D signals which not only provide information about the mass of PSA bound on the sensor surface, but also crucial information about the aptamer conformation and layer hydration.
- Full Text:
- Date Issued: 2015
- Authors: Formisanoa, Nello , Jolly, Pawan , Bhalla, Nikhil , Cromhout, Mary , Flanagan, Shane P , Fogel, Ronen , Limson, Janice L , Estrela, Pedro
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431699 , vital:72797 , xlink:href="https://doi.org/10.1016/j.snb.2015.05.049"
- Description: The response of an Electrochemical Impedance Spectroscopy (EIS) sensor using DNA aptamers is affected by many factors, such as DNA density, charge and conformational changes upon DNA-target binding, and buffer conditions. We report here for the first time on the optimisation of an EIS aptamer-based sensor by using Quartz Crystal Microbalance with Dissipation mode (QCM-D). As a case study, we employed a DNA aptamer against Prostate-Specific Antigen (PSA). PSA detection was achieved by functionalising the gold sensor surface via thiol chemistry with different ratios of thiolated-DNA aptamer and 6-mercapto-1-hexanol (MCH) used as spacer molecules. PSA binding efficiency can be monitored by measuring QCM-D signals which not only provide information about the mass of PSA bound on the sensor surface, but also crucial information about the aptamer conformation and layer hydration.
- Full Text:
- Date Issued: 2015
Optimisation of the emulsion liquid membrane composition and demulsification for rhodium extraction
- Moyo, Francis, Tandlich, Roman
- Authors: Moyo, Francis , Tandlich, Roman
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76743 , vital:30626 , https://doi.org/10.1515/lwr-2015-0002
- Description: This study was aimed at designing an optimised emulsion liquid membrane (ELM) for the extraction of rhodium from precious metal refinery wastewaters. The demulsification process and the structure of the optimised ELM are reported on. Two optimised ELMs were prepared. The first one contained a 30 % solution of toluene in kerosene as diluent with the following concentrations of the ELM components: 30.000 g/L (w/v) polyisobutylene, 10.870 g/L (m/v) of trioctyl amine and 51.001 g/L (m/v) of SPAN 80. The second ELM contained the same diluent, but the concentrations of the other ELM components in it were as follows: 20.000 g/l of polyisobutylene, 10.268 g/l trioctyl amine and 50.024 g/l of SPAN 80. The stripping phase was the same in both optimised ELMs, namely a 2 M solution of HNO3. The stripping phase and the diluent solution were mixed together in ratios of 1:1 and 2:1, respectively. Two methods were used to characterise the microdroplet diameters, i.e. optical microscopy and the Zeta-sizer. For the t-test, the p-value of 0.3018 at 5 % level of significance showed that there was statistically no significant difference in the mean micro-droplet size for 1:2 ELMs containing 20 g/l and 30 g/l of polyisobutylene after 40 minutes of emulsification. The best demulsification results were obtained using the chemical demulsification with polyethylene glycol with molecular weight of 400 g/mol (PEG 400) at 50 ± 1 °C for 24 hours. However, significant carryover of toluene, trioctyl amine and polyethylene glycol into the aqueous phase was observed.
- Full Text:
- Date Issued: 2015
- Authors: Moyo, Francis , Tandlich, Roman
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76743 , vital:30626 , https://doi.org/10.1515/lwr-2015-0002
- Description: This study was aimed at designing an optimised emulsion liquid membrane (ELM) for the extraction of rhodium from precious metal refinery wastewaters. The demulsification process and the structure of the optimised ELM are reported on. Two optimised ELMs were prepared. The first one contained a 30 % solution of toluene in kerosene as diluent with the following concentrations of the ELM components: 30.000 g/L (w/v) polyisobutylene, 10.870 g/L (m/v) of trioctyl amine and 51.001 g/L (m/v) of SPAN 80. The second ELM contained the same diluent, but the concentrations of the other ELM components in it were as follows: 20.000 g/l of polyisobutylene, 10.268 g/l trioctyl amine and 50.024 g/l of SPAN 80. The stripping phase was the same in both optimised ELMs, namely a 2 M solution of HNO3. The stripping phase and the diluent solution were mixed together in ratios of 1:1 and 2:1, respectively. Two methods were used to characterise the microdroplet diameters, i.e. optical microscopy and the Zeta-sizer. For the t-test, the p-value of 0.3018 at 5 % level of significance showed that there was statistically no significant difference in the mean micro-droplet size for 1:2 ELMs containing 20 g/l and 30 g/l of polyisobutylene after 40 minutes of emulsification. The best demulsification results were obtained using the chemical demulsification with polyethylene glycol with molecular weight of 400 g/mol (PEG 400) at 50 ± 1 °C for 24 hours. However, significant carryover of toluene, trioctyl amine and polyethylene glycol into the aqueous phase was observed.
- Full Text:
- Date Issued: 2015
Organosilicon compounds as fluorescent chemosensors for fluoride anion recognition
- Gai, Lizhi, Mack, John, Lu, Hua, Nyokong, Tebello, Li, Zhifang, Kobayashi, Nagao, Shen, Zhen
- Authors: Gai, Lizhi , Mack, John , Lu, Hua , Nyokong, Tebello , Li, Zhifang , Kobayashi, Nagao , Shen, Zhen
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241424 , vital:50938 , xlink:href="https://doi.org/10.1016/j.ccr.2014.10.009"
- Description: Recent developments in organosilicon-based chemosensors for F− recognition are reviewed. The design strategies for improving the photophysical properties of organosilicon-based chemosensors are elaborated, with an emphasis placed on their utility for biological applications. The photophysical properties and electronic structures are analyzed in depth with reference made to the results of molecular modeling calculation and possible future research directions are assessed.
- Full Text:
- Date Issued: 2015
- Authors: Gai, Lizhi , Mack, John , Lu, Hua , Nyokong, Tebello , Li, Zhifang , Kobayashi, Nagao , Shen, Zhen
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241424 , vital:50938 , xlink:href="https://doi.org/10.1016/j.ccr.2014.10.009"
- Description: Recent developments in organosilicon-based chemosensors for F− recognition are reviewed. The design strategies for improving the photophysical properties of organosilicon-based chemosensors are elaborated, with an emphasis placed on their utility for biological applications. The photophysical properties and electronic structures are analyzed in depth with reference made to the results of molecular modeling calculation and possible future research directions are assessed.
- Full Text:
- Date Issued: 2015
Overexpression, Purification and Characterisation of the Plasmodium falciparum Hsp70-z (PfHsp70-z) Protein
- Zininga, Tawanda, Achilonu, Ikechukwu, Hoppe, Heinrich, Prinsloo, Earl, Dirr, Heini, W, Shonhai, Addmore
- Authors: Zininga, Tawanda , Achilonu, Ikechukwu , Hoppe, Heinrich , Prinsloo, Earl , Dirr, Heini, W , Shonhai, Addmore
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431719 , vital:72799 , xlink:href="https://doi.org/10.1371/journal.pone.0129445"
- Description: Six Hsp70-like genes are represented on the genome of Plasmodium falciparum. Of these two occur in the cytosol: P. falciparum Hsp70-z (PfHsp70-z) and PfHsp70-1. PfHsp70-1 is a well characterised canonical Hsp70 that facilitates protein quality control and is crucial for the development of malaria parasites. There is very little known about PfHsp70-z. However, PfHsp70-z is known to be essential and is implicated in suppressing aggregation of asparagine-rich proteins of P. falciparum. In addition, its expression at the clinical stage of malaria correlates with disease prognosis. Based on structural evidence PfHsp70-z belongs to the Hsp110 family of proteins. Since Hsp110 proteins have been described as nucleotide exchange factors (NEFs) of their canonical Hsp70 counterparts, it has been speculated that PfHsp70-z may serve as a NEF of PfHsp70-1. In the current study, P. falciparum cells cultured in vitro were subjected to heat stress, triggering the enhanced expression of PfHsp70-z. Biochemical assays conducted using recombinant PfHsp70-z protein demonstrated that the protein is heat stable and possesses ATPase activity. Furthermore, we observed that PfHsp70-z is capable of self-association. The structural-functional features of PfHsp70-z provide further evidence for its role as a chaperone and possible nucleotide exchange factor of PfHsp70-1.
- Full Text:
- Date Issued: 2015
- Authors: Zininga, Tawanda , Achilonu, Ikechukwu , Hoppe, Heinrich , Prinsloo, Earl , Dirr, Heini, W , Shonhai, Addmore
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431719 , vital:72799 , xlink:href="https://doi.org/10.1371/journal.pone.0129445"
- Description: Six Hsp70-like genes are represented on the genome of Plasmodium falciparum. Of these two occur in the cytosol: P. falciparum Hsp70-z (PfHsp70-z) and PfHsp70-1. PfHsp70-1 is a well characterised canonical Hsp70 that facilitates protein quality control and is crucial for the development of malaria parasites. There is very little known about PfHsp70-z. However, PfHsp70-z is known to be essential and is implicated in suppressing aggregation of asparagine-rich proteins of P. falciparum. In addition, its expression at the clinical stage of malaria correlates with disease prognosis. Based on structural evidence PfHsp70-z belongs to the Hsp110 family of proteins. Since Hsp110 proteins have been described as nucleotide exchange factors (NEFs) of their canonical Hsp70 counterparts, it has been speculated that PfHsp70-z may serve as a NEF of PfHsp70-1. In the current study, P. falciparum cells cultured in vitro were subjected to heat stress, triggering the enhanced expression of PfHsp70-z. Biochemical assays conducted using recombinant PfHsp70-z protein demonstrated that the protein is heat stable and possesses ATPase activity. Furthermore, we observed that PfHsp70-z is capable of self-association. The structural-functional features of PfHsp70-z provide further evidence for its role as a chaperone and possible nucleotide exchange factor of PfHsp70-1.
- 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
Patriarchy, women, land and livelihoods on A1 farms in Zimbabwe
- Chiweshe, Manase K, Chakona, Loveness, Helliker, Kirk D
- Authors: Chiweshe, Manase K , Chakona, Loveness , Helliker, Kirk D
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71204 , vital:29812 , https://doi.org/10.1177/0021909614541083
- Description: In this article, we focus on patriarchy, women, land and livelihoods on A1 farms in Zimbabwe which arose from the fast track land reform programme. There is now significant literature on A1 farms in Zimbabwe. These studies include a number of ethnographic and comparative studies but this literature does not give sustained attention to patriarchy and women. In addition, though, a small number of works have appeared based upon a more focused gender analysis. We draw upon this more focused literature and offer fresh fieldwork evidence based on recent studies undertaken by two of the authors, in Goromonzi and Mazowe districts. At times, radical socio-spatial reorganisation such as fast track may destabilise systems of patriarchy. In the case of fast track, there has been a reconfiguration of relations between men and women yet this is uneven and contradictory and remains within the confines of patriarchal structures, practices and discourses. At the same time, women have manoeuvred and negotiated at local levels to enhance their lives and livelihoods.
- Full Text: false
- Date Issued: 2015
- Authors: Chiweshe, Manase K , Chakona, Loveness , Helliker, Kirk D
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71204 , vital:29812 , https://doi.org/10.1177/0021909614541083
- Description: In this article, we focus on patriarchy, women, land and livelihoods on A1 farms in Zimbabwe which arose from the fast track land reform programme. There is now significant literature on A1 farms in Zimbabwe. These studies include a number of ethnographic and comparative studies but this literature does not give sustained attention to patriarchy and women. In addition, though, a small number of works have appeared based upon a more focused gender analysis. We draw upon this more focused literature and offer fresh fieldwork evidence based on recent studies undertaken by two of the authors, in Goromonzi and Mazowe districts. At times, radical socio-spatial reorganisation such as fast track may destabilise systems of patriarchy. In the case of fast track, there has been a reconfiguration of relations between men and women yet this is uneven and contradictory and remains within the confines of patriarchal structures, practices and discourses. At the same time, women have manoeuvred and negotiated at local levels to enhance their lives and livelihoods.
- Full Text: false
- Date Issued: 2015
Pecha Kucha 1: Critical Studies in Sexualities and Reproduction
- Authors: Macleod, Catriona I
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143915 , vital:38294 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Despite enabling legislation and policies in the areas of sexualities and reproduction in South Africa, multiple challenges persist, including: forced sexual debut, sexual coercion and violence; HIV infection; hate crimes against lesbian women and gay men; unwanted and unsupportable pregnancies. While it is acknowledged that interventions (e.g., sexuality education programmes, the promotion of antenatal care use and the promotion of non-discrimination) have the potential to improve men’s and women’s sexual and reproductive lives. There are also multiple ways in which such programmes and the surrounding public discourses concerning sexuality and reproduction can serve in often unintended and unwitting ways to perpetuate oppressive heteronormative, gendered, racialised and class-based power relations. The Critical Studies in Sexualities and Reproduction research programme focuses on how particular discourses, narratives, and practices promote inclusion or exclusion, belonging or marginalisation, equity or inequity, justice or injustice, access to, or denial of, sexual and reproductive rights.
- Full Text:
- Date Issued: 2015
- Authors: Macleod, Catriona I
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143915 , vital:38294 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Despite enabling legislation and policies in the areas of sexualities and reproduction in South Africa, multiple challenges persist, including: forced sexual debut, sexual coercion and violence; HIV infection; hate crimes against lesbian women and gay men; unwanted and unsupportable pregnancies. While it is acknowledged that interventions (e.g., sexuality education programmes, the promotion of antenatal care use and the promotion of non-discrimination) have the potential to improve men’s and women’s sexual and reproductive lives. There are also multiple ways in which such programmes and the surrounding public discourses concerning sexuality and reproduction can serve in often unintended and unwitting ways to perpetuate oppressive heteronormative, gendered, racialised and class-based power relations. The Critical Studies in Sexualities and Reproduction research programme focuses on how particular discourses, narratives, and practices promote inclusion or exclusion, belonging or marginalisation, equity or inequity, justice or injustice, access to, or denial of, sexual and reproductive rights.
- Full Text:
- Date Issued: 2015
Pecha Kucha 2: Race and gender politics in cross-dressing, dressing-up, and drag
- Authors: Marx, Jacqueline
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143926 , vital:38295 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Sexuality is often less discernible than other markers of identity such as race and gender, which means that its perceptibility is often contingent on strategies that make it visible. Visibility is an especially important dimension in the shaping of lesbian and gay identities because people are generally assumed to be heterosexual. Making gay and lesbian identities visible is also an important political issue for people who have, historically, been threatened by the violence of public erasure. It is this aspect of gay and lesbian subjectivity – the politics of visibility – that is the topic of this presentation. We focus on gender and race politics in dressing-up, cross-dressing and drag performances - practices which make gay and lesbian sexualities visible, and consider the role that race and gender play in diminishing and exacerbating visibility.
- Full Text:
- Date Issued: 2015
- Authors: Marx, Jacqueline
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143926 , vital:38295 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Sexuality is often less discernible than other markers of identity such as race and gender, which means that its perceptibility is often contingent on strategies that make it visible. Visibility is an especially important dimension in the shaping of lesbian and gay identities because people are generally assumed to be heterosexual. Making gay and lesbian identities visible is also an important political issue for people who have, historically, been threatened by the violence of public erasure. It is this aspect of gay and lesbian subjectivity – the politics of visibility – that is the topic of this presentation. We focus on gender and race politics in dressing-up, cross-dressing and drag performances - practices which make gay and lesbian sexualities visible, and consider the role that race and gender play in diminishing and exacerbating visibility.
- Full Text:
- Date Issued: 2015
Pecha Kucha 3: Memories, photographs, and archives: On historicising ‘puberty’ in the present
- Authors: Pinto, Pedro
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143937 , vital:38296 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: In 1997, Valerie Walkerdine incited researchers to use memory and fantasy as devices to explore the gendered meanings of being a child and becoming adult. Since we all once were children, we are in the ambiguous – and therefore productive – position of being both informants and ethnographers of childhood experiences. Whilst drawing on a historical investigation on puberty science, this presentation is a hybrid experiment: it combines my memories of growing up in Portugal in the early 1980s and photographs of children taken in clinical interventions from the late nineteenth century to the first decades of the twentieth. In articulating these materials and their different temporalities, my purpose is to explore the techniques and the power relations in which pubertal development came to being thought of, and disciplined, in contemporary societies. In doing so, I invite the possibility of historicising experience as a strategy to critically analyse our medicalised present.
- Full Text:
- Date Issued: 2015
- Authors: Pinto, Pedro
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143937 , vital:38296 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: In 1997, Valerie Walkerdine incited researchers to use memory and fantasy as devices to explore the gendered meanings of being a child and becoming adult. Since we all once were children, we are in the ambiguous – and therefore productive – position of being both informants and ethnographers of childhood experiences. Whilst drawing on a historical investigation on puberty science, this presentation is a hybrid experiment: it combines my memories of growing up in Portugal in the early 1980s and photographs of children taken in clinical interventions from the late nineteenth century to the first decades of the twentieth. In articulating these materials and their different temporalities, my purpose is to explore the techniques and the power relations in which pubertal development came to being thought of, and disciplined, in contemporary societies. In doing so, I invite the possibility of historicising experience as a strategy to critically analyse our medicalised present.
- Full Text:
- Date Issued: 2015
Perceptions of the natural environment from a rural African perspective: a case of Cylondropuntia fulgida var. fulgida in Gwanda district, Zimbabwe
- Dube, Nqobizitha, Snowball, Jeanette D, Fraser, Gavin C G
- Authors: Dube, Nqobizitha , Snowball, Jeanette D , Fraser, Gavin C G
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68578 , vital:29289 , http://2015.essa.org.za/fullpaper/essa_2994.pdf
- Description: Publisher version , Community environmental perceptions are instrumental in environmental management programmes given that perspectives govern human-environment relations. Despite numerous studies on environmental perceptions, little is known about how the rural poor particularly in Africa conceptualize, live with, and respond to pressing environmental issues facing them. As such, this paper uses the case of an invasive alien plant (IAP) (Cylindropuntia fulgida var. fulgida (Cff)) in a rural community (Gwanda district, Zimbabwe) to unveil the conceptualisation of the natural environment from a rural African perspective. This paper discloses the environmental worldview of the community and explains the formulation of the attitudes by the local households towards species in the environment. The study uses two horizontal dimensions of environmental attitudes formulation (New Environmental Paradigm (NEP) Scale and Kellet’s (1996) classification of environmental values). Data was collected using a questionnaire survey, group discussions and key informant interviews. A sample of 156 individuals comprised the study respondents. Results showed the residents of rural Gwanda district to hold both a conservation and utilisation conviction (syncretic view) towards the environment. However, utilisation outweighs conservation. Furthermore, older residents are more inclined to conservation in comparison to the youth. The study also divulged that the origin of a species in the natural environment was insignificant to the host community. However, the livelihood effects that species had (regardless of origins) were the major determinants of attitudes developed towards it.
- Full Text:
- Date Issued: 2015
- Authors: Dube, Nqobizitha , Snowball, Jeanette D , Fraser, Gavin C G
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68578 , vital:29289 , http://2015.essa.org.za/fullpaper/essa_2994.pdf
- Description: Publisher version , Community environmental perceptions are instrumental in environmental management programmes given that perspectives govern human-environment relations. Despite numerous studies on environmental perceptions, little is known about how the rural poor particularly in Africa conceptualize, live with, and respond to pressing environmental issues facing them. As such, this paper uses the case of an invasive alien plant (IAP) (Cylindropuntia fulgida var. fulgida (Cff)) in a rural community (Gwanda district, Zimbabwe) to unveil the conceptualisation of the natural environment from a rural African perspective. This paper discloses the environmental worldview of the community and explains the formulation of the attitudes by the local households towards species in the environment. The study uses two horizontal dimensions of environmental attitudes formulation (New Environmental Paradigm (NEP) Scale and Kellet’s (1996) classification of environmental values). Data was collected using a questionnaire survey, group discussions and key informant interviews. A sample of 156 individuals comprised the study respondents. Results showed the residents of rural Gwanda district to hold both a conservation and utilisation conviction (syncretic view) towards the environment. However, utilisation outweighs conservation. Furthermore, older residents are more inclined to conservation in comparison to the youth. The study also divulged that the origin of a species in the natural environment was insignificant to the host community. However, the livelihood effects that species had (regardless of origins) were the major determinants of attitudes developed towards it.
- Full Text:
- Date Issued: 2015