HIV/AIDS and other household shocks as catalysts of local commercialization of non-timber forest products in Southern Africa
- Weyer, Dylan J, Shackleton, Charlie M, Adam, Y O
- Authors: Weyer, Dylan J , Shackleton, Charlie M , Adam, Y O
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398223 , vital:69385 , xlink:href="https://doi.org/10.1111/dpr.12261"
- Description: Local trade in non-timber forest products (NTFPs) is increasing globally, yet the causes have been little studied. We examine household shock as a driver of NTFP trade in five southern African countries, with an emphasis on HIV/AIDS-related illness and death. Over the past two years, 95% of trader households experienced at least one shock, with family illness and death recorded for 68% and 42% of households, respectively. Almost 40% had entered the trade because of HIV/AIDS-related shocks. Additional shocks included natural disasters, crop pests or failure and livestock loss. The sale of NTFPs was the third most common coping strategy, after kinship and agricultural adjustments. Coping strategies differed between sites and type of shock.
- Full Text:
- Date Issued: 2018
- Authors: Weyer, Dylan J , Shackleton, Charlie M , Adam, Y O
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398223 , vital:69385 , xlink:href="https://doi.org/10.1111/dpr.12261"
- Description: Local trade in non-timber forest products (NTFPs) is increasing globally, yet the causes have been little studied. We examine household shock as a driver of NTFP trade in five southern African countries, with an emphasis on HIV/AIDS-related illness and death. Over the past two years, 95% of trader households experienced at least one shock, with family illness and death recorded for 68% and 42% of households, respectively. Almost 40% had entered the trade because of HIV/AIDS-related shocks. Additional shocks included natural disasters, crop pests or failure and livestock loss. The sale of NTFPs was the third most common coping strategy, after kinship and agricultural adjustments. Coping strategies differed between sites and type of shock.
- Full Text:
- Date Issued: 2018
Household food insecurity along an agro-ecological gradient influences children’s nutritional status in South Africa
- Chakona, Gamuchirai, Shackleton, Charlie M
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179836 , vital:43193 , xlink:href="https://doi.org/10.3389/fnut.2017.00072"
- Description: The burden of food insecurity and malnutrition is a severe problem experienced by many poor households and children under the age of five are at high risk. The objective of the study was to examine household food insecurity, dietary diversity, and child nutritional status in relation to local context which influences access to and ability to grow food in South Africa and explore the links and associations between these and household socio-economic status. Using a 48-h dietary recall method, we interviewed 554 women from randomly selected households along a rural–urban continuum in three towns situated along an agro-ecological gradient. The Household Dietary Diversity Scores (HDDS) and the Household Food Insecurity Access Scale (HFIAS) tools were used to measure household dietary diversity and food insecurity, respectively. Anthropometric measurements with 216 children (2–5 years) from the sampled households were conducted using height-for-age and mid-upper arm circumference (MUAC) as indicators of stunting and wasting, respectively. The key findings were that mean HDDS declined with decreasing agro-ecological potential from the wettest site (8.44 ± 1.72) to the other two drier sites (7.83 ± 1.59 and 7.76 ± 1.63). The mean HFIAS followed the opposite trend. Stunted growth was the dominant form of malnutrition detected in 35% of children and 18% of children were wasted. Child wasting was greatest at the site with lowest agro-ecological potential. Children from households with low HDDS had large MUAC which showed an inverse association among HDDS and obesity. Areas with agro-ecological potential had lower prevalence of food insecurity and wasting in children. Agro-ecological potential has significant influence on children’s nutritional status, which is also related to household food security and socio-economic status. Dependence on food purchasing and any limitations in households’ income, access to land and food, can result in different forms of malnutrition in children. Responses to address malnutrition in South Africa need to be prioritized and move beyond relying on food security and nutritional-specific interventions, but rather on nutrition-specific and sensitive programs and approaches; and building an enabling environment. Land availability, agriculture (including climate-smart agriculture especially in drier areas), and wild foods usage should be promoted.
- Full Text:
- Date Issued: 2018
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179836 , vital:43193 , xlink:href="https://doi.org/10.3389/fnut.2017.00072"
- Description: The burden of food insecurity and malnutrition is a severe problem experienced by many poor households and children under the age of five are at high risk. The objective of the study was to examine household food insecurity, dietary diversity, and child nutritional status in relation to local context which influences access to and ability to grow food in South Africa and explore the links and associations between these and household socio-economic status. Using a 48-h dietary recall method, we interviewed 554 women from randomly selected households along a rural–urban continuum in three towns situated along an agro-ecological gradient. The Household Dietary Diversity Scores (HDDS) and the Household Food Insecurity Access Scale (HFIAS) tools were used to measure household dietary diversity and food insecurity, respectively. Anthropometric measurements with 216 children (2–5 years) from the sampled households were conducted using height-for-age and mid-upper arm circumference (MUAC) as indicators of stunting and wasting, respectively. The key findings were that mean HDDS declined with decreasing agro-ecological potential from the wettest site (8.44 ± 1.72) to the other two drier sites (7.83 ± 1.59 and 7.76 ± 1.63). The mean HFIAS followed the opposite trend. Stunted growth was the dominant form of malnutrition detected in 35% of children and 18% of children were wasted. Child wasting was greatest at the site with lowest agro-ecological potential. Children from households with low HDDS had large MUAC which showed an inverse association among HDDS and obesity. Areas with agro-ecological potential had lower prevalence of food insecurity and wasting in children. Agro-ecological potential has significant influence on children’s nutritional status, which is also related to household food security and socio-economic status. Dependence on food purchasing and any limitations in households’ income, access to land and food, can result in different forms of malnutrition in children. Responses to address malnutrition in South Africa need to be prioritized and move beyond relying on food security and nutritional-specific interventions, but rather on nutrition-specific and sensitive programs and approaches; and building an enabling environment. Land availability, agriculture (including climate-smart agriculture especially in drier areas), and wild foods usage should be promoted.
- Full Text:
- Date Issued: 2018
How important is green infrastructure in small and medium-sized towns? Lessons from South Africa
- Shackleton, Charlie M, Blair, Andrew, De Lacy, Peter, Kaoma, Humphrey, Mugwagwa, Noster, Dalu, Mwazvita, Walton, Wesley
- Authors: Shackleton, Charlie M , Blair, Andrew , De Lacy, Peter , Kaoma, Humphrey , Mugwagwa, Noster , Dalu, Mwazvita , Walton, Wesley
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398321 , vital:69400 , xlink:href="https://doi.org/10.1016/j.landurbplan.2016.12.007"
- Description: The current nature and challenges of urbanisation in sub-Saharan Africa display several unique features only weakly evident on other continents. Key ones include the current high rates of population growth, inadequate planning and governance systems, concentration in small and medium-sized towns, and increasing urban poverty. These shape the extent, nature and use of ecosystem services provided by urban green infrastructure. This paper first examines the location of green infrastructure across nine towns, showing that it is unequal between suburbs and that the bulk is located under private tenure (74%) rather than in public spaces. We then consider the extent and patterns of use of selected provisioning and cultural ecosystem services from green infrastructure in different locations within towns, including private gardens, public parks and street trees. The results show significant use of green infrastructure for a range of provisioning and cultural services as well as its contribution to spiritual and mental wellbeing. Provisioning contributions are both in regular support of livelihood needs as well as increased use after a covariate shock (a flood), both of which help reduce household vulnerability. Lastly, our results show the expressed level of support and willingness-to-pay or work amongst urban residents for green infrastructure and the services it provides. Whilst the composite results indicate marked variation between and within towns, they show that there is widespread use of green infrastructure for both basic needs as well as for more aesthetic and psycho-spiritual appreciation and recreation, in small and medium-sized towns in a developing country such as South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Shackleton, Charlie M , Blair, Andrew , De Lacy, Peter , Kaoma, Humphrey , Mugwagwa, Noster , Dalu, Mwazvita , Walton, Wesley
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398321 , vital:69400 , xlink:href="https://doi.org/10.1016/j.landurbplan.2016.12.007"
- Description: The current nature and challenges of urbanisation in sub-Saharan Africa display several unique features only weakly evident on other continents. Key ones include the current high rates of population growth, inadequate planning and governance systems, concentration in small and medium-sized towns, and increasing urban poverty. These shape the extent, nature and use of ecosystem services provided by urban green infrastructure. This paper first examines the location of green infrastructure across nine towns, showing that it is unequal between suburbs and that the bulk is located under private tenure (74%) rather than in public spaces. We then consider the extent and patterns of use of selected provisioning and cultural ecosystem services from green infrastructure in different locations within towns, including private gardens, public parks and street trees. The results show significant use of green infrastructure for a range of provisioning and cultural services as well as its contribution to spiritual and mental wellbeing. Provisioning contributions are both in regular support of livelihood needs as well as increased use after a covariate shock (a flood), both of which help reduce household vulnerability. Lastly, our results show the expressed level of support and willingness-to-pay or work amongst urban residents for green infrastructure and the services it provides. Whilst the composite results indicate marked variation between and within towns, they show that there is widespread use of green infrastructure for both basic needs as well as for more aesthetic and psycho-spiritual appreciation and recreation, in small and medium-sized towns in a developing country such as South Africa.
- Full Text:
- Date Issued: 2018
Import licensing regulation within the WTO: a case study of the dispute between Zimbabwe and South Africa over the Control of Goods (Open General Import Licence) Notice of 2016 (Statutory Instrument 64)
- Kamunjoma, Charles https://orcid.org/0000-0002-1930-4341
- Authors: Kamunjoma, Charles https://orcid.org/0000-0002-1930-4341
- Date: 2018
- Subjects: Import quotas , Customs unions , Africa, Southern -- Economic integration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27854 , vital:70097
- Description: Over the years, Zimbabwe has arbitrarily enforced trade restrictive measures including mandatory inspections on certain products, duty increases, surtaxes and import permits on basic products such as cooking oil. The measures have been allegedly targeting goods from South Africa. Amongst the most recent restrictive measures imposed by Zimbabwe is SI 64 of 2016 that now operates as SI 122 of 2017. In response to SI 64, for the first time, South Africa threatened retaliation. As a result, there is visible trade tension between Zimbabwe and South Africa. With the absence of an effective dispute settlement mechanism within SADC, or most African Regional Economic Communities RECs for that matter, a WTO approach to the issue will provide valuable insights on how else South Africa (and other African countries) can deal with cross-border trade problems such as the ones posed by SI 64. , Thesis (LLM) -- Faculty of Law, 2018
- Full Text:
- Date Issued: 2018
- Authors: Kamunjoma, Charles https://orcid.org/0000-0002-1930-4341
- Date: 2018
- Subjects: Import quotas , Customs unions , Africa, Southern -- Economic integration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27854 , vital:70097
- Description: Over the years, Zimbabwe has arbitrarily enforced trade restrictive measures including mandatory inspections on certain products, duty increases, surtaxes and import permits on basic products such as cooking oil. The measures have been allegedly targeting goods from South Africa. Amongst the most recent restrictive measures imposed by Zimbabwe is SI 64 of 2016 that now operates as SI 122 of 2017. In response to SI 64, for the first time, South Africa threatened retaliation. As a result, there is visible trade tension between Zimbabwe and South Africa. With the absence of an effective dispute settlement mechanism within SADC, or most African Regional Economic Communities RECs for that matter, a WTO approach to the issue will provide valuable insights on how else South Africa (and other African countries) can deal with cross-border trade problems such as the ones posed by SI 64. , Thesis (LLM) -- Faculty of Law, 2018
- Full Text:
- Date Issued: 2018
Improved Photophysical and Photochemical Properties of Thiopheneethoxy Substituted Metallophthalocyanines on Immobilization onto Gold‐speckled Silica Nanoparticles
- Dube, Edith, Oluwole, David O, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
In-situ synthesis of gold nanoparticles on graphene quantum dots-phthalocyanine nanoplatforms: First description of the photophysical and surface enhanced Raman scattering behaviour
- Nwahara, Nnamdi, Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187638 , vital:44682 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187638 , vital:44682 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
In-situ synthesis of gold nanoparticles on graphene quantum dots-phthalocyanine nanoplatforms: First description of the photophysical and surface enhanced Raman scattering behaviour
- Nwahara, Nnamdi, Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188183 , vital:44730 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188183 , vital:44730 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
Incorporation of metal free and Ga 5, 10, 15, 20-tetrakis (4-bromophenyl) porphyrin into Pluronic F127-folic acid micelles
- Managa, Muthumuni, Ngoy, Bucolome P, Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Managa, Muthumuni , Ngoy, Bucolome P , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233256 , vital:50073 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.09.045"
- Description: ClGa 5,10,15,20-Tetrakis (4-bromophenyl) porphyrinato (ClGaTBrPP) and its metal free derivative were successfully synthesized and incorporated into Pluronic F127 polymeric micelles that has been conjugated to folic acid (FA) to form ClGaTBrPP-F127-FA (or H2TBrPP-F127-FA). For comparison, ClGaTBrPP-F127 and H2TBrPP-F127 (without FA) were also formed. The singlet oxygen quantum yield for ClGaTBrPP-F127-FA was higher (ΦΔ = 0.44) than that of H2TBrPP-F127-FA (ΦΔ = 0.37), due to the heavy atom effect of Ga in the former which encourages intersystem crossing to the triplet state. The same applies to ClGaTBrPP-F127 (ΦΔ = 0.47) and H2TBrPP-F127 (ΦΔ = 0.41). Thus, ΦΔ values decreased in the presence of FA, but still high enough for practical application of the nanodrug system. The binding constants Kb were determined to be 1.08 × 104 M−1, 2.51 × 105 M−1, 1.52 × 103 and 2.68 × 103 for H2TBrPP+F127-FA, ClGaTBrPP+F127-FA, ClGaTBrPP-F127 and H2TBrPP-F127, respectively. The Kp values were determined in biphasic octanol and water system.
- Full Text:
- Date Issued: 2018
- Authors: Managa, Muthumuni , Ngoy, Bucolome P , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233256 , vital:50073 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.09.045"
- Description: ClGa 5,10,15,20-Tetrakis (4-bromophenyl) porphyrinato (ClGaTBrPP) and its metal free derivative were successfully synthesized and incorporated into Pluronic F127 polymeric micelles that has been conjugated to folic acid (FA) to form ClGaTBrPP-F127-FA (or H2TBrPP-F127-FA). For comparison, ClGaTBrPP-F127 and H2TBrPP-F127 (without FA) were also formed. The singlet oxygen quantum yield for ClGaTBrPP-F127-FA was higher (ΦΔ = 0.44) than that of H2TBrPP-F127-FA (ΦΔ = 0.37), due to the heavy atom effect of Ga in the former which encourages intersystem crossing to the triplet state. The same applies to ClGaTBrPP-F127 (ΦΔ = 0.47) and H2TBrPP-F127 (ΦΔ = 0.41). Thus, ΦΔ values decreased in the presence of FA, but still high enough for practical application of the nanodrug system. The binding constants Kb were determined to be 1.08 × 104 M−1, 2.51 × 105 M−1, 1.52 × 103 and 2.68 × 103 for H2TBrPP+F127-FA, ClGaTBrPP+F127-FA, ClGaTBrPP-F127 and H2TBrPP-F127, respectively. The Kp values were determined in biphasic octanol and water system.
- Full Text:
- Date Issued: 2018
Influence of land cover, proximity to streams and household topographical location on flooding impact in informal settlements in the Eastern Cape, South Africa
- Dalu, Mwazvita, Shackleton, Charlie M, Dalu, Tatenda
- Authors: Dalu, Mwazvita , Shackleton, Charlie M , Dalu, Tatenda
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182089 , vital:43799 , xlink:href="https://doi.org/10.1016/j.ijdrr.2017.12.009"
- Description: Patterns of land use, household topographical location and state of natural vegetation influence the spatial distribution of flooding impact. Using field observations and GIS mapping techniques, we investigated how landscape factors influenced structural flooding impact in informal settlements. This study was carried out in the informal settlements of the Eastern Cape Province of South Africa, after the October 2012 floods. Increasing slope significantly raised the probability and level of damage by at least 30% in five of the seven sites, whereas proximity to river and wetlands (more than 100 m) was significant in only two of the sites and at lower levels. Multi-regression analysis highlighted that land cover, proximity to streams and household topographical location influenced the impact of flooding on housing structures. We found that the impact on housing structures in informal settlements during the floods were significantly influenced by their proximity to water bodies, slope factor and patterns of land cover.
- Full Text:
- Date Issued: 2018
- Authors: Dalu, Mwazvita , Shackleton, Charlie M , Dalu, Tatenda
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182089 , vital:43799 , xlink:href="https://doi.org/10.1016/j.ijdrr.2017.12.009"
- Description: Patterns of land use, household topographical location and state of natural vegetation influence the spatial distribution of flooding impact. Using field observations and GIS mapping techniques, we investigated how landscape factors influenced structural flooding impact in informal settlements. This study was carried out in the informal settlements of the Eastern Cape Province of South Africa, after the October 2012 floods. Increasing slope significantly raised the probability and level of damage by at least 30% in five of the seven sites, whereas proximity to river and wetlands (more than 100 m) was significant in only two of the sites and at lower levels. Multi-regression analysis highlighted that land cover, proximity to streams and household topographical location influenced the impact of flooding on housing structures. We found that the impact on housing structures in informal settlements during the floods were significantly influenced by their proximity to water bodies, slope factor and patterns of land cover.
- Full Text:
- Date Issued: 2018
Informal urban fuelwood markets in South Africa in the context of socio-economic change
- Guild, J, Shackleton, Charlie M
- Authors: Guild, J , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179779 , vital:43179 , xlink:href="https://doi.org/10.1016/j.enpol.2018.03.023"
- Description: In developing countries, fuelwood is important to livelihoods and energy security because it is used for heating, cooking and can provide additional income to households through trade. The global trade in fuelwood is valued between USD 4–26 billion per annum. In South Africa, fuelwood is a widely used domestic energy source; but how that has changed with rapid urbanisation and socio-economic development over the last two decades is unknown. This study examined the presence and nature of urban fuelwood markets in 39 urban areas of the Eastern Cape and Limpopo provinces. Data were collected from 170 informal fuelwood sellers regarding the prevalence, structure, characteristics, and changes over time of the informal fuelwood markets. Over 80% of the sampled towns had an informal fuelwood market and there was a positive relationship between the number of sellers and town population size. For most sellers, the fuelwood trade was their primary occupation and the income earned was supplemented by government social grants. Sellers earned, on average, over US$9 per day. These results show that despite rapid urbanisation and socio-economic development, fuelwood remains an important domestic fuel in towns and cities of South Africa, and an income source for the urban poor.
- Full Text:
- Date Issued: 2018
- Authors: Guild, J , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179779 , vital:43179 , xlink:href="https://doi.org/10.1016/j.enpol.2018.03.023"
- Description: In developing countries, fuelwood is important to livelihoods and energy security because it is used for heating, cooking and can provide additional income to households through trade. The global trade in fuelwood is valued between USD 4–26 billion per annum. In South Africa, fuelwood is a widely used domestic energy source; but how that has changed with rapid urbanisation and socio-economic development over the last two decades is unknown. This study examined the presence and nature of urban fuelwood markets in 39 urban areas of the Eastern Cape and Limpopo provinces. Data were collected from 170 informal fuelwood sellers regarding the prevalence, structure, characteristics, and changes over time of the informal fuelwood markets. Over 80% of the sampled towns had an informal fuelwood market and there was a positive relationship between the number of sellers and town population size. For most sellers, the fuelwood trade was their primary occupation and the income earned was supplemented by government social grants. Sellers earned, on average, over US$9 per day. These results show that despite rapid urbanisation and socio-economic development, fuelwood remains an important domestic fuel in towns and cities of South Africa, and an income source for the urban poor.
- Full Text:
- Date Issued: 2018
Integrating chemical control with sterile insect releases in an integrated pest management programme for Thaumatotibia leucotreta
- Nepgen, Eugene, Moore, Sean D, Hill, Martin P
- Authors: Nepgen, Eugene , Moore, Sean D , Hill, Martin P
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423770 , vital:72092 , xlink:href="https://doi.org/10.1111/jen.12487"
- Description: False codling moth Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is an important indigenous pest of citrus in southern Africa. Successful control is dependent upon integration of area-wide sterile insect releases and other suppression methods. The aim of this work was to test pyrethroid and organophosphate-based insecticides (tau-fluvalinate and chlorpyrifos) for their residual effect on mortality of released irradiated T. leucotreta male moths. Both of these insecticides were effective in killing irradiated T. leucotreta for 7 days after application on leaves, after which degradation of the active ingredient resulted in a marked reduction in efficacy after 14 days and rendering them harmless. Mortality was found to be similar for irradiated and non-irradiated male T. leucotreta after treatment. Consequently, even though these insecticides might have an effect on moths in the field, ratios of sterile:wild moths should not be altered. Supporting field data from six sites in the Sundays River Valley over a season of sterile insect releases showed the conventional chemical crop protection programme to be as effective as an integrated pest management programme in facilitating effective control of T. leucotreta through sterile insect releases. The study also confirmed that the ratios of sterile:wild male moths in the commercial citrus orchards were not affected by the application of insecticides. These findings confirm the high potential of sterile insect releases for control of T. leucotreta in citrus.
- Full Text:
- Date Issued: 2018
- Authors: Nepgen, Eugene , Moore, Sean D , Hill, Martin P
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423770 , vital:72092 , xlink:href="https://doi.org/10.1111/jen.12487"
- Description: False codling moth Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is an important indigenous pest of citrus in southern Africa. Successful control is dependent upon integration of area-wide sterile insect releases and other suppression methods. The aim of this work was to test pyrethroid and organophosphate-based insecticides (tau-fluvalinate and chlorpyrifos) for their residual effect on mortality of released irradiated T. leucotreta male moths. Both of these insecticides were effective in killing irradiated T. leucotreta for 7 days after application on leaves, after which degradation of the active ingredient resulted in a marked reduction in efficacy after 14 days and rendering them harmless. Mortality was found to be similar for irradiated and non-irradiated male T. leucotreta after treatment. Consequently, even though these insecticides might have an effect on moths in the field, ratios of sterile:wild moths should not be altered. Supporting field data from six sites in the Sundays River Valley over a season of sterile insect releases showed the conventional chemical crop protection programme to be as effective as an integrated pest management programme in facilitating effective control of T. leucotreta through sterile insect releases. The study also confirmed that the ratios of sterile:wild male moths in the commercial citrus orchards were not affected by the application of insecticides. These findings confirm the high potential of sterile insect releases for control of T. leucotreta in citrus.
- Full Text:
- Date Issued: 2018
Interaction of catechol O-methyltransferase with gold and silver nanoparticles
- Authors: Usman, Aminu
- Date: 2018
- Subjects: Parkinson's disease , Methyltransferases , Catechol , Nanoparticles
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/61818 , vital:28063 , DOI https://doi.org/10.21504/10962/61818
- Description: Catechol O-methyltransferase (S-adenosyl-Z-methionine: catechol O-methyltransferase; COMT; EC 2.1.1.6) is a ubiquitous enzyme that catalyses the transfer of a methyl group from the cofactor, S-adenosyl-Z-methionine (SAM) to a hydroxyl group of endogenous and exogenous catechol-containing moieties. The physiological role of this enzyme is the methylation and thereby inactivation of the catechol-containing bio-active and bio-toxic compounds, including catechol-neurotransmitters, catechol-estrogens and catechol-containing drugs. Activity of this enzyme is implicated in the treatment of Parkinson’s disease and is associated with other diseases including breast cancer and an array neuropsychological disorders, such as schizophrenia. This thesis explores the use of gold and silver nanoparticles (NPs) (AuNPs and AgNPs) to inhibit the catalytic activity of mammalian COMT. Because of its accessibility and availability, we initially investigated bovine soluble COMT (BSCOMT) from liver tissue. Bioinformatic analyses and structural modeling revealed high (>90%) sequence similarity between BSCOMT and human soluble COMT (HSCOMT). BSCOMT was partially purified to 7.78 fold, 1.65% yield and had a specific activity of 0.052 U/mg. It had pH and temperature optima of 8.5 and 40oC, respectively. The Km, Vmax, Kcat and Kcat/Km towards esculetin methylation were respectively 1.475±0.130 pM, 0.0353±0.001 pmol/ml/min, 1.748 x 10-2±5.0x10-4 min-1 and 1.18x10-2 M-1. min-1. HSCOMT was expressed in Escherichia coli BL21(DE3) which showed optimal activity for esculetin methylation at pH and temperature of 7.0 and 30°C, respectively. It was purified to 5.62 fold, 22.6% yield with a specific activity of 3.85 U/mg. HSCOMT kinetic plots, upon incubation of the reaction mixture at 30°C for 5 min before addition of SAM was hyperbolic with Km, Vmax, Kcat and Kcat/Km values of 1.79 pM, 0.412 pmol/ml/min, 2.08 min-1 and 1.165 M-1. min-1, respectively. AuNPs and AgNPs showed a concentration dependent inhibition of HSCOMT activity upon increasing the 5 min incubation time to 1 h. Interestingly, HSCOMT kinetics, with 1 h incubation at 30°C, showed a sigmoidal curve, as well as increased activity. Incubation of the reaction mixture in the presence of 60 pM AuNPs and/or AgNPs for 1 hreversed the observed sigmoidal to a hyperbolic curve, with kinetic parameters comparable to those of 5 min incubation. SDS-PAGE analyses of HSCOMT after the kinetic experiments showed the enzyme incubated for 5 min as a monomer, while that which was incubated for 1 h migrated substantially as dimer. However, the HSCOMT incubated for 1 h in the presence of 60 pM AuNPs and/or AgNPs migrated as a monomer. This indicated that the extension of the incubation period allowed the dimerization of HSCOMT, which exhibited sigmoidal kinetics and higher activity. The presence of NPs impeded the HSCOMT dimerization which decreased the activity. Varying the concentration of SAM suggested that SAM had an allosteric modulatory effect on HSCOMT. Absorption spectroscopy indicated adsorption of HSCOMT on the gold and silver NP surfaces and the formation of NPs-HSCOMT corona. Fluorescence spectroscopy showed that the interaction of HSCOMT with both gold and silver NPs was governed by a static quenching mechanism, implying the formation of a non-fluorescent fluorophore-NP complex at the ground state. Further fluorometric analyses indicated that both gold and silver NPs had contact with Trp143; that the interactions were spontaneous and were driven by electrostatic interactions. Fourier transform infrared spectroscopic studies showed the adsorption of HSCOMT of the NPs surfaces to cause relaxation of the enzyme’s B-sheet structures. Molecular docking studies indicated involvement of largely hydrophilic amino acids, with the interacting distances of less than 3.5A. These findings signify the potential of nanotechnology in the control of COMT catalytic activity for the management of the COMT-related disorders. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
- Authors: Usman, Aminu
- Date: 2018
- Subjects: Parkinson's disease , Methyltransferases , Catechol , Nanoparticles
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/61818 , vital:28063 , DOI https://doi.org/10.21504/10962/61818
- Description: Catechol O-methyltransferase (S-adenosyl-Z-methionine: catechol O-methyltransferase; COMT; EC 2.1.1.6) is a ubiquitous enzyme that catalyses the transfer of a methyl group from the cofactor, S-adenosyl-Z-methionine (SAM) to a hydroxyl group of endogenous and exogenous catechol-containing moieties. The physiological role of this enzyme is the methylation and thereby inactivation of the catechol-containing bio-active and bio-toxic compounds, including catechol-neurotransmitters, catechol-estrogens and catechol-containing drugs. Activity of this enzyme is implicated in the treatment of Parkinson’s disease and is associated with other diseases including breast cancer and an array neuropsychological disorders, such as schizophrenia. This thesis explores the use of gold and silver nanoparticles (NPs) (AuNPs and AgNPs) to inhibit the catalytic activity of mammalian COMT. Because of its accessibility and availability, we initially investigated bovine soluble COMT (BSCOMT) from liver tissue. Bioinformatic analyses and structural modeling revealed high (>90%) sequence similarity between BSCOMT and human soluble COMT (HSCOMT). BSCOMT was partially purified to 7.78 fold, 1.65% yield and had a specific activity of 0.052 U/mg. It had pH and temperature optima of 8.5 and 40oC, respectively. The Km, Vmax, Kcat and Kcat/Km towards esculetin methylation were respectively 1.475±0.130 pM, 0.0353±0.001 pmol/ml/min, 1.748 x 10-2±5.0x10-4 min-1 and 1.18x10-2 M-1. min-1. HSCOMT was expressed in Escherichia coli BL21(DE3) which showed optimal activity for esculetin methylation at pH and temperature of 7.0 and 30°C, respectively. It was purified to 5.62 fold, 22.6% yield with a specific activity of 3.85 U/mg. HSCOMT kinetic plots, upon incubation of the reaction mixture at 30°C for 5 min before addition of SAM was hyperbolic with Km, Vmax, Kcat and Kcat/Km values of 1.79 pM, 0.412 pmol/ml/min, 2.08 min-1 and 1.165 M-1. min-1, respectively. AuNPs and AgNPs showed a concentration dependent inhibition of HSCOMT activity upon increasing the 5 min incubation time to 1 h. Interestingly, HSCOMT kinetics, with 1 h incubation at 30°C, showed a sigmoidal curve, as well as increased activity. Incubation of the reaction mixture in the presence of 60 pM AuNPs and/or AgNPs for 1 hreversed the observed sigmoidal to a hyperbolic curve, with kinetic parameters comparable to those of 5 min incubation. SDS-PAGE analyses of HSCOMT after the kinetic experiments showed the enzyme incubated for 5 min as a monomer, while that which was incubated for 1 h migrated substantially as dimer. However, the HSCOMT incubated for 1 h in the presence of 60 pM AuNPs and/or AgNPs migrated as a monomer. This indicated that the extension of the incubation period allowed the dimerization of HSCOMT, which exhibited sigmoidal kinetics and higher activity. The presence of NPs impeded the HSCOMT dimerization which decreased the activity. Varying the concentration of SAM suggested that SAM had an allosteric modulatory effect on HSCOMT. Absorption spectroscopy indicated adsorption of HSCOMT on the gold and silver NP surfaces and the formation of NPs-HSCOMT corona. Fluorescence spectroscopy showed that the interaction of HSCOMT with both gold and silver NPs was governed by a static quenching mechanism, implying the formation of a non-fluorescent fluorophore-NP complex at the ground state. Further fluorometric analyses indicated that both gold and silver NPs had contact with Trp143; that the interactions were spontaneous and were driven by electrostatic interactions. Fourier transform infrared spectroscopic studies showed the adsorption of HSCOMT of the NPs surfaces to cause relaxation of the enzyme’s B-sheet structures. Molecular docking studies indicated involvement of largely hydrophilic amino acids, with the interacting distances of less than 3.5A. These findings signify the potential of nanotechnology in the control of COMT catalytic activity for the management of the COMT-related disorders. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
Introduction to the special issue: applied critical realism in the social sciences
- Authors: Price, Leigh , Martin, Lee
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392133 , vital:68724 , xlink:href="https://doi.org/10.1080/14767430.2018.1468148"
- Description: The aim of our initial call for papers was to encourage the submission of exemplars of applied work, reflections on the use of critical realism, and metatheoretical developments. We were not disappointed, and we are therefore pleased to present this collection of five articles which advance our understanding of critical realism in practice. The book review in this issue further extends the collection, as it summarizes several examples of applied critical realist work. As one would expect of such a collection, there are a variety of disciplines represented, from business studies, to marketing, psychology, law and education. In this editorial, we provide an overview of the (concrete universal) trends of current applications of critical realism of which these articles are (concrete singular, and therefore unique) instantiations. Finally, we provide a brief introduction to each paper. We expect that the audience for this issue may be broader than, though still include, the usual readership of Journal of Critical Realism. Specifically, we expect to attract early career researchers who are new to critical realist ideas, and people whose primary interest is directed at one of the disciplines represented, rather than critical realism per se. For this reason, at the risk of repetition, we have allowed several of the authors to outline the aspects of critical realism that are relevant to their paper.
- Full Text:
- Date Issued: 2018
- Authors: Price, Leigh , Martin, Lee
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392133 , vital:68724 , xlink:href="https://doi.org/10.1080/14767430.2018.1468148"
- Description: The aim of our initial call for papers was to encourage the submission of exemplars of applied work, reflections on the use of critical realism, and metatheoretical developments. We were not disappointed, and we are therefore pleased to present this collection of five articles which advance our understanding of critical realism in practice. The book review in this issue further extends the collection, as it summarizes several examples of applied critical realist work. As one would expect of such a collection, there are a variety of disciplines represented, from business studies, to marketing, psychology, law and education. In this editorial, we provide an overview of the (concrete universal) trends of current applications of critical realism of which these articles are (concrete singular, and therefore unique) instantiations. Finally, we provide a brief introduction to each paper. We expect that the audience for this issue may be broader than, though still include, the usual readership of Journal of Critical Realism. Specifically, we expect to attract early career researchers who are new to critical realist ideas, and people whose primary interest is directed at one of the disciplines represented, rather than critical realism per se. For this reason, at the risk of repetition, we have allowed several of the authors to outline the aspects of critical realism that are relevant to their paper.
- Full Text:
- Date Issued: 2018
Literary representations of Zimbabwean migrants’ lives in selected texts
- Authors: Mpofu, Tarisai
- Date: 2018
- Subjects: Human rights -- Zimbabwe , Homelessness in literature , African diaspora in literature
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3402 , vital:43340
- Description: It has been nearly two decades since Zimbabwe has been engulfed in both political and economic crises which have had untold hardships to the majority of ordinary people. As the hardships worsened it pushed Zimbabweans to migrate to “greener pastures” as a survival strategy. Due to the sheer numbers of people who left the country, migration became a social phenomenon in the country that even literary writers also explored. It is the purpose of this study to analyse literary reactions to migration in Zimbabwe from the turn of the new millennium to date, with particular reference to selected Zimbabwean fiction in the form of the short story and novel. The dissertation examines how Zimbabwean literature represents life in Zimbabwe in the context of this economic malaise that emerged after the year 2000 and the resultant lives of migrants who left the country as a result of this political and economic crisis. Similar to the majority of African literatures, Zimbabwean literature emerges from specific historical events and this study therefore sought to describe literary representations of people’s responses to the crisis and the life of Zimbabwean migrants in the margins of host communities. This study reveals the intricate relationship between literary responses and the conditions that most migrants found themselves in especially as they fled the country and what obtained in host countries. , Thesis (MA) -- Faculty of Humanities, Social Sciences and Law, 2018
- Full Text:
- Date Issued: 2018
- Authors: Mpofu, Tarisai
- Date: 2018
- Subjects: Human rights -- Zimbabwe , Homelessness in literature , African diaspora in literature
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3402 , vital:43340
- Description: It has been nearly two decades since Zimbabwe has been engulfed in both political and economic crises which have had untold hardships to the majority of ordinary people. As the hardships worsened it pushed Zimbabweans to migrate to “greener pastures” as a survival strategy. Due to the sheer numbers of people who left the country, migration became a social phenomenon in the country that even literary writers also explored. It is the purpose of this study to analyse literary reactions to migration in Zimbabwe from the turn of the new millennium to date, with particular reference to selected Zimbabwean fiction in the form of the short story and novel. The dissertation examines how Zimbabwean literature represents life in Zimbabwe in the context of this economic malaise that emerged after the year 2000 and the resultant lives of migrants who left the country as a result of this political and economic crisis. Similar to the majority of African literatures, Zimbabwean literature emerges from specific historical events and this study therefore sought to describe literary representations of people’s responses to the crisis and the life of Zimbabwean migrants in the margins of host communities. This study reveals the intricate relationship between literary responses and the conditions that most migrants found themselves in especially as they fled the country and what obtained in host countries. , Thesis (MA) -- Faculty of Humanities, Social Sciences and Law, 2018
- Full Text:
- Date Issued: 2018
Low symmetric metallophthalocyanine modified electrode via click chemistry for simultaneous detection of heavy metals
- Fomo, Gertrude, Nwaji, Njemuwa, Nyokong, Tebello
- Authors: Fomo, Gertrude , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187914 , vital:44709 , xlink:href="https://doi.org/10.1016/j.jelechem.2018.02.016"
- Description: Beside different methods and materials used to develop electrochemical sensors, the modification of the electrode using click reaction based on metallophthalocyanine (MPc) compounds are shown to improve the stability and sensitivity of the sensor. This work reported the development of electrochemical sensor for mercury (II), Lead (II), copper (II) and cadmium (II) ions detection based on the synthesized novel low symmetry alkyne terminated cobalt Phthalocyanine (CoPc) derivative. Differential pulse stripping voltammetry (DPSV) technique was employed for the first time in simultaneous determination of trace levels of the above metal ions using modified glassy carbon electrode (GCE) via click chemistry. Under the optimum experimental conditions, the anodic peak current is proportional to the concentrations of metal ions over a wide range of 0 to 0.1 mM with nanolevel detection limit of 81.94, 327.71, 55.87 and 347.06 nM and the sensitivity of 866.23 ± 5.48, 215.82 ± 2.16, 1979.48 ± 11.47 and 204.50 ± 1.10 μA/mM for Hg(II), Cu(II), Pb(II) and Cd(II), respectively. The selectivity of the clicked-CoPc modified GCE toward Hg(II), Cu(II), Pb(II), Cd(II) present no interference from these metals ions. The fabricated electrochemical sensor exhibited very good electrochemical properties such as good reproducibility, stability, reusability and is suitable for the detection of heavy metal ions in tap water in our laboratory.
- Full Text:
- Date Issued: 2018
- Authors: Fomo, Gertrude , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187914 , vital:44709 , xlink:href="https://doi.org/10.1016/j.jelechem.2018.02.016"
- Description: Beside different methods and materials used to develop electrochemical sensors, the modification of the electrode using click reaction based on metallophthalocyanine (MPc) compounds are shown to improve the stability and sensitivity of the sensor. This work reported the development of electrochemical sensor for mercury (II), Lead (II), copper (II) and cadmium (II) ions detection based on the synthesized novel low symmetry alkyne terminated cobalt Phthalocyanine (CoPc) derivative. Differential pulse stripping voltammetry (DPSV) technique was employed for the first time in simultaneous determination of trace levels of the above metal ions using modified glassy carbon electrode (GCE) via click chemistry. Under the optimum experimental conditions, the anodic peak current is proportional to the concentrations of metal ions over a wide range of 0 to 0.1 mM with nanolevel detection limit of 81.94, 327.71, 55.87 and 347.06 nM and the sensitivity of 866.23 ± 5.48, 215.82 ± 2.16, 1979.48 ± 11.47 and 204.50 ± 1.10 μA/mM for Hg(II), Cu(II), Pb(II) and Cd(II), respectively. The selectivity of the clicked-CoPc modified GCE toward Hg(II), Cu(II), Pb(II), Cd(II) present no interference from these metals ions. The fabricated electrochemical sensor exhibited very good electrochemical properties such as good reproducibility, stability, reusability and is suitable for the detection of heavy metal ions in tap water in our laboratory.
- Full Text:
- Date Issued: 2018
Mechanisms and indicators for assessing the impact of biofuel feedstock production on ecosystem services
- Gasparatos, Alexandros, Romeu-Dalmau, Carla, von Maltitz, Graham P, Johnson, Francis X, Shackleton, Charlie M, Jarzebski, Marcin P, Jumbe, Charles, Ochieng, Caroline, Mudombi, Shakespear, Nyambane, Anne, Willis, Katherine J
- Authors: Gasparatos, Alexandros , Romeu-Dalmau, Carla , von Maltitz, Graham P , Johnson, Francis X , Shackleton, Charlie M , Jarzebski, Marcin P , Jumbe, Charles , Ochieng, Caroline , Mudombi, Shakespear , Nyambane, Anne , Willis, Katherine J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181368 , vital:43727 , xlink:href="https://doi.org/10.1016/j.biombioe.2018.01.024"
- Description: Biofuel feedstock production can be a significant driver of landscape modification, ecosystem change and biodiversity loss. There is growing body of literature that shows how biofuel landscapes provide various ecosystem services (e.g., feedstock for fuel, carbon sequestration) and compromise other ecosystem services (e.g., food, freshwater services). These effects are context-specific and depend largely on prior land use conditions and feedstock production practices. Changes in the flow of ecosystem services due to the conversion of natural and agricultural areas can have ripple effects on human wellbeing. Despite some recent attempts to apply to biofuel settings concepts and methods rooted in the ecosystem services literature, this is the exception rather than the rule within both the biofuel and the ecosystem services research communities. This paper synthesizes the current knowledge about the impact of biofuels on ecosystem services. It focuses especially on the feedstock production phase and outlines the main mechanisms through which landscape conversion affects the provisions of ecosystem services. It proposes conceptually coherent indicators to reflect these mechanisms and offers a critical discussion of key issues at the interface of biofuels and ecosystem services.
- Full Text:
- Date Issued: 2018
- Authors: Gasparatos, Alexandros , Romeu-Dalmau, Carla , von Maltitz, Graham P , Johnson, Francis X , Shackleton, Charlie M , Jarzebski, Marcin P , Jumbe, Charles , Ochieng, Caroline , Mudombi, Shakespear , Nyambane, Anne , Willis, Katherine J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181368 , vital:43727 , xlink:href="https://doi.org/10.1016/j.biombioe.2018.01.024"
- Description: Biofuel feedstock production can be a significant driver of landscape modification, ecosystem change and biodiversity loss. There is growing body of literature that shows how biofuel landscapes provide various ecosystem services (e.g., feedstock for fuel, carbon sequestration) and compromise other ecosystem services (e.g., food, freshwater services). These effects are context-specific and depend largely on prior land use conditions and feedstock production practices. Changes in the flow of ecosystem services due to the conversion of natural and agricultural areas can have ripple effects on human wellbeing. Despite some recent attempts to apply to biofuel settings concepts and methods rooted in the ecosystem services literature, this is the exception rather than the rule within both the biofuel and the ecosystem services research communities. This paper synthesizes the current knowledge about the impact of biofuels on ecosystem services. It focuses especially on the feedstock production phase and outlines the main mechanisms through which landscape conversion affects the provisions of ecosystem services. It proposes conceptually coherent indicators to reflect these mechanisms and offers a critical discussion of key issues at the interface of biofuels and ecosystem services.
- Full Text:
- Date Issued: 2018
Media portrayal of gender based violence: a perception study in Uitenhage, Eastern Cape South Africa 2
- Oladimeji Olawumi Kate https://orcid.org/0000-0002-6577-0140
- Authors: Oladimeji Olawumi Kate https://orcid.org/0000-0002-6577-0140
- Date: 2018
- Subjects: Abused women , Mass media -- Eastern Cape -- South Africa , Mass media criticism -- Eastern Cape -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19476 , vital:43131
- Description: Gender based violence (GBV) has become a global menace. The prevalence of this violence against women and children in South Africa reveals that the country is plagued by this horror called GBV. According to the South African police crime statistics, with regards to sexual offences, the SAPS reported 64 419 (2012), 66 197 (2014), 62 226 (2013) and 53 617 (2015) cases. A government survey conducted revealed that men were the main perpetrators of this violence. For example, 76 percent of men in Gauteng, 48 percent in Limpopo and 41 percent in KwaZulu-Natal admitted to perpetrating GBV. These alarming statistics calls for the attention of the media. The media is known to be a powerful tool of influence, however in the process, the media has been criticised to portray violence in ways which can have varying effect on the behaviour of those exposed to it. This study was therefore conducted to investigate the perception of the residents of Uitenhage on the media‘s portrayal of gender based violence against women and children. The mixed method of research was used to obtain data from the participants and respondents which were residents of Uitenhage, in the Eastern Cape, South Africa. Non-probability sampling in the form of purposive sampling was used to select the focus group participants while probability sampling in the form of simple random probability sampling was used to select the respondents with whom the questionnaires were administered to. Quantitative data analysis for questionnaires was done using descriptive statistics and findings were presented in form of tables and pie charts while qualitative data analysis for the focus group discussions was done using thematic analysis. A final sample of 257 valid responses were analysed, representing 80 percent response rate, three focus group discussions were also analysed. The study revealed that all the participants and respondents are exposed to more than one medium of mass communication, however participants and respondents opined that the media has both positive and negative effect on different individuals. The study also demonstrated that there is an association between people‘s exposure to the media and their violent behaviour which is attributed to the messages conveyed by the media. The study recommends amongst others that the media should take a more proactive approach to the issue of VAW. , Thesis (PhD) (Communication) -- University of Fort Hare, 2018
- Full Text:
- Date Issued: 2018
- Authors: Oladimeji Olawumi Kate https://orcid.org/0000-0002-6577-0140
- Date: 2018
- Subjects: Abused women , Mass media -- Eastern Cape -- South Africa , Mass media criticism -- Eastern Cape -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19476 , vital:43131
- Description: Gender based violence (GBV) has become a global menace. The prevalence of this violence against women and children in South Africa reveals that the country is plagued by this horror called GBV. According to the South African police crime statistics, with regards to sexual offences, the SAPS reported 64 419 (2012), 66 197 (2014), 62 226 (2013) and 53 617 (2015) cases. A government survey conducted revealed that men were the main perpetrators of this violence. For example, 76 percent of men in Gauteng, 48 percent in Limpopo and 41 percent in KwaZulu-Natal admitted to perpetrating GBV. These alarming statistics calls for the attention of the media. The media is known to be a powerful tool of influence, however in the process, the media has been criticised to portray violence in ways which can have varying effect on the behaviour of those exposed to it. This study was therefore conducted to investigate the perception of the residents of Uitenhage on the media‘s portrayal of gender based violence against women and children. The mixed method of research was used to obtain data from the participants and respondents which were residents of Uitenhage, in the Eastern Cape, South Africa. Non-probability sampling in the form of purposive sampling was used to select the focus group participants while probability sampling in the form of simple random probability sampling was used to select the respondents with whom the questionnaires were administered to. Quantitative data analysis for questionnaires was done using descriptive statistics and findings were presented in form of tables and pie charts while qualitative data analysis for the focus group discussions was done using thematic analysis. A final sample of 257 valid responses were analysed, representing 80 percent response rate, three focus group discussions were also analysed. The study revealed that all the participants and respondents are exposed to more than one medium of mass communication, however participants and respondents opined that the media has both positive and negative effect on different individuals. The study also demonstrated that there is an association between people‘s exposure to the media and their violent behaviour which is attributed to the messages conveyed by the media. The study recommends amongst others that the media should take a more proactive approach to the issue of VAW. , Thesis (PhD) (Communication) -- University of Fort Hare, 2018
- Full Text:
- Date Issued: 2018
More than just fields: Reframing deagrarianisation in landscapes and livelihoods
- Hebinck, Paul, Mtati, Nosiseko, Shackleton, Charlie M
- Authors: Hebinck, Paul , Mtati, Nosiseko , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180322 , vital:43353 , xlink:href="https://doi.org/10.1016/j.jrurstud.2018.01.004"
- Description: This paper discusses the emergent properties of deagrarianisation processes in two villages in the central Eastern Cape, South Africa. The claim of is that much of the deagrarianisation literature and debate does not acknowledge the importance of landscapes and the interaction between their constituent elements, notably people, forests, grasslands, fields, grazing lands, open spaces, built environments and homesteads, all of which contribute to shaping and, in turn, are shaped by livelihoods. Conceptualising a landscape as a spatial entity and associated assemblage of practices, discourses and history, this paper dissects the landscape in terms of land uses for residential and cultural purposes, growing, grazing and gathering. These land use categories together represent the rural domain to which the villagers are attached as a place and a home. Their use of the land is not necessarily oriented to fully exploring its productive potential. The article explores the transformation from a productive landscape to one which largely hinges on consumption. The blurring of boundaries between the formally designated land use categories signifies the transformations occurring in many of the rural areas in the former homelands of South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Hebinck, Paul , Mtati, Nosiseko , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180322 , vital:43353 , xlink:href="https://doi.org/10.1016/j.jrurstud.2018.01.004"
- Description: This paper discusses the emergent properties of deagrarianisation processes in two villages in the central Eastern Cape, South Africa. The claim of is that much of the deagrarianisation literature and debate does not acknowledge the importance of landscapes and the interaction between their constituent elements, notably people, forests, grasslands, fields, grazing lands, open spaces, built environments and homesteads, all of which contribute to shaping and, in turn, are shaped by livelihoods. Conceptualising a landscape as a spatial entity and associated assemblage of practices, discourses and history, this paper dissects the landscape in terms of land uses for residential and cultural purposes, growing, grazing and gathering. These land use categories together represent the rural domain to which the villagers are attached as a place and a home. Their use of the land is not necessarily oriented to fully exploring its productive potential. The article explores the transformation from a productive landscape to one which largely hinges on consumption. The blurring of boundaries between the formally designated land use categories signifies the transformations occurring in many of the rural areas in the former homelands of South Africa.
- Full Text:
- Date Issued: 2018
Morphological, genetic and biological characterisation of a novel alphabaculovirus isolated from Cryptophlebia peltastica (Lepidoptera: Tortricidae)
- Marsberg, Tamryn, Jukes, Michael, Krejmer-Rabalska, Martyna, Rabalski, Lukasz, Knox, Caroline, Moore, Sean D, Hill, Martin P, Szewczyk, Boguslaw
- Authors: Marsberg, Tamryn , Jukes, Michael , Krejmer-Rabalska, Martyna , Rabalski, Lukasz , Knox, Caroline , Moore, Sean D , Hill, Martin P , Szewczyk, Boguslaw
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419330 , vital:71635 , xlink:href="https://doi.org/10.1016/j.jip.2018.08.006"
- Description: Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115 728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC50 value of 6.46 × 103 OBs/ml and an LC90 value of 2.46 × 105 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Marsberg, Tamryn , Jukes, Michael , Krejmer-Rabalska, Martyna , Rabalski, Lukasz , Knox, Caroline , Moore, Sean D , Hill, Martin P , Szewczyk, Boguslaw
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419330 , vital:71635 , xlink:href="https://doi.org/10.1016/j.jip.2018.08.006"
- Description: Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115 728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC50 value of 6.46 × 103 OBs/ml and an LC90 value of 2.46 × 105 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2018
Nontimber forest products as ecological and biocultural keystone species
- Shackleton, Charlie M, Ticktin, Tamara, Cunningham, Anthony B
- Authors: Shackleton, Charlie M , Ticktin, Tamara , Cunningham, Anthony B
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180388 , vital:43359 , xlink:href="https://doi.org/10.5751/ES-10469-230422"
- Description: Nontimber forests products (NTFPs) are the mainstay of rural livelihoods and local economies the world over. As such they are of interest to a wide disciplinary range of researchers and development and government agencies seeking to promote livelihoods, incomes, and ecologically sustainable practices. With the attention on the various human uses of NTFPs, their role and networks in the broader biological communities in which they are located are frequently overlooked. Harvesting of many NTFPs has effects not only at the organism and population scales, but also on co-occurring species, some of which may also be NTFPs. Thus, reduction or loss of one NTFP population or species in a specific area may have cascade effects on other NTFP species, including those used for cultural purposes. We illustrate the little appreciated importance of NTFPs in broader ecological and social systems by assessing and illustrating the importance of NTFP species as ecological or biocultural keystones in providing regulating and supporting ecological services to other species and cultural services to people. We present a number of examples where NTFP species act as keystones in ecological and cultural systems, including food, pollination and dispersal, animal health, nutrients, shelter and protection, and cultural symbolism, most of which have not been considered by NTFP researchers and practitioners. From these examples we distill six propositions regarding NTFPs and discuss the value of recognizing some NTFPs as biocultural keystones to acknowledge and highlight their roles at broader scales.
- Full Text:
- Date Issued: 2018
- Authors: Shackleton, Charlie M , Ticktin, Tamara , Cunningham, Anthony B
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180388 , vital:43359 , xlink:href="https://doi.org/10.5751/ES-10469-230422"
- Description: Nontimber forests products (NTFPs) are the mainstay of rural livelihoods and local economies the world over. As such they are of interest to a wide disciplinary range of researchers and development and government agencies seeking to promote livelihoods, incomes, and ecologically sustainable practices. With the attention on the various human uses of NTFPs, their role and networks in the broader biological communities in which they are located are frequently overlooked. Harvesting of many NTFPs has effects not only at the organism and population scales, but also on co-occurring species, some of which may also be NTFPs. Thus, reduction or loss of one NTFP population or species in a specific area may have cascade effects on other NTFP species, including those used for cultural purposes. We illustrate the little appreciated importance of NTFPs in broader ecological and social systems by assessing and illustrating the importance of NTFP species as ecological or biocultural keystones in providing regulating and supporting ecological services to other species and cultural services to people. We present a number of examples where NTFP species act as keystones in ecological and cultural systems, including food, pollination and dispersal, animal health, nutrients, shelter and protection, and cultural symbolism, most of which have not been considered by NTFP researchers and practitioners. From these examples we distill six propositions regarding NTFPs and discuss the value of recognizing some NTFPs as biocultural keystones to acknowledge and highlight their roles at broader scales.
- Full Text:
- Date Issued: 2018