Pressurized hot water extraction of nutraceuticals and organic pollutants from medicinal plants
- Authors: Mokgadi, Janes
- Date: 2011
- Subjects: Functional foods Medicinal plants -- Biotechnology Extraction (Chemistry) Goldenseal Botanical pesticides Sorbents Organic solvents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4338 , http://hdl.handle.net/10962/d1004999
- Description: This thesis explores the robustness and the versatility of pressurized hot water extraction (PHWE) for a variety of analytes and matrices. Applications discussed include: selective extraction of alkaloids in goldenseal followed by their degradation studies; in-cell clean-up of pesticides in medicinal plants employing custom made molecularly imprinted polymers (MIPs) sorbents; in-cell pre-concentration followed by desorption of aflatoxins in plants with MIPs; desorption of pesticides from electrospun nanofiber sorbents; and removal of templates from MIPs sorbents. It was demonstrated that selective extractions could be achieved by just changing the temperature of water while adjusting the pressure. For instance, the alkaloids in goldenseal (hydrastine and berberine), were extracted at 140 °C, 50 bars, 1 mL min⁻¹ in 15 min; organochlorine pesticides from medicinal plants were extracted at 260 °C, 80 bars, 1 mL min-1 in 10 min; while aflatoxins AFG2, AFG1, AFB2 and AFB1 were extracted at 180 °C, 60 bars and a flow rate of 0.5 mL min⁻¹ in 10 min. The selectivity of PHWE was further enhanced by combining it with selective MIPs sorbents at higher temperatutes. In-cell clean-up of interfering chlorophyll was successfully removed from the medicinal plants during pesticides analysis while clean-up of aflatoxins AFG2, AFG1, AFB2 and AFB1 was achieved in two extraction cells connected in series. Ultrasound was also combined with PHWE for extraction of hydrastine and berberine at 80 °C and 40 bars in 30 min. PHWE was further evaluated for removal of templates from quercetin, phthalocynine and chlorophyll MIPs. The templates were thoroughly washed off their MIPs within 70 min with PHWE compared to over 8 h for Soxhlet and ultrasound assisted extraction. Pesticides were also desorbed from electrospun nanofibers at 260 °C, 80 bars in 10 min employing only water at 0.5 mL min⁻¹. In the light of green chemistry, the decrease in the usage of organic solvents was 100%, resulting in no organic solvent waste.
- Full Text:
- Authors: Mokgadi, Janes
- Date: 2011
- Subjects: Functional foods Medicinal plants -- Biotechnology Extraction (Chemistry) Goldenseal Botanical pesticides Sorbents Organic solvents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4338 , http://hdl.handle.net/10962/d1004999
- Description: This thesis explores the robustness and the versatility of pressurized hot water extraction (PHWE) for a variety of analytes and matrices. Applications discussed include: selective extraction of alkaloids in goldenseal followed by their degradation studies; in-cell clean-up of pesticides in medicinal plants employing custom made molecularly imprinted polymers (MIPs) sorbents; in-cell pre-concentration followed by desorption of aflatoxins in plants with MIPs; desorption of pesticides from electrospun nanofiber sorbents; and removal of templates from MIPs sorbents. It was demonstrated that selective extractions could be achieved by just changing the temperature of water while adjusting the pressure. For instance, the alkaloids in goldenseal (hydrastine and berberine), were extracted at 140 °C, 50 bars, 1 mL min⁻¹ in 15 min; organochlorine pesticides from medicinal plants were extracted at 260 °C, 80 bars, 1 mL min-1 in 10 min; while aflatoxins AFG2, AFG1, AFB2 and AFB1 were extracted at 180 °C, 60 bars and a flow rate of 0.5 mL min⁻¹ in 10 min. The selectivity of PHWE was further enhanced by combining it with selective MIPs sorbents at higher temperatutes. In-cell clean-up of interfering chlorophyll was successfully removed from the medicinal plants during pesticides analysis while clean-up of aflatoxins AFG2, AFG1, AFB2 and AFB1 was achieved in two extraction cells connected in series. Ultrasound was also combined with PHWE for extraction of hydrastine and berberine at 80 °C and 40 bars in 30 min. PHWE was further evaluated for removal of templates from quercetin, phthalocynine and chlorophyll MIPs. The templates were thoroughly washed off their MIPs within 70 min with PHWE compared to over 8 h for Soxhlet and ultrasound assisted extraction. Pesticides were also desorbed from electrospun nanofibers at 260 °C, 80 bars in 10 min employing only water at 0.5 mL min⁻¹. In the light of green chemistry, the decrease in the usage of organic solvents was 100%, resulting in no organic solvent waste.
- Full Text:
Privatisation, human rights and security: reflections on the draft international convention on regulation, oversight and monitoring of private military and security companies
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128800 , vital:36160 , http://dx.doi.org/10.4314/ldd.v15i1.3
- Description: Efforts to establish regulatory frameworks for private military/security companies (PMSCs), driven by public security concerns as well as private interests of the companies themselves, have yielded a number of soft law instruments. Unfortunately, most of these instruments are conditioned by the underlying interests of their promulgators and have therefore failed to establish universally acceptable regulatory standards.
- Full Text:
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128800 , vital:36160 , http://dx.doi.org/10.4314/ldd.v15i1.3
- Description: Efforts to establish regulatory frameworks for private military/security companies (PMSCs), driven by public security concerns as well as private interests of the companies themselves, have yielded a number of soft law instruments. Unfortunately, most of these instruments are conditioned by the underlying interests of their promulgators and have therefore failed to establish universally acceptable regulatory standards.
- Full Text:
Probing the biocompatibility of biomedical interfaces using the Quartz Crystal Microbalance with Dissipation
- Authors: Cromhout, Mary
- Date: 2011
- Subjects: Biomedical materials , Nanostructured materials , Biomedical engineering , Quartz crystal microbalances , Blood proteins , Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4102 , http://hdl.handle.net/10962/d1010660
- Description: The biomedical application of nanotechnology has come into the spotlight, with the promise of ‘personalised’ therapeutics that couple early diagnosis with targeted therapeutic activity. Due to the rapid growth of the biomedical applications of nanoparticles, along with the lack of understanding concerning their interactions with biomolecules, there is a pressing need for the development of standard methods directed at investigating the effect of introducing these unique particles into the human body. The central aim of this research is to establish a platform directed at assessing the biological fate of pioneering therapeutic particulate agents, such as metallophthalocyanines (MPcs) and multi-walled carbon nanotubes (FMWCNTs). In particular, we proposed, that Quartz Crystal Microbalance with Dissipation (QCM-D) technology may be employed to assess the composition of blood protein corona deposited on the therapeutic surface, and subsequently assess the biocompatibility of such particles. The proposed method of protein detection utilises the nanogram sensitivity of QCM-D technology to monitor highly specific antibody-antigen interactions. In particular those interactions which occur when probe antibodies are used to detect adsorbed blood proteins deposited on target particle-modified sensor surfaces. Protein detection analysis was directed toward identification of surface bound human serum albumin, complement factor C3c, and human plasma fibrinogen. Preliminary analysis of generic biomedical surfaces indicated human serum albumin demonstrates a higher binding affinity towards positively charged surfaces (i.e. cysteamine self-assembled monolayer), followed by hydrophobic surfaces. Detection of complement C3c, corresponded with literature, where lower levels were detected on negatively charged surfaces (i.e. mercapto undecanoic acid self-assembled monolayer), and higher levels of more hydrophobic surfaces (i.e. 11-amino undecane thiol self-assembled monolayer). Human plasma fibrinogen was observed to favour hydrophilic over hydrophobic self-assembled monolayer surfaces, which was in accordance with literature. Application of the proposed protein detection method for biocompatibility analysis of target therapeutic molecules, namely metallophthalocyanines and acid functionalised multi-walled carbon nanotubes, demonstrated a dependence on modified-surface film characteristics, such as surface charge and topography with regards to human serum albumin and human plasma fibrinogen analysis representing new insights into their potential biomolecular interactions The highest levels of detected human serum albumin and complement C3c were detected on the GePcSmix-modified surfaces. AlPcSmix-modified surfaces analysis suggested the highest levels of human plasma fibrinogen. Two methods of acid functionalisation were employed, using both nitric and sulphuric acid, and pure nitric acid. A general increase in detected human serum albumin, corresponding with an increase in functionalisation time, was observed. Complement C3c detection suggested an increase in deposited complement C3c, with increasing functionalisation time, when assessing nitric acid functionalised multi-walled carbon nanotubes, and a decrease, with increasing functionalisation time, when assessing nitric and sulphuric acid functionalised multi-walled carbon nanotubes. Analysis of human plasma fibrinogen was inconclusive, as were cytotoxicity experiments utilising MCF-7 cells in the presence of metallophthalocyanine complexes, raising simultaneously important considerations for their application and study. In the first such detailed examination of its kind it was concluded that the proposed method of protein detection, using QCM-D, allows for the rudimentary but rapid means of analysis of select protein corona deposited on particulate biomedical surfaces.
- Full Text:
- Authors: Cromhout, Mary
- Date: 2011
- Subjects: Biomedical materials , Nanostructured materials , Biomedical engineering , Quartz crystal microbalances , Blood proteins , Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4102 , http://hdl.handle.net/10962/d1010660
- Description: The biomedical application of nanotechnology has come into the spotlight, with the promise of ‘personalised’ therapeutics that couple early diagnosis with targeted therapeutic activity. Due to the rapid growth of the biomedical applications of nanoparticles, along with the lack of understanding concerning their interactions with biomolecules, there is a pressing need for the development of standard methods directed at investigating the effect of introducing these unique particles into the human body. The central aim of this research is to establish a platform directed at assessing the biological fate of pioneering therapeutic particulate agents, such as metallophthalocyanines (MPcs) and multi-walled carbon nanotubes (FMWCNTs). In particular, we proposed, that Quartz Crystal Microbalance with Dissipation (QCM-D) technology may be employed to assess the composition of blood protein corona deposited on the therapeutic surface, and subsequently assess the biocompatibility of such particles. The proposed method of protein detection utilises the nanogram sensitivity of QCM-D technology to monitor highly specific antibody-antigen interactions. In particular those interactions which occur when probe antibodies are used to detect adsorbed blood proteins deposited on target particle-modified sensor surfaces. Protein detection analysis was directed toward identification of surface bound human serum albumin, complement factor C3c, and human plasma fibrinogen. Preliminary analysis of generic biomedical surfaces indicated human serum albumin demonstrates a higher binding affinity towards positively charged surfaces (i.e. cysteamine self-assembled monolayer), followed by hydrophobic surfaces. Detection of complement C3c, corresponded with literature, where lower levels were detected on negatively charged surfaces (i.e. mercapto undecanoic acid self-assembled monolayer), and higher levels of more hydrophobic surfaces (i.e. 11-amino undecane thiol self-assembled monolayer). Human plasma fibrinogen was observed to favour hydrophilic over hydrophobic self-assembled monolayer surfaces, which was in accordance with literature. Application of the proposed protein detection method for biocompatibility analysis of target therapeutic molecules, namely metallophthalocyanines and acid functionalised multi-walled carbon nanotubes, demonstrated a dependence on modified-surface film characteristics, such as surface charge and topography with regards to human serum albumin and human plasma fibrinogen analysis representing new insights into their potential biomolecular interactions The highest levels of detected human serum albumin and complement C3c were detected on the GePcSmix-modified surfaces. AlPcSmix-modified surfaces analysis suggested the highest levels of human plasma fibrinogen. Two methods of acid functionalisation were employed, using both nitric and sulphuric acid, and pure nitric acid. A general increase in detected human serum albumin, corresponding with an increase in functionalisation time, was observed. Complement C3c detection suggested an increase in deposited complement C3c, with increasing functionalisation time, when assessing nitric acid functionalised multi-walled carbon nanotubes, and a decrease, with increasing functionalisation time, when assessing nitric and sulphuric acid functionalised multi-walled carbon nanotubes. Analysis of human plasma fibrinogen was inconclusive, as were cytotoxicity experiments utilising MCF-7 cells in the presence of metallophthalocyanine complexes, raising simultaneously important considerations for their application and study. In the first such detailed examination of its kind it was concluded that the proposed method of protein detection, using QCM-D, allows for the rudimentary but rapid means of analysis of select protein corona deposited on particulate biomedical surfaces.
- Full Text:
Prof Nyokong receives another Science award
- Authors: Matiwana, Zamuxolo
- Date: 2011
- Subjects: Nyokong, Tebello , International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM)
- Language: English
- Type: Article , text
- Identifier: vital:7182 , http://hdl.handle.net/10962/d1006267 , Nyokong, Tebello
- Description: The Rhodes University professor of Medicinal Chemistry and Nanotechnology, Tebello Nyokong, says the Award for her Scientific Achievements by the International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM) is an honour, especially since it is awarded in memory of the centenary of the first Nobel Prize in Chemistry awarded to a woman: Marie Curie.
- Full Text:
- Authors: Matiwana, Zamuxolo
- Date: 2011
- Subjects: Nyokong, Tebello , International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM)
- Language: English
- Type: Article , text
- Identifier: vital:7182 , http://hdl.handle.net/10962/d1006267 , Nyokong, Tebello
- Description: The Rhodes University professor of Medicinal Chemistry and Nanotechnology, Tebello Nyokong, says the Award for her Scientific Achievements by the International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM) is an honour, especially since it is awarded in memory of the centenary of the first Nobel Prize in Chemistry awarded to a woman: Marie Curie.
- Full Text:
Proposed South African management framework for the implementation of the International Convention for the Control and Management of Ships' Ballast Water and Sediments
- Authors: Nolting, Janine
- Date: 2011
- Subjects: Ships -- Fouling Discharge of ballast water -- Environmental aspects International Convention for the Control and Management of Ships' Ballast Water and Sediments Nonindigenous aquatic pests -- Law and legislation Marine fouling organisms -- Law and legislation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:786 , http://hdl.handle.net/10962/d1003907
- Description: South Africa, strategically situated at the southern tip of Africa, is edged on three sides by almost 3000 km of coastline surrounded by the Indian Ocean and the Atlantic Ocean (South African Tourism, 2011). This vast ocean expanse is responsible for conveying approximately 96% of South Africa’s exports (Brand South Africa, 2011). Despite the positive economic effects of the shipping industry, translocation of harmful organisms and pathogens via ballast water and sediments inside ballast water tanks has far reaching global environmental (and economic) impacts (Oliviera, 2008:1; David and Gollasch, 2008:1966). Ballast water is the water that is taken on in order to manage the draft of the ship, to help with propulsion, manoeuvrability, trim control, list and stability (Oliviera, 2008:2). The discharge of ballast water into the world’s oceans has resulted in the transfer of ecologically harmful sea-life into non-native environments (IMO, 2011), resulting in major environmental threats to our oceans (Bax, Williamson, Aguero, Gonzalez and Geeves, 2003:313). Various international documents have been developed to deal with the ballast water issue, culminating in the introduction of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (“the Convention”) in 2004. The Convention aims at achieving a reduction in the transfer and subsequent impacts of aquatic organisms via the ballast water and sediment of ships. On a local level, South Africa does not have direct legislation or regulations dealing with ballast water (Duncan, 2007:34) and relies on the combination of a number of pieces of legislation relating to environmental management, coastal management, biodiversity, alien invasive species control, port control and ship safety (National Environmental Management Act, 1998, National Environmental Management: Biodiversity Act, 2004, National Environmental Management: Integrated Coastal Management Act, 2009, National Ports Act, 2005 and Merchant Shipping Act, 1951). Although the Convention was ratified by South Africa in 2008 (Department of International Relations and Cooperation, 2011) it is still not in force and there still exists no other consolidated legal mechanism through which ballast water is managed. This research has investigated the various roles, responsibilities and mandates of South African competent authorities under the aforementioned legislation in managing ballast water, and has determined that there is definite legislative and institutional fragmentation as well as overlaps. A comparative analysis of management frameworks developed both locally and internationally was conducted in order to develop a management framework for ballast water management in South Africa. Various legislative, institutional and functional aspects were identified and adapted for inclusion in a South African management framework. A co-ordinated approach to ballast water management has been developed in the management framework which is anticipated to result in more definitive roles and responsibilities of the various South African departments involved in the management of ballast water and implementation of the Convention.
- Full Text:
- Authors: Nolting, Janine
- Date: 2011
- Subjects: Ships -- Fouling Discharge of ballast water -- Environmental aspects International Convention for the Control and Management of Ships' Ballast Water and Sediments Nonindigenous aquatic pests -- Law and legislation Marine fouling organisms -- Law and legislation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:786 , http://hdl.handle.net/10962/d1003907
- Description: South Africa, strategically situated at the southern tip of Africa, is edged on three sides by almost 3000 km of coastline surrounded by the Indian Ocean and the Atlantic Ocean (South African Tourism, 2011). This vast ocean expanse is responsible for conveying approximately 96% of South Africa’s exports (Brand South Africa, 2011). Despite the positive economic effects of the shipping industry, translocation of harmful organisms and pathogens via ballast water and sediments inside ballast water tanks has far reaching global environmental (and economic) impacts (Oliviera, 2008:1; David and Gollasch, 2008:1966). Ballast water is the water that is taken on in order to manage the draft of the ship, to help with propulsion, manoeuvrability, trim control, list and stability (Oliviera, 2008:2). The discharge of ballast water into the world’s oceans has resulted in the transfer of ecologically harmful sea-life into non-native environments (IMO, 2011), resulting in major environmental threats to our oceans (Bax, Williamson, Aguero, Gonzalez and Geeves, 2003:313). Various international documents have been developed to deal with the ballast water issue, culminating in the introduction of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (“the Convention”) in 2004. The Convention aims at achieving a reduction in the transfer and subsequent impacts of aquatic organisms via the ballast water and sediment of ships. On a local level, South Africa does not have direct legislation or regulations dealing with ballast water (Duncan, 2007:34) and relies on the combination of a number of pieces of legislation relating to environmental management, coastal management, biodiversity, alien invasive species control, port control and ship safety (National Environmental Management Act, 1998, National Environmental Management: Biodiversity Act, 2004, National Environmental Management: Integrated Coastal Management Act, 2009, National Ports Act, 2005 and Merchant Shipping Act, 1951). Although the Convention was ratified by South Africa in 2008 (Department of International Relations and Cooperation, 2011) it is still not in force and there still exists no other consolidated legal mechanism through which ballast water is managed. This research has investigated the various roles, responsibilities and mandates of South African competent authorities under the aforementioned legislation in managing ballast water, and has determined that there is definite legislative and institutional fragmentation as well as overlaps. A comparative analysis of management frameworks developed both locally and internationally was conducted in order to develop a management framework for ballast water management in South Africa. Various legislative, institutional and functional aspects were identified and adapted for inclusion in a South African management framework. A co-ordinated approach to ballast water management has been developed in the management framework which is anticipated to result in more definitive roles and responsibilities of the various South African departments involved in the management of ballast water and implementation of the Convention.
- Full Text:
Prospects for the biological control of submerged macrophytes in South Africa
- Coetzee, Julie A, Bownes, Angela, Martin, Grant D
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452295 , vital:75118 , https://hdl.handle.net/10520/EJC32899
- Description: Historically, biological control efforts against aquatic plants in South Africa have focused on floating species, and as a result, there has been a dearth of research into the invasion and control of submerged macrophytes. With numerous submerged invasive species already established in South Africa, thriving horticultural and aquarium industries, nutrient-rich water systems, and a limited knowledge of the drivers of invasions of submerged macrophytes, South Africa is highly vulnerable to a second phase of aquatic plant problems. Experience gained in the U.S.A. on biological control against submerged weeds, such as hydrilla, Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae) and spiked / Eurasian watermilfoil, Myriophyllum spicatum L. (Haloragaceae), have provided South African researchers with the necessary foundation to initiate programmes against these weeds. Research in South Africa is currently focused on pre-release studies on the biological control of H. verticillata, using an undescribed fly, Hydrellia sp. (Diptera: Ephydridae) and a weevil, Bagous hydrillae O'Brien (Coleoptera: Curculionidae); and on M. spicatum using a North American weevil, Euhrychiopsis lecontei Dietz (Coleoptera: Curculionidae). Feasibility studies into biological control of some incipient submerged weeds are also being conducted, including Brazilian water weed, Egeria densa Planch. (Hydrocharitaceae), Canadian water weed, Elodea canadensis Mitch. (Hydrocharitaceae) and cabomba, Cabomba caroliniana A. Gray (Cabombaceae). Progress with, and potential constraints that may limit these programmes, are discussed.
- Full Text:
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452295 , vital:75118 , https://hdl.handle.net/10520/EJC32899
- Description: Historically, biological control efforts against aquatic plants in South Africa have focused on floating species, and as a result, there has been a dearth of research into the invasion and control of submerged macrophytes. With numerous submerged invasive species already established in South Africa, thriving horticultural and aquarium industries, nutrient-rich water systems, and a limited knowledge of the drivers of invasions of submerged macrophytes, South Africa is highly vulnerable to a second phase of aquatic plant problems. Experience gained in the U.S.A. on biological control against submerged weeds, such as hydrilla, Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae) and spiked / Eurasian watermilfoil, Myriophyllum spicatum L. (Haloragaceae), have provided South African researchers with the necessary foundation to initiate programmes against these weeds. Research in South Africa is currently focused on pre-release studies on the biological control of H. verticillata, using an undescribed fly, Hydrellia sp. (Diptera: Ephydridae) and a weevil, Bagous hydrillae O'Brien (Coleoptera: Curculionidae); and on M. spicatum using a North American weevil, Euhrychiopsis lecontei Dietz (Coleoptera: Curculionidae). Feasibility studies into biological control of some incipient submerged weeds are also being conducted, including Brazilian water weed, Egeria densa Planch. (Hydrocharitaceae), Canadian water weed, Elodea canadensis Mitch. (Hydrocharitaceae) and cabomba, Cabomba caroliniana A. Gray (Cabombaceae). Progress with, and potential constraints that may limit these programmes, are discussed.
- Full Text:
Psoralea margaretiflora (Psoraleeae, Fabaceae): a new species from the Sneeuberg Centre of Floristic Endemism, Eastern Cape, South Africa
- Stirton, Charles H, Clark, Vincent Ralph, Barker, Nigel P, Muasya, A Muthama
- Authors: Stirton, Charles H , Clark, Vincent Ralph , Barker, Nigel P , Muasya, A Muthama
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6543 , http://hdl.handle.net/10962/d1005999
- Description: A new species of Psoralea is described. Psoralea margaretiflora C.H. Stirton & V.R. Clark is endemic to the Sneeuberg Centre of Floristic Endemism, Eastern Cape, South Africa. This resprouter is characterised by its small greenish-white flowers with a small trifid purple nectar patch and translucent veins; 5(–7)-pinnate leaflets; multi-branching erect short seasonal flowering shoots; and tall habit of many stiff bare stems with the seasonal shoots massed at the apex. It is most similar to P. oligophylla Eckl. & Zeyh., a widespread species found in the Eastern Cape. The reseeder P. oligophylla differs in its lax virgate spreading habit with numerous long glaucous seasonal shoots; single stem, 1(–3)- glaucous leaflets; more numerous white flowers; and standard petals with a purple ring surrounding a bright yellow nectar patch.
- Full Text:
- Authors: Stirton, Charles H , Clark, Vincent Ralph , Barker, Nigel P , Muasya, A Muthama
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6543 , http://hdl.handle.net/10962/d1005999
- Description: A new species of Psoralea is described. Psoralea margaretiflora C.H. Stirton & V.R. Clark is endemic to the Sneeuberg Centre of Floristic Endemism, Eastern Cape, South Africa. This resprouter is characterised by its small greenish-white flowers with a small trifid purple nectar patch and translucent veins; 5(–7)-pinnate leaflets; multi-branching erect short seasonal flowering shoots; and tall habit of many stiff bare stems with the seasonal shoots massed at the apex. It is most similar to P. oligophylla Eckl. & Zeyh., a widespread species found in the Eastern Cape. The reseeder P. oligophylla differs in its lax virgate spreading habit with numerous long glaucous seasonal shoots; single stem, 1(–3)- glaucous leaflets; more numerous white flowers; and standard petals with a purple ring surrounding a bright yellow nectar patch.
- Full Text:
Publicising chemistry in a multicultural society through chemistry outreach
- Harrison, T G, Shallcross, D E, Norman, N C, Sewry, Joyce D, Davies-Coleman, Michael T
- Authors: Harrison, T G , Shallcross, D E , Norman, N C , Sewry, Joyce D , Davies-Coleman, Michael T
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6573 , http://hdl.handle.net/10962/d1004136
- Description: Given the emphasis in Higher Education on community engagement in South Africa and the importance of international collaboration, we discuss a joint approach to chemistry outreach in two countries on two continents with widely differing target school audiences. We describe the history of the partnership between the chemistry departments at Rhodes University and the University of Bristol and provide an outline of the chemistry content of their outreach initiatives, the modes of delivery, the advantages to both departments and their students for involvement in various levels of outreach, the challenges they still face and additional opportunities that such work facilitated. The lecture demonstration 'A Pollutant's Tale' was presented to thousands of learners all over the world, including learners at resource-deprived schools in South Africa. Challenges to extend outreach activities in South Africa include long travelling distances, as well as a lack of facilities (such as school halls and electricity) at schools. Outreach activities not only impacted on the target audience of young learners, they also impacted upon the postgraduate and other chemistry students taking part in these initiatives. This collaboration strengthened both institutions and their outreach work and may also lead to chemistry research collaborations between the academics involved.
- Full Text:
- Authors: Harrison, T G , Shallcross, D E , Norman, N C , Sewry, Joyce D , Davies-Coleman, Michael T
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6573 , http://hdl.handle.net/10962/d1004136
- Description: Given the emphasis in Higher Education on community engagement in South Africa and the importance of international collaboration, we discuss a joint approach to chemistry outreach in two countries on two continents with widely differing target school audiences. We describe the history of the partnership between the chemistry departments at Rhodes University and the University of Bristol and provide an outline of the chemistry content of their outreach initiatives, the modes of delivery, the advantages to both departments and their students for involvement in various levels of outreach, the challenges they still face and additional opportunities that such work facilitated. The lecture demonstration 'A Pollutant's Tale' was presented to thousands of learners all over the world, including learners at resource-deprived schools in South Africa. Challenges to extend outreach activities in South Africa include long travelling distances, as well as a lack of facilities (such as school halls and electricity) at schools. Outreach activities not only impacted on the target audience of young learners, they also impacted upon the postgraduate and other chemistry students taking part in these initiatives. This collaboration strengthened both institutions and their outreach work and may also lead to chemistry research collaborations between the academics involved.
- Full Text:
Putting old wine in new skins: the customary code of Lerotholi and justice administration in Lesotho
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/128780 , vital:36156 , https://doi.org/10.1017/CBO9780511844294.007
- Description: Although the interaction between the western colonizers and the African indigenous populations in the early eighteenth and nineteenth centuries produced responses that were mostly inimical to the development of African customary law, the thrust of the onslaught against its principles was somewhat diminished by political considerations. Undoubtedly, the significance that African customary law acquired during this period was a measure of the purpose that the colonial project found in it.
- Full Text: false
Putting old wine in new skins: the customary code of Lerotholi and justice administration in Lesotho
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/128780 , vital:36156 , https://doi.org/10.1017/CBO9780511844294.007
- Description: Although the interaction between the western colonizers and the African indigenous populations in the early eighteenth and nineteenth centuries produced responses that were mostly inimical to the development of African customary law, the thrust of the onslaught against its principles was somewhat diminished by political considerations. Undoubtedly, the significance that African customary law acquired during this period was a measure of the purpose that the colonial project found in it.
- Full Text: false
Quantifying crop damage by Grey crowned crane balearica regulorum regulorum and evaluating changes in crane distribution in the North Eastern Cape, South Africa
- Authors: Van Niekerk, Mark Harry
- Date: 2011
- Subjects: Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5749 , http://hdl.handle.net/10962/d1005436 , Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Description: Complaints of crop damage by cranes on planted maize in the North Eastern Cape, South Africa, have been increasing since the mid-1990‘s, and in some instances severe losses have been reported. Crop damage by the Grey Crowned Crane Balearica regulorum regulorum near the town of Maclear (31º04´S 28º22´E), has been quantified over two growing seasons, and assessed relative to losses caused by foraging Cape Crows Corvus capensis and other feeding damage assumed to be caused by insects. Twelve fields were selected based on previous patterns of crop depredation. Maize seed in seven of the fields was treated with the chemical ‗Gaucho‘ and five fields were planted with untreated maize. In order to determine the source of losses, twenty quadrats (4 m x 4 m) randomly distributed within each field were visited on average every second day, for a period of up to twenty eight days. Results indicate that seed treatments do act as a deterrent to feeding by both cranes and crows, however crane damage is generally insignificant compared to other sources of damage. My study also reviewed past sightings data of the Grey Crowned Crane in an effort to determine if the conversion of former grassland to plantations in this region may have increased foraging activity in maize fields. The data did not allow for clear-cut conclusions regarding changes in distribution or population trends. Conclusions provide direct input into the management of agricultural areas by enabling landowners to take steps to mitigate crop damage. These mitigation measures may either involve the application of seed treatments, or the planting of low risk crops in high risk areas. Future studies should consider the ppossible detrimental effects of chemical seed treatments on crane biology.
- Full Text:
- Authors: Van Niekerk, Mark Harry
- Date: 2011
- Subjects: Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5749 , http://hdl.handle.net/10962/d1005436 , Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Description: Complaints of crop damage by cranes on planted maize in the North Eastern Cape, South Africa, have been increasing since the mid-1990‘s, and in some instances severe losses have been reported. Crop damage by the Grey Crowned Crane Balearica regulorum regulorum near the town of Maclear (31º04´S 28º22´E), has been quantified over two growing seasons, and assessed relative to losses caused by foraging Cape Crows Corvus capensis and other feeding damage assumed to be caused by insects. Twelve fields were selected based on previous patterns of crop depredation. Maize seed in seven of the fields was treated with the chemical ‗Gaucho‘ and five fields were planted with untreated maize. In order to determine the source of losses, twenty quadrats (4 m x 4 m) randomly distributed within each field were visited on average every second day, for a period of up to twenty eight days. Results indicate that seed treatments do act as a deterrent to feeding by both cranes and crows, however crane damage is generally insignificant compared to other sources of damage. My study also reviewed past sightings data of the Grey Crowned Crane in an effort to determine if the conversion of former grassland to plantations in this region may have increased foraging activity in maize fields. The data did not allow for clear-cut conclusions regarding changes in distribution or population trends. Conclusions provide direct input into the management of agricultural areas by enabling landowners to take steps to mitigate crop damage. These mitigation measures may either involve the application of seed treatments, or the planting of low risk crops in high risk areas. Future studies should consider the ppossible detrimental effects of chemical seed treatments on crane biology.
- Full Text:
Queer transgressions : the choreographing of a male homosexual presence with reference to selected choreographers
- Authors: De Boer, Kyle Dylan
- Date: 2011
- Subjects: Queer theory , Gender identity in dance , Homosexuality in dance , Homosexuality and dance , Male homosexuality , Dance -- South Africa , Choreographers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2161 , http://hdl.handle.net/10962/d1009442
- Description: Queer Transgressions: The choreographing of a male homosexual presence with reference to selected choreographers explores queer identity and in particular representations of a male homosexual presence in dance. Within the methodological framework of dance studies and queer theory I explore the ―self fashioning‖ of my male homosexual presence in dance. This is achieved by critically deconstructing my choreographic process when making choreography. Therefore this thesis is informed by both academic research and my self-reflexive experience of choreography and dance performance. The deconstruction of my autobiography and choreographic process is discussed with reference to both international and South African queer choreographers. This means that by accounting for my own experiences and approaches toward representing a male homosexual presence in dance, I explore the history and engagements of other queer choreographers also creating such representations. I therefore examine the works of selected choreographers and chart the development of the representation of a male homosexual presence in dance. By exploring the choreographic process of other queer choreographers I identify choreographic tactics that queer choreographers are using when making work. From this point of departure I shift the focus away from international queer choreographers and provide insight into the choreographic processes of South African queer choreographers. By accounting for the works and choreographic processes of South African choreographers, I provide a context in which my choreographic explorations on the subject matter can take place. This choreographic exploration manifests itself through a self-reflexive/autobiographic account on the research and practice of my choreographic process. During my choreographic exploration I set the challenge to both engage with and explore further, established ―queering tactics. This is done with the intention to reveal and create representations of a male homosexual presence in dance.
- Full Text:
- Authors: De Boer, Kyle Dylan
- Date: 2011
- Subjects: Queer theory , Gender identity in dance , Homosexuality in dance , Homosexuality and dance , Male homosexuality , Dance -- South Africa , Choreographers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2161 , http://hdl.handle.net/10962/d1009442
- Description: Queer Transgressions: The choreographing of a male homosexual presence with reference to selected choreographers explores queer identity and in particular representations of a male homosexual presence in dance. Within the methodological framework of dance studies and queer theory I explore the ―self fashioning‖ of my male homosexual presence in dance. This is achieved by critically deconstructing my choreographic process when making choreography. Therefore this thesis is informed by both academic research and my self-reflexive experience of choreography and dance performance. The deconstruction of my autobiography and choreographic process is discussed with reference to both international and South African queer choreographers. This means that by accounting for my own experiences and approaches toward representing a male homosexual presence in dance, I explore the history and engagements of other queer choreographers also creating such representations. I therefore examine the works of selected choreographers and chart the development of the representation of a male homosexual presence in dance. By exploring the choreographic process of other queer choreographers I identify choreographic tactics that queer choreographers are using when making work. From this point of departure I shift the focus away from international queer choreographers and provide insight into the choreographic processes of South African queer choreographers. By accounting for the works and choreographic processes of South African choreographers, I provide a context in which my choreographic explorations on the subject matter can take place. This choreographic exploration manifests itself through a self-reflexive/autobiographic account on the research and practice of my choreographic process. During my choreographic exploration I set the challenge to both engage with and explore further, established ―queering tactics. This is done with the intention to reveal and create representations of a male homosexual presence in dance.
- Full Text:
Race, class and inequality: an exploration of the scholarship of Professor Bernard Magubane
- Authors: Tanyanyiwa, Precious
- Date: 2011
- Subjects: Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3324 , http://hdl.handle.net/10962/d1003112 , Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Description: This thesis begins with the assumption that the theory of academic dependency provides an adequate framework within which the relationship between social science communities in the North and South can be understood. Present problems of social scientists in the South have very often been attributed to this dependence and it has been concluded that academic dependence has resulted in an uncritical and imitative approach to ideas and concepts from the West (Alatas, 2000). This dependence has also resulted in the general regression among social scientists based in the South and in a marginalisation of their works within the social science community no matter how significant and original they may be. The problematic invisibility of the works of prominent South African scholars is a dimension of a wider crisis of academic dependence, if unchecked this current trend will also reinforce academic dependence. From the nature of the problems generated by academic dependence, it is obvious that there is a need for an intellectual emancipation movement. This movement may take different forms that may range from but are not limited to a commitment to endogeneity which involves among other things, knowledge production that takes South African local conditions seriously enough to be the basis for the development of distinct conceptual ideas and theories. This requires transcending the tendency to use ‘the local’ primarily as a tool for data collection and theoretical framing done from the global north. Secondly, there is a need to take the local, indigenous, ontological narratives seriously enough to serve as source codes for works of distinct epistemological value and exemplary ideas within the global project of knowledge production. Endogeneity in the context of African knowledge production should also involve an intellectual standpoint derived from a rootedness in the African conditions; a centring of African ontological discourses and experiences as the basis of intellectual work (Adesina, 2008: 135). In this study, it is suggested that the recommendations highlighted above can only succeed if scholars make an effort to actually engage with locally produced knowledge. There is therefore a need to make greater efforts to know each other’s work on Africa. This demand is not to appease individual egos but it is essential for progress in scientific work. African communities will benefit from drawing with greater catholicity from the well–spring of knowledge about Africa generated by Africans. In the South African context, transcending academic dependence in the new generation of young academics requires engagement with the work of our local scholars who have devoted their lives to knowledge production. This thesis explores the scholarship of Professor Bernard Magubane by engaging with his works on race, class and inequality by locating his works within the wider debates on race, class and inequality in South Africa. The specific contributions of Professor Magubane to the enterprise of knowledge production are identified and discussed in relation to his critique of Western social science in its application to Africa. The making of Professor Magubane’s life, his career, scholarship and biography details are analysed with the intention of showing their influence on Magubane as a Scholar. The examination of Professor Magubane’s intellectual and biographical accounts help to explain the details, contexts and implications of his theoretical paradigm shifts. This helps prove that Professor Magubane’s experiences and theoretical positions were socially and historically constituted. The research from which this thesis derives is part of an NRF-funded project, on Endogeneity and Modern Sociology in South Africa, under the direction of Professor Jimi Adesina.
- Full Text:
- Authors: Tanyanyiwa, Precious
- Date: 2011
- Subjects: Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3324 , http://hdl.handle.net/10962/d1003112 , Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Description: This thesis begins with the assumption that the theory of academic dependency provides an adequate framework within which the relationship between social science communities in the North and South can be understood. Present problems of social scientists in the South have very often been attributed to this dependence and it has been concluded that academic dependence has resulted in an uncritical and imitative approach to ideas and concepts from the West (Alatas, 2000). This dependence has also resulted in the general regression among social scientists based in the South and in a marginalisation of their works within the social science community no matter how significant and original they may be. The problematic invisibility of the works of prominent South African scholars is a dimension of a wider crisis of academic dependence, if unchecked this current trend will also reinforce academic dependence. From the nature of the problems generated by academic dependence, it is obvious that there is a need for an intellectual emancipation movement. This movement may take different forms that may range from but are not limited to a commitment to endogeneity which involves among other things, knowledge production that takes South African local conditions seriously enough to be the basis for the development of distinct conceptual ideas and theories. This requires transcending the tendency to use ‘the local’ primarily as a tool for data collection and theoretical framing done from the global north. Secondly, there is a need to take the local, indigenous, ontological narratives seriously enough to serve as source codes for works of distinct epistemological value and exemplary ideas within the global project of knowledge production. Endogeneity in the context of African knowledge production should also involve an intellectual standpoint derived from a rootedness in the African conditions; a centring of African ontological discourses and experiences as the basis of intellectual work (Adesina, 2008: 135). In this study, it is suggested that the recommendations highlighted above can only succeed if scholars make an effort to actually engage with locally produced knowledge. There is therefore a need to make greater efforts to know each other’s work on Africa. This demand is not to appease individual egos but it is essential for progress in scientific work. African communities will benefit from drawing with greater catholicity from the well–spring of knowledge about Africa generated by Africans. In the South African context, transcending academic dependence in the new generation of young academics requires engagement with the work of our local scholars who have devoted their lives to knowledge production. This thesis explores the scholarship of Professor Bernard Magubane by engaging with his works on race, class and inequality by locating his works within the wider debates on race, class and inequality in South Africa. The specific contributions of Professor Magubane to the enterprise of knowledge production are identified and discussed in relation to his critique of Western social science in its application to Africa. The making of Professor Magubane’s life, his career, scholarship and biography details are analysed with the intention of showing their influence on Magubane as a Scholar. The examination of Professor Magubane’s intellectual and biographical accounts help to explain the details, contexts and implications of his theoretical paradigm shifts. This helps prove that Professor Magubane’s experiences and theoretical positions were socially and historically constituted. The research from which this thesis derives is part of an NRF-funded project, on Endogeneity and Modern Sociology in South Africa, under the direction of Professor Jimi Adesina.
- Full Text:
Range extension of the Lufira Masked Weaver Ploceus ruweti, endemic to Katanga province, Democratic Republic of Congo
- Craig, Adrian J F K, Hasson, Michel, Jordaens, Kurt, Breman, Floris C, Louette, Michel
- Authors: Craig, Adrian J F K , Hasson, Michel , Jordaens, Kurt , Breman, Floris C , Louette, Michel
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449489 , vital:74825 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2010.523018
- Description: For many years the status of Ploceus ruweti Louette and Benson 1982, described from the unique male type specimen obtained in 1960 at Lake Lufira (an artificial impoundment on the Lufira River), remained obscure. However, in 2009 MH revisited the type locality, photographed the birds breeding there (including females and young birds), and rec-orded their song; nests and eggs were described for the first time, and a second male specimen was obtained from local fishermen (Louette and Hasson 2009; collection number RMCA A9-18-A-1). This species had been treated in the authoritative series The Birds of Africa as the Lake Lufira Weaver (Oschadleus 2004), and appears under this name in current checklists and fieldguides (eg Sinclair and Ryan 2003). Since the lake is now known as Lake Tshangalele and, based on our data from a recent field trip to the region, the bird is not restricted to the lake, an appropriate common name for P. ruweti is ‘Lufira Masked Weaver’as recommended by Gill and Wright (2006), and as used in a forthcoming volume of the other authoritative series Handbook of the Birds of the World (Craig 2010).
- Full Text:
- Authors: Craig, Adrian J F K , Hasson, Michel , Jordaens, Kurt , Breman, Floris C , Louette, Michel
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449489 , vital:74825 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2010.523018
- Description: For many years the status of Ploceus ruweti Louette and Benson 1982, described from the unique male type specimen obtained in 1960 at Lake Lufira (an artificial impoundment on the Lufira River), remained obscure. However, in 2009 MH revisited the type locality, photographed the birds breeding there (including females and young birds), and rec-orded their song; nests and eggs were described for the first time, and a second male specimen was obtained from local fishermen (Louette and Hasson 2009; collection number RMCA A9-18-A-1). This species had been treated in the authoritative series The Birds of Africa as the Lake Lufira Weaver (Oschadleus 2004), and appears under this name in current checklists and fieldguides (eg Sinclair and Ryan 2003). Since the lake is now known as Lake Tshangalele and, based on our data from a recent field trip to the region, the bird is not restricted to the lake, an appropriate common name for P. ruweti is ‘Lufira Masked Weaver’as recommended by Gill and Wright (2006), and as used in a forthcoming volume of the other authoritative series Handbook of the Birds of the World (Craig 2010).
- Full Text:
Raw phones: the domestication of mobile phones amongst young adults in Hooggenoeg, Grahamstown
- Authors: Schoon, Alette Jeanne
- Date: 2011
- Subjects: Cell phones -- Social aspects -- South Africa -- Grahamstown Communication -- Sex differences -- South Africa -- Grahamstown Social media -- South Africa -- Grahamstown Interpersonal communication -- Technological innovations -- Social aspects -- South Africa -- Grahamstown Communication and culture -- South Africa -- Grahamstown Online social networks -- Social aspects -- South Africa -- Grahamstown Mobile communication systems -- Social aspects -- South Africa -- Grahamstown Identity (Psychology) in youth Colored people (South Africa) -- Social life and customs -- South Africa -- Grahamstown Colored people (South Africa) -- Ethnic identity -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3482 , http://hdl.handle.net/10962/d1002937
- Description: This dissertation examines the meanings that young adults give to their mobile phones in the township of Hooggenoeg in Grahamstown in the Eastern Cape. The research was predominantly conducted through individual interviews with nine young adults as well as two small gender-based focus groups. Participant observation as well as a close reading of the popular mobile website Outoilet also contributed to the study. Drawing on Silverstone, Hirsch and Morley’s (1992) work into the meanings attributed to the mobile phone through the domestication processes of appropriation, objectification, incorporation and conversion, the study argues for the heterogeneous roles defined for mobile phones as they are integrated into different cultural contexts. The term ‘raw phones’ in the thesis title refers to a particular cultural understanding of respectability in mainly working-class ‘coloured’¹ communities in South Africa, as described by Salo (2007) and Ross (2010), in which race, class and gender converge in the construction of the respectable person’s opposite – a lascivious, almost certainly female, dependent, black and primitive ‘raw’ Other. The study argues that in Hooggenoeg, the mobile phone becomes part of semantic processes that define both respectability and ‘rawness’ , thus helping to reproduce social relations in this community along lines of race, class and gender. A major focus of the study is the instant messaging application MXit, and how it assists in the social production of space, by helping to constitute both private and dispersed network spaces of virtual communication, in a setting where social life is otherwise very public, and social networks outside of cyberspace are densely contiguous and localised. In contrast, gossip mobile website Outoilet seems to intensify this contiguous experience of space. My findings contest generalised claims, predominantly from the developed world, which assert that the mobile phone promotes mobility and an individualised society, and show that in particular contexts it may in fact promote immobility and create a collective sociability.
- Full Text:
- Authors: Schoon, Alette Jeanne
- Date: 2011
- Subjects: Cell phones -- Social aspects -- South Africa -- Grahamstown Communication -- Sex differences -- South Africa -- Grahamstown Social media -- South Africa -- Grahamstown Interpersonal communication -- Technological innovations -- Social aspects -- South Africa -- Grahamstown Communication and culture -- South Africa -- Grahamstown Online social networks -- Social aspects -- South Africa -- Grahamstown Mobile communication systems -- Social aspects -- South Africa -- Grahamstown Identity (Psychology) in youth Colored people (South Africa) -- Social life and customs -- South Africa -- Grahamstown Colored people (South Africa) -- Ethnic identity -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3482 , http://hdl.handle.net/10962/d1002937
- Description: This dissertation examines the meanings that young adults give to their mobile phones in the township of Hooggenoeg in Grahamstown in the Eastern Cape. The research was predominantly conducted through individual interviews with nine young adults as well as two small gender-based focus groups. Participant observation as well as a close reading of the popular mobile website Outoilet also contributed to the study. Drawing on Silverstone, Hirsch and Morley’s (1992) work into the meanings attributed to the mobile phone through the domestication processes of appropriation, objectification, incorporation and conversion, the study argues for the heterogeneous roles defined for mobile phones as they are integrated into different cultural contexts. The term ‘raw phones’ in the thesis title refers to a particular cultural understanding of respectability in mainly working-class ‘coloured’¹ communities in South Africa, as described by Salo (2007) and Ross (2010), in which race, class and gender converge in the construction of the respectable person’s opposite – a lascivious, almost certainly female, dependent, black and primitive ‘raw’ Other. The study argues that in Hooggenoeg, the mobile phone becomes part of semantic processes that define both respectability and ‘rawness’ , thus helping to reproduce social relations in this community along lines of race, class and gender. A major focus of the study is the instant messaging application MXit, and how it assists in the social production of space, by helping to constitute both private and dispersed network spaces of virtual communication, in a setting where social life is otherwise very public, and social networks outside of cyberspace are densely contiguous and localised. In contrast, gossip mobile website Outoilet seems to intensify this contiguous experience of space. My findings contest generalised claims, predominantly from the developed world, which assert that the mobile phone promotes mobility and an individualised society, and show that in particular contexts it may in fact promote immobility and create a collective sociability.
- Full Text:
Redox activity of CdTe quantum dots linked to nickel tetraaminophthalocyanine
- Khene, Samson, Nyokong, Tebello
- Authors: Khene, Samson , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246457 , vital:51478 , xlink:href="https://doi.org/10.1016/j.microc.2011.06.024"
- Description: Cadmium tellurite quantum dots (CdTe-QDs) are linked to nickel tetraamino phthalocyanine (CdTe-QDs-NiTAPc) through an amide bond. Differential pulse voltammetry shows that that NiTAPc stabilizes the QDs against oxidative disintegration into metallic products on oxidation. Electrocatalytic oxidation of 2, 4-dichlorophenol (DCP) and pentachlorophenol (PCP) on CdTe-QDs and CdTe-QDs-NiTAPc adsorbed or electrodeposited onto a gold electrode were studied. Adsorbed CdTe-QDs-NiTAPc shows the lowest potential for DCP and PCP oxidation and it is also more stable to fouling by PCP and its oxidation products compared to adsorbed CdTe-QDs without NiTAPc. Electrodeposited CdTe-QDs or CdTe-QDs-NiTAPc show the best activity in terms of enhanced currents towards the oxidation of the chlorophenols.
- Full Text:
- Authors: Khene, Samson , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246457 , vital:51478 , xlink:href="https://doi.org/10.1016/j.microc.2011.06.024"
- Description: Cadmium tellurite quantum dots (CdTe-QDs) are linked to nickel tetraamino phthalocyanine (CdTe-QDs-NiTAPc) through an amide bond. Differential pulse voltammetry shows that that NiTAPc stabilizes the QDs against oxidative disintegration into metallic products on oxidation. Electrocatalytic oxidation of 2, 4-dichlorophenol (DCP) and pentachlorophenol (PCP) on CdTe-QDs and CdTe-QDs-NiTAPc adsorbed or electrodeposited onto a gold electrode were studied. Adsorbed CdTe-QDs-NiTAPc shows the lowest potential for DCP and PCP oxidation and it is also more stable to fouling by PCP and its oxidation products compared to adsorbed CdTe-QDs without NiTAPc. Electrodeposited CdTe-QDs or CdTe-QDs-NiTAPc show the best activity in terms of enhanced currents towards the oxidation of the chlorophenols.
- Full Text:
Regional application of the Pitman monthly rainfall-runoff model in Southern Africa incorporating uncertainty
- Authors: Kapangaziwiri, Evison
- Date: 2011
- Subjects: Water supply -- Africa, Southern Water supply -- Measurement -- Africa, Southern Hydrology -- Mathematical models -- Africa, Southern Hydrologic models Rain and rainfall -- Mathematical models -- Africa, Southern Runoff -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6037 , http://hdl.handle.net/10962/d1006178
- Description: Climate change and a growing demand for freshwater resources due to population increases and socio-economic changes will make water a limiting factor (in terms of both quantity and quality) in development. The need for reliable quantitative estimates of water availability cannot be over-emphasised. However, there is frequently a paucity of the data required for this quantification as many basins, especially in the developing world, are inadequately equipped with monitoring networks. Existing networks are also shrinking due mainly to shortages in human and financial resources. Over the past few decades mathematical models have been used to bridge the data gap by generating datasets for use in management and policy making. In southern Africa, the Pitman monthly rainfall-runoff model has enjoyed relatively popular use as a water resources estimation tool. However, it is acknowledged that models are abstractions of reality and the data used to drive them is imperfect, making the model outputs uncertain. While there is acknowledgement of the limitations of modelled data in the southern African region among water practitioners, there has been little effort to explicitly quantify and account for this uncertainty in water resources estimation tools and explore how it affects the decision making process. Uncertainty manifests itself in three major areas of the modelling chain; the input data used to force the model, the parameter estimation process and the model structural errors. A previous study concluded that the parameter estimation process for the Pitman model contributed more to the global uncertainty of the model than other sources. While the literature abounds with uncertainty estimation techniques, many of these are dependent on observations and are therefore unlikely to be easily applicable to the southern African region where there is an acute shortage of such data. This study focuses on two aspects of making hydrologic predictions in ungauged basins. Firstly, the study advocates the development of an a priori parameter estimation process for the Pitman model and secondly, uses indices of hydrological functional behaviour to condition and reduce predictive uncertainty in both gauged and ungauged basins. In this approach all the basins are treated as ungauged, while the historical records in the gauged basins are used to develop regional indices of expected hydrological behaviour and assess the applicability of these methods. Incorporating uncertainty into the hydrologic estimation tools used in southern Africa entails rethinking the way the uncertain results can be used in further analysis and how they will be interpreted by stakeholders. An uncertainty framework is proposed. The framework is made up of a number of components related to the estimation of the prior distribution of the parameters, used to generate output ensembles which are then assessed and constrained using regionalised indices of basin behavioural responses. This is premised on such indices being based on the best available knowledge covering different regions. This framework is flexible enough to be used with any model structure to ensure consistent and comparable results. While the aim is to eventually apply the uncertainty framework in the southern African region, this study reports on the preliminary work on the development and testing of the framework components based on South African basins. This is necessitated by the variations in the availability and quality of the data across the region. Uncertainty in the parameter estimation process was incorporated by assuming uncertainty in the physical and hydro-meteorological data used to directly quantify the parameter. This uncertainty was represented by the range of variability of these basin characteristics and probability distribution functions were developed to account for this uncertainty and propagate it through the estimation process to generate posterior distributions for the parameters. The results show that the framework has a great deal of potential but can still be improved. In general, the estimated uncertain parameters managed to produce hydrologically realistic model outputs capturing the expected regimes across the different hydro-climatic and geo-physical gradients examined. The regional relationships for the three indices developed and tested in this study were in general agreement with existing knowledge and managed to successfully provide a multi-criteria conditioning of the model output ensembles. The feedback loop included in the framework enabled a systematic re-examination of the estimation procedures for both the parameters and the indices when inconsistencies in the results were identified. This improved results. However, there is need to carefully examine the issues and problems that may arise within other basins outside South Africa and develop guidelines for the use of the framework. , iText 1.4.6 (by lowagie.com)
- Full Text:
- Authors: Kapangaziwiri, Evison
- Date: 2011
- Subjects: Water supply -- Africa, Southern Water supply -- Measurement -- Africa, Southern Hydrology -- Mathematical models -- Africa, Southern Hydrologic models Rain and rainfall -- Mathematical models -- Africa, Southern Runoff -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6037 , http://hdl.handle.net/10962/d1006178
- Description: Climate change and a growing demand for freshwater resources due to population increases and socio-economic changes will make water a limiting factor (in terms of both quantity and quality) in development. The need for reliable quantitative estimates of water availability cannot be over-emphasised. However, there is frequently a paucity of the data required for this quantification as many basins, especially in the developing world, are inadequately equipped with monitoring networks. Existing networks are also shrinking due mainly to shortages in human and financial resources. Over the past few decades mathematical models have been used to bridge the data gap by generating datasets for use in management and policy making. In southern Africa, the Pitman monthly rainfall-runoff model has enjoyed relatively popular use as a water resources estimation tool. However, it is acknowledged that models are abstractions of reality and the data used to drive them is imperfect, making the model outputs uncertain. While there is acknowledgement of the limitations of modelled data in the southern African region among water practitioners, there has been little effort to explicitly quantify and account for this uncertainty in water resources estimation tools and explore how it affects the decision making process. Uncertainty manifests itself in three major areas of the modelling chain; the input data used to force the model, the parameter estimation process and the model structural errors. A previous study concluded that the parameter estimation process for the Pitman model contributed more to the global uncertainty of the model than other sources. While the literature abounds with uncertainty estimation techniques, many of these are dependent on observations and are therefore unlikely to be easily applicable to the southern African region where there is an acute shortage of such data. This study focuses on two aspects of making hydrologic predictions in ungauged basins. Firstly, the study advocates the development of an a priori parameter estimation process for the Pitman model and secondly, uses indices of hydrological functional behaviour to condition and reduce predictive uncertainty in both gauged and ungauged basins. In this approach all the basins are treated as ungauged, while the historical records in the gauged basins are used to develop regional indices of expected hydrological behaviour and assess the applicability of these methods. Incorporating uncertainty into the hydrologic estimation tools used in southern Africa entails rethinking the way the uncertain results can be used in further analysis and how they will be interpreted by stakeholders. An uncertainty framework is proposed. The framework is made up of a number of components related to the estimation of the prior distribution of the parameters, used to generate output ensembles which are then assessed and constrained using regionalised indices of basin behavioural responses. This is premised on such indices being based on the best available knowledge covering different regions. This framework is flexible enough to be used with any model structure to ensure consistent and comparable results. While the aim is to eventually apply the uncertainty framework in the southern African region, this study reports on the preliminary work on the development and testing of the framework components based on South African basins. This is necessitated by the variations in the availability and quality of the data across the region. Uncertainty in the parameter estimation process was incorporated by assuming uncertainty in the physical and hydro-meteorological data used to directly quantify the parameter. This uncertainty was represented by the range of variability of these basin characteristics and probability distribution functions were developed to account for this uncertainty and propagate it through the estimation process to generate posterior distributions for the parameters. The results show that the framework has a great deal of potential but can still be improved. In general, the estimated uncertain parameters managed to produce hydrologically realistic model outputs capturing the expected regimes across the different hydro-climatic and geo-physical gradients examined. The regional relationships for the three indices developed and tested in this study were in general agreement with existing knowledge and managed to successfully provide a multi-criteria conditioning of the model output ensembles. The feedback loop included in the framework enabled a systematic re-examination of the estimation procedures for both the parameters and the indices when inconsistencies in the results were identified. This improved results. However, there is need to carefully examine the issues and problems that may arise within other basins outside South Africa and develop guidelines for the use of the framework. , iText 1.4.6 (by lowagie.com)
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Regulation and risk assessment for importations and releases of biological control agents against invasive alien plants in South Africa
- Klein, Hildegard, Hill, Martin P, Zachariades, Costas, Zimmermann, Helmuth G
- Authors: Klein, Hildegard , Hill, Martin P , Zachariades, Costas , Zimmermann, Helmuth G
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451481 , vital:75052 , https://hdl.handle.net/10520/EJC32898
- Description: The importation and release of biological control agents against invasive alien plants in South Africa are subject to regulation by the Department of Agriculture, Forestry and Fisheries (DAFF), under its Agricultural Pests Act, and by the Department of Environmental Affairs (DEA), initially under its Environment Conservation Act, subsequently under the National Environmental Management Act and eventually, as soon as the relevant regulations have been developed, under the National Environmental Management: Biodiversity Act. Peer review, both within South Africa, and with colleagues in other countries, has helped to ensure the integrity of the science and practice of weed biological control in South Africa. This paper traces the development of the regulatory system from the first weed biological control project in 1913, through a dispensation when importations and releases were authorized by DAFF only to a dual regulatory system involving two government departments. Inappropriate legislation, lack of knowledge about biological control amongst the relevant authorities and the costs of employing compulsory private consultants are some of the reasons for significant delays that have become a feature in the authorization of biological control agent releases. These delays have set back several control programmes. Holding agents in quarantine while awaiting decisions ties up expensive space and staff time and increases the risk of losing colonies through accidents or decreased genetic vigour. It seems likely that changes in legislation within DEA will streamline the regulatory process in the near future.
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- Authors: Klein, Hildegard , Hill, Martin P , Zachariades, Costas , Zimmermann, Helmuth G
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451481 , vital:75052 , https://hdl.handle.net/10520/EJC32898
- Description: The importation and release of biological control agents against invasive alien plants in South Africa are subject to regulation by the Department of Agriculture, Forestry and Fisheries (DAFF), under its Agricultural Pests Act, and by the Department of Environmental Affairs (DEA), initially under its Environment Conservation Act, subsequently under the National Environmental Management Act and eventually, as soon as the relevant regulations have been developed, under the National Environmental Management: Biodiversity Act. Peer review, both within South Africa, and with colleagues in other countries, has helped to ensure the integrity of the science and practice of weed biological control in South Africa. This paper traces the development of the regulatory system from the first weed biological control project in 1913, through a dispensation when importations and releases were authorized by DAFF only to a dual regulatory system involving two government departments. Inappropriate legislation, lack of knowledge about biological control amongst the relevant authorities and the costs of employing compulsory private consultants are some of the reasons for significant delays that have become a feature in the authorization of biological control agent releases. These delays have set back several control programmes. Holding agents in quarantine while awaiting decisions ties up expensive space and staff time and increases the risk of losing colonies through accidents or decreased genetic vigour. It seems likely that changes in legislation within DEA will streamline the regulatory process in the near future.
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Relational processes enabling the balancing of academic work and motherhood: a grounded theory study with academic women at a South African university
- Authors: Poulos, Tessa
- Date: 2011
- Subjects: Working mothers -- South Africa -- Grahamstown Women in education -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Rhodes University -- Employees Motherhood -- South Africa -- Grahamstown Sex role in the work environment -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3038 , http://hdl.handle.net/10962/d1002547
- Description: Through the use of contextual data, this research study aims to explicate a theory about the experiences of academic women, who are also mothers, employed at a South African University. The research is interpretive in nature as it explores the women's accounts of the conflicts they face in striving to satisfy the demands of both their scholarly work and family responsibilities within multiple intersecting factors related to their personal/familial circumstances, and the strategic processes they engage in to manage the balance between these competing roles. The study followed a constructivist grounded theory design in an attempt to test the hypothesis (emerging from a prior pilot study) that the most significant enabling factors at work in the lives of these women comprise various relational support processes. The findings indicate that balancing academic work and mothering is a delicate activity that is sensitive to a number of facilitating as well as hindering factors. The participants revealed that they experience work-family role-conflict as a result of competing desires to dedicate themselves fully to both of these roles. The relational factors most prominently cited as being critical to enabling a work-family balance include the presence of a supportive partner, a support structure in the home in the form of an employed domestic helper, and the support derived from a 'shared experience' with other working mothers. Non-relational factors emanating from the unique quality of life afforded to mothers by employment within the particular case institution also emerged as being significantly enabling of a work-family balance for this group of academic mothers.
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- Authors: Poulos, Tessa
- Date: 2011
- Subjects: Working mothers -- South Africa -- Grahamstown Women in education -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Rhodes University -- Employees Motherhood -- South Africa -- Grahamstown Sex role in the work environment -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3038 , http://hdl.handle.net/10962/d1002547
- Description: Through the use of contextual data, this research study aims to explicate a theory about the experiences of academic women, who are also mothers, employed at a South African University. The research is interpretive in nature as it explores the women's accounts of the conflicts they face in striving to satisfy the demands of both their scholarly work and family responsibilities within multiple intersecting factors related to their personal/familial circumstances, and the strategic processes they engage in to manage the balance between these competing roles. The study followed a constructivist grounded theory design in an attempt to test the hypothesis (emerging from a prior pilot study) that the most significant enabling factors at work in the lives of these women comprise various relational support processes. The findings indicate that balancing academic work and mothering is a delicate activity that is sensitive to a number of facilitating as well as hindering factors. The participants revealed that they experience work-family role-conflict as a result of competing desires to dedicate themselves fully to both of these roles. The relational factors most prominently cited as being critical to enabling a work-family balance include the presence of a supportive partner, a support structure in the home in the form of an employed domestic helper, and the support derived from a 'shared experience' with other working mothers. Non-relational factors emanating from the unique quality of life afforded to mothers by employment within the particular case institution also emerged as being significantly enabling of a work-family balance for this group of academic mothers.
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Remains to be said: The "um" in art and other disfluencies
- Authors: de Jager, Maureen
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147369 , vital:38630 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC45815
- Description: Taking as my starting point an artwork of "fillers" - a 2010 sound piece by Fine Art student Romie Sciscio foregrounding the disfluent speech of various visiting academics to the Department of Fine Art, Rhodes University - I propose that speech disfluencies such as "um", "kind of" and "I suppose" should not simply be derided as white noise or verbal graffiti. Rather, filled pauses - understood both literally and metaphorically - may be seen to function critically, precisely because they are located neither inside nor outside the "message" of speech. They hover between presence and absence, seemingly content-less and yet dimly portentous: they do and do not matter to meaning. As such, they require (or provoke and demand) a different kind of listening - the acoustic equivalent of reading between the lines.
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- Authors: de Jager, Maureen
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147369 , vital:38630 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC45815
- Description: Taking as my starting point an artwork of "fillers" - a 2010 sound piece by Fine Art student Romie Sciscio foregrounding the disfluent speech of various visiting academics to the Department of Fine Art, Rhodes University - I propose that speech disfluencies such as "um", "kind of" and "I suppose" should not simply be derided as white noise or verbal graffiti. Rather, filled pauses - understood both literally and metaphorically - may be seen to function critically, precisely because they are located neither inside nor outside the "message" of speech. They hover between presence and absence, seemingly content-less and yet dimly portentous: they do and do not matter to meaning. As such, they require (or provoke and demand) a different kind of listening - the acoustic equivalent of reading between the lines.
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Report on the Mesozoic volcanic and intrusive rocks on the Namibe Basin, Southwest Angola:
- Authors: Marsh, Julian S
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144846 , vital:38384
- Description: The Bero Volcanic Complex comprises a diverse group of quartz latite and tholeiitic basalt lavas, pyroclastic and volcaniclastic deposits, aeolian sandstones as well as intrusive tholeiitic mafic dykes and gabbros. Only the silicic members of this suite have received prior attention being referred to as “granitic porphyries” by Carvalho (1961) who regarded them as being Precambrian in age. Alberti et al.(1992) informally referred to these silicic rocks as the ‘Giraul Volcanics’ and correlated them with the early Cretaceous Paraná-Etendeka Igneous Province of Brazil and Namibia.
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- Authors: Marsh, Julian S
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144846 , vital:38384
- Description: The Bero Volcanic Complex comprises a diverse group of quartz latite and tholeiitic basalt lavas, pyroclastic and volcaniclastic deposits, aeolian sandstones as well as intrusive tholeiitic mafic dykes and gabbros. Only the silicic members of this suite have received prior attention being referred to as “granitic porphyries” by Carvalho (1961) who regarded them as being Precambrian in age. Alberti et al.(1992) informally referred to these silicic rocks as the ‘Giraul Volcanics’ and correlated them with the early Cretaceous Paraná-Etendeka Igneous Province of Brazil and Namibia.
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