'The Area of a Triangle is 1800C’: an analysis of Learners' Idiosyncratic Geometry Responses through the Lenses of Vygotsky's Theory of Concept Formation
- Mhlolo, Michael K, Schäfer, Marc
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141127 , vital:37946 , DOI: 10.1080/10288457.2013.826973
- Description: In this paper, we focus specifically on Vygotsky's theory of concept formation to gain initial insights into seemingly garbled and incoherent connections we observed in learners' responses to a geometry task. While acknowledging research that is supportive of the van Hiele model as being useful when analysing concept formation in geometry, in this paper we use empirical evidence to argue that today's geometry requires learners to reason with many tools which the van Hiele model does not seem to accommodate. Working with 470 written responses of 12–14-year-old learners to a geometry task, we then explored the potential of Vygotsky's theory of concept formation as an alternative framework. We conclude by discussing the paper's contribution both to theory and to classroom practice.
- Full Text:
- Date Issued: 2013
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141127 , vital:37946 , DOI: 10.1080/10288457.2013.826973
- Description: In this paper, we focus specifically on Vygotsky's theory of concept formation to gain initial insights into seemingly garbled and incoherent connections we observed in learners' responses to a geometry task. While acknowledging research that is supportive of the van Hiele model as being useful when analysing concept formation in geometry, in this paper we use empirical evidence to argue that today's geometry requires learners to reason with many tools which the van Hiele model does not seem to accommodate. Working with 470 written responses of 12–14-year-old learners to a geometry task, we then explored the potential of Vygotsky's theory of concept formation as an alternative framework. We conclude by discussing the paper's contribution both to theory and to classroom practice.
- Full Text:
- Date Issued: 2013
13C pulse-chase labeling comparative assessment of the active methanogenic archaeal community composition in the transgenic and nontransgenic parental rice rhizospheres
- Zhu, Weijing, Lu, Haohao, Hill, Jaclyn M, Wang, Hailong, Wu, Weixiang
- Authors: Zhu, Weijing , Lu, Haohao , Hill, Jaclyn M , Wang, Hailong , Wu, Weixiang
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/122993 , vital:35389 , https://doi.org/10.1111/1574-6941.12261
- Description: Rhabdosargus holubi (Steindachner, 1881) is a small (maximum size = 450 mm total length; Heemstra and Heemstra 2004) sparid that is distributed along the south-east coast of Africa from St Helena Bay, South Africa, to Maputo, Mozambique (Götz and Cowley 2013). Spawning occurs in the nearshore marine environment primarily during winter, specifically May–August in KwaZulu-Natal (KZN) (Wallace 1975) and July–February in the South-Eastern Cape (Whitfield 1998). Individuals reach 50% sexual maturity at approximately 150 mm standard length (SL) in the Eastern Cape (Whitfield 1998). The early life stages are transported by the south-westward-flowing Agulhas Current, and recruit as post-flexion larvae and early juveniles into estuaries during late winter and early summer (Blaber 1974). The warm temperatures and high nutrient levels in estuaries favour fast growth (Blaber 1973a), and fish spend their first year of life in these environments, migrating back out to sea after reaching approximately 120 mm SL. Some individuals remain trapped in closed estuaries, where they may reach sizes greater than 200 mm SL (James et al. 2007a). Rhabdosargus holubi is the dominant estuarine-dependent marine teleost species recorded in permanently open and temporarily open/closed estuaries in the warm-temperate region, which spans the south, south-east and east coast of South Africa (Harrison 2005). The species is also an important component of the linefishery in many SouthAfrican estuaries (10–15.6% by number) (Pradervand and Baird 2002), particularly in Eastern Cape estuaries (Cowley et al. 2003). These figures underestimate the presence of R. holubi, as most individuals making use of estuaries are young, feeding predominately on filamentous macroalgae and diatom flora, and are generally too small to be caught with hook and line (De Wet and Marais 1990). James et al. (2007b) showed that R. holubi made up 34–92% of the annual seine-net catch in the East Kleinemonde Estuary. Rhabdosargus holubi is also important in the KZN shorebased linefishery, representing 4.6% of the total landed catch (Dunlop and Mann 2012)More and more investigations indicate that genetic modification has no significant or persistent effects on microbial community composition in the rice rhizosphere. Very few studies, however, have focused on its impact on functional microorganisms. This study completed a 13C-CO2 pulse-chase labeling experiment comparing the potential effects of cry1Ab gene transformation on 13C tissue distribution and rhizosphere methanogenic archaeal community composition with its parental rice variety (Ck) and a distant parental rice variety (Dp). Results showed that 13C partitioning in aboveground biomass (mainly in stems) and roots of Dp was significantly lower than that of Ck. However, there were no significant differences in 13C partitioning between the Bt transgenic rice line (Bt) and Ck. RNA-stable isotope probing combined with clone library analyses inferred that the group Methanosaetaceae was the predominant methanogenic Archaea in all three rice rhizospheres. The active methanogenic archaeal community in the Bt rhizosphere was dominated by Methanosarcinaceae, Methanosaetaceae, and Methanomicrobiaceae, while there were only two main methanogenic clusters (Methanosaetaceae and Methanomicrobiaceae) in the Ck and Dp rhizospheres. These results indicate that the insertion of cry1Ab gene into the rice genome has the potential to result in the modification of methanogenic community composition in its rhizosphere.
- Full Text:
- Date Issued: 2013
- Authors: Zhu, Weijing , Lu, Haohao , Hill, Jaclyn M , Wang, Hailong , Wu, Weixiang
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/122993 , vital:35389 , https://doi.org/10.1111/1574-6941.12261
- Description: Rhabdosargus holubi (Steindachner, 1881) is a small (maximum size = 450 mm total length; Heemstra and Heemstra 2004) sparid that is distributed along the south-east coast of Africa from St Helena Bay, South Africa, to Maputo, Mozambique (Götz and Cowley 2013). Spawning occurs in the nearshore marine environment primarily during winter, specifically May–August in KwaZulu-Natal (KZN) (Wallace 1975) and July–February in the South-Eastern Cape (Whitfield 1998). Individuals reach 50% sexual maturity at approximately 150 mm standard length (SL) in the Eastern Cape (Whitfield 1998). The early life stages are transported by the south-westward-flowing Agulhas Current, and recruit as post-flexion larvae and early juveniles into estuaries during late winter and early summer (Blaber 1974). The warm temperatures and high nutrient levels in estuaries favour fast growth (Blaber 1973a), and fish spend their first year of life in these environments, migrating back out to sea after reaching approximately 120 mm SL. Some individuals remain trapped in closed estuaries, where they may reach sizes greater than 200 mm SL (James et al. 2007a). Rhabdosargus holubi is the dominant estuarine-dependent marine teleost species recorded in permanently open and temporarily open/closed estuaries in the warm-temperate region, which spans the south, south-east and east coast of South Africa (Harrison 2005). The species is also an important component of the linefishery in many SouthAfrican estuaries (10–15.6% by number) (Pradervand and Baird 2002), particularly in Eastern Cape estuaries (Cowley et al. 2003). These figures underestimate the presence of R. holubi, as most individuals making use of estuaries are young, feeding predominately on filamentous macroalgae and diatom flora, and are generally too small to be caught with hook and line (De Wet and Marais 1990). James et al. (2007b) showed that R. holubi made up 34–92% of the annual seine-net catch in the East Kleinemonde Estuary. Rhabdosargus holubi is also important in the KZN shorebased linefishery, representing 4.6% of the total landed catch (Dunlop and Mann 2012)More and more investigations indicate that genetic modification has no significant or persistent effects on microbial community composition in the rice rhizosphere. Very few studies, however, have focused on its impact on functional microorganisms. This study completed a 13C-CO2 pulse-chase labeling experiment comparing the potential effects of cry1Ab gene transformation on 13C tissue distribution and rhizosphere methanogenic archaeal community composition with its parental rice variety (Ck) and a distant parental rice variety (Dp). Results showed that 13C partitioning in aboveground biomass (mainly in stems) and roots of Dp was significantly lower than that of Ck. However, there were no significant differences in 13C partitioning between the Bt transgenic rice line (Bt) and Ck. RNA-stable isotope probing combined with clone library analyses inferred that the group Methanosaetaceae was the predominant methanogenic Archaea in all three rice rhizospheres. The active methanogenic archaeal community in the Bt rhizosphere was dominated by Methanosarcinaceae, Methanosaetaceae, and Methanomicrobiaceae, while there were only two main methanogenic clusters (Methanosaetaceae and Methanomicrobiaceae) in the Ck and Dp rhizospheres. These results indicate that the insertion of cry1Ab gene into the rice genome has the potential to result in the modification of methanogenic community composition in its rhizosphere.
- Full Text:
- Date Issued: 2013
A baseline study of youth identity, the media and the public sphere in South Africa:
- Malila, Vanessa, Duncan, Jane, Costera Meijer, Irene, Drok, Nico, Garman, Anthea, Strelitz, Larry N, Steenveld, Lynette N, Bosch, Tanja, Ndlovu, Musa
- Authors: Malila, Vanessa , Duncan, Jane , Costera Meijer, Irene , Drok, Nico , Garman, Anthea , Strelitz, Larry N , Steenveld, Lynette N , Bosch, Tanja , Ndlovu, Musa
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159780 , vital:40343 , https://research.vu.nl/ws/portalfiles/portal/3635364/Baseline+study+single+column+(1).pdf
- Description: The project on youth identity, the media and the public sphere in South Africa was led by Prof Jane Duncan, Highway Africa Chair of Media and Information Society, at Rhodes University in South Africa. The research project was funded by the South Africa Netherlands Research Programme on Alternatives in Development (SANPAD), and partnered in the Netherlands with Prof Irene Costera Meijer (of VU University of Amsterdam) and Prof Nico Drok (of Windesheim University).
- Full Text:
- Date Issued: 2013
- Authors: Malila, Vanessa , Duncan, Jane , Costera Meijer, Irene , Drok, Nico , Garman, Anthea , Strelitz, Larry N , Steenveld, Lynette N , Bosch, Tanja , Ndlovu, Musa
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159780 , vital:40343 , https://research.vu.nl/ws/portalfiles/portal/3635364/Baseline+study+single+column+(1).pdf
- Description: The project on youth identity, the media and the public sphere in South Africa was led by Prof Jane Duncan, Highway Africa Chair of Media and Information Society, at Rhodes University in South Africa. The research project was funded by the South Africa Netherlands Research Programme on Alternatives in Development (SANPAD), and partnered in the Netherlands with Prof Irene Costera Meijer (of VU University of Amsterdam) and Prof Nico Drok (of Windesheim University).
- Full Text:
- Date Issued: 2013
A capability approach: Its potential for transformative education research focusing on education for sustainable development and gender issues in science teacher education
- Authors: Chikunda, Charles
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387120 , vital:68208 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122266"
- Description: In this article, I use the capability approach to explore the role that the science, mathematics and technical subjects (SMTs) teacher education curriculum can play as a ‘gender conversion factor’. This comes amidst evidence that a major hindrance to the participation of girls in these disciplines is a lack of gender responsiveness in the pedagogy applied in schools. Seven teacher educators, who were purposively sampled at a Technical Teachers’ College in Zimbabwe, were the research participants. I adopted a case study design in which I used in-depth interviews, focus-group discussions and document analysis to generate data. Data was analysed deductively using predetermined themes based on an analytical tool anchored on Sen’s two, but quite distinct, aspects of freedom, that is, the opportunity aspect and the process aspect of freedom. The findings reveal that there is a limited awareness of gender issues among teacher educators, and that these issues are not being transformed into curriculum practice. All in all, it is evident that curriculum practices of SMTs teacher educators are riddled with gender blindness and so trainee teachers graduate from college without the necessary agency to deal with personal, social and environmental conversion factors that can play a role in girls converting the curriculum into functionings (beings and doings) and wider freedoms and valued beings and doings (capabilities).
- Full Text:
- Date Issued: 2013
- Authors: Chikunda, Charles
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387120 , vital:68208 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122266"
- Description: In this article, I use the capability approach to explore the role that the science, mathematics and technical subjects (SMTs) teacher education curriculum can play as a ‘gender conversion factor’. This comes amidst evidence that a major hindrance to the participation of girls in these disciplines is a lack of gender responsiveness in the pedagogy applied in schools. Seven teacher educators, who were purposively sampled at a Technical Teachers’ College in Zimbabwe, were the research participants. I adopted a case study design in which I used in-depth interviews, focus-group discussions and document analysis to generate data. Data was analysed deductively using predetermined themes based on an analytical tool anchored on Sen’s two, but quite distinct, aspects of freedom, that is, the opportunity aspect and the process aspect of freedom. The findings reveal that there is a limited awareness of gender issues among teacher educators, and that these issues are not being transformed into curriculum practice. All in all, it is evident that curriculum practices of SMTs teacher educators are riddled with gender blindness and so trainee teachers graduate from college without the necessary agency to deal with personal, social and environmental conversion factors that can play a role in girls converting the curriculum into functionings (beings and doings) and wider freedoms and valued beings and doings (capabilities).
- Full Text:
- Date Issued: 2013
A cooperative benefits framework in South Africa's land redistribution process: the case of sugarcane farmland transfers
- Mbatha, Cyril N, Antrobus, Geoffrey G
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142922 , vital:38176 , DOI: 10.1080/03031853.2012.741207
- Description: A good indicator of successful land redistribution cases has to be the continuation of viable productivity rates in their post-transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately, negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to illustrate and argue that cooperation among key stakeholders, which could be enforced through long-term contracts between land buyers, sellers and new owners, may lead to maintenance and higher productivity levels and other benefits within the country's land redistribution process.
- Full Text:
- Date Issued: 2013
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142922 , vital:38176 , DOI: 10.1080/03031853.2012.741207
- Description: A good indicator of successful land redistribution cases has to be the continuation of viable productivity rates in their post-transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately, negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to illustrate and argue that cooperation among key stakeholders, which could be enforced through long-term contracts between land buyers, sellers and new owners, may lead to maintenance and higher productivity levels and other benefits within the country's land redistribution process.
- Full Text:
- Date Issued: 2013
A Crown on the Move: stylistic integration of the Luba-Lunda complex in Lunda-Kazembe performance
- Authors: Simbao, Ruth K
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147524 , vital:38646 , https://doi.org/10.1162/afar.2006.39.3.26
- Description: Carried on a scarlet and zebra-hide litter above the heads of a throbbing crowd, Mwata Kazembe XIX gloriously stretches out his arms as if to embrace a world that is his own (Fig. 1). As he parts the sea of well-wishers, splashes of red burst into view and the talking drum beats out its decree. Basking in a charged clamor where the senses blur in clouds of dust, Mwata gracefully sways from side to side, jangling the beads and cowries on the back of his akatasa crown. It is on this day that the Lunda-Kazembe Crown moves.
- Full Text:
- Date Issued: 2013
- Authors: Simbao, Ruth K
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147524 , vital:38646 , https://doi.org/10.1162/afar.2006.39.3.26
- Description: Carried on a scarlet and zebra-hide litter above the heads of a throbbing crowd, Mwata Kazembe XIX gloriously stretches out his arms as if to embrace a world that is his own (Fig. 1). As he parts the sea of well-wishers, splashes of red burst into view and the talking drum beats out its decree. Basking in a charged clamor where the senses blur in clouds of dust, Mwata gracefully sways from side to side, jangling the beads and cowries on the back of his akatasa crown. It is on this day that the Lunda-Kazembe Crown moves.
- Full Text:
- Date Issued: 2013
A maturing manifesto: the constitutionalisation of children’s rights in South African jurisprudence 2007-2012
- Sloth-Nielsen, Julia, Kruuse, Helen
- Authors: Sloth-Nielsen, Julia , Kruuse, Helen
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68972 , vital:29344 , http://dx.doi.org/10.1163/15718182-02102005
- Description: Pre-print , This article represents the next in a series of five-year overviews of children’s rights in the courts in South Africa. Using the Convention on the Rights of the Child and the African Charter on the Welfare of Children as a point of departure, the study suggests that it is in the public sphere that children’s rights have had their most impact in the period under review. The article highlights eight areas of distinction in this five-year period: these include judicial approval of resource mobilisation for the fulfilment of children’s rights, emphasis on the quality of and standards in education; the development of innovative remedies to deal with unreasonable state measures affecting children, and an increasing focus on the right to dignity of the child. The authors conclude that the scope of the cases cited points to the growing insertion of children’s rights considerations in increasingly diverse areas of legal interaction. Furthermore, the authors posit that the CRC and ACRWC – together with non-binding sources of international law – have substantively informed and enriched the jurisprudence of South African courts.
- Full Text:
- Date Issued: 2013
- Authors: Sloth-Nielsen, Julia , Kruuse, Helen
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68972 , vital:29344 , http://dx.doi.org/10.1163/15718182-02102005
- Description: Pre-print , This article represents the next in a series of five-year overviews of children’s rights in the courts in South Africa. Using the Convention on the Rights of the Child and the African Charter on the Welfare of Children as a point of departure, the study suggests that it is in the public sphere that children’s rights have had their most impact in the period under review. The article highlights eight areas of distinction in this five-year period: these include judicial approval of resource mobilisation for the fulfilment of children’s rights, emphasis on the quality of and standards in education; the development of innovative remedies to deal with unreasonable state measures affecting children, and an increasing focus on the right to dignity of the child. The authors conclude that the scope of the cases cited points to the growing insertion of children’s rights considerations in increasingly diverse areas of legal interaction. Furthermore, the authors posit that the CRC and ACRWC – together with non-binding sources of international law – have substantively informed and enriched the jurisprudence of South African courts.
- Full Text:
- Date Issued: 2013
A proposed schema for the conditions of creativity in fine art studio practice
- Authors: Belluigi, Dina Z
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/64641 , vital:28584 , http://www.ijea.org/v14n19/index.html
- Description: Drawing from creativity and art research, this paper proposes a schema for the conditions for creativity in fine art studio practice. Discussion focuses on how the triad of creative person, artmaking process, and artwork is constructed, and the situating of this creative triad within an enabling environment, which on a structural level includes the curriculum, and on a cultural and agential level involves teaching and learning relationships. An emphasis in placed on affective concerns, particularly the role of uncertainty as an important part of the art student’s learning experience.
- Full Text:
- Date Issued: 2013
- Authors: Belluigi, Dina Z
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/64641 , vital:28584 , http://www.ijea.org/v14n19/index.html
- Description: Drawing from creativity and art research, this paper proposes a schema for the conditions for creativity in fine art studio practice. Discussion focuses on how the triad of creative person, artmaking process, and artwork is constructed, and the situating of this creative triad within an enabling environment, which on a structural level includes the curriculum, and on a cultural and agential level involves teaching and learning relationships. An emphasis in placed on affective concerns, particularly the role of uncertainty as an important part of the art student’s learning experience.
- Full Text:
- Date Issued: 2013
A qualitative ecological risk assessment of the invasive Nile tilapia, Oreochromis niloticus in a sub-tropical African river system (Limpopo River, South Africa)
- Zengeya, Tsungai A, Robertson, Mark P, Booth, Anthony J, Chimimba, Christian T
- Authors: Zengeya, Tsungai A , Robertson, Mark P , Booth, Anthony J , Chimimba, Christian T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123575 , vital:35457 , https://doi.10.1002/aqc.2258
- Description: 1. This study outlines the development of a qualitative risk assessment method and its application as a screening tool for determining the risk of establishment and spread of the invasive Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), within the central sub-catchment of the Limpopo River basin in northern South Africa. 2. The assessment used known physiological tolerance limits of O. niloticus in relation to minimum water temperature, presence or absence of dams, seasonality of river flows, and the presence of indigenous fish species of concern to identify river systems that would be suitable for O. niloticus establishment. 3. River sections along the Limpopo main river channel and the immediate reaches of its associated tributaries east of the Limpopo/Lephalala river confluence along the Botswana–South Africa–Zimbabwe border were identified as being highly vulnerable to O. niloticus invasion. Rivers in the upper Bushveld catchment (Upper Limpopo, Mogalakwena, Lephalala, Mokolo, Matlabas and Crocodile rivers) were categorized as of medium ecological risk, while headwater streams were considered to be of low ecological risk. The decrease in vulnerability between lowveld and highveld river sections was mainly a function of low water temperatures (8–12˚C) associated with increasing altitude. 4. Oreochromis niloticus is already established in the lower catchment of the Limpopo River basin where indigenous congenerics are at an extinction risk through hybridization and competition exclusion. Oreochromis niloticus, therefore, poses an ecologically unacceptable risk to river systems in the upper catchment where it is yet to establish. The current risk assessment model provides a useful preliminary framework for the identification of river systems that are vulnerable to an O. niloticus invasion where conservation measures should be directed and implemented to prevent its introduction and spread within the Limpopo river system.
- Full Text:
- Date Issued: 2013
- Authors: Zengeya, Tsungai A , Robertson, Mark P , Booth, Anthony J , Chimimba, Christian T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123575 , vital:35457 , https://doi.10.1002/aqc.2258
- Description: 1. This study outlines the development of a qualitative risk assessment method and its application as a screening tool for determining the risk of establishment and spread of the invasive Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), within the central sub-catchment of the Limpopo River basin in northern South Africa. 2. The assessment used known physiological tolerance limits of O. niloticus in relation to minimum water temperature, presence or absence of dams, seasonality of river flows, and the presence of indigenous fish species of concern to identify river systems that would be suitable for O. niloticus establishment. 3. River sections along the Limpopo main river channel and the immediate reaches of its associated tributaries east of the Limpopo/Lephalala river confluence along the Botswana–South Africa–Zimbabwe border were identified as being highly vulnerable to O. niloticus invasion. Rivers in the upper Bushveld catchment (Upper Limpopo, Mogalakwena, Lephalala, Mokolo, Matlabas and Crocodile rivers) were categorized as of medium ecological risk, while headwater streams were considered to be of low ecological risk. The decrease in vulnerability between lowveld and highveld river sections was mainly a function of low water temperatures (8–12˚C) associated with increasing altitude. 4. Oreochromis niloticus is already established in the lower catchment of the Limpopo River basin where indigenous congenerics are at an extinction risk through hybridization and competition exclusion. Oreochromis niloticus, therefore, poses an ecologically unacceptable risk to river systems in the upper catchment where it is yet to establish. The current risk assessment model provides a useful preliminary framework for the identification of river systems that are vulnerable to an O. niloticus invasion where conservation measures should be directed and implemented to prevent its introduction and spread within the Limpopo river system.
- Full Text:
- Date Issued: 2013
A ring-closing metathesis approach to eight-membered benzannelated scaffolds and subsequent internal alkene isomerizations
- Taher, Abu, Aderibigbe, Blessing A, Morgans, Garreth L, Madeley, Lee G, Khanye, Setshaba D, Van der Westhuizen, Leandi, Fernandes, Manuel A, Smith, Vincent J, Michael, Joseph P, Green, Ivan R, Van Otterlo, Willem A L
- Authors: Taher, Abu , Aderibigbe, Blessing A , Morgans, Garreth L , Madeley, Lee G , Khanye, Setshaba D , Van der Westhuizen, Leandi , Fernandes, Manuel A , Smith, Vincent J , Michael, Joseph P , Green, Ivan R , Van Otterlo, Willem A L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66252 , vital:28925 , https://doi.org/10.1016/j.tet.2012.12.043
- Description: publisher version , A set of eight-membered benzannelated heterocycles containing two heteroatoms (O,O, NR,NR and O,NR where R=protecting group) was synthesized by ring-closing metathesis from the corresponding ortho-bis-allyl precursors. In this manner, 7-methoxy-2,5-dihydro-1,6-benzodioxocine, 1,2,5,6-tetrahydro-1,6-benzodiazocines, 5,6-dihydro-2H-1,6-benzoxazocines and 5,6,9,10-tetrahydropyrido[2,3-b][1,4]diazocine were synthesized. A number of these compounds were then treated with the catalyst [RuClH(CO)(PPh3)3] to facilitate isomerization of the alkene into conjugation with the heteroatoms in the eight-membered ring. Quite surprisingly, an equal ratio of regioisomers was obtained, even if the heteroatoms were different.
- Full Text: false
- Date Issued: 2013
- Authors: Taher, Abu , Aderibigbe, Blessing A , Morgans, Garreth L , Madeley, Lee G , Khanye, Setshaba D , Van der Westhuizen, Leandi , Fernandes, Manuel A , Smith, Vincent J , Michael, Joseph P , Green, Ivan R , Van Otterlo, Willem A L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66252 , vital:28925 , https://doi.org/10.1016/j.tet.2012.12.043
- Description: publisher version , A set of eight-membered benzannelated heterocycles containing two heteroatoms (O,O, NR,NR and O,NR where R=protecting group) was synthesized by ring-closing metathesis from the corresponding ortho-bis-allyl precursors. In this manner, 7-methoxy-2,5-dihydro-1,6-benzodioxocine, 1,2,5,6-tetrahydro-1,6-benzodiazocines, 5,6-dihydro-2H-1,6-benzoxazocines and 5,6,9,10-tetrahydropyrido[2,3-b][1,4]diazocine were synthesized. A number of these compounds were then treated with the catalyst [RuClH(CO)(PPh3)3] to facilitate isomerization of the alkene into conjugation with the heteroatoms in the eight-membered ring. Quite surprisingly, an equal ratio of regioisomers was obtained, even if the heteroatoms were different.
- Full Text: false
- Date Issued: 2013
A study of the photophysicochemical and antimicrobial properties of two zinc phthalocyanine–silver nanoparticle conjugates
- Rapulenyane, Nomasonto, Antunes, Edith M, Nyokong, Tebello
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232522 , vital:49999 , xlink:href="https://doi.org/10.1039/C3NJ41107A"
- Description: This work reports conjugation of two mono carboxy substituted zinc phthalocyanines with glutathione capped silver nanoparticles (GSH-AgNPs). The photophysicochemical behaviour of the novel phthalocyanines–silver nanoparticle conjugates was investigated together with simple mixtures of the silver nanoparticles with low symmetry phthalocyanines (i.e. with no direct chemical bond formation). It was observed that upon conjugation of the phthalocyanines to the silver nanoparticles, a blue shifting of the Q band was induced. The triplet lifetimes and quantum yields improved upon conjugation as compared to the phthalocyanines alone. Fluorescence lifetimes and quantum yields decreased for conjugates compared to the phthalocyanines alone due to quenching caused by the silver nanoparticles. The low symmetry phthalocyanines and their conjugates showed antimicrobial activity against Escherichia coli in the presence and absence of light.
- Full Text:
- Date Issued: 2013
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232522 , vital:49999 , xlink:href="https://doi.org/10.1039/C3NJ41107A"
- Description: This work reports conjugation of two mono carboxy substituted zinc phthalocyanines with glutathione capped silver nanoparticles (GSH-AgNPs). The photophysicochemical behaviour of the novel phthalocyanines–silver nanoparticle conjugates was investigated together with simple mixtures of the silver nanoparticles with low symmetry phthalocyanines (i.e. with no direct chemical bond formation). It was observed that upon conjugation of the phthalocyanines to the silver nanoparticles, a blue shifting of the Q band was induced. The triplet lifetimes and quantum yields improved upon conjugation as compared to the phthalocyanines alone. Fluorescence lifetimes and quantum yields decreased for conjugates compared to the phthalocyanines alone due to quenching caused by the silver nanoparticles. The low symmetry phthalocyanines and their conjugates showed antimicrobial activity against Escherichia coli in the presence and absence of light.
- Full Text:
- Date Issued: 2013
A tale of two neglected systems-structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves
- Authors: Botha, Christiaan E J
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6499 , http://hdl.handle.net/10962/d1004514 , http://dx.doi.org/10.3389/fpls.2013.00297
- Description: There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.
- Full Text:
- Date Issued: 2013
- Authors: Botha, Christiaan E J
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6499 , http://hdl.handle.net/10962/d1004514 , http://dx.doi.org/10.3389/fpls.2013.00297
- Description: There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.
- Full Text:
- Date Issued: 2013
Academic freedom and the enclosure of knowledge in the global university
- Authors: Federici, Sylvia
- Date: 2013
- Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education and state -- South Africa Education, Higher -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/773 , vital:19989
- Description: A discussion of 'academic freedom' is timely as everywhere, across the planet, this long fought-for principle is under siege. Trends, already emerging in Africa in the 1980s, are extending to every part of the world, contributing to what we can call 'a global enclosure of knowledge. ' This is the restriction of access to education to the 'happy few,' as knowledge and education are becoming commodified and profitability is becoming the sole logic by which the university is structured. Here I examine the most salient ways in which academic freedom is affected by these developments (with special reference to the United States) and, most important, how we can resist them. First, however, I consider what we mean by 'academic freedom,' since it is a concept that has been evolving, taking on new meanings, and is presently used with different connotations.
- Full Text:
- Date Issued: 2013
- Authors: Federici, Sylvia
- Date: 2013
- Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education and state -- South Africa Education, Higher -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/773 , vital:19989
- Description: A discussion of 'academic freedom' is timely as everywhere, across the planet, this long fought-for principle is under siege. Trends, already emerging in Africa in the 1980s, are extending to every part of the world, contributing to what we can call 'a global enclosure of knowledge. ' This is the restriction of access to education to the 'happy few,' as knowledge and education are becoming commodified and profitability is becoming the sole logic by which the university is structured. Here I examine the most salient ways in which academic freedom is affected by these developments (with special reference to the United States) and, most important, how we can resist them. First, however, I consider what we mean by 'academic freedom,' since it is a concept that has been evolving, taking on new meanings, and is presently used with different connotations.
- Full Text:
- Date Issued: 2013
Adsorption and separation of platinum and palladium by polyamine functionalized polystyrene-based beads and nanofibers
- Fayemi, Omolola E, Ogunlaja, Adeniyi S, Kempgens, Pierre F M, Antunes, Edith M, Torto, Nelson, Nyokong, Tebello, Tshentu, Zenixole R
- Authors: Fayemi, Omolola E , Ogunlaja, Adeniyi S , Kempgens, Pierre F M , Antunes, Edith M , Torto, Nelson , Nyokong, Tebello , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241694 , vital:50961 , xlink:href="https://doi.org/10.1016/j.mineng.2013.06.006"
- Description: Adsorption and separation of platinum and palladium chlorido species (PtCl62- and PdCl42-) on polystyrene beads as well as nanofibers functionalized with ammonium centres based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tris-(2-aminoethyl)amine (TAEA) are described. The functionalized sorbent materials were characterized by microanalysis, SEM, XPS, BET and FTIR. The surface area of the functionalized fibers was in the range 69–241 m2/g while it was 73–107 m2/g for the beads. The adsorption and loading capacities of the sorption materials were investigated using both the batch and column studies at 1 M HCl concentration. The adsorption studies for both PtCl62- and PdCl42- on the different sorbent materials fit the Langmuir isotherm with R2 values >0.99. The highest loading capacity of Pt and Pd were 7.4 mg/g and 4.3 mg/g respectively for the nanofiber sorbent material based on ethylenediamine (EDA) while the beads with ethylenediamine (EDA) gave 1.0 mg/g and 0.2 mg/g for Pt and Pd respectively. Metals loaded on the sorbent materials were recovered by using 3% m/v thiourea solution as the eluting agent with quantitative desorption efficiency under the selected experimental conditions. Separation of platinum from palladium was partially achieved by selective stripping of PtCl62- with 0.5 M of NaClO4 in 1.0 M HCl while PdCl42- was eluted with 0.5 M thiourea in 1.0 M HCl. Separation of platinum from iridium and rhodium under 1 M HCl concentration was successful on triethylenetriamine (TETA)-functionalized Merrifield beads. This material (M-TETA) showed selectivity for platinum albeit the low loading capacity.
- Full Text:
- Date Issued: 2013
- Authors: Fayemi, Omolola E , Ogunlaja, Adeniyi S , Kempgens, Pierre F M , Antunes, Edith M , Torto, Nelson , Nyokong, Tebello , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241694 , vital:50961 , xlink:href="https://doi.org/10.1016/j.mineng.2013.06.006"
- Description: Adsorption and separation of platinum and palladium chlorido species (PtCl62- and PdCl42-) on polystyrene beads as well as nanofibers functionalized with ammonium centres based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tris-(2-aminoethyl)amine (TAEA) are described. The functionalized sorbent materials were characterized by microanalysis, SEM, XPS, BET and FTIR. The surface area of the functionalized fibers was in the range 69–241 m2/g while it was 73–107 m2/g for the beads. The adsorption and loading capacities of the sorption materials were investigated using both the batch and column studies at 1 M HCl concentration. The adsorption studies for both PtCl62- and PdCl42- on the different sorbent materials fit the Langmuir isotherm with R2 values >0.99. The highest loading capacity of Pt and Pd were 7.4 mg/g and 4.3 mg/g respectively for the nanofiber sorbent material based on ethylenediamine (EDA) while the beads with ethylenediamine (EDA) gave 1.0 mg/g and 0.2 mg/g for Pt and Pd respectively. Metals loaded on the sorbent materials were recovered by using 3% m/v thiourea solution as the eluting agent with quantitative desorption efficiency under the selected experimental conditions. Separation of platinum from palladium was partially achieved by selective stripping of PtCl62- with 0.5 M of NaClO4 in 1.0 M HCl while PdCl42- was eluted with 0.5 M thiourea in 1.0 M HCl. Separation of platinum from iridium and rhodium under 1 M HCl concentration was successful on triethylenetriamine (TETA)-functionalized Merrifield beads. This material (M-TETA) showed selectivity for platinum albeit the low loading capacity.
- Full Text:
- Date Issued: 2013
Alternative/Experimental art spaces in Johannesburg:
- Authors: Malatjie, Portia
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147692 , vital:38661 , https://0-doi.org.wam.seals.ac.za/10.1080/09528822.2013.798181
- Description: There are a number of recent exciting developments in the Johannesburg alternative art scene. Alternative or experimental art spaces often exist as an alternative to commercial galleries and government or privately funded galleries as well as museums. They are therefore governed through a different set of rules, rules that often aim to transgress the institutional. These spaces, including the Parking Gallery, the Keleketla! Library and arguably the Wits School of Art's Substation gallery, invite debates about alternative art programming, collaborative art making and the necessity of institutional funding in order to maintain such spaces. In addition to these questions, it is pertinent to first determine what it is that classifies a space as alternative.
- Full Text:
- Date Issued: 2013
- Authors: Malatjie, Portia
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147692 , vital:38661 , https://0-doi.org.wam.seals.ac.za/10.1080/09528822.2013.798181
- Description: There are a number of recent exciting developments in the Johannesburg alternative art scene. Alternative or experimental art spaces often exist as an alternative to commercial galleries and government or privately funded galleries as well as museums. They are therefore governed through a different set of rules, rules that often aim to transgress the institutional. These spaces, including the Parking Gallery, the Keleketla! Library and arguably the Wits School of Art's Substation gallery, invite debates about alternative art programming, collaborative art making and the necessity of institutional funding in order to maintain such spaces. In addition to these questions, it is pertinent to first determine what it is that classifies a space as alternative.
- Full Text:
- Date Issued: 2013
An analysis of the distribution and use of teaching aids in mathematics in selected Windhoek secondary schools
- Authors: Dzambara, Tobias Munyaradzi
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Namibia Teaching -- Aids and devices -- Research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1344 , http://hdl.handle.net/10962/d1001410
- Description: This study investigates the types of mathematics teaching aids available at both public and private secondary schools in Windhoek. The study characterises their usage and source as well as teachers’ perceptions towards the use of such teaching resources in the Mathematics classroom. The study is grounded in an interpretive paradigm and employed a mixed methods approach to generate both quantitative and qualitative data in two sequential phases. Phase 1 of the research process, which involved 75 Mathematics teachers, took the form of an audit of the availability and use of teaching aids at 25 secondary schools in Windhoek. A case study methodology was adopted in Phase 2 which focused on five purposively selected schools that displayed different characteristics in terms of the availability of teaching resources. The study found that the majority of teachers at secondary schools in Windhoek have a positive attitude towards the importance and role of teaching aids in Mathematics, seeing them as promoters of hands-on engagement, visual reasoning, active participation and motivation amongst learners. However, in some instances schools are underresourced with respect to certain types of teaching aids, specifically graph boards, geoboards, geometric models and computers. A need for appropriate in-school support on the use of teaching aids was also identified
- Full Text:
- Date Issued: 2013
- Authors: Dzambara, Tobias Munyaradzi
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Namibia Teaching -- Aids and devices -- Research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1344 , http://hdl.handle.net/10962/d1001410
- Description: This study investigates the types of mathematics teaching aids available at both public and private secondary schools in Windhoek. The study characterises their usage and source as well as teachers’ perceptions towards the use of such teaching resources in the Mathematics classroom. The study is grounded in an interpretive paradigm and employed a mixed methods approach to generate both quantitative and qualitative data in two sequential phases. Phase 1 of the research process, which involved 75 Mathematics teachers, took the form of an audit of the availability and use of teaching aids at 25 secondary schools in Windhoek. A case study methodology was adopted in Phase 2 which focused on five purposively selected schools that displayed different characteristics in terms of the availability of teaching resources. The study found that the majority of teachers at secondary schools in Windhoek have a positive attitude towards the importance and role of teaching aids in Mathematics, seeing them as promoters of hands-on engagement, visual reasoning, active participation and motivation amongst learners. However, in some instances schools are underresourced with respect to certain types of teaching aids, specifically graph boards, geoboards, geometric models and computers. A need for appropriate in-school support on the use of teaching aids was also identified
- Full Text:
- Date Issued: 2013
An exploratory study of the impacts of climate variability on food production availability and access in Chivi district 6, Zimbabwe
- Authors: Gwindi, Raphael
- Date: 2013
- Subjects: Climatic changes , Food security , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26696 , vital:65852
- Description: The impacts of climate variability have been of global concern for many years. These impacts are affecting economic, social, cultural, agricultural, health and political structures in different countries. Although the impacts of climate variability on agricultural production are being experienced globally, it is generally accepted that developing countries are the worst affected due to a variety of reasons. Given the high susceptibility of developing countries to climate variability, this study maps and analyses the impacts of climate variability on agricultural production, food production, availability and access in Chivi District, Zimbabwe. The study aimed at finding out experiences, so it used a qualitative approach. The study uses in-depth and focus group discussions to collect data. Chivi district is experiencing erratic weather patterns which are impacting agricultural production in general and food production in particular. Consequently, food availability and access is on the decline in the district. Even though smallholder farmers have devised coping and adaptation strategies, this is not sufficient to help them fully deal with the impacts of climate variability. This is due to their limited assets, inadequate technology and climate information among other things. In an attempt to assist these smallholder farmers cope and adapt to the impacts of climate variability, NGOs and Government Departments have instituted a number of community interventions. This assistance includes agricultural extension services, farming input support and provision of climate change information and a lot of other things. In view of these findings, the study recommends the universal adoption and growing of small grain drought resistant crops in climate variability affected Chivi. It further recommends that farmers adopt conservation agriculture, get into partnerships and co-operatives to practice irrigation gardening where those without water sources provide equipment, labour and knowledge. The study also recommends that more climate science research be conducted in Zimbabwe by both NGOs and Government Departments. Furthermore, government and NGOs should provide more support for farmers in the form of climate change related training, knowledge and technology transfer among other things. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2013
- Full Text:
- Date Issued: 2013
- Authors: Gwindi, Raphael
- Date: 2013
- Subjects: Climatic changes , Food security , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26696 , vital:65852
- Description: The impacts of climate variability have been of global concern for many years. These impacts are affecting economic, social, cultural, agricultural, health and political structures in different countries. Although the impacts of climate variability on agricultural production are being experienced globally, it is generally accepted that developing countries are the worst affected due to a variety of reasons. Given the high susceptibility of developing countries to climate variability, this study maps and analyses the impacts of climate variability on agricultural production, food production, availability and access in Chivi District, Zimbabwe. The study aimed at finding out experiences, so it used a qualitative approach. The study uses in-depth and focus group discussions to collect data. Chivi district is experiencing erratic weather patterns which are impacting agricultural production in general and food production in particular. Consequently, food availability and access is on the decline in the district. Even though smallholder farmers have devised coping and adaptation strategies, this is not sufficient to help them fully deal with the impacts of climate variability. This is due to their limited assets, inadequate technology and climate information among other things. In an attempt to assist these smallholder farmers cope and adapt to the impacts of climate variability, NGOs and Government Departments have instituted a number of community interventions. This assistance includes agricultural extension services, farming input support and provision of climate change information and a lot of other things. In view of these findings, the study recommends the universal adoption and growing of small grain drought resistant crops in climate variability affected Chivi. It further recommends that farmers adopt conservation agriculture, get into partnerships and co-operatives to practice irrigation gardening where those without water sources provide equipment, labour and knowledge. The study also recommends that more climate science research be conducted in Zimbabwe by both NGOs and Government Departments. Furthermore, government and NGOs should provide more support for farmers in the form of climate change related training, knowledge and technology transfer among other things. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2013
- Full Text:
- Date Issued: 2013
An invader within an altered landscape: one catfish, two rivers and an inter-basin water transfer scheme
- Kadye, Wilbert T, Booth, Anthony J
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123776 , vital:35494 , https://doi.10.1002/rra.2599
- Description: African sharptooth catfish Clarias gariepinus has become established as a non-native invasive species in Eastern Cape, South Africa, where it was translocated primarily through an inter-basin water transfer scheme into the Great Fish and Sundays rivers. This study examined the patterns in catfish distribution and abundance, and compared trophic niches in relation to the ichthyofauna of the two rivers. Correspondence analysis revealed upstream to downstream gradients associated with the spatial distribution in species richness for most species within the mainstream and mainstream to tributary gradients that were associated mostly with the spatial distribution of native minnows in both rivers. Catfish was predicted to occur widely within the mainstream habitats and to decrease progressively from mainstreams to tributaries. Based on classification and regression trees, the physico-chemical environment was found to be a good proxy for predicting the occurrence and abundance of catfish. Although non-significant relationships were observed between catfish and other native fish species abundances, the study suggests potential impact due to predation and interference in habitats where the invader co-occurs with other fishes. Comparisons of trophic niches indicated higher trophic diversity for the mainstream ichthyofauna than the tributary communities in both rivers, suggesting an upstream to downstream continuum in community structure and resource availability. Catfish within the invaded mainstream had comparable trophic niches and similar dispersion patterns among individuals for both rivers, but indicated differences in shapes of scatter. This suggests that the catfish exhibited a differential response, probably in relation to resource availability, that may be indicative of its dietary plasticity. The study suggests the proliferation of catfish and its probable impact within the mainstream flow-altered habitats where invasion resistance was possibly reduced. Comparisons of trophic niches provided information on its probable impact at different scales and the potential risk of invasion of tributaries inhabited by native minnow species.
- Full Text:
- Date Issued: 2013
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123776 , vital:35494 , https://doi.10.1002/rra.2599
- Description: African sharptooth catfish Clarias gariepinus has become established as a non-native invasive species in Eastern Cape, South Africa, where it was translocated primarily through an inter-basin water transfer scheme into the Great Fish and Sundays rivers. This study examined the patterns in catfish distribution and abundance, and compared trophic niches in relation to the ichthyofauna of the two rivers. Correspondence analysis revealed upstream to downstream gradients associated with the spatial distribution in species richness for most species within the mainstream and mainstream to tributary gradients that were associated mostly with the spatial distribution of native minnows in both rivers. Catfish was predicted to occur widely within the mainstream habitats and to decrease progressively from mainstreams to tributaries. Based on classification and regression trees, the physico-chemical environment was found to be a good proxy for predicting the occurrence and abundance of catfish. Although non-significant relationships were observed between catfish and other native fish species abundances, the study suggests potential impact due to predation and interference in habitats where the invader co-occurs with other fishes. Comparisons of trophic niches indicated higher trophic diversity for the mainstream ichthyofauna than the tributary communities in both rivers, suggesting an upstream to downstream continuum in community structure and resource availability. Catfish within the invaded mainstream had comparable trophic niches and similar dispersion patterns among individuals for both rivers, but indicated differences in shapes of scatter. This suggests that the catfish exhibited a differential response, probably in relation to resource availability, that may be indicative of its dietary plasticity. The study suggests the proliferation of catfish and its probable impact within the mainstream flow-altered habitats where invasion resistance was possibly reduced. Comparisons of trophic niches provided information on its probable impact at different scales and the potential risk of invasion of tributaries inhabited by native minnow species.
- Full Text:
- Date Issued: 2013
An investigation of the discursive construction of the Tanganyika-Zanzibar Union as nation in the Union Day coverage in The Citizen and Daily News newspapers from 2005 to 2011
- Authors: Dotto, Paul Casmir Kuhenga
- Date: 2013
- Subjects: Newspapers -- Research -- Tanzania , Press and politics -- Tanzania , Tanzania -- Politics and government -- 1964- , Zanzibar -- Politics and government -- 1964- , Press , Daily News , The Citizen , Union Day , Nation building
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3412 , http://hdl.handle.net/10962/d1001843
- Description: This study is concerned with the constructions of the Tanzanian nation in the press. It has confined its focus, first, to the coverage from 2005 to 2011 on Union Day that marks the Union between Tanganyika and Zanzibar and the formation of the United Republic of Tanzania and, second, to two prominent Tanzanian newspapers, namely the state-owned Daily News, and the privately-owned The Citizen on Union Day. As the Union remains a contentious issue, the relevance of this research relates to the press’s considerable power to shape understandings and influence attitudes. The study works within a broad cultural and media studies framework and is informed by a constructionist approach to representation and to culture, and to nation in particular. It also draws of journalistic theories of agenda-setting and the normative roles of the press to probe the agendas set by the press on Union Day and to interrogate how the two newspapers construct and frame the Union of Tanganyika and Zanzibar as nation. The research responds to the question: ‘How has the Tanganyika-Zanzibar Union been represented in The Citizen and Daily News newspapers from 2005 to 2011?’ It employs quantitative and qualitative (thematic) content analysis to investigate the coverage in the editorials and feature articles of The Citizen and Daily News newspapers on Union Day (26 April) of 2005 to 2011. This study finds that the government-owned newspaper, Daily News, publishes more articles related to Union on Union Day than the privately-owned, The Citizen and collaborates more determinedly with the state in the process of constructing the nation. However, both newspapers adopt a collaborative role consistent with the development journalism tradition that endorses an informal partnership between media and the state in the process of development (Christians et al, 2009:201). Both publications tend to emphasise the hegemonic ideology pertaining to Union while giving limited attention to challenges to such constructions. While both newspapers do identify certain problems of the Union and thus exercise a monitorial role to varying extents, it is apparent that the press in Tanzania tends to be largely acritical, perhaps attributable to a long period under single party rule
- Full Text:
- Date Issued: 2013
- Authors: Dotto, Paul Casmir Kuhenga
- Date: 2013
- Subjects: Newspapers -- Research -- Tanzania , Press and politics -- Tanzania , Tanzania -- Politics and government -- 1964- , Zanzibar -- Politics and government -- 1964- , Press , Daily News , The Citizen , Union Day , Nation building
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3412 , http://hdl.handle.net/10962/d1001843
- Description: This study is concerned with the constructions of the Tanzanian nation in the press. It has confined its focus, first, to the coverage from 2005 to 2011 on Union Day that marks the Union between Tanganyika and Zanzibar and the formation of the United Republic of Tanzania and, second, to two prominent Tanzanian newspapers, namely the state-owned Daily News, and the privately-owned The Citizen on Union Day. As the Union remains a contentious issue, the relevance of this research relates to the press’s considerable power to shape understandings and influence attitudes. The study works within a broad cultural and media studies framework and is informed by a constructionist approach to representation and to culture, and to nation in particular. It also draws of journalistic theories of agenda-setting and the normative roles of the press to probe the agendas set by the press on Union Day and to interrogate how the two newspapers construct and frame the Union of Tanganyika and Zanzibar as nation. The research responds to the question: ‘How has the Tanganyika-Zanzibar Union been represented in The Citizen and Daily News newspapers from 2005 to 2011?’ It employs quantitative and qualitative (thematic) content analysis to investigate the coverage in the editorials and feature articles of The Citizen and Daily News newspapers on Union Day (26 April) of 2005 to 2011. This study finds that the government-owned newspaper, Daily News, publishes more articles related to Union on Union Day than the privately-owned, The Citizen and collaborates more determinedly with the state in the process of constructing the nation. However, both newspapers adopt a collaborative role consistent with the development journalism tradition that endorses an informal partnership between media and the state in the process of development (Christians et al, 2009:201). Both publications tend to emphasise the hegemonic ideology pertaining to Union while giving limited attention to challenges to such constructions. While both newspapers do identify certain problems of the Union and thus exercise a monitorial role to varying extents, it is apparent that the press in Tanzania tends to be largely acritical, perhaps attributable to a long period under single party rule
- Full Text:
- Date Issued: 2013
An overview of normative frameworks for the protection of development-induced IDPs in Kenya.
- Authors: Juma, Laurence
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127112 , vital:35957 , https://doi.org/10.1163/17087384-12342016
- Description: Based on the assumption that development induced displacement brings new challenges that the existing protection frameworks may not be aptly suited to deal with, this article analyses how the existing laws have met this challenge and the prospects for further improvement. While its focus is on Kenya, it evaluates the normative quality of protection and standards offered by regional instruments against the existing, as well emerging, parameters for implementation at the domestic level. In this regard, the article examines the propriety of Kenya’s newly promulgated law on internal displacement in providing for protection for the development induced IDPs, the implementation programme that it establishes and its prospects for furthering the vision of the UN Guiding Principles on Internally Displaced and other regional instruments.
- Full Text:
- Date Issued: 2013
- Authors: Juma, Laurence
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127112 , vital:35957 , https://doi.org/10.1163/17087384-12342016
- Description: Based on the assumption that development induced displacement brings new challenges that the existing protection frameworks may not be aptly suited to deal with, this article analyses how the existing laws have met this challenge and the prospects for further improvement. While its focus is on Kenya, it evaluates the normative quality of protection and standards offered by regional instruments against the existing, as well emerging, parameters for implementation at the domestic level. In this regard, the article examines the propriety of Kenya’s newly promulgated law on internal displacement in providing for protection for the development induced IDPs, the implementation programme that it establishes and its prospects for furthering the vision of the UN Guiding Principles on Internally Displaced and other regional instruments.
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- Date Issued: 2013