'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
6-Hydroxymelatonin protects against cyanide induced oxidative stress in rat brain homogenates
- Maharaj, Deepa S, Walker, Roderick B, Glass, Beverley D, Daya, Santylal
- Authors: Maharaj, Deepa S , Walker, Roderick B , Glass, Beverley D , Daya, Santylal
- Date: 2003
- Language: English
- Type: Article , text
- Identifier: vital:6405 , http://hdl.handle.net/10962/d1006478
- Description: Both 6-hydroxymelatonin and N-acetyl-N-formyl-5-methoxykynurenamine are photodegradants and enzymatic metabolites of melatonin and are known to retain equipotent activity against potassium cyanide-induced superoxide generation compared to melatonin. It is not clear whether one or both of these metabolites is responsible for this effect. The present study therefore investigates the possible manner in which 6-hydroxymelatonin protects against oxidative stress induced by cyanide in rat brain homogenates. We examined the ability of 6-hydroxymelatonin to scavenge KCN-induced superoxide anion generation as well as lipid peroxidation. In addition, we also examined the effect of this indole on lactate dehydrogenase activity (LDH) as well as mitochondrial electron transport using dichlorophenol–indophenol as an electron acceptor. The results of this study show that 6-hydroxymelatonin significantly reduces KCN-induced superoxide anion generation, which is accompanied by a commensurate reduction in lipid peroxidation. Partial reversal of the KCN-induced reduction in mitochondrial electron transport is accompanied by a similar reversal of mitochondrial LDH activity blunted by KCN. It can thus be proposed that 6-hydroxymelatonin is potentially neuroprotective against KCN-induced neurotoxicity.
- Full Text:
- Date Issued: 2003
- Authors: Maharaj, Deepa S , Walker, Roderick B , Glass, Beverley D , Daya, Santylal
- Date: 2003
- Language: English
- Type: Article , text
- Identifier: vital:6405 , http://hdl.handle.net/10962/d1006478
- Description: Both 6-hydroxymelatonin and N-acetyl-N-formyl-5-methoxykynurenamine are photodegradants and enzymatic metabolites of melatonin and are known to retain equipotent activity against potassium cyanide-induced superoxide generation compared to melatonin. It is not clear whether one or both of these metabolites is responsible for this effect. The present study therefore investigates the possible manner in which 6-hydroxymelatonin protects against oxidative stress induced by cyanide in rat brain homogenates. We examined the ability of 6-hydroxymelatonin to scavenge KCN-induced superoxide anion generation as well as lipid peroxidation. In addition, we also examined the effect of this indole on lactate dehydrogenase activity (LDH) as well as mitochondrial electron transport using dichlorophenol–indophenol as an electron acceptor. The results of this study show that 6-hydroxymelatonin significantly reduces KCN-induced superoxide anion generation, which is accompanied by a commensurate reduction in lipid peroxidation. Partial reversal of the KCN-induced reduction in mitochondrial electron transport is accompanied by a similar reversal of mitochondrial LDH activity blunted by KCN. It can thus be proposed that 6-hydroxymelatonin is potentially neuroprotective against KCN-induced neurotoxicity.
- Full Text:
- Date Issued: 2003
A case of effective single-session treatment for attention deficit and learning problems in a routine clinical practice : the value of a transdiagnostic approach to case formulation
- Whitefield-Alexander, V, Edwards, David J A
- Authors: Whitefield-Alexander, V , Edwards, David J A
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6274 , http://hdl.handle.net/10962/d1008274
- Description: This article reports a systematic clinical case study of the psychological assessment and treatment of Daniel (9), a coloured South African boy with a diagnosis of attention deficit hyperactivity disorder (ADHD) (inattentive type). The case is of scientific interest because: (1) there was only a single treatment session, in which contingency management training was delivered to Daniel’s parents and teacher; (2) there was evidence for the effectiveness of the intervention immediately and at two-year follow-up; (3) it documents the transportability to a South African context of an intervention developed by overseas research; (4) it documents the central role of case formulation in the delivery of effective psychological interventions; and (5) although Daniel met the criteria for ADHD, he also displayed symptoms of depression and social anxiety and the case supports the use of a transdiagnostic approach to case formulation. The conscientiousness with which his parents and teachers applied the programme was a major factor in the effectiveness of the intervention, and such rapid impact would not be possible where parents and teachers are unavailable or not co-operative. The publication of systematic case studies such as this one is important for the development of a local evidence-based practice in South Africa.
- Full Text:
- Date Issued: 2009
- Authors: Whitefield-Alexander, V , Edwards, David J A
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6274 , http://hdl.handle.net/10962/d1008274
- Description: This article reports a systematic clinical case study of the psychological assessment and treatment of Daniel (9), a coloured South African boy with a diagnosis of attention deficit hyperactivity disorder (ADHD) (inattentive type). The case is of scientific interest because: (1) there was only a single treatment session, in which contingency management training was delivered to Daniel’s parents and teacher; (2) there was evidence for the effectiveness of the intervention immediately and at two-year follow-up; (3) it documents the transportability to a South African context of an intervention developed by overseas research; (4) it documents the central role of case formulation in the delivery of effective psychological interventions; and (5) although Daniel met the criteria for ADHD, he also displayed symptoms of depression and social anxiety and the case supports the use of a transdiagnostic approach to case formulation. The conscientiousness with which his parents and teachers applied the programme was a major factor in the effectiveness of the intervention, and such rapid impact would not be possible where parents and teachers are unavailable or not co-operative. The publication of systematic case studies such as this one is important for the development of a local evidence-based practice in South Africa.
- Full Text:
- Date Issued: 2009
A Case Study of Two Selected Teachers as they Integrated Dynamic Geometry Software as a Visualisation Tool in Teaching Geometry:
- Mavani, Deepak, Mavani, Beena, Schäfer, Marc
- Authors: Mavani, Deepak , Mavani, Beena , Schäfer, Marc
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141076 , vital:37942 , https://doi.org/10.1080/18117295.2018.1522716
- Description: This paper reports on an aspect of a larger research study conceptualised within a teacher development project in Mthatha, Eastern Cape Province. The project was initiated with the objective to develop appropriate skills to use dynamic geometry software (DGS) effectively and strategically as a teaching and learning tool for mathematics. The study reported in this paper aims specifically to ascertain how selected mathematics teachers integrated co-developed technologically aided visualisation tools in the observed lessons. The case study involved two teachers from different schools. The data sources were the classroom observations followed by stimulated reflective interviews with the teachers. The data were analysed to study the use of DGS visualisation tools in relation to Kilpatrick’s framework of teaching proficiency.
- Full Text:
- Date Issued: 2018
- Authors: Mavani, Deepak , Mavani, Beena , Schäfer, Marc
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141076 , vital:37942 , https://doi.org/10.1080/18117295.2018.1522716
- Description: This paper reports on an aspect of a larger research study conceptualised within a teacher development project in Mthatha, Eastern Cape Province. The project was initiated with the objective to develop appropriate skills to use dynamic geometry software (DGS) effectively and strategically as a teaching and learning tool for mathematics. The study reported in this paper aims specifically to ascertain how selected mathematics teachers integrated co-developed technologically aided visualisation tools in the observed lessons. The case study involved two teachers from different schools. The data sources were the classroom observations followed by stimulated reflective interviews with the teachers. The data were analysed to study the use of DGS visualisation tools in relation to Kilpatrick’s framework of teaching proficiency.
- Full Text:
- Date Issued: 2018
A comparative study of the dosimetric features of α-Al2O3: C, Mg and α-Al2O3: C
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/113058 , vital:33694 , https://doi.org/10.1093/rpd/ncx039
- Description: A comparative study of the dosimetric features of α-Al2O3:C,Mg and α-Al2O3:C relevant to thermoluminescence dosimetry is reported. A glow curve of α-Al2O3:C,Mg measured at 1°C/s after beta irradiation to 1 Gy shows two subsidiary peaks at 42°C (labelled as I) and 72°C (II) and the main peak at 161°C (III) whereas a glow curve of α-Al2O3:C measured under the same conditions shows the main peak at 178°C (II′) and a lower intensity peak at 48°C (I′). Apart from these ones, there are several other peaks at temperatures beyond that of the main peak in both α-Al2O3:C,Mg and α-Al2O3:C. However, the latter are not included in this study. We report a comparative quantitative analysis of dose response and fading of peaks I, II and III of α-Al2O3:C,Mg and peaks I′ and II′ of α-Al2O3:C. Analysis shows that the dose response of peaks I and III is sublinear within 1–10 Gy whereas that of peak II is superlinear within 1–4 Gy followed by a sublinear region within 4–10 Gy. In comparison, the dose response of peak I′ is superlinear within 1–4 Gy followed by a sublinear region within 4–10 Gy whereas that of peak II′ is sublinear within 1–4 Gy followed by a superlinear region within 4–10 Gy. As regards to fading corresponding to 1 Gy, peak I is very unstable and fades within 300 s, peak II is more stable and takes up to 43200 s to fade. In comparison, peak III fades down to 30% of its initial intensity within 2400 s. Interestingly, between 2400 and 800 s, the intensity fades by 17% only. Regarding fading in α-Al2O3:C, peak I′ fades within 600 s whereas peak II′ shows an inverse fading behaviour up to 64800 s. The rate of fading for peaks I, II and III in α-Al2O3:C,Mg was found to decrease with increase in dose. However, no such behaviour was observed in α-Al2O3:C. The fading in both samples is discussed on the basis of a charge hopping mechanism.
- Full Text:
- Date Issued: 2017
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/113058 , vital:33694 , https://doi.org/10.1093/rpd/ncx039
- Description: A comparative study of the dosimetric features of α-Al2O3:C,Mg and α-Al2O3:C relevant to thermoluminescence dosimetry is reported. A glow curve of α-Al2O3:C,Mg measured at 1°C/s after beta irradiation to 1 Gy shows two subsidiary peaks at 42°C (labelled as I) and 72°C (II) and the main peak at 161°C (III) whereas a glow curve of α-Al2O3:C measured under the same conditions shows the main peak at 178°C (II′) and a lower intensity peak at 48°C (I′). Apart from these ones, there are several other peaks at temperatures beyond that of the main peak in both α-Al2O3:C,Mg and α-Al2O3:C. However, the latter are not included in this study. We report a comparative quantitative analysis of dose response and fading of peaks I, II and III of α-Al2O3:C,Mg and peaks I′ and II′ of α-Al2O3:C. Analysis shows that the dose response of peaks I and III is sublinear within 1–10 Gy whereas that of peak II is superlinear within 1–4 Gy followed by a sublinear region within 4–10 Gy. In comparison, the dose response of peak I′ is superlinear within 1–4 Gy followed by a sublinear region within 4–10 Gy whereas that of peak II′ is sublinear within 1–4 Gy followed by a superlinear region within 4–10 Gy. As regards to fading corresponding to 1 Gy, peak I is very unstable and fades within 300 s, peak II is more stable and takes up to 43200 s to fade. In comparison, peak III fades down to 30% of its initial intensity within 2400 s. Interestingly, between 2400 and 800 s, the intensity fades by 17% only. Regarding fading in α-Al2O3:C, peak I′ fades within 600 s whereas peak II′ shows an inverse fading behaviour up to 64800 s. The rate of fading for peaks I, II and III in α-Al2O3:C,Mg was found to decrease with increase in dose. However, no such behaviour was observed in α-Al2O3:C. The fading in both samples is discussed on the basis of a charge hopping mechanism.
- Full Text:
- Date Issued: 2017
A framework for job creation
- NALEDI
- Authors: NALEDI
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/176037 , vital:42654
- Description: Trends and figures speak for themselves, unemployment in South Africa is clearly at crisis levels! At the heart of an effective employment creation strategy must be a conceptual framework - • before we can talk about the nuts and bolts of job creation, we need to have our basic strategies, goals and vision in place
- Full Text:
- Authors: NALEDI
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/176037 , vital:42654
- Description: Trends and figures speak for themselves, unemployment in South Africa is clearly at crisis levels! At the heart of an effective employment creation strategy must be a conceptual framework - • before we can talk about the nuts and bolts of job creation, we need to have our basic strategies, goals and vision in place
- Full Text:
A new gobiid fish, Fusigobius duospilus, from the tropical Indo-Pacific
- Hoese, Douglass F, Reader, Sally, J.L.B. Smith Institute of Ichthyology
- Authors: Hoese, Douglass F , Reader, Sally , J.L.B. Smith Institute of Ichthyology
- Date: 1985-01
- Subjects: Gobiidae -- Classification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/70180 , vital:29631 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 36 , Fusigobius duospilusis described as a new species from several localities in the tropical Pacific and Indian oceans. This species differs from other species of Fusigobius in pectoral ray and gill-raker counts, coloration, reduced pelvic frenum, branching of the pelvic rays, presence of two large black spots on the first dorsal fin and shape of the first dorsal fin. The species is free living on sand. Males average a larger size than females. Sex ratios are uneven, with about twice as many females as males. Fusigobius longispinus Goren is recorded from several localities in the western Indian Ocean, where populations differ morphologically from Red Sea populations. Fusiogobius neophytus africanusls regarded as a synonym of F. neophytus.
- Full Text:
- Date Issued: 1985-01
- Authors: Hoese, Douglass F , Reader, Sally , J.L.B. Smith Institute of Ichthyology
- Date: 1985-01
- Subjects: Gobiidae -- Classification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/70180 , vital:29631 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 36 , Fusigobius duospilusis described as a new species from several localities in the tropical Pacific and Indian oceans. This species differs from other species of Fusigobius in pectoral ray and gill-raker counts, coloration, reduced pelvic frenum, branching of the pelvic rays, presence of two large black spots on the first dorsal fin and shape of the first dorsal fin. The species is free living on sand. Males average a larger size than females. Sex ratios are uneven, with about twice as many females as males. Fusigobius longispinus Goren is recorded from several localities in the western Indian Ocean, where populations differ morphologically from Red Sea populations. Fusiogobius neophytus africanusls regarded as a synonym of F. neophytus.
- Full Text:
- Date Issued: 1985-01
A new species of Diplacanthus from the Late Devonian (Famennian) of South Africa
- Authors: Gess, Robert W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73873 , vital:30237 , https://doi.org/10.1016/S0753-3969(01)88002-2
- Description: An advanced diplacanthid (Climatiiformes) is described from a Famennian estuarine environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fin spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere.
- Full Text: false
- Date Issued: 2009
- Authors: Gess, Robert W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73873 , vital:30237 , https://doi.org/10.1016/S0753-3969(01)88002-2
- Description: An advanced diplacanthid (Climatiiformes) is described from a Famennian estuarine environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fin spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere.
- Full Text: false
- Date Issued: 2009
A preliminary investigation of spinal kinematics during sugar cane harvesting
- Authors: Todd, Andrew I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6759 , http://hdl.handle.net/10962/d1009462
- Description: The sugar cane industry forms a significant portion of the South African economy, and unlike many other countries the harvesting of sugar cane in South Africa remains manual in nature. The focus of the present study was therefore on the assessment of spinal kinematics (range of motion, velocities and accelerations in all three cardinal planes) during the harvesting process. Eight workers were recruited from the Illovo Esperanza farm in Kwa-zulu Natal as subjects for the study. The experimental protocol was conducted in situ and required subjects to cut the sugar cane using specially modified knives as they would under normal harvesting conditions. The motion performance was quantified using the lumbar motion monitor (LMM), a triaxial electrogoniometer. Results indicate that the harvesting of sugar cane places excessive demands on the spine. During cutting, subjects were required to maintain the spine in a high degree of flexion throughout the task which also demonstrated significant twisting and lateral bending. Of particular concern were the high lateral velocities (ranging between 50 and 90 m.s-1), as this is a key risk factor in the development of lower back pain. It is evident from these results that new techniques of harvesting sugar cane are essential to reduce the rate of injury within this industry.
- Full Text:
- Date Issued: 2008
- Authors: Todd, Andrew I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6759 , http://hdl.handle.net/10962/d1009462
- Description: The sugar cane industry forms a significant portion of the South African economy, and unlike many other countries the harvesting of sugar cane in South Africa remains manual in nature. The focus of the present study was therefore on the assessment of spinal kinematics (range of motion, velocities and accelerations in all three cardinal planes) during the harvesting process. Eight workers were recruited from the Illovo Esperanza farm in Kwa-zulu Natal as subjects for the study. The experimental protocol was conducted in situ and required subjects to cut the sugar cane using specially modified knives as they would under normal harvesting conditions. The motion performance was quantified using the lumbar motion monitor (LMM), a triaxial electrogoniometer. Results indicate that the harvesting of sugar cane places excessive demands on the spine. During cutting, subjects were required to maintain the spine in a high degree of flexion throughout the task which also demonstrated significant twisting and lateral bending. Of particular concern were the high lateral velocities (ranging between 50 and 90 m.s-1), as this is a key risk factor in the development of lower back pain. It is evident from these results that new techniques of harvesting sugar cane are essential to reduce the rate of injury within this industry.
- Full Text:
- Date Issued: 2008
A review of estuarine ichthyology in South Africa over the past 50 years
- Authors: Whitfield, A K
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:7155 , http://hdl.handle.net/10962/d1011873
- Description: Progress in South African estuarine ichthyology between 1946 and 1995 is reviewed. The early estuary surveys of the 1950s and 1960s resulted in the compilation of species lists for individual systems, but contained very little biological or ecological information on fishes. These surveys were superseded by both autecological and synecological studies in the 1970s and 1980s, which yielded descriptive and process-orientated information on a wide variety of species. Estuarine research during the 1990s has focused increasingly at the community level, with several review papers on the life-history styles of groups of estuarine-associated fishes being published. The last decade has also seen the departure of a number of senior estuarine ichthyologists from the field. This decline in available expertise has coincided with increased demand for ichthyological information to be used in decision support systems for the wise management and conservation of estuaries. It is suggested that these demands be seen as a challenge, with studies being directed towards providing the type of information needed for the maintenance of vital ecological processes within these systems.
- Full Text: false
- Date Issued: 1996
- Authors: Whitfield, A K
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:7155 , http://hdl.handle.net/10962/d1011873
- Description: Progress in South African estuarine ichthyology between 1946 and 1995 is reviewed. The early estuary surveys of the 1950s and 1960s resulted in the compilation of species lists for individual systems, but contained very little biological or ecological information on fishes. These surveys were superseded by both autecological and synecological studies in the 1970s and 1980s, which yielded descriptive and process-orientated information on a wide variety of species. Estuarine research during the 1990s has focused increasingly at the community level, with several review papers on the life-history styles of groups of estuarine-associated fishes being published. The last decade has also seen the departure of a number of senior estuarine ichthyologists from the field. This decline in available expertise has coincided with increased demand for ichthyological information to be used in decision support systems for the wise management and conservation of estuaries. It is suggested that these demands be seen as a challenge, with studies being directed towards providing the type of information needed for the maintenance of vital ecological processes within these systems.
- Full Text: false
- Date Issued: 1996
A snapshot of early childhood care and education in South Africa: institutional offerings, challenges and recommendations
- Authors: Harrison, Giulietta D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160312 , vital:40433 , https://doi.org/10.4102/sajce.v10i1.797
- Description: This article draws from a research report on the Project for Inclusive Early Childhood Care and Education (PIECCE), which surveyed attitudes, training strategies, materials and entrance requirements across most relevant higher education institutions (HEIs), non-governmental organisations (NGOs) and technical and vocational education and training colleges (TVETs). The aim of this study was to identify what institutions were offering in terms of training teachers in the birth-to-four age group, to identify the challenges and provide recommendations based on the findings.
- Full Text:
- Date Issued: 2020
- Authors: Harrison, Giulietta D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160312 , vital:40433 , https://doi.org/10.4102/sajce.v10i1.797
- Description: This article draws from a research report on the Project for Inclusive Early Childhood Care and Education (PIECCE), which surveyed attitudes, training strategies, materials and entrance requirements across most relevant higher education institutions (HEIs), non-governmental organisations (NGOs) and technical and vocational education and training colleges (TVETs). The aim of this study was to identify what institutions were offering in terms of training teachers in the birth-to-four age group, to identify the challenges and provide recommendations based on the findings.
- Full Text:
- Date Issued: 2020
A stability-indicating liquid chromatographic method for the analysis of erythromycin in stored biological fluids using amperometric detection
- Stubbs, Christopher, Haigh, John M, Kanfer, Isadore
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1987
- Language: English
- Type: Article
- Identifier: vital:6430 , http://hdl.handle.net/10962/d1006592
- Description: A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. This method allows both erythromycin and its principle degradation product, anhydroeythromycin, to be determined during a period of sample storage at 4 degree C and minus 15 degree C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.
- Full Text:
- Date Issued: 1987
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1987
- Language: English
- Type: Article
- Identifier: vital:6430 , http://hdl.handle.net/10962/d1006592
- Description: A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. This method allows both erythromycin and its principle degradation product, anhydroeythromycin, to be determined during a period of sample storage at 4 degree C and minus 15 degree C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.
- Full Text:
- Date Issued: 1987
Abortion in legal, social, and healthcare contexts
- Marecek, Jeanne, Macleod, Catriona I, Hoggart, Lesley
- Authors: Marecek, Jeanne , Macleod, Catriona I , Hoggart, Lesley
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68478 , vital:29262 , https://doi.org/10.1177/0959353516689521
- Description: Publisher version , From Introduction: The subject of abortion is both timely and of high relevance to feminists. In the past few months, women’s access to abortion has been contested in various parts of the world. In many countries in Latin America, the Zika outbreak raised the demand for abortions among pregnant women who had contracted (or feared contracting) the virus, with its risk of severe foetal abnormalities. In Poland, mass demonstrations by women succeeded in turning back proposed legislation prohibiting abortions. The outcome of the U.S. elections in late 2016 raised grave concerns about the future of American women’s access to abortion, which was already limited by stringent regulations and funding restrictions. We chose the title ‘‘Abortion in Context’’ to signal that we sought to publish work that moved beyond examining abortion as a ‘‘stress experience’’ encountered by individual women or as a possible precursor of mental illness. Our goal was to assemble a set of articles that would prompt readers to think critically about practices and discourses surrounding abortion. We further hoped to include work that would address the meanings and practices of abortion in the global South and among minoritized groups in the global North. We were pleased by the enthusiastic response to our Call for Papers. We note that Eklund and Purewal (2017, this issue) address abortion in China and India. Thoradeniya’s (2017, this issue) review of Abortion in Asia (Whittaker, 2010) provides a glimpse of the complex and varied practices, policies, and experiences of abortion in parts of South and Southeast Asia. Chiweshe, Mavuso, and Macleod (whose work will appear in Part 2 of the Special Issue) take up abortion in South Africa and Zimbabwe. Le Grice and Braun (whose work will also appear in Part 2), examine Maori perspectives on abortion. In this Part 1 of the Special Issue, we present work that locates abortion practices and policies in legal, social, and healthcare contexts. Women’s efforts to exercise agency with regard to bodily integrity in the context of pregnancy are shaped most obviously by the legal regulations in the jurisdictions where they live, but they are also shaped by social and cultural issues, biotechnological advances, and healthcare systems. The articles offer detailed examinations of some of these complex contextual framings of abortion.
- Full Text:
- Date Issued: 2017
- Authors: Marecek, Jeanne , Macleod, Catriona I , Hoggart, Lesley
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68478 , vital:29262 , https://doi.org/10.1177/0959353516689521
- Description: Publisher version , From Introduction: The subject of abortion is both timely and of high relevance to feminists. In the past few months, women’s access to abortion has been contested in various parts of the world. In many countries in Latin America, the Zika outbreak raised the demand for abortions among pregnant women who had contracted (or feared contracting) the virus, with its risk of severe foetal abnormalities. In Poland, mass demonstrations by women succeeded in turning back proposed legislation prohibiting abortions. The outcome of the U.S. elections in late 2016 raised grave concerns about the future of American women’s access to abortion, which was already limited by stringent regulations and funding restrictions. We chose the title ‘‘Abortion in Context’’ to signal that we sought to publish work that moved beyond examining abortion as a ‘‘stress experience’’ encountered by individual women or as a possible precursor of mental illness. Our goal was to assemble a set of articles that would prompt readers to think critically about practices and discourses surrounding abortion. We further hoped to include work that would address the meanings and practices of abortion in the global South and among minoritized groups in the global North. We were pleased by the enthusiastic response to our Call for Papers. We note that Eklund and Purewal (2017, this issue) address abortion in China and India. Thoradeniya’s (2017, this issue) review of Abortion in Asia (Whittaker, 2010) provides a glimpse of the complex and varied practices, policies, and experiences of abortion in parts of South and Southeast Asia. Chiweshe, Mavuso, and Macleod (whose work will appear in Part 2 of the Special Issue) take up abortion in South Africa and Zimbabwe. Le Grice and Braun (whose work will also appear in Part 2), examine Maori perspectives on abortion. In this Part 1 of the Special Issue, we present work that locates abortion practices and policies in legal, social, and healthcare contexts. Women’s efforts to exercise agency with regard to bodily integrity in the context of pregnancy are shaped most obviously by the legal regulations in the jurisdictions where they live, but they are also shaped by social and cultural issues, biotechnological advances, and healthcare systems. The articles offer detailed examinations of some of these complex contextual framings of abortion.
- Full Text:
- Date Issued: 2017
Academic Management and Reasoning: APR 111F
- Authors: Siziba, L P , Ndhlovu, K
- Date: 2010-07
- Language: English
- Type: Examination paper
- Identifier: vital:18256 , http://hdl.handle.net/10353/d1011250
- Description: Academic Management and Reasoning: APR 111F, Supplementary examination July 2010.
- Full Text: false
- Date Issued: 2010-07
- Authors: Siziba, L P , Ndhlovu, K
- Date: 2010-07
- Language: English
- Type: Examination paper
- Identifier: vital:18256 , http://hdl.handle.net/10353/d1011250
- Description: Academic Management and Reasoning: APR 111F, Supplementary examination July 2010.
- Full Text: false
- Date Issued: 2010-07
Academic Practice & Reasoning: APR 122F
- Authors: Siziba, L P , Makwela, N
- Date: 2011-11
- Language: English
- Type: Examination paper
- Identifier: vital:18275 , http://hdl.handle.net/10353/d1011271
- Description: Academic Practice & Reasoning: APR 122F, examination November 2011.
- Full Text: false
- Date Issued: 2011-11
- Authors: Siziba, L P , Makwela, N
- Date: 2011-11
- Language: English
- Type: Examination paper
- Identifier: vital:18275 , http://hdl.handle.net/10353/d1011271
- Description: Academic Practice & Reasoning: APR 122F, examination November 2011.
- Full Text: false
- Date Issued: 2011-11
Academic Practice and Reasoning: APR 122F
- Authors: Siziba, L P , Makwela, N
- Date: 2011-02
- Language: English
- Type: Examination paper
- Identifier: vital:18227 , http://hdl.handle.net/10353/d1011218
- Description: Academic Practice and Reasoning: APR 122F, Supplementary examination February 2011.
- Full Text: false
- Date Issued: 2011-02
- Authors: Siziba, L P , Makwela, N
- Date: 2011-02
- Language: English
- Type: Examination paper
- Identifier: vital:18227 , http://hdl.handle.net/10353/d1011218
- Description: Academic Practice and Reasoning: APR 122F, Supplementary examination February 2011.
- Full Text: false
- Date Issued: 2011-02
Accounting 1A: ACC 111 & 111E
- Mnconywa, N, Mtshwelo, L, Lockyear, M
- Authors: Mnconywa, N , Mtshwelo, L , Lockyear, M
- Date: 2011-06
- Subjects: Accounting
- Language: English
- Type: Examination paper
- Identifier: vital:17419 , http://hdl.handle.net/10353/d1009788
- Description: Accounting 1A: ACC 111 & 111E, examination June 2011.
- Full Text: false
- Date Issued: 2011-06
- Authors: Mnconywa, N , Mtshwelo, L , Lockyear, M
- Date: 2011-06
- Subjects: Accounting
- Language: English
- Type: Examination paper
- Identifier: vital:17419 , http://hdl.handle.net/10353/d1009788
- Description: Accounting 1A: ACC 111 & 111E, examination June 2011.
- Full Text: false
- Date Issued: 2011-06
Address at the opening of the OutRhodes Pride Week, 21 August 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7652 , http://hdl.handle.net/10962/d1015780
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7652 , http://hdl.handle.net/10962/d1015780
- Full Text:
- Date Issued: 2007
Adult African sharptooth catfish, Clarias gariepinus, population dynamics in a small invaded warm-temperate impoundment
- Booth, Anthony J, Traas, Graham R L, Weyl, Olaf L F
- Authors: Booth, Anthony J , Traas, Graham R L , Weyl, Olaf L F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123596 , vital:35461 , https://doi.10.3377/004.045.0208
- Description: African sharptooth catfish, Clarias gariepinus (Burchell 1822), is a potamodromous species that is naturally distributed from Turkey to the Orange River, South Africa (Skelton 1993). It is omnivorous, feeding on plankton, vegetation, invertebrates, carrion and fish (de Moor & Bruton 1988) and may exhibit pack-hunting behaviour when foraging for small fish (Bruton 1979; Merron 1993). Clarias gariepinus is a large (>150 cm TL, >30 kg; Bruton 1976), long-lived (validated to at least 15 years, Weyl & Booth 2008) and fast-growing (Bruton & Allanson 1980; Quick & Bruton 1984; Richardson et al. 2009) fish that attains sexual maturity within two years of age (de Moor & Bruton 1988). It is eurythermic (80–35°C), mesohalic (0–10 ppt) and has the ability to airbreathe. These attributes predispose it to surviving in all but the most adverse of conditions and have directly contributed to its wide use as an aquaculture species. These attributes have also contributed to its ability to invade waterbodies beyond its natural range (de Moor & Bruton 1988) and after inadvertent introductions such as by escape from aquaculture facilities or through water transfer schemes, C. gariepinus has established populations in many non-native environments. Such invasions include the Philippines (Mercene 1997), Bangladesh (Arthur & Ahmed 2002), Thailand (Vidthayanon 2005), India (Bhakta & Bandyopadhyay 2007) and Brazil (Cambray 2005; Vitule et al. 2006; Rocha & Schiavetti 2007). In South Africa, C. gariepinus invaded the temperate Great Fish River catchment after the species was translocated from the Orange River through a Interbasin Water Transfer (IBWT) scheme (Laurenson et al. 1989). Potential threats include predation of and competition with indigenous species, habitat degradation, and the spread of diseases and parasites (Dudgeon et al. 2006).
- Full Text:
- Date Issued: 2010
- Authors: Booth, Anthony J , Traas, Graham R L , Weyl, Olaf L F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123596 , vital:35461 , https://doi.10.3377/004.045.0208
- Description: African sharptooth catfish, Clarias gariepinus (Burchell 1822), is a potamodromous species that is naturally distributed from Turkey to the Orange River, South Africa (Skelton 1993). It is omnivorous, feeding on plankton, vegetation, invertebrates, carrion and fish (de Moor & Bruton 1988) and may exhibit pack-hunting behaviour when foraging for small fish (Bruton 1979; Merron 1993). Clarias gariepinus is a large (>150 cm TL, >30 kg; Bruton 1976), long-lived (validated to at least 15 years, Weyl & Booth 2008) and fast-growing (Bruton & Allanson 1980; Quick & Bruton 1984; Richardson et al. 2009) fish that attains sexual maturity within two years of age (de Moor & Bruton 1988). It is eurythermic (80–35°C), mesohalic (0–10 ppt) and has the ability to airbreathe. These attributes predispose it to surviving in all but the most adverse of conditions and have directly contributed to its wide use as an aquaculture species. These attributes have also contributed to its ability to invade waterbodies beyond its natural range (de Moor & Bruton 1988) and after inadvertent introductions such as by escape from aquaculture facilities or through water transfer schemes, C. gariepinus has established populations in many non-native environments. Such invasions include the Philippines (Mercene 1997), Bangladesh (Arthur & Ahmed 2002), Thailand (Vidthayanon 2005), India (Bhakta & Bandyopadhyay 2007) and Brazil (Cambray 2005; Vitule et al. 2006; Rocha & Schiavetti 2007). In South Africa, C. gariepinus invaded the temperate Great Fish River catchment after the species was translocated from the Orange River through a Interbasin Water Transfer (IBWT) scheme (Laurenson et al. 1989). Potential threats include predation of and competition with indigenous species, habitat degradation, and the spread of diseases and parasites (Dudgeon et al. 2006).
- Full Text:
- Date Issued: 2010