Cultivating a scholarly community of practice
- Lotz-Sisitka, Heila, Ellery, Karen, Olvitt, Lausanne L, Schudel, Ingrid J, O'Donoghue, Rob
- Authors: Lotz-Sisitka, Heila , Ellery, Karen , Olvitt, Lausanne L , Schudel, Ingrid J , O'Donoghue, Rob
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69777 , vital:29579 , https://hdl.handle.net/10520/EJC15102
- Description: In the field of Environment and Sustainability Education we are seeking ways of developing our teaching and supervision practices to enable social changes in a rapidly transforming field of practice where global issues of truth, judgement, justice and sustainability define our engagements with the public good. This article explores the process of cultivating a scholarly community of practice as a model of supervision that not only engages scholars in an intellectual community oriented towards socio-ecological transformation, but also extends and enhances dialogue with individuals on the technical and theoretical aspects of their postgraduate studies.
- Full Text: false
- Date Issued: 2010
- Authors: Lotz-Sisitka, Heila , Ellery, Karen , Olvitt, Lausanne L , Schudel, Ingrid J , O'Donoghue, Rob
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69777 , vital:29579 , https://hdl.handle.net/10520/EJC15102
- Description: In the field of Environment and Sustainability Education we are seeking ways of developing our teaching and supervision practices to enable social changes in a rapidly transforming field of practice where global issues of truth, judgement, justice and sustainability define our engagements with the public good. This article explores the process of cultivating a scholarly community of practice as a model of supervision that not only engages scholars in an intellectual community oriented towards socio-ecological transformation, but also extends and enhances dialogue with individuals on the technical and theoretical aspects of their postgraduate studies.
- Full Text: false
- Date Issued: 2010
Ethics-oriented learning in environmental education workplaces: An activity theory approach
- Authors: Olvitt, Lausanne L
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370961 , vital:66398 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122874"
- Description: In the context of increasing national and global environmental challenges and their implications for the working world, new ethics and practices are being introduced into workplaces that take better account of socio-ecological relations. Little is understood, however, about the nature of ethics-oriented workplace learning. Drawing on Cultural Historical Activity Theory (CHAT), which enables historically and contextually situated relational perspectives to emerge, this paper explores contradictions in the activity systems of two young environmental education learner-practitioners struggling to engage with the ethical dimensions of their professional work and the professional development course they are studying. The study focuses in particular on the environmental values and ethics component of their course – a year-long Learnership in Environmental Education, Training and Development Practices (EETDP). The paper reflects how tensions and contradictions within and between the interacting activity systems of the workplace, the course, and its regulating qualifications authority influence the teaching and learning of the environmental ethics component of the course. Ethics-oriented teaching and learning processes are found to be strongly influenced by the ‘rules’ and ‘mediating tools’ of these interacting systems, but these are often at odds with the ethical perspectives, socio-cultural context and skills of the ‘subject’ and ‘community’. These systemic contradictions can be more fully understood when their cultural and historical origins are made explicit. The analytical process has led to a more nuanced understanding of ethics-oriented teaching and learning in a workplace-based course, and has revealed several areas needing more careful research (particularly the area of environmental discourses) and the explicit and implicit language of ethics.
- Full Text:
- Date Issued: 2010
- Authors: Olvitt, Lausanne L
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370961 , vital:66398 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122874"
- Description: In the context of increasing national and global environmental challenges and their implications for the working world, new ethics and practices are being introduced into workplaces that take better account of socio-ecological relations. Little is understood, however, about the nature of ethics-oriented workplace learning. Drawing on Cultural Historical Activity Theory (CHAT), which enables historically and contextually situated relational perspectives to emerge, this paper explores contradictions in the activity systems of two young environmental education learner-practitioners struggling to engage with the ethical dimensions of their professional work and the professional development course they are studying. The study focuses in particular on the environmental values and ethics component of their course – a year-long Learnership in Environmental Education, Training and Development Practices (EETDP). The paper reflects how tensions and contradictions within and between the interacting activity systems of the workplace, the course, and its regulating qualifications authority influence the teaching and learning of the environmental ethics component of the course. Ethics-oriented teaching and learning processes are found to be strongly influenced by the ‘rules’ and ‘mediating tools’ of these interacting systems, but these are often at odds with the ethical perspectives, socio-cultural context and skills of the ‘subject’ and ‘community’. These systemic contradictions can be more fully understood when their cultural and historical origins are made explicit. The analytical process has led to a more nuanced understanding of ethics-oriented teaching and learning in a workplace-based course, and has revealed several areas needing more careful research (particularly the area of environmental discourses) and the explicit and implicit language of ethics.
- Full Text:
- Date Issued: 2010
Present day challenges in understanding the geomagnetic hazard to national power grids
- Thompson, A W P, Kotze, P, Ngwira, C M, Lotz, Stefanus I, Gaunt, C T, Cilliers, P, Wild, J A, Opperman, Ben D L, McKinnell, Lee-Anne, Lotz, S I
- Authors: Thompson, A W P , Kotze, P , Ngwira, C M , Lotz, Stefanus I , Gaunt, C T , Cilliers, P , Wild, J A , Opperman, Ben D L , McKinnell, Lee-Anne , Lotz, S I
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6812 , http://hdl.handle.net/10962/d1004305
- Description: Power grids and pipeline networks at all latitudes are known to be at risk from the natural hazard of geomagnetically induced currents. At a recent workshop in South Africa, UK and South African scientists and engineers discussed the current understanding of this hazard, as it affects major power systems in Europe and Africa. They also summarised, to better inform the public and industry, what can be said with some certainty about the hazard and what research is yet required to develop useful tools for geomagnetic hazard mitigation.
- Full Text:
- Date Issued: 2010
- Authors: Thompson, A W P , Kotze, P , Ngwira, C M , Lotz, Stefanus I , Gaunt, C T , Cilliers, P , Wild, J A , Opperman, Ben D L , McKinnell, Lee-Anne , Lotz, S I
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6812 , http://hdl.handle.net/10962/d1004305
- Description: Power grids and pipeline networks at all latitudes are known to be at risk from the natural hazard of geomagnetically induced currents. At a recent workshop in South Africa, UK and South African scientists and engineers discussed the current understanding of this hazard, as it affects major power systems in Europe and Africa. They also summarised, to better inform the public and industry, what can be said with some certainty about the hazard and what research is yet required to develop useful tools for geomagnetic hazard mitigation.
- Full Text:
- Date Issued: 2010
An investigation into what influences action competence-oriented teaching and learning processes in a school environmental club
- Authors: James, Alison
- Date: 2010
- Subjects: Environmental education -- South Africa -- East London Environmental education -- Activity programs -- South Africa -- East London Environmental literacy -- South Africa -- East London Environmental literacy -- Study and teaching -- South Africa -- East London Active learning -- South Africa -- East London Competency-based education -- South Africa -- East London Teacher-student relationships -- South Africa -- East London
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1619 , http://hdl.handle.net/10962/d1003501
- Description: This interpretive case study sought to determine what influenced action competence-oriented teaching and learning processes in a high school environmental club. The goals were to describe a year of activities, within the TALON environmental club at Hudson Park High School in East London, South Africa and to identify how pedagogical, contextual and relational factors influenced action competence processes amongst club members. I explored how action competence theory and praxis have helped in other school education settings with the aim of establishing better environmental practices. The IVAC model of pedagogy (Jensen & Schnack, 1997) was used as a framework to operationalise action competence processes within the TALON Club. This entailed carefully examining investigative, visioning, action and change processes unfolding through the four themes of the club: plants, animal welfare, waste issues and our community outreach programme at Bongulethu High School. Using questionnaires, interviews, observation and a journal as the main methods of data collection I was able to make five analytical statements that related to the influence of pedagogy, the influence of context and the influence of relational dynamics within the TALON Club. The pedagogical processes were affected by the TALON members wanting to avoid any activities that were ‘too much like school’. However this served to compromise the action and visioning phases within the club, resulting in superficial and poorly-informed action-taking. The influence of context served to both enable and constrain action competence processes. The club and school structures therefore shaped the form that fledgling actions took as the TALON members participated in the meetings and outings and fulfilling the traditional expectations of the school community. Relational dynamics and a desire for fun took precedence over the action competence processes. Although the Club members were motivated by a sense of moral responsibility they were unable to articulate this concept into the club activities. In addition there were the power gradients between the educators and members to consider as determinants of the extent of participatory, democratic interactions. This complex interplay of factors influenced the action competence processes in the club. Recommendations were made on how best to work with the concepts of participation and democracy towards improving the reflexivity and knowledge base of both the educators and learners. In this way action competence processes will be better supported within the club in future.
- Full Text:
- Date Issued: 2010
- Authors: James, Alison
- Date: 2010
- Subjects: Environmental education -- South Africa -- East London Environmental education -- Activity programs -- South Africa -- East London Environmental literacy -- South Africa -- East London Environmental literacy -- Study and teaching -- South Africa -- East London Active learning -- South Africa -- East London Competency-based education -- South Africa -- East London Teacher-student relationships -- South Africa -- East London
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1619 , http://hdl.handle.net/10962/d1003501
- Description: This interpretive case study sought to determine what influenced action competence-oriented teaching and learning processes in a high school environmental club. The goals were to describe a year of activities, within the TALON environmental club at Hudson Park High School in East London, South Africa and to identify how pedagogical, contextual and relational factors influenced action competence processes amongst club members. I explored how action competence theory and praxis have helped in other school education settings with the aim of establishing better environmental practices. The IVAC model of pedagogy (Jensen & Schnack, 1997) was used as a framework to operationalise action competence processes within the TALON Club. This entailed carefully examining investigative, visioning, action and change processes unfolding through the four themes of the club: plants, animal welfare, waste issues and our community outreach programme at Bongulethu High School. Using questionnaires, interviews, observation and a journal as the main methods of data collection I was able to make five analytical statements that related to the influence of pedagogy, the influence of context and the influence of relational dynamics within the TALON Club. The pedagogical processes were affected by the TALON members wanting to avoid any activities that were ‘too much like school’. However this served to compromise the action and visioning phases within the club, resulting in superficial and poorly-informed action-taking. The influence of context served to both enable and constrain action competence processes. The club and school structures therefore shaped the form that fledgling actions took as the TALON members participated in the meetings and outings and fulfilling the traditional expectations of the school community. Relational dynamics and a desire for fun took precedence over the action competence processes. Although the Club members were motivated by a sense of moral responsibility they were unable to articulate this concept into the club activities. In addition there were the power gradients between the educators and members to consider as determinants of the extent of participatory, democratic interactions. This complex interplay of factors influenced the action competence processes in the club. Recommendations were made on how best to work with the concepts of participation and democracy towards improving the reflexivity and knowledge base of both the educators and learners. In this way action competence processes will be better supported within the club in future.
- Full Text:
- Date Issued: 2010
Microalgal biomass and distribution in the Mngazi and Mngazana Estuaries
- Ngesi, Hlekani Ntombizakithi
- Authors: Ngesi, Hlekani Ntombizakithi
- Date: 2010
- Subjects: Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10610 , http://hdl.handle.net/10948/1591 , Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Description: The present study was undertaken in the temporarily open/closed Mngazi and permanently open Mngazana estuaries, located on the subtropical east coast of South Africa. The results from this research will assist decision makers in the freshwater management of these systems. Intertidal and subtidal benthic chlorophyll a concentrations, water column chlorophyll a, nutrients and several physico-chemical parameters were measured between June 2002 and November 2003. The objective of this study was to determine if the presence of freshwater in the estuaries had an effect on the microalgae of both estuaries. Five sites were sampled in the Mngazi Estuary and 14 sites were sampled in the Mngazana Estuary. The average water column chlorophyll a was significantly higher (p<0.05) in the Mngazana Estuary (surface 7.8 ± 0.7 μg.l-1, bottom 6.4 ± 0.7 μg.l-1) compared to the Mngazi Estuary (surface 4.9 ± 1.2 μg.l-1, bottom 7.3 ± 1.5 μg.l-1). There was no evidence of an REI (river-estuary interface) zone in areas where the water column chlorophyll a concentrations were high even during open mouth conditions in the Mngazi Estuary. The REI is that area where salinity is less than 10 ppt and is characterized by high water column productivity. Even though both systems received some freshwater during the summer periods, this was not enough to stimulate phytoplankton growth and nutrient availability seems to be the major factor limiting phytoplankton in these systems. Flagellates and diatoms were the dominant phytoplankton groups in both estuaries during the entire sampling session. The relative abundance of the different phytoplankton groups did not show differences between sites. The relative abundance of flagellates was in most cases greater than 60% and diatoms made up the remainder. The average benthic chlorophyll a was higher in the Mngazana Estuary (intertidal 24 ± 6 μg.g-1 subtidal 15.2 ± 3 μg.g-1) compared to the Mngazi Estuary (intertidal 15.3 ± 4.3 μg.g-1 subtidal 5.4 ± 1.6 μg.g-1). Regions with high benthic chlorophyll a concentrations had high sediment organic content. Sediment organic content was higher in the Mngazana Estuary (1 percent - 8 percent) compared to the Mngazi Estuary (4 percent – 6.8 percent). The sites situated on the Main Channel had on average significantly higher (p<0.05) benthic chlorophyll a biomass compared to Creek 1 and Creek 2 in the Mngazana Estuary. Peaks in benthic chlorophyll a concentrations occurred in the intertidal sediments in Creek 1 (50.4 ± 13.4 μg.g-1) and Creek 2 (57.4 ± 1.4 μg.g-1) in the Mngazana Estuary, the peaks occurred in winter during a period of low freshwater inflow into the estuary. Microphytobenthic biomass measured in the Mngazi Estuary is among the lowest values reported in the literature for temporarily open/closed estuaries. Statistical 4 analysis showed no significant difference between benthic chlorophyll a during the different mouth conditions and sampling sessions in the Mngazi Estuary. Microalgal responses in the Mngazana Estuary were similar to those observed in other permanently open marine dominated estuaries. In the temporarily open/closed Mngazi Estuary microalgal characteristics were different to that of other temporarily open/closed estuaries probably because the estuary was only sampled in the open and semi-closed state.
- Full Text:
- Date Issued: 2010
- Authors: Ngesi, Hlekani Ntombizakithi
- Date: 2010
- Subjects: Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10610 , http://hdl.handle.net/10948/1591 , Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Description: The present study was undertaken in the temporarily open/closed Mngazi and permanently open Mngazana estuaries, located on the subtropical east coast of South Africa. The results from this research will assist decision makers in the freshwater management of these systems. Intertidal and subtidal benthic chlorophyll a concentrations, water column chlorophyll a, nutrients and several physico-chemical parameters were measured between June 2002 and November 2003. The objective of this study was to determine if the presence of freshwater in the estuaries had an effect on the microalgae of both estuaries. Five sites were sampled in the Mngazi Estuary and 14 sites were sampled in the Mngazana Estuary. The average water column chlorophyll a was significantly higher (p<0.05) in the Mngazana Estuary (surface 7.8 ± 0.7 μg.l-1, bottom 6.4 ± 0.7 μg.l-1) compared to the Mngazi Estuary (surface 4.9 ± 1.2 μg.l-1, bottom 7.3 ± 1.5 μg.l-1). There was no evidence of an REI (river-estuary interface) zone in areas where the water column chlorophyll a concentrations were high even during open mouth conditions in the Mngazi Estuary. The REI is that area where salinity is less than 10 ppt and is characterized by high water column productivity. Even though both systems received some freshwater during the summer periods, this was not enough to stimulate phytoplankton growth and nutrient availability seems to be the major factor limiting phytoplankton in these systems. Flagellates and diatoms were the dominant phytoplankton groups in both estuaries during the entire sampling session. The relative abundance of the different phytoplankton groups did not show differences between sites. The relative abundance of flagellates was in most cases greater than 60% and diatoms made up the remainder. The average benthic chlorophyll a was higher in the Mngazana Estuary (intertidal 24 ± 6 μg.g-1 subtidal 15.2 ± 3 μg.g-1) compared to the Mngazi Estuary (intertidal 15.3 ± 4.3 μg.g-1 subtidal 5.4 ± 1.6 μg.g-1). Regions with high benthic chlorophyll a concentrations had high sediment organic content. Sediment organic content was higher in the Mngazana Estuary (1 percent - 8 percent) compared to the Mngazi Estuary (4 percent – 6.8 percent). The sites situated on the Main Channel had on average significantly higher (p<0.05) benthic chlorophyll a biomass compared to Creek 1 and Creek 2 in the Mngazana Estuary. Peaks in benthic chlorophyll a concentrations occurred in the intertidal sediments in Creek 1 (50.4 ± 13.4 μg.g-1) and Creek 2 (57.4 ± 1.4 μg.g-1) in the Mngazana Estuary, the peaks occurred in winter during a period of low freshwater inflow into the estuary. Microphytobenthic biomass measured in the Mngazi Estuary is among the lowest values reported in the literature for temporarily open/closed estuaries. Statistical 4 analysis showed no significant difference between benthic chlorophyll a during the different mouth conditions and sampling sessions in the Mngazi Estuary. Microalgal responses in the Mngazana Estuary were similar to those observed in other permanently open marine dominated estuaries. In the temporarily open/closed Mngazi Estuary microalgal characteristics were different to that of other temporarily open/closed estuaries probably because the estuary was only sampled in the open and semi-closed state.
- Full Text:
- Date Issued: 2010
Reactivity of Rhenium (iii) and Rhenium (V) with multidentate NN-and no-donor ligands
- Yumata, Nonzaliseko Christine
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010
Comparison of A₄ neutrino mass models
- Barry, James Munnik Hamilton
- Authors: Barry, James Munnik Hamilton
- Date: 2010
- Subjects: Neutrinos -- Mass , Standard model (Nuclear physics) , Particles (Nuclear physics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5554 , http://hdl.handle.net/10962/d1015271
- Description: The present neutrino oscillation data are compatible with tri-bimaximal mixing, to leading order. The addition of an A₄ family symmetry and extended Higgs sector to the Standard Model can generate this mixing pattern, assuming the correct vacuum expectation value alignment of Higgs scalars. The effect of deviating this alignment is studied, for different types of A₄ models, with a phenomenological emphasis: the effect of perturbations on the model predictions for the neutrino oscillation and neutrino mass observables. The standard theoretical description of neutrino oscillations is presented, along with a summary of the past, present and future experimental efforts aimed at measuring the neutrino mixing parameters. Additionally, the current constraints on the sum of absolute neutrino masses and the amplitude for neutrinoless double beta decay, which is yet to be observed, are discussed. These constraints provide a model-independent test of family symmetery models. The Standard Model is reviewed, and extensions to the Standard Model such as the seesaw mechanism(s) are discussed: these are designed to endow neutrinos with mass, and can be incorporated into A₄ symmetry models. Models with different A₄ particle assignments are analysed for deviations from tribimaximal mixing. There are nine models presented in Chapter 5, with lepton doublets transforming as 3 (underlined) and right-handed charged leptons transforming as 1, 1', 1" (all underlined) ; five of these include right-handed neutrinos transforming as 3 (underlined) and make use of the seesaw mechanism. Chapter 6 contains the analysis of six models that assign all leptons to the 3 (underlined) representation, with four of these utilising the seesaw mechanism. The models are tested for any degree of fine tuning of the parameters that define the mass matrices. The effect of perturbations on the mixing angle observables, in particular sin² ∅₁₃ and sin² ∅₂₃, is studied, as well as the effect on the Jarlskog invariant, Jcp. Investigations of the (Mee)- ∑Mv parameter space allow for comparison with current data, and can lead to the possible exclusion of a particular model by constraints from future data.
- Full Text:
- Date Issued: 2010
- Authors: Barry, James Munnik Hamilton
- Date: 2010
- Subjects: Neutrinos -- Mass , Standard model (Nuclear physics) , Particles (Nuclear physics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5554 , http://hdl.handle.net/10962/d1015271
- Description: The present neutrino oscillation data are compatible with tri-bimaximal mixing, to leading order. The addition of an A₄ family symmetry and extended Higgs sector to the Standard Model can generate this mixing pattern, assuming the correct vacuum expectation value alignment of Higgs scalars. The effect of deviating this alignment is studied, for different types of A₄ models, with a phenomenological emphasis: the effect of perturbations on the model predictions for the neutrino oscillation and neutrino mass observables. The standard theoretical description of neutrino oscillations is presented, along with a summary of the past, present and future experimental efforts aimed at measuring the neutrino mixing parameters. Additionally, the current constraints on the sum of absolute neutrino masses and the amplitude for neutrinoless double beta decay, which is yet to be observed, are discussed. These constraints provide a model-independent test of family symmetery models. The Standard Model is reviewed, and extensions to the Standard Model such as the seesaw mechanism(s) are discussed: these are designed to endow neutrinos with mass, and can be incorporated into A₄ symmetry models. Models with different A₄ particle assignments are analysed for deviations from tribimaximal mixing. There are nine models presented in Chapter 5, with lepton doublets transforming as 3 (underlined) and right-handed charged leptons transforming as 1, 1', 1" (all underlined) ; five of these include right-handed neutrinos transforming as 3 (underlined) and make use of the seesaw mechanism. Chapter 6 contains the analysis of six models that assign all leptons to the 3 (underlined) representation, with four of these utilising the seesaw mechanism. The models are tested for any degree of fine tuning of the parameters that define the mass matrices. The effect of perturbations on the mixing angle observables, in particular sin² ∅₁₃ and sin² ∅₂₃, is studied, as well as the effect on the Jarlskog invariant, Jcp. Investigations of the (Mee)- ∑Mv parameter space allow for comparison with current data, and can lead to the possible exclusion of a particular model by constraints from future data.
- Full Text:
- Date Issued: 2010
The impact of the Western conceptualization of the Christian gospel on its communication in a non-Western environment, with particular reference to the AmaXhosa
- Authors: Higgs, Michael John
- Date: 2010
- Subjects: Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Language: English
- Type: Thesis , Doctoral , D Th
- Identifier: vital:11800 , http://hdl.handle.net/10353/356 , Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Description: This thesis examines the extent and nature of the impact of the contextualization of Christianity upon the amaXhosa from the missionary irruption in the nineteenth century to the present day, and proceeds to examine the implications of this impact for the presentation of the Christian gospel in the contemporary Eastern Cape. Chapter One describes the problem, offers definitions of key concepts and outlines the procedural method for the rest of the thesis. Chapter Two deals with the question of the cross-cultural communication of the Christian gospel in theory. Doctrinal questions such as the nature of the gospel are examined. The basic hermeneutical issue of the categorization of doctrinal tenets according to whether they are required or simply permitted is discussed in terms of Osborne's categories: 'cardinal', 'non-cardinal'. Tenets which are found to be 'anti-scriptural' would be rejected. Specific hermeneutical topics such as language and meaning, symbolics, textuality and orality are then discussed. This is followed by a survey of secular influences which affect a conceptualization. This chapter is preparatory to, and definitive for, the discourse which follows. Chapter Three outlines the cultural heritage from which the Western missionary contextualization of Christianity developed. It shows the extent to which this presentation of the gospel was dependent upon the philosophy which Britain and Europe inherited from the classical Greek culture. More modern developments such as the Enlightenment, Empiricism and Historicism bring the discourse up to the point at which the missionaries arrived. Chapter Four deals with the initial encounter between the missionaries and the amaXhosa. A brief account is given of the nature of the religious and spiritual aspects of the Xhosa culture which first encountered Christianity. The doctrinal section of this chapter deals with those doctrines in the missionary message which became issues for the amaXhosa. The hermeneutical section shows how the cultural setting of the West (vii) affected both the contextualization by the missionaries and the conceptualization by the amaXhosa. To a large extent, the missionaries made the double mistake of imposing their culture on the amaXhosa and failing to accord respect, even recognition, to the Xhosa culture. This amounted to imperialism, which, together with the political imperialism of Britain as the colonizing power, evoked responses from the Xhosa community which are outlined in section 4.4, including those of Nxele and Ntsikana. Because the impact of the Western contextualization is an on-going phenomenon, the thesis continues to trace its development up to the present time. Apartheid is briefly mentioned in Chapter Five. The point is made that all white people were perceived by the amaXhosa to be Christians, and the architects and practitioners of apartheid claimed to be Christians. This ideology therefore had a direct effect on the Xhosa conceptualization of the gospel. The architects of apartheid actually believed that they were accepting God's gift and mandate. This chapter includes Black theological reaction to apartheid in terms of the South African version of Liberation theology. Chapter Six returns to Western Theology in order to bring the sphere of discourse from the point at which it left off at the end of Chapter Three up to the present time. The schools of thought in this period are: Secularism and Existentialism, together with their theological extension, Demythologization. The main religious movements are the Charismatic Movement and Neo-Pentecostalism. Postmodernism came as a later philosophical school, to be followed by Globality. Chapter Seven deals with black South African reactive and proactive responses. The predominant theologies are those of Dwane, Buthelezi, Boesak and Mtuze. Although Dwane, Buthelezi and Boesak came on the scene at the same time as the black theologians reviewed in Chapter Five, their work is placed here because it differs significantly from the more radical responses of the latter. Mtuze is post-apartheid, and responds to the developments outlined in Chapter Six. Chapter Eight draws the findings of the thesis together, by considering how the Christian Gospel ought to be presented to the various contemporary sub-cultures of the amaXhosa. (viii) The last Chapter applies the findings of the thesis to the task in hand. The desired outcomes are listed and briefly discussed. The task ahead is enunciated in terms of manpower and other resources for the effective communication of the Christian gospel in the twenty-first century. The past, present and projected programmes of the Bible Institute Eastern Cape [the target institution] are described and assessed. Finally, topics which presented themselves in the course of the preparation of this thesis are suggested for future research.
- Full Text:
- Date Issued: 2010
- Authors: Higgs, Michael John
- Date: 2010
- Subjects: Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Language: English
- Type: Thesis , Doctoral , D Th
- Identifier: vital:11800 , http://hdl.handle.net/10353/356 , Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Description: This thesis examines the extent and nature of the impact of the contextualization of Christianity upon the amaXhosa from the missionary irruption in the nineteenth century to the present day, and proceeds to examine the implications of this impact for the presentation of the Christian gospel in the contemporary Eastern Cape. Chapter One describes the problem, offers definitions of key concepts and outlines the procedural method for the rest of the thesis. Chapter Two deals with the question of the cross-cultural communication of the Christian gospel in theory. Doctrinal questions such as the nature of the gospel are examined. The basic hermeneutical issue of the categorization of doctrinal tenets according to whether they are required or simply permitted is discussed in terms of Osborne's categories: 'cardinal', 'non-cardinal'. Tenets which are found to be 'anti-scriptural' would be rejected. Specific hermeneutical topics such as language and meaning, symbolics, textuality and orality are then discussed. This is followed by a survey of secular influences which affect a conceptualization. This chapter is preparatory to, and definitive for, the discourse which follows. Chapter Three outlines the cultural heritage from which the Western missionary contextualization of Christianity developed. It shows the extent to which this presentation of the gospel was dependent upon the philosophy which Britain and Europe inherited from the classical Greek culture. More modern developments such as the Enlightenment, Empiricism and Historicism bring the discourse up to the point at which the missionaries arrived. Chapter Four deals with the initial encounter between the missionaries and the amaXhosa. A brief account is given of the nature of the religious and spiritual aspects of the Xhosa culture which first encountered Christianity. The doctrinal section of this chapter deals with those doctrines in the missionary message which became issues for the amaXhosa. The hermeneutical section shows how the cultural setting of the West (vii) affected both the contextualization by the missionaries and the conceptualization by the amaXhosa. To a large extent, the missionaries made the double mistake of imposing their culture on the amaXhosa and failing to accord respect, even recognition, to the Xhosa culture. This amounted to imperialism, which, together with the political imperialism of Britain as the colonizing power, evoked responses from the Xhosa community which are outlined in section 4.4, including those of Nxele and Ntsikana. Because the impact of the Western contextualization is an on-going phenomenon, the thesis continues to trace its development up to the present time. Apartheid is briefly mentioned in Chapter Five. The point is made that all white people were perceived by the amaXhosa to be Christians, and the architects and practitioners of apartheid claimed to be Christians. This ideology therefore had a direct effect on the Xhosa conceptualization of the gospel. The architects of apartheid actually believed that they were accepting God's gift and mandate. This chapter includes Black theological reaction to apartheid in terms of the South African version of Liberation theology. Chapter Six returns to Western Theology in order to bring the sphere of discourse from the point at which it left off at the end of Chapter Three up to the present time. The schools of thought in this period are: Secularism and Existentialism, together with their theological extension, Demythologization. The main religious movements are the Charismatic Movement and Neo-Pentecostalism. Postmodernism came as a later philosophical school, to be followed by Globality. Chapter Seven deals with black South African reactive and proactive responses. The predominant theologies are those of Dwane, Buthelezi, Boesak and Mtuze. Although Dwane, Buthelezi and Boesak came on the scene at the same time as the black theologians reviewed in Chapter Five, their work is placed here because it differs significantly from the more radical responses of the latter. Mtuze is post-apartheid, and responds to the developments outlined in Chapter Six. Chapter Eight draws the findings of the thesis together, by considering how the Christian Gospel ought to be presented to the various contemporary sub-cultures of the amaXhosa. (viii) The last Chapter applies the findings of the thesis to the task in hand. The desired outcomes are listed and briefly discussed. The task ahead is enunciated in terms of manpower and other resources for the effective communication of the Christian gospel in the twenty-first century. The past, present and projected programmes of the Bible Institute Eastern Cape [the target institution] are described and assessed. Finally, topics which presented themselves in the course of the preparation of this thesis are suggested for future research.
- Full Text:
- Date Issued: 2010
Rhodes University Research Report 2010
- Rhodes University, Roberts, Jaine
- Authors: Rhodes University , Roberts, Jaine
- Date: 2010
- Language: English
- Type: Text
- Identifier: vital:565 , http://hdl.handle.net/10962/d1011968
- Description: From Introduction: In 2010, the total subsidy earning accredited research output count for Rhodes University of 615.3 units represents an increase of 9% on the previous year. By far the major contributor to this growth was the significant increase in both PhD (37.5% up on 2009) and Masters by thesis students (34.5% up on 2009). Rhodes contributed 3.3% of all accredited research output in the public higher education sector in 2010 (0.1% up on 2009). With 1.9% of academic staff in the system, Rhodes retained its place amongst the top three most productive universities as measured by accredited publications per academic. Rhodes exceeds the DHET research output norm for universities by 53%. In 2010, the total accredited publication output count for Rhodes University of 325.33 units represented a decline over 2009 of 7.3 percent. This followed two years of steep growth during which accredited research publication output grew by 28%. Accredited publication output for 2010 consisted mainly of journals at 89.9%, with conference proceedings at 7.2% and books and book chapters at 2.9% making far smaller contributions. This mix is roughly in line with the sector as a whole. It has been recognised that books and book chapters are underappreciated in relation to journals, and recommendations to increase the weighted points that they attract as proposed by ASSAf1 are awaiting approval by the DHET. and book chapters submitted, because the hurdle of independent reviewing is not always met by the publishing avenues chosen by authors. The University has become increasingly reliant on research funding in recent years as a larger proportion of its budget, and attention at university council level is being given to ensuring that appropriate systems and support structures for researchers are in place. I add my warm thanks and congratulations to all of our researchers, funders, collaborators and partners who contributed to the excellent research results of 2010. , A Publication of the Rhodes Research Office,compiled and edited by Jaine Roberts
- Full Text:
- Date Issued: 2010
- Authors: Rhodes University , Roberts, Jaine
- Date: 2010
- Language: English
- Type: Text
- Identifier: vital:565 , http://hdl.handle.net/10962/d1011968
- Description: From Introduction: In 2010, the total subsidy earning accredited research output count for Rhodes University of 615.3 units represents an increase of 9% on the previous year. By far the major contributor to this growth was the significant increase in both PhD (37.5% up on 2009) and Masters by thesis students (34.5% up on 2009). Rhodes contributed 3.3% of all accredited research output in the public higher education sector in 2010 (0.1% up on 2009). With 1.9% of academic staff in the system, Rhodes retained its place amongst the top three most productive universities as measured by accredited publications per academic. Rhodes exceeds the DHET research output norm for universities by 53%. In 2010, the total accredited publication output count for Rhodes University of 325.33 units represented a decline over 2009 of 7.3 percent. This followed two years of steep growth during which accredited research publication output grew by 28%. Accredited publication output for 2010 consisted mainly of journals at 89.9%, with conference proceedings at 7.2% and books and book chapters at 2.9% making far smaller contributions. This mix is roughly in line with the sector as a whole. It has been recognised that books and book chapters are underappreciated in relation to journals, and recommendations to increase the weighted points that they attract as proposed by ASSAf1 are awaiting approval by the DHET. and book chapters submitted, because the hurdle of independent reviewing is not always met by the publishing avenues chosen by authors. The University has become increasingly reliant on research funding in recent years as a larger proportion of its budget, and attention at university council level is being given to ensuring that appropriate systems and support structures for researchers are in place. I add my warm thanks and congratulations to all of our researchers, funders, collaborators and partners who contributed to the excellent research results of 2010. , A Publication of the Rhodes Research Office,compiled and edited by Jaine Roberts
- Full Text:
- Date Issued: 2010
Metabolic energy relations in the Eastern Cape Angulate Tortoise (Chersina Anguluta)
- Authors: Setlalekgomo, Mpho Rinah
- Date: 2010
- Subjects: Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10690 , http://hdl.handle.net/10948/1400 , Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Description: The daily oxygen consumption (VO2) pattern, the effects of varying ambient temperatures, season and mass on the resting oxygen consumption (RVO2) of Chersina angulata of the Eastern Cape were investigated. The RVO2 was measured using flow-through respirometry and specific resting oxygen consumption (sRVO2) calculated. To determine the daily pattern in the VO2 of C. angulata, the tortoises were acclimated in an environmentally controlled room (ECR) to an ambient temperature of 26 ± 1°C and a light regime of 14 hours of light and 10 hours of darkness (14L:10D) for at least a week prior to the RVO2 measurements. The RVO2 was measured at a constant temperature of 26 ± 1°C, and at three different light regimes, namely: 14L:10D, constant darkness (DD) and constant light (LL). There were no significant effects of mass or gender on the sRVO2 of the tortoises used. Rhythms in the sRVO2 were detected under all three light regimes. The amplitudes of the rhythm were largest at 14L:10D, followed by DD and smallest at LL regime. The persistence of the rhythmic pattern under constant conditions suggests the existence of an endogenous circadian rhythm in the sRVO2 for adult C. angulata. To test for the effect of ambient temperature on the sRVO2 of adult C. angulata, the tortoises were acclimated to 22 ± 1°C and a 14L:10D light regime prior to the RVO2 measurements. RVO2 was measured at eight experimental temperatures; 14°C, 18°C, 22°C, 26°C, 30°C, 35°C, 38°C and 40°C. The sRVO2 was not influenced by gender and increased with experimental temperatures, but this did not happen consistently over the whole range of temperatures tested. A plateau, possibly a thermal preferendum zone, was detected within the temperature range of 26 - 38°C. Determination of seasonal effect on the sRVO2 of adult C. angulata was accomplished by acclimating tortoises to standard summer and winter conditions. Seasonal effects were tested in the appropriate seasons. Winter experiments were conducted in winter and summer experiments conducted in summer. The RVO2 was measured at experimental temperature 14°C, 18°C and 22°C. In addition RVO2 of iv winter-acclimated tortoises was also measured at 10°C. The sRVO2 increased significantly with increasing temperature within the temperature range tested. No distinct pattern was observed in the seasonal acclimation of adult C. angulata. The metabolic rate-temperature curves of the summer and the winter-acclimated tortoises cross each other. Season and temperature had no significant effects on the mass-scaling exponent of the sRVO2. The exponent ranged from 0.48 to 0.73 within the temperature range of 22 - 38°C. Below and above this temperature range, the exponent ranged from 1.47 to 1.67. An inverse relationship was observed between sRVO2 and body mass over the temperature range of 22 - 38°C. At 14°C and 18°C, sRVO2 increased with body mass, while at 10°C and at 40°C the slope was 1.01.
- Full Text:
- Date Issued: 2010
- Authors: Setlalekgomo, Mpho Rinah
- Date: 2010
- Subjects: Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10690 , http://hdl.handle.net/10948/1400 , Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Description: The daily oxygen consumption (VO2) pattern, the effects of varying ambient temperatures, season and mass on the resting oxygen consumption (RVO2) of Chersina angulata of the Eastern Cape were investigated. The RVO2 was measured using flow-through respirometry and specific resting oxygen consumption (sRVO2) calculated. To determine the daily pattern in the VO2 of C. angulata, the tortoises were acclimated in an environmentally controlled room (ECR) to an ambient temperature of 26 ± 1°C and a light regime of 14 hours of light and 10 hours of darkness (14L:10D) for at least a week prior to the RVO2 measurements. The RVO2 was measured at a constant temperature of 26 ± 1°C, and at three different light regimes, namely: 14L:10D, constant darkness (DD) and constant light (LL). There were no significant effects of mass or gender on the sRVO2 of the tortoises used. Rhythms in the sRVO2 were detected under all three light regimes. The amplitudes of the rhythm were largest at 14L:10D, followed by DD and smallest at LL regime. The persistence of the rhythmic pattern under constant conditions suggests the existence of an endogenous circadian rhythm in the sRVO2 for adult C. angulata. To test for the effect of ambient temperature on the sRVO2 of adult C. angulata, the tortoises were acclimated to 22 ± 1°C and a 14L:10D light regime prior to the RVO2 measurements. RVO2 was measured at eight experimental temperatures; 14°C, 18°C, 22°C, 26°C, 30°C, 35°C, 38°C and 40°C. The sRVO2 was not influenced by gender and increased with experimental temperatures, but this did not happen consistently over the whole range of temperatures tested. A plateau, possibly a thermal preferendum zone, was detected within the temperature range of 26 - 38°C. Determination of seasonal effect on the sRVO2 of adult C. angulata was accomplished by acclimating tortoises to standard summer and winter conditions. Seasonal effects were tested in the appropriate seasons. Winter experiments were conducted in winter and summer experiments conducted in summer. The RVO2 was measured at experimental temperature 14°C, 18°C and 22°C. In addition RVO2 of iv winter-acclimated tortoises was also measured at 10°C. The sRVO2 increased significantly with increasing temperature within the temperature range tested. No distinct pattern was observed in the seasonal acclimation of adult C. angulata. The metabolic rate-temperature curves of the summer and the winter-acclimated tortoises cross each other. Season and temperature had no significant effects on the mass-scaling exponent of the sRVO2. The exponent ranged from 0.48 to 0.73 within the temperature range of 22 - 38°C. Below and above this temperature range, the exponent ranged from 1.47 to 1.67. An inverse relationship was observed between sRVO2 and body mass over the temperature range of 22 - 38°C. At 14°C and 18°C, sRVO2 increased with body mass, while at 10°C and at 40°C the slope was 1.01.
- Full Text:
- Date Issued: 2010
Compactification of lattice-valued convergence spaces
- Authors: Jäger, Gunter
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6828 , http://hdl.handle.net/10962/d1012339
- Description: We define compactness for stratified lattice-valued convergence spaces and show that a Tychonoff theorem is true. Further a generalization of the classical Richardson compactification is given. This compactification has a universal property.
- Full Text:
- Date Issued: 2010
- Authors: Jäger, Gunter
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6828 , http://hdl.handle.net/10962/d1012339
- Description: We define compactness for stratified lattice-valued convergence spaces and show that a Tychonoff theorem is true. Further a generalization of the classical Richardson compactification is given. This compactification has a universal property.
- Full Text:
- Date Issued: 2010
Copreneurships in South African small and medium-sized family business
- Authors: Eybers, Carey
- Date: 2010
- Subjects: Couple-owned business enterprises , Family-owned business enterprises -- Succession -- South Africa , Entrepreneurship -- South Africa , Small business -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9285 , http://hdl.handle.net/10948/1207 , Couple-owned business enterprises , Family-owned business enterprises -- Succession -- South Africa , Entrepreneurship -- South Africa , Small business -- South Africa
- Description: Taking cognisance of the increasingly important role that copreneurial businesses play in national economies, the unique challenges that they face, and the lack of research attention given to such spousal teams, the purpose of this study was to contribute to the more effective functioning of copreneurships in South Africa by identifying the factors that impact on their success. Consequently, the primary objective of this study was to investigate the factors that influence the Perceived success of copreneurships in South Africa, as well as the conditions required for the effective and harmonious functioning of such spousal partnerships. This study seeks to incorporate previous findings and studies on team effectiveness and spousal relationships into a comprehensive conceptual model. After conducting a comprehensive literature study, as well as examining the different teamwork models proposed and the study by Farrington (2009), it became clear that successful teams have validated their proficiency with regard to two types of factors, namely, relational-based and organisational-based factors. Within these two categories of factors, 14 independent variables were identified and hypothesised to influence the measures of effectiveness of copreneurships, namely the dependent variable Perceived success; and the intervening variable Financial performance. All of the factors in this study were clearly defined and operationalised. Reliable and valid items sourced from Farrington’s (2009) measuring instrument, as well as several measuring instruments used in other studies, were used in the operationalisation of these factors. In addition, several items were self-generated from secondary sources. Respondents were identified using the convenience snowball sampling technique, and a structured questionnaire was made available to them. The data gathered from the 380 usable questionnaires was subjected to various statistical analyses. The validity and reliability of the measuring instrument was confirmed by means of an exploratory factor analysis, and Cronbach-alpha coefficients were calculated for this purpose. The original intervening variable Financial performance could not be confirmed as originally intended in the conceptual model. Instead, Financial performance split into v two separate variables which were named Financial performance and Growth performance. The original dependent variable Perceived success was confirmed by the factor analyses. The relational- and organisational-based factors could not be confirmed as originally intended in the conceptual model. Instead, seven new relational- and seven new organisational-based factors emerged, and where necessary these factors were renamed. The primary statistical procedure used to test the significance of the relationships hypothesised between the independent and dependent variables in this study, was Structural Equation Modelling (SEM). Owing to the sample-size restrictions, the conceptual model could not be subjected to SEM as a whole. Instead, seven submodels were identified and subjected to further analysis. The following independent variables were identified as influencing the dependent and intervening variables in this study: • Spousal relationship • Commitment to spouse • Equal status • Commitment to the business • Emotional attachment • Non-family involvement • Personal needs alignment • Leadership • Competencies • Internal context In order to investigate the influence of the various demographic variables on the intervening and dependent variables, an Analysis of Variance (ANOVA), Multiple Linear Regression analysis and t-tests were performed. How leadership occurs in a copreneurial business, the tenure of the business, the location of the business, the status of the copreneurship, the level of spousal involvement in the business and the vi number of employees were found to have an influence on the intervening and dependent variables of this study. By empirically investigating copreneurships, this study has added to the limited amount of family business literature on these complex partnerships. By way of the conceptual models developed in this study a significant contribution has been made towards understanding the factors influencing the success of copreneurships. As a result, this study presents recommendations and suggestions to assist couples in managing their copreneurships in such a way as to nurture their marriage relationships and at the same time enhance the performance of their businesses.
- Full Text:
- Date Issued: 2010
- Authors: Eybers, Carey
- Date: 2010
- Subjects: Couple-owned business enterprises , Family-owned business enterprises -- Succession -- South Africa , Entrepreneurship -- South Africa , Small business -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9285 , http://hdl.handle.net/10948/1207 , Couple-owned business enterprises , Family-owned business enterprises -- Succession -- South Africa , Entrepreneurship -- South Africa , Small business -- South Africa
- Description: Taking cognisance of the increasingly important role that copreneurial businesses play in national economies, the unique challenges that they face, and the lack of research attention given to such spousal teams, the purpose of this study was to contribute to the more effective functioning of copreneurships in South Africa by identifying the factors that impact on their success. Consequently, the primary objective of this study was to investigate the factors that influence the Perceived success of copreneurships in South Africa, as well as the conditions required for the effective and harmonious functioning of such spousal partnerships. This study seeks to incorporate previous findings and studies on team effectiveness and spousal relationships into a comprehensive conceptual model. After conducting a comprehensive literature study, as well as examining the different teamwork models proposed and the study by Farrington (2009), it became clear that successful teams have validated their proficiency with regard to two types of factors, namely, relational-based and organisational-based factors. Within these two categories of factors, 14 independent variables were identified and hypothesised to influence the measures of effectiveness of copreneurships, namely the dependent variable Perceived success; and the intervening variable Financial performance. All of the factors in this study were clearly defined and operationalised. Reliable and valid items sourced from Farrington’s (2009) measuring instrument, as well as several measuring instruments used in other studies, were used in the operationalisation of these factors. In addition, several items were self-generated from secondary sources. Respondents were identified using the convenience snowball sampling technique, and a structured questionnaire was made available to them. The data gathered from the 380 usable questionnaires was subjected to various statistical analyses. The validity and reliability of the measuring instrument was confirmed by means of an exploratory factor analysis, and Cronbach-alpha coefficients were calculated for this purpose. The original intervening variable Financial performance could not be confirmed as originally intended in the conceptual model. Instead, Financial performance split into v two separate variables which were named Financial performance and Growth performance. The original dependent variable Perceived success was confirmed by the factor analyses. The relational- and organisational-based factors could not be confirmed as originally intended in the conceptual model. Instead, seven new relational- and seven new organisational-based factors emerged, and where necessary these factors were renamed. The primary statistical procedure used to test the significance of the relationships hypothesised between the independent and dependent variables in this study, was Structural Equation Modelling (SEM). Owing to the sample-size restrictions, the conceptual model could not be subjected to SEM as a whole. Instead, seven submodels were identified and subjected to further analysis. The following independent variables were identified as influencing the dependent and intervening variables in this study: • Spousal relationship • Commitment to spouse • Equal status • Commitment to the business • Emotional attachment • Non-family involvement • Personal needs alignment • Leadership • Competencies • Internal context In order to investigate the influence of the various demographic variables on the intervening and dependent variables, an Analysis of Variance (ANOVA), Multiple Linear Regression analysis and t-tests were performed. How leadership occurs in a copreneurial business, the tenure of the business, the location of the business, the status of the copreneurship, the level of spousal involvement in the business and the vi number of employees were found to have an influence on the intervening and dependent variables of this study. By empirically investigating copreneurships, this study has added to the limited amount of family business literature on these complex partnerships. By way of the conceptual models developed in this study a significant contribution has been made towards understanding the factors influencing the success of copreneurships. As a result, this study presents recommendations and suggestions to assist couples in managing their copreneurships in such a way as to nurture their marriage relationships and at the same time enhance the performance of their businesses.
- Full Text:
- Date Issued: 2010
Molecular and cellular analysis of the interaction between soluble CD23 and CD11/CD18 integrins
- Authors: Daniels, Brodie Belinda
- Date: 2010
- Subjects: CD23 antigen , Immune response -- Regulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10303 , http://hdl.handle.net/10948/1217 , CD23 antigen , Immune response -- Regulation
- Description: The low affinity IgE receptor, CD23, is expressed by a wide variety of cells and cleaved from its original 45 kDa size to several smaller soluble CD23 proteins. Soluble CD23 function depends on the form of the protein and its interaction with various ligands. CD23 is believed to play an important role in regulating allergic responses and in inflammation, amongst others. β2 integrins are important in a variety of cell-adhesion reactions during immune-inflammatory mechanisms and the binding of their natural ligands generates outside-in cellular signalling, leading to cell activation. Although the binding of CD23 to β2 integrins contributes to this signalling in monocytes, the interaction site for CD23 is unknown. This study focused on the interaction of three soluble CD23 proteins with the β2 integrins CD11b/CD18 and CD11c/CD18. Differentiated HL60, THP1 and U937 monocytic cells were used to demonstrate the binding of three recombinant CD23 constructs (corresponding to 16, 25 and 33 kDa human soluble CD23) to upregulated CD11b/CD18 and CD11c/CD18. This binding was partially blocked by an antibody specific for the CD11b/CD18 αI domain, demonstrating that αI domains are involved in binding to CD23. Recombinant αI domain proteins of CD11b and CD11c were demonstrated to bind CD23 using ELISA and in surface plasmon resonance spectroscopy. The dissociation constants for CD23-CD11b/CD18 and CD23-CD11c/CD18 are comparable to other integrin ligands. This study has shown that CD23 interacts directly with the αI domains of β2 integrins and that the interaction surface likely spans the lectin domain as well as either the stalk and/or C-terminal tail of CD23. This study also looked at the effect that soluble CD23 proteins had on monocyte biology. It appears that iv sCD23 proteins have little effect on the phagocytic or chemotactic ability of monocytes, while an increase in oxidative burst was shown with the 16 kDa and 25 kDa CD23 proteins. Signalling pathways for the production of reactive oxygen species were investigated and it appears that the CD23 proteins signal mainly through the phosphoinositide-3 kinase pathway, although the mitogen activated protein kinase and Src kinase pathways may also play a role. These data suggest that sCD23 proteins induce outside-in signalling of β2 integrins and are able to change the activation state of CD11b/CD11c by stimulating oxidative burst. This needs to be further investigated by determining how the three sCD23 proteins are binding the CD11 proteins and investigating further leukocyte function and inflammatory responses by the cells.
- Full Text:
- Date Issued: 2010
- Authors: Daniels, Brodie Belinda
- Date: 2010
- Subjects: CD23 antigen , Immune response -- Regulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10303 , http://hdl.handle.net/10948/1217 , CD23 antigen , Immune response -- Regulation
- Description: The low affinity IgE receptor, CD23, is expressed by a wide variety of cells and cleaved from its original 45 kDa size to several smaller soluble CD23 proteins. Soluble CD23 function depends on the form of the protein and its interaction with various ligands. CD23 is believed to play an important role in regulating allergic responses and in inflammation, amongst others. β2 integrins are important in a variety of cell-adhesion reactions during immune-inflammatory mechanisms and the binding of their natural ligands generates outside-in cellular signalling, leading to cell activation. Although the binding of CD23 to β2 integrins contributes to this signalling in monocytes, the interaction site for CD23 is unknown. This study focused on the interaction of three soluble CD23 proteins with the β2 integrins CD11b/CD18 and CD11c/CD18. Differentiated HL60, THP1 and U937 monocytic cells were used to demonstrate the binding of three recombinant CD23 constructs (corresponding to 16, 25 and 33 kDa human soluble CD23) to upregulated CD11b/CD18 and CD11c/CD18. This binding was partially blocked by an antibody specific for the CD11b/CD18 αI domain, demonstrating that αI domains are involved in binding to CD23. Recombinant αI domain proteins of CD11b and CD11c were demonstrated to bind CD23 using ELISA and in surface plasmon resonance spectroscopy. The dissociation constants for CD23-CD11b/CD18 and CD23-CD11c/CD18 are comparable to other integrin ligands. This study has shown that CD23 interacts directly with the αI domains of β2 integrins and that the interaction surface likely spans the lectin domain as well as either the stalk and/or C-terminal tail of CD23. This study also looked at the effect that soluble CD23 proteins had on monocyte biology. It appears that iv sCD23 proteins have little effect on the phagocytic or chemotactic ability of monocytes, while an increase in oxidative burst was shown with the 16 kDa and 25 kDa CD23 proteins. Signalling pathways for the production of reactive oxygen species were investigated and it appears that the CD23 proteins signal mainly through the phosphoinositide-3 kinase pathway, although the mitogen activated protein kinase and Src kinase pathways may also play a role. These data suggest that sCD23 proteins induce outside-in signalling of β2 integrins and are able to change the activation state of CD11b/CD11c by stimulating oxidative burst. This needs to be further investigated by determining how the three sCD23 proteins are binding the CD11 proteins and investigating further leukocyte function and inflammatory responses by the cells.
- Full Text:
- Date Issued: 2010
Development of a stability-indicating high performance liquid chromatographic method for the analysis of topiramate and dissolution rate testing in topiramate tablets
- Mohammadi, Ali, Rezanour, Nasrin, Ansari Dogaheh, M, Walker, Roderick B
- Authors: Mohammadi, Ali , Rezanour, Nasrin , Ansari Dogaheh, M , Walker, Roderick B
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6412 , http://hdl.handle.net/10962/d1006507
- Description: A stability-indicating high performance liquid chromatographic(HPLC) method was developed and validated for the quantitation and dissolution determination of topiramate in tablet dosage forms. An isocratic separation was achieved using a phenyl column with a flow rate of 1 mL/min using UV detection at 264 nm. Topiramate has low UV absorbtivity and was subjected to derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). The mobile phase for the separation consisted of acetonitrile: 50 mM sodium dihydrogen phosphate(NaH2PO4) containing 3 % v/v triethylamine (pH 2.8) in a 48:52 v/v ratio. Topiramate was subjected to oxidation, hydrolysis, photolysis and heat for the purposes of stress testing. Separation was achieved for the parent compound and all the degradation products in an overall analytical run time of approximately 15 min with the parent compound topiramate eluting at approximately 9.2 min. The method was linear over the concentration range of 1-100 μg/mL (r = 0.9996) with limits of quantitation and detection of 1 and 0.3 μg/mL, respectively.
- Full Text:
- Date Issued: 2010
- Authors: Mohammadi, Ali , Rezanour, Nasrin , Ansari Dogaheh, M , Walker, Roderick B
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6412 , http://hdl.handle.net/10962/d1006507
- Description: A stability-indicating high performance liquid chromatographic(HPLC) method was developed and validated for the quantitation and dissolution determination of topiramate in tablet dosage forms. An isocratic separation was achieved using a phenyl column with a flow rate of 1 mL/min using UV detection at 264 nm. Topiramate has low UV absorbtivity and was subjected to derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). The mobile phase for the separation consisted of acetonitrile: 50 mM sodium dihydrogen phosphate(NaH2PO4) containing 3 % v/v triethylamine (pH 2.8) in a 48:52 v/v ratio. Topiramate was subjected to oxidation, hydrolysis, photolysis and heat for the purposes of stress testing. Separation was achieved for the parent compound and all the degradation products in an overall analytical run time of approximately 15 min with the parent compound topiramate eluting at approximately 9.2 min. The method was linear over the concentration range of 1-100 μg/mL (r = 0.9996) with limits of quantitation and detection of 1 and 0.3 μg/mL, respectively.
- Full Text:
- Date Issued: 2010
Studies towards the development of novel HIV-1 integrase inhibitors
- Authors: Lee, Yi-Chen
- Date: 2010
- Subjects: HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4357 , http://hdl.handle.net/10962/d1005022 , HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Description: The project has focused on the preparation of several series of compounds designed as potential HIV-1 integrase inhibitors. Various 2-nitrobenzaldehydes have been reacted with two activated alkenes, methyl vinyl ketone (MVK) and methyl acrylate, under Baylis-Hillman conditions to afford α-methylene-β-hydroxylalkyl derivatives in moderate to excellent yields. The reactions were conducted using the tertiary amine catalysts, 1,4-diazabicyclo[2.2.2]octane(DABCO) or 3-hydroxyquinuclidine (3-HQ) with chloroform as solvent, and yields were optimised by varying the catalyst, reagent concentrations and the reaction time. Reductive cyclization of the Baylis-Hillman adducts via catalytic hydrogenation, using 10% palladiumon-carbon catalyst in ethanol, afforded quinoline and quinoline N-oxide derivatives. In some cases “acyclic” reduction products were also isolated. Reaction of the Baylis-Hillman MVK adducts with HCl, has resulted in effective nucleophilic (SN’) displacement of the hydroxyl group to afford allylic chloride derivatives. Direct substitution of these chloro derivatives by secondary or primary amines, followed by catalytic hydrogenation gave quinoline derivatives containing a 3-aminomethyl substituent. The Baylis-Hillman ester adducts obtained from reaction with methyl acrylate were treated directly with various amines to give diastereomeric conjugate addition products. Reactions with piperazine gave N,N’-disubstituted piperazine products. The piperidine derivatives have been dehydrated to give cinnamate esters in moderate yields. The products, which have all been satisfactorily characterised by elemental (HRMS) and spectroscopic (1- and 2-D NMR) analysis, constitute a “library” of compounds for in silico and in vitro studies as potential HIV integrase inhibitors.
- Full Text:
- Date Issued: 2010
- Authors: Lee, Yi-Chen
- Date: 2010
- Subjects: HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4357 , http://hdl.handle.net/10962/d1005022 , HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Description: The project has focused on the preparation of several series of compounds designed as potential HIV-1 integrase inhibitors. Various 2-nitrobenzaldehydes have been reacted with two activated alkenes, methyl vinyl ketone (MVK) and methyl acrylate, under Baylis-Hillman conditions to afford α-methylene-β-hydroxylalkyl derivatives in moderate to excellent yields. The reactions were conducted using the tertiary amine catalysts, 1,4-diazabicyclo[2.2.2]octane(DABCO) or 3-hydroxyquinuclidine (3-HQ) with chloroform as solvent, and yields were optimised by varying the catalyst, reagent concentrations and the reaction time. Reductive cyclization of the Baylis-Hillman adducts via catalytic hydrogenation, using 10% palladiumon-carbon catalyst in ethanol, afforded quinoline and quinoline N-oxide derivatives. In some cases “acyclic” reduction products were also isolated. Reaction of the Baylis-Hillman MVK adducts with HCl, has resulted in effective nucleophilic (SN’) displacement of the hydroxyl group to afford allylic chloride derivatives. Direct substitution of these chloro derivatives by secondary or primary amines, followed by catalytic hydrogenation gave quinoline derivatives containing a 3-aminomethyl substituent. The Baylis-Hillman ester adducts obtained from reaction with methyl acrylate were treated directly with various amines to give diastereomeric conjugate addition products. Reactions with piperazine gave N,N’-disubstituted piperazine products. The piperidine derivatives have been dehydrated to give cinnamate esters in moderate yields. The products, which have all been satisfactorily characterised by elemental (HRMS) and spectroscopic (1- and 2-D NMR) analysis, constitute a “library” of compounds for in silico and in vitro studies as potential HIV integrase inhibitors.
- Full Text:
- Date Issued: 2010
Influence of mite predation on the efficacy of the gall midge Dasineura sp. as a biocontrol agent of Australian myrtle Leptospermum laevigatum (Myrtaceae) in South Africa
- Mdlangu, Thabisa Lynette Honey
- Authors: Mdlangu, Thabisa Lynette Honey
- Date: 2010
- Subjects: Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11789 , http://hdl.handle.net/10353/272 , Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Description: Dasineura sp. is a gall forming midge that was introduced into South Africa for the biocontrol of the Australian myrtle, Leptospermum laevigatum. It causes galls on both the vegetative and reproductive buds of the plant. Although Dasineura sp. was initially regarded as a potentially successful agent, galling up to 99 percent of the buds of the host plant, it has been preyed on by native opportunistic mites, which caused a decline in the performance of the midge as a biocontrol agent of L. laevigatum. This raised a concern about whether this fly will be able to perform effectively in the presence of its new natural enemies. Therefore, the objectives of this study were to: 1) ascertain whether mite abundance has seasonal variations; 2) determine if plant density and plant size have an effect on midge predation by the mites; and 3) determine if midge predation varies in different locations. The study was conducted at three sites in the Hermanus area, Western Cape Province. Every three weeks for thirteen months, galls were collected and dissected so as to count and record the numbers of midge larvae, pupae, adults and mites that were found. Data collected showed that predation varied with season, and the mites were scarce during the flowering season. Predation also varied among the study sites and plant density had an effect on midge predation. Midges in smaller plants (saplings) were more vulnerable to predation than those in the bigger plants (plants from isolates and thickets). It was concluded that although mites have an effect on midge populations, they do not prevent their establishment on the plant. Therefore, a survey should be done in two to three years time to check if the midges are still persisting on the plant, vi and recommendations are that a new agent should be released to supplement the midges.
- Full Text:
- Date Issued: 2010
- Authors: Mdlangu, Thabisa Lynette Honey
- Date: 2010
- Subjects: Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11789 , http://hdl.handle.net/10353/272 , Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Description: Dasineura sp. is a gall forming midge that was introduced into South Africa for the biocontrol of the Australian myrtle, Leptospermum laevigatum. It causes galls on both the vegetative and reproductive buds of the plant. Although Dasineura sp. was initially regarded as a potentially successful agent, galling up to 99 percent of the buds of the host plant, it has been preyed on by native opportunistic mites, which caused a decline in the performance of the midge as a biocontrol agent of L. laevigatum. This raised a concern about whether this fly will be able to perform effectively in the presence of its new natural enemies. Therefore, the objectives of this study were to: 1) ascertain whether mite abundance has seasonal variations; 2) determine if plant density and plant size have an effect on midge predation by the mites; and 3) determine if midge predation varies in different locations. The study was conducted at three sites in the Hermanus area, Western Cape Province. Every three weeks for thirteen months, galls were collected and dissected so as to count and record the numbers of midge larvae, pupae, adults and mites that were found. Data collected showed that predation varied with season, and the mites were scarce during the flowering season. Predation also varied among the study sites and plant density had an effect on midge predation. Midges in smaller plants (saplings) were more vulnerable to predation than those in the bigger plants (plants from isolates and thickets). It was concluded that although mites have an effect on midge populations, they do not prevent their establishment on the plant. Therefore, a survey should be done in two to three years time to check if the midges are still persisting on the plant, vi and recommendations are that a new agent should be released to supplement the midges.
- Full Text:
- Date Issued: 2010
Assessing the diet of the Cape leopard (panthera pardus) in the Cederberg and Gamka mountains, South Africa
- Authors: Rautenbach, Therèsè
- Date: 2010
- Subjects: Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10699 , http://hdl.handle.net/10948/1078 , Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Description: As limited prey availability and persecution by humans in response to livestock predation are key conservation concerns for the Cape leopard (Martins & Martins 2006), the present study aimed to provide more information regarding their feeding habits. The first objective was to determine whether the Cape leopard was subject to a change in their prey base and how they responded to the change. This was established by comparison of their current diet in the Cederberg and Gamka Mountains, determined by using scat analysis techniques, with a previous dietary assessment (Norton et al. 1986). The second aim was to provide a preliminary assessment of the prey preference of the Cape leopard and examine the utility of camera trap surveys to determine leopard prey preference. Leopard diet in the Cederberg and Gamka Mountains consisted largely of small- (1-10 kg) and medium-sized (10-40 kg) mammals; rock hyraxes (Procavia capensis) and klipspringers (Oreotragus oreotragus) were key prey items. In terms of regional variation in leopard diet, there was a significant difference in the average weight of prey utilized in the Cederberg and Gamka Mountains. Despite the importance of prey availability of suitable size, their flexibility in terms of prey size utilization reflected their ability to switch to smaller prey to fulfil their dietary requirements, when prey is limited. The study suggested a dietary shift, with significant variation in prey species utilization in both regions. The shift did not appear to be in response to prey scarcity, but rather a reduction in key prey species, particularly the rock hyrax. The shift involved an increase in the number of species utilized, and only a very small increase in livestock predation in both areas. There was however no significant variation in prey size category utilization. This demonstrated their dietary flexibility, as well as the importance of suitable prey sizes rather than the presence of specific prey species to fulfil their dietary requirements. The camera trap survey revealed a strong correlation between the number of camera trap days and the number of photographs taken of identifiable species. Variation of this correlation between different habitats supported the notion that individual images are a better unit to determine sampling efficiency than trap days. The camera trap survey also showed that small rodent availability was underestimated by camera trap surveillance, which resulted in poor prey preference estimation. It was therefore suggested that camera trap surveys be restricted to the surveillance of larger prey species (> 1 kg). By excluding small rodents from the analysis, prey preference could be estimated for other species and prey size categories. Small- and medium-sized mammals were significantly preferred, whereas large mammals were significantly avoided by the Cape leopard.
- Full Text:
- Date Issued: 2010
- Authors: Rautenbach, Therèsè
- Date: 2010
- Subjects: Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10699 , http://hdl.handle.net/10948/1078 , Leopard -- South Africa , Animal feeding -- South Africa , Predation (Biology)
- Description: As limited prey availability and persecution by humans in response to livestock predation are key conservation concerns for the Cape leopard (Martins & Martins 2006), the present study aimed to provide more information regarding their feeding habits. The first objective was to determine whether the Cape leopard was subject to a change in their prey base and how they responded to the change. This was established by comparison of their current diet in the Cederberg and Gamka Mountains, determined by using scat analysis techniques, with a previous dietary assessment (Norton et al. 1986). The second aim was to provide a preliminary assessment of the prey preference of the Cape leopard and examine the utility of camera trap surveys to determine leopard prey preference. Leopard diet in the Cederberg and Gamka Mountains consisted largely of small- (1-10 kg) and medium-sized (10-40 kg) mammals; rock hyraxes (Procavia capensis) and klipspringers (Oreotragus oreotragus) were key prey items. In terms of regional variation in leopard diet, there was a significant difference in the average weight of prey utilized in the Cederberg and Gamka Mountains. Despite the importance of prey availability of suitable size, their flexibility in terms of prey size utilization reflected their ability to switch to smaller prey to fulfil their dietary requirements, when prey is limited. The study suggested a dietary shift, with significant variation in prey species utilization in both regions. The shift did not appear to be in response to prey scarcity, but rather a reduction in key prey species, particularly the rock hyrax. The shift involved an increase in the number of species utilized, and only a very small increase in livestock predation in both areas. There was however no significant variation in prey size category utilization. This demonstrated their dietary flexibility, as well as the importance of suitable prey sizes rather than the presence of specific prey species to fulfil their dietary requirements. The camera trap survey revealed a strong correlation between the number of camera trap days and the number of photographs taken of identifiable species. Variation of this correlation between different habitats supported the notion that individual images are a better unit to determine sampling efficiency than trap days. The camera trap survey also showed that small rodent availability was underestimated by camera trap surveillance, which resulted in poor prey preference estimation. It was therefore suggested that camera trap surveys be restricted to the surveillance of larger prey species (> 1 kg). By excluding small rodents from the analysis, prey preference could be estimated for other species and prey size categories. Small- and medium-sized mammals were significantly preferred, whereas large mammals were significantly avoided by the Cape leopard.
- Full Text:
- Date Issued: 2010
A bioinorganic investigation of some metal complexes of the Schiff base, N,N'-bis(3-methoxysalicylaldimine)propan-2-ol
- Authors: Mopp, Estelle
- Date: 2010 , 2012-04-13
- Subjects: Schiff bases , Bioinorganic chemistry , Metal complexes , Transition metal complexes , Transition metals , Cancer -- Chemotherapy , Ligands -- Toxicity , Antineoplastic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4413 , http://hdl.handle.net/10962/d1006768 , Schiff bases , Bioinorganic chemistry , Metal complexes , Transition metal complexes , Transition metals , Cancer -- Chemotherapy , Ligands -- Toxicity , Antineoplastic agents
- Description: This thesis includes the synthesis, characterisation, antioxidant and antimicrobial activities of Cu(II)-, Co(II)- and Co(III) complexes with N,N'-bis(3- methoxysalicylaldimine)propan-2-ol, 2-OH-oVANPN. The Schiff base ligand, 2-OHoVANPN, is derived from o-vanillin and 1,3-diaminopropan-2-ol. The o-vanillin condensed with 1,3-diaminopropan-2-ol in a 2:1 molar ratio yields this potential tetraor pentadentate ligand. The complexes synthesized are tetra (or penta or hexa) coordinated. Formation of the complexes is symbolized as follows:- MX₂ + 2-OH-oVANPN (2:1) -> [M(2-OH-oVANPN)Xn] + HnX MX₂ + 2-OH-oVANPN (2:1) -> [Mn(2-OH-oVANPN)OH] + H₂X₂ MX₂ + (o-vanillin : diaminopropanol) (1:1) -> [M(1:1)X₂] MX₂ + (o-vanillin : diaminopropanol) (1:1) -> [M₃(1:1)X₄] M = Cu(II), Co(II) or Co(III); X = Cl; n = 1, 2. Their structural features have been deduced from their elemental analytical data, IR spectral data, and electronic spectral data. With the exception of {Cu₃(C₁₁H₁₄N₂O₃)(Cl)₄(H₂O)₆}(A4), the Cu(II) complexes were monomeric with 2-OH-oVANPN acting as a tetradentate ligand. A binuclear Co(II) complex, [Co₂(C₁₉H₁₉N₂O₅)(OH)] (B1), was synthesised and the rest of the Co(II) and Co(III) complexes were monomeric with chloride ions coordinating to the metal centre in some cases. Electronic data suggest that the cobalt(II) complexes have octahedral geometries and the copper(II) complexes have square planar structures – Co(III) is likely to be octahedral. Thermal analyses, which included the copper-block-method for determining sublimation temperatures, revealed that some copper(II) and cobalt(II) complexes are hygroscopic and sublime at 200 °C and below. DSC analyses of the Cu(II) complexes gave exotherms around 300 °C for complexes K[Cu(C₁₉H₂₀N₂O₅)(OH)]·2H₂O (A1) and [Cu(C₁₁H15N₂O₃)(Cl)₂]·2H₂O (A2) and above 400 °C for [Cu(C₁₁H₁₆N₂O₃)(Cl)₂] (A3) and {Cu₃(C₁₁H₁₄N₂O₃)(Cl)₄(H₂O)₆} (A4). Antioxidant studies were carried out against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·). The cobalt(II) complex, [Co₂(C₁₉H₁₉N₂O₅)(OH)] (B1), which was synthesized in the presence of KOH, had no antioxidant activity, whilst the other cobalt(II) complexes, [Co(C₁₇H₁₇N₂O₅(Cl))]·1½H₂O (B2), [Co(C₁₉H₂₂N₂O₅) (Cl)₂]·5½H₂O (B3) and [Co(C₁₉H₂₂N₂O₅)(Cl)₂]·5½H₂O (B4), which were synthesised in the absence of KOH, demonstrated antioxidant activity. The latter complexes are candidates for cancer cell line testing, while [Cu(C₁₁H₁₆N₂O₃)(Cl)₂] (A3), {Cu₃(C₁₁H₁₄N₂O₃)(Cl)₄(H₂O)₆} (A4), [Co(C₁₉H₂₁N₂O₅)(Cl)₂ ]·5H₂O (C2) and [Co(C₁₉H₂₀N₂O₅)(Cl)]·3H₂O (C3) may show anticancer activity through possible hydrolysis products. Most of the complexes synthesized displayed antimicrobial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger and Candida albicans. The results indicated that complexes [Cu(C₁₁H₁₆N₂O₃)(Cl)₂](A3), [Co(C₁₉H₂₂N₂O₅)(Cl)₂]·5½H₂O (B3) and [Co(C₁₉H₂₁N₂O₅)(Cl)₂ ]·5H₂O (C2) are active against the Gram-negative Ps. aeruginosa and that the ligand, 2-OH-oVANPN, did not have any activity. The same trend was observed with 2-OH-oVANPN, {Cu₃(C₁₁H₁₄N₂O₃)(Cl)4(H₂O)₆} (A4) and [Co(C₁₉H₂₀N₂O₅)(Cl)]·3H₂O (C3) against the Gram-positive S. aureus. As for activity against E. coli and C. albicans, some complexes showed more activity than the ligand. There is an observed trend here that the metal complexes are more active (toxic) than the corresponding ligand, which is in agreement with Tweedy’s chelation theory.
- Full Text:
- Date Issued: 2010
- Authors: Mopp, Estelle
- Date: 2010 , 2012-04-13
- Subjects: Schiff bases , Bioinorganic chemistry , Metal complexes , Transition metal complexes , Transition metals , Cancer -- Chemotherapy , Ligands -- Toxicity , Antineoplastic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4413 , http://hdl.handle.net/10962/d1006768 , Schiff bases , Bioinorganic chemistry , Metal complexes , Transition metal complexes , Transition metals , Cancer -- Chemotherapy , Ligands -- Toxicity , Antineoplastic agents
- Description: This thesis includes the synthesis, characterisation, antioxidant and antimicrobial activities of Cu(II)-, Co(II)- and Co(III) complexes with N,N'-bis(3- methoxysalicylaldimine)propan-2-ol, 2-OH-oVANPN. The Schiff base ligand, 2-OHoVANPN, is derived from o-vanillin and 1,3-diaminopropan-2-ol. The o-vanillin condensed with 1,3-diaminopropan-2-ol in a 2:1 molar ratio yields this potential tetraor pentadentate ligand. The complexes synthesized are tetra (or penta or hexa) coordinated. Formation of the complexes is symbolized as follows:- MX₂ + 2-OH-oVANPN (2:1) -> [M(2-OH-oVANPN)Xn] + HnX MX₂ + 2-OH-oVANPN (2:1) -> [Mn(2-OH-oVANPN)OH] + H₂X₂ MX₂ + (o-vanillin : diaminopropanol) (1:1) -> [M(1:1)X₂] MX₂ + (o-vanillin : diaminopropanol) (1:1) -> [M₃(1:1)X₄] M = Cu(II), Co(II) or Co(III); X = Cl; n = 1, 2. Their structural features have been deduced from their elemental analytical data, IR spectral data, and electronic spectral data. With the exception of {Cu₃(C₁₁H₁₄N₂O₃)(Cl)₄(H₂O)₆}(A4), the Cu(II) complexes were monomeric with 2-OH-oVANPN acting as a tetradentate ligand. A binuclear Co(II) complex, [Co₂(C₁₉H₁₉N₂O₅)(OH)] (B1), was synthesised and the rest of the Co(II) and Co(III) complexes were monomeric with chloride ions coordinating to the metal centre in some cases. Electronic data suggest that the cobalt(II) complexes have octahedral geometries and the copper(II) complexes have square planar structures – Co(III) is likely to be octahedral. Thermal analyses, which included the copper-block-method for determining sublimation temperatures, revealed that some copper(II) and cobalt(II) complexes are hygroscopic and sublime at 200 °C and below. DSC analyses of the Cu(II) complexes gave exotherms around 300 °C for complexes K[Cu(C₁₉H₂₀N₂O₅)(OH)]·2H₂O (A1) and [Cu(C₁₁H15N₂O₃)(Cl)₂]·2H₂O (A2) and above 400 °C for [Cu(C₁₁H₁₆N₂O₃)(Cl)₂] (A3) and {Cu₃(C₁₁H₁₄N₂O₃)(Cl)₄(H₂O)₆} (A4). Antioxidant studies were carried out against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·). The cobalt(II) complex, [Co₂(C₁₉H₁₉N₂O₅)(OH)] (B1), which was synthesized in the presence of KOH, had no antioxidant activity, whilst the other cobalt(II) complexes, [Co(C₁₇H₁₇N₂O₅(Cl))]·1½H₂O (B2), [Co(C₁₉H₂₂N₂O₅) (Cl)₂]·5½H₂O (B3) and [Co(C₁₉H₂₂N₂O₅)(Cl)₂]·5½H₂O (B4), which were synthesised in the absence of KOH, demonstrated antioxidant activity. The latter complexes are candidates for cancer cell line testing, while [Cu(C₁₁H₁₆N₂O₃)(Cl)₂] (A3), {Cu₃(C₁₁H₁₄N₂O₃)(Cl)₄(H₂O)₆} (A4), [Co(C₁₉H₂₁N₂O₅)(Cl)₂ ]·5H₂O (C2) and [Co(C₁₉H₂₀N₂O₅)(Cl)]·3H₂O (C3) may show anticancer activity through possible hydrolysis products. Most of the complexes synthesized displayed antimicrobial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger and Candida albicans. The results indicated that complexes [Cu(C₁₁H₁₆N₂O₃)(Cl)₂](A3), [Co(C₁₉H₂₂N₂O₅)(Cl)₂]·5½H₂O (B3) and [Co(C₁₉H₂₁N₂O₅)(Cl)₂ ]·5H₂O (C2) are active against the Gram-negative Ps. aeruginosa and that the ligand, 2-OH-oVANPN, did not have any activity. The same trend was observed with 2-OH-oVANPN, {Cu₃(C₁₁H₁₄N₂O₃)(Cl)4(H₂O)₆} (A4) and [Co(C₁₉H₂₀N₂O₅)(Cl)]·3H₂O (C3) against the Gram-positive S. aureus. As for activity against E. coli and C. albicans, some complexes showed more activity than the ligand. There is an observed trend here that the metal complexes are more active (toxic) than the corresponding ligand, which is in agreement with Tweedy’s chelation theory.
- Full Text:
- Date Issued: 2010
Microbial ecology of the Buffalo River in response to water quality changes
- Authors: Zuma, Bongumusa Msizi
- Date: 2010
- Subjects: Water quality -- South Africa -- Buffalo River (Eastern Cape) , Microbial ecology -- South Africa -- Buffalo River (Eastern Cape) , River Health Programme (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6038 , http://hdl.handle.net/10962/d1006182 , Water quality -- South Africa -- Buffalo River (Eastern Cape) , Microbial ecology -- South Africa -- Buffalo River (Eastern Cape) , River Health Programme (South Africa)
- Description: South Africa’s freshwater quality and quantity is declining and consequently impacting on the ecological health of these ecosystems, due to increased agricultural, urban and industrial developments. The River Health Programme (RHP) was designed for monitoring and assessing the ecological health of freshwater ecosystems in South Africa, in order to effectively manage these aquatic resources. The RHP utilises biological indicators such as in-stream biota as a structured and sensitive tool for assessing ecosystem health. Although the RHP has been widely implemented across South Africa, no attempts have been made to explore microbial ecology as a tool that could be included as one of the RHP indices. This study used selected microbial responses and water physico-chemical parameters to assess the current water quality status of the Buffalo River. This study showed that water quality impairments compounded in the urban regions of King William’s Town and Zwelitsha and also downstream of the Bridle Drift Dam. The results also showed that the lower and the upper catchments of the Buffalo River were not significantly different in terms of water physico-chemistry and microbiology, as indicated by low stress levels of an NMDS plot. Though similarities were recorded between impacted and reference sites, the results strongly showed that known impacted sites recorded the poorest water physico-chemistry, including the Yellowwoods River. However, the Laing Dam provided a buffer effect on contributions of the Yellowwoods River into the Buffalo River. Multivariate analysis showed that microbial cell counts were not influenced by water physico-chemical changes, whilst microbial activity from the water and biofilm habitats showed significant correlation levels to water physico-chemical changes. This study demonstrated that further investigations towards exploitation of microbial activity responses to water physico-chemical quality changes should be channelled towards the development of microbiological assessment index for inclusion in the RHP.
- Full Text:
- Date Issued: 2010
- Authors: Zuma, Bongumusa Msizi
- Date: 2010
- Subjects: Water quality -- South Africa -- Buffalo River (Eastern Cape) , Microbial ecology -- South Africa -- Buffalo River (Eastern Cape) , River Health Programme (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6038 , http://hdl.handle.net/10962/d1006182 , Water quality -- South Africa -- Buffalo River (Eastern Cape) , Microbial ecology -- South Africa -- Buffalo River (Eastern Cape) , River Health Programme (South Africa)
- Description: South Africa’s freshwater quality and quantity is declining and consequently impacting on the ecological health of these ecosystems, due to increased agricultural, urban and industrial developments. The River Health Programme (RHP) was designed for monitoring and assessing the ecological health of freshwater ecosystems in South Africa, in order to effectively manage these aquatic resources. The RHP utilises biological indicators such as in-stream biota as a structured and sensitive tool for assessing ecosystem health. Although the RHP has been widely implemented across South Africa, no attempts have been made to explore microbial ecology as a tool that could be included as one of the RHP indices. This study used selected microbial responses and water physico-chemical parameters to assess the current water quality status of the Buffalo River. This study showed that water quality impairments compounded in the urban regions of King William’s Town and Zwelitsha and also downstream of the Bridle Drift Dam. The results also showed that the lower and the upper catchments of the Buffalo River were not significantly different in terms of water physico-chemistry and microbiology, as indicated by low stress levels of an NMDS plot. Though similarities were recorded between impacted and reference sites, the results strongly showed that known impacted sites recorded the poorest water physico-chemistry, including the Yellowwoods River. However, the Laing Dam provided a buffer effect on contributions of the Yellowwoods River into the Buffalo River. Multivariate analysis showed that microbial cell counts were not influenced by water physico-chemical changes, whilst microbial activity from the water and biofilm habitats showed significant correlation levels to water physico-chemical changes. This study demonstrated that further investigations towards exploitation of microbial activity responses to water physico-chemical quality changes should be channelled towards the development of microbiological assessment index for inclusion in the RHP.
- Full Text:
- Date Issued: 2010
Synthesis, characterization and reactions of novel ferrocenylimidazoles as donor ligands
- Authors: Onyancha, Douglas Okerio
- Date: 2010
- Subjects: Ferrocene
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10390 , http://hdl.handle.net/10948/1150 , Ferrocene
- Description: In this project a series of ferrocenylimidazole derivatives were successfully prepared and characterized using an array of analytical techniques. Reactions of ferrocenylcarbinols with N,N′-thiocarbonyldiimidazole under both solvent-free conditions and in dichloromethane are described. The reaction of ferrocenylmethanol afforded S,S-bis(ferrocenylmethyl)dithiocarbonate, the reaction of α-substituted ferrocenylcarbinols provided ferrocenylalkylimidazolides, while ω-ferrocenylcarbinols yielded ferrocenylimidazolecarbothioates. The reactions were carried out under solvent-free conditions, consistent with the principles of Green Chemistry. Ferrocenyl benzyl ethers were successfully prepared by reacting 4-ferrocenylbenzyl-1Hcarboxylate with a series of primary alcohols under catalytic condition and under a catalyst– free environment. Refluxing a mixture of alcohol-water and 4-ferrocenylbenzyl-1Hcarboxylate provided the corresponding ethers in modest yields. The same ethers were obtained at room temperature by employing potassium tetrachloroplatinate or hydrochloric acid as catalyst. Ferrocenyl-1H-imidazole, 4-ferrocenylphenyl-1H-imidazole and their corresponding ferrocenyl-3-subsitituted imidazolium salts have been successfully synthesized. The compounds were characterized and the electrochemical properties of selected imidazolium salts were examined by cyclic voltammetry. Additionally, X-ray structures of two of the imidazolium salts were determined. The imidazolium salts were found to be good catalysts for the Heck and Suzuki cross-coupling reactions.
- Full Text:
- Date Issued: 2010
- Authors: Onyancha, Douglas Okerio
- Date: 2010
- Subjects: Ferrocene
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10390 , http://hdl.handle.net/10948/1150 , Ferrocene
- Description: In this project a series of ferrocenylimidazole derivatives were successfully prepared and characterized using an array of analytical techniques. Reactions of ferrocenylcarbinols with N,N′-thiocarbonyldiimidazole under both solvent-free conditions and in dichloromethane are described. The reaction of ferrocenylmethanol afforded S,S-bis(ferrocenylmethyl)dithiocarbonate, the reaction of α-substituted ferrocenylcarbinols provided ferrocenylalkylimidazolides, while ω-ferrocenylcarbinols yielded ferrocenylimidazolecarbothioates. The reactions were carried out under solvent-free conditions, consistent with the principles of Green Chemistry. Ferrocenyl benzyl ethers were successfully prepared by reacting 4-ferrocenylbenzyl-1Hcarboxylate with a series of primary alcohols under catalytic condition and under a catalyst– free environment. Refluxing a mixture of alcohol-water and 4-ferrocenylbenzyl-1Hcarboxylate provided the corresponding ethers in modest yields. The same ethers were obtained at room temperature by employing potassium tetrachloroplatinate or hydrochloric acid as catalyst. Ferrocenyl-1H-imidazole, 4-ferrocenylphenyl-1H-imidazole and their corresponding ferrocenyl-3-subsitituted imidazolium salts have been successfully synthesized. The compounds were characterized and the electrochemical properties of selected imidazolium salts were examined by cyclic voltammetry. Additionally, X-ray structures of two of the imidazolium salts were determined. The imidazolium salts were found to be good catalysts for the Heck and Suzuki cross-coupling reactions.
- Full Text:
- Date Issued: 2010