Graphene quantum dots and their metallophthalocyanines nanoconjugates as novel photoluminescent nanosensors
- Authors: Achadu, Ojodomo John
- Date: 2018
- Subjects: Quantum dots , Graphene , Phthalocyanines , Nanoconjugates , Novel photoluminescent nanosensors , Metallophthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60719 , vital:27821
- Description: The fabrication and application of graphene quantum dots (GQDs)-based photoluminescent probes for the detection of analytes is presented. GQDs were functionalized with complexes such as metallophthalocyanines (MPcs), metal nanoparticles (Au@Ag NPs), 2,2,6,6-tetramethyl(piperidin-1-yl)oxyl (TEMPO), maleimide and thymine for the sensing of target analytes such as ascorbic acid (AA), biothiols (cysteine, homocysteine and glutathione) and mercury ion (Hg²+). The design strategy and approach was based on the quenching of the fluorescence of the GQDs upon functionalization with the above-mentioned complexes, which could be restored in the presence of the target analytes (due to their specific interaction affinity with the complexes). For the detection of AA, GQDs were covalently and/or non-covalently conjugated to TEMPO-bearing complexes to form GQDs-4A-TEMPO and GQDs-TEMPO-MPc systems with nanomolar limits of detection. For the detection of biothiols, Au@Ag NPs and maleimide-bearing complexes (MPc), which have specific affinity to interact with biothiols, were deployed. Hg²+ detection involved the use of GQDs and/or MPcs with thiol and thymine groups, respectively. In addition, a smart sensing platform was designed for the dual detection of biothiols and Hg²+ using supramolecular hybrid of polyethyleneimine functionalized-GQDs and MPc-Au@Ag conjugate. The probe could detect, in a sequential manner, Hg²+ and biothiols with high sensitivity. Results obtained from the LODs of the probes showed that GQDs sensing performances could be enhanced in the presence of MPcs. The probes designed in this work were successfully deployed in the assays of the target analytes in real samples and the recoveries obtained confirmed the analytical applicability of the probes.
- Full Text:
- Date Issued: 2018
- Authors: Achadu, Ojodomo John
- Date: 2018
- Subjects: Quantum dots , Graphene , Phthalocyanines , Nanoconjugates , Novel photoluminescent nanosensors , Metallophthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60719 , vital:27821
- Description: The fabrication and application of graphene quantum dots (GQDs)-based photoluminescent probes for the detection of analytes is presented. GQDs were functionalized with complexes such as metallophthalocyanines (MPcs), metal nanoparticles (Au@Ag NPs), 2,2,6,6-tetramethyl(piperidin-1-yl)oxyl (TEMPO), maleimide and thymine for the sensing of target analytes such as ascorbic acid (AA), biothiols (cysteine, homocysteine and glutathione) and mercury ion (Hg²+). The design strategy and approach was based on the quenching of the fluorescence of the GQDs upon functionalization with the above-mentioned complexes, which could be restored in the presence of the target analytes (due to their specific interaction affinity with the complexes). For the detection of AA, GQDs were covalently and/or non-covalently conjugated to TEMPO-bearing complexes to form GQDs-4A-TEMPO and GQDs-TEMPO-MPc systems with nanomolar limits of detection. For the detection of biothiols, Au@Ag NPs and maleimide-bearing complexes (MPc), which have specific affinity to interact with biothiols, were deployed. Hg²+ detection involved the use of GQDs and/or MPcs with thiol and thymine groups, respectively. In addition, a smart sensing platform was designed for the dual detection of biothiols and Hg²+ using supramolecular hybrid of polyethyleneimine functionalized-GQDs and MPc-Au@Ag conjugate. The probe could detect, in a sequential manner, Hg²+ and biothiols with high sensitivity. Results obtained from the LODs of the probes showed that GQDs sensing performances could be enhanced in the presence of MPcs. The probes designed in this work were successfully deployed in the assays of the target analytes in real samples and the recoveries obtained confirmed the analytical applicability of the probes.
- Full Text:
- Date Issued: 2018
Sociocultural and sociomaterial mediation of children’s connectedness-with-nature: a case study of Hobbiton
- Authors: Ward-Smith, Chesney Fenella
- Date: 2018
- Subjects: Environmental psychology South Africa Eastern Cape , Experiential learning South Africa Eastern Cape , Environmental education Activity programs South Africa Eastern Cape , Nature study Activity programs South Africa Eastern Cape , Outdoor education South Africa Eastern Cape , Ethnoecology
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/61918 , vital:28083
- Description: An increasingly large body of literature sees disconnection from nature as central to the convergent social-ecological crisis, rooted in anthropocentric ontologies. This study explored the potential for embodied, sociomaterial nature-based activities to engender shifts in children’s perceptions of, and sense of connectedness with, nature. Equally it explored how children’s socio-cultural-historical value positionings (SCHVP) mediated their perceptions of, and connectedness with, nature. The nature-based activities, spread over five-day camps, were located at Hobbiton-on-Hogsback, a centre that has existed for decades to provide experiential learning and graded exposure to natural spaces, aiming to increase environmental knowledge and nature-connection. The experiences of two groups of children from wide-ranging socioeconomic and socio-cultural backgrounds in the Eastern Cape Province of South Africa were explored using interpretive case study methodology. Through semi-structured interviews and focus groups with selected children (aged 10-14) and the Hobbiton staff members who worked with them, as well as participant observation, data were collected and analysed thematically. This study was guided by a layered theoretical framework that included Deep Ecology as an under-labourer, and Cultural Historical Activity Theory (CHAT) as a substantive, analytical framework. Interactions between participants’ SCHVP and the sociomateriality of the nature- based activities were analysed in relation to the children’s nature-perceptions and sense of Connectedness-With-Nature. The findings highlight both the importance of the children’s SCHVP and the sociomateriality of the nature-based activities in mediating their prior perceptions of, and connectedness with nature. The nature-based activities acted as a primary stimulus for developing environmental empathy, awareness and pro-environmental intentions. In essence, Hobbiton acted as a primary ‘seed planter’ towards greater feelings of Connectedness-With-Nature. However, recommendations are put forward for more decolonised, ethics-oriented and sociomaterial design of Hobbiton’s nature-based activities, with an emphasis on integrating children’s SCHVP into the pedagogical-design process in relation to the sociomaterial elements of the nature-based activities. Emically integrating the children’s multiplicities of knowing, doing, valuing and being into the pedagogical-design process could contribute to the decolonisation of nature-based experiences in such contexts cultural, socio and political diversity.
- Full Text:
- Date Issued: 2018
- Authors: Ward-Smith, Chesney Fenella
- Date: 2018
- Subjects: Environmental psychology South Africa Eastern Cape , Experiential learning South Africa Eastern Cape , Environmental education Activity programs South Africa Eastern Cape , Nature study Activity programs South Africa Eastern Cape , Outdoor education South Africa Eastern Cape , Ethnoecology
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/61918 , vital:28083
- Description: An increasingly large body of literature sees disconnection from nature as central to the convergent social-ecological crisis, rooted in anthropocentric ontologies. This study explored the potential for embodied, sociomaterial nature-based activities to engender shifts in children’s perceptions of, and sense of connectedness with, nature. Equally it explored how children’s socio-cultural-historical value positionings (SCHVP) mediated their perceptions of, and connectedness with, nature. The nature-based activities, spread over five-day camps, were located at Hobbiton-on-Hogsback, a centre that has existed for decades to provide experiential learning and graded exposure to natural spaces, aiming to increase environmental knowledge and nature-connection. The experiences of two groups of children from wide-ranging socioeconomic and socio-cultural backgrounds in the Eastern Cape Province of South Africa were explored using interpretive case study methodology. Through semi-structured interviews and focus groups with selected children (aged 10-14) and the Hobbiton staff members who worked with them, as well as participant observation, data were collected and analysed thematically. This study was guided by a layered theoretical framework that included Deep Ecology as an under-labourer, and Cultural Historical Activity Theory (CHAT) as a substantive, analytical framework. Interactions between participants’ SCHVP and the sociomateriality of the nature- based activities were analysed in relation to the children’s nature-perceptions and sense of Connectedness-With-Nature. The findings highlight both the importance of the children’s SCHVP and the sociomateriality of the nature-based activities in mediating their prior perceptions of, and connectedness with nature. The nature-based activities acted as a primary stimulus for developing environmental empathy, awareness and pro-environmental intentions. In essence, Hobbiton acted as a primary ‘seed planter’ towards greater feelings of Connectedness-With-Nature. However, recommendations are put forward for more decolonised, ethics-oriented and sociomaterial design of Hobbiton’s nature-based activities, with an emphasis on integrating children’s SCHVP into the pedagogical-design process in relation to the sociomaterial elements of the nature-based activities. Emically integrating the children’s multiplicities of knowing, doing, valuing and being into the pedagogical-design process could contribute to the decolonisation of nature-based experiences in such contexts cultural, socio and political diversity.
- Full Text:
- Date Issued: 2018
Indigenous and traditional musics in the school classroom : a re-evaluation of the South African Indigenous African Music (IAM) curriculum
- Authors: McConnachie, Boudina
- Date: 2017
- Subjects: Ethnomusicology , Indigenous people -- Music , Music -- Instruction and study -- Africa , Music -- Instruction and study -- Curricula -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21182 , http://hdl.handle.net/10962/6806
- Description: Musical ideals set by European standards and values, entrenched through colonial oppression and promoted by the continued veneration of Western culture need to be re-evaluated. Despite the intention of the ANC government, through the Department of Basic Education's Curriculum and Assessment Policy Statement music curricula, to integrate Indigenous Knowledge and musics into the South African classroom, evidence shows that opportunities to do so are not seized. With reference to the proclaimed values of an African sensibility in the model of the South African music education curriculum, the history of its development and the current pedagogical movement towards transformation in the production of knowledge and the inclusion of Indigenous Knowledge (IK), this thesis questions why teachers in government schools in South Africa are not executing the Indigenous African Music (IAM) syllabus in the CAPS FET music curriculum. Taking the history of music education and the development of curriculum models and frameworks into account, it interrogates what strategies could improve the application of the current music curriculum in government schools in South Africa. These questions are addressed in the thesis by way of a discussion of the music curriculum and what its praxis in the classroom reveals about its efficacy, through observations and personal experiences, the observations of teachers and student teachers, a comparison with the experience in Zimbabwe, and an analysis of the music curriculum as it is currently devised and implemented. Straddling three methodological approaches, namely the ethnographic, the autoethnographic and the action research approach this study finds that the CAPS FET music curriculum does provide realistic opportunities to engage with African Indigenous and traditional music. This, however, is dependent upon the training of the teacher, facilities available in the classroom and the prior knowledge of the learner. A fundamental flaw of this curriculum is the approach to practical assessment of Indigenous and traditional African musics and the lack of assessment criteria and practical guidelines. In addition, the findings suggest that the fault regarding implementation of the curriculum lies in the training of students (who become teachers) at tertiary level, where an integrated approach to skills development regarding Indigenous African music is suggested.
- Full Text:
- Date Issued: 2017
- Authors: McConnachie, Boudina
- Date: 2017
- Subjects: Ethnomusicology , Indigenous people -- Music , Music -- Instruction and study -- Africa , Music -- Instruction and study -- Curricula -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21182 , http://hdl.handle.net/10962/6806
- Description: Musical ideals set by European standards and values, entrenched through colonial oppression and promoted by the continued veneration of Western culture need to be re-evaluated. Despite the intention of the ANC government, through the Department of Basic Education's Curriculum and Assessment Policy Statement music curricula, to integrate Indigenous Knowledge and musics into the South African classroom, evidence shows that opportunities to do so are not seized. With reference to the proclaimed values of an African sensibility in the model of the South African music education curriculum, the history of its development and the current pedagogical movement towards transformation in the production of knowledge and the inclusion of Indigenous Knowledge (IK), this thesis questions why teachers in government schools in South Africa are not executing the Indigenous African Music (IAM) syllabus in the CAPS FET music curriculum. Taking the history of music education and the development of curriculum models and frameworks into account, it interrogates what strategies could improve the application of the current music curriculum in government schools in South Africa. These questions are addressed in the thesis by way of a discussion of the music curriculum and what its praxis in the classroom reveals about its efficacy, through observations and personal experiences, the observations of teachers and student teachers, a comparison with the experience in Zimbabwe, and an analysis of the music curriculum as it is currently devised and implemented. Straddling three methodological approaches, namely the ethnographic, the autoethnographic and the action research approach this study finds that the CAPS FET music curriculum does provide realistic opportunities to engage with African Indigenous and traditional music. This, however, is dependent upon the training of the teacher, facilities available in the classroom and the prior knowledge of the learner. A fundamental flaw of this curriculum is the approach to practical assessment of Indigenous and traditional African musics and the lack of assessment criteria and practical guidelines. In addition, the findings suggest that the fault regarding implementation of the curriculum lies in the training of students (who become teachers) at tertiary level, where an integrated approach to skills development regarding Indigenous African music is suggested.
- Full Text:
- Date Issued: 2017
Synthesis and structure-activity relationship studies of 1,4-naphthoquinone derivatives as potential anti-trypanosomal agents
- Authors: Chakaingesu, Chikomborero
- Date: 2014
- Subjects: African trypanosomiasis , Trypanosoma brucei , Naphthoquinone , Protozoan diseases , Drugs -- Structure-activity relationships , Millennium Development Goals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3873 , http://hdl.handle.net/10962/d1020959
- Description: Human African Trypanosomiasis (HAT) is an infectious, vector-borne protozoal disease which is amongst the so-called neglected diseases. In 2000, at a summit of the United Nations, eight Millennium Development Goals (MDGs) were set, to be achieved by 2015. MDG 6 states “to combat HIV/AIDS, malaria & other diseases”. With just under 2 years to go before the end of 2015, HAT is still thriving in developing countries. The drugs currently used for the treatment of HAT are in short supply, have severe side effects and those used to treat late stages of the disease are very difficult to administer. The aforementioned challenges call for research into this neglected disease in order to develop new, safe and easy-to-use medicines. Naphthoquinones are a class of compounds shown to possess anti-parasitic activity, amongst a variety of other biological activities, and therefore this pharmacophore was selected for this study. The purpose of this study was to synthesise derivatives of 2,3-dichloro-1,4- naphthoquinone to be tested for anti-trypanosomal activity and thereafter conduct structureactivity relationship studies. A series of reactions were carried out using thiophenol, phenol and aniline nucleophiles to synthesise thioether (-S-), ether (-O-) and amino (-NH-) derivatives of 2,3-dichloro-1,4-naphthoquinone with various halogen or methyl substituents. Purification of the products was carried out by recrystallisation. Nuclear magnetic resonance (NMR), infra-red (IR) and high pressure liquid chromatography coupled to an electro-spray ionisation mass spectrometer (HPLC-ESI-MS) were the analytical methods used for structural confirmation of the products. There were eighteen 1,4-naphthoquinone derivatives that were successfully synthesised using ethanolic solutions. Unfortunately, attempts to synthesise 1,4-naphthoquinones in reactions involving 2-(trifluoro-methyl)aniline and 2-isopropyl-5-methylphenol were unsuccessful, presumably due to steric hindrance by the bulky ortho-substituents. Although the aims of the synthetic procedures were to obtain both mono- and disubstituted products by nucleophilic displacement of the chlorine atom(s) of 2,3-dichloro-1,4- naphthoquinone, only monosubstituted products were obtained from substitution with aniline and phenol nucleophiles. Thiol nucleophiles, however, selectively yielded disubstituted products only. Synthesised naphthoquinone derivatives were tested against Trypanosoma brucei and calculation of the EC₅₀ values from the obtained dose-response curves was carried out using the four parametric equation. All the 1,4-naphthoquinones showed a degree of potency, except compounds 1b, 3c and 3e, which had little or lack of potency. Structure-activity relationship studies (SARs and QSARs) were carried out to determine which structural features or functional group substituents of the naphthoquinone derivatives contribute or take away from the desired anti-trypanosomal activity. It was found that compounds with the best in vitro anti-trypanosomal potencies in the series of analogous 1,4-naphthoquinone derivatives had EC₅₀ values in the range 2.137 to 2.884 μM. The most potent compound in the series was 2-chloro-3-(4-(trifluoromethyl)phenylamino)-1,4- naphthoquinone 1e; but it was 142-fold less potent than the reference standard of melarsoprol.
- Full Text:
- Date Issued: 2014
- Authors: Chakaingesu, Chikomborero
- Date: 2014
- Subjects: African trypanosomiasis , Trypanosoma brucei , Naphthoquinone , Protozoan diseases , Drugs -- Structure-activity relationships , Millennium Development Goals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3873 , http://hdl.handle.net/10962/d1020959
- Description: Human African Trypanosomiasis (HAT) is an infectious, vector-borne protozoal disease which is amongst the so-called neglected diseases. In 2000, at a summit of the United Nations, eight Millennium Development Goals (MDGs) were set, to be achieved by 2015. MDG 6 states “to combat HIV/AIDS, malaria & other diseases”. With just under 2 years to go before the end of 2015, HAT is still thriving in developing countries. The drugs currently used for the treatment of HAT are in short supply, have severe side effects and those used to treat late stages of the disease are very difficult to administer. The aforementioned challenges call for research into this neglected disease in order to develop new, safe and easy-to-use medicines. Naphthoquinones are a class of compounds shown to possess anti-parasitic activity, amongst a variety of other biological activities, and therefore this pharmacophore was selected for this study. The purpose of this study was to synthesise derivatives of 2,3-dichloro-1,4- naphthoquinone to be tested for anti-trypanosomal activity and thereafter conduct structureactivity relationship studies. A series of reactions were carried out using thiophenol, phenol and aniline nucleophiles to synthesise thioether (-S-), ether (-O-) and amino (-NH-) derivatives of 2,3-dichloro-1,4-naphthoquinone with various halogen or methyl substituents. Purification of the products was carried out by recrystallisation. Nuclear magnetic resonance (NMR), infra-red (IR) and high pressure liquid chromatography coupled to an electro-spray ionisation mass spectrometer (HPLC-ESI-MS) were the analytical methods used for structural confirmation of the products. There were eighteen 1,4-naphthoquinone derivatives that were successfully synthesised using ethanolic solutions. Unfortunately, attempts to synthesise 1,4-naphthoquinones in reactions involving 2-(trifluoro-methyl)aniline and 2-isopropyl-5-methylphenol were unsuccessful, presumably due to steric hindrance by the bulky ortho-substituents. Although the aims of the synthetic procedures were to obtain both mono- and disubstituted products by nucleophilic displacement of the chlorine atom(s) of 2,3-dichloro-1,4- naphthoquinone, only monosubstituted products were obtained from substitution with aniline and phenol nucleophiles. Thiol nucleophiles, however, selectively yielded disubstituted products only. Synthesised naphthoquinone derivatives were tested against Trypanosoma brucei and calculation of the EC₅₀ values from the obtained dose-response curves was carried out using the four parametric equation. All the 1,4-naphthoquinones showed a degree of potency, except compounds 1b, 3c and 3e, which had little or lack of potency. Structure-activity relationship studies (SARs and QSARs) were carried out to determine which structural features or functional group substituents of the naphthoquinone derivatives contribute or take away from the desired anti-trypanosomal activity. It was found that compounds with the best in vitro anti-trypanosomal potencies in the series of analogous 1,4-naphthoquinone derivatives had EC₅₀ values in the range 2.137 to 2.884 μM. The most potent compound in the series was 2-chloro-3-(4-(trifluoromethyl)phenylamino)-1,4- naphthoquinone 1e; but it was 142-fold less potent than the reference standard of melarsoprol.
- Full Text:
- Date Issued: 2014
Propagation and stress physiology of selected Subtropical Thicket species : towards increasing biodiversity at rehabilitation sites
- Authors: Louw, Merika
- Date: 2012
- Subjects: Biodiversity conservation , Plant physiology , Stress (Physiology) , Plant propagation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10758 , http://hdl.handle.net/10948/d1021115
- Description: Sundays Thicket and Spekboomveld vegetation in the Eastern Cape have experienced intensive and extensive degradation due to over-browsing by domestic stock. The Subtropical Thicket Restoration Project aims to take advantage of the high carbon sequestration potential of Portulacaria afra (Spekboom) and other Thicket species, to rehabilitate degraded Thicket by restoring biodiversity and ecosystem services, create job opportunities and socio-economic upliftment in local communities, and promote the trade of carbon credits generated by planting and „farming‟ with Spekboom truncheons, rather than domestic stock. Plant material (seeds and length of stem) was sourced from the farm Krompoort, outside Uitenhage in the Eastern Cape. The effectiveness of four different rooting media i.e. plain pool filter sand and 1:1 mixtures of pool filter sand with perlite, potting soil and Thicket soil, on the rooting of ten Thicket species, were tested. Species with the greatest percentage strike and mean root length on stem cuttings were succulent species, Crassula ovata (84 percent strike) and Portulacaria afra (97 percent), as was expected. The application of rooting hormone Seradix© No. 3 did not significantly promote cutting strike or increase mean root length in C. ovata and P. afra. Woody canopy shrub species with the greatest cutting strike and mean root length, overall, were Rhigozum obovatum (24 percent), Lycium cinereum and L. oxycarpum (21 percent), and Searsia longispina (19 percent). These species, as well as Grewia robusta (4 percent), are considered „easy-to-root‟ species, or of sufficient functional value in terms of their spinescence, flower and fruit production, and soil-binding capabilities. Very low percentage strike (<1 percent) and mean root length were achieved in Azima tetracantha, Carissa bispinosa and Gymnosporia polyacantha subsp. polyacantha. These species are considered unsuitable for propagation for rehabilitation purposes. Crassula ovata, L. cinereum, L. oxycarpum, P. afra and S. longispina cuttings produced longer roots when planted in Thicket soil, the same having been found in R. obovatum cuttings planted in perlite. Thicket soil was, therefore, best at promoting cutting strike and root growth in „easy-to-root‟ species. Plain pool filter sand was the only medium in which A. tetracantha, C. bispinosa and G. robusta, cuttings rooted, and perlite the only medium in which G. polyacantha subsp. polyacantha cuttings rooted. Potting soil did not promote significant cutting strike or root growth in any of the species tested. Physiological variables i.e. photosynthetic efficiency (chlorophyll a fluorescence, Fv/Fm) and stomatal conductance (mmol H2O m-2 s-1) were measured for ten Thicket species, including Portulacaria afra. Control plants were watered well once a week, and treatment plants were dried out for 30 days, rewatered on the 30th day and their recovery from drought stress monitored for a further 17 days. Species that responded poorly to drought stress were Gymnosporia buxifolia and Putterlickia pyracantha. In addition to Portulacaria afra, species that showed the fastest recovery and resprout after rewatering, were: Crassula ovata, Ehretia rigida, Grewia robusta, Lycium ferocissimum, Rhigozum obovatum and Searsia longispina. These species produced the smallest decline in volumetric moisture content of soil, and had the lowest decline in photosynthetic efficiency and stomatal conductance during simulated drought. Unlike C. ovata and P. afra, which are CAM or C3-CAM switching species, mortality of transplants will most likely be high, if not total, during transplantation, as this study was done at lower light and temperature, and higher humidity levels than experienced at rehabilitation sites. This study has shown that the reintroduction of propagated woody canopy shrubs and trees into degraded Thicket sites does not appear to be a practical or economical method of actively restoring biodiversity to rehabilitation sites. As woody climax species have been shown to return to sites planted with Spekboom truncheons through „natural regeneration‟ within approximately 50 years, future research efforts should focus on optimising restoration site selection and planting techniques in order to maximize carbon sequestration potential of planted truncheons, which will, in the long term, result in an environment that can support regeneration of the biodiversity to something resembling intact Thicket.
- Full Text:
- Date Issued: 2012
- Authors: Louw, Merika
- Date: 2012
- Subjects: Biodiversity conservation , Plant physiology , Stress (Physiology) , Plant propagation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10758 , http://hdl.handle.net/10948/d1021115
- Description: Sundays Thicket and Spekboomveld vegetation in the Eastern Cape have experienced intensive and extensive degradation due to over-browsing by domestic stock. The Subtropical Thicket Restoration Project aims to take advantage of the high carbon sequestration potential of Portulacaria afra (Spekboom) and other Thicket species, to rehabilitate degraded Thicket by restoring biodiversity and ecosystem services, create job opportunities and socio-economic upliftment in local communities, and promote the trade of carbon credits generated by planting and „farming‟ with Spekboom truncheons, rather than domestic stock. Plant material (seeds and length of stem) was sourced from the farm Krompoort, outside Uitenhage in the Eastern Cape. The effectiveness of four different rooting media i.e. plain pool filter sand and 1:1 mixtures of pool filter sand with perlite, potting soil and Thicket soil, on the rooting of ten Thicket species, were tested. Species with the greatest percentage strike and mean root length on stem cuttings were succulent species, Crassula ovata (84 percent strike) and Portulacaria afra (97 percent), as was expected. The application of rooting hormone Seradix© No. 3 did not significantly promote cutting strike or increase mean root length in C. ovata and P. afra. Woody canopy shrub species with the greatest cutting strike and mean root length, overall, were Rhigozum obovatum (24 percent), Lycium cinereum and L. oxycarpum (21 percent), and Searsia longispina (19 percent). These species, as well as Grewia robusta (4 percent), are considered „easy-to-root‟ species, or of sufficient functional value in terms of their spinescence, flower and fruit production, and soil-binding capabilities. Very low percentage strike (<1 percent) and mean root length were achieved in Azima tetracantha, Carissa bispinosa and Gymnosporia polyacantha subsp. polyacantha. These species are considered unsuitable for propagation for rehabilitation purposes. Crassula ovata, L. cinereum, L. oxycarpum, P. afra and S. longispina cuttings produced longer roots when planted in Thicket soil, the same having been found in R. obovatum cuttings planted in perlite. Thicket soil was, therefore, best at promoting cutting strike and root growth in „easy-to-root‟ species. Plain pool filter sand was the only medium in which A. tetracantha, C. bispinosa and G. robusta, cuttings rooted, and perlite the only medium in which G. polyacantha subsp. polyacantha cuttings rooted. Potting soil did not promote significant cutting strike or root growth in any of the species tested. Physiological variables i.e. photosynthetic efficiency (chlorophyll a fluorescence, Fv/Fm) and stomatal conductance (mmol H2O m-2 s-1) were measured for ten Thicket species, including Portulacaria afra. Control plants were watered well once a week, and treatment plants were dried out for 30 days, rewatered on the 30th day and their recovery from drought stress monitored for a further 17 days. Species that responded poorly to drought stress were Gymnosporia buxifolia and Putterlickia pyracantha. In addition to Portulacaria afra, species that showed the fastest recovery and resprout after rewatering, were: Crassula ovata, Ehretia rigida, Grewia robusta, Lycium ferocissimum, Rhigozum obovatum and Searsia longispina. These species produced the smallest decline in volumetric moisture content of soil, and had the lowest decline in photosynthetic efficiency and stomatal conductance during simulated drought. Unlike C. ovata and P. afra, which are CAM or C3-CAM switching species, mortality of transplants will most likely be high, if not total, during transplantation, as this study was done at lower light and temperature, and higher humidity levels than experienced at rehabilitation sites. This study has shown that the reintroduction of propagated woody canopy shrubs and trees into degraded Thicket sites does not appear to be a practical or economical method of actively restoring biodiversity to rehabilitation sites. As woody climax species have been shown to return to sites planted with Spekboom truncheons through „natural regeneration‟ within approximately 50 years, future research efforts should focus on optimising restoration site selection and planting techniques in order to maximize carbon sequestration potential of planted truncheons, which will, in the long term, result in an environment that can support regeneration of the biodiversity to something resembling intact Thicket.
- Full Text:
- Date Issued: 2012
Rhodes University Research Report 2012
- Rhodes University, Roberts, Jaine, Connan, Verna, Mantolo, Thumeka, Macgregor, Jill, Jacob, Patricia
- Authors: Rhodes University , Roberts, Jaine , Connan, Verna , Mantolo, Thumeka , Macgregor, Jill , Jacob, Patricia
- Date: 2012
- Language: English
- Type: Text
- Identifier: vital:567 , http://hdl.handle.net/10962/d1011985
- Description: [From Introduction] Rhodes University continued to grow in overall accredited research outputs in 2012, and in other forms of scholarship which enhance the intellectual space of the university. During the graduation ceremonies that followed the 2012 academic year, 2 288 students earned new qualifications. A record 948 students or 41 percent graduated with postgraduate degrees. We also celebrated a new University record of 63 PhD graduates, a wonderful achievement for the smallest university in the country. Our Science Faculty was a particularly noteworthy contributor to the postgraduate numbers, with 35 PhD graduates, 83 Master’s graduates and 132 honours graduates. The University’s Enrolment Plan outlines our intention of becoming a more postgraduate university, and our overall strategy is to enhance our contribution to knowledge production through research and scholarship. Rhodes is well-positioned for such a trajectory, and we look to strengthening our capacity to serve society in this way by striving to provide our academics with effective research support. In the latest Department of Higher Education and Training (DHET) Ministerial Report on National Research Outputs, Rhodes University is listed as having the third most favourable research output rate per capita (the accepted norm for measuring efficiency of investment in the research domain) in the South African university system, and the second highest percentage of academic staff with PhDs (56 percent). Other studies show that Rhodes has the top PhD graduation rate of South African Universities, and very good postgraduate throughput rates overall. We continue to give special attention to identifying potential new postgraduate and research niche areas and programmes, and to developing the appropriate institutional arrangements to effectively support larger numbers of Honours, Masters and Doctoral students, and further enhance their academic and social experiences. The audited result of our DHET submission of accredited research outputs for 2012 has not yet been received at the time of writing, so exact success rates in book and conference submissions are not yet known. These are the smaller components of our overall accredited outputs (in the previous year, books and accredited conference proceedings each contributed 7 percent of our total accredited publishing output, while journals contributed 86 percent). In 2012, Rhodes submitted 46.82 book and book chapter units for consideration (up by 33 percent on the 2011 submission), and 32.04 accredited conference proceeding weighted units (down by 8.6 percent on the 2011 submission, which in turn had been up 46.8 percent on the previous year’s submission).Year-on-year variance on the relatively small submission base in these categories is to be expected. The big component of Rhodes’ publication output, our journal publications, grew by 13.2 percent on the 2011 level to 350.47 units (the previous year has seen a 6 percent increase in this category), maintaining Rhodes’ position amongst the most research productive institutions in the South African Higher Education system. Coupled with Rhodes’ high volume of accredited journal outputs in relation to its size, a very pleasing quality measure is that 90 percent of Journal outputs (the highest proportion in the sector) appear in internationally accredited journal indices. Accredited outputs from thesis-based PhD and Masters graduates rose by 4.9 percent in 2012 to a new high for Rhodes (2011’s figure had grown by 15.4 percent over 2010, which in turn had grown by 35.8 percent over 2009). I add my warm thanks and congratulations to all of our researchers, funders, collaborators and partners who contributed to the excellent accredited research results of 2012, as well as generated the many forms of scholarship that are not counted in the accreditation exercise, but which contribute much to the rich intellectual space that is Rhodes. I also thank all of the administrators who play a crucial role in preparing the university’s meticulous audited submissions.
- Full Text:
- Date Issued: 2012
- Authors: Rhodes University , Roberts, Jaine , Connan, Verna , Mantolo, Thumeka , Macgregor, Jill , Jacob, Patricia
- Date: 2012
- Language: English
- Type: Text
- Identifier: vital:567 , http://hdl.handle.net/10962/d1011985
- Description: [From Introduction] Rhodes University continued to grow in overall accredited research outputs in 2012, and in other forms of scholarship which enhance the intellectual space of the university. During the graduation ceremonies that followed the 2012 academic year, 2 288 students earned new qualifications. A record 948 students or 41 percent graduated with postgraduate degrees. We also celebrated a new University record of 63 PhD graduates, a wonderful achievement for the smallest university in the country. Our Science Faculty was a particularly noteworthy contributor to the postgraduate numbers, with 35 PhD graduates, 83 Master’s graduates and 132 honours graduates. The University’s Enrolment Plan outlines our intention of becoming a more postgraduate university, and our overall strategy is to enhance our contribution to knowledge production through research and scholarship. Rhodes is well-positioned for such a trajectory, and we look to strengthening our capacity to serve society in this way by striving to provide our academics with effective research support. In the latest Department of Higher Education and Training (DHET) Ministerial Report on National Research Outputs, Rhodes University is listed as having the third most favourable research output rate per capita (the accepted norm for measuring efficiency of investment in the research domain) in the South African university system, and the second highest percentage of academic staff with PhDs (56 percent). Other studies show that Rhodes has the top PhD graduation rate of South African Universities, and very good postgraduate throughput rates overall. We continue to give special attention to identifying potential new postgraduate and research niche areas and programmes, and to developing the appropriate institutional arrangements to effectively support larger numbers of Honours, Masters and Doctoral students, and further enhance their academic and social experiences. The audited result of our DHET submission of accredited research outputs for 2012 has not yet been received at the time of writing, so exact success rates in book and conference submissions are not yet known. These are the smaller components of our overall accredited outputs (in the previous year, books and accredited conference proceedings each contributed 7 percent of our total accredited publishing output, while journals contributed 86 percent). In 2012, Rhodes submitted 46.82 book and book chapter units for consideration (up by 33 percent on the 2011 submission), and 32.04 accredited conference proceeding weighted units (down by 8.6 percent on the 2011 submission, which in turn had been up 46.8 percent on the previous year’s submission).Year-on-year variance on the relatively small submission base in these categories is to be expected. The big component of Rhodes’ publication output, our journal publications, grew by 13.2 percent on the 2011 level to 350.47 units (the previous year has seen a 6 percent increase in this category), maintaining Rhodes’ position amongst the most research productive institutions in the South African Higher Education system. Coupled with Rhodes’ high volume of accredited journal outputs in relation to its size, a very pleasing quality measure is that 90 percent of Journal outputs (the highest proportion in the sector) appear in internationally accredited journal indices. Accredited outputs from thesis-based PhD and Masters graduates rose by 4.9 percent in 2012 to a new high for Rhodes (2011’s figure had grown by 15.4 percent over 2010, which in turn had grown by 35.8 percent over 2009). I add my warm thanks and congratulations to all of our researchers, funders, collaborators and partners who contributed to the excellent accredited research results of 2012, as well as generated the many forms of scholarship that are not counted in the accreditation exercise, but which contribute much to the rich intellectual space that is Rhodes. I also thank all of the administrators who play a crucial role in preparing the university’s meticulous audited submissions.
- Full Text:
- Date Issued: 2012
A socio-economic study of East London, Cape Province, with special reference to the non-European peoples
- Authors: Bettison, D G
- Date: 1951
- Subjects: East London (South Africa) -- Social conditions , East London (South Africa) -- Economic conditions , Rural-urban migration -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3387 , http://hdl.handle.net/10962/d1013496
- Description: From Forward: The development of gold mines in the Orange Free State is likely to be to modern East London what Kaffir Wars were to old East London. "The Fighting Port", as it is commonly called, is the nearest harbour to these mines and is linked by good rail, road and air facilities. A wide variety of industry is already established. Development is likely to be rapid. At present the City contains over 80,000 persons, and with the addition of peri-urban suburbs has doubled its population in just over fifteen years. In the past is has claimed to be the healthiest holiday resort in the Union. This year a City-wide campaign has been organised to fight tuberculosis, as the City's statistics indicate that it has one of the highest rates of anywhere in the world. Within twelve years two government sided commissions of enquiry have sat in the City and reported on the administration and living conditions of the city's African populaton. Extremely strong adjectives have been used to describe, and drastic recommendations made to improve the socio-economic and general conditions of the African people. Under the holiday atmosphere of the City lies a very serious, complex, and potentially dangerous human problem.
- Full Text:
- Date Issued: 1951
- Authors: Bettison, D G
- Date: 1951
- Subjects: East London (South Africa) -- Social conditions , East London (South Africa) -- Economic conditions , Rural-urban migration -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3387 , http://hdl.handle.net/10962/d1013496
- Description: From Forward: The development of gold mines in the Orange Free State is likely to be to modern East London what Kaffir Wars were to old East London. "The Fighting Port", as it is commonly called, is the nearest harbour to these mines and is linked by good rail, road and air facilities. A wide variety of industry is already established. Development is likely to be rapid. At present the City contains over 80,000 persons, and with the addition of peri-urban suburbs has doubled its population in just over fifteen years. In the past is has claimed to be the healthiest holiday resort in the Union. This year a City-wide campaign has been organised to fight tuberculosis, as the City's statistics indicate that it has one of the highest rates of anywhere in the world. Within twelve years two government sided commissions of enquiry have sat in the City and reported on the administration and living conditions of the city's African populaton. Extremely strong adjectives have been used to describe, and drastic recommendations made to improve the socio-economic and general conditions of the African people. Under the holiday atmosphere of the City lies a very serious, complex, and potentially dangerous human problem.
- Full Text:
- Date Issued: 1951
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