Characterisation of single event effects and total ionising dose effects of an intel atom microprocessor
- Authors: Malinda, Muema
- Date: 2019
- Subjects: Microprocessors , Mechatronics
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/41875 , vital:36605
- Description: The rapid advancements of COTS microprocessors compared to radiation hardened microprocessors has attracted the interest of system designers within the aerospace sector. COTS microprocessors offer higher performance with lower energy requirements, both of which are desired characteristics for microprocessors used in spacecraft. COTS microprocessors, however, are much more susceptible to radiation damage therefore their SEE and TID responses needs to be evaluated before they can be incorporated into spacecraft. This thesis presents the process followed to evaluate said characteristics of a COTS Intel Atom E3815 microprocessor mounted on a DE3815TYBE single board PC. Evaluation of the SEE response was carried out at NRF iThemba Labs in Cape Town, South Africa where the device was irradiated by a proton beam at 55.58 MeV and with varying beam currents. The device showed a higher sensitivity to functional interrupts when running with the onboard cache on compared to when running with the cache off, as would be expected. The cross-sections, respectively, are: 4.5𝑥 10−10 𝑐𝑚2 and 2.8 𝑥 10−10 𝑐𝑚2. TID testing on the other hand was carried out at the irradiation chamber of FruitFly Africa in Stellenbosch, South Africa. The test device was irradiated by gamma radiation from a Cobalt-60 source at a dose rate of 9.7kRad/h and to a total dose of 67.25kRad. Noticeable TID degradation, in the form of leakage currents, was observed once a total dose of about 20kRad was absorbed. The device then completely failed once a total dose of approximately 32kRad was absorbed. These results suggest that the E3815 microprocessor would not be suitable for long term missions that require higher TID survivability. The processor could however be considered for short term missions launched into polar or high incline orbits where the dose rate is relatively low, and the mission is capable of tolerating functional interrupts.
- Full Text:
- Date Issued: 2019
- Authors: Malinda, Muema
- Date: 2019
- Subjects: Microprocessors , Mechatronics
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/41875 , vital:36605
- Description: The rapid advancements of COTS microprocessors compared to radiation hardened microprocessors has attracted the interest of system designers within the aerospace sector. COTS microprocessors offer higher performance with lower energy requirements, both of which are desired characteristics for microprocessors used in spacecraft. COTS microprocessors, however, are much more susceptible to radiation damage therefore their SEE and TID responses needs to be evaluated before they can be incorporated into spacecraft. This thesis presents the process followed to evaluate said characteristics of a COTS Intel Atom E3815 microprocessor mounted on a DE3815TYBE single board PC. Evaluation of the SEE response was carried out at NRF iThemba Labs in Cape Town, South Africa where the device was irradiated by a proton beam at 55.58 MeV and with varying beam currents. The device showed a higher sensitivity to functional interrupts when running with the onboard cache on compared to when running with the cache off, as would be expected. The cross-sections, respectively, are: 4.5𝑥 10−10 𝑐𝑚2 and 2.8 𝑥 10−10 𝑐𝑚2. TID testing on the other hand was carried out at the irradiation chamber of FruitFly Africa in Stellenbosch, South Africa. The test device was irradiated by gamma radiation from a Cobalt-60 source at a dose rate of 9.7kRad/h and to a total dose of 67.25kRad. Noticeable TID degradation, in the form of leakage currents, was observed once a total dose of about 20kRad was absorbed. The device then completely failed once a total dose of approximately 32kRad was absorbed. These results suggest that the E3815 microprocessor would not be suitable for long term missions that require higher TID survivability. The processor could however be considered for short term missions launched into polar or high incline orbits where the dose rate is relatively low, and the mission is capable of tolerating functional interrupts.
- Full Text:
- Date Issued: 2019
Characterization and antibiogram fingerprints of Enterobacteriaceae and Listeria monocytogenes in irrigation water and agricultural soil samples collected from Amathole and Chris Hani District Municipalities in the Eastern Cape Province, South Africa
- Authors: Iwu, Chidozie Declan
- Date: 2019
- Subjects: Listeria monocytogenes Enterobacteriaceae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17187 , vital:40864
- Description: Characterization and antibiogram fingerprints of Enterobacteriaceae and Listeria monocytogenes in irrigation water and agricultural soil samples collected from Amathole and Chris Hani District Municipalities in the Eastern Cape Province, South Africa
- Full Text:
- Date Issued: 2019
- Authors: Iwu, Chidozie Declan
- Date: 2019
- Subjects: Listeria monocytogenes Enterobacteriaceae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17187 , vital:40864
- Description: Characterization and antibiogram fingerprints of Enterobacteriaceae and Listeria monocytogenes in irrigation water and agricultural soil samples collected from Amathole and Chris Hani District Municipalities in the Eastern Cape Province, South Africa
- Full Text:
- Date Issued: 2019
Characterization of electrodes modified with nanocomposites of cobalt tetraaminophenoxyphthalocyanine, reduced graphene and multi-walled carbon nanotubes
- Shumba, Munyaradz, Nyoni, Stephen, Britton, Jonathan, Nyokong, Tebello
- Authors: Shumba, Munyaradz , Nyoni, Stephen , Britton, Jonathan , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187003 , vital:44555 , xlink:href="https://doi.org/10.1080/00958972.2019.1621299"
- Description: Glassy carbon electrodes or plates were modified with nanocomposites consisting of cobalt tetraaminophenoxyphthalocyanine (CoTAPhPc), reduced graphene oxide nanosheets (rGONs) and multi-walled carbon nanotubes (MWCNTs). The modified electrodes were characterized using cyclic voltammetry, scanning electrochemical microscopy (SECM) and time-of-flight-secondary ion mass spectrometer (TOF-SIMS). The electrocatalytic activity of the modified electrode was tested for detection of L-cysteine. The presence of CoTAPhPc on sequential layers of MWCNT and rGONs resulted in improved detection currents compared to CoTAPhPc alone or when MWCNT/rGONs are mixed in CoTAPhPc–MWCNT/ rGONs (mix)–glassy carbon electrode (GCE). CoTAPhPc–MWCNT–GCE (without rGONS) showed higher sensitivity toward L-cysteine as compared to the probes incorporating rGONs with a catalytic rate constant of 4.62x104 M-1 s-1 and a detection limit of 30 nM. The presence of rGONs improved the stability of the electrode.
- Full Text:
- Date Issued: 2019
- Authors: Shumba, Munyaradz , Nyoni, Stephen , Britton, Jonathan , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187003 , vital:44555 , xlink:href="https://doi.org/10.1080/00958972.2019.1621299"
- Description: Glassy carbon electrodes or plates were modified with nanocomposites consisting of cobalt tetraaminophenoxyphthalocyanine (CoTAPhPc), reduced graphene oxide nanosheets (rGONs) and multi-walled carbon nanotubes (MWCNTs). The modified electrodes were characterized using cyclic voltammetry, scanning electrochemical microscopy (SECM) and time-of-flight-secondary ion mass spectrometer (TOF-SIMS). The electrocatalytic activity of the modified electrode was tested for detection of L-cysteine. The presence of CoTAPhPc on sequential layers of MWCNT and rGONs resulted in improved detection currents compared to CoTAPhPc alone or when MWCNT/rGONs are mixed in CoTAPhPc–MWCNT/ rGONs (mix)–glassy carbon electrode (GCE). CoTAPhPc–MWCNT–GCE (without rGONS) showed higher sensitivity toward L-cysteine as compared to the probes incorporating rGONs with a catalytic rate constant of 4.62x104 M-1 s-1 and a detection limit of 30 nM. The presence of rGONs improved the stability of the electrode.
- Full Text:
- Date Issued: 2019
Characterization of termite Trinervitermes trinervoides metagenome-derived glycoside hydrolases, the formulation of synergistic core enzyme sets for effective sweet sorghum and corncob saccharification, and their potential industrial applications
- Authors: Mafa, Mpho Stephen
- Date: 2019
- Subjects: Termites , Metagenomics , Glucosides , Hydrolases , Enzymes , Feedstock
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/72414 , vital:30044 , DOI https://doi.org/10.21504/10962/72414
- Description: The current study investigated the biochemical properties of endo-glucanase (GH5E), exo-glucanase (GH5D), xylanase (GH5H) and endo-glucanase/xylanase (GH45), derived from the hindgut bacterial symbionts of a termite (Trinervitermes trinervoides) for their potential role in the biotechnology industry. All these enzymes, except GH5D, exhibited activities on cellulosic and xylan-rich polymeric substrates, which only displayed activity on p-nitrophenyl cellobioside. GH5D, GH5E, GH5H and GH45 enzymes retained more than 80% of their activities at pH 5.5 and also retained more than 80% of their activities at 40ºC. Furthermore, these enzymes were thermostable at 37ºC for 72 hours. GH5E, GH5H and GH45 were generally stable over a range of metal-ion. The kinetic parameters for GH5E were 5.68 mg/ml (KM) and 34.36 U/mg protein (Vmax). GH5D activity did not follow classical Michaelis-Menten kinetics, suggesting product inhibition. GH5H displayed KM values of 5.53, 95.03 and 2.10 mg/ml and Vmax values of 112.36, 144.45 and 180.32 U/mg protein on beechwood xylan, CMC, and xyloglucan, respectively. GH45 displayed a KM of 6.94 mg/ml and a Vmax of 12.30 U/mg protein on CMC. GH5D [cellobiohydrolase (CBH)] and a commercial CBHII (GH6) enzyme outperformed a commercial CBHI (GH7) enzyme when these enzymes hydrolysed β-glucan. GH5D and CBHII also displayed a higher degree of synergy on β-glucan but failed to show synergy on Avicel. We therefore concluded that GH5D and CBHII are β-glucan-specific cellobiohydrolases. The corncob (CC) and sweet sorghum bagasse (SSB) substrates were pretreated with lime, NaOH and NaClO2. Subsequent to pretreatment, these substrates were used to investigate if GH5D, GH5E, GH5H and GH45 could operate in synergy. Results revealed that out of 12 possible core enzyme sets constructed, only two (referred to as CES-E and CES-H) displayed higher activities on pretreated CC or SSB. Simultaneous synergy was generally the most effective mode of synergy during hydrolysis of alkaline pretreated SSB and CC samples by both CES-E and CES-H. Both core enzyme sets did not display synergy on oxidative pretreated substrates. These findings suggest that lime and NaOH are more effective pretreatments for CC and SSB substrates. We used PRotein Interactive MOdeling (PRIMO) software to demonstrate that GH5D protein structure is an (α/β)8 barrel with a tunnel-like active site. Enzymes with this type of protein structure are able to perform transglycosylation, a process in which GH5D produced methyl, ethyl and propyl cellobiosides. We concluded that the GH5D, GH5E, GH5H and GH45 enzymes possess novel biochemical properties and that they form synergy during the hydrolysis of complex substrates (SSB and CC). GH5D transglycosylation could be used to produce novel biodegradable chemicals with special properties (e.g. anti-microbial properties). In conclusion, our findings suggest that GH5D, GH5E, GH5H and GH45 can potentially be used to improve biorefinery processes. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2019
- Full Text:
- Date Issued: 2019
- Authors: Mafa, Mpho Stephen
- Date: 2019
- Subjects: Termites , Metagenomics , Glucosides , Hydrolases , Enzymes , Feedstock
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/72414 , vital:30044 , DOI https://doi.org/10.21504/10962/72414
- Description: The current study investigated the biochemical properties of endo-glucanase (GH5E), exo-glucanase (GH5D), xylanase (GH5H) and endo-glucanase/xylanase (GH45), derived from the hindgut bacterial symbionts of a termite (Trinervitermes trinervoides) for their potential role in the biotechnology industry. All these enzymes, except GH5D, exhibited activities on cellulosic and xylan-rich polymeric substrates, which only displayed activity on p-nitrophenyl cellobioside. GH5D, GH5E, GH5H and GH45 enzymes retained more than 80% of their activities at pH 5.5 and also retained more than 80% of their activities at 40ºC. Furthermore, these enzymes were thermostable at 37ºC for 72 hours. GH5E, GH5H and GH45 were generally stable over a range of metal-ion. The kinetic parameters for GH5E were 5.68 mg/ml (KM) and 34.36 U/mg protein (Vmax). GH5D activity did not follow classical Michaelis-Menten kinetics, suggesting product inhibition. GH5H displayed KM values of 5.53, 95.03 and 2.10 mg/ml and Vmax values of 112.36, 144.45 and 180.32 U/mg protein on beechwood xylan, CMC, and xyloglucan, respectively. GH45 displayed a KM of 6.94 mg/ml and a Vmax of 12.30 U/mg protein on CMC. GH5D [cellobiohydrolase (CBH)] and a commercial CBHII (GH6) enzyme outperformed a commercial CBHI (GH7) enzyme when these enzymes hydrolysed β-glucan. GH5D and CBHII also displayed a higher degree of synergy on β-glucan but failed to show synergy on Avicel. We therefore concluded that GH5D and CBHII are β-glucan-specific cellobiohydrolases. The corncob (CC) and sweet sorghum bagasse (SSB) substrates were pretreated with lime, NaOH and NaClO2. Subsequent to pretreatment, these substrates were used to investigate if GH5D, GH5E, GH5H and GH45 could operate in synergy. Results revealed that out of 12 possible core enzyme sets constructed, only two (referred to as CES-E and CES-H) displayed higher activities on pretreated CC or SSB. Simultaneous synergy was generally the most effective mode of synergy during hydrolysis of alkaline pretreated SSB and CC samples by both CES-E and CES-H. Both core enzyme sets did not display synergy on oxidative pretreated substrates. These findings suggest that lime and NaOH are more effective pretreatments for CC and SSB substrates. We used PRotein Interactive MOdeling (PRIMO) software to demonstrate that GH5D protein structure is an (α/β)8 barrel with a tunnel-like active site. Enzymes with this type of protein structure are able to perform transglycosylation, a process in which GH5D produced methyl, ethyl and propyl cellobiosides. We concluded that the GH5D, GH5E, GH5H and GH45 enzymes possess novel biochemical properties and that they form synergy during the hydrolysis of complex substrates (SSB and CC). GH5D transglycosylation could be used to produce novel biodegradable chemicals with special properties (e.g. anti-microbial properties). In conclusion, our findings suggest that GH5D, GH5E, GH5H and GH45 can potentially be used to improve biorefinery processes. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2019
- Full Text:
- Date Issued: 2019
Characterization of the heat source of thermal aquifers within the Soutpansberg Basin in the Limpopo Province, South Africa: Evidence from geophysical and geological investigations
- Authors: Nyabeze, Peter Kushara
- Date: 2019
- Subjects: Basins (Geology) -- Analysis Geology, Structural -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: http://hdl.handle.net/10353/15167 , vital:40192
- Description: The research was conducted to contribute towards the knowledge base on the potential for geothermal energy in the Soutpansberg Basin, located in the Limpopo Province of South Africa. The focus area was Siloam, an area that hosts a hottest spring with the highest recorded temperature of 67.5°C. The research involved visits to the Soutpansberg Basin, water sampling, carrying out ground geophysical surveys, and high-level processing of airborne magnetic data to determine depths and temperatures of magnetic sources. The water samples from the hot springs were found to be enriched in sodium, bicarbonate and chlorine with very low concentrations of other element species. The chemical composition of the spring water indicated a source chemistry comprising of the Na-ClHCO3 water assemblage that is a typical signature for deep circulating groundwater of meteoric origin. The circulation depth was inferred to be 2.0 km. The increased resolution of the ground magnetic, electrical resistivity tomography, and electromagnetic conductivity methods data made it possible to delineate subsurface structures at the spring such as dykes, sills, faults and fractures from generated depth models. Modelling of ground magnetic data showed that the Siloam hot spring occurred between two interpreted north dipping dykes approximately 150 m apart. The minimum depth extent of the dykes was interpreted to be 650 m. The magnetic susceptibility values determined from rock measurements and modelling of magnetic data indicated the presence of volcanic and metamorphic rocks. Electromagnetic profiling data showed that there were three main high conductivity zones in the study area with values above 100 mS/m; A central zone associated with the spring; A zone to the south of the spring and a north zone associated with the Siloam Fault. Ground geophysics survey results confirmed the existence of the Siloam Fault. Two artesian boreholes with water warmer than 40 °C were identified to the south of the Siloam hot spring. Both electromagnetic conductivity and electrical resistivity tomography surveys delineated lateral and vertical variation in the bedrock to depths of 40 m to 60 m. Water bearing structures that could be faults, or fractures were identified. Layering due to weathering and water content was found to be in the depth range of 20 m to 40 m. The depths of the potential heat sources were computed from the radially averaged power spectrum of airborne magnetic data for square blocks with side dimensions L of 51 km, 103 km, and 129 km. Spectral analysis based approaches namely Centroid method, Spectral peak method, and the Fractal based approach were used for computing depth and temperatures to heat sources. Airborne magnetic data sets with larger window sizes were preferred for depth computations, as they preserved spectral signatures of deeper sources and reduced the contribution of shallower sources. The size of the data windows did not have a marked effect of depth and temperature values. Shallower magnetic sources depths of approximately 2.0 km were delineated using the Euler deconvolution method. An anticlinal feature at depths of 2.0 to 4.5 km was 4 Final Submission of Thesis, Dissertation or Research Report/Project, Conference or Exam Paper delineated in the central part of the basin. Spectral analysis results indicated that the depth to the top of magnetic sources was at 3.5 km to 6.2 km; the centroid of the basement at 7.92 km to 13.41 km, and the basal below 11.09 km and 14.08 km. The lower end depth spectrum was determined from application of the Centroid method with the deeper being results from the Fractal based approach. The Spectral peak method was useful for determining the depth to the top of magnetic sources. The temperature of the top of magnetic sources and basement centroid were computed to be in the range 234.00 °C to 281.34 °C. Magnetic source depths and basal temperatures that were in the Curie point range within which rocks lose magnetism due to heat were determined, using a computation approach that utilised fractal parameters, to be 21.39 km and 577.42 °C, respectively. Increasing the value of the fractal parameter β from 0 to 4, had an effect of retaining deeper depths and higher temperatures. The fractal parameter β range of 3 to 4 that gave the Curie point parameters indicated basal rock types with an igneous predisposition. The research highlighted evidence for the existence of the Soutpansberg Basin Geothermal Field (SBGF). The area around Siloam is a potential target for drilling exploration geothermal energy boreholes based on the occurrence of hot springs, shallow heat source depths, anticlinal structure, high formation temperatures, deep circulating water and the achieved Curie point temperature.
- Full Text:
- Date Issued: 2019
- Authors: Nyabeze, Peter Kushara
- Date: 2019
- Subjects: Basins (Geology) -- Analysis Geology, Structural -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: http://hdl.handle.net/10353/15167 , vital:40192
- Description: The research was conducted to contribute towards the knowledge base on the potential for geothermal energy in the Soutpansberg Basin, located in the Limpopo Province of South Africa. The focus area was Siloam, an area that hosts a hottest spring with the highest recorded temperature of 67.5°C. The research involved visits to the Soutpansberg Basin, water sampling, carrying out ground geophysical surveys, and high-level processing of airborne magnetic data to determine depths and temperatures of magnetic sources. The water samples from the hot springs were found to be enriched in sodium, bicarbonate and chlorine with very low concentrations of other element species. The chemical composition of the spring water indicated a source chemistry comprising of the Na-ClHCO3 water assemblage that is a typical signature for deep circulating groundwater of meteoric origin. The circulation depth was inferred to be 2.0 km. The increased resolution of the ground magnetic, electrical resistivity tomography, and electromagnetic conductivity methods data made it possible to delineate subsurface structures at the spring such as dykes, sills, faults and fractures from generated depth models. Modelling of ground magnetic data showed that the Siloam hot spring occurred between two interpreted north dipping dykes approximately 150 m apart. The minimum depth extent of the dykes was interpreted to be 650 m. The magnetic susceptibility values determined from rock measurements and modelling of magnetic data indicated the presence of volcanic and metamorphic rocks. Electromagnetic profiling data showed that there were three main high conductivity zones in the study area with values above 100 mS/m; A central zone associated with the spring; A zone to the south of the spring and a north zone associated with the Siloam Fault. Ground geophysics survey results confirmed the existence of the Siloam Fault. Two artesian boreholes with water warmer than 40 °C were identified to the south of the Siloam hot spring. Both electromagnetic conductivity and electrical resistivity tomography surveys delineated lateral and vertical variation in the bedrock to depths of 40 m to 60 m. Water bearing structures that could be faults, or fractures were identified. Layering due to weathering and water content was found to be in the depth range of 20 m to 40 m. The depths of the potential heat sources were computed from the radially averaged power spectrum of airborne magnetic data for square blocks with side dimensions L of 51 km, 103 km, and 129 km. Spectral analysis based approaches namely Centroid method, Spectral peak method, and the Fractal based approach were used for computing depth and temperatures to heat sources. Airborne magnetic data sets with larger window sizes were preferred for depth computations, as they preserved spectral signatures of deeper sources and reduced the contribution of shallower sources. The size of the data windows did not have a marked effect of depth and temperature values. Shallower magnetic sources depths of approximately 2.0 km were delineated using the Euler deconvolution method. An anticlinal feature at depths of 2.0 to 4.5 km was 4 Final Submission of Thesis, Dissertation or Research Report/Project, Conference or Exam Paper delineated in the central part of the basin. Spectral analysis results indicated that the depth to the top of magnetic sources was at 3.5 km to 6.2 km; the centroid of the basement at 7.92 km to 13.41 km, and the basal below 11.09 km and 14.08 km. The lower end depth spectrum was determined from application of the Centroid method with the deeper being results from the Fractal based approach. The Spectral peak method was useful for determining the depth to the top of magnetic sources. The temperature of the top of magnetic sources and basement centroid were computed to be in the range 234.00 °C to 281.34 °C. Magnetic source depths and basal temperatures that were in the Curie point range within which rocks lose magnetism due to heat were determined, using a computation approach that utilised fractal parameters, to be 21.39 km and 577.42 °C, respectively. Increasing the value of the fractal parameter β from 0 to 4, had an effect of retaining deeper depths and higher temperatures. The fractal parameter β range of 3 to 4 that gave the Curie point parameters indicated basal rock types with an igneous predisposition. The research highlighted evidence for the existence of the Soutpansberg Basin Geothermal Field (SBGF). The area around Siloam is a potential target for drilling exploration geothermal energy boreholes based on the occurrence of hot springs, shallow heat source depths, anticlinal structure, high formation temperatures, deep circulating water and the achieved Curie point temperature.
- Full Text:
- Date Issued: 2019
Charting freedom: inequality beliefs, preferences for redistribution, and distributive social policy in contemporary South Africa
- Authors: Roberts, Benjamin J
- Date: 2019
- Subjects: South Africa -- Economic conditions South Africa -- Economic policy South Africa -- Social policy , Democracy -- Economic conditions -- South Africa Race discrimination -- South Africa Poverty -- South Africa Equality -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64999 , vital:28644
- Description: While the transition to democracy in South Africa extended civil and political rights and freedoms to all South Africans, there has been disagreement over the preferred nature and scope of social rights within post-apartheid society, reflecting debates over the trajectory of economic policy. Appreciable developmental gains have been made by the state over the last quarter-century, yet the challenges of poverty, unemployment and inequality persist, coupled with mounting popular discontent with the pace of transformation and political accountability. This has led to fundamental questions about social justice, restitution, and the kind of society we wish to promote. Appeals for a more inclusive, transformative social policy have also emerged, arguing that a wider vision of society is required involving multiple government responsibilities and informed by an ethic of equality and social solidarity. Against this background, in this thesis I study the views of the South African public towards economic inequality, general preferences for government-led redistribution, as well as support for social policies intended to promote racial and economic transformation. The research has been guided by several overarching questions: To what extent do South Africans share common general beliefs about material inequality? Does the public exhibit a preference for government redistribution in principle? And how unified or polarised are South Africans in their support for specific redress policies in the country? Responding to these questions has been achieved by drawing on unique, nationally representative data from the South African Social Attitudes Survey (SASAS), which has enabled me to chart social attitudes over a period of almost fifteen years between late 2003 and early 2017. Use has also been made of social citizenship as a guiding conceptual framework to understanding social policy predispositions and analysing attitudinal change. The results demonstrate that the public is united in its awareness of and deep concern about economic inequality. Since the early 2000s, a significant majority has consistently expressed the view that the income gap in the country is too large, articulated a strong preference for a more equitable social structure, and acknowledged the class and social tensions that economic inequality has produced. There is also a preference for a narrowing of earnings disparities, a more generous minimum wage, and regulatory limits on executive pay. While this suggests a desire for fair and legitimate remuneration, the analysis also reveals that South Africans are willing to tolerate fairly high levels of inequality. Nonetheless, these beliefs are generally interpreted as a desire for a more equitable and fair society. This preference for change is reflected in a fairly strong belief that government should assume responsibility for reducing material disparities. One’s social position, mobility history, awareness of inequality, political leaning and racial attitudes all have a bearing on how weak and strong this predisposition is, but the normative demand for political redistribution remains fairly widely shared irrespective of these individual traits. Greater polarisation is however evident with respect to redistributive social policy, especially measures designed to overcome historical racial injustice (affirmative action, sports quotas, and land reform). These intergroup differences converge considerably when referring to class-based policy measures. One surprising finding is the evidence that South Africa’s youngest generation, the so-called ‘Born Frees’, tend to adopt a similar predisposition to redress policy as older generations, thus confounding expectations of a post-apartheid value change. I conclude by arguing that there seems to be a firmer basis for a social compact about preferences for interventions designed to produce a more just society than is typically assumed. Intractably high levels of economic inequality during the country’s first quarter-century of democracy is resulting in a growing recognition of the need for a stronger policy emphasis on economic inequality in South Africa over coming decades if the vision enshrined in the Freedom Charter and the Constitution is to be realised. South Africans may not be able to fully agree about the specific elements that constitute a socially just response to economic inequality. Yet, the common identification of and concern with redressable injustice, coupled with a broad-based commitment to government redistribution and classbased social policies, could serve as a foundation on which to rekindle the solidaristic spirit of 1994 and forge progress towards a more equitable society.
- Full Text:
- Date Issued: 2019
- Authors: Roberts, Benjamin J
- Date: 2019
- Subjects: South Africa -- Economic conditions South Africa -- Economic policy South Africa -- Social policy , Democracy -- Economic conditions -- South Africa Race discrimination -- South Africa Poverty -- South Africa Equality -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64999 , vital:28644
- Description: While the transition to democracy in South Africa extended civil and political rights and freedoms to all South Africans, there has been disagreement over the preferred nature and scope of social rights within post-apartheid society, reflecting debates over the trajectory of economic policy. Appreciable developmental gains have been made by the state over the last quarter-century, yet the challenges of poverty, unemployment and inequality persist, coupled with mounting popular discontent with the pace of transformation and political accountability. This has led to fundamental questions about social justice, restitution, and the kind of society we wish to promote. Appeals for a more inclusive, transformative social policy have also emerged, arguing that a wider vision of society is required involving multiple government responsibilities and informed by an ethic of equality and social solidarity. Against this background, in this thesis I study the views of the South African public towards economic inequality, general preferences for government-led redistribution, as well as support for social policies intended to promote racial and economic transformation. The research has been guided by several overarching questions: To what extent do South Africans share common general beliefs about material inequality? Does the public exhibit a preference for government redistribution in principle? And how unified or polarised are South Africans in their support for specific redress policies in the country? Responding to these questions has been achieved by drawing on unique, nationally representative data from the South African Social Attitudes Survey (SASAS), which has enabled me to chart social attitudes over a period of almost fifteen years between late 2003 and early 2017. Use has also been made of social citizenship as a guiding conceptual framework to understanding social policy predispositions and analysing attitudinal change. The results demonstrate that the public is united in its awareness of and deep concern about economic inequality. Since the early 2000s, a significant majority has consistently expressed the view that the income gap in the country is too large, articulated a strong preference for a more equitable social structure, and acknowledged the class and social tensions that economic inequality has produced. There is also a preference for a narrowing of earnings disparities, a more generous minimum wage, and regulatory limits on executive pay. While this suggests a desire for fair and legitimate remuneration, the analysis also reveals that South Africans are willing to tolerate fairly high levels of inequality. Nonetheless, these beliefs are generally interpreted as a desire for a more equitable and fair society. This preference for change is reflected in a fairly strong belief that government should assume responsibility for reducing material disparities. One’s social position, mobility history, awareness of inequality, political leaning and racial attitudes all have a bearing on how weak and strong this predisposition is, but the normative demand for political redistribution remains fairly widely shared irrespective of these individual traits. Greater polarisation is however evident with respect to redistributive social policy, especially measures designed to overcome historical racial injustice (affirmative action, sports quotas, and land reform). These intergroup differences converge considerably when referring to class-based policy measures. One surprising finding is the evidence that South Africa’s youngest generation, the so-called ‘Born Frees’, tend to adopt a similar predisposition to redress policy as older generations, thus confounding expectations of a post-apartheid value change. I conclude by arguing that there seems to be a firmer basis for a social compact about preferences for interventions designed to produce a more just society than is typically assumed. Intractably high levels of economic inequality during the country’s first quarter-century of democracy is resulting in a growing recognition of the need for a stronger policy emphasis on economic inequality in South Africa over coming decades if the vision enshrined in the Freedom Charter and the Constitution is to be realised. South Africans may not be able to fully agree about the specific elements that constitute a socially just response to economic inequality. Yet, the common identification of and concern with redressable injustice, coupled with a broad-based commitment to government redistribution and classbased social policies, could serve as a foundation on which to rekindle the solidaristic spirit of 1994 and forge progress towards a more equitable society.
- Full Text:
- Date Issued: 2019
Checklist, endemism, English vernacular names and identification of the cicadas (Insecta, Hemiptera, Cicadidae) of KwaZulu-Natal, South Africa:
- Armstrong, Adrian J, Villet, Martin H
- Authors: Armstrong, Adrian J , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140586 , vital:37901 , DOI: 10.3897/afrinvertebr.60.35130
- Description: Public understanding of the goals of applied biology and conservation is promoted by showcasing charismatic or significant organisms using vernacular names. Conservation activities in the province of KwaZulu-Natal, South Africa, are prioritising taxa that have high rates of provincial endemism, such as snails, earthworms, millipedes and cicadas. To assist wider public engagement in these activities, an assessment of endemism of the cicadas of KwaZulu-Natal is presented along with a dichotomous, 37-couplet key for the identification of males, based mainly on externally visible morphology and colouration. Standardised English vernacular names coined following a simple naming convention are proposed. Forty-two percent (16 out of 38) of the cicada species known from KwaZulu-Natal are endemic to the province. Photographs of some of the species are included to facilitate their identification. Photographs can be used for identification of various species providing that the diagnostic characters are visible in the photographs. For this purpose, photographs may have to be taken of hand-held individuals. Some of the endemic species are of particular concern for conservation because they are not known to occur in statutory protected areas or are only known from relatively small protected areas. The latter may not be able to ensure the long-term survival of the species. The rate and extent of loss of habitat outside protected areas is likely to be a grave threat to species that are not protected or that are inadequately conserved in statutory protected areas. The standardised vernacular names proposed here provide a tool for communicating provincial conservation plans and concerns with stakeholders in KwaZulu-Natal and for stimulating interest in cicadas amongst land users, environmental impact assessment practitioners, biologists, naturalists and citizen scientists.
- Full Text:
- Date Issued: 2019
- Authors: Armstrong, Adrian J , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140586 , vital:37901 , DOI: 10.3897/afrinvertebr.60.35130
- Description: Public understanding of the goals of applied biology and conservation is promoted by showcasing charismatic or significant organisms using vernacular names. Conservation activities in the province of KwaZulu-Natal, South Africa, are prioritising taxa that have high rates of provincial endemism, such as snails, earthworms, millipedes and cicadas. To assist wider public engagement in these activities, an assessment of endemism of the cicadas of KwaZulu-Natal is presented along with a dichotomous, 37-couplet key for the identification of males, based mainly on externally visible morphology and colouration. Standardised English vernacular names coined following a simple naming convention are proposed. Forty-two percent (16 out of 38) of the cicada species known from KwaZulu-Natal are endemic to the province. Photographs of some of the species are included to facilitate their identification. Photographs can be used for identification of various species providing that the diagnostic characters are visible in the photographs. For this purpose, photographs may have to be taken of hand-held individuals. Some of the endemic species are of particular concern for conservation because they are not known to occur in statutory protected areas or are only known from relatively small protected areas. The latter may not be able to ensure the long-term survival of the species. The rate and extent of loss of habitat outside protected areas is likely to be a grave threat to species that are not protected or that are inadequately conserved in statutory protected areas. The standardised vernacular names proposed here provide a tool for communicating provincial conservation plans and concerns with stakeholders in KwaZulu-Natal and for stimulating interest in cicadas amongst land users, environmental impact assessment practitioners, biologists, naturalists and citizen scientists.
- Full Text:
- Date Issued: 2019
Cheetah Acinonyx jubatus behaviour and resource use in response to other African large carnivores
- Authors: Cornhill, Kristina
- Date: 2019
- Subjects: Cheetahs -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44735 , vital:38169
- Description: Competition occurs between species for shared resources. Subordinate species employ resource selection to shift their resource use away from that of dominant species in order to avoid the negative consequences of competition. Only in Africa is the post-Pleistocene large carnivore guild intact, consisting of lions Panthera leo, spotted hyaenas Crocuta crocuta, leopards Panthera pardus, cheetahs Acinonyx jubatus, and African wild dogs Lycaon pictus. Therefore, only in Africa can we explore how large carnivores co-exist with one another in a diverse community. Cheetahs are a subordinate member of the large carnivore guild due to their small stature and solitary nature. However, we still do not fully understand how competition shapes cheetah behaviour and resource use. I used cheetahs as a model subordinate predator to determine the behavioural responses and resource selection of cheetah in response to assumed competition from other large carnivores. I experimentally explored the behavioural response of cheetah to large carnivore scent sources (scats) and their presence at cheetah scent-marking sites to test for avoidance of such cues. Moreover, using unplanned experiments based on the resource use of cheetahs in the absence and then presence of lions (assessing space and time use by cheetah) and African wild dogs (assessing prey use by both species), I evaluated resource selection by cheetahs as a way to reduce competition with these large carnivores. In addition, I measured spatial and temporal partitioning between cheetahs and all four large carnivores at camera trap sites. Finally, I assessed whether cheetahs responded to competitors using a long term proactive response or a short term reactive response. I found that all four of the other large carnivores in the guild shaped cheetahs resource use, however, all did so on different axes in accordance with the niche complementarity hypothesis. Lions and spotted hyenas were avoided through time, African wild dogs through space and prey use, and lions and leopards on the spatiotemporal axis. Moreover, I show that cheetahs utilize a reactive response to competition that allows them to avoid risk while still obtaining necessary resources.
- Full Text:
- Date Issued: 2019
- Authors: Cornhill, Kristina
- Date: 2019
- Subjects: Cheetahs -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44735 , vital:38169
- Description: Competition occurs between species for shared resources. Subordinate species employ resource selection to shift their resource use away from that of dominant species in order to avoid the negative consequences of competition. Only in Africa is the post-Pleistocene large carnivore guild intact, consisting of lions Panthera leo, spotted hyaenas Crocuta crocuta, leopards Panthera pardus, cheetahs Acinonyx jubatus, and African wild dogs Lycaon pictus. Therefore, only in Africa can we explore how large carnivores co-exist with one another in a diverse community. Cheetahs are a subordinate member of the large carnivore guild due to their small stature and solitary nature. However, we still do not fully understand how competition shapes cheetah behaviour and resource use. I used cheetahs as a model subordinate predator to determine the behavioural responses and resource selection of cheetah in response to assumed competition from other large carnivores. I experimentally explored the behavioural response of cheetah to large carnivore scent sources (scats) and their presence at cheetah scent-marking sites to test for avoidance of such cues. Moreover, using unplanned experiments based on the resource use of cheetahs in the absence and then presence of lions (assessing space and time use by cheetah) and African wild dogs (assessing prey use by both species), I evaluated resource selection by cheetahs as a way to reduce competition with these large carnivores. In addition, I measured spatial and temporal partitioning between cheetahs and all four large carnivores at camera trap sites. Finally, I assessed whether cheetahs responded to competitors using a long term proactive response or a short term reactive response. I found that all four of the other large carnivores in the guild shaped cheetahs resource use, however, all did so on different axes in accordance with the niche complementarity hypothesis. Lions and spotted hyenas were avoided through time, African wild dogs through space and prey use, and lions and leopards on the spatiotemporal axis. Moreover, I show that cheetahs utilize a reactive response to competition that allows them to avoid risk while still obtaining necessary resources.
- Full Text:
- Date Issued: 2019
Chinese engagement of Zimbabwe and the limits of elite agency:
- Chipaike, Ronald, Bischoff, Paul, 1954-
- Authors: Chipaike, Ronald , Bischoff, Paul, 1954-
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161548 , vital:40637 , https://0-doi.org.wam.seals.ac.za/10.1177/0021909619848783
- Description: This article contends that Zimbabwe’s agency in its engagement with China has been limited and at best circumscribed. This owes to factors such as indifference by state authorities to cooperation with civil society actors in negotiating with Chinese actors, the desperation of the The Zimbabwe African National Union – Patriotic Front regime in the face of isolation by erstwhile partners as well as the opacity and secrecy that characterizes significant areas of the Zimbabwe–China relationship. The pressing need for critical institutions such as parliament to play independent oversight roles as well as the creation of space for civil society watchdog functions are highlighted as key enablers if Zimbabwean agency is to generate positive gains from the country’s engagement with China.
- Full Text:
- Date Issued: 2019
- Authors: Chipaike, Ronald , Bischoff, Paul, 1954-
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161548 , vital:40637 , https://0-doi.org.wam.seals.ac.za/10.1177/0021909619848783
- Description: This article contends that Zimbabwe’s agency in its engagement with China has been limited and at best circumscribed. This owes to factors such as indifference by state authorities to cooperation with civil society actors in negotiating with Chinese actors, the desperation of the The Zimbabwe African National Union – Patriotic Front regime in the face of isolation by erstwhile partners as well as the opacity and secrecy that characterizes significant areas of the Zimbabwe–China relationship. The pressing need for critical institutions such as parliament to play independent oversight roles as well as the creation of space for civil society watchdog functions are highlighted as key enablers if Zimbabwean agency is to generate positive gains from the country’s engagement with China.
- Full Text:
- Date Issued: 2019
Chiral Modulation from Molecular to Macroscopic levels by synthetic chiral-amide-bonded porphyrin dimers
- Liang, Xu, Qin, Mingfeng, Zhang, Xiaomei, Mack, John, Soy, Rodah, Nyokong, Tebello, Zhu, Weihua
- Authors: Liang, Xu , Qin, Mingfeng , Zhang, Xiaomei , Mack, John , Soy, Rodah , Nyokong, Tebello , Zhu, Weihua
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186802 , vital:44535 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107637"
- Description: Six different nanoarchitectures were constructed by a series of synthetic bio-inspired chiral porphyrin dimers through molecular self-assembly behaviour. A plausible mechanism of chiral expression from the molecular to the macroscopic levels was investigated through an analysis of the optical spectroscopy and theoretical calculations.
- Full Text:
- Date Issued: 2019
- Authors: Liang, Xu , Qin, Mingfeng , Zhang, Xiaomei , Mack, John , Soy, Rodah , Nyokong, Tebello , Zhu, Weihua
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186802 , vital:44535 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107637"
- Description: Six different nanoarchitectures were constructed by a series of synthetic bio-inspired chiral porphyrin dimers through molecular self-assembly behaviour. A plausible mechanism of chiral expression from the molecular to the macroscopic levels was investigated through an analysis of the optical spectroscopy and theoretical calculations.
- Full Text:
- Date Issued: 2019
Chitin hydrolysis with chitinolytic enzymes for the production of chitooligomers with antimicrobial properties
- Authors: Oree, Glynis
- Date: 2019
- Subjects: Chitin -- Biotechnology , Enzymes -- Biotechnology , Hydrolysis , Chitooligomers -- Biotechnology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67887 , vital:29165
- Description: There are many diseases and illnesses in the world that require new drug treatments and chitin has been shown to produce chitooligomeric derivatives which exhibit promising antimicrobial and immune-enhancing properties. However, the rate-limiting step is associated with the high recalcitrance of chitinous substrates, and low hydrolytic activities of chitinolytic enzymes, resulting in low product release. To improve and create a more sustainable and economical process, enhancing chitin hydrolysis through various treatment procedures is essential for obtaining high enzyme hydrolysis rates, resulting in a higher yield of chitooligomers (CHOS). In literature, pre-treatment of insoluble biomass is generally associated with an increase in accessibility of the carbohydrate to hydrolytic enzymes, thus generating more products. The first part of this study investigated the effect of alkali- (NaOH) and acid pre-treatments (HCl and phosphoric acid) on chitin biomass, and chemical and morphological modifications were assessed by the employment of scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Energy-Dispersive X-ray spectrometery (EDX) and x-ray diffraction (XRD). Data obtained confirmed that pre-treated substrates were more chemically and morphologically modified. These results confirmed the fact that pre-treatment of chitin disrupts the structure of the biomass, rendering the polymer more accessible for enzymatic hydrolysis. The commercial chitinases from Bacillus cereus and Streptomyces griseus (CHB and CHS) are costly. Bio-prospecting for other chitin-degrading enzymes from alternate sources such as Oidiodendron maius, or the recombinant expression of CHOS, was a more economically feasible avenue. The chit1 gene from Thermomyces lanuginosus, expressed in Pichia pastoris, produced a large range CHOS with a degree of polymerisation (DP) ranging from 1 to above 6. TLC analysis showed that O. maius exhibited chitin-degrading properties by producing CHOS with a DP length of 1 to 3. These two sources were therefore successful in producing chitin-degrading enzymes. The physico-chemical properties of commercial (CHB and CHS) and expressed (Chit1) chitinolytic enzymes were investigated, to determine under which biochemical conditions and on which type of biomass they can function on optimally, for the production of value-added products such as CHOS. Substrate affinity assays were conducted on the un-treated and pre-treated biomass. TLC revealed that chitosan hydrolysis by the commercial chitinases produced the largest range of CHOS with a DP length ranging from 1 to 6. A range of temperatures (35-90oC) were investigated and CHB, CHS and Chit1 displayed optimum activities at 50, 40 and 45 oC, respectively. Thermostability studies that were conducted at 37 and 50oC revealed that CHB and CHS were most stable at 37oC. Chit1 showed great thermostablity at both temperatures, rendering this enzyme suitable for industrial processes at high temperatures. pH optima studies demonstrated that the pH optima for CHB, CHS and Chit1 was at a pH of 5.0, with specific activities of 33.459, 46.2 and 5.776 μmol/h/mg, respectively. The chain cleaving patterns of the commercial enzymes were determined and exo-chitinase activity was exhibited, due to the production of CHOS that were predominantly of a DP length of 2. Enzyme binary synergy studies were conducted with commercial chitinases (CHB and CHS) on colloidal chitin. Studies illustrated that the simultaneous combination of CHB 75%: CHS 25% produced the highest specific activity (3.526 μmol/h/mg), with no synergy. TLC analysis of this enzyme combination over time revealed that predominantly chitobiose was produced. This suggested that the substrate crystallinity and morphology played an important role in the way the enzymes cleaved the carbohydrate. Since CHOS have shown great promise for their antimicrobial properties, the CHOS generated from the chitinous substrates were tested for antimicrobial properties on Bacillus subtilis, Escherichia coli, Klebsiella and Staphlococcus aureus. This study revealed that certain CHOS produced have inhibitory effects on certain bacteria and could potentially be used in the pharamceutical or medical industries. In conclusion, this study revealed that chitinases can be produced and found in alternate sources and be used for the hydrolysis of chitinous biomass in a more sustainabe and economically viable manner. The chitinases investigated (CHB, CHS and Chit1) exhibited different cleaving patterns of the chitinous substrates due to the chemical and morphological properties of the biomass. CHOS produced from chitinous biomass exhibited some inhibitory effects on bacterial growth and show potential for use in the medical industry.
- Full Text:
- Date Issued: 2019
- Authors: Oree, Glynis
- Date: 2019
- Subjects: Chitin -- Biotechnology , Enzymes -- Biotechnology , Hydrolysis , Chitooligomers -- Biotechnology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67887 , vital:29165
- Description: There are many diseases and illnesses in the world that require new drug treatments and chitin has been shown to produce chitooligomeric derivatives which exhibit promising antimicrobial and immune-enhancing properties. However, the rate-limiting step is associated with the high recalcitrance of chitinous substrates, and low hydrolytic activities of chitinolytic enzymes, resulting in low product release. To improve and create a more sustainable and economical process, enhancing chitin hydrolysis through various treatment procedures is essential for obtaining high enzyme hydrolysis rates, resulting in a higher yield of chitooligomers (CHOS). In literature, pre-treatment of insoluble biomass is generally associated with an increase in accessibility of the carbohydrate to hydrolytic enzymes, thus generating more products. The first part of this study investigated the effect of alkali- (NaOH) and acid pre-treatments (HCl and phosphoric acid) on chitin biomass, and chemical and morphological modifications were assessed by the employment of scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Energy-Dispersive X-ray spectrometery (EDX) and x-ray diffraction (XRD). Data obtained confirmed that pre-treated substrates were more chemically and morphologically modified. These results confirmed the fact that pre-treatment of chitin disrupts the structure of the biomass, rendering the polymer more accessible for enzymatic hydrolysis. The commercial chitinases from Bacillus cereus and Streptomyces griseus (CHB and CHS) are costly. Bio-prospecting for other chitin-degrading enzymes from alternate sources such as Oidiodendron maius, or the recombinant expression of CHOS, was a more economically feasible avenue. The chit1 gene from Thermomyces lanuginosus, expressed in Pichia pastoris, produced a large range CHOS with a degree of polymerisation (DP) ranging from 1 to above 6. TLC analysis showed that O. maius exhibited chitin-degrading properties by producing CHOS with a DP length of 1 to 3. These two sources were therefore successful in producing chitin-degrading enzymes. The physico-chemical properties of commercial (CHB and CHS) and expressed (Chit1) chitinolytic enzymes were investigated, to determine under which biochemical conditions and on which type of biomass they can function on optimally, for the production of value-added products such as CHOS. Substrate affinity assays were conducted on the un-treated and pre-treated biomass. TLC revealed that chitosan hydrolysis by the commercial chitinases produced the largest range of CHOS with a DP length ranging from 1 to 6. A range of temperatures (35-90oC) were investigated and CHB, CHS and Chit1 displayed optimum activities at 50, 40 and 45 oC, respectively. Thermostability studies that were conducted at 37 and 50oC revealed that CHB and CHS were most stable at 37oC. Chit1 showed great thermostablity at both temperatures, rendering this enzyme suitable for industrial processes at high temperatures. pH optima studies demonstrated that the pH optima for CHB, CHS and Chit1 was at a pH of 5.0, with specific activities of 33.459, 46.2 and 5.776 μmol/h/mg, respectively. The chain cleaving patterns of the commercial enzymes were determined and exo-chitinase activity was exhibited, due to the production of CHOS that were predominantly of a DP length of 2. Enzyme binary synergy studies were conducted with commercial chitinases (CHB and CHS) on colloidal chitin. Studies illustrated that the simultaneous combination of CHB 75%: CHS 25% produced the highest specific activity (3.526 μmol/h/mg), with no synergy. TLC analysis of this enzyme combination over time revealed that predominantly chitobiose was produced. This suggested that the substrate crystallinity and morphology played an important role in the way the enzymes cleaved the carbohydrate. Since CHOS have shown great promise for their antimicrobial properties, the CHOS generated from the chitinous substrates were tested for antimicrobial properties on Bacillus subtilis, Escherichia coli, Klebsiella and Staphlococcus aureus. This study revealed that certain CHOS produced have inhibitory effects on certain bacteria and could potentially be used in the pharamceutical or medical industries. In conclusion, this study revealed that chitinases can be produced and found in alternate sources and be used for the hydrolysis of chitinous biomass in a more sustainabe and economically viable manner. The chitinases investigated (CHB, CHS and Chit1) exhibited different cleaving patterns of the chitinous substrates due to the chemical and morphological properties of the biomass. CHOS produced from chitinous biomass exhibited some inhibitory effects on bacterial growth and show potential for use in the medical industry.
- Full Text:
- Date Issued: 2019
Chlorophyll fluorometry as a method of determining the effectiveness of a biological control agent in post-release evaluations
- Miller, Benjamin E, Coetzee, Julie A, Hill, Martin P
- Authors: Miller, Benjamin E , Coetzee, Julie A , Hill, Martin P
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417438 , vital:71453 , xlink:href="https://doi.org/10.1080/09583157.2019.1656165"
- Description: The impact of the planthopper Megamelus scutellaris, a biocontrol agent of water hyacinth in South Africa, was assessed using chlorophyll fluorometry in a greenhouse study under two different eutrophic nutrient treatments and agent densities (high and low). The results indicated that plants grown in low nutrients with high densities of M. scutellaris showed the greatest reduction in the fluorescence parameters Fv/Fm and PIabs. The successful use of chlorophyll fluorometry for the detection of subtle insect damage to water hyacinth leaves could have future application in post-release studies to measure the impact of M. scutellaris in the field.
- Full Text:
- Date Issued: 2019
- Authors: Miller, Benjamin E , Coetzee, Julie A , Hill, Martin P
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417438 , vital:71453 , xlink:href="https://doi.org/10.1080/09583157.2019.1656165"
- Description: The impact of the planthopper Megamelus scutellaris, a biocontrol agent of water hyacinth in South Africa, was assessed using chlorophyll fluorometry in a greenhouse study under two different eutrophic nutrient treatments and agent densities (high and low). The results indicated that plants grown in low nutrients with high densities of M. scutellaris showed the greatest reduction in the fluorescence parameters Fv/Fm and PIabs. The successful use of chlorophyll fluorometry for the detection of subtle insect damage to water hyacinth leaves could have future application in post-release studies to measure the impact of M. scutellaris in the field.
- Full Text:
- Date Issued: 2019
Civil society engagement with water governance at a local government scale in South Africa
- Weaver, Matthew James Thanduxolo
- Authors: Weaver, Matthew James Thanduxolo
- Date: 2019
- Subjects: Government accountability -- South Africa , Civil Society -- South Africa , Political participation -- South Africa , Local government -- South Africa , Water supply -- Management , Water resources development -- South Africa , Water quality management -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/151316 , vital:39051
- Description: The South African state’s ideological commitment to a participatory approach to managing water resources and delivering services in a way that includes all stakeholders warrants critical analysis.Realising this ideological commitment has proved challenging, due largely to the complex historical, political, social, and environmental context of integrated water resource management (IWRM) in South Africa. The overarching aim of this study was to explore and expand the learning of civil societyparticipating in water governance processes at a local government scale. To address this aim a single, in-depth, four-year case study into civil society participation in water governance in the Makana Local Municipality in the Eastern Cape Province of South Africa was conducted between 2014 and 2018. The case study comprised two research phases. Both phases of the research were conducted using an adaptive transdisciplinary and participatory action research approach underpinned by General Complexity Theory. Located at the research-practice interface, the study sought to be transformative and advance both scientific research and societal goals. Qualitative research methods and inductive and deductive modes of inference were used to collect and analyse the data respectively. In the first phase of the study, a Communities of Practice theoretical framing was adopted to investigate the emergence, practice and learning of a civil society organisation (CSO), Water for Dignity (WfD), in response to household water service delivery issues in the municipality. This phase served to build an understanding of factors that enabled and constrained the practice of WfD in addressing local water service issues, and of their role as social learning agents in building water-related knowledge in their community. As participation with the first civil society organisation fragmented, the opportunity arose for local government, the National Department of Water and Sanitation and civil society to co-engage. This opened up the second phase of the research during which the role of a multi-stakeholder platform, the Makana Water Forum (MWF), in enabling democratic water governance was investigated. The MWF was South Africa’s first catchment management forum with an integrated water service and water resource management agenda. In this phase, the study drew on interventionist methodology, Change Laboratory, from Cultural Historical Activity Theory (CHAT) to 1) describe the historical development, composition and shared purpose of the MWF multi-activity system constellation; and to 2) guide participants through seven learning actions (expansive learning cycle) to identify, analyse, model and implement remedial actions to problematic aspects (contradictions) of the MWF practice. Participants of the Change Laboratory workshops built their individual and collective transformative agency (deliberate actions to transform a problematic situation) as they navigated the expansive learning process. The development of this agency was identified through a micro-analysis of agentive talk. The two phases served to advance the exploration of civil society participation from informal participation to address water issues, to formal participation in water governance processes at a local government scale. Findings from the first phase of the research revealed that dedicated and sustained support of partners with distributed expertise and the highly motivated core members of WfD enabled the practice and emergence of the civil society organisation. However, factors such as poor internal leadership, power dynamics between supporting partners, socio-economic constraints and a deeply embedded lack of agency were found to be key constraining factors to WfD’s practice. Findings revealed that learning at WfD team level occurred in four ways, through learning as belonging, learning as doing, learning as experiencing and learning as becoming. The WfD CSO was able to catalyse social learning related to personal water rights; and best practices for improving water quality and water conservation in their wider community of practice. Social learning was fostered mainly through structured citizen engagements offered by WfD. The research provides evidence that civil society organisations can play an important role in bridging water-related knowledge gaps and can foster active citizenship in South African communities. However, despite significant inputs of support and resources through the engaged transdisciplinary research process, the practice and learning outcomes of WfD had a marginal transformative impact on improving the citizen’s every-day water service experiences. Findings from the second phase of the study revealed the MWF to resemble a multi-activity system constellation with a multiple, partially overlapping. interests related to the management of water. The establishment, function and contradictions constraining the function of the MWF were influenced by past cycles of participatory water governance-related activity and practice at national and local scales. Through the Change Laboratory process, 25 contradictions were identified that appeared to constrain the ability of the MWF to enable inclusive and meaningful participatory water governance. Through a process of expansive learning, participants sought to overcome three sets of contradictions grouped as Problem Themes: lack of clear focus of the MWF; representation, representivity and nonattendance; and the MWF relationship with the Makana Local Municipality. Remedial actions modelled and those enacted have improved aspects of the function of the MWF (such as diversified modes of engagement and a more focussed agenda) but have only resulted in incremental shifts towards enabling improved participatory practice, most markedly in building a collaborative relationship and trust between the MWF members, municipal and government officials. The microanalysis of agentive talk revealed seven different expressions of transformative agency. Constraining socio-economic and political conditions and the limited capacity of the coordinating committee of the MWF hindered the development of transformative agency to the extent to which concrete actions were implemented. Findings further revealed that contextualising a Change Laboratory process within the adaptive cycle of a complex social-ecological system, and the particular opportunity context the system presents, could inform the enactment of agency and its potential impact on the transformation of the system. The intervention with the MWF was too short a process to clearly observe the effects of transformative actions on the sustainability of the Makana Local Municipality water system. However, long-chain transformative agency through the development of one-on-one engagements, learning journeys and a reflexive component to the MWF engagements could support transformative pathways to sustainability in the municipality and water management system. The study contributes in-depth insight into the key role of learning as a catalyst in transformative processes. Learning improves the collaborative and adaptive capacity of people, and therefore, water management institutions, to manage explicitly for the complexity inherent in “complex” socialecological systems. It provides empirical evidence as to what enables and constrains “real” participation and learning in grass-roots water governance processes in the context of a shifting national drive towards a more adaptive and developmental Integrated Water Resource Management approach. It further provides methodological contributions to 1) the application of the Change Laboratory method with multi-activity system constellations in developing world contexts and 2) value and limitations of extended and engaged transdisciplinary research. Lastly, it provides practical recommendations to the establishment and sustainable function of both community-based CSOs and multi-stakeholder platforms engaging in water governance processes.
- Full Text:
- Date Issued: 2019
- Authors: Weaver, Matthew James Thanduxolo
- Date: 2019
- Subjects: Government accountability -- South Africa , Civil Society -- South Africa , Political participation -- South Africa , Local government -- South Africa , Water supply -- Management , Water resources development -- South Africa , Water quality management -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/151316 , vital:39051
- Description: The South African state’s ideological commitment to a participatory approach to managing water resources and delivering services in a way that includes all stakeholders warrants critical analysis.Realising this ideological commitment has proved challenging, due largely to the complex historical, political, social, and environmental context of integrated water resource management (IWRM) in South Africa. The overarching aim of this study was to explore and expand the learning of civil societyparticipating in water governance processes at a local government scale. To address this aim a single, in-depth, four-year case study into civil society participation in water governance in the Makana Local Municipality in the Eastern Cape Province of South Africa was conducted between 2014 and 2018. The case study comprised two research phases. Both phases of the research were conducted using an adaptive transdisciplinary and participatory action research approach underpinned by General Complexity Theory. Located at the research-practice interface, the study sought to be transformative and advance both scientific research and societal goals. Qualitative research methods and inductive and deductive modes of inference were used to collect and analyse the data respectively. In the first phase of the study, a Communities of Practice theoretical framing was adopted to investigate the emergence, practice and learning of a civil society organisation (CSO), Water for Dignity (WfD), in response to household water service delivery issues in the municipality. This phase served to build an understanding of factors that enabled and constrained the practice of WfD in addressing local water service issues, and of their role as social learning agents in building water-related knowledge in their community. As participation with the first civil society organisation fragmented, the opportunity arose for local government, the National Department of Water and Sanitation and civil society to co-engage. This opened up the second phase of the research during which the role of a multi-stakeholder platform, the Makana Water Forum (MWF), in enabling democratic water governance was investigated. The MWF was South Africa’s first catchment management forum with an integrated water service and water resource management agenda. In this phase, the study drew on interventionist methodology, Change Laboratory, from Cultural Historical Activity Theory (CHAT) to 1) describe the historical development, composition and shared purpose of the MWF multi-activity system constellation; and to 2) guide participants through seven learning actions (expansive learning cycle) to identify, analyse, model and implement remedial actions to problematic aspects (contradictions) of the MWF practice. Participants of the Change Laboratory workshops built their individual and collective transformative agency (deliberate actions to transform a problematic situation) as they navigated the expansive learning process. The development of this agency was identified through a micro-analysis of agentive talk. The two phases served to advance the exploration of civil society participation from informal participation to address water issues, to formal participation in water governance processes at a local government scale. Findings from the first phase of the research revealed that dedicated and sustained support of partners with distributed expertise and the highly motivated core members of WfD enabled the practice and emergence of the civil society organisation. However, factors such as poor internal leadership, power dynamics between supporting partners, socio-economic constraints and a deeply embedded lack of agency were found to be key constraining factors to WfD’s practice. Findings revealed that learning at WfD team level occurred in four ways, through learning as belonging, learning as doing, learning as experiencing and learning as becoming. The WfD CSO was able to catalyse social learning related to personal water rights; and best practices for improving water quality and water conservation in their wider community of practice. Social learning was fostered mainly through structured citizen engagements offered by WfD. The research provides evidence that civil society organisations can play an important role in bridging water-related knowledge gaps and can foster active citizenship in South African communities. However, despite significant inputs of support and resources through the engaged transdisciplinary research process, the practice and learning outcomes of WfD had a marginal transformative impact on improving the citizen’s every-day water service experiences. Findings from the second phase of the study revealed the MWF to resemble a multi-activity system constellation with a multiple, partially overlapping. interests related to the management of water. The establishment, function and contradictions constraining the function of the MWF were influenced by past cycles of participatory water governance-related activity and practice at national and local scales. Through the Change Laboratory process, 25 contradictions were identified that appeared to constrain the ability of the MWF to enable inclusive and meaningful participatory water governance. Through a process of expansive learning, participants sought to overcome three sets of contradictions grouped as Problem Themes: lack of clear focus of the MWF; representation, representivity and nonattendance; and the MWF relationship with the Makana Local Municipality. Remedial actions modelled and those enacted have improved aspects of the function of the MWF (such as diversified modes of engagement and a more focussed agenda) but have only resulted in incremental shifts towards enabling improved participatory practice, most markedly in building a collaborative relationship and trust between the MWF members, municipal and government officials. The microanalysis of agentive talk revealed seven different expressions of transformative agency. Constraining socio-economic and political conditions and the limited capacity of the coordinating committee of the MWF hindered the development of transformative agency to the extent to which concrete actions were implemented. Findings further revealed that contextualising a Change Laboratory process within the adaptive cycle of a complex social-ecological system, and the particular opportunity context the system presents, could inform the enactment of agency and its potential impact on the transformation of the system. The intervention with the MWF was too short a process to clearly observe the effects of transformative actions on the sustainability of the Makana Local Municipality water system. However, long-chain transformative agency through the development of one-on-one engagements, learning journeys and a reflexive component to the MWF engagements could support transformative pathways to sustainability in the municipality and water management system. The study contributes in-depth insight into the key role of learning as a catalyst in transformative processes. Learning improves the collaborative and adaptive capacity of people, and therefore, water management institutions, to manage explicitly for the complexity inherent in “complex” socialecological systems. It provides empirical evidence as to what enables and constrains “real” participation and learning in grass-roots water governance processes in the context of a shifting national drive towards a more adaptive and developmental Integrated Water Resource Management approach. It further provides methodological contributions to 1) the application of the Change Laboratory method with multi-activity system constellations in developing world contexts and 2) value and limitations of extended and engaged transdisciplinary research. Lastly, it provides practical recommendations to the establishment and sustainable function of both community-based CSOs and multi-stakeholder platforms engaging in water governance processes.
- Full Text:
- Date Issued: 2019
Climatic suitability of Dichrorampha odorata Brown and Zachariades (Lepidoptera: Tortricidae), a shoot-boring moth for the biological control of Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae) in South Africa
- Authors: Nqayi, Slindile Brightness
- Date: 2019
- Subjects: CLIMEX , Chromolaena odorata -- Biological control -- South Africa , Tortricidae -- South Africa , Bioclimatology -- Software
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92208 , vital:30681
- Description: Biological control using natural enemies introduced from the native range is an integral component of the management of Chromolaena odorata, a serious invader in the eastern regions of South Africa. A number of biological control agents for C. odorata have been released in South Africa, and one of them, Dichrorampha odorata, has failed to establish. To understand if D. odorata failed to establish due to climate incompatibility, its thermal physiology was investigated. Thermal tolerance data were used to determine the developmental thresholds and number of generations that D. odorata is capable of going through in South Africa per year. These predictions were generated using CLIMEX temperature data and the degree-day parameters K and t0. Developmental time decreased with increasing temperatures ranging from 20 °C to 30°C, with immature stages not able to complete development at 18°C and 32°C. The developmental threshold, to, was determined as 8.45 °C with 872.4 degree-days required to complete development (K), indicating that D. odorata is capable of producing a maximum number of 6.5 generations per year in South Africa. The CLIMEX data indicated that the east coast regions of South Africa, which are the heaviest invaded areas by C. odorata in South Africa, were climatically most suitable for D. odorata to. D. odorata lower (LLT50) and upper (ULT50) lethal temperatures were -4.5°C and 39.64°C for larvae and 1.83 and 41.02°C for adults, and D. odorata adults were able to maintain locomotory functioning at 4.4 to 43.7°C, respectively. Acclimation at low and high temperatures indicate that when D. odorata was kept at a lower temperature of 20°C for 7 days, it became tolerant to warmer and cooler temperatures (1.95 and 44.41°C) when compared to D. odorata reared at 25°C (3.36 and 43.67°C) and 30°C (5.92 and 42.93°C). Dichrorampha odorata is therefore climatically suitable for release and should establish in South Africa to control C. odorata. The establishment and persistence of D. odorata will not be limited by climatic conditions but rather the distribution of its host weed, C. odorata in South Africa. Also, this study presents a decision-making protocol for the release of D. odorata to allow better performance in the field.
- Full Text:
- Date Issued: 2019
- Authors: Nqayi, Slindile Brightness
- Date: 2019
- Subjects: CLIMEX , Chromolaena odorata -- Biological control -- South Africa , Tortricidae -- South Africa , Bioclimatology -- Software
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92208 , vital:30681
- Description: Biological control using natural enemies introduced from the native range is an integral component of the management of Chromolaena odorata, a serious invader in the eastern regions of South Africa. A number of biological control agents for C. odorata have been released in South Africa, and one of them, Dichrorampha odorata, has failed to establish. To understand if D. odorata failed to establish due to climate incompatibility, its thermal physiology was investigated. Thermal tolerance data were used to determine the developmental thresholds and number of generations that D. odorata is capable of going through in South Africa per year. These predictions were generated using CLIMEX temperature data and the degree-day parameters K and t0. Developmental time decreased with increasing temperatures ranging from 20 °C to 30°C, with immature stages not able to complete development at 18°C and 32°C. The developmental threshold, to, was determined as 8.45 °C with 872.4 degree-days required to complete development (K), indicating that D. odorata is capable of producing a maximum number of 6.5 generations per year in South Africa. The CLIMEX data indicated that the east coast regions of South Africa, which are the heaviest invaded areas by C. odorata in South Africa, were climatically most suitable for D. odorata to. D. odorata lower (LLT50) and upper (ULT50) lethal temperatures were -4.5°C and 39.64°C for larvae and 1.83 and 41.02°C for adults, and D. odorata adults were able to maintain locomotory functioning at 4.4 to 43.7°C, respectively. Acclimation at low and high temperatures indicate that when D. odorata was kept at a lower temperature of 20°C for 7 days, it became tolerant to warmer and cooler temperatures (1.95 and 44.41°C) when compared to D. odorata reared at 25°C (3.36 and 43.67°C) and 30°C (5.92 and 42.93°C). Dichrorampha odorata is therefore climatically suitable for release and should establish in South Africa to control C. odorata. The establishment and persistence of D. odorata will not be limited by climatic conditions but rather the distribution of its host weed, C. odorata in South Africa. Also, this study presents a decision-making protocol for the release of D. odorata to allow better performance in the field.
- Full Text:
- Date Issued: 2019
Clinical psychologists’ perceptions of the phenomenon of schizophrenia in a psychiatric setting in the Eastern Cape, South Africa
- Authors: Hamman, Colette
- Date: 2019
- Subjects: Schizophrenia -- Diagnosis -- South Africa , Schizophrenia -- Treatment -- South Africa , Schizophrenics -- Rehabilitation -- South Africa , Schizophrenics -- South Africa -- Case studies
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/71398 , vital:29845
- Description: Numerous international and South African scholars are critical of the dominant research on the phenomenon of schizophrenia. Rather than refuting dominant biomedical psychiatric conceptualisations of schizophrenia, there is a call for incorporating a focus on the psychology of the person diagnosed with schizophrenia. In South Africa, the integration of the psychosocial components of psychotic experiences into the understanding and treatment of psychosis are still neglected in biomedically-focused psychiatric settings. In relation to this call, the role of clinical psychologists working within these settings seems pertinent. Against this background, this study aimed to explore and describe the perceptions of clinical psychologists, working in a psychiatric setting in South Africa, in relation to the phenomenon of schizophrenia. Informed by a social constructionist theoretical framework, this study utilised a qualitative research design and a semi-structured interview schedule. In-depth, individual interviews were conducted with three clinical psychologists and the transcribed interviews were analysed using thematic analysis. From the data, perceptions were identified as largely polarised in relation to the phenomenon of schizophrenia. These polarised perceptions included: Physical impact of schizophrenia versus social impact of schizophrenia; rehabilitation of schizophrenia versus recovery within schizophrenia; diagnostic frameworks as useful versus diagnostic frameworks as limiting; and institutionally-defined identity versus self-defined identity. In terms of these polarised perceptions, an overarching theme of the medicalisation versus the demedicalisation of schizophrenia was identified. Therefore, the perceptions of clinical psychologists in this study were largely polarised towards either a medicalisation of the phenomenon of schizophrenia or a demedicalisation of it. However, perceptions were also identified that evidenced an integration of the two sides of the polarities, and a holding of tension between seemingly incompatible or incongruent frameworks. The participants perceived psychologists as positioned in the middle ground between the medicalisation and demedicalisation of schizophrenia in a biomedical psychiatric setting. In response to the call for a focus on the psychology of the person diagnosed with schizophrenia, the findings support both the value and the need for an “integration of polarised perceptions”, “holding of the tension”, and “middle ground positioning” of clinicians between medicalised and demedicalised aspects of the phenomenon of schizophrenia.
- Full Text:
- Date Issued: 2019
- Authors: Hamman, Colette
- Date: 2019
- Subjects: Schizophrenia -- Diagnosis -- South Africa , Schizophrenia -- Treatment -- South Africa , Schizophrenics -- Rehabilitation -- South Africa , Schizophrenics -- South Africa -- Case studies
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/71398 , vital:29845
- Description: Numerous international and South African scholars are critical of the dominant research on the phenomenon of schizophrenia. Rather than refuting dominant biomedical psychiatric conceptualisations of schizophrenia, there is a call for incorporating a focus on the psychology of the person diagnosed with schizophrenia. In South Africa, the integration of the psychosocial components of psychotic experiences into the understanding and treatment of psychosis are still neglected in biomedically-focused psychiatric settings. In relation to this call, the role of clinical psychologists working within these settings seems pertinent. Against this background, this study aimed to explore and describe the perceptions of clinical psychologists, working in a psychiatric setting in South Africa, in relation to the phenomenon of schizophrenia. Informed by a social constructionist theoretical framework, this study utilised a qualitative research design and a semi-structured interview schedule. In-depth, individual interviews were conducted with three clinical psychologists and the transcribed interviews were analysed using thematic analysis. From the data, perceptions were identified as largely polarised in relation to the phenomenon of schizophrenia. These polarised perceptions included: Physical impact of schizophrenia versus social impact of schizophrenia; rehabilitation of schizophrenia versus recovery within schizophrenia; diagnostic frameworks as useful versus diagnostic frameworks as limiting; and institutionally-defined identity versus self-defined identity. In terms of these polarised perceptions, an overarching theme of the medicalisation versus the demedicalisation of schizophrenia was identified. Therefore, the perceptions of clinical psychologists in this study were largely polarised towards either a medicalisation of the phenomenon of schizophrenia or a demedicalisation of it. However, perceptions were also identified that evidenced an integration of the two sides of the polarities, and a holding of tension between seemingly incompatible or incongruent frameworks. The participants perceived psychologists as positioned in the middle ground between the medicalisation and demedicalisation of schizophrenia in a biomedical psychiatric setting. In response to the call for a focus on the psychology of the person diagnosed with schizophrenia, the findings support both the value and the need for an “integration of polarised perceptions”, “holding of the tension”, and “middle ground positioning” of clinicians between medicalised and demedicalised aspects of the phenomenon of schizophrenia.
- Full Text:
- Date Issued: 2019
Co (ii) Tetraphenyltetraphenanthroporphyrin@ MWCNTs
- Gu, Tingting, Tao, Jaiyu, Zhu, Weihua, Mack, John, Soy, Rodah C, Nyokong, Tebello, Xu, Haijin, Li, Minzhi, Liang, Xu
- Authors: Gu, Tingting , Tao, Jaiyu , Zhu, Weihua , Mack, John , Soy, Rodah C , Nyokong, Tebello , Xu, Haijin , Li, Minzhi , Liang, Xu
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234580 , vital:50210 , xlink:href="https://doi.org/10.1039/C9NJ01707K"
- Description: Herein, a cobalt(II)tetraphenyltetraphenanthroporphyrin (Co(II)TPTPP) with phenanthrene-fused pyrrole rings was synthesized and characterized. Moreover, a detailed analysis of its optical and redox properties was carried out by comparing the results obtained via optical spectroscopy and electrochemistry with the trends predicted via a series of DFT and TD-DFT calculations. The electrochemistry results demonstrated that the π-expanded Co(II)TPTPP interacted strongly with multiwall carbon nanotubes (MWCNTs), which were finally immobilized on carbon nanotubes via noncovalent interactions and further deposited on glassy carbon. This strong immobilization via π–π stacking between Co(II)TPTPP and MWCNTs leads to significantly stable electrochemically catalyzed hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), which provides a new insight into the understanding electron transfer channels.
- Full Text:
- Date Issued: 2019
- Authors: Gu, Tingting , Tao, Jaiyu , Zhu, Weihua , Mack, John , Soy, Rodah C , Nyokong, Tebello , Xu, Haijin , Li, Minzhi , Liang, Xu
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234580 , vital:50210 , xlink:href="https://doi.org/10.1039/C9NJ01707K"
- Description: Herein, a cobalt(II)tetraphenyltetraphenanthroporphyrin (Co(II)TPTPP) with phenanthrene-fused pyrrole rings was synthesized and characterized. Moreover, a detailed analysis of its optical and redox properties was carried out by comparing the results obtained via optical spectroscopy and electrochemistry with the trends predicted via a series of DFT and TD-DFT calculations. The electrochemistry results demonstrated that the π-expanded Co(II)TPTPP interacted strongly with multiwall carbon nanotubes (MWCNTs), which were finally immobilized on carbon nanotubes via noncovalent interactions and further deposited on glassy carbon. This strong immobilization via π–π stacking between Co(II)TPTPP and MWCNTs leads to significantly stable electrochemically catalyzed hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), which provides a new insight into the understanding electron transfer channels.
- Full Text:
- Date Issued: 2019
Co-encapsulation of rifampicin and isoniazid in crude soybean lecithin liposomes
- Nkanga, Christian I, Noundou, Xavier S, Walker, Roderick B, Krause, Rui W M
- Authors: Nkanga, Christian I , Noundou, Xavier S , Walker, Roderick B , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183536 , vital:44005 , xlink:href="https://doi.org/10.17159/0379-4350/2019/v72a11"
- Description: Despite the well-known anti-mycobacterial actions of isoniazid (INH) and rifampicin (RIF), the clinical success of tuberculosis (TB) therapy requires prolonged administration of multiple drugs in high doses, which often result in frequent adverse effects and low patient adherence. Although liposomes are promising candidates for controlled delivery of anti-TB drug, the high cost of synthetic and highly purified natural lipids currently used in liposomal technology might preclude the universal application of therapeutic liposomes. This work aimed at evaluating the potential of a cost-effective lipid material, crude soybean lecithin (CL), to co-encapsulate RIF and INH for liposomal dual delivery. RIF was encapsulated in CL-liposomes with/without cholesterol using film hydration method, after which INH was incorporated using a freeze–thawing technique. Dynamic light scattering, differential scanning calorimetry, X-ray diffraction and dialysis were used for liposome characterization. Liposomes containing CL alone (CLL) exhibited 90%encapsulation efficiency for RIF and 59%for INH. The mean size and surface charge of CLL were 1114nm and –63mV, respectively. In addition, CLL showed a controlled release profile for the co-encapsulated drugs. CLL would be promising vehicles for macrophage-targeting drug delivery. The present findings demonstrate the feasibility of using CL for preparation of combination products for liposomal delivery.
- Full Text:
- Date Issued: 2019
- Authors: Nkanga, Christian I , Noundou, Xavier S , Walker, Roderick B , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183536 , vital:44005 , xlink:href="https://doi.org/10.17159/0379-4350/2019/v72a11"
- Description: Despite the well-known anti-mycobacterial actions of isoniazid (INH) and rifampicin (RIF), the clinical success of tuberculosis (TB) therapy requires prolonged administration of multiple drugs in high doses, which often result in frequent adverse effects and low patient adherence. Although liposomes are promising candidates for controlled delivery of anti-TB drug, the high cost of synthetic and highly purified natural lipids currently used in liposomal technology might preclude the universal application of therapeutic liposomes. This work aimed at evaluating the potential of a cost-effective lipid material, crude soybean lecithin (CL), to co-encapsulate RIF and INH for liposomal dual delivery. RIF was encapsulated in CL-liposomes with/without cholesterol using film hydration method, after which INH was incorporated using a freeze–thawing technique. Dynamic light scattering, differential scanning calorimetry, X-ray diffraction and dialysis were used for liposome characterization. Liposomes containing CL alone (CLL) exhibited 90%encapsulation efficiency for RIF and 59%for INH. The mean size and surface charge of CLL were 1114nm and –63mV, respectively. In addition, CLL showed a controlled release profile for the co-encapsulated drugs. CLL would be promising vehicles for macrophage-targeting drug delivery. The present findings demonstrate the feasibility of using CL for preparation of combination products for liposomal delivery.
- Full Text:
- Date Issued: 2019
Collaborative health literacy development: a World Health Organization workplace health promotion approach to address tobacco use
- Authors: Duxbury, Theodore Orlando
- Date: 2019
- Subjects: Tobacco use -- Health aspects , Smoking -- Health aspects , Employee health promotion , Employee health promotion -- Computer programs , Rhodes University -- Employees -- Tobacco use
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/104116 , vital:29930
- Description: Background: Non-Communicable Diseases (NCDs) are a major global public health threat and tobacco use in particular is the leading cause of preventable illness and mortality globally. Furthermore, vulnerable and socially disadvantaged people get sicker and die sooner, especially because they are at higher risk of being exposed to harmful products such as tobacco and have limited access to health services. Tobacco use also has a major impact on the workplace, adversely affecting work productivity and increasing absenteeism. Both the living and work environments, therefore, play an important role in contributing towards the NCD epidemic. Demographics, culture, behaviour change reluctance and health literacy are all factors which exacerbate tobacco prevalence in South Africa. Workplace health promotion, however, is not well established in many workplaces. This study aimed to develop, implement and evaluate the effectiveness of a culturallysensitive and contextually-appropriate collaborative workplace health promotion literacy programme on tobacco use, utilizing tailored health information leaflets and the Rhodes University peer educators support staff, guided by the World Health Organization Workplace Health Promotion Framework. Method: The research was conducted using a participatory action research approach, which involved four phases: Firstly, the Exploratory phase assessed tobacco-related health promotion policies and practices at Rhodes University; and established facilitating and constraining factors related to tobacco use. Secondly, the Educational health promotion phase involved designing and testing a health promotion educational intervention to address tobacco use related challenges, which took the form of culturally sensitive and appropriate health information leaflets to be used as an educational intervention Thirdly, in the Implementation phase health promotion training workshops were conducted with volunteering Rhodes University Peer Educators. Finally, an Evaluation phase involved evaluating the tobacco health promotion programme presented to the Rhodes University Peer Educators through a focus group discussion; and evaluating Peer Educator recall on the tobacco related health information discussed during the training workshops through a post-post intervention questionnaire. Eight semi-structured interviews (SSIs) and seven focus group discussions (FGDs) were conducted with support staff, peer educators and key stakeholders to establish the need for a comprehensive workplace health promotion initiative, and to identify the facilitating and constraining factors to conducting such an initiative on tobacco use at the University. Three health information leaflets (HILs) were developed collaboratively with the Peer Educators following a series of scientific, end-user testing approaches. The HILs were tested for readability, comprehension, actionability and suitability. A four-day health promotion training programme was conducted to improve user friendliness, memory retention and recall of the HILs by the peer educators and to improve tobacco related health literacy aspects. The participants’ memory recall was evaluated using a pre- and post-, and post-post-intervention questionnaire to evaluate knowledge transfer. The study participants were also equipped with the completed HILs to distribute to their peers and to use as reference sources of information when needed in future. Results: The peer educators and institutional management supported the need for a tobacco workplace health promotion intervention. The intervention and evaluation phase of this study proved that health information material developed was readable, actionable, suitable, userfriendly, culturally sensitive and contextually appropriate. The workshops resulted in a significant increase in the participants’ tobacco related health knowledge. Through the adoption of a collaborative approach to the research, the participants felt empowered and ready to be agents of change amongst their peers in the workplace. Recommendations: The collective use of external expert reviewers, end-user testing techniques and validated computer programmes are recommended to improve the validity of health promotion research outcomes. A longitudinal study that focus on behaviour change, specifically, with health evaluation and monitoring aspects could be conducted as the next step to this study.
- Full Text:
- Date Issued: 2019
- Authors: Duxbury, Theodore Orlando
- Date: 2019
- Subjects: Tobacco use -- Health aspects , Smoking -- Health aspects , Employee health promotion , Employee health promotion -- Computer programs , Rhodes University -- Employees -- Tobacco use
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/104116 , vital:29930
- Description: Background: Non-Communicable Diseases (NCDs) are a major global public health threat and tobacco use in particular is the leading cause of preventable illness and mortality globally. Furthermore, vulnerable and socially disadvantaged people get sicker and die sooner, especially because they are at higher risk of being exposed to harmful products such as tobacco and have limited access to health services. Tobacco use also has a major impact on the workplace, adversely affecting work productivity and increasing absenteeism. Both the living and work environments, therefore, play an important role in contributing towards the NCD epidemic. Demographics, culture, behaviour change reluctance and health literacy are all factors which exacerbate tobacco prevalence in South Africa. Workplace health promotion, however, is not well established in many workplaces. This study aimed to develop, implement and evaluate the effectiveness of a culturallysensitive and contextually-appropriate collaborative workplace health promotion literacy programme on tobacco use, utilizing tailored health information leaflets and the Rhodes University peer educators support staff, guided by the World Health Organization Workplace Health Promotion Framework. Method: The research was conducted using a participatory action research approach, which involved four phases: Firstly, the Exploratory phase assessed tobacco-related health promotion policies and practices at Rhodes University; and established facilitating and constraining factors related to tobacco use. Secondly, the Educational health promotion phase involved designing and testing a health promotion educational intervention to address tobacco use related challenges, which took the form of culturally sensitive and appropriate health information leaflets to be used as an educational intervention Thirdly, in the Implementation phase health promotion training workshops were conducted with volunteering Rhodes University Peer Educators. Finally, an Evaluation phase involved evaluating the tobacco health promotion programme presented to the Rhodes University Peer Educators through a focus group discussion; and evaluating Peer Educator recall on the tobacco related health information discussed during the training workshops through a post-post intervention questionnaire. Eight semi-structured interviews (SSIs) and seven focus group discussions (FGDs) were conducted with support staff, peer educators and key stakeholders to establish the need for a comprehensive workplace health promotion initiative, and to identify the facilitating and constraining factors to conducting such an initiative on tobacco use at the University. Three health information leaflets (HILs) were developed collaboratively with the Peer Educators following a series of scientific, end-user testing approaches. The HILs were tested for readability, comprehension, actionability and suitability. A four-day health promotion training programme was conducted to improve user friendliness, memory retention and recall of the HILs by the peer educators and to improve tobacco related health literacy aspects. The participants’ memory recall was evaluated using a pre- and post-, and post-post-intervention questionnaire to evaluate knowledge transfer. The study participants were also equipped with the completed HILs to distribute to their peers and to use as reference sources of information when needed in future. Results: The peer educators and institutional management supported the need for a tobacco workplace health promotion intervention. The intervention and evaluation phase of this study proved that health information material developed was readable, actionable, suitable, userfriendly, culturally sensitive and contextually appropriate. The workshops resulted in a significant increase in the participants’ tobacco related health knowledge. Through the adoption of a collaborative approach to the research, the participants felt empowered and ready to be agents of change amongst their peers in the workplace. Recommendations: The collective use of external expert reviewers, end-user testing techniques and validated computer programmes are recommended to improve the validity of health promotion research outcomes. A longitudinal study that focus on behaviour change, specifically, with health evaluation and monitoring aspects could be conducted as the next step to this study.
- Full Text:
- Date Issued: 2019
Collaborative stewardship in multifunctional landscapes: toward relational, pluralistic approaches
- Cockburn, Jessica J, Cundell, Georgina, Shackleton, Shenoa, Rouget, Mathieu, Zwinkels, Marijn, Cornelius, Susanna A, Metcalf, Liz, van den Broek, D
- Authors: Cockburn, Jessica J , Cundell, Georgina , Shackleton, Shenoa , Rouget, Mathieu , Zwinkels, Marijn , Cornelius, Susanna A , Metcalf, Liz , van den Broek, D
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/390297 , vital:68535 , xlink:href="https://doi.org/10.5751/ES-11085-240432"
- Description: Landscape stewardship offers a means to put social-ecological approaches to stewardship into practice. The growing interest in landscape stewardship has led to a focus on multistakeholder collaboration. Although there is a significant body of literature on collaborative management and governance of natural resources, the particular challenges posed by multifunctional landscapes, in which there are often contested interests, require closer attention. We present a case study from South Africa to investigate how collaborative stewardship can be fostered in contested multifunctional landscapes. We conducted this research through an engaged transdisciplinary research partnership in which we integrated social-ecological practitioner and academic knowledge to gain an in-depth understanding of the challenges of fostering collaboration. We identified five overarching factors that influence collaboration: contextual, institutional, social-relational, individual, and political-historical. Collaborative stewardship approaches focused on the development of formal governance institutions appear to be most successful if enabling individual and social-relational conditions are in place. Our case study, characterized by high social diversity, inequity, and contestation, suggests that consensus-driven approaches to collaboration are unlikely to result in equitable and sustainable landscape stewardship in such contexts. We therefore suggest an approach that focuses on enhancing individual and social-relational enablers. Moreover, we propose a bottom-up patchwork approach to collaborative stewardship premised on the notion of pluralism. This would focus on building new interpersonal relationships and collaborative capacity through small collective actions. Taking a relational, pluralistic approach to fostering collaborative stewardship is particularly important in contested, socially heterogeneous landscapes. Drawing on our study and the literature, we propose guiding principles for implementing relational, pluralistic approaches to collaborative stewardship and suggest future research directions for supporting such approaches.
- Full Text:
- Date Issued: 2019
- Authors: Cockburn, Jessica J , Cundell, Georgina , Shackleton, Shenoa , Rouget, Mathieu , Zwinkels, Marijn , Cornelius, Susanna A , Metcalf, Liz , van den Broek, D
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/390297 , vital:68535 , xlink:href="https://doi.org/10.5751/ES-11085-240432"
- Description: Landscape stewardship offers a means to put social-ecological approaches to stewardship into practice. The growing interest in landscape stewardship has led to a focus on multistakeholder collaboration. Although there is a significant body of literature on collaborative management and governance of natural resources, the particular challenges posed by multifunctional landscapes, in which there are often contested interests, require closer attention. We present a case study from South Africa to investigate how collaborative stewardship can be fostered in contested multifunctional landscapes. We conducted this research through an engaged transdisciplinary research partnership in which we integrated social-ecological practitioner and academic knowledge to gain an in-depth understanding of the challenges of fostering collaboration. We identified five overarching factors that influence collaboration: contextual, institutional, social-relational, individual, and political-historical. Collaborative stewardship approaches focused on the development of formal governance institutions appear to be most successful if enabling individual and social-relational conditions are in place. Our case study, characterized by high social diversity, inequity, and contestation, suggests that consensus-driven approaches to collaboration are unlikely to result in equitable and sustainable landscape stewardship in such contexts. We therefore suggest an approach that focuses on enhancing individual and social-relational enablers. Moreover, we propose a bottom-up patchwork approach to collaborative stewardship premised on the notion of pluralism. This would focus on building new interpersonal relationships and collaborative capacity through small collective actions. Taking a relational, pluralistic approach to fostering collaborative stewardship is particularly important in contested, socially heterogeneous landscapes. Drawing on our study and the literature, we propose guiding principles for implementing relational, pluralistic approaches to collaborative stewardship and suggest future research directions for supporting such approaches.
- Full Text:
- Date Issued: 2019
Colloquial terms used in young adults’ talk about sexual practices, sexual subjectivities and sexual desires’
- Authors: Robertson, Cassandra Ann
- Date: 2019
- Subjects: Youth -- Sexual behavior , Sex in popular culture , Communication and sex , Language and sex
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/96551 , vital:31293
- Description: Much of the growth in sexualities‘ research has taken the form of large scale surveys, but there is also increased interest in qualitative approaches that provide useful insights into the experiential and subjective aspects of sexuality, and illuminate the social and cultural contexts shaping these experiences. The reason for this research is to provide a richer understanding of the language that young people employ when speaking about sexuality. This study examines young adults‘ talk about sexualities with a special focus on the way in which colloquial terms are deployed in this talk and through the presence of gendered and/or heteronormative assumptions. Data consisted of posts off a student-led social media site and the study design employed was a validity check group interview. The social media site allowed its followers to post anonymously about a range of sexualities related issues. Data were analysed thematically, using a deductive, critical, and post-structuralist approach with key insights drawn on from Michael Foucault, Adrienne Rich, Gayle Rubin, Judith Butler and Rosalind Gill. Three overarching themes emerged: young adults spoke to sexual practices, sexual subjectivities and sexual desires. A major focus of this talk is casual sex. This talk showed that there are attempts to undermine gendered and heteronormative power relations, for example, non-normative sexual experiences were not seen as deviant, although those who were engaging in monogamy and casual sex were constructed as deviant sexual subjects. Yet underpinning of these power relations still took place, for example, in the female missing discourse of desire, the internalisation of male sexual desires over female sexual desires and the sexual double standard. There was a clear divide between the sexual practices and sexual subjectivities that were considered to be good and bad. This research therefore has the potential to benefit sexuality interventions by bringing into sharp focus the actual experiences of young adults.
- Full Text:
- Date Issued: 2019
- Authors: Robertson, Cassandra Ann
- Date: 2019
- Subjects: Youth -- Sexual behavior , Sex in popular culture , Communication and sex , Language and sex
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/96551 , vital:31293
- Description: Much of the growth in sexualities‘ research has taken the form of large scale surveys, but there is also increased interest in qualitative approaches that provide useful insights into the experiential and subjective aspects of sexuality, and illuminate the social and cultural contexts shaping these experiences. The reason for this research is to provide a richer understanding of the language that young people employ when speaking about sexuality. This study examines young adults‘ talk about sexualities with a special focus on the way in which colloquial terms are deployed in this talk and through the presence of gendered and/or heteronormative assumptions. Data consisted of posts off a student-led social media site and the study design employed was a validity check group interview. The social media site allowed its followers to post anonymously about a range of sexualities related issues. Data were analysed thematically, using a deductive, critical, and post-structuralist approach with key insights drawn on from Michael Foucault, Adrienne Rich, Gayle Rubin, Judith Butler and Rosalind Gill. Three overarching themes emerged: young adults spoke to sexual practices, sexual subjectivities and sexual desires. A major focus of this talk is casual sex. This talk showed that there are attempts to undermine gendered and heteronormative power relations, for example, non-normative sexual experiences were not seen as deviant, although those who were engaging in monogamy and casual sex were constructed as deviant sexual subjects. Yet underpinning of these power relations still took place, for example, in the female missing discourse of desire, the internalisation of male sexual desires over female sexual desires and the sexual double standard. There was a clear divide between the sexual practices and sexual subjectivities that were considered to be good and bad. This research therefore has the potential to benefit sexuality interventions by bringing into sharp focus the actual experiences of young adults.
- Full Text:
- Date Issued: 2019