Characteristics of the thermoluminescence of Sm3+-doped P2O5-K2O-MgO-Al2O3-ZnF2 glass
- Thomas, Sunil, Chithambo, Makaiko L
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/109979 , vital:33211 , https://doi.org/10.1016/j.radmeas.2018.06.005
- Description: We report the thermoluminescence of Sm3+-doped P2O5-K2O-MgO-Al2O3-ZnF2 glass. A glow-curve measured at 1 °C/s after beta irradiation to 10 Gy shows two peaks; a broad high intensity one at 214.0 ± 0.4 °C and a weaker intensity peak at 75.2 ± 0.8 °C. The dependence of peak position on partial heating as well as on irradiation suggest that the main peak at 214 °C is a combination of several overlapping peaks. The activation energy of the different components of the main peak, calculated using the initial-rise method, differ showing that the components are distinct. The reproducibility, fading and dose response were examined by considering the dominant component of the main peak. The intensity of the peak changes with heating rate in a manner consistent with thermal quenching.
- Full Text: false
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/109979 , vital:33211 , https://doi.org/10.1016/j.radmeas.2018.06.005
- Description: We report the thermoluminescence of Sm3+-doped P2O5-K2O-MgO-Al2O3-ZnF2 glass. A glow-curve measured at 1 °C/s after beta irradiation to 10 Gy shows two peaks; a broad high intensity one at 214.0 ± 0.4 °C and a weaker intensity peak at 75.2 ± 0.8 °C. The dependence of peak position on partial heating as well as on irradiation suggest that the main peak at 214 °C is a combination of several overlapping peaks. The activation energy of the different components of the main peak, calculated using the initial-rise method, differ showing that the components are distinct. The reproducibility, fading and dose response were examined by considering the dominant component of the main peak. The intensity of the peak changes with heating rate in a manner consistent with thermal quenching.
- Full Text: false
Characterization and computational studies of a co-crystal of 2-aminobenzimidazole and 2-[(benzoylcarbamothioyl) amino] propanoic acid
- Odame, Felix, Hosten, Eric C, Betz, Richard, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447030 , vital:74578 , xlink:href="https://doi.org/10.1134/S0022476618050268"
- Description: A novel co-crystal of 2-aminobenzimidazole and 2-[(benzoylcarbamothioyl)amino] propanoic acid is synthesized and characterized by spectroscopy, elemental analysis, GC-MS, and single crystal XRD. A computation of the structures involved in the formation of the co-crystal are carried out and their contribution to reactivity is explained.
- Full Text:
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447030 , vital:74578 , xlink:href="https://doi.org/10.1134/S0022476618050268"
- Description: A novel co-crystal of 2-aminobenzimidazole and 2-[(benzoylcarbamothioyl)amino] propanoic acid is synthesized and characterized by spectroscopy, elemental analysis, GC-MS, and single crystal XRD. A computation of the structures involved in the formation of the co-crystal are carried out and their contribution to reactivity is explained.
- Full Text:
Characterizing early drug resistance-related events using geometric ensembles from HIV protease dynamics:
- Sheik Amamuddy, Olivier, Bishop, Nigel T, Tastan Bishop, Özlem
- Authors: Sheik Amamuddy, Olivier , Bishop, Nigel T , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148126 , vital:38712 , DOI: 10.1038/s41598-018-36041-8
- Description: The use of antiretrovirals (ARVs) has drastically improved the life quality and expectancy of HIV patients since their introduction in health care. Several millions are still afflicted worldwide by HIV and ARV resistance is a constant concern for both healthcare practitioners and patients, as while treatment options are finite, the virus constantly adapts via complex mutation patterns to select for resistant strains under the pressure of drug treatment. The HIV protease is a crucial enzyme for viral maturation and has been a game changing drug target since the first application. Due to similarities in protease inhibitor designs, drug cross-resistance is not uncommon across ARVs of the same class.
- Full Text:
- Authors: Sheik Amamuddy, Olivier , Bishop, Nigel T , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148126 , vital:38712 , DOI: 10.1038/s41598-018-36041-8
- Description: The use of antiretrovirals (ARVs) has drastically improved the life quality and expectancy of HIV patients since their introduction in health care. Several millions are still afflicted worldwide by HIV and ARV resistance is a constant concern for both healthcare practitioners and patients, as while treatment options are finite, the virus constantly adapts via complex mutation patterns to select for resistant strains under the pressure of drug treatment. The HIV protease is a crucial enzyme for viral maturation and has been a game changing drug target since the first application. Due to similarities in protease inhibitor designs, drug cross-resistance is not uncommon across ARVs of the same class.
- Full Text:
Chasing shadow and make believe
- Authors: Mofokeng, Reikanne
- Date: 2018
- Subjects: Creative writing (Higher education) -- South Africa , South African fiction (English) -- 21st century , Science fiction, South African (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63626 , vital:28449
- Description: My thesis is a science fiction novella. It follows the story of an adolescent boy, Shadow, and a little girl, Makebelieve, in an ahistorical future. The world that they traverse is earth, after being nursed back to health, by technologically advanced Southern African societies. A series of inexplicable astronomical events leads to their being hunted down. Through the travels of Shadow and Makebelieve I show how the world and the societies around them operate. I am inspired by Samuel R Delaney’s Aye, Gomorrah and Derrick Bell’s The Space Traders, because of their prowess in world building and exploration of complex and innovative ideas.
- Full Text:
- Authors: Mofokeng, Reikanne
- Date: 2018
- Subjects: Creative writing (Higher education) -- South Africa , South African fiction (English) -- 21st century , Science fiction, South African (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63626 , vital:28449
- Description: My thesis is a science fiction novella. It follows the story of an adolescent boy, Shadow, and a little girl, Makebelieve, in an ahistorical future. The world that they traverse is earth, after being nursed back to health, by technologically advanced Southern African societies. A series of inexplicable astronomical events leads to their being hunted down. Through the travels of Shadow and Makebelieve I show how the world and the societies around them operate. I am inspired by Samuel R Delaney’s Aye, Gomorrah and Derrick Bell’s The Space Traders, because of their prowess in world building and exploration of complex and innovative ideas.
- Full Text:
Chemical weathering on selected nunataks in western Dronning Maud Land, Antarctica
- Authors: Knox, Jenna Tracy
- Date: 2018
- Subjects: Glacial climates -- Antarctica -- Queen Maud Land , Glaciology -- Antarctica -- Queen Maud Land , Chemical weathering -- Antarctica -- Queen Maud Land , Atmospheric carbon dioxide -- Environmental aspects , Climatic changes -- Antarctica -- Queen Maud Land , Nunataks -- Antarctica -- Queen Maud Land
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61658 , vital:28046
- Description: High latitude areas are sensitive to the impacts of climate change, and it is expected that the impact of greenhouse warming will be much higher in the polar regions than in any other climatic zones, with the most highly affected area being that of the Antarctic rim (Barsch, 1993). Weathering and pedogenic processes respond to variations in climate, with models predicting that chemical weathering may increase synchronously with global carbon dioxide levels increase, due to dissolution rates and the erosional impact of hydrological cycles in warming climates (Anderson & Anderson, 2010). As liquid water becomes more available in Antarctica the potential for chemical weathering, due to a less moisture-limited environment and increased temperatures, increases (Convey et al., 2009). Weathering processes are important for soil formation and the production of fine-grained material, with chemical weathering being an active constituent of this. Increased rates of soil formation are likely to occur, with global climate changes resulting in greater chemical weathering occurring in Antarctica. Opportunistic sampling was conducted during the Austral summer of 2016/2017, whereby rock, snow and meltwater samples were taken at various sites within the western portion of Dronning Maud Land of Antarctica. Rock samples were placed in resin, and cut with a diamond saw to create thin sections. Optical microscopy and scanning transmission electron microscopy (STEM) were used to analyse mineral weight percentage with depth. Twelve soil samples were dried and weighed, sieved and statistically represented according to particle size. Inductively coupled plasma mass spectrometry (ICP-MS) determined the geochemical analysis for 10 water and snow samples. Rock hardness was inferred through the use of an Equotip, with rebound values recorded for multiple rock faces and samples. Thermal regimes of rock temperature was further recorded using a FLIR infrared camera, and documented for each rock face over a 24 hour period at 2 hourly intervals. The products of increased chemical weathering were evident from particle size analysis; samples were very poorly sorted in nature, and undergo in situ weathering, whereby products were not removed by erosional processes. Weathering rinds were found to be siliceous and ferric, depending on parent lithology. Ferric ratios increased in wt.% from the substrate rock to the external surface, creating the red, iron rich crusts noted on the hand specimens. The observable chemical weathering was found adjacent to intrusions through Precambrian dolerites. Geochemical analysis revealed thin, carbonaceous features, with impurity-rich layers, characteristic of speleothem formation. Carbonaceous layers did not follow underlying substrate features, rather deposited at the external surface, upon which, further precipitation growth could occur, creating karst features. Extensive gypsum coatings (>2mm) under BSE imagery were identified, with the abundance of gypsum salts (below surface level) and rock coatings indicating active sulphuric acid weathering, in western Dronning Maud Land, Antarctica. Were mechanical processes faster than chemical, weathering rinds and solution features on silicate rocks would be uncommon in the Antarctic, periglacial landscape. However, this is not the case as the existence of these landforms implies that chemical weathering may occur faster than mechanical weathering processes (Pope et al., 1995). In a changing world, one needs to monitor these processes at a micro-scale in order to fully understand how periglacial environments react to global climatic changes, and the subsequent impacts on these sensitive environments.
- Full Text:
- Authors: Knox, Jenna Tracy
- Date: 2018
- Subjects: Glacial climates -- Antarctica -- Queen Maud Land , Glaciology -- Antarctica -- Queen Maud Land , Chemical weathering -- Antarctica -- Queen Maud Land , Atmospheric carbon dioxide -- Environmental aspects , Climatic changes -- Antarctica -- Queen Maud Land , Nunataks -- Antarctica -- Queen Maud Land
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61658 , vital:28046
- Description: High latitude areas are sensitive to the impacts of climate change, and it is expected that the impact of greenhouse warming will be much higher in the polar regions than in any other climatic zones, with the most highly affected area being that of the Antarctic rim (Barsch, 1993). Weathering and pedogenic processes respond to variations in climate, with models predicting that chemical weathering may increase synchronously with global carbon dioxide levels increase, due to dissolution rates and the erosional impact of hydrological cycles in warming climates (Anderson & Anderson, 2010). As liquid water becomes more available in Antarctica the potential for chemical weathering, due to a less moisture-limited environment and increased temperatures, increases (Convey et al., 2009). Weathering processes are important for soil formation and the production of fine-grained material, with chemical weathering being an active constituent of this. Increased rates of soil formation are likely to occur, with global climate changes resulting in greater chemical weathering occurring in Antarctica. Opportunistic sampling was conducted during the Austral summer of 2016/2017, whereby rock, snow and meltwater samples were taken at various sites within the western portion of Dronning Maud Land of Antarctica. Rock samples were placed in resin, and cut with a diamond saw to create thin sections. Optical microscopy and scanning transmission electron microscopy (STEM) were used to analyse mineral weight percentage with depth. Twelve soil samples were dried and weighed, sieved and statistically represented according to particle size. Inductively coupled plasma mass spectrometry (ICP-MS) determined the geochemical analysis for 10 water and snow samples. Rock hardness was inferred through the use of an Equotip, with rebound values recorded for multiple rock faces and samples. Thermal regimes of rock temperature was further recorded using a FLIR infrared camera, and documented for each rock face over a 24 hour period at 2 hourly intervals. The products of increased chemical weathering were evident from particle size analysis; samples were very poorly sorted in nature, and undergo in situ weathering, whereby products were not removed by erosional processes. Weathering rinds were found to be siliceous and ferric, depending on parent lithology. Ferric ratios increased in wt.% from the substrate rock to the external surface, creating the red, iron rich crusts noted on the hand specimens. The observable chemical weathering was found adjacent to intrusions through Precambrian dolerites. Geochemical analysis revealed thin, carbonaceous features, with impurity-rich layers, characteristic of speleothem formation. Carbonaceous layers did not follow underlying substrate features, rather deposited at the external surface, upon which, further precipitation growth could occur, creating karst features. Extensive gypsum coatings (>2mm) under BSE imagery were identified, with the abundance of gypsum salts (below surface level) and rock coatings indicating active sulphuric acid weathering, in western Dronning Maud Land, Antarctica. Were mechanical processes faster than chemical, weathering rinds and solution features on silicate rocks would be uncommon in the Antarctic, periglacial landscape. However, this is not the case as the existence of these landforms implies that chemical weathering may occur faster than mechanical weathering processes (Pope et al., 1995). In a changing world, one needs to monitor these processes at a micro-scale in order to fully understand how periglacial environments react to global climatic changes, and the subsequent impacts on these sensitive environments.
- Full Text:
Chipangano: vigilantism and community responses in Mbare District, Zimbabwe, c.2000-2013
- Authors: Munyarari, Tinashe
- Date: 2018
- Subjects: Vigilantism Zimbabwe Mbare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe History 1980- , Vigilantism Zimbabwe Mbare Public opinion , Collective memory Zimbabwe Mbare
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62126 , vital:28130
- Description: This study examines an aspect of Zimbabwe’s political history, namely the emergence and operations of Chipangano vigilante group in Mbare (2000-2013) and how the community responded to the scourges of this vigilante group. This study shows that Chipangano, which means a pact, was formed with the intention to extend ZANU-PF patronage system, canvassing support and regain control of Mbare district from the MDC. The group consolidated itself as a shadow militia group for ZANU-PF that intimidated the opposition parties and coerced the general populace to attend ZANU-PF functions. It also shows that the vigilante group seized Harare City Council’s duties, such as collecting gate-takings from local and long distance public transport at Mbare Bus Terminal; controlling allocations of market stalls and collecting rents from market stalls, for personal benefits. The group also politicised the access to local state property. Chipangano’s collusion with ZANU-PF and state structures licensed it to engage in criminal activities with impunity, thus this thesis seeks to understand the relationship between the vigilantes, ZANU-PF and state structures. The activities of Chipangano such as abduction, intimidation, beatings, killings and displacement of people resulted in social trauma. This thesis will also explore how this phase of violence is remembered today by the research informants. , Thesis (MA) -- Faculty of Humanities, History, 2018
- Full Text:
- Authors: Munyarari, Tinashe
- Date: 2018
- Subjects: Vigilantism Zimbabwe Mbare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe History 1980- , Vigilantism Zimbabwe Mbare Public opinion , Collective memory Zimbabwe Mbare
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62126 , vital:28130
- Description: This study examines an aspect of Zimbabwe’s political history, namely the emergence and operations of Chipangano vigilante group in Mbare (2000-2013) and how the community responded to the scourges of this vigilante group. This study shows that Chipangano, which means a pact, was formed with the intention to extend ZANU-PF patronage system, canvassing support and regain control of Mbare district from the MDC. The group consolidated itself as a shadow militia group for ZANU-PF that intimidated the opposition parties and coerced the general populace to attend ZANU-PF functions. It also shows that the vigilante group seized Harare City Council’s duties, such as collecting gate-takings from local and long distance public transport at Mbare Bus Terminal; controlling allocations of market stalls and collecting rents from market stalls, for personal benefits. The group also politicised the access to local state property. Chipangano’s collusion with ZANU-PF and state structures licensed it to engage in criminal activities with impunity, thus this thesis seeks to understand the relationship between the vigilantes, ZANU-PF and state structures. The activities of Chipangano such as abduction, intimidation, beatings, killings and displacement of people resulted in social trauma. This thesis will also explore how this phase of violence is remembered today by the research informants. , Thesis (MA) -- Faculty of Humanities, History, 2018
- Full Text:
Citizen science, treatment and microbial compliance monitoring in rainwater harvesting in Namibia
- Angala, Hallo Angaleni Nameya
- Authors: Angala, Hallo Angaleni Nameya
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62082 , vital:28105
- Description: Expected release date-April 2020
- Full Text:
- Authors: Angala, Hallo Angaleni Nameya
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62082 , vital:28105
- Description: Expected release date-April 2020
- Full Text:
Click chemistry electrode modification using 4-ethynylbenzyl substituted cobalt phthalocyanine for applications in electrocatalysis
- Mpeta, Lekhetho S, Fomo, Gertrude, Nyokong, Tebello
- Authors: Mpeta, Lekhetho S , Fomo, Gertrude , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187626 , vital:44681 , xlink:href="• https://doi.org/10.1080/00958972.2018.1466118"
- Description: In this work, we report on the synthesis and applications of a new cobalt tetrakis 4-((4-ethynylbenzyl) oxy) phthalocyanine (3) for the detection of hydrazine. The glassy carbon electrode (GCE) was first grafted through diazotization, providing the GCE surface layer with azide groups. Thereafter, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper(I) catalyst was used to “click” complex 3 to the grafted surface of GCE. The new platform was then characterized using cyclic voltammetry (CV), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). This work shows that 3 is an effective sensor with sensitivity of 91.5 μA mM−1 and limit of detection of 3.28 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Authors: Mpeta, Lekhetho S , Fomo, Gertrude , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187626 , vital:44681 , xlink:href="• https://doi.org/10.1080/00958972.2018.1466118"
- Description: In this work, we report on the synthesis and applications of a new cobalt tetrakis 4-((4-ethynylbenzyl) oxy) phthalocyanine (3) for the detection of hydrazine. The glassy carbon electrode (GCE) was first grafted through diazotization, providing the GCE surface layer with azide groups. Thereafter, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper(I) catalyst was used to “click” complex 3 to the grafted surface of GCE. The new platform was then characterized using cyclic voltammetry (CV), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). This work shows that 3 is an effective sensor with sensitivity of 91.5 μA mM−1 and limit of detection of 3.28 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
Code-switching as a pedagogical strategy in classroom settings: the case of township schools in a South African Metropolitan Municipality
- Authors: Marawu, Sithembele
- Date: 2018
- Subjects: Code switching (Linguistics) , Multilingual education -- South Africa , Education, Bilingual -- South Africa , Language and languages -- Study and teaching -- Bilingual method , English language -- Social aspects -- South Africa , Language and education -- South Africa , Language and education -- Social aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62406 , vital:28173
- Description: The purpose of this study was to explore the use of code-switching as a pedagogical strategy in bi/multilingual classroom settings. It was prompted by the widespread use of codeswitching (CS) in classrooms, particularly in South African rural and township schools. This study highlighted that learners from disadvantaged backgrounds struggle to learn through the medium of English but aspire to acquire it because of its association with socio-economic advancement. However, poor proficiency in English excludes them from being part of the country's economy. Research studies show that there is a shift from the old orthodoxy which perceived CS as undesirable in classrooms to a new orthodoxy that acknowledges its academic contribution in classrooms. Although more research on classroom CS has been done, this study identified the need for development of new strategies on how to use CS effectively in classrooms as a linguistic and pedagogical resource. In line with critical classroom ethnography, qualitative interpretation of data was used to understand the teachers' discourse behaviour. Additionally, non-probability sampling - specifically purposive sampling - was used to collect data. These methods and approaches assisted in the analysis of the discourse of the three teachers who served as units of analysis in this study. These teachers relied on CS to impart the content of their subjects to the learners. It transpired from data analysis that teachers use CS in classrooms to achieve various functions like social and pedagogical functions. Another finding is that the switches teachers make do not affect the syntactic structure of the matrix language. Moreover, CS enhances understanding of the subject matter. This study concludes by stating that as learners are emergent bilinguals, additive bilingualism would be more ideal in the South African situation than subtractive bilingualism which parents and learners seem to prefer. Lastly, there is a need to harness CS as a communicative and pedagogical resource in classrooms.
- Full Text:
- Authors: Marawu, Sithembele
- Date: 2018
- Subjects: Code switching (Linguistics) , Multilingual education -- South Africa , Education, Bilingual -- South Africa , Language and languages -- Study and teaching -- Bilingual method , English language -- Social aspects -- South Africa , Language and education -- South Africa , Language and education -- Social aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62406 , vital:28173
- Description: The purpose of this study was to explore the use of code-switching as a pedagogical strategy in bi/multilingual classroom settings. It was prompted by the widespread use of codeswitching (CS) in classrooms, particularly in South African rural and township schools. This study highlighted that learners from disadvantaged backgrounds struggle to learn through the medium of English but aspire to acquire it because of its association with socio-economic advancement. However, poor proficiency in English excludes them from being part of the country's economy. Research studies show that there is a shift from the old orthodoxy which perceived CS as undesirable in classrooms to a new orthodoxy that acknowledges its academic contribution in classrooms. Although more research on classroom CS has been done, this study identified the need for development of new strategies on how to use CS effectively in classrooms as a linguistic and pedagogical resource. In line with critical classroom ethnography, qualitative interpretation of data was used to understand the teachers' discourse behaviour. Additionally, non-probability sampling - specifically purposive sampling - was used to collect data. These methods and approaches assisted in the analysis of the discourse of the three teachers who served as units of analysis in this study. These teachers relied on CS to impart the content of their subjects to the learners. It transpired from data analysis that teachers use CS in classrooms to achieve various functions like social and pedagogical functions. Another finding is that the switches teachers make do not affect the syntactic structure of the matrix language. Moreover, CS enhances understanding of the subject matter. This study concludes by stating that as learners are emergent bilinguals, additive bilingualism would be more ideal in the South African situation than subtractive bilingualism which parents and learners seem to prefer. Lastly, there is a need to harness CS as a communicative and pedagogical resource in classrooms.
- Full Text:
Combined spectral and stimulated luminescence study of charge trapping and recombination processes in α-Al2O3:C
- Authors: Nyirenda, Angel Newton
- Date: 2018
- Subjects: Luminescence , Thermoluminescence , Luminescence spectroscopy , Carbon-doped aluminium oxide , Radioluminescence , Time-resolved X-ray excited optical luminescence
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62683 , vital:28235
- Description: The main objective of this project was to gain a deeper and better understanding of the luminescence processes in a-Al₂O₃:C, a highly-sensitive dosimetric material, using a combined spectral and stimulated luminescence study. The spectral studies concentrated on the emission spectra obtained using X-ray induced radioluminescence (XERL), thermoluminescence (XETL) and time-resolved X-ray excited optical luminescence (TR-XEOL) techniques. The stimulated luminescence studies were based on thermoluminescence (TL), optically stimulated luminescence (OSL) and phototransferred TL (PTTL) methods that were used in the study of the radiation-induced defects at high beta-doses and the deep traps, that is, traps with thermal depths beyond 500°C. The spectral and stimulated luminescence measurements were carried out using a high sensitivity luminescence spectrometer and a Ris0 TL/OSL Model DA-20 Reader, respectively. The XERL emission spectrum measured at room temperature shows seven gaussian peaks associated with F-centres (420 nm), F+-centres (334 nm), F2+-centres (559 nm), Stoke’s vibronic band of Cr3+ (671 nm), Cr3+ R-line emission (694 nm), anti-Stokes vibronic band of Cr3+ (710 nm) and an unidentified emission band (260-300 nm) which we associate with hole recombinations at a luminescence centre. The 694-nm R-line emission from Cr3+ impurity ions is most likely due to recombination of holes at Cr2+ during stimulated luminescence and as a result of an intracentre excitation of Cr3+ in photoluminescence (PL) due to photon absorption. The Cr3+ emission decreases in intensity, whereas the intensity of F-centre emission band is almost constant with repeated XERL measurements. Depending on the amount of X-ray irradiation dose, both holes and/or electrons may take place in the emission processes of peaks I (30-80°C), II (90-250°C) and III (250-320°C) during a TL readout, albeit, electron recombination is dominant regardless of dose. At higher doses, the XETL emission spectra indicate that the dominant band associated with TL peak III (250-320°C) in the material, shifts from F-centre to Cr3+. Using the deep-traps OSL, it has been confirmed that the main TL trap is also the main OSL trap whereas the TL traps lying in the temperature range of 400-550°C constitute the secondary OSL traps. There is evidence of strong retrapping at the main trap during optical stimulation of charges from the secondary OSL traps and the deep traps and that the retrapping occurs via the delocalized bands. At high-irradiation beta-doses, aggregate defect centres which significantly alter the TL and OSL properties, are induced in the material. The induced aggregate centres get completely obliterated by heating a sample to 700°C. The radiation-induced defects cause the main TL peak to shift towards higher temperatures, increase its FWHM, reduce its maximum intensity and cause an underestimation of both the activation energy and order of kinetics of the peak. On the other hand, the OSL response of the material is enhanced following a high-irradiation dose. During sample storage in the dark at ambient temperature, charges do migrate from the deep traps (donors) to the main and intermediate traps (acceptors) and that the major donor traps during this charge transfer phenomenon lie between 500-600°C.
- Full Text:
- Authors: Nyirenda, Angel Newton
- Date: 2018
- Subjects: Luminescence , Thermoluminescence , Luminescence spectroscopy , Carbon-doped aluminium oxide , Radioluminescence , Time-resolved X-ray excited optical luminescence
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62683 , vital:28235
- Description: The main objective of this project was to gain a deeper and better understanding of the luminescence processes in a-Al₂O₃:C, a highly-sensitive dosimetric material, using a combined spectral and stimulated luminescence study. The spectral studies concentrated on the emission spectra obtained using X-ray induced radioluminescence (XERL), thermoluminescence (XETL) and time-resolved X-ray excited optical luminescence (TR-XEOL) techniques. The stimulated luminescence studies were based on thermoluminescence (TL), optically stimulated luminescence (OSL) and phototransferred TL (PTTL) methods that were used in the study of the radiation-induced defects at high beta-doses and the deep traps, that is, traps with thermal depths beyond 500°C. The spectral and stimulated luminescence measurements were carried out using a high sensitivity luminescence spectrometer and a Ris0 TL/OSL Model DA-20 Reader, respectively. The XERL emission spectrum measured at room temperature shows seven gaussian peaks associated with F-centres (420 nm), F+-centres (334 nm), F2+-centres (559 nm), Stoke’s vibronic band of Cr3+ (671 nm), Cr3+ R-line emission (694 nm), anti-Stokes vibronic band of Cr3+ (710 nm) and an unidentified emission band (260-300 nm) which we associate with hole recombinations at a luminescence centre. The 694-nm R-line emission from Cr3+ impurity ions is most likely due to recombination of holes at Cr2+ during stimulated luminescence and as a result of an intracentre excitation of Cr3+ in photoluminescence (PL) due to photon absorption. The Cr3+ emission decreases in intensity, whereas the intensity of F-centre emission band is almost constant with repeated XERL measurements. Depending on the amount of X-ray irradiation dose, both holes and/or electrons may take place in the emission processes of peaks I (30-80°C), II (90-250°C) and III (250-320°C) during a TL readout, albeit, electron recombination is dominant regardless of dose. At higher doses, the XETL emission spectra indicate that the dominant band associated with TL peak III (250-320°C) in the material, shifts from F-centre to Cr3+. Using the deep-traps OSL, it has been confirmed that the main TL trap is also the main OSL trap whereas the TL traps lying in the temperature range of 400-550°C constitute the secondary OSL traps. There is evidence of strong retrapping at the main trap during optical stimulation of charges from the secondary OSL traps and the deep traps and that the retrapping occurs via the delocalized bands. At high-irradiation beta-doses, aggregate defect centres which significantly alter the TL and OSL properties, are induced in the material. The induced aggregate centres get completely obliterated by heating a sample to 700°C. The radiation-induced defects cause the main TL peak to shift towards higher temperatures, increase its FWHM, reduce its maximum intensity and cause an underestimation of both the activation energy and order of kinetics of the peak. On the other hand, the OSL response of the material is enhanced following a high-irradiation dose. During sample storage in the dark at ambient temperature, charges do migrate from the deep traps (donors) to the main and intermediate traps (acceptors) and that the major donor traps during this charge transfer phenomenon lie between 500-600°C.
- Full Text:
Comparing sequence and structure of falcipains and human homologs at prodomain and catalytic active site for malarial peptide-based inhibitor design:
- Musyoka, Thommas M, Njuguna, Joyce N, Tastan Bishop, Özlem
- Authors: Musyoka, Thommas M , Njuguna, Joyce N , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148392 , vital:38735 , DOI: 10.1101/381566
- Description: Falcipains are major cysteine proteases of Plasmodium falciparum involved in haemoglobin degradation and remain attractive anti-malarial drug targets. Several inhibitors against these proteases have been identified, yet none of them has been approved for malaria treatment. Other Plasmodium species also possess highly homologous proteins to falcipains. For selective therapeutic targeting, identification of sequence and structure differences with homologous human cathepsins is necessary. The substrate processing activity of these proteins is tightly controlled via a prodomain segment occluding the active site which is chopped under low pH conditions exposing the catalytic site. Current work characterizes these proteases to identify residues mediating the prodomain regulatory function for the design of peptide based anti-malarial inhibitors.
- Full Text:
- Authors: Musyoka, Thommas M , Njuguna, Joyce N , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148392 , vital:38735 , DOI: 10.1101/381566
- Description: Falcipains are major cysteine proteases of Plasmodium falciparum involved in haemoglobin degradation and remain attractive anti-malarial drug targets. Several inhibitors against these proteases have been identified, yet none of them has been approved for malaria treatment. Other Plasmodium species also possess highly homologous proteins to falcipains. For selective therapeutic targeting, identification of sequence and structure differences with homologous human cathepsins is necessary. The substrate processing activity of these proteins is tightly controlled via a prodomain segment occluding the active site which is chopped under low pH conditions exposing the catalytic site. Current work characterizes these proteases to identify residues mediating the prodomain regulatory function for the design of peptide based anti-malarial inhibitors.
- Full Text:
Comparison of physiological responses to high temperatures in juvenile and adult Cape Rockjumpers Chaetops frenatus
- Oswald, Krista N, Lee, Alan T K, Smit, Ben
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441559 , vital:73898 , https://doi.org/10.2989/00306525.2018.1509905
- Description: Concerns about climate change have led to an increase in studies on physiological mechanisms birds possess to cope with increasing temperatures. For range-restricted species such as Cape Rockjumpers Chaetops frenatus, whose population declines are correlated with habitat warming, we identified juvenile physiological responses to high temperature as a potential gap in current knowledge. We compared metabolic rate, evaporative water loss, evaporative cooling efficiency (calculated from evaporative water loss and resting metabolic rate) and body temperature in juveniles (n = 5) with adult birds (n = 10) to a ramped temperature profile (30–42 °C). Although juveniles exhibited no significant difference in cooling efficiency, they had higher evaporative water loss, resting metabolic rate and body temperature. This suggests that while juvenile birds show similar abilities to dissipate metabolic heat evaporatively, they face higher overall water and energy demands, and thus higher thermoregulatory costs in maintaining body temperature as overall temperatures continue to increase.
- Full Text:
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441559 , vital:73898 , https://doi.org/10.2989/00306525.2018.1509905
- Description: Concerns about climate change have led to an increase in studies on physiological mechanisms birds possess to cope with increasing temperatures. For range-restricted species such as Cape Rockjumpers Chaetops frenatus, whose population declines are correlated with habitat warming, we identified juvenile physiological responses to high temperature as a potential gap in current knowledge. We compared metabolic rate, evaporative water loss, evaporative cooling efficiency (calculated from evaporative water loss and resting metabolic rate) and body temperature in juveniles (n = 5) with adult birds (n = 10) to a ramped temperature profile (30–42 °C). Although juveniles exhibited no significant difference in cooling efficiency, they had higher evaporative water loss, resting metabolic rate and body temperature. This suggests that while juvenile birds show similar abilities to dissipate metabolic heat evaporatively, they face higher overall water and energy demands, and thus higher thermoregulatory costs in maintaining body temperature as overall temperatures continue to increase.
- Full Text:
Comparison of physiological responses to high temperatures in juvenile and adult Cape Rockjumpers Chaetops frenatus
- Oswald, Krista N, Lee, Alan T K, Smit, Ben
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448398 , vital:74727 , https://doi.org/10.2989/00306525.2018.1509905
- Description: Concerns about climate change have led to an increase in studies on physiological mechanisms birds possess to cope with increasing temperatures. For range-restricted species such as Cape Rockjumpers Chaetops frenatus, whose population declines are correlated with habitat warming, we identified juvenile physiological responses to high temperature as a potential gap in current knowledge. We compared metabolic rate, evaporative water loss, evaporative cooling efficiency (calculated from evaporative water loss and resting metabolic rate) and body temperature in juveniles (n = 5) with adult birds (n = 10) to a ramped temperature profile (30–42 °C). Although juveniles exhibited no significant difference in cooling efficiency, they had higher evaporative water loss, resting metabolic rate and body temperature. This suggests that while juvenile birds show similar abilities to dissipate metabolic heat evaporatively, they face higher overall water and energy demands, and thus higher thermoregulatory costs in maintaining body temperature as overall temperatures continue to increase.
- Full Text:
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448398 , vital:74727 , https://doi.org/10.2989/00306525.2018.1509905
- Description: Concerns about climate change have led to an increase in studies on physiological mechanisms birds possess to cope with increasing temperatures. For range-restricted species such as Cape Rockjumpers Chaetops frenatus, whose population declines are correlated with habitat warming, we identified juvenile physiological responses to high temperature as a potential gap in current knowledge. We compared metabolic rate, evaporative water loss, evaporative cooling efficiency (calculated from evaporative water loss and resting metabolic rate) and body temperature in juveniles (n = 5) with adult birds (n = 10) to a ramped temperature profile (30–42 °C). Although juveniles exhibited no significant difference in cooling efficiency, they had higher evaporative water loss, resting metabolic rate and body temperature. This suggests that while juvenile birds show similar abilities to dissipate metabolic heat evaporatively, they face higher overall water and energy demands, and thus higher thermoregulatory costs in maintaining body temperature as overall temperatures continue to increase.
- Full Text:
Confronting the Colonial Library: teaching Political Studies amidst calls for a decolonised curriculum
- Authors: Matthews, Sally
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142191 , vital:38057 , DOI: 10.1080/02589346.2018.1418204
- Description: This paper engages with Mudimbe's concept of the ‘colonial library’ with the aim of using this engagement to contribute to current debates about decolonising South African university curricula. The term ‘colonial library’ refers to the body of texts and epistemological order which construct Africa as a symbol of otherness and inferiority. Mudimbe shows that even the most determined attempts to resist the colonial library draw on this same epistemological order. This presents a profound challenge for attempts to decolonise university curricula as it suggests that the colonial library's reach extends into attempts to dismantle it. In response to this challenge, I discuss ways in which we can oppose epistemological ethnocentrism and argue that we need to be open to the possibility of the emancipatory reappropriation of aspects of the colonial library. The paper concludes by relating the foregoing discussion to the South African political studies classroom.
- Full Text:
- Authors: Matthews, Sally
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142191 , vital:38057 , DOI: 10.1080/02589346.2018.1418204
- Description: This paper engages with Mudimbe's concept of the ‘colonial library’ with the aim of using this engagement to contribute to current debates about decolonising South African university curricula. The term ‘colonial library’ refers to the body of texts and epistemological order which construct Africa as a symbol of otherness and inferiority. Mudimbe shows that even the most determined attempts to resist the colonial library draw on this same epistemological order. This presents a profound challenge for attempts to decolonise university curricula as it suggests that the colonial library's reach extends into attempts to dismantle it. In response to this challenge, I discuss ways in which we can oppose epistemological ethnocentrism and argue that we need to be open to the possibility of the emancipatory reappropriation of aspects of the colonial library. The paper concludes by relating the foregoing discussion to the South African political studies classroom.
- Full Text:
Conjugation of isoniazid to a zinc phthalocyanine via hydrazone linkage for pH-dependent liposomal controlled release
- Nkanga, Christian I, Krause, Rui W M
- Authors: Nkanga, Christian I , Krause, Rui W M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194992 , vital:45517 , xlink:href="https://doi.org/10.1007/s13204-018-0776-y"
- Description: Tuberculosis (TB) remains the leading cause of mortality from infectious diseases. Extended TB treatment and frequent adverse effects, due to poor bioavailability of anti-tubercular drugs (ATBDs), represent the main rationales behind liposomal encapsulation for controlled delivery. Liposomes have been reported as potential vehicles for targeted delivery of ATBDs due to their rapid uptake by macrophages, which are known as the main host cells for TB causative agent (Mycobacterium tuberculosis). Additionally, the need for controlled release of ATBDs arises because leakage is part of the key liposome challenges for hydrophilic compounds like isoniazid (INH). In this study, INH was conjugated to a highly hydrophobic photosensitizer, zinc (II) phthalocyanine (PC), through hydrazone bonding. The obtained conjugate (PC–INH) was encapsulated in liposomes by film hydration method. PC–INH loaded liposomes (PILs) were characterized using dynamic light scattering, transmission electron microscopy, energy-dispersive X-ray spectrometry and UV–Vis absorption spectrometry, which was used also for estimation of encapsulation efficiency (î). INH release was evaluated in different pH media using dialysis. Particle size, zeta potential and î of PILs were about 506 nm, − 55 mV and 72%, respectively. Over 12 h, PILs exhibited 22, 41, 97 and 100% of INH, respectively, released in pH 7.4, 6.4, 5.4 and 4.4 media. This pH-dependent behavior is attractive for site-specific delivery. These findings suggest the conjugation of chemotherapeutics to phthalocyanines using pH-labile linkages as a potential strategy for liposomal controlled release.
- Full Text:
- Authors: Nkanga, Christian I , Krause, Rui W M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194992 , vital:45517 , xlink:href="https://doi.org/10.1007/s13204-018-0776-y"
- Description: Tuberculosis (TB) remains the leading cause of mortality from infectious diseases. Extended TB treatment and frequent adverse effects, due to poor bioavailability of anti-tubercular drugs (ATBDs), represent the main rationales behind liposomal encapsulation for controlled delivery. Liposomes have been reported as potential vehicles for targeted delivery of ATBDs due to their rapid uptake by macrophages, which are known as the main host cells for TB causative agent (Mycobacterium tuberculosis). Additionally, the need for controlled release of ATBDs arises because leakage is part of the key liposome challenges for hydrophilic compounds like isoniazid (INH). In this study, INH was conjugated to a highly hydrophobic photosensitizer, zinc (II) phthalocyanine (PC), through hydrazone bonding. The obtained conjugate (PC–INH) was encapsulated in liposomes by film hydration method. PC–INH loaded liposomes (PILs) were characterized using dynamic light scattering, transmission electron microscopy, energy-dispersive X-ray spectrometry and UV–Vis absorption spectrometry, which was used also for estimation of encapsulation efficiency (î). INH release was evaluated in different pH media using dialysis. Particle size, zeta potential and î of PILs were about 506 nm, − 55 mV and 72%, respectively. Over 12 h, PILs exhibited 22, 41, 97 and 100% of INH, respectively, released in pH 7.4, 6.4, 5.4 and 4.4 media. This pH-dependent behavior is attractive for site-specific delivery. These findings suggest the conjugation of chemotherapeutics to phthalocyanines using pH-labile linkages as a potential strategy for liposomal controlled release.
- Full Text:
Conservation and human livelihoods at the crossroads: Local needs and knowledge in the management of Arabuko Sokoke Forest
- Chiawo, David O, Kombe, Wellington N, Craig, Adrian J F K
- Authors: Chiawo, David O , Kombe, Wellington N , Craig, Adrian J F K
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448843 , vital:74765 , https://doi.org/10.1111/aje.12462
- Description: Arabuko Sokoke Forest is the largest remaining single block of indigenous dry coastal tropical forest in Eastern Africa. Households within a 5 km buffer zone depend heavily on the forest for their livelihood needs, and the pressure on forest resources is on the increase. In May 2015, 109 households were interviewed on resources they obtain from the forest, in terms of the self‐reported level of monthly income. We found household income and farm size significantly positively correlated with benefits from the forest, highlighting the possible influence of household wealth in exploiting forest resources. A large proportion of households (32%) had limited knowledge of local birds, while human–bird conflict was reported by 44% of the households. While many households were keen to participate in conservation projects that maintain the forest, 44% had no knowledge of the forest management plan, and 60% of those interviewed had no idea of how forest zones were designated for particular activities. Drivers for local community participation in conservation projects appear to be sustainable income and fulfilment of basic household needs.
- Full Text:
- Authors: Chiawo, David O , Kombe, Wellington N , Craig, Adrian J F K
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448843 , vital:74765 , https://doi.org/10.1111/aje.12462
- Description: Arabuko Sokoke Forest is the largest remaining single block of indigenous dry coastal tropical forest in Eastern Africa. Households within a 5 km buffer zone depend heavily on the forest for their livelihood needs, and the pressure on forest resources is on the increase. In May 2015, 109 households were interviewed on resources they obtain from the forest, in terms of the self‐reported level of monthly income. We found household income and farm size significantly positively correlated with benefits from the forest, highlighting the possible influence of household wealth in exploiting forest resources. A large proportion of households (32%) had limited knowledge of local birds, while human–bird conflict was reported by 44% of the households. While many households were keen to participate in conservation projects that maintain the forest, 44% had no knowledge of the forest management plan, and 60% of those interviewed had no idea of how forest zones were designated for particular activities. Drivers for local community participation in conservation projects appear to be sustainable income and fulfilment of basic household needs.
- Full Text:
Constructing an EMF radiation Hygeia framework and model to demonstrate a public interest override
- Authors: Lech, James Chrystopher
- Date: 2018
- Subjects: Electromagnetic fields , Electromagnetic fields -- Health aspects , Electromagnetic fields -- Measurement , Public interest , Radiation -- Measurement , HYGEIA , Promotion of Access to Information Act (PAIA)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58695 , vital:27364
- Description: Scientific views on EMF radiation dosimetry and models increasingly suggest that even a tiny increase in the incidence of diseases resulting from exposure to EMF radiation could have broad¹ implications for public health, social accounting and the economy. In South Africa (SA) there is no national EMF radiation exposure protection standard, statutory monitoring or regulations. Multinational High Court deliberations indicate the need for public interest EMF radiation exposure protection standards in South Africa. Domestic citizens, academics, as well as regulatory and legislative practitioners, are unable to effectively monitor and investigate EMF radiation exposure emissions from infrastructure sources, because industries refuse to provide the required data. Industries have, since 2003, continually obstructed access to the data and the establishment of a national EMF radiation standard, citing that it would be in conflict with their strategic economic interests. The demonstration of a public interest override (PIO) function is legislatively required to gain access to the required data. This study constructed (1) a framework and (2) a model to perform test simulations against the (3) PIO criteria to demonstrate a PIO function and tested one PIO simulation scenario. Testing the PIO scenario firstly required the construction of a public interest framework, drawing input from multiple disciplines. The framework literature review used systematic case law and scientific-technical analysis whilst the framework science sought to understand the connections, feedbacks, and trajectories that occur as a result of natural and human system processes and exchanges. The EMF radiation exposure system functions to support human wellbeing needs and to explore the benefits and losses associated with alternative futures with the goal to uncover the current and future limits thereof. In the second instance a HYGEIA² model was selected as a base investigation and forecast simulation tool. The study had to uncover the key attributes and parameters necessary to construct and to run successful EMF radiation exposure simulations. Thereafter the HYGEIA model was modified to specifically identify and evaluate EMF radiation exposure hazard conditions. Through subsequent simulation runs, the constructed framework was then tested. Requested anthroposphere information was synthesized within a systems model to forecast ecosystem services and human-use dynamics under alternative scenarios. The simulation used the model, the model references and the framework for guidelines, thus allowing multiple simulation / demonstration runs for different contexts or scenarios. The third step was the construction of a PIO checklist which guides criteria testing and provides a means of gaining pertinent information for further studies, based on this dissertation. Framework EMF radiation policy inputs into the model were intersected with identified vulnerable area facilities which were selected based on international criteria. The research output revealed potential EMF radiation violations which served as system feedback inputs in support of a demonstrated PIO function. The research recommends that the identified EMF radiation exposure violations of public health undergo a Promotion of Access to Information Act (PAIA) judicial review process to confirm the research findings. The judicial qualification of a PAIA PIO function of ‘substances released into the environment’ and ‘public safety or environmental risk’ would enable access to EMF radiation emissions data essential to future studies.
- Full Text:
- Authors: Lech, James Chrystopher
- Date: 2018
- Subjects: Electromagnetic fields , Electromagnetic fields -- Health aspects , Electromagnetic fields -- Measurement , Public interest , Radiation -- Measurement , HYGEIA , Promotion of Access to Information Act (PAIA)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58695 , vital:27364
- Description: Scientific views on EMF radiation dosimetry and models increasingly suggest that even a tiny increase in the incidence of diseases resulting from exposure to EMF radiation could have broad¹ implications for public health, social accounting and the economy. In South Africa (SA) there is no national EMF radiation exposure protection standard, statutory monitoring or regulations. Multinational High Court deliberations indicate the need for public interest EMF radiation exposure protection standards in South Africa. Domestic citizens, academics, as well as regulatory and legislative practitioners, are unable to effectively monitor and investigate EMF radiation exposure emissions from infrastructure sources, because industries refuse to provide the required data. Industries have, since 2003, continually obstructed access to the data and the establishment of a national EMF radiation standard, citing that it would be in conflict with their strategic economic interests. The demonstration of a public interest override (PIO) function is legislatively required to gain access to the required data. This study constructed (1) a framework and (2) a model to perform test simulations against the (3) PIO criteria to demonstrate a PIO function and tested one PIO simulation scenario. Testing the PIO scenario firstly required the construction of a public interest framework, drawing input from multiple disciplines. The framework literature review used systematic case law and scientific-technical analysis whilst the framework science sought to understand the connections, feedbacks, and trajectories that occur as a result of natural and human system processes and exchanges. The EMF radiation exposure system functions to support human wellbeing needs and to explore the benefits and losses associated with alternative futures with the goal to uncover the current and future limits thereof. In the second instance a HYGEIA² model was selected as a base investigation and forecast simulation tool. The study had to uncover the key attributes and parameters necessary to construct and to run successful EMF radiation exposure simulations. Thereafter the HYGEIA model was modified to specifically identify and evaluate EMF radiation exposure hazard conditions. Through subsequent simulation runs, the constructed framework was then tested. Requested anthroposphere information was synthesized within a systems model to forecast ecosystem services and human-use dynamics under alternative scenarios. The simulation used the model, the model references and the framework for guidelines, thus allowing multiple simulation / demonstration runs for different contexts or scenarios. The third step was the construction of a PIO checklist which guides criteria testing and provides a means of gaining pertinent information for further studies, based on this dissertation. Framework EMF radiation policy inputs into the model were intersected with identified vulnerable area facilities which were selected based on international criteria. The research output revealed potential EMF radiation violations which served as system feedback inputs in support of a demonstrated PIO function. The research recommends that the identified EMF radiation exposure violations of public health undergo a Promotion of Access to Information Act (PAIA) judicial review process to confirm the research findings. The judicial qualification of a PAIA PIO function of ‘substances released into the environment’ and ‘public safety or environmental risk’ would enable access to EMF radiation emissions data essential to future studies.
- Full Text:
Contesting sexual violence policies in higher education: the case of Rhodes University
- Macleod, Catriona I, Böhmke, Werner, Barker, Kim, Mavuso, Jabulile M-J J, Chiweshe, Malvern T
- Authors: Macleod, Catriona I , Böhmke, Werner , Barker, Kim , Mavuso, Jabulile M-J J , Chiweshe, Malvern T
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444275 , vital:74212 , xlink:href="https://www.emerald.com/insight/content/doi/10.1108/JACPR-05-2017-0295/full/html"
- Description: – In April 2016, students at Rhodes University brought the institution to a standstill as they protested the University’s sexual violence policies and procedures, as well as the “rape culture” that pervades social structures. In response, a Sexual Violence Task Team (SVTT) was formed in an open, participatory, and transparent process. Members of the University community were invited to comment on drafts of the SVTT document. The purpose of this paper is to outline the contestations – arising from both the establishment of the task team and the inputs from University members to drafts of the document – that surfaced concerning managing sexual violence on campuses and sexual offences policies.
- Full Text:
- Authors: Macleod, Catriona I , Böhmke, Werner , Barker, Kim , Mavuso, Jabulile M-J J , Chiweshe, Malvern T
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444275 , vital:74212 , xlink:href="https://www.emerald.com/insight/content/doi/10.1108/JACPR-05-2017-0295/full/html"
- Description: – In April 2016, students at Rhodes University brought the institution to a standstill as they protested the University’s sexual violence policies and procedures, as well as the “rape culture” that pervades social structures. In response, a Sexual Violence Task Team (SVTT) was formed in an open, participatory, and transparent process. Members of the University community were invited to comment on drafts of the SVTT document. The purpose of this paper is to outline the contestations – arising from both the establishment of the task team and the inputs from University members to drafts of the document – that surfaced concerning managing sexual violence on campuses and sexual offences policies.
- Full Text:
Contesting the nature of young pregnant and mothering women: Critical healthcare nexus research, ethics committees, and healthcare institutions
- Feltham-King, Tracey, Bomela, Yolisa, Macleod, Catriona I
- Authors: Feltham-King, Tracey , Bomela, Yolisa , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434199 , vital:73038 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_5
- Description: In this chapter we describe how systemic contradictions complicate ethical site entry and data collection in critical research. We present our ethnographic research within South African antenatal and postnatal clinics as an example. Pregnant and mothering young women are subject to diverging views of minors in different state-produced policies and legislation. In addition, we encountered discrepancies between our research aims and assumptions made by the University Ethical Standards Committee, managers, healthcare providers, teenaged participants, and other service users. These complexities have implications for ethical engagement of researchers and call for nuanced means of data collection and analysis. We discuss how critical researchers can mitigate social injustice by questioning entrenched ways of thinking about participants and negotiating the contradictory positionings of self and others.
- Full Text:
- Authors: Feltham-King, Tracey , Bomela, Yolisa , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434199 , vital:73038 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_5
- Description: In this chapter we describe how systemic contradictions complicate ethical site entry and data collection in critical research. We present our ethnographic research within South African antenatal and postnatal clinics as an example. Pregnant and mothering young women are subject to diverging views of minors in different state-produced policies and legislation. In addition, we encountered discrepancies between our research aims and assumptions made by the University Ethical Standards Committee, managers, healthcare providers, teenaged participants, and other service users. These complexities have implications for ethical engagement of researchers and call for nuanced means of data collection and analysis. We discuss how critical researchers can mitigate social injustice by questioning entrenched ways of thinking about participants and negotiating the contradictory positionings of self and others.
- Full Text:
Contrasting responses in the niches of two coral reef herbivores along a gradient of habitat disturbance in the Spermonde Archipelago, Indonesia
- Plass-Johnson, Jeremiah G, Bednarz, Vanessa N, Hill, Jaclyn M, Jompa, Jamaluddin, Ferse, Sebastian C A, Teichberg, Mirta
- Authors: Plass-Johnson, Jeremiah G , Bednarz, Vanessa N , Hill, Jaclyn M , Jompa, Jamaluddin , Ferse, Sebastian C A , Teichberg, Mirta
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69135 , vital:29398 , hhttps://doi.org/10.3389/fmars.2018.00032
- Description: Habitat modification of coral reefs is becoming increasingly common due to increases in coastal urban populations. Coral reef fish are highly dependent on benthic habitat; however, information on species-specific responses to habitat change, in particular with regard to trophic strategies, remains scarce. This study identifies variation in the trophic niches of two herbivorous coral reef fishes with contrasting trophic strategies, using Stable Isotopes Bayesian Ellipses in R, along a spatial gradient of changing coral reef habitats. In the parrotfish Chlorurus bleekeri, a roving consumer, the range of δ15N and δ13C and their niche area displayed significant relationships with the amount of rubble in the habitat. In contrast, the farming damselfish, Dischistodus prosopotaenia, showed a narrow range of both δ15N and δ13C, displaying little change in niche parameters among sites. This may indicate that parrotfish vary their feeding according to habitat, while the damselfish continue to maintain their turf and invertebrate resources. Assessing isotopic niches may help to better understand the specific trophic responses to change in the environment. Furthermore, the use of isotopic niches underlines the utility of stable isotopes in studying the potential impacts of environmental change on feeding ecology.
- Full Text:
- Authors: Plass-Johnson, Jeremiah G , Bednarz, Vanessa N , Hill, Jaclyn M , Jompa, Jamaluddin , Ferse, Sebastian C A , Teichberg, Mirta
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69135 , vital:29398 , hhttps://doi.org/10.3389/fmars.2018.00032
- Description: Habitat modification of coral reefs is becoming increasingly common due to increases in coastal urban populations. Coral reef fish are highly dependent on benthic habitat; however, information on species-specific responses to habitat change, in particular with regard to trophic strategies, remains scarce. This study identifies variation in the trophic niches of two herbivorous coral reef fishes with contrasting trophic strategies, using Stable Isotopes Bayesian Ellipses in R, along a spatial gradient of changing coral reef habitats. In the parrotfish Chlorurus bleekeri, a roving consumer, the range of δ15N and δ13C and their niche area displayed significant relationships with the amount of rubble in the habitat. In contrast, the farming damselfish, Dischistodus prosopotaenia, showed a narrow range of both δ15N and δ13C, displaying little change in niche parameters among sites. This may indicate that parrotfish vary their feeding according to habitat, while the damselfish continue to maintain their turf and invertebrate resources. Assessing isotopic niches may help to better understand the specific trophic responses to change in the environment. Furthermore, the use of isotopic niches underlines the utility of stable isotopes in studying the potential impacts of environmental change on feeding ecology.
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