Participatory mapping, learning and change in the context of biocultural diversity and resilience
- Authors: Ali, Million Belay
- Date: 2012
- Subjects: Biodiversity conservation -- Research -- Ethiopia Cultural pluralism -- Research -- Ethiopia Ethnopsychology -- Research -- Ethiopia Adult education -- Research -- Ethiopia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1689 , http://hdl.handle.net/10962/d1003572
- Description: This study set out to investigate the learning and change that emerged in and through participatory mapping in the context of biocultural diversity and resilience in rural Ethiopia. It did this through examining the learning and agency emerging from three participatory mapping practices (Participatory 3 Dimensional Modelling, sketch mapping and eco-cultural calendars) using two case study sites, located in the Bale Mountains and the Foata Mountains in Ethiopia, and honing in on in-depth reflective processes in two community contexts located within the broader case study sites, namely Horo Soba, Dinsho wereda in Bale; and Telecho, in Wolmera wereda, in the Foata Mountain complex. This study tried to answer three research questions related to participatory mapping: its role in mobilizing knowledge related to biocultural landscape, its role in learning and change, and its value in building resilience. The study used qualitative case study research methodology underpinned by critical realist philosophy, and used photographic ‘cues’ to structure the reporting on the cases. It used four categories of analysis: biocultural diversity, educational processes, learning and agency, in the first instance to report on the interactions associated with the participatory mapping practices as they emerged in the two case study sites. This was followed by in-depth analysis and interpretation of participatory mapping and biocultural diversity, as well as participatory mapping and learning, with an emphasis on acquisition, meaning making and identity formation processes. The in-depth analysis drew on social and learning theory, and theory of biocultural diversity and social-ecological resilience. The study also included analysis of broader change processes that were related to and emerged from the social interactions in the mapping activities, and the resultant morphogenesis (change), showing that morphogenesis, while broadly temporal, is not linear, and involves ‘little iterative morphogenic cycles’. These insights were then used to interpret how participatory mapping may contribute to resilience building in a context where social-ecological resilience is increasingly required, such as the two case study sites, where socialecological degradation is highly visible and is occurring rapidly. The study’s contribution to new knowledge lies in relation to the role of participatory mapping in facilitating learning, agency and change which, to date, appears to be under-theorised and under-developed in the participatory mapping and environmental education literature. As such, the study findings provide in-depth insight into how participatory mapping methodologies may ‘work in the world’, in contexts such as those presented in the two cases under study. It has tried to demonstrate how participatory mapping has managed to mobilize knowledge related to biocultural diversity, facilitated the acquisition of knowledge and helped members of the community to engage in meaning making activities relevant to their biocultural landscape and renegotiate their identity within the wider community context. It has also shown that dissonance is an important dynamic in the learning process; and that morphogenesis (or change) occurs over time, but also in smaller cycles that interact at different levels; and that participatory mapping cannot, by itself mobilise significant structural change, at least in the short term. It has also shown, however, that learning and the desire for change can emerge from participatory mapping processes, and that this can be utilized to adapt to the changing socio-ecological environments, potentially contributing to longer term resilience of social-ecological systems.
- Full Text:
- Authors: Ali, Million Belay
- Date: 2012
- Subjects: Biodiversity conservation -- Research -- Ethiopia Cultural pluralism -- Research -- Ethiopia Ethnopsychology -- Research -- Ethiopia Adult education -- Research -- Ethiopia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1689 , http://hdl.handle.net/10962/d1003572
- Description: This study set out to investigate the learning and change that emerged in and through participatory mapping in the context of biocultural diversity and resilience in rural Ethiopia. It did this through examining the learning and agency emerging from three participatory mapping practices (Participatory 3 Dimensional Modelling, sketch mapping and eco-cultural calendars) using two case study sites, located in the Bale Mountains and the Foata Mountains in Ethiopia, and honing in on in-depth reflective processes in two community contexts located within the broader case study sites, namely Horo Soba, Dinsho wereda in Bale; and Telecho, in Wolmera wereda, in the Foata Mountain complex. This study tried to answer three research questions related to participatory mapping: its role in mobilizing knowledge related to biocultural landscape, its role in learning and change, and its value in building resilience. The study used qualitative case study research methodology underpinned by critical realist philosophy, and used photographic ‘cues’ to structure the reporting on the cases. It used four categories of analysis: biocultural diversity, educational processes, learning and agency, in the first instance to report on the interactions associated with the participatory mapping practices as they emerged in the two case study sites. This was followed by in-depth analysis and interpretation of participatory mapping and biocultural diversity, as well as participatory mapping and learning, with an emphasis on acquisition, meaning making and identity formation processes. The in-depth analysis drew on social and learning theory, and theory of biocultural diversity and social-ecological resilience. The study also included analysis of broader change processes that were related to and emerged from the social interactions in the mapping activities, and the resultant morphogenesis (change), showing that morphogenesis, while broadly temporal, is not linear, and involves ‘little iterative morphogenic cycles’. These insights were then used to interpret how participatory mapping may contribute to resilience building in a context where social-ecological resilience is increasingly required, such as the two case study sites, where socialecological degradation is highly visible and is occurring rapidly. The study’s contribution to new knowledge lies in relation to the role of participatory mapping in facilitating learning, agency and change which, to date, appears to be under-theorised and under-developed in the participatory mapping and environmental education literature. As such, the study findings provide in-depth insight into how participatory mapping methodologies may ‘work in the world’, in contexts such as those presented in the two cases under study. It has tried to demonstrate how participatory mapping has managed to mobilize knowledge related to biocultural diversity, facilitated the acquisition of knowledge and helped members of the community to engage in meaning making activities relevant to their biocultural landscape and renegotiate their identity within the wider community context. It has also shown that dissonance is an important dynamic in the learning process; and that morphogenesis (or change) occurs over time, but also in smaller cycles that interact at different levels; and that participatory mapping cannot, by itself mobilise significant structural change, at least in the short term. It has also shown, however, that learning and the desire for change can emerge from participatory mapping processes, and that this can be utilized to adapt to the changing socio-ecological environments, potentially contributing to longer term resilience of social-ecological systems.
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Patrick Hayes. JM Coetzee and the Novel: writing and politics after Beckett
- Authors: Marais, Mike
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144220 , vital:38322 , DOI: 10.1093/res/hgs014
- Description: According to Patrick Hayes, J. M. Coetzee's fiction, on a thematic level, ‘repeatedly suggests that the condition of modernity is made up of competing, equally important, and yet incommensurate ways of imagining the good community’ (p. 4). The first of these imaginings is grounded in the Kantian notion that the human individual is a rational and autonomous agent, and that it is precisely his or her rational autonomy, and capacity to direct life through neutral principles that commands the respect and recognition of other individuals. As is evident in its emphasis on rationality, this politic of equal dignity and recognition is universalistic in its claims. In contrast, the second imagining of community is based on the recognition of cultural specificity, and the argument that freedom and equal recognition are only possible through a revision of deleterious cultural stereotypes. In its terms, the good community ‘must be founded on the recognition, and active fostering of cultural particularity’ (p. 12). This politic of difference is highly suspicious of the universalizing claims of the politic of dignity, arguing that its appeal to equal dignity is itself a form of particularism masquerading as universalism.
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- Authors: Marais, Mike
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144220 , vital:38322 , DOI: 10.1093/res/hgs014
- Description: According to Patrick Hayes, J. M. Coetzee's fiction, on a thematic level, ‘repeatedly suggests that the condition of modernity is made up of competing, equally important, and yet incommensurate ways of imagining the good community’ (p. 4). The first of these imaginings is grounded in the Kantian notion that the human individual is a rational and autonomous agent, and that it is precisely his or her rational autonomy, and capacity to direct life through neutral principles that commands the respect and recognition of other individuals. As is evident in its emphasis on rationality, this politic of equal dignity and recognition is universalistic in its claims. In contrast, the second imagining of community is based on the recognition of cultural specificity, and the argument that freedom and equal recognition are only possible through a revision of deleterious cultural stereotypes. In its terms, the good community ‘must be founded on the recognition, and active fostering of cultural particularity’ (p. 12). This politic of difference is highly suspicious of the universalizing claims of the politic of dignity, arguing that its appeal to equal dignity is itself a form of particularism masquerading as universalism.
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Peat formation in the context of the development of the Mkuze floodplain on the coastal plain of Maputaland, South Africa:
- Ellery, William F N, Grenfell, Suzanne E, Grenfell, Michael C, Humphries, M S, Barnes, K, Dahlberg, S, Kindness, A
- Authors: Ellery, William F N , Grenfell, Suzanne E , Grenfell, Michael C , Humphries, M S , Barnes, K , Dahlberg, S , Kindness, A
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144354 , vital:38338 , DOI: 10.1016/j.geomorph.2011.11.009
- Description: This paper examines the geomorphological and sedimentological development of blocked-valley lakes in the Mkuze floodplain on the coastal plain of Maputaland, northern KwaZulu-Natal, South Africa. Blocked tributary valley lakes north of the floodplain become progressively shorter, broader, and less linear toward the eastern (downstream) end of the east–west oriented Mkuze floodplain. Clastic sediment forms surface sedimentary fill in tributary valleys in the west, while peat predominates tributary valley fill in the east. Two contrasting adjacent tributary valleys were examined, the more western Yengweni dominated by clastic sediment at the surface, and the more eastern Totweni with peat.
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- Authors: Ellery, William F N , Grenfell, Suzanne E , Grenfell, Michael C , Humphries, M S , Barnes, K , Dahlberg, S , Kindness, A
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144354 , vital:38338 , DOI: 10.1016/j.geomorph.2011.11.009
- Description: This paper examines the geomorphological and sedimentological development of blocked-valley lakes in the Mkuze floodplain on the coastal plain of Maputaland, northern KwaZulu-Natal, South Africa. Blocked tributary valley lakes north of the floodplain become progressively shorter, broader, and less linear toward the eastern (downstream) end of the east–west oriented Mkuze floodplain. Clastic sediment forms surface sedimentary fill in tributary valleys in the west, while peat predominates tributary valley fill in the east. Two contrasting adjacent tributary valleys were examined, the more western Yengweni dominated by clastic sediment at the surface, and the more eastern Totweni with peat.
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Penumbra
- Authors: Mahlangu, Songeziwe
- Date: 2012
- Subjects: South African fiction (English) -- 21st century , Fiction -- Social aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5979 , http://hdl.handle.net/10962/d1015207
- Description: After failing his Post Graduate Diploma in Accounting Mangaliso Zolo takes an office job at a large insurance company in Cape Town. Anonymous and overlooked in a vast bureaucracy but with a pay check promising happiness and security, he slides into a series of personal crises that test his grip on what he believes in. When at his lowest ebb he leaves his job, grabs his bible and hits the streets his world closes in on him and he is eventually confined to a psychiatric hospital. Penumbra is a novel that explores the liminal area between faith and avarice, sanity and madness, modernity and tradition, friendship and enmity. It is set in contemporary South Africa, a society defined by alienation and excess.
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- Authors: Mahlangu, Songeziwe
- Date: 2012
- Subjects: South African fiction (English) -- 21st century , Fiction -- Social aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5979 , http://hdl.handle.net/10962/d1015207
- Description: After failing his Post Graduate Diploma in Accounting Mangaliso Zolo takes an office job at a large insurance company in Cape Town. Anonymous and overlooked in a vast bureaucracy but with a pay check promising happiness and security, he slides into a series of personal crises that test his grip on what he believes in. When at his lowest ebb he leaves his job, grabs his bible and hits the streets his world closes in on him and he is eventually confined to a psychiatric hospital. Penumbra is a novel that explores the liminal area between faith and avarice, sanity and madness, modernity and tradition, friendship and enmity. It is set in contemporary South Africa, a society defined by alienation and excess.
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Perceptions and values of local landscapes: implications for the conservation of biocultural diversity and intangible heritage
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141442 , vital:37972 , ISBN 9789086867493 , DOI: 10.3920/978-90-8686-749-3_10
- Description: South Africa is widely recognised as a highly diverse country with regard to its people, culture, landscapes, biological resources and ecology. The importance of policies on protecting cultural diversity and how they relate to the environment is only just emerging at an international level, but in South African we find there is a complete lack of institutional support for rural communities’ attachment to local landscapes. The main objective of this case study is to improve our understanding of the meanings and values that Xhosa people (amaXhosa) of the Eastern Cape Province of South Africa attach to their natural landscapes. It is clear that the amaXhosa are still intrinsically connected to their natural environment, in particular the thicket biome that is called ihlathi yesiXhosa (Xhosa forest). Access to places and spaces within the natural environment provides a sense of wellbeing, a link to ancestral spirits, a location for religious rituals, plus a wealth of culturallyinspired uses of specific species and sacred places in the landscape. We suggest that local cultural values could be incorporated into the formal conservation process.
- Full Text:
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141442 , vital:37972 , ISBN 9789086867493 , DOI: 10.3920/978-90-8686-749-3_10
- Description: South Africa is widely recognised as a highly diverse country with regard to its people, culture, landscapes, biological resources and ecology. The importance of policies on protecting cultural diversity and how they relate to the environment is only just emerging at an international level, but in South African we find there is a complete lack of institutional support for rural communities’ attachment to local landscapes. The main objective of this case study is to improve our understanding of the meanings and values that Xhosa people (amaXhosa) of the Eastern Cape Province of South Africa attach to their natural landscapes. It is clear that the amaXhosa are still intrinsically connected to their natural environment, in particular the thicket biome that is called ihlathi yesiXhosa (Xhosa forest). Access to places and spaces within the natural environment provides a sense of wellbeing, a link to ancestral spirits, a location for religious rituals, plus a wealth of culturallyinspired uses of specific species and sacred places in the landscape. We suggest that local cultural values could be incorporated into the formal conservation process.
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Perceptions of commerce graduates from a selected higher education institution
- Authors: Kaliika, Michael
- Date: 2012
- Subjects: Education, Higher -- Curricula -- South Africa -- Evaluation Business education -- Curricula -- South Africa -- Evaluation Business education graduates -- South Africa -- Attitudes
- Type: Thesis , Masters , MCom
- Identifier: vital:1188 , http://hdl.handle.net/10962/d1004358
- Description: The role of higher education in developing human capital and contributing to economic growth, competitive advantage and societal progress of any country is well documented. The direct link between the economic performance of a country and the level of education of its citizens cannot be repudiated. Furthermore, the demands of a growing economy, governmental pressure and the competitive international business environment have put pressure on South African businesses. This is aggravated by a “skills crisis” and the need to deliver more goods and services to increasingly more diverse customers. There is consensus amongst experts that the shortage of skills and high-level managerial human resources in South Africa constitute a major threat to the country’s future economic development and productivity growth. As the business world becomes increasingly sophisticated and challenging, so does the need to continuously review and assess the business qualifications that equip managers to cope with the challenges facing them. The competencies that come with a Commerce degree are relevant in every corner of society from managing successful private companies, public organisations, for governments to be able to contribute to the greatest good of society, to socially effective not- for- profit organisations. Despite the importance of a degree in Commerce there are some criticisms about the degree and Commerce graduates. The problem statement of this study is therefore vested in the continuum of praise and criticisms of Commerce graduates and the Commerce curriculum and, the reported imbalances between higher education institutions and the needs of the labour market. The question is whether such praise and criticisms are justified and whether higher education institutions specifically meet the requirements and expectations of both the graduates themselves and of business practice. The primary research objective of this study was, therefore, to obtain the opinions of Commerce graduates and Commerce graduate employers on the overall perception of Commerce graduates produced by a prominent HEI in the Eastern Cape Province in South iv Africa. To achieve this objective and based on in-depth analysis of secondary sources, two independent empirical surveys, aimed at two population strata were conducted, namely: • The Commerce graduates with known email addresses (N = 1 870) were extracted from the HEI’s alumni database. A total of 231 usable questionnaires were received from these Commerce graduates. • The employers with known addresses (N = 85) were extracted from the selected HEIs Career Centre database. A total of 47 usable questionnaires were received from the employers of the Commerce graduates. The main findings in this research pertain to aspects concerning core courses in the Commerce curriculum offered by the selected HEI, management skills and traits as required in the work environment, commerce curriculum outcomes and perceived experience as a student in the Faculty of Commerce at the selected HEI and Employer perceptions on the profile of the Commerce graduate. In this regard, the main findings are therefore summarised below: • Both graduates and employers assigned high relative importance scores to seventeen of the 19 core courses, supporting the multi-functionary interdisciplinary approach to the Commerce curriculum. Concerns were expressed by the Commerce graduates with the quality of tuition they had received in most of the core courses. Likewise, employers were not always satisfied with the Commerce graduates’ proficiency in some of the core courses, relative to the importance of core courses for running a business. • The Commerce graduates and employers strongly endorsed and supported the importance of the 43 management skills and traits in the work environment. Commerce graduates expressed concerns about the extent to which their management skills and traits had been developed through tuition. Concerns about the proficiency of the Commerce graduates in all the management skills and traits, relative to the importance in the work place, were conveyed by the employers. • On average the perceptions on the outcome of studies in the Faculty of Commerce were very highly regarded by the Commerce graduates. The highest mean score was for the item “Studying in the Faculty of Commerce contributed to an increase in my knowledge and abilities.”• The perceived experience of Commerce graduates as students in the Faculty of Commerce at the selected HEI was very highly regarded, implying that the selected HEI was meeting the expectations of its Commerce graduates. • Employer perceptions of what would constitute an ideal Commerce graduate were not fully met by the profile of the actual Commerce graduate from the selected HEI.
- Full Text:
- Authors: Kaliika, Michael
- Date: 2012
- Subjects: Education, Higher -- Curricula -- South Africa -- Evaluation Business education -- Curricula -- South Africa -- Evaluation Business education graduates -- South Africa -- Attitudes
- Type: Thesis , Masters , MCom
- Identifier: vital:1188 , http://hdl.handle.net/10962/d1004358
- Description: The role of higher education in developing human capital and contributing to economic growth, competitive advantage and societal progress of any country is well documented. The direct link between the economic performance of a country and the level of education of its citizens cannot be repudiated. Furthermore, the demands of a growing economy, governmental pressure and the competitive international business environment have put pressure on South African businesses. This is aggravated by a “skills crisis” and the need to deliver more goods and services to increasingly more diverse customers. There is consensus amongst experts that the shortage of skills and high-level managerial human resources in South Africa constitute a major threat to the country’s future economic development and productivity growth. As the business world becomes increasingly sophisticated and challenging, so does the need to continuously review and assess the business qualifications that equip managers to cope with the challenges facing them. The competencies that come with a Commerce degree are relevant in every corner of society from managing successful private companies, public organisations, for governments to be able to contribute to the greatest good of society, to socially effective not- for- profit organisations. Despite the importance of a degree in Commerce there are some criticisms about the degree and Commerce graduates. The problem statement of this study is therefore vested in the continuum of praise and criticisms of Commerce graduates and the Commerce curriculum and, the reported imbalances between higher education institutions and the needs of the labour market. The question is whether such praise and criticisms are justified and whether higher education institutions specifically meet the requirements and expectations of both the graduates themselves and of business practice. The primary research objective of this study was, therefore, to obtain the opinions of Commerce graduates and Commerce graduate employers on the overall perception of Commerce graduates produced by a prominent HEI in the Eastern Cape Province in South iv Africa. To achieve this objective and based on in-depth analysis of secondary sources, two independent empirical surveys, aimed at two population strata were conducted, namely: • The Commerce graduates with known email addresses (N = 1 870) were extracted from the HEI’s alumni database. A total of 231 usable questionnaires were received from these Commerce graduates. • The employers with known addresses (N = 85) were extracted from the selected HEIs Career Centre database. A total of 47 usable questionnaires were received from the employers of the Commerce graduates. The main findings in this research pertain to aspects concerning core courses in the Commerce curriculum offered by the selected HEI, management skills and traits as required in the work environment, commerce curriculum outcomes and perceived experience as a student in the Faculty of Commerce at the selected HEI and Employer perceptions on the profile of the Commerce graduate. In this regard, the main findings are therefore summarised below: • Both graduates and employers assigned high relative importance scores to seventeen of the 19 core courses, supporting the multi-functionary interdisciplinary approach to the Commerce curriculum. Concerns were expressed by the Commerce graduates with the quality of tuition they had received in most of the core courses. Likewise, employers were not always satisfied with the Commerce graduates’ proficiency in some of the core courses, relative to the importance of core courses for running a business. • The Commerce graduates and employers strongly endorsed and supported the importance of the 43 management skills and traits in the work environment. Commerce graduates expressed concerns about the extent to which their management skills and traits had been developed through tuition. Concerns about the proficiency of the Commerce graduates in all the management skills and traits, relative to the importance in the work place, were conveyed by the employers. • On average the perceptions on the outcome of studies in the Faculty of Commerce were very highly regarded by the Commerce graduates. The highest mean score was for the item “Studying in the Faculty of Commerce contributed to an increase in my knowledge and abilities.”• The perceived experience of Commerce graduates as students in the Faculty of Commerce at the selected HEI was very highly regarded, implying that the selected HEI was meeting the expectations of its Commerce graduates. • Employer perceptions of what would constitute an ideal Commerce graduate were not fully met by the profile of the actual Commerce graduate from the selected HEI.
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Performance of defensive shares on the JSE during financial crisis: evidence from analysis of returns and volatility
- Authors: Arguile, Wayne Peter
- Date: 2012
- Subjects: Industries -- South Africa -- Finance Industries -- South Africa -- Statistics Johannesburg Stock Exchange Rational expectations (Economic theory)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1001 , http://hdl.handle.net/10962/d1002736
- Description: This study analyses whether historically defensive sectors on the JSE have – with respect to the market – proven to be defensive during the recent global financial crisis. By withstanding the shocks of market volatility, defensive industries (such as pharmaceuticals and consumer staples) are renowned for their consistent performance throughout the business cycle. Using daily data for the period 2000–2009, the study compares the descriptive statistics of sector returns before and during the crisis. The volatility of each sector relative to the market index is calculated using the CAPM beta and a simplified volatility ratio. The same comparison is extended to the conditional volatilities of each of the sectors, which is estimated using the GARCH model and two of its extensions: the EGARCH and GJR GARCH models. While no sector experienced a positive mean return during the financial crisis, Healthcare, Consumer Goods, Consumer Services and Industrials all proved less volatile than the market. Surprisingly, Telecommunications proved more volatile than the market and experienced leverage effects during the financial crisis. Since the timing of a recession is difficult to predict, defensive securities were found to be a useful investment tool for protection against adverse movements in the stock market.
- Full Text:
- Authors: Arguile, Wayne Peter
- Date: 2012
- Subjects: Industries -- South Africa -- Finance Industries -- South Africa -- Statistics Johannesburg Stock Exchange Rational expectations (Economic theory)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1001 , http://hdl.handle.net/10962/d1002736
- Description: This study analyses whether historically defensive sectors on the JSE have – with respect to the market – proven to be defensive during the recent global financial crisis. By withstanding the shocks of market volatility, defensive industries (such as pharmaceuticals and consumer staples) are renowned for their consistent performance throughout the business cycle. Using daily data for the period 2000–2009, the study compares the descriptive statistics of sector returns before and during the crisis. The volatility of each sector relative to the market index is calculated using the CAPM beta and a simplified volatility ratio. The same comparison is extended to the conditional volatilities of each of the sectors, which is estimated using the GARCH model and two of its extensions: the EGARCH and GJR GARCH models. While no sector experienced a positive mean return during the financial crisis, Healthcare, Consumer Goods, Consumer Services and Industrials all proved less volatile than the market. Surprisingly, Telecommunications proved more volatile than the market and experienced leverage effects during the financial crisis. Since the timing of a recession is difficult to predict, defensive securities were found to be a useful investment tool for protection against adverse movements in the stock market.
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Peripheral vision field fatigue during simulated driving : the effects of time on task and time of day on selected psychophysiological, performance and subjective responses
- Authors: Robertson, Jade Kelly
- Date: 2012 , 2012-09-22
- Subjects: Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5141 , http://hdl.handle.net/10962/d1007136 , Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Description: Worldwide, motor accidents are responsible for a large number of deaths and disabilities (Connor et al., 2001), and one of the major causes of motor accidents is driver fatigue. Although majority of drivers are aware of the dangers of fatigued driving, accidents related to this continues to contribute to a large percentage of all accidents, between 5 and 50% (Nilsson et al., 1997; Williamson et al., 2011). The purpose of the research was to establish the effect that fatigue renders on an individual’s peripheral visual field and to determine whether a decrement in driving performance occurs at the same rate as a decrement in peripheral visual performance. Fatigue was induced through time of day as well as time on task. Sixteen students from Rhodes University were recruited, subject to no previous sleep disorders, among other criteria. Each participant was required to partake in two conditions, namely a day condition (09h00–11h00) and a night condition (23h00– 01h00). Each condition consisted of a 90 minute dual task; the primary task was a tracking task, in which participants were instructed to track a white line as accurately as possible. A secondary peripheral response task was introduced, in which participants were instructed to respond as quickly as possible to the peripheral stimuli, by pressing one of two clickers located on the steering wheel. The peripheral stimuli were located at 20º, 30º and 40º visual angle. Psychophysiological, performance and subjective measures were obtained before, during and after the main task. The pre- and post-tests included core body temperature, critical flicker fusion frequency threshold, a digit span memory test, Wits Sleepiness Scale and a NASA-TLX questionnaire. The psychophysiological and performance measures of heart rate, heart rate variability, blink frequency, blink duration, lane deviation, number of saccades towards peripheral stimuli, response time to peripheral stimuli and the percentage of missed peripheral responses were all recorded throughout the 90 minute main dual task. The results revealed significant differences (p<0.05) for heart rate variability, number of saccades towards peripheral stimuli and the Wits Sleepiness Scale, with regard to time of day. For time on task, significant effects were established for lane deviation, response time to peripheral stimuli, percentage of missed peripheral responses, heart rate, heart rate variability, blink frequency, blink duration, critical flicker fusion frequency threshold, core body temperature and the Wits Sleepiness Scale. Eccentricity was analysed and found to be significant for response time to peripheral stimuli, as well as for the percentage of missed peripheral responses; there was a significant increase in both measures with an increase in the stimuli eccentricity. No significances were established for time of day or between the pre- and post-tests conducted for the digit span memory performance; however, a significant interactional effect between the two was established. When assessing the percentage rate of decrement of driving performance compared to the percentage rate in the decrement of the missed peripheral responses, it was found that the percentage rate of decrement was equal for both measures. Thus from this research it can be seen that, concurrent with a decrement in driving performance, there are adverse effects on an individuals' peripheral vision, which have great implications for the safety of workers in industry and transport, as well as motorists. It was also established that time on task is possibly a more appropriate variable to consider than time of day, when implementing work schedules and rest breaks in industry, transport and fields alike, as more significant findings were seen for time on task compared to time of day. , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Authors: Robertson, Jade Kelly
- Date: 2012 , 2012-09-22
- Subjects: Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5141 , http://hdl.handle.net/10962/d1007136 , Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Description: Worldwide, motor accidents are responsible for a large number of deaths and disabilities (Connor et al., 2001), and one of the major causes of motor accidents is driver fatigue. Although majority of drivers are aware of the dangers of fatigued driving, accidents related to this continues to contribute to a large percentage of all accidents, between 5 and 50% (Nilsson et al., 1997; Williamson et al., 2011). The purpose of the research was to establish the effect that fatigue renders on an individual’s peripheral visual field and to determine whether a decrement in driving performance occurs at the same rate as a decrement in peripheral visual performance. Fatigue was induced through time of day as well as time on task. Sixteen students from Rhodes University were recruited, subject to no previous sleep disorders, among other criteria. Each participant was required to partake in two conditions, namely a day condition (09h00–11h00) and a night condition (23h00– 01h00). Each condition consisted of a 90 minute dual task; the primary task was a tracking task, in which participants were instructed to track a white line as accurately as possible. A secondary peripheral response task was introduced, in which participants were instructed to respond as quickly as possible to the peripheral stimuli, by pressing one of two clickers located on the steering wheel. The peripheral stimuli were located at 20º, 30º and 40º visual angle. Psychophysiological, performance and subjective measures were obtained before, during and after the main task. The pre- and post-tests included core body temperature, critical flicker fusion frequency threshold, a digit span memory test, Wits Sleepiness Scale and a NASA-TLX questionnaire. The psychophysiological and performance measures of heart rate, heart rate variability, blink frequency, blink duration, lane deviation, number of saccades towards peripheral stimuli, response time to peripheral stimuli and the percentage of missed peripheral responses were all recorded throughout the 90 minute main dual task. The results revealed significant differences (p<0.05) for heart rate variability, number of saccades towards peripheral stimuli and the Wits Sleepiness Scale, with regard to time of day. For time on task, significant effects were established for lane deviation, response time to peripheral stimuli, percentage of missed peripheral responses, heart rate, heart rate variability, blink frequency, blink duration, critical flicker fusion frequency threshold, core body temperature and the Wits Sleepiness Scale. Eccentricity was analysed and found to be significant for response time to peripheral stimuli, as well as for the percentage of missed peripheral responses; there was a significant increase in both measures with an increase in the stimuli eccentricity. No significances were established for time of day or between the pre- and post-tests conducted for the digit span memory performance; however, a significant interactional effect between the two was established. When assessing the percentage rate of decrement of driving performance compared to the percentage rate in the decrement of the missed peripheral responses, it was found that the percentage rate of decrement was equal for both measures. Thus from this research it can be seen that, concurrent with a decrement in driving performance, there are adverse effects on an individuals' peripheral vision, which have great implications for the safety of workers in industry and transport, as well as motorists. It was also established that time on task is possibly a more appropriate variable to consider than time of day, when implementing work schedules and rest breaks in industry, transport and fields alike, as more significant findings were seen for time on task compared to time of day. , Adobe Acrobat 9.53 Paper Capture Plug-in
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Perspectives on China's rise in Namibia: the effects on foreign policy and domestic politics
- Amadhila, Nelago Ndapandula Ndanyanyukwa
- Authors: Amadhila, Nelago Ndapandula Ndanyanyukwa
- Date: 2012
- Subjects: Namibia -- Relations -- China China -- Relations -- Namibia Namibia -- Politics and government -- Chinese influences Namibia -- Economic conditions -- Chinese influences
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2758 , http://hdl.handle.net/10962/d1002968
- Description: This thesis analyses the different levels at which China’s presence in Namibia affects Namibia’s domestic politics and foreign policy from a constructivist viewpoint. Constructivist theory is used to examine the different perceptions of the Chinese in Namibia and how these inform Namibian politics and Sino-Namibian relations. These perceptions are formed at different levels of society in formal and informal relations, state-to-state, state-to-business,business-to-business and individual-to-group relations. The way in which perceptions of Chinese involvement in Namibia at the grassroots level of society differ from those at the top increasingly has an effect on domestic Namibian politics and, as such, Sino-Namibian relations. This identifies official and non-official perceptions of China’s political, economic and social presence to determine the effects of grassroots on China vis-à-vis official perceptions in Namibian politics and the effects of grassroots views on Namibian politics and on official views and state behaviour towards China and China’s presence in the country.
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- Authors: Amadhila, Nelago Ndapandula Ndanyanyukwa
- Date: 2012
- Subjects: Namibia -- Relations -- China China -- Relations -- Namibia Namibia -- Politics and government -- Chinese influences Namibia -- Economic conditions -- Chinese influences
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2758 , http://hdl.handle.net/10962/d1002968
- Description: This thesis analyses the different levels at which China’s presence in Namibia affects Namibia’s domestic politics and foreign policy from a constructivist viewpoint. Constructivist theory is used to examine the different perceptions of the Chinese in Namibia and how these inform Namibian politics and Sino-Namibian relations. These perceptions are formed at different levels of society in formal and informal relations, state-to-state, state-to-business,business-to-business and individual-to-group relations. The way in which perceptions of Chinese involvement in Namibia at the grassroots level of society differ from those at the top increasingly has an effect on domestic Namibian politics and, as such, Sino-Namibian relations. This identifies official and non-official perceptions of China’s political, economic and social presence to determine the effects of grassroots on China vis-à-vis official perceptions in Namibian politics and the effects of grassroots views on Namibian politics and on official views and state behaviour towards China and China’s presence in the country.
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PhDs by publications
- Niven, Penelope, Grant, Carolyn
- Authors: Niven, Penelope , Grant, Carolyn
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281108 , vital:55693 , xlink:href="https://doi.org/10.1080/13562517.2012.640086"
- Description: PhDs by publications are a relatively new model for doctoral research, especially in the context of the Humanities or Education. This paper describes two writers’ experiences of conducting doctoral studies in this genre and in these faculties. Each discover alternative ways of employing a body of published research papers in development of an overarching thesis. The writers argue that whilst it can be a pragmatic choice for some, PhDs by publications are more likely to be highly complex meta-narratives and that an overview of past research is fraught with theoretical, conceptual and epistemological challenges in the quest for coherence. They claim that the nomenclature ‘PhDs by publications’ or ‘through publications’ is misleading: in the epistemological space of Humanities or Education studies, this mode of doctoral research is more accurately represented as a ‘PhD with or alongside publications’. They conclude that the particular affordance of the model is that it privileges accounts of the process of knowledge building and of descriptions of the gradual emergence of ‘doctoralness’ in the person of the researcher.
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- Authors: Niven, Penelope , Grant, Carolyn
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281108 , vital:55693 , xlink:href="https://doi.org/10.1080/13562517.2012.640086"
- Description: PhDs by publications are a relatively new model for doctoral research, especially in the context of the Humanities or Education. This paper describes two writers’ experiences of conducting doctoral studies in this genre and in these faculties. Each discover alternative ways of employing a body of published research papers in development of an overarching thesis. The writers argue that whilst it can be a pragmatic choice for some, PhDs by publications are more likely to be highly complex meta-narratives and that an overview of past research is fraught with theoretical, conceptual and epistemological challenges in the quest for coherence. They claim that the nomenclature ‘PhDs by publications’ or ‘through publications’ is misleading: in the epistemological space of Humanities or Education studies, this mode of doctoral research is more accurately represented as a ‘PhD with or alongside publications’. They conclude that the particular affordance of the model is that it privileges accounts of the process of knowledge building and of descriptions of the gradual emergence of ‘doctoralness’ in the person of the researcher.
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Photooxidation of 4-chlorophenol sensitized by lutetium tetraphenoxy phthalocyanine anchored on electrospun polystyrene polymer fiber
- Zugle, Ruphino, Antunes, Edith M, Khene, Samson M, Nyokong, Tebello
- Authors: Zugle, Ruphino , Antunes, Edith M , Khene, Samson M , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245787 , vital:51405 , xlink:href="https://doi.org/10.1016/j.poly.2011.11.005"
- Description: An electrospun polystyrene (PS) fiber incorporating tetraphenoxy phthalocyanine complex of lutetium (LuTPPc/PS) as a photosensitizer was applied for the degradation of 4-chlorophenol in aqueous solution in the presence of visible light. The photocatalytic activity of the LuTPPc in the fiber was compared to that of zinc phthalocyanine (ZnPc) incorporated into the PS fiber, and the former showed higher activity. UV–Vis spectral changes of sample solutions indicated transformation of the analyte with first order kinetics and half-lives that are within one and half hours for LuTPPc/PS. Products identified from the spectral changes and gas chromatography were benzoquinone, hydroquinone and 4,4′-dihydroxydiphenol suggesting that the photodegradation of 4-chlorophenol was through both Types I and II mechanisms.
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- Authors: Zugle, Ruphino , Antunes, Edith M , Khene, Samson M , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245787 , vital:51405 , xlink:href="https://doi.org/10.1016/j.poly.2011.11.005"
- Description: An electrospun polystyrene (PS) fiber incorporating tetraphenoxy phthalocyanine complex of lutetium (LuTPPc/PS) as a photosensitizer was applied for the degradation of 4-chlorophenol in aqueous solution in the presence of visible light. The photocatalytic activity of the LuTPPc in the fiber was compared to that of zinc phthalocyanine (ZnPc) incorporated into the PS fiber, and the former showed higher activity. UV–Vis spectral changes of sample solutions indicated transformation of the analyte with first order kinetics and half-lives that are within one and half hours for LuTPPc/PS. Products identified from the spectral changes and gas chromatography were benzoquinone, hydroquinone and 4,4′-dihydroxydiphenol suggesting that the photodegradation of 4-chlorophenol was through both Types I and II mechanisms.
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Photophysical and photochemical properties of novel phthalocyanines bearing non-peripherally substituted mercaptoquinoline moiety
- Yaşa, Göknur, Erdoğmuş, Ali, Uğur, Ahmet Lütf, Şener, M Kasım, Avcıata, Ulvi, Nyokong, Tebello
- Authors: Yaşa, Göknur , Erdoğmuş, Ali , Uğur, Ahmet Lütf , Şener, M Kasım , Avcıata, Ulvi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244360 , vital:51250 , xlink:href="https://doi.org/10.1142/S1088424612500940"
- Description: The synthesis, photophysical and photochemical properties of nonperipherally (a) mercaptoquinoline substituted Zn(II), TiO(IV) and Mg(II) and quaternized Zn(II) phthalocyanines are described for the first time. These complexes (2 to 5) and their precursor are characterized by elemental analysis, FT-IR, 1 H NMR, electronic spectroscopy as well as mass spectroscopy. Complexes 2, 4 and 5 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in all solvents within a wide concentration range. Complex 3 showed very good solubility in water as well as DMSO and DMF. General trends are described for singlet oxygen, photodegradation and fluorescence quantum yields of these complexes in DMSO and DMF. While complex 2 has higher singlet oxygen and fluorescence quantum yields than 3, 4 and 5, complex 4 has higher fluorescence quantum yields in DMF and DMSO than 2, 3 and 5. The effect of the solvents and metal on the photophysical and photochemical parameters of the metallophthalocyanines are also reported.
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- Authors: Yaşa, Göknur , Erdoğmuş, Ali , Uğur, Ahmet Lütf , Şener, M Kasım , Avcıata, Ulvi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244360 , vital:51250 , xlink:href="https://doi.org/10.1142/S1088424612500940"
- Description: The synthesis, photophysical and photochemical properties of nonperipherally (a) mercaptoquinoline substituted Zn(II), TiO(IV) and Mg(II) and quaternized Zn(II) phthalocyanines are described for the first time. These complexes (2 to 5) and their precursor are characterized by elemental analysis, FT-IR, 1 H NMR, electronic spectroscopy as well as mass spectroscopy. Complexes 2, 4 and 5 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in all solvents within a wide concentration range. Complex 3 showed very good solubility in water as well as DMSO and DMF. General trends are described for singlet oxygen, photodegradation and fluorescence quantum yields of these complexes in DMSO and DMF. While complex 2 has higher singlet oxygen and fluorescence quantum yields than 3, 4 and 5, complex 4 has higher fluorescence quantum yields in DMF and DMSO than 2, 3 and 5. The effect of the solvents and metal on the photophysical and photochemical parameters of the metallophthalocyanines are also reported.
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Photophysical and photochemical studies of sulfur containing phthalocyanine derivatives in the presence of folic acid
- Nombona, Nolwazi, Nyokong, Tebello
- Authors: Nombona, Nolwazi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243180 , vital:51124 , xlink:href="https://doi.org/10.1016/j.ica.2012.03.051"
- Description: The syntheses of zinc and magnesium 9,16,23-tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyaninato complexes are described for the first time. The photophysical and photochemical parameters of these molecules in the absence or presence of folic acid are compared to the corresponding oxygen bridged complexes and to 2,9,17,23-tetrakis-[(1,6-hexanedithiol)phthalocyaninato]zinc(II), [8,15,22-tris-(naptho)-2-(amidoethanethiol)phthalocyaninato]zinc(II) and zinc phthalocyanine tetrasulfonate. In the absence of folic acid, the complexes show relatively good triplet quantum yields (ranging from 0.52 to 0.88) in DMSO with reasonable triplet lifetime between 140 and 470 μs. The complexes showed high singlet oxygen quantum yield values ranging from 0.27 to 0.66 in the absence of folic acid. In the presence of folic acid, the triplet quantum yield values were between 0.37 and 0.75 and the lifetimes were significantly reduced (70–320 μs).
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- Authors: Nombona, Nolwazi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243180 , vital:51124 , xlink:href="https://doi.org/10.1016/j.ica.2012.03.051"
- Description: The syntheses of zinc and magnesium 9,16,23-tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyaninato complexes are described for the first time. The photophysical and photochemical parameters of these molecules in the absence or presence of folic acid are compared to the corresponding oxygen bridged complexes and to 2,9,17,23-tetrakis-[(1,6-hexanedithiol)phthalocyaninato]zinc(II), [8,15,22-tris-(naptho)-2-(amidoethanethiol)phthalocyaninato]zinc(II) and zinc phthalocyanine tetrasulfonate. In the absence of folic acid, the complexes show relatively good triplet quantum yields (ranging from 0.52 to 0.88) in DMSO with reasonable triplet lifetime between 140 and 470 μs. The complexes showed high singlet oxygen quantum yield values ranging from 0.27 to 0.66 in the absence of folic acid. In the presence of folic acid, the triplet quantum yield values were between 0.37 and 0.75 and the lifetimes were significantly reduced (70–320 μs).
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Photophysicochemical and photodynamic studies of phthalocyanines conjugated to selected drug delivery agents
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
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- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
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Photophysicochemical studies of phenylthio phthalocyanines interaction with gold nanoparticles and applications in dye sensitised solar cells and optical limiting
- Authors: Forteath, Shaun
- Date: 2012
- Subjects: Phthalocyanines , Nanoparticles , Photochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4334 , http://hdl.handle.net/10962/d1004995 , Phthalocyanines , Nanoparticles , Photochemistry
- Description: The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.
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- Authors: Forteath, Shaun
- Date: 2012
- Subjects: Phthalocyanines , Nanoparticles , Photochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4334 , http://hdl.handle.net/10962/d1004995 , Phthalocyanines , Nanoparticles , Photochemistry
- Description: The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.
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Photophysics and photochemistry of octaglucosylated zinc phthalocyanine derivatives
- Iqbal, Zafar, Ogunsipe, Abimbola, Nyokong, Tebello, Lyubimtsev, Alexey, Hanack, Michael, Ziegler, Thomas
- Authors: Iqbal, Zafar , Ogunsipe, Abimbola , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244416 , vital:51255 , xlink:href="https://doi.org/10.1142/S1088424612500630"
- Description: The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.
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- Authors: Iqbal, Zafar , Ogunsipe, Abimbola , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244416 , vital:51255 , xlink:href="https://doi.org/10.1142/S1088424612500630"
- Description: The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.
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Physico-chemical properties of lutetium phthalocyanine complexes in solution and in solid polystyrene polymer fibers and their application in photoconversion of 4-nitrophenol
- Zugle, Ruphino, Nyokong, Tebello
- Authors: Zugle, Ruphino , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243520 , vital:51160 , xlink:href="https://doi.org/10.1016/j.molcata.2012.02.010"
- Description: The photophysical and photochemical behavior of two phthalocyanine complexes of lutetium peripherally substituted with tetraphenoxy and tetra-2-pyridiloxy groups were studied in solution and when dispersed in polystyrene polymer fiber. The phthalocyanines were found not to fluoresce significantly in solution and not at all within the fiber matrix as compared with standard unsubstituted zinc phthalocyanine. They showed very promising photoactivity in solution with high singlet oxygen quantum yields. Their photoactivity within the polymer fiber matrix was also demonstrated with the photoconversion of 4-nitrophenol, a water pollutant. The photodegradation process with both phthalocyanines follows first order kinetics similar to that observed for the zinc phthalocyanine and the photo-products were found to be hydroquinone, benzoquinone and 4-nitrocatechol.
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- Authors: Zugle, Ruphino , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243520 , vital:51160 , xlink:href="https://doi.org/10.1016/j.molcata.2012.02.010"
- Description: The photophysical and photochemical behavior of two phthalocyanine complexes of lutetium peripherally substituted with tetraphenoxy and tetra-2-pyridiloxy groups were studied in solution and when dispersed in polystyrene polymer fiber. The phthalocyanines were found not to fluoresce significantly in solution and not at all within the fiber matrix as compared with standard unsubstituted zinc phthalocyanine. They showed very promising photoactivity in solution with high singlet oxygen quantum yields. Their photoactivity within the polymer fiber matrix was also demonstrated with the photoconversion of 4-nitrophenol, a water pollutant. The photodegradation process with both phthalocyanines follows first order kinetics similar to that observed for the zinc phthalocyanine and the photo-products were found to be hydroquinone, benzoquinone and 4-nitrocatechol.
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Political agency in South African shack settlements
- Authors: Pithouse, Richard, 1970-
- Date: 2012
- Language: English
- Type: Conference paper
- Identifier: vital:6194 , http://hdl.handle.net/10962/d1008580
- Description: (From the introduction) In 2004 Mike Davis asked whether or not what he called 'the informal proletariat' could attain historical agency. The question posed by Davis sparked a largely speculative discussion in the radical edge of the metropolitan academy that often paid scant regard to the many careful studies dealing with the political agency of shack dwellers. The debate about the political capacities of the urban poor stretches back to Karl Marx and Friedrich Engels, whose views on the matter are well known, and Mikhail Bakunin who sustained their objectification but inverted its logic to conclude that “in them and only in them [the lumpen-proletariat ], and not in the bourgeois strata of workers, are there crystallized the entire intelligence and power of the coming Social Revolution”. In Africa the rational discussion of this question begins with Frantz Fanon who,dying of leukaemia and dictating his words from a mattress on the floor of a flat in Tunis in 1961, insisted that “Marxist analysis should always be slightly stretched every time we have to do with the colonial problem.” One of the many ways in which he stretched the Marxism in the air at the time was to take the view that the lumpen-proletariat, as a sociological category, had no fixed political meaning. People who had been 'circling the cities' hoping, he said, 'to be let in', had sometimes offered their services to colonial oppression and had sometimes joined the revolution against colonialism. Moreover he argued that in the colonial context the urban poor, living outside of the “world of compartments”, did not only become a “gangrene eating into the heart of colonial domination” as an unintended consequence of a desire to survive, of a “biological decision to invade the enemy citadels”, but that some amongst these people would assume explicit political agency and that it is: “in the people of the shanty towns and in the lumpen-proletariat that the insurrection will find its urban spearhead.” In reaching this conclusion, and in insisting on this particular stretching of the dominant currents of the Marxism of the time, Fanon was sustaining a fidelity both to the actually existing politics that he had witnessed in various African countries as well as to his founding ethical axiom - to recognise “the open door of every consciousness.”
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- Authors: Pithouse, Richard, 1970-
- Date: 2012
- Language: English
- Type: Conference paper
- Identifier: vital:6194 , http://hdl.handle.net/10962/d1008580
- Description: (From the introduction) In 2004 Mike Davis asked whether or not what he called 'the informal proletariat' could attain historical agency. The question posed by Davis sparked a largely speculative discussion in the radical edge of the metropolitan academy that often paid scant regard to the many careful studies dealing with the political agency of shack dwellers. The debate about the political capacities of the urban poor stretches back to Karl Marx and Friedrich Engels, whose views on the matter are well known, and Mikhail Bakunin who sustained their objectification but inverted its logic to conclude that “in them and only in them [the lumpen-proletariat ], and not in the bourgeois strata of workers, are there crystallized the entire intelligence and power of the coming Social Revolution”. In Africa the rational discussion of this question begins with Frantz Fanon who,dying of leukaemia and dictating his words from a mattress on the floor of a flat in Tunis in 1961, insisted that “Marxist analysis should always be slightly stretched every time we have to do with the colonial problem.” One of the many ways in which he stretched the Marxism in the air at the time was to take the view that the lumpen-proletariat, as a sociological category, had no fixed political meaning. People who had been 'circling the cities' hoping, he said, 'to be let in', had sometimes offered their services to colonial oppression and had sometimes joined the revolution against colonialism. Moreover he argued that in the colonial context the urban poor, living outside of the “world of compartments”, did not only become a “gangrene eating into the heart of colonial domination” as an unintended consequence of a desire to survive, of a “biological decision to invade the enemy citadels”, but that some amongst these people would assume explicit political agency and that it is: “in the people of the shanty towns and in the lumpen-proletariat that the insurrection will find its urban spearhead.” In reaching this conclusion, and in insisting on this particular stretching of the dominant currents of the Marxism of the time, Fanon was sustaining a fidelity both to the actually existing politics that he had witnessed in various African countries as well as to his founding ethical axiom - to recognise “the open door of every consciousness.”
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Post-apartheid racial integration in Grahamstown : a time-geographical perspective
- Authors: Irvine, Philippa Margaret
- Date: 2012
- Subjects: Race discrimination -- South Africa -- Eastern Cape Grahamstown (South Africa) -- Race relations Grahamstown (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4845 , http://hdl.handle.net/10962/d1005521
- Description: This research is situated within the context of the post-apartheid era in South Africa, which includes the dominant ideologies and policies that have shaped the urban landscape of the past and present. It investigates the extent and patterns of integration that exist twenty years after the country’s political transition and it uses Grahamstown, a small education and cultural centre in the Eastern Cape Province, as its case study. The investigation incorporates the traditional geographical focus of residential and educational integration, using conventional means of investigation such as segregation indices, dissimilarity indices, percentages and maps. However, in identifying the broader nature of ‘segregation’ and ‘integration’, the study moves beyond these foci and approaches. It adopts the timegeographical framework to reveal the dynamic use of urban space that reflects the lived space of selected individuals from the community of Grahamstown: the extent and patterns of their behavioural integration or spatial linkages. Together, these approaches reveal that Grahamstown is still a city divided by race and, now, class. Schools and residential areas remain tied to the apartheid divisions of race and the white community exists almost entirely within the bounds of apartheid’s blueprint of urban space. Rhodes University, which is located within Grahamstown, has experienced admirable levels of integration within the student body and within the staff as a whole, but not within the staff’s different levels. In essence, where integration has occurred it has been unidirectional with the black community moving into the spaces and institutions formerly reserved for whites. The limited behavioural integration or spatial linkages are shown to be tied to city structure and, within the white group, to perceptions of ‘otherness’ held by the individuals interviewed. While the study shows limited differences in the time-spatial movements between members of different races who are resident in the former white group area, it highlights the differences between those more permanently resident in the city and the temporary educational migrants or students. The study argues that the slow pace of change is related to the nature of South Africa’s democratic transition and its attending political and economic policies.
- Full Text:
- Authors: Irvine, Philippa Margaret
- Date: 2012
- Subjects: Race discrimination -- South Africa -- Eastern Cape Grahamstown (South Africa) -- Race relations Grahamstown (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4845 , http://hdl.handle.net/10962/d1005521
- Description: This research is situated within the context of the post-apartheid era in South Africa, which includes the dominant ideologies and policies that have shaped the urban landscape of the past and present. It investigates the extent and patterns of integration that exist twenty years after the country’s political transition and it uses Grahamstown, a small education and cultural centre in the Eastern Cape Province, as its case study. The investigation incorporates the traditional geographical focus of residential and educational integration, using conventional means of investigation such as segregation indices, dissimilarity indices, percentages and maps. However, in identifying the broader nature of ‘segregation’ and ‘integration’, the study moves beyond these foci and approaches. It adopts the timegeographical framework to reveal the dynamic use of urban space that reflects the lived space of selected individuals from the community of Grahamstown: the extent and patterns of their behavioural integration or spatial linkages. Together, these approaches reveal that Grahamstown is still a city divided by race and, now, class. Schools and residential areas remain tied to the apartheid divisions of race and the white community exists almost entirely within the bounds of apartheid’s blueprint of urban space. Rhodes University, which is located within Grahamstown, has experienced admirable levels of integration within the student body and within the staff as a whole, but not within the staff’s different levels. In essence, where integration has occurred it has been unidirectional with the black community moving into the spaces and institutions formerly reserved for whites. The limited behavioural integration or spatial linkages are shown to be tied to city structure and, within the white group, to perceptions of ‘otherness’ held by the individuals interviewed. While the study shows limited differences in the time-spatial movements between members of different races who are resident in the former white group area, it highlights the differences between those more permanently resident in the city and the temporary educational migrants or students. The study argues that the slow pace of change is related to the nature of South Africa’s democratic transition and its attending political and economic policies.
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Pre-concentration of heavy metals in aqueous environments using electrospun polymer nanofiber sorbents
- Authors: Darko, Godfred
- Date: 2012
- Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
- Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
- Full Text:
- Authors: Darko, Godfred
- Date: 2012
- Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
- Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
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