A 150 MHz all sky survey with the Precision Array to Probe the Epoch of Reionization
- Authors: Chege, James Kariuki
- Date: 2020
- Subjects: Epoch of reionization -- Research , Astronomy -- Observations , Radio interferometers
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/117733 , vital:34556
- Description: The Precision Array to Probe the Epoch of Reionization (PAPER) was built to measure the redshifted 21 cm line of hydrogen from cosmic reionization. Such low frequency observations promise to be the best means of understanding the cosmic dawn; when the first galaxies in the universe formed, and also the Epoch of Reionization; when the intergalactic medium changed from neutral to ionized. The major challenges to these observations is the presence of astrophysical foregrounds that are much brighter than the cosmological signal. Here, I present an all-sky survey at 150 MHz obtained from the analysis of 300 hours of PAPER observations. Particular focus is given to the calibration and imaging techniques that need to deal with the wide field of view of a non-tracking instrument. The survey covers ~ 7000 square degrees of the southern sky. From a sky area of 4400 square degrees out of the total survey area, I extract a catalogue of sources brighter than 4 Jy whose accuracy was tested against the published GLEAM catalogue, leading to a fractional difference rms better than 20%. The catalogue provides an all-sky accurate model of the extragalactic foreground to be used for the calibration of future Epoch of Reionization observations and to be subtracted from the PAPER observations themselves in order to mitigate the foreground contamination.
- Full Text:
- Date Issued: 2020
- Authors: Chege, James Kariuki
- Date: 2020
- Subjects: Epoch of reionization -- Research , Astronomy -- Observations , Radio interferometers
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/117733 , vital:34556
- Description: The Precision Array to Probe the Epoch of Reionization (PAPER) was built to measure the redshifted 21 cm line of hydrogen from cosmic reionization. Such low frequency observations promise to be the best means of understanding the cosmic dawn; when the first galaxies in the universe formed, and also the Epoch of Reionization; when the intergalactic medium changed from neutral to ionized. The major challenges to these observations is the presence of astrophysical foregrounds that are much brighter than the cosmological signal. Here, I present an all-sky survey at 150 MHz obtained from the analysis of 300 hours of PAPER observations. Particular focus is given to the calibration and imaging techniques that need to deal with the wide field of view of a non-tracking instrument. The survey covers ~ 7000 square degrees of the southern sky. From a sky area of 4400 square degrees out of the total survey area, I extract a catalogue of sources brighter than 4 Jy whose accuracy was tested against the published GLEAM catalogue, leading to a fractional difference rms better than 20%. The catalogue provides an all-sky accurate model of the extragalactic foreground to be used for the calibration of future Epoch of Reionization observations and to be subtracted from the PAPER observations themselves in order to mitigate the foreground contamination.
- Full Text:
- Date Issued: 2020
A sociological analysis of the involvement of men in campaigns against sexual violence towards women at Rhodes University: the aftermath of the #RUReference protest
- Authors: Roboji, Philasande Milisa
- Date: 2020
- Subjects: #RUReferenceList , Rhodes University -- Students -- Attitudes , Rape in universities and colleges -- South Africa , Social movements -- South Africa -- Makhanda , Women college students -- Violence against -- South Africa , Male college students -- South Africa -- Attitudes
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/148059 , vital:38706
- Description: Gender-based violence more especially sexual violence towards women is one of the biggest social issus affecting South Africa including higher institutions of learning, universities in this context. In recent years, we have seen students in universities protesting sexual violence demanding universities to improve their ways of dealing with this violence. The motivation behind this thesis is the notion that sexual violence is a women’s issue and how most men in our communities and universities do not involve themselves in campaigns that are designed to end sexual violence towards women. There is an assumption that women should be the ones fighting against sexual violence because it affects them when in fact sexual violence affects everyone and more importantly, is mostly perpetuated by men. Therefore, the main purpose of this thesis was to sociologically analyze the involvement of men in campaigns against sexual violence towards women and the aftermath of the #RUReferenceList protest that took place at Rhodes University in 2016. This protest started immediately after a list of students who were said to be alleged sexual perpetrators was published online. Attached to this primary objective, the sub-goals that informed the entire study were to investigate how the involvement of men in the #RUReferenceList protest has contributed to challenging rape culture at Rhodes University. Also, to investigate if there are any ongoing campaigns and/or projects that includes men and that are still addressing the issue of sexual violence towards women. There is however, a dearth of research on the involvement of men in campaigns against sexual violence in South Africa. Therefore, it was difficult finding existing literature that touches on the involvement of men in campaigns against sexual violence towards women particularly in the context of universities. This thesis was conducted within the premises of Rhodes University through a qualitative research approach in a form of in-depth interviews. Five participants were selected through purposive sampling which included the Chair of the Gender Action Forum, one former student representative council member, a sub-warden from a male residence and two students. The findings of this research are not the full representation of the entire university but opinions and perspective of the participants that were interviewed. Their opinions and perspectives have a potential of contributing to the factors and reasons as to why majority of men have not engaged themselves in issues of gender-based violence or involved themselves in campaigns against sexual violence towards women.
- Full Text:
- Date Issued: 2020
- Authors: Roboji, Philasande Milisa
- Date: 2020
- Subjects: #RUReferenceList , Rhodes University -- Students -- Attitudes , Rape in universities and colleges -- South Africa , Social movements -- South Africa -- Makhanda , Women college students -- Violence against -- South Africa , Male college students -- South Africa -- Attitudes
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/148059 , vital:38706
- Description: Gender-based violence more especially sexual violence towards women is one of the biggest social issus affecting South Africa including higher institutions of learning, universities in this context. In recent years, we have seen students in universities protesting sexual violence demanding universities to improve their ways of dealing with this violence. The motivation behind this thesis is the notion that sexual violence is a women’s issue and how most men in our communities and universities do not involve themselves in campaigns that are designed to end sexual violence towards women. There is an assumption that women should be the ones fighting against sexual violence because it affects them when in fact sexual violence affects everyone and more importantly, is mostly perpetuated by men. Therefore, the main purpose of this thesis was to sociologically analyze the involvement of men in campaigns against sexual violence towards women and the aftermath of the #RUReferenceList protest that took place at Rhodes University in 2016. This protest started immediately after a list of students who were said to be alleged sexual perpetrators was published online. Attached to this primary objective, the sub-goals that informed the entire study were to investigate how the involvement of men in the #RUReferenceList protest has contributed to challenging rape culture at Rhodes University. Also, to investigate if there are any ongoing campaigns and/or projects that includes men and that are still addressing the issue of sexual violence towards women. There is however, a dearth of research on the involvement of men in campaigns against sexual violence in South Africa. Therefore, it was difficult finding existing literature that touches on the involvement of men in campaigns against sexual violence towards women particularly in the context of universities. This thesis was conducted within the premises of Rhodes University through a qualitative research approach in a form of in-depth interviews. Five participants were selected through purposive sampling which included the Chair of the Gender Action Forum, one former student representative council member, a sub-warden from a male residence and two students. The findings of this research are not the full representation of the entire university but opinions and perspective of the participants that were interviewed. Their opinions and perspectives have a potential of contributing to the factors and reasons as to why majority of men have not engaged themselves in issues of gender-based violence or involved themselves in campaigns against sexual violence towards women.
- Full Text:
- Date Issued: 2020
Developing an organisational culture in support of organisational capacity for change: the case of a South African bank
- Authors: Dhoba, Howard
- Date: 2020
- Subjects: Corporate culture , Bank management , Organizational change
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/141247 , vital:37956
- Description: Business organisations are increasingly being exposed to challenging environmental pressures. It has been widely acknowledged and observed that an organisation that crafts an effective organisational culture should be well positioned to react to these threatening changes, and to proactively seize opportunities to adapt and learn. This research study seeks to investigate how an organisational culture that supports organisational capacity for change can be developed. It analyses what a banking organisation’s espoused culture is made up of and how it was formulated. A thematic analysis of how the bank’s aspirational and innovative culture contributes to the organisation’s capacity for change is also presented. Organisational management should take a leading role in developing the values and practices that foster participation, which are then imparted to the entire organisation. The research study thus only focused on analysing the development of organisational culture from the management perspective. An interpretivist research approach was adopted, with a case study design as the research method. Data was gathered through conducting personal interviews with twelve managers from a Retail and Business Banking cluster of one of the big South African banks. Numerous interventions were employed in the organisation to develop espoused values, aspirational culture and to encourage all employees to champion innovations and constantly search for better ways to offer delighting value propositions to clients. The research findings can assist managers and organisational leaders in building their organisational capacity for change through developing an effective organisational culture that supports change initiatives. Since the research study only focused on analysing the development of organisational culture from the perspective of management, further research studies may involve employees as well, due to the fact that everyone is expected to take an active role for an organisation to display the overall capability to effectively respond to a progressively volatile environment. The research was able to reveal how key initiatives that are designed from theoretical constructs can be used to deliver on an innovative organisational culture that contributes to organisational capability for change.
- Full Text:
- Date Issued: 2020
- Authors: Dhoba, Howard
- Date: 2020
- Subjects: Corporate culture , Bank management , Organizational change
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/141247 , vital:37956
- Description: Business organisations are increasingly being exposed to challenging environmental pressures. It has been widely acknowledged and observed that an organisation that crafts an effective organisational culture should be well positioned to react to these threatening changes, and to proactively seize opportunities to adapt and learn. This research study seeks to investigate how an organisational culture that supports organisational capacity for change can be developed. It analyses what a banking organisation’s espoused culture is made up of and how it was formulated. A thematic analysis of how the bank’s aspirational and innovative culture contributes to the organisation’s capacity for change is also presented. Organisational management should take a leading role in developing the values and practices that foster participation, which are then imparted to the entire organisation. The research study thus only focused on analysing the development of organisational culture from the management perspective. An interpretivist research approach was adopted, with a case study design as the research method. Data was gathered through conducting personal interviews with twelve managers from a Retail and Business Banking cluster of one of the big South African banks. Numerous interventions were employed in the organisation to develop espoused values, aspirational culture and to encourage all employees to champion innovations and constantly search for better ways to offer delighting value propositions to clients. The research findings can assist managers and organisational leaders in building their organisational capacity for change through developing an effective organisational culture that supports change initiatives. Since the research study only focused on analysing the development of organisational culture from the perspective of management, further research studies may involve employees as well, due to the fact that everyone is expected to take an active role for an organisation to display the overall capability to effectively respond to a progressively volatile environment. The research was able to reveal how key initiatives that are designed from theoretical constructs can be used to deliver on an innovative organisational culture that contributes to organisational capability for change.
- Full Text:
- Date Issued: 2020
Institutional culture and internationalisation: a study of Black African academics’ experiences at Rhodes University
- Authors: Wambua, Lloyd M
- Date: 2020
- Subjects: Corporate culture -- South Africa -- Makhanda , Universities and colleges -- South Africa -- Makhanda -- Sociological aspects , Discrimination in higher education -- South Africa -- Makhanda , Rhodes University , College teachers, Black -- South Africa -- Makhanda -- Social conditions , College teachers, Foreign -- South Africa -- Makhanda -- Social conditions , Globalization -- South Africa -- Makhanda , Educational change -- South Africa -- Makhanda , Sex discrimination in higher education -- South Africa -- Makhanda , South Africa -- Race relations , Intersectionality (Sociology) , Pan-Africanism , Belonging (Social psychology) , Alienation (Social psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/146607 , vital:38541
- Description: This research sets out to examine institutional culture and internationalisation in higher education in contemporary South Africa, by analysing the experiences of black foreign academics at Rhodes University. Much has been written on the adaptation processes of foreign students in South African universities (Ayliff and Wang, 2006; Dzansi and Monnapula-Mapesela, 2012; Mudhovozi, 2011). There is also a host of literature on the black South African experience of adaptation and (non) belonging at historically white universities (HWU) (Akoojee and Nkomo, 2007; Cornell and Kessi, 2017; Soudien, 2008). Comparatively less is written on whether there are any unique pressures regarding institutional culture that black foreign African academics face at historically white institutions such as Rhodes University. The black experience may be misrepresented as a homogenous one by much of the literature on higher education transformation (Batsai, 2019). But there are a host of factors that could change your experience of being ‘black’, such as your class, and gender and quite recently there has been a push to further examine the effect that one’s nationality has on their experience of being ‘black’ in the academy (Batsai, 2019). Institutional culture refers to the “behaviours and values that make up the unique psychological and social environment of a certain institution” (Toma et al., 2005). Internationalisation of higher education in the context of Africa, particularly South Africa refers to “the intentional or unintentional process to integrate intercultural, international and global dimensions in higher education” (Draft Policy Framework for the Internationalisation of Higher Education in South Africa, 2017). In analysing the experiences of international African academics, this research is trying to give a voice to an often-overlooked group of individuals. This research is also meant to portray the black experience in South African higher education as an experience that is not homogenous but reliant on a host of unique identity factors such as gender, class and also their nationality.
- Full Text:
- Date Issued: 2020
- Authors: Wambua, Lloyd M
- Date: 2020
- Subjects: Corporate culture -- South Africa -- Makhanda , Universities and colleges -- South Africa -- Makhanda -- Sociological aspects , Discrimination in higher education -- South Africa -- Makhanda , Rhodes University , College teachers, Black -- South Africa -- Makhanda -- Social conditions , College teachers, Foreign -- South Africa -- Makhanda -- Social conditions , Globalization -- South Africa -- Makhanda , Educational change -- South Africa -- Makhanda , Sex discrimination in higher education -- South Africa -- Makhanda , South Africa -- Race relations , Intersectionality (Sociology) , Pan-Africanism , Belonging (Social psychology) , Alienation (Social psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/146607 , vital:38541
- Description: This research sets out to examine institutional culture and internationalisation in higher education in contemporary South Africa, by analysing the experiences of black foreign academics at Rhodes University. Much has been written on the adaptation processes of foreign students in South African universities (Ayliff and Wang, 2006; Dzansi and Monnapula-Mapesela, 2012; Mudhovozi, 2011). There is also a host of literature on the black South African experience of adaptation and (non) belonging at historically white universities (HWU) (Akoojee and Nkomo, 2007; Cornell and Kessi, 2017; Soudien, 2008). Comparatively less is written on whether there are any unique pressures regarding institutional culture that black foreign African academics face at historically white institutions such as Rhodes University. The black experience may be misrepresented as a homogenous one by much of the literature on higher education transformation (Batsai, 2019). But there are a host of factors that could change your experience of being ‘black’, such as your class, and gender and quite recently there has been a push to further examine the effect that one’s nationality has on their experience of being ‘black’ in the academy (Batsai, 2019). Institutional culture refers to the “behaviours and values that make up the unique psychological and social environment of a certain institution” (Toma et al., 2005). Internationalisation of higher education in the context of Africa, particularly South Africa refers to “the intentional or unintentional process to integrate intercultural, international and global dimensions in higher education” (Draft Policy Framework for the Internationalisation of Higher Education in South Africa, 2017). In analysing the experiences of international African academics, this research is trying to give a voice to an often-overlooked group of individuals. This research is also meant to portray the black experience in South African higher education as an experience that is not homogenous but reliant on a host of unique identity factors such as gender, class and also their nationality.
- Full Text:
- Date Issued: 2020
The metabolic physiology of early stage Argyrosomus japonicus with insight into the potential effects of pCO2 induced ocean acidification
- Authors: Edworthy, Carla
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Larvae -- Ecology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/51417 , vital:26094
- Description: Ocean acidification is a phenomenon associated with global change and anthropogenic CO2 emissions that is changing the chemistry of seawater. These changes result in elevated pCO2 and reduced pH in seawater and this is impacting marine organisms in various ways. Marine fishes are considered generally tolerant to conditions of ocean acidification; however, these assumptions are based on juvenile and adult fish tolerance and the larval stages have not been frequently assessed. Furthermore, it has been suggested that temperate species, particularly those with an estuarine association, may be tolerant to variable CO2 and pH. This study used an eco-physiological approach to understand how the early life stages of Argyrosomus japonicus, an estuarine dependent marine fisheries species found in warm-temperate regions, may be impacted by ocean acidification. The metabolic response of early stage larvae (hatching to early juvenile stage) was assessed under conditions of elevated pCO2 and reduced pH in a controlled laboratory setting. Small volume static respirometry was used to determine the oxygen consumption rate of larvae raised in three pCO2 treatments including a low (pCO2 = 327.50 ± 80.07 µatm at pH 8.15), moderate (pCO2 477.40 ± 59.46 µatm at pH 8.03) and high treatment (PCO2 910.20 ± 136.45 µatm at pH 7.78). These treatment levels were relevant to the present (low) and projected conditions of ocean acidification for the years 2050 (moderate) and 2100 (high). Prior to experimentation with ocean acidification treatments, baseline metabolic rates and diurnal variation in oxygen consumption rates in early stage A. japonicus was determined. Distinct ontogenetic structuring of metabolic rates was observed in early stage A. japonicus, with no cyclical fluctuations in metabolic rate occurring during the 24 hour photoperiodic cycle. Pre-flexion larvae showed no metabolic response to ocean acidification treatments; however post-flexion stage larvae showed metabolic depression of standard metabolic rate in the moderate (32.5%) and high (9.5%) pCO2 treatments (P = 0.02). Larvae raised in the high pCO2 treatment also showed high levels of mortality with no individuals surviving past the post-flexion stage. Larvae raised in the moderate pCO2 treatment were unaffected. This study concluded that ocean acidification conditions expected for the end of the century will have significant impacts on the metabolism of early stage A. japonicus, which may result in reduced growth, retardation of skeletal development and ultimately survival as a result of increased mortality. Furthermore, the timing of reduced metabolic scope will significantly impact the recruitment ability of A. japonicus larvae into estuarine habitats. This could ultimately impact the sustainability of A. japonicus populations. Most importantly, this study highlighted the need to consider the combined effect of ontogeny and life-history strategy when assessing the vulnerability of species to ocean acidification.
- Full Text:
- Date Issued: 2018
- Authors: Edworthy, Carla
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Larvae -- Ecology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/51417 , vital:26094
- Description: Ocean acidification is a phenomenon associated with global change and anthropogenic CO2 emissions that is changing the chemistry of seawater. These changes result in elevated pCO2 and reduced pH in seawater and this is impacting marine organisms in various ways. Marine fishes are considered generally tolerant to conditions of ocean acidification; however, these assumptions are based on juvenile and adult fish tolerance and the larval stages have not been frequently assessed. Furthermore, it has been suggested that temperate species, particularly those with an estuarine association, may be tolerant to variable CO2 and pH. This study used an eco-physiological approach to understand how the early life stages of Argyrosomus japonicus, an estuarine dependent marine fisheries species found in warm-temperate regions, may be impacted by ocean acidification. The metabolic response of early stage larvae (hatching to early juvenile stage) was assessed under conditions of elevated pCO2 and reduced pH in a controlled laboratory setting. Small volume static respirometry was used to determine the oxygen consumption rate of larvae raised in three pCO2 treatments including a low (pCO2 = 327.50 ± 80.07 µatm at pH 8.15), moderate (pCO2 477.40 ± 59.46 µatm at pH 8.03) and high treatment (PCO2 910.20 ± 136.45 µatm at pH 7.78). These treatment levels were relevant to the present (low) and projected conditions of ocean acidification for the years 2050 (moderate) and 2100 (high). Prior to experimentation with ocean acidification treatments, baseline metabolic rates and diurnal variation in oxygen consumption rates in early stage A. japonicus was determined. Distinct ontogenetic structuring of metabolic rates was observed in early stage A. japonicus, with no cyclical fluctuations in metabolic rate occurring during the 24 hour photoperiodic cycle. Pre-flexion larvae showed no metabolic response to ocean acidification treatments; however post-flexion stage larvae showed metabolic depression of standard metabolic rate in the moderate (32.5%) and high (9.5%) pCO2 treatments (P = 0.02). Larvae raised in the high pCO2 treatment also showed high levels of mortality with no individuals surviving past the post-flexion stage. Larvae raised in the moderate pCO2 treatment were unaffected. This study concluded that ocean acidification conditions expected for the end of the century will have significant impacts on the metabolism of early stage A. japonicus, which may result in reduced growth, retardation of skeletal development and ultimately survival as a result of increased mortality. Furthermore, the timing of reduced metabolic scope will significantly impact the recruitment ability of A. japonicus larvae into estuarine habitats. This could ultimately impact the sustainability of A. japonicus populations. Most importantly, this study highlighted the need to consider the combined effect of ontogeny and life-history strategy when assessing the vulnerability of species to ocean acidification.
- Full Text:
- Date Issued: 2018
Studies in the thiophenol mediated substitution and reductive dehalogenation of 3 bromoacetylcoumarins
- Authors: Magwenzi, Faith N
- Date: 2017
- Subjects: 3-bromoacetylcoumarins , Coumarins , Halogens -- Decontamination , Thiols , Plasmodium falciparum , Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/45769 , vital:25546
- Description: A previous study conducted by our group identified indolyl-3-ethanone-a-thioethers (2.1a and 2.1b) as non-toxic, nanomolar, in vitro inhibitors of Plasmodium falciparum. Since the coumarin scaffold is associated with numerous biologically active compounds including antiprotozoal, anti-viral, anti-bacterial, and anti-inflammatory agents we were prompted to investigate coumaryl-3-ethanone-a-thioethers (2.1c) inspired by the activity of 2.1a and 2.1b against P. falciparum. We proposed a three-step synthesis of our target compounds 2.1c. The first step involved the Knoevenagel synthesis of 3-acetyl coumarins (2.3.1a - e) followed by a selective a-bromination to yield 3-bromoacetyl coumarin (2.2a). The final proposed step involved the nucleophilic displacement of the bromine by appropriately substituted thiophenols in either the presence or absence of base (K2CO3). Our initial findings revealed an unexpected major reductive dehalogenation of 2.2a into 2.3.1a. Further investigation revealed a close relationship between the electron withdrawing or donating nature of the thiophenol substituents and the relative formation of nucleophilic substitution or reductive dehalogenation products. Desired thioether products were obtained in higher yields when thiophenol was substituted with electron donating groups i.e. more nucleophilic thiophenols, while conversely, electron withdrawing substituents (i.e. lowered nucleophilicity) resulted in an increase of reductive dehalogenation. Furthermore, these results were consistent when experiments were conducted using either 2 or 1.2 equivalents of thiophenols which was an important observation in the context of two previous studies, by Oki et. al. and Israel et. al. Oki proposed that dehalogenation of a-chloro carbonyls occurs via sequential nucleophilic displacement of a-thioethers, while the study of Israel concluded that the dehalogenation of a-iodo carbonyls occurred in a single discreet step. Finally, in an effort to enhance nucleophilic substitution through the addition of K2CO3, we observed a Robinson annulation resulting in previously undescribed C-8 thiophenol functionalised dibenzo[b,d]pyran-6-ones (3.4a - e). In the introduction to this thesis, we briefly summarise the utility of coumarins in medicinal chemistry and related fields. Chapter two describes the rationalisation of our original research question and a retrosynthetic analysis of our desired compounds, followed by an initial description of the unexpected reductive dehalogenation. Chapter 3, begins with a brief review of reductive dehalogenation of a-halocarbonyls, and is followed by an analysis and discussion of our results in the context of the studies by Israel et. al. and Oki et. al.
- Full Text:
- Date Issued: 2017
- Authors: Magwenzi, Faith N
- Date: 2017
- Subjects: 3-bromoacetylcoumarins , Coumarins , Halogens -- Decontamination , Thiols , Plasmodium falciparum , Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/45769 , vital:25546
- Description: A previous study conducted by our group identified indolyl-3-ethanone-a-thioethers (2.1a and 2.1b) as non-toxic, nanomolar, in vitro inhibitors of Plasmodium falciparum. Since the coumarin scaffold is associated with numerous biologically active compounds including antiprotozoal, anti-viral, anti-bacterial, and anti-inflammatory agents we were prompted to investigate coumaryl-3-ethanone-a-thioethers (2.1c) inspired by the activity of 2.1a and 2.1b against P. falciparum. We proposed a three-step synthesis of our target compounds 2.1c. The first step involved the Knoevenagel synthesis of 3-acetyl coumarins (2.3.1a - e) followed by a selective a-bromination to yield 3-bromoacetyl coumarin (2.2a). The final proposed step involved the nucleophilic displacement of the bromine by appropriately substituted thiophenols in either the presence or absence of base (K2CO3). Our initial findings revealed an unexpected major reductive dehalogenation of 2.2a into 2.3.1a. Further investigation revealed a close relationship between the electron withdrawing or donating nature of the thiophenol substituents and the relative formation of nucleophilic substitution or reductive dehalogenation products. Desired thioether products were obtained in higher yields when thiophenol was substituted with electron donating groups i.e. more nucleophilic thiophenols, while conversely, electron withdrawing substituents (i.e. lowered nucleophilicity) resulted in an increase of reductive dehalogenation. Furthermore, these results were consistent when experiments were conducted using either 2 or 1.2 equivalents of thiophenols which was an important observation in the context of two previous studies, by Oki et. al. and Israel et. al. Oki proposed that dehalogenation of a-chloro carbonyls occurs via sequential nucleophilic displacement of a-thioethers, while the study of Israel concluded that the dehalogenation of a-iodo carbonyls occurred in a single discreet step. Finally, in an effort to enhance nucleophilic substitution through the addition of K2CO3, we observed a Robinson annulation resulting in previously undescribed C-8 thiophenol functionalised dibenzo[b,d]pyran-6-ones (3.4a - e). In the introduction to this thesis, we briefly summarise the utility of coumarins in medicinal chemistry and related fields. Chapter two describes the rationalisation of our original research question and a retrosynthetic analysis of our desired compounds, followed by an initial description of the unexpected reductive dehalogenation. Chapter 3, begins with a brief review of reductive dehalogenation of a-halocarbonyls, and is followed by an analysis and discussion of our results in the context of the studies by Israel et. al. and Oki et. al.
- Full Text:
- Date Issued: 2017
A comparative study of employment discrimination in South Africa and Canada
- Authors: Dlamini, David Vusi
- Date: 2004
- Subjects: Discrimination in employment -- Law and Legislation -- South Africa , Discrimination in employment -- Law and legislation -- Canada
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11039 , http://hdl.handle.net/10948/330 , Discrimination in employment -- Law and Legislation -- South Africa , Discrimination in employment -- Law and legislation -- Canada
- Description: South Africa and Canada have emerged from a history fraught of inequalities, which were characterised by segregationist practices. Such inequalities have served as an epitome of discrimination taking place in the society and the workplace in both countries. Both South Africa and Canada had their discrimination affecting black peoples (Africans, Indians and Coloureds) and Aboriginal peoples (Indians, Inuits or Métis) respectively, women and people with disabilities. In both countries discrimination has polarised society. It is against this backdrop that both countries have attempted to eliminate unfair discrimination through the promulgation of relevant legislation that seeks to, inter alia, provide the regulatory framework in respect of employment discrimination. With the foregoing in mind, the purpose of this work is the provision of a selection of comparable aspects of employment discrimination in Canada and South Africa. This selection comprises discrimination on the basis of race, gender, sex, pregnancy, age and HIV/AIDS. The study uses, as its departure point, both countries’ constitutional framework to elicit the extent to which protection against unfair discrimination is extended to the workforce. Apart from looking at the constitutional provisions towards the elimination of unfair discrimination, reference is made to specific employment statutory provisions in order to provide a comprehensive and explicit picture of how workplace discrimination in both countries is regulated. The study focuses on substantive law from both countries about the above -mentioned aspects of discrimination. This is informed by the very nature and scope of the study because any concentration on procedural and evidentiary aspects of discrimination could lead to failure to achieve the objectives of the study. It also looks at specific Canadian and South African case law, judgments of the courts and jurisprudence in the field of employment discrimination in order that the reader is presented with a clearer picture of recent developments in addressing workplace inequalities.
- Full Text:
- Date Issued: 2004
- Authors: Dlamini, David Vusi
- Date: 2004
- Subjects: Discrimination in employment -- Law and Legislation -- South Africa , Discrimination in employment -- Law and legislation -- Canada
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11039 , http://hdl.handle.net/10948/330 , Discrimination in employment -- Law and Legislation -- South Africa , Discrimination in employment -- Law and legislation -- Canada
- Description: South Africa and Canada have emerged from a history fraught of inequalities, which were characterised by segregationist practices. Such inequalities have served as an epitome of discrimination taking place in the society and the workplace in both countries. Both South Africa and Canada had their discrimination affecting black peoples (Africans, Indians and Coloureds) and Aboriginal peoples (Indians, Inuits or Métis) respectively, women and people with disabilities. In both countries discrimination has polarised society. It is against this backdrop that both countries have attempted to eliminate unfair discrimination through the promulgation of relevant legislation that seeks to, inter alia, provide the regulatory framework in respect of employment discrimination. With the foregoing in mind, the purpose of this work is the provision of a selection of comparable aspects of employment discrimination in Canada and South Africa. This selection comprises discrimination on the basis of race, gender, sex, pregnancy, age and HIV/AIDS. The study uses, as its departure point, both countries’ constitutional framework to elicit the extent to which protection against unfair discrimination is extended to the workforce. Apart from looking at the constitutional provisions towards the elimination of unfair discrimination, reference is made to specific employment statutory provisions in order to provide a comprehensive and explicit picture of how workplace discrimination in both countries is regulated. The study focuses on substantive law from both countries about the above -mentioned aspects of discrimination. This is informed by the very nature and scope of the study because any concentration on procedural and evidentiary aspects of discrimination could lead to failure to achieve the objectives of the study. It also looks at specific Canadian and South African case law, judgments of the courts and jurisprudence in the field of employment discrimination in order that the reader is presented with a clearer picture of recent developments in addressing workplace inequalities.
- Full Text:
- Date Issued: 2004
SACCAWU national organising and bargaining conference 19-21 March 1993: Catholic Renewal Centre Kensington, Johannesburg
- South African Commercial, Catering, and Allied Workers Union
- Authors: South African Commercial, Catering, and Allied Workers Union
- Date: 1993-03-19/21
- Subjects: Uncatalogued
- Language: eng
- Type: text , pamphlet
- Identifier: http://hdl.handle.net/10962/103509 , vital:32253
- Description: The problems surrounding SACCAWU'S wages are numerous. On analysis, large disparities are revealed. A clear guide-line in the form of a wage policy is needed. This report contains the findings of research into the problems with wages in the hotel and retail sectors of the economy. All wages used in this report are drawn from AWARD, the Labour Research Service's Actual Wage Rates Database.
- Full Text:
- Date Issued: 1993-03-19/21
- Authors: South African Commercial, Catering, and Allied Workers Union
- Date: 1993-03-19/21
- Subjects: Uncatalogued
- Language: eng
- Type: text , pamphlet
- Identifier: http://hdl.handle.net/10962/103509 , vital:32253
- Description: The problems surrounding SACCAWU'S wages are numerous. On analysis, large disparities are revealed. A clear guide-line in the form of a wage policy is needed. This report contains the findings of research into the problems with wages in the hotel and retail sectors of the economy. All wages used in this report are drawn from AWARD, the Labour Research Service's Actual Wage Rates Database.
- Full Text:
- Date Issued: 1993-03-19/21
Directory of welfare, religious and service organisations, social and sporting clubs and other societies and councils in Grahamstown
- Authors: Henderson, Thelma M
- Date: 1980
- Subjects: Associations, institutions, etc. -- South Africa -- Grahamstown -- Directories Social service -- South Africa -- Grahamstown -- Directories Church buildings -- South Africa -- Grahamstown Community education -- South Africa -- Eastern Cape Sports -- South Africa -- South Africa -- Grahamstown Social service -- South Africa -- Grahamstown Charities -- South Africa -- Grahamstown Societies -- South Africa -- Grahamstown Grahamstown -- South Africa -- Social conditions
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/2790 , vital:20326 , ISBN 0868100293
- Description: This initial attempt to compile a register of the various and numerous organisations in Grahamstown has been undertaken by the Albany branch of the National Council of Women. It has been my pleasure as president to research and edit this work. 1 must stress that this is neither complete nor all-embracing, but it was decided to publish now in order that the information which has presently been assembled be reasonably up to date. Where details concerning a particular society or group are scant a space has been left for interested readers to insert independently any additional information they are able to secure. Should the general public wish this to be an annual publication the NCW will be prepared to undertake the work. With this in mind I shall be most grateful to receive the details of any groups which have been inadvertently omitted as well as changed information regarding those groups which have been included. I hope that Grahamstonians will enjoy perusing this list of so many different kinds of involvement. It would be interesting to know whether we hold some kind of record in this regard. We are a small community, but most interests are represented and there is something for practically everyone. It is hoped that newcomers to the city will make use of this directory to make contact with the sporting club, service group or social association that best suits their interests and inclinations. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
- Full Text:
- Date Issued: 1980
- Authors: Henderson, Thelma M
- Date: 1980
- Subjects: Associations, institutions, etc. -- South Africa -- Grahamstown -- Directories Social service -- South Africa -- Grahamstown -- Directories Church buildings -- South Africa -- Grahamstown Community education -- South Africa -- Eastern Cape Sports -- South Africa -- South Africa -- Grahamstown Social service -- South Africa -- Grahamstown Charities -- South Africa -- Grahamstown Societies -- South Africa -- Grahamstown Grahamstown -- South Africa -- Social conditions
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/2790 , vital:20326 , ISBN 0868100293
- Description: This initial attempt to compile a register of the various and numerous organisations in Grahamstown has been undertaken by the Albany branch of the National Council of Women. It has been my pleasure as president to research and edit this work. 1 must stress that this is neither complete nor all-embracing, but it was decided to publish now in order that the information which has presently been assembled be reasonably up to date. Where details concerning a particular society or group are scant a space has been left for interested readers to insert independently any additional information they are able to secure. Should the general public wish this to be an annual publication the NCW will be prepared to undertake the work. With this in mind I shall be most grateful to receive the details of any groups which have been inadvertently omitted as well as changed information regarding those groups which have been included. I hope that Grahamstonians will enjoy perusing this list of so many different kinds of involvement. It would be interesting to know whether we hold some kind of record in this regard. We are a small community, but most interests are represented and there is something for practically everyone. It is hoped that newcomers to the city will make use of this directory to make contact with the sporting club, service group or social association that best suits their interests and inclinations. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
- Full Text:
- Date Issued: 1980
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