A holistic approach in understanding the effects of dietary protein sources on the growth and reproductive development of farmed abalone, Haliotis midae
- Wu, Yu
- Authors: Wu, Yu
- Date: 2020
- Subjects: Abalones -- Nutrition , Abalones -- Reproduction , Abalones -- Growth , Abalone culture , Haliotis midae -- Nutrition , Haliotis midae -- Reproduction , Haliotis midae -- Growth , Haliotis midae fisheries
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167719 , vital:41506
- Description: The combination of fishmeal and soya in the formulated feed of farmed South African abalone, Haliotis midae, not only improved abalone growth, but also the sustainability of the compound diets by reducing the reliance on fishmeal. However, the presence of soya produced larger gonads compared to those of abalone fed kelp or single-source protein diets. There is an increasing drive to control sexual maturation and reduce undesirable spawning events in farmed abalone. However, the reasons for the reported effects of soya inclusion on the reproductive development of farmed H. midae remain unresolved. The aim of this research was to use a combination of techniques to contribute to the understanding of the relationship between growth, reproductive and nutritional physiology of farmed H. midae fed diets of varying protein sources. These techniques included stable isotope analysis (SIA), fatty acid analysis, gonad histological assessments and haemolymph sexsteroid hormone analysis. The objectives were to examine the allocation of protein and nutritional components to somatic and reproductive tissues. This study also included the first attempt to investigate the role that sex steroid hormones play during gametogenesis. Abalone (40 – 50 g abalone-1) were fed one of four diets: either a single-source protein-based diet, i.e., (1) fishmeal-only (FM) or (2) soya-only (S), or a combination diet of (3) fishmeal-soya (FM S) or (4) fishmeal-sunflower meal (FM SM). Sampling occurred in 45-day intervals over one year. Dietary protein source had an effect on the growth of abalone, with enhancements in growth linked to the combination of fishmeal and a plant-protein source. The fishmeal ingredient was the most utilised protein source throughout the temporal changes in protein allocation into somatic and reproductive tissue, followed by soya and then sunflower meal. The mean whole- body mass of abalone was significantly influenced by an interaction between time and dietary treatment, with average whole-body mass changing differently over time between treatments (RM-ANOVA, F(24, 96) = 2.13, p = 0.005). Overall, abalone that were fed FM S had higher mean whole-body mass values than abalone that were fed the single-protein based diets, while abalone that were fed FM SM were similar to animals from all dietary treatments (RMANOVA, F(3, 12) = 5.75, p = 0.01). Male abalone had significantly higher gonad bulk index (GBI) values compared to females (RM-ANOVA, F(1, 24) = 49.03, p < 0.001) and this was independent of dietary treatment. Within each sex, female abalone fed the FM S diet (15.92 ± 1.88 mm3 g-1) had significantly higher GBI values than abalone fed S (9.76 ± 1.08 mm3 g-1), while abalone fed FM (11.96 ± 1.71 mm3 g-1) and FM SM (11.90 ± 0.80 mm3 g-1) were similar to abalone from all other dietary treatments (Tukey’s HSD, p < 0.05). Male abalone fed the FM S (21.59 ± 2.10 mm3 g-1) and FM SM diet (19.30 ± 2.63 mm3 g-1) had similar GBI values and they were significantly higher than in abalone fed the S diet (14.74 ± 1.27 mm3 g-1), while abalone fed FM S had significantly higher GBI values than abalone that consumed the FM diet (15.08 ±1.63mm3 g-1) ( Tukey’s HSD, p < 0.05). Although sunflower meal was poorly utilised, it produced similar overall growth to abalone that were fed the FM S diets. Yet, feed conversion ratio values were significantly lower for abalone fed FM S (1.30 ± 0.13) compared to those in the other three treatments, with ratios ranging from 1.65 – 1.72 over the one-year. The fatty acid compositions of the somatic and gonadal tissues were similar between treatments (PERMANOVA, p = 0.21), while fatty acid composition was influenced by sampling day, tissue type and abalone sex (PERMANOVA, p < 0.05). The essential fatty acids (EFAs) eicosadienoic acid and a-linolenic acid were present in abalone tissue, but they were not detected in the diets, suggesting the important role that an alternate food source (e.g. farmed abalone also had access to diatoms) may have played and the ability that H. midae may have in converting long-chain polyunsaturated fatty acids from C18 precursors. A change in the abundance of EFAs in the gonad tissue during highest and lowest GBI values suggested that arachidonic, eicosapentaenoic, g-linolenic and linoleic acid were important in females, while eicosapentaenoic, eicosadienoic and a-linolenic acid were important for male reproductive development. Dietary protein sources had an effect on the frequency distribution of maturity stages, where females that were fed FM S produced more ripe gonads and more males that were fed FM SM contained testes that showed signs of ripeness over the one-year study. Although dietary protein influenced the sex steroid concentrations in females and males, exhibiting fluctuations throughout the one-year period, no distinct pattern linked to gametogenesis were observed. The results from this study illustrate: (1) the importance of conducting laboratory studies when implementing SIA and mixing models in aquaculture nutrition; (2) conducting nutritional studies on mature, grow-out abalone; and (3) assessing the importance of naturally occurring diatoms in their diet and their contribution to growth and reproduction. The novel contribution of this research towards abalone nutritional physiology, the implications of these findings to industry as well as potential considerations for future studies were addressed.
- Full Text:
- Date Issued: 2020
- Authors: Wu, Yu
- Date: 2020
- Subjects: Abalones -- Nutrition , Abalones -- Reproduction , Abalones -- Growth , Abalone culture , Haliotis midae -- Nutrition , Haliotis midae -- Reproduction , Haliotis midae -- Growth , Haliotis midae fisheries
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167719 , vital:41506
- Description: The combination of fishmeal and soya in the formulated feed of farmed South African abalone, Haliotis midae, not only improved abalone growth, but also the sustainability of the compound diets by reducing the reliance on fishmeal. However, the presence of soya produced larger gonads compared to those of abalone fed kelp or single-source protein diets. There is an increasing drive to control sexual maturation and reduce undesirable spawning events in farmed abalone. However, the reasons for the reported effects of soya inclusion on the reproductive development of farmed H. midae remain unresolved. The aim of this research was to use a combination of techniques to contribute to the understanding of the relationship between growth, reproductive and nutritional physiology of farmed H. midae fed diets of varying protein sources. These techniques included stable isotope analysis (SIA), fatty acid analysis, gonad histological assessments and haemolymph sexsteroid hormone analysis. The objectives were to examine the allocation of protein and nutritional components to somatic and reproductive tissues. This study also included the first attempt to investigate the role that sex steroid hormones play during gametogenesis. Abalone (40 – 50 g abalone-1) were fed one of four diets: either a single-source protein-based diet, i.e., (1) fishmeal-only (FM) or (2) soya-only (S), or a combination diet of (3) fishmeal-soya (FM S) or (4) fishmeal-sunflower meal (FM SM). Sampling occurred in 45-day intervals over one year. Dietary protein source had an effect on the growth of abalone, with enhancements in growth linked to the combination of fishmeal and a plant-protein source. The fishmeal ingredient was the most utilised protein source throughout the temporal changes in protein allocation into somatic and reproductive tissue, followed by soya and then sunflower meal. The mean whole- body mass of abalone was significantly influenced by an interaction between time and dietary treatment, with average whole-body mass changing differently over time between treatments (RM-ANOVA, F(24, 96) = 2.13, p = 0.005). Overall, abalone that were fed FM S had higher mean whole-body mass values than abalone that were fed the single-protein based diets, while abalone that were fed FM SM were similar to animals from all dietary treatments (RMANOVA, F(3, 12) = 5.75, p = 0.01). Male abalone had significantly higher gonad bulk index (GBI) values compared to females (RM-ANOVA, F(1, 24) = 49.03, p < 0.001) and this was independent of dietary treatment. Within each sex, female abalone fed the FM S diet (15.92 ± 1.88 mm3 g-1) had significantly higher GBI values than abalone fed S (9.76 ± 1.08 mm3 g-1), while abalone fed FM (11.96 ± 1.71 mm3 g-1) and FM SM (11.90 ± 0.80 mm3 g-1) were similar to abalone from all other dietary treatments (Tukey’s HSD, p < 0.05). Male abalone fed the FM S (21.59 ± 2.10 mm3 g-1) and FM SM diet (19.30 ± 2.63 mm3 g-1) had similar GBI values and they were significantly higher than in abalone fed the S diet (14.74 ± 1.27 mm3 g-1), while abalone fed FM S had significantly higher GBI values than abalone that consumed the FM diet (15.08 ±1.63mm3 g-1) ( Tukey’s HSD, p < 0.05). Although sunflower meal was poorly utilised, it produced similar overall growth to abalone that were fed the FM S diets. Yet, feed conversion ratio values were significantly lower for abalone fed FM S (1.30 ± 0.13) compared to those in the other three treatments, with ratios ranging from 1.65 – 1.72 over the one-year. The fatty acid compositions of the somatic and gonadal tissues were similar between treatments (PERMANOVA, p = 0.21), while fatty acid composition was influenced by sampling day, tissue type and abalone sex (PERMANOVA, p < 0.05). The essential fatty acids (EFAs) eicosadienoic acid and a-linolenic acid were present in abalone tissue, but they were not detected in the diets, suggesting the important role that an alternate food source (e.g. farmed abalone also had access to diatoms) may have played and the ability that H. midae may have in converting long-chain polyunsaturated fatty acids from C18 precursors. A change in the abundance of EFAs in the gonad tissue during highest and lowest GBI values suggested that arachidonic, eicosapentaenoic, g-linolenic and linoleic acid were important in females, while eicosapentaenoic, eicosadienoic and a-linolenic acid were important for male reproductive development. Dietary protein sources had an effect on the frequency distribution of maturity stages, where females that were fed FM S produced more ripe gonads and more males that were fed FM SM contained testes that showed signs of ripeness over the one-year study. Although dietary protein influenced the sex steroid concentrations in females and males, exhibiting fluctuations throughout the one-year period, no distinct pattern linked to gametogenesis were observed. The results from this study illustrate: (1) the importance of conducting laboratory studies when implementing SIA and mixing models in aquaculture nutrition; (2) conducting nutritional studies on mature, grow-out abalone; and (3) assessing the importance of naturally occurring diatoms in their diet and their contribution to growth and reproduction. The novel contribution of this research towards abalone nutritional physiology, the implications of these findings to industry as well as potential considerations for future studies were addressed.
- Full Text:
- Date Issued: 2020
A housing affordability and tenure of choice quantum deliverable model in South Africa
- Authors: Kabundu, Emmanuel Kizito
- Date: 2020
- Subjects: Housing -- Prices -- South Africa Housing -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/49606 , vital:41740
- Description: The aim of this research was to develop a model that practically determines the tenure of choice and affordability of households in South Africa, which will thus help towards informed decision making by analysts and housing officials. Presently, there is no clear systematic means (except for simplistic ratios) of determining the degree of the effect of changes in the housing market (such as implemented policies) on the tenure of choice and affordability decisions of households. The research set out to improve upon the usage of ratios by basing its analysis on the theoretical underpinnings of both user costs of occupancy and an assumption of endogeneity between tenure of choice and affordability. The research used the general household survey data from Statistics South Africa for the analysis and validation. Generalized joint binary regression (on assumption of endogeneity between tenure of choice and affordability) was used as a check against the user costs of occupancy modelling. An independent market analysis carried out showed that South Africa has consistently faced increasing problems of acute housing shortages and housing affordability. Never the less, apart from subsidy programs, the option to promote renting, coupled with use of innovative building technologies showed promise of significantly alleviating these problems. More living space is especially more vital than ever, amid the current crisis of COVID-19 pademic. Statistical tests indicated strong evidence suggesting that the developed user costs of occupancy model (dynamic tenure model) is reliable at correctly recovering the tenure statuses of the households, with its recovery rates being better than those of the regression model. Both models provided useful unique, but different insights into the housing market and also correctly predicted the behavioural patterns of South African housing markets, such as significantly worsening affordability, and a market that is biased towards home ownership. The analysis also showed that affordability and tenure of choice were significantly affected by locational factors, household characteristics (such as race and age of household head), and most significantly, the age of the household head (which is a proxy to household income). The research successfully met its goal of model building but also recognized the need to merge these two models (dynamic tenure model and the regression model) into one model for more comprehensive housing related analysis. The research also recognized a need to fully operationalize the optimization, Monte Carlo and parallelization modules in order to improve the practical usefulness and effectiveness of the model. The significance of the study is that it it underpins the basis for proper tenure and affordability analysis, by assuming endogeneity between the two (2), and provides a modelling framework based on these criteria, that are useful for meaningful housing market analysis.
- Full Text:
- Date Issued: 2020
- Authors: Kabundu, Emmanuel Kizito
- Date: 2020
- Subjects: Housing -- Prices -- South Africa Housing -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/49606 , vital:41740
- Description: The aim of this research was to develop a model that practically determines the tenure of choice and affordability of households in South Africa, which will thus help towards informed decision making by analysts and housing officials. Presently, there is no clear systematic means (except for simplistic ratios) of determining the degree of the effect of changes in the housing market (such as implemented policies) on the tenure of choice and affordability decisions of households. The research set out to improve upon the usage of ratios by basing its analysis on the theoretical underpinnings of both user costs of occupancy and an assumption of endogeneity between tenure of choice and affordability. The research used the general household survey data from Statistics South Africa for the analysis and validation. Generalized joint binary regression (on assumption of endogeneity between tenure of choice and affordability) was used as a check against the user costs of occupancy modelling. An independent market analysis carried out showed that South Africa has consistently faced increasing problems of acute housing shortages and housing affordability. Never the less, apart from subsidy programs, the option to promote renting, coupled with use of innovative building technologies showed promise of significantly alleviating these problems. More living space is especially more vital than ever, amid the current crisis of COVID-19 pademic. Statistical tests indicated strong evidence suggesting that the developed user costs of occupancy model (dynamic tenure model) is reliable at correctly recovering the tenure statuses of the households, with its recovery rates being better than those of the regression model. Both models provided useful unique, but different insights into the housing market and also correctly predicted the behavioural patterns of South African housing markets, such as significantly worsening affordability, and a market that is biased towards home ownership. The analysis also showed that affordability and tenure of choice were significantly affected by locational factors, household characteristics (such as race and age of household head), and most significantly, the age of the household head (which is a proxy to household income). The research successfully met its goal of model building but also recognized the need to merge these two models (dynamic tenure model and the regression model) into one model for more comprehensive housing related analysis. The research also recognized a need to fully operationalize the optimization, Monte Carlo and parallelization modules in order to improve the practical usefulness and effectiveness of the model. The significance of the study is that it it underpins the basis for proper tenure and affordability analysis, by assuming endogeneity between the two (2), and provides a modelling framework based on these criteria, that are useful for meaningful housing market analysis.
- Full Text:
- Date Issued: 2020
A lean production approach to materials management in the Nigerian construction industry
- Authors: Albert, Idowu
- Date: 2020
- Subjects: Materials management , Lean manufacturing Construction industry -- Nigeria
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46008 , vital:39408
- Description: The Nigerian Construction Industry faces a problem of poor materials management that leads to, among other things, materials waste, poor quality of work, poor materials flow, project delay and cost overrun. Overcoming these challenges, requires the rethinking the current modus operandi of the Nigerian construction industry. One such method that has been espoused as having potential to improve materials management, and associated challenges is ‘lean production’. This research aimed at deciphering the lean approach to production management with a view of extracting its utility in enhancing materials management in the construction industry. The qualitative method of research inquiry that is rooted in the phenomenological paradigm was employed. The research activities included a comprehensive review of the related literature and study of selected cases. Abuja, the Federal capital territory of Nigeria was the selected geographical scope of the research. Ten case studies were purposefully selected for the study. The research instrument was a tick box used for direct observation. The study revealed that poor materials management has a negative effect on the materials management plan. Moreover, mixing of waste at the site, negates the effort for identification of materials waste streams, and makes it difficult to account for materials waste, as well as implementing a materials waste management policy on sites. The research also found that poor materials management has a significant effect (high, moderate or low) on materials waste, quality of work, materials flow, productivity, project delay, project profitability and accounting for materials. The research has developed a conceptual model for a lean production approach to materials management based on the results and informed by the theoretical framework. The study has achieved its aim of establishing an understanding of the lean production approach to materials management in the Nigerian construction industry. The study recommends that construction professionals should be well informed on the effects of poor materials management.
- Full Text:
- Date Issued: 2020
- Authors: Albert, Idowu
- Date: 2020
- Subjects: Materials management , Lean manufacturing Construction industry -- Nigeria
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46008 , vital:39408
- Description: The Nigerian Construction Industry faces a problem of poor materials management that leads to, among other things, materials waste, poor quality of work, poor materials flow, project delay and cost overrun. Overcoming these challenges, requires the rethinking the current modus operandi of the Nigerian construction industry. One such method that has been espoused as having potential to improve materials management, and associated challenges is ‘lean production’. This research aimed at deciphering the lean approach to production management with a view of extracting its utility in enhancing materials management in the construction industry. The qualitative method of research inquiry that is rooted in the phenomenological paradigm was employed. The research activities included a comprehensive review of the related literature and study of selected cases. Abuja, the Federal capital territory of Nigeria was the selected geographical scope of the research. Ten case studies were purposefully selected for the study. The research instrument was a tick box used for direct observation. The study revealed that poor materials management has a negative effect on the materials management plan. Moreover, mixing of waste at the site, negates the effort for identification of materials waste streams, and makes it difficult to account for materials waste, as well as implementing a materials waste management policy on sites. The research also found that poor materials management has a significant effect (high, moderate or low) on materials waste, quality of work, materials flow, productivity, project delay, project profitability and accounting for materials. The research has developed a conceptual model for a lean production approach to materials management based on the results and informed by the theoretical framework. The study has achieved its aim of establishing an understanding of the lean production approach to materials management in the Nigerian construction industry. The study recommends that construction professionals should be well informed on the effects of poor materials management.
- Full Text:
- Date Issued: 2020
A leopard's favourite spots: habitat preference and population density of leopards in a semi-arid biodiversity hotspot
- Mann, Gareth K H, O'Riain, M Justin, Parker, Daniel M
- Authors: Mann, Gareth K H , O'Riain, M Justin , Parker, Daniel M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148584 , vital:38752 , https://doi.org/10.1016/j.jaridenv.2020.104218
- Description: Leopards (Panthera pardus) are the only free-ranging large predators to still occur naturally throughout much of Africa, but are vulnerable to habitat loss, ecosystem degradation and persecution. We used a systematic camera trap survey covering an area of ∼3100 km2 in the Little Karoo, a semi-arid biodiversity hotspot in South Africa, to assess the impacts of land use and habitat type on leopard density. Camera data were supplemented by opportunistic scat collection to produce a habitat suitability model. We used a habitat suitability model to inform spatially explicit capture-recapture models used to estimate population density. We recorded 152 independent photographs of 27 individually recognizable leopards at 54 camera stations and collected scats from a further 76 locations. Our habitat suitability model showed that primary productivity and vegetation type were the best predictors of leopard habitat suitability. Our best performing population density model allowed for detection and movement of individuals to vary according to sex, and estimated population density at 1.26 (SE ± 0.25) leopards/100 km2.
- Full Text:
- Date Issued: 2020
- Authors: Mann, Gareth K H , O'Riain, M Justin , Parker, Daniel M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148584 , vital:38752 , https://doi.org/10.1016/j.jaridenv.2020.104218
- Description: Leopards (Panthera pardus) are the only free-ranging large predators to still occur naturally throughout much of Africa, but are vulnerable to habitat loss, ecosystem degradation and persecution. We used a systematic camera trap survey covering an area of ∼3100 km2 in the Little Karoo, a semi-arid biodiversity hotspot in South Africa, to assess the impacts of land use and habitat type on leopard density. Camera data were supplemented by opportunistic scat collection to produce a habitat suitability model. We used a habitat suitability model to inform spatially explicit capture-recapture models used to estimate population density. We recorded 152 independent photographs of 27 individually recognizable leopards at 54 camera stations and collected scats from a further 76 locations. Our habitat suitability model showed that primary productivity and vegetation type were the best predictors of leopard habitat suitability. Our best performing population density model allowed for detection and movement of individuals to vary according to sex, and estimated population density at 1.26 (SE ± 0.25) leopards/100 km2.
- Full Text:
- Date Issued: 2020
A management model for human settlements: a case study of Nigeria and South Africa
- Authors: Adeniran, Adeleye Ayoade
- Date: 2020
- Subjects: Human settlements -- Nigeria , Human settlements -- South Africa Sustainable development
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/45985 , vital:39403
- Description: Persistent depreciating human settlements is a global challenge, particularly in developing countries and this challenge contributes to the continuously increasing housing gap, despite several novel policies and programmes. Although there is a dearth of research-based literature on human settlements management, studies show that property management, Facility Management, housing management and urban management impact the sustainability of all these built environment milieus which form part of the human settlements’ sub-components. This research aimed at altering the afore-said challenge by exploring the management of human settlements in Nigeria and in South Africa. Philosophically, the research is pragmatic, and it rests on positivist deductive reasoning. The methods used for data collection include a review of literature, collection of archival records, and empirical studies of purposively selected professionals and stakeholders involved in human settlements’ management in Nigeria and in South Africa. The findings indicate that existing human settlements in the case studies are “good” and “acceptable” with the majority adopting an outsourced method of management. Furthermore, the lack of maintenance records, the deficiency in policy monitoring and the training of management and maintenance personnel were the three highest ranking factors indicated to be affecting human settlements management. Moreover, an inhabitant’s income, the time available for management, professional expertise and technology employed for management are recognised as the critical sustainability sub-factors affecting human settlement management. The factor analysis established ownership, human resource and capital, social, legal, technology, economic, physical and environmental factors as vital and very significant in achieving sustainable management of human settlements. The study recommends the professionalisation of the field of human settlements as well as a formulation of management policy among others. The study developed a management model for human settlements, and it advocates that human settlements managers, owners and organisations should apply the model in this study, to improve their human settlement management practices, so as to achieve sustainability, and in essence, Sustainable Development Goal 11. It is hoped that the suggested management model will influence human settlement policy development and review, the designing of human settlement management programmes including the framework for their ongoing monitoring and evaluation. The study furthermore contributes to the development of housing and human settlement curricula and evolving human settlement research in both developed and developing countries.
- Full Text:
- Date Issued: 2020
- Authors: Adeniran, Adeleye Ayoade
- Date: 2020
- Subjects: Human settlements -- Nigeria , Human settlements -- South Africa Sustainable development
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/45985 , vital:39403
- Description: Persistent depreciating human settlements is a global challenge, particularly in developing countries and this challenge contributes to the continuously increasing housing gap, despite several novel policies and programmes. Although there is a dearth of research-based literature on human settlements management, studies show that property management, Facility Management, housing management and urban management impact the sustainability of all these built environment milieus which form part of the human settlements’ sub-components. This research aimed at altering the afore-said challenge by exploring the management of human settlements in Nigeria and in South Africa. Philosophically, the research is pragmatic, and it rests on positivist deductive reasoning. The methods used for data collection include a review of literature, collection of archival records, and empirical studies of purposively selected professionals and stakeholders involved in human settlements’ management in Nigeria and in South Africa. The findings indicate that existing human settlements in the case studies are “good” and “acceptable” with the majority adopting an outsourced method of management. Furthermore, the lack of maintenance records, the deficiency in policy monitoring and the training of management and maintenance personnel were the three highest ranking factors indicated to be affecting human settlements management. Moreover, an inhabitant’s income, the time available for management, professional expertise and technology employed for management are recognised as the critical sustainability sub-factors affecting human settlement management. The factor analysis established ownership, human resource and capital, social, legal, technology, economic, physical and environmental factors as vital and very significant in achieving sustainable management of human settlements. The study recommends the professionalisation of the field of human settlements as well as a formulation of management policy among others. The study developed a management model for human settlements, and it advocates that human settlements managers, owners and organisations should apply the model in this study, to improve their human settlement management practices, so as to achieve sustainability, and in essence, Sustainable Development Goal 11. It is hoped that the suggested management model will influence human settlement policy development and review, the designing of human settlement management programmes including the framework for their ongoing monitoring and evaluation. The study furthermore contributes to the development of housing and human settlement curricula and evolving human settlement research in both developed and developing countries.
- Full Text:
- Date Issued: 2020
A mathematics teacher's response to a dilemma: 'I'm supposed to teach them in English but they don't understand'
- Robertson, Sally-Ann, Graven, Mellony
- Authors: Robertson, Sally-Ann , Graven, Mellony
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148889 , vital:38783 , https://doi.org/10.4102/sajce.v10i1.800
- Description: English is the dominant language in South African schools although it is the home language for less than 10% of the population. Many schools have yet to embrace the Language in Education Policy’s advocacy of additive bilingualism. This has led to a majority of the country’s children learning and being assessed through a language in which they lack proficiency. This article draws on second language teaching and learning theory to make a case for more systematic support for learners’ second language development and for legitimation of use of home language in mathematics classrooms where a different language is the official medium. The article shares empirical data from a South African Grade 4 mathematics teacher’s classroom to illuminate arguments in favour of additive bilingualism.
- Full Text:
- Date Issued: 2020
- Authors: Robertson, Sally-Ann , Graven, Mellony
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148889 , vital:38783 , https://doi.org/10.4102/sajce.v10i1.800
- Description: English is the dominant language in South African schools although it is the home language for less than 10% of the population. Many schools have yet to embrace the Language in Education Policy’s advocacy of additive bilingualism. This has led to a majority of the country’s children learning and being assessed through a language in which they lack proficiency. This article draws on second language teaching and learning theory to make a case for more systematic support for learners’ second language development and for legitimation of use of home language in mathematics classrooms where a different language is the official medium. The article shares empirical data from a South African Grade 4 mathematics teacher’s classroom to illuminate arguments in favour of additive bilingualism.
- Full Text:
- Date Issued: 2020
A mixed methods investigation of students’ attitudes towards statistics and quantitative research methods: a focus on postgraduate psychology students at a South African university
- Authors: Ngantweni, Xolelwa
- Date: 2020
- Subjects: Fetal alcohol spectrum disorders -- South Africa , Statistics , Psychology -- Research , College students -- South Africa -- Attitudes , Psychology -- Research -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140490 , vital:37894
- Description: Many University programs offer a course in either basic or intermediate statistics as part of the degree requirements prior to graduation (McGrath, Ferns, Greiner, Wanamaker and Brown, 2015). These statistics or quantitative research methods courses are integral in helping students gain vital skills in analysing quantitative data. Research (Schau, Stevens, Dauphinee, and Del Vecchio, 1995) does however indicate that most students have a perfunctory disposition towards these courses. My study sought to particularly investigate attitudes towards statistics and quantitative research methods amongst a sample of 61 postgraduate Psychology students at Rhodes University undertaking a ‘Quantitative Research Methods’ course as part of their degree offering. A mixed methods approach was used to investigate students’ attitudes towards statistics and quantitative research methods. The Survey of Attitudes Toward Statistics (SATS-36) (Schau, 2003) captured student’s attitudes towards statistics using a Likert Scale instrument; whereas detailed qualitative interviews accentuated findings from the SATS-36. Key quantitative findings from the SATS-36 including students’ perceptions of statistics being a difficult course as well as students having a low affect towards statistics are detailed. Key qualitative findings related to why students experience statistics anxiety such as students’ (1) fear of failing statistics, (2) The late introduction of statistics in the Psychology curriculum, and (3) The role of educator/s in alleviating or promoting feelings of statistics anxiety are noted. The significance of these findings as well as the contributions of the study to the teaching and learning of statistics and quantitative research methods courses at Rhodes University are explored, in light of other studies on the topic of statistics anxiety and attitudes towards statistics/ quantitative research methods.
- Full Text:
- Date Issued: 2020
- Authors: Ngantweni, Xolelwa
- Date: 2020
- Subjects: Fetal alcohol spectrum disorders -- South Africa , Statistics , Psychology -- Research , College students -- South Africa -- Attitudes , Psychology -- Research -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/140490 , vital:37894
- Description: Many University programs offer a course in either basic or intermediate statistics as part of the degree requirements prior to graduation (McGrath, Ferns, Greiner, Wanamaker and Brown, 2015). These statistics or quantitative research methods courses are integral in helping students gain vital skills in analysing quantitative data. Research (Schau, Stevens, Dauphinee, and Del Vecchio, 1995) does however indicate that most students have a perfunctory disposition towards these courses. My study sought to particularly investigate attitudes towards statistics and quantitative research methods amongst a sample of 61 postgraduate Psychology students at Rhodes University undertaking a ‘Quantitative Research Methods’ course as part of their degree offering. A mixed methods approach was used to investigate students’ attitudes towards statistics and quantitative research methods. The Survey of Attitudes Toward Statistics (SATS-36) (Schau, 2003) captured student’s attitudes towards statistics using a Likert Scale instrument; whereas detailed qualitative interviews accentuated findings from the SATS-36. Key quantitative findings from the SATS-36 including students’ perceptions of statistics being a difficult course as well as students having a low affect towards statistics are detailed. Key qualitative findings related to why students experience statistics anxiety such as students’ (1) fear of failing statistics, (2) The late introduction of statistics in the Psychology curriculum, and (3) The role of educator/s in alleviating or promoting feelings of statistics anxiety are noted. The significance of these findings as well as the contributions of the study to the teaching and learning of statistics and quantitative research methods courses at Rhodes University are explored, in light of other studies on the topic of statistics anxiety and attitudes towards statistics/ quantitative research methods.
- Full Text:
- Date Issued: 2020
A model for the detection of breast cancer using machine learning and thermal images in a mobile environment
- Authors: Lennox, Nicholas
- Date: 2020
- Subjects: Breast -- Cancer -- Imaging , Breast -- Imaging Mobile communication systems
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/46097 , vital:39492
- Description: Breast cancer is the most common cancer amongst women and one of the deadliest. Various modalities exist which image the breasts, all with a focus on early detection; thermography is one such method. It is a non-invasive test, which is safe and can be used for a wide variety of breast densities. It functions by analysing thermal patterns captured via an infrared camera of the surface of the breast. Advances in infrared and mobile technology enable this modality to be mobile based; allowing a high degree of portability at a lower cost. Furthermore, as technology has improved, machine learning has played a larger role in medical practices by offering unbiased, consistent, and timely second opinions. Machine learning algorithms are able to classify medical images automatically if offered in the correct format. This study aims to provide a model, which integrates breast cancer detection, thermal imaging, machine learning, and mobile technology. The conceptual model is theorised from three literature studies regarding: identifiable aspects of breast cancer through thermal imaging, the mobile ecosystem, and classification using machine learning algorithms. The model is implemented and evaluated using an experiment designed to classify automatically thermal breast images of the same quality that mobile attachable thermal cameras are able to capture. The experiment contrasts various combinations of segmentation methods, extracted features, and classification algorithms. Promising results were shown in the experiment with a high degree of accuracy obtained. The successful results obtained from the experimentation process validates the feasibility of the model.
- Full Text:
- Date Issued: 2020
- Authors: Lennox, Nicholas
- Date: 2020
- Subjects: Breast -- Cancer -- Imaging , Breast -- Imaging Mobile communication systems
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/46097 , vital:39492
- Description: Breast cancer is the most common cancer amongst women and one of the deadliest. Various modalities exist which image the breasts, all with a focus on early detection; thermography is one such method. It is a non-invasive test, which is safe and can be used for a wide variety of breast densities. It functions by analysing thermal patterns captured via an infrared camera of the surface of the breast. Advances in infrared and mobile technology enable this modality to be mobile based; allowing a high degree of portability at a lower cost. Furthermore, as technology has improved, machine learning has played a larger role in medical practices by offering unbiased, consistent, and timely second opinions. Machine learning algorithms are able to classify medical images automatically if offered in the correct format. This study aims to provide a model, which integrates breast cancer detection, thermal imaging, machine learning, and mobile technology. The conceptual model is theorised from three literature studies regarding: identifiable aspects of breast cancer through thermal imaging, the mobile ecosystem, and classification using machine learning algorithms. The model is implemented and evaluated using an experiment designed to classify automatically thermal breast images of the same quality that mobile attachable thermal cameras are able to capture. The experiment contrasts various combinations of segmentation methods, extracted features, and classification algorithms. Promising results were shown in the experiment with a high degree of accuracy obtained. The successful results obtained from the experimentation process validates the feasibility of the model.
- Full Text:
- Date Issued: 2020
A morphogenetic study of ESD inclusion in Namibia’s Senior Primary English curriculum: a case study of the Khomas Region
- Authors: Malua, Anelly Ndapewa
- Date: 2020
- Subjects: Sustanable development -- Study and teaching -- Namibia , Environmental education -- Namibia , English language -- Study and teaching (Elementary) -- Namibia , Schools -- Namibia -- Curricula , Social change
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142865 , vital:38124
- Description: Education policies are designed to structure and direct the content and process of the education that citizens receive. This includes the advancement of the Education for Sustainable Development (ESD) policy in formal school curricula. If effectively implemented, ESD can be a significant educational intervention in southern African countries’ development trajectories. ESD incorporates the environmental, social and economic pillars of Sustainable Development and it has the potential to curb issues such as poverty reduction, climate change, biodiversity loss and unsustainable patterns of consumption and production. This qualitative case study investigated factors that have historically shaped, and currently shape, the emergence of ESD implementation in the Senior Primary English curriculum in the Khomas Region of Namibia. As a critical realist enquiry, the study sought to go beyond interpretations of the empirical to identify causal mechanisms in the domains of ‘the actual’ and ‘the real’. The study was guided by Margaret Archer’s theory of Morphogenesis / Morphostasis and her methodological tool of ‘analytical dualism’. The case record consisted of educational documents, teacher questionnaires and semistructured interviews. The morphogenetic approach highlighted how the implementation of ESD through the Senior Primary English curriculum from 1990 to 2018 was conditioned by the interplay of social and cultural structures and mechanisms and human agency, particularly teachers’ agency. The study revealed that although ESD implementation has emerged in the Senior Primary English curriculum, its emergence is not synchronous with the structural and agential entities. The findings point to a policy-structure mismatch which has relevance for policy makers, practitioners and other ESD stakeholders. The significance of this study is that it stands to fill a research gap regarding ESD implementation in Namibia’s Senior Primary English curriculum. The study makes recommendations for tangible ways to strengthen ESD practice in Senior Primary English teaching in Namibia such as increasing professional development opportunities to orientate teachers to ESD, strengthening networks that can build teacher agency in relation to ESD, and promoting a theme-based approach to ESD practice in English Language teaching.
- Full Text:
- Date Issued: 2020
- Authors: Malua, Anelly Ndapewa
- Date: 2020
- Subjects: Sustanable development -- Study and teaching -- Namibia , Environmental education -- Namibia , English language -- Study and teaching (Elementary) -- Namibia , Schools -- Namibia -- Curricula , Social change
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/142865 , vital:38124
- Description: Education policies are designed to structure and direct the content and process of the education that citizens receive. This includes the advancement of the Education for Sustainable Development (ESD) policy in formal school curricula. If effectively implemented, ESD can be a significant educational intervention in southern African countries’ development trajectories. ESD incorporates the environmental, social and economic pillars of Sustainable Development and it has the potential to curb issues such as poverty reduction, climate change, biodiversity loss and unsustainable patterns of consumption and production. This qualitative case study investigated factors that have historically shaped, and currently shape, the emergence of ESD implementation in the Senior Primary English curriculum in the Khomas Region of Namibia. As a critical realist enquiry, the study sought to go beyond interpretations of the empirical to identify causal mechanisms in the domains of ‘the actual’ and ‘the real’. The study was guided by Margaret Archer’s theory of Morphogenesis / Morphostasis and her methodological tool of ‘analytical dualism’. The case record consisted of educational documents, teacher questionnaires and semistructured interviews. The morphogenetic approach highlighted how the implementation of ESD through the Senior Primary English curriculum from 1990 to 2018 was conditioned by the interplay of social and cultural structures and mechanisms and human agency, particularly teachers’ agency. The study revealed that although ESD implementation has emerged in the Senior Primary English curriculum, its emergence is not synchronous with the structural and agential entities. The findings point to a policy-structure mismatch which has relevance for policy makers, practitioners and other ESD stakeholders. The significance of this study is that it stands to fill a research gap regarding ESD implementation in Namibia’s Senior Primary English curriculum. The study makes recommendations for tangible ways to strengthen ESD practice in Senior Primary English teaching in Namibia such as increasing professional development opportunities to orientate teachers to ESD, strengthening networks that can build teacher agency in relation to ESD, and promoting a theme-based approach to ESD practice in English Language teaching.
- Full Text:
- Date Issued: 2020
A multimodal analysis of the representations of gender in contemporary South African children’s picture books produced by Book Dash
- Authors: Heydenrych, Ellen Frances
- Date: 2020
- Subjects: Book Dash (South Africa) , Picture books for children -- South Africa , Sex role in literature , Patriarchy in literature , Children's literature, South African (English) -- 21st century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/164284 , vital:41106
- Description: In response to a demand for quality children’s picture books written and published by South Africans for local children, Book Dash – a South African non-profit organisation – has devised a publishing model in which they produce high quality children’s picture books in a twelve-hour period. Their aim is to publish books that represent a diverse range of South African children. However, while their objective is to create books that are representative of many races, this representation happens through gendered characters. In this thesis, I explore the representation of gender in Book Dash’s picture books. I use a combination of visual social semiotics, narrative theory, and critical discourse analysis, specifically focusing on the gendered ways in which the characters are represented. My analysis of these books shows how complex it can be to contest regimes of representation that work to fix patriarchal discourses and gender inequality. My findings reveal a paradox in the representation of gender norms in female characters, as some girl child characters are represented in roles that challenge gender norms, while female adult characters are consistently represented as conforming to the patriarchal feminine ideal. There is also a notable lack of father figures in these books. Such portrayals may contribute to the perpetuation of patriarchal discourses and gender inequality, particularly if these books are held up as examples of equality.
- Full Text:
- Date Issued: 2020
- Authors: Heydenrych, Ellen Frances
- Date: 2020
- Subjects: Book Dash (South Africa) , Picture books for children -- South Africa , Sex role in literature , Patriarchy in literature , Children's literature, South African (English) -- 21st century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/164284 , vital:41106
- Description: In response to a demand for quality children’s picture books written and published by South Africans for local children, Book Dash – a South African non-profit organisation – has devised a publishing model in which they produce high quality children’s picture books in a twelve-hour period. Their aim is to publish books that represent a diverse range of South African children. However, while their objective is to create books that are representative of many races, this representation happens through gendered characters. In this thesis, I explore the representation of gender in Book Dash’s picture books. I use a combination of visual social semiotics, narrative theory, and critical discourse analysis, specifically focusing on the gendered ways in which the characters are represented. My analysis of these books shows how complex it can be to contest regimes of representation that work to fix patriarchal discourses and gender inequality. My findings reveal a paradox in the representation of gender norms in female characters, as some girl child characters are represented in roles that challenge gender norms, while female adult characters are consistently represented as conforming to the patriarchal feminine ideal. There is also a notable lack of father figures in these books. Such portrayals may contribute to the perpetuation of patriarchal discourses and gender inequality, particularly if these books are held up as examples of equality.
- Full Text:
- Date Issued: 2020
A multinational study of authors’ perceptions of and practical approaches to writing geography textbooks:
- Lee, Jongwon, Catling, Simon, Kidman, Gillian, Bednarz, Robert, Krause, Uwe, Martija, Andoni A, Ohnishi, Koji, Wilmot, P Dianne, Zecha, Stefane
- Authors: Lee, Jongwon , Catling, Simon , Kidman, Gillian , Bednarz, Robert , Krause, Uwe , Martija, Andoni A , Ohnishi, Koji , Wilmot, P Dianne , Zecha, Stefane
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158269 , vital:40168 , https://doi.org/10.1080/10382046.2020.1743931
- Description: Like all school textbooks, geography textbooks are authored. Almost all textbook research in and beyond geography has neglected their authors. This questionnaire-based multinational research project investigated the perceptions of 71 primary and secondary school geography textbook authors from seven countries in five continents. Though not intended as a definitive study, the findings identified several values and areas of expertise which many textbook authors in different countries held to be important for their work.
- Full Text:
- Date Issued: 2020
- Authors: Lee, Jongwon , Catling, Simon , Kidman, Gillian , Bednarz, Robert , Krause, Uwe , Martija, Andoni A , Ohnishi, Koji , Wilmot, P Dianne , Zecha, Stefane
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158269 , vital:40168 , https://doi.org/10.1080/10382046.2020.1743931
- Description: Like all school textbooks, geography textbooks are authored. Almost all textbook research in and beyond geography has neglected their authors. This questionnaire-based multinational research project investigated the perceptions of 71 primary and secondary school geography textbook authors from seven countries in five continents. Though not intended as a definitive study, the findings identified several values and areas of expertise which many textbook authors in different countries held to be important for their work.
- Full Text:
- Date Issued: 2020
A new approach to the biological monitoring of freshwater systems: Mapping nutrient loading in two South African rivers, a case study
- Motitsoe, Samuel N, Hill, Martin P, Avery, Trevor S, Hill, Jaclyn M
- Authors: Motitsoe, Samuel N , Hill, Martin P , Avery, Trevor S , Hill, Jaclyn M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444480 , vital:74244 , https://doi.org/10.1016/j.watres.2019.115391
- Description: Excessive addition of nitrogen (N) has threatened aquatic ecosystems for decades. Traditional water quality and biological monitoring assessment tools are widely used for monitoring nutrient loads and ecosystem health, but most of these methods cannot distinguish between different types and sources of pollution. This is a challenge, particularly when dealing with non-point sources of anthropogenic nitrogen inputs into freshwater systems. Recent laboratory studies using stable isotopic ratios (δ15N and C/N) of aquatic macrophytes (duckweed: Spirodela spp.) have shown successful differentiation and mapping between different N-sources and further, showed abilities to act as early warning indicators for environmental N-loading. Therefore, the aim of this study was to field test the potential of stable isotopic values of transplanted Spirodela spp. to map temporal and spatial N-loading variation and determine the main sources of N-loading in two river systems in the Eastern Cape Province of South Africa, using previously grown, isotopically calibrated and transplanted Spirodela plants, collected over a 13-month sampling period.
- Full Text:
- Date Issued: 2020
- Authors: Motitsoe, Samuel N , Hill, Martin P , Avery, Trevor S , Hill, Jaclyn M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444480 , vital:74244 , https://doi.org/10.1016/j.watres.2019.115391
- Description: Excessive addition of nitrogen (N) has threatened aquatic ecosystems for decades. Traditional water quality and biological monitoring assessment tools are widely used for monitoring nutrient loads and ecosystem health, but most of these methods cannot distinguish between different types and sources of pollution. This is a challenge, particularly when dealing with non-point sources of anthropogenic nitrogen inputs into freshwater systems. Recent laboratory studies using stable isotopic ratios (δ15N and C/N) of aquatic macrophytes (duckweed: Spirodela spp.) have shown successful differentiation and mapping between different N-sources and further, showed abilities to act as early warning indicators for environmental N-loading. Therefore, the aim of this study was to field test the potential of stable isotopic values of transplanted Spirodela spp. to map temporal and spatial N-loading variation and determine the main sources of N-loading in two river systems in the Eastern Cape Province of South Africa, using previously grown, isotopically calibrated and transplanted Spirodela plants, collected over a 13-month sampling period.
- Full Text:
- Date Issued: 2020
A new genus and three new species of South African Cicadettini (Hemiptera Cicadidae Cicadettinae).
- Sanborn, Allen F, Villet, Martin H
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441261 , vital:73871 , https://www.mapress.com/zt/article/view/zootaxa.4885.4.7
- Description: Ingcainyenzane irhiniensis n. gen., n. sp. and Ingcainyenzane nolukhanyoensis n. gen., n. sp. are described from Eastern Cape and Ingcainyenzane umgeniensis n. gen., n. sp. is described from KwaZulu-Natal, South Africa. Notes on its biology of the species and a key to species of the genus are also provided.
- Full Text:
- Date Issued: 2020
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441261 , vital:73871 , https://www.mapress.com/zt/article/view/zootaxa.4885.4.7
- Description: Ingcainyenzane irhiniensis n. gen., n. sp. and Ingcainyenzane nolukhanyoensis n. gen., n. sp. are described from Eastern Cape and Ingcainyenzane umgeniensis n. gen., n. sp. is described from KwaZulu-Natal, South Africa. Notes on its biology of the species and a key to species of the genus are also provided.
- Full Text:
- Date Issued: 2020
A new indole alkaloid and other constituents from Monodora minor and Uvaria tanzaniae: their antitrypanosomal and antiplasmodial evaluation
- Christopher, Robert, Mgani, Quintino A, Nyandoro, Stephen S, Rousseau, Amanda L, Isaacs, Michelle, Hoppe, Heinrich C
- Authors: Christopher, Robert , Mgani, Quintino A , Nyandoro, Stephen S , Rousseau, Amanda L , Isaacs, Michelle , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429347 , vital:72603 , xlink:href="https://doi.org/10.1080/14786419.2019.1710705"
- Description: Phytochemical investigation of the methanolic extract of Monodora minor Engl. and Diels (Annonaceae) stem bark yielded a new indole (E)-4-(1H-indol-5-yl)-but-3-en-2-one (1), a known indole 5-formyl-1H-indole (2) and an ubiquitous steroid sitosterol (3). The investigations of the methanolic extract of Uvaria tanzaniae Verdc. (Annonaceae) root bark yielded two previously reported C-benzylated dihydrochalcones namely uvaretin (4) and diuvaretin (5). Structures of the isolated compounds were elucidated based on NMR spectroscopy and high resolution electron ionization mass spectrometry (HR-EI-MS) data. All compounds were tested against Trypanosoma brucei brucei and Plasmodium falciparum. At a single concentration (20 μM) in the antitrypanosomal and antiplasmodial assays, compound 4 exhibited remarkable activities against T. brucei brucei and P. falciparum with percentage inhibition of 97.3% and 83.0% respectively, whereas compounds 1, 2, 3 and 5 were inactive. In a dose response antiplasmodial assay compound 4 exhibited moderate activity against P. falciparum with an IC50 value of 7.20 μM.
- Full Text:
- Date Issued: 2020
- Authors: Christopher, Robert , Mgani, Quintino A , Nyandoro, Stephen S , Rousseau, Amanda L , Isaacs, Michelle , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429347 , vital:72603 , xlink:href="https://doi.org/10.1080/14786419.2019.1710705"
- Description: Phytochemical investigation of the methanolic extract of Monodora minor Engl. and Diels (Annonaceae) stem bark yielded a new indole (E)-4-(1H-indol-5-yl)-but-3-en-2-one (1), a known indole 5-formyl-1H-indole (2) and an ubiquitous steroid sitosterol (3). The investigations of the methanolic extract of Uvaria tanzaniae Verdc. (Annonaceae) root bark yielded two previously reported C-benzylated dihydrochalcones namely uvaretin (4) and diuvaretin (5). Structures of the isolated compounds were elucidated based on NMR spectroscopy and high resolution electron ionization mass spectrometry (HR-EI-MS) data. All compounds were tested against Trypanosoma brucei brucei and Plasmodium falciparum. At a single concentration (20 μM) in the antitrypanosomal and antiplasmodial assays, compound 4 exhibited remarkable activities against T. brucei brucei and P. falciparum with percentage inhibition of 97.3% and 83.0% respectively, whereas compounds 1, 2, 3 and 5 were inactive. In a dose response antiplasmodial assay compound 4 exhibited moderate activity against P. falciparum with an IC50 value of 7.20 μM.
- Full Text:
- Date Issued: 2020
A novel dimeric exoglucanase (GH5_38)
- Mafa, Mpho S, Dirr, Heinrich W, Malgas, Samkelo, Krause, Rui W M, Pletschke, Brett I
- Authors: Mafa, Mpho S , Dirr, Heinrich W , Malgas, Samkelo , Krause, Rui W M , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193976 , vital:45412 , xlink:href="https://doi.org/10.3390/molecules25030746"
- Description: An exoglucanase (Exg-D) from the glycoside hydrolase family 5 subfamily 38 (GH5_38) was heterologously expressed and structurally and biochemically characterised at a molecular level for its application in alkyl glycoside synthesis. The purified Exg-D existed in both dimeric and monomeric forms in solution, which showed highest activity on mixed-linked β-glucan (88.0 and 86.7 U/mg protein, respectively) and lichenin (24.5 and 23.7 U/mg protein, respectively). They displayed a broad optimum pH range from 5.5 to 7 and a temperature optimum from 40 to 60 °C. Kinetic studies demonstrated that Exg-D had a higher affinity towards β-glucan, with a Km of 7.9 mg/mL and a kcat of 117.2 s−1, compared to lichenin which had a Km of 21.5 mg/mL and a kcat of 70.0 s−1. The circular dichroism profile of Exg-D showed that its secondary structure consisted of 11% α-helices, 36% β-strands and 53% coils. Exg-D performed transglycosylation using p-nitrophenyl cellobioside as a glycosyl donor and several primary alcohols as acceptors to produce methyl-, ethyl- and propyl-cellobiosides. These products were identified and quantified via thin-layer chromatography (TLC) and liquid chromatography–mass spectrometry (LC-MS). We concluded that Exg-D is a novel and promising oligomeric glycoside hydrolase for the one-step synthesis of alkyl glycosides with more than one monosaccharide unit.
- Full Text:
- Date Issued: 2020
- Authors: Mafa, Mpho S , Dirr, Heinrich W , Malgas, Samkelo , Krause, Rui W M , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193976 , vital:45412 , xlink:href="https://doi.org/10.3390/molecules25030746"
- Description: An exoglucanase (Exg-D) from the glycoside hydrolase family 5 subfamily 38 (GH5_38) was heterologously expressed and structurally and biochemically characterised at a molecular level for its application in alkyl glycoside synthesis. The purified Exg-D existed in both dimeric and monomeric forms in solution, which showed highest activity on mixed-linked β-glucan (88.0 and 86.7 U/mg protein, respectively) and lichenin (24.5 and 23.7 U/mg protein, respectively). They displayed a broad optimum pH range from 5.5 to 7 and a temperature optimum from 40 to 60 °C. Kinetic studies demonstrated that Exg-D had a higher affinity towards β-glucan, with a Km of 7.9 mg/mL and a kcat of 117.2 s−1, compared to lichenin which had a Km of 21.5 mg/mL and a kcat of 70.0 s−1. The circular dichroism profile of Exg-D showed that its secondary structure consisted of 11% α-helices, 36% β-strands and 53% coils. Exg-D performed transglycosylation using p-nitrophenyl cellobioside as a glycosyl donor and several primary alcohols as acceptors to produce methyl-, ethyl- and propyl-cellobiosides. These products were identified and quantified via thin-layer chromatography (TLC) and liquid chromatography–mass spectrometry (LC-MS). We concluded that Exg-D is a novel and promising oligomeric glycoside hydrolase for the one-step synthesis of alkyl glycosides with more than one monosaccharide unit.
- Full Text:
- Date Issued: 2020
A novel gold (I)-mediated intramolecular transamidation of benzoyl thiourea derivatives to form benzamides via dethiocyanation
- Odame, Felix, Woodcock, Guillaume, Hosten, Eric C, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Woodcock, Guillaume , Hosten, Eric C , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446988 , vital:74575 , xlink:href="https://doi.org/10.1016/j.jorganchem.2020.121359"
- Description: A novel gold(I)-mediated intramolecular transamidation of thiourea derivatives to yield benzamides via dethiocyanation have been achieved by the reaction of 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea derivatives in the presence of gold(I) precursors. The compounds have been characterized using IR, NMR, GC-MS and microanalysis. The single crystal XRD of 3-(1,3-benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (5), 3-(1,3-benzothiazol-2-yl)-1-(3-methoxybenzoyl)thiourea (6), N-(benzothiazol-2-yl)benzamide (10), N-(benzothiazol-2-yl)-3-chlorobenzamide (11), N-(benzothiazol-2-yl)-4-nitrobenzamide (12), N-(benzothiazol-2-yl)-3-bromobenzamide (14) have been discussed. The novel transformation is thought to proceed by a gold(I)-mediated intramolecular transamidation reaction which releases thiocyanate to yield the benzamide. Density functional theory calculations have been used to support the proposed mechanism for this transformation.
- Full Text:
- Date Issued: 2020
- Authors: Odame, Felix , Woodcock, Guillaume , Hosten, Eric C , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446988 , vital:74575 , xlink:href="https://doi.org/10.1016/j.jorganchem.2020.121359"
- Description: A novel gold(I)-mediated intramolecular transamidation of thiourea derivatives to yield benzamides via dethiocyanation have been achieved by the reaction of 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea derivatives in the presence of gold(I) precursors. The compounds have been characterized using IR, NMR, GC-MS and microanalysis. The single crystal XRD of 3-(1,3-benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (5), 3-(1,3-benzothiazol-2-yl)-1-(3-methoxybenzoyl)thiourea (6), N-(benzothiazol-2-yl)benzamide (10), N-(benzothiazol-2-yl)-3-chlorobenzamide (11), N-(benzothiazol-2-yl)-4-nitrobenzamide (12), N-(benzothiazol-2-yl)-3-bromobenzamide (14) have been discussed. The novel transformation is thought to proceed by a gold(I)-mediated intramolecular transamidation reaction which releases thiocyanate to yield the benzamide. Density functional theory calculations have been used to support the proposed mechanism for this transformation.
- Full Text:
- Date Issued: 2020
A novel, improved throughput bioassay for determining the delative speed of antimalarial drug action using fluorescent vitality probes
- Authors: Laming, Dustin
- Date: 2020
- Subjects: Plasmodium falciparum , Malaria -- Treatment -- Africa , Antimalarials , Malaria vaccine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/139902 , vital:37810
- Description: Malaria is one of the most prevalent diseases in Africa and Plasmodium falciparum is widely accepted as the most virulent of the malaria parasite species, with a fatality rate of 15 – 20 % of reported cases of infection. While various treatments have been accepted into early stage clinical trials, there has been little progress towards a proven vaccine. Pending a long-term solution, endemic countries rely heavily on the development of innovative drugs that are not only efficacious but are also quick acting. Traditional methods of evaluating antimalarial killing speeds via morphological assessments are inherently flawed by tedious, subjective interpretations of the heterogenous parasite morphology encountered in routine parasite culture conditions. This has led to the introduction of alternative assay formats to determine how rapidly compounds act on parasites in vitro: a parasite reduction ratio (PRR) assay that measures the recovery of parasite cultures from drug exposure; determining the shift in IC50 values of compounds when dose-response assays are carried out for different time periods; a bioluminescence relative rate of kill (BRRoK) assay that compares the extent to which compounds reduce firefly luciferase activity in transgenic parasites. Recent whole cell in vitro screening efforts have resulted in the generation of chemically diverse compound libraries such as the Medicines for Malaria Venture’s Pathogen Box, which houses 125 novel compounds with in vitro antiplasmodial activity. Assessing the relative killing speeds of these compounds would aid prioritizing fast-acting compounds that can be exploited as starting points for further development. This study aimed to develop a bioassay using the calcein-acetoxymethyl and propidium iodide fluorescent vitality probes, which would allow the relative speed of drug action on Plasmodium falciparum malaria parasites to be assessed and ranked in relation to each other using a quantitative, improved throughput approach. Initially applied to human (HeLa) cells, the assay was used to compare the relative speeds of action of 3 potential anti-cancer compounds by fluorescence microscopy. Subsequently adapted to P. falciparum, the assay was able to rank the relative speeds of action of standard antimalarials by fluorescence microscopy and two flow cytometry formats. Application of a multiwell flow cytometer increased throughput and enabled the assessment of experimental compounds, which included a set of artemisinin analogs and 125 antimalarial compounds in the MMV Pathogen Box. The latter culminated in the identification of five rapidly parasiticidal compounds in relation to the other compounds in the library, which may act as benchmark references for future studies and form the basis of the next generation of fast acting antimalarials that could be used to combat modern, resistant malaria.
- Full Text:
- Date Issued: 2020
- Authors: Laming, Dustin
- Date: 2020
- Subjects: Plasmodium falciparum , Malaria -- Treatment -- Africa , Antimalarials , Malaria vaccine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/139902 , vital:37810
- Description: Malaria is one of the most prevalent diseases in Africa and Plasmodium falciparum is widely accepted as the most virulent of the malaria parasite species, with a fatality rate of 15 – 20 % of reported cases of infection. While various treatments have been accepted into early stage clinical trials, there has been little progress towards a proven vaccine. Pending a long-term solution, endemic countries rely heavily on the development of innovative drugs that are not only efficacious but are also quick acting. Traditional methods of evaluating antimalarial killing speeds via morphological assessments are inherently flawed by tedious, subjective interpretations of the heterogenous parasite morphology encountered in routine parasite culture conditions. This has led to the introduction of alternative assay formats to determine how rapidly compounds act on parasites in vitro: a parasite reduction ratio (PRR) assay that measures the recovery of parasite cultures from drug exposure; determining the shift in IC50 values of compounds when dose-response assays are carried out for different time periods; a bioluminescence relative rate of kill (BRRoK) assay that compares the extent to which compounds reduce firefly luciferase activity in transgenic parasites. Recent whole cell in vitro screening efforts have resulted in the generation of chemically diverse compound libraries such as the Medicines for Malaria Venture’s Pathogen Box, which houses 125 novel compounds with in vitro antiplasmodial activity. Assessing the relative killing speeds of these compounds would aid prioritizing fast-acting compounds that can be exploited as starting points for further development. This study aimed to develop a bioassay using the calcein-acetoxymethyl and propidium iodide fluorescent vitality probes, which would allow the relative speed of drug action on Plasmodium falciparum malaria parasites to be assessed and ranked in relation to each other using a quantitative, improved throughput approach. Initially applied to human (HeLa) cells, the assay was used to compare the relative speeds of action of 3 potential anti-cancer compounds by fluorescence microscopy. Subsequently adapted to P. falciparum, the assay was able to rank the relative speeds of action of standard antimalarials by fluorescence microscopy and two flow cytometry formats. Application of a multiwell flow cytometer increased throughput and enabled the assessment of experimental compounds, which included a set of artemisinin analogs and 125 antimalarial compounds in the MMV Pathogen Box. The latter culminated in the identification of five rapidly parasiticidal compounds in relation to the other compounds in the library, which may act as benchmark references for future studies and form the basis of the next generation of fast acting antimalarials that could be used to combat modern, resistant malaria.
- Full Text:
- Date Issued: 2020
A personality-based surveillance model for Facebook apps
- Authors: Van der Schyff, Karl Izak
- Date: 2020
- Subjects: Facebook (Electronic resource) , Electronic surveillance -- Psychological aspects , Online social networks -- Psychological aspects , Social media -- Psychological aspects , Personality
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145534 , vital:38447
- Description: The surveillance of data through the use of Facebook Apps is an ongoing and persistent problem that impacts millions of users. Nonetheless, limited research has been conducted investigating to what extent a Facebook user’s personality influences their awareness of such surveillance practices. Thus, to understand this situation better, the current study inductively developed four propositions from secondary data sources as part of a detailed content analysis. Spanning three search and analysis phases the content analysis led to the development of the research model. Guided by the propositions and research questions, a questionnaire was developed based on the relevant constructs prescribed by the Theory of Planned Behaviour. This questionnaire was used, and a total of 651 responses were collected from Facebook users over the age of 18 years old and residing in the United States of America. Primary data took place at both a univariate and multivariate level with a specific focus on the development of a structural model. Interpretation of the structural model revealed that out of all the Big Five personality traits, Conscientiousness exhibited the strongest relationship with information security awareness followed by Openness to Experience and Neuroticism, respectively. The results further indicated that the model constructs based on attitude, social norms and awareness significantly influenced the intended use of Facebook Apps. The study also contributes by indicating which personality traits are most vulnerable to Facebook App surveillance. For example, it was found that individuals high in Conscientiousness are the least vulnerable with individuals high in Extraversion being the most vulnerable. Since the results indicate that not all the personality traits are significantly related to the model constructs, additional factors may contribute to App surveillance in this context. Concerning this, factors such as user apathy, information privacy, privacy concerns, control and Facebook dependency are discussed as a means to argue why this might be the case.
- Full Text:
- Date Issued: 2020
- Authors: Van der Schyff, Karl Izak
- Date: 2020
- Subjects: Facebook (Electronic resource) , Electronic surveillance -- Psychological aspects , Online social networks -- Psychological aspects , Social media -- Psychological aspects , Personality
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145534 , vital:38447
- Description: The surveillance of data through the use of Facebook Apps is an ongoing and persistent problem that impacts millions of users. Nonetheless, limited research has been conducted investigating to what extent a Facebook user’s personality influences their awareness of such surveillance practices. Thus, to understand this situation better, the current study inductively developed four propositions from secondary data sources as part of a detailed content analysis. Spanning three search and analysis phases the content analysis led to the development of the research model. Guided by the propositions and research questions, a questionnaire was developed based on the relevant constructs prescribed by the Theory of Planned Behaviour. This questionnaire was used, and a total of 651 responses were collected from Facebook users over the age of 18 years old and residing in the United States of America. Primary data took place at both a univariate and multivariate level with a specific focus on the development of a structural model. Interpretation of the structural model revealed that out of all the Big Five personality traits, Conscientiousness exhibited the strongest relationship with information security awareness followed by Openness to Experience and Neuroticism, respectively. The results further indicated that the model constructs based on attitude, social norms and awareness significantly influenced the intended use of Facebook Apps. The study also contributes by indicating which personality traits are most vulnerable to Facebook App surveillance. For example, it was found that individuals high in Conscientiousness are the least vulnerable with individuals high in Extraversion being the most vulnerable. Since the results indicate that not all the personality traits are significantly related to the model constructs, additional factors may contribute to App surveillance in this context. Concerning this, factors such as user apathy, information privacy, privacy concerns, control and Facebook dependency are discussed as a means to argue why this might be the case.
- Full Text:
- Date Issued: 2020
A psychobiographical case study: Amelia Dyer in a search for glory
- Authors: April, Heather
- Date: 2020
- Subjects: Serial murderers--Psychology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50857 , vital:43008
- Description: The study is a psychobiographical case study based on the life of a Victorian baby farmer Amelia Dyer (1837-1896). She was executed for the murder of babies who were placed in her care over a period of 30 years. Psychobiography is a qualitative method of enquiry which explores the life of a unique individual subject through the lens of a psychological theory for the purpose of creating a coherent psychological case study. The psychoanalytic theoretical lens of Karen Horney was used to trace the evolution of Amelia Dyer’s sense of self within the Victorian culture of respectability. Baby farming referred to an unregulated business of adoption and fostering of infants, mostly illegitimate infants for a fee. Insufficient social structures and support for unwed mothers and children encouraged the business practice as women had very little choice for childcare. Baby farming was open to abuse and exploitation and hundreds of babies lost their lives due to insufficient care or infanticide. Amelia Dyer showed special talents and creativity from a young age, was ambitious and wanted to be self-reliant in a culture that did not provide women with opportunities to live out their ambitions. Baby farming became a business venture for her in the early stages of her life which later evolved into sadistic abuse and murder of the infants. Her evolution from a creative and hardworking young girl to a sadistic murderer of children is what qualifies her as a suitable subject for the exploration of Karen Horney’s dynamic theory of neuroses and the development of the neurotic self within culture. Extensive biographical data was collected and processed into salient themes. The study integrates the theory of Karen Horney, the life experiences of Amelia Dyer and Victorian respectability and demonstrates the value of using psychobiography as the method of inquiry into the exploration of the unique individual. The findings of the study demonstrated that Amelia Dyer and her social context were inextricably bound by a vicious cycle of psychic and emotional vi conflicts related to fear, control and self-hatred by the internalization of gender stereotypes and norms. The contribution of the study as a whole rests with its demonstration of the value of a holistic and reflexive exploration of the unique individual woman. It demonstrates the value of Horney’s in-depth theoretical understanding of the ambivalent core of selfhood that lies behind observable acts of behavior. The study as a whole contributes towards building upon holistic and integrative therapeutic frameworks in the understanding of diversity amongst women and mothers in culture.
- Full Text:
- Date Issued: 2020
- Authors: April, Heather
- Date: 2020
- Subjects: Serial murderers--Psychology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50857 , vital:43008
- Description: The study is a psychobiographical case study based on the life of a Victorian baby farmer Amelia Dyer (1837-1896). She was executed for the murder of babies who were placed in her care over a period of 30 years. Psychobiography is a qualitative method of enquiry which explores the life of a unique individual subject through the lens of a psychological theory for the purpose of creating a coherent psychological case study. The psychoanalytic theoretical lens of Karen Horney was used to trace the evolution of Amelia Dyer’s sense of self within the Victorian culture of respectability. Baby farming referred to an unregulated business of adoption and fostering of infants, mostly illegitimate infants for a fee. Insufficient social structures and support for unwed mothers and children encouraged the business practice as women had very little choice for childcare. Baby farming was open to abuse and exploitation and hundreds of babies lost their lives due to insufficient care or infanticide. Amelia Dyer showed special talents and creativity from a young age, was ambitious and wanted to be self-reliant in a culture that did not provide women with opportunities to live out their ambitions. Baby farming became a business venture for her in the early stages of her life which later evolved into sadistic abuse and murder of the infants. Her evolution from a creative and hardworking young girl to a sadistic murderer of children is what qualifies her as a suitable subject for the exploration of Karen Horney’s dynamic theory of neuroses and the development of the neurotic self within culture. Extensive biographical data was collected and processed into salient themes. The study integrates the theory of Karen Horney, the life experiences of Amelia Dyer and Victorian respectability and demonstrates the value of using psychobiography as the method of inquiry into the exploration of the unique individual. The findings of the study demonstrated that Amelia Dyer and her social context were inextricably bound by a vicious cycle of psychic and emotional vi conflicts related to fear, control and self-hatred by the internalization of gender stereotypes and norms. The contribution of the study as a whole rests with its demonstration of the value of a holistic and reflexive exploration of the unique individual woman. It demonstrates the value of Horney’s in-depth theoretical understanding of the ambivalent core of selfhood that lies behind observable acts of behavior. The study as a whole contributes towards building upon holistic and integrative therapeutic frameworks in the understanding of diversity amongst women and mothers in culture.
- Full Text:
- Date Issued: 2020
A psychobiographical study of Maya Angelo
- Authors: De Waal, Leandra
- Date: 2020
- Subjects: Angelou, Maya
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46341 , vital:39569
- Description: Psychobiographies aim to gain a deeper understanding into the lives of notable or notorious individuals through the lens of a psychological theory. Thisstudy aimedto gain insight into the personality development of Maya Angelou through the useof Erikson’s Theory of PsychosocialDevelopment. The study exploresand describesher life experiences in terms of this theory, and understandsher life within her socio-historical context. Angelou is a renowned literary figure. Herjourney to becoming a writer was an arduous one, marked by great hardships from an early age. Despite early parental abandonment, childhood rape, exposure to racism, and difficulties in romantic relationships, she developed into a healthy adult who achieved much literary success and inspired individuals worldwide.Nonprobability purposive sampling was used to selectAngelou as the subjectand was madeon the basis of the researcher’s interest in Angelou’s life history.Datawas collected by triangulating multiple sources of informationand analysed using the approach developed by Miles and Huberman, which involves threesteps: data reduction, data display, and conclusion drawing and verification.The main findings suggest that Angelou progressed through Erikson’s eight stages successfully, despite some delays in negotiations of crises.
- Full Text:
- Date Issued: 2020
- Authors: De Waal, Leandra
- Date: 2020
- Subjects: Angelou, Maya
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46341 , vital:39569
- Description: Psychobiographies aim to gain a deeper understanding into the lives of notable or notorious individuals through the lens of a psychological theory. Thisstudy aimedto gain insight into the personality development of Maya Angelou through the useof Erikson’s Theory of PsychosocialDevelopment. The study exploresand describesher life experiences in terms of this theory, and understandsher life within her socio-historical context. Angelou is a renowned literary figure. Herjourney to becoming a writer was an arduous one, marked by great hardships from an early age. Despite early parental abandonment, childhood rape, exposure to racism, and difficulties in romantic relationships, she developed into a healthy adult who achieved much literary success and inspired individuals worldwide.Nonprobability purposive sampling was used to selectAngelou as the subjectand was madeon the basis of the researcher’s interest in Angelou’s life history.Datawas collected by triangulating multiple sources of informationand analysed using the approach developed by Miles and Huberman, which involves threesteps: data reduction, data display, and conclusion drawing and verification.The main findings suggest that Angelou progressed through Erikson’s eight stages successfully, despite some delays in negotiations of crises.
- Full Text:
- Date Issued: 2020