Challenges facing Ubomi Obutsha gardening project in kwazakhele, Port elizabeth
- Authors: Malangeni, Silindile Portia
- Date: 2018
- Subjects: Community development -- South Africa -- Port Elizabeth , Economic development projects -- South Africa -- Port Elizabeth Poverty -- Economic aspects -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22453 , vital:29971
- Description: Food gardening projects are mostly grappling with access to seeds, water and suitable equipment in developing communities. Such projects are a direct and effective way to enhance food availability and access and strengthen the resilience of local food systems. This study has investigated the challenges facing food gardening project in KwaZakhele Township, Port Elizabeth. The study followed qualitative approach which include individual interviews using an interview schedule. To supplement the interviews, secondary data was gathered from relevant journals, books and other sources. The research objectives of this study include among others, to investigate the challenges experienced by the members of Ubomi Obutsha gardening project in KwaZakhele Township, to contribute within the body of knowledge in poverty alleviation discourse and to come up with the recommendations with the view to resolve some of the problems pertaining to Ubomi Obutsha gardening project in KwaZakhele Township.
- Full Text:
- Date Issued: 2018
- Authors: Malangeni, Silindile Portia
- Date: 2018
- Subjects: Community development -- South Africa -- Port Elizabeth , Economic development projects -- South Africa -- Port Elizabeth Poverty -- Economic aspects -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22453 , vital:29971
- Description: Food gardening projects are mostly grappling with access to seeds, water and suitable equipment in developing communities. Such projects are a direct and effective way to enhance food availability and access and strengthen the resilience of local food systems. This study has investigated the challenges facing food gardening project in KwaZakhele Township, Port Elizabeth. The study followed qualitative approach which include individual interviews using an interview schedule. To supplement the interviews, secondary data was gathered from relevant journals, books and other sources. The research objectives of this study include among others, to investigate the challenges experienced by the members of Ubomi Obutsha gardening project in KwaZakhele Township, to contribute within the body of knowledge in poverty alleviation discourse and to come up with the recommendations with the view to resolve some of the problems pertaining to Ubomi Obutsha gardening project in KwaZakhele Township.
- Full Text:
- Date Issued: 2018
Challenging Biblical boundaries: Jeanette Winterson’s postmodern feminist subversion of Biblical discourse in Oranges are not the only fruit (1985) and Boating for beginners (1985)
- Authors: Erasmus, Shirley
- Date: 2018
- Subjects: Winterson, Jeanette, 1959- -- Criticism and interpretation , Bible -- Feminist criticism , Bible -- Criticism, interpretation, etc , Postmodernism -- Religious aspects , Winterson, Jeanette, 1959- -- Oranges are not the only fruit , Winterson, Jeanette, 1959- -- Boating for beginners , Patriarchy in literature , Sex discrimination in literature
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/59121 , vital:27430
- Description: This thesis investigates the subversion of Biblical discourse in Jeanette Winterson’s first two novels, Oranges are Not the Only Fruit and Boating for Beginners. By rewriting Biblical stories Winterson challenges traditional Western religious discourses and their rules for heteronormative social and sexual behaviours and desires. Winterson’s texts respond to the patriarchal nature of socially pervasive texts, such as the Bible, by encouraging her readers to regard these texts with suspicion, thus highlighting what can be seen as a ‘postmodern concern’ with the notion of ‘truth’. Chapter One of this thesis comprises a discussion of Biblical boundaries. These boundaries, I argue, are a process of historical oppression which serves to subjugate and control women, a practice inherent in the Bible and modern society. The Biblical boundaries within which women are expected to live, are carefully portrayed in Oranges and then comically and blasphemously mocked in Boating. Chapter One also argues that Winterson’s sexuality plays an important role in the understanding of her texts, despite her desire for her sexuality to remain ‘outside’ her writing. Chapter Two of this thesis, examines the mix of fact and fiction in Oranges, in order to create a new genre: fictional memoir. The chapter introduces the concept of the ‘autobiographical pact’ and the textual agreement which Winterson creates with her readers. In this chapter, I examine Winterson’s powerful subversion of Biblical discourse, through her narration of Jeanette’s ‘coming out’ within a Biblical framework. Chapter Three of this thesis examines Winterson’s second book, Boating, and the serious elements of this comic book. This chapter studies the various postmodern narrative techniques used in Boating in order to subvert Biblical and historical discourse. Chapter Three highlights Winterson’s postmodern concern with the construction of history as ‘truth’. Finally, Chapter Four compares Oranges and Boating, showing the texts as differing, yet equally relevant textual counterparts. This chapter examines the anti-feminine characters in both texts and Winterson’s ability to align her reader with a feminist or lesbian viewpoint. This thesis argues that Winterson’s first two texts deliberately challenge Biblical discourse in favour of a postmodern feminist viewpoint.
- Full Text:
- Date Issued: 2018
- Authors: Erasmus, Shirley
- Date: 2018
- Subjects: Winterson, Jeanette, 1959- -- Criticism and interpretation , Bible -- Feminist criticism , Bible -- Criticism, interpretation, etc , Postmodernism -- Religious aspects , Winterson, Jeanette, 1959- -- Oranges are not the only fruit , Winterson, Jeanette, 1959- -- Boating for beginners , Patriarchy in literature , Sex discrimination in literature
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/59121 , vital:27430
- Description: This thesis investigates the subversion of Biblical discourse in Jeanette Winterson’s first two novels, Oranges are Not the Only Fruit and Boating for Beginners. By rewriting Biblical stories Winterson challenges traditional Western religious discourses and their rules for heteronormative social and sexual behaviours and desires. Winterson’s texts respond to the patriarchal nature of socially pervasive texts, such as the Bible, by encouraging her readers to regard these texts with suspicion, thus highlighting what can be seen as a ‘postmodern concern’ with the notion of ‘truth’. Chapter One of this thesis comprises a discussion of Biblical boundaries. These boundaries, I argue, are a process of historical oppression which serves to subjugate and control women, a practice inherent in the Bible and modern society. The Biblical boundaries within which women are expected to live, are carefully portrayed in Oranges and then comically and blasphemously mocked in Boating. Chapter One also argues that Winterson’s sexuality plays an important role in the understanding of her texts, despite her desire for her sexuality to remain ‘outside’ her writing. Chapter Two of this thesis, examines the mix of fact and fiction in Oranges, in order to create a new genre: fictional memoir. The chapter introduces the concept of the ‘autobiographical pact’ and the textual agreement which Winterson creates with her readers. In this chapter, I examine Winterson’s powerful subversion of Biblical discourse, through her narration of Jeanette’s ‘coming out’ within a Biblical framework. Chapter Three of this thesis examines Winterson’s second book, Boating, and the serious elements of this comic book. This chapter studies the various postmodern narrative techniques used in Boating in order to subvert Biblical and historical discourse. Chapter Three highlights Winterson’s postmodern concern with the construction of history as ‘truth’. Finally, Chapter Four compares Oranges and Boating, showing the texts as differing, yet equally relevant textual counterparts. This chapter examines the anti-feminine characters in both texts and Winterson’s ability to align her reader with a feminist or lesbian viewpoint. This thesis argues that Winterson’s first two texts deliberately challenge Biblical discourse in favour of a postmodern feminist viewpoint.
- Full Text:
- Date Issued: 2018
Characterisation of surfaces modified with phthalocyanines through click chemistry for applications in electrochemical sensing
- O'Donoghue, Charles St John Nqwabuko
- Authors: O'Donoghue, Charles St John Nqwabuko
- Date: 2018
- Subjects: Electrodes, Carbon , Phthalocyanines , X-ray photoelectron spectroscopy , Electrochemistry , Electrochemical sensors , Hydrazine , Click chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58046 , vital:27038
- Description: One form of surface modification was primarily investigated in this work on glassy carbon electrodes. The form of modification is comprised of a series of steps in which electrografting is first applied to the glassy carbon surface, which is then followed up with click chemistry to ultimately immobilise a phthalocyanine onto the surface. The modified glassy carbon electrodes and surfaces were characterised with a combination of scanning electrochemical microscopy, X-ray photoelectron spectroscopy and various electrochemical methods. In this work, three alkyne substituted phthalocyanines were used. Two novel phthalocyanines, with nickel and cobalt metal centres, were studied alongside a manganese phthalocyanine reported in literature. Each of the three phthalocyanines was modified at the peripheral position with a 1-hexyne group, via a glycosidic bond, yielding the terminal alkyne groups that were used for subsequent click reactions. In situ diazotisation was used to graft 4-azidoaniline groups to the surface of the glassy carbon electrode. The azide bearing 4- azidoaniline groups were thus used to anchor the tetra substituted phthalocyanines to the surface of the electrodes. This method yielded successful modification of the electrodes and lead to their application in sensing studies. The modified electrodes were primarily used to catalyse the common agricultural oxidising agent hydrazine.
- Full Text:
- Date Issued: 2018
- Authors: O'Donoghue, Charles St John Nqwabuko
- Date: 2018
- Subjects: Electrodes, Carbon , Phthalocyanines , X-ray photoelectron spectroscopy , Electrochemistry , Electrochemical sensors , Hydrazine , Click chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58046 , vital:27038
- Description: One form of surface modification was primarily investigated in this work on glassy carbon electrodes. The form of modification is comprised of a series of steps in which electrografting is first applied to the glassy carbon surface, which is then followed up with click chemistry to ultimately immobilise a phthalocyanine onto the surface. The modified glassy carbon electrodes and surfaces were characterised with a combination of scanning electrochemical microscopy, X-ray photoelectron spectroscopy and various electrochemical methods. In this work, three alkyne substituted phthalocyanines were used. Two novel phthalocyanines, with nickel and cobalt metal centres, were studied alongside a manganese phthalocyanine reported in literature. Each of the three phthalocyanines was modified at the peripheral position with a 1-hexyne group, via a glycosidic bond, yielding the terminal alkyne groups that were used for subsequent click reactions. In situ diazotisation was used to graft 4-azidoaniline groups to the surface of the glassy carbon electrode. The azide bearing 4- azidoaniline groups were thus used to anchor the tetra substituted phthalocyanines to the surface of the electrodes. This method yielded successful modification of the electrodes and lead to their application in sensing studies. The modified electrodes were primarily used to catalyse the common agricultural oxidising agent hydrazine.
- Full Text:
- Date Issued: 2018
Characteristics and key-success factors of future sought-after retirement villages in George, South Africa
- Authors: Earle, Isak Sameul
- Date: 2018
- Subjects: Retirement communities -- South Africa -- George , Retirees -- Housing -- South Africa -- George Retirement -- South Africa -- George -- Planning Retirees -- South Africa -- George -- Economic conditions
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22038 , vital:29815
- Description: This study is about obtaining information about international and national trends and features of sought-after retirement villages by means of a literature review (secondary research) as well as by means of a survey amongst estate agents and retirees currently residing in George (primary research). The primary research objective was to develop a Retirement Village Features Model (a set of features, development guidelines, conditions and requirements) for a sought-after retirement village in George, derived from scientific knowledge, resultant from findings and conclusions from primary and secondary research conducted by the researcher. The literature review revealed that worldwide, the population continues to get older and that the number of retirees requiring retirement homes is growing and supply is not keeping pace with the ever-growing demand. It also revealed 16 characteristics of retirement villages that were used as a basis for designing the questionnaire namely the expectation and the importance of: living amongst peers for social interaction, safety and security facilities, an easy-care lifestyle, economic investment security, recreational leisure facilities, beautiful designed buildings and homes, location, privacy, effective management of the development, well nurtured gardens, paved pedestrian walkways, wheelchair friendly designs, low maintenance housing designs, offering facilities for successful ageing, green energy design houses and facilities and the importance of not selling to potential buyers under the age of 50. Although the expectation of each of the 16 characteristics of a sought-after retirement village was high for most participants, the level of importance of each characteristic varied quite a lot. This might be a good indication that participants would like to have all the characteristics present in the development but are sceptical about costs that might be incurred to the homeowner having those characteristics present in the village. The participants in the study also indicated various desired characteristics of a future sought after retirement village that forms part of the Model which conforms to literature findings. These include: emergency assistance button in houses and emergency response services, a clubhouse with catering and braai facilities, WI-FI services in all areas, a pet-friendly environment with park for domestic animals and access to Frail Care and Assisted Living facilities. Participants in the survey also indicated their preference for housing in future sought-after retirement villages namely; 52.17% preferred a two bedroom privately owned home, 33.04% preferred a three bedroom privately owned house, 7.83% preferred renting a one or two-bedroom house and 6.96% prefer a one bedroom privately owned house. 71.31% of participants who responded regarded assisted living services and frail care services and facilities as very important or of utmost importance. This paper was aimed at capturing the essence of how retirees feel about their homes and lifestyle environments. By incorporating the findings and recommendations contained in this study into their development plans for future retirement villages, development companies will have a competitive advantage over their rivals in this industry. It is recommended that future research regarding retirement villages should include other regions in South Africa to improve the model. It is also recommended that further research can be done on how expected facilities in retirement villages can become self- sufficient and subsequently alleviating the maintenance costs for homeowners and hence rendering more value to the homeowner.
- Full Text:
- Date Issued: 2018
- Authors: Earle, Isak Sameul
- Date: 2018
- Subjects: Retirement communities -- South Africa -- George , Retirees -- Housing -- South Africa -- George Retirement -- South Africa -- George -- Planning Retirees -- South Africa -- George -- Economic conditions
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22038 , vital:29815
- Description: This study is about obtaining information about international and national trends and features of sought-after retirement villages by means of a literature review (secondary research) as well as by means of a survey amongst estate agents and retirees currently residing in George (primary research). The primary research objective was to develop a Retirement Village Features Model (a set of features, development guidelines, conditions and requirements) for a sought-after retirement village in George, derived from scientific knowledge, resultant from findings and conclusions from primary and secondary research conducted by the researcher. The literature review revealed that worldwide, the population continues to get older and that the number of retirees requiring retirement homes is growing and supply is not keeping pace with the ever-growing demand. It also revealed 16 characteristics of retirement villages that were used as a basis for designing the questionnaire namely the expectation and the importance of: living amongst peers for social interaction, safety and security facilities, an easy-care lifestyle, economic investment security, recreational leisure facilities, beautiful designed buildings and homes, location, privacy, effective management of the development, well nurtured gardens, paved pedestrian walkways, wheelchair friendly designs, low maintenance housing designs, offering facilities for successful ageing, green energy design houses and facilities and the importance of not selling to potential buyers under the age of 50. Although the expectation of each of the 16 characteristics of a sought-after retirement village was high for most participants, the level of importance of each characteristic varied quite a lot. This might be a good indication that participants would like to have all the characteristics present in the development but are sceptical about costs that might be incurred to the homeowner having those characteristics present in the village. The participants in the study also indicated various desired characteristics of a future sought after retirement village that forms part of the Model which conforms to literature findings. These include: emergency assistance button in houses and emergency response services, a clubhouse with catering and braai facilities, WI-FI services in all areas, a pet-friendly environment with park for domestic animals and access to Frail Care and Assisted Living facilities. Participants in the survey also indicated their preference for housing in future sought-after retirement villages namely; 52.17% preferred a two bedroom privately owned home, 33.04% preferred a three bedroom privately owned house, 7.83% preferred renting a one or two-bedroom house and 6.96% prefer a one bedroom privately owned house. 71.31% of participants who responded regarded assisted living services and frail care services and facilities as very important or of utmost importance. This paper was aimed at capturing the essence of how retirees feel about their homes and lifestyle environments. By incorporating the findings and recommendations contained in this study into their development plans for future retirement villages, development companies will have a competitive advantage over their rivals in this industry. It is recommended that future research regarding retirement villages should include other regions in South Africa to improve the model. It is also recommended that further research can be done on how expected facilities in retirement villages can become self- sufficient and subsequently alleviating the maintenance costs for homeowners and hence rendering more value to the homeowner.
- Full Text:
- Date Issued: 2018
Characteristics of the thermoluminescence of Sm3+-doped P2O5-K2O-MgO-Al2O3-ZnF2 glass
- Thomas, Sunil, Chithambo, Makaiko L
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/109979 , vital:33211 , https://doi.org/10.1016/j.radmeas.2018.06.005
- Description: We report the thermoluminescence of Sm3+-doped P2O5-K2O-MgO-Al2O3-ZnF2 glass. A glow-curve measured at 1 °C/s after beta irradiation to 10 Gy shows two peaks; a broad high intensity one at 214.0 ± 0.4 °C and a weaker intensity peak at 75.2 ± 0.8 °C. The dependence of peak position on partial heating as well as on irradiation suggest that the main peak at 214 °C is a combination of several overlapping peaks. The activation energy of the different components of the main peak, calculated using the initial-rise method, differ showing that the components are distinct. The reproducibility, fading and dose response were examined by considering the dominant component of the main peak. The intensity of the peak changes with heating rate in a manner consistent with thermal quenching.
- Full Text: false
- Date Issued: 2018
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/109979 , vital:33211 , https://doi.org/10.1016/j.radmeas.2018.06.005
- Description: We report the thermoluminescence of Sm3+-doped P2O5-K2O-MgO-Al2O3-ZnF2 glass. A glow-curve measured at 1 °C/s after beta irradiation to 10 Gy shows two peaks; a broad high intensity one at 214.0 ± 0.4 °C and a weaker intensity peak at 75.2 ± 0.8 °C. The dependence of peak position on partial heating as well as on irradiation suggest that the main peak at 214 °C is a combination of several overlapping peaks. The activation energy of the different components of the main peak, calculated using the initial-rise method, differ showing that the components are distinct. The reproducibility, fading and dose response were examined by considering the dominant component of the main peak. The intensity of the peak changes with heating rate in a manner consistent with thermal quenching.
- Full Text: false
- Date Issued: 2018
Characterization and computational studies of a co-crystal of 2-aminobenzimidazole and 2-[(benzoylcarbamothioyl) amino] propanoic acid
- Odame, Felix, Hosten, Eric C, Betz, Richard, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447030 , vital:74578 , xlink:href="https://doi.org/10.1134/S0022476618050268"
- Description: A novel co-crystal of 2-aminobenzimidazole and 2-[(benzoylcarbamothioyl)amino] propanoic acid is synthesized and characterized by spectroscopy, elemental analysis, GC-MS, and single crystal XRD. A computation of the structures involved in the formation of the co-crystal are carried out and their contribution to reactivity is explained.
- Full Text:
- Date Issued: 2018
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447030 , vital:74578 , xlink:href="https://doi.org/10.1134/S0022476618050268"
- Description: A novel co-crystal of 2-aminobenzimidazole and 2-[(benzoylcarbamothioyl)amino] propanoic acid is synthesized and characterized by spectroscopy, elemental analysis, GC-MS, and single crystal XRD. A computation of the structures involved in the formation of the co-crystal are carried out and their contribution to reactivity is explained.
- Full Text:
- Date Issued: 2018
Characterization and ecology of selected micro-estuaries and micro-outlets in the Eastern Cape province, South Africa
- Authors: Magoro, Mandla Leon
- Date: 2018
- Subjects: Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- Management Estuaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31644 , vital:31640
- Description: South Africa has more than 200 Temporarily Open/Closed Estuaries (TOCEs) along its approximately 3000 km coastline. In addition, there are approximately 200 micro-estuaries and micro-outlets on the subcontinent, many of which share some of the characteristics with TOCEs but differ in that they are supplied by localised coastal stream catchments with a more limited supply of freshwater and less connectivity to the marine environment. Between 2015 and 2016, this study endeavoured to investigate the physico-chemical properties, microalgal dynamics as well as the seasonal species abundance and composition of aquatic invertebrates and fishes in four micro-estuaries and four micro-outlets along the warm-temperate section of the Eastern Cape coast. The micro-outlets were dominated by oligohaline or freshwater conditions, while the micro-estuaries were mostly mesohaline. Microalgal biomass in these systems was influenced by temperature, nutrient conditions and light availability. Chironomidae and Ephemeroptera dominated benthic macro-invertebrate communities in the micro-outlets, while Amphipoda and Mysida were most dominant in micro-estuaries. Copepoda and Amphipoda dominated the zooplankton assemblages in both system types. Nekton communities in micro-outlets were dominated by juvenile Myxus capensis and tadpoles (mostly Xenopus laevis), while Oreochromis mossambicus, Gilchristella aestuaria, M. capensis and Mugil cephalus were the four most common species in the micro-estuaries. Seasonal variations in physico-chemical parameters and community composition of both the nekton and invertebrates were recorded during this study. Micro-estuaries and micro-outlets exhibited relatively lower diversity and abundances of biota than TOCEs. Furthermore, the micro-estuaries have a low estuarine function when compared to TOCEs, while the micro-outlets have very limited estuarine characteristics and were dominated by freshwater biota. The micro-systems are smaller in size and contain lower proportions of estuary-associated taxa when compared to larger estuarine systems such as TOCEs and permanently open estuaries. The results of this study confirm that there are distinctions between the biota of iv the two micro-system types, thus making biotic assemblages, together with physico-chemical parameters, a viable tool for differentiating between micro-estuaries and micro-outlets. This study represents the first investigation into the ecological functioning of micro-estuaries and micro-outlets. As a whole, micro-systems serve as nursery areas for freshwater-associated invertebrate taxa. Due to their limited periods of stability, micro-estuaries serve as intermediate nursery areas for 0+ juveniles of estuary-associated marine fish which, after less than a year, then migrate to larger estuarine systems located nearby. The small catchment size and short period of stability in these systems heightens their level of sensitivity to water flow alterations through dams, direct water abstraction, afforestation and watercourse diversion, while their lower buffering capacity makes them more susceptible to pollution and nutrient inputs from intensive agricultural activities and urban expansion.
- Full Text:
- Date Issued: 2018
- Authors: Magoro, Mandla Leon
- Date: 2018
- Subjects: Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- Management Estuaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31644 , vital:31640
- Description: South Africa has more than 200 Temporarily Open/Closed Estuaries (TOCEs) along its approximately 3000 km coastline. In addition, there are approximately 200 micro-estuaries and micro-outlets on the subcontinent, many of which share some of the characteristics with TOCEs but differ in that they are supplied by localised coastal stream catchments with a more limited supply of freshwater and less connectivity to the marine environment. Between 2015 and 2016, this study endeavoured to investigate the physico-chemical properties, microalgal dynamics as well as the seasonal species abundance and composition of aquatic invertebrates and fishes in four micro-estuaries and four micro-outlets along the warm-temperate section of the Eastern Cape coast. The micro-outlets were dominated by oligohaline or freshwater conditions, while the micro-estuaries were mostly mesohaline. Microalgal biomass in these systems was influenced by temperature, nutrient conditions and light availability. Chironomidae and Ephemeroptera dominated benthic macro-invertebrate communities in the micro-outlets, while Amphipoda and Mysida were most dominant in micro-estuaries. Copepoda and Amphipoda dominated the zooplankton assemblages in both system types. Nekton communities in micro-outlets were dominated by juvenile Myxus capensis and tadpoles (mostly Xenopus laevis), while Oreochromis mossambicus, Gilchristella aestuaria, M. capensis and Mugil cephalus were the four most common species in the micro-estuaries. Seasonal variations in physico-chemical parameters and community composition of both the nekton and invertebrates were recorded during this study. Micro-estuaries and micro-outlets exhibited relatively lower diversity and abundances of biota than TOCEs. Furthermore, the micro-estuaries have a low estuarine function when compared to TOCEs, while the micro-outlets have very limited estuarine characteristics and were dominated by freshwater biota. The micro-systems are smaller in size and contain lower proportions of estuary-associated taxa when compared to larger estuarine systems such as TOCEs and permanently open estuaries. The results of this study confirm that there are distinctions between the biota of iv the two micro-system types, thus making biotic assemblages, together with physico-chemical parameters, a viable tool for differentiating between micro-estuaries and micro-outlets. This study represents the first investigation into the ecological functioning of micro-estuaries and micro-outlets. As a whole, micro-systems serve as nursery areas for freshwater-associated invertebrate taxa. Due to their limited periods of stability, micro-estuaries serve as intermediate nursery areas for 0+ juveniles of estuary-associated marine fish which, after less than a year, then migrate to larger estuarine systems located nearby. The small catchment size and short period of stability in these systems heightens their level of sensitivity to water flow alterations through dams, direct water abstraction, afforestation and watercourse diversion, while their lower buffering capacity makes them more susceptible to pollution and nutrient inputs from intensive agricultural activities and urban expansion.
- Full Text:
- Date Issued: 2018
Characterization of residual stress driven deformation in terms of build height for thin walled laser metal deposition (Ti6AI4V) components
- Authors: Swan, Lindsay Jane
- Date: 2018
- Subjects: Titanium alloys Pulsed laser deposition
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/23537 , vital:30577
- Description: Ti6Al4V is the most commonly used of the titanium alloys and is known for its high strength to weight ratio and superb corrosion resistance compared to conventional steels. Ti6Al4V is used in applications in the aerospace, biomedical, automotive, power generation and oil and gas fields. Laser metal deposition (LMD) is an additive manufacturing (AM) platform used to build 3-D metal shapes. LMD is one of the most researched topics within the laser processing field currently and is advancing continuously. The rapid growth in the AM field is driven by market demands to reduce manufacturing costs, shorter lead times and an increasing demand for customized products. One of the major challenges facing the production of Ti6Al4V components using LMD is the high resultant residual stresses, limiting build size due to delamination or distortion. At the commencement of this study, little data pertaining to the residual stress build up in larger LMD components was available. This research was conducted to create an understanding of the relationship between build height and surface residual stresses and how they influence the dimensional stability of a part. Additionally, the relationship between build height and static mechanical properties was analysed. The effects of laser power, scanning speed and powder mass flow rate on the deposition layer were evaluated. The number of defects and the deposition build height were evaluated to determine the optimum process parameters for multi-layer components. An increase in laser power resulted in an increase in build height for the parameter window selected for the study. Similarly, an increase in build height was observed with an increase in powder mass flow rate, while an increase in scanning speed resulted in a decrease in build height. As laser power and scanning speed had inverse effects on the build height, heat input was evaluated to determine the optimum combination of the 2 parameters. Multilayer samples were produced with a laser power setting of 1900 W, a scanning speed of 0.01 m/s and a powder mass flow rate of 8 g/min. Fully dense components were produced with no notable defects. These components were analysed to reveal the relationship between build height and surface residual stresses and showed that the minimum residual stress observed in a component was related to an actual height from the base and was not affected by the build height of the sample. Maximum residual stresses were observed closest to the base of the cylinder and the stresses were larger in larger samples for both hoop and longitudinal surface residual stress. The micro-hardness of the samples increased as build height increased. The tensile strength remained within constant range between 1080 MPa and 1050 MPa for all samples successfully tested. Brittle failures were observed on the upper sections of the larger samples, attributed to the high micro-hardness observed in these areas. The study successfully evaluated the relationship between build height and surface residual stresses as well as build height and static mechanical properties thereby increasing the knowledge within this field.
- Full Text:
- Date Issued: 2018
- Authors: Swan, Lindsay Jane
- Date: 2018
- Subjects: Titanium alloys Pulsed laser deposition
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/23537 , vital:30577
- Description: Ti6Al4V is the most commonly used of the titanium alloys and is known for its high strength to weight ratio and superb corrosion resistance compared to conventional steels. Ti6Al4V is used in applications in the aerospace, biomedical, automotive, power generation and oil and gas fields. Laser metal deposition (LMD) is an additive manufacturing (AM) platform used to build 3-D metal shapes. LMD is one of the most researched topics within the laser processing field currently and is advancing continuously. The rapid growth in the AM field is driven by market demands to reduce manufacturing costs, shorter lead times and an increasing demand for customized products. One of the major challenges facing the production of Ti6Al4V components using LMD is the high resultant residual stresses, limiting build size due to delamination or distortion. At the commencement of this study, little data pertaining to the residual stress build up in larger LMD components was available. This research was conducted to create an understanding of the relationship between build height and surface residual stresses and how they influence the dimensional stability of a part. Additionally, the relationship between build height and static mechanical properties was analysed. The effects of laser power, scanning speed and powder mass flow rate on the deposition layer were evaluated. The number of defects and the deposition build height were evaluated to determine the optimum process parameters for multi-layer components. An increase in laser power resulted in an increase in build height for the parameter window selected for the study. Similarly, an increase in build height was observed with an increase in powder mass flow rate, while an increase in scanning speed resulted in a decrease in build height. As laser power and scanning speed had inverse effects on the build height, heat input was evaluated to determine the optimum combination of the 2 parameters. Multilayer samples were produced with a laser power setting of 1900 W, a scanning speed of 0.01 m/s and a powder mass flow rate of 8 g/min. Fully dense components were produced with no notable defects. These components were analysed to reveal the relationship between build height and surface residual stresses and showed that the minimum residual stress observed in a component was related to an actual height from the base and was not affected by the build height of the sample. Maximum residual stresses were observed closest to the base of the cylinder and the stresses were larger in larger samples for both hoop and longitudinal surface residual stress. The micro-hardness of the samples increased as build height increased. The tensile strength remained within constant range between 1080 MPa and 1050 MPa for all samples successfully tested. Brittle failures were observed on the upper sections of the larger samples, attributed to the high micro-hardness observed in these areas. The study successfully evaluated the relationship between build height and surface residual stresses as well as build height and static mechanical properties thereby increasing the knowledge within this field.
- Full Text:
- Date Issued: 2018
Characterizing early drug resistance-related events using geometric ensembles from HIV protease dynamics:
- Amamuddy, Olivier S, Bishop, Nigel T, Tastan Bishop, Özlem
- Authors: Amamuddy, Olivier S , Bishop, Nigel T , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148126 , vital:38712 , DOI: 10.1038/s41598-018-36041-8
- Description: The use of antiretrovirals (ARVs) has drastically improved the life quality and expectancy of HIV patients since their introduction in health care. Several millions are still afflicted worldwide by HIV and ARV resistance is a constant concern for both healthcare practitioners and patients, as while treatment options are finite, the virus constantly adapts via complex mutation patterns to select for resistant strains under the pressure of drug treatment. The HIV protease is a crucial enzyme for viral maturation and has been a game changing drug target since the first application. Due to similarities in protease inhibitor designs, drug cross-resistance is not uncommon across ARVs of the same class.
- Full Text:
- Date Issued: 2018
- Authors: Amamuddy, Olivier S , Bishop, Nigel T , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148126 , vital:38712 , DOI: 10.1038/s41598-018-36041-8
- Description: The use of antiretrovirals (ARVs) has drastically improved the life quality and expectancy of HIV patients since their introduction in health care. Several millions are still afflicted worldwide by HIV and ARV resistance is a constant concern for both healthcare practitioners and patients, as while treatment options are finite, the virus constantly adapts via complex mutation patterns to select for resistant strains under the pressure of drug treatment. The HIV protease is a crucial enzyme for viral maturation and has been a game changing drug target since the first application. Due to similarities in protease inhibitor designs, drug cross-resistance is not uncommon across ARVs of the same class.
- Full Text:
- Date Issued: 2018
Chasing shadow and make believe
- Authors: Mofokeng, Reikanne
- Date: 2018
- Subjects: Creative writing (Higher education) -- South Africa , South African fiction (English) -- 21st century , Science fiction, South African (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63626 , vital:28449
- Description: My thesis is a science fiction novella. It follows the story of an adolescent boy, Shadow, and a little girl, Makebelieve, in an ahistorical future. The world that they traverse is earth, after being nursed back to health, by technologically advanced Southern African societies. A series of inexplicable astronomical events leads to their being hunted down. Through the travels of Shadow and Makebelieve I show how the world and the societies around them operate. I am inspired by Samuel R Delaney’s Aye, Gomorrah and Derrick Bell’s The Space Traders, because of their prowess in world building and exploration of complex and innovative ideas.
- Full Text:
- Date Issued: 2018
- Authors: Mofokeng, Reikanne
- Date: 2018
- Subjects: Creative writing (Higher education) -- South Africa , South African fiction (English) -- 21st century , Science fiction, South African (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63626 , vital:28449
- Description: My thesis is a science fiction novella. It follows the story of an adolescent boy, Shadow, and a little girl, Makebelieve, in an ahistorical future. The world that they traverse is earth, after being nursed back to health, by technologically advanced Southern African societies. A series of inexplicable astronomical events leads to their being hunted down. Through the travels of Shadow and Makebelieve I show how the world and the societies around them operate. I am inspired by Samuel R Delaney’s Aye, Gomorrah and Derrick Bell’s The Space Traders, because of their prowess in world building and exploration of complex and innovative ideas.
- Full Text:
- Date Issued: 2018
Chemical transformation and phytochemical studies of bioactive constituents from extract of callistemon citrinus (curtis) skeels
- Authors: Larayetan, Rotimi Abisoye
- Date: 2018
- Subjects: Callistemon Wild flowers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9122 , vital:34272
- Description: Callistemon citrinus belongs to the family Myrtaceae and exhibits therapeutic activities. The aerial parts of this plant are used to treat different ailments, among them are parasitic infections. The leaves, flowers and stems of Callistemon citrinus were subjected to hydrodistillation. The oils collected were studied by GC-MS analysis for the essential constituents. The overall phenolic content of the leaves oil, radical scavenging, antibacterial action and antioxidant activities of the essential oils of Callistemon citrinus were determined using standard methods, with free radical DPPH or ABTS as reference antioxidants. Chemical transformation of the components was examined for a whole year. A relationship between the chemical change in the volatile oil constituents, antioxidant capacity, percentage yield of the oil of Callistemon citrinus and fluctuation in season has been established. Active phytochemicals present in both ethyl acetate and methanolic extracts of Callistemon citrinus were determined spectrophotometrically. The antimicrobial properties, time of kill, and antioxidant activity of the extracts were explored. The bioactive components were characterized by high level of fatty acids. Squalene, a triterpenoid synthesized in human liver was obtained in the two extracts at varying amounts. The ethyl acetate extract demonstrated strong activity against P. aeruginosa ACC (28.7 ± 1.2 mm), Listeria ACC (26.0 ± 2.0 mm) and Escherichia coli ATCC 35150 (24.0 ± 3.5 mm). Qualitative phytochemical screening revealed the presence of alkaloids, glycosides, saponins, steroids and triterpenoids, fats and oils, flavonoids, phenols and tannins in them. In the quantitative phytochemical determination (total tannin, total flavonoids and flavonols, total phenolic and total antioxidant capacity) were carried out. The minimum time needed to kill the tested bacterial strains totally ranged from 15 to 24 hours. The aqueous extracts used for biosynthesis of nanoparticles were obtained from the fresh aerial parts of the plant. The biosynthesized gold and silver nanoparticles (AuNPs and AgNPs) of the aqueous extracts of the seed, flower and leaf of the plant, which are active as reducing and capping agents, were characterized using UV-VIS spectrophotometry, XRD, SEM, EDS, TEM, and FT IR. The XRD analysis revealed that the AgNPs were crystalline and the TEM showed that the shapes were spherical with an average size of 29 nm. For AuNPs, an average particle size of about 37 nm was confirmed by the TEM while the morphology and composition of the AuNPs were ascertained by SEM and EDS micrographs; uneven spherical shaped nanoparticles were established by the SEM. Both SEM and EDS demonstrated triangular shaped materials made up of silver and oxygen only. Absorption spectra confirmed by UV-VIS signify the dispersed nature of the synthesized nanoparticles with absorption band observed at 280 nm for the leaf AgNPs. FT IR had absorption bands at about 1700 cm-1 establishing the C=O stretching due to the amide bond while the FT IR for the AuNPs showed an absorption peak at 230 cm-1 confirming the presence of gold nanoparticles. The phytochemical investigation, isolation and characterization of the bioactive compounds of various organic crude extracts like hexane, dichloromethane, methanol and ethyl acetate were as well carried out, and the compounds responsible for their medicinal actions were determined. The results from different experiments revealed that the leaves and flowers of Callistemon citrinus possessed phenolic compounds and cyclic ethers with a variety of pharmacological action. The ethyl acetate and methanol crude extracts were found to possess broad spectrum of antimicrobial activities and pharmaceutically essential bioactive components with striking antioxidant capacities that may be used in the synthesis of novel drugs for the management of different ailments. The AuNPs and AgNPs synthesized from the seed, flower and leaf extracts of Callistemon citrinus where found to have prominent antimalarial, antiplasmodial, and antibacterial activities. The biosynthesized nanoparticles inhibit all the bacterial strains used and they were not cytotoxic to Hela cells, confirming their prospect for use as an excellent source for naturally occurring drugs against malaria, cell cytotoxicity, trypanosomes, and microbial infection. Similarly the crude organic extracts and the fractions derived from them exhibited high antimalarial and antitrypanosomal activities, but they were toxic to Hela cells. This is an indication that they will not be safe for use as targeted drugs for mammalian organism.
- Full Text:
- Date Issued: 2018
- Authors: Larayetan, Rotimi Abisoye
- Date: 2018
- Subjects: Callistemon Wild flowers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9122 , vital:34272
- Description: Callistemon citrinus belongs to the family Myrtaceae and exhibits therapeutic activities. The aerial parts of this plant are used to treat different ailments, among them are parasitic infections. The leaves, flowers and stems of Callistemon citrinus were subjected to hydrodistillation. The oils collected were studied by GC-MS analysis for the essential constituents. The overall phenolic content of the leaves oil, radical scavenging, antibacterial action and antioxidant activities of the essential oils of Callistemon citrinus were determined using standard methods, with free radical DPPH or ABTS as reference antioxidants. Chemical transformation of the components was examined for a whole year. A relationship between the chemical change in the volatile oil constituents, antioxidant capacity, percentage yield of the oil of Callistemon citrinus and fluctuation in season has been established. Active phytochemicals present in both ethyl acetate and methanolic extracts of Callistemon citrinus were determined spectrophotometrically. The antimicrobial properties, time of kill, and antioxidant activity of the extracts were explored. The bioactive components were characterized by high level of fatty acids. Squalene, a triterpenoid synthesized in human liver was obtained in the two extracts at varying amounts. The ethyl acetate extract demonstrated strong activity against P. aeruginosa ACC (28.7 ± 1.2 mm), Listeria ACC (26.0 ± 2.0 mm) and Escherichia coli ATCC 35150 (24.0 ± 3.5 mm). Qualitative phytochemical screening revealed the presence of alkaloids, glycosides, saponins, steroids and triterpenoids, fats and oils, flavonoids, phenols and tannins in them. In the quantitative phytochemical determination (total tannin, total flavonoids and flavonols, total phenolic and total antioxidant capacity) were carried out. The minimum time needed to kill the tested bacterial strains totally ranged from 15 to 24 hours. The aqueous extracts used for biosynthesis of nanoparticles were obtained from the fresh aerial parts of the plant. The biosynthesized gold and silver nanoparticles (AuNPs and AgNPs) of the aqueous extracts of the seed, flower and leaf of the plant, which are active as reducing and capping agents, were characterized using UV-VIS spectrophotometry, XRD, SEM, EDS, TEM, and FT IR. The XRD analysis revealed that the AgNPs were crystalline and the TEM showed that the shapes were spherical with an average size of 29 nm. For AuNPs, an average particle size of about 37 nm was confirmed by the TEM while the morphology and composition of the AuNPs were ascertained by SEM and EDS micrographs; uneven spherical shaped nanoparticles were established by the SEM. Both SEM and EDS demonstrated triangular shaped materials made up of silver and oxygen only. Absorption spectra confirmed by UV-VIS signify the dispersed nature of the synthesized nanoparticles with absorption band observed at 280 nm for the leaf AgNPs. FT IR had absorption bands at about 1700 cm-1 establishing the C=O stretching due to the amide bond while the FT IR for the AuNPs showed an absorption peak at 230 cm-1 confirming the presence of gold nanoparticles. The phytochemical investigation, isolation and characterization of the bioactive compounds of various organic crude extracts like hexane, dichloromethane, methanol and ethyl acetate were as well carried out, and the compounds responsible for their medicinal actions were determined. The results from different experiments revealed that the leaves and flowers of Callistemon citrinus possessed phenolic compounds and cyclic ethers with a variety of pharmacological action. The ethyl acetate and methanol crude extracts were found to possess broad spectrum of antimicrobial activities and pharmaceutically essential bioactive components with striking antioxidant capacities that may be used in the synthesis of novel drugs for the management of different ailments. The AuNPs and AgNPs synthesized from the seed, flower and leaf extracts of Callistemon citrinus where found to have prominent antimalarial, antiplasmodial, and antibacterial activities. The biosynthesized nanoparticles inhibit all the bacterial strains used and they were not cytotoxic to Hela cells, confirming their prospect for use as an excellent source for naturally occurring drugs against malaria, cell cytotoxicity, trypanosomes, and microbial infection. Similarly the crude organic extracts and the fractions derived from them exhibited high antimalarial and antitrypanosomal activities, but they were toxic to Hela cells. This is an indication that they will not be safe for use as targeted drugs for mammalian organism.
- Full Text:
- Date Issued: 2018
Chemical weathering on selected nunataks in western Dronning Maud Land, Antarctica
- Authors: Knox, Jenna Tracy
- Date: 2018
- Subjects: Glacial climates -- Antarctica -- Queen Maud Land , Glaciology -- Antarctica -- Queen Maud Land , Chemical weathering -- Antarctica -- Queen Maud Land , Atmospheric carbon dioxide -- Environmental aspects , Climatic changes -- Antarctica -- Queen Maud Land , Nunataks -- Antarctica -- Queen Maud Land
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61658 , vital:28046
- Description: High latitude areas are sensitive to the impacts of climate change, and it is expected that the impact of greenhouse warming will be much higher in the polar regions than in any other climatic zones, with the most highly affected area being that of the Antarctic rim (Barsch, 1993). Weathering and pedogenic processes respond to variations in climate, with models predicting that chemical weathering may increase synchronously with global carbon dioxide levels increase, due to dissolution rates and the erosional impact of hydrological cycles in warming climates (Anderson & Anderson, 2010). As liquid water becomes more available in Antarctica the potential for chemical weathering, due to a less moisture-limited environment and increased temperatures, increases (Convey et al., 2009). Weathering processes are important for soil formation and the production of fine-grained material, with chemical weathering being an active constituent of this. Increased rates of soil formation are likely to occur, with global climate changes resulting in greater chemical weathering occurring in Antarctica. Opportunistic sampling was conducted during the Austral summer of 2016/2017, whereby rock, snow and meltwater samples were taken at various sites within the western portion of Dronning Maud Land of Antarctica. Rock samples were placed in resin, and cut with a diamond saw to create thin sections. Optical microscopy and scanning transmission electron microscopy (STEM) were used to analyse mineral weight percentage with depth. Twelve soil samples were dried and weighed, sieved and statistically represented according to particle size. Inductively coupled plasma mass spectrometry (ICP-MS) determined the geochemical analysis for 10 water and snow samples. Rock hardness was inferred through the use of an Equotip, with rebound values recorded for multiple rock faces and samples. Thermal regimes of rock temperature was further recorded using a FLIR infrared camera, and documented for each rock face over a 24 hour period at 2 hourly intervals. The products of increased chemical weathering were evident from particle size analysis; samples were very poorly sorted in nature, and undergo in situ weathering, whereby products were not removed by erosional processes. Weathering rinds were found to be siliceous and ferric, depending on parent lithology. Ferric ratios increased in wt.% from the substrate rock to the external surface, creating the red, iron rich crusts noted on the hand specimens. The observable chemical weathering was found adjacent to intrusions through Precambrian dolerites. Geochemical analysis revealed thin, carbonaceous features, with impurity-rich layers, characteristic of speleothem formation. Carbonaceous layers did not follow underlying substrate features, rather deposited at the external surface, upon which, further precipitation growth could occur, creating karst features. Extensive gypsum coatings (>2mm) under BSE imagery were identified, with the abundance of gypsum salts (below surface level) and rock coatings indicating active sulphuric acid weathering, in western Dronning Maud Land, Antarctica. Were mechanical processes faster than chemical, weathering rinds and solution features on silicate rocks would be uncommon in the Antarctic, periglacial landscape. However, this is not the case as the existence of these landforms implies that chemical weathering may occur faster than mechanical weathering processes (Pope et al., 1995). In a changing world, one needs to monitor these processes at a micro-scale in order to fully understand how periglacial environments react to global climatic changes, and the subsequent impacts on these sensitive environments.
- Full Text:
- Date Issued: 2018
- Authors: Knox, Jenna Tracy
- Date: 2018
- Subjects: Glacial climates -- Antarctica -- Queen Maud Land , Glaciology -- Antarctica -- Queen Maud Land , Chemical weathering -- Antarctica -- Queen Maud Land , Atmospheric carbon dioxide -- Environmental aspects , Climatic changes -- Antarctica -- Queen Maud Land , Nunataks -- Antarctica -- Queen Maud Land
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61658 , vital:28046
- Description: High latitude areas are sensitive to the impacts of climate change, and it is expected that the impact of greenhouse warming will be much higher in the polar regions than in any other climatic zones, with the most highly affected area being that of the Antarctic rim (Barsch, 1993). Weathering and pedogenic processes respond to variations in climate, with models predicting that chemical weathering may increase synchronously with global carbon dioxide levels increase, due to dissolution rates and the erosional impact of hydrological cycles in warming climates (Anderson & Anderson, 2010). As liquid water becomes more available in Antarctica the potential for chemical weathering, due to a less moisture-limited environment and increased temperatures, increases (Convey et al., 2009). Weathering processes are important for soil formation and the production of fine-grained material, with chemical weathering being an active constituent of this. Increased rates of soil formation are likely to occur, with global climate changes resulting in greater chemical weathering occurring in Antarctica. Opportunistic sampling was conducted during the Austral summer of 2016/2017, whereby rock, snow and meltwater samples were taken at various sites within the western portion of Dronning Maud Land of Antarctica. Rock samples were placed in resin, and cut with a diamond saw to create thin sections. Optical microscopy and scanning transmission electron microscopy (STEM) were used to analyse mineral weight percentage with depth. Twelve soil samples were dried and weighed, sieved and statistically represented according to particle size. Inductively coupled plasma mass spectrometry (ICP-MS) determined the geochemical analysis for 10 water and snow samples. Rock hardness was inferred through the use of an Equotip, with rebound values recorded for multiple rock faces and samples. Thermal regimes of rock temperature was further recorded using a FLIR infrared camera, and documented for each rock face over a 24 hour period at 2 hourly intervals. The products of increased chemical weathering were evident from particle size analysis; samples were very poorly sorted in nature, and undergo in situ weathering, whereby products were not removed by erosional processes. Weathering rinds were found to be siliceous and ferric, depending on parent lithology. Ferric ratios increased in wt.% from the substrate rock to the external surface, creating the red, iron rich crusts noted on the hand specimens. The observable chemical weathering was found adjacent to intrusions through Precambrian dolerites. Geochemical analysis revealed thin, carbonaceous features, with impurity-rich layers, characteristic of speleothem formation. Carbonaceous layers did not follow underlying substrate features, rather deposited at the external surface, upon which, further precipitation growth could occur, creating karst features. Extensive gypsum coatings (>2mm) under BSE imagery were identified, with the abundance of gypsum salts (below surface level) and rock coatings indicating active sulphuric acid weathering, in western Dronning Maud Land, Antarctica. Were mechanical processes faster than chemical, weathering rinds and solution features on silicate rocks would be uncommon in the Antarctic, periglacial landscape. However, this is not the case as the existence of these landforms implies that chemical weathering may occur faster than mechanical weathering processes (Pope et al., 1995). In a changing world, one needs to monitor these processes at a micro-scale in order to fully understand how periglacial environments react to global climatic changes, and the subsequent impacts on these sensitive environments.
- Full Text:
- Date Issued: 2018
Children in conflict with the law - constructions of their family environment
- Mtshutshwane, Anda Sweetgirl, Terblanche, Susan
- Authors: Mtshutshwane, Anda Sweetgirl , Terblanche, Susan
- Date: 2018
- Subjects: Juvenile delinquency -- South Africa -- Eastern Cape , Child development -- South Africa -- Eastern Cape , Problem children -- South Africa -- Eastern Cape , Children -- Legal status, laws, etc. -- South Africa -- Eastern Cape , Crime and age -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/32960 , vital:32480
- Description: The studies reviewed for this project indicate that there is an interplay of family and social factors that affect the development of the child. Furthermore, some studies postulate that there is a relationship between children’s engagement in criminal behaviour and their family environment. The present study aimed to explore, describe and interpret how children who have been in conflict with the law construct their family environment. A qualitative research approach that was embedded in an explorative, descriptive and contextual research design was employed in order to achieve the objectives of the study. The research population was constituted of children from a Child and Youth Care Centre. A non-probability purposive sampling technique was employed to select children aged 14 to 17 years who have been in conflict with the law. Individual semi-structured interviews were conducted with the selected children and this data was analyzed using Tesch’s thematic analysis. Ethical considerations that were applicable for the involvement of children and vulnerable groups in research were adhered to. The trustworthiness of the research process, and the findings of the study, were enhanced by employing a variety of data verification strategies. Data was verified using: member checking, peer debriefing, clarifying bias by the researcher, and dense description of the application of the selected methods used in research suggested by Creswell. The major findings of this study include: positive and negative experiences of children prior to involvement to crime in their internal family environment. The external family environment was dominated by gangsterism and crime in the community, police corruption and their interaction with drugs. Furthermore, the study findings revealed positive and negative school experiences and posited several reasons why children break the law. It is hoped that the research will contribute to the knowledge base of Social Work and Practice interventions in the field of child protection services in general and, more specifically, on the criminal justice system.
- Full Text:
- Date Issued: 2018
- Authors: Mtshutshwane, Anda Sweetgirl , Terblanche, Susan
- Date: 2018
- Subjects: Juvenile delinquency -- South Africa -- Eastern Cape , Child development -- South Africa -- Eastern Cape , Problem children -- South Africa -- Eastern Cape , Children -- Legal status, laws, etc. -- South Africa -- Eastern Cape , Crime and age -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/32960 , vital:32480
- Description: The studies reviewed for this project indicate that there is an interplay of family and social factors that affect the development of the child. Furthermore, some studies postulate that there is a relationship between children’s engagement in criminal behaviour and their family environment. The present study aimed to explore, describe and interpret how children who have been in conflict with the law construct their family environment. A qualitative research approach that was embedded in an explorative, descriptive and contextual research design was employed in order to achieve the objectives of the study. The research population was constituted of children from a Child and Youth Care Centre. A non-probability purposive sampling technique was employed to select children aged 14 to 17 years who have been in conflict with the law. Individual semi-structured interviews were conducted with the selected children and this data was analyzed using Tesch’s thematic analysis. Ethical considerations that were applicable for the involvement of children and vulnerable groups in research were adhered to. The trustworthiness of the research process, and the findings of the study, were enhanced by employing a variety of data verification strategies. Data was verified using: member checking, peer debriefing, clarifying bias by the researcher, and dense description of the application of the selected methods used in research suggested by Creswell. The major findings of this study include: positive and negative experiences of children prior to involvement to crime in their internal family environment. The external family environment was dominated by gangsterism and crime in the community, police corruption and their interaction with drugs. Furthermore, the study findings revealed positive and negative school experiences and posited several reasons why children break the law. It is hoped that the research will contribute to the knowledge base of Social Work and Practice interventions in the field of child protection services in general and, more specifically, on the criminal justice system.
- Full Text:
- Date Issued: 2018
Chipangano: vigilantism and community responses in Mbare District, Zimbabwe, c.2000-2013
- Authors: Munyarari, Tinashe
- Date: 2018
- Subjects: Vigilantism Zimbabwe Mbare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe History 1980- , Vigilantism Zimbabwe Mbare Public opinion , Collective memory Zimbabwe Mbare
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62126 , vital:28130
- Description: This study examines an aspect of Zimbabwe’s political history, namely the emergence and operations of Chipangano vigilante group in Mbare (2000-2013) and how the community responded to the scourges of this vigilante group. This study shows that Chipangano, which means a pact, was formed with the intention to extend ZANU-PF patronage system, canvassing support and regain control of Mbare district from the MDC. The group consolidated itself as a shadow militia group for ZANU-PF that intimidated the opposition parties and coerced the general populace to attend ZANU-PF functions. It also shows that the vigilante group seized Harare City Council’s duties, such as collecting gate-takings from local and long distance public transport at Mbare Bus Terminal; controlling allocations of market stalls and collecting rents from market stalls, for personal benefits. The group also politicised the access to local state property. Chipangano’s collusion with ZANU-PF and state structures licensed it to engage in criminal activities with impunity, thus this thesis seeks to understand the relationship between the vigilantes, ZANU-PF and state structures. The activities of Chipangano such as abduction, intimidation, beatings, killings and displacement of people resulted in social trauma. This thesis will also explore how this phase of violence is remembered today by the research informants. , Thesis (MA) -- Faculty of Humanities, History, 2018
- Full Text:
- Date Issued: 2018
- Authors: Munyarari, Tinashe
- Date: 2018
- Subjects: Vigilantism Zimbabwe Mbare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe History 1980- , Vigilantism Zimbabwe Mbare Public opinion , Collective memory Zimbabwe Mbare
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62126 , vital:28130
- Description: This study examines an aspect of Zimbabwe’s political history, namely the emergence and operations of Chipangano vigilante group in Mbare (2000-2013) and how the community responded to the scourges of this vigilante group. This study shows that Chipangano, which means a pact, was formed with the intention to extend ZANU-PF patronage system, canvassing support and regain control of Mbare district from the MDC. The group consolidated itself as a shadow militia group for ZANU-PF that intimidated the opposition parties and coerced the general populace to attend ZANU-PF functions. It also shows that the vigilante group seized Harare City Council’s duties, such as collecting gate-takings from local and long distance public transport at Mbare Bus Terminal; controlling allocations of market stalls and collecting rents from market stalls, for personal benefits. The group also politicised the access to local state property. Chipangano’s collusion with ZANU-PF and state structures licensed it to engage in criminal activities with impunity, thus this thesis seeks to understand the relationship between the vigilantes, ZANU-PF and state structures. The activities of Chipangano such as abduction, intimidation, beatings, killings and displacement of people resulted in social trauma. This thesis will also explore how this phase of violence is remembered today by the research informants. , Thesis (MA) -- Faculty of Humanities, History, 2018
- Full Text:
- Date Issued: 2018
Citizen science, treatment and microbial compliance monitoring in rainwater harvesting in Namibia
- Angala, Hallo Angaleni Nameya
- Authors: Angala, Hallo Angaleni Nameya
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62082 , vital:28105
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
- Authors: Angala, Hallo Angaleni Nameya
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62082 , vital:28105
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Classification of Distinct Fuzzy Subgroups of the Dihedral Group Dp nq for p and q distinct primes and n ∈ N
- Authors: Nxala, Baphumelele Ellen
- Date: 2018
- Subjects: Fuzzy mathematics Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14516 , vital:39997
- Description: In this dissertation, we classify distinct fuzzy subgroups of the dihedral group Dpnq, for p and q distinct primes and n ∈ N, under a natural equivalence relation of fuzzy subgroups and a fuzzy isomorphism. We aim to present formulae for the number of maximal chains and the number of distinct fuzzy subgroups of this group. Our study will include some theory on non-abelian groups since the classification of distinct fuzzy subgroups of this group relies on the crisp characterization of maximal chains. We give the definition of a natural equivalence relation introduced by Murali and Makamba in [67] which we will use in this study. Based on this definition, we introduce two counting techniques that we will use to compute the number of distinct fuzzy subgroups of Dpnq. In this dissertation, we use the criss-cut counting technique as our primary method of enumeration, and the cross-cut method serves as a means of verifying results we obtain from our primary method. To classify distinct fuzzy subgroups of this group, we begin by investigating the dihedral groups Dpnq, for p and q distinct primes and specific values of n = 2 and 3 to observe a trend. We classify the flags of these groups using the characterization of flags introduced in [93]. From this characterization, we then present formulae for the number of distinct fuzzy subgroups attributed to the flags of Dp 2q and Dp 3q . To generalise results for Dpnq, for p and q distinct primes and n ∈ N, we characterize the flags of this group and classify them as either cyclic, mdcyclic for 1 ≤ m ≤ n, or b-cyclic. Finally, we establish a general formula for the number of distinct fuzzy subgroups obtainable from these flags. We conclude by comparing results obtained from using our general formula to those obtained by other researchers for the same group. Based on the results from this study, we give an outline of future research work
- Full Text:
- Date Issued: 2018
- Authors: Nxala, Baphumelele Ellen
- Date: 2018
- Subjects: Fuzzy mathematics Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14516 , vital:39997
- Description: In this dissertation, we classify distinct fuzzy subgroups of the dihedral group Dpnq, for p and q distinct primes and n ∈ N, under a natural equivalence relation of fuzzy subgroups and a fuzzy isomorphism. We aim to present formulae for the number of maximal chains and the number of distinct fuzzy subgroups of this group. Our study will include some theory on non-abelian groups since the classification of distinct fuzzy subgroups of this group relies on the crisp characterization of maximal chains. We give the definition of a natural equivalence relation introduced by Murali and Makamba in [67] which we will use in this study. Based on this definition, we introduce two counting techniques that we will use to compute the number of distinct fuzzy subgroups of Dpnq. In this dissertation, we use the criss-cut counting technique as our primary method of enumeration, and the cross-cut method serves as a means of verifying results we obtain from our primary method. To classify distinct fuzzy subgroups of this group, we begin by investigating the dihedral groups Dpnq, for p and q distinct primes and specific values of n = 2 and 3 to observe a trend. We classify the flags of these groups using the characterization of flags introduced in [93]. From this characterization, we then present formulae for the number of distinct fuzzy subgroups attributed to the flags of Dp 2q and Dp 3q . To generalise results for Dpnq, for p and q distinct primes and n ∈ N, we characterize the flags of this group and classify them as either cyclic, mdcyclic for 1 ≤ m ≤ n, or b-cyclic. Finally, we establish a general formula for the number of distinct fuzzy subgroups obtainable from these flags. We conclude by comparing results obtained from using our general formula to those obtained by other researchers for the same group. Based on the results from this study, we give an outline of future research work
- Full Text:
- Date Issued: 2018
Click chemistry electrode modification using 4-ethynylbenzyl substituted cobalt phthalocyanine for applications in electrocatalysis
- Mpeta, Lekhetho S, Fomo, Gertrude, Nyokong, Tebello
- Authors: Mpeta, Lekhetho S , Fomo, Gertrude , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187626 , vital:44681 , xlink:href="• https://doi.org/10.1080/00958972.2018.1466118"
- Description: In this work, we report on the synthesis and applications of a new cobalt tetrakis 4-((4-ethynylbenzyl) oxy) phthalocyanine (3) for the detection of hydrazine. The glassy carbon electrode (GCE) was first grafted through diazotization, providing the GCE surface layer with azide groups. Thereafter, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper(I) catalyst was used to “click” complex 3 to the grafted surface of GCE. The new platform was then characterized using cyclic voltammetry (CV), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). This work shows that 3 is an effective sensor with sensitivity of 91.5 μA mM−1 and limit of detection of 3.28 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2018
- Authors: Mpeta, Lekhetho S , Fomo, Gertrude , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187626 , vital:44681 , xlink:href="• https://doi.org/10.1080/00958972.2018.1466118"
- Description: In this work, we report on the synthesis and applications of a new cobalt tetrakis 4-((4-ethynylbenzyl) oxy) phthalocyanine (3) for the detection of hydrazine. The glassy carbon electrode (GCE) was first grafted through diazotization, providing the GCE surface layer with azide groups. Thereafter, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper(I) catalyst was used to “click” complex 3 to the grafted surface of GCE. The new platform was then characterized using cyclic voltammetry (CV), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). This work shows that 3 is an effective sensor with sensitivity of 91.5 μA mM−1 and limit of detection of 3.28 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2018
Cloud computing adoption: Strategies for Sub-Saharan Africa SMEs for enhancing competitiveness
- Authors: Adane, Martin
- Date: 2018
- Subjects: business intelligence small businesses business planning Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6862 , vital:51101 , xlink:href="https://doi.org/10.1080/20421338.2018.1439288"
- Description: Small and medium-sized enterprises (SMEs) need to design and implement strategies for adopting new technologies as a competitive tool for maintaining their competitive advantage and cloud computing is at its peak. Since its emergence, there has been a surge in the adoption of cloud computing with research into its adoption primarily concentrated on bigger firms. However, a major characteristic of cloud computing is the anticipated possibilities it holds for SMEs. This paper primarily explores cloud computing adoption strategies for SMEs operating in Sub-Saharan Africa. Using a mixed method approach, a sample of 261 respondents and 11 SMEs was respectively used for the quantitative and qualitative stages of the research. The results reveal that, even though SMEs have their unique expectations for adopting cloud computing, they were of the consensus that elements of an adoption strategy should include adoption goals, a roadmap, and considerations. The paper makes specific recommendations to SMEs to develop adoption strategies that meet their specific needs if they expect cloud computing to play a stronger role to support more strategic initiatives to grow their businesses and improve customer experience.
- Full Text:
- Date Issued: 2018
- Authors: Adane, Martin
- Date: 2018
- Subjects: business intelligence small businesses business planning Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6862 , vital:51101 , xlink:href="https://doi.org/10.1080/20421338.2018.1439288"
- Description: Small and medium-sized enterprises (SMEs) need to design and implement strategies for adopting new technologies as a competitive tool for maintaining their competitive advantage and cloud computing is at its peak. Since its emergence, there has been a surge in the adoption of cloud computing with research into its adoption primarily concentrated on bigger firms. However, a major characteristic of cloud computing is the anticipated possibilities it holds for SMEs. This paper primarily explores cloud computing adoption strategies for SMEs operating in Sub-Saharan Africa. Using a mixed method approach, a sample of 261 respondents and 11 SMEs was respectively used for the quantitative and qualitative stages of the research. The results reveal that, even though SMEs have their unique expectations for adopting cloud computing, they were of the consensus that elements of an adoption strategy should include adoption goals, a roadmap, and considerations. The paper makes specific recommendations to SMEs to develop adoption strategies that meet their specific needs if they expect cloud computing to play a stronger role to support more strategic initiatives to grow their businesses and improve customer experience.
- Full Text:
- Date Issued: 2018
Co-Production of trust for effective local Governance: a case study of Nelson Mandela Bay Municipality
- Authors: Salie-Jakoet, Amina
- Date: 2018
- Subjects: Corporate governance--South Africa--Nelson Mandela Bay Municipality Economic development--South Africa--Nelson Mandela Bay Municipality , Municipal officials and employees--South Africa-- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20308 , vital:29228
- Description: This study acknowledged that while it might be true that protests often turn violent after formal channels have been exhausted, there is an underlying problem of lack of public participation, coproduction and a general lack of trust in and within local government institutions in South Africa. The study therefore proposes that public participation in the municipal governing process is more complex than anticipated. For purposes of data collection, a mixed methods research methodology was adopted and a number of salient recommendations are provided to address the levels of trust within local government. A normative model to enhance coproduction of trust between communities and local government has been proposed. The research is scientifically worthy of distribution to the broader academic community and a number of papers both nationally and internationally have been presented from it.
- Full Text:
- Date Issued: 2018
- Authors: Salie-Jakoet, Amina
- Date: 2018
- Subjects: Corporate governance--South Africa--Nelson Mandela Bay Municipality Economic development--South Africa--Nelson Mandela Bay Municipality , Municipal officials and employees--South Africa-- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20308 , vital:29228
- Description: This study acknowledged that while it might be true that protests often turn violent after formal channels have been exhausted, there is an underlying problem of lack of public participation, coproduction and a general lack of trust in and within local government institutions in South Africa. The study therefore proposes that public participation in the municipal governing process is more complex than anticipated. For purposes of data collection, a mixed methods research methodology was adopted and a number of salient recommendations are provided to address the levels of trust within local government. A normative model to enhance coproduction of trust between communities and local government has been proposed. The research is scientifically worthy of distribution to the broader academic community and a number of papers both nationally and internationally have been presented from it.
- Full Text:
- Date Issued: 2018
Co-production of trust for effective local governance: a case study of the Nelson Mandela Bay Municipality
- Authors: Jakoet-Salie, Amina
- Date: 2018
- Subjects: Public participation -- South Africa -- Nelson Mandela Bay Local government -- South Africa -- Nelson Mandela Bay
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20297 , vital:29227
- Description: The primary aim of this study was to establish whether co-production of public services will lead to trust in service delivery and ultimately to trust in government, with specific reference to the Nelson Mandela Bay Municipality (NMBM). Furthermore, this research investigatedthe fundamental reasons for the mistrust in government, in lieu of the ongoing service delivery protests and officials who are at times not held accountable for their actions. This study acknowledges that there is an underlying problem of lack ofpublic participation and co-production at the sphere of local government.This research is solely based on the assumption thatif co-production is non-existent or problematic and if communities lose trust in the performance of municipalities, any attempts by the government to address these challenges relating to effective governance would be ineffective.The studyprovidesan in-depth theoretical review on co-production, public participation, citizen engagement and trust, with reference to both the national and international context. The study employed both quantitative and qualitative research approaches to validate the research questions and authenticate the problem statement. The triangulation approach allowed the researcher to effectively engage the strengths of both research methodologies. The research findings from the empirical survey were statistically analysed using statistical procedures. The data analysis, derived from the qualitative research approach, involved thematic content analysis. The sample populations for the study comprised councillors selected senior officials and ward committee members. For the quantitative approach, questionnaires were employed for the councillors and the officials. Focus group interviews were conducted with ward committee members as the qualitative component of the study. The findings of the study revealed that as a result of communities’ increasing lack of trust and confidence in local government, service delivery protests are increasing.The study further indicated thatcommunities in the NMBM are generally not well informed about the development plans of the municipality and do not adequately participate in local government activities.The findings from the focus group interviewsconcluded that the working relationship between the ward councillors and ward committee members was somewhat strained and this could have a negative impact on service delivery and ultimately trust levels.Recommendations emanating from the empirical survey and focus group interviews are presented to promote public participation and co-production which essentially could lead to an increase in trust in local government. Legislative prescriptions require that communitiesshould actively participate in the decision-making processes at the local sphere of government. In this regard, a normative model is proposed to further enhance this requirement.
- Full Text:
- Date Issued: 2018
- Authors: Jakoet-Salie, Amina
- Date: 2018
- Subjects: Public participation -- South Africa -- Nelson Mandela Bay Local government -- South Africa -- Nelson Mandela Bay
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20297 , vital:29227
- Description: The primary aim of this study was to establish whether co-production of public services will lead to trust in service delivery and ultimately to trust in government, with specific reference to the Nelson Mandela Bay Municipality (NMBM). Furthermore, this research investigatedthe fundamental reasons for the mistrust in government, in lieu of the ongoing service delivery protests and officials who are at times not held accountable for their actions. This study acknowledges that there is an underlying problem of lack ofpublic participation and co-production at the sphere of local government.This research is solely based on the assumption thatif co-production is non-existent or problematic and if communities lose trust in the performance of municipalities, any attempts by the government to address these challenges relating to effective governance would be ineffective.The studyprovidesan in-depth theoretical review on co-production, public participation, citizen engagement and trust, with reference to both the national and international context. The study employed both quantitative and qualitative research approaches to validate the research questions and authenticate the problem statement. The triangulation approach allowed the researcher to effectively engage the strengths of both research methodologies. The research findings from the empirical survey were statistically analysed using statistical procedures. The data analysis, derived from the qualitative research approach, involved thematic content analysis. The sample populations for the study comprised councillors selected senior officials and ward committee members. For the quantitative approach, questionnaires were employed for the councillors and the officials. Focus group interviews were conducted with ward committee members as the qualitative component of the study. The findings of the study revealed that as a result of communities’ increasing lack of trust and confidence in local government, service delivery protests are increasing.The study further indicated thatcommunities in the NMBM are generally not well informed about the development plans of the municipality and do not adequately participate in local government activities.The findings from the focus group interviewsconcluded that the working relationship between the ward councillors and ward committee members was somewhat strained and this could have a negative impact on service delivery and ultimately trust levels.Recommendations emanating from the empirical survey and focus group interviews are presented to promote public participation and co-production which essentially could lead to an increase in trust in local government. Legislative prescriptions require that communitiesshould actively participate in the decision-making processes at the local sphere of government. In this regard, a normative model is proposed to further enhance this requirement.
- Full Text:
- Date Issued: 2018