An artificial neural network approach to predict the effects of formulation and process variables on prednisone release from a multipartite system
- Authors: Manda, Arthur , Walker, Roderick B , Khamanga, Sandile M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183237 , vital:43933 , xlink:href="https://doi.org/10.3390/pharmaceutics11030109"
- Description: The impact of formulation and process variables on the in-vitro release of prednisone from a multiple-unit pellet system was investigated. Box-Behnken Response Surface Methodology (RSM) was used to generate multivariate experiments. The extrusion-spheronization method was used to produce pellets and dissolution studies were performed using United States Pharmacopoeia (USP) Apparatus 2 as described in USP XXIV. Analysis of dissolution test samples was performed using a reversed-phase high-performance liquid chromatography (RP-HPLC) method. Four formulation and process variables viz., microcrystalline cellulose concentration, sodium starch glycolate concentration, spheronization time and extrusion speed were investigated and drug release, aspect ratio and yield were monitored for the trained artificial neural networks (ANN). To achieve accurate prediction, data generated from experimentation were used to train a multi-layer perceptron (MLP) using back propagation (BP) and the Broyden-Fletcher-Goldfarb-Shanno (BFGS) 57 training algorithm until a satisfactory value of root mean square error (RMSE) was observed. The study revealed that the in-vitro release profile of prednisone was significantly impacted by microcrystalline cellulose concentration and sodium starch glycolate concentration. Increasing microcrystalline cellulose concentration retarded dissolution rate whereas increasing sodium starch glycolate concentration improved dissolution rate. Spheronization time and extrusion speed had minimal impact on prednisone release but had a significant impact on extrudate and pellet quality. This work demonstrated that RSM can be successfully used concurrently with ANN for dosage form manufacture to permit the exploration of experimental regions that are omitted when using RSM alone.
- Full Text:
- Date Issued: 2019
An assessment of amount, distribution and use of urban green spaces in small towns of the Eastern Cape
- Authors: Radebe, Denis Siphosihle
- Date: 2019
- Subjects: Urban ecology (Sociology) -- South Africa -- Eastern Cape , Small cities -- South Africa -- Eastern Cape , City planning -- South Africa -- Eastern Cape , Recreation areas -- South Africa -- Eastern Cape , Open spaces -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76447 , vital:30563
- Description: Most regions of the developing world are experiencing large-scale urbanisation, with urban population growth outstripping rural growth. This is most marked in small and medium-sized towns as opposed to megacities. Urbanisation is associated with numerous changes in social, economic and ecological states and dynamics. A key one, of interest in this study, is the sustainability and liveability of the growing towns and cities. The retention, provision and maintenance of multifunctional urban green infrastructure are a core strategy in this regard. This study therefore sought to assess the amount, distribution and use of urban green spaces within South Africa using small towns of the Eastern Cape. The primary research included sixteen aerial images of which eight were historical aerial photographs and another eight were the latest aerial images of the selected study towns. Historical and latest aerial images were digitised to classify the types and calculate the amount of urban green space. GIS mapping, interviews and focus group discussions were conducted with urban residents to understand how these green spaces are used. The analytical tools in this study derived from social science included household surveys of 180 randomly selected respondents in small towns. Fifteen types of green spaces were identified in the sample towns. The study further revealed that green spaces are not distributed equally in different suburbs of small towns, generally being less green spaces, especially formal parks and recreation areas, in poorer areas. The results indicated a decline of green spaces with urbanisation, and most marked in fast growing towns. The results suggested that urban residents frequently visited urban green spaces, with most respondents favouring the use of green spaces for social and cultural benefits. How use of different spaces was strongly gender related, with males favouring less developed green space types (such as commonages and woodlands) and females for formal areas such domestic and institutional gardens and churchyards. Respondents also identified various challenges associated with using and accessing urban green spaces, with pollution, crime and lack of maintenance in particular. The study shows the importance of GIS as a mapping tool that can be used to provide information for ecological planning in rapidly changing urban environment. The research process generated several lessons that need to be taken into consideration when designing urban landscapes, most importantly relating to the diversity, quantity, quality and maintenance of urban green spaces.
- Full Text:
- Date Issued: 2019
An Evaluation of Text Mining Techniques in Sampling of Network Ports from IBR Traffic
- Authors: Chindipha, Stones D , Irwin, Barry V W , Herbert, Alan
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427630 , vital:72452 , https://www.researchgate.net/profile/Stones-Chindi-pha/publication/335910179_An_Evaluation_of_Text_Mining_Techniques_in_Sampling_of_Network_Ports_from_IBR_Traffic/links/5d833084458515cbd1985a38/An-Evaluation-of-Text-Mining-Techniques-in-Sampling-of-Network-Ports-from-IBR-Traffic.pdf
- Description: Information retrieval (IR) has had techniques that have been used to gauge the extent to which certain keywords can be retrieved from a document. These techniques have been used to measure similarities in duplicated images, native language identification, optimize algorithms, among others. With this notion, this study proposes the use of four of the Information Retrieval Techniques (IRT/IR) to gauge the implications of sampling a/24 IPv4 ports into smaller subnet equivalents. Using IR, this paper shows how the ports found in a/24 IPv4 net-block relate to those found in the smaller subnet equivalents. Using Internet Background Radiation (IBR) data that was collected from Rhodes University, the study found compelling evidence of the viability of using such techniques in sampling datasets. Essentially, being able to identify the variation that comes with sampling the baseline dataset. It shows how the various samples are similar to the baseline dataset. The correlation observed in the scores proves how viable these techniques are to quantifying variations in the sampling of IBR data. In this way, one can identify which subnet equivalent best represents the unique ports found in the baseline dataset (IPv4 net-block dataset).
- Full Text:
- Date Issued: 2019
An evaluation of the current extent and potential spread of Black Bass invasions in South Africa
- Authors: Khosa, Dumisani , Marr, Sean M , Wasserman, Ryan J , Zengeya, Tsungai A , Weyl, Olaf L F
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103867 , vital:32317 , https://doi.org/10.1007/s10530-019-01930-0
- Description: Black Bass, a collective name for members of the centrarchid genus Micropterus, are native to North America, but have been introduced globally to enhance recreational angling. This study assessed the distribution of Micropterus salmoides, M. dolomieu and M. punctulatus in South Africa using both formal (survey-based) and informal (tournament data and social media) information sources. Analysis of the distribution data showed habitat bias between the data sources. Survey data from formal information sources were dominated by locality records in riverine environments while those derived from informal information sources focused more on lacustrine habitats. Presence data were used to develop niche models to identify suitable areas for their establishment. The predicted distribution range of M. salmoides revealed a broad suitability over most of South Africa, however, the Cape Fold Ecoregion and all coastal regions were most suitable for the establishment for both M. dolomieu and M. punctulatus. Flow accumulation and precipitation of coldest quarter were the most important environmental variables associated with the presence of all Black Bass species in South Africa. In addition, anthropogenic disturbance such as agricultural activities were associated with the presence of both Smallmouth Bass and Spotted Bass. An extensive area-based invasion debt was observed for all Micropterus spp. The potential for further spread of Black Bass in South Africa is of ecological concern because of their impact on native biota.
- Full Text:
- Date Issued: 2019
An experimental test of the allotonic frequency hypothesis to isolate the effects of light pollution on bat prey selection:
- Authors: Bailey, Lauren A , Brigham, R Mark , Bohn, Shelby J , Boyles, Justin G , Smit, Ben
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158309 , vital:40171 , https://0-doi.org.wam.seals.ac.za/10.1007/s00442-019-04417-w
- Description: Artificial lights may be altering interactions between bats and moth prey. According to the allotonic frequency hypothesis (AFH), eared moths are generally unavailable as prey for syntonic bats (i.e., bats that use echolocation frequencies between 20 and 50 kHz within the hearing range of eared moths) due to the moths’ ability to detect syntonic bat echolocation. Syntonic bats therefore feed mainly on beetles, flies, true bugs, and non-eared moths. The AFH is expected to be violated around lights where eared moths are susceptible to exploitation by syntonic bats because moths’ evasive strategies become less effective. The hypothesis has been tested to date almost exclusively in areas with permanent lighting, where the effects of lights on bat diets are confounded with other aspects of human habitat alteration. We undertook diet analysis in areas with short-term, localized artificial lighting to isolate the effects of artificial lighting and determine if syntonic and allotonic bats (i.e., bats that use echolocation frequencies outside the hearing range of eared moths) consumed more moths under conditions of artificial lights than in natural darkness.
- Full Text:
- Date Issued: 2019
An exploration of how Professional Learning Communities can contribute to the development of teachers’ capabilities and valued functionings in teaching environmental content knowledge in the Life and Living strand in Grade 8 Natural Sciences
- Authors: Thomas, Kgomotso Emily
- Date: 2019
- Subjects: Teachers -- Training of -- South Africa , Teachers -- In-service training -- South Africa , Science teachers -- In-service training -- South Africa , Science -- Study and teaching (Secondary) -- South Africa , Environmental education -- South Africa
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/92584 , vital:30739
- Description: The study explored how professional learning communities can contribute to the development of teachers’ capabilities and achievement of valued functionings related to teaching environmental content knowledge in the Life and Living strand in Grade 8 Natural Sciences. This is in the context of the Curriculum Assessment and Policy Statement (CAPS), which is a content-referenced curriculum that requires active and critical approaches to learning, and to environment and sustainability content. This study is designed as a qualitative case study of a professional support forum (PSF) in the Mahikeng sub-district, in North West. The study made use of questionnaires, observations, interviews and document analysis as data generation methods. The Capability Approach was used as a theoretical and conceptual framework to explore teachers’ valued functionings, as well as the conversion factors related to those functionings. A functioning is defined as what a person values to be or do, hence the term valued beings and doings has been used interchangeably with the term valued functionings throughout the study. The analysis of data was done in three phases. Phase one analysis was inductive with the data from questionnaires, classroom observations, document analysis (work schedules and lesson plans or preparation books). The purpose of this phase was to answer the first research sub-question of how teachers teach environmental content. Phase two was a deductive analysis, and the purpose was to present teachers’ valued beings and doings in teaching environmental content, and in belonging to the PSF. The last phase of analysis was abductive, and it employed the theoretical framework of Sen’s Capability Approach to get a deeper understanding of factors that either enabled or constrained teachers’ valued beings and doings associated with their capabilities. The study found that teachers have gaps in their environmental content knowledge in the Life and Living strand grade 8 Natural Sciences. This was mainly as a result of teachers not having relevant qualifications, and/or not having any professional development in teaching the environmental content knowledge. Secondly, teachers used traditional methods which were teacher-centred to teach environmental content knowledge. The gaps in the environmental content knowledge were constraints to how the teachers taught environmental content in their classrooms. Teachers’ valued beings and doings related to teaching environmental content were discussed under the three conversion factors of the capability approach: personal, social and environmental conversion factors. The study found that teachers’ qualifications, experiences, passion for environmental content topics, level of confidence, teaching and learning resources, learners’ interest and participation, support, classroom and schools’ environment were among conversion factors that either enabled or constrained teachers’ valued functionings in teaching environmental content Findings also revealed that teachers have different valued functionings related to belonging to the PSF: shared responsibilities, shared values and vision, collaboration, and discussion of subject content. The conversion factors related to these functionings were found to be learning space, time and duration of the PSF, activities in the PSF, teaching and learning resources, teaching experience, and facilitation. The study recommends that teachers’ professional development programmes should promote subject content discussions as well as group and individual learning. They should also create supportive conditions that will expand teachers’ capabilities in teaching environmental content knowldge. Lastly, the teachers’ professional development programmes should explicitly take into account teachers’ valued functionings and conversion factors that can enable teachers to develop their professional capabilities.
- Full Text:
- Date Issued: 2019
An exploration of social media as a key site for the expression of post-racial politics
- Authors: Bell, Joshua
- Date: 2019
- Subjects: Social media -- Political aspects -- South Africa , South Africa -- Politics and government -- 1994- , South Africa -- In mass media
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/94049 , vital:30995
- Description: This research sets out to examine colourblind racism in contemporary South Africa, specifically, as expressed on social media networks. In South Africa, a nation lauded for its transition from Apartheid to liberal democracy, racism still continues to exist. In the new democracy, racism continues in old, familiar forms but it has been suggested that racism also assumes new and emergent forms such as ‘colourblind’ racism. This is evident in recent controversies involving local public figures and their expressions of ‘soft’, ‘colourblind’ racism on Facebook. It is the new platforms and modes of racism unique to democratic South Africa which this thesis attempts to explore. Specifically, this study is framed by ‘post-racialism’, a concept developed by scholars globally to capture the suggestion that in liberal democratic societies across the world, racism continues with racial inequality now underpinned by an ideology of colourblindness as opposed to overt policies of segregation. Colourblindness denies the relevance of race as a collective issue, proposing instead that other social factors such as class are more pertinent in considerations of social inequality. The purpose of colourblind narratives may be identified as the reduction of racism to mere individual action, denying systemic white privilege and historical responsibility for reparation as well as preventing racially subjugated groups from critically interrogating racial power and privilege (Goldberg, 2015: 28-30). Post-racial theorists agree that the projection of colourblind politics which claims to no longer ‘see race’ has instead served to secure the normalisation of white privilege and black subjugation (Bonilla-Silva et al, 2004: 559-560). The purported existence of colourblind /post-racial racism and its impact requires exploration in the context of South Africa today. In expanding on the definition of racism, we are able to see that racism is an adaptive system of power that is able to reproduce and reconceptualise itself to changes within society. As modalities of racism have evolved, so have the platforms for its propagation. This research offers social media as a site of exploration for post-racial narratives. The case studies of Penny Sparrow, Helen Zille and Mabel Jansen are presented in this study as exemplars of post-racial liberalism, denial and exclusion. This research calls for the expansion of racial understanding so as to contest racial power structures as a continuing systemic issue in contemporary South Africa.
- Full Text:
- Date Issued: 2019
An explorative study into Faith healing as an African belief system and its influence on the diagnosis and treatment of mental illness in the Eastern Cape province, South Africa
- Authors: Tsotsi, Liso
- Date: 2019
- Subjects: Traditional medicine -- South Africa -- Eastern Cape , Spiritual healing -- South Africa -- Eastern Cape , Ethnopsychology -- South Africa -- Eastern Cape , Mental illness -- Treatment -- South Africa -- Eastern Cape , Mental illness -- Alternative treatment -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/67753 , vital:29137
- Description: The present study specifically focussed on Faith healing as an indigenous healing system and its influence on the diagnosis and treatment of mental illnesses in the Eastern Cape province of South Africa. The study aimed to provide a descriptive overview of Faith healers’ perspectives on the diagnosis and treatment of mental illnesses in the Eastern Cape, as well as to compare conclusions reached with other categories of indigenous healers. The inter-category comparisons on a broader level allowed for a further comparative discourse with the mainstream western medical psychiatric view of mental illness. Therefore, the scope of this study does not include in-depth analyses of findings, but rather the generation of themes for comparative discussions. While there exists vast literature on the diagnostic and treatment perspectives of the other two categories of indigenous healing systems (traditional healers and herbalists), a limited number of studies have been focussed on Faith healing as an indigenous mode of healing. The present study attempted to address this gap in the literature in an effort to promote future collaborative work across all viewpoints, in the management of mental illnesses. This study, grounded in qualitative research, utilized thematic analysis as its theoretical framework. Non probability judgmental sampling was used to secure self-identifying Faith healers, where conclusions from them were drawn from data collected, using in depth semi-structured interviews and observation. The main findings of the study indicated that Faith healers’ perspectives on the diagnosis and treatment of mental illnesses are based mainly on indigenous cultural theories. Furthermore, that collaboration with other viewpoints is hampered by animosity, feelings of distrust and the fear of appearing inferior.
- Full Text:
- Date Issued: 2019
An exploratory case study of accelerator programmes in the Republic of South Africa
- Authors: Mametse, Mmankitseng Lerato
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/92639 , vital:30737
- Description: South Africa is facing a challenge of poverty, unemployment and low growth. Government has identified the small and medium-sized business (SME) sector as one of the ways through which to combat these challenges. Government has also set up programmes and agencies to support SMEs in their search for funding and other kinds of support. South Africa, however, has one of the highest rates of SME failures in the world, with the majority not surviving beyond three years. Alternative interventions are therefore required to support South Africa’s SMEs to become sustainable companies beyond three years and to contribute positively to economic growth, poverty alleviation and job creation. This paper explores one kind of intervention that has been used internationally and that is increasingly being adopted in South Africa. Accelerator programmes, aimed at supporting start-ups to get to the next level of their development, have been growing in numbers around the world, trying to replicate the success of the original accelerator programme – the Y Combinator – which was responsible for the success of household names such as Airbnb and Dropbox. Accelerator programmes help start-up companies define and build their initial products, identify promising customer segments, and secure resources, including capital and employees. By making these necessary resources available to start-ups, it may be possible to ensure that fewer start-ups fail and more SMEs remain sustainable into the future. Several accelerator programmes have been founded in South Africa, all with a similar aim: to accelerate the development of start-ups that have the potential to grow exponentially given access to the right resources. This paper examines how South African accelerator programmes work in terms of the key resources made available to the start-ups that participate in their programmes. An increasing number of academic papers have been written on accelerator programmes internationally, but little information is available for the South African context. This research study investigated the phenomenon of accelerator programmes in South Africa through the lens of Resource-based Theory. The theory posits that, in order to gain a sustained competitive advantage, companies need to utilise their resources (including physical, human and organisational) in a manner that is effective and efficient, both internally and externally. The research answers the following questions: How do accelerator programmes work in South Africa? What value (in terms of resources offered) do they claim to bring to start-ups that go through their accelerator programmes? An exploratory case study method was selected to understand the phenomenon of accelerator programmes in South Africa. Purposeful sampling was used in the selection of accelerator programmes, as it allows for the selection of information-rich cases. The research findings indicate that accelerator programmes in South Africa follow the structure of providing start-ups, over a period between three months and one year, with resources that will assist them to be successful into the future. The investigation finds that human and financial resources are some of the most valuable resources that accelerator programmes provide to start-ups to help progress these start-ups to their next level of development. The most important resource is mentorship from knowledgeable industry players who are themselves entrepreneurs. Access to networks to gain access to the market, as well as funding, is also made available by accelerator programmes. This investigation provides a glimpse of the accelerator programme phenomenon in South Africa and highlights the important role that mentorship from experienced entrepreneurs, and access to markets and funding, play in the development of start-ups.
- Full Text:
- Date Issued: 2019
An Illustration of a Deductive Pattern Matching Procedure in Qualitative Leadership Research:
- Authors: Pearse, Noel
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149895 , vital:38911 , DOI: 10.34190/JBRM.17.3.004
- Description: Most qualitative studies in business-related research have adopted an inductive approach, in that they explore specific cases and then extract themes, or statements that are more general, from this data. This approach has its shortcomings, including not developing a more systematic body of knowledge of behavioural and social processes that take place in organisations. In contrast, in deductive qualitative research, the theoretical propositions derived from a review of the literature serve as its departure point, informing how the data is collected. Later on in the analysis of data, the researcher uses the propositions to determine if the literature explains the case that was being investigated. Unfortunately, given the relative neglect of deductive qualitative research approaches, there is little guidance and few examples offered that illustrate the application of these techniques. This poses a challenge for researchers, who often need a greater level of structure when it comes to designing and conducting their research. Therefore, the aim of this paper is to illustrate the design of a research protocol that integrates two deductive approaches that are suitable for explanatory case study research, namely deductive thematic analysis and pattern matching. This paper develops a sevenstep process that researchers can follow, for carrying out this type of deductive qualitative research. Using extracts from a research study investigating the leading of organisational change, the steps in this process are illustrated.
- Full Text:
- Date Issued: 2019
An integrated framework for assessing coastal community vulnerability across cultures, oceans and scales
- Authors: Aswani, Shankar , Howard, J A , Gasalla, Maria A , Jennings, Sarah , Malherbe, W , Martins, I M , Salim Shyam , Van Putten, Ingrid E , Swathilekshmi, P S , Narayanakumar, R , Watmough G R
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421581 , vital:71863 , xlink:href="https://doi.org/10.1080/17565529.2018.1442795"
- Description: Coastal communities are some of the most at-risk populations with respect to climate change impacts. It is therefore important to determine the vulnerability of such communities to co-develop viable adaptation options. Global efforts to address this issue include international scientific projects, such as Global Learning for Local Solutions (GULLS), which focuses on five fast warming regions of the southern hemisphere and aims to provide an understanding of the local scale processes influencing community vulnerability that can then be up-scaled to regional, country and global levels. This paper describes the development of a new social and ecological vulnerability framework which integrates exposure, sensitivity and adaptive capacity with the social livelihoods and food security approaches. It also measures community flexibility to understand better the adaptive capacity of different levels of community organization. The translation of the conceptual framework to an implementable method is described and its application in a number of “hotspot” countries, where ocean waters are warming faster than the rest of the world, is presented. Opportunities for cross-cultural comparisons to uncover similarities and differences in vulnerability and adaptation patterns among the study’s coastal communities, which can provide accelerated learning mechanisms to other coastal regions, are highlighted. The social and ecological framework and the associated survey approach allow for future integration of local-level vulnerability data with ecological and oceanographic models.
- Full Text:
- Date Issued: 2019
An Integrated Management System to reduce False Codling Moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) infested citrus fruit from being packed for export
- Authors: Mac Aleer, Clint
- Date: 2019
- Subjects: Cryptophlebia leucotreta -- South Africa , Cryptophlebia leucotreta -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Insect pests -- Biological control -- South Africa , Insecticides , Citrus fruit industry -- South Africa , South Africa -- Commerce -- European Economic Community Countries
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92219 , vital:30691
- Description: False codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is indigenous to southern Africa and is an important pest of citrus in this region. As a result of its endemism to sub-Saharan Africa, several countries to which South Africa exports citrus, regulate it as a phytosanitary pest. Consequently, it is necessary to ship fruit to these markets under cold-disinfestation protocols. This has been possible, as until recently, all of these markets could be considered relatively small niche markets. The South African citrus industry exports approximately 130 million cartons of fruit (15 kg equivalent) annually. During the 2017 season, a total of 48 million cartons were exported to the European Union (EU), which is the equivalent of 41% of South Africa’s total export volume, thus making the EU South Africa’s most important export market. In 2013 the European and Mediterranean Plant Protection Organisation (EPPO) conducted a pest risk analysis (PRA) on FCM, leading to the EU declaring it an officially regulated pest for this region, effective of 1 January 2018. Citrus is regarded as a preferred non-native host of FCM and South African citrus was identified as a primary focus due to large volumes being exported to Europe. Shipping under cold disinfestation is not possible with such large volumes of fruit. Additionally, several cultivars would suffer high levels of chilling injury under such conditions. In this study, an Integrated Management System was tested with pre- and postharvest controls to test the hypothesis that pre-harvest interventions resulted in lower post-harvest infection. Thirty orchards ranging from soft citrus cultivars such as Nule and Nova Mandarins, to Navel orange cultivars such as Newhall, Palmer and Late Navel and ending with Valencia cultivars such as Midknight and Delta, were identified for this study. This system relies on pre-harvest inspections such as FCM trap counts and fruit infestation on data trees in every orchard, with associated thresholds for action or continued compliance. Inspections were conducted on a weekly basis. There was a significant relationship between the moth catches and FCM infestation for the full monitoring period, using a two-week lag period for infestation. Inspections of harvested fruit were conducted at the packhouse to determine FCM infestation. This included inspection of the fruit on delivery to the packhouse, on the packing line, and a final fruit sample taken from the packed product and inspected for FCM. The highest levels of infestation were recorded on the Navel cultivars, thus confirming that Navels cultivars are a preferred host for FCM. Significant positive relationships were recorded between FCM infestation during the last 4 weeks before harvest and the level of infestation in the fruit delivered to the packhouse and between the fruit delivered to the packhouse and in the fruit packed in a carton for export. There was a substantial reduction in infestation between the fruit delivered to the packhouse and the fruit packed in a carton for export, with certain orchards recording as much as a 93% reduction in the fruit packed in a carton, which indicated that the packhouse could effectively identify and remove FCM infested fruit. The outcome of the study is that a holistic management approach minimizes the risk of FCM in citrus fruit destined for export and therefore mitigate the risk associated with FCM.
- Full Text:
- Date Issued: 2019
An intracategorical intersectional framework for understanding ‘supportability’ in womxn’s narratives of their pregnancy
- Authors: Kalyanaraman, Yamini
- Date: 2019
- Subjects: Pregnancy -- Psychological aspects -- South Africa , Prenatal care -- South Africa , Pregnant women -- South Africa -- Psycology , Medical care -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/96647 , vital:31304
- Description: In South Africa, the current Maternal Mortality Ratio (MMR) is 135 per 100,000 live births, with a long way to go before it can achieve the Sustainable Development Goal (SDG) global target of under 70 per 100,000 live births by 2030. This research project focuses on the narratives of pregnant womxn in the Eastern Cape Province, using an intracategorical intersectional framework and Macleod’s ‘supportability’ model as a base. The study aims to locate womxn’s pregnancies within the interweaving biological, psychological, social, economic, cultural and political contexts within which they occur, while focusing specifically on the aspect of ‘supportability’. Through purposive sampling and snowballing methods, the research team recruited participants who were 18 years and older, in or past the second trimester of their pregnancy, and able to access antenatal care. Research data were produced using photo-elicitation techniques on 92 photographs and narratives from 32 interviews. An intersectional thematic analysis was used to generate themes, which highlighted different aspects that enabled or hindered pregnancy ‘supportability’. In accordance with prior research, it was revealed that womxn found emotional and tangible support the most beneficial. Findings from this study reveal the interconnectedness between a womxn’s personal (emotional, physical and cognitive) experiences of pregnancy, the micro-interactions of support (un)available from partners, family, friends, healthcare workers, workplaces and community members, and the macrostructures of socioeconomic policies, religiosity, cultural practices and healthcare systems. For example, gendered perceptions (a macro-structure) influence the instrumental support provided by partners (a micro-interaction), which impacts the womxn’s well-being (personal). Certain themes that emerged from the different narratives were: the importance of making available pregnancy-related information to the womxn; a desire for non-judgement and acceptance of their pregnancies within their community; and the need for adequate communication in microinteractions. The findings of this research also indicate that, despite the financial tensions inherent in each womxn’s life, the participants were driven by overarching hopes for their child’s future.
- Full Text:
- Date Issued: 2019
An investigation into amaXhosa new initiates’ masculine identity construction, mediation and negotiation: implications for the Life Orientation Curriculum
- Authors: Mdaka, Sizwe
- Date: 2019
- Subjects: Xhosa (African people) -- Rites and ceremonies , Xhosa (African people) -- Social life and customs , Initiation rites -- South Africa -- Eastern Cape , Masculinity -- South Africa -- Eastern Cape , Life skills -- Study and teaching -- South Africa -- Eastern Cape -- Case studies , Life skills -- Study and teaching -- South Africa -- Curricula , Men -- Identity -- South Africa , Boys -- Education -- South Africa , Gender identity in education -- South Africa
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/94926 , vital:31097
- Description: This study asked questions about dominant discourses shaping new amaXhosa initiates masculine identities. In particular, it asked questions on the interface between tradition and modern values and how the new initiates negotiate these in constructing masculine identities and the implications this has for schooling (and specifically LO classes). This was a qualitative case study that relied on multiple sources of data including individual and focus groups interview with AmaXhosa new initiates as well as individual interviews with teachers. The study also included classroom observations of Life Orientation classes as the selected schools. Initially, informal discussions with the new initiates were held to gain insights on their perspective of initiation schools. The findings of this study revealed three broad themes. The first was that normative masculine conceptions and manhood, with particular attention paid to constructions of manhood and masculine identity and their relation to emotional display, men as breadwinners and family providers, marriage, and heterosexuality and fatherhood. The second one was on gender space and power in the classroom which revealed masculine performance inside and outside the classroom, and the role played by sitting positions and spatial arrangements as a discursive spaces for the construction of particular masculine identities. The third related the curriculum in practice versus the stated LO curriculum and revealed a disjuncture between the two. With teachers tolerating the traditional male structures and behaviours in the classroom, despite being in conflict with the stated LO curriculum core messages on gender, patriarchy and equality, intentionally or unintentionally select a position of collusion rather than disruption of these classroom behaviours. The study results highlight the complex social space that new initiates inhabit in order to make meaning of their masculine identities, and the challenges for teachers and schools in mediating between the traditional values and behaviours of some leaners, some of which are in conflict with the values and behaviours espoused by the LO curriculum and the modernizing project goals of SA education and the Constitution.
- Full Text:
- Date Issued: 2019
An investigation into the interaction partners of the scaffold protein human CNK1 in the NF-κB pathway
- Authors: Moodley, Holisha
- Date: 2019
- Subjects: CNK1 , Scaffold proteins
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/96031 , vital:31228
- Description: The protein connector enhancer of KSR1 (CNK1) plays a role in a number of signalling pathways including those involved in cell proliferation, cell growth and differentiation. De-regulation of these pathways has been linked to the promotion of oncogenic signalling. The involvement of CNK1 in all of these diverse pathways indicates a need to better understand the role of this protein within the cell and within key signalling networks. The research provides a platform to understand the intricate relationships that occur between these key signalling networks with the potential to identify new drug targets. CNK1 is multifunctional scaffolding protein that has binding domains that mediate and co-ordinate signalling within the MAPK, Hippo, PI3K/AKT, JNK and NF-κB pathways as well as downstream of the AT2 receptor. The activity of CNK1 is regulated through its interactions with a range of different binding partners within these pathways. Of particular interest to this research is the role of CNK1 in NF-κB signalling. The deregulation of the NF-κB pathway is implicated in chronic inflammation, tissue damage and induction of cervical and breast cancer. CNK1 has been reported to regulate the non-canonical branch of the NF-κB pathway, upstream of the IKK complex however new findings lead to uncertainty about these conclusions. In addition, the interacting partner of CNK1 in the NF-κB pathway has not been elucidated. In this thesis, we aim to identify the binding partners of CNK1 in the NF-κB pathway. First, we validate an epitope-tagged CNK1-expression construct to express elevated levels of CNK1 in cervical cancer cells. We report that the expression of myc-CNK1 is comparable to endogenous CNK1. Cells expressing elevated CNK1 levels were used in traditional co-immunoprecipitation reactions to identify potential CNK1-interacting proteins. We present data that indicates a potential role for NIK in the CNK1 signalling complex. We discuss the weaknesses of the traditional co-immunoprecipitation reactions and design an alternative co-immunoprecipitation technique with which to study CNK1-interacting partners. In this system, a promiscuous biotin ligase fused to the protein sequence for CNK1 (BirA-CNK1) is used to label proteins proximal to CNK1 with biotin. Using this BirA- CNK1-expressing construct in cervical cancer cells, we demonstrate that CNK1 interacts with IKKα-IKKβ in the NF-κB pathway.
- Full Text:
- Date Issued: 2019
An investigation into the performance of smallholder irrigation schemes in Limpopo Province, South Africa: success factors, typologies and implications for development
- Authors: Denison, Jonathan Anthony Noel
- Date: 2019
- Subjects: Irrigation projects -- South Africa -- Limpopo , Farms, Small -- South Africa -- Limpopo , Land use -- South Africa -- Limpopo , Water-supply -- South Africa -- Limpopo
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92317 , vital:30709
- Description: The research aimed to determine the factors that contribute to the success or failure of smallholder irrigation schemes in the Limpopo Province. It focussed on public-schemes where farmers share the water system Limpopo Province has more than half of the smallholder irrigation schemes in the country with an equipped area of approximately 28 000 ha. The main aims of the research were to identify key factors that explain performance and to develop a contemporary irrigation scheme typology. The research intended to provide a better perspective on how to focus investments across the multiple thematic areas that are associated with sustained and profitable irrigation farming activity. A survey of 102 irrigation schemes was conducted, comprising 82% of the population of schemes greater than 20 ha in Limpopo Province. The quantitative survey complemented prior in-depth qualitative research undertaken on Limpopo schemes. Data was consolidated into five performance indicators and 13 characteristic factors that impact performance. Schemes were viewed as technical and socio-biological systems where performance was determined by the dynamic interaction of multiple factors. The analysis was done in a complex systems framework using correlation, cluster and principle component analysis. It was postulated that over-arching concepts of productivity, profitability and manageability would explain why schemes succeed or fail. The schemes were found to be relatively very small in size with three quarters (74.8%) of them falling in the 50 to 250 ha size range, and only 11 schemes larger than 250 ha. Average plot sizes were 1.34 ha with a wide range between 0.18 and 16.25 ha. There were 65 operational schemes (equivalent to 63.7%), and 37 had failed (equivalent to 36.3%). Using a criterion for success of greater than 50% cropping intensity (to align with other studies and below which schemes can be considered to have failed), the success rate of the Limpopo schemes was 58%. The result was similar to the rest of South Africa and the same as the average rate for SADC identified in other studies using the same criterion. The schemes exhibited a mixed production purpose on average, with a significant market emphasis indicating these schemes have largely evolved from ‘food schemes’ to partly market-farming. Main crops grown were summer-maize and winter fresh-vegetables and cropping intensities on operational schemes ranged widely from 10% to 175%, with an average of 94%. Failure was associated with three dominant factors: energy type; infrastructure condition; and water resource constraints. The first two factors showed that manageability of technology was important. There is strong empirical evidence that pumped smallholder schemes are vulnerable in their physical form, prone to functional and financial failure, live much shorter lives, and perform no better than gravity-canal schemes. Out of the 37 schemes that failed, 34 (91.8%) were pumped. Pumped schemes tend to collapse suddenly while young and exhibit lower cut-off thresholds in productivity that, when crossed, trigger collapse. They also have much lower resilience to factors such as water stress or low farm-profitability. Pumped schemes need higher levels farm sophistication, market-oriented farming, and operational capability to keep the pumping pressure up. Water resource constraints were widespread, considerably more so on gravity schemes. Commercialising farmers were inhibited by lack of access to knowledge. Success was associated with numerous factors, but two findings stand out; the performance of gravity systems and the prevalence of land-exchange activity; the latter enabled by institutional flexibility and reflecting a process of ‘bricolage’ at play. Increased plot size was associated with increased commercialisation and, when larger than 1.8 ha, only commercialised farming was pursued. Market proximity seemed to play a role in increased longevity and to market access in commercialisation. These findings highlighted the importance of productivity and profitability in explaining success. Gravity schemes performed much more strongly in terms of longevity (nearly four times longer-lived) and similarly to pumped schemes in terms of cropping intensity. This was achieved under much greater water stress and with considerably worse infrastructure condition. Water efficiency was determined to be high on half of the schemes that were using short-furrow irrigation; equivalent, in a basin perspective, to drip irrigation. Two of the three top performing schemes (>150% intensity) were old gravity schemes. Farmers on approximately 75% of Limpopo smallholder schemes are currently engaging in land exchange transactions in a highly insecure and un-formalised institutional setup. Land exchange prevalence longer than two years was moderately associated with cropping intensity and strongly associated with commercialisation. This result has three important implications. First, it suggests that more land is utilised on the schemes when there is vibrant land-leasing activity. Secondly, schemes with a higher prevalence of long-term leasing seem to have a strong tendency to be more commercialised. Thirdly, the duration of the lease is significant, as neither single-season, nor annual leases yielded any positive associations, while those exchanges that were two years or longer, were associated with increased performance. These findings highlight the potential for longer-term land-exchange interventions to address the widespread low land utilisation on smallholder schemes, and to catalyse more commercially-oriented farming. An irrigation scheme typology was derived from the cluster analysis and was aligned to a contemporary irrigation farming typology. The key descriptors included technology type, purpose of farming and scheme management type. By matching scheme type to the farmer typology (or typologies), strategic decisions regarding technology choices for infrastructure, land, and water institutional interventions can be better informed. All schemes demand attention to the multiple factors required to achieve performance, not least water-tenure security, irrigation management organisational development, and infrastructure modernisation. Complexity was demonstrated by the finding that multiple factors contribute to success, and that there are many dimensions that change independently and have a cascading effect through the system in ways that are difficult to predict. Agricultural systems support to achieve productivity and profitability are essential for success. The research findings lead to the recommendation that, in addition, strategic planners must also consider the implications of the dominant factors of water-technology choices so that these are manageable, and the dynamics of farm-size change based on land exchange processes, in order to harness new opportunities to maximise irrigation scheme performance in future.
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- Date Issued: 2019
An investigation of learning and emerging knowledge in the Mpophomeni Sanitation Education Project, Howick, KwaZulu-Natal
- Authors: Boothway, Reinetta Louina
- Date: 2019
- Subjects: Environmental education -- South Africa , Mpophomeni Sanitation Education Project (South Africa) , Water quality management -- Study and teaching -- South Africa , Knowledge and learning
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/115377 , vital:34121
- Description: This study took place within the broader context of water resources management in South Africa. With the democratisation of water stewardship through an enabling international and South African water policy landscape, an opportunity opened up for citizens to participate in the effective management of their own water resources. In this context, a community-engaged citizen science project known as the Mpophomeni Sanitation Education Project emerged to demonstrate how a diverse range of knowledge agents can work and learn together to better manage their water resources and address problems of sewage pollution threatening their provincial water source. The following study aimed to shed light on the learning and emerging knowledge in the MSEP. The study was conducted in three phases. Wenger’s Communities of Practice (CoP) theory provided a lens to look at Phase One, which aimed to answer the following sub-question: Is the MSEP a CoP? Wenger’s CoP theory also assisted with the investigation during Phase Two, which looked at the following question: What is the nature of learning in the MSEP? Social realist theories of knowledge and education, and Tàbara and Chabay with their Ideal Type (IT) worldviews, provided suitable lenses for Phase Three’s investigation of the following question: What is the nature of emerging knowledge in the MSEP? The main finding for Phase One is that the MSEP does function as a CoP. With its strong focus on relationships, it’s clearly defined joint enterprise of solving the problem of sewage pollution, individual and joint commitment to engage with the problem and the sharing of a repertoire of tools, ideas and practices it is cultivating a culture conducive to purposeful learning. Regarding the exploration of the nature of learning in Phase Two, findings confirming the engagement of identity with learning and the importance of context for meaning-making emerged. Finally, study findings about the nature of knowledge in the MSEP found that the knowledge practices in the MSEP that are both social and epistemic in nature are produced by a diverse range of knowledge agents in an open knowledge space.
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- Date Issued: 2019
An investigation of the security of passwords derived from African languages
- Authors: Sishi, Sibusiso Teboho
- Date: 2019
- Subjects: Computers -- Access control -- Passwords , Computer users -- Attitudes , Internet -- Access control , Internet -- Security measures , Internet -- Management , Data protection
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163273 , vital:41024
- Description: Password authentication has become ubiquitous in the cyber age. To-date, there have been several studies on country based passwords by authors who studied, amongst others, English, Finnish, Italian and Chinese based passwords. However, there has been a lack of focused study on the type of passwords that are being created in Africa and whether there are benefits in creating passwords in an African language. For this research, password databases containing LAN Manager (LM) and NT LAN Manager (NTLM) hashes extracted from South African organisations in a variety of sectors in the economy, were obtained to gain an understanding of user behaviour in creating passwords. Analysis of the passwords obtained from these hashes (using several cracking methods) showed that many organisational passwords are based on the English language. This is understandable considering that the business language in South Africa is English even though South Africa has 11 official languages. African language based passwords were derived from known English weak passwords and some of the passwords were appended with numbers and special characters. The African based passwords created using eight Southern African languages were then uploaded to the Internet to test the security around using passwords based on African languages. Since most of the passwords were able to be cracked by third party researchers, we conclude that any password that is derived from known weak English words marked no improvement in the security of a password written in an African language, especially the more widely spoken languages, namely, isiZulu, isiXhosa and Setswana.
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- Date Issued: 2019
An investigation of the teaching of writing in Grade-9 English first-language classrooms: a case study of a selected government school in Namibia
- Authors: Martins, Simone Alexandra Domingues
- Date: 2019
- Subjects: English language -- Rhetoric -- Study and teaching -- Namibia , English language -- Study and teaching (Secondary) -- Namibia , English language == Composition and exercises -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/92280 , vital:30699
- Description: The pedagogical practice choices teachers make when teaching writing in Grade-9 English first- language classrooms, as well as the extent to which these pedagogical practices appear to enable or constrain learners’ acquisition of writing skills as per grade-specific curricular expectations, are the focus of the study. It draws from Bernstein’s (1971) curriculum and society theory, as well as genre theory. Located within the qualitative case study approach, it is designed to investigate the reasons for Grade-9 English first-language learners’ underperformance in Paper 2, the composition component of the Namibian external examinations. Drawing from the interpretivist paradigm, the study uses one-on-one interviews, semi-structured classroom observations, as well as documentary evidence of the Namibian English first-language syllabus and examples of learners’ written work, to generate data. The research site and study participants were purposefully selected. The study involves two Grade-9 English first-language teachers and classrooms at one Namibian High School, and took place from the second to the third terms of 2017.
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- Date Issued: 2019
An oversimplification of physiological principles leads to flawed macroecological analyses
- Authors: Boyles, Justin G , Levesque, Danielle L , Nowack, Julia , Wojciechowski, Michal S , Stawski, Clare , Fuller, Andrea , Smit, Ben , Tattersall, Glenn J
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440505 , vital:73788 , https://doi.org/10.1002/ece3.5721
- Description: In light of the rapidly changing climate, there is an urgent need to develop a mechanistic understanding of how physiological functioning mediates ecological patterns. Recently, there has been a spate of papers using analyses that scale up from a standard physiological model, the Scholander–Irving model, to make predictions about range constraints on endothermic vertebrates (Buckley, Khaliq, Swanson, and Hof, 2018; Fristoe et al., 2015; Khaliq, Böhning‐Gaese, Prinzinger, Pfenninger, and Hof, 2017; Khaliq, Hof, Prinzinger, Böhning‐Gaese, and Pfenninger, 2014). Here, we argue that oversimplifications of the Scholander–Irving model and the use of questionable datasets lead to questionable macrophysiological analyses. Many of these problems have been addressed elsewhere, directly and indirectly (eg, McKechnie, Coe, Gerson, and Wolf, 2017; Mitchell et al., 2018), although the focus has largely been on the applicability of the Scholander–Irving model to warm environmental temperatures, which are often seen as more relevant to climate change. However, one specific aspect of the Scholander–Irving model, the assumption that energy expenditure of an endotherm below the thermoneutral zone (TNZ) can be described by basic Newtonian physics, has been used incorrectly in several papers. While not the only paper based on this assumption, the recent work by Buckley et al.(2018) reinvigorated discussions among physiologists about improper interpretations of the Scholander–Irving model. Our concerns are not new and have been voiced repeatedly in the past (Calder and Schmidt‐Nielsen, 1967; King, 1964; Tracy, 1972), but many of these ideas seem to have been buried by time.
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- Date Issued: 2019