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Effect of bromination on the optical limiting properties at 532 nm of BODIPY dyes with p-benzyloxystyryl groups at the 3, 5-positions

  • Authors: Ngoy, Bokolombe P , May, Aviwe K , Mack, John , Nyokong, Tebello
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/187507 , vital:44665 , xlink:href="https://doi.org/10.1016/j.molstruc.2018.08.012"
  • Description: The optical limiting (OL) properties of 3,5-di-p-benzyloxystyrylBODIPY dyes that contain both protons and bromine atoms at the 2,6-positions have been investigated by using the Z-scan technique at 532 nm on the nanosecond timescale. There is relatively weak absorbance at 532 nm under ambient light conditions, because the incorporation of p-benzyloxystyryl groups at the 3,5-positions results in a ca. 140 nm red shift of the main BODIPY spectral band to the 640–670 nm range. Reverse saturable absorbance (RSA) profiles that are consistent with an excited state absorption (ESA) mechanism involving the T1 and/or S1 states are observed in CH2Cl2 solution. Second order hyperpolarizability values of ca. 8 × 10−30 esu are obtained and this demonstrates that the dyes are potentially suitable for use in OL applications at 532 nm. There is a slight enhancement of the OL properties upon bromination, due to increased intersystem crossing to the triplet manifold, but the enhancement of the OL properties is less significant than has been observed with metal phthalocyanine complexes.
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  • Date Issued: 2019

Ecological assessment and biogeography of coastal vegetation and flora in southern Mozambique

  • Authors: Massingue, Alice Obed
  • Date: 2019
  • Subjects: Coastal plants -- Mozambique , Coastal plants Marine biodiversity -- Mozambique Coastal biodiversity -- Mozambique
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/40988 , vital:36280
  • Description: This study considered aspects of the vegetation of the coastal zone of southern Mozambique, an area with a rich biodiversity. The vegetation and flora were assessed in their current state including the associated anthropogenic pressures. The environmental conditions that determined the distribution of the vegetation were evaluated. A hierarchical classification, description and ecological interpretation of the vegetation and flora of the coastal zone in southern Mozambique are presented. Analysis was based on 242 sample quadrats that were distributed in a stratified manner throughout the study area. The vegetation could be grouped into six distinct types of vegetation: Dune Forest, Coastal Forest, Coastal Grassland, Coastal Miombo, Coastal Savanna and Coastal Woodland. Species diversity was high for the all the vegetation types, particularly in the woody elements. A total of 673 species in 410 genera was recorded. They represented 104 families with Fabaceae and Rubiaceae being the most common. Of these, 6.6% were endemic or near-endemic to the coastal zone of southern Mozambique with Coastal Forest being the habitat with the greatest endemism. All soils from different vegetation types had poor agricultural potential. Soil properties were the strongest defining environmental feature separating the vegetation types: e.g. pH was high in Dune Forest compared to the others. Results from Maxent modelling suggest that the distribution of endemic species is influenced by a combination of climatic and non-climatic variables. Soil type, temperature annual range and precipitation of the driest month were the most important predictor variables. Overlaying the potential distributions of the seven selected species indicated two areas of abundance of endemic species – these should be given attention for conservation. Endemic species are not well protected in southern Mozambique – their sampled and potential habitats are largely outside protected areas. Hence, additional reserves should be created to improve their protection. Most endemic and near-endemics species were found in the south, from Ponta de Ouro (Matutuine, south of Maputo Province) to Manhica district (north of the Maputo Province) forming part of the Maputaland Centre of Endemism. A second concentration of endemism was found in the Inhambane Province, specifically the Inhassoro and Vilanculos districts. This is proposed to be an Important Plants Area (IPA). Because most endemics and near-endemics are found in the Coastal Forest, their main threat is harvesting for charcoal production, although none of the endemic species are specifically targeted for charcoal production. In Inhambane they are also threatened by the tourism industry, agriculture and settlements. The impact of the habitat destruction on endemic species is expected to cause severe declines in the near future. The tourism industry and harvesting of trees for charcoal production and over-frequent fires are the main drivers of vegetation loss in this region. Shifting agriculture, harvesting for firewood and construction materials, cattle grazing (at a minor scale) are also impacts, but these were only observed in a small area of Maputo Province. Although the study was done in coastal zone of southern Mozambique, effective management of whole coastal zone of the country will be required to maintain a functioning and diverse ecosystem. Priorities for management are to ensure that forests are protected, in particular, Dune Forest. Actions are required to minimise degradation of coastal vegetation. Further research on Coastal Forest restoration should be planned, as field observations in this study confirm that forest in the coastal zone of southern Mozambique has resilience.
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  • Date Issued: 2019

Incentive effects: assessing effort and heterogeneity in professional tennis

  • Authors: Chadwick, Byron James Rhett
  • Date: 2019
  • Subjects: Professional sports -- Economic aspects , Tennis players -- Wages , Tennis -- Tournaments , Achievement motivation , Incentive awards
  • Language: English
  • Type: text , Thesis , Masters , MCom
  • Identifier: http://hdl.handle.net/10962/69467 , vital:29541
  • Description: This study explores the impact incentive effects have on the level of effort exerted by professional men and women tennis players. Understanding what impact incentives have on tennis players can allow for greater understanding of the impact incentives have in the workplace and how employees react to different incentive schemes. The study makes use of data from both the ATP and WTA tour of every tournament played during the 2016 season. This includes player statistics, tournament statistics and in-game statistics from the quarter-finals, semi-finals and finals of each tournament in an attempt to account for initial seeding effects. This provides a total of 440 ATP matches and 389 WTA matches for an overall sample size of 829 professional tennis matches. The findings from this study illustrate in the last three rounds of all the tournaments played, for both male and females, money is not considered to be a key motivator for players. The ATP and WTA results suggest that competitors do not alter their effort levels depending on the level of the tournament. This illustrates that players exert similar effort levels regardless of the amount of money or ranking points available. The outcome of the findings supports that of the capability effect of heterogeneity on players’ performance. This means that the outcome of a match is linked more to the abilities of the competitors involved as opposed to the incentives available. Thus, players will adjust their effort levels according to their opponent and not because there are more money or ranking points available. This suggests that both the ATP and WTA should aim to reduce the differences in abilities amongst the players in an attempt to raise the attractiveness of the sport. Overall, the findings from this study illustrate that the capability effect outweighs that of the incentive effect.
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  • Date Issued: 2019

Catholic and charismatic: identity construction in a catholic charismatic movement in Nigeria

  • Authors: Torty, Livinus
  • Date: 2019
  • Subjects: Catholic Church -- Nigeria , Pentecostalism -- Catholic Church Identity (Psychology) Identity (Psychology) -- Social aspects -- Nigeria
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/10948/43787 , vital:37047
  • Description: The Catholic Charismatic Renewal is a movement within the Catholic Church that blends and synthesizes elements of Catholicism and Pentecostalism. The movement straddles these two religious traditions within Christianity. Besides its incorporation of elements of Catholicism and Pentecostalism, the movement also has as its objective, the revitalizing and renewal of the Catholic Church through the power of the Holy Spirit. These fundamental orientations of the Catholic Charismatic Renewal distinguish it from other Catholic movements, bestowing on it its unique identity. Although different from other Catholic movements, the movement and its members lay claim to a Catholic identity and seek to assert its legitimacy within the Catholic Church. Existing literature has provided useful insights into the question of identity within the Catholic Charismatic Renewal. However, the question of identity construction within the movement has not been adequately and comprehensively addressed in academic literature. This is especially the case in the African context. This leaves therefore a gap in our knowledge of how the movement and its members construct their catholic and charismatic identities. This study sets out to explore how the movement and its members construct their identity in relation to the Holy Spirit, the institutional Catholic Church and other Catholics, as well as in the context of the movement’s ritual music. Identity construction in the Catholic Charismatic Renewal is seen as key to making meaning of the movement and its place within Catholicism. The study adopted a qualitative research and ethnographic approach in which empirical data was collected in the context of fieldwork through informal, semi-structured and focus group interviews as well as participant observation during the activities of a Catholic Charismatic prayer group in Minna, Nigeria. Theoretical perspectives drawn from identity, hermeneutics and anthropology of extraordinary experience were used as analytical lens in the study. The study revealed that identity within the Catholic Charismatic Renewal was constructed principally in relation to the Holy Spirit. A spiritual experience or encounter was central in such identity construction, and the subjective and intersubjective identity of the members revolved around the two key concepts of ‘spirit-centred identity’ and ‘empowerment’. The study indicated that the members of the movement constructed their identity in ways that demonstrated their loyalty to the Church and their status as an officially recognised Catholic movement. In addition, their identity was also constructed in relation to the functions that they perceived themselves to perform within the Catholic Church. Although the members of the movement considered their charismatic and catholic identities to be compatible, they understood themselves to be different from other Catholics. The study also showed that while music was considered to be important within the movement, the context and content of its ritual music were overwhelmingly Pentecostal, and music that projected a catholic identity was relegated to the background and given expression mainly in the realm of individual religious practice. The study suggests that identity construction within the Catholic Charismatic Renewal is multiple, ongoing, flexible, and sometimes contradictory and paradoxical. Through its identity construction, the members of the movement demonstrate the heterogeneity of the Catholic space and seek to extend the boundaries of Catholicism.
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  • Date Issued: 2019

Perspectives on land and water politics at Mushandike Irrigation Scheme, Masvingo, Zimbabwe

  • Authors: Mafukidze, Jonathan
  • Date: 2019
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/76479 , vital:30573
  • Description: Access to, control and ownership of land and water, amongst other natural resources in Zimbabwe, shape and affect rural lives, livelihoods, social relations and social organisation. Rural poverty has been entrenched and exacerbated by, amongst other factors, highly restricted access to these scarce resources. Historically, Zimbabwe’s rural areas (such as communal areas, smallholder irrigation schemes and resettlement areas) have existed as sites of struggles where contestations and negotiations over access to, control or ownership of these resources have taken place. Resultantly, multifaceted and dynamic social relations have been weaved and contested social spaces carved out. In rural Zimbabwe, contestations have tended to be complex, nuanced and intricate, working themselves out in different ways across time and space. In their heightened and more visible state, they have been characterised by violent physical expressions which, in the history of the country, involved two wars of liberation, the First Chimurenga (1896-1897) and the Second Chimurenga (1960s to 1980). The most recent violent manifestation was through nation-wide land invasions, politically christened the Third Chimurenga, which peaked in 2000 and continued sporadically to this day. Few studies on smallholder irrigation schemes in Zimbabwe have focused on understanding how contestations for access to scarce land and water resources are framed and negotiated at the local level. Cognisant of this lacuna, this thesis uses social constructionism in examining, as a case study, Mushandike Smallholder Irrigation Scheme in Masvingo Province in order to understand and analyse how land and water politics occur at the local level. The study deploys a qualitative research methodology approach in examining local water and land politics, which involved original irrigation beneficiaries and more recent land invaders. Findings of the thesis indicate that land and water shortages have increased considerably in the past two decades at the irrigation scheme due to the influx of land invaders into the scheme. This influx has had a negative impact on agricultural production and other livelihood strategies. Both scheme members and land invaders lay claim to land and water at Mushandike. These claims are intricately constructed and contested, and they are linked to broader issues such as partisan party-politics, policy developments, and tradition, origin, indigeneity and belonging. Though the struggles over land and water at Mushandike are firmly rooted in the concrete conditions of existence and experiences of beneficiaries and land invaders, external actors such as political leaders, state bureaucrats and traditional chiefs tend to complicate and intensify the contestations.
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  • Date Issued: 2019

An evaluation of the harmonised social cash transfer programme on livelihoods in Zimbabwe: the case of Mangwe District

  • Authors: Poseni ,Pedzisai
  • Date: 2019
  • Subjects: Economic development -- Social aspects Social integration Social systems
  • Language: English
  • Type: Thesis , Masters , MCom (Development Studies)
  • Identifier: http://hdl.handle.net/10353/13943 , vital:39730
  • Description: Poverty and limited livelihood options remains a huge challenge in Africa, particularly in Zimbabwe. The study investigated the effectiveness of the Harmonized Social Cash Transfer programme in improving household economy and strengthening livelihood options in Zimbabwe with a particular focus on Mangwe District. In order to come up with a comprehensive investigation, the researcher grounded the study in sustainable livelihood approach and the capabaility approach. Due to persistent poverty and people adopting precarious coping strategies in Zimbawe, the government and NGOs collectively came up with a comprehensive cash based poverty alleviation strategy to alleviate poverty and build on peoples livelihood options which is the cash transfer programme. The study utilized a qualitative methodology, based on its ability to provide a contextualized description of people’s perspectives, feelings and opinions in terms of how a programme affected them. The evaluation sought to find out whether the cash transfer programme achieved its objective of strengthening household economy. The study established that the Harmonized Social Cash Transfer programme made some positive inroad towards strengthening household economy, however, lack of stakeholders coordination, collapsed economy, pollitically motivated moves from the ruling party caused the programme to fail. As such, the poor Mangwe people are still continuing engaging in precarious coping strategies, such as, selling assets, eating less than one meal per day and venturing into prostitution. The study therefore, calls for the government to review the household size vs cash scale and regularly review the amount of money received to be in line with current prices of commodities
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  • Date Issued: 2019

Intersectionality and complexity in the representation of ‘queer’ sexualities and genders in African women’s short fiction

  • Authors: Du Preez, Jenny Boźena
  • Date: 2019
  • Subjects: Sexual minority culture , Sexual minorities' writings , African fiction -- Women authors -- History and criticism , Gender identity in literature , Short stories, South African , Feminism in literature , Political poetry , Eroticism in literature , Lesbianism in literature
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/119047 , vital:34697
  • Description: This thesis sets out to contribute to the growing body of knowledge about queer sexualities and genders in Africa by examining their depiction in selected post-2000 African women’s short fiction written in English. Post-2000, the short story form has become the primary vehicle for queer representations by African women writers, and is thus an important development in the burgeoning body of queer literature by African writers. Broadly speaking, this literary formation can be defined as anti-homophobic, feminist and politically pragmatic. Using an intersectional lens, this thesis sets out to examine four significant strands in the political work these stories engage in. The chapters are structured around four main points of contention that have particular significance at the intersection of ‘queer’, ‘women’ and ‘Africa’. Firstly, I examine South African short stories that perform what I call queer conversations with history: imaginatively asserting a queer South African history, writing back against a male-dominated and heterosexist literary canon and, in doing so, contributing to the reimagination of the contemporary South African nation. Secondly, I analyse short stories from Africa that foreground the family, both as social formation and ideology. I examine how these stories ‘fracture’ this powerful and naturalised heterosexist concept by depicting the tensions and contradictions that queer characters experience in relation to family. Thirdly, I consider short stories from various African contexts that work to reconceptualise queer sexuality in relation to religious discourse in order to challenge homophobic and patriarchal religious authority. Finally, I examine queer, feminist erotic short stories by African women writers that challenges various colonialist, racist, sexist and lesbophobic discourses that have historically stifled the portrayal of sex and erotic experience between women.
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  • Date Issued: 2019

Discorhabdin N, a South African Natural Compound, for Hsp72 and Hsc70 Allosteric Modulation: combined study of molecular modeling and dynamic residue network analysis

  • Authors: Amusengeri, Arnold , Tastan Bishop, Özlem
  • Date: 2019
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/162949 , vital:40999 , https://doi.org/10.3390/molecules24010188
  • Description: The human heat shock proteins (Hsps), predominantly Hsp72 and Hsp90, have been strongly implicated in various critical stages of oncogenesis and progression of human cancers. While drug development has extensively focused on Hsp90 as a potential anticancer target, much less effort has been put against Hsp72. This work investigated the therapeutic potential of Hsp72 and its constitutive isoform, Hsc70, via in silico-based screening against the South African Natural Compounds Database (SANCDB). A comparative modeling approach was used to obtain nearly full-length 3D structures of the closed conformation of Hsp72 and Hsc70 proteins. Molecular docking of SANCDB compounds identified one potential allosteric modulator, Discorhabdin N, binding to the allosteric β substrate binding domain (SBDβ) back pocket, with good binding affinities in both cases.
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  • Date Issued: 2019

Synthesis and photophysicochemical properties of novel axially di-substituted silicon (IV) phthalocyanines and their photodynamic antimicrobial chemotherapy (PACT) activity against Staphylococcus aureus

  • Authors: Sen, Pinar , Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186757 , vital:44531 , xlink:href="https://doi.org/10.1016/j.synthmet.2019.116203"
  • Description: In this study, novel silicon (IV) phthalocyanine axially di-substituted with benzimidazole moieties (3) and its quaternized derivative (4) have been synthesized and fully characterized. The photophysical and photochemical properties of both phthalocyanines such as absorption, fluorescence and, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions. These new silicon phthalocyanines exhibited low fluorescence but produced high singlet oxygen yields in both DMSO (compound 3 and 4) and aqueous media (compound 4). The quaternization of Si(IV)Pc (3) improved the triplet state quantum yield (ΦT) 0.61 to 0.83, consequently singlet oxygen generation (ΦΔ) increased to 0.69 from 0.42. Photodynamic antimicrobial chemotherapy activities (PACT) of Si(IV)Pc photosensitizers were determined towards Staphylococcus aureus. The higher efficiency was obtained with cationic derivative (4) giving reduction percentage value of 99.75%.
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  • Date Issued: 2019

Teachers’ engagement with learners in inclusive foundation phase classrooms: a case study analysis

  • Authors: Skae, Vera Astrid
  • Date: 2019
  • Subjects: Early childhood education -- South Africa -- Eastern Cape -- Case studies , Education and state -- South Africa
  • Language: English
  • Type: text , Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10962/92705 , vital:30722
  • Description: Since 2001, South African teachers have been attempting to practise inclusive education in classrooms in ordinary, public schools. Previous research has shown the many challenges South African teachers face in our current educational environment. Strong arguments, however, have been made for more research to be done on actual teacher engagement with learners in our ordinary, public school classrooms, and the extent to which classroom practices are inclusive (Engelbrecht, Nel, Nel & Tlale, 2015, p. 3). This study sought to do an in-depth critical analysis of three foundation phase teachers and their engagement with learners in their classrooms at an Eastern Cape school. The aim was to examine how inclusive education was being enacted by the teacher with learners in real classroom settings, with particular attention paid to ways in which learners experience barriers to learning. A micro-level analysis was conducted in a single unit case study and using a qualitative research approach in an interpretive paradigm. Questionnaires, observations, and semi-structured interviews were conducted in an attempt to gather in-depth data. It was heartening to observe the extent to which inclusive education and practices were being enacted at the school and in the classrooms, and instructive in providing examples of what can work in the South African context. Key findings of this study include the generation of a framework for analysing inclusive classroom practice at the micro level. Criteria were identified as indicators of inclusive education of learners including those experiencing barriers to learning in the classroom. This study builds on and extends what has been developed at the macro and micro level of inclusive education in schools and in the classroom. It found that a number of challenges remain for enabling the implementation of an inclusive education. At the macro level, these include the provision of clear directives for implementation of inclusive education by the appropriate authorities; the provision of well-structured professional teacher training and development programmes in inclusive classroom practices, as well as in barriers to learning and how to address them; and the provision of funding for school and classroom infrastructure and resources. At the micro level, these include the successful implementation by teachers of inclusive classroom practices and the provision of the necessary support for learners experiencing barriers to learning in their classrooms, including expert personnel, resources, and assistive devices.
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  • Date Issued: 2019

Retailers’ food waste management: challenges and potential for action in Port Elizabeth

  • Authors: Đào, Thị Anh Thư
  • Date: 2019
  • Subjects: Food industry and trade -- Waste minimization , Food industry and trade -- Waste disposal Refuse and refuse disposal
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/39359 , vital:35220
  • Description: Food waste management within retailers is seen as an important solution to assist retailers in effectively managing food waste, and by doing so improving food security while limiting negative ecological consequences. Given the lack of research attention focusing on the importance of managing food waste among South African food retailers, and in particular the Eastern Cape, the primary objective of this research was to investigate retailers‟ food waste management in Port Elizabeth. Primary data was collected by conducting interviews with representatives of Port-Elizabeth-based participating stores and their individual Head Offices. This treatise reports on the findings and the conclusions drawn.
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  • Date Issued: 2019

Local web news as tools for framing food security: the content analysis of four selected Eastern Cape web newspapers

  • Authors: Metula , Nolukhanyo Theorida
  • Date: 2019
  • Subjects: Food security World Wide Web
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10353/17484 , vital:41080
  • Description: This study evaluates how the Eastern Cape local web newspapers frame food security in the Eastern Cape Province. A qualitative content analysis by means of textual analysis was used to evaluate the selected local web newspaper’s content on food security related stories within the period of July-December 2017. The sample was drawn from four Eastern Cape local web newspapers- Daily Dispatch Live, Herald Live, Go and Express and The Talk of the Town. The analysis sought to determine how the selected local web newspapers frame food security concerning food availability, accessibility and affordability in the Eastern Cape Province. Additionally, the study aimed to ascertain the issues about food security that are raised by the Eastern Cape local web newspapers and, to establish the extent to which these Eastern Cape local web newspapers’ framing is helpful in ensuring participation, empowerment and community mobilization for food securing purposes. The results of this study indicate that the local web newspapers frame Eastern Cape Province as untapped food basket. The framing suggests that the Province can leverage its agricultural resources for job creation which will ensure economic growth and food security. The local web newspapers framing suggests that there are numerous channels such as natural food production, livestock production, smallholder farming that can enhance availability and access to affordable food to people in the Eastern Cape Province. The findings revealed that local web newspapers frame increased agricultural production as an important issue that demand serious and urgent attention of the Provincial government as it has the potential of not only ensuring food security but also impacting positively on the income of local farmers. The local web newspapers frame farm attacks, land redistribution and reinstatement as important factors that hinder food production and, ultimately, food security in the Eastern Cape v Province. Furthermore, this study discovered that the frame of references used by the local web newspapers, especially the emphasis on local farming, land redistribution and private sector help to empower and mobilize individuals and communities to participate in food security initiatives. This study concludes that Eastern Cape Local Web Newspapers can be veritable tools to enhance food security channels in the Eastern Cape Province
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  • Date Issued: 2019

Optical limiting and femtosecond pump-probe transient absorbance properties of a 3, 5-distyrylBODIPY dye

  • Authors: Ngoy, Bokolombe P , May, Aviwe K , Mack, John , Nyokong, Tebello
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186835 , vital:44538 , xlink:href="https://doi.org/10.3389/fchem.2019.00740"
  • Description: The optical limiting (OL) properties of a 3,5-di-p-benzyloxystyrylBODIPY dye with an p-acetamidophenyl moiety at the meso-position have been investigated by using the open-aperture Z-scan technique at 532 nm with 10 ns laser pulses. There is a ca. 140 nm red shift of the main spectral band to 644 nm relative to the corresponding BODIPY core dye, due to the incorporation of p-benzyloxystyryl groups at the 3,5-positions. As a result, there is relatively weak absorbance across most of the visible region under ambient light conditions. Analysis of the observed reverse saturable absorbance (RSA) profiles demonstrates that the dye is potentially suitable for use in optical limiting applications as has been reported previously for other 3,5-distyrylBODIPY dyes. Time-resolved transient absorption spectroscopy and kinetic studies with femtosecond and nanosecond scale laser pulses provide the first direct spectral evidence that excited state absorption (ESA) from the S1 state is responsible for the observed OL properties.
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  • Date Issued: 2019

A model for secure and usable passphrases for multilingual users

  • Authors: Maoneke, Pardon Blessings
  • Date: 2019
  • Subjects: Computers -- Access control -- Passwords Computer security
  • Language: English
  • Type: Thesis , Doctoral , PhD (Information Systems)
  • Identifier: http://hdl.handle.net/10353/12571 , vital:39289
  • Description: Research on more than 100 million passwords that have been leaked to the public domain has uncovered various security limitations associated with user-generated short passwords. Long passwords (passphrases) are considered an alternative solution that could provide a balance between security and usability. However, the literature shows a lack of consistency in the security and usability contributions of passphrases. For example, studies that investigated passphrase security focusing on structural dependencies at character level found passphrases to be secure. Inversely, other research findings suggest that passphrase security could be compromised by the use of predictable grammatical rules, popular words in a natural language and keyboard patterns. This is further exacerbated by research on passphrases that is focused on the Global North. This is a huge concern given that results from inter-cultural studies suggest that local languages do influence password structure and to some extent, password usability and security. To address these gaps in the literature, this study used socio-technical theory which emphasised both the social and technical aspects of the phenomenon under study. Psychological studies show that the memory has limited capacity, something that threatens password usability; hence, the need to utilise information that is already known during password generation. Socio-cultural theory suggests that the information that is already known by users is contextually informed, hence sociocultural theory was applied to understand the contextual factors that could be used to enhance passphrase security and usability. With reference to the Southern African context, this study argues that system designers should take advantage of a multilingual user group and encourage the generation of passphrases that are based on substrings from different languages. This study went on to promote the use of multilingual passphrases instead of emphasising multi-character class passwords. This study was guided by design science research. Participants were invited to take part in a short password and multilingual passphrase generation and recall experiment that was made available using a web-based application. These passwords were generated by participants under pre-specified conditions. Quantitative and qualitative data was gathered. The study findings showed the use of both African and Indo-European languages in multilingual passphrases and short passwords. English oriented passwords and substrings dominated the multilingual passphrase and short password corpora. In addition, some of the short passwords and substrings in the multilingual passphrase corpora were found among the most common passwords of 2016, 2017 and 2018. Usability tests showed that multilingual passphrases are usable, even though they were not easy to create and recall when compared to short passwords. A high rate of password reuse during short password generation by participants might have worked in favour of short passwords. Nonetheless, participants appear to reflect better usability with multilingual passphrases over time due to repeated use. Females struggled to recall short passwords and multilingual passphrases when compared to their male counterparts. Security tests using the Probabilistic Context-Free Grammar suggest that short passwords are weaker, with just more than 50% of the short passwords being guessed, while none 4 Final Submission of Thesis, Dissertation or Research Report/Project, Conference or Exam Paper of the multilingual passphrases were guessed. Further analysis showed that short passwords that were oriented towards an IndoEuropean language were more easily guessed than African language-oriented short passwords. As such, this study encourages orienting passwords towards African languages while the use of multilingual passphrases is expected to offer more security. The use of African languages and multilingual passphrases by a user group that is biased towards English-oriented passwords could enhance security by increasing the search space.
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  • Date Issued: 2019

Testing the efficient market hypothesis in the cryptocurrency market

  • Authors: Apopo, Natalya Camilla
  • Date: 2019
  • Subjects: Digital currency
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: http://hdl.handle.net/10948/42427 , vital:36662
  • Description: Digital currencies are rising in popularity owing to their purported benefits and the speculative profits that investors are making in the market. These currencies, though decentralised in substance, can be purchased using digital wallets from cryptocurrency exchange platforms around the world. In Africa, these platforms are still at the nascent stages of growth and development, but evidence suggests a burgeoning potential in these markets. Volatility in these markets has been a topic of concern for many empirical investigations with most finding corroborative evidence of excess volatility in the digital currency market. However, there is a conflicting body of evidence when it comes to the studies evaluating the efficiency of the virtual currency market. The efficient market hypothesis ( EMH)is a controversial theory in finance. Proponents argue that it provides a basis for understanding financial markets whereas opponents suggest that the hypothesis is premature in its assumptions of the real functioning of these markets. Though not perfect, the efficient markets model provides a sufficient baseline against which capital markets may be analysed. Besides being one of the most empirically investigated theories in finance, its utility led to the development of later models such as the capital asset pricing model. In postulating that the prices of securities reflect all available information in capital markets, the efficient markets theory lends itself to testing the efficacy levels of the cryptocurrency market. For the purposes of this study, the weak version of the efficient markets theory was evaluated as itis considered the lowest possible form of efficiency attainable. Using both linear and nonlinear unit root testing methodologies, a significant subset of the cryptocurrency market was investigated for inefficiencies via the null hypothesis of non-stationarity. There were mixed results from the testing process, but a substantial portion of the currencies investigated rejected the null of a unit root in favour of stationarity, providing some evidence against weak form efficiency. For these reasons, it is recommended that further research be conducted in the virtual currency markets to offer more conclusive findings.
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  • Date Issued: 2019

An analysis of the use of DNS for malicious payload distribution

  • Authors: Dube, Ishmael
  • Date: 2019
  • Subjects: Internet domain names , Computer networks -- Security measures , Computer security , Computer network protocols , Data protection
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/97531 , vital:31447
  • Description: The Domain Name System (DNS) protocol is a fundamental part of Internet activities that can be abused by cybercriminals to conduct malicious activities. Previous research has shown that cybercriminals use different methods, including the DNS protocol, to distribute malicious content, remain hidden and avoid detection from various technologies that are put in place to detect anomalies. This allows botnets and certain malware families to establish covert communication channels that can be used to send or receive data and also distribute malicious payloads using the DNS queries and responses. Cybercriminals use the DNS to breach highly protected networks, distribute malicious content, and exfiltrate sensitive information without being detected by security controls put in place by embedding certain strings in DNS packets. This research undertaking broadens this research field and fills in the existing research gap by extending the analysis of DNS being used as a payload distribution channel to detection of domains that are used to distribute different malicious payloads. This research undertaking analysed the use of the DNS in detecting domains and channels that are used for distributing malicious payloads. Passive DNS data which replicate DNS queries on name servers to detect anomalies in DNS queries was evaluated and analysed in order to detect malicious payloads. The research characterises the malicious payload distribution channels by analysing passive DNS traffic and modelling the DNS query and response patterns. The research found that it is possible to detect malicious payload distribution channels through the analysis of DNS TXT resource records.
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  • Date Issued: 2019

Experiences of undergraduate diagnostic radiography students regarding assessor feedback during summative clinical assessments

  • Authors: Hodgson, Hayley Dianne
  • Date: 2019
  • Subjects: Medical education , Teacher-student relationships Communication in education Mentoring in education Radiography, Medical -- Digital techniques
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: http://hdl.handle.net/10948/42296 , vital:36643
  • Description: Assessment and feedback are closely interlinked terms. High quality feedback within education and assessment can have a profound influence on learning. Summative clinical assessments and feedback, conducted in clinical training sites, are vital steps in successfully preparing an undergraduate diagnostic radiography student for the desired outcome of a competent, skilled diagnostic radiographer. Feedback has the potential to close the gap between a student’s actual clinical performance and desired clinical performance. Despite the importance of feedback, students across the globe, particularly in the health professions, are dissatisfied with the current feedback systems. Failure to provide effective feedback within the clinical context can be detrimental to patient safety because students have a false impression of their clinical skills and competencies. The aim of the study was to explore and describe the experiences of undergraduate diagnostic radiography students regarding assessor feedback during summative clinical assessments. A qualitative, exploratory, descriptive, and contextual research design was used to gain in-depth knowledge of the experiences of undergraduate diagnostic radiography students regarding assessor feedback during summative clinical assessments. Data were gathered from students by means of semi-structured focus group interviews. Data were transcribed verbatim and coded using Tesch’s eight steps. Two principle themes emerged from the data analysis. Theme 1 unpacked whether an assessor is an ally or foe. Theme 2 focussed on key elements that influence the nature of the feedback process. There were various positive experiences regarding assessor feedback during the summative clinical assessments reported by the participants. However, they were dissatisfied with numerous aspects of assessor feedback during their summative clinical assessments and this subsequently impeded their learning experience. Measures to ensure trustworthiness and ethical research practices governed this research study. Based on the findings, the recommendations include that the higher education institution, clinical supervisors, and radiography students, should utilise feedback as a learning tool for skills development during summative clinical assesssments.
  • Full Text:
  • Date Issued: 2019

Electrical, photo-thermal and mechanical degradation analysis of degraded single junction amorphous silicon solar modules

  • Authors: Osayemwenre, Gilbert Omorodion
  • Date: 2019
  • Subjects: Solar cells Amorphous semiconductors Silicon
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10353/15211 , vital:40204
  • Description: In this present era of sustainable energy development, photovoltaic modules which are based on amorphous silicon cells have immeasurable prospects of contributing meaningfully to the energy demand of the world at large. The global consciousness of environmental safety issues has birthed the rapid demand for the photovoltaic system. However, the production increase is mainly in bulk-type crystalline (c-Si) solar cells. Thus, to meet the high demand of the market, single junction amorphous silicon (a-Si:H) solar cells production must be encouraged through active research in that regard. This could also help to improve its efficiency and reliability. There has recently been a sharp decrease in the production cost of the bulk Si solar cell, but the a-Si:H solar cell still remains the most economically viable in comparison to the other PV technologies. Companies such as Sharp are currently developing large-scale a-Si:H solar modules that can produce an efficiency of 10.5% after the long-term degradation process. To date, a-Si:H is believed to be one of the most promising thin-film PV technologies (Saito et al., 1993; Hamakawa et al., 1994). The cost of a solar PV manufacturing fell by 6% in 2014 (Santa, 2014), this is in accordance with the 2008 cost production forecast; thus, the cost record stands at 0.20 per watt, as reported by the NPD Solar publisher. Amorphous silicon (a-Si) solar modules generate more kilowatt-hour (kWh) of electricity per kilowatt (kW) than crystalline silicon or other technologies of the same capacity of installation. Furthermore, a-Si:H modules have more functional hours per day. Single junction amorphous silicon (a-Si:H) modules can function beyond the peak sun hours, and they also have a better performance on a cloudy day. vii In other words, a 1kW PV system of a-Si:H is expected to generate more electricity per year in comparison to 1kW PV from other technologies, hence there is a low energy payback time. In this study, commercially available single junction amorphous silicon modules were bought from a local market and they were immediately deployed outdoors. The initial reading of the modules, which served as baseline reading, showed an average of 25% decrease in the modules performance, therefore, there is a need for a long term monitoring process to obtain the best and worst performing modules. Measuring the performance parameters of these PV modules under real sun light (IV) provides a better degradation assessment. This conventional assessment cannot provide an in-depth insight responsible for the variation and degradation of the performance parameters. More obscured parameters like recombination current and ideality factor were obtained from the dark IV measurements. However, this is still superficial in a way. The intrinsic parameters were obtained from scanning probe microscopy (SPM) and CV measurements. The study focuses on the degradation analysis of a-Si:H due to an increase in defect density. A rise in the defect concentration is a huge problem because it causes long-term solar cell degradation, which increases the recombination current and decreases the conversion efficiency. Furthermore, it decreases the photo-generating current and reduces the effective efficiency of the solar device. In other words, the electrical output decreases. This research investigates the reduction in a-Si:H modules’ maximum power, and correlates these with a hot spot formation. A PVPM IV tracer was used for the outdoor characterisation of the module’s temperature profile, while the IR camera was used to analyse the hot spot centre. A four probe IV/CV from NMU was used for the indoor assessment of smaller samples cleaved from both the affected and non-affected regions to characterise the electrical variations across the module viii samples. To be precise, in this study, a naturally degraded single junction amorphous silicon module was delaminated and its mechanical properties were analysed and correlated with the contact potential from a Kelvin probe force microscopy (KPFM).
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  • Date Issued: 2019

Improving public participation through ward based planning in Port St Johns Local Municipality

  • Authors: Koninga, Siyabonga
  • Date: 2019
  • Subjects: Political participation -- South Africa -- Eastern Cape , Social participation -- South Africa -- Eastern Cape Local government -- South Africa -- Eastern Cape Public Administration -- South Africa
  • Language: English
  • Type: Thesis , Masters , MPA
  • Identifier: http://hdl.handle.net/10948/45194 , vital:38262
  • Description: This research study deals with ways in which to improve public participation through ward based planning in Port St Johns local municipality. Public participation in South Africa is important, as it is the backbone of the democratic state that was introduced by the 1994 democratic elections. Public participation is essentially a process that engages communities from the planning phase to the implementation and evaluation phases of a particular activity or project. Public participation has become a key aspect of South African planning and is a recurring theme in several legislative and theoretical documents. Public participation is a principle that is accepted throughout all spheres of government. It is important because it is the only method whereby government can gain a sense of the needs and aspirations of the various communities. With specific reference to municipalities, public participation is enhanced through the establishment of ward based planning. The Port St Johns ward based planning process has not only been an opportunity for households and communities to contribute to the integrated development plan (IDP), it has also provided them with access to information. This is the first step towards re-skilling our people to participate in the knowledge economy. The ward based planning process provides a link between municipal level planning and delivery and activities at ward level. Port St Johns’ ward based planning process is the vehicle for entrenching participation in the IDP in order to maximise co-ordination and synergy between priorities and municipal programs. The main objective and aim of the study was to advance recommendations that may be adopted as solutions to Port St Johns’ municipal management for improving a strategy for the public to participate in municipal activities. In conclusion, this study found that community based planning does influence the municipality’s integrated development plan but its effectiveness lies in proper planning and giving it the attention it deserves as one of the tools to be used to improve public participation in the affairs of the Port St Johns Municipality.
  • Full Text:
  • Date Issued: 2019

Evaluating the benefits of the extended public works programme in the Buffalo City Metropolitan Municipality

  • Authors: Lindani-Beni, Bulelwa
  • Date: 2019
  • Subjects: Public service employment -- South Africa -- Eastern Cape , Community development -- South Africa -- Buffalo City Metropolitan Municipality Job creation -- South Africa -- Buffalo City Metropolitan Municipality Public works -- South Africa -- Buffalo City Metropolitan Municipality
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/40555 , vital:36182
  • Description: Public Works Programmes (PWPs) are interventions implemented by the government to overcome the high levels of unemployment and to provide the poor with salaries so that they can meet their basic needs. This was done in response to the United Nations (UN) call to meet the sustainable development goals adopted in 2015. The study defines PWPs and gives an overview of the categories of the intervention programmes. Different countries use the PWPs for different aims from poverty reduction, response to economic shocks and guaranteed employment. Most of the countries, like South Africa, use these programmes as a temporary relief. Unemployment remains a challenge in the Buffalo City Metropolitan Municipality (BCMM) and the municipality has always been unsuccessful in reaching the targets expected in job creation. The study compares the South African Extended Public Works Programme (EPWP) with the two other international programmes, India and Malawi. The analysis of the three phases of the South African EPWP since its inception in 2004 is done in this study. The paper analysed the BCMM’s EPWP projects in the Eastern Cape where there is a high level of unemployment and a high degree of rural-urban migration. An overview of the Malawi Social Action Fund (MASAF) and India’s National Rural Employment Guarantee Scheme (NREGA) is also presented in this study. The researcher analysed documents and desktop reviews for the study. The available information such as the programme strategic plans, logical frameworks, policy documents, implementation reports, academic journals and media reports were consulted for this study. The study highlighted challenges in the South African EPWP which contributes towards the inefficiency of the programme in reducing the high levels of unemployment in the BCMM. The researcher provided recommendations that may improve the effectiveness of the public works programme in South Africa. One recommendation is the development of a Management Information System for EPWP that can assist the government in monitoring and evaluating the whole programme in the different departments and municipalities.
  • Full Text:
  • Date Issued: 2019
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