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The taxonomy of the topminnows (Teleostei: Cyprinodontiformes) (Procatopodidae: Procatopodinae) of southern Africa

  • Authors: Van Zeeventer, Ryan Matthew
  • Date: 2020
  • Subjects: Cyprinodontiformes -- Africa, Southern , Killifishes -- Africa, Southern
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/145559 , vital:38449
  • Description: Taxonomy is a tool that plays a crucial role in the implementation of effective management assessments, the ability to identify different fish species and their life stages, and create effective conservation strategies. Recent years have seen an increase in the discovery of cryptic species which could have an effect on how we implement conservation strategies, increasing the importance of accurate taxonomic assessments. The southern African topminnows of the genera Micropanchax and Lacustricola (Family Procatopodidae) include several species of egg-laying fishes that live in the marginal areas of rivers and lakes throughout the river systems of southern Africa in separated and connected populations. It was recently discovered that these populations showed subtle differences in their morphology and colouration, which led to the belief that new and cryptic species may be present. Previous studies of the Procatopodidae relied heavily on phylogenetic analyses that drew on morphological traits without reliance on molecular methods of analysis. A few of the taxonomic issues were resolved through these limited studies but ultimately the taxonomic status of the Procatopodidae remained poorly understood. Furthermore, these studies had not been updated in recent years and hence the benefits of new technology had not been brought to bear on the issues. A multi-gene analysis using standard phylogenetic methods and five molecular markers (mitochondrial cytochrome C oxidase (COI), mitochondrial cytochrome b (cytb), mitochondrial 16S ribosomal RNA (16S rRNA), nuclear 28S ribosomal RNA (28S rRNA) and mitochondrial Tyrosine Kinase (X-src) (TyrK)) allowed phylogenetic trees to be made which demonstrated clear relationships within Micropanchax and Lacustricola of southern Africa and the out-groups used in the analysis. The inference trees showed that Micropanchax johnstoni was represented by three clades and was shown to be polyphyletic while Micropanchax hutereaui, which was represented by two clades, and Micropanchax katangae, which was represented by one clade, were monophyletic. The two species of Lacustricola, L. myaposae and L. macrurus showed very close relationships to Micropanchax and it is suggested that these two species be transferred to Micropanchax, leaving Lacustricola to only be found in central Africa.
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  • Date Issued: 2020

The Thousand-Pulsar-Array programme on MeerKAT–I: science objectives and first results

The Transformative Power of Language: From Postcolonial to Knowledge Societies in Africa

  • Authors: Kaschula, Russell H , Wolff, H Ekkehard
  • Date: 2020
  • Language: English
  • Type: text , book
  • Identifier: http://hdl.handle.net/10962/174514 , vital:42484 , ISBN 9781108498821
  • Description: Language has played a pivotal role in societal transformation in postcolonial Africa towards the creation of globally competitive knowledge societies; however so far, this role has been under-researched and under-estimated. This volume addresses this gap in the literature, by bringing together a team of globally-recognised scholars to explore the effect of language on African postcolonial societies, and how it has contributed to achieving 'mental decolonisation'. A range of languages are explored, both imported (ex-colonial) and indigenous African, and case studies from different spheres of public discourse are investigated, from universities to legal settings. Demonstrating that multilingualism is a resource for, rather than barrier to, successful transformation, this book brings the intellectualisation and institutionalisation of African languages to the forefront of development discourse, and provides an insightful snap-shot of how current academic research, public discourse, political activism and social community engagement have contributed to societal transformation in South Africa.
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  • Date Issued: 2020

The Unintended Consequences of Using Direct Incentives to Drive the Complex Task of Research Dissemination

  • Authors: Muthama, Evelyn , McKenna, Sioux
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/187116 , vital:44569 , xlink:href="https://doi.org/10.25159/1947-9417/6688"
  • Description: Universities have used an array of incentives to increase academic publications, which are highly rewarded in the South African higher education funding formula. While all universities use indirect incentives, such as linking promotion and probation to publication, the mechanisms used in some institutions have taken a very direct form, whereby authors are paid to publish. This process has paralleled a large rise in publication outputs alongside increased concerns about quality. Significantly, there are ethical questions to be asked when knowledge dissemination is so explicitly linked to financial reward through the payment of commission to academics. Based on an analysis of institutional policies and data from an online survey and interviews with academics from seven South African universities, we argue that when money is the main means used to encourage academics to contribute to knowledge, numerous unintended consequences may emerge. These include a focus on quantity rather than the quality of research, a rise in predatory publishing, and resentment among academics. We argue that incentives, in particular direct payment for publications, undermine the academic project by positioning publications in terms of exchange-value rather than their use-value as a contribution to knowledge building.
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  • Date Issued: 2020

The use of drawing to support teaching and learning of an additional language in foundation phase classrooms

  • Authors: Macubeni, Sandiswa
  • Date: 2020
  • Subjects: Language and languages -- Study and teaching -- Foreign speakers
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10948/49351 , vital:41676
  • Description: Parents in South Africa have been given the privilege and right to choose the language of learning and teaching (LoLT) for their children. However, because of the advantages associated with fluency in English, parents tend to choose English as the language of instruction, often without being informed as to the disadvantages of learning in an additional language. The use of an additional language as the main language of instruction can potentially negatively affect the academic performance of learners, as they are often unable to express themselves efficiently and comprehend instructions given in this additional language. In an effort to assist learners who may be struggling with learning in an additional language, this study explored the use of drawing to support the teaching and learning of an additional language in Foundation Phase classrooms. A qualitative approach was adopted in order to gain insights of Foundation Phase teachers regarding the use of drawing to promote the teaching and learning of English as an additional language. The methods that were used to elicit data in this study included focus groups, an open-ended questionnaire, field notes, reflective journal entries, and document analysis. The participants in this research were 18 Foundation Phase teachers from a school in the Northern Areas of Port Elizabeth. The collected data were analysed using thematic analysis. The findings of this study revealed that drawing is both an expressive and receptive visual language that has the potential to promote the teaching and learning of an additional language. However, for this additional language to be effective, teachers should create a stimulating environment and encourage learners to use this language in their classrooms. Teachers should also find creative ways to accommodate drawing within their planned teaching and learning activities in the classroom.
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  • Date Issued: 2020

The use of information and communication technologies in agricultural development in rural areas: case of smallholder farmers in Umzimvubu Local Municipality

  • Authors: Makaula, Zimasa
  • Date: 2020
  • Subjects: Agricultural extension work , Information technology , Farms, Small -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , M Agric (Agric Extension)
  • Identifier: http://hdl.handle.net/10353/11994 , vital:39125
  • Description: Proper and timeous communication amongst different social development participants is one of the main driving factors for successful human progress. Different platforms have been used by different industries across the globe to ensure that useful information is shared with relevant structures at appropriate times. The global increase on use and availability of Information Communication Technologies (ICT’s) has prompted a thorough analysis and study of their relevance on different industries. Much of the increase has been observed mainly on highly urbanized areas, where the majority of the population is literate and who are above the poverty line. Some researchers have argued that the language used in some of the ICT’s is limited to the elite few, while others highlight cost implications in the use of these ICTs. The agricultural industry is not immune to the debates that relate to the development of ICTs, it is in most cases at the center, due to its diverse nature (in terms of participation) and close linkage to human development. There seems to be a correlation between ICT usage and the economies of scale in agricultural development, where smallholder farmers tend to use less of highly modernized ICTs, while commercial large scale farmers use more of the modernized ICTs. This disparity amongst farmers is exacerbated in many areas by the differing support systems employed by the public extension services. This study was initiated in order to study the usage and relevance of the ICTs by the smallholder farmers of the Umzimvubu Local Municipality of the Eastern Cape Province in South Africa. The research address the following research questions: 1. Which ICTs are owned by smallholder farmers of Umzimvubu local municipality? 2. Do smallholder farmers use ICTs to communicate agricultural information? 3. What are the types of ICT devices and services used by smallholder farmers for vi agricultural development? 4. What are the challenges faced by smallholder farmers when using ICTs to communicate agricultural information? A survey questionnaire was then developed to collect the relevant data from randomly selected six villages of Umzimvubu Local Municipality. The questionnaires structure employed both closed and open-ended questions that were administered using a face to face interview, conducted on the sample population in each village. The results indicated that the most common ICTs that were owned by smallholder farmers in the study area were: mobile phones (33%), televisions (TV) (28%), and radio (20%). The results also showed that communication amongst farmers (35%) and extension officers (35%) was the most notable use of mobile phone from the study area. The results also revealed that most smallholder farmers faced the following challenges when using ICTs to retrieve agricultural information; poor signal (40%), inconsistent broadcasting times for TV and radio agricultural programmes (35%), language barrier (15%) and lack of electricity (10%). The study, therefore, concludes that a majority of smallholder farmers from the study area own ICT devices necessary for rural agricultural development (mobile phones, TV and radio) that can be targeted by extension officers, policy makers, rural development implementing agencies and agro-industries to promote rural development. However, several challenges (language barrier, poor network signal and no electricity) limit the potential of these ICT devices and services from fully benefiting smallholder farmers.
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  • Date Issued: 2020

The use of quantitative analysis and Hansen solubility parameter predictions for the selection of excipients for lipid nanocarriers to be loaded with water soluble and insoluble compounds

  • Authors: Makoni, Pedzisai A , Ranchhod, Janeeta , Khamanga, Sandile M , Walker, Roderick B
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/183376 , vital:43981 , xlink:href="https://doi.org/10.1016/j.jsps.2020.01.010"
  • Description: The aim of these studies was to determine the miscibility of different API with lipid excipients to predict drug loading and encapsulation properties for the production of solid lipid nanoparticles and nanostructured lipid carriers. Five API exhibiting different physicochemical characteristics, viz., clarithromycin, efavirenz, minocycline hydrochloride, mometasone furoate, and didanosine were used and six solid lipids in addition to four liquid lipids were investigated. Determination of solid and liquid lipids with the best solubilization potential for each API were performed using a traditional shake-flask method and/or a modification thereof. Hansen solubility parameters of the API and different solid and liquid lipids were estimated from their chemical structure using Hiroshi Yamamoto’s molecular breaking method of Hansen Solubility Parameters in Practice software. Experimental results were in close agreement with solubility parameter predictions for systems with ΔδT larger than 4.0 MPa1/2. A combination of Hansen solubility parameters with experimental drug-lipid miscibility tests can be successfully applied to predict lipids with the best solubilizing potential for different API prior to manufacture of solid lipid nanoparticles and nanostructured lipid carriers.
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  • Date Issued: 2020

The use of ritual as physical and spiritual medium and its documentation in Buhlebezwe Siwani’s contemporary visual arts performance

  • Authors: Lila, Philiswa
  • Date: 2020
  • Subjects: Arts and religion , Ritual -- South Africa , Performance art -- Religious aspects -- South Africa , Women performance artists -- South Africa , Siwani, Buhlebezwe, 1987-
  • Language: English
  • Type: text , Thesis , Masters , MFA
  • Identifier: http://hdl.handle.net/10962/166160 , vital:41334
  • Description: This thesis is motivated by my experience of Inzilo: Ngoba ngihlala kwabafileyo, a live performance by South African visual artist Buhlebezwe Siwani. The performance took place at Michaelis Galleries, University of Cape Town (UCT), as part of a group exhibition Between Subject and Object: human remains at the interface of art and science (2014), which accompanied the Medical Humanities in Africa Conference (from 28 – 29 August 2014). As an entry into my discussion, I describe how Siwani’s performance makes use of death and burial ritual in what seems to be an intention to make art that is (re)presenting an activity of reality to invade and control the sphere of feelings, emotions and a sense of ceremony that is dependent on both ritual and rites of the performance. I grapple with the fact that I experienced a ritual performance in a gallery space. Furthermore, I question how walking out of the performance I thought of the lines between art and/or life. The role of ritual in my thesis explores the symbolic meanings, powers and intentions of ritual rites in Africa. This reflection maps out historical locations that are relevant to the major debates, definitions, themes and the experiences of ritual as part of academic research. From Siwani’s practice as an artist and isangoma to other expressions in the fields of history, sociology, religion, feminism, to mention a few, my thesis is an enquiry that engages ritual and performance art theory and scholarship. Through a qualitative analysis, my methodology rejects a chronological, thematic and discipline centered research. Rather, I use a multidisciplinary approach based on critical visual analysis as knowledge creation in the visual arts, for example archives, documentation, performance, text, video, installation, painting, sculpture, etc. The findings suggests that the role of ritual in performance art is not a singular exploration, nor is it based on separating ritual and performance art. The results further reveal that ritual in performance art is not a reenactment of patterns and human behaviours, nor is the notion of reenactment used to denote the myriad meanings and functions of re-performing historical ritual events into performance art. Throughout, my thesis provides a focus that demonstrates the significance of how ritual in performance art has a profound subjective (personal or individual) and collective holistic way of serving human and spiritual needs, and that of creating an environment that is open to the content and context of art as it relates with traditional African religious practices, beliefs and knowledges. Focus is given to three major themes that make up the three chapters of my research: firstly, I reflect on death as personified by Siwani’s performance Inzilo: Ngoba ii ngihlala kwabafileyo and her role as isangoma. Here death is used to draw specific attention to the body in process of embodied presence and absence of physical and spiritual worlds. Secondly, drawing on Siwani’s concept of secrecy and boundaries of concealing and revealing rituals meanings and powers as isangoma, I question the role of secrets, which highlights the significance of bodies (human and natural sites of ritual) in ritual performance. Finally, the idea of a trace is explored. The intersecting use of a trace as the thinking-making-doing of ritual in performance articulates a connected thread that sets in motion the trace of ritual (installation, image and marked space pf ritual) as an afterlife that offers a continued space of processual ceremony for multiple effective encounters and movements..
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  • Date Issued: 2020

The validity of dismissals for refusing to accept changes to terms and conditions of employment

  • Authors: Bosch, Lauren
  • Date: 2020
  • Subjects: Employees -- Dismissal of -- Law and legislation
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: http://hdl.handle.net/10948/47336 , vital:39848
  • Description: Operational circumstances often create the need for employers to change the employment conditions of employees. Such conditions can include difficulty in obtaining raw materials which may require employees to do different work, a takeover or a merger, market shifts, orders from clients, an increase or reduction in work volumes, new technology, or even in some instances skill shortages. Regardless of the reason, in order to allow the business to remain operational, employers are often obligated to change terms and conditions of employment. Section 187 of the Labour Relations Act 66 of 1995 deals with automatically unfair dismissals and lists a number of reasons for dismissal that, if it complies with the requirements listed, the dismissal will be found to be automatically unfair. The definition was amended by the Labour Relations Amendment Act 6 of 2014 as a result of the courts incorrectly interpreting this section in Chemical Workers Industrial Union (CWIU) v Algorax (Pty) Limited (2003 11 BLLR 1081) (Algorax) and Fry's Metals (Pty) Limited v National Union of Metal Workers of South Africa and Others (JA9/01) [2002] ZALAC 25 (Fry’s Metals). Section 187(1)(c) of the LRA has always been contentious due to the fact that the definition of automatically unfair dismissals, employers’ rights to terminate contracts of employment on the basis of operational requirements and the institution of collective bargaining are intertwined. The Labour Relations Amendment Act of 2014 brought about significant changes to how section 187(1)(c) should be interpreted and fundamentally changed the enquiry that should be adopted when determining cases of this nature. The main aim of this study is to provide clarity to the question of when will it be valid and fair for an employer, in the course of restructuring his business, to dismiss any of his employees who refuse to accept the proposed changes to the terms and conditions of their employment.
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  • Date Issued: 2020

The value of economic capital as an indicator to protect prospective and existing ordinary shareholders

  • Authors: Chonzi, Tendai Day
  • Date: 2020
  • Subjects: Banks and banking -- Risk management -- South Africa , Financial services industry -- Risk management -- South Africa , ABSA Bank , FirstRand Limited , Nedbank , Standard Bank Limited , Capitec Bank (South Africa)
  • Language: English
  • Type: text , Thesis , Masters , MCom
  • Identifier: http://hdl.handle.net/10962/145807 , vital:38468
  • Description: South Africans banking sector is one of the most dominating banking sectors in Africa. The banking sector is privately owned and involves a lot of different stakeholders, who risk losing their investments. One of the stakeholders who are the bottom of the repayment chain are existing ordinary shareholders because they risk losing all their investment in the result of bankruptcy, liquidity crises or the inability of the bank to repay their shareholders. Regulators in the banking sector only protect the depositor and the stability of the banking sector but not ordinary shareholders. An internal supervisory measure called economic capital has recently received more attention because of its aim to protect ordinary shareholders and thus, existing and prospective shareholders can use its value as a protective indicator. Economic theory assumes that the higher the value of economic capital (the lower the economic capital shortfall), the lower the return on investment for existing ordinary shareholders. The aforementioned shows a trade-off between protection (economic capital) and returns. Literature by Larsson (2009) further suggests that banks are always reluctant with implementing internal measures to protect themselves because of the good regulatory regime in the sector, some banks think that they are “too big to fail” and the fact that the reserve banks are always on the standby as a bailout. The purpose of this research is to examine which of the top five commercial banks in South African actively protect their existing ordinary shareholders using the value of economic capital and possibly attract prospective ordinary shareholders, locally and internationally. The banks under study are Absa, Capitec, FirstRand, Nedbank and Standard Bank over ten years, starting from June 2009 to May 2019 and in monthly frequency. The observations totalled 120 and two models that are under the Return Series Method were in used, namely; Historical Simulation Model and Variance Covariance Model. Both models, although they were small deviations in the value of economic capital, concluded that Standard Bank protects its existing ordinary shareholders the most, followed by FirstRand, then Absa and last is Nedbank. Capitec was the only bank, after one financial shock that could not protect its existing ordinary shareholders. Moreover, evidence in the study shows a trade-off between economic capital and return on investment in the case of Capitec and Standard Bank. Standard Bank had the highest value of economic capital and second-lowest return on investment, while Capitec had the highest return on investment and lowest value of economic capital. The significant policy implication of the research is that financial institution needs to strike a balance between protection and profits; thus, a way of protecting various stakeholders. Financial shocks have proven that regulatory measures are weak and they are is need for internal measures (economic capital) which indicate how financial institution can sustain in such cases.
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  • Date Issued: 2020

The weak to strong state involvement and political accountability levels schema

  • Authors: Mbatha, Cyril N , Mkize, N N
  • Date: 2020
  • Subjects: South Africa -- Socio-economic development South Africa -- Politics
  • Language: English
  • Type: text , Text
  • Identifier: http://hdl.handle.net/10962/165364 , vital:41237
  • Description: The propositionis that socio-economic development from local to national levels often straddles at least four pathways that are driven by two main variables:the relative strength or weakness of (1) state (and government) involvementin the management of public affairs and resources and (2) the mechanisms for ensuring political accountability. The four pathways, with associated attributes, have presented opportunities or challenges that have promoted or collapsed the sustainable economic development of many post-colonial countries. Using the two main variables we can locate different countries in distinct categories (quadrants) across a two-dimensional Cartesianplane, with state involvement on the Y-axis and state and government accountability to citizens on the X-axis.
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  • Date Issued: 2020

The weight of a tooth

  • Authors: Perros, Robyn Helen
  • Date: 2020
  • Subjects: South African fiction (English) -- 21st century
  • Language: English
  • Type: text , Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/144192 , vital:38319
  • Description: My thesis is a fragmented, non-linear novella, comprised predominantly of experimental prose- poetry and fiction short-stories. I have chosen this approach in form to further explore my interest in ancestry and trauma, death and image-making, “reality” and fantasy, and the tension these invisible barriers create between the inner and outer worlds in which we simultaneously navigate, remember and forget. This thesis has been influenced both in form and content by the works of Eduardo Galeano, Osama Alomar, Lidia Yuknavitch, Susan Steinberg, Claudia Rankine, Lance Olsen, and Yasunari Kawabata, among others.
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  • Date Issued: 2020

The workload of flight attendants during short-haul flight operations: a system analysis

  • Authors: Bennett, Chloe Kayla
  • Date: 2020
  • Subjects: Flight attendants -- Health and hygiene , Employees -- South Africa -- Workload
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/123431 , vital:35437
  • Description: Background and aim: Flight attendants forms a significant part in 24-hour aviation industry. Flight attendant fatigue is a significant problem in the aviation industry as it continues to jeopardize the ability to fulfil important safety and security roles which is critical in performance duty of a flight attendant. However, little attention has been accomplished to the workload, working conditions and fatigue of flight attendants crew in transport aircraft. In addition, there is currently less research that have also embraced the problematic of smaller regional/commercial operation (short-haul flight operations) inducing fatigue among short-haul flight attendants as the nature of this operation are often characterised with high productivity expectations in a demanding environment with high time pressures resulting in high workloads and fatigue. Thus, flight attendant fatigue and workload is a worldwide challenge in this operational environment and less attention has been given to the determining factors. Therefore, the aim of the study was to determine the workload factors contributing to flight attendant fatigue during short-haul flight operations. Methods (System analysis): To achieve the research aim, the work system analysis, based on the Smith and Carayon-Sainfort model was chosen as the main research approach which was conducted in two ways; based on existing literature and secondly based on expert interviews. This method provided a systemic aspect to understand the whole work system of flight attendants work during short-haul operations in order to identify all the contributing factors to flight attendant fatigue and workload. Results: The literature analysis and the data from the expert interviews highlighted significant findings to flight attendant fatigue and workload. The reasons for flight attendant fatigue operating short-haul flights can be found at organizational, task, individual, environmental levels and tools and technologies and due to the interaction of the factors. The main factors of flight attendants’ fatigue are thought primarily as a function of scheduling due to irregular, mixed schedules with early starts and late finishes, extended duty days (long working hours), as well as high workload, due to the short turnaround flights, the number of sectors flown in a single duty period and duty length and high jobs demands. In addition, flight duty and rest regulations, confined work space in the cabin, vibrations, noise and lighting, sleeping in an unfamiliar environment, family responsibilities all add to additional stress placed on the body which can influence workload and sleep and consequently influencing fatigue. Conclusion: Overall the study determined that flight attendant fatigue is a significant problem in modern industry of short-haul operations. Using this systematic approach (work system analysis based on the framework of the work system model developed by Smith and Carayon-Sainfort (1989) allowed for an accurate representation of the complexity of flight attendant work environment in short-haul aviation industries, thus contributed to an increased understanding of fatigue and risk factors that span the entire work system and aid in identifying the patterns in combination of work system variables that are associated with increased risk to flight attendant fatigue. Overall flight attendant fatigue is a product of interactions with the short-haul environment. It can have a negative impact on safety, performance and well-being. Therefore, it needs to be managed and dealt with in the near future.
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  • Date Issued: 2020

Theoretical and photodynamic therapy characteristics of heteroatom doped detonation nanodiamonds linked to asymmetrical phthalocyanine for eradication of breast cancer cells

  • Authors: Matshitse, Refilwe , Tshiwawa, Tendamudzimu , Managa, Muthumuni , Nwaji, Njemuwa , Lobb, Kevin A , Nyokong, Tebello
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186089 , vital:44462 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117465"
  • Description: An amide mono substituted benzothiozole phthalocyanine: zinc(II) 3-(4-((3,17,23-tris(4-(benzo [d]thiazol-2-yl)phenoxy)-9-yl)oxy) phenyl)amide phthalocyanine (NH2BzPc) was covalently linked to undoped and heteroatom doped detonation nanodiamonds (DNDs): B@DNDs, P@DNDs, S@DNDs, N@DNDs, and SandN@DNDs There is a drastic decrease in highest occupied molecular orbital (HOMO) – lowest unoccupied molecular orbital (LUMO) energy gaps for nanoconjugates compared to DNDs alone. B@DNDs-NH2BzPc, SandN@DNDs-NH2BzPc, and P@DNDs-NH2BzPc showed superior photodynamic therapy (PDT) effects. DNDs-NH2BzPc also had a small HOMO-LUMO gap, but did not show improved PDT activity compared to the Pc alone, suggesting doping of DNDs is important. This study shows improved PDT effect on Michigan Cancer Foundation-7 breast cancer lines at 7.63%, 7.62% and 6.5% cell viability for P@DNDs-NH2BzPc, SandN@DNDs-NH2BzPc and B@DNDs-NH2BzPc, respectively.
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  • Date Issued: 2020

Thermal tolerance and the potential effects of climate change on coastal intertidal and estuarine organisms in the Kariega Estuary and adjacent intertitdal coastline, Eastern Cape, South Africa

  • Authors: Van der Walt, Kerry-Ann
  • Date: 2020
  • Subjects: Ectotherms -- Climatic factors , Ectotherms -- Effect of temperature on , Fishes -- Climatic factors , Fishes -- Effect of temperature on , Climatic changes -- South Africa -- Eastern Cape
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/148459 , vital:38741
  • Description: Temperature changes due to the effects of climate change are evident on all continents and oceans. As a result, there is a growing concern over how marine ectotherms will respond to extreme or fluctuating environmental temperatures. Temperature changes have strong direct and indirect effects on individual, population, and ecosystem functioning traits. A multi-scale approach determining the thermal tolerance and performance of several marine ectotherms belonging to different coastal habitats is rarely considered in thermal physiology studies but is effective for an integrated ecosystem assessment. As such, for this thesis, I aimed to quantify and compare the thermal tolerance and performance of a range of coastal marine ectotherms (fish and macro-invertebrates) with different biogeographical distributions from estuarine, subtidal and rocky intertidal habitats to available and projected in situ temperature data. This was also undertaken to gauge the local vulnerability of each species across summer and winter in a warm-temperate region of South Africa. This was done using a multi-method physiological approach, which included the dynamic method (CTmax and CTmin), static respirometry and maximum heart rate fHmax). Results of the dynamic method on several fish and macro-invertebrate species indicated that there are differences in thermal tolerance according to taxonomy, biogeography and habitat for both summer and winter. Macro-invertebrate species generally had higher CTmax endpoints, lower CTmin endpoints, higher upper and lower breadths in tolerance, higher upper and lower thermal safety margins and higher thermal scopes than the fish species. This could be a result of the macro-invertebrate species studied being less mobile compared with fish species (which are able to move to more favourable conditions) as well as having broader geographical distributions. In addition, macro-invertebrates from the intertidal rock pool habitat (Palaemon peringueyi; Pernaperna) were more tolerant of high and low temperatures compared with the macro-invertebrates from the estuarine habitat (Clibanarius virescens; Parasesarma catenatum; Upogebia africana). Overall, macro-invertebrates, with the exception of Parechinus angulosus, investigated in this study indicated that current temperatures and projected climate change scenarios across seasons would not have a significant impact on them and that they are highly adaptable to changing temperature regimes. This sign of high tolerance was further supported by the heart rates of P. perna and P. catenatum under an acute increase in temperature (1.0 °C.h-1) which showed individuals of each species physiologically depressing their metabolism until a final Arrhenius breakpoint temperature was reached (TAB). Among the fish species investigated in this study, tropical species (Chaetodon marleyi; Kuhlia mugil) had the highest CTmax and CTmin endpoints when compared with the temperate (Diplodus capensis; Sarpa salpa), warm-water endemic (Chelon dumerili; Rhabdosargus holubi) and cool-water endemic (Chelon richardsonii) fishes. This suggests that due to their lower breadths in tolerance and thermal safety margins being small, tropical species may be less tolerant of cold temperatures and thermal variability, especially in the form of summer upwelling events which are expected to increase in intensity and frequency in this region as a result of anthropogenic climate change effects. On the other hand, however, if a temperature increase of 2.0 - 4.0 °C takes place at the end of the century as predicted by the Intergovernmental Panel on Climate Change (IPCC), it is likely that tropical species such as C. marleyi will become more common. Temperate species such as D. capensis and S. salpa were able to tolerate a wide range of temperatures (wide thermal scope) compared with the other fish species. These findings may suggest that D. capensis and S. salpa are thermally resilient and may be the least vulnerable to climate change effects and temperature variability. When evaluating the different life stages of D. capensis, however, using the dynamic method (juveniles and adults), static respirometry (juveniles) and maximum heart rate (adults), results suggested that juveniles of this temperate species will be more resilient to increases in ocean temperatures compared with the adults because they have a higher thermal tolerance (CTmax/TCRIT) and a greater metabolic scope (TOPT) at higher temperatures. For both juveniles and adults, temperatures beyond 28.0 °C (upper Tpej; Tarr) will have a significant impact on their physiology. Using a multi-scale and multi-method approach thus helped to identify which species or community may be vulnerable to the effects of climate change within shallow coastal environments in this warm-temperate climate change hotspot. Adopting this type of approach will assist policy makers in developing comprehensive climate change management frameworks for coastal ecosystems globally and around South Africa.
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  • Date Issued: 2020

Thermoluminescence and phototransferred phermoluminescence of synthetic quartz

  • Authors: Dawam, Robert Rangmou
  • Date: 2020
  • Subjects: Thermoluminescence , Quartz
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/145849 , vital:38472
  • Description: The main aim of this investigation is on thermoluminescence and phototransferred thermoluminescence of synthetic quartz. Thermoluminescence was one of the tools used in characterising the electron traps parameters. The samples of quartz annealed at various temperatures up to 900̊C and the unannealed were used. The thermoluminescence glow curve was measured at 1̊C s~ 1 following beta irradiation to 40 Gy from the samples annealed at 500̊C and the unannealed consist of main peak at 70̊C and secondary peaks at 110, 180 and 310̊C. In comparison, the thermoluminescence glow curve for the sample annealed at 900̊C have main peak at 86̊C and the secondary ones at 170 and 310̊C. The kinetic analysis was carried out only on the main peak in each case. The activation energy was found to be decreasing with increase in annealing temperatures. The samples annealed at 500̊C and the unannealed were found to be affected by thermal quenching while sample annealed at 900̊C shows an inverse quenching for irradiation dose of 40 Gy. However, when the dose was reduce to 3 Gy the effects of thermal quenching was manifested. The activation energy of thermal quenching was also found to decrease with increase in annealing temperature. Thermally assisted optically stimulated luminescence measurement was carried out using continuous wave optical stimulated luminescence (CW-OSL). The samples studied were those annealed at 500̊C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The CW-OSL is stimulated using 470 nm blue LEDs at sample temperatures between 30 and 200̊C. It is measured after preheating to either 300 and 500̊C. When the integrated OSL intensity is plotted as a function of measurement temperature, the intensity goes through a peak. The increase in OSL intensity as a function of temperature is associated to thermal assistance and the decrease to thermal quenching. The kinetic parameters were evaluated by fitting the experimental data. The values of activation energies of thermal quenching are the same within experimental uncertainties for all the experimental conditions. This shows that annealing temperature, duration of annealing and irradiation dose have a negligible influence on the recombination site of luminescence using OSL. Phototransferred thermoluminescence (PTTL) induced from annealed samples using 470 nm blue light was also investigated. The quartz were annealed at 500 _C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The glow curves of conventional TL measured at 1 _C s􀀀1 following irradiation to 200 Gy shows six peaks in each case labelled I-VI for ease of reference whereas peaks observed under PTTL are referred to as A1 onwards. Only the first three peaks were reproduced under phototransfer for the sample annealed at 900̊C for 60 minutes and 1000̊C C for 10 minutes. Interestingly, for the intermediate duration of annealing of 30 minutes, the only peak that appears under phototransfer is the A1. For quartz annealed at 900̊C for 10 minutes, the PTTL appears as long as the preheating temperature does not exceed 560̊C. All other annealing temperatures, PTTL only appears for preheating to 450 and below. This shows that the occupancy of deep electron traps at temperatures beyond 450̊C or 560̊C is low. The activation energy for peaks A1, A2 and A3 were calculated. The PTTL peaks were studied for thermal quenching and peaks A1 and A3 were found to be affected. The activation energies for thermal quenching were determined as 0.62 ± 0.04 eV and 0.65 ± 0.02 eV for peaks A1 and A3 respectively. The experimental dependence of PTTL intensity on illumination time is modelled using sets of coupled linear differential equations based on systems of donors and acceptors whose number is determined by preheating temperature.
  • Full Text:
  • Date Issued: 2020

Thermoluminescence properties of potassium fluoride:

  • Authors: Ogundare, F O , Folley, Damilola E , Chithambo, Makaiko L , Arise, T O
  • Date: 2020
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/160500 , vital:40451 , https://doi.org/10.1016/j.nimb.2020.09.009
  • Description: This study is designed to examine the thermoluminescence characteristics of potassium fluoride for possible use as a thermoluminescence dosemeter. Thermoluminescence measurements were carried out at doses up to 20 Gy and heating rates between 0.2 and 4°C/s. The glow curve of the fluoride, readout at 1°Cs−1, exhibited two peaks at 130 and 250 °C. In addition, two shoulder peaks appeared at 70 and 200°C.
  • Full Text:
  • Date Issued: 2020

Think Piece. Working for Living: Popular Education as/at Work for Social-ecological Justice

  • Authors: Burt, Jane C , James, Anna , Walters, Shirley , Von Kotze, Astrid
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/388150 , vital:68310 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/165826"
  • Description: Drawing on the working lives of popular educators who are striving for socioeconomic and socio-ecological justice, we demonstrate how popular education is a form of care work which is feminised, often undervalued and unrecognised as highly skilled work. It is relational work that aims to forge solidarity with communities and the environment. Given the state of the planet, the radical transformations that are needed, and the future projection of ‘work’ as including the care economy in large measure, we argue that popular education is a generative site for further exploration of research into work and learning. However, to move popular education as work from the margins means to rethink the current economic system of value. Addressing the contradiction that undervalues work for life/living, popular education engages transformative action motivated by a deep sense of solidarity and a focus on imagining alternatives as an act of hope.
  • Full Text:
  • Date Issued: 2020

Think Piece: Learning, Living and Leading into Transgression–A reflection on decolonial praxis in a neoliberal world

  • Authors: Kulundu-Bolus, Injairu M , McGarry, Dylan K , Lotz-Sisitka, Heila
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/182406 , vital:43827 , xlink:href="10.4314/sajee.v36i1.14"
  • Description: Three scholar activists from South Africa reflect on what it means to transgress the limits of a neoliberal world and its crisis times, particularly considering transgressions in the service of a decolonial future. The authors explore three questions: i) What kind of learning can help us transgress the status quo? ii) How do we extend this learning into a commitment to actively living in transgressive ways? iii) What does it mean to lead in ways that re-generate a transgressive ethic in a neoliberal world? In a dialogical conversation format, the authors outline nine different but interconnected perspectives on learning, living and leading into transgression, with the aim of concurrently revealing the multiple layers of work that a decolonial future depends on, while demonstrating the ambitions of a pluriversal decolonial future through their writing. The intertwined narrative is not conclusive, as the processes marked out in brief are experiences that still need to be fully practised in new relations in times to come within academia-in-society-and-the-world with human and more-than-human actors. However, they do offer a generative set of questions, concepts and metaphors to give courage to boundary-dwelling scholar activists attempting transgressive research. These reflections seek to regenerate the transgressive ‘decolonial gestures’ (decolonialfutures.net) that we can undertake in a neo-liberal world, as an important part of environment and sustainability education practices. It draws out what an embodied practice of transgressive learning can entail when we become discerning of hegemonic discourses that reproduce the status quo. We pay homage to those decolonial scholars in the field of environment and sustainability education as we traverse this terrain, recognising their imagination and the transgressive movement that has come before us, but importantly we seek to also open pathways for those yet to come.
  • Full Text:
  • Date Issued: 2020

Thintitha, Celiwe

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