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Synthetic analogues of marine bisindole alkaloids as potent selective inhibitors of MRSA pyruvate kinase

  • Authors: Veale, Clinton Gareth Lancaster
  • Date: 2014 , 2014-04-02
  • Subjects: Alkaloids , Pyruvate kinase , Staphylococcus aureus , Antibiotics , Sponges -- South Africa , Imidazoles , Biological assay , Antibacterial agents
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4563 , http://hdl.handle.net/10962/d1020893
  • Description: Globally, methicillin resistant Staphylococcus aureus (MRSA) has become increasingly difficult to manage in the clinic and new antibiotics are required. The structure activity relationship (SAR) study presented in this thesis forms part of an international collaborative effort to identify potent and selective inhibitors of an MRSA pyruvate kinase (PK) enzyme target. In earlier work the known marine natural product bromodeoxytopsentin (1.6), isolated from a South African marine sponge Topsentia pachastrelloides, exhibited selective and significant inhibition of MRSA PK (IC₅₀ 60 nM). Accordingly bromodeoxytopsentin provided the initial chemical scaffold around which our SAR study was developed. Following a comprehensive introduction, providing the necessary background to the research described in subsequent Chapters, this thesis has been divided into three major parts. Part one (Chapter 2) documents the synthesis of two natural imidazole containing topsentin analogues 1.40, 1.46, five new synthetic analogues 1.58—1.61, 2.104. In the process we developed a new method for the synthesis of topsentin derivatives via selenium dioxide mediated oxidation of N-Boc protected 3-acetylindoles to yield glyoxal intermediates which were subsequently cyclized and deprotected to yield the desired products. Interestingly we were able to demonstrate a delicate relationship between the relative equivalents of selenium dioxide and water used during the oxidation step, careful manipulation of which was required to prevent the uncontrolled formation of side products. Synthetic compounds 1.40, 1.46, 1.58—1.61 were found to be potent inhibitors of MRSA PK (IC₅₀ 238, 2.1, 23, 1.4, 6.3 and 3.2 nM respectively) with 1000-10000 fold selectivity for MRSA PK over four human orthologs. In the second part of this thesis (Chapter 3) we report the successful synthesis of a cohort of previously unknown thiazole containing bisindole topsentin analogues 1.62—1.68 via a Hantzsch thiazole synthesis. Bioassay results revealed that these compounds were only moderate inhibitors of MRSA PK (IC₅₀ 5.1—20 μM) which suggested that inhibitory activity was significantly reduced upon substitution of the central imidazole ring of topsentin type analogues with a thiazole type ring. In addition in Chapter 3 we describe unsuccessful attempts to regiospecifically synthesize oxazole and imidazole topsentin analogues through a similar Hantzsch method. As a consequence of our efforts in this regard we investigated three key reactions in depth, namely the synthesis of 2.2, 3.38, 3.40, 3.41 via α-bromination of 3-acetylindole and the synthesis of indolyl-3-carbonylnitriles 2.13, 3.45—3.47 and α-oxo-1H-indole-3-thioacetamides 3.48—3.51. The investigation of the latter led to the isolation and elucidation of two anomalous N,N-dimethyl-1H-indole-3-carboxamides 3.52 and 3.53. Finally the third part of this thesis (Chapter 4) deals with in silico assessment of the binding of both the imidazole and thiazole containing bisindole alkaloids to the MRSA PK protein which initially guided our SAR studies. In this chapter we reveal that there appears to be no correlation between in silico binding predictions and in vitro MRSA PK inhibitory bioassay data. Superficially it seems that binding energy as determined by the docking program used for these studies correlated with the size of the indole substituents and did not reflect IC₅₀ MRSA PK inhibitory data. Although this led us to computationally explore possible alternative binding sites no clear alternative has been identified.
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Taxonomy and life history of the zebra seabream, Diplodus cervinus (Perciformes: Sparidae), in southern Angola

  • Authors: Winkler, Alexander Claus
  • Date: 2014
  • Subjects: Diplodus -- Classification Fish populations -- Angola Diplodus -- Angola Diplodus -- South Africa Diplodus -- Morphology Fisheries -- Angola Sparidae
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:5361 , http://hdl.handle.net/10962/d1012062
  • Description: The zebra sea bream, Diplodus cervinus (Sparidae) is an inshore fish comprised of two boreal subspecies from the Gulf of Oman and the Mediterranean / north eastern Atlantic and one austral subspecies from South Africa and southern Angola. The assumption of a single austral subspecies has, however, been questioned due to mounting molecular and morphological evidence suggesting that the cool Benguela current is a vicariant barrier that has separated many synonymous inshore fish species between South Africa and southern Angola. The aims of this thesis are to conduct a comparative morphological analysis of Diplodus cervinus in southern Angola and South Africa in order to classify the southern Angolan population and then to conduct a life history assessment to assess the life history impact of allopatry on this species between the two regions. Results of the morphological findings of the present study (ANOSIM, p < 0.05, Rmeristic = 0.42) and (Rmorphometric = 0.30) along with a concurrent molecular study (FST = 0.4 – 0.6), identified significant divergence between specimens from South Africa (n = 25) and southern Angola (n = 37) and supported stock separation and possibly sub-speciation, depending on the classification criteria utilised. While samples from the two boreal subspecies were not available for the comparative morphological or molecular analysis, comparisons of the colouration patterns between the three subspecies, suggested similarity between the southern Angola and the northern Atlantic / Mediterranean populations. In contrast, the colouration patterns between the southern Angolan and South African specimens differed substantially, further supporting the morphological and molecular results. The distinct morphological divergence between the southern Angolan and South African populations was not reflected within the life history traits of both populations. A combination of methods, including length/age frequency analyses, adult sex ratios and histological analysis was used to determine that this species is a rudimentary hermaphrodite in southern Angola. Peak spawning season was observed between June and July. The overall sex ratio (M: F) was 1:1.52 with females dominating smaller younger size classes and 50% maturity was attained at 210 mm FL and 4.6 years. Females [L(t) = 287.5(1-e⁻°·¹⁸⁽t⁻²·⁸⁴⁾)] grew significantly faster (LRT, p < 0.05) than males [L(t) = 380.19(1-e⁻°·°⁶⁽t⁻⁷·¹²⁾)]. The higher maximum age of the southern Angolan population of D. cervinus (43 years) was older than that of South African individuals sampled in the tsitsikamma national park. The similarities in the life history of the two austral populations are probably a consequence of similar selective pressures in the similar warmtemperate habitats. Evidence to support the above comments was found in the feeding study which showed that the South African and Angolan populations were almost identical, with both populations feeding primarily on amphipods and polychaete worms throughout ontogeny. In contrast, the diet of their boreal conspecifics from the Mediterranean was different, where larger individuals tended to select larger, and more robust, prey items. The life history differences observed between the boreal and austral populations can be attributed to either sampling bias or environmental factors. Sampling biases included the use of different age and growth estimation techniques, while the environmental factors would include differential selective pressures most likely driven by different resource availability and exploitation. The present study provides crucial baseline life history information of a potentially exploitable species off southern Angola as well as information on the life history plasticity of the species. Unfortunately, the current lack of uniformity in the methods used to estimate life history parameters between studies conducted on the boreal and austral populations have complicated our understanding of the evolution of various life history trends in sparid fish. From a management perspective however, the results from the present study can be used to propose management strategies for an emerging trap fishery in southern Angola. Using a balanced exploitation fishery approach (harvesting up to the size-at-100% maturity), the size of the fish traps entrance was calculated based the morphological information from this and other small sparid species that are targeted and was estimated to be 62 mm.
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Teachers' perceptions of behavioural problems manifested by Grade 11 and 12 learners in three Namibian schools

  • Authors: Akawa, Ester Anna Nelago
  • Date: 2014
  • Subjects: Education, Secondary -- Namibia School children -- Namibia -- Attitudes Learning disabilities -- Social aspects Behavior disorders in children -- Education (Secondary) -- Namibia Children with social disabilities -- Education (Secondary) -- Namibia Emotional problems of children -- Education (Secondary) -- Namibia Teachers -- Job stress -- Namibia
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1962 , http://hdl.handle.net/10962/d1010868
  • Description: In Namibia today few learners with behavioural and learning problems are within special schools as most are placed within the mainstream school system. Placing these learners within the mainstream system is part of the policy of Inclusive Education (IE) because it argues that this would benefit these learners and also save resources. IE is concerned with addressing barriers to learning and behavioural problems are regarded as one of these barriers. IE argues for a series of new approaches to the diagnosis and response to learners with behavioural problems. This poses challenges for teachers in mainstream schools. Teachers are at the forefront of this situation as they are usually the first to observe and experience the behavioural problems in the schools and are expected to respond appropriately. They find this situation both challenging and problematic. This research explores a sample of teachers’ perceptions of learners’ behavioural problems. To collect in-depth information, this study followed a qualitative approach with a case study design. The data were collected through semi-structured interviews, supplemented with observation and document analysis. The study consisted of fifteen respondents: three principals, three teacher counsellors and nine teachers from the three selected schools. This study illuminates the types of behaviour that teachers encounter, the impact of these behaviours, the factors seen as contributing to these behaviours, and how teachers and the school system deal with these behaviours. In addition the study applies Bronfenbrenner’s bioecological model (1992) to explain how the behaviours manifested by Grade 11 and 12 learners, and identified as problematic by teachers, are part of an interconnected nested social system. The results from the study indicate the manifestation of behavioural problems to be common occurrences in secondary schools are evident, amongst others, through fighting, bullying, substance abuse, truancy, and disrespect of teachers and authority. The teachers pointed to the prevalence of these problems as well as the serious impact such problems have on these learners, their fellow learners, and on the teachers. The teachers identified a complex array of what they saw as contributing factors located within the school, peer groups, family and home circumstances, the local community, as well within the national education policy, the economy and society. The study points to some specific, as well as broader, lessons and opportunities for action both for those managing the education system at the national level and for schools and teachers.
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Teachers’ experiences of change : a case study analysis of a school-based intervention in rural Kwazulu-Natal

  • Authors: James, Sally Jane
  • Date: 2014
  • Subjects: David Rattray Foundation , Educational change -- South Africa -- KwaZulu-Natal -- Case studies , Rural schools -- South Africa -- KwaZulu-Natal , Teachers -- Training of -- South Africa -- KwaZulu-Natal , Community and school -- South Africa -- KwaZulu-Natal , KwaZulu-Natal (South Africa) -- Social conditions , KwaZulu-Natal (South Africa) -- Economic conditions
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:1980 , http://hdl.handle.net/10962/d1013118
  • Description: The research presented in this thesis is a case study analysis of the school-based intervention initiated by the David Rattray Foundation [DRF]. David Rattray, a South African historian well known for his contribution to the 1879-1896 Anglo-Zulu War heritage, was murdered in January 2007. In response to his untimely death, the DRF was established by family and friends with the hope of improving education within the Umzinyathi rural municipal district of KwaZulu-Natal. This study consisted of three phases: Phase I (May-December 2011); Phase II (January-December 2012), and Phase III (December 2012-October 2013). During Phase I, the focus was on describing the broader context in which the case is located. It resulted in a narrative account of the emergence of the DRF as a non-governmental organisation [NGO] working towards change within the local rural school community. During Phase II the focus shifted from the broader socio-political and economic context to the human dimension which included teachers, principals, volunteer workers and a district official working in the schools. During Phase II the approach to change adopted by the DRF was critically analysed in relation to models of change described in the literature. Teachers’ experiences of change were also examined. Phase III was a synthesis of the findings from the first two research phases. By drawing on systems and complexity theory perspectives, insights were gained enabling a deep understanding of the DRF’s school-based intervention as a whole. This research is a qualitative study that seeks to understand individual teachers’ experiences and participation in a process of change that reaches beyond the individual and his/her immediate context. The adoption of a realist ontology (Maxwell, 2012) and application of an explanatory heuristic based on the critical realist philosophy of Bhaskar (1979, 1980, 2011) enabled the layered analysis and in-depth interpretation that characterises the study. The findings of the study reveal a complex and ongoing process of change within a rural school context. The results illuminate the efficacy of a collaborative partnership between civil society (the DRF), the local community, under the leadership of a tribal authority, and the local government (KwaZulu-Natal Provincial Department of Education). It also reveals how teachers within this particular context do not have a strong voice in the change process and hence participate only superficially in the school-based intervention. It is probable that the constraining mechanisms revealed through this research are not exclusive to this particular case study, but are common across the South African rural school context. The main contention of this thesis is that these mechanisms need further interrogation in order to enable further change and permit the active participation of teachers in the process.While the study illuminates many of the tensions and problems faced by the schools and the community in which they are located, it also highlights the achievements and selfless attitude of many people working towards change and improvement within the schools. This case study thus provides an example to all South Africans of what can be achieved with commitment and effort.
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Teachers’ understanding and implementation of inclusive education in an Eastern Cape primary school

  • Authors: Mcconnachie, Karola
  • Date: 2014
  • Subjects: Inclusive education -- South Africa , Special education -- South Africa , Education (Primary) -- Government policy -- South Africa , Alcoholism -- Social aspects -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1984 , http://hdl.handle.net/10962/d1013150
  • Description: Since 2001 the South African Department of Basic Education has been working towards implementing Inclusive Education over a twenty year period. This is in accordance with international trends in education. This study set out to investigate the implementation of Inclusive Education in a South African context by conducting a case study at an Eastern Cape no‐fee‐paying primary school. It looked at how the government policy, as set out in Education White Paper 6 (EWP6) (DoE, 2001), is understood and being implemented by teachers at the Welcome Primary school. The study further investigated the introduction of the National Strategy on Screening, Identification, Assessment and Support (SIAS strategy) (DoE, 2008a) to gain insight into how teachers identify and assess barriers to learning in an ordinary primary school. In addition it looked at emerging factors that could impact on the implementation of this policy. With 16 years teaching experience in ordinary and private schools and 19 years experience in a special needs school as a teacher, head of department and then principal, I have personal experience of the crisis in the Eastern Cape Department of Basic Education. This awareness provided the impetus and interest in researching Inclusive Education policy implementation. It is my view that only when we begin to grapple with the problems right at the source of the education crisis within the majority of the no‐fee‐paying schools that informed decisions about policy and policy implementation can be made. As I am able to understand and converse in isiXhosa, I was able to observe and experience the implementation of EWP6 and the SIAS strategy in a school that is an isiXhosa‐medium ordinary primary school and similar to the majority of ordinary public schools in the district. A qualitative research approach based within an interpretive paradigm using the case study method was used for this study. Semi‐structured interviews, detailed field notes as well as documents generated by meetings and education conferences helped me to investigate and refine my research goals. The research found that the implementation of EWP6 and the SIAS strategy posed a major challenge for the Department of Basic Education, and highlighted the significant gap between ordinary primary schools and special needs schools. However, the fact that there is a partial engagement with the process of providing inclusive education, does present some measure of hope for a better future for those learners that have experienced the injustice of exclusion from education and society. The Eastern Cape Department of Basic Education will have to ‘catch up’ to other provinces in its delivery of every child’s constitutional right to education in an inclusive school environment. Factors emerged from the study that showed that the assessment of learners’ barriers to learning with the resultant support needs was a relatively new concept, as teachers tended to rely on traditional classroom tests and simple informal classroom assessments to assess the learners. Teachers expressed a good verbal knowledge of learners with support needs but found it very challenging to put this verbal knowledge into a written document. In addition there was inadequate support from the District Based Support Team to implement the SIAS strategy. This study showed that the medical model of assessment was still being adhered to in the research district with little evidence of a move to a social model of assessment in terms of the SIAS strategy. In addition, factors emerged indicating the serious impact that alcohol abuse has on children and the society in which they live. The evidence of increasing numbers of children with Fetal Alcohol Spectrum Disorder (FASD) in a single educational district is a matter of grave concern from an educational and financial perspective. It is my contention that this is a matter of national urgency and that the Department of Basic Education must confront the escalating problem of alcohol abuse and the resultant challenges of a large number of learners with serious barriers to learning that need to be included in the education system.
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Teaching in higher education

  • Authors: Quinn, Lynn
  • Date: 2014
  • Language: English
  • Type: text , review
  • Identifier: http://hdl.handle.net/10962/66557 , vital:28963 , https://doi.org/10.1080/1360144X.2014.908094
  • Description: publisher version , As Becker and Denicolo point out in their introduction, traditionally most lecturers in higher education begin teaching with little or no formal training: ‘It is assumed if you were expert in your field you would be able, by some ill-defined means, to teach others’ (p. 1). This book aims to remedy that situation and does exactly what it sets out to do: it provides a useful, step-by-step training guide for teachers in higher education. It provides much needed advice for new academics for ways in which they can successfully combine their teaching and their research roles. It is written in an accessible style, draws on the experiences of people who have taught in higher education for some time, and provides practical advice for teaching in a range of contexts and for dealing with different challenges that may arise.
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Teaching Without Technology

  • Authors: Machanick, Philip
  • Date: 2014
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/439238 , vital:73558 , https://homes.cs.ru.ac.za/philip/Publications/_SACLA/teachWOtech-2014.pdf
  • Description: Technology is touted as a solution to problems in education. But is it? I report here on experiences with dropping use of slides in lectures and returning to working on the board. The apparent result is more interactive, engaged classes. Unfortunately there are too many other variables to make the experiences here definitive. The purpose of this paper is to provoke discussion on whether technology is overused in teaching when the goals of improving student engagement and general effectiveness of learning can be met many ways. Technology is not necessarily bad, but making it the starting point risks locking out nontechnological options.
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Teaching writing to Grade 5 English language learners in two Grahamstown East schools, South Africa : a case study

  • Authors: Julius, Lukas Homateni
  • Date: 2014
  • Subjects: English language -- Study and teaching (Primary) -- South Africa -- Grahamstown English language -- Written English English language -- Composition and exercises -- Study and teaching (Primary) English language -- Ability testing Teacher effectiveness -- South Africa -- Grahamstown Teachers -- Rating of -- South Africa -- Grahamstown Written communication Second language acquisition
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1971 , http://hdl.handle.net/10962/d1011989
  • Description: The majority of learners in South Africa are not native speakers of English, yet English is the dominant language of learning and teaching (LoLT). South African teachers, therefore, have the challenge of ensuring that their learners' literacy skills in English are adequately developed so as to facilitate learning in other curricular areas. This study investigated the way in which two Grade 5 teachers employed at different primary schools in the Eastern Cape province of South Africa taught writing to their English first additional language (EFAL) learners. English is the LoLT at both schools. A qualitative interpretive approach was used to identify factors that shape the ways these teachers handle the teaching of writing. The theoretical framework was informed by Borg's model of teacher cognition (2003) Shulman's conception of teacher knowledge (1987). Data collection methods consisted of interviews, classroom observations and document analysis. In-depth interviews, comprising two semi-structured interviews, two post-lesson informal conversational interviews and one stimulated recall interview were conducted with each teacher. Five of each teacher's writing lessons were observed and audio and video recorded. Samples of learners' written work were also collected. Analysis of the data reveals that the two teachers' beliefs, their experiences as learners themselves and subsequently as teachers, impacted on their pedagogy, as did other contextual factors (including the support they received from subject advisors, time management, and the number and range of learners in their classrooms). It was found that both teachers focused primarily on ensuring that their learners completed their written work so that it could be marked and graded in response to demands from their superiors, rather than on engaging deeply with the processes of writing (brainstorming, drafting, revising etc). Not only does this run counter to the writing pedagogy recommended in the Curriculum and Assessment Policy Statements (CAPS), but it also denies learners the scaffolding needed to help them develop the self-regulation skills needed to become independent writers. These findings demonstrate the need for assisting teachers to shift away from focusing only on learners' performance (testing and grading) towards a stronger emphasis on the process of writing. This would require that teachers develop a deeper understanding of the process/genre approaches to teaching writing advocated by CAPS.
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Temporal and spatial variability in the abundance, biomass and distribution of Palaemon peringueyi (Decapoda: Crustacea) are influenced by biological but not physico-chemical factors in the permanently open Kariega Estuary, South Africa

  • Authors: Nyalungu, Nonhlanhla P , Hodgson, Alan N , Froneman, P William , Dopolo, M , Masubelele, M
  • Date: 2014
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/68106 , vital:29200 , https://doi.org/10.2989/16085914.2014.960792
  • Description: Publisher version , Biological and physico-chemical factors affecting abundance and biomass of shrimp Palaemon peringueyi were investigated in 2010–2011 in the lower, middle and upper reaches of the freshwater-deprived permanently open Kariega Estuary. Shrimp abundance and biomass ranged from 0 to 88 ind. m−2 and 0 to 4.4 g wwt m−2, respectively. Shrimps were most abundant in the lower reach, and highest abundances and biomasses were recorded in the lower reach in June when salinities were low. The shrimps were almost always absent in the upper reach. Juveniles were found mostly in the lower and middle reaches, whereas adults were distributed in all three reaches. Regression analyses showed no statistically significant relationship for either abundance or biomass of the shrimps with temperature, salinity and dissolved oxygen (p > 0.05). The relationship between shrimp abundance and biomass and vegetation cover was positive and statistically significant (R2 = 0.109 and 0.185, respectively; p < 0.05). Vegetation cover plays an important role in determining the presence, distribution and abundance or biomass of P. peringueyi in this estuary.
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Temporal variability in the fatty acid composition of suspension-feeders and grazers on a South African rocky shore

  • Authors: Ndhlovu, Rachel Tintswalo
  • Date: 2014
  • Subjects: Lipids , Suspension feeders -- South Africa , Intertidal organisms -- South Africa , Marine invertebrates -- South Africa , Marine invertebrates -- Food -- South Africa , Marine invertebrates -- Life cycles -- South Africa , Marine invertebrates -- Reproduction , Benthos -- South Africa , Intertidal ecology -- South Africa , Fatty acids
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5949 , http://hdl.handle.net/10962/d1020879
  • Description: Numerous ecological studies have used lipids to determine trophic pathways in aquatic systems, as fatty acid profiles provide time-integrated information on an organism’s assimilated diet. Many of these studies have, however, been based on sample collections with a limited temporal scale. The trophic ecology of pelagic systems has been studied intensively using fatty acid analyses, but very little work has been directed toward benthic communities, with the intertidal being especially neglected. The investigation of trophic pathways within rocky shore communities will help us to better understand system responses to environmental changes. The determination of long term temporal variation of the food web within a community could reveal the type, magnitude, duration and frequency of highly seasonal productivity. Changes in fatty acid profiles through time in primary consumers of intertidal rocky shores are poorly understood, but represent an important step towards a more comprehensive understanding of rocky shore food webs, compared with those derived from snapshot or short-term studies. The aim of this thesis was to clarify the temporal variability in the diets of rocky shore intertidal suspension-feeders (the brown mussels Perna perna and the Cape reef worm, Gunnarea gaimardi) and grazers (the Cape sea urchin Parencinus angulosus and the Goat-eye limpet, Cymbulus oculus) on the south east coast of South Africa using fatty acid profiles, and to investigate the effects of life style (e.g. feeding mode) and life cycle on temporal variations in tissue fatty acid profiles. I had three hypotheses: firstly, that suspension-feeders experience high levels of variability in their diets through time because water quality has the potential to change quickly and drastically, whereas grazers experience less variability in their diets over time since their food sources are more constant. Secondly, the reproductive cycles of the suspension-feeder P. perna and the grazer P. angulosus affect the fatty acid composition of their gonads, with temporal variations in lipid composition reflecting changes in reproduction investment. Thirdly, the total amount of energetic reserves available for reproduction are different for each gender (females allocate more energy to egg production than males allocate to gamete production). To address these aims, fatty acid profiles of suspension-feeders and grazers were investigated over a period of twelve months (from July 2010 to June 2011) at a single site on the south east coast of South Africa. The results showed high variability in the fatty acid composition of both the suspension-feeders strongly related with changes in their food source (suspended particulate material). Furthermore, similar temporal changes in fatty acid profiles of the two suspension-feeders were observed over time, reflecting their common diet and life style. There were some inter-specific differences in the suspension-feeders, likely originating from differences in their particle capturing mechanisms. Grazers showed less variability through time compared with the suspension-feeders, with the limpets being more consistent than the sea urchins. The temporal variability in the sea urchin diets may have resulted from the highly diverse and heterogeneous food sources available to them, whereas limpets may be more selective and have a limited range of diet items. Differences between the two grazer species may have arose from differences in their feeding strategies and intertidal zonation. The fatty acid compositions of gonad tissues in both P. perna and P. angulosus showed temporal variability strongly related to reproductive cycle. Differences in the fatty acid values between females and males were apparent, with females richer in total and polyunsaturated fatty acids than males. Spawning and gametogenesis influenced the variability of fatty acids through time in both species, suggesting the importance of considering the reproductive cycle when studying lipids in rocky shore species. Little evidence of lipid transfer between muscles and gonads was seen, suggesting the importance of direct lipid storage into the reproductive tissues. The influence of diet and life history of intertidal consumers on the temporal variability of their fatty acid compositions is important to understand, as it provides us with a better understanding of the functioning of rocky shore systems. There is an enormous potential for future research in this field of study.
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Testing antivirus engines to determine their effectiveness as a security layer

  • Authors: Haffejee, Jameel , Irwin, Barry V W
  • Date: 2014
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/429673 , vital:72631 , 10.1109/ISSA.2014.6950496
  • Description: This research has been undertaken to empirically test the assumption that it is trivial to bypass an antivirus application and to gauge the effectiveness of antivirus engines when faced with a number of known evasion techniques. A known malicious binary was combined with evasion techniques and deployed against several antivirus engines to test their detection ability. The research also documents the process of setting up an environment for testing antivirus engines as well as building the evasion techniques used in the tests. This environment facilitated the empirical testing that was needed to determine if the assumption that antivirus security controls could easily be bypassed. The results of the empirical tests are also presented in this research and demonstrate that it is indeed within reason that an attacker can evade multiple antivirus engines without much effort. As such while an antivirus application is useful for protecting against known threats, it does not work as effectively against unknown threats.
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Thaumatotibia leucotreta and the Navel orange: ovipositional preferences and host susceptibility

  • Authors: Love, C N , Hill, Martin P , Moore, Sean D
  • Date: 2014
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/423811 , vital:72095 , xlink:href="https://doi.org/10.1111/jen.12126"
  • Description: False codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), presents a significant threat to the South African citrus industry. To limit income loss due to direct larval damage or from fruit rejection due to the phytosanitary status of this pest, additional pre-harvest control techniques are required for Navel oranges, which are known to be susceptible to T.leucotreta damage. A number of Navel orange cultivars have been developed, and differences in female T. leucotretaovi positional preference and susceptibility of cultivars to larval penetration are known to exist. Navel orange cultivars were grouped according to time of maturity (early, mid- and late season). Female T.leucotreta were subjected to choice and no-choice tests with these cultivars, measured by oviposition. Host susceptibility was tested by allowing neonate T. leucotreta larvae to penetrate the different Navel cultivars. In the early maturing group, Fischer Navels were least preferred for oviposition and the least susceptible to larval penetration. The mid- and late season maturing groupings showed limited differences in oviposition preference, although host susceptibility did appear to be an important factor in assessing the vulnerability of fruit to T. leucotreta. Despite being widely planted in South Africa, the mid-season Palmer Navels were highly susceptible to larval penetration, while for the late season cultivars, Cambria and Glen Ora Late were the least susceptible to T. leucotreta. As a result of these laboratory trials, it is recommended that farmers increase cultivation of Fischer Navels as the principal early season cultivar, avoid Palmer Navels in favour of other mid-season maturing cultivars and give preference to the late maturing Cambria and Glen Ora Late cultivars, to limit T. Leucotreta damage.
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The "old-new" challenges of water, sanitation and bioremediation in developing countries

  • Authors: Tandlich, Roman
  • Date: 2014
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/75982 , vital:30489 , DOI: 10.4172/2155-6199.1000e152
  • Description: Developing countries face challenges in the development of infrastructure and population growth. These lead to “side-effects" such as uncontrolled urbanization and the fact that basic services such as water and sanitation are lagging behind the actual needs on the ground. Historical challenges, lack of skilled staff and often lack of sustained funding are some of the reasons for the status quo. Extent of water and sanitation coverage often forces national and local governments to install the minimum-standard solutions, e.g. the ventilated improved pit latrines. This improves the public health status in the short-term, but causes problem in the long run due to the lack of regular maintenance such as through lack emptying of pits. Sometimes, construction of these facilities is of inferior standard. Pits are often built without lining or zero consideration is given to the local conditions in terms of soil properties, water table and the number of toilet users.
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The (in)significance of the common law? Constitutional interpretation and the Mansingh judgments

  • Authors: Krüger, Rósaan
  • Date: 2014
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/68900 , vital:29337 , https://hdl.handle.net/10520/EJC155168
  • Description: Publisher version , The law reports abound with case law on the interpretation of the provisions in the Bill of Rights. Cases on the interpretation of constitutional provisions that fall outside of the Bill of Rights are, by contrast, few and far between. (A few prominent examples are S v Mhlungu 1995 (3) SA 867 (CC); President of the Republic of South Africa v South African Rugby Football Union 2000 (1) SA 1 (CC) ('SARFU'); Matatiele Municipality v President of the Republic of South Africa 2006 (5) SA 47 (CC); Doctors for Life International v Speaker of the National Assembly 2006 (6) SA 416 (CC); Merafong Demarcation Forum v President of the Republic of South Africa 2008 (5) SA171 (CC); Chonco v President of the Republic of South Africa 2010 (6) BCLR 511 (CC); Albutt v Centre for the Study of Violence and Reconciliation 2010 (3) SA 293 (CC).) Mansingh's April 2011 application to the North Gauteng High Court was one of these unusual cases.
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The best a man can get? : an analysis of the representation of men within group situations in the advertising copy of Men’s Health and FHM from December 2006 through May 2007

  • Authors: Scott, Robert James
  • Date: 2014
  • Subjects: Men's health (Magazine) , For Him Magazine (South Africa) , Men in advertising , Sex role in advertising , Discrimination in the advertising industry , Men in mass media , Mass media criticism , Men in popular culture , Sex role in mass media , Discourse analysis -- Social aspects , Masculinity -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3535 , http://hdl.handle.net/10962/d1013576
  • Description: This study examines the production of masculinity in the advertisements of South Africa’s two most popular men’s lifestyle magazines, FHM and Men’s Health. I specifically focus on advertisements, as I argue that they play a crucial role in the re‐production of prominent discursive formations. Informed by a poststructuralist framework this study adopts Foucault’s notions of discourse, power and the constitution of the subject. Gender is conceived of within power relations, with a hierarchical relationship between masculinities and femininities. The gendered subject is also viewed as being constantly in process and being constructed performatively through material forms of practice. Focusing on group representations to establish gender hierarchies, I argue that these representations of people are performative acts, hailing the subjects who view them and producing reality through discourse. Hegemonic masculinity, which is argued to be prominent in advertising, is located at the highest point in the gender hierarchy. However, there is not one universal hegemonic masculinity, for it can vary across three discrete political contexts: the local, which is constructed in the immediate face‐to‐face interactions of families, organisations and social structures; the regional, which is constructed at the level of culture or the nation state; and the global, which is constructed in supra‐national locations. In the advertisements of FHM and Men’s Health there is interplay between the latter two as global and regional brands both advertise in these magazines. To investigate the portrayal of masculinities in these publications, this study first undertakes a content analysis to survey the “general landscape” of representation in the advertisements and then performs a critical discourse analysis to uncover “thick description” of the production of masculinity. The content analysis, finds that the advertisements in the sample validate both white and heterosexual forms of masculinity. The sample is comprised mostly of white males, white females and black males, generally proposing forms of hegemonic masculinity, emphasised femininity and complicit masculinity respectively. The representation of white males and black males is different both in terms of the frequency of representations and in the types of representations. I argued that a certain tension inhabits the resulting representations, which try to be inclusive of a multi‐racial South Africa, yet do so within a clearly hierarchical structure. An in‐depth analysis of eight texts, informed by Fairclough’s model of critical discourse analysis and Kress & van Leeuwen’s framework for visual analysis, finds similar results to the content analysis while providing insight into how various discourses produced the representations, particularly within non‐narrative advertisements.
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The characterisation of an openwork block deposit, northern buttress, Vesleskarvet, Dronning Maud Land, Antarctica.

  • Authors: Hansen, Christel Dorothee
  • Date: 2014
  • Subjects: Formations (Geology) -- Antarctica -- Queen Maud Land , Geology, Structural -- Antarctica -- Queen Maud Land , Weathering -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Physical geography -- Antarctica -- Queen Maud Land , Paleoclimatology -- Antarctica
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4878 , http://hdl.handle.net/10962/d1013138
  • Description: Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
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The characterization of DNAJC3: elucidating the function of the TPR domains

  • Authors: Mutsvunguma, Lorraine Zvichapera
  • Date: 2014
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/55874 , vital:26751
  • Description: DNAJC3 is a novel member of the DNAJ family with two domains linked to co-chaperone functions, namely the tetratricopeptide repeat (TPR) and J domain. Out of the two domains, the TPR domains are the least characterized. Therefore, the aim of this study was to characterize and elucidate additional functions of DNAJC3 TPR domains through in silico, in vitro and ex vivo approaches. Through multiple sequence and structural alignment as well as electrostatic potential analysis, DNAJC3 TPR domain were found to be most similar to TPR-containing proteins with Hsp90 or Hsp70 independent functions. In vitro pull down assays illustrated that DNAJC3 TPR domains did not interact with either cytosolic Hsp90 and Hsp70 or Grp78 and Grp94 directly, however a potential indirect interaction with Grp94 and Hsp90 was observed in mammalian lysates, via pull down assays; suggesting the formation of a complex between the proteins mediated by a specific substrate. DNAJC3 TPR domains were found to bind indiscriminately to both native and heat denatured substrates in a dose dependent manner. DNAJC3 TPR domains bound to β-galactosidase with greater affinity than malate dehydrogenase (MDH), suggesting that DNAJC3 TPR domains might exhibit substrate specificity that has not been reported before. Preliminary ex vivo analysis of DNAJC3 in mammalian cells showed that induced stress conditions did not alter the cytosolic or endoplasmic reticulum (ER) localization, or levels of DNAJC3 protein, suggesting that the protein is not stress inducible. However, protein levels of DNAJC3 were dramatically reduced by Hsp90 inhibitor novobiocin at 500 μM. Transient knockdown DNAJC3 did not change the protein levels of either Grp78 or Grp94, but decreased the protein levels of Hsp70/Hsp90 organizing protein HOP. On the other hand, protein levels of DNAJC3 were increased in HOP depleted cells. In conclusion, this study was the first to experimentally demonstrate that DNAJC3 TPR domains do not interact directly with Hsp90, Hsp70, Grp78 or Grp94, and therefore DNAJC3 is unlikely to participate in traditional co-chaperone interactions with those proteins via its TPR domain. However, the J domain is known to interact with Grp78. The discovery that DNAJC3 TPR domains resemble that of TPR-containing proteins with functions independent of Hsp90 or Hsp70 suggests that DNAJC3 might link the Hsp70/Grp78 chaperone machinery to non co-chaperone related functions, which requires further analysis.
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The comparative growth rates of indigenous street and garden trees in Grahamstown, South Africa

  • Authors: De Lacy, Peter J G , Shackleton, Charlie M
  • Date: 2014
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/180943 , vital:43672 , xlink:href="https://doi.org/10.1016/j.sajb.2014.02.007"
  • Description: Urban forestry is advocated worldwide as a means of enhancing the liveability of towns and cities, and mitigating some of the anticipated impacts of climate change. Optimisation of the benefits of trees in urban areas is dependent upon knowledge of tree form, growth, and the products and benefits that trees provide. Growth rates are a vital variable for modelling benefits, yet there is a significant gap in knowledge pertaining to growth rates of trees in urban areas, especially indigenous species in developing world countries. Here we report on growth rates of indigenous street and garden trees in Grahamstown, South Africa, using two approaches; tree ring counts on increment cores and mean rates from trees of known planting age. Growth equations for both street and garden trees were derived. There was no significant difference in mean growth rates determined via the two methods. For both methods street trees grew approximately 30% slower than trees in gardens.
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The critical implications of Ubuntu for contemporary management theory

  • Authors: Mashasha, Tamsanqa Munyaradzi
  • Date: 2014
  • Subjects: Management -- Africa -- Philosophy , Ubuntu (Philsophy) , Corporate governance -- South Africa , Management -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2879 , http://hdl.handle.net/10962/d1013116
  • Description: Since the dissolution of apartheid, corporate governance in South Africa has evolved from being a soft mainly ethical issue to a hard knowledge-based technological issue, recognised as pivotal to the success and revitalisation of the country’s capital markets and, ultimately, the prospects of the corporate economy. These high stakes have produced a succession of measures aimed at transforming corporate governance in the economy. As such, South Africa’s corporate managers are consistently faced with the seemingly unassailable obstacle of discerning and implementing technologically progressive and culturally/racially unbiased management strategies/systems. The focus of this thesis is the latter of these two obstacles. Ubuntu acts as the scope via which the issues embedded within the incumbent management strategies/systems are viewed. Ubuntu philosophy embodies a socio-cultural framework that applies to all individuals and institutions throughout the continent. It embodies collectivism and teamwork, creation of synergies and competitive advantages, humanist leadership styles and maturity, consensus in decision-making systems, effective communication, and community-based corporate social responsibility. Ubuntu is pervasive in almost all parts of Southern African continent – it is integrated into all aspects of day-to-day life throughout the region. This thesis reviews and analyses some of the lessons that can be learned through the inception of African management, more specifically Ubuntu management, within South Africa’s corporate sphere. This thesis aims to prove that there exists a need for a new South African corporate management system, one which is able to harmoniously integrate the incumbent, western-orientated management strategies and systems with one of African origins.
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The demography, spatial ecology and reproductive success of the black rhinoceros, Diceros bicornis, in Hluhluwe-iMfolozi Park, Kwazulu-Natal, South Africa

  • Authors: Nhleko, Zoliswa Nombulelo
  • Date: 2014
  • Subjects: Hluhluwe-iMfolozi Park (South Africa) , Black rhinoceros -- South Africa -- Hluhluwe , Animal populations -- South Africa -- Hluhluwe , Spatial ecology -- South Africa -- Hluhluwe , Black rhinoceros -- Reproduction
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5849 , http://hdl.handle.net/10962/d1011825 , Hluhluwe-iMfolozi Park (South Africa) , Black rhinoceros -- South Africa -- Hluhluwe , Animal populations -- South Africa -- Hluhluwe , Spatial ecology -- South Africa -- Hluhluwe , Black rhinoceros -- Reproduction
  • Description: Black rhinoceroses (Diceros bicornis) are endangered; there are only ~5000 individuals remaining worldwide. Consequently, black rhinos are managed as a metapopulation in southern Africa. This means that even though several sub-populations of black rhinos are geographically separated, they are managed as a single population. This is achieved by interchanging genetic material between the sub-populations. The main aim of the metapopulation management approach is to increase black rhino numbers in the sub-region. The Rhino Management Group (RMG), formed in 1989, was tasked with setting scientifically defensible demographic targets for the remaining black rhino sub-populations in southern Africa. In the same year, the RMG set fecundity rate at 25% and stated that each black rhino sub-population should achieve a minimum growth rate of 5% per year. The black rhino population in the Hluhluwe-iMfolozi Park (HiP), KwaZulu-Natal, South Africa, is of international importance as it has historically been a significant donor population for the translocation of black rhinos to establish new subpopulations elsewhere in the sub-region. However, the black rhino population at HiP is performing poorly in terms of reproductive success. My study was initiated to assess the reproductive life-histories of the black rhino population at HiP and to determine whether the population was meeting the demographic targets set by the RMG. I also wished to assess the use of space by black rhinos in HiP as a potential explanation for the observed reproductive output. Detailed life-history information for known black rhinos (n = 120) was used to investigate reproductive success between 1998 and 2012. The mean age at sexual maturity (ASM) was determined as 12 years, which is higher than the ASM found in black rhino populations that are considered to be performing poorly (ASM = ~ 7 years). The intercalving interval (ICI) was three years, nine months; this was also longer than the ICI of most black rhino populations. Further, the 2012 black rhino population at HiP had a growth rate of 6.4%, and the population comprised 60% adults, 23% sub-adults and 13% juveniles. Such demographics are usually observed in stable populations and it is possible that poor habitat quality could be resulting in the delayed ASM and longer ICI’s at HiP. In addition, 5% of the population is removed annually as part of the Black Rhino Range Expansion Program (BRREP) to establish new sub-populations. This could also be negatively influencing the reproductive performance of the HiP population. To determine the home range and habitat use of black rhinos at HiP, field data from 13 individual adult black rhinos (n = 9 females and 4 males) over a two-year period (2011-2012) were analyzed. Black rhino female home ranges were slightly smaller (15.4 ± 12.9 km²) than the home ranges of males (23.3 ±14.0 km²) and both sexes utilized similar habitats in the centre of the park. In addition, both the male and female black rhinos were found closer to rivers and drainage lines than expected. However, the assessment of black rhino space use in HiP was limited by a small sample size, making inferences of the impact of space use on reproductive success difficult. Nevertheless, my study suggests that food availability likely influences the location and sizes of black rhino home ranges at HiP. I believe that my study forms the first step in understanding the factors that influence the reproductive success and habitat use patterns of the current black rhino population at HiP. The information produced by my study should enable park management to identify future research to be conducted at HiP, which will yield more robust data for making informed black rhino management decisions at HiP and elsewhere.
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