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Investigating the dual influences of theory and practice on the design and implementation of a learning programme

  • Authors: Jackelman, Susan Iona
  • Date: 2012
  • Subjects: Education -- Research Education -- Philosophy Teaching -- Methodology -- South Africa -- Eastern Cape Mathematics teachers -- Training of -- South Africa -- Eastern Cape Teaching -- Aids and devices -- South Africa -- Eastern Cape Mathematics -- Study and teaching (Secondary) -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1591 , http://hdl.handle.net/10962/d1003473
  • Description: It is widely recognized that educational research and theory should be motivated by the desire to continually improve the practice of teaching. However, bridging the divide between theoretical research outcomes and the practical constraints of classroom-based teaching has proved somewhat challenging. The involvement of teachers as the 'bridge-builders' between theory and practice could provide an effective mechanism for achieving this integration. The purpose of this study is thus to investigate whether the involvement of teachers in developing and implementing a theory-based teaching module would improve teaching practice in the classroom. A teaching module was collaboratively developed by a group of teachers for Grade 9 linear functions using: the principles of mathematical proficiency postulated by Kilpatrick, Swafford and Findell, (2001); the teaching phases formulated by van Hiele (1986); and the cognitive classification of classroom activities developed by Stein and Smith (1998). This module was then taught to six Grade 9 classes by four teachers in one school in the Eastern Cape, South Africa over a period of 5 weeks. The effectiveness of the module, and its application in the classroom, was assessed in terms of: (i) the extent to which theory could be used to inform the design and development of teaching materials; (ii) the efficacy of this teaching material in promoting teaching for mathematical proficiency; and (iii) the effects of extraneous influences on the usefulness of the module in teaching for mathematical proficiency. While the theoretical framework provided a sound basis for developing the teaching module, it was found that collaboratively transforming this theory into a teaching module for practical use in the classroom is certainly possible, but it requires considerable time and effort that practising teachers do not have. Developing the depth of understanding required for mathematical proficiency also takes time - a commodity often in short supply as teachers grapple with the demands of the curriculum. Teaching for mathematical proficiency is a layered process. It starts with thinking about an idea (like a graph) that is developed out of a related concept that then has a set of characteristic algorithms and actions which are learnt and performed in sequence. Building understanding in this way ends with a student being able to visualize and conceive the graph as a structure that can be described as if it were an object (encapsulating all the previous concepts belonging to similar graphs in one idea). This development of understanding is important for mathematical proficiency but is not necessarily easy. When teaching with the module, it was necessary to create an extra opportunity for students to use procedural knowledge and repetition in order to provide enough examples to help them see the link: between linear number patterns and linear graphs. Extraneous influences on teaching for mathematical proficiency were grouped into two categories - endogenous and exogenous influences. Endogenous influences were teacher related and included the attitudes, decisions and disposition of the teacher. Exogenous influences were more contextual (and in effect out of the control of the teacher) and included teaching time available, curriculum, external assessments etc. Both of these influences were seen to affect teaching for mathematical proficiency, either promoting or inhibiting it. This research affirmed the central role that teachers play in teaching for mathematical proficiency. It is considered critical that research actively involve teachers in the evolution of mathematical theory. The development of an enabling environment (including institutional support, time, capacity, resources, skills and tools) for teachers will further enhance their capacity to teach for mathematical proficiency.
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Investigating the impact of brand reputation on brand architecture strategies : a study on a South African automotive company

  • Authors: Waddington, Andrew John
  • Date: 2012
  • Subjects: Branding (Marketing) -- Case studies Automobile industry and trade -- South Africa -- Case studies Toyota Jidōsha Kōgyō Kabushiki Kaisha -- Case studies Automobiles -- Marketing -- Case studies Product management -- Case studies Branding (Marketing) -- Management -- Case studies Corporate image -- Management -- Case studies Brand name products -- South Africa -- Case studies
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:1179 , http://hdl.handle.net/10962/d1002796
  • Description: The brand architecture of an organisation has become increasingly important to global management and marketing professionals, as it deals with structures and designs of brands which are constantly influenced by a changing environment. The market realities and changes brands face continuously impact the reputation of the brand, which is critical to sustain competitive advantage. The primary purpose of the study was to investigate the impact brand reputation has on brand architecture strategies, and an automotive company was chosen as the focus of the research. This research aims to help managers, marketers and brand owners make informative decisions regarding the brand architecture of a company. A quantitative content analysis methodology was used along with a webpage keyword counting application (WebWords). The application was used based on the principles outlined by Corporate Brand and Reputation Analysis (COBRA), which uses a four step progressive filtering process in filtering traditional and consumer generated media. The results from WebWords were then aligned to the brand architecture strategies from the brand relationship spectrum (BRS) to gain insight as to which of the strategies from the BRS were most vulnerable to reputational damage. The study found that the branded house and sub-brand strategies were most vulnerable to reputational damage based on the number reputational hits received. The connection between the master brand and the sub-brands could cause both brands to be affected should any reputational issues arise.
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Investigating the incorporation of education about, in/through and for the environment in the Geography junior phase curriculum: a case study of three Namibian schools

  • Authors: Anyolo, Eveline Omagano
  • Date: 2012
  • Subjects: Environmental education -- Namibia -- Case studies Education, Primary -- Curricula -- Namibia Geography teachers -- Namibia -- Case studies
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1594 , http://hdl.handle.net/10962/d1003476
  • Description: This study was carried out to investigate how education about, in/through and for the environment is incorporated in the Namibian Geography Junior Phase curriculum in three schools in Oshana Education Region. Education about, in/through and for the environment are three forms of environmental education identified by Fien (1998). This study is a qualitative, interpretive case study. It reviews the activities, content knowledge, methods, competencies and resources and describes how they were used by teachers in fostering education about, in/through and for the environment in the curriculum. Data was generated through document analysis, observations and semi-structured interviews. The results were interpreted and discussed in relation to the research question which is: How is education about, in/through and for the environment incorporated in the Geography Junior Phase curriculum? Key findings of the study suggested that teachers incorporated education about, in/through and for the environment in their teaching. Teachers used the prescribed syllabus to structure their environmental learning lessons. Most methods, resources and activities used by the teachers promoted education about the environment. The study also found that most types of knowledge about the environment were covered by the teachers. This enabled learners to examine the complexity and interrelatedness of natural systems. The study found that the way the resources were used exclusively supported education about the environment. Linking learning to local context in this study encouraged education in/through the environment and enhanced the learning process through real life experience. The study also found that, although teachers taught their learners for the environment, they did not empower them in taking actions towards environmental problems. Based on the insights offered by this research, the study identified further support required by teachers and made recommendations for effective incorporation of about, in/through andfor the environment in the curriculum.
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Investigating the nature of epistemological access afforded by a first-year chemistry intervention programme : towards a pedagogy of possibility!

  • Authors: Southwood, Sue , Samson, Duncan , Sewry, Joyce D
  • Date: 2012
  • Language: English
  • Type: Article
  • Identifier: vital:6083 , http://hdl.handle.net/10962/d1003918 , http://hdl.handle.net/10520/EJC132134
  • Description: This paper describes a study motivated by a general concern to capture innovative and effective practice in higher education, supporting a move towards a ‘pedagogy of possibility’, ‘understanding who we are and what we do’, opening up ‘new ways of being in the university’ (Boughey, 2010). The research seeks to investigate the nature of epistemological access afforded by a first-year chemistry intervention programme, with an ultimate aim of contributing to the development of effective spaces for learning in higher education. The study is regarded as dynamic in terms of its emergence from, and its intended contribution to, practice. The outcome of this somewhat emergent process not only suggests relevant and useful insights into educational practice in higher education but also offers an appropriate and meaningful model for conducting research in higher education. This research contributes to the field both pedagogically as well as methodologically.
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Investigating tools and techniques for improving software performance on multiprocessor computer systems

  • Authors: Tristram, Waide Barrington
  • Date: 2012
  • Subjects: Multiprocessors , Multiprogramming (Electronic computers) , Parallel programming (Computer science) , Linux , Abstract data types (Computer science) , Threads (Computer programs) , Computer programming
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4655 , http://hdl.handle.net/10962/d1006651 , Multiprocessors , Multiprogramming (Electronic computers) , Parallel programming (Computer science) , Linux , Abstract data types (Computer science) , Threads (Computer programs) , Computer programming
  • Description: The availability of modern commodity multicore processors and multiprocessor computer systems has resulted in the widespread adoption of parallel computers in a variety of environments, ranging from the home to workstation and server environments in particular. Unfortunately, parallel programming is harder and requires more expertise than the traditional sequential programming model. The variety of tools and parallel programming models available to the programmer further complicates the issue. The primary goal of this research was to identify and describe a selection of parallel programming tools and techniques to aid novice parallel programmers in the process of developing efficient parallel C/C++ programs for the Linux platform. This was achieved by highlighting and describing the key concepts and hardware factors that affect parallel programming, providing a brief survey of commonly available software development tools and parallel programming models and libraries, and presenting structured approaches to software performance tuning and parallel programming. Finally, the performance of several parallel programming models and libraries was investigated, along with the programming effort required to implement solutions using the respective models. A quantitative research methodology was applied to the investigation of the performance and programming effort associated with the selected parallel programming models and libraries, which included automatic parallelisation by the compiler, Boost Threads, Cilk Plus, OpenMP, POSIX threads (Pthreads), and Threading Building Blocks (TBB). Additionally, the performance of the GNU C/C++ and Intel C/C++ compilers was examined. The results revealed that the choice of parallel programming model or library is dependent on the type of problem being solved and that there is no overall best choice for all classes of problem. However, the results also indicate that parallel programming models with higher levels of abstraction require less programming effort and provide similar performance compared to explicit threading models. The principle conclusion was that the problem analysis and parallel design are an important factor in the selection of the parallel programming model and tools, but that models with higher levels of abstractions, such as OpenMP and Threading Building Blocks, are favoured.
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Investigating water knowledge flow to communities

  • Authors: Burt, Jane C , Berold, Robert
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/433013 , vital:72923 , xlink:href="https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20288-11.pdf"
  • Description: Those of us who work in water resource management have found that very few knowledge/research resources are accessible to most people. This happens because resources are not disseminated properly (or at all), or because they are inappropriately technicist, or because potential readers are hampered by low education. What is the best way to make water research accessible to as many people as possible and especially to people whose lives would be affected by the research? In the early 1980s an attempt was made to address this issue when Robert Berold edited People's Workbook (EDA 1981), a user-friendly book that presented basic technical information for rural people – not only on water, but also on agriculture, health, building construction, and income generation. The book included real-life interviews, and was disseminated by rural fieldworkers. Perhaps because there was nothing like it at the time, it was enormously popular.
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Investigation of the effect of short duration breaks in delaying the onset of performance related fatigue during long distance monotonous driving at different times of the day

  • Authors: Ndaki, Ntombikayise
  • Date: 2012
  • Subjects: Fatigue -- Physiological aspects , Drowsiness -- Physiological aspects , Automobile driving -- Physiological aspects , Traffic safety -- South Africa , Automobile driving -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5170 , http://hdl.handle.net/10962/d1016353
  • Description: Road traffic accidents are a serious burden to the health systems of many countries especially in South Africa. Research aimed at reducing traffic related accidents is of importance as traffic crashes are rated as the second leading cause of fatalities in South Africa and ninth in the world. Despite the extensive efforts into research and development of new technology, driver fatigue still remains a cause of vehicle accidents worldwide. Fatigue plays a role in up to 20% of vehicle accidents with many being serious or fatal. Numerous coping behaviours are employed by drivers to counteract the negative effects of fatigue. The most common coping behaviours include taking short naps, talking to passengers, listening to the radio, opening windows and drinking stimulants. Driving breaks have long been identified as an effective countermeasure against fatigue. Most research done in driving breaks has investigated the duration of the breaks, activity undertaken during the break and the frequency of the breaks taken outside the vehicle. However limited literature is available on the effectiveness of breaks in counteracting the effects of fatigue. The objective of the current study was aimed at assessing whether short duration breaks are an effective countermeasure against fatigue. Physiological, neurophysiological, subjective and performance measures were used as indicators for fatigue. Additional focus of the research was determining whether breaks were more or less effective at counteracting the effects of fatigue at different times of day. Twelve participants were recruited for the study, six males and six females. The participants were required to perform a driving task on a simulator for 90 minutes. The study consisted of four independent conditions, namely driving during the day with breaks, driving during the day without breaks, driving during the night with breaks and driving during the night without breaks. The without breaks conditions were similar except that they occurred at different times of the day, one session at night and the other session during day time, as was the case for the conditions with breaks. The driving task used in the current study was a low fidelity simulator tracking task. The participants were required to follow a centre line displayed on a tracking path as accurately as possible. The measurements that were recorded in this study included physiological, performance, subjective and neurophysiological. Physiological measures included heart rate and heart rate variability (frequency domain) and core body temperature. The ascending threshold of the critical flicker fusion frequency was the only neurophysiological measurement included in the current investigation. Performance was quantified by mean deviation from a centre line participants were meant to track. Two rating scales were used: Karolinska sleepiness scale and the Wits sleepiness scale were used for the measurement of subjective sleepiness. Heart rate, heart rate variability and mean deviation were measured continuously throughout the 90 minute driving task. Critical flicker fusion frequency, temperature and the subjective scales were measured before and after the 90 minute driving task. The results indicated that the short duration breaks during day time had a positive effect on driving performance; however the breaks at night had a negative effect on driving performance. Heart rate was higher during the day compared to night time and the heart rate variability high frequency spectrum values were lower during the day condition, to show the activation of the sympathetic nervous system which is characteristic of day time. The night conditions had lower heart rate values and higher heart rate variability high frequency values, which show the activation of the parasympathetic nervous system which is dominant during periods of fatigue and night time. Subjective sleepiness levels were also higher at night compared to day time.
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Is there no urban forestry in the developing world?

  • Authors: Shackleton, Charlie M
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/181060 , vital:43695 , xlink:href="https://doi.org/10.5897/SRE11.1117"
  • Description: Urban forestry and greening offer a multitude of benefits to the inhabitants of towns and cities. However, the nature and magnitude of these frequently depend upon the context. Yet, at first glance, the developing world context around urban forestry debates seems to be poorly represented in the international peer-reviewed literature. This is examined in this paper, followed by a brief outline of ten key research areas for urban forestry in the developing world. A survey of the peer-reviewed literature confirms that almost 80% of articles come from the developed world context. This correlates with the greater availability of research finance and personnel from developed regions. However, there are urban forestry questions and issues that require examination in the developing world because they cannot simply be transferred from knowledge gleaned from and tested in a developed world context. Ten of these are briefly outlined as a catalyst towards greater attention to urban forestry in the developing world and their contributions to global debates and models.
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Isolation, structural characterisation and evaluation of cytotoxic activity of natural products from selected South African marine red algae

  • Authors: Knott, Michael George
  • Date: 2012
  • Subjects: Marine algae -- South Africa , Red algae -- South Africa , Pharmaceutical chemistry
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3862 , http://hdl.handle.net/10962/d1015460
  • Description: The medicinal chemistry of selected marine algae indigenous to South Africa was investigated. Following the isolation and characterisation of a number of new and known compounds, the associated in vitro cytotoxic profiles of these new compounds was investigated. Plocamium maxillosum yielded two new cyclic polyhalogenated monoterpenes which were characterised as 2E-chloromethine-4E-chlorovinyl-4-methyl-5-cyclohexen-1-one (2.1) and 2Z-chloromethine-4E-chlorovinyl-4-methyl-5-cyclohexen-1-one (2.2) on the basis of one and two dimensional NMR spectroscopic data and MS analysis. These compounds were also found to have good cytotoxic activity against breast cancer cell lines. Although these compounds are based on a regular monoterpene skeleton, they represent an uncommon feature not often seen in cyclic halogenated monoterpenes from marine algae. Plocamium robertiae yielded one new cyclic polyhalogenated monoterpene identified as 4,5- dibromo-5-chloromethyl-1-chlorovinyl-2-chloro-methylcyclohexane (2.6) and one known compound called 2,4-dichloro-1-chlorovinyl-1-methylcyclohexane-5-ene or Plocamene D (2.9). Portieria hornemannii was collected from Port Edward in Natal and yielded three new compounds, namely; 3Z-1,6-dibromo-3-(bromomethylidene)-2,7-dichloro-7-methyloctane (3.1), 1E,3Z-1,6-dibromo-3-(bromomethylidene)-7-chloro-7-methyloct-1-ene (3.2), 1Z,3Z- 1,6-dibromo-3-(bromomethylidene)-7-chloro-7-methyloct-1-ene (3.3), and one known compound, namely; 3S,6R-6-bromo-3-(bromomethyl)-3,7-dichloro-7-methyloct-1-ene (3.4). Compounds 3.1 and 3.2 showed no cytotoxic activity against breast cancer cells. Another Portieria hornemannii sample was collected from Noordhoek in the Eastern Cape, it yielded one known compound referred to as 3Z-6-bromo-3-(bromomethylidene)-2,7- dichloro-7-methyloct-1-ene (3.5), as well as one new compound called portieric acid A (3.6) or 5-bromo-2-(bromomethylidene)-6-chloro-6-methylheptanoic acid. Portieric acid A showed slight cytotoxic activity and also represents a new class of compound within the genus Portieria. The isolation of secondary metabolites from the South African red alga, Laurencia glomerata, yielded two known compounds; 7-hydroxylaurene (4.9) and cis-neolaurencenyne (4.12), as well as one chamigrane related compound (4.11). Laurencia flexuosa yielded one known compound called 3Z-bromofucin (4.13). Using 1H NMR, GC and molecular systematics, a novel method for identifying different species of Laurencia was also investigated.
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Issues and challenges facing school libraries: a case study of selected primary schools in Gauteng Province, South Africa

  • Authors: Paton-Ash, Margaret Sanderson
  • Date: 2012
  • Subjects: School libraries -- South Africa -- Gauteng Libraries and state -- South Africa -- Gauteng Libraries and schools -- South Africa -- Gauteng Library planning -- South Africa -- Gauteng Libraries and education -- South Africa -- Gauteng
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1660 , http://hdl.handle.net/10962/d1003543
  • Description: Fewer than 8% of schools in South Africa have functioning libraries. There is no national policy for school libraries which compels School Governing Bodies and principals to have a library in their schools. This qualitative study, based on grounded theory, investigated ten primary schools in Gauteng that had libraries, or were in the process of setting up a library with the intention of providing a rich description of the issues and challenges facing these schools. The schools were chosen on the basis of location (Soweto and Johannesburg), and the school fees that were paid in a continuum from low/no fee paying schools to the fee paying ex Model-C schools. The resourcing of the school library, the operation of the school library and the role of the library were examined. The findings highlight the lack of a national policy, of school library posts, the theft of computers as a result of the lack of security, as well as the lack of understanding by teachers of the role the library in teaching and learning. Furthermore, there appears to be a disjuncture between the trends evident in the international literature on school libraries and what is actually happening in the primary school libraries in my study. Most significantly low/no fee paying schools with libraries were the exception and those that did have libraries were as a result of the enthusiasm and efforts of one or two individuals with the backing of the principal. Ex-Model C schools had the advantage in terms of the provision and staffing of school libraries as they had the funds to support them and, in some cases, a school librarian, provided that the principal supported the idea of a school library. In all the schools, the belief in the importance of the library regarding reading and literacy was the main motivating factor in establishing or maintaining the school library. A growing public awareness of the value of school libraries was an encouraging trend that emerged from my study.
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Judicial intervention in Kenya's constitutional review process

  • Authors: Juma, Laurence , Okpaluba, Chuks
  • Date: 2012
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/128412 , vital:36107 , https://heinonline.org/HOL/Page?handle=hein.journals/wasglo11amp;div=13amp;g_sent=1amp;casa_token=amp;collection=journals
  • Description: The constitutional reform process in Kenya, which culminated in the promulgation of a new constitution in August 2010, has been a subject of much study and scholarly deliberation.' That it ended on a rather positive note as compared to those in Zambia, Malawi, and even Zimbabwe, is seen by many as proof that Africans could, after all, redesign their constitutional frameworks to weed out moribund structures and entrench systems of democratic governance. But the Kenyan experience also indicates a rather unfortunate trend where constitutions are never allowed to grow or mature with statehood.
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Juta and Co Ltd and the South African Law Journal: a milestone

  • Authors: Glover, Graham B
  • Date: 2012
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/70539 , vital:29673 , https://hdl.handle.net/10520/EJC54018
  • Description: It might be said that the relationship between a journal and its publisher is something like an arranged marriage: it is cultural rather than romantic, and it is more of a business deal carefully considered by those in charge of both sets of parties with quiet aspirations of a solid future than about the passion and emotion of the wedding. There is much that is controversial about the social construct of an arranged marriage, but the relationship between the South African Law Journal (SALJ) and Juta and Company Ltd (to be referred to hereafter by its more common sobriquet in the legal profession: 'Juta') does seem to give credence to one of the most popular psychologies about the institution: that very often the relationship, a little uncertain at the start, grows stronger and more secure over time. The year 2011 marked the centenary of the publication of the SALJ by Juta: an exceptional anniversary. This is not a time to review the history of the relationship between Juta, the SALJ, and its various editors. This task has been carried out several times by Ellison Kahn in his inimitable style (see 'Fifty years of the Journal under Union' (1960) 77 SALJ 162; 'The birth and life of the South African Law Journal' (1983) 100 SALJ 594; 'Foreword' to Patricia Cobbledick and Mervyn Dendy The South African Law Journal Cumulative Index 1973-1997 (1997); 'Farewell! Fifty years' hard work comes to an end' (1999) 116 SALJ 691; 'Speech at the Juta Dinner at the South African Law Journal Jubilee Conference' (2004) 121 SALJ 271). But a short commemorative tribute seems apt to commemorate the liaison between the two parties.
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Language and social services in rural North West the status of Setswana

Large pollen loads of a South African asclepiad do not interfere with the foraging behaviour or efficiency of pollinating honey bees

  • Authors: Coombs, Gareth , Dold, Anthony P , Brassine, Eleanor I , Peter, Craig I
  • Date: 2012
  • Language: English
  • Type: Article
  • Identifier: vital:6509 , http://hdl.handle.net/10962/d1005936
  • Description: The pollen of asclepiads (Asclepiadoideae, Apocynaceae) and most orchids (Orchidaceae) are packaged as large aggregations known as pollinaria that are removed as entire units by pollinators. In some instances, individual pollinators may accumulate large loads of these pollinaria. We found that the primary pollinator of Cynanchum ellipticum (Apocynaceae-Asclepiadoideae), the honey bee Apis mellifera, accumulate very large agglomerations of pollinaria on their mouthparts when foraging on this species. We tested whether large pollinarium loads negatively affected the foraging behaviour and foraging efficiency of honey bees by slowing foraging speeds or causing honey bees to visit fewer flowers, and found no evidence to suggest that large pollinarium loads altered foraging behaviour. C. ellipticum displayed consistently high levels of pollination success and pollen transfer efficiency (PTE). This may be a consequence of efficiently loading large numbers of pollinaria onto pollinators even when primary points of attachment on pollinators are already occupied and doing so in a manner that does not impact the foraging behaviour of pollinating insects.
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Layer by Layer Electrode Surface Functionalisation Using Carbon Nanotubes, Electrochemical Grafting of Azide‐Alkyne Functions and Click Chemistry

  • Authors: Coates, Megan , Griveau, Sophie , Bedioui, Fethi , Nyokong, Tebello
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/243509 , vital:51159 , xlink:href="https://doi.org/10.1002/elan.201200240"
  • Description: Ferrocene was covalently bonded to a layer of adsorbed single-walled carbon nanotubes on a glassy carbon electrode surface using electrochemical grafting and click chemistry. Grafting of the 4-azidobenzenediazonium salt onto the surface was accomplished by electrochemical reduction. The surface-bound azide groups, with the use of a copper(I) catalyst, were reacted with ethynylferrocene to form covalent 1,2,3-triazole bonds by click chemistry. This layer by layer construction of the electrode surface results in stable electrodes by combining good electrical conductivity and increased surface area of the nanotubes with the versatility of the Sharpless click reaction.
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Leopard population density, home range size and movement patterns in a mixed landuse area of the Mangwe District of Zimbabwe

  • Authors: Grant, Tanith-Leigh
  • Date: 2012
  • Subjects: Leopard -- Monitoring -- Zimbabwe , Leopard -- Conservation -- Zimbabwe , Wildlife monitoring -- Zimbabwe , Wildlife conservation -- Zimbabwe
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5726 , http://hdl.handle.net/10962/d1005412 , Leopard -- Monitoring -- Zimbabwe , Leopard -- Conservation -- Zimbabwe , Wildlife monitoring -- Zimbabwe , Wildlife conservation -- Zimbabwe
  • Description: Trophy hunting is often employed as a conservation management tool for large predators. However, in order for this method to succeed, hunting levels must be sustainable. Very little robust population data exist for African leopards (Panthera pardus) in general, and almost no density or spatial ecology data exist for leopards in Zimbabwe. Zimbabwe has one of the highest annual CITES leopard trophy hunting quotas in Africa, the sustainability of which has not been assessed, despite large scale landuse changes over the last 12 years. The focal area of this study was within the Mangwe district, in the south-west of Zimbabwe. The region is dominated by cattle and wildlife ranches, with high levels of leopard hunting, making it an important area for assessing leopard population density and spatial ecology. Three population density estimation methods were employed in my study: a spoor index survey, an unbaited camera-trapping survey and a baited camera-trapping survey. Using three calibration equations, spoor indices appeared to underestimate the leopard population (1.28-3.29 leopards/ 100 km²) as the equations were calibrated for areas with different habitats and leopard densities. In addition, the unbaited camera survey only produced six leopard photographs, unsuitable for individual identification and analysis. By contrast, the baited camera survey produced 292 identifiable leopard photographs, from which 13 individuals were identified. Density estimates calculated using the programme CAPTURE and the M[subscript]h model with the Mean Maximum Distance Moved Outside of Study Area (MMDMOSA) buffer method (4.79±0.83 leopards/100 km²), and the programme SPACECAP, using a buffer of 2.5 km (5.12±0.62 leopards/100 km²), appeared to generate the most reliable leopard population estimates. To assess the spatial ecology, three leopards (one male, two females) were captured and fitted with GPS collars. The home range estimates of the three leopards (95% Kernel UD: male 263 km², females 31 and 45 km²) were smaller than those of leopards in more arid regions, but larger than those of mesic habitats. This suggests that the Mangwe area has a higher quality habitat than the arid regions of Namibia, but less suitable habitat than protected bushveld areas (e.g. Kruger National Park, South Africa). My data represents the first robust leopard density and home range assessment for Zimbabwe. In addition, my results indicate that the current hunting quota issued to the Mangwe area is unsustainable. Consequently, I recommend revising the quota to five leopards for the entire area, and halving the current national leopard quota to 250, until a national leopard census is completed.
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Life history strategy and population characteristics of an unexploited riverine cyprinid, Labeo capensis, in the largest impoundment in the Orange River Basin

  • Authors: Winker, A Henning , Weyl, Olaf L F , Booth, Anthony J , Ellender, Bruce R
  • Date: 2012
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/124910 , vital:35709 , https://doi.10.3377/004.047.0124
  • Description: Common carp (Cyprinus carpio) is one of the world’s most widely introduced and established freshwater fishes (Casal 2006). The species is considered to be one of the eight most invasive freshwater fishes (Lowe et al. 2000) and worldwide, it accounts for most of the records of successful establishments and adverse ecological effects (Casal 2006; Kulhanek et al. 2011). This invasive success suggests that feral C. carpio is equipped with a set of adaptable life history attributes that allow it to successfully colonise a wide range of habitats (Koehn 2004; Zambrano et al. 2006; Britton et al. 2007). Where feral C. carpio occurs in high densities, it is often perceived as an invasive pest species (Sivakumaran et al. 2003; Brown and Walker 2004; Koehn 2004) because it can have severe impacts on habitat heterogeneity and biodiversity by increasing water turbidity through its bottom feeding behaviour, increasing nutrient availability, decreasing benthic and macrophyte density and diversity, altering zooplankton assemblages and decreasing endemic fish abundance (Zambrano et al. 2001; Khan 2003; Kulhanek et al. 2011). Within south-east Australia, for example, C. carpio comprises the largest proportion of the ichthyobiomass in the continent’s largest river system – the Murray–Darling Basin (Gehrke et al. 1995). As a consequence, serious concerns about its threat to endemic freshwater species (Koehn 2004) have prompted several of the most recent investigations into its life history (e.g. Sivakumaran et al. 2003; Smith and Walker 2004; Brown et al. 2005). Other potential threats posed also include competition with indigenous species and the spread of diseases and parasites (Dudgeon et al. 2006). In South Africa, for example, Asian tapeworm Bothriocephalus acheilognathi is now widely distributed in seven river systems and has infected eight novel cyprinid hosts due to the translocation of infected by C. carpio from a centralized aquaculture facility (Stadtlander et al. 2011).
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Life-history and stock assessment of Clarias Gariepinus in the Okavango Delta, Botswana

  • Authors: Bokhutlo, Thethela
  • Date: 2012
  • Subjects: Catfishes -- Botswana -- Okavango River Delta , Clarias gariepinus , Aquaculture -- Botswana -- Okavango River Delta
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5297 , http://hdl.handle.net/10962/d1005142 , Catfishes -- Botswana -- Okavango River Delta , Clarias gariepinus , Aquaculture -- Botswana -- Okavango River Delta
  • Description: Large catfishes (Clarias gariepinus & Clarias ngamensis) are not exploited commercially in the Okavango Delta, Botswana. They however constitute a large proportion of the gill net fishery catch (23 %) albeit as by-catch, coming second after cichlids (70 %). Monthly experimetal gill net sampling over 8 years showed that C. gariepinus was the most abundant species in the Okavango Delta by mass making up 37 % of the catch composition by fresh weight. Despite the relatively high abundance of C. gariepinus in the Okavango Delta, its status has never been fully assessed. For this reason, this study aimed to assess the status of C. gariepinus in the Okavango Delta with the particular goal to determine if the species could support a directed commercial gill net fishery. Investigation of the effects of the flood pulse on abundance of C. gariepinus showed that variability in water levels was the major driver of population abundance for this species. Three biological variables: (1) catch per unit effort (CPUE); (2) % catch composition and (3) Shannon's diversity index (H') exhibited a negative and significant relationship with the flood index within a year. The variation in these variables was statistically significant between months. There was a weak positive relationship between water levels and the biological variables between years suggesting increase in productivity of the system at high water levels without a lag period. Age and growth were determined using sectioned otoliths. Edge analysis showed that growth zone deposition occurred during the drawdown period in summer when water temperature and day length were increasing. The maximum recorded age was 15 years. Growth of this species was best described by the linear models (y = 21.50x + 427.39 mm LT; r² = 0.35) for females and (y = 23.79x + 440.83 mm LT; r² = 0.38) for males. The von Bertalanffy growth model described growth as Lt = 10000(1- exp(-0.002(t + 18.07))) mm LT for combined sexes Lt = 10000(1- exp( -0.002(t + 18.50))) mm LT , for females and Lt =908(1-exp(-0.076(t+7.95)))mmLT for males. Age at 50 % maturity was attained in the first year of life. Spawning occurred throughout the year with an apparent peak between November and April. The mean total annual mortality rate (Z) was 0.25 per year. The mean annual natural mortality rate (M) was 0.20 per year and fishing mortality (F) was calculated at 0.05 per year. The life history strategy of C. gariepinus was in between the periodic and opportunistic strategies. Therefore management of this species should be aimed at maintaining a healthy adult population and age structure. Since a large portion of the Okavango Delta is already protected and most other parts are also inaccessible to fishers there are enough spatial refugia for the species and the status quo should be maintained. Under this scenario, there is no need for regulation of the current mesh sizes because the species is harvested after maturity and replenishment of exploited populations will always occur from other parts of the system. Per recruit analyses indicate that the current fishing mortality maintains spawner biomass at levels greater than 90 % of pristine levels. Therefore a commercial fishery may be established using mesh 93 mm to maximize yield with a rotational harvesting strategy. Close monitoring is essential to ensure that re-colonization of overexploited habitats does indeed occur. Recreational angling and commercial gill net fishing need to be separated on a spatial and temporal scale during the feeding run to minimize potential conflicts.
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Life-history characteristics of an age-validated established invasive African sharptooth catfish, Clarias gariepinus, population in a warm–temperate African impoundment

  • Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
  • Date: 2012
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/124921 , vital:35710 , https://doi.10.3377/004.048.0225
  • Description: African sharptooth catfish Clarias gariepinus (Burchell, 1822) is a widely distributed fish that has now invaded water bodies in South America, Eastern Europe, Asia and South Africa (Cambray 2003). In South Africa it is native as far south as the Orange-Vaal river system, but inter-basin water transfer schemes (IBWTs), illegal stocking by anglers and from aquaculture has resulted in the establishment of extralimital populations in almost all river systems (van Rensburg et al. 2011). Within the Eastern Cape Province, C. gariepinus has invaded the Great Fish and Sundays rivers through IBWTs, that connect the Orange River to the Great Fish River and then to the Sundays River system which flows directly into Darlington Dam (Kadye & Booth 2013a) (Fig. 1). Soon after the completion of the IBWTs sharptooth catfish were recorded in Grassridge Dam in 1976 (Laurenson & Hocutt 1985), and later from Darlington Dam in 1981 (Scott et al. 2006). Although Cambray & Jubb (1977) are of the opinion that the species was translocated prior to the IBWT connection, there is now a permanent corridor between the Orange River and its receiving river systems that can facilitate the continued introduction of non-native Orange River fishes and other aquatic biota.
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Like a bolt from the blue : phthalocyanines in biomedical optics

  • Authors: Sekkat, N , Van den Berg, H , Nyokong, Tebello , Lange, N
  • Date: 2012
  • Subjects: Biomedical optics Fluorescence diagnosis Phthalocyanines NIR dyes Photodynamic therapy
  • Language: English
  • Type: Article
  • Identifier: vital:6597 , http://hdl.handle.net/10962/d1004346 , http://dx.doi.org/10.3390/molecules17010098
  • Description: The purpose of this review is to compile preclinical and clinical results on phthalocyanines (Pcs) as photosensitizers (PS) for Photodynamic Therapy (PDT) and contrast agents for fluorescence imaging. Indeed, Pcs are excellent candidates in these fields due to their strong absorbance in the NIR region and high chemical and photo-stability. In particular, this is mostly relevant for their in vivo activation in deeper tissular regions. However, most Pcs present two major limitations, i.e., a strong tendency to aggregate and a low water-solubility. In order to overcome these issues, both chemical tuning and pharmaceutical formulation combined with tumor targeting strategies were applied. These aspects will be developed in this review for the most extensively studied Pcs during the last 25 years, i.e., aluminium-, zinc- and silicon-based Pcs.
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