The role of the mite Orthogalumna terebrantis in the biological control programme for water hyacinth, Eichhornia crassipes, in South Africa
- Authors: Marlin, Danica
- Date: 2011
- Subjects: Water hyacinth -- Biological control -- South Africa Aquatic weeds -- South Africa Invasive plants -- South Africa Mites -- South Africa Mites as biological pest control agents -- South Africa Biological pest control agents -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5762 , http://hdl.handle.net/10962/d1005450
- Description: Water hyacinth (Eichhornia crassipes) is an aquatic macrophyte originating from the Amazon basin. Due to its beautiful appearance it has been introduced into numerous countries across the world as an ornamental pond plant. It was introduced into South Africa in the early 1900s and has since reached pest proportions in many of the country’s fresh water bodies, causing significant economic and ecological losses. It is now considered to be the worst aquatic weed in South Africa. Efforts to control the spread of the weed began in the early 1970s and there have been some successes. Biological control has been used widely as an alternative to mechanical and chemical controls because it is cost-effective, self-sustaining and environmentally friendly. To date, six biological control agents have been introduced onto water hyacinth in South Africa. However, due to factors such as cold winter temperatures and interference from chemical control, the agent populations are occasionally knocked-down and thus the impact of biological control on the weed population is variable. In addition, many South African water systems are highly eutrophic, and in these systems the plant growth may be accelerated to such an extent that the negative impact of the agents’ herbivory is mitigated. One of the agents established on the weed is the galumnid mite Orthogalumna terebrantis, which originates from Uruguay. In South Africa, the mite was initially discovered on two water hyacinth infestations in the Mpumalanga Province in 1989 and it is now established at 17 sites across the country. Many biological control researchers believe that the mite is a good biological control agent but, prior to this thesis, little quantitative data existed to confirm the belief. Thus, this thesis is a post-release evaluation of O. terebrantis in which various aspects of the mite-plant relationship were investigated to determine the efficacy of the mite and thus better understand the role of the mite in the biological control programme of water hyacinth in South Africa. From laboratory experiments, in which mite densities were lower than densities occurring in the field, it was found that water hyacinth growth is largely unaffected by mite herbivory, except possibly at very high mite densities. When grown in high nutrient conditions the growth of the plant is so great that any affect the mite has is nullified. Plant growth is thus more affected by nutrients than by mite herbivory. However, mite feeding was also influenced by water nutrient levels and mite herbivory was greatest on plants grown in high nutrient conditions. The presence of the mite had a positive effect on the performance of the mirid Eccritotarsus catarinensis, such that the interactions of the two agents together had a greater negative impact on the plant’s growth than the individual agents had alone. Furthermore, water hyacinth physiological parameters, such as the plant’s photosynthetic ability, were negatively impacted by the mite, even at the very low mite densities used in the study. Plant growth rate is dependent on photosynthetic ability i.e. the rate of photosynthesis, and thus a decrease in the plant’s photosynthetic ability will eventually be translated into decreased plant growth rates which would ultimately result in the overall reduction of water hyacinth populations. In addition, temperature tolerance studies showed that the mite was tolerant of low temperatures. The mite already occurs at some of the coldest sites in South Africa. Therefore, the mite should be able to establish at all of the water hyacinth infestations in the country, but because it is a poor disperser it is unlikely to establish at new sites without human intervention. It is suggested that the mite be used as an additional biological control agent at sites where it does not yet occur, specifically at cold sites where some of the other, less cold-tolerant, agents have failed to establish. Finally, conditions of where, how many and how often the mite should be distributed to water hyacinth infestation in South Africa are discussed.
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The role of the principal as school leader in maintaining academic standards in the schooling of at-risk learners: a case study at a school in the northern areas of Port Elizabeth
- Authors: Draai, Karen Ann
- Date: 2011
- Subjects: School management and organization -- South Africa -- Port Elizabeth School principals -- South Africa -- Port Elizabeth Educational leadership -- South Africa -- Port Elizabeth School discipline -- South Africa -- Port Elizabeth Children with social disabilities -- South Africa -- Port Elizabeth Academic achievement -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1955 , http://hdl.handle.net/10962/d1008278
- Description: Many disadvantaged schools in South Africa are characterised by poor performance, which is often linked to the legacy of the apartheid regime. Yet, some disadvantaged schools are surviving and even producing excellent results. Many successful businessmen, politicians and academics can attest to the success of these schools, being a product of such schools. Leadership, which has received a lot of attention in recent years, are often the cause of schools failing to produce the expected results. Previous studies have shown that leadership is the key to academic excellence and that to lead disadvantaged schools to success requires strong leaders with moral purpose, who possess qualities of transformational leaders, but also leaders who can focus on instructional leadership practices. This study focuses on the role of leadership in maintaining academic standards at a school in the northern areas of Port Elizabeth. The school has a proud tradition of good academic performances and has even been labelled as a 'model C school in the northern areas'. It has been found that teachers are committed and hardworking and the principal is perceived as having expecting high expectations for the children of the area. He believes as an educator one should never give up on the children. The study found that the principal is a strong leader who shows characteristics of a transformational leader and has the drive of an instructional leader to lead the school and to maintain academic standards. He is a well-respected leader who leads with moral purpose and who has the desire to uplift the community. The study has the potential to provide guidance and encouragement to school principals, and to inform the Department of Education's leadership training programmes.
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The Role of Universities in a Transformed Post School Education and Training System
- Authors: Nzimande, Blade E
- Date: 2011
- Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education and state -- South Africa Education, Higher -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/762 , vital:19988
- Description: Over the past two years my Department has been conceptualising and building a single system comprising of all institutions involved in post-school education and training. The inevitable changes have affected some of the institutions and institutional types more than others, but it will inevitably affect all of them, I believe for the better. We are aiming at creating an integrated, accessible, flexible, differentiated and highly articulated system of post school education and training which will benefit our youth, our society more generally and our economy. This lecture talks to the role we see for universities in this transformed system.
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The short-term effect on shareholder wealth of banking mergers and acquisitions during periods of real economic expansion and contraction
- Authors: Kerr, Gordon Roy
- Date: 2011
- Subjects: Bank mergers , Consolidation and merger of corporations , Business cycles , Corporations -- Investor relations , Stockholder wealth , Rate of return
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1108 , http://hdl.handle.net/10962/d1013442
- Description: Controversy currently exists over whether abnormal returns (ARs) are earned by shareholders of bidder and target banks through a Merger and Acquisition (M&A). The state of the economy in which the firms operate is often mentioned as a reason for firms engaging in M&As, however, the extent to which economies influence the ARs of shareholders is unknown. Following MacKinlay (1997), the aim of this study is to determine the average ARs earned or lost by shareholders of several banks around the world during an M&A. The results obtained may indicate that shareholders of bidding firms consider an M&A to be a wealth-destroying event irrespective of the state of the economy. It would seem that target firms’ shareholders consider M&As to be wealth-creating events when they occur during a period of real economic expansion. However, during periods of real economic contraction, target firms’ shareholders consider M&As to be wealth-destroying events. Thus, the state of an economy during an M&A can affect average ARs considerably.
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The spatial evolution of the chemotaxis proteins of the Bacillus subtilis group
- Authors: Yssel, Anna Elizabeth Johanna
- Date: 2011
- Subjects: Chemotaxis , Bacillus subtilis , Bacillus (Bacteria) , Homology (Biology) , Plants -- Microbiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4027 , http://hdl.handle.net/10962/d1004087 , Chemotaxis , Bacillus subtilis , Bacillus (Bacteria) , Homology (Biology) , Plants -- Microbiology
- Description: The aim of this work was to study spatial evolution of the chemotaxis proteins of a group of plant-associated soil-dwelling bacteria vernacularly referred to as the B. subtilis group. This was achieved by creating homology models for the chemotaxis proteins if a suitable template was available, and by analysing the selective forces (positive, purifying or neutral) acting upon the chemotaxis proteins. Chemotaxis is the phenomenon in which bacteria direct their movement towards more favourable conditions, and is critical for processes such as obtaining nutrients, escaping toxic compounds, host colonization and bio-film formation. Members of the B. subtilis group exhibit different preferences for certain host plants, and it is therefore feasible that their chemotactic machinery are fine-tuned to respond optimally to the conditions of the various niches that the strains inhabit. Homology models were inferred for the plant growth promoting B. amyloliquefaciens FZB42 proteins CheB, CheC, CheD, CheR, CheW and CheY. The interactions between: CheC-CheD, the P1 and P2 domains of CheA with CheY and CheB, and the P4 and P5 domains of CheA with CheW were also modelled. The hydrophobic interactions contributing to intra- and inter-protein contacts were analysed. The models of the interactions between CheB and the various domains of CheA are of particular interest, because to date no structures have been solved that show an interaction between a histidine kinase (such as CheA) and a multidomain response regulator (such as CheB). Furthermore, evidence that phospho-CheB may inhibit the formation of phospho-CheY by competitively binding to the P2 domain of CheA is also presented. Proteins were analysed to determine if individual amino acid sites are under positive, neutral or purifying selection. The Methyl Accepting Chemotaxis Proteins (MCPs), CheA and CheV were also analyzed, but due to a lack of suitable templates, no homology models were constructed. Site-specific positive and purifying selection were estimated by comparing the ratios of non-synonymous to synonymous substitutions at each site in the sequences for the chemotaxis proteins as well as for the receptors McpA, McpB, and McpC. Homology models were coloured according to intensity of selective forces. It was found that the chemotaxis proteins of member of the B. subtilis group are under strong evolutionary constraints, hence it is unlikely that positive selection in these proteins are responsible for the differences in habitat preference that these organism exhibit.
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The strategic management of intellectual capital : a case study in the banking and financial services sector in Zambia
- Authors: Banda, Japhet Mathias
- Date: 2011
- Subjects: Intellectual capital -- Management , Intellectual capital -- Zambia , Banks and banking -- Zambia , Financial services industry -- Management -- Zambia
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1178 , http://hdl.handle.net/10962/d1002795 , Intellectual capital -- Management , Intellectual capital -- Zambia , Banks and banking -- Zambia , Financial services industry -- Management -- Zambia
- Description: Fundamental changes in the global economy are changing the basis of organisational competitive advantage. The challenge in attaining a competitive advantage is characterised by factors such as increased competition, market volatility, geographically dispersed operations, customer awareness, raising workforce diversity and stringent regulatory regimes. These factors have driven, and in turn have been driven by, an increasing complexity of products, services and the processes that create value, resulting in changes in the structural and functional dimensions of the organisation. Business executives and academics recognise the shift in value creating assets from the traditional land, labour and capital to intangible assets such as knowledge and information becoming the most important resources an organisation can muster.The combination and integration of intangible assets such as human resources, structural and relational resources has been grouped under the umbrella of intellectual capital. This study comprises of a single descriptive case study analysis to ascertain how intellectual capital is managed strategically to gain a competitive advantage in an organisation in the banking and financial services sector in Zambia. Based on document review and semi-structured interviews, this thesis investigated the extent to which an organisation in the banking and financial services sector in Zambia leveraged intellectual capital to gain competitive advantage. In this study it was found that there is a low level appreciation of the intellectual capital phenomenon as a strategic management tool in the participating organisation. However, the organisation has adopted aspects of intellectual capital and has implemented them successfully accounting for the organisation‘s competitive edge in the market.
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The synthesis and fluorescence behaviour of new unsymmetrically mono-functionalized carboxy Ge, Ti and Sn phthalocynines
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246977 , vital:51534 , xlink:href="https://doi.org/10.1016/j.dyepig.2011.03.026"
- Description: This work reports on the synthesis and fluorescence behaviour of novel unsymmetrically substituted monocarboxy germanium ((OH)2GeMCPc, 3), titanium (OTiMCPc 4) and tin ((ac)2SnMCPc, 5) phthalocyanines. The fluorescence quantum yields ranged from 0.09 to 0.14. The fluorescence lifetimes were found to be higher for the complex with higher fluorescence quantum yield value. Higher fluorescence quantum yields and lifetimes were obtained for the (ac)2SnMCPc complex (5), followed by OTiMCPc complex (4), and the lowest fluorescence quantum yield and lifetime were observed for (OH)2GeMCPc (3).
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The synthesis and photophysical properties of peripherally and non-peripherally substituted ball-type Mg (II) and Zn (II) phthalocyanines
- Authors: Canlica, Mevlude , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248417 , vital:51684 , xlink:href="https://doi.org/10.1039/C0DT00920B"
- Description: Newly synthesized ball-type Zn(II) and Mg(II) phthalocyanines containing four 1,1′-binaphthol substituents at peripheral and non-peripheral positions are presented. The structures of the synthesized compounds were characterized by using elemental analysis, UV-vis, FT-IR, 1H-NMR and mass spectroscopies. The ΦF values were 0.33, 0.08, 0.20 and 0.08 for 6–9, respectively. The ΦT values were 0.56, 0.85, 0.64 and 0.88 for 6–9, respectively. All the complexes showed reasonably large triplet lifetimes with τT values of 710 (6), 170 (7), 1490 (8) and 380 μs (9) in DMSO. These complexes offer potential as photosensitizers in photodynamic therapy.
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The teaching of mathematics in multigrade classrooms at the upper primary phase in selected Namibian schools
- Authors: Kapenda, Loide Ndakondjelwa
- Date: 2011
- Subjects: Mathematics -- Study and teaching -- Namibia Education, Elementary -- Namibia Combination of grades -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1796 , http://hdl.handle.net/10962/d1003681
- Description: The Namibian curriculum favours knowledge with understanding and application of knowledge and skills, because facts that are learned with understanding are easier to remember. This made learners to be able to represent mathematical situations in different ways and for different purposes. It also motivates teachers to contextualise the content to make mathematics teaching and learning more interesting and enjoyable to teachers and learners. However, some mathematics teachers are challenged by being required to teach multigrade classes, due to a massive response to improved access to education.Multigrade teaching is seen as a difficult practice especially when teachers are not well prepared to teach combined grades. This case study focused on the teaching of mathematics at Upper Primary Phase. An Interpretive paradigm was used to understand the teachers’ experiences and their teaching ethods. Hence the study aimed to investigate how teachers deliver their mathematics lessons in multigrade classrooms, considering the good practices and challenges that may occur. The findings revealed that teachers mostly use their monograde pedagogical knowledge,resulting in using quasi-monograde with a common timetable approach when teaching mathematics in multigrade settings. Although learners have access to the common mathematics syllabus, the quality of teaching the subject in multigrade classrooms seems to be affected due to the lack of teacher training in multigrade teaching. Also, equity and democracy need to be considered more than it currently is in terms of resource distribution to multigrade schools. Good practice of multigrade teaching existed in building on lower grade competencies, introducing lessons with common activities, as well as the concentration on lower grades which make learners independent. However, insufficient time, lack of knowledge in multigrade and curriculum knowledge in particular seem to challenge teachers and learners. Therefore, multigrade teachers need to be part of curriculum development for them to master the syllabus. These teachers will assist in developing multigrade resources for integration, contextualisation and more enrichment activities for high achievers.
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The unstable earth landscape and language in Patrick White's Voss, Michael Ondaatje's The English Patient and David Malouf's An Imaginary Life
- Authors: Lee, Deva
- Date: 2011
- Subjects: White, Patrick, 1912-1990. Voss Ondaatje, Michael, 1943- The English patient Malouf, David, 1934- An imaginary life Language and languages in literature English fiction -- 20th century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2238 , http://hdl.handle.net/10962/d1002281
- Description: This thesis argues that Patrick White’s Voss, Michael Ondaatje’s The English Patient and David Malouf’s An Imaginary Life depict landscape in a manner that reveals the inadequacies of imperial epistemological discourses and the rationalist model of subjectivity which enables them. The study demonstrates that these novels all emphasise the instabilities inherent in imperial epistemology. White, Ondaatje and Malouf chart their protagonists’ inability to comprehend and document the landscapes they encounter, and the ways in which this failure calls into question their subjectivity and the epistemologies that underpin it. One of the principal contentions of the study, then, is that the novels under consideration deploy a postmodern aesthetic of the sublime to undermine colonial discourses. The first chapter of the thesis outlines the postcolonial and poststructural theory that informs the readings in the later chapters. Chapter Two analyses White’s representation of subjectivity, imperial discourse and the Outback in Voss. The third chapter examines Ondaatje’s depiction of the Sahara Desert in The English Patient, and focuses on his concern with the ways in which language and cartographic discourse influence the subject’s perception of the natural world. Chapter Four investigates the representation of landscape, language and subjectivity in Malouf’s An Imaginary Life. Finally, then, this study argues that literature’s unique ability to acknowledge alterity enables it to serve as an effective tool for critiquing colonial discourses.
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The use of experimental design in the development of an HPLC–ECD method for the analysis of captopril
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184056 , vital:44163 , xlink:href="https://doi.org/10.1016/j.talanta.2010.11.025"
- Description: An accurate, sensitive and specific high performance liquid chromatography–electrochemical detection (HPLC–ECD) method that was developed and validated for captopril (CPT) is presented. Separation was achieved using a Phenomenex® Luna 5 μm (C18) column and a mobile phase comprised of phosphate buffer (adjusted to pH 3.0): acetonitrile in a ratio of 70:30 (v/v). Detection was accomplished using a full scan multi channel ESA Coulometric detector in the “oxidative-screen” mode with the upstream electrode (E1) set at +600 mV and the downstream (analytical) electrode (E2) set at +950 mV, while the potential of the guard cell was maintained at +1050 mV. The detector gain was set at 300. Experimental design using central composite design (CCD) was used to facilitate method development. Mobile phase pH, molarity and concentration of acetonitrile (ACN) were considered the critical factors to be studied to establish the retention time of CPT and cyclizine (CYC) that was used as the internal standard. Twenty experiments including centre points were undertaken and a quadratic model was derived for the retention time for CPT using the experimental data. The method was validated for linearity, accuracy, precision, limits of quantitation and detection, as per the ICH guidelines. The system was found to produce sharp and well-resolved peaks for CPT and CYC with retention times of 3.08 and 7.56 min, respectively. Linear regression analysis for the calibration curve showed a good linear relationship with a regression coefficient of 0.978 in the concentration range of 2–70 μg/mL. The linear regression equation was y = 0.0131x + 0.0275. The limits of detection (LOQ) and quantitation (LOD) were found to be 2.27 and 0.6 μg/mL, respectively. The method was used to analyze CPT in tablets. The wide range for linearity, accuracy, sensitivity, short retention time and composition of the mobile phase indicated that this method is better for the quantification of CPT than the pharmacopoeial methods.
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The use of learning support materials in the rural schools of Maputaland, Kwa-Zulu Natal
- Authors: Van der Merwe, Michelle
- Date: 2011
- Subjects: Environmental education -- South Africa -- Maputaland African Coelacanth Ecosystem Programme Coelacanthiformes -- South Africa -- Maputaland Teaching -- Aids and devices -- South Africa -- Maputaland Environmental education -- Curricula -- South Africa -- Maputaland
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1815 , http://hdl.handle.net/10962/d1003701
- Description: The African Coelacanth Ecosystem Programme (ACEP) was established in 2002 after the discovery of a colony of coelacanths off the Maputaland coast at Sodwana Bay, KwaZulu Natal. The environmental education and awareness sub-programme developed learning support materials (LSM's) for use in schools and the materials were disseminated annually through teacher education workshops. This study aimed to uncover the use of these LSM's in the rural schools of Maputaland. The active learning framework was used to analyse the materials. Collectively, the ACEP materials cover a range of active learning aspects; however alignment with the curriculum has resulted in an increased focus on experiments, accompanied by a loss of environmental content and a narrowing scope for active environmental learning. Workshop questionnaires and four school case studies revealed the patterns of practice of use of materials in schools. The stated use of materials by teachers is not fully realized in the actual classroom practice which centres on learning content and concept definitions. There is no culture of use of materials in the schools following the annual introduction of ACEP materials. It was also found that the marine and coastal knowledge holding power is outside the realm of the teachers' practice and control. The findings of this study come at a time when there is uncertainty over the future of South African education and the curriculum. This research may inform the environmental education and coastal and marine education field as to their role in education and more specifically the development of learning support materials.
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The xfn connection management and control protocol
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427137 , vital:72417 , https://www.aes.org/e-lib/browse.cfm?elib=16143
- Description: With the advent of digital networks that link audio devices, there is a need for a protocol that integrates control and connection management, enables the streaming of all media content such as audio and video between devices from different manufacturers, and that provides a common approach to the control of these devices. This paper describes such a protocol, named XFN, currently being standardized as part of the AES X170 project. XFN is an IP-based peer to peer network protocol, in which any device on the network may send or receive connection management, control, and monitoring messages. Essential to the XFN protocol is the fact that each parameter in a device can be addressed via a hierarchical structure that reflects the functional layout of the device.
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The zoogeography of the cetaceans in Algoa Bay
- Authors: Melly, Brigitte Leigh
- Date: 2011
- Subjects: Cetacea -- South Africa -- Algoa Bay , Cetacea -- Behavior -- South Africa -- Algoa Bay , Cetacea -- South Africa -- Algoa Bay -- Geographical distribution , Cetacea -- Counting -- South Africa -- Algoa Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4858 , http://hdl.handle.net/10962/d1005534 , Cetacea -- South Africa -- Algoa Bay , Cetacea -- Behavior -- South Africa -- Algoa Bay , Cetacea -- South Africa -- Algoa Bay -- Geographical distribution , Cetacea -- Counting -- South Africa -- Algoa Bay
- Description: The most recent study on cetaceans in Algoa Bay, South Africa, was conducted over 14 years ago. Consequently, knowledge of the cetacean species visiting this bay is currently based on incidental observations and stranding data. A number of developments in recent years: a deepwater port, proposed oil refinery, increased boating and fishing (commercial and recreational), a proposed Marine Protected Area, and the release of a whale-watching permit, all of which may impact these animals in some way, highlight the need for a baseline study on cetaceans. Therefore, the aim of this study was to determine the spatial and temporal distribution, and habitat preference of cetaceans in Algoa Bay. Boat-based surveys were conducted monthly between March 2009 and July 2010. At each sighting the GPS location, species, group size and composition, and behaviour were recorded. Using GIS, the sighting data was related to data layers of geographical variables such as sea surface temperature, depth and sea-floor substrate. Approximately 365 hours of search effort were completed over 57 surveys, with a total of 346 sightings. Species observed were: southern right whales (Eubalaena australis), humpback whales (Megaptera novaeangliae), Bryde’s whales (Balaenoptera brydei), Indian Ocean bottlenose dolphins (Tursiops aduncus), Indo-Pacific humpback dolphins (Sousa chinensis), and longbeaked common dolphins (Delphinus capensis). Southern right whales were observed during austral winter, utilising the shallow, protected areas of the bay as a mating and nursery ground. Humpback whales were also recorded extensively during winter, in more offshore waters, with a significant number of mother-calf pairs sighted. Bryde’s whales were recorded in offshore waters during summer and autumn, where they were primarily observed travelling and foraging. Bottlenose dolphins were the most prolific species sighted. They were recorded year-round throughout the inshore waters of the bay, with large group sizes (up to 500 animals), and displayed a wide variety of behaviours. Humpback dolphins were observed in extremely shallow and inshore waters (mean bottom depth of 6.6 m) along the south-west corner of the bay, in small groups of approximately three individuals. Common dolphins were the least observed species, and were mainly observed foraging in large groups of up to 800 individuals. The results of this study indicate how cetaceans utilise the bay in significantly different ways. Geographical and anthropogenic factors have influenced the spatial and temporal distribution of these animals and have resulted in habitat preferences, as well as potential key habitats, in the bay. Thus, this study has provided baseline information for future research and for better informed conservation and management strategies in Algoa Bay.
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The ‘refeudalisation’ or the ‘return of the repressed’ of the public sphere?:
- Authors: Garman, Anthea
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159857 , vital:40350 , DOI: 10.1080/02560054.2011.621293
- Description: The prevalent depiction of the heyday of the public sphere and its fall from grace under present-day, publicity-ridden, highly commercialised media, with their individualised address of entertainment, is an inadequate conception of today's complex public spheres. The 18th-century bourgeois public sphere had a number of features – often repressed in practice and in theory – which were bound to have their outcomes and a/effects in the public spaces, practices and vehicles we experience today.
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Theiler’s murine encephalomyelitis virus infection induces a redistribution of heat shock proteins 70 and 90 in BHK-21 cells, and is inhibited by novobiocin and geldanamycin:
- Authors: Mutsvunguma, Lorraine Z , Moetlhoa, Boitumelo , Edkins, Adrienne L , Luke, Garry A , Blatch, Gregory L , Knox, Caroline M
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165085 , vital:41207 , DOI: 10.1007/s12192-011-0262-x
- Description: Theiler’s murine encephalomyelitis virus (TMEV) is a positive-sense RNA virus belonging to the Cardiovirus genus in the family Picornaviridae. In addition to other host cellular factors and pathways, picornaviruses utilise heat shock proteins (Hsps) to facilitate their propagation in cells. This study investigated the localisation of Hsps 70 and 90 in TMEV-infected BHK-21 cells by indirect immunofluorescence and confocal microscopy. The effect of Hsp90 inhibitors novobiocin (Nov) and geldanamycin (GA) on the development of cytopathic effect (CPE) induced by infection was also examined. Hsp90 staining was uniformly distributed in the cytoplasm of uninfected cells but was found concentrated in the perinuclear region during late infection where it overlapped with the signal for non-structural protein 2C within the viral replication complex.
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Towards a critical understanding of media assistance for "new media" development
- Authors: Mathurine, Jude
- Date: 2011
- Subjects: Mass media -- Technological innovations , Mass media -- Political aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3459 , http://hdl.handle.net/10962/d1002914 , Mass media -- Technological innovations , Mass media -- Political aspects
- Description: The field of media assistance has grown ever more complex with the inclusion of ‘new media’ networks, channels, tools and practices (such as the Internet, satellite television, mobile devices, social media and citizen journalism) to the media development mix. Adding to the ferment is the increasing convergence between the formerly discrete terrains of ICT for development, media for development and (mass) media development. Much of the discussion regarding the utility and objectives of media development in general and ‘new media’ in particular has been viewed through a modernist and techno-determinist prism which offers a limited ideological view of media development and its objects and consequently, a limited set of communication approaches and strategies. This study contextualises the assumptions of media development historically and critically, with particular focus on new media’s roles and relationships with the media environment, and its objectives democratisation and development. Through the application of literature, theory and various research studies, this thesis establishes a broader view of new media’s role and diverse consequences for media development, democracy and development. The study recommends greater collaboration, contextual research and theorisation of media development and new media as part of mixed media systems and cognisant of the multi-dimensional natures of its objects of democracy and development. One implication is the need for professionalisation of the media development and media assistance sector. In relation to the influences of new media on media use and the media as an institution, it motivates the need to address digital divides and emphasise the sustainability of the practice of journalism.
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Towards a standard model for networked audio devices
- Authors: Eales, Andrew , Foss, Richard
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427151 , vital:72418 , https://www.aes.org/e-lib/online/browse.cfm?elib=16144
- Description: Different control protocols for networked audio devices typically emphasize particular aspects of a device, such as the representation of parameter data, or a representation of the functional structure of a device. A sophisticated device model must represent parameter data, device structure and the visual presentation of controls. Parameter data should be related to the device structure, while also being represented within a flexible, logical hierarchy. The development of a standard device model is proposed and discussed with reference to the OSC, IEC62379, ACN and X170 control protocols. This abstract model is independent of any specific control protocol, and provides support for interoperability between control protocols. The proposed model is also discussed within the context of an object-based approach to service enumeration and control using an associative, shared memory model.
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Towards a sustainable bioprocess for the remediation of acid mine drainage
- Authors: Mambo, Mutsa Prudence
- Date: 2011
- Subjects: Acid mine drainage , Algae culture , Reduction (Chemistry) , Hydrolysis , ASPAM model (Acid mine drainage) , Water -- Purification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5955 , http://hdl.handle.net/10962/d1006167 , Acid mine drainage , Algae culture , Reduction (Chemistry) , Hydrolysis , ASPAM model (Acid mine drainage) , Water -- Purification
- Description: Acid mine drainage is of growing concern for both developing and developed economies. Thus there is increasing pressure to develop alternative remediation strategies. Biological sulphidogenic mechanisms have long since been studied but, very few have been implemented on a large scale. Limitations are due to the inability to acquire a suitable, low cost, environmentally friendly, renewable carbon source. The present study investigated the use of an algae biomass generated by the HRAOP of an IAPS as a carbon source for the EBRU 00AB/06 SRB consortium. The algae biomass and consortium were utilized together to remediate simulated AMD. Remediation involved decreasing the sulphate and metal concentrations in solution and decreasing the acidity of a simulated AMD. Experiments were carried out to investigate the capability of the EBRU 00AB/06 SRB consortium for sulphate reduction and sulphide generation. The consortium produced colonies when grown under anaerobic conditions in Petri dishes containing modified lactate SRB medium. The SRB consortium reduced the sulphate concentration of modified Postgates medium B and generated sulphide. Further analysis of the EBRU 00AB/06 SRB consortium revealed that the consortium was minimally impacted at pH 5 and by sulphate and iron at 3 g.L-1 and 0.5 g.L-1 respectively. The EBRU 00AB/06 SRB consortium was exposed to Actinomycin D and Ethidium Bromide to determine whether transcription and translation of proteins was required for sulphate reduction. Results indicated that sulphide generation and sulphate reduction were inducible. Analysis of the algae biomass used in this study revealed the empirical formula C1.0H1.91N0.084S0.003O0.36 indicating a carbon source rich in the nutrients required to sustain microbial development. Light microscopy revealed that algae cell walls and in particular those of Pediastrum were susceptible to acid hydrolysis. Dinitrosalicylic acid, Nile red, Bradford and Ninhydrin assays were used to determine the reducing sugar, lipid, protein and amino acid content respectively, of the mixed algae biomass. Results showed that upon exposure of the biomass to simulated AMD at pH 1 and pH 3, the concentration of reducing sugars and amino acids in solution increased. Whereas levels of lipids remained unchanged while the protein concentration decreased, indicating that, upon exposure of algae biomass to AMD, simulated or otherwise, cells ruptured, proteins were hydrolyzed and polysaccharides were broken down to sugars which are immediately available for SRB utilization. Exposure of biomass to simulated AMD revealed further that the presence of algae biomass increased the pH of simulated AMD (pH 3) to pH 7.67 after 4 d. Likewise, the pH of simulated AMD at 1 increased to 1.77 after 2 d while pH of the neutral control increased to 8.1 after 4 d. A direct comparison between lactate and algae biomass revealed 94 % sulphate removal after 23 d in the presence of algae biomass while 82 % sulphate removal was measured in the presence of lactate. Thus the EBRU 00AB/06 SRB consortium successfully utilized algae biomass for sulphate reduction and sulphide generation. In another experiment to establish if the consortium could remediate simulated AMD (pH 5) containing 0.5 g.L-1 iron and 3 g.L-1 sulphate while utilizing an algae biomass as the carbon source no residual iron was detected after 14 d and by day 23, an 89.07 % reduction in sulphate was measured. The results of this investigation are discussed in terms of utilizing a readily available and renewable biomass in the form of microalgae produced in HRAOPs as an effective carbon source in the SRB catalysed remediation of AMD.
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Towards monitoring that makes sense : action research design of a planning, learning and accountability system for a sustainable agriculture programme in Eastern Indonesia
- Authors: Deprez, Stefan Gert Marie
- Date: 2011
- Subjects: Agricultural development projects -- Indonesia Agricultural administration -- Monitoring -- Indonesia Action research -- Case studies Action research in education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1801 , http://hdl.handle.net/10962/d1003686
- Description: This study is an account of an action research process to develop a planning, learning and accountability (PLA) system for the sustainable agriculture chain development programme of VECO (Vredeseilanden Country Office) Indonesia. Many monitoring and evaluation (M&E) processes in development programmes are largely carried out to provide information for funding agencies, to meet external accountability requirements and for symbolic protection. This study generates insights into an integrated, learning-oriented monitoring practice which fosters reflective practice, provides feedback to programme stakeholders about performance, progress and results achieved, facilitates improved accountability, and generates information and knowledge useful for the programme stakeholders to take decisions for improved action. It is argued that M&E systems have the potential, if developed well, to serve as a framework or ‘carrier’ for organisational and institutional learning – an essential requirement to respond to the complex nature of development processes. Outcome mapping is presented as a possible approach to be used as the basis for such a M&E system. This study was underpinned by a socially critical orientation to development (programmes) and by an action research method to guide the PLA system design process. The design process was organized around seven steps - which in themselves were a result of the action research process – including specific steps to ensure a learning-oriented M&E system. Based on the agreed purposes and intended uses of the monitoring and learning process, the resulting PLA system is focused around the organizational spaces and rhythms of VECO Indonesia which are central to sharing, debate, learning and decision-making. In this way, the PLA system becomes integral to the thinking and doing of the organization. It is built on the premise that monitoring does not end with gathering data; it also needs to include a process of understanding and deciding how data can best be used and analysed to strengthen concerted action and facilitate decision-making. It highlights the importance of sense-making – interpreting information to make it usable for action. Furthermore, it incorporates an approach to assess and consciously plan for the creation of the necessary organisational conditions to implement and maintain a learning-oriented M&E system. The study is completed by critical reflection on the relevance of VECO’s new PLA system for planning, learning and accountability, combined with the use of a future scenario technique to generate recommendations and identify critical future directions. Further exploration of ‘intelligent’ information-seeking methods and processes is called for; and a practice which moves beyond intra-organisational monitoring – focusing on VECO’s own monitoring needs – towards a monitoring process that facilitates change based on the viewpoints of, and in collaboration with local actors, i.e., institutional monitoring and learning, is recommended. VECO is encouraged to continue developing a mindset and practice whereby the programme team and partners have the ability to leave the safe zone of pre-determined outcomes and actions, and to make sense of the world as they engage in action.
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