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An evaluation of appreciative inquiry as an alternative organisation development approach

  • Authors: Van der Merwe, Schalk Willem
  • Date: 2017
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: http://hdl.handle.net/10962/5925 , vital:20990
  • Description: The research provides an insight into the main challenges of previous Organisation Development processes, and Appreciative Inquiry is explored to establish the value it can offer as an alternative which minimises these challenges in today’s organisations. Organisation Development originated during the early 1950s and has evolved, adapted and changed dramatically since then. Two classical Organisation Development processes, Lewin’s 3-Step model and the Action Research spiral, are described, and typical challenges of applying them in today’s organisations are outlined. To remain competitive, organisations need to identify, adjust, and adapt to changing circumstances. These changing circumstances are constant and are due to increasingly complex demands from technological, economic, managerial, and cultural needs. Appreciative Inquiry as an approach is explored as an alternative Organisation Development process: it shifts the question from ‘what is going wrong’ to ‘what is going right in the organisation’. Appreciative Inquiry consists of the Discovery, Dream, Design and Destiny stages, and searches for the best in people and their organisations. In accordance with the constructionist paradigm, the research offers conclusions through the confirmation of past practices, conversations and relationships combined with creative new methods or experimentation of a positive intended future. The One- Group Pretest-Posttest, as a design, was selected to explore the effect of the variable (the Appreciative Inquiry intervention) in relation to the pre- and post-experimental evaluation. The design consists of an initial engagement (Pretest), the influencing variable (an Appreciative Inquiry intervention) and final engagement (Posttest) with the same group. The research was supported by a mixed method approach, with qualitative data supported by quantitative data. The quantitative data provided a general understanding of how participants experienced the change interventions. The qualitative data provided the information on how respondents experienced Organisation Development before an Appreciative Inquiry intervention and their views after an Appreciative Inquiry intervention. A South African secondary school was selected as a research site. Limited research is available regarding the application of Organisation Development and especially Appreciative Inquiry as a process in schools in general, and in South African schools in particular. A survey questionnaire was the instrument for collecting the quantitative data regarding the participants’ biographical information and change process perceptions. For the collection of qualitative data, interview questionnaires were used. The findings indicate that whereas previous change processes appear to have regarded the various staff levels of the school as separate entities, during the Appreciative Inquiry approach all staff were included as being an integral part of the organisation. The main finding after completion of the Appreciative Inquiry intervention was that collectively discussing and defining issues in a positive light instead of a problem to be solved changes the perspective of participants. Through the application of the Appreciative Inquiry’s four stages, participants were invited to think in a new way by applying innovation, enhancing participation, maintaining a positive core, and providing practical solutions through provocative statements. Conclusions reached from the research are that Appreciative Inquiry is a viable alternative for minimising Organisation Development challenges in contemporary organisations. The conclusions are based on factors such as understanding the reason for change; strong leadership; defining what is a successful intervention; understanding the Appreciative Inquiry process, the value of provocative statements; and the sustainability of change.
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Community structure and trophic ecology of shallow and deep rocky reefs in a well-established marine protected area

  • Authors: Heyns, Elodie R
  • Date: 2016
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/54438 , vital:26565
  • Description: The now formally adopted ecosystem approach to fisheries (EAF) considers not only commercially important species, but the entire ecosystem and the processes that support these species. A key component of EAF management is the implementation of no-take Marine Protected Areas (MPAs). Shallow water fish stocks are depleted and fishing effort is moving deeper and further offshore to keep up with demands. This situation calls for a detailed investigation of deep nearshore reefs to provide critical information relevant to policy uptake and management decisions regarding existing and new MPAs in terms of zonation and use. To address this need, the aim of this thesis was to investigate reefs that lie between 45 and 75 m and compare them in terms of community structure and function to the relatively well-studied shallow reefs that lie within SCUBA diving depth (<25 m). Ecological collections were made in the centre of a large and well-established MPA, Tsitsikamma National Park, to ensure that data represented non-anthropogenically impacted communities. Data were collected from two study sites; Rheeders Reef, (shallow reef) and Middlebank, a deep reef complex situated near the Storms River Mouth. The first step to address the aim of this study was to obtain baseline data on the distribution patterns of both the macrobenthic invertebrates and fish assemblages. Baseline data were obtained by underwater video methods and included the use of a remotely operated vehicle, baited remote underwater stereo-video systems (stereo-BRUVs) and traditional underwater camera equipment operated by SCUBA divers. To establish functional differences between the two study sites, fatty acid (FA) and stable isotope (SI) analyses were employed. These biomarker techniques provided insight into the importance of different sources of primary production, nutritional condition and species packing. From 360 photoquadrats examined for macrobenthic invertebrate distribution patterns, 161 invertebrates were identified that demonstrated a clear changeover of species along the depth gradient. Species richness was highest on the shallow reef and decreased with an increase in depth. To understand how the measured environmental variables impacted the macrobenthic assemblage data a LINKTREE analysis was performed. LINKTREEs produce hierarchical cluster analysis based on the macrobenthic assemblage data and provide a threshold of environmental variables that correspond to each cluster. The outcome of the LINKTREE analysis indicated that the changeover of species resulted in four distinct clusters, each cluster associated with a particular set of environmental variables that fell within a depth range. On the shallowest sites, the high energy environment resulting from wave action and surge prevented the settlement of suspended particles. The high energy environment of the shallow reef selected for low-growing encrusting species. High light intensities supported great abundances of benthic algae, and as light was lost with increasing depth, algal cover gradually diminished until it was completely absent on the deep reef. The reduced impact of surface wave action on the deep reef caused increased levels of settled suspended particles. The high levels of settled particles likely caused clogging of feeding parts of the encrusting species. Consequently, upright growth forms were more common in the lower energy environment of the deep reef. A total of 48 fish species were identified from 51 stereo-BRUVs samples. Fish assemblages differed significantly between the shallow and deep reefs. The shallowest sites were characterised by many small and juvenile fish species that fed at lower trophic levels. The deep reef supported the majority of the large predatory fish that fed at higher trophic levels. Many species demonstrated depth-related ontogenetic shifts in habitat use, and as such the deep reef hosted the majority of the sexually mature individuals. The fish assemblages also demonstrated a strong association with the macrobenthic clusters identified as habitat types by the LINKTREE analysis. The results from 201 FA and 191 SI samples provided information on specific feeding interactions, but more importantly shed some light on different processes that supported the shallow and deep reef communities. The shallow reef community was characterised by greater diversity of food sources, a pattern that could be explained by the presence of benthic algae and terrestrial inputs. Greater diversity of carbon sources at the bottom of the food web meant that a larger variety of species could be supported. Higher species richness increased the number of distinct taxa that performed similar functions, rendering the shallow reef more redundant and consequently more resilient to disturbance. In contrast, the deep reef demonstrated a food web supported mainly by pelagic production, which was more variable both over space and time. The deep reef was less redundant when compared to the shallow reef, as fewer species demonstrated similar trophic niches. These factors, in addition to the increased presence of sensitive calcareous macrobenthic species on the deep study site, rendered the deep reef more vulnerable to disturbance when compared to the shallow reef. Although the data presented here were from a single study area, the limitations typically associated with these inaccessible and challenging sampling environments made the dataset a significant contribution to the knowledge of reef ecosystems. The study addressed priority research questions for South Africa as identified during the National Biodiversity Assessment. The observable differences in structure, function and vulnerability point to the need for continued protection of our shallow reefs and offshore expansion of our MPA networks. Future research should determine if the patterns identified here are common throughout the Agulhas Ecoregion to provide managers with robust evidence for the extension our MPAs offshore.
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A small town in the early apartheid era: A history of Grahamstown 1946-1960 focusing on "White English" perspectives.

  • Authors: Lancaster, Rupert Giles Swinburne
  • Date: 2013
  • Subjects: Grahamstown (South Africa) -- History -- 20th Century , Grahamstown (South Africa) -- Politics and government -- 20th century , Grahamstown (South Africa) -- Social conditions -- 20th Century , Grahamstown (South Africa) -- Economic conditions -- 20th Century , Grahamstown (South Africa) -- Social life and customs -- 20th Century , Apartheid -- South Africa , Whites -- South Africa -- Grahamstown
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2612 , http://hdl.handle.net/10962/d1013161
  • Description: This Thesis examines the socio-political perceptions of Grahamstown, a small South African City, during the period 1946 to 1960. The ‘White English’ population of Grahamstown is the specific focus, as it formed the dominant social group during the period and consequently provided the majority of information for this work. During this period the majority of Grahamstowns ‘White English’ population thought of their City as holding many attractive features and experiences despite the slum-conditions and poverty that were rife in the Locations. During the British Royal Familie’s tour of the Union of South Africa in 1947, Grahamstown was one of the Cities visited. The loyalty that Grahamstown’s ‘White English’ citizens felt towards the Royal Family and the United Kingdom is explored in connection with the regard that ‘White English’ Grahamstown held for the 1820 Settlers. To highlight the Grahamstown City Council’s activities during this period five events are analysed: The Grahamstown Financial Crisis, The Grahamstown Housing Crisis, The Beer Hall Debate, The establishment of a Tuberculosis Hospital and the granting of Full University Status to Rhodes University College. It is shown, with regard to the politics of the period, that ‘White English’ Grahamstown, unequivocally supported the United Party and were vocally anti-Nationalist. The implementation of Apartheid policies within Grahamstown is explored, with specific focus placed upon the Group Areas Act. Finally the anti-republican sentiment espoused by ‘White English’ Grahamstown is reviewed.
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Polymer based electrospun nanofibers as diagnostic probes for the detection of toxic metal ions in water

  • Authors: Ondigo, Dezzline Adhiambo
  • Date: 2013
  • Subjects: Heavy metals , Nanofibers , Nanoparticles , Colorimetric analysis
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4557 , http://hdl.handle.net/10962/d1018261
  • Description: The thesis presents the development of polymer based electrospun nanofibers as diagnostic probes for the selective detection of toxic metal ions in water. Through modification of the chemical characteristics of nanofibers by pre- and post-electrospinning treatments, three different diagnostic probes were successfully developed. These were the fluorescent pyridylazo-2-naphthol-poly(acrylic acid) nanofiber probe, the colorimetric probe based on glutathione-stabilized silver/copper alloy nanoparticles and the colorimetric probe based on 2-(2’-Pyridyl)-imidazole functionalized nanofibers. The probes were characterized by Fourier transform infrared spectroscopy (FTIR), Energy dispersive x-ray spectroscopy (EDX), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The fluorescent nanofiber probe was developed towards the determination of Ni²⁺. Covalently functionalized pyridylazo-2-naphthol-poly(acrylic acid) polymeric nanofibers were employed. The solid state Ni²⁺ probe exhibited a good correlation between the fluorescence intensity and nickel concentration up to 1.0 mg/mL based on the Stern-Volmer mechanism. The detection limit of the nanofiber probe was found to be 0.07 ng/mL. The versatility of the fluorescent probe was demonstrated by affording a simple, rapid and selective detection of Ni²⁺ in the presence of other competing metal ions by direct analysis without employing any sample handling steps. For the second part of the study, a simple strategy based on the in-situ synthesis of the glutathione stabilized silver/copper alloy nanoparticles (Ag/Cu alloy NPs) in nylon 6 provided a fast procedure for fabricating a colorimetric probe for the detection of Ni²⁺ in water samples. The electrospun nanofiber composites responded to Ni²⁺ ions but did not suffer any interference from the other metal ions. The effect of Ni²⁺ concentration on the nanocomposite fibers was considered and the “eye-ball” limit of detection was found to be 5.8 μg/mL. Lastly, the third probe was developed by covalently linking an imidazole derivative; 2-(2′-Pyridyl)-imidazole (PIMH) to Poly(vinylbenzyl chloride) (PVBC) and nylon 6 nanofibers by post-electrospinning treatments using a wet chemical method and graft copolymerization technique, respectively. The post-electrospinning modifications of the nanofibers were achieved without altering their fibrous morphology. The color change to red-orange in the presence of Fe²⁺ for both the grafted nylon 6 (white) and the chemically modified PVBC (yellow) nanofibers was instantaneous. The developed diagnostic probes exhibited the desired selectivity towards the targeted metal ions.
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Biological synthesis of metallic nanoparticles and their interactions with various biomedical targets

  • Authors: Sennuga, Afolake Temitope
  • Date: 2012
  • Subjects: Nanoparticles Biosynthesis Nanotechnology Biomineralization Morphology Ceruloplasmin Ribonucleases Adenosine triphosphatase Acetylcholinesterase Platinum Gold Silver
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4009 , http://hdl.handle.net/10962/d1004069
  • Description: The synthesis of nanostructured materials, especially metallic nanoparticles, has accrued utmost interest over the past decade owing to their unique properties that make them applicable in different fields of science and technology. The limitation to the use of these nanoparticles is the paucity of an effective method of synthesis that will produce homogeneous size and shape nanoparticles as well as particles with limited or no toxicity to the human health and the environment. The biological method of nanoparticle synthesis is a relatively simple, cheap and environmentally friendly method than the conventional chemical method of synthesis and thus gains an upper hand. The biomineralization of nanoparticles in protein cages is one of such biological approaches used in the generation of nanoparticles. This method of synthesis apart from being a safer method in the production of nanoparticles is also able to control particle morphology. In this study, a comparative biological synthesis, characterization and biomedical effects of metallic nanoparticles of platinum, gold and silver were investigated. Metallic nanoparticles were biologically synthesized using cage-like (apoferritin), barrel-like (GroEL) and non-caged (ribonuclease) proteins. Nanoparticles generated were characterized using common techniques such as UV-visible spectroscopy, scanning and transmission electron microscopy, inductively coupled optical emission spectroscopy, Fourier transform infra-red spectroscopy and energy dispersion analysis of X-rays (EDAX). Nanoparticles synthesised biologically using apoferritin, GroEL and RNase with exhibited similar chemical and physical properties as thoses nanoparticles generated chemically. In addition, the metallic nanoparticles fabricated within the cage-like and barrel-like cavities of apoferritin and GroEL respectively, resulted in nanoparticles with relatively uniform morphology as opposed to those obtained with the non-caged ribonuclease. The enzymatic (ferroxidase) activity of apoferritin was found to be greatly enhanced with platinum (9-fold), gold (7-fold) and silver (54-fold) nanoparticles. The ATPase activity of GroEL was inhibited by silver nanoparticles (64%), was moderately activated by gold nanoparticles (47%) and considerably enhanced by platinum nanoparticles (85%). The hydrolytic activity of RNase was however, lowered by these metallic nanoparticles (90% in Ag nanoparticles) and to a higher degree with platinum (95%) and gold nanoparticles (~100%). The effect of synthesized nanoparticles on the respective enzyme activities of these proteins was also investigated and the potential neurotoxic property of these particles was also determined by an in vitro interaction with acetylcholinesterase. Protein encapsulated nanoparticles with apoferrtin and GroEL showed a decreased inhibition of acetylcholinesterase (<50%) compared with nanoparticles attached to ribonuclease (>50%). Thus, it can be concluded that the cavities of apoferitin and GroEL acted as nanobiofactories for the synthesis and confinement of the size and shape of nanoparticles. Furthermore, the interior of these proteins provided a shielding effect for these nanoparticles and thus reduced/prevented their possible neurotoxic effect and confirmed safety in their method of production and application. The findings from this study would prove beneficial in the application of these nanoparticles as a potential drug/drug delivery vehicle for the prevention, treatment/management of diseases associated with these enzymes/proteins.
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An evaluation of the marketing and distribution channels of the Mzuzu Coffee Planters Cooperative Union (MZCPCU)

  • Authors: Jussa, Leman Abdulrazak Wyson
  • Date: 2011
  • Subjects: Mzuzu Coffee Planters Cooperative Union Coffee -- Marketing -- Malawi Marketing channels -- Evaluation -- Malawi Agricultural development projects -- Malawi
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:819 , http://hdl.handle.net/10962/d1008300
  • Description: Literature and the cooperative movement in Malawi shows that the first cooperative was established in 1947. Since the economy of the country depends on agriculture, most cooperatives were strongly developed in the fields of agricultural production, and processing and marketing. The first coffee cooperative was registered in 1950, known as the Nchenachena Coffee Producers Cooperative Society. After Malawi 's independence in 1964, agricultural cooperatives were dissolved and government formed the Farmers Marketing Board (FMB) to take over all marketing activities of all crops, including coffee. The FMB was replaced by the Agricultural Development and Marketing Corporation (ADMARC) in 1967. After the dissolution of agricultural cooperatives, government saw the need for crop development and established Smallholder Coffee Authority in 1971. The Smallholder Coffee Authority worked up to 1999 when it collapsed because of administrative and financial problems. Due to the failure of the Smallholder Coffee Authority, the government of Malawi reintroduced agricultural cooperatives in 1999. Mzuzu Coffee Planters ' Cooperative Union was formed in 2006 following the re-introduction of cooperatives. The union is mandated to promote sustainable production, processing and marketing of Arabica coffee on behalf of the farmers. Since its inception, the output of coffee for export from the Mzuzu Coffee Planters Cooperative Union has increased from 156 tonnes in 2006 to over 400 tonnes in 2009. The increase in coffee exports was not by mere chance but a number of factors contributed to this success. The main reasons for this success were: • Strong prior relationship between the growers and the buyers • The uniqueness of the cooperative business model • The unique taste and quality of coffee grown • The introduction of a different approach to farming coffee Currently there is high demand for organic coffee and this could be a niche market that is not only rewarded with premium prices but also creates environmental friendly business. The union considers Fair Trade market as an alternative approach to conventional trade, aiming at improving the livelihoods of smallholder producers by improving payments, giving them fair prices and providing continuity in trading relationships.
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The role of memory, museums and memorials in reconciling the past : the Apartheid Museum and Red Location Museum as case studies

  • Authors: Sippel, Elizabeth
  • Date: 2011
  • Subjects: Apartheid Museum (Johannesburg, South Africa) Red Location Museum (Port Elizabeth, South Africa) Atrocities -- Museums Apartheid and art Apartheid -- History Historical museums Collective memory Memorialization History -- Psychological aspects Memory (Philosophy) Museum exhibits -- Historiography Museums -- Historiography
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2440 , http://hdl.handle.net/10962/d1005773
  • Description: When South Africa became a democracy, many of its cultural institutions were tainted by the stigma of having been tools for the production and propagation of apartheid ideology. This thesis examines two key facets of post-apartheid museums and memorials. Firstly, how they have repositioned themselves as institutions of cultural and social standing. Secondly, their role as tools of nation building, social change, and creators of national collective memory within the new democratic South Africa. Through an analysis of cultural memory theory pertaining to museology, this study elaborates on the methods employed by museums to incorporate memory into their narratives and in turn, transfer collective memory to their viewers. This thesis provides a comparative study of the architectural, memorial and museological strategies of two post-apartheid museums; the Red Location Museum and the Apartbeid Museum. It examines the contributions of both museums to the introduction of new museological strategies for the successful creation and transmission of South African collective memory. Through this analysis, both the invaluable contributions and the drawbacks of post-apartheid museums as tools for the promotion of new democratic ideologies and philosophies are considered. This thesis does not resolve the arguments and questions which have surfaced regarding cultural institutions as tools for the promotion of reconciliation and the construction of national collective memory within South Africa. As the current climate of memorialisation is one of change and paradox, it is presently impossible to fully quantify post-apartheid museums' roles within South Africa's move toward reconciliation and social change. However, the examination of both the Red Location Museum and the Apartheid Museum reveals the extraordinary change that South African cultural institutions have undergone in addition to their potential to become institutions which facilitate active reconciliation as well as social and cultural growth.
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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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Contemporary left politics in South Africa: the case of the tri-partite alliance in the Eastern Cape

  • Authors: Hesjedal, Siv Helen
  • Date: 2010
  • Subjects: Politics, Practical -- South Africa Social classes -- South Africa -- History Political parties -- South Africa African National Congress South African Communist Party Cosatu Eastern Cape (South Africa) -- Politics and government Politics, Practical -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3295 , http://hdl.handle.net/10962/d1003083
  • Description: This thesis aims to make sense of Left politics in South Africa within the Tri-partite Alliance between the ANC, SACP and COSATU. The thesis focuses on developments in the Eastern Cape, between 2000 and 2008. The thesis describes the prevalent forms of Left politics in the Eastern Cape and the tendencies in the Alliance that organise this Left. The thesis also examines the historical, social and political conditions and that shape the form and content of Left politics in the province. Based on a survey of literature on what is considered the core manifestations of Left politics globally in the 20th Century Left politics is defined as the elements of the political spectrum that are concerned with the progressive resolution of involuntary disadvantage and with a goal of abolishing class society and capitalism. Although the Alliance as a whole should be seen to be on the Left on an international political spectrum, this thesis argues that the Left/Right dichotomy is useful for understanding the politics of the Alliance, as long as the second part of this definition is taken into consideration. The Alliance Left is understood as those leaders and activists within the Alliance that have the SACP and Cosatu as their operating base. It will be argued that this Left is, in its practice, largely concerned with what insiders refer to as politics of „influence‟, rather than with politics of „structural transformation‟. It is the ANC that is the leader of the Alliance and the party in government and thus it is on the terrain of ANC strategy, policy and positions that contestation in the Alliance plays itself out. Thus, for the Left, there is strength in the idea of the Alliance. However, there are significant theoretical and political weaknesses in the Left that undermine the possibility of making good use of various corporatist platforms to pursue the agenda of the Left in the Eastern Cape. There is also increased contestation within the Alliance Left itself about the continued usefulness of this strategy.
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Plant aphid interactions : effects of diuraphis noxia and rhopalosiphum padi on the structure and function of the transport systems of leaves of wheat and barley

  • Authors: Saheed, Sefiu Adekilekun
  • Date: 2008
  • Subjects: Russian wheat aphid Rhopalosiphum padi Aphids -- Host plants Wheat -- Diseases and pests
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4225 , http://hdl.handle.net/10962/d1003794
  • Description: The infestation of the cultivated grain crops by phloem feeding aphids has generated a great deal of interest over the years, due to the serious damage they cause to the crops and yield losses that result. The mechanism of the interaction between aphids and host plants remains largely unknown in spite of efforts to understand the basis of aphid feeding on grain crops. Greater efforts are required to explain the mechanism(s) of this interaction in order to achieve sustainable agriculture. This thesis focused on an investigation of the mechanism of feeding by the Russian wheat aphid, Diuraphis noxia Mordvilko (RWA) and the bird cherry-oat aphid, Rhopalosiphum padi L. (BCA) on barley and wheat cultivars. These two aphids co-occur naturally, but they inflict very different feeding effects on host plants. Structural and functional approaches were employed to investigate their feeding habits and these were then related to the observed differences in their host plants. Transmission electron microscopy (TEM) techniques were used to study the ultrastructural damage, while fluorescence microscopy techniques – using aniline blue fluorochrome (a specific stain for callose) and 5, 6-CFDA (a phloem-mobile fluorophore) – were employed to investigate the functional response to damage via wound callose formation and phloem transport capacity respectively. RT-PCR and quantitative real-time RT-PCR techniques were used to investigate the regulation of the genes involved in callose synthesis and degradation at the transcriptional level. Morphological observation of the damage caused by the aphids show that infestation by RWA results in extensive leaf chlorosis, necrosis and rolling, while infestation by BCA does not lead to any observable symptoms within the same period. Interestingly, the population study shows that BCA breeds faster than RWA within the two-week experimental period. The ultrastructural study of feeding damage caused by the two aphids on the vascular bundles of susceptible barley cv Clipper, shows a different patterns of damage. Probing the vascular bundles results in the puncturing of vascular parenchyma by both aphids, but severe damage occurs in sieve tubes-companion cell complex during sustained feeding by RWA. In contrast, less damage occurs when BCA feeds on the phloem. Drinking from the xylem by RWA results in deposition of a large quantity of electron-dense watery saliva, which apparently seals the xylem vessels completely, by blocking all the pit membrane fields between the xylem vessels and associated parenchyma cells. In contrast, drinking from xylem by BCA results in deposition of a dense, granular saliva into the xylem vessels only, which does not appear to totally occlude the pit membrane fields. This is the first known report in which ultrastructural evidence of aphids’ drinking in xylem is provided. The comparative effects of RWA feeding on a susceptible Betta and resistant Betta-Dn1 wheat cultivars showed that after two weeks, the Betta cultivar expressed damage symptoms such as chlorosis, necrosis and leaf roll, while few chlorotic patches and necrotic spots occur in resistant Betta-Dn1 cultivars. An ultrastructural investigation of the feeding damage caused to all leaf tissues revealed, for the first time, that RWA is capable of both intra- and inter-cellular probing within mesophyll cells. Probing in the mesophyll cells induces a more severe damage in susceptible Betta than in the resistant Betta-Dn1 counterpart. Similar differences in damage occurred during feeding in the thin-walled sieve tubes of the phloem, with the sieve tubes of the Betta showing more damage than that of the resistant Betta-Dn1. However, drinking from xylem resulted in the characteristic occlusion of metaxylem vessels by copious deposition of saliva by RWA in both Betta and Betta-Dn1 cultivars. In all cases of probing, feeding, and drinking by RWA in both cultivars, all probed cells with evidence of salivary material deposit and those cells adjacent to salivary material deposit, exhibit significant damage in susceptible Betta cultivar, whereas similar cells in Betta-Dn1 cultivars do not show as damage as severe. Investigation of the functional response of the plants to feeding by aphids through the deposition of wound-induced callose shows that formation and deposition of wound callose occurs in both longitudinal and cross veins within 24h of feeding by RWA. This deposition increases through short-term feeding (72h) and prolonged feeding (14d). This is in sharp contrast to the observations with BCA feeding,where little or no callose formation occurs within the same time frame. Callose formation and deposition occurs only when a higher population of BCA feeds on barley leaves. This is the first report of aphid-induced wound callose by BCA. In all cases of callose deposition, aphid stylet tracks were associated with callose and the deposition of callose appears to be a permanent feature, because wound callose remained in the leaf tissues even after 120h of the aphids’ removal. Wound callose signals (defence and anti-defence) are discovered to be transported in the phloem tissues and are dependent on the direction of assimilate flow. Examination of the possible regulation of wound callose genes at the transcriptional level shows that the two expressed glucan synthase gene sequences (GSL – genes involved in callose formation) analysed did not show any significant increase or regulation upon aphid infestation. Contrary to expectation, all three aphid-induced β-1, 3-glucanases (genes which are thought to be involved in callose degradation) showed higher expression in RWA-infested tissue than in BCA-infested tissue. The results of the feeding damage on the transport capacity of the phloem shows that BCA infestation does not lead to a significant reduction in the phloem transport capacity during short-term feeding (72h), while RWA-infested leaves showed considerable reduction in the transport capacity of the phloem within the same period. However, prolonged feeding (14d) by BCA induces a considerable reduction on the transport capacity of the phloem on the infested tissues. In contrast, a marked reduction in the transport capacity of the phloem occurs in RWA-infested leaves and in most cases, complete cessation of transport ensues. In conclusion, these data collectively suggest that RWA is a serious and most destructive phloem feeder in comparison to the BCA. RWA causes severe damage to all cellular tissues of the host plants, which result in apoplasmic and symplasmic isolation of xylem and phloem tissues, while BCA infestation does not result in such isolation within the same time and population levels. Resistance genes appear to function by conferring resistance to cell damage on the resistant cultivars during aphid feeding. Responses by plants to aphid infestation via wound callose deposition are again shown to be species-specific. A quick response results when RWA feeds, even at a very low population level, while a response occurs only at a higher infestation level by BCA, and this response was shown as not regulated at the transcriptional level. Differences in the damage to leaf tissues and wound callose deposition eventually lead to varying degrees of damage to the transport capacity of the phloem. These differences in the damage signatures are hereby suggested to be the cause of the diversity in the observed damage symptoms and the yield losses upon infestation by the two aphid species.
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A taxonomic revision of the genera of the subtribe Dracophilinae (Aizoaceae: Ruschioideae)

  • Authors: Mannheimer, Coleen Anne
  • Date: 2006
  • Subjects: Aizoaceae , Plants -- Classification , Cladistic analysis
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4247 , http://hdl.handle.net/10962/d1007461 , Aizoaceae , Plants -- Classification , Cladistic analysis
  • Description: Namibia, Juttadinteria and Dracophilus, the three genera belonging to the subtribe Dracophilinae Schwantes (Aizoaceae: Ruschioideae) were revised. Macro-morphology, leaf anatomy and micromorphology of leaf epidermides, pollen, tapetal orbicules and seed were studied in order to test taxon limits, to determine relationships between taxa, and to improve knowledge of their characteristics as well as the taxonomy of the subtribe. The investigation was based on herbarium specimens, field observations and cultivated, living plants. Phenetic cluster analyses were used to confirm species while intergeneric and interspecific relationships of the taxa so indicated were later tested by means of a phylogenetic analysis. The existence of the three genera was provisionally upheld by this study although phylogenetic analysis showed Namibia nested as a strongly supported monophyletic group within a poorly supported luttadinteria. Further work is needed to clarify whether Namibia should be sunk into Juttadinteria. The latest treatments of Juttadinteria and Dracophilus by Hartmann (2001) were supprted. However, in contrast to her latest treatment of Namibia, N. pomonae was sunk into N. cinerea and N. ponderosa was reinstated and typified. Juttadinteria was found to be a poorly resolved genus with many intergrading and overlapping characters, possible due to recent speciation. Possible subspecific groups within J. deserticola and J. simpsonii were indicated by the phenetic study but further work is needed before any formal infraspecific taxonomic rank can be assigned to them. Detailed descriptions of the nine elucidated species and the three genera as well as new keys for their identification are provided in order to facilitate further work in this group. Distribution maps are provided for the genera and species, and the subtribe. Variation of character states within the subtribe, distribution area, ecology and biology are discussed.
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An analysis of how the Senior Certificate examination constructs the language needs of English second language learners

  • Authors: Blunt, Sandra Viki
  • Date: 2006 , 2013-06-11
  • Subjects: Habermas, Jürgen Education, Secondary -- South Africa Examinations -- South Africa -- Evaluation English language -- Examinations -- South Africa English language -- Study and teaching -- South Africa -- Foreign speakers Language and education -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:1902 , http://hdl.handle.net/10962/d1006243
  • Description: The Senior Certificate (SC) examination, a focus of the research described in this thesis, has an important function in terms of the quality of the education system overall and also in terms of the contribution of education to the achievement of national goals. The SC examination functions i) as a measure of achievement at school ii) as an indicator of work readiness and iii) as an indicator of the potential to succeed in higher education. This thesis offers a critique of the SC examination in respect of its functions. The way in which learners' language related needs are constructed is crucial in discussing the SC examination's legitimacy since perceptions about the needs of learners are reflected in what is taught and assessed. Since the majority of candidates writing the SC exarnination do so using a language which is not their mother tongue, the research described in the thesis attempted to identify the way in which the English second language (ESL) SC examination papers construct learners' needs. Examination papers represent a particular domain of social practice and are constructed through discourse. In the context of the research described in this thesis, discourses are understood as sets of ideas which are shared by communities of people and which give rise to practices which then define and sustain those communities and, thus, the discourses themselves. Discourse is language insofar as it converges with power and positions people in the interests of power. The ideological nature of discourse necessitates a critical orientation to research which interrogates, challenges and critiques the status quo. To identify the discourses constructing ESL learners' needs I conducted a critical discourse analysis on a representative sarnple of ESL SC exarnination papers and also interviewed six ESL examiners to corroborate the findings of the analysis. This then allowed me to identify several dominant discourses constructing ESL learners' needs: meaning-related, literature-related and process-related. The first meaning-related discourse, 'Received Tradition' discourse, focuses on the rules of grammar and spelling. Rather than approaching language as a resource to enable learners to understand the ideas to which they are exposed, learners are being taught discrete 'skills' to equip them for higher education study and the workplace. It is argued that school-based language literacy practices are not generalizable to the workplace and to higher education. Another aspect of 'Received Tradition' discourse holds that the study of English literature is a medium for understanding life and that there is moral value in teaching English literature. Learners are therefore constructed as lacking these values and their needs as having to acquire them. 'Received Tradition' discourse also overlaps with a second meaning-related discourse, 'Autonomous Text' discourse, which holds that the text's meaning is explicit and that if the learners can manipulate the rules of English grammar, 'have' vocabulary and can spell, they can retrieve meanings from texts they encounter in a wide range of contexts and construct texts for themselves. It is argued that a lack of awareness that meaning is constructed through recourse to other contexts, texts and the learner's experience is disadvantaging ESL candidates. 'Language as an Instrument of Communication' discourse, the last meaning-related discourse identified, sees language as the vehicle used to convey ideas, thoughts, information and beliefs, which are viewed as having been constructed independently of language. It is assumed that the answers, which, according to 'Autonomous Text' discourse, are in the text, can be conveyed if the tools of language are used correctly. The first literature-related discourse identified is 'Literature Study Develops Language Proficiency'. It is argued this is a misperception since language is learned as part of situated practice and instruction must thus be embedded in meaningful communicative contexts involving situated practice. The second literature-related discourse identified, 'Literature Study is a Medium for Understanding Life', is connected to the 'Received Tradition' discourse referred to above which holds that there is moral value in teaching English literature. This research identifies the ideological implications of these discourses, arguing that values are culture-specific and learners from diverse socio-cultural backgrounds experience life differently from the way it is depicted in English literature. Process-related discourses, which are part of the processes of teaching and assessment, concern the inadequacy of the ESL learner and of the markers and therefore dictate what can and cannot be expected of ESL learners in the SC examination. The research showed how all of the above discourses work through the SC curriculum to impose the values and beliefs of particular dominant groups on the ESL learner. Because of the robust and invidious nature of discourses this is a cause for concern. Although it is difficult to set a school leaving examination which serves both workplace and academic functions, there is a need to move beyond traditional, hegemonic approaches to understanding language learning. This thesis offers an analysis which can be used to inform practice.
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Graphicacy and the third dimension: an investigation into the problem of poor performance in relief mapwork in South African secondary schools

  • Authors: Burton, Michael St. John Whitehead
  • Date: 1986
  • Subjects: Graphicacy , Maps , Map reading , Visualisation , Geography , Secondary education , South Africa , Pupils , Learners , Teachers
  • Language: English
  • Type: text , Thesis , Masters , MEd
  • Identifier: vital:1358 , http://hdl.handle.net/10962/d1001424
  • Description: Three-dimensional graphicacy is the part of map work that appears to be the most problematIcal. Bartz (1970) says that thinking and visualising in three-dimensional space is difficult enough, but trying to derive notions in three-dimensions, when you have only seen them as they are represented in distorted two-dimensional fashion, is even more difficult. Yet pupils of geography are required to learn such three-dimensional concepts from the two-dimensional distorted map presentations. The geography teacher has an important educational role to play in promoting graphicacy and Balchin (1965), who coined the term, felt that it should be an essential underpinning of an integrated education. The problem is that children perform badly, teachers are not successfully imparting three-dimensional graphicacy skills and as Board and Taylor (1977) indicate, for some time now it has been fashionable to dismiss maps as being irrelevant or useless in geographical research. This thesis attempts to analyse this reported malady, the problems are exposed and solutions offered. Investigation of the literature, with the aim of clarifying the problems involved, follows four leads. These are the part played by the map as a mode of communication, the physical processes involved in mapwork revealed by work in the realm of neurophysiology, the process of visualisation in the field of perception and psychology, and finally the stage of conceptual development of the mapworker. The state of affairs in South Africa is disclosed by an analysis of teacher-directed literature, of examination syllabuses, of text-book treatment of three-dimensional mapwork in South Africa and overseas, of past examination questions, and finally of teachers' views. Experimental exercises have been executed in an attempt to link the key findings of published research to the local scene. Conclusions are then drawn, and recommendations made for improving three-dimensional graphicacy in South African secondary schools.
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Satan and Lucifer: a comparison of their metamorphoses from Angel to Devil in Milton's Paradise lost and Vondel's Lucifer and Adam in Ballingschap

  • Authors: Paterson, Lynette
  • Date: 1979
  • Subjects: Milton, John, 1608-1674 Vondel, Joost van den, 1587-1679
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2184 , http://hdl.handle.net/10962/d1001837
  • Description: The aim of this thesis is to compare the poetic delineation of the character of Satan in Paradise Lost with that of Lucifer in Lucifer and Adam in Ballingschap, and to consider the influence of the genre in each case , not in order to prove similarities or differences , but rather to allow the characters to illuminate each other. Both Satan and Lucifer develop progressively from angel to devil in the course of the poem or play. However, this process is more than just a physical metamorphosis, or even a moral degeneration. It is in each case a process of identity change, intensely and consciously experienced by the character. The fall is a movement from God to Self. The unfallen creature's integrity consists in his submergence in the Being and Will of God; for the fallen creature integrity means a separate, independent self-hood. In rebelling against their role and duty as Archangel, Satan and Lucifer rebel against submergence in the Being of God and thus against their very nature and the order of things. Consequently they experience personal and psychological disintegration. From this condition of imbalance and uncertainty they both develop to a new state of personal reintegration and unequivocal identity, now as Arch-fiend. In neither case is the process instant or entirely concurrent with the physical fall into Hell. Rather, it is protracted, hence the division of this thesis into sections that focus on the different stages in the development: Archangel, Arch-rebel and Arch- fiend (introduction, p. ii-iii).
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The chemistry of naturally occurring long chain unsaturated compounds

  • Authors: Silk, M H
  • Date: 1954
  • Subjects: Compounds, Unsaturated
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4518 , http://hdl.handle.net/10962/d1014332
  • Description: [From Introduction, p. 3] Raw marine oils are subject to considerable variation in composition with season and are moreover very unbalanced oils for direct use in the paint industry. Further refining is undertaken chiefly by Messrs Marine Oil Refiners of Africa Ltd., whose factory is situated at Simonstown. In their plant marine oils and others are treated by the Solexol process involving counter current extraction of the oil with liquid propane in a tower over which a temperature gradient is maintained. The process achieves the removal of a large proportion of the relatively saturated glycerides, the natural antitioxidants, and the relatively highly unsaturated components, all of which are detrimental to the eventual formation of good paint films. The segregated marine oil from the Solexol process is then bodied or polymerised at high temperatures to yield a "drying oil" which is used as a substitute for bodied linseed oil in paints. The chemical reactions taking place during the polymerisation and drying of these oils are of an exemely complex nature, and for their understanding it is necessary to have an accurate knowledge of the chemical nature of the component fatty acids in the natural glycerides ... The term "marine oils" in this work should be understood to mean marine fish body oils, marine mammal oils being excluded from consideration.
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