The impact of HAART on sexuality and medicine taking behaviours among people living with HIV/AIDS in Grahamstown
- Authors: Chizanga, Tongai Aldridge
- Date: 2010
- Subjects: AIDS (Disease) -- Treatment -- South Africa -- Grahamstown HIV infections -- Treatment -- South Africa -- Grahamstown Antiretroviral agents -- South Africa -- Grahamstown Patient compliance -- South Africa -- Grahamstown AIDS (Disease) -- Social aspects -- South Africa -- Grahamstown HIV infections -- Social aspects -- South Africa -- Grahamstown AIDS (Disease) -- Patients -- South Africa -- Grahamstown -- Sexual behavior HIV-positive persons -- South Africa -- Grahamstown -- Sexual behavior Patient education -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3750 , http://hdl.handle.net/10962/d1003228
- Description: Introduction: Adherence to Highly Active Antiretroviral Therapy (HAART) is critical for optimal therapeutic outcomes. A possible factor in adherence is the impact of HAART on sexual functioning. Methods: A mixed methods approach was used. A cohort of 14 people living with HIV/AIDS (PLWHA) in Grahamstown was identified. Two semi-structured interviews and two structured questionnaires were administered. In-depth interviews were conducted with two HIV counsellors in so as to obtain a different perspective on the topics. The theoretical framework used three health behaviour models: the Health Belief Model, Leventhal‘s Common-Sense Model of self regulation and the Transtheoretical model. Results: The participants were between 27 and 49 years old and had been on HAART for between 9 months and 10 years. Six participants were support staff members from Rhodes University and eight from the Raphael Centre – a local NGO which assists PLWHA.In most of the participants HAART was associated with increased libido and improved sexual functioning (sexual activity and sexual enjoyment). The use of alcohol increased risky sexual behaviour. Issues of adherence were seemingly not directly affected by the effects of HAART on sexuality. PLWHA, especially women, face challenges related to their sexuality, some of which are not directly related to their illness and treatment. The fear of transmitting drug resistant HIV or getting re-infected, stigma, disclosure issues,difficulties negotiating for safe sex among women, HAART-related lipodystrophic changes that affect one‘s sense of self and unmet reproductive needs are some of the problems that were reported. The men‘s dislike for condoms was overt and blatant. Discussion: Being diagnosed with HIV and reaching a point where treatment is requiredare life-changing events. Making decisions about one‘s life (including adherence to HAART, alcohol use and knowingly partaking in risky sexual encounters) become all the more significant in the context of AIDS. Intentional non-adherence is informed by the individual‘s assessment of the costs and benefits of taking treatment. Cultural influences,gendered power relations and misconceptions strongly influence sexual behaviours. Conclusion: The general lack of attention among health care providers concerning issues related to PLWHA‘s sexuality and reproductive issues needs to be addressed. Insights fromthe theoretical models should be integrated with empirical findings in designing adherence interventions.
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- Date Issued: 2010
The influence of Acacia Mearnsii invasion on soil properties in the Kouga Mountains, Eastern Cape, South Africa
- Authors: Van der Waal, Benjamin Wentsel
- Date: 2010
- Subjects: Acacia mearnsii -- South Africa , Wattles (Plants) -- South Africa , Soil erosion -- South Africa -- Eastern Cape , Conservation of natural resources -- South Africa , Biological invasions -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Biogeography -- South Africa -- Eastern Cape , Soil management -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape , Soils -- Sodium content -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4839 , http://hdl.handle.net/10962/d1005515 , Acacia mearnsii -- South Africa , Wattles (Plants) -- South Africa , Soil erosion -- South Africa -- Eastern Cape , Conservation of natural resources -- South Africa , Biological invasions -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Biogeography -- South Africa -- Eastern Cape , Soil management -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape , Soils -- Sodium content -- South Africa -- Eastern Cape
- Description: The invasion of Acacia mearnsii in the Kouga catchment, Eastern Cape, South Africa, has various negative impacts on the ecosystem. These impacts include: reduced species richness, increased water use, increased nutrients and increased N cycling rates. The native shrubby fynbos vegetation has adapted to the acidic nutrient poor soils and Mediterranean climate of the Kouga Mountains. Fynbos, however, is currently being out competed by the much taller Acacia mearnsii trees, due to their competitive nature and ability to fix nitrogen, thereby enriching the soil. The invaded sections of the valley bottoms and lower hill slopes are characterised by an almost complete monoculture of Acacia mearnsii, with very few fynbos species still present. The Department of Water and Environmental Affairs sponsored Working for Water programme started clearing Acacia mearnsii in 1996 in the Kouga Mountains. Cleared sites have remained bare for long periods, indicating that soil properties are not favourable for indigenous propagule re-establishment. The aim of this research was to assess how A. mearnsii invasion and clearing affect fynbos recovery through its impact on soils. This was done by characterising vegetation and soil properties on fynbos, infested and cleared slopes. Vegetation cover for various growth forms was determined and a species list was compiled for each plot. The slope angle, surface hardness, litter cover, bare ground cover and soil depth were measured in the field, whereas water repellency, particle size and the chemical composition were measured in the laboratory. Furthermore, the plant establishment capacity of soils from fynbos, infested and cleared slopes was calculated. This was done by germinating fynbos seeds and growing fynbos plants in soils from the various slopes. The effect that invasion and clearing has on soil erosion was quantified using erosion plots on fynbos, infested and cleared slopes. The invasion and clearing of Acacia mearnsii led to an increase in soil nutrients, especially nitrogen, phosphorus, potassium, carbon and manganese. Furthermore, soils became more acidic, with increased water repellency and reduced surface hardness. The vegetation changed to a tree-dominated structure, replacing the native species. Native plant germination was relatively unaffected by invasion and clearing, with an increase in germination just after clearing. Plant growth of a native grass, Themeda triandra, and herb, Helichrysum umbraculigerum, has increased on soils from cleared slopes. This study showed that soil movement increased on slopes which are invaded and cleared of Acacia mearnsii, with erosion rates doubling on invaded slopes
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- Date Issued: 2010
The influence of strategic leadership in an organization: a case study : Ellerine Holdings Limited
- Authors: Mathura, Vikash
- Date: 2010
- Subjects: Strategic planning -- South Africa Case studies Leadership -- South Africa Case studies Corporate culture -- South Africa Case studies Organizational behavior -- South Africa Case studies Organizational change -- South Africa Case studies Furniture industry and trade -- South Africa Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:750 , http://hdl.handle.net/10962/d1003871
- Description: A review of the academic literature related to “strategic leadership” reveals that the performance of an organization will indeed be influenced by the application of this phenomenon. This thesis confines its research to a case study on Ellerine Holdings Limited, a multi-billion rand enterprise that trades in the competitive Southern African furniture retail industry. Following the 2007 acquisition of Ellerine Holdings Limited (EHL) by African Bank Investments Limited (ABIL), a new Chief Executive Officer (CEO) was appointed to develop and to lead the strategic changes that were envisioned for EHL. The research examines how the performance of EHL has been influenced since the appointment of Toni Fourie as the new CEO in February 2008. Boasting a reputation borne from his previous successes in organizational transformation, Fourie was ABIL’s first-choice leader for this challenge. Fourie displays qualities, attributes, behaviours and traits that are characterized by the phenomenon of “strategic leadership”. He has been the focus of media attention for the aggressive strategic changes that he has introduced within the organization. A quantitative analysis of EHL’s financial performance (between 2007 and 2009) indicated that there was a constant decline in the organization’s PBT (Profit Before Taxation) during the period observed. However, the research determined that turbulent conditions in the macro-economic environment (such as the global economic recession in 2008 and 2009) complemented by mitigating micro-economic factors, would have adversely skewed the conclusions in this document if the research was limited to quantitative analysis alone. Hence, the researcher explored a qualitative research framework by collecting and assimilating data from available documentation, and from formal interviews that were conducted with research participants representing the organization’s new leadership. These participants included the new CEO, Fourie, and the new Director of Strategy, Dr. Louis Carstens. Information was also obtained from informal discussions that were conducted with other senior executives, and with an ex general manager of one of EHL’s business units, who was based in the Eastern Cape region at the time. An examination of all of this data concluded that although Ellerine Holdings Limited was not achieving all of its financialperformance objectives, there was general consensus that the CEO’s strategic choices would yield the desired financial results from the mediumterm (namely, year-03 of his tenure) onwards. The CEO’s optimism and conviction that his strategic interventions will address long-term financial sustainability is shared by both EHL’s internal and external stakeholders. It emerged that EHL’s stakeholders were satisfied with the accelerated progress reflected in the organization’s non-financial performance indices. These indicators included the sowing of a new organizational culture; improved cost-base efficiencies; labour productivity; customer satisfaction; employee empowerment; innovation and creative thinking; collaborative and participative engagement; structural rationalization, and the introduction of new processes and procedures. The research from the EHL case study concluded that the phenomenon of strategic leadership can have a positive influence on various qualitative indicators within an organization. The research also determined that despite unforeseen conditions in both the macro and micro economic environments, an effective strategic leadership will remain committed to its vision, and resilient to its critics and competitors. This research further concludes that successful organizational transformation (within a macro enterprise) is ostensibly dependent on the interventions of a strategic leader who displays a specialist set of skills and behaviours. These strategic leaders have the ability to successfully shift the cognitive paradigms of their employees, thereby creating an enabling environment for the implementation of their strategic choices.
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- Date Issued: 2010
The integration of natural resource management into the curriculum of rural under-resourced schools : a Bernsteinian analysis
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2010
- Subjects: Conservation of natural resources -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa -- Eastern Cape Bernstein, Basil B Nature conservation -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4762 , http://hdl.handle.net/10962/d1007157
- Description: This study was motivated by the need to improve curriculum relevance in poor rural schools through contextualised teaching and learning based on the management of local natural resources. It involved four schools which are located in the Ngqunshwa Local Municipality of the Eastern Cape Province of South Africa. The study's aim was to provide insight into and better understanding of the curriculum implementation process regarding natural resource management (NRM) education in a poor rural education context. This was done by analysing the extent of NRM integration in pedagogic texts, activities and practices in the different fields which constitute the structure of the pedagogic system in this education sector. The study adopted an interpretivist approach to the analysis, which was based on indicators of the extent of NRM integration, and was informed by Bernstein's concepts of classification and curriculum recontextualisation, and his model of the structure of the pedagogic system. The items which were analysed included national and provincial Grade 10 Life Sciences curriculum documents, Grade 10 Life Sciences textbooks, in-service training workshops for Life Sciences teachers, and various school documents, activities and practices. The analysis also involved interviews with educators, and classroom observations of Grade 10 Life Sciences lessons. The results revealed a very high overall level of NRM integration in the Grade 10 Life Sciences curriculum documents produced at national and provincial levels. The overall level of NRM integration was also found to be very high in the Grade 10 Life Science textbooks that were analysed, but very low in the in-service teacher training workshops, and in the schools' documents, activities and practices, especially in the Grade 10 Life Sciences lessons, and in schools' end-of-year Grade 10 Life Sciences examination papers. The study makes a number of recommendations towards effective integration of NRM into the curriculum of Eastern Cape's rural poor schools which include more specific and explicit reference to NRM in the official Grade 10 Life Sciences curriculum documents, the provision of environmental education courses to district education staff and Grade 10 Life Sciences teachers, the training of teachers in the classroom use of textbooks and other educational materials, and regular monitoring of teachers' work. The study also exposes important knowledge gaps which need urgent research attention in order to enhance NRM education in the poor rural schools of the Eastern Cape. These include analysing power and control relationships between the various agencies and agents that are involved with curriculum implementation in this education sector, and conducting investigation into the creation of specialist NRM knowledge and into the quality of NRM knowledge that is transmitted as pedagogic discourse in schools. This study contributes to the fields of rural education and environmental education in South Africa, and to the growing interest in the study of curriculum from a sociology of education perspective in the context of the country’s post-apartheid curriculum reforms.
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- Date Issued: 2010
The isolation of muscle activity and ground reaction force patterns associated with postural control in four load manipulation tasks
- Authors: Pettengell, Clare Louise
- Date: 2010
- Subjects: Physical fitness , Exercise , Materials handling , Manual work , Lifting and carrying
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5125 , http://hdl.handle.net/10962/d1005203 , Physical fitness , Exercise , Materials handling , Manual work , Lifting and carrying
- Description: Although much effort has been placed into the reduction of risks associated with manual materials handling, risk of musculoskeletal disorder development remains high. This may be due to the additional muscle activity necessary for the maintenance of postural equilibrium during work tasks. This research proposes that postural control and subsequent additional muscle activity is influenced by the magnitude of the external load and the degree of body movement. The objective of this research was to identify whether performing tasks with increased external load and with a greater degree of trunk motion places additional strain on the musculoskeletal system in excess of that imposed by task demands. Twenty-four male and twenty-four female subjects performed four load manipulation tasks under three loading conditions (0.8kg, 1.6kg, and 4kg). Each task comprised of a static and dynamic condition. For the static condition, subjects maintained a stipulated posture for ten seconds. The dynamic condition required subjects to move and replace a box once every three seconds, such that a complete lift and lower cycle was performed in six seconds. Throughout task completion, muscle activity of six pairs of trunk muscles were analysed using surface electromyography. This was accompanied by data regarding ground reaction forces obtained through the use of a force platform. After the completion of each condition subjects were required to identify and rate body discomfort. Differential analysis was used to isolate the muscle activity and ground reaction forces attributed to increased external load and increased trunk movement. It was found that the heaviest loading conditions (4kg) resulted in significantly greater (p<0.05) muscle activation in the majority of muscles during all tasks investigated. The trend of muscle activity attributed to load was similar in all significantly altered muscles and activation was greatest in the heaviest loading condition. A degree of movement efficiency occurred in some muscles when manipulating loads of 0.8kg and 1.6kg. At greater loads, this did not occur suggesting that heavier loading conditions result in additional strain on the body in excess of that imposed by task demands. In manipulated data, trend of vertical ground reaction forces increased with increased load in all tasks. Sagittal movement of the centre of pressure attributed to load was significantly affected in manipulated data in the second movement phase of the “hip shoulder” task and the second movement phase of the “hip twist” task. The “hip reach” task was most affected by increased load magnitude as muscle activity attributed to load was significantly different (p<0.05) under increased loading conditions in both movement phases in all muscles. Further, a significant interactional effect (p<0.05) between condition and data point was found in all muscles with the exception of the right and left lumbar erector spinae during the second movement phase of the “hip reach” task. Muscle activity associated with increased trunk motion resulted in additional strain on the trunk muscles in the “hip shoulder” and “hip reach” tasks as muscle activity associated with the static component of each of the above tasks was greater than that of the dynamic tasks. Trend of ground reaction forces attributed to increased trunk motion generally increased under increased loading conditions. Additionally, a significant interactional effect (p<0.05) between load and muscle activity pattern was found in all muscles during all tasks, with the exception of the right rectus abdominis in the first movement phase of the “hip shoulder’ task, the left rectus abdominis in the second movement phase of the “hip knee” task and the right latissimus dorsi during the first movement phase of the “hip twist” task. This was accompanied by a significant interactional effect (p<0.05) between load and sagittal centre of pressure movement attributed to load, in both movement phases of all tasks investigated. From this research it can be proposed that guidelines may underestimate risk and subsequently under predict the strain in tasks performed with greater external loads as well as tasks which require a greater degree of trunk motion. Therefore, this study illustrates the importance of the consideration of the muscle activity necessary to maintain postural equilibrium in overall load analyses.
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- Date Issued: 2010
The migration of the term "civil war" : a social constructivist explanation
- Authors: Bailie, Lawrence Craig
- Date: 2010
- Subjects: Civil Wars United States -- History -- Civil War, 1861-1865 Iraq -- History -- Civil War, 1991
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2845 , http://hdl.handle.net/10962/d1006022 , DOI http://doi.org/10.21504/10962/d1006022
- Description: Although the occurrence of wars between states has been in decline, the same cannot be said of conflict within states – especially when considering the innumerable ‘Civil Wars’ said to have occurred since the end of the Cold War. In this context the use of the word ‘innumerable’ is qualified more by the variance in how ‘Civil War’ is understood as a concept (leading to different claims as to how many conflicts of this kind may have occurred over a period of time) and less by their large number. Claims regarding the occurrence of ‘Civil War’ suggest this type of conflict to be the dominant form at least since the end of World War Two. This prevalence in the face of a decline in inter-state warfare has afforded greater interest to ‘Civil War’ as a topic of inquiry. The understanding that ‘Civil Wars’ have with time increased in their occurrence and changed in their nature comes under investigation in this thesis and is seen as problematic in that the means by which a phenomenon is measured (i.e. through its nature) must be fixed so as to measure the frequency of that phenomenon. Using Social Constructivism as a theoretical lens of inquiry, sense is made of this understanding and, furthermore, the true meaning behind the claim that ‘Civil War’ has changed is revealed. The empirical evidence that accompanies this theoretical work exists in the American Civil War of 1861–1865 and the debate over the conflict in Iraq following the U.S. invasion in 2003. This debate is used as a means by which to bring the contestation over the notion of ‘Civil War’ to the fore, while a comparison of this conflict with the quintessential American Civil War reveals the migration of the term.
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- Date Issued: 2010
The neo-diaspora : examining the subcultural codes of hip-hop and contemporary urban trends in the work of Kudzanai Chiurai and Robin Rhode
- Authors: Stirling, Scott
- Date: 2010
- Subjects: Chiurai, Kudzanai, 1981- Rhode, Robin Hip-hop African diaspora Rap (Music) Art, Modern -- 21st century Art, South African -- 21st century Hip-hop dance -- South Africa Hip-hop dance -- United states Hip-hop -- Influence -- South Africa Hip-hop -- Influence -- United states
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2423 , http://hdl.handle.net/10962/d1002219
- Description: This thesis is structured around an exploration of the global phenomenon hip-hop. It considers how its far-reaching effects, as a cultural export from the United States,have influenced cultural production in South Africa. The investigation focuses specifically on the work of two visual artists: Zimbabwean born, Johannesburg-based Kudzanai Chiurai, and Cape Town born, Berlin-based Robin Rhode. The introduction familiarises the reader with the two artists and briefly outlines their histories and methods, as well as giving a short history of the development of hip-hop as a subculture from its beginnings in 1970s New York. The first chapter follows this brief introduction to outline some of the parallels, especially concerning race relations, between 1970s America and post-apartheid contemporary South Africa. This comparison aims to highlight similarities that gave rise to the hip-hop phenomenon and which also place South Africa in a prime position to welcome such influences. The second half of the chapter explores how migration theory and issues of diaspora have not only influenced the development of hip-hop, but have also become points of focus for both artists, who are in fact disporans themselves. The second chapter explores ‘ground level’ concerns of everyday life in the city. Issues of crime,gangsterism, politics and activism are characterised as focal elements of Chiurai’s and Rhode’s artwork and also of hip-hop musical content. Inner city contexts in different parts of the globe are compared through a discussion of the art and music that come out of them. This comparison of the philosophical and conceptual content of the art and music is extended, in Chapter three, into a comparison of methods of production, considering how these influence various readings of the artistic output, whether musical or visual. Ideas of authenticity are discussed and finally the focus shifts to explore how both the conceptual and practical concerns of musicians and artists are being shaped by an increasingly ‘globalized’ world. The conclusion explores the challenges that globalization poses to cultural practitioners and seeks to highlight some of the artists’ methods as examples with which to facilitate the growth of a more inclusive global aesthetic.
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- Date Issued: 2010
The phytogeography of the Sneeuberg, Nuweveldberge and Roggeveldberge (Great Escarpment): assessing migration routes and endemism
- Authors: Clark, Vincent Ralph
- Date: 2010
- Subjects: Phytogeography -- South Africa Endemic plants -- South Africa Plants -- Migration -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4187 , http://hdl.handle.net/10962/d1003756
- Description: The Great Escarpment forms a semi-continuous mountain system 5 000 km long, stretching from Angola in the north-west, south through Namibia, and into western, southern and eastern South Africa, including Lesotho and Swaziland. It is composed of a wide variety of geological suites but is unified in representing the edge of the African plateau and the passive Gondwanan continental margin. The Great Escarpment falls into all major climatic zones on the subcontinent, is a repository of palaeo- and neo-endemics, hosts more than half of southern Africa‟s centres of plant endemism, and has a rich suite of endemic fauna. In addition, the Great Escarpment is believed to be both a refugium and corridor for biological diversity. Despite the biological richness of the Great Escarpment, research to date has been fragmented and many sections of the Great Escarpment have not been studied. The aim of this study is to contribute to research on the Great Escarpment by undertaking a detailed floristic study of the southern Great Escarpment (the Sneeuberg, Nuweveldberge and Roggeveldberge). Together these mountains comprise approximately 1 000 km (one fifth) of the Great Escarpment, and occupy a transition zone between the summer rainfall zone in the east and the winter rainfall zone in the west. They are also the sections of Great Escarpment most closely situated to the Cape Floristic Region (CFR) and would thus be involved in hypothesised migration routes for lineages that also occur further north through the Drakensberg Alpine Centre (DAC) to the East African mountain chain. Detailed fieldwork of the southern Great Escarpment was undertaken over a period of four years in all seasons. Approximately 8 000 specimens were collected. Particular emphasis was placed on areas that may represent refugia, i.e. the highest plateaux and peaks, mesic areas and cliff-lines. An overview of each mountain range, together with their endemic plant species and phytogeography, is provided. Approximately ten new species have been discovered during this study, two of which have been described to date. Numerous endemics only known from their types have also been rediscovered. The Sneeuberg is defined as a new centre of plant endemism on the Great Escarpment (endemism of 2.3%), and the role of the Boschberg and Groot-Bruintjieshoogde (part of the Sneeuberg) as a nexus for floristic migration routes is discussed. The Nuweveldberge is shown to have low endemism despite a floristic tally similar to the Sneeuberg, while the Roggeveldberge are confirmed to be the most endemic-rich section of the southern Great Escarpment. The field data collected was augmented by available data in taxonomic revisions, and floras for the Sneeuberg, Nuweveldberge and Roggeveldberge were compiled. In order to floristically compare the southern Great Escarpment with other sections of the Great Escarpment and the CFR, a database of some 12 000 taxa was created using available floristic data for the CFR, DAC and Great WinterbergAmatolas, together with the data collated for the Sneeuberg, Nuweveldberge and Roggeveldberge. These data were analysed using phenetic methods and Parsimony Analysis of Endemicity (PAE). The results indicate stronger linkages in the east, particularly between the Sneeuberg and Nuweveldberge, and between the Sneeuberg and the Great WinterbergAmatolas. The relationship of the Roggeveldberge with the rest of the southern Great Escarpment remains ambiguous. In order to refine notions of connectivity and migration routes, 19 well-sampled phylogenies were assessed for sister-taxon disjunctions to explore CFRGreat Escarpment connections. Palaeo-connectivity between the CFR and southern Great Escarpment is most strongly supported for the south-eastern (SE) connection, and less so for the north-western (NW) and Matjiesfontein connections. There is support for the current (or recent) use of these three connections from numerous species that occur on both sides of the connections. Results of these analyses indicate that the southern Great Escarpment is a palaeo-corridor, the functioning of which has been broken by the aridification of the Nuweveldberge since the Last Glacial Maximum (LGM). Floristic connectivity is strongest in the east, from the Nuweveldberge to the DAC, and is less so in the west between the Nuweveldberge and the Roggeveldberge a finding attributed to the transition from a reliable winter rainfall regime on the Roggeveldberge to an unpredictable moisture regime on the Nuweveldberge. The mountains of the southern Great Escarpment are thus a series of refugia from a previous moister, cooler climate and are a corridor between the eastern and western components of the Great Escarpment. The SE connection is the primary link between the CFR and the eastern Great Escarpment Afromontane region in southern Africa. The implications of this research are that accurate conservation assessments and Red Data listings for many of the previously poorly-known endemics can now be made, and appropriate conservation measures implemented. Climate change remains the primary threat to these endemics and montane taxa in general, while degradation of wetlands is the primary threat to the water catchment service provided by the southern Great Escarpment. Future detailed research on the Great WinterbergAmatolas and Stormberg and a comprehensive flora of the HantamRoggeveldberge will further enhance our understanding of the floristics of the southern Great Escarpment, and provide the necessary data for comprehensive GIS-based models of proposed climate change scenarios for local, regional and national conservation planning.
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- Date Issued: 2010
The political economy of development aid: an investigation of three donor-funded HIV/AIDS programmes broadcast by Malawi television from 2004 to 2007
- Authors: Mulonya, Rodrick K A R
- Date: 2010
- Subjects: Economic assistance -- Malawi -- Management , Public service television programs -- Malawi , AIDS (Disease) and mass media -- Malawi , HIV infections -- Information services -- Malawi , Communication in public health -- Malawi , Economic assistance -- Social aspects -- Malawi , Malawi -- Social conditions , Mass media -- Social aspects -- Malawi , Mass media criticism -- Malawi
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3471 , http://hdl.handle.net/10962/d1002926
- Description: Development aid in most of the developing countries can sometimes compromise the principles of public service broadcasting (PSB). This may be true when reflected against the tension between donor financed programmes in Malawi and the mandate of Television Malawi (TVM). Although the donor intentions are noble, the strings attached to the funding are sometimes retrogressive to the role of PSBs. A case in point is how donors dictate terms on the HIV/Aids communication strategies at TVM. Producers receive money from donors with strings attached on how the money should be used and accounted for. If producers deviate they are sanctioned through withholding funding, shifting schedules and reducing the funding frequency. The donors also dictate who to interview on what subject, how to conduct capacity building. Some scholars have researched much on the impact of commercialisation of the media. This study is a departure from these traditional interferences; it interrogates the interest of philanthropy tendencies by international donors in the three chosen HIV/Aids programmes broadcast by TVM. The study investigates the extent of pressure exerted by donors on the producers of HIV/Aids programmes in Malawi. Thus, the study seeks to illicit specifics in the power relationship between the donor and the producer hence the study employs the political economy of development aid as applied to the public service broadcasting and communication for development. The study employed qualitative research methods and techniques (in-depth interviews, case study and document analysis). The study reveals how donor ideologies dominate the Aids messages-content output of the texts constructed. The study argues that cultural alienation of the Malawian audiences retards efforts of donors in combating HIV infection rate.
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- Date Issued: 2010
The presentation of the orphan child in eighteenth and early nineteenth century English literature in a selection of William Blake's 'Songs of innocence and experience', and in Charlotte Brontë's 'Jane Eyre', and Emily Brontë's 'Wuthering Heights'
- Authors: Singh, Jyoti
- Date: 2010 , 2013-07-18
- Subjects: Blake, William, 1757-1827 -- Songs of innocence and of experience -- Characters -- Orphans Blake, William, 1757-1827 -- Criticism and interpretation Brontë, Charlotte, 1816-1855 -- Jane Eyre -- Characters -- Orphans Brontë, Charlotte, 1816-1855 -- Criticism and interpretation Brontë, Emily, 1818-1848 -- Wuthering Heights -- Characters -- Orphans Brontë, Emily, 1818-1848 -- Criticism and interpretation Orphans in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2267 , http://hdl.handle.net/10962/d1005628
- Description: This thesis is a study of the presentation of the orphan child in eighteenth and early nineteenth century English literature, and focuses on William Blake's Songs of Innocence and Experience, Charlotte Bronte's Jane Eyre, and Emily Bronte's Wuthering Heights. It is concerned with assessing the extent to which the orphan children in each of the works are liberated from familial and social constraints and structures and to what end. Chapter One examines the major thematic concern of the extent to which the motif of the orphan child represents a wronged innocent, and whether this symbol can also, or alternatively, be presented as a revolutionary force that challenges society's status quo in Blake's Songs of Innocence and Experience. Chapter Two considers the significance of the child "lost" and "found", which forms the explicit subject of six of Blake's Songs of Innocence and Experience and explores the treatment of these conditions, and their differences and consequences for the children concerned. Chapter Three focuses on Charlotte Bronte's depiction of the orphan in Jane Eyre, which presents two models of the orphan child: the protagonist Jane, and Helen Burns. The chapter examines these two models and their responses to orphan-hood in a hostile world where orphans are mistreated by family and society alike. Chapter Four determines whether the orphan constitutes a subversive threat to the family in Emily Bronte's Wuthering Heights and also explores the notion that, although orphan-hood often entails liberation from adult guardians, it also comprises vulnerability and exposure. The thesis concludes by considering the extent to which orphan-hood can involve a form of liberation from the confines of social structures, and what this liberation constitutes for each of the three authors.
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- Date Issued: 2010
The relationship between bank concentration and the interest rate pass through in selected African countries
- Authors: Mangwengwende, Tadiwanashe Mukudzeyi
- Date: 2010
- Subjects: Interest rates -- Effect of inflation on -- Africa , Monetary policy -- Africa , Prime rate , Prime rate -- Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:942 , http://hdl.handle.net/10962/d1002675
- Description: Given the importance of monetary policy in the operation of a successful modern economy and the use of official interest rates as tools in its implementation, this study investigates the implications of changing bank concentration on the operation of the Interest Rate Pass Through (IRPT) of official rates to bank lending and deposit rates. This is an issue made more poignant by growing mergers, acquisitions and bank consolidation exercises around the world that have brought interest to their implications for economic performance. However, with contention high in the industrial organisation theory on the likely relationship between bank concentration and the IRPT, and the outcomes of empirical investigations producing conflicting evidence, the desire to investigate the issue in the African context necessitated a thorough empirical investigation of four African countries (South Africa, Botswana, Nigeria and Zambia). This study not only extended the investigation of the issue to the African context, but it merged different IRPT measurement techniques that had not been jointly applied to this particular issue, namely; Symmetric and Asymmetric Error Correction Models, Mean Adjustment Lags, Ordinary Least Squares estimations and Autoregressive Distributed Lag models. These measures of the IRPT were compared with three firm concentration ratios on two different levels of analysis, one, over the entire period and, another, through eight year rolling windows. The results reveal that bank concentration can sometimes be related to the speed and magnitude of the IRPT but that these relationships are not consistent amongst the countries, over the entire sample period or across the two levels of analysis, suggesting reasons why empirical results have arrived at contrasting conclusions. The results revealed more evidence of a relationship between bank concentration and the magnitude of the IRPT than between bank concentration and the speed of the IRPT. Furthermore, where relationships were identified there was evidence supporting both the structure conduct performance hypothesis and the competing efficient market hypothesis as the true representation of the relationship between bank concentration and the IRPT. The key implication of the result for African countries is that increased bank concentration through bank consolidation programmes should not be automatically regarded as detrimental to the effective implementation of monetary policy through the IRPT. Consequently,banking sector regulation need not stifle bank consolidation and growth to preserve monetary policy effectiveness. Rather, since the relationship cannot be neatly represented by a single theory or hypothesis each country must determine its own interaction between bank concentration and its IRPT before policies regarding the banking sector concentration and effective monetary policy, through the use of official interest rates, are determined.
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- Date Issued: 2010
The relationship between leadership style and employee engagement in Sasol Gas, South Africa
- Authors: Duma, Thobile
- Date: 2010
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/64034 , vital:28524
- Description: The main purpose of this study was to determine whether there is a significant relationship between leadership styles of Sasol Gas leaders and their followers’ level of employee engagement. The instruments used in the study were the Multifactor Leadership Questionnaire (MLQ) (Form 5X) and the Utrecht Work Engagement Scale (UWES 9). The MLQ (5X) was completed by the followers and leaders of Sasol Gas to determine whether Sasol Gas leaders use transactional, transformational and/or laissez-faire leadership styles. The work engagement instrument was completed by each follower to determine current levels of employee engagement. Descriptive statistics were obtained and correlations completed for the data to determine whether the different leadership styles exhibit different levels of engagement. The MLQ survey results indicate that leaders of Sasol Gas have more transformational than transactional leadership styles. The UWES 9 measured the three factors of vigour, dedication, and absorption; dedication had the highest mean compared to vigour and absorption, indicating that Sasol Gas employees strongly identify themselves with their work because it is experienced as meaningful, inspiring, and challenging. This research found a statistically significant, albeit weak, relationship between transformational and transactional leadership styles and employee engagement. This is a positive reflection of the current Sasol Gas leaders because empirical evidence shows that transformational leadership behaviours are more successful for attaining and fulfilling goals during organisational change.
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- Date Issued: 2010
The relationship between learning styles and perceptions of blended learning : a case study of third-year Environmental Science students at Rhodes University
- Authors: Gambiza, James
- Date: 2010
- Subjects: Blended learning , Education, Higher -- Computer-assisted instruction , Environmental sciences -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2013 , http://hdl.handle.net/10962/d1016352
- Description: The use of blended learning to support teaching and learning is growing globally. Few studies, however, have investigated the relation between students’ learning styles and their perceptions of blended learning. This study used a case-study approach to investigate third year Environmental Science students’ learning styles and perceptions of the online component of blended learning at Rhodes University. Vermunt’s inventory of learning’s styles instrument was used to assess the students’ learning styles. Students’ perceptions of online learning were assessed using an 84-item online experience questionnaire. Multivariate cluster analyses based on students’ learning styles, perceptions of online learning and final coursework marks were done. The correlation between learning styles and perceptions of blended learning was assessed. Students had been using computers for about 10 years. About 91% of students owned computers and 50% had access to Internet at home or in their residences. Internet and email were the most commonly used tools for student learning averaging about at least six times per week. Three of Vermunt’s four learning styles were identified. These were the meaning-directed, application-directed and reproduction-directed styles. The undirected learning style was absent. A major finding of this study was the dissonance in learning styles of students. For example, students with the meaning-directed style also scored high on reproduction-directed style. Students combined deep approaches with memorisation when learning. I developed an instrument consisting of seven scales that described students’ perceptions of online learning. The scales were epistemological judgements, multiple sources of information, learning goals, relevance, Internet experience, appropriate tool and student interaction. There was high within scale variability in students’ perceptions of online learning. The perception that the Internet provided multiple sources of information was positively associated with advanced models of epistemology that support the construction of knowledge. There was dissonance between the perception of the Internet as enhancing epistemological judgements and some components of learning style. A perception of epistemological judgements was positively correlated with both deep and surface cognitive processing strategies.
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- Date Issued: 2010
The relationship between organisational culture and financial performance: an exploratory study in a selected financial institution in South Africa
- Authors: Swanepoel, Sybel
- Date: 2010
- Subjects: Corporate culture -- South Africa Financial institutions -- South Africa Banks and banking -- South Africa Economic development -- South Africa Organizational behavior -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:760 , http://hdl.handle.net/10962/d1003881
- Description: This research investigates the relationship between organisational culture and financial performance in a selected financial services institution in South Africa. The banking sector as part of the financial services industry contributes to economic growth in the economy. The banking sector in South Africa is highly concentrated, but also highly competitive. It is important for banks to retain their competitiveness and increased global competition places further pressure on banks to perform financially in order to satisfy the demands of shareholders. The literature reviewed and previous studies both suggest that organisational culture is an important variable that influences organisational performance. For purposes of this research, organisational performance will be measured in terms of financial performance. The concepts of organisational culture and financial performance are discussed and a questionnaire based on Hall’s (1988) theory of organisational competence is used to determine the strength of the levels of the dimensions of competence as indicators of organisational culture within the selected financial institution. The financial performance of the branches within the organisation is determined by calculating certain selected financial performance ratios, namely cost-to-income ratio, cumulative leverage and contribution per employee. A correlation analysis is conducted in order to establish whether there is a statistically significant relationship between organisational culture and financial performance. A conclusion is drawn that there is a statistically significant relationship between the organisational culture and the financial performance of the branches of the selected institution and recommendations are made as to how financial performance can be improved by strengthening the dimensions of competence as indicators of organisational culture. These recommendations include specific actions that can be taken by leaders to improve commitment, collaboration and creativity.
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- Date Issued: 2010
The representation of women's reproductive rights in the American feminist blogosphere: an analysis of the debate around women's reproductive rights and abortion legislation in response to the reformation of the United States health care system in 2009/10
- Authors: Yelverton, Brittany
- Date: 2010
- Subjects: Abortion -- Law and legislation -- United States Reproductive rights -- Law and legislation -- United States Fertility -- Law and legislation -- United States Feminism Blogs -- United States Health care reform -- United States -- 21st century Women -- Blogs -- United States Social change -- United States Discourse analysis Feministing Jezebel
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3494 , http://hdl.handle.net/10962/d1002949
- Description: This study investigates the representation of women's reproductive rights in the feminist blogopshere during 2009/10 United States health care reform. Focusing on two purposively selected feminist blogsites - Feministing and Jezebel- it critically examines the discursive and rhetorical strategies employed by feminist bloggers to contest the erosion of women's reproductive rights as proposed in health care reform legislation. While the reformation of the U.S. health care system was a lengthy process, my analysis is confined to feminist blog posts published in November 2009, December 2009 and March 2010. These three months have been designated as they are roughly representative of three pivotal stages in health care reform: the drafting of the House of Representatives health care reform bill and Stupak Amendment in November 2009, the creation of the Senate health care bill inclusive of the Nelson compromise in December 2009, and the passage of the finalised health care reform bill, the Patient Protection and Affordable Care Act and supplementary executive order, in March 2010. This study is informed by feminist poststructuralist theory and Foucault's conceptions of discourse and power - an appropriate framework for identifying and analysing the unequal power relations that exist between men and women in patriarchal societies. Foucault conceives of discourse as both socially constituted and constitutive and contends that through the constitution of knowledge, discourses designate acceptable ways of talking, writing, and behaving, while simultaneously restricting and prohibiting alternatives, thereby granting power and authority to specific discourses. However, Foucault also stresses the multi-directionality of power and asserts that though hegemonic discourses are privileged over others, power lays in discursive practice at all social sites; hence the socially and politically transformative power of contesting discourses. Critical discourse analysis is informed by this critical theory of language and regards the use of language as a form of social practice located within its specific historical context. Therefore, it is through engaging in the struggle over meaning and producing different 'truths' through the reappropriation of language that the possibility of social change exists. Employing narrative, linguistic and rhetorical analysis, this study identifies the discursive strategies and tactics utilised by feminist bloggers to combat and contest anti-choice health care legislation. The study further seeks to determine how arguments supportive of women's reproductive rights are framed and how feminist discourses are privileged while patriarchal discourse is contested. Drawing on public sphere theory, I argue that the feminist blogosphere constitutes a counter-public which facili tates the articulation and circulation of marginalised and counter-discourses. I conclude this study by examining the feminist blogopshere's role in promoting political change and transformation through alternative representations of women and their reproductive rights.
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- Date Issued: 2010
The role of APPRAISAL in the National Research Foundation (NRF) rating system evaluation and instruction in peer reviewer reports
- Authors: Marshall, Christine Louise
- Date: 2010
- Subjects: Veterinary medicine -- Research -- Evaluation Discourse analysis Politeness (Linguistics) Accreditation (Education) -- South Africa Quality assurance -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2356 , http://hdl.handle.net/10962/d1002638
- Description: This thesis reports on two aspects of interpersonal meaning in peer reviewer reports for eleven researchers in the Animal and Veterinary Sciences awarded NRF ratings in A1, B1, C1 and Y1 rating categories. These aspects are the evaluation of the researcher applying for a rating, and the instruction to the NRF as to the rating the researcher ought to receive. A full APPRAISAL Analysis (Martin & White 2005) complemented by an investigation of politeness strategies (Myers 1989) is used to analyse the reports and show how the various systems of interpersonal meaning co-function and to what effect. The analysis reveals that there are clear differences between the evaluative and instructive language used in the reports. Those for the A1 rated researchers are characterised by only positive evaluations of the applicant, frequently strengthened in terms of Graduation and contracted in terms of Engagement. Overall there is less Engagement and politeness in these reports rendering them more ‘factual’ than the reports for the other rating categories. The A1 rated researcher is therefore construed as being, incontestably, a leader in his/her field of research, worthy of a top rating. The reports for the B1 and C1 rated researchers are characterised by the increasing presence of negative evaluations. In addition, there are more instances of softened/downscaled Graduation, dialogic expansion and deference politeness, showing that there is more perceived contention about the evaluations made. The reports for the Y1 rated researchers (a category for young researchers) focus on the applicant’s demonstrated potential to become a leader in the field. In addition to a high incidence of negative evaluations, downscaled Graduation, dialogic expansion and deference politeness, the Y1 reports are also characterised by a high incidence of advice and suggestions from the reviewers concerning the applicant’s work and standing. At a broader level, the analysis reveals that the language used in the reports has a profound influence on the outcome of the rating process. The reports are crucial, not only for evaluating the applicant but, also, more subtly, in directing the NRF towards a specific rating category. It offers insights into what is valued in the scientific community, what is considered quality research, and what leads to international recognition. The research also adds uniquely to current thinking about the language of science and, more particularly, highlights the nuanced understanding of evaluative and instructive language in the reports that is possible if one draws on the full APPRAISAL framework, and insights into politeness behaviour.
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- Date Issued: 2010
The role of strategic leadership in Coega Development Corporation: a case study
- Authors: Davids, Mogamad Sadiek
- Date: 2010
- Subjects: Coega Development Corporation Industrial development projects -- South Africa -- Eastern Cape -- Case studies Leadership -- South Africa -- Eastern Cape -- Case studies Strategic planning -- South Africa -- Eastern Cape -- Case studies Organizational behavior -- South Africa -- Eastern Cape -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:763 , http://hdl.handle.net/10962/d1003884
- Description: South Africa became a democracy after its election in April 1994. Thereafter, the country faced the daunting task of trying to fast-track economic growth and addressing social challenges. The Department of Trade and Industry was mandated by the newly elected government to spearhead economic development in order to address these challenges. Trade policy instruments such as industrial development zones formed part of government’s strategic economic instruments to achieve economic reform. The Coega Industrial Development Zone (CIDZ) near Port Elizabeth was one of many economic development zones created principally to promote export orientated manufacturing. The Coega Development Corporation (CDC) was registered as a company to develop, operate and manage the CIDZ. The literature suggests that strategic leadership is important for organizational success. Strategic leadership is described as the ability to influence others to make day-to-day voluntary decisions that enhance long-term viability while maintaining short term financial stability. Literature further suggests that strategic leaders deal with the evolution of organizations and their changing aims and transform them through their capabilities and strategic leadership roles such as being a figurehead, spokesperson, team builder, design school planner and so on. The aim of this research is to analyse the role of strategic leadership with the objectives to ascertain whether strategic leadership contributed to the success of the development of CDC, and identify possible challenges they are confronted with in the execution of their leadership duties. This research was conducted from an interpretivist perspective as the researcher attempted to develop insight into how the strategic leadership of CDC viewed and understood their role. The strategic leadership of CDC, who were the focus of this study, consisted of the executive management team of the organization, including the Chief Executive Officer (CEO). The research design was in the form of a case study of the CDC leadership, with data collected through semi-structured interviews and documents. The most prominent roles exercised by the leadership of CDC included creating a vision and strategy development and inculcating a teamwork corporate culture. Other roles identified include that of team builder, fostering innovation and developing human capital etc. A lack of stakeholder management as well as managing the culture of the organization as it expands and grows, remain critical challenges. Finally recommendations are made together with suggestions for future research.
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- Date Issued: 2010
The role of teachers' resource centres from the perspective of school managers and teachers
- Authors: Mbambo, Markus S
- Date: 2010
- Subjects: Education -- Namibia Teaching -- Aids and devices -- Namibia Resource programs (Education) -- Namibia Teachers -- Namibia -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1754 , http://hdl.handle.net/10962/d1003638
- Description: This study aimed to investigate the role played by the Teachers’ Resource Centre (TRC) in Namibia in helping schools to provide quality education. The TRC concept began in Britain in the 1960s, where it was introduced as a means of supporting the professional development of teachers and giving them access to a range of educational resources. From the 1970s, the concept was promoted further afield as an effective strategy for dealing with teachers’ needs. TRCs emerged in Namibia in the 1980s under the auspices of the then Department of Education of the South African government. By 1989, only four TRCs were in existence, namely, Katutura, Tsumeb, Otjiwarongo and Rundu, plus one in the whites-only training college in Windhoek. In September 1991, the Ministry of Education and Culture (MEC) in Namibia produced a five-year plan that led to the diversification of the TRC network in Namibia. Yet, despite the now widespread existence of TRCs, little is known of whether and to what extent their services are helping teachers to provide quality education. This constitutes a gap in the literature that this study hopes in part to fill. The study was conducted using a case study approach in three schools in the Kavango region of Namibia. It made use of questionnaires, interviews, focus group discussions and data analysis to gather and interpret data. The study’s finding is that TRCs are indeed beneficial to schools in their vicinity, despite their current limited capacities. However, TRCs should be better able to redress the poor quality of education in many schools due to a lack of resources, de-motivated teachers and other factors. This study therefore recommends that enough funds be made available for the TRCs to acquire the resources they need adequately to support quality educational processes. Furthermore, the study found that it is imperative for individuals in TRCs and schools to learn how to facilitate relevant transformation in their organisations’ efficiency and effectiveness. Thus the study recommends a transformational leadership approach as most appropriate for managing learning and bringing about successful change in these organisations. The significance of this research is that it sheds some light on the effectiveness of TRCs as a strategy for supporting teachers in the delivery of quality teaching. It also suggests potential areas in which stakeholders might usefully cooperate in their endeavours to realise quality education.
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- Date Issued: 2010
The taxonomy, life-history and population dynamics of blacktail, Diplodus Capensis (Perciformes: Sparidae), in southern Angola
- Authors: Richardson, Timothy John
- Date: 2010
- Subjects: Diplodus -- Angola , Perciformes -- Angola , Sparidae -- Angola , Fish populations -- Angola , Fishes -- Classification -- Angola , Fisheries -- Angola
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5324 , http://hdl.handle.net/10962/d1005170 , Diplodus -- Angola , Perciformes -- Angola , Sparidae -- Angola , Fish populations -- Angola , Fishes -- Classification -- Angola , Fisheries -- Angola
- Description: The blacktail, Diplodus capensis, is an inshore sparid fish distributed from Mozambique to Angola. This species forms an important component of coastal fisheries within its distribution, one being the subsistence handline fishery in southern Angola. With this fishery being critically important to the livelihoods of local communities, a biological study and stock assessment was conducted to provide information for the management of this species in southern Angola. However, with molecular evidence suggesting that the Benguela current may have separated the southern African populations of many inshore fish species over two million years ago, a morphological, taxonomic analysis was considered necessary to first investigate whether there was evidence for allopatry in this species. A total of 46 morphometric measurements and 18 counts were carried out on specimens collected from various locations in southern Angola and South Africa. Results were analysed using multi-dimensional scaling (MDS) and the significance of clusters was tested using analysis of similarities (ANOSIM). Biological samples of D. capensis were collected monthly from an unexploited area from April 2008 to March 2009. Additional biological samples were collected from the subsistence fishers in an exploited area during May, June and December 2009. Standard biological laboratory techniques were employed for the lifehistory comparison between the exploited and unexploited area. A per-recruit analysis was conducted using the life-history parameters from both areas in order to assess the current status of the subsistence fishery and to investigate the potential short-falls of the per-recruit assessment approach. The morphometric comparison showed that there was not sufficient evidence for speciation between the southern Angolan and South African populations of D. capensis. There was, however, sufficient morphological evidence to suggest that these populations are separate stocks. This indicated that the existing reference points on which the management of the South African population is based are unsuitable for the Angolan population. Diplodus capensis in southern Angola is omnivorous, feeding predominantly on algae, barnacles and mussels. An ontogenetic shift from algae to barnacles and mussels was correlated with allometric growth patterns in their feeding apparatus. This species is a rudimentary hermaphrodite in southern Angola with peak spawning in June and July. The overall sex ratio (M: F) was 1: 4.7 in the unexploited area and 50% maturity was attained at 149.5mm FL and five years. Diplodus capensis in southern Angola exhibits very slow growth with the maximum age observed being 31 years (validated using mark recapture of chemically injected fish). Females [L(t) = 419.5(1-e⁻°·°⁴⁵⁽t⁻³·⁴ ⁾)] grew significantly faster (LRT, p < 0.05) than males [L(t) = 297.4(1-e⁻°·°⁷⁷⁽t⁻²·⁷⁾)], and females dominated the larger size classes and older age classes. In the exploited area, the length and age frequencies were severely truncated, the maximum observed age was greatly reduced (17 years) and the sex ratio was less female biased at 1: 2.2. Although there was no evidence for a physiological response to exploitation through alterations in growth or size/age at sexual maturity between the two areas, there was an increase in the proportion of small females in the exploited area, which may have been a compensatory response for the loss of large females. A combination of an underestimate of longevity, different estimates of the Von Bertalanffy growth parameters and overestimates of the natural mortality rate in the exploited population resulted in a 92% underestimate of the pristine spawner biomass-per-recruit (SBR) value. An assessment based on the actual pristine SBR estimate from the unexploited area revealed that the subsistence fishery had actually reduced D. capensis to 20% of its pristine SBR levels and highlighted the value of pre-exploitation life-history information for the application of per-recruit models. This study has shown that D. capensis in southern Angola displays life-history characteristics that render it susceptible to overexploitation, even at low levels of fishing pressure. The current lack of infrastructure and enforcement capacity in the fisheries department of Angola renders traditional linefish regulatory tools, such as size limits, bag limits and closed seasons, inappropriate. Therefore, suitably designed marine protected areas are recommended as the best management option for this species.
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- Date Issued: 2010
The ultrastructure and histology of the defensive epidermal glands of some marine pulmonates
- Authors: Pinchuck, Shirley Clare
- Date: 2010
- Subjects: Snails -- Histology , Snails -- Physiology , Snails -- Cytology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5793 , http://hdl.handle.net/10962/d1005481 , Snails -- Histology , Snails -- Physiology , Snails -- Cytology
- Description: Histology and electron microscopy were used to describe and compare the structure of the dorso-lateral pedal defensive glands of three species of marine Basommatophora, Siphonaria capensis, S. serrata and S. gigas. All three species possessed multi-cellular glands that were larger and most abundant in S. capensis. In S. capensis and S. serrata, defensive glands were composed of two types (type I and II) of large secretory cells filled with product and some irregularly shaped support cells that surrounded a central lumen. The product of both cell types was produced by organelles confined to the bases of the cells. The entire gland was surrounded by a well developed layer of smooth muscle and collagen. Type I cells stained positively for neutral and sulphated mucins, and at the transmission electron microscope level the product had a reticulated appearance. By contrast type II gland cells stained very positively for acidic mucins and the secretory product was formed as large granular vesicles. The product from both types of cell, which appeared to be secreted by holocrine secretion, mixed in the lumen of the duct. Individuals of Siphonaria gigas had two types of lateral pedal glands, a large multi-cellular type and a tubular unicellular gland. The multi-cellular glands, which were surrounded by poorly developed muscle, contained one type of gland cell that stained for neutral and sulphated mucins only, as well as some support cells. The tubular glands contained a heterogeneous product that stained very positively for neutral and sulphated mucins. In addition two species of shell-less marine Systellommatophorans, Onchidella capensis and O. hildae, were examined. Onchidellids also posses large marginal, multi-cellular, epidermal glands that produce a repugnatorial secretion. Like the multi-cellular epidermal glands of siphonariids, those of onchidellids are surrounded by layers of smooth muscle. The muscular capsule was particularly well developed in both species of onchidellid, but more so in O. hildae. In addition, this study has shown that unlike siphonariids, muscle fibres run between the gland cells of O. capensis and O. hildae. Unlike siphonariids, onchidellids have a layer of epithelial cells lining the lumen of the gland. The well developed muscle layer and the strands of muscle running between the different gland cells indicates that the glands can be constricted to forcibly propel their secretions along the length of the duct and away from the body of the animal. Based on their product, glands of O. capensis were comprised of five different types of secretory cell and O. hildae only four. Histological and histochemical staining of the glands of showed that the secretory product is largely made up of acidic mucopolysaccharides and neutral and sulphated mucins. A single species from the order Eupulmonata, Trimusculus costatus, was examined and the glands were very different to the species from the siphonariids and onchidellids. Trimusculus costatus does not have large multi-cellular glands encapsulated in a well developed muscle layer, but based on their cell contents, three different types of large unicellular gland cell can be recognised. The glands of T. costatus gave positive results for acid, neutral and sulphated mucins, but negative results for carboxylated mucin. It is possible that the mucous secreted by T. costatus is also an anti-bacterial agent and whilst not totally eliminating bacteria may prevent the accumulation of epibionts on these sedentary limpets. The acidic or sulphated nature of the secretions may help in this role. The defensive mucous secretions of Siphonaria and Onchidella contain polypropionate derivatives, whilst the active ingredients of Trimusculus mucus have been identified as labdane diterpenes, similar to those produced by opisthobranchs. The structure of the glands thought to produce these repungnatorial secretions is very different, with the glands of T. costatus resembling those of the opisthobranchs.
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- Date Issued: 2010