Does the growth of structure affect our dynamical models of the Universe? The averaging, backreaction, and fitting problems in cosmology
- Authors: Clarkson, C , Ellis, G , Larena, Julien , Umeh, O
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6791 , http://hdl.handle.net/10962/d1006944
- Description: Structure occurs over a vast range of scales in the Universe. Our large-scale cosmological models are coarse-grained representations of what exists, which have much less structure than there really is. An important problem for cosmology is determining the influence the small-scale structure in the Universe has on its large-scale dynamics and observations. Is there a significant, general relativistic, backreaction effect from averaging over structure? One issue is whether the process of smoothing over structure can contribute to an acceleration term and so alter the apparent value of the cosmological constant. If this is not the case, are there other aspects of concordance cosmology that are affected by backreaction effects? Despite much progress, this 'averaging problem' is still unanswered, but it cannot be ignored in an era of precision cosmology, for instance it may affect aspects of baryon acoustic oscillation observations.
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- Date Issued: 2011
3000 miles from home: a new Gastrosericus baobabicus Pulawski, 1995 (Hymenoptera, Larridae) distribution record highlights that the Sahel has a distinct entomofaunal signature
- Authors: Clitheroe, C-L , Villet, Martin H
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6846 , http://hdl.handle.net/10962/d1011099
- Description: [from introduction] On October 30, 1953, an unidentified female wasp (Fig. 1) was collected from ‘Belet Uen, Somaliland’ (= Beledweyne, 4°44’N 45°12’E), situated in the valley of the Shebelle River, HiraanProvince,Somalia. It was deposited in the aculeate Hymenoptera collection of the Albany Museum, Grahamstown by D. Greathead prior to 1968. Apart from the words ‘Somaliland’ and ‘Desert Locust Survey’ the label is handwritten and the collector’snameis not recorded. Greathead’s sister, S. Gess (Albany Museum), deciphered the label and stated that he had worked for the Desert Locust Survey, investigating the natural enemies of locusts and had been in Somalia (then Somaliland) at that time (Murphy & Cock 2007). The specimen was sent in 2004 by F. Gess to W. Pulawski, who determined it as Gastrosericus baobabicus Pulawski, 1995. Gastrosericus species prey on spiders and a variety of small insects (Pulawski 1995), including Orthoptera (Krombein & Pulawski 1986), so it is likely that Greathead collected the specimen in connection with his interest in the insect enemies of Acridoidea (Orthoptera) (Greathead 1962).
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- Date Issued: 2011
Microelectrochemical patterning of gold surfaces using 4-azidobenzenediazonium and scanning electrochemical microscopy
- Authors: Coates, Megan , Cabet, Eva , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247926 , vital:51630 , xlink:href="https://doi.org/10.1016/j.elecom.2010.11.037"
- Description: This work describes for the first time the possibility of performing local micro electrochemical grafting of a gold substrate by 4-azidobenzenediazonium by SECM in a single and simple one step without complications from adsorption. The electrografted spots of diazonium were performed by positioning a Pt tip at a given distance above the gold substrate and the SECM was used in a three-electrode configuration (the Pt tip serving as the microanode) in acetonitrile containing 5 mM 4-azidobenzenediazonium and 0.1 M Bu4NBF4 during 10 ms. The dimensions of the derivatized areas of the substrates were finely tuned by using different experimental conditions (tip distance above the substrate, tip diameter, presence or absence of supporting electrolyte). The use of the azido-derivated diazonium molecule and these preliminary results open the gate to important applications and developments devoted to the local micro functionalization of electrodes by thin layers that allow the implementation of the emerging and attractive interfacial click reaction.
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- Date Issued: 2011
Cultural importance of non-timber forest products: opportunities they pose for bio-cultural diversity in dynamic societies
- Authors: Cocks, Michelle L , López, Citlalli , Dold, Anthony P
- Date: 2011
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141453 , vital:37973 , ISBN 9783642179822 , DOI: 10.1007/978-3-642-17983-9_5
- Description: There is an increasing awareness that monetary value does not fully represent the complete value and significance of NTFPs. Consequently, there is growing interest in the cultural dimensions of biodiversity and the role that it plays in human well-being. This chapter presents two case studies, one on traditional brooms in South Africa, and the other on amate paper in Mexico, to demonstrate the importance of cultural values on driving demand for NTFPs. Because cultural values are so deeply embedded, the demand for culturally valued NTFPs continue across the rural-urban divide, and are maintained even by modernising urban communities. This poses particular challenges, not only for conservation of the NTFPs, but also to sustain cultural diversity in a rapidly changing world.
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- Date Issued: 2011
The role of eutrophication in the biological control of water hyacinth, Eichhornia crassipes, in South Africa
- Authors: Coetzee, Julie A , Hill, Martin P
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69263 , vital:29474 , https://doi.org/10.1007/s10526-011-9426-y
- Description: South Africa has some of the most eutrophic aquatic systems in the world, as a result of the adoption of an unnecessarily high 1 mg l-1 phosphorus (P) standard for all water treatment works in the 1970 s. The floating aquatic macrophyte, water hyacinth (Eichhornia crassipes (Mart.) Solms (Pontederiaceae), has taken advantage of these nutrient rich systems, becoming highly invasive and damaging. Despite the implementation of a biological control programme in South Africa, water hyacinth remains the worst aquatic weed. A meta-analysis of published and unpublished laboratory studies that investigated the combined effect of P and nitrogen (N) water nutrient concentration and control agent herbivory showed that water nutrient status was more important than herbivory in water hyacinth growth. Analysis of long-term field data collected monthly from 14 sites around South Africa between 2004 and 2005 supported these findings. Therefore, the first step in any water hyacinth control programme should be to reduce the nutrient status of the water body.
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- Date Issued: 2011
'I want to tell the story again': re-telling in selected novels by Jeanette Winterson and Alan Warner
- Authors: Collett, Jenna Lara
- Date: 2011
- Subjects: Warner, Alan Criticism and interpretation Winterson, Jeanette, 1959- -- Criticism and interpretation English fiction -- 20th century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2248 , http://hdl.handle.net/10962/d1002291
- Description: This thesis investigates acts of ‘re-telling’ in four selected novels by Jeanette Winterson and Alan Warner.Re-telling, as I have defined it, refers to the re-imagining and re-writing of existing narratives from mythology, fairy tale, and folktale, as well as the re-visioning of scientific discourses and historiography. I argue that this re-telling is representative of a contemporary cultural phenomenon, and is evidence of a postmodern genre that some literary theorists have termed re-visionary fiction. Despite the prevalent re-telling of canonical stories throughout literary history, there is much evidence for the emergence of a specifically contemporary trend of re-visionary literature. Part One of this thesis comprises two chapters which deal with Winterson’s Sexing the Cherry (1989) and Weight (2005) respectively. In these chapters, I argue that, although the feminist and historiographic elements of her work are significant, there exist further motivations for Winterson’s acts of re-telling in both Sexing the Cherry and Weight. In Chapter One, I analyse Winterson’s subversion and re-imagining of historiography, as well as her re-telling of fairy tale, in Sexing the Cherry. Chapter Two provides a discussion of Winterson’s re-telling of the myth of Atlas from Greek mythology, in which she draws on the discourses of science, technology, and autobiography, in Weight. Part Two focuses on Warner’s first two novels, Morvern Callar (1995) and These Demented Lands (1997). In both novels, Warner re-imagines aspects of Christian, Celtic and pagan mythology in order to debunk the validity of biblical archetypes and narratives in a contemporary working-class setting, as well as to endow his protagonist with goddess-like or mythical sensibilities. Chapter Three deals predominantly with Warner’s use of language, which I argue is central to his blending of mythological and contemporary content, while Chapter Four analyses his use of myth in these two novels. This thesis argues that while both Winterson and Warner share many of the aims associated with contemporary re-visionary fiction, their novels also exceed the boundaries of the genre in various ways. Winterson and Warner may, therefore, represent a new class of re-visionary writers, whose aim is not solely to subvert the pre-text but to draw on its generic discourses and thematic conventions in order to demonstrate the generic and discursive possibilities inherent in the act of re-telling.
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- Date Issued: 2011
Synthesis and evaluation of novel inhibitors of 1-Deoxy-D-xylolose-5-phosphate reductoisomerase as potential antimalarials
- Authors: Conibear, Anne Claire
- Date: 2013-07-19
- Subjects: Antimalarials -- Development , Malaria -- Chemotherapy , Drug development , Enzyme kinetics , Phosphate esters
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4451 , http://hdl.handle.net/10962/d1008282 , Antimalarials -- Development , Malaria -- Chemotherapy , Drug development , Enzyme kinetics , Phosphate esters
- Description: Malaria continues to be an enormous health-threat in the developing world and the emergence of drug resistance has further compounded the problem. The parasite-specific enzyme, 1-deoxY-D-xylulose-S-phosphate reductoisomerase (DXR), has recently been validated as a promising antimalarial drug target. The present study comprises a combination of synthetic, physical organic, computer modelling and bioassay techniques directed towards the development of novel DXR inhibitors. A range of 2-heteroarylamino-2-oxoethyl- and 2- heteroarylamino-2-oxopropyl phosphonate esters and their corresponding phosphonic acid salts have been synthesised as analogues of the highly active DXR inhibitor, fosmidomycin. Treatment of the heteroarylamino precursors with chloroacetyl chloride or chloropropionyl chloride afforded chloroamide intermediates, Arbuzov reactions of which led to the corresponding diethyl phosphonate esters. Hydrolysis of the esters has been effected using bromotrimethylsilane. Twenty-four new compounds have been prepared and fully characterised using elemental (HRMS or combustion) and spectroscopic (1- and 2-D NMR and IR) analysis. A 31p NMR kinetic study has been carried out on the two-step silylation reaction involved in the hydrolysis of the phosphonate esters and has provided activation parameters for the reaction. The kinetic analysis was refined using a computational method to give an improved fit with the experimental data. Saturation transfer difference (STD) NMR analysis, computer-simulated docking and enzyme inhibition assays have been used to evaluate the enzyme-binding and -inhibition potential of the synthesised ligands. Minimal to moderate inhibitory activity has been observed and several structure-activity relationships have been identified. In silica exploration of the DXR active site has revealed an additional binding pocket and information on the topology of the active site has led to the de novo design of a new series of potential ligands. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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Entrepreneurship education at a FET college
- Authors: Cook, Vania Saretta
- Date: 2011
- Subjects: Entrepreneurship -- Study and teaching , Business education
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8637 , http://hdl.handle.net/10948/d1008071 , Entrepreneurship -- Study and teaching , Business education
- Description: The previous economic structure in South Africa was well served by the FET College institutions in that they provided a resource pool for large companies and organisations. This however, developed a student mindset of becoming an employee instead of the employer of an organisation. With an economy in transition, privately owned companies or organisations now account for an increasing proportion of economic development. Hence, FET Colleges need to redefine their role in the economy and society, specifically in the type of entrepreneurship courses they offer. This study examines the provision of entrepreneurship education at a FET College in the Eastern Cape with special reference to the levels of provision, support mechanisms, course objectives, contents, teaching and assessment methods to ascertain whether they are appropriately developed to prepare students for entrepreneurship as a career option. This study followed a qualitative research paradigm, implementing a case study approach during the research. In order to analyse the above, the New Venture Creation and Entrepreneurship and Business Management students were selected for this study. Data were collected by handing out questionnaires to a sample of 200 students to assess entrepreneurship courses and pedagogies. The results of this study, indicate that entrepreneurship education at a specific FET College is not enabling the students with sufficient knowledge and skills to start their own business. The results indicate a low level of entrepreneurship education and a weak standing of entrepreneurship courses, which tend to only be part of the Finance course offered within the Business Studies Department at a FET College. Contributing factors to this low level of entrepreneurship education have been identified by lack of support mechanisms by management, the theoretical orientation of entrepreneurship curriculum, teaching methods and assessment of tasks. Based on these findings, it is strongly suggested that this FET College should: (1) develop specialised entrepreneurship programmes for all students; (2) receive special funding for entrepreneurship education; (3) integrate experiential learning in the curriculum; and (4) give special consideration to training entrepreneurship educators.
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- Date Issued: 2011
The lived experience of meaning in life and satisfaction with life among older adults
- Authors: Cooper, Holly
- Date: 2011
- Subjects: Meaning (Psychology) , Satisfaction , Old age , Old age homes
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/4398 , vital:20595
- Description: The purpose of the study was to explore and describe the meaning in life and satisfaction with life of the elderly living in the old age institutions.
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- Date Issued: 2011
Hsp90α/β associates with the GSK3β/axin1/phospho-β-catenin complex in the human MCF-7 epithelial breast cancer model:
- Authors: Cooper, Leanne C , Prinsloo, Earl , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165096 , vital:41208 , DOI: 10.1016/j.bbrc.2011.08.136
- Description: Hsp90α/β, the signal transduction chaperone, maintains intracellular communication in normal, stem, and cancer cells. The well characterised association of Hsp90α/β with its client kinases form the framework of multiple signalling networks. GSK3β, a known Hsp90α/β client, mediates β-catenin phosphorylation as part of a cytoplasmic destruction complex which targets phospho-β-catenin to the 26S proteasome. The canonical Wnt/β-catenin pathway promotes stem cell self-renewal as well as oncogenesis. The degree of Hsp90α/β involvement in Wnt/β-catenin signalling needs clarification. Here, we describe the association of Hsp90α/β with GSK3β, β-catenin, phospho-β-catenin and the molecular scaffold, axin1, in the human MCF-7 epithelial breast cancer cell model using selective inhibition of Hsp90α/β, confocal laser scanning microscopy and immunoprecipitation. Our findings suggest that Hsp90α/β modulates the phosphorylation of β-catenin by interaction in common complex with GSK3β/axin1/β-catenin.
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- Date Issued: 2011
The role of Hsp90 in the Wnt pathway of MCF7 breast cancer cells
- Authors: Cooper, Leanne Claire
- Date: 2011
- Subjects: Cancer -- Treatment , Heat shock proteins , Cancer cells , Molecular chaperones
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3985 , http://hdl.handle.net/10962/d1004044 , Cancer -- Treatment , Heat shock proteins , Cancer cells , Molecular chaperones
- Description: Breast cancer is one of the most common forms of cancer in not only South African women, but women all over the world. The molecular chaperone heat shock protein 90 (HSP90) is upregulated in cancer and is almost exclusively associated with proteins involved in intracellular signal transduction, thus it plays an important role in signalling pathways within the cell. In cancer, there is an aberrant activation of the Wnt signaling pathway, which results in stabilized β-catenin being able to translocate to the nucleus where it can trigger the transcription of oncogenes found to be involved in the self-renewal of cells. The level of β-catenin is usually kept in check by a destruction complex comprising glycogen synthase kinase 3-beta (GSK-3β), axin1, adenomatous polyposis coli (APC) which phosphorylate β-catenin, resulting in its ubiquitination and degradation. HSP90 has been found to be associated with GSK-3β, but whether this association is only transient is debatable. Very little is known about the association of HSP90 with other members of the Wnt pathway in breast cancer. In this study, we have attempted to further identify the direct associations between HSP90 and GSK-3β, β-catenin, p-β-catenin and axin1. Immunofluorescence and confocal microscopy co-localization studies suggested a potential association between HSP90 and these proteins. Treatment with HSP90 inhibitors, 17-AAG and novobiocin resulted in a shift of axin1 to what appeared to be the plasma membrane. The associations of HSP90 with GSK-3β, β-catenin, p-β-catenin and axin1 were confirmed biochemically by co-immunoprecipitation and inhibition using 17-AAG, geldanamycin and novobiocin. We showed, for the first time that HSP90 is associated in a possible complex with β-catenin, p-β-catenin and axin1 therefore is potentially involved in the modulation of p-β-catenin in the Wnt pathway through the stabilization of the destruction complex.
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- Date Issued: 2011
Comfortably numb: Crump unveiled—a review of the 2011 Alan Crump retrospective exhibitio
- Authors: Cooper, Paul S
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147924 , vital:38685 , DOI:10.1080/00043389.2011.11877152
- Description: Writing can at times be difficult. It is not without considerable anxiety that I undertake to write this particular review. Perhaps I should offer a short qualifier: this is not strictly a review but rather a collection of ideas around the works and their arrangement, as well as my own musings and reflections on Crump. I want to pick up on what I identify to be an approach that personalises Crump as a professor, colleague and artist (we find this tone embedded throughout the accompanying exhibition catalogue). 1 I have chosen to structure this essay using a series of trigger headings, some provocative and possibly even inflammatory, others more neutral and concerned with getting to the core of what this retrospective and posthumous show is all about. All the while my thinking is to channel a sense (or lack thereof, as it may turn out) of my own experience of his work and person.
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- Date Issued: 2011
An integrated maintenance management system model for the pharmaceutical industry
- Authors: Coopoosamy, Kribban
- Date: 2011
- Subjects: Pharmaceutical industry -- Management , Pharmaceutical services
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8609 , http://hdl.handle.net/10948/1583 , Pharmaceutical industry -- Management , Pharmaceutical services
- Description: Organisations are continuously seeking for strategies to improve operations and gain competitive advantage. Maintenance tends to be a key management issue for many industrial companies. Maintenance management, being an integral part of manufacturing, can influence competitive companys‟ priorities, such as cost, quality and flexibility, and, hence, business strategy directly. The pharmaceutical industry also faces some unique challenges such as increasingly stringent safety and quality regulations, the effect of innovations in medical science and healthcare and a complex and costly design-to-market process (from product concept and development to market delivery). The industry is also going through turbulent times as it has to cope with challenges common to many other industries, how to deal with increasing competition, hold down costs, and expand. Regulatory compliance is one of the significant industry drivers for pharmaceutical companies. Regulations are enacted by government authorities to ensure public health and safety. The focus of regulation is on quality assurance and control in all areas such as receiving, manufacturing, storing, packaging, despatching and delivering. Apart from the required quality and safety checks, the regulations also mandate extensive record keeping of procedures, processes and systems. This treatise will investigate the maintenance management system of a pharmaceutical company and compare it to best practices. The true name of the pharmaceutical company that will be researched will not be disclosed for confidentiality reasons, instead it will be called My Pharmaceuticals. The company is based in Port Elizabeth. The research consists of a preliminary study to identify the problem areas in the maintenance management system within the company. A literature review of best practices in maintenance management systems combined with an investigation into the best pharmaceutical practices in maintenance management systems and regulatory controls are investigated and a model will be proposed to improve the current situation at the company.
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- Date Issued: 2011
The influence of 1950s fashion photographers, Richard Avedon and Irving Penn, on photographers Matthew Rolston and Steven Meisel
- Authors: Cordier, Astrid
- Date: 2011
- Subjects: Fashion photpgraphy , Photographers -- United States
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:8496 , http://hdl.handle.net/10948/d1008112 , Fashion photpgraphy , Photographers -- United States
- Description: Photography has been used to record and document periods in time, which Wells (2001:19) acknowledges by stating that, “…photographs are records and documents which pin down the changing world of appearance”. Richard Avedon and Irving Penn made a significant contribution to fashion photography during the 1950s but this has seldom been explored in a scholarly way. By defining the characteristics of Avedon and Penn’s work, a possible understanding of their influence on contemporary fashion photographers, Matthew Rolston and Steven Meisel may be determined and so expand on the understanding of the contribution of Avedon and Penn to contemporary fashion photography. Avedon, Penn, Rolston and Meisel’s fashion photographs will be visually analysed to show the similarities and the relevance of 1950s fashion photography to contemporary fashion photography. Paul Martin Lester’s (2003) method of visual analysis will be used as the basis for this analysis. The reason for choosing Lester’s methods of visual analysis is that it can be applied to all fields of visual art and design. Contemporary fashion photography draws on many different stylistic devices and periods in history for its re-invention, so it is important to understand what constitutes the defining characteristics of a stylistic period in history to be able to revisit it in contemporary photography.
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- Date Issued: 2011
Scoring an own goal? The Construction Workers 2010 World Cup Strike
- Authors: Cottle, Eddie
- Date: 2011-10-04
- Subjects: Labour disputes -- South Africa , Strikes and lockouts -- South Africa , Industrial relations -- South Africa
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60018 , vital:27722
- Description: The nationwide strike by 70 000 construction workers between 8 and 15 July 2009 was unprecedented and significant in several respects. This was the first national strike on 2010 World Cup sites by South African construction workers and was therefore an historic event. A second key feature of the strike was the unity displayed by workers and trade unions within a sector organised by several trade unions. Engineering and building workers came out on strike, with the Building Construction & Allied Workers Union (BCAWU) and the National Union of Mineworkers (NUM) standing together as their representative organisations. A third feature of the strike was the widespread sympathy for it by the South African public and media. This was despite it potentially setting back progress with World Cup projects. Fourthly, the pressure placed upon the trade unions' negotiating team by the Ministry of Labour and the FIFA Local Organising Committee (LOC) proved lethal in undermining their, assisting in causing them to dilute their trade union demands and demobilising the national strike.
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- Date Issued: 2011-10-04
Biomechanical, physiological and perceptual responses of three different athlete groups to the cycle-run transition
- Authors: Cripwell, Devin Matthew
- Date: 2011
- Subjects: Biomechanics -- Research , Human mechanics -- Research , Cycling -- Physiological aspects -- Research , Running -- Physiological aspects -- Research , Exercise -- Physiological aspects -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5106 , http://hdl.handle.net/10962/d1005184 , Biomechanics -- Research , Human mechanics -- Research , Cycling -- Physiological aspects -- Research , Running -- Physiological aspects -- Research , Exercise -- Physiological aspects -- Research
- Description: The transition from cycling to running has been identified as one of the key determinants of success in triathlon, as it has been suggested that the cycle may affect subsequent running efficiency such that running performance is significantly altered or reduced. It is also suggested that athletes more adapted to the transition itself, rather than purely running or cycling, may be more efficient during the post-cycle running bout. The current study sought to investigate the effects of prior cycling on subsequent selected biomechanical, physiological and perceptual responses of three different athlete groups. Subjects were selected on the basis of their sporting background, and were divided into three groups – triathletes, cyclists and runners. Experimentation required subjects to perform a seven minute treadmill running protocol at 15km.h⁻¹, during which biomechanical (EMG, Stride rate, Stride length, Vertical acceleration), physiological (HR, VO₂, EE) and perceptual (RPE) responses were recorded. After resting, subjects were required to perform a twenty minute stationary cycle at 70% of maximal aerobic power (previously determined), immediately followed by a second seven minute treadmill running protocol during which the same data were collected and compared to those collected during the first run. Biomechanical responses indicate that the cycle protocol had no effect on the muscle activity or vertical acceleration responses of any of the three subject groups, while the triathlete group significantly altered their gait responses in order to preserve running economy. The triathlete group was the least affected when considering the physiological responses, as running economy was preserved for this group. The runner and cyclist groups were significantly affected by the transition, as running economy decreased significantly for these groups. Perceptual responses indicate that athletes more experienced with the transition may find the transition from cycling to running to be easier than those inexperienced in this transition. It is apparent that a high intensity cycle protocol has limited statistical impact on selected biomechanical responses, while physiological and perceptual responses were altered, during a subsequent run, regardless of athlete type. That said, the ability of transition-trained athletes to transition comfortably between disciplines was highlighted, which may have important performance implications.
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- Date Issued: 2011
Probing the biocompatibility of biomedical interfaces using the Quartz Crystal Microbalance with Dissipation
- Authors: Cromhout, Mary
- Date: 2011
- Subjects: Biomedical materials , Nanostructured materials , Biomedical engineering , Quartz crystal microbalances , Blood proteins , Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4102 , http://hdl.handle.net/10962/d1010660
- Description: The biomedical application of nanotechnology has come into the spotlight, with the promise of ‘personalised’ therapeutics that couple early diagnosis with targeted therapeutic activity. Due to the rapid growth of the biomedical applications of nanoparticles, along with the lack of understanding concerning their interactions with biomolecules, there is a pressing need for the development of standard methods directed at investigating the effect of introducing these unique particles into the human body. The central aim of this research is to establish a platform directed at assessing the biological fate of pioneering therapeutic particulate agents, such as metallophthalocyanines (MPcs) and multi-walled carbon nanotubes (FMWCNTs). In particular, we proposed, that Quartz Crystal Microbalance with Dissipation (QCM-D) technology may be employed to assess the composition of blood protein corona deposited on the therapeutic surface, and subsequently assess the biocompatibility of such particles. The proposed method of protein detection utilises the nanogram sensitivity of QCM-D technology to monitor highly specific antibody-antigen interactions. In particular those interactions which occur when probe antibodies are used to detect adsorbed blood proteins deposited on target particle-modified sensor surfaces. Protein detection analysis was directed toward identification of surface bound human serum albumin, complement factor C3c, and human plasma fibrinogen. Preliminary analysis of generic biomedical surfaces indicated human serum albumin demonstrates a higher binding affinity towards positively charged surfaces (i.e. cysteamine self-assembled monolayer), followed by hydrophobic surfaces. Detection of complement C3c, corresponded with literature, where lower levels were detected on negatively charged surfaces (i.e. mercapto undecanoic acid self-assembled monolayer), and higher levels of more hydrophobic surfaces (i.e. 11-amino undecane thiol self-assembled monolayer). Human plasma fibrinogen was observed to favour hydrophilic over hydrophobic self-assembled monolayer surfaces, which was in accordance with literature. Application of the proposed protein detection method for biocompatibility analysis of target therapeutic molecules, namely metallophthalocyanines and acid functionalised multi-walled carbon nanotubes, demonstrated a dependence on modified-surface film characteristics, such as surface charge and topography with regards to human serum albumin and human plasma fibrinogen analysis representing new insights into their potential biomolecular interactions The highest levels of detected human serum albumin and complement C3c were detected on the GePcSmix-modified surfaces. AlPcSmix-modified surfaces analysis suggested the highest levels of human plasma fibrinogen. Two methods of acid functionalisation were employed, using both nitric and sulphuric acid, and pure nitric acid. A general increase in detected human serum albumin, corresponding with an increase in functionalisation time, was observed. Complement C3c detection suggested an increase in deposited complement C3c, with increasing functionalisation time, when assessing nitric acid functionalised multi-walled carbon nanotubes, and a decrease, with increasing functionalisation time, when assessing nitric and sulphuric acid functionalised multi-walled carbon nanotubes. Analysis of human plasma fibrinogen was inconclusive, as were cytotoxicity experiments utilising MCF-7 cells in the presence of metallophthalocyanine complexes, raising simultaneously important considerations for their application and study. In the first such detailed examination of its kind it was concluded that the proposed method of protein detection, using QCM-D, allows for the rudimentary but rapid means of analysis of select protein corona deposited on particulate biomedical surfaces.
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- Date Issued: 2011
Cross-border tourism planning and development: the case of the Lake Gariep Initiative
- Authors: Crozier, Marguerite Nicole
- Date: 2011
- Subjects: Tourism -- South Africa -- Gariep Dam -- Case studies , Gariep Dam (South Africa) -- Tourism -- Case studies , Central-local government relations -- South Africa -- Gariep Dam , Globalization -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9034 , http://hdl.handle.net/10948/1668 , Tourism -- South Africa -- Gariep Dam -- Case studies , Gariep Dam (South Africa) -- Tourism -- Case studies , Central-local government relations -- South Africa -- Gariep Dam , Globalization -- Economic aspects -- South Africa
- Description: The concept of cross-border tourism planning and cooperation is investigated in reference to the Lake !Gariep Initiative. The field of cross-border economic planning and integration is an area of increasing interest in regional development studies. The Lake Gariep Initiative is an initiative to promote cross-border planning and development around nature conservation, water resource management, economic development, poverty alleviation and tourism in the three municipalities that surround the Gariep Dam. The Gariep Dam, which is largest dam in South Africa, is surrounded by three provinces. The region is also economically and politically marginalised as it has a small, dispersed population and a marginal contribution to the broader regional economy. Under these circumstances the coordination of resources between municipalities to develop and promote the region has been identified as a key success factor for the region. The Lake Gariep Initiative although strongly supported locally has over ten years failed to be institutionalised. This study examines the Lake Gariep Initiative in terms of the origins of the concept and the key challenges that have been faced in establishing a cross-border, development entity. Findings are based on an assessment of documents on the formation of the LGI, interviews with stakeholders involved in the process and an assessment of critical success factors in reference to national and international case studies. This study provides a review of the key challenges, benefits and critical success factors for cross-border tourism development in relation to the Lake !Gariep Initiative.
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- Date Issued: 2011
Textual representations of migrants and the process of migration in selected South African media a combined critical discourse analysis and corpus linguistics study
- Authors: Crymble, Leigh
- Date: 2011
- Subjects: Immigrants in mass media -- South Africa Mass media and foreign workers -- South Africa Refugees -- Press coverage -- South Africa Xenophobia in mass media -- South Africa Critical discourse analysis Corpora (Linguistics) Sunday Times (Johannesburg, South Africa) City Press (Johannesburg, South Africa) Mail & Guardian
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2342 , http://hdl.handle.net/10962/d1002624
- Description: South Africa has long been associated with racial and ethnic issues surrounding prejudice and discrimination and despite a move post-1994 to a democratic ‘rainbow nation’ society, the country has remained plagued by unequal power relations. One such instance of inequality relates to the marginalisation of migrants which has been realised through xenophobic attitudes and actions, most notably the violence that swept across the country in 2008. Several reasons have been suggested in an attempt to explain the cause of the violence, including claims that migrants are taking ‘our jobs and our women’, migrants are ‘illegal and criminal’ and bringing ‘disease and contamination’ with them from their countries of origin. Although widely accepted that many, if not all, of these beliefs are based on ignorance and hearsay, these extensive generalisations shape and reinforce prejudiced ideologies about migrant communities. It is thus only when confronted with evidence that challenges this dominant discourse, that South Africans are able to reconsider their views. Williams (2008) suggests that for many South Africans, Africa continues to be the ‘dark continent’ that is seen as an ominous, threatening force of which they have very little knowledge. For this reason, anti-immigrant sentiment in a South African context has traditionally been directed at African foreigners. In this study I examine the ways in which African migrants and migrant communities, as well as the overall processes of migration, are depicted by selected South African print media: City Press, Mail & Guardian and Sunday Times. Using a combined Corpus Linguistics and Critical Discourse Analysis approach, I investigate the following questions: How are migrants and the process of migration into South Africa represented by these established newspapers between 2006 and 2010? Are there any differences or similarities between these representations? In particular, what ideologies regarding migrants and migrant communities underlie these representations? My analysis focuses on the landscape of public discourse about migration with an exploration of the rise and fall of the terminologies used to categorise migrants and the social implications of these classifications. Additionally, I analyse the expansive occurrences of negative representations of migrants, particularly through the use of ‘othering’ pronouns ‘us’ versus ‘them’ and through the use of metaphorical language which largely depicts these individuals as en masse natural disasters. I conclude that these discursive elements play a crucial role in contributing to an overall xenophobic rhetoric. Despite subtle differences between the three newspapers which can be accounted for based on their political persuasions and agendas, it is surprising to note how aligned these publications are with regard to their portrayal of migrants. With a few exceptions, this representation positions these individuals as powerless and disenfranchised and maintains the status quo view of migrants as burdens on the South African economy and resources. Overall, the newspaper articles contribute to mainstream dominant discourse on migrants and migration with the underlying ideology that migrants are responsible for the hardships suffered by South African citizens. Thus, this study contributes significantly to existing bodies of research detailing discourse on migrants and emphasises the intrinsic links between language, ideology and society.
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- Date Issued: 2011
The photophysical properties of low symmetry phthalocyanines in conjunction with quantum dots
- Authors: D'Souza, Sarah
- Date: 2011
- Subjects: Phthalocyanines , Photochemistry , Zinc , Quantum dots , Spectrum analysis , Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4331 , http://hdl.handle.net/10962/d1004992 , Phthalocyanines , Photochemistry , Zinc , Quantum dots , Spectrum analysis , Nanoparticles
- Description: he synthesis, extensive spectroscopic characterization and photophysical studies of low symmetry zinc phthalocyanine have been conducted. Comparisons have been made taking into consideration the influence of the solvent properties as well as substituent type and position. Photosensitizing properties of the zinc phthalocyanine derivatives in the presence of thiol capped CdTe quantum dots (QDs) were compared. The QDs were used as energy transfer donors and to facilitate with energy transfer through Förster resonance energy transfer (FRET) from the QDs to the MPcs. The linkage of unsymmetrically substituted 4-monoaminophenoxy zinc phthalocyanine (ZnAPPc) to CdTe quantum dots capped with mercaptopropionic acid (MPA), L-cysteine (L-cys) or thioglycolic acid (TGA) has been achieved using the coupling agents ethyl-N3 dimethylaminopropyl)carbodiimide (EDC) and N-hydroxy succinimide (NHS), which facilitate formation of an amide bond to form the QD-ZnAPPc-linked complex. The formation of the amide bond was confirmed using UV-Vis, Raman and IR spectroscopies, as well as AFM (atomic force microscopy). Förster resonance energy transfer (FRET) resulted in stimulated emission of ZnAPPc in both the linked (QDZnAPPc-linked) and mixed (QD:ZnAPPc-mixed) conjugates for MPA only. The linked L-cys and TGA complexes (QD-ZnAPPc-linked) gave the largest FRET efficiencies hence showing the advantages of covalent linking. Fluorescence quantum yields of QDs were decreased in QD:ZnAPPc-mixed and QD:ZnAPPc-linked. High triplet state quantum yields were obtained for the linked QD-phthalocyanine derivatives (ZnAPPc)and monoaminozinc phthalocyanine (ZnAPc) compared to when ZnAPPc and ZnAPc were mixed with MPA QDs without a chemical bond.
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- Date Issued: 2011