339,373 research outputs found

    Failure characteristics of all polyethylene cemented glenoid implants in total shoulder arthroplasty

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    Total shoulder arthroplasty (TSA) still suffers today from mid-term and long-term complications such as glenoid implant loosening, wear, humeral head subluxation/dislocation and implant fracture. Unlike the hip and knee joint replacements, the artificial shoulder joint has yet to offer a long-term satisfactory solution to shoulder replacement. With loosening being the number one reason for TSA revision, investigating methods of monitoring the glenoid implant loosening and investigate the effects of various design parameters on the loosening behaviour of the glenoid fixation is necessary to explore the problem. Several studies were carried out using in-vitro cyclic testing and FEA to; investigate failure progression and its correlation to quantitative measures in a 2D study (n = 60), investigating key glenoid design features in a 2D (n = 60) and 3D study (n = 20), investigating the validity of using bone substitute foam for studying glenoid fixation in a cadaveric study and investigating any correlation between failure and CT or in-vitro quantitative measures (n = 10). Visible failure was observed, for the first time, correlating to inferior rim displacement and vertical head displacement measures. CT failure was detected in 70% of specimens before visible failure was observed. Out of the design pairs tested; smooth-back/rough-back (range of roughnesses), peg/keel, curved-back/flat-back and conforming/non-conforming, roughening the back-surface to 3.4 μm or more improved fixation performance (p < 0.05). Roughening the back-surface changed the mode of failure from implant/cement failure inferiorly due to tensile/shear stresses, to cement/bone failure superiorly due to compressive/shear loading. Differences in the other design pairs were marked showing peg to perform better than keel, conforming over non-conforming and no difference in curved-back over flat-back, although these differences are marginal. Improvements in the standard testing method have also been suggested

    Participatory knowledge mobilisation: an emerging model for international translational research in education

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    Research alone does not inform practice, rather a process of knowledge translation is required to enable research findings to become meaningful for practitioners in their contextual settings. However, the translational process needs to be an iterative cycle so that the practice itself can be reflected upon and thereby inform the ongoing research agenda. This paper presents the initial findings of a study into an international, participatory model of knowledge mobilization in the context of translational research in the field of education. Using a mixed methods approach, the study draws upon data collected from the Education Futures Collaboration (EFC), an educational charity, which has developed an international knowledge mobilization strategy. Through the innovative use of technologies this initiative improves the link between research and practice by finding new and practical ways to improve the knowledge base for practitioners. The EFC has developed two work strands within the international knowledge mobilization strategy, which utilise two complementary digital platforms. The first is the online MESHGuides (Mapping Educational Specialist knowHow), a collaborative tool for connecting educators with visual summaries of educational research from which practice can be developed. The second is the online Education Communities of Practice network, which is used to support international partnerships for collaboration between researchers and practitioners. Findings indicate that utilising web 2.0 tools to develop translational research through MESHGuides is significantly groundbreaking in its vision and scope with respect to practitioners accessing and building the knowledge base of the teaching profession internationally and strengthening the link between researchers and practitioners, thereby increasing the impact of research in education

    Harnessing Technology in Schools Survey 2007: technical report

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    This technical report provides a detailed review of the methods used and the data gathered for this survey. The report also provides copies of the research instruments used in this survey

    Investigations into stability in the fig/ fig-wasp mutualism

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    Fig trees (Ficus, Moraceae) and their pollinating wasps (Chalcidoidea, Agaonidae) are involved in an obligate mutualism where each partner relies on the other in order to reproduce: the pollinating fig wasps are a fig tree’s only pollen disperser whilst the fig trees provide the wasps with places in which to lay their eggs. Mutualistic interactions are, however, ultimately genetically selfish and as such, are often rife with conflict. Fig trees are either monoecious, where wasps and seeds develop together within fig fruit (syconia), or dioecious, where wasps and seeds develop separately. In interactions between monoecious fig trees and their pollinating wasps, there are conflicts of interest over the relative allocation of fig flowers to wasp and seed development. Although fig trees reap the rewards associated with wasp and seed production (through pollen and seed dispersal respectively), pollinators only benefit directly from flowers that nurture the development of wasp larvae, and increase their fitness by attempting to oviposit in as many ovules as possible. If successful, this oviposition strategy would eventually destroy the mutualism; however, the interaction has lasted for over 60 million years suggesting that mechanisms must be in place to limit wasp oviposition. This thesis addresses a number of factors to elucidate how stability may be achieved in monoecious fig systems. Possible mechanisms include: 1) a parasitoidcentred short ovipositor hypothesis in Ficus rubiginosa, which suggests that a subset of flowers are out of reach to parasitoid ovipositors making these ovules the preferred choice for ovipositing pollinators and allowing seeds to develop in less preferred ovules; 2) the presence of third-party mutualists such as non-pollinating fig wasps (F. burkei) and patrolling green tree ants on the fig surface (F. racemosa) that limit pollinator and parasitoid oviposition respectively; and 3) selection on fig morphology which constrains the size (and therefore fecundity) of the associated pollinators. I discuss the lack of evidence for a single unifying theory for mutualism stability and suggest that a more likely scenario is the presence of separate, and perhaps multiple, stabilising strategies in different fig/ fig-wasp partnerships
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