4,586 research outputs found

    The Shame of the Nation

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    Collaboration for innovation in services

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    The research was motivated by the importance of inter-firm collaboration within service innovation. Inter-firm collaboration covers a broad range of organizational combinations of various size and motivations in various levels of formal agreements. The book chapter will explore the choice of different partners and knowledge sources for enabling co-operative innovation activities following the approach of loosely-coupled and institutional networks. The empirical results show different collaborative behavior within different service industries. --innovation management,service innovation,collaboration

    Finite element error analysis of wave equations with dynamic boundary conditions: L2L^2 estimates

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    L2L^2 norm error estimates of semi- and full discretisations, using bulk--surface finite elements and Runge--Kutta methods, of wave equations with dynamic boundary conditions are studied. The analysis resides on an abstract formulation and error estimates, via energy techniques, within this abstract setting. Four prototypical linear wave equations with dynamic boundary conditions are analysed which fit into the abstract framework. For problems with velocity terms, or with acoustic boundary conditions we prove surprising results: for such problems the spatial convergence order is shown to be less than two. These can also be observed in the presented numerical experiments

    Direct Step & Shoot: a New Module for Prostate Cancer IMRT

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    Aims & Objectives The aim of this treatment planning study is to compare the techniques of 3D conformal radiotherapy (3DCRT) and IMRT to determine the feasible advantages for prostate cancer patientsof using a new direct step & shoot (DSS) IMRT module. For the optimisation of the IMRT, Nucletron offers as a part of the optimising process their IM-optimisation software or their new module DSS. The earlier IM-optimisation software searches first for the ideal fluence for each beam, and this is then followed by the segmentation. The new DSS module integrates the segmentation into the optimisation process. Materials & Methods Between March 2006 and November 2006, four patients with a mean age of 71 years were enrolled for primary EBRT for localised prostate cancer. Three of these patients received antiandrogen therapy either before or during radiotherapy. All four patients had 3D CT treatment planning with a slice thickness of 5 mm and with immobilisation in a vacuum mattress (BlueBAG BodyFIX, Medical Intelligence). As an initial step, it was planned (using Oncentra MasterPlan) to deliver 60 Gy to the planning target volume (PTV), calculated using data for a Siemens Primus linear accelerator (15 MV photons, with multileaf collimator leaf width of 1cm at the isocentre). The preselected gantry angles were 25, 90, 120, 240, 270 and 335 degrees. The rectal volume and urinary bladder were delineated as organs at risk (OARs). Additional structures were also contoured in order to help (we term them ‘Help Contours’) avoid hot spots in normal tissues surrounding the PTV to a distance of 1cm. The dose-volume objectives were defined by two schemes. After optimisation the plans were re-normalised to the average of PTV, giving 30 fractions with a fractional dose of 2 Gy. The 3DCRT plan used identical gantry angles with the beams weighted by experience. Results Both IMRT optimisation schemes reduced the doses received by the OARs when compared to the 3DCRT plan. Using the Nucletron IM-optimisation software the first weighting scheme of the objectives resulted in satisfactory dose-volume histograms (DVHs) for the OARs, and an obviously 'softened' DVH for the PTV (when compared to the 3DCRT plan). The DSS optimisation produced a steeper DVH for the PTV, but worse results for the OARs when compared to the IM-optimisation. Scheme 2 improved the DVHs for the OARs using the DSS process, to about the same level as the IM-optimisation with scheme 1, the PTV DVH staying nearly unchanged. The IM-optimisation produced the worst DVH for the PTV of the five different plans we considered. In Figure 1 the DVHs are shown of a characteristic 3DCRT plan, the IM plan (Scheme 1) and the DSS plan (Scheme 2). Table 1 presents the mean values, averaged over the four patients, for the PTV and for the two OARs. Conclusions In every case the DSS optimisation resulted in a steeper DVH for the PTV than found using the IM process. The DVHs for the OARs are worse with scheme 1 but improve to about the same level with scheme 2. The patients benefit from IMRT by reduced doses to the OARs, keeping a very steep DVH for the PTV with the DSS optimisation. The user should note that weighting schemes based on the experience with IM-optimisation are not retained for the new DSS optimiation without control

    The proteostasis network and its decline in ageing

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    Ageing is a major risk factor for the development of many diseases, prominently including neurodegenerative disorders such as Alzheimer disease and Parkinson disease. A hallmark of many age-related diseases is the dysfunction in protein homeostasis (proteostasis), leading to the accumulation of protein aggregates. In healthy cells, a complex proteostasis network, comprising molecular chaperones and proteolytic machineries and their regulators, operates to ensure the maintenance of proteostasis. These factors coordinate protein synthesis with polypeptide folding, the conservation of protein conformation and protein degradation. However, sustaining proteome balance is a challenging task in the face of various external and endogenous stresses that accumulate during ageing. These stresses lead to the decline of proteostasis network capacity and proteome integrity. The resulting accumulation of misfolded and aggregated proteins affects, in particular, postmitotic cell types such as neurons, manifesting in disease. Recent analyses of proteome-wide changes that occur during ageing inform strategies to improve proteostasis. The possibilities of pharmacological augmentation of the capacity of proteostasis networks hold great promise for delaying the onset of age-related pathologies associated with proteome deterioration and for extending healthspan

    Activity in the Visual Cortex is Modulated by Top-Down Attention Locked to Reaction Time

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    We studied the correlation between perception and hemodynamic activity in the visual cortex in a change detection task. Whenever the observer perceived the location of a change, rightly or wrongly, the blood oxygenation level-dependent signal increased in the primary visual cortex and the nearby extrastriate areas above the baseline activity caused by the visual stimulation. This non-sensory-evoked activity was localized and corresponded to the perceived location of the change. When a change was missed, or when observers attended to a different task, the change failed to evoke such a response. The latency of the nonsensory component increased linearly with subjects' reaction time, with a slope of one, and its amplitude was independent of contrast. Control experiments are compatible with the hypothesis that the nonsensory hemodynamic signal is mediated by top-down spatial attention, linked to (but separate from) awareness of the change
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