820 research outputs found

    Het gewicht van het gewicht

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    Inkopende organisaties zijn zich soms onvoldoende bewust van de rol van gewichten in de beoordelingsprocedure. Geen wonder dat de uitkomsten van de beoordeling dan soms ook verrassend zijn

    Properties of rainfall in a tropical volcanic island deduced from UHF wind profiler measurements

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    The microphysical properties of rainfall at the island of Réunion are analysed and quantified according to one year of wind profiler observations collected at Saint-Denis international airport. The statistical analysis clearly shows important differences in rain vertical profiles as a function of the seasons. During the dry season, the vertical structure of precipitation is driven by trade wind and boundary-layer inversions, both of which limit the vertical extension of the clouds. The rain rate is lower than 2.5 mm h<sup>−1</sup> throughout the lower part of the troposphere (about 2 km) and decreases in the higher altitudes. During the moist season, the average rain rate is around 5 mm h<sup>−1</sup> and nearly uniform from the ground up to 4 km. <br><br> The dynamical and microphysical properties (including drop size distributions) of four distinct rainfall events are also investigated through the analysis of four case studies representative of the variety of rain events occurring on Réunion: summer deep convection, northerly-to-northeasterly flow atmospheric pattern, cold front and winter depression embedded in trade winds. Radar-derived rain parameters are in good agreement with those obtained from collocated rain gauge observations in all cases, which demonstrates that accurate qualitative and quantitative analysis can be inferred from wind profiler data. Fluxes of kinetic energy are also estimated from wind profiler observations in order to evaluate the impact of rainfall on soil erosion. Results show that horizontal kinetic energy fluxes are systematically one order of magnitude higher than vertical kinetic energy fluxes. A simple relationship between the reflectivity factor and vertical kinetic energy fluxes is proposed based on the results of the four case studies

    What is the Machine Learning?

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    Applications of machine learning tools to problems of physical interest are often criticized for producing sensitivity at the expense of transparency. To address this concern, we explore a data planing procedure for identifying combinations of variables -- aided by physical intuition -- that can discriminate signal from background. Weights are introduced to smooth away the features in a given variable(s). New networks are then trained on this modified data. Observed decreases in sensitivity diagnose the variable's discriminating power. Planing also allows the investigation of the linear versus non-linear nature of the boundaries between signal and background. We demonstrate the efficacy of this approach using a toy example, followed by an application to an idealized heavy resonance scenario at the Large Hadron Collider. By unpacking the information being utilized by these algorithms, this method puts in context what it means for a machine to learn.Comment: 6 pages, 3 figures. Version published in PRD, discussion adde

    Ethical issues arising from the requirement to sign a consent form in palliative care.

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    International audienceFrench healthcare networks aim to help healthcare workers to take care of patients by improving cooperation, coordination and the continuity of care. When applied to palliative care in the home, they facilitate overall care including medical, social and psychological aspects. French legislation in 2002 required that an information document explaining the functioning of the network should be given to patients when they enter a healthcare network. The law requires that this document be signed. Ethical issues arise from this legislation with regard to the validity of the signature of dying patients. Signature of the consent form by a guardian or trustee, a designated person--the Person of Trust--transforms the doctor-patient relationship into a triangular doctor-patient-third-party relationship
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