Heliocentric distance dependencies of the C2 lifetime and C2 parent production rate in comet P/Brorsen-Metcalf (1989o)

Comet P/Brorsen-Metcalf (1989o) has been extensively observed in the visible and in the ultraviolet during its latest apparition of summer 1989. In this paper we report a preliminary determination of the C2 production rates and lifetimes and we compare those rates to the H2O production rates obtained from UV data

Débat scolaire : les enjeux anthropologiques d’une didactisation

L’apparition du débat dans l’humanité a des enjeux anthropologiques forts : politique (partage démocratique du pouvoir), épistémologique (démarche socialisée de co - construction du savoir), éthique (respect d’autrui et morale de la pensée). Mis à l’ordre du jour de notre système éducatif, c’est à partir de ces enjeux qu’il doit être didactisé, comme objectif et moyen d’apprentissage : apprendre la discussion, apprendre par la discussion, apprendre à vivre ensemble par la discussion.The apparition of the debate in human history contains some strong anthropological stakes : political stakes (democratic division of power); epistemological stakes (socialized procedure to built a common knowledge); ethical stakes (respect of others and caring thinking). Put on the educational agenda, it must be “didactised”, as objective as well as means of learning : learning to discuss, learning through discussion, learning to live together through discussion

La construction identitaire de l’élève par le questionnement et la discussion à visée philosophique

Pour aborder cette question, qui pour nous fait référence à la pratique innovante de la Discussion à Visée Philosophique (DVP) à l’école primaire, nous clarifierons dans un premier temps la notion d’identité, par une approche non psychologique ou sociologique, mais référée à des auteurs philosophiques ; puis celle de construction identitaire, pensée en relation avec les notions de subjectivité, de temporalité, de langage et de liberté. Dans un second temps, nous montrerons comment la pratique de la DVP en classe favorise cette construction de l’enfant en tant que sujet pensant : en premier lieu, à travers un usage réflexif, et non fonctionnel, de la langue ; en second lieu par la mise en oeuvre d’un certain nombre de démarches de pensée à visée philosophique ; enfin par un processus démocratiquement socialisateur.To address this issue which in our view refers to the emerging/innovating practice of dialogical philosophical discussion in elementary school, we will first clarify the notion of identity through an approach which is neither psychological nor sociological but in reference to philosophical authors ; and then the notion of the construction of identity viewed  in relation to the notions of subjectivity , temporality, language and liberty. Secondly, we will show how dialogic discussion in class fosters the child’s construction as a critical thinking subject : first, through a reflective but not functional use of language ; second, through the implementation of various dialogical discussions and finally through a democratic process facilitating socialization

La construction identitaire de l’élève par le questionnement et la discussion à visée philosophique

Pour aborder cette question, qui pour nous fait référence à la pratique innovante de la Discussion à Visée Philosophique (DVP) à l’école primaire, nous clarifierons dans un premier temps la notion d’identité, par une approche non psychologique ou sociologique, mais référée à des auteurs philosophiques ; puis celle de construction identitaire, pensée en relation avec les notions de subjectivité, de temporalité, de langage et de liberté. Dans un second temps, nous montrerons comment la pratique de la DVP en classe favorise cette construction de l’enfant en tant que sujet pensant : en premier lieu, à travers un usage réflexif, et non fonctionnel, de la langue ; en second lieu par la mise en oeuvre d’un certain nombre de démarches de pensée à visée philosophique ; enfin par un processus démocratiquement socialisateur.To address this issue which in our view refers to the emerging/innovating practice of dialogical philosophical discussion in elementary school, we will first clarify the notion of identity through an approach which is neither psychological nor sociological but in reference to philosophical authors ; and then the notion of the construction of identity viewed  in relation to the notions of subjectivity , temporality, language and liberty. Secondly, we will show how dialogic discussion in class fosters the child’s construction as a critical thinking subject : first, through a reflective but not functional use of language ; second, through the implementation of various dialogical discussions and finally through a democratic process facilitating socialization

Édito - Vingt ans de Nouvelles Pratiques Philosophiques en France

Pourquoi un tel numéro ? 20 ans depuis le premier café philosophique créé en 1992 par Marc Sautet, Maître de Conférences en philosophie à HEC, au café des Phares, place de la Bastille à Paris… 20 ans de pratiques, c’est-à-dire non de productions théoriques, doctrinales, conceptuelles de philosophes, mais d’activités concrètes dans des cafés, médiathèques, cinémas, théâtres, foyers de jeunes travailleurs, hôpitaux, maisons de retraite, prisons, etc. ; et d’actions pédagogiques et didactiques d..

Primary isolated aortic valve surgery in octogenarians

Objectives: We reviewed our surgery registry, to identify predictive risk factors for operative results, and to analyse the long-term survival outcome in octogenarians operated for primary isolated aortic valve replacement (AVR). Methods: A total of 124 consecutive octogenarians underwent open AVR from January 1990 to December 2005. Combined procedures and redo surgery were excluded. Selected variables were studied as risk factors for hospital mortality and early neurological events. A follow-up (FU; mean FU time: 77 months) was obtained (90% complete), and Kaplan-Meier plots were used to determine survival rates. Results: The mean age was 82±2.2 (range: 80-90 years; 63% females). Of the group, four patients (3%) required urgent procedures, 10 (8%) had a previous myocardial infarction, six (5%) had a previous coronary angioplasty and stenting, 13 patients (10%) suffered from angina and 59 (48%) were in the New York Heart Association (NYHA) class III-IV. We identified 114 (92%) degenerative stenosis, six (5%) post-rheumatic stenosis and four (3%) active endocarditis. The predicted mortality calculated by logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 12.6±5.7%, and the observed hospital mortality was 5.6%. Causes of death included severe cardiac failure (four patients), multi-organ failure (two) and sepsis (one). Complications were transitory neurological events in three patients (2%), short-term haemodialysis in three (2%), atrial fibrillation in 60 (48%) and six patients were re-operated for bleeding. Atrio-ventricular block, myocardial infarction or permanent stroke was not detected. The age at surgery and the postoperative renal failure were predictors for hospital mortality (p value ≪0.05), whereas we did not find predictors for neurological events. The mean FU time was 77 months (6.5 years) and the mean age of surviving patients was 87±4 years (81-95 years). The actuarial survival estimates at 5 and 10 years were 88% and 50%, respectively. Conclusions: Our experience shows good short-term results after primary isolated standard AVR in patients more than 80 years of age. The FU suggests that aortic valve surgery in octogenarians guarantees satisfactory long-term survival rates and a good quality of life, free from cardiac re-operations. In the era of catheter-based aortic valve implantation, open-heart surgery for AVR remains the standard of care for healthy octogenarian

Surgical glues: are they really adhesive?

Objective: The aim of this study is to create a standard test to approve the efficacy of a surgical sealant. An industrial test, the bulge-and-blister test, which is very convenient for measuring adhesion energy, is applied to the surgical field to quantify adhesion of bioadhesives. Methods: Samples were composed of two circular layers of equine pericardium glued by the surgical sealant studied. The sample was fixed to a support with an industrial glue. The support and the bottom layer were perforated in the centre to allow injection of pressurised water. Water was progressively introduced through the hole in the support and the bottom layer to create a blister with constant radius, increasing height and internal pressure during this first step. At a critical pressure, delamination started, the radius and height of the blister increased and the pressure decreased. At this point, the adhesion energy could be determined. The experimental parameters were measured with a pressure sensor and an optical profilometry device for deflection. Results: Adhesion testing was carried out in eight paired equine pericardium samples bonded with a Dermabond® cyanoacrylate glue. The average value of the practical adhesion energy is 2.3Jm−2 with a standard deviation of 1.5Jm−2. Conclusion: Application of the bulge-and-blister test to the surgical field was achieved and allowed a quantification of adhesion of a surgical glue. Such information is essential to compare the different surgical glues presently available. The study of the impact of bonding conditions such as pressure, hygrometry or setting conditions will provide a better understanding of the characteristics of adhesion in the surgical fiel

Parameterization Effects in the analysis of AMI Sunyaev-Zel'dovich Observations

Most Sunyaev--Zel'dovich (SZ) and X-ray analyses of galaxy clusters try to constrain the cluster total mass and/or gas mass using parameterised models and assumptions of spherical symmetry and hydrostatic equilibrium. By numerically exploring the probability distributions of the cluster parameters given the simulated interferometric SZ data in the context of Bayesian methods, and assuming a beta-model for the electron number density we investigate the capability of this model and analysis to return the simulated cluster input quantities via three rameterisations. In parameterisation I we assume that the T is an input parameter. We find that parameterisation I can hardly constrain the cluster parameters. We then investigate parameterisations II and III in which fg(r200) replaces temperature as a main variable. In parameterisation II we relate M_T(r200) and T assuming hydrostatic equilibrium. We find that parameterisation II can constrain the cluster physical parameters but the temperature estimate is biased low. In parameterisation III, the virial theorem replaces the hydrostatic equilibrium assumption. We find that parameterisation III results in unbiased estimates of the cluster properties. We generate a second simulated cluster using a generalised NFW (GNFW) pressure profile and analyse it with an entropy based model to take into account the temperature gradient in our analysis and improve the cluster gas density distribution. This model also constrains the cluster physical parameters and the results show a radial decline in the gas temperature as expected. The mean cluster total mass estimates are also within 1 sigma from the simulated cluster true values. However, we find that for at least interferometric SZ analysis in practice at the present time, there is no differences in the AMI visibilities between the two models. This may of course change as the instruments improve.Comment: 19 pages, 13 tables, 24 figure

The instrument control unit of the ARIEL payload: design evolution following the unit and payload subsystems SRR (system requirements review)

ARIEL (Atmospheric Remote-sensing InfraRed Large-survey) is a medium-class mission of the European Space Agency, part of the Cosmic Vision program, whose launch is foreseen by early 2029. ARIEL aims to study the composition of exoplanet atmospheres, their formation and evolution. The ARIEL’s target will be a sample of about 1000 planets observed with one or more of the following methods: transit, eclipse and phase-curve spectroscopy, at both visible and infrared wavelengths simultaneously. The scientific payload is composed by a reflective telescope having a 1m-class elliptical primary mirror, built in solid Aluminium, and two focal-plane instruments: FGS and AIRS. FGS (Fine Guidance System)1 has the double purpose, as suggested by its name, of performing photometry (0.50-0.55 µm) and low resolution spectrometry over three bands (from 0.8 to 1.95 µm) and, simultaneously, to provide data to the spacecraft AOCS (Attitude and Orbit Control System) with a cadence of 10 Hz and contributing to reach a 0.02 arcsec pointing accuracy for bright targets. AIRS (ARIEL InfraRed Spectrometer) instrument will perform IR spectrometry in two wavelength ranges: between 1.95 and 3.9 µm (with a spectral resolution R > 100) and between 3.9 and 7.8 µm with a spectral resolution R > 30. This paper provides the status of the ICU (Instrument Control Unit), an electronic box whose purpose is to command and supply power to AIRS (as well as acquire science data from its two channels) and to command and control the TCU (Telescope Control Unit)