Les difficultés pratiques des communautés de pratique.

Nous analysons les difficultés liées à une tentative de "mise en œuvre" de communautés de pratique au sein d'une organisation hiérarchique. Nous nous intéressons plus particulièrement aux enjeux de pouvoir susceptibles de remettre en cause les communautés de pratique comme espaces d'apprentissage interstitiel. La recherche repose sur l'étude de quatre communautés de pratique au sein d'une même entreprise. L'étude est réalisée au moyen d'entretiens semi- directifs. Les résultats montrent les difficultés rencontrées, en particulier en raison du système de management de l'entreprise et de l'enjeu de pouvoir que représentent les communautés de pratique. Sur les quatre cas étudiés, un seul parvient à conserver la caractéristique fondamentale de l'auto-organisation. Dans deux autres cas, le fonctionnement devient hiérarchique et la communauté de pratique se transforme en groupe de travail. Le quatrième cas évolue vers une situation intermédiaire. De manière plus large, c'est la capacité d'une organisation hiérarchique à stimuler sans l'étouffer une forme originellement clandestine qui peut être mise en cause.Communauté de pratique; apprentissage; gestion de la connaissance; pouvoir;

Relative entropy and the stability of shocks and contact discontinuities for systems of conservation laws with non BV perturbations

We develop a theory based on relative entropy to show the uniqueness and L^2 stability (up to a translation) of extremal entropic Rankine-Hugoniot discontinuities for systems of conservation laws (typically 1-shocks, n-shocks, 1-contact discontinuities and n-contact discontinuities of large amplitude) among bounded entropic weak solutions having an additional trace property. The existence of a convex entropy is needed. No BV estimate is needed on the weak solutions considered. The theory holds without smallness condition. The assumptions are quite general. For instance, strict hyperbolicity is not needed globally. For fluid mechanics, the theory handles solutions with vacuum.Comment: 29 page

Spatially Resolved 3 um Spectroscopy of IRAS 22272+5435: Formation and Evolution of Aliphatic Hydrocarbon Dust in Proto-Planetary Nebula

We present medium-resolution 3 um spectroscopy of the carbon-rich proto-planetary nebula IRAS 22272+5435. Spectroscopy with the Subaru Telescope adaptive optics system revealed a spatial variation of hydrocarbon molecules and dust surrounding the star. The ro-vibrational bands of acetylene (C2H2) and hydrogen cyanide (HCN) at 3.0 um are evident in the central star spectra. The molecules are concentrated in the compact region near the center. The 3.3 and 3.4 um emission of aromatic and aliphatic hydrocarbons is detected at 600--1300 AU from the central star. The separation of spatial distribution between gas and dust suggests that the small hydrocarbon molecules are indeed the source of solid material, and that the gas leftover from the grain formation is being observed near the central star. The intensity of aliphatic hydrocarbon emission relative to the aromatic hydrocarbon emission decreases with distance from the central star. The spectral variation is well matched to that of a laboratory analog thermally annealed with different temperatures. We suggest that either the thermal process after the formation of a grain or the variation in the temperature in the dust-forming region over time determines the chemical composition of the hydrocarbon dust around the proto-planetary nebula.Comment: 14 pages, 7 figures, Accepted for publication in the Astrophyical Journa

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

LA TURQUIE, DEUXIEME PATRIE DE PIERRE LOTI

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Tractatus theologicus de providentia Dei [Manuscrito] / dictatus fuit a Rmo. P.M. Jacobo a St. Leger ; scriptusque a Mathia Rodriguez

Signatura: Ms 260142 f.; 21 cmLatínFoliación antiga a tintaEncadernación en pergameoÍndice ó finalManuscrito probablemente procedente do Colexio da Compañía de Xesús de Santiag

Diagnostic de la coqueluche par amplification génique chez l'enfant. Etude cas-temoin rétrospective (2000-2004) de 116 cas

REIMS-BU Santé (514542104) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF