Les risques en images

Les risques en imagesEntre juin 2019 et mai 2020, le Centre de recherche sur les Risques et les Crises (CRC) de l’École Nationale Supérieure des Mines de Paris publia sur son site internet une série intitulée « Les risques en images ». L’objectif de ce projet pluridisciplinaire et collaboratif était de décrypter, chaque mois, une peinture, une affiche, une photographie, une gravure, un graphique ou un modèle représentant un risque, un accident ou une situation de crise. La direction éditoriale des Risques en images fut assurée par Aurélien Portelli, chargé de recherche au CRC. Le document suivant regroupe les douze numéros de la série

A new generation zero-dimensional physics-based model for proton-exchange membrane fuel cells

International audienceFinding a good trade-off between accuracy and complexity, computational cost of physics-based models of proton-exchange membrane fuel cells is not an easy task. Relatively simple zero-dimensional (0D) models allow for fast simulation and integration in more complex system-level models. On the downside, sensitivity to varying operating conditions is not necessarily well captured, especially for strong current densities where liquid water, gas transport resistance and temperature gradients may be present. Therefore, the current trend in the literature is towards more complex models going from 1D+1D to 3D models, where full transport equations are solved, at the expense of a high computational cost and an impressive list of required input parameters (not always readily available) [1]. Except for a few works, such as the ones from Ritzberger et al. [2] or Schröder et al. [3], not much effort has been addressed at developing performant 0D models since the foundation works of early 2000s. Here we propose a new generation physics-based PEM fuel cell 0D model which consider recent insights gained from experimental work on oxygen transport resistance [4,5] and catalyst layer proton resistance [6], ionomer thin-film properties [7] and platinum oxidation [8]. An analytical solution for water transport in the PFSA membrane developed by Ferrara et al. [9] is also included. A first validation of the model against experimental data and model results from Gass et al. [10] and Goshtasbi et al. [11] is presented, which shows that the model captures well the impact of varying operating conditions

Nanopore Sequencing as a Cutting-Edge Technology for Medulloblastoma Classification

International audienceBackground: Medulloblastoma (MB) is one of the most prevalent embryonal malignant brain tumors. Current classification organizes these tumors into four molecular subgroups (WNT, SHH, Group 3, and Group 4 MB). Recently, a comprehensive classification has been established, identifying numerous subtypes, some of which exhibit a poor prognosis. It is critical to establish effective subtyping methods for accurate diagnosis and patient's management that strikes a delicate balance between improving outcomes and minimizing the risk of comorbidities.Methods: We evaluated the ability of Nanopore sequencing to provide clinically relevant methylation and copy number profiles of MB. Nanopore sequencing was applied to an EPIC cohort of 44 frozen MB, benchmarked against the gold standard EPIC array, and further evaluated on an integrated diagnosis cohort of 116 MB.Results: Most MB of both cohorts (42/44; 95.5% and 106/116; 91.4% respectively) were accurately subgrouped by Nanopore sequencing. Employing Flongle flow cells for 18 MB allowed a more rapid and cost-effective analysis, with 94.4% (17/18) being correctly classified. Nanopore sequencing enabled us to accurately subtype 28/30 (93.3%) MB.Conclusion: This study, conducted on the largest cohort of MB analyzed with Nanopore sequencing to date, establishes the proof of concept that this modern and innovative technology is well-suited for MB classification. Nanopore sequencing demonstrates a robust capacity for precise subtyping of MB, a critical advancement that holds significant potential for enhancing patient stratification in future clinical trials. Its ability to deliver quick and cost-effective results firmly establishes it as a game-changer in the field of MB classification

Thermal-solutal convection-induced low-angle grain boundaries in single-crystal nickel-based superalloy solidification

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Stochastic Coefficient of Variation: Assessing the Variability and Forecastability of Solar Irradiance

International audienceThis work presents a robust framework for quantifying solar irradiance variability and forecastability through the Stochastic Coefficient of Variation () and the Forecastability (). Traditional metrics, such as the standard deviation, fail to isolate stochastic fluctuations from deterministic trends in solar irradiance. By considering clear-sky irradiance as a dynamic upper bound of measurement, provides a normalized, dimensionless measure of variability that theoretically ranges from 0 to 1. extends by integrating temporal dependencies via maximum autocorrelation, thus linking with . The proposed methodology is validated using synthetic cyclostationary time series and experimental data from 68 meteorological stations (in Spain). Our comparative analyses demonstrate that and proficiently encapsulate multi-scale fluctuations, while addressing significant limitations inherent in traditional metrics. This comprehensive framework enables a refined quantification of solar forecast uncertainty, supporting improved decision-making in flexibility procurement and operational strategies. By assessing variability and forecastability across multiple time scales, it enhances real-time monitoring capabilities and informs adaptive energy management approaches, such as dynamic outage management and risk-adjusted capacity allocatio

On the Assessment of Hourly Means of Solar Irradiance at Ground Level in Clear-Sky Conditions by the ERA5, JRA-3Q, and MERRA-2 Reanalyses

International audienceMeteorological reanalyses are one of the means to assess the solar irradiance reaching the ground. This paper deals with estimates of the hourly means of irradiance in clear-sky conditions provided by the ERA5, JRA-3Q, and MERRA-2 reanalyses. They are compared to coincident ground-based measurements from 28 BSRN stations located worldwide, selected by a new algorithm for detecting cloud-free instants. Although ERA5 most often underestimates measurements, it is quite reliable over time because it captures the temporal variability of measurements well and provides a constant level of uncertainty. JRA-3Q offers a complex pattern with negative and positive biases depending on station and season. It captures well the temporal variability but, as a whole, is not reliable over time. None of the three reanalyses is reliable in space. Because of its use of the mean solar time instead of the true solar time, MERRA-2 suffers many drawbacks over intraday scales. Its statistical indicators exhibit marked patterns depending on the season and station. Its assimilation of aerosol properties offers advantages when compared to the climatologies used in ERA5 and JRA-3Q. This work exposes the strengths and weaknesses of each reanalysis in clear-sky conditions and formulates suggestions to providers for further improvements.</div

La série de science-fiction au service de l’organisation. Le cas du programme Red Team Défense du ministère des Armées français

Chapitre 14Peut-on faire de la recherche scientifique sur les liens entre séries télévisées et management ? C'est le pari de cet ouvrage, adossé à la première édition (« saison », forcément !) du colloque Management en Séries qui s'est déroulé à l'université Gustave Eiffel en mars 2023.Il se déploie dans trois directions complémentaires : en examinant comment les séries télévisées peuvent nous aider à déconstruire les pratiques de management, en développant des méthodes pédagogiques visant à stimuler la réflexivité des étudiants et en proposant des réflexions sur les liens entre réalités du management et fictions télévisuellesVous qui tenez cet ouvrage entre vos mains, peut-être est-ce parce que vous êtes vous-même un gros consommateur de séries TV... voire un "binge-watcher" ? Rassurez-vous : en lisant ce livre, vous n'en serez que plus décomplexé, car son ambition est de montrer en quoi les séries TV sont plus que de simples fictions ou divertissements, qu'elles nous parlent de nos vies professionnelles et en particulier du management contemporain et de pratiques... que la recherche en sciences sociales peut saisir et inviter à dépasser. "Peut-on faire de la recherche scientifique sur les liens entre séries TV et management ? " Tenter de répondre à cette question, c'est le pari de cet ouvrage, adossé à la première édition ("saison", forcément ! ) du colloque Management en séries qui s'est déroulé à l'université Gustave Eiffel en mars 2023. Les contributions des auteurs vous proposeront d'examiner comment les séries TV peuvent nous aider à déconstruire les pratiques managériales, ou encore comment mobiliser ces séries pour mieux enseigner le management et stimuler la réflexivité des étudiants.Enfin, l'ouvrage propose de mettre en miroir la réalité du management avec celle représentée dans les fictions sérielles. En somme, déculpabilisez-vous de votre consommation de séries, tout en lisant un livre : LEGENDARY

"Interroger la transformation des pratiques financières pour comprendre le pouvoir transformatif de la finance responsable. L’étude de cas de la méthode de mesure d’alignement de MIROVA"

International audienceFaced with a form of crisis in sustainable finance, we argue in this research for the need to question the effects of the instrumentation of E&amp;S performance, within the responsible investment process. We propose to study an emerging form of instrumentation: the alignment method. Finally, we demonstrate its ability, by acting at the portfolio level and not just at the level of the investment universe, to generate and above all manage the various adjustments made by assets's managers.Résumé : Face à une crise de la finance durable, nous argumentons dans cette recherche de la nécessité d’interroger les effets de l’instrumentation de la performance E&amp;S au sein du processus d’investissement responsable. Nous proposons d’étudier une forme d’instrumentation émergente : la méthode d’alignement. Nous démontrons enfin sa capacité, en agissant au niveau du portefeuille et non au seul niveau de l’univers d’investissement, à générer et surtout à gérer les divers ajustements opérés par les gérants dans la reconfigurations de leurs portefeuilles