Grand événement - Musique ! La Philharmonie au Collège de France : Composer aujourd'hui
Grand événement - Musique ! La Philharmonie au Collège de FranceCycle de rencontres en partenariat avec la Cité de la musique – Philharmonie de ParisCollège de FranceAnnée 2025-2026Composer aujourd'huiThierry EscaichOrganiste et compositeurChloë CambrelingJournalisteMasterclasse de Thierry Escaich, organiste et compositeur.Modératrice : Chloë CambrelingRésuméLe compositeur Thierry Escaich, cotitulaire de l'orgue de Notre-Dame de Paris, est chargé de composer le Te Deum créé en juin 2025. Ses œuvres sont régulièrement jouées, parfois créées, à la Philharmonie de Paris, où il se produit également en tant qu'organiste. Cette conférence-masterclasse au piano présentera les enjeux contemporains du travail de composition : la création d'œuvres nouvelles aux formats divers étant l'une des missions de la Cité de la musique – Philharmonie de Paris.
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1:09:31
Conférence - David Nesvorný : Formation of Equal-Size Binaries in the Kuiper Belt
Alessandro MorbidelliChaire Formation planétaire : de la Terre aux exoplanètesCollège de FranceAnnée 2025-2026David NesvornýConférence - David Nesvorný : Formation of Equal-Size Binaries in the Kuiper BeltDavid NesvornýSouthwest Research Institute, USARésuméA critical step in the emergence of planets within a protoplanetary disk is the accretion of planetesimals - bodies ranging from 1 to 1,000 kilometers in size - formed from smaller solid constituents. However, this process remains poorly understood, largely due to limited observational constraints on the complex physical mechanisms involved in planetesimal formation. In the outer Solar System, the best place to look for clues is the Kuiper belt, where a population of icy planetesimals survived to this day. We present evidence that Kuiper Belt planetesimals formed via the streaming instability, a process in which aerodynamically concentrated clumps of pebbles undergo gravitational collapse to form 100-kilometer-class bodies. This mechanism explains the high prevalence of equal-sized binaries observed in the Kuiper Belt. The model predicts a broad inclination distribution and a predominance of prograde binary orbits, consistent with observations of trans-Neptunian binaries. Given its robustness across a wide range of protoplanetary disk conditions, the streaming instability is likely to have played a central role in seeding planetesimal formation throughout the Solar System and in other planetary systems as well.
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Conférence - Emmanuelle Passegué : Hematopoietic Stem Cell Aging and Adaptation to Stress
Hugues de ThéCollège de FranceOncologie cellulaire et moléculaireAnnée 2025-2026Hematopoietic Stem Cell Aging and Adaptation to StressConférence - Emmanuelle Passegué : Adaptive and Maladaptive Myeloid Cell ProductionEmmanuelle PasseguéDirectrice de la Columbia Stem Cell Initiative et professeure émérite de génétique et de développement à l'université ColumbiaRésuméAlthough young adult HSCs employ finely tuned mechanisms to balance pro-survival and stress responses, these maintenance strategies provoke vulnerabilities that manifest with continued age, leading to a decline in function. We will examine HSC biology through the lens of antagonistic pleiotropy, whereby the same mechanisms that are important for reproductive fitness form the basis for functional decline during aging. We will particularly highlight the central role of cell cycle regulation, niche cell reliance, inflammatory responses, cellular memory, and distinct metabolic regulation in driving HSC aging features, including expansion of the HSC pool, decreased self-renewal ability, myeloid-biased differentiation, and genomic instability leading to clonal hematopoiesis (CH) and leukemic transformation.
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Conférence - Emmanuelle Passegué : Adaptive and Maladaptive Myeloid Cell Production
Hugues de ThéCollège de FranceOncologie cellulaire et moléculaireAnnée 2025-2026Hematopoietic Stem Cell through the Ages: A Lifetime of Adaptation to Organismal DemandsConférence - Emmanuelle Passegué : Adaptive and Maladaptive Myeloid Cell ProductionEmmanuelle PasseguéDirectrice de la Columbia Stem Cell Initiative et professeure émérite de génétique et de développement à l'université ColumbiaRésuméAlthough highly regulated to maintain stable output of blood cells in health, the hematopoietic system is capable of extensive remodeling in response to external challenges, prioritizing production of certain blood cell types at the expense of others. We will consider how acute insults, such as infections and myeloablation, cause molecular, cellular, and metabolic changes in hematopoietic stem and progenitor cells at multiple levels of the hematopoietic hierarchy to drive accelerated production of mature myeloid cells needed to resolve the initiating insult. Moreover, we will discuss how dysregulation or subversion of these emergency myelopoiesis mechanisms contributes to the progression of chronic inflammatory diseases and solid cancer.
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Conférence - Emmanuelle Passegué : Environmental Crosstalk and Bone Marrow Niche Regulation
Hugues de ThéCollège de FranceOncologie cellulaire et moléculaireAnnée 2025-2026Hematopoietic Stem Cell through the Ages: A Lifetime of Adaptation to Organismal DemandsConférence - Emmanuelle Passegué : Environmental Crosstalk and Bone Marrow Niche RegulationEmmanuelle PasseguéDirectrice de la Columbia Stem Cell Initiative et professeure émérite de génétique et de développement à l'université ColumbiaRésuméIn adult mammals, HSCs reside in the bone marrow (BM) cavity near diverse groups of stromal cells, which maintain the structural integrity of both bone and marrow microenvironments. Interactions among stromal cells and hematopoietic stem and progenitor cells modulate many of the critical functions of the hematopoietic system, including production of specific blood lineages and responses to infection and inflammation. Our understanding of these interactions has grown considerably with application of new technologies that have uncovered how cell populations associate in situ and exchange molecular signals. We will describe important architectural features of the BM cavity and its cellular composition and explore the central role of mesenchymal stromal cells (MSC) as organizers of hematopoietic niches.
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