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MEGATRON: Reproducing the Diversity of High-Redshift Galaxy Spectra with Cosmological Radiation Hydrodynamics Simulations
No full textInternational audienceWe present the MEGATRON suite of cosmological radiation hydrodynamics simulations following the formation of Milky Way-mass galaxies from the earliest cosmic epochs when Population III stars form to Cosmic Noon. The suite represents the first set of cosmological simulations that couples a vast non-equilibrium thermochemistry network of primordial species, metals, and molecules to multifrequency, on-the-fly radiation transport, allowing us to directly predict the spectral properties of early galaxies. By initializing the simulations at zero metallicity, resolving haloes well below the atomic cooling threshold, reaching parsec-scale resolution, and modeling a Milky Way-mass environment, we aim to address four key science themes: 1) Star formation at cosmic dawn, 2) Galaxy formation and the interstellar medium in the epoch of reionization, 3) The circumgalactic medium towards cosmic noon, and 4) Reionization in a local volume environment and near-field cosmology. In this introductory work, we present an overview of the physical characteristics of high-redshift MEGATRON galaxies and their environment at . We present a library of simulated galaxy spectra and demonstrate how the diversity of galaxy spectra seen by JWST is naturally reproduced in the context of a CDM cosmology. This project represents a step towards making more direct comparisons between simulations and observations and will enable future work to both optimize methods for inferring galaxy properties from observations and to elucidate the physics that governs galaxy formation in the early Universe
Process evaluation of a school-based vaccination intervention to improve HPV vaccine coverage: A mixed-method study embedded in the French PrevHPV cluster randomized controlled trial
No full textInternational audienceBackgroundHuman papillomavirus vaccine coverage (HPV VC) remains suboptimal in many countries. French authorities launched the PrevHPV research program, which included a cluster randomized controlled trial (cRCT) to evaluate the effectiveness of an ‘at-school vaccination’ intervention. Within this trial, we conducted a process evaluation of this intervention, specifically analyzing (i) its implementation, (ii) its mechanisms of impact, and (iii) the contextual factors influencing implementation (facilitators/barriers).MethodWe conducted a mixed-method study embedded in the PrevHPV cRCT (April 2021–April 2022). ‘At-school vaccination’ consisted of vaccination day(s) on school premises where mobile vaccination teams (MVTs) initiated HPV vaccination free of charge for eligible adolescents (i.e., non-vaccinated adolescents aged 11+). Quantitative data were collected through activity reports and self-administered questionnaires of adolescents and school staff. Qualitative data collected through six focus groups with school staff and MVTs were analyzed using thematic analysis.ResultsOf the 31 schools (14,772 adolescents) randomized to implement ‘at-school vaccination’, 12 (39 %) dropped out. Among the participating schools, analysis of implementation showed that 17 % of adolescents returned valid consent forms, of whom 89 % initiated vaccination. MVTs played a central role in implementing vaccination day(s), supported by several school staff (e.g., school nurses, education assistants). Regarding mechanisms of impacts, satisfaction with the vaccination days was high among adolescents and school staff. The intervention generated both positive and negative group effects among adolescents. Contextual factors that facilitated implementation included the preparation of a list of adolescents to be vaccinated and the availability and motivation of school staff. The main barriers related to the management of consent forms and missing health records.ConclusionWe formulated recommendations for implementing at-school vaccination, which may be particularly helpful for the French school HPV vaccination campaigns that were scaled up nationally in 2023. We also discussed potential macro-level improvement strategies, involving modifications to the legislative framework
Equivariant Splitting: Self-supervised learning from incomplete data
No full textSelf-supervised learning for inverse problems allows to train a reconstruction network from noise and/or incomplete data alone. These methods have the potential of enabling learning-based solutions when obtaining ground-truth references for training is expensive or even impossible. In this paper, we propose a new self-supervised learning strategy devised for the challenging setting where measurements are observed via a single incomplete observation model. We introduce a new definition of equivariance in the context of reconstruction networks, and show that the combination of self-supervised splitting losses and equivariant reconstruction networks results in unbiased estimates of the supervised loss. Through a series of experiments on image inpainting, accelerated magnetic resonance imaging, sparse-view computed tomography, and compressive sensing, we demonstrate that the proposed loss achieves state-of-the-art performance in settings with highly rank-deficient forward models. The code is available at https://github.com/vsechaud/Equivariant-Splittin
Les enjeux communicationnels et interactionnels de l’analyse pragma-énonciative des points de vue (2) : pour une approche holistique des points de vue dans des textes complexes et complets
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Spin-filament alignments to unravel galaxy evolution and model intrinsic alignments
No full textInternational audienceBy the 2040s, several all-sky surveys will have transformed our view of the large-scale structure. However, one of the major outstanding questions in astrophysics will remain: understanding how galaxies acquire and evolve their angular momentum and how this connects to the cosmic web. Measuring the alignments between galaxy spins and cosmic filaments across cosmic time, and understanding what this reveals about galaxy evolution, requires surveys that also characterise intrinsic alignments, i.e. correlations in galaxy shapes produced by the cosmic web itself rather than by lensing. Intrinsic alignments are a major source of systematic error in weak-lensing measurements of the fundamental parameters of the Universe. Addressing both questions together will necessitate new types of MOS surveys that combine kinematic information with high-completeness redshifts down to at least 24-25mag. To achieve our science goals, we require a new generation of wide-field spectroscopic facilities that can obtain spin-filament alignment measurements for millions of galaxies while simultaneously delivering sub-Mpc resolution of the cosmic web and spatially-resolved kinematics required to map the spin-filament connection at the level of individual galaxies within their local cosmic environment. Such a program would provide a unique legacy survey of galaxies and cosmic structures from kiloparsec to megaparsec scales, establishing ESO's leadership in bridging the physics of galaxy evolution with the systematic-control requirements for Stage-IV cosmological surveys
Biology and Clinical Management of Non-V600 BRAF Alterations in NSCLC
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Le « eux » et le « nous » : rapports conflictuels inter-groupes chez les animaux sociaux
No full textInternational audienceOne of the great constants in the history of human societies is the opposition between “us,” which embodies all conceivable positive values, and “them,” which is associated with everything perceived as negative. Contempt or rejection of “the other” (clan, tribe, race, nation, region, class, caste, ethnic or religious group, family) is the principle behind all ethnocentrism. But the opposition between "us" and "them" is only the extension, in the cultural-symbolic order specific to our species, of a general defense mechanism present throughout the animal kingdom, from eusocial insects to primates: defense of the “close” or the “same” (whether related or unrelated) against what is perceived as distant, different, foreign, or outside one's own group. In the case of human societies, “us” and “them” can take very different forms, as groups are built on cultural foundations. While they have succeeded in bringing together millions (even billions) of individuals into coherent and relatively peaceful social units, human societies have constantly multiplied the types of us/them opposition, and therefore the potential conflicts between groups.L'un des grands invariants dans l'histoire des sociétés humaines réside dans l'opposition entre un « nous », chargé de toutes les valeurs positives imaginables, et un « eux », associé à tout ce qui est perçu comme négatif. Le mépris ou le rejet de l'« autre » (clan, tribu, ethnie, race, nation, région, groupe religieux, etc.) est le principe de tout ethnocentrisme. Mais l'opposition eux/nous n'est que le prolongement, dans l'ordre culturel-symbolique propre à notre espèce, d'un mécanisme général de défense présent dans l'ensemble du règne animal, des insectes eusociaux aux primates : défense du « proche » ou du « même » (apparenté ou nonapparenté) par rapport à ce qui est perçu comme lointain, différent, étranger, extérieur à son propre groupe. Dans le cas des sociétés humaines, le « nous » et les « eux » peuvent prendre des formes très variables dans la mesure où les groupes se construisent sur des bases culturelles. En même temps qu'elles ont réussi à rassembler des millions (voire des milliards) d'individus dans des unités sociales cohérentes et relativement pacifiées, les sociétés humaines n'ont cessé de multiplier les types d'opposition eux/nous, et donc les conflits possibles entre les groupes
Primordial axisymmetric compact objects in General Relativity
No full textInternational audienceThe search for exact solutions describing asymptotically FLRW compact objects in General Relativity (GR) remains a notoriously challenging problem. To a large extent, progress has been restricted to the spherically symmetric sector, with the exception of the Kerr-de Sitter and Thakhurta solutions. In this work, we present two new results that advance the description of axisymmetric compact objects embedded in a cosmological background. We first introduce a new solution-generating technique allowing one to construct non-stationary and axisymmetric solutions of the self-interacting Einstein-Scalar system. Using this method, we present the first exact solution which describes a dynamical axisymmetric black (or white) hole embedded in an expanding or contracting cosmology. We provide a detailed investigation of its properties, and in particular its dynamical trapping (or anti-trapping) horizons. To that end, we use the mean curvature vector (MCV) which stands as a natural generalization of the Kodama vector beyond spherical symmetry. The norm of this vector provides a foliation-independent quantity to locate the trapped/anti-trapped and untrapped regions and characterize the causal nature of a given geometry without specific symmetry requirement. The solution-generating method and the techniques to analyze the new solutions provide new powerful tools to further explore the description and the phenomenology of dynamical compact objects embedded in cosmology, in particular those of primordial black holes