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A large thermal energy reservoir in the nascent intracluster medium at a redshift of 4.3
No full textInternational audienceMost baryons in present-day galaxy clusters exist as hot gas (), forming the intracluster medium (ICM). Cosmological simulations predict that the mass and temperature of the ICM rapidly decrease with increasing cosmological redshift, as intracluster gas in younger clusters is still accumulating and being heated. The thermal Sunyaev-Zeldovich (tSZ) effect arises when cosmic microwave background (CMB) photons are scattered to higher energies through interactions with energetic electrons in hot ICM, leaving a localized decrement in the CMB at a long wavelength. The depth of this decrement is a measure of the thermal energy and pressure of the gas. To date, the effect has been detected in only three systems at or above , when the Universe was 4 billion years old, making the time and mechanism of ICM assembly uncertain. Here, we report observations of this effect in the protocluster SPT234956 with Atacama Large Millimeter/submillimeter Array (ALMA). SPT234956 contains a large molecular gas reservoir, with at least 30 dusty star-forming galaxies (DSFGs) and three radio-loud active galactic nuclei (AGN) in a 100-kpc region at , corresponding to 1.4 billion years after the Big Bang. The observed tSZ signal implies a thermal energy of , exceeding the possible energy of a virialized ICM by an order of magnitude. Contrary to current theoretical expectations, the strong tSZ decrement in SPT234956 demonstrates that substantial heating can occur and deposit a large amount of thermal energy within growing galaxy clusters, overheating the nascent ICM in unrelaxed structures, two billion years before the first mature clusters emerged at
Sexual selection drives sex difference in adult life expectancy across mammals and birds
No full textInternational audienceAcross human cultures and historical periods, women, on average, live longer than men, a pattern best understood from a comparative evolutionary perspective. Here, we analyzed adult life expectancy in 528 mammal and 648 bird species in zoos. Like humans, 72% of mammals exhibited a female life expectancy advantage, while 68% of birds showed a male advantage, as expected from the harmful effects of sex chromosomes described by the heterogametic sex hypothesis. Yet, sex differences varied widely. In zoos, we found strong evidence that this variation generally correlated with both the mating system and sexual size dimorphism. Although with weaker evidence, the patterns remained consistent in populations from the wild, with an even larger effect of the mating system. Thus, even in zoos, where environmental pressures are largely reduced, precopulatory sexual selection seems to play a fundamental role in shaping sex differences in life expectancy in mammals and birds
Stable magnetic fields and changing starspots on Vega: An ultra-deep decadal survey at Pic du Midi and OHP
No full textInternational audienceAims. Monitoring magnetic and activity variations in A and B stars with ultra-weak magnetic fields is essential to our understanding of the origin and evolution of these fields in this domain of the Hertzsprung-Russell (HR) diagram. Vega is a prototype star of its type and its long-term monitoring offers the most promising opportunity to study these properties.Methods. High-resolution spectrocopic and spectropolarimetric data were gathered with SOPHIE/OHP in 2018 and NARVAL/NEO-NARVAL/TBL in 2018, 2023, and 2024. A total of 13 108 individual spectra of Vega were obtained, which are the basis for the analysis carried out in this work. Magnetic field maps were reconstructed with the Zeeman-Doppler imaging (ZDI) method, while activity maps were reconstructed with an innovative code built for this purpose. These maps were compared to previous results.Results. The rotation period of Vega was confirmed to be very close to the former reference period of 0.678 d. The average magnetic field confirms a negative spot of radial field on the pole with stable strength, while the magnetic maps confirm the long-term stability of an oblique dipole, as well as smaller magnetic features showing up consistently throughout our three observing epochs. However, brightness maps show strong variations of the spot location over a timescale of years (and possibly even shorter). The spot contrast is shown to be very similar in the observations from 2012, 2018, 2023, and 2024, with a normalised spectral amplitude of 0.0003. A direct correlation between the magnetic field and brightness patches could not be revealed in the simultaneous SOPHIE and NARVAL 2018 dataset.Conclusions. Vega’s so-called magnetic mystery has gained complexity since indications point towards the presence of a fossil magnetic field, but also to the presence of a dynamo-generated field, most likely concentrated on equatorial regions
The Science of the Einstein Telescope
No full textEinstein Telescope (ET) is the European project for a gravitational-wave (GW) observatory of third-generation. In this paper we present a comprehensive discussion of its science objectives, providing state-of-the-art predictions for the capabilities of ET in both geometries currently under consideration, a single-site triangular configuration or two L-shaped detectors. We discuss the impact that ET will have on domains as broad and diverse as fundamental physics, cosmology, early Universe, astrophysics of compact objects, physics of matter in extreme conditions, and dynamics of stellar collapse. We discuss how the study of extreme astrophysical events will be enhanced by multi-messenger observations. We highlight the ET synergies with ground-based and space-borne GW observatories, including multi-band investigations of the same sources, improved parameter estimation, and complementary information on astrophysical or cosmological mechanisms obtained combining observations from different frequency bands. We present advancements in waveform modeling dedicated to third-generation observatories, along with open tools developed within the ET Collaboration for assessing the scientific potentials of different detector configurations. We finally discuss the data analysis challenges posed by third-generation observatories, which will enable access to large populations of sources and provide unprecedented precision
Cancer Prevalence across Vertebrates
No full textInternational audienceAbstract Cancer is pervasive across multicellular species, but what explains the differences in cancer prevalence across species? Using 16,049 necropsy records for 292 species spanning three clades of tetrapods (amphibians, sauropsids, and mammals), we found that neoplasia and malignancy prevalence increases with adult mass (contrary to Peto’s paradox) and somatic mutation rate but decreases with gestation time. The relationship between adult mass and malignancy prevalence was only apparent when we controlled for gestation time. Evolution of cancer susceptibility appears to have undergone sudden shifts followed by stabilizing selection. Outliers for neoplasia prevalence include the common porpoise (<1.3%), the Rodrigues fruit bat (<1.6%), the black-footed penguin (<0.4%), ferrets (63%), and opossums (35%). Discovering why some species have particularly high or low levels of cancer may lead to a better understanding of cancer syndromes and novel strategies for the management and prevention of cancer. Significance: Evolution has discovered mechanisms for suppressing cancer in a wide variety of species. By analyzing veterinary necropsy records, we can identify species with exceptionally high or low cancer prevalence. Discovering the mechanisms of cancer susceptibility and resistance may help improve cancer prevention and explain cancer syndromes. See related commentary by Metzger, p. 1
Les variations du niveau de la mer
No full textLe bilan énergétique du système Terre-Atmosphère est un indicateur direct du changement climatique actuel. Ce bilan est défini comme la différence entre le rayonnement solaire entrant et le rayonnement infrarouge sortant. Ce déséquilibre est légèrement positif et entraîne une hausse globale de la température moyenne terrestre ainsi que la fonte des glaces (continentales et marines). La hausse du niveau moyen global de la mer apparaît comme une conséquence directe et un indicateur intégrateur de ce changement climatique global.Au cours du 20e siècle, les enregistrements marégraphiques montrent que le niveau moyen global de la mer a augmenté de 1.2 à 2.1 mm/an. Cette hausse a été confirmée par les données d’altimétrie spatiale. Cette hausse est maintenant mesurée avec une vitesse de 3.6 mm/an depuis 1993. Le réchauffement global des océans combiné à la fonte des glaciers de montagne et des calottes polaires du Groenland et de l’Antarctique contribuent à cette hausse. Si les enregistrements des marégraphes ont suggéré que cette hausse présentait une forte variabilité régionale (à l’échelle du bassin océanique), cette forte variabilité spatiale a été confirmée par ces nouvelles données d’altimétrie spatiale. Cette variabilité régionale est due aux changements de température, salinité ainsi que de la masse qui eux sont induits par les échanges entre les océans et l’atmosphère (stress du vent, flux d’eau douce et de chaleur) ainsi que les apports d’eau douce venant des rivières et des fleuves. Actuellement, 267 millions de personnes dans le monde vivent sur des terres situées à moins de 2 m au-dessus du niveau de la mer. Étudier l'évolution du niveau de la mer est donc d’une importance capitale pour ces populations et les infrastructures côtières associées.Lors de cette présentation, je reviendrai sur mon parcours académique ainsi que sur les résultats que j’ai obtenus lors de mes investigations relatives aux variations du niveau de la mer. Je détaillerai principalement les résultats majeurs de mes activités de recherche notamment ceux réalisés lors d’encadrements. Enfin, je proposerai des perspectives relatives à mes investigations futures à court et plus long termes
Quantifying Miocene thin- and thick-skinned shortening in the Baous thrust system, SW French Alpine Front
No full textInternational audienceAt the southernmost front of the southwestern French Alps, the Baous thrust system is a key marker of Alpine deformation. Based on detailed surface data and a balanced, sequentially restored cross-section, this study shows that the SSW-verging Baous thrust is rooted in a deep-seated basement thrust, kinematically linked to shallower thrusts detached within Triassic evaporites. This basement thrust reactivates an inherited, north-dipping Jurassic extensional fault, which controls the development of the Saint-Barnabé anticline in the north. To the south, the Courmettes structures display fault-bend fold geometries and associated shortcut thrusts. Restoration constrains a total horizontal shortening of 5 km (31.4 %), partitioned between the sedimentary cover (43 %, ~2.1 km) and the basement (57 %, ~2.9 km), reflecting both thin- and thick-skinned tectonics. The Courmettes-Vence syn-tectonic basin, located in the footwall, provides key temporal constraints on thrust development. Six deformation stages, identified through sequential restoration between the Burdigalian and Messinian, highlight increasing shortening rates: 0.17 km/Myr (Burdigalian-Tortonian), 0.37 km/Myr (Tortonian), and 1.16 km/Myr (Messinian). Kinematic relationships indicate a primarily in-sequence deformation propagation toward the Alpine foreland: initial basement-involved thrusting was followed by activation of thin-skinned thrusts, then overprinted by out-of-sequence reactivation of the basement thrust. The proposed kinematic model is consistent with recent onshore and offshore seismic interpretations, supporting its robustness and relevance for understanding the tectonic evolution of the southwestern Alpine front. These results emphasize the role of inherited extensional structures (here Jurassic in age) in shaping fold-and-thrust belts and controlling thrust geometry, deformation style, and present-day distribution of seismicity
Geological record of atmospheric nitrogen fixation during explosive supereruptions: The case of Tecopa Basin, California
No full textInternational audienceNitrate in dry sedimentary records has long been associated with long‐term atmospheric deposition and biological activity. Recent discoveries of nitrate with an atmospheric origin in volcanic deposits from large eruptions have been tentatively linked to volcanic lightning. Lightning can break the chemical bonds of stable molecules like dinitrogen, releasing NO, which is rapidly oxidized by ozone, forming atmospheric nitrate with a high O‐anomaly. Another possible source of nitrate in volcanic deposits is atmospheric long‐term deposition. To confirm and quantify the origins of nitrate in volcanic deposits, we compare for the first time the multi‐isotopic (O, N) signatures of nitrate in sediments and volcanic deposits from supereruptions. Samples were taken in the Tecopa Basin (California), where the dry conditions have been favorable to sample preservation. The mean O and N isotopic compositions in nitrate from sediments (Δ O = 12 ± 1‰ and δ N = 2 ± 2‰ (2 σ )) and volcanic ash layers (Δ O = 19 ± 5‰ and δ N = −5 ± 3‰ (2 σ )) are substantially different. Only a massive and fast production of atmospheric nitrate during supereruptions can explain the higher Δ O values in volcanic ash layers. The most plausible N‐fixation mechanism of this atmospheric nitrate is volcanic lightning. Our results indicate that volcanic lightning from supereruptions such as Lava Creek Tuff (0.64 Ma, Yellowstone) could fix up to ∼100 Tg of N. Alteration and erosion of nitrate‐rich volcanic deposits are expected to free large quantities of nitrate into the environment, which living organisms assimilate and could play a significant role in developing the local biosphere
Multidisciplinary End-to-End Document-Level Relation Extraction from Scientific Literature
No full textInternational audienceThe increasing impact of global change on coastal areas necessitates effective collaboration among stakeholders to develop sound environmental protection policies. However, the vast number of scientific publications and the interdisciplinary nature of the field make it challenging to accurately identify and extract relevant information. Current methods for analyzing coastal region literature are limited in handling complex document-level relations, impeding the development of comprehensive Knowledge Bases (KBs) essential for informed decision-making. Therefore, we introduce CoastRED, a corpus of 416 scientific abstracts focused on coastal regions, designed for interdisciplinary end-to-end Document-level Relation Extraction (DocRE), leveraging the ARDI framework(Actors, Resources, Dynamics, and Interactions) to automatically identify key entities and their roles in coastal systems. We present DUNJERE—an end-to-end model integrating Mention Detection, Coreference Resolution, Entity Typing, and Relation Extraction. Based on a U-Net architecture, DUNJERE approaches Relation Extraction as a semantic segmentation task, enhancing its performance in an end-to-end setting. Evaluations on the DocRED and ReDocRED datasets demonstrate state-of-the-art performance, while experiments on CoastRED highlight its potential to advance coastal system research by providing a robust tool for document analysis and KB construction
Prospective Venus Cloud trace species detectability as inferred from Hubble
No full textInternational audienceThe composition and chemical processing occurring within the Venus atmosphere is derived by a combination of direct observation (both in-situ and remote) and chemical and climate modeling (Widemann et al. 2024, Marcq et al. 2018). Chemical modeling and atmospheric properties retrievals from observations are interdependent efforts. Venus’s bulk atmosphere is composed of CO2 (96.5%) and N2 (3.5%), while SO2 (~0.015%), Argon (0.007%) and water (0.002%) round out the top 5 gas species present in the Venus atmosphere. Observations and chemical modeling indicate that Venus's clouds also host a myriad of sulfur, oxygen, nitrogen, hydrogen, chlorine, carbon and oxygen trace gas species. While it is understood that the Venus clouds are dominantly composed of H2SO4 aerosol, and that the H2SO4 gas within the atmosphere is formed by chain reaction of SO2 photolysis leading to formation of SO3 and the interaction of SO3 with H2O—many questions remain about what controls the abundance of H2SO4, H2O and SO2 in the Venus atmosphere (Marcq et al. 2018, Bierson et al. 2020, Rimmer et al. 2021, Dai et al. 2022). Unequivocal answers to these questions are dependent on how precisely we can identify and quantify the other trace gas and aerosol forming species present in the atmosphere and their propensity to interact with Venus’s sulfur, oxygen and water budgets. (Mogul et al. 2021, Rimmer et al. 2021, Jiang et al. 2023, Jessup et al. 2020)Progress in resolving these questions is being made as chemical and climate modeling become increasingly sophisticated (Stolenzbach et al. 2023, Dai et al. 2022, Dai et al. 2024). Likewise, efforts to advance and improve lab and theoretical studies of the physical properties of gases and aerosols that may be present in the Venus atmosphere are on-going (Frandsen et al. 2024, Skog et al. 2024, Jiang et al. 2023, Heays et al. 2017 Heays et al. 2023). These advances and the anticipation of several new Venus missions, motivates the review/re-analysis of several previously obtained remote/in-situ datasets (Mogul et al. 2021, Mahieux et al. 2024, Mahieux et al. 2023, Lincowski et al. 2021). As a result, several sulfur-based species previously not conclusively observed have now been definitively detected within remote sensing data (Mahieux et al. 2023), while debate rages on about species detected via in situ observation opportunities (Lincowski et al. 2021, Mogul et al. 2021). Several gases recently positively detected by SOIR have absorption at UV wavelengths coincident with previously obtained Hubble Space Telescope spectra (Jessup et al. 2015, Jessup et al. 2020). We present a summary of the detectability of these species in the previously obtained Hubble data. We discuss what these and the recent SOIR retrievals may mean for anticipated monitoring of the Venus cloud top and middle atmosphere at UV and other wavelengths via the EnVision/VenSpec instrument (Marcq et al. 2021). We also discuss to what extent the detectability of these species at UV wavelengths impacts open controversial in-situ detections (Mogul et al. 2021); especially those that may directly impact the sulfur cycle or other cloud level atmospheric constituents (Rimmer et al. 2021).