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Do penguins care about on-paper boundaries? Conservation implications of spatio-temporal winter consistency in an Antarctic sentinel species
No full textInternational audienceUnderstanding the spatial and temporal at-sea distribution of marine predators throughout their annual cycle is crucial for identifying priority areas for conservation in the Southern Ocean. However, the delimitation of boundaries of the proposed East Antarctic Marine Protected Area (EAMPA) is largely based on species' breeding distributions, overlooking seasonal and annual shifts driven by sea ice variability. We studied the non-breeding distribution and space use of a key Antarctic eco-indicator species, the Adélie penguin, by tracking 62 individuals from Terre Adélie over five years using geolocators. Moulting occurred in areas of low sea ice concentration (SIC), whereas during winter, penguins migrated on average 1550 km westward from the colony to areas along the sea ice edge with high SIC (75 %). The inter-annual overlap of wintering grounds revealed high spatiotemporal consistency, indicating productive regions. Despite variability across years, tracked individuals moulted predominantly outside the proposed EAMPA, and only 16.3 % of winter locations fell within its boundaries. These findings provide new insights into the non-breeding ecology of Adélie penguins, and highlight a relevant gap in spatial coverage of critical moulting and wintering areas of this highly mobile species in the current EAMPA proposal
Theoretical filters for shift-symmetric Horndeski gravities
No full textInternational audienceWe investigate the structure of nontrivial maximally symmetric vacua and compact-object solutions in shift-symmetric scalar-tensor theories. Focusing on Horndeski gravity, we derive consistency conditions directly from the field equations to identify the subclasses that admit Minkowski and de Sitter vacua with a nontrivial scalar field. In doing so, we obtain a filtering mechanism that operates independently of observational data. In this context, we introduce the notion of stealth vacua, where the scalar field remains active without altering the vacuum. Following this, we examine the theoretical framework of Horndeski theories that admit homogeneous geometries and we extract the implicit form of the solution pertaining to the entire family of theories. Building upon these frameworks, we construct exact solutions in beyond-Horndeski gravity by applying a linear disformal transformation to the regularized Einstein-Gauss-Bonnet black hole. This procedure yields solitonic spacetimes with scalar hair as well as black holes carrying primary scalar hair, demonstrating how disformal maps can qualitatively modify solution properties. We delineate the parameter space in which the transformation is well-defined and analyze the solutions. Our results provide both a principled criterion for selecting viable Horndeski models and a framework for exploring rich solution spaces in beyond-Horndeski gravity
Study on the equation-of-state with light clusters and hypernuclei
No full textInternational audienceHeavy-ion collision experiments offer a unique opportunity to explore the early stages of the Universe by creating matter under extreme conditions of high temperature and baryon density. The properties of such matter are governed by the equation-of-state (EoS), which remains a central focus of investigation from both experimental and theoretical perspectives. Flow harmonics are among the most sensitive observables for probing the EoS, as they strongly reflect the underlying interactions and degrees of freedom of the system. In this article, we review the current status of our understanding of the EoS based on microscopic transport models, emphasizing comparisons with experimental data in the few GeV energy range
Probing of EoS with clusters and hypernuclei
No full textInternational audienceThe study of the nuclear equation-of-state (EoS) is a one of the primary goals of experimental and theoretical heavy-ion physics. The comparison of recent high statistics data from the STAR Collaboration with transport models provides a unique possibility to address this topic in a yet unexplored energy domain. Employing the microscopic n-body Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) transport approach, which allows to describe the propagation and interactions of hadronic and partonic degrees of freedom including cluster and hyper-nucleus formation and dynamics, we investigate the influence of different EoS on bulk observables, the multiplicity, and rapidity distributions of protons, s and clusters up to A=4 as well as their influence on the collective flow. We explore three different EoS: two static EoS, dubbed 'soft' and 'hard', which differ in the compressibility modulus, as well as a soft momentum dependent EoS. We find that a soft momentum dependent EoS reproduces most baryon and cluster observables, including the flow observables, quantitatively
Search for long-lived particles using displaced vertices of oppositely charged leptons in 140 fb of pp collisions at TeV with the ATLAS detector
No full textInternational audienceA search is presented for long-lived particles decaying into an oppositely charged lepton pair, , , or , that form a vertex within the inner tracking system of the ATLAS detector at the Large Hadron Collider, displaced from the primary proton-proton interaction region. The analysis uses the 140 fb of Run-2 data collected at TeV by the ATLAS experiment in 2015-2018. The results of the analysis are interpreted in the context of three benchmark models covering masses from 0.1 to 2.2 TeV and a range of mean proper lifetimes times the speed of light from 1 to 10000 mm. The first model is a generic boson pair-produced by a new heavy scalar, with the decaying into lepton pairs. The remaining two models are -parity violating supersymmetric models in which the lightest neutralino decays into (, ). The models differ by the mode of production of the , which can be produced via the decay of pairs of gluinos or of pairs of charginos and neutralinos (, , or ). Although each benchmark sample includes pair-produced LLPs, only a single vertex is required to be reconstructed. No dilepton displaced vertex candidate is observed and the results are presented as upper limits on the production cross-sections. This analysis sets leading limits on the production cross-sections for multiple models, including parameter space that has never been directly probed
Opportunities in AI/ML for the Rubin LSST Dark Energy Science Collaboration
No full textThe Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will produce unprecedented volumes of heterogeneous astronomical data (images, catalogs, and alerts) that challenge traditional analysis pipelines. The LSST Dark Energy Science Collaboration (DESC) aims to derive robust constraints on dark energy and dark matter from these data, requiring methods that are statistically powerful, scalable, and operationally reliable. Artificial intelligence and machine learning (AI/ML) are already embedded across DESC science workflows, from photometric redshifts and transient classification to weak lensing inference and cosmological simulations. Yet their utility for precision cosmology hinges on trustworthy uncertainty quantification, robustness to covariate shift and model misspecification, and reproducible integration within scientific pipelines. This white paper surveys the current landscape of AI/ML across DESC's primary cosmological probes and cross-cutting analyses, revealing that the same core methodologies and fundamental challenges recur across disparate science cases. Since progress on these cross-cutting challenges would benefit multiple probes simultaneously, we identify key methodological research priorities, including Bayesian inference at scale, physics-informed methods, validation frameworks, and active learning for discovery. With an eye on emerging techniques, we also explore the potential of the latest foundation model methodologies and LLM-driven agentic AI systems to reshape DESC workflows, provided their deployment is coupled with rigorous evaluation and governance. Finally, we discuss critical software, computing, data infrastructure, and human capital requirements for the successful deployment of these new methodologies, and consider associated risks and opportunities for broader coordination with external actors
Measurement of differential -channel single top (anti)quark production cross-sections at 13 TeV with the ATLAS detector
No full textInternational audienceThe production of single top quarks and top antiquarks via the -channel exchange of a virtual boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider. The full Run 2 data sample recorded with the ATLAS detector in the years 2015-2018 is used, corresponding to an integrated luminosity of 140 fb. The absolute and normalised production cross-sections are measured differentially as a function of the transverse momentum and absolute rapidity of the top quark and top antiquark. In addition, the ratio of top quark to top antiquark production cross-sections is measured. The measured distributions are compared with next-to-leading-order quantum chromodynamics predictions obtained with different combinations of matrix-element generators, parton-shower programs and proton parton distribution functions, as well as to next-to-next-to-leading-order calculations. Overall, good agreement is observed between the measurements and the theoretical predictions. For most measured distributions, the sensitivity to differences between the predictions is limited by the systematic uncertainties in the measurement. The measured differential distributions are also interpreted in an effective field theory approach to constrain the Wilson-Coefficient associated with a four-quark operator. The interpretation accounts for the effect of the selection efficiency, which is altered significantly by non-zero contributions from
Impact of oxic and thermal transient phases on corrosion of carbon steel in different cementitious media: insights from new in situ experiments
No full textInternational audienceThe impact of oxic and thermal transient phases on corrosion of carbon steel in a cementitious environment was studied through three in situ experiments (Tournemire underground research laboratory, France). For 2 years, heated metallic samples (80°C) were placed in direct or indirect contact with two different cementitious materials: a low-pH bentonitic cement grout (BCG) and a Portland cement paste material (CEM I). Mineralogical and microstructural analyses were carried out in an attempt to identify the combined effects of pH, chemistry and microstructure properties associated with such specific cementitious media on steel corrosion mechanisms. Additionally, in situ electrical resistance corrosion sensors allowed continuous monitoring of the corrosion rates corresponding to each of the three field experiments. Post-mortem characterization indicated that metallic samples embedded in low-pH BCG were heavily damaged and exhibited high corrosion rates. Conversely, steel samples in contact with a highly alkaline CEM I environment appeared to be much less impacted by corrosion processes and revealed extremely low corrosion rate values. A comparison between these field experiments observations and results previously obtained through complementary laboratory mock-up tests finally enabled the evaluation of the impact that variations in geometrical/design aspect existing between in situ and laboratory tests can induce on material degradation
GATE 10 Monte Carlo particle transport simulation: I. Development and new features
No full textInternational audienceWe present GATE version 10, a major evolution of the open-source Monte Carlo simulation application for medical physics, built on Geant4. This release marks a transformative evolution, featuring a modern Python-based user interface, enhanced multithreading and multiprocessing capabilities, the ability to be embedded as a library within other software, and a streamlined framework for collaborative development. In this Part 1 paper, we outline GATE’s position among other Monte Carlo codes, the core principles driving this evolution, and the robust development cycle employed. We also detail the new features and improvements. Part 2 will focus on the architectural innovations and technical challenges. By combining an open, collaborative framework with cutting-edge features, such a Monte Carlo platform supports a wide range of academic and industrial research, solidifying its role as a critical tool for innovation in medical physics
Contrasting Anthropogenic Drivers Behind Asymmetric Warming in the Arctic and Antarctica
No full textInternational audienceSurface air temperature (SAT) in polar regions is rising faster than the global average. This study analyzes the rapid increase in anthropogenic influences throughout the industrial period on Arctic and Antarctic warming, utilizing climate models. Our results show that while the SAT trend in the Arctic due to greenhouse gas (GHG) forcing is approximately 0.6 °C/decade, twice that of land use (LU) forcing at 0.3 °C/decade, the amplification of Arctic warming from LU forcings (with an amplification factor of 2.37) is stronger than the GHG forcings (amplification factor of 2.25). Anthropogenic aerosols cool the Arctic 1.5 times more than Antarctica, driven by higher aerosol concentrations from long-range pollutant transport from lower latitudes. Since 1950, rapid industrialization in the Northern Hemisphere has caused Arctic warming to accelerate, with SAT rising by 0.34 °C/decade due to anthropogenic forcings—over twice the global average of 0.17 °C/decade. In contrast, Antarctic warming has remained closer to global trends, buffered by its remoteness from the anthropogenic influence. Under the high-emission scenario (RCP8.5), both polar regions are projected to experience substantial temperature increases by the end of the 21st century, underscoring the significant role of human activities in polar warming and the need for targeted interventions addressing regional and global changes in LU, GHG emissions, and anthropogenic aerosols.</jats:p