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Differential behavioural responses of pinnipeds to airborne food odours using two experimental paradigms
No full textInternational audienceOlfaction plays an important role in mammalian behaviour, but its biological function, particularly in food detection and discrimination, remains poorly understood in pinnipeds. This study investigated the ability of captive pinnipeds to discriminate between food-related airborne odours and display differential responses. During both sequential and simultaneous presentations, we used four types of food-related odours – oily fish, leanfish, squid, and trout - with four different species: California sea lions (Zalophus californianus), South American sea lions (Otaria flavescens), South American fur seals (Arctocephalus australis), and harbour seals (Phoca vitulina). Behavioural responses, including the number and duration of approaches and nostril openings, were analysed using Bayesian models. Individuals from all four tested pinniped species demonstrated olfactory discrimination,responding more to food-related odours than to the control odour (water). The trout odour elicited the strongest responses, suggesting marked differential behaviour; however, this result should be interpreted with caution, as the trout odour was obtained from a live fish, whereas the other food odours were collected from thawed food items. A stronger response for oily fish over lean fish was observed in sequential but not in simultaneous presentations, highlighting the possible effect of presentation mode on olfactory discrimination. The squid odour did not induce significant responses, possibly due to dietary experience in captivity. Our results confirm that pinnipeds can discriminate between food sources using olfaction, supporting its potential role in foraging behaviour. Future research should investigate these abilities in captive and wild populations, and in the aquatic environment,to assess their ecological relevance
G-Score, the Maximum Cardinality Matching Gn Series as a Benchmark for Quantum Computers
No full textInternational audienceThe Maximum Cardinality Matching (MCM) Gn series represents a well-established set of problems designed to evaluate the capabilities of optimization heuristics. These problems have been instrumental in probing the optimization potential of various DWave quantum computers, offering insights into their performance and limitations. Complementary to the NP-hard yet unconstrained MaxCut problem used in the Q-Score benchmark, the MCM Gn series provides a constrained seriesof problem that further challenge quantum optimization techniques. In this paper, we introduce the G-score benchmark specifically tailored to assess the capabilities of quantum optimization heuristics such as Quantum Annealing (QA) and the Quantum Approximate Optimization Algorithm (QAOA) or any other heuristic that can be relevant on quantum computers. This score aims to offer a comprehensive metric for evaluating the effectiveness of these methods in solving complex optimization problems
Simulation-Based Cosmological Mass Calibration of XXL Galaxy Clusters using HSC Weak Lensing
No full textInternational audienceWe present a cosmological analysis of the X-ray-selected galaxy cluster sample from the XXL survey, employing a simulation-based inference (SBI) framework to jointly constrain cosmological parameters and X-ray scaling relations through forward modeling of cluster counts, X-ray observables, and weak-lensing measurements. Our analysis combines X-ray data from the XMM-XXL survey with shear measurements from the three-year shape catalog of the Hyper Suprime-Cam Subaru Strategic Program. The analysis focuses on the XXL C1 sample, comprising 171 clusters for abundance modeling, a subset of 86 clusters located within the XXL-N region for lensing-based mass calibration, and 162 clusters with X-ray temperature and luminosity measurements used to constrain scaling relations. Using the density-estimation likelihood-free inference (DELFI) algorithm, we construct a forward model with 12 parameters that incorporates the XXL selection function and cluster population modeling and accounts for key systematic effects including cluster miscentering, photometric redshift bias, and mass-dependent weak-lensing bias. Our SBI analysis yields a constraint on the cosmological parameter , with an additional 3% systematic uncertainty from neural network stochasticity. The result is consistent with Planck and recent cluster-based measurements. The inferred temperature-mass relation is consistent with self-similar expectations within uncertainties, whereas the luminosity-temperature relation exhibits a slope steeper than the self-similar prediction. From the resulting posterior distribution of the forward model, we derive lensing-calibrated mass estimates for all individual XXL clusters with measured X-ray temperatures or luminosities. These results provide a self-consistent mass calibration for future multi-probe cosmological analyses of the XXL sample
In-flight calibration of the INTEGRAL/IBIS Compton mode: Application to the Crab Nebula polarization
No full textInternational audienceThe INTEGRAL satellite explored the gamma-ray sky since its launch on October 17, 2002, and until the end of its scientific operation on February 28, 2025. A large fraction of the available data is still largely untouched, due to the complexity of analysis. We describe the latest in-flight calibration of the Compton mode of the INTEGRAL/IBIS telescope, taking into account more than twenty years of data. The spectroscopy and polarization of the standard candle that is the Crab Nebula is analyzed in detail. We operate the IBIS telescope as a Coded mask Compton telescope, using the Crab Nebula to refine the calibration, as is usually done for high-energy instruments. We have determined the spectroscopic and polarimetric properties of the IBIS Compton mode and their evolution along the entire duration of the mission. In addition, the long-term evolution of the Crab Nebula's polarization has been successfully measured and compared with other high-energy experiments. We could estimate the energy dependence of the Crab Nebula polarization in four bands between 200 keV and 1 MeV. In particular, the detection of polarized emissions strictly above 400 keV makes it the highest energy measurement ever performed for the Crab Nebula. A Python library was also made publicly available to analyze processed data
Constitution de la base de données du projet CIPRHES : échantillons national et local
No full textLe projet CIPRHES a pour objectif d’apporter des réponses aux questions de recherche soulevées par l’utilisation de la plateforme de prévision des étiages PREMHYCE depuis son lancement opérationnel en 2018. Pour répondre à ces questions présentées sous la forme de défis scientifiques, différents groupes de travail ont été mis en place. Les groupes de travail 3 (« Développer une modélisation hydrométéorologique intégrée pour la prévision des étiages ») et 5 (« Mettre en place et appliquer des « crash tests » pour évaluer les performances, la robustesse et l’utilité des prévisions ») se basent sur des modélisations et prévisions obtenues à l’aide des modèles hydrologiques implémentés dans la plateforme. Pour alimenter ces modèles, des données de précipitations, d’évapotranspirations et de débits sont nécessaires. Deux échantillons ont été produits dans le cadre du projet CIPRHES : un échantillon national pour l’évaluation globale des chaines de prévision et un échantillon local sur le bassin de la Meuse pour évaluer les modèles semi-distribués mis en place dans le groupe de travail 3. Ce document présente les différents travaux menés pour la préparation de la base de données du projet CIPRHES
ACROPOLIS: Munich urban CO2 sensor network
No full textInternational audienceUrban areas are major contributors to anthropogenic CO2 emissions, yet detailed monitoring remains a challenge due to the cost and operational constraints of traditional sensor networks. As a scalable alternative, we established the ACROPOLIS (Autonomous and Calibrated Rooftop Observatory for MetroPOLItan Sensing) network in the Munich metropolitan area, using mid-cost sensors to enable dense, city-scale observation. This work outlines the development of the hardware and software of the system, its performance and the first 1.5 years of operation, during which more than 90 million CO2 measurements were collected in urban, suburban and rural environments. The primary goal was to evaluate whether mid-cost Vaisala GMP343 sensors, when combined with manufacturer internal corrections and environmental stabilization, can reliably measure CO2 concentrations with sufficient accuracy to resolve urban gradients. We implemented a fully automated 2-point calibration procedure using synthetic dry reference gases and conducted a multi-week side-by-side comparison with a high-precision Picarro reference instrument to assess sensor performance. Our results show that, despite inter-sensor variability in temperature sensitivity, the hourly aggregated mean root mean square error (RMSE) of all sensors is 1.16 ppm with a range of 0.57 to 2.58 ppm. For the specific sensor housed in our second-generation enclosure with PID-controlled heating, the performance improved from 0.9 to 0.6 ppm RMSE. Analysis of spatial and temporal patterns reveal distinct seasonal cycles, urban–rural concentration gradients, and nighttime accumulation events, consistent with expected biogenic and anthropogenic activity, and atmospheric transport mechanisms. We conclude that mid-cost urban networks can provide scientifically valuable, spatially highly resolved greenhouse gas observations when supported by appropriate calibration and stabilization techniques. The open-source design and demonstrated performance of the ACROPOLIS network establish a blueprint for future deployments in other cities seeking to advance emissions monitoring and urban climate policy
Low-noise generation of UV dispersive wave emission at 100 kHz
No full textInternational audienceWe experimentally demonstrate efficient generation of tunable UV pulses at 100 kHz via resonant dispersive wave emission in an argon-filled hollow capillary. We measure few µJ UV pulse energies both in linear and circular polarization. The dispersive wave emission is driven by 1030 nm 28 fs pulses generated by an ytterbium laser temporally compressed in a single stage multipass cell. The UV source has a short-term (over a 1 s time scale) relative intensity noise of 0.58%. Coupled with the high repetition rate and the versatile polarization state, this makes it a relevant source for statistically demanding spectroscopy
Global distribution and changes of leaf-level intrinsic water use efficiency and their responses to water stress
No full textInternational audienceIntrinsic water use efficiency (iWUE) at the leaf level measures water expenditures by terestrial plants during photosynthesis, yet its global spatiotemporal dynamics and responses to water stress remain poorly understood. Using machine-learning models and carbon isotope observations in C3 foliage, here we elucidate global patterns, trends, and water-stress responses of leaf iWUE. We find high iWUE in cold, arid regions and lower values in warm, humid areas. From 2001 to 2020, global iWUE increases at 0.2 ± 0.02 μmol mol-1 year-1, with strong biome specific differences. Grasslands exhibit the highest mean iWUE but the slowest increase, whereas evergreen broadleaf forests show the lowest iWUE yet the fastest increase. iWUE rises with increasing water stress, but the rate of growth diminishes as water stress intensifies. Vapor pressure deficit influence iWUE more broadly than soil moisture. The ecological optimality model reproduces the spatial patterns of leaf iWUE and identifies vapor pressure deficit as the dominant driver, but overestimates mean iWUE and its trend. Our findings suggest that increasing water stress may slow the rate of global iWUE increase as the climate continues to warm
A PROOF OF THE SOLITON RESOLUTION CONJECTURE FOR THE BENJAMIN-ONO EQUATION
No full textWe give a proof of the soliton resolution conjecture for the Benjamin-Ono equation, namely every solution with sufficiently regular and decaying initial data can be written as a finite sum of soliton solutions with different velocities up to a radiative remainder term in the long-time asymptotics. We provide a detailed correspondence between the spectral theory of the Lax operator associated to the initial data and the different terms of the soliton resolution expansion. The proof is based on a new use of a representation formula of the solution due to the second author, and on a detailed analysis of the distorted Fourier transform associated to the Lax operator
Understanding the influence of ideology on the dynamics of sociotechnical systems through co-design activities: a case study in a cohousing community
No full textInternational audienceThis article concerns the importance of human values in designing and deploying sociotechnical systems. These values relate to what the system delivers versus what users expect regarding equality, democracy, or quality of work. We explore how the value system (ideology) influences stakeholders’ decisions when designing the technical and social dimensions of a system in which they are involved. We focus on the thinking and reasoning processes involved in co-design situations. Through the case of a community system, we closely analyse the verbal interactions during a two-day meeting involving 9 to 12 participants. We illustrate how community ideology plays a central role in reconfiguring the system ‘in action’, highlighting the misunderstandings and conflicts that arise during the design process and the strategies employed by the participants to advance the project. The findings suggest that examining co-design activities can enhance our understanding of ideology’s impact on system design