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Efficient and Scalable Search for Statistics
No full textInternational audienceInformed public debate needs high-quality data. In this context, high-quality statistical data sources are a valuable category of reference information based on which a claim can be checked. To facilitate the work of journalists or other fact-checkers, users’ questions about a specific claim should be automatically answered based on statistical tables. This task is complicated by the large number, size, and variety of statistical datasets.We introduce the statistical table discovery problem (STD, in short), which aims, given a natural language question and a set of statistic datasets (multidimensional tables), to find the tables most relevant for the question. We then describe STAR, an algorithm for solving the STD problem. Unlike existing table discovery (TD) solutions aimed at relational tables, STAR is devised specifically for multidimensional ones. Further, STAR treats the space and time dimensions of statistical datasets separately. We experimentally show that these features, together, make STAR outperform state-of-the-art TD systems adapted to the STD problem, in terms of scalability, search quality, preprocessing and question answering time
Micro-Poro-Mechanical Modeling of The Lung Parenchyma: Theoretical Modeling and Parameters Identification
No full textInternational audienceMicro-poro-mechanical approaches can be employed to simulate the behavior of porous media, such as lung parenchyma, with respect to their microscopic morphological and mechanical features. In this work, we propose a general micromechanical framework to describe the behavior of a porous hyperelastic material in large strains, including surface tension, and adapt its parameters to reproduce lung parenchyma behavior. We illustrate the method on a 2D periodic microstructure. The modeling framework is adaptable to any microstructure and any combination of stress, strain and pressure loadings.The identification of the model parameters in the context of lung parenchyma, based on existing experimental morphological and pressure-volume data, is performed sequentially. 12 parameters related to morphology, alveolar wall constitutive behavior and surface tension are calibrated to reproduce pressure-volume curves in various conditions, for a porosity in the unloaded state set to Φf0 =63%. The calibrated alveolar diameter is Dalv = 54 μm. The identifiability of the Neohookean and Ogden-Ciarlet-Geymonat hyperelastic potential parameters is studied; their values are β1 = 94.3 Pa, β2 = 16.9 Pa, β3 = 619 Pa and α = 3.154. The hysteretic response of lung to pressure is reproduced thanks to the formulation of a surface-dependent surface tension. This work paves the way for a better understanding of the relationship between microscopic features and the macroscopic response of lung, in healthy and pathological conditions. Further experimental investigations could help confirming the ranges of parameters obtained in this study
Interhemispheric and Latitudinal Variability of Ionospheric Disturbances During the 19-20 December 2015 Geomagnetic Storm: Insights from the South American Sector
No full textInternational audienceThis study investigates the response of the South American ionosphere to the December 19-20, 2015, geomagnetic storm using multi-instrument satellite and ground-based data. An interplanetary shock triggered prompt penetration electric fields (PPEFs) during the storm's initial phase, initiating rapid DP2 currents and significant equatorial electrojet (EEJ) fluctuations, particularly in Jicamarca, Peru. Our analysis shows that dayside field-aligned currents (FACs) are the primary drivers of the observed DP2 fluctuations. The South Atlantic Magnetic Anomaly (SAMA) also induced a westward geomagnetic gradient-induced current at the equatorward boundary, which suppressed the EEJ current at São Luiz during the magnetically quiet period. During the storm's main phase, eastward PPEFs enhanced ionospheric irregularities at several Global Positioning Satellite (GPS) stations: Sao Luiz (14.8%), Cuiaba (11.4%), and Jatai (15.5%) in Brazil; Tucuma (33.6%) and Rio Grande (33.2%) in Argentina; and all Peruvian GPS stations (5.8 -57.6%), with Arequipa showing the highest percentage. Conversely, irregularities were inhibited at Eusebio (-31.5%), São José dos Campos (-11.8%), and Campo Grande (-4.8%) in Brazil, and Rosario (-9.4%) and Villegas (-0.8%) in Argentina, relative to a magnetically quiet day, which was attributed to the interplay between westward disturbance dynamo electric fields (DDEF) and PPEF. Joule heating, peaking at 14:35 UT on 20 December drove equatorward disturbance winds that generated the DDEF and modulated irregularities during the recovery phase. Westward DDEF suppressed post-sunset irregularities across most Brazilian and Argentine stations (-50.2% to -10.1%), but slightly enhanced post-midnight ionospheric irregularities at Cuiabá (+4.3%) and Tucuma (+21.1%). All Peruvian stations recorded post-midnight enhancements (+14.8% to +136.7%), with Arequipa showing the highest increase. We quantified the delayed magnetic response of the disturbance dynamo (Ddyn) relative to Joule heating, revealing propagation delays of approximately 6, 8.5, and 8.2 h in Brazil, Argentina, and Peru, respectively. Ddyn exhibited strong spatiotemporal variability, including spatial anomalies associated with the SAMA. The Peruvian sector dominated the Ddyn power (59.0%), followed by Brazil (35.1%) and Argentina (5.9%). Evidence of interhemispheric FAC asymmetry, attributed to seasonal variability, was also observed. These findings significantly advance our understanding of storm-time lowlatitude electrodynamics and their regional variability
A MeerKAT search for persistent radio sources towards twenty-five localised Fast Radio Bursts
No full textInternational audienceThe discovery of persistent radio sources (PRSs) associated with repeating fast radio bursts (FRBs) has shed light on the immediate environments and possible progenitors of these FRBs. The confirmed PRSs may support the theory that FRB progenitors are compact central engines, whilst the non-detections suggest diversity of FRB's local environment. We perform a subarcsecond-resolution MeerKAT search at 1.28 GHz on 25 well-localised FRB positions provided by ASKAP and MeerTRAP. We detect 14 radio sources and provide flux upper limits for 12 non-detections (both these numbers include a source that was detected during two epochs of observation, and not detected during one epoch, adding up to 26). One radio source shows variability as seen in flux variations over three epochs of observation. Archival optical data reveal excesses in the direction of 13 detected radio sources. Similarly for four sources in the X-ray band, with one possibly being a high-energy signature of a radio galaxy core. Since we cannot definitively classify our detected radio sources as PRSs, future high-resolution observations with e-MERLIN will be required to resolve the radio emission and pronounce on the presence of compact PRSs associated with the 14 detected sources presented here
Polynomialization of ordinary differential equations given by straight-line programs
No full textGiven a system of ordinary differential equations represented by a straight-line program, we show how to compute an equivalent ordinary differential system represented by a straight-line program which only uses ring operations. Under mild assumptions, our method essentially runs in linear time
Critical and multicritical Lee-Yang fixed points in the local potential approximation
No full textInternational audienceThe multicritical generalizations of the Lee-Yang universality class arise as renormalization-group fixed points of scalar field theories with complex interaction, , just below their upper critical dimension. It has been recently conjectured that their continuation to two dimensions corresponds to the non-unitary conformal minimal models . Motivated by that, we revisit the functional renormalization group approach to complex -symmetric scalar field theories in the Local Potential Approximation, without or with wavefunction renormalization (LPA and LPA' respectively), aiming to explore the fate of the theories from their upper critical dimension to two dimensions. The fixed points are identified using a perturbative expansion of the functional fixed-point equation near their upper critical dimensions, and they are followed to lower dimensions by numerical integration of the full equation. A peculiar feature of the complex -symmetric potentials is that the fixed points are characterized by real but negative anomalous dimensions , and in low dimension , this can lead to a change of sign of the scaling dimensions , thus requiring a novel analysis of the analytical properties of the functional fixed-point equations. We are able to follow the Lee-Yang universality class () down to two dimensions, and numerically determine the scaling dimension of the fundamental field as a function of . On the other hand, within the LPA', multicritical Lee-Yang fixed points with cannot be continued to due to the existence of unexpected non-perturbative fixed points that annihilate with the fixed points
Fathers have embraced longer and more flexible paternity leave
No full textInternational audienceReformed in 2021, paternity leave in France was extended and made more flexible. The proportion of fathers taking this leave continues to grow, particularly among those that used to claim it least, such as self-employed workers, those on fixed-term contracts, and the least-educated fathers. Fathers’ presence at the birth of their child and beyond is becoming the norm. However, occupational and financial pressures remain an obstacle to the use of paternity leave. Only a minority of fathers take a “solo” paternity leave after the mother’s return to work, but these numbers are increasing.La réforme du congé de paternité en 2021 a allongé sa durée et assoupli ses modalités. La part de pères prenant ce congé continue à augmenter, notamment chez ceux qui y avaient le moins recours comme les indépendants, les salariés en contrat à durée déterminée, les pères moins diplômés. La présence des pères au moment de la naissance se généralise et dure plus longtemps. Cependant, les contraintes professionnelles et financières restent un frein à la prise du congé. Même s’ils restent minoritaires, les pères qui prennent le congé « en solo », alors que la mère a repris le travail, sont de plus en plus nombreux
La biochimie des interactions conservées de la levure à l'homme pour la voie NMD
No full textNonsense-mediated mRNA decay (NMD) is one of the most extensively studied pathways of cytoplasmic mRNA degradation. It plays a critical role in diverse cellular processes by eliminating aberrant transcripts containing premature stop codons and by regulating the stability of physiological mRNAs. NMD factors were initially identified through genetic screens in S. cerevisiae (UPF1, 2, 3) and C. elegans (SMG-1, SMG5-7). Subsequent biochemical studies revealed the composition of NMD complexes and identified additional factors. A major protein hub for NMD is Upf1, an ATP-dependent RNA helicase that is part of two mutually exclusive NMD assemblies, the Upf1-Upf2-Upf3 complex and the Upf1-decapping complex, which contains the decapping enzyme and its co-factors. Here, we discuss recent findings, primarily from budding yeast, on the protein-protein interactions driving NMD complex dynamics and their similarities to human NMD. Together, the N-terminal cysteine and histidine rich (CH) and helicase domains (HD) of Upf1 act as a hub for binding multiple partners. Upf1 is required for binding to NMD substrates and for the initiation of RNA degradation through decapping (yeast) or endonucleolytic hydrolysis (humans). We focus on the interplay between Upf2, Dcp2 and Nmd4 (yeast SMG6), which ensures the mutually exclusive formation of Upf1-bound subcomplexes modulating Upf1's affinity for RNA. Thus, the study of NMD factors interactions in different organisms sheds new light on the remarkable conservation of NMD molecular mechanisms
Search for dark matter produced in association with a Higgs boson decaying to bottom quarks in proton-proton collisions at = 13 TeV
No full textInternational audienceA search for dark matter particles produced in association with a Higgs boson decaying to a bottom quark-antiquark pair in proton-proton collisions at = 13 TeV is presented. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 101 fb. The analysis is performed in exclusive categories targeting both Lorentz-boosted (merged) and resolved b jet pair topologies, covering a wide range of Higgs boson transverse momentum. A statistical combination is made with a previous search using data collected in 2016 and corresponding to an integrated luminosity of 35.9 fb. The observed data agree with the standard model background predictions. Constraints are placed on models predicting new particles or interactions, such as those in the simplified frameworks of baryonic-Z' and 2HDM+a, where the latter is a type-II two-Higgs-doublet model featuring a heavy pseudoscalar with an additional light pseudoscalar. Upper limits at 95% confidence level are set on the production cross section for these models. For the baryonic-Z' model, Z' boson masses below 2.25 TeV are excluded for a dark matter particle candidate mass of 1 GeV. In the 2HDM+a model, heavy pseudoscalar masses between 850 and 1300 GeV are excluded for a light pseudoscalar mass of 350 GeV
Offline Contextual Bandit with Counterfactual Sample Identification
No full textRecsys '25, CONSEQUENCES: Causality, Counterfactuals & Sequential Decision-Making WorkshopIn production systems, contextual bandit approaches often rely on direct reward models that take both action and context as input. However, these models can suffer from confounding, making it difficult to isolate the effect of the action from that of the context. We present Counterfactual Sample Identification, a new approach that re-frames the problem: rather than predicting reward, it learns to recognize which action led to a successful (binary) outcome by com-paring it to a counterfactual action sampled from the logging policy under the same context. The method is theoretically grounded and consistently outperforms direct models in both synthetic experi- ments and real-world deployments