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Nebula: Efficient, Private and Accurate Histogram Estimation
No full textInternational audienceWe present Nebula, a system for differential private histogram estimation of data distributed among clients. Nebula enables clients to locally subsample and encode their data such that an untrusted server learns only data values that meet an aggregation threshold to satisfy differential privacy guarantees. Compared with other private histogram estimation systems, Nebula uniquely achieves all of the following: i) a strict upper bound on privacy leakage; ii) client privacy under realistic trust assumptions; iii) significantly better utility compared to standard local differential privacy systems; and iv) avoiding trusted third-parties, multi-party computation, or trusted hardware. We provide both a formal evaluation of Nebula's privacy, utility and efficiency guarantees, along with an empirical evaluation on three real-world datasets. We demonstrate that clients can encode and upload their data efficiently (only 0.0058 seconds running time and 0.0027 MB data communication) and privately (strong differential privacy guarantees ε = 1). On the United States Census dataset, the Nebula's untrusted aggregation server estimates histograms with above 88% better utility than the existing local deployment of differential privacy. Additionally, we describe a variant that allows clients to submit multi-dimensional data, with similar privacy, utility, and performance. Finally, we provide an open source implementation of Nebula
Sages-femmes et parents en séances de préparation à la naissance et à la parentalité (PNP) : une activité expérientielle pour apprendre et se développer
No full textInternational audienceLes séances de préparation à la naissance et à la parentalité représentent un dispositif d’actes visant le développement des parents dans une relation éducative autonomisante et le transfert des apprentissages du prénatal au postnatal. Cette dimension formative représente un enjeu majeur en santé publique. Depuis 2005, la participation active des parents par le « pratiquer et faire par la mise en œuvre d’un travail corporel » est fortement encouragée. En plaçant le parent-apprenant au centre de l’action pour apprendre par lui-même, quelle analyse de l’activité pouvons-nous envisager ? Quelles compétences sont mobilisées par les parents et les sages-femmes ? L’analyse de notre corpus a permis d’extraire des modalités d’action, révélatrices de quatre types de compétences pour les sages-femmes. Pour les sujets parents, nous avons identifié plusieurs types de connaissances
Guiding the Algorithm: Harnessing artificial intelligence to nurture SMEs management control systems
No full textInternational audienceThe diffusion of artificial intelligence (AI) amongst organizations is profoundly revolutionizing business processes, such management control (MC) practices. However, the existing literature reveals a significant gap in understanding the contribution of AI-empowered tools to management control systems (MCSs), particularly within small and medium enterprises (SMEs), where these systems are often rudimental, informal, subjective, and short-period-oriented. To address this gap, the authors employed a mixed-methods approach, featuring an open-coding and thematic analysis of AI-generated answers to MC questions related the analysis of liquidity and profitability ratios from 37 Italian SMEs, as well as a qualitative investigation, with in-depth interviews with 15 respondents, to highlight their perceptions. Our investigation is informed by the social construction of technology theory, to explore the relevant social groups, interpretative flexibility, technological frames and patterns of closure related to AI-empowered tools and their contribution to SMEs' MCSs. We connect our findings to two frames, which highlight, on the one hand the positive contribution of such tools to SMEs' MCSs through accurate and comprehensive responses; on the other hand, a negative frame highlights concerns related to inconsistency and verbosity of the answers, which may affect trust and usability. This manuscript aims to provide an overview of the possible contribution of AI-empowered tools to SMEs' MCSs. Both scholars and practitioners can benefit from the theoretical and practical implications provided, which complements the limited number of studies in the field. Future research avenues are discussed
Channel deformations during elastocapillary spreading of gaseous embolisms in biomimetic leaves
No full textInternational audienceThe nucleation and/or spreading of bubbles in water under tension (due to water evaporation) can be problematic for most plants along the ascending sap network—from roots to leaves—called xylem. Due to global warming, trees facing drought conditions are particularly threatened by the formation of such embolisms, which hinders sap flow and can ultimately be fatal. Polydimethylsiloxane (PDMS)-based biomimetic leaves simulating evapotranspiration have demonstrated that, in a linear configuration, the existence of a slender constriction in the channel allows for the creation of intermittent embolism propagation (as an interaction between the elasticity of the biomimetic leaf and the capillary forces at the air/water interfaces) (Keiser et al . 2022 J. Fluid Mech. 948 , A52 (doi: 10.1017/jfm.2022.733 ); Keiser et al . 2024 J. R. Soc. Interface 21 , 20240103 (doi: 10.1098/rsif.2024.0103 )). Here, we use analogue PDMS-based biomimetic leaves in one dimension and two dimensions. To better explore the embolism spreading mechanism, we add to the setup an additional technique, allowing to measure directly the microchannel’s ceiling deformation versus time, which corresponds to the pressure variations. We present here such a method that allows one to have quantitative insights into the dynamics of embolism spreading. The coupling between channel deformations and the Laplace pressure threshold explains the observed elastocapillary dynamics
The subjunctive as a linguistic expression of the core of emotions: A contribution to Wiltschko’s (2024) view on constructed emotions
No full textInternational audienceThis short essay discusses the syntactic implications of Wiltschko’s (2024) proposal concerning the structure of emotions. Based on a generative analysis of embedded subjunctive clauses cross-linguistically, it argues that the emotive component associated with the subjunctive mood originates in a sub-component of the predicates licensing embedded subjunctives. This emotive component is interpreted as an attitude of desire, with respect to the situation described by the embedded clause. More specifically we argue that the relevant predicates are decomposed into a set of hierarchically organised functional projections, the highest one headed by a bouletic operator—syntactically realised as a [BOUL] feature. We contend that this feature is responsible both for the interpretation of the external argument as the bearer of an emotion and for the syntactic licensing of the subjunctive mood. That the expression of emotions is syntactically encoded into complex structures may shed light on the structure of both the linguistic and psychological structures of emotions
Boosting classical and quantum nonlinear processes in ultrathin van der Waals materials
No full textInternational audienceUnderstanding and controlling nonlinear processes is crucial for engineering light-matter interaction and generating non-classical light. A significant challenge in ultra-thin nonlinear materials is the marked diminution of the nonlinear conversion efficiency due to the reduced light-matter interaction length and, in many cases, the centrosymmetric crystalline structures. Here we relax these limitations and report a giant boost of classical and quantum nonlinear processes in ultrathin van der Waals materials. Specifically, with a metal-nonlinear material heterostructure we enhance classical second-harmonic generation in h-BN flakes by two orders of magnitude. Moreover, we have engineered a metal-SiO2-nonlinear material heterostructure resulting in a remarkable two orders of magnitude augmentation of the quantum spontaneous parametric down-conversion (SPDC) in NbOCl2 flakes. Notably, we demonstrate SPDC in a 16 nm-thick NbOCl2 flake integrated into the proposed structure. These findings simplify on-chip quantum state engineering and accelerate the use of van der Waals materials in nonlinear optoelectronics
Effect of oxygen content on p-type electrical conductivity in β-Ga<sub>2</sub>O<sub>3</sub> films
No full textInternational audienceGa2O3 is a promising ultrawide bandgap semiconductor, but achieving reliable p-type conductivity remains a challenge, especially due to the scarcity of high-quality homoepitaxial p-type β-Ga2O3 layers. In this study, we investigate β-Ga2O3 thin films homoepitaxially grown on (01) Fe doped β-Ga2O3 substrates via metal organic chemical vapor deposition under different oxygen-to-gallium (O/Ga) ratios. We examine the effect of oxygen content on the structural, electrical, and optical properties of thin films. The layer grown under oxygen-rich conditions (O/Ga = 6400) exhibited an enhanced crystallinity of the dominant (01) orientation as indicated by a low full-width at half maximum (FWHM) of 72 arcsec in the X-ray diffraction rocking curve, a suppressed oxygen vacancy signal in X-ray photoelectron spectroscopy, and a two order of magnitude increase in hole concentration (p = 4.5 × 1015cm-3 vs. 4.6 × 1013 cm-3 at 570 K), associated with a shallow acceptor level with an activation energy of 0.21 eV, likely due to VGa- - Vo++ complex-like defect. In addition, both films exhibit hole mobility μ H > 30 cm 2 /V⋅s over the measurement temperature range. These findings suggest that oxygen-rich growth conditions enhance both the crystallinity and native hole conductivity of β-Ga2O3, offering a promising route toward achieving controlled p-type behavior in this material
Chimiothérapie intra artérielle hépatique séquentielle sans chambre implantée chez des patients porteurs de métastases de cancer colorectal
No full textObjectif : évaluer la faisabilité et la sécurité des cathéters temporaires par rapport aux cathéters implantés pour la chimiothérapie intra-artérielle hépatique (CIAH) chez les patients atteints de métastases hépatiques de cancers colorectaux.Matériels et méthodes : cette étude observationnelle rétrospective monocentrique, menée en France entre janvier 2010 et juillet 2024, a inclus les patients traités par CIAH après validation en réunion multidisciplinaire. Le traitement a été réalisé via cathéter temporaire ou implanté. Le critère principal, le succès technique, correspondait à une procédure complète sans interruption ni reprogrammation. Les complications liées à la procédure, les effets systémiques, les doses d’irradiation Produit Dose Surface (PDS) et les données cliniques ont été analysés. Une marge de non-infériorité de 2,5 % a été retenue.Résultats : 81 patients (âge médian : 63 ans ; 56 % hommes) ont été inclus. Un cathéter temporaire a été utilisé dans 69 % des cas, implanté dans 27 %, et les deux dans 3,7 %. Le taux de succès technique était de 95 %, sans différence significative entre cathéters temporaires (96 %) et implantés (94 %, p = 0,022). Les cas de migration ou d’occlusion étaient plus fréquents avec les cathéters implantés (5,4 % vs 0,9 %, p = 0,013). Les complications procédurales (3,9 %) et systémiques (53 %) n’étaient pas significativement différentes entre les groupes. La PDS était plus élevée avec les cathéters temporaires (13 ± 14 vs 6 ± 10 Gy·cm², p < 0,001).Conclusion : les cathéters temporaires apparaissent comme une alternative sûre aux cathéters implantés dans le cadre de la CIAH, en particulier dans le contexte actuel de pénurie
Un fort séisme récent dans les Alpes du Sud ?
No full textNational audienceL’analyse d’images aériennes a mis en évidence un escarpement continu sur environ 3 km de long au col de Lombarde (proche de la station d’Isola 2000 dans les Alpes du Sud). Dans le cadre de l’action FACT (Faille Active en France,Epos-France), 2 tranchées paléosismologiques ont été réalisées le long de l’escarpement et sont en cours d’analyse. Les premiers résultats laissent supposer un paléoséisme avec une magnitude de l’ordre de 6,5-7 dans les dernières dizaines de milliers d’années
