"La contribution du banquier au droit de l’ingénierie sociétaire"

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Hybrid antioxidant based on exfoliated layered double hydroxides nanosheets with improved thermal stabilizing effects for polypropylene

International audienceAn antioxidant (AO) agent, 3-(3,5-ditertbutyl-4-hydroxyphenyl) propionate anions (DBHP), intercalated between layered double hydroxides (DBHP-LDH) was prepared by coprecipitation method and then a part was delaminated in toluene to form exfoliated DBHP-LDH nanosheets. Both types of DBHP-LDH compositions, powder and exfoliated nanosheets were characterized by XRD, SEM and TEM, and subsequently incorporated into polypropylene (PP) as AO filler to improve the thermal stability of PP. The addition of DBHP-LDH affected the crystallization and melting behaviour as well as transmittance of PP, giving rise to its crystallinity improved but its transparency reduced. It was found that by incorporating either DBHP-LDH powder or exfoliated DBHP-LDH nanosheets the thermal decomposition temperatures and thermal aging resistance of PP were enhanced. Interestingly, between the two hybrid systems, it is however the exfoliated DBHP-LDH nanosheets that showed a better stabilizing effect for PP. This is attributed to the better dispersion regarding the exfoliated DBHP-LDH nanosheets, thus providing a more efficient radical scavenging capability. Even with its pronounced interface between PP chains and highly exposed nanosheets, about 30 % of DBHP was released from the exfoliated DBHP-LDH/PP compared to about 20 % DBHP migrated out of the conventional DBHP-LDH/PP films after 132 h test. This shows that the organic AO agent is well tethered to hydroxyl-bearing LDH nanosheets, thus opening new route to design functionalized filler for polymer from exfoliated LDH hybrid layers

First evidence of the Bs0→K−π+γB_s^0\rightarrow K^-π^+γ decay

International audienceThe first search for the $B_s^0\rightarrow K^-π^+γ$ decay in the range $796<m(K^-π^+)<1800\,\text{MeV/}c^2$ is performed using data from proton-proton collisions collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb$^{-1}$. The photons are reconstructed through their conversion into an electron-positron pair, which significantly improves the mass resolution of the reconstructed decays with respect to decays with an unconverted photon. A signal excess with a significance of 3.5 standard deviations is measured, constituting the first experimental evidence for this decay. In the range $796<m(K^-π^+)<996\,\text{MeV/}c^2$, the ratio ${\cal R}$ between the branching fractions of the signal decay and the favoured $\kern 0.18em\overline{\kern -0.18em B}{}^0\rightarrow K^- π^+γ$ decay is measured to be ${\cal R} = (3.7\pm1.2\pm0.4)\times10^{-2}$ where the first uncertainty is statistical and the second is systematic. This measurement is consistent with the value predicted in the Standard Model. In the range $996<m(K^-π^+)<1800\,\text{MeV/}c^2$, the ratio ${\cal R} = (0.2\pm2.7\pm1.3)\times10^{-2}$ is measured

Differentiable Surrogate for Detector Simulation and Design with Diffusion Models

International audienceIn this work, we present a conditional denoising-diffusion surrogate for electromagnetic calorimeter showers that is trained to generate high-fidelity energy-deposition maps conditioned on key detector and beam parameters. The model employs efficient inference using Denoising Diffusion Implicit Model sampling and is pre-trained on GEANT4 simulations before being adapted to a new calorimeter geometry through Low-Rank Adaptation, requiring only a small post-training dataset. We evaluate physically meaningful observables, including total deposited energy, energy-weighted radius, and shower dispersion, obtaining relative root mean square error values below 2% for representative high-energy cases. This is in line with state-of-the-art calorimeter surrogates which report comparable fidelity on high-level observables. Furthermore, we compare gradients of a reconstruction-based utility function with respect to design parameters between the surrogate and finite-difference references. The diffusion surrogate reproduces the qualitative structure and directional trends of the true utility landscape, providing usable sensitivities for gradient-based optimization. These results show that diffusion-based surrogates can accelerate simulation-driven detector design while enabling differentiable, gradient-informed analysis

The BIOMASP+ project on biosphere-atmosphere exchanges and their role in air pollution in the subtropical megacity of São Paulo: motivations, methods and preliminary observations

International audienceAir pollution, especially in urban areas, is the result of a complex mixture of natural and anthropogenic emissions and their atmospheric processing. It causes millions of premature deaths worldwide and affects plant metabolism, which in turn alters the emissions of Biogenic Volatile Organic Compound (BVOCs) by plants. By taking the subtropical Metropolitan Area of São Paulo (MASP) as a natural laboratory, the BIOMASP+ project (BIOsphere-atmosphere interactions in the Metropolitan Area of São Paulo - plus) a ims to evaluate the interplay between the biosphere and secondary pollution (ozone and SOA formation and aging). The Brazilian Atlantic Forest (Mata Atlântica) is the target ecosystem as the fifth biodiversity hotspot in the world. Here we present the scientific motivations of the project, its methodology and the preliminary observations from the Special Observation Periods of year 2023 (SOP1, 2, 3 and 4). BIOMASP+ is (i) integrative, by combining in-situ/remote/laboratory observations andmodeling, (ii) multidisciplinary, addressing micrometeorology, urban climate, atmospheric chemistry and biology. The project involves multiple nested scales: from leaf to above-canopy levels, from very short time (microseconds) to multi-year scale, from few millimeters (turbulence scale) to synoptic scale. In particular, the experimental effort relies on the implementation of two contrasting supersites (primary forest and urban forest) with a 30-m and 20-m flux towers, respectively, and a variety of state-of-the-art instruments. Ambient observations and the quantification of BVOC emissions have highlighted the complex interactions between meteorology, atmospheric composition of pollution, biogenic emissions of representative remnants of the Atlantic Forest and anthropogenic emissions

Lire le sol en archéologie : pratiques de terrain et regards croisés

International audienceActes d'un colloque international visant à promouvoir la lecture interdisciplinaire du sol en archéologie sur le terrain, en s’appuyant en particulier sur l’apport des sciences de la Terre. Il s’agissait de faire le lien entre les choix effectués sur le terrain et les étapes qui en résultent (analyses, interprétations…), de favoriser la constitution de référentiels, de guides de bonnes pratiques et de sensibiliser à la reconnaissance des traits pédo-sédimentaires. Le cadre thématique du colloque n’impliquait pas de limite chronologique ou géographique. Toute approche sur des contextes archéologiques pouvait être retenue dès lors qu’il s’agissait de mettre en commun la compréhension du passé, l’étude des occupations, des activités humaines, de l’environnement et des horizons naturels ou anthropisés, dans le dialogue nécessaire entre archéologie et sciences environnementales. Quelles perspectives peuvent offrir l’analyse et l’interprétation des structures et des couches lorsqu’elles sont prises en compte dès les premières observations de terrain ? Comment faciliter cette démarche, rendre cette approche plus efficiente et fluide entre les différents acteurs ? Afin d’optimiser l’étude des sites tout en améliorant leur compréhension, il fallait également entamer une réflexion sur l’utilité de protocoles adaptés et d’outils d’aide à la décision qui peuvent varier de l’échelle intra site à l’échelle territoriale. Tous les acteurs impliqués sur le terrain étaient donc concernés par les échanges de cette rencontre

Marcela de Juan 黄玛赛: A Eurasian Woman’s Perspective on 20th Century China

International audienceMarcela de Juan, whose Chinese name is Huang Masai 黄玛赛, was born in Havana in 1905 to a Chinese father and a Belgian mother. She first lived in Madrid until the age of eight, and then in Beijing until she was twenty-three. She eventually returned to Madrid, where she pursued a career as a translator and dedicated her life to bringing Chinese literature and culture to the Spanish public.In 1977, she published her memoirs, La China que ayer viví y la China que hoy entreví, which reflect on her dual experience of Beijing – first during her childhood and adolescence, and then, on her reunion with China forty-seven years later. This work is doubly comparative, as it contrasts not only two cultures, by bringing Spanish and Chinese customs into dialogue, but also two visions of China, each corresponding to pivotal moments, such as the birth of the Chinese republic or the aftermath of the Cultural Revolution. Although this autobiography was republished in 2021, it remains neglected in the field of research. The aim of this essay is to explore Marcela de Juan’s unique vision of a constantly evolving China, which she sought to bring to the attention of the Spanish public. Spanning the 20th century, Marcela de Juan offers a privileged perspective on China’s political history and daily life, shaped by her dual Spanish and Chinese identity. Furthermore, her autobiography gives a voice to Eurasian women, bearing witness for the first time to anti-Eurasian racism in Spain. To this end, she offers a translinguistic and transcultural style of writing, which transcends boundaries and interweaves Chinese into the Spanish language. This essay therefore analyzes the Sino-Hispanic synergies in Marcela de Juan’s autobiographical work, highlighting her role as a cultural go-between from East to West

Novel multi-level optimization-driven 2D/3D matching for reconstructing 3D fetal postures and motion from childbirth MRI during vaginal delivery

International audienceBACKGROUND AND OBJECTIVE: The description of 3D fetal postures and movements during vaginal delivery is fundamental for a better understanding of the physiological delivery and the prediction of potential complications and related preventive actions. Recently, 2D dynamic MRI has been developed to characterize in vivo childbirth. However, only 2D information is available. The objective of the present study was to reconstruct the 3D fetal postures and movements from 2D dynamic MRI during vaginal delivery. METHODS: A multi-level optimization-driven 2D/3D matching procedure was developed and evaluated. Manual segmentation from 2D dynamic MRI was performed. A 3D generic fetal template model was used to match each segmented MRI slice. Fetal postures and associated motion trajectories were extracted and evaluated. RESULTS: Consistent results were obtained between the MRI images, segmented slices, and reconstructed 3D fetal postures. A maximum 36.20-degree head-neck extension angle was estimated. A range of torso-neck angles from 1.04 to -16.07 degrees was estimated during the vaginal delivery. CONCLUSIONS: We proposed a proof-of-concept study of a multi-level optimization-driven 2D/3D matching scheme to reconstruct 3D fetal postures and associated kinematic patterns from dynamic MRI data during vaginal delivery simulation. It is expected that this novel dataset will make a potential contribution to the future model development and evaluation of the childbirth process

Psychoactive substances in a general forensic autopsy population: prevalence and associations with cause and manner of death

International audienceThis study investigated the prevalence of opioid-related deaths within a general forensic population. Conducted as a prospective, single-center, observational study, it included all subjects autopsied in forensic medicine in the Auvergne region (France). The primary objective was to assess the prevalence of opioid-related deaths in forensic cases, with secondary objectives including evaluating the prevalence of non-opioid psychoactive substances, screening blood alcohol levels, and profiling victims.Among 422 subjects who died from unnatural causes, the leading causes of death were suicide (51.7%) and accidents (39.8%). Opioids were detected in 24.2% of individuals, but directly involved in only 17.6% of those cases. Substances, including alcohol, were found in more than two-thirds of deaths (71.2%). Three distinct victim profiles were identified: middle-aged and elderly males dying by violent suicide; young males dying by fatal traffic accidents, often under the influence of alcohol and drugs of abuse; and young males dying by homicides, frequently under the influence of alcohol, opioids and toxic or lethal drugs.The study provides data on the prevalence and role of opioids, alcohol, and non-opioid psychoactive substances in forensic deaths. While opioids were directly implicated in a limited number of cases, the study highlights the significant presence of alcohol and other non-opioid psychoactive substances in unnatural deaths. These findings, suggest that further research with a larger study area and more cases would be beneficial