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Search for heavy neutral leptons in B-meson decays
No full textInternational audienceA search for long-lived heavy neutral leptons produced in B-meson decays and decaying to a final state is performed with data collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of . The results are interpreted in both lepton-number-conserving and lepton-number-violating scenarios. No significant excess is observed. Constraints are placed on the squared mixing element to the active muon neutrino, under the assumption that couplings to other lepton flavours are negligible, in the mass range of - GeV
EEG theta dynamics for error processing during online movement control
No full textInternational audienceTo ensure optimal visuomotor feedback control during manual tracking, the brain must continuously monitor the error between the hand and the target. Modulations in the theta band (3-8 Hz) are related to error processing, but this has been mainly shown in cognitive control contexts. Hence, their relationship with hand-target errors during online control remains unclear. Here we assessed the impact of motor error processing on EEG theta-band activity in 29 healthy participants while they performed continuous tracking of a moving target with their dominant (right) hand. Two conditions were used to manipulate error processing demands: 1) in the Repeated condition, the same target trajectory was presented 80 times, allowing participants to implicitly learn the pattern and reduce tracking errors; 2) in the Random condition, 80 different trajectories were used, inducing persistent high tracking errors. Behavioral analyses confirmed that tracking errors were significantly higher in the Random than in the Repeated condition. Importantly, EEG theta power was also significantly higher in the Random condition, with a peak difference occurring at electrodes overlaying the left sensorimotor regions. This effect was selective to theta activity, as there was no modulation in alpha-(8-12 Hz) and beta-band (15-30 Hz) activity. Overall, this study extends the role of theta oscillations to online error processing in the context of motor control. It is possible that theta modulations reflected cortical activity mediating the communication and integration of information within sensorimotor circuits including the motor, premotor and parietal cortex, which are known to mediate online movement control. Highlights • Theta power increased with tracking error demands over contralateral sensorimotor regions• No differences in parieto-occipital alpha or sensorimotor beta across conditions• Suggests parieto-frontal sensorimotor integration for online motor error correction</div
Early blood-material interfacial events and capillary transport on nanoparticle-modified nanofibers
No full textInternational audienceElectrospun poly(ϵ-caprolactone) (PCL)nanobrous mats are widely considered for blood-contacting wound dressings and small-diameter vascular applications; however, their intrinsic hydrophobicity limits rapid wetting and controlled interaction with blood. In this work, we modulate the interfacial response of PCL nanobers by incorporating oxideshelled silicon nanoparticles (SiNPs) synthesized by pulsed laser ablation in liquid, a ligand-free approach that avoids organic stabilizers and preserves surface reactivity. Two composite architectures were designed: SiNPs embedded within the ber bulk (PAC-1, -4, -16) and SiNPs preferentially exposed at the ber surface (SPAC-1, -4, -16), with systematically increasing nanoparticle loadings. Structural characterization conrmed the retention of a homogeneous brous morphology and the targeted nanoparticle distribution. The dynamic interaction with whole blood was quantied using time-resolved contact-angle measurements, complemented by top-view optical microscopy and three-dimensional prolometry of dried droplets. Pristine PCL remained strongly hydrophobic, exhibiting a high apparent contact angle that decreased only marginally over time (≈110° to ≈100° over 20 min), whereas a hydrophilic PCL functionalized with APTES showed rapid spreading. Incorporation of SiNPs within the ber volume led to only a moderate enhancement of wettability (final angles ≈80-90°), and dried droplets retained compact morphologies with limited spreading. In contrast, surface-decorated mats displayed a sharp, concentration-dependent transition toward highly wettable behavior: for SPAC-16, the contact angle fell below 20°, droplet proles became markedly attened, and microscopy revealed extended plasma-rich regions surrounding a red-cell-rich core, indicative of pronounced phase separation within the nanobrous network. Consistently, gravimetric measurements showed substantial increases in both water uptake (from ≈400% for PCL to > 700% for SPAC-16) and blood uptake (up to ≈1200% for PAC-16 and ≈1050% for SPAC-16).Overall, these results establish laser-synthesized SiNPs as an effective and chemically simple strategy to control blood wetting, imbibition, and phase separation in electrospun PCL nanofibers. Importantly, nanoparticle localization - within the fiber bulk or at the fiber surface - governs distinct regimes of interfacial behavior. This work provides mechanistic insight into early blood-material interactions on nanofibrous substrates and offers clear design guidelines for tailoring fluid management and hemocompatibility in advanced wound dressing and blood-contacting biomaterials
An effective -Szekeres modelling of the local Universe with Cosmicflows-4
No full textInternational audienceWe develop an effective description of the local cosmic environment, namely, for redshift , to quantify the bias induced by local structure on cosmological observables. Our approach models the metric of the nearby Universe as a superposition of multi-structured -Szekeres patches, calibrated against the HAMLET peculiar velocity and density field reconstructions of Cosmicflows-4. From this framework we compute the fully inhomogeneous and anisotropic quasilocal expansion field predicted by our model, and use it to assess the impact of local structure on estimates of . For this purpose we analyse low-redshift Type Ia supernovae from the Pantheon+ catalogue. We find that accounting for the local structure increases the Hubble tension, yielding a shift in the best-fit value of the Hubble constant of order
Side effects of Covid vaccines: the construction of a media-political taboo
No full textInternational audienceThe issue of the adverse effects of anti-Covid vaccines is so much a subject of political and media denial that it has become a veritable taboo. The chronology shows that there was first a phase of uncertainty (first part of 2021) during which the government's main concern was to cover up the "AstraZeneca affair" and pave the way for mRNA vaccines. Then, as the summer of 2021 approached, the government's desire to vaccinate the entire population and its vote to make vaccination compulsory on pain of social exclusion meant that debate and questioning disappeared in favour of a single discourse touting the "scientifically proven" efficacy and safety of mRNA vaccines and demonising all criticism through the infamous figure of the "anti-vax". The article recounts and analyses this media-political construct, highlighting the complicity of the political authorities with the medical profession and the lack of independence of the public "Authority for Health" agency (Haute Autorité de Santé). It also notes that the doctors promoted as the best 'experts' by the government, and who were omnipresent in the media, hadn't in fact a good command of the scientific information available. Lastly, the article questions the vaccine ideology that has prevailed in France since the early days of the Third Republic, which divides the world into two enemy camps (pro-and anti-vax), moralizes and politicizes vaccination, lumps very different pharmaceutical products together in the same magic word, makes it impossible to calmly assess the benefit-risk balance and considers the question of adverse effects as a fundamentally insignificant issue
Contacts et conflits en Méditerranée (VIe-XIIIe siècle) ; Société, Église et pouvoir politique dans l'Occident médiéval (XIe-XVe siècle)
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Femtosecond Laser Irradiation of Ge-Rich Ge-Sb-Te in Thin Films and Multilayer Structures for Phase-Change Memory
No full textInternational audienceThis study demonstrates that femtosecond laser pulses can efficiently induce amorphization in Ge-rich Ge-Sb-Te (GGST) thin films and GST/GGST multilayer structures. Using cross-sectional scanning transmission electron microscopy (STEM), we examined the structural evolution of undoped and compositionally stabilized GGST films under different femtosecond laser fluences. In both type of samples, a single laser pulse triggered significant structural transformations, including grain dissolution, lattice disorder, and the formation of an amorphous matrix. Two distinct transformation mechanisms were identified: thermal melting followed by rapid quenching and non-thermal bond destabilization via electronic excitation. These findings are supported by high-resolution STEM imaging, SAED patterns, and elemental mapping. Furthermore, successful amorphization was achieved in complex multi-layered architectures composed of alternating GST and GGST layers, underscoring the applicability of femtosecond laser-induced amorphization in advanced phase-change memory (PCM) structures. These results validate the feasibility of ultrafast optical amorphization in GGST single layers and GST/GGST multilayer structures, and provide critical insights for the rational design of next-generation laser-programmable phase-change materials for practical memory device applications
Bridging Design Science research and formal design theories: leveraging C-K theory for impactful research
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Exploring the science of radon adsorption: Materials, methodologies, and emerging directions
No full textInternational audienceRadon, a radioactive noble gas, poses significant health risks due to its link to lung cancer and presents a major challenge in low-background physics experiments, where its decay products contribute to background noise. Developing efficient adsorbent materials for radon mitigation is therefore crucial for both environmental safety and scientific research. However, designing effective radon adsorbents remains challenging due to the low concentration of the gas, its inert nature, and associated health risks. This review provides a comprehensive analysis of radon adsorption on porous materials, with a focus on experimental methodologies, structure-property relationships, and emerging trends in material design. We highlight key material classes, including activated carbons, zeolites, metal-organic frameworks, and other carbon-based adsorbents, evaluating their adsorption performance and practical considerations. Additionally, we explore future directions in radon adsorbent development, discuss improved experimental approaches, and examine insights from xenon adsorption studies as a predictive tool for radon capture. By consolidating current knowledge and identifying critical gaps, this review aims to guide the design of next-generation materials for efficient radon mitigation in environmental, industrial, and scientific applications
The effect of articulatory rehearsal on dual-retrieval processes in semantically related list recall: A comparison between 8- and 10-year-old children and young adults
No full textInternational audienceWhen asked to remember a list of items for later testing, we often repeat earlier items to ourselves as later items are presented. This process, called “rehearsal,” develops during childhood. The present study examined the role of rehearsal in recalling lists of semantically related words and used the dual-retrieval model to pinpoint the retrieval processes modified by rehearsal in children and adults. Thirty-one children (Mage = 8.8 years, SD = 0.5, 12 females and 19 males) and 29 adults (Mage = 20.5 years, SD = 2.7, 23 females and 6 males) performed a complex span task consisting of maintaining words to be recalled later in immediate and delayed tests, while performing a concurrent task. The difficulty of the task was adjusted according to each participant’s abilities. Participants performed the task either silently, which allowed them to use rehearsal, or under articulatory suppression, which reduced rehearsal opportunities. The results showed that, although adults had a higher rate of correct recall, children benefited from rehearsal opportunities for both immediate and delayed correct recall. There were also fewer semantic errors in both age groups when rehearsal could be used. The dual-retrieval model revealed that rehearsal fosters direct access to verbatim memory and reconstruction based on gist memory. Finally, the difference in correct recall and direct access between the two age groups decreased when rehearsal could be used. These findings suggest that, although rehearsal is more effective for adults, children benefit more from it for correct recall and direct access to verbatim traces