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Chiral Pt(Me-BPCH): Synthesis and theoretical investigation of parity violation sensitivity
No full textA complex of platinum and the tetra-coordinate chelating ligand, R,R'-6,6'-dimethyl-N,N'-bis(2'-pyridine-carboxamide)-1-cyclohexane (Me-BPCH) is investigated as a potential candidate for measurement of parity violation (PV) in chiral molecules. The synthesis of Pt(Me-BPCH) is presented alongside computational investigation of PV sensitivity in its vibrational spectrum. Pt(Me-BPCH) is compared to other two derivatives of this complex, Au(Me-BPCH) and Pt(CF-BPCH) in terms of their PV response and suitability for measurement. We identify the most promising vibrational transitions based on their enhanced PV effects and practical experimental considerations and analyze the relationship between the vibrational structure and the corresponding PV sensitivity for all three molecules
Coherent Control Over the High-Dimensional Space of the Nuclear Spin of Alkaline-Earth Atoms
No full textInternational audienceWe demonstrate coherent manipulation of the nuclear degrees of freedom of ultracold ground-state strontium-87 atoms, thus providing a toolkit for fully exploiting the corresponding large Hilbert space as a quantum resource and for quantum simulation experiments with s u ( N ) -symmetric matter. By controlling the resonance conditions of Raman transitions with a tensor light shift, we can perform rotations within a restricted Hilbert space of two isolated spin states among the 2 F + 1 = 10 possible states. These manipulations correspond to engineering unitary operations derived from generators of the s u ( N ) algebra beyond what can be done by simple spin precession. We present Ramsey interferometers involving an isolated pair of Zeeman states with no measurable decoherence after 3 s. We also demonstrate that one can harness the large spin degrees of freedom as a qudit resource by implementing two interferometer schemes over four states. The first scheme senses in parallel multiple external fields acting on the atoms, and the second scheme simultaneously measures multiple observables of a collective atomic state—including noncommuting ones. Engineering unitary transformations of the large spin driven by other generators than the usual spin- F representation of the s u ( 2 ) group offers new possibilities from the point of view of quantum metrology and quantum many-body physics, notably for the quantum simulation of large-spin s u ( N ) -symmetric quantum magnetism with fermionic alkaline-earth atoms
Rational approximations to linear subspaces
No full textInternational audienceWe study intrinsic diophantine approximation on Grassmann varieties. Using a new correspondence between the diophantine properties of a linear subspace x in R d and certain diagonal orbits in the space of lattices, we are able to solve some problems suggested by Schmidt in 1967. In particular we obtain a version of Dirichlet's principle in this setting with an optimal exponent. </div
Unified opinion formation analysis in rewriting logic
No full textInternational audienceProcesses of opinion formation rooted in social dynamics can significantly contribute to the polarization of social, political, and democratic interaction. Opinion dynamic models are essential for understanding the impact of specific social factors on the acceptance or rejection of opinions. This extended paper builds upon the conference presentation documented in [1], introducing improvements and new opinion models that explore biases and collective human behaviors. It presents a framework based on concurrent set relations that formalizes, simulates, and analyzes social interaction systems with dynamic opinion models. Within this framework, standard models for social learning are realized as specific instances. Implemented in the Maude system as a fully executable rewrite theory, the framework enables a detailed examination of how agents' opinions can be influenced within a system. The authors report on new formalization of several and existing social learning models, exploring their relationships with different concurrency models. New experimentation involving reachability analysis, probabilistic simulation, and statistical model checking has been conducted. These experiments are crucial for validating significant properties related to dynamic opinion models in Maude, offering new insights into the mechanisms of opinion shaping in social interaction
Innovative methodological and analytical developments in the study of plant-soil fauna interactions: the contribution of metabolomics
No full textInternational audiencePlant–soil interactions are modified by both biotic and abiotic factors, and understanding these dynamics is essential to predict ecosystem responses to climate change. Root exudates play a central role in rhizosphere dynamics through the release of primary and specialized metabolites, which are involved in defense mechanisms, competition, and symbiosis. However, the influence of soil fauna on root exudation remains poorly understood. To date, studying root exudation in soil matrices has been technically challenging, and the most commonly used systems hydroponic or hybrid fail to reproduce realistic interactions with soil fauna.Presently, we investigate how soil fauna, specifically nematodes, modulate the quantity and composition of root exudates in Linum usitatissimum, and how these interactions are further influenced by increased temperature. Using the innovative ECOROOTS system, root exudates are collected in situ using nitrocellulose traps placed at the root apex, allowing for high-resolution metabolomic profiling via GC-HRMS (1-2). Additionally, molecular networks based on GC-HRMS data have been developed to support metabolite annotation. Preliminary results indicate that the presence of nematodes significantly alters the exudation profile of Linum usitatissimum, an effect that is further amplified under a +4◦C.This methodology will be further integrated with HPLC-HRMS analyses, providing a robust multiblock approach for the investigation of root exudation in other plant species with allelopathic potential or agronomic relevance.(1) V. Bohm et al., mai 2025, doi: 10.1016/j.jcoa.2025.100205(2) A. Levasseur et al., juin 2025, doi: 10.1016/j.soilbio.2025.109771
Counteracting the Mechanisms of Heart Failure is the Most Effective Way to Decongest Patients while Improving Outcomes
No full textInternational audienceDiuretic therapy is not associated with improved outcomes in heart failure and may cause significant side effects. Counteracting the core pathophysiological mechanisms of heart failure through neurohormonal blockade while reducing reliance on diuretics is potentially the most effective method of decongestion
Participatory research in the co-production of science and knowledge
No full textWhat is the verdict on participatory research practices ? What are the ethical and institutional issues at stake?The concrete initiatives carried out at IRD are helping to establish a community of practices,define the guaranteesof research integrity and build trust between the researchers and the public involved
Heart failure with preserved ejection fraction: seeking the holy grail of estimating functional cardiometabolic reserve
No full textInternational audienceNo abstract availabl
Le traitement des « troubles du comportement » des adolescents aux urgences hospitalières : impasse ou nouvelles régulations ?
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Prevalence and factors associated with severe illness in West African children under 5 years of age detected with routine pulse oximetry in primary care
No full textInternational audienceBackground The Integrated Management of Childhood Illness (IMCI) guidelines are symptom-based algorithms used to identify critically ill children under five in primary health centres (PHC) in resource-limited countries. Hypoxaemia, a life-threatening event, is clinically underdiagnosed. The Amélioration de l'Identification des détresses Respiratoires de l'Enfant/Improving Identification of Respiratory Distress in Children (AIRE) project implemented the routine use of pulse oximetry (PO) within IMCI consultations to improve the diagnosis and management of severe hypoxaemia (pulse blood oxygen saturation <90%) at PHC level in Burkina Faso, Guinea, Mali and Niger. In this context, we measured the prevalence of severe cases and their associated social and structural factors among outpatients. Methods In 16 AIRE research PHC (4/country), all the children under five attending IMCI consultations, except those aged 2–59 months classified as simple case without cough or breathing difficulties, were eligible for the use of PO and enrolled in a cross-sectional study with parental consent. Severe IMCI+PO cases were IMCI severe cases or those with severe hypoxaemia. Results From June 2021 to June 2022, 968 neonates (0–59 days) and 14 868 children (2–59 months) were included. Prevalence of severe IMCI+PO cases was heterogeneous between countries: 5.0% in Burkina Faso, 6.1% in Niger, 18.9% in Mali and 44.6% in Guinea. Among neonates, 21.9% (95% CI 19.3 to 24.6) were severe cases versus 12.0% (95% CI 11.4 to 12.5) in older children, of which 3.3% versus 0.8%, respectively (p<0.001), had severe hypoxaemia. The adjusted social and structural factors associated with disease severity common to all four countries were as follows: age <2 months or >2 years, IMCI consultation delay >2 days, home to PHC travel time >30 min. Conclusion The prevalence of seriously ill children under five, including severe hypoxaemia, was high in PHC, particularly in neonates. The high between-country heterogeneity may be explained by differences in case definitions (Guinea) and structural factors (accessibility). Improving early access to primary care could be an actionable lever to improve the health of West African children