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The role of size in the multiple scattering correction C for dual-spot aethalometer: a field and laboratory investigation
No full textInternational audienceAbstract. The dual-spot aethalometer AE33 is a widely used instrument for measuring the aerosol absorption coefficient, but the accuracy of its measurements is heavily dependent on the multiple scattering correction factor (C), which compensates for multiple scattering effects in the filter matrix. Despite its widespread use, several aspects influencing the variability of C, particularly those related to aerosol microphysical properties, are still not fully constrained. In this work, we explore the variability of C for the AE33 in a wide range of conditions and aerosol properties by combining chamber experiments with freshly emitted laboratory-generated soot and ambient data from a mountaintop site in Italy (Monte Cimone, CMN). The C factor is derived by comparison with independent filter-based instruments such as the MAAP (Multi-Angle Absorption Photometer) and MWAA (Multi-Wavelength Absorption Analyzer) at CMN and the extinction-minus-scattering (EMS) approach in chamber experiments. The mean C value at a wavelength of 637 nm derived at CMN is 2.35 with a standard deviation of 0.58, while the average values obtained in chamber experiments in different conditions range from 2.89 ± 0.03 to 3.9 ± 0.06. The variability of C at CMN appears to be primarily influenced by the signal-to-noise ratio of the instruments, especially during the colder months when absorption coefficient values fall below 1 Mm−1. In contrast, in the chamber experiments, the variability is mainly driven by particle properties. The C value at 637 nm, derived from measurements at CMN, increases with increasing single scattering albedo (SSA), particularly for SSA values above 0.94, while showing no statistically significant spectral variability. Both ambient and chamber experiments highlight the dependence of the C factor on particle size, with C increasing as particle diameter decreases below 200 nm. This size dependence is relatively small (within 25 %) under ambient conditions dominated by mostly scattering aerosols, but it leads to changes greater than 60 % for highly absorbing soot particles. These results are relevant for improving the accuracy and comparability of aerosol absorption measurements performed by aethalometers, particularly within monitoring networks. The observed dependence of C on particle size suggests that differences between urban and remote sites, or between periods dominated by nucleation versus coarse-mode particles (e.g., dust), may contribute to the variability reported across locations. Understanding these dependencies is essential for refining correction approaches and reducing inter-site discrepancies in network datasets
Doravirine versus dolutegravir-based regimen in antiretroviral treatment-naive people living with HIV-1 (ANRS0392s ELDORADO): protocol for an international, open-label, randomised, non-inferiority, phase III trial
No full textInternational audienceIntroduction: Increasing evidence suggests that dolutegravir (DTG), endorsed by the WHO since 2018 for first-line antiretroviral therapy (ART), is associated with significant weight gain and potentially also with cardiometabolic disorders. In an effort to expand therapeutic options for people living with HIV (PLHIV), the EvaLuating the non-inferiority of DORAvirine vs DOlutegravir trial aims to compare the virologic efficacy of doravirine (DOR) and DTG-based regimens and to assess their safety, including a focus on cardiometabolic effects.Methods and analysis: This is an international, phase III, multicentre, open-label, non-inferiority, randomised trial that will enrol 610 ART-naïve PLHIV (HIV RNA≥1000 copies/mL at screening) across six countries (Brazil, Cameroon, France, Côte d'Ivoire, Mozambique and Thailand) spanning four continents. Key inclusion criteria include age ≥18 years, confirmed HIV-1 infection with plasma RNA levels ≥1000 copies/mL, indication for ART initiation and no prior ART exposure. Participants will be randomised in a 1:1 ratio to receive either DOR 100 mg once daily in combination with tenofovir disoproxil fumarate (TDF) (300 mg daily) plus lamivudine (3TC) (300 mg daily) or DTG (50 mg daily) in combination with TDF (300 mg once daily) plus either emtricitabine (FTC) (200 mg daily) or 3TC (300 mg daily). Randomisation will be stratified by screening HIV-1 RNA load (≤100 000 or >100 000 copies/mL) and by country. The primary outcome is virological efficacy, defined as the proportion of participants achieving HIV-1 RNA <50 copies/mL at week 48 on the assigned treatment (FDA Snapshot algorithm). Secondary outcomes include cardiometabolic safety endpoints (ie, weight gain, insulin resistance, hypertension, diabetes, waist and hip circumferences, waist-to-hip ratio, fasting glycaemia, insulin and fasting serum lipids), along with mental health, quality of life, virological and immunological parameters. Final data collection is expected by July 2028.Ethics and dissemination: Primary outcome results (week 48) are expected in early 2028. The project was submitted to and approved by national ethics committees and pharmaceutical regulatory authorities in all participating countries: Brazil (CEP INI FIOCRUZ (21.040-900)/CEP HGNI (26.030-380)); Cameroon (CNERSH (2024/09/1717/CE/CNERSH/SP)/Ministry of Public Health (D30-1464/AAR/MINSANTE/SG/DROS/CRC); Côte d'Ivoire: (CNESVS (0018224/MSHPCMU/CNESVS-km)/AIRP (1329/AIRP/DISMP/Om/kbaag); France (CTIS CPP/ANSM (2023-508626-10-00)); Mozambique (CNBS (20/CNBS/25)/ANARME (4635/380/ANARME)); Thailand: (IHRP (08/1944)/Thai FDA: ongoing on 19 January 2026). The trial received authorisation from the French National Commission for Data Protection and Liberties (CNIL) under approval number 924 302. Written informed consent is obtained from all participants prior to any study-specific procedures and trial enrolment, in accordance with the Declaration of Helsinki and applicable national regulations. Study findings will be disseminated through publication in peer-reviewed journals and presentations at national and international scientific conferences. Results will also be communicated to policymakers, healthcare professionals, community stakeholders and study participants through appropriate dissemination activities, including policy briefs, stakeholder meetings and lay summaries on dedicated and easily accessible platforms
Rethinking glacial cirque evolution: interglacial sediment contributions in Quaternary cirque widening, Westfjords, Iceland
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Group-Robot Interaction in the Wild: An Exploratory Field Study in Semi-public Spaces
No full textHow does interaction with robots differ between spontaneously formed groups and individuals?Despite increasing robot deployment in public spaces, this question remains understudied in real-world settings. We conducted a field study deploying a service stationary robot in semi-public office spaces, tracking 221 individuals (42 alone, 179 in groups) across 95 interaction opportunities. Cookies were placed on accessible trays, creating a low-barrier functional interaction opportunity (taking a cookie) while allowing observation of spontaneous social behaviors. Groups demonstrated significantly higher engagement: functional interactions and social gestures. Within groups, leader presence amplified social engagement threefold. These findings are consistent with descriptive norm theory: group presence and leader behavior were associated with increased social engagement, though context-specific factors may moderate these effects. Results highlight the potential value of group detection for robots in multi-user environments, and demonstrate the feasibility of integrating psychological theory with automated tracking to study spontaneous human-robot encounters in the wild
Changes in phenology mediate vertebrate population responses to temperature globally
No full textInternational audiencePhenotypic responses to climate affect individual fitness, but the extent to which this translates into effects on population dynamics remains poorly understood. We assemble 213 time series on phenotypes and population sizes of wild vertebrates globally and match them with local climate data. Our meta-analysis shows that morphological traits are mostly climate insensitive. However, phenology is earlier in warmer-than-average years, which contributes positively to population growth in most species. At lower latitudes, temperature has weaker effects on phenology but stronger direct negative effects on population growth, likely because these populations are less capable of tracking climate via plasticity. Variation in the phenology-mediated effect of temperature on population growth cannot be explained by latitude, generation time, migratory mode, or diet. This suggests that simple relationships between species characteristics and population responses to warming may not occur in nature. Instead, we may need to embrace ecological complexity by considering local-scale predictors that capture intra-specific variation
Is mild intellectual disability associated with a rhythmic skills impairment? A developmental perspective
No full textInternational audienceBackgroundWhile rhythm is an essential component of human development that contributes to both cognitive abilities and interactive behaviors, to date, research on rhythmic skills in individuals with mild intellectual disability (MID) – whose intellectual and adaptive functioning is impaired – is almost non-existent. If rhythmic abilities were deficient in these individuals, they could constitute a factor limiting their social integration and autonomy in daily life, that clinicians cannot neglect in their support.AimsThe aim of our study was to better understand rhythm perception and production abilities and their development between 10 and 15 years and 16–21 years in individuals with idiopathic MID, compared to typically developing (TD) individuals.Methods and proceduresFifty-seven MID and sixty-eight TD participants matched on chronological age were tested in a rhythm discrimination task and a rhythm production task, including two spontaneous motor tempo (SMT) recording and a synchronization-continuation phase in which they had to produce rhythms that were identical, slower or faster than their own SMT, and this with three different response modalities.Outcomes and resultsParticipants with MID performed worse than TD participants on all rhythmic tasks, while exhibiting a faster and more unstable SMT.Conclusions and implicationsThese findings suggest the existence of a deficit in both rhythmic perception and production skills in individuals with MID, compared to TD individuals. Our study thus helps to demonstrate the importance of a standardized assessment of rhythmic abilities and the role of these abilities in rehabilitation protocols for patients
A nonlinear micropolar continuum model with diffusion–reaction equation for remodeling of bone with trabecular lattice microarchitecture
No full textInternational audienceWe present a nonlinear micropolar continuum model that includes a diffusion–reaction equation for the remodeling of bone with a trabecular lattice microstructure. This micropolar formulation enables the modeling of bone’s adaptive response to mechanical stimuli. The remodeling process is described as a time evolution regulated by a feedback mechanism that adjusts both the orientation of the trabecular lattice microarchitecture, thanks to the micropolar formulation, and the mechanical properties, related to key morphological features such us bone density. The junctions between trabeculae are modeled as nodal points within the micropolar framework, incorporating the following energy densities: mechanical deformation, mechano-biologic contributions, and Rayleigh-type dissipation terms that control the time evolution of remodeling. We present the weak form of the energetic formulation, which includes the diffusion–reaction equation. The cases of isotropic and orthotropic material symmetries class are deduced from the general formulation. This weak formulation is adapted to the development of a computational model based on the use of the finite element method. At the end of this paper, we discuss aspects related to validation, model complexity, and possible clinical applicability
Approximating stable translation lengths on fine curve graphs
No full text17 pages, 2 figuresWe study the stable translation length of homeomorphisms of a surface acting on the fine nonseparating curve graph and compare it to the stable translation lengths of its finite approximations - mapping classes relative to a finite invariant set - acting on the nonseparating curve graph. We prove that the stable translation length of a homeomorphism with a dense set of periodic points is the supremum of the stable translation lengths of its approximations, and that the stable translation length is preserved under cell-like extensions. We deduce that homotopically triv ial homeomorphisms of the torus have stable translation length which is the supremum of the stable translation lengths of their finite approximations. We show that the supremum is not always a maximum, by proving that the stable translation length of a mapping class acting on the nonseparating curve graph is rational
New mathematics for computer performance: array algebra and cost functions
No full textMoA (mathematics of arrays) is a theory of parallel operations on arrays that can describe all known algorithms in linear algebra, signal processing, HPC because they are based on primitive-recursion and array shapes. Mapping parallel algorithms to computer architectures remains more of an art than a science and specific mathematical techniques are needed to provide a basis for performance evaluation at a level abstract enough to constitute an experimental science.In this paper we present a methodology for implicit parallel programming with MoA expressions. Then we formalize the Moa operators in an operational semantics that relates them to the linear space of memory elements in computer architecture.Then we define a theory of execution costs that can generalize all known concepts of this kind, is based on classical operations research and is formally related to MoA-based parallel programming. It constitutes the basis for a formalized and mechanizable approach to performance prediction, portability and maximization.</div
TIGRÉ : LA GUERRE OUBLIÉE DE LA CORNE DE L'AFRIQUE: Entre centralisation autoritaire et fédéralisme ethnique, un conflit de haute intensité aux ramifications régionales (2020-2022) Entre centralisation autoritaire et fédéralisme ethnique, un conflit de haute intensité aux ramifications régionales (2020-2022)
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