HAL Université de Toulouse, et Toulouse INP
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Euclid Quick Data Release (Q1). Quenching precedes bulge formation in dense environments but follows it in the field
No full textInternational audience(Abridged) The bimodality between star-forming discs and quiescent spheroids requires the existence of two main processes: the galaxy quenching and the morphological transformation. In this paper, we aim to understand the link between these processes and their relation with the stellar mass of galaxies and their local environment. Taking advantage of the first data released by the Euclid Collaboration, covering more than 60 deg2 with space-based imaging and photometry, we analyse a mass-complete sample of nearly one million galaxies in the range 0.2510^{9.5} M_\odot$. We divide the sample into four sub-populations of galaxies, based on their star-formation activity and morphology. We then analyse the physical properties of these populations and their relative abundances in the stellar mass vs. local density plane. Together with confirming the passivity-density relation and the morphology-density relation, we find that quiescent discy galaxies are more abundant in the low-mass regime of high-density environment. At the same time, star-forming bulge-dominated galaxies are more common in field regions, preferentially at high masses. Building on these results and interpreting them through comparison with simulations, we propose a scenario where the evolution of galaxies in the field significantly differs from that in higher-density environments. The morphological transformation in the majority of field galaxies takes place before the onset of quenching and is mainly driven by secular processes taking place within the main sequence, leading to the formation of star-forming bulge-dominated galaxies as intermediate-stage galaxies. Conversely, quenching of star formation precedes morphological transformation for most galaxies in higher-density environments. This causes the formation of quiescent disc-dominated galaxies before their transition into bulge-dominated ones
Integrins on alveolar macrophages shape the fate of M. tuberculosis in the alveolar space: A proof of concept using genetically engineered mouse models.
No full textIntegrins are an important family of adhesion receptors that are widely distributed among immune cells in the lungs. There is growing evidence that integrins play a complex role in the immune system in response to infectious lung diseases. However, little is known about their contribution in TB infection, especially when the bacilli encounter macrophages in the alveolar space. Using an innovative animal approach to specifically disable integrin activation, we investigated whether alveolar macrophage integrins contribute to bacterial burden in the lungs early after infection of mice with M. tuberculosis. We then examined whether integrins are necessary for the infection of alveolar macrophages by M. tuberculosis and subsequently for the intercellular propagation of bacilli within the framework of the alveolar environment. In parallel and to better understand the contribution of integrin activity in alveolar macrophages, we used a complementary strategy based on the adoptive transfer of long-term expanded alveolar macrophages (mexAMs) from Talin1-deleted mutant mice or littermate control mice. We used mice with a conditional deletion of the Talin1 gene under the control of LysM-Cre together with ROSA-EYFP reporter alleles for tracing the cells expressing Cre. Our data indicated that disarming Talin1 in myeloid cells so that it can no longer effectively regulate integrins expressed by alveolar macrophages determine the fate of M. tuberculosis in the alveolar space. These one-shot experiments in mice support the proposition that integrins in myeloid cells contribute to the lung burden of M. tuberculosis, and that integrins are involved in the infection of alveolar macrophages in the local pulmonary environment shortly after infection. We cannot conclude that this has any effect on the spread of the bacterium to other subsets of phagocytes in the lung. Instead, we propose that the blockade of alveolar macrophage infection is compensated by neutrophil infection. Interestingly, neutrophils recruited to the lung at an early stage can harbor M. tuberculosis and are long-live enough to allow bacteria replication in vivo. This could help restore the bacterial load in the lungs at 21 dpi. Our in vitro studies also indicated that Talin1-deletion in mexAMs did not affect cell infection or bacterial growth, but although preliminary, they strongly suggest that Talin1 is required for H37Rv dissemination from mexAM to mexAM. This initial project, now successfully completed, allows us to raise further crucial questions about how and which integrins contribute at the molecular and cellular level to each of the key steps of M. tuberculosis infection with the aim of ultimately interfering with the spread of the bacillus
Prediction of the aqueous redox properties of functionalized quinones using a new QM/MM variational formulation
No full textInternational audienceWe recently proposed to couple quantum mechanics (QM) methods with molecular density functional theory (MDFT) to describe mixed quantum-classical systems [J. Chem. Phys. 161, 014113 (2024)]. This approach is particularly appropriate to account for solvent effect into QM calculations. Motivated by the growing interest in quinones as potential electrolytes for aqueous redox-flow batteries, we apply the QM/MDFT framework to compute the two-electrons redox potentials of a series of Benzoquinone/Hydroquinone couples in aqueous solution. However, since these molecules are made of several dozens of atoms, their geometries are not trivial. This motivates the development of a geometry optimization procedure within the QM/MDFT framework.To this end, we introduce a new variational formulation for the grand potential of a mixed quantum-classical system. Within the Born-Oppenheimer approximation, and neglecting electronic entropy, the quantum solute is described by a product of electronic and nuclear density matrices, both depending parametrically on coordinates of the classical solvent. It can then be shown that a functional of the total density matrix satisfies a variational principle for the grand potential. Using a mean-field approximation, we express the grand potential of the mixed quantum-classical system as a variational problem which depends only on the nuclear density matrix. The nuclei experience an external field generated by the electronic and classical one-particle densities.In practice, the computation of the grand potential is reduced to a sequence of density optimizations. First, the classical solvent density and the solute electronic density are optimized for a fixed solute nuclear geometry, using the previously reported mixed quantum mechanics/classical procedure. Subsequently, the solute geometry is optimized for a fixed solvent configuration. Finally, the redox potentials of a selection of Benzoquinone/Hydroquinone couples are computed after geometry optimizations. The predictions are in good agreement with QM calculation using a continuum solvent model and with experimental data</p
Sensory room: Naturalistic assessment of auditory and visual perception in developing children
No full textInternational audienceIntroduction: Hearing is essential for language acquisition and understanding the environment. Under-standing how children react to auditory and visual information is essential for appropriate management in case of hearing loss. Objective and subjective assessments can diagnose hearing loss, but do not mea-sure natural perception in children. We developed a "sensory room" for complementary assessment of children's perceptions so as to assess behavioral responses to meaningful natural sounds and visual stimuli in an ecologic environment suited to children.Material and methods: Sixteen normal-hearing children and 10 with congenital hearing loss before cochlear implantation, aged 13 to 32 months, were included in this feasibility study. They perceived 18 environmental sounds and 9 visual stimuli, and their behavioral responses were coded accordingly as: stopping, looking, moving, pointing, language or emotional reactions.Result: All children completed the task, demonstrating its feasibility in children. Percentage responses to auditory versus visual stimuli did not differ in normal-hearing children; those with congenital hearing loss responded like normal-hearing children to visual stimuli, but did not react to auditory stimuli. Progression in normal-hearing children's behavioral responses corresponded to cognitive and linguistic development according to age.Conclusion: The "sensory room" quantified children's responses to various auditory and visual stimuli, providing clinicians with measurable insight into the children's sensory perception and processin
Improvement and suitability of analytical method for the detection of tire and road wear particles markers in low-concentration sediment and soil matrices
No full textInternational audienceTire and road wear particles (TRWP) are formed by the friction between the tire and road. Despite being a massive, global and emerging pollution, their quantification and tracing are currently uncertain in environments far from roads due to a lack of optimized approaches. Pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC-MS) is a central technique in environmental research devoted to the TRWP topic. Herein, we present a more sensitive and selective approach based on the Py-GC-MS technique for detecting and quantifying TRWP in matrices far from emission sources. This approach involves sample purification and analytical optimization steps focused on: i) preliminarily removing interfering organic compounds from samples, ii) choosing the most selective markers to improve peak resolution in chromatograms and iii) improving the recovery rates (up to 100–108 %) for selected elastomers (SBR and NR). The markers that are identified for reliably quantifying elastomers in low-concentration matrices far from sources are 4-phenylcyclohexene for styrene butadiene rubber and dimethylvinylcyclohexene for natural rubber. Using internal standards for calibration and acquiring data in single ion monitoring mode allowed us to achieve limits of detection as low as 7.7 µg/g for SBR and 3.8 µg/g for NR. Finally, we evaluated the performance obtained by comparing the SBR and NR contents of low-concentration soils and sediments using our optimized Py-GC-MS technique and the Py-GC tandem mass spectrometry (Py-GC-MS/MS)
Acceptability and implementation potential of colorectal cancer screening and health literacy training: A qualitative study among general practitioners in deprived areas
No full textInternational audienceBackgroundColorectal cancer (CRC) is a significant contributor to cancer-related burden, ranking second in cancer mortality in France. Despite the proven survival benefits of systematic CRC screening, uptake remains suboptimal, particularly among people with limited health literacy (HL) and lower socioeconomic position. This study aimed to assess the acceptability of an e-learning training programme on HL and CRC screening among general practitioners (GPs) in deprived areas while also exploring strategies for its promotion and scale-up.MethodsA qualitative study nested within the DECODE cluster-randomised controlled trial (NCT04631692) across four French regions was conducted. Semi-structured interviews (phone or online) were carried out to capture opinions, experiences, and recommendations of GPs in the intervention arm. Thematic analysis, employing manual and NVivo coding, was performed.ResultsThe majority of 22 GPs (16/22) found the training acceptable, informative, tailored to their knowledge needs and offering great flexibility of use. The module on HL garnered more interest than the one on CRC screening, as it addressed a relatively new area for many GPs. It facilitated reflection on patient communication techniques and identified areas for improvement in physician-patient interaction. A perceived gap in the training was the insufficient interactivity in both didactic and virtual group sessions.ConclusionThe findings of this study show high acceptability of the e-learning training by participants, indicating a potential for implementation, if kept concise, self-paced, asynchronous, and with a stronger focus on HL. The training helped GPs reflect on their practices, enhance HL knowledge, and improve patient communication strategies, leading some to adopt new techniques in daily interactions with low HL patients, beyond just screening
Polyconvex double well functions
No full textThis version fixes a flaw in the main theorem of the previous version.We investigate polyconvexity of the double well function for given matrices . Such functions are fundamental in the modeling of phase transitions in materials, but their non-convex nature presents challenges for the analysis of variational problems. Polyconvexity of is related to the singular values of the matrix difference . We prove that is polyconvex if and only if the square of the largest singular value does not exceed the sum of the squares of the other singular values. This condition allows the function to be decomposed into the sum of a strictly convex part and a null Lagrangean. As a direct application of this result, we prove an existence and uniqueness theorem for the corresponding Dirichlet minimization problem of the integral functional
Identifying indicators of consciousness in AI systems
No full textInternational audienceRapid progress in artificial intelligence (AI) capabilities has drawn fresh attention to the prospect of consciousness in AI. There is an urgent need for rigorous methods to assess AI systems for consciousness, but significant uncertainty about relevant issues in consciousness science. We present a method for assessing AI systems for consciousness that involves exploring what follows from existing or future neuroscientific theories of consciousness. Indicators derived from such theories can be used to inform credences about whether particular AI systems are conscious. This method allows us to make meaningful progress because some influential theories of consciousness, notably including computational functionalist theories, have implications for AI that can be investigated empirically
Practices, Perspectives and Perceived Difficulties in Early Detection of Autism among Early Childcare and Education Providers in France
No full textInternational audienc
Nonlinear modeling of AlN/GaN HEMT accounting for self-biasing effect during RF step stress: analysis and hard-SOA
No full textplateforme PROOF LAASInternational audienceIn this study, we investigate the non-linear (NL) behavior of AlN/GaN HEMT technologies under gain compression when submitted to 10 GHz single-tone RF-step stress, which is crucial for millimetre-wave power application robustness. We evaluate AlN/GaN transistors, targeting high-power amplifiers with operating frequency above 30 GHz. We present here an original method that includes, in a unique NL expression, the varying self-biasing effect caused by RF step-stress sequences. This methodology can be used as a tool for comparative analysis of technological variants and various transistor geometries post RF stress. The step-stresses are conducted on HEMT in saturated mode and in diode operation alone, to assess the electrical origins of defects and the critical Safe Operating Area (SOA) of these devices. We identify the mechanism of failure as stemming from the degradation of the Schottky gate when subjected to critical RF power levels, due to its constrained capacity to handle power signals exceeding 18 dBm. Furthermore, we highlight the remarkable RF robustness of this technology, achieving gain compression of around 10 dB without degradation