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Thermodynamically consistent phase field modeling of ice crystallization in H 2 O − N a C l solutions: Mechanisms of solute inclusion and interface dynamics
No full textInternational audienc
Thermochemical and catalytic degradation of axlebox grease: Experimental data and kinetic model
No full textInternational audienc
Shifting Drivers of Holocene Fire Regimes in Uzbekistan: From Natural Factors to Anthropogenic Impact
No full textInternational audienceIn the context of the current fire intensification associated to climate aridification, this study explores Holocene fire regimes in the foothills of the Pamir-Alai Range (Uzbekistan) through macro-charcoal analysis of sediment cores from Lake Fazilman and the Ogshagil wetland, spanning the past 11000 years. In addition to their novelty, the results reveal distinct fire phases driven by both climatic fluctuations and human activities. During the early Holocene (12000–5000 cal. yr BP), fire activity was primarily climate-driven, with higher frequencies during arid phases. A significant shift occurred around 4000 – 3000 cal. yr BP, with synchronous fire trends at both sites suggesting increased anthropogenic influence linked to agro-pastoral practices of the Oxus Civilization, the Andronovo Cultures and the Handmade Painted Ware Cultures. Fire frequency declined during periods of intensified agricultural practices but increased again in later centuries, likely influenced by shifts in land use and socio-economic dynamics. Over the past 500 years, a rise in fire activity and woody plant combustion, likely influenced by post-medieval pastoral land use and firewood transportation, suggests intensified human impact. This study provides new insights into the interplay between climate, vegetation, human activity and fire in shaping Central Asia's steppe landscapes
Gli startupper francesi se ne fregano: un’analisi multimodale della locuzione «on s’en fout»
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The Impact of Mental Images on Reasoning: A Study on Aphantasia
No full textInternational audienceThere is a long-standing debate about the role of visual mental images in reasoning. Knauff and Johnson-Laird's (2002) Visual Imagery Impedance Hypothesis (VIIH) suggests visual imagery can hinder abstract reasoning, as evidenced by slower responses to visual compared to spatial and control problems. Aphantasia -reduced or absent visual imagery-offers a unique opportunity to test this hypothesis. In an online version of the reasoning paradigm used in VIIH studies, aphantasic and control participants completed three problem types (visual, spatial, control), while reaction time and accuracy scores were measured. In addition, a second classification, based on the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ), was employed to differentiate participants according to their cognitive style and explore possible performance differences between the visualiser, spatialiser and verbaliser clusters. Our study replicated the findings of Knauff and Johnson-Laird (2002), as a slowdown for visual problems in comparison to spatial and control ones was demonstrated in typical imagers. In aphantasics, this effect was less marked, but the difference between the groups is not substantial enough to be conclusively established. More in-depth analyses distinguishing "complete aphantasia" and hy-pophantasia revealed a more significant slowdown within the latter group, suggesting that visual imagery, even in its weakest form, influences performance on such tasks. Finally, our OSIVQ classificationbased analyses showed that participants in the visualiser cluster are the most impaired in this task. Overall, our results demonstrated the importance of considering the influence of mental images and cognitive styles in theories of reasoning
Target controllability for a minimum time problem in a trait-structured chemostat model
No full textIn this paper, we consider a minimum time control problem governed by a trait-structured chemostat model including mutation and one limiting substrate. Our first main result proves the well-posedness of the control-to-state mapping. We subsequently analyze the class of {\it{auxostat-type controls}}, feedback laws designed to regulate substrate concentration, and prove that the corresponding solutions converge to a stationary state of the system. These convergence results are used to show the reachability of a target set corresponding to the selection of a population with a low weighted averaged half-saturation constant. Finally, we show the existence of an optimal control for the minimum time problem associated with reaching the target set. These theoretical findings are completed by numerical simulations
Two-stage fast pyrolysis and catalytic steam reforming of corn waste bio-oil for hydrogen production: Screening and optimization of Ni-Fe catalysts supported on porous clay heterostructures
No full textfffInternational audienceliste mot clef
Measurement report: Emission factors and organic aerosol source apportionment of shipping emissions in the coastal city of Toulon, France
No full textInternational audienceAbstract. Maritime transport exerts a substantial influence on local air quality, particularly in port cities. Ship emissions are recognized as major contributors to air pollution, with comparable magnitude to those of road transport. This study, conducted in 2021 in Toulon, a port city on the French Mediterranean coast, assessed ship emissions one year after the implementation of IMO2020 sulfur regulations. Emission factors (EFs) were determined for key pollutants such as SO2, NOx, CO, NO, CH4 and particulate matter (PM), including black carbon (BC), organics (Org), sulfate (SO42-), nitrate (NO3-), ammonium (NH4+), and polycyclic aromatic hydrocarbons (PAHs), as well as the particle number concentration (PN). The IMO2020 regulation led to a marked reduction in sulfur-related emissions, whereas pollutants such as BC, Org, and PAHs remained at pre-regulation levels. Positive Matrix Factorization (PMF) analysis of PM1 organic aerosol (OA) measured by a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was used to investigate shipping contribution to local air quality. PMF successfully distinguished between road and marine transport emissions, revealing a shipping contribution to the total OA of 11.2 %. Eight factors were resolved: three shipping-related OA, a Hydrocarbon-like OA (HOA), a Cooking-like OA (COA), an Oxidized Hydrocarbon-like OA (OxHOA), a Less Oxidized OA (LOOA), and a More Oxidized OA (MOOA). Shipping and HOA factors were the dominant contributors to ultrafine particles, accounting together for 51.9 % of the alkylated PAHs (APAHs). These findings highlight the persistent influence of shipping emissions in port areas and demonstrate the effectiveness of advanced source apportionment methods to improve emission monitoring strategies, particularly as the Mediterranean region prepares for the implementation of Emission Control Area (ECA) regulations in 2025
Détection de sites archéologiques par réseaux de neurones : état d'avancement du projet Archéolog'IA
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Streptococcus pneumoniae S protein activates PBP1a to regulate peptidoglycan remodelling and cell division.
No full textInternational audienceClass A penicillin-binding proteins (aPBPs) are involved in the biosynthesis and remodelling of peptidoglycan (PG). The human bacterial pathogen Streptococcus pneumoniae produces three aPBPs, which are regulated to maintain the bacterium's ovoid shape. Evidence suggests that PBP1a and PBP2a activities are closely coordinated; however, their precise functions remain unclear. Here we characterized the pneumococcal S protein, which contains a LysM-PG-binding domain and a GpsB-interacting domain. Using S protein fusion constructs or mutant bacterial strains, we show that S protein localizes to the division ring and is required to prevent premature cell lysis and minicell formation due to aberrant division site placement. S protein interacts with PBP1a and activates its PG synthesis activity. Co-immunoprecipitation experiments combined with biochemical, genetic, structural prediction and microscopy analyses suggest that S protein is part of a larger multiprotein complex containing aPBPs and PG-modifying enzymes, and coordinated by the scaffolding protein GpsB. Together, these findings suggest that a GpsB-associated complex orchestrates PG biosynthesis and remodelling in S. pneumoniae