HAL-INSU
Not a member yet
203706 research outputs found
Sort by
Post-traumatic stress disorder in adult population of La Palma (Spain) after the 2021 Tajogaite eruption : Environmental and sociodemographic predictors
No full textco auteur étrangerInternational audienceThe adverse mental health effects of exposure to disasters have long been recognized.Concerning PTSD and volcanic eruptions specifically, most studies have highlighted risk factors related to demographic and social factors (e.g., gender, age, and education), mental health, and those associated with the experience of the volcanic eruption (e.g., having evacuated). Establishing the demographic scope of those more likely to suffer PTSD following volcanic eruptions, as well as understanding the aggravating factors, is key to optimizing precautionary measurements and psychological interventions. In this study, we complement these analyses by exploring the role of environmental contaminants (specifically, exposure to tephra falls and exposure to SO₂ ) together with demographic, health, and hazard experiences in contributing to PTSD. We focus on data collected after the 2021 eruption of the Tajogaite volcano (La Palma, Spain). Our results show that in addition to sex, education, distance from the volcano, evacuation status, health issues related to the eruption, mental health antecedents, and exposure to poor air quality (i.e., SO₂ concentrations) are associated with higher scores of reported symptoms associated with PTSD. Our findings establish a picture of the prevalence of reported PTSD symptoms in various demographics groups and aggravating factors following the 2021 eruption of the Tajogaite volcano. Next steps could include an extended investigation of the role of air quality (as a potential synergic hazard) in shaping mental health following exposure to a primary hazard, such as a volcanic eruption.</p
Machine learning spectral clustering techniques: Application to Jovian clouds from Juno/JIRAM and JWST/NIRSpec
No full textInternational audienceWe present a new method, based on a joint application of a principal component analysis (PCA) and Gaussian mixture models (GMM), to automatically find similar groups of spectra in a collection. We applied the method (condensed in the public code chopper.py ) to archival Jupiter spectral data in the 2–5 µm range collected by NASA Juno/JIRAM in its first perijove passage (August 2016) and to mosaics of the great red spot (GRS) acquired by JWST/NIRSpec (July 2022). Using JIRAM data analyzed in previous work, we show that using a PCA+GMM clustering can increase the efficiency of the retrieval stage without any loss of accuracy in terms of the retrieved parameters. We show that a PCA+GMM approach is able to automatically identify spectra of known regions of interest (e.g., belts, zones, GRS) belonging to different clusters. The application of the method to the NIRSpec data leads to detection of substructures inside the GRS, which appears to be composed of an outer halo characterized by low reflectivity and an inner brighter main oval. By applying these techniques to JIRAM data, we were able to identify the same substructure. We remark that these new structures have not been seen before at visible wavelengths. In both cases, the spectra belonging to the inner oval have solar and thermal signals comparable to those belonging to the halo, but they present broadened 2.73 µm solar-reflected peaks. Performing forward simulations with the NEMESIS radiative transfer suite, we propose that the broadening may be caused by differences in the vertical extension of the main cloud layer. This finding is consistent with recent 3D fluid dynamics simulations
Emplacement and tectono-magmatic fabric development in the Upper Triassic-Lower Jurassic Curaco Batholith (northern Patagonia, Argentina) during progressive deformation: an integrated remote sensing, field, microstructural, and CPO study
No full textInternational audienceThis study integrates new field geological-structural mapping, microstructural analysis, and quartz-feldspar crystallographic preferred orientation data obtained through electron backscatter diffraction (CPO-EBSD) of the Upper Triassic-Lower Jurassic Curaco Batholith (39 • 43′S-67 • 40′W) in northern extra-Andean Patagonia, Argentina. Field relationships, geometric-kinematic, and dynamic structural analysis indicate that the batholith's emplacement coincided with movements along an approximately E-W-trending dextral strike-slip brittle-ductile shear zone, influenced by regional NE-SW oblique extension and pre-existing NW-SE-trending Paleozoic basement fabric. The alternation of igneous intrusions and deformation structures is consistent with its syntectonic emplacement by incremental growth of a pluton-dike system, fed by multiple small injections during a singlephase progressive transtensional event. The internal structural fabric gradually transitions from magmatic to sub-magmatic flows and from high-to low-temperature solid-state ductile-brittle deformation at all scales, indicating melt-present deformation and progressive fabric development under changing deformation conditions. As the batholith cools and crystallizes, the preferred shape orientations of minerals in the fabrics change, successively controlled by magmatic and tectonic processes. Combining published and new zircon U-Pb dates of 224-183 Ma provides constraints on the timescale of these tectono-magmatic processes, which are spatially and temporally related to regional intracontinental deformation in northern Patagonia during the early stages of the breakup of western Gondwana
Ageing of organic materials at the surface of Mars: A Raman study aboard Perseverance
No full textInternational audienceThe Perseverance rover is exploring Jezero crater on Mars, one of its goals being to collect samples to be returned to Earth to search for organic remains of ancient Martian life. However, the organic content of these rocks has likely suffered from the radiation environment on the surface of Mars to an extent yet to be quantified. For the first time, a 1000 sols long ageing experiment was conducted at the surface of Mars, i.e. under actual Martian conditions, relying on the 100 % organic Ertalyte target carried by Perseverance. White at landing, the Ertalyte target has turned brown with time, while its Raman signal changed, with a modification of the background (its maximum has shifted from 1500 to 2000 cm -1 ) and a reduction of the contribution of the Raman signal of Ertalyte (by a factor of 5 over the first 500 sols). Given the intrinsic resistance of the Ertalyte to UV exposure, which is not anticipated for most Martian organic materials, these results suggest that exposure at the surface of Mars will make the detection of Martian organic molecules challenging
Dossier de candidature à l'inscription sur la Liste du patrimoine mondial du pic du Midi et son observatoire.
No full textBrief communication: Sensitivity of Antarctic ice shelf melting to ocean warming across basal melt models
No full textInternational audienceThe uncertain sensitivity of Antarctic ice shelf basal melt to ocean warming strongly contributes to uncertainties in sea level projections. Here, we explore the response of five basal melt models to an idealised subthermocline warming. Total melt increases by 67 %-240 % ( + 1 °C) or by 141 %-680 % (+2 °C), showing a large intermodel spread. For deep regions of presently fast-melting ice shelves, this spread can reach 2 orders of magnitude. Therefore, a consistent calibration to present-day conditions does not guarantee consistent melt sensitivities, and several basal melt forcings should be applied to prevent underestimating uncertainties in sea level projections
Influence of secondary ice production on cloud and rain properties: analysis of the HYMEX IOP7a heavy-precipitation event
No full textInternational audienceA significant part of precipitation originates from ice crystals; however, the representation of mixed-phase clouds by atmospheric models remains a challenging task. One well-known problem is the discrepancy between the concentration of ice-nucleating particles (INPs) and the ice crystal number concentration. This study explores the effect of secondary ice production (SIP) on the properties of the Intensive Observation Period 7a (IOP7a), an intense-precipitation event observed during the HYdrological Cycle in the Mediterranean EXperiment (HYMEX) campaign. The effect of SIP on cloud and rain properties is assessed by turning SIP mechanisms in the DEtailed SCAvenging and Microphysics (DESCAM) 3D bin microphysics scheme on or off. Our results indicate that including SIP gives better agreement with in situ aircraft observations in terms of ice crystal number concentration and supercooled drop number fraction. During the mature cloud stage and for temperatures warmer than −30 °C, 59 % of ice crystals are produced by fragmentation due to ice–ice collisions, 38 % by the Hallett–Mossop process, 2 % by fragmentation of freezing drops, and only 1 % by heterogeneous ice nucleation. Furthermore, our results show that the production of small ice crystals by SIP induces a redistribution of the condensed water mass toward particles smaller than 3 mm rather than toward larger ones. As ice crystals melt, this effect is also visible in the precipitating liquid phase. The shift toward smaller particles results in a reduced precipitation flux of both ice crystals and drops. Consequently, SIP induces a decrease in accumulated precipitation at the surface by 8 % and reduces heavy rainfall exceeding 40 mm by 20 %
Deep Physico-Chemical Profiling in a Flooded Mine Shaft: Understanding Water Dynamics in Gardanne Lignite Mine (France)
No full textInternational audienceNeutral Mine Drainage (NMD) in the flooded Gardanne lignite mine (Southern France) remains poorly understood, with persistently high Fe (30 mg/L) and SO₄ (2000 mg/L) concentrations. In 2024, a field campaign conducted in the Gérard shaft, using in-situ profiling and water sampling, reveals a deep tratification. Comparisons with 2011 data indicate a shift from a predominantly static regime with diffusive processes in the deeper part to a more dynamic system, characterized by convective loops and forced convection driven by pumping. Persistent inflows seem to influence the water column structure, shaping its stratification and internal dynamics
Environmentally relevant concentrations of microplastics and phenanthrene show limited effects on the behaviour and physiology of green crab lineages
No full textInternational audienc
Analysis of mode I fracture propagation in wood using high-resolution full-field measurements and imaging
No full textExperimental characterization of wood fracture properties raises a number of challenges: crack tip location or the application of equivalent linear elastic fracture mechanics theory to a heterogeneous and anisotropic material. This article presents the application of the Localized Spectrum Analysis, a full-field measurement method, to obtain high-resolution strain maps for the analysis of three mode I crack propagation tests on TDCB silver fir wood specimens. The strain maps presented enabled us to identify annual rings through stiffness variations, to observe internal cracks through abnormal compression zones, and to determine the material's resistance-curves, therefore its critical energy release rate. This work opens up interesting prospects for the use of new measurement methods in the characterization of wood fracture properties