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Characteristics and outcomes of ICU patients with sepsis transmitted by cats and dogs: the PETSEPSIS multicentre retrospective observational cohort study
No full textInternational audienceBackgroundMillions of households have cats or dogs as pets, and infections due to bites or scratches are increasing, with the most common pathogens being Pasteurella spp., Bartonella spp., Capnocytophaga spp, and Francisella tularensis. The objective of this study was to describe patients admitted to the intensive care unit (ICU) for infection transmitted by cats or dogs, as well as their outcomes.MethodsThe retrospective multicentre observational cohort study PETSEPSIS included consecutive adults admitted to 46 ICUs in France between 2009 and 2019 for sepsis due to cat or dog bites and/or caused by any of the four above-listed bacteria. We described their features and outcomes and performed univariate and multivariate analyses to identify factors associated with death.ResultsWe included 174 patients with a median age of 64 [50–74] years; 58.1% were male. The median SAPS II score was 42 [28–58]. Mechanical ventilation was required in 51.2% of patients, for a median duration of 7 [4–13] days. Vasopressor support was used in 53.5%, renal replacement therapy in 19%, and limb amputation in 3.6% of the patients. The median ICU length of stay was 7 [4–16] days. Hospital mortality was 24.1%. The clinical presentation and severity of sepsis were similar across bacteria, although patients with Pasteurella spp. were older and had more comorbidities. Contact with cats were more often reported for Pasteurella spp. and Bartonella spp. infections and contact with dogs for Capnocytophaga spp. infections. Risk factors for hospital mortality present on ICU admission were older age, smoking, preexisting liver disease, high serum creatinine, and anaemia. Neither the type of micro-organism nor the initial antimicrobial treatment was associated with mortality.ConclusionsThis large multicentre study shows that infections transmitted by cats and dogs are infrequent reasons for ICU admission but are associated with substantial morbidity and mortality. Mortality was associated with older age and comorbidities but not with the type of microorganism or initial antibiotic treatment
Implementation of an intermediate-complexity snow-physics scheme (ISBA-Explicit Snow) into a sea ice model (SI 3 ): 1D thermodynamic coupling and validation
No full textInternational audienceSnow plays a crucial role in the formation and sustainability of sea ice. Due to its thermal properties, snow acts as an insulating layer, shielding the ice from the air above. This insulation reduces the heat transfer between the sea ice and the atmosphere. Due to its reflective properties, the snow cover also strongly contributes to albedo over ice-covered regions, which gives it a significant role in the Earth's climate system. Current state-of-art climate models use overly simple representations of the snow cover overlaying the sea ice. The snow cover is often represented with a one-layer scheme, assuming a constant density, no wet or dry metamorphism, or that no liquid water is stored in the snow. Here we implemented an intermediate-complexity snow-physics scheme (ISBA-Explicit Snow) into a sea ice model (SI3), which serves as the sea ice component for upcoming versions of the CNRM-CM climate model. This is, to our knowledge, the first time that a snow model with such a level of complexity has been incorporated into a sea ice model designed for global to regional applications. We validated our model by comparing 1D simulations with data from the Surface Heat Budget of the Arctic Ocean (SHEBA) but also simulations from another advanced snow-on-sea ice model (SnowModel-LG), as well as simulations with the previous SI3 snow scheme. Our model simulates realistic snow thicknesses, densities, and temperatures, aligning well with SHEBA observations and SnowModel-LG outputs, while capturing their temporal variability. We show that the thickness, density, and thermal conductivity of the snowpack are significantly affected by the choices made in parameterization for calculating snowfall density and wind-induced snow compaction and by the choice of the atmospheric forcing. Unlike the previous SI3 snow scheme that assumed constant density and thermal conductivity, our model realistically simulates the evolution of these properties, resulting in more accurate temperatures at the snow–ice interface. Ultimately, our study shows that modeling the temporal changes in the density and thermal conductivity of the snow layers leads to more realistic upper sea ice temperatures and therefore to a more accurate representation of heat transfer between the underlying sea ice and the atmosphere
Intensity and dynamics of extreme cold spells of the 21st century in France from CMIP6 data
No full textInternational audienceAbstract. Cold extremes significantly impact society, causing excess mortality, strain on healthcare systems, and increased demand on the energy system. With global warming, these extremes are expected to decrease, as observed in various indicators. This study simulates extreme cold spells of 15 d using a stochastic weather generator (SWG) based on circulation analogues and importance sampling, adapted for CMIP6 data. Our results show that the most extreme cold spells decrease in intensity with global warming, making 20th-century-like events (e.g., 1985 in France) nearly impossible by the end of the 21st century. However, some events of similar intensity may still occur in the near future. Such events are associated with patterns of atmospheric dynamics that convey cold air from high latitudes into Europe. Those atmospheric circulation patterns show a consistent high-pressure system over Iceland and a strong low-pressure system over southwestern Europe in ERA5 and CMIP6 models. We show that nudging the SWG towards this type of pattern triggers extreme cold spells, even in a warmer world. We also show that most CMIP6 models accurately represent this atmospheric pattern. This study highlights the importance of understanding cold spell dynamics and the relevance of rare events algorithms and large ensemble models to simulate low-probability, high-impact events, offering insights into the future evolution of cold extremes
Investigating aerosols as a way to reconcile K2-18 b JWST MIRI and NIRISS/NIRSpec observations
No full textInternational audienceRecent JWST observations of the temperate sub-Neptune K2-18 b with NIRISS SOSS/NIRSpec G395H and MIRI LRS have yielded apparently inconsistent results: the MIRI spectra exhibit spectral features nearly twice as large as those seen at shorter wavelengths, challenging the high-metallicity, CH4-rich nonequilibrium model that fits the NIRISS/NIRSpec data. We performed a suite of atmospheric retrievals on both datasets, including free-chemistry, nonequilibrium, and aerosol models, using laboratory-derived complex refractive indices for a variety of photochemical haze analogs. Free retrievals systematically output lower metallicities than inferred by self-consistent chemical disequilibrium models, and the inclusion of absorbing aerosols, especially CH4-dominated, nitrogen-poor tholins, can further reduce the inferred metallicity by over an order of magnitude. These hazes reproduce the observed NIRISS slope through scattering and match MIRI features via C–H bending absorption near 7 μm, while yielding particle properties consistent with photochemical production in H2-rich atmospheres. Although their inclusion improves the joint fit and reduces tension between datasets, it also significantly lowers the retrieved CH4 abundance, highlighting degeneracies between metallicity, composition, and aerosol properties. Our results underscore the importance of aerosol absorption in interpreting temperate sub-Neptune spectra and motivate future JWST observations and laboratory work to break these degeneracies
Rhumatismes inflammatoires chroniques et comorbidités : analyse des cohortes en population générale Gazel et Constances
No full textRheumatic inflammatory diseases (RID) are characterized by persistent articular and systemic inflammation, leading to musculoskeletal system impairment as well as a possible increased risk of cardiovascular diseases (CVD), which may be directly driven by systemic inflammation. The main objective of this work was to evaluate the association between RID and the occurrence of CVD compared to the general population, and also to determine which factors may be involved in this risk. The first part of this work assessed the association between rheumatoid arthritis (RA) related autoimmunity in the Gazel cohort, since this autoimmunity may be present several years before the clinical onset of the disease. Secondly, literature was systematically reviewed to assess the longitudinal evolution of the CVD risk among the most prevalent RID, over the last decades. A meta-analysis was specifically performed to evaluate the evolution of the risk of CVD in spondyloarthritis (SpA) and psoriatic arthritis (PsA), which was less studied in the literature. A third analysis was conducted in the population-based French cohort Constances, in order to evaluate the prevalence of RID in this cohort, and to assess its association with the occurrence of CVD, taking into account other confounding factors such as standard CV risk factors and comorbidities, which are potentially associated to RID. These studies have shown an increased risk of CVD occurrence in RID subjects compared to control population, which seemed to be related to the RID themselves, mediated by the chronic inflammation. Even if this risk seemed to have decreased over the last decades for RA and PsA, we still found a significant increase of CVD occurrence in RID patients. Biological therapies, introduced into routine clinical practice between 2000 and 2010, together with tight‐control management strategies, may explain the observed decline. However, further studies that specifically evaluate the impact of these treatments are required. We will address this remaining question in an additional study combining the data of the Constances cohort matched to those of the medico-administrative French database (SNDS data).Les rhumatismes inflammatoires chroniques (RIC) sont caractérisés par une inflammation persistante, à la fois articulaire et systémique, pouvant entrainer une altération du système musculosquelettique, ainsi qu’une augmentation potentielle du risque de maladies cardiovasculaires (MCV), qui pourrait être liée à l’état inflammatoire systémique. L’objectif principal de ce travail était d’étudier l’association entre les RIC et la survenue de MCV en comparaison à la population générale, et d’identifier les facteurs susceptibles de contribuer à ce risque. Un premier travail a été d’évaluer si l’auto-immunité liée à la polyarthrite rhumatoïde (PR) était associée à la survenue de MCV, par l’étude dans la cohorte Gazel de sujets présentant des auto-anticorps mais exempts de PR, en comparaison à des sujets sains sans auto-anticorps. Le deuxième travail a consisté en une revue systématique de la littérature sur l’évaluation, au cours de ces dernières décennies, de l’évolution du risque de survenue de MCV chez les principaux RIC. Une méta-analyse a été réalisée spécifiquement pour la spondylarthrite (SpA) et le rhumatisme psoriasique (RPso), pathologies pour lesquelles le risque de MCV a été moins étudié. Un troisième travail a porté sur l’analyse de la cohorte en population générale Constances, afin d’étudier les RIC dans cette cohorte récente et d’évaluer leur association avec la survenue de MCV, en prenant en compte comme facteurs de confusion les facteurs connus de risque CV et les comorbidités possiblement associées aux RIC. Ces travaux ont mis en évidence une majoration du risque de survenue de MCV chez les RIC en comparaison à la population générale, indépendamment des causes connues, et suggèrent que ce sur-risque est lié aux RIC en eux-mêmes, par l’inflammation chronique qu’ils engendrent. Bien que ce sur-risque semble avoir diminué pour la PR et le RPso ces dernières décennies, il persiste une majoration significative du risque pour l’ensemble des trois RIC étudiés. Les traitements de fond comme les biothérapies, utilisés en pratique courante depuis les années 2000-2010, ainsi que la prise en charge médicale récente avec des objectifs stricts de contrôle de l’inflammation, pourraient avoir contribué à la réduction de ce risque. Aussi, l’étude complémentaire de l’effet de ces traitements parait nécessaire à l’avenir afin de déterminer leur rôle propre. Ce point sera abordé en poursuivant le troisième travail après l’autorisation d’accès aux données de la cohorte Constances appariées au Système National des Données de Santé (SNDS)
Three-dimensional Reconstruction and Propagation of an Asymmetric Flux-rope Coronal Mass Ejection
No full textInternational audienceWe report on the characterization of a coronal mass ejection (CME) observed on 22 October 2003 by the LASCO-C2 and C3 coronagraphs over a time interval of 6 hours. This CME clearly appears as an asymmetric flux-rope in self-similar expansion and in spite of having a single vantage point, this relatively simple morphology and the geometry of the observations allow us to reconstruct its shape and its trajectory. The images are first processed in order to remove most of the background or foreground coronal structures (essentially streamers) which are superimposed on the CME. The analysis is based on forward modeling of an asymmetric structure where the plasma is homogeneously distributed in a thin shell and synthetic images are calculated from Thomson scattering by the electrons. They are best fitted to the images to determine the exact shape of the flux rope, and to track its evolution characterized by a radial propagation in self-similar expansion. The analysis supports the forward propagation (over the backward one) characterized by constant accelerations of 76 and 46 m/sec^2 for the front and rear parts of the CME, respectively. The respective velocities at 20 Rsun reach 2000 and 1100 km/s, and its mass unbiased by projection effects is estimated at 1.7x10^16 g. Altogether, these are quite exceptionally large values among CMEs and imply a very energetic event. No erupting event could be identified at or near the calculated initial location of the CME. It lies 25° west of the active region NOAA 10484, the site of contemporary, violent, and recurrent solar eruptions (the ``Halloween event'') and a putative connection would require a strong deflection over a very short path. Therefore, the origin of this CME remains unclear
Hardy, witness to his ‘time’: the city facing the Little Ice Age
No full textNational audienceAmong historians, it has been fashionable for decades to explain that the deep roots of the French Revolution lay primarily in the philosophical and political thinking of the Enlightenment. Without questioning this view, this contribution reintroduces the role of climate in the revolutionary process of 1789 by showing that the political, economic and social crisis was greatly amplified by unfavourable weather conditions, the impact of which on food supplies partly explains popular discontent
Visualizing Respiratory Syncytial Virus Replication in Live Mice
No full textInternational audienceModeling human respiratory syncytial virus (RSV) infection in vivo is an essential step in the search for novel vaccines, antiviral therapies, or preventive measures against RSV disease. The most commonly used experimental models of RSV infection are rodent models, in particular, inbred BALB/c mice and cotton rats (Bem et al., Am J Physiol Lung Cell Mol Physiol 301(2): L148–L156, 2011; Taylor, Vaccine 35(3): 469–480, 2017; Altamirano-Lagos, Front Microbiol 10: 873, 2019). However, depending on the RSV strain and viral titer, infection of mice with RSV can result in few or no symptoms, with viral load being estimated by RT-qPCR on lung tissue. By allowing the monitoring of the spread and intensity of the infection in the same animal over time, the use of recombinant RSV expressing the firefly luciferase represents a major advance in the study of RSV replication in the murine model