Search Results (44)

Lakes are threatened by contemporary climate change and human activities. Paleohydrological records provide important evidence for developing scenarios for future changes in the availability of freshwater resources. This study presents a synthesis of a sedimentological, archeological, and chronological dataset collected from Lake Annecy (eastern France) to reconstruct a lake-level record documenting the whole Holocene. This dataset shows a pronounced minimum in the lake level during the Holocene thermal maximum (HTM) (ca. 9000–7000 cal BP), preceded by a general lowering trend (early Holocene), and followed by a general rising trend (Neoglacial). On both the millennial and centennial scales, the Lake Annecy record appears to match the regional pattern of Holocene lake-level fluctuations established for West-Central Europe. In agreement with other extra-regional paleoclimatic records, it shows the dominant influence of orbital forcing. The high magnitude of the lake-level lowering (more than 5 m) during the HTM, with a 2–2.5 °C difference between the HTM and the pre-industrial mean summer temperatures, suggests possible drastic lake-level lowering phases in the near future depending on the IPCC scenarios following climate change. This would mean dramatic impacts on human activities and the preservation of exceptional archeological remains in regional lake basins. Full article

The number and diversity of groundwater bodies (GWBs) in large French administrative regions pose challenges to their monitoring and protection by regional health agencies. To overcome this obstacle, we propose, for the Auvergne-Rhône-Alpes region (about 70,000 km²), a grouping of GWBs into homogeneous groups based on the sources of variability within a large dataset of groundwater physico-chemical and bacteriological characteristics (8078 observations and 13 parameters). This grouping involved a dimensional reduction in the data hyperspace by principal component analysis (PCA) and a clustering based on the mean values of each GWB on the factorial axes. The information lost when clustering from the sample point scale to the GWB scale and then to that of the GWB group was quantified by analysis of variance and showed that grouping GWBs is accompanied by a small loss of information. A discriminant analysis confirmed the high spatial and temporal variability within the dataset, as well as the effectiveness of the proposed method for establishing homogeneous sets. Some roadmaps for more targeted monitoring of water resources were briefly proposed. Full article

COVID-19 is an emerging disease whose impact on the return to work of hospital staff is not yet known. This study was aimed at evaluating the prevalence of delayed return to work associated with medical, personal, and professional factors in hospital staff who tested positive for COVID-19 during the second epidemic wave. A descriptive, analytical observational study was conducted. The source population consisted of all staff of a French University Hospital Center who had an RT-PCR test or an antigenic test positive for SARS-CoV-2 during the period from 6 September to 30 November 2020. A delayed return to work was defined as a return to work after a period of at least 8 days of eviction, whereas before the eviction period decided by the French government was 14 days. Data collection was carried out through an anonymous online self-questionnaire. The participation rate was 43% (216 participants out of 502 eligible subjects). Moreover, 40% of the staff had a delayed return to work, and 24% of them reported a delayed return to work due to persistent asthenia. Delayed return to work was significantly associated with age, fear of returning to work, and persistent asthenia, but the number of symptoms lasting more than 7 days was the only factor that remained significantly associated after multivariate analysis. From this study, it appears that interest in identifying the number of persistent symptoms as a possible indicator of delayed work emerges. Moreover, persistent asthenia should be given special attention by practitioners to detect a possible long COVID. Full article

Thirty-one alpine species of Cortinarius (Agaricales, Cortinariaceae) were described from the alpine zone of the Alps during the second half of the XX century, by the Swiss mycologist Jules Favre, and by the French mycologists Denise Lamoure and Marcel Bon. Notoriously difficult to identify by macro- and microscopical characters, most of these species, which belong to subgen. Telamonia, have been thoroughly revised in global publications based on type sequencing. Recent surveys in the alpine areas of France (Savoie) and Italy (Lombardy), as well as the sequencing of D. Lamoure’s collections, identified three new species that are here described and illustrated: C. dryadophilus in sect. Castanei, C. infidus in sect. Verni, and C. saniosopygmaeus in sect. Saniosi. The holotypes of C. caesionigrellus Lamoure and C. paleifer var. brachyspermus Lamoure could be sequenced. A recent collection of the former is described and illustrated here for the first time, and based on available data, the latter name is recombined as Cortinarius flexipes var. brachyspermus comb. nov. Lastly, C. argenteolilacinus var. dovrensis is reported from the alpine zone for the first time and a new combination, Thaxterogaster dovrensis comb. & stat. nov. is introduced in the present work. Full article

Despite the fact that the selective pressure of antibiotics on wild birds is supposed to be very weak, they are considered potential vectors of antimicrobial resistance (AMR). Obligate scavengers such as vultures can present high proportions of resistance to extended-spectrum cephalosporins (ESC) and multi-drug-resistant (MDR) bacteria, partially due to feeding stations that are provisioned with livestock carcasses from intensive farming. Here we investigated whether griffon vultures (Gyps fulvus) from two populations located in the French Alps, which feed on livestock carcasses from extensive farms, may carry such resistant bacteria. Phenotypic and genotypic characterization showed an 11.8% proportion of ESC-resistant bacteria, including five extended-spectrum beta-lactamase (ESBL)-producing and one AmpC-producing E. coli. The five ESBL-positive E. coli were clonal and all came from the same vulture population, proving their spread between animals. The ESBL phenotype was due to a bla_CTX-M-15 gene located on the chromosome. Both ESBL- and AmpC-positive E. coli belonged to minor STs (ST212 and ST3274, respectively); interestingly, ST212 has already been identified in wild birds around the world, including vultures. These results suggest that actions are needed to mitigate the spread of MDR bacteria through wild birds, particularly in commensal species. Full article

Monitoring variations in the extent of wet snow over space and time is essential for many applications, such as hydrology, mountain ecosystems, meteorology and avalanche forecasting. The Synthetic Aperture Radar (SAR) measurements from the Sentinel-1 satellite help detect wet snow in almost all weather conditions. Most detection methods use a fixed threshold to a winter image ratio with one or two reference images (with no snow or dry snow). This study aimed to explore the potential of image segmentation methods from different families applied to Sentinel-1 SAR images to improve the detection of wet snow over the French Alps. Several segmentation methods were selected and tested on a large alpine area of 100 × 100 km². The segmentation methods were evaluated over one season using total snow masks from Sentinel-2 optical measurements and outputs from forecasters’ bulletins combining model and in-situ observations. Different metrics were used (such as snow probability, correlations, Hamming distance, and structure similarity scores). The standard scores illustrated that filtering globally improved the segmentation results. Using a probabilistic score as a function of altitude highlights the interest in some segmentation methods, and we show that these scores could be relevant to calibrate the parameters of these methods better. Full article

We perform a first evaluation of the Copernicus pan-European wet snow products in mountainous terrain in the French Alps. Mountains are very challenging due to the complexity of the terrain and the multiple interactions between soil, snow and atmosphere that can impact the snowpack state. We focused on the evaluation of the Sentinel-1 derived SAR Wet Snow (SWS) product with the use of Sentinel-2 derived Fractional Snow Cover (FSC) products for the evaluation during wet snow periods. Comparisons were also made with snowpack reanalyses from the Crocus model. We showed that melt lines computed from the SWS product at the scale of massifs show realistic variations in elevation, orientation and season supported by comparisons with some snow variables as simulated by the Crocus model. We developed a new score, which is particularly suitable for mountain products and allows a very useful comparison of satellite products of different ground resolutions. We show that for melting periods, Sentinel-1 and Sentinel-2 snow cover probability curves calculated at the scale of a mountain range are very close for altitudes below 2000 m with RMS errors lower than 0.2. We also illustrate how the generated probability curves can be used to infer highly relevant information on the extent of snow by altitude and on its melting process evolution by connecting information from Sentinel-2 and Sentinel-1 (taking into account morning and evening orbits). Full article

Understanding mass transfer associated with fluids circulation and deformation in the Alpine orogeny is often complex due to common multistage crystallization. For example, in two emblematic and historic Pb-Ag deposits of the French Alps, Macôt-la Plagne (MP) and Peisey-Nancroix (PN), a sedimentary or orogenic origin is still debated. To discriminate between the metallogenic models of the two deposits, an integrative methodology combining field, microstructural, mineralogical, thermobarometrical, and geochronological data was here applied for establishing detailed Pressure–Temperature–Time–Deformation (P-T-t-d) mineralization conditions. Both deposits are located in Permo-Triassic quartzite of the External Briançonnais domain along the Internal Briançonnais Front (Internal Western Alps). The ore mainly occurs as veins and disseminated textures containing galena, pyrite, and variable content of tetrahedrite–tennantite and chalcopyrite. Quartz porphyroclasts and sulfide microstructures indicate a dynamic recrystallization of the quartzite during the main fluid mineralization episode. Chlorites and K-white micas (phengite) chemical analysis and thermodynamic modeling from compositional maps indicate an onset of the mineralization at 280 °C, with a main precipitation stage at 315 ± 35 °C and 6.25 ± 0.75 kbar. In situ U-Pb dating on monazite, cogenetic with sulfides, gives ages around 35 Ma for both deposits. The integrative dataset converges for a cogenetic MP-PN Alpine Pb-Ag mineralization during deformation in relation to the thrusting of the “Nappe des Gypses” and the Internal Briançonnais at the metamorphic peak. Full article

The COVID-19 pandemic has exposed health and social inequities among migrant populations. Less empirical evidence exists about the impact of COVID-19 lockdown measures on migrants. This study aimed to investigate the impact of the first lockdown in France between March and May 2020 on migrants’ lives and livelihoods. We adopted a social vulnerability framework to conceptualize how the pandemic and the consequential lockdown in France contributed to a ‘compounded crisis’ for asylum seekers and undocumented migrants. This crisis encompassed health, protection, and socio-economic challenges for migrants and exposed the shortcomings of existing government policies that exclude migrants and do not address the root causes of health inequities. The study draws on in-depth qualitative interviews conducted with 75 asylum seekers and undocumented migrants during the pandemic lockdown in the French regions of Auvergne-Rhône-Alpes and Île-de-France. The findings of this paper highlight the importance of implementing a cohesive pandemic response approach that views health as a fundamental inclusive right for all human beings and all policies as health policies to promote well-being for all. Full article

In this work, we proposed a standardized approach to characterize and map wildland-anthropic interfaces (WAI) in the neighboring areas of the Italy-France Maritime cooperation area, which includes three Italian (Sardinia, Tuscany and Liguria) and two French (Corsica and Provence-Alpes-Côte d’Azur) regions and covers approximately 93,000 km² of land. For the purpose of this study, we defined WAIs as the areas in which anthropic buildings (isolated housings, industrial, commercial structures, etc.) coexist with wildland vegetation. As the first step, we extracted raw data from different geospatial files and sources to characterize, at fine-scale, both anthropic buildings and vegetation types for the whole study area. We then reclassified anthropic blocks according to structure density and percentage of area covered, and determined the main land cover types (rural, forest, non-vegetated areas, or water bodies). In addition, we identified the so-called “intense wildfire and ember exposure grids” by determining a 2 km buffer from dense and contiguous forest areas (>5 km²). We finally combined the above layers and derived the 100 m wildland-anthropic interface raster map of the study area. The final WAI map was subdivided into four main classes: (a) anthropic: medium anthropic presence and high anthropic presence; (b) wildland-anthropic (WA): WA interface and WA intermix; (c) dispersed anthropic (DA): DA in forest areas, DA in rural areas, and DA in non-vegetated areas; (d) non-anthropic: forest areas, rural areas, non-vegetated areas, and water bodies. We then characterized total area and percentage of the diverse classes of anthropic, WA, DA, and non-anthropic areas, considering the whole study area and the five regions, and highlighted spatial differences among and within classes and regions. The results of this work can be useful to inform and optimize strategies to mitigate wildfire impacts in the surroundings of anthropic areas of the Italy-France Maritime cooperation area. Full article

Disseminated ores in porous or fractured media can be polarized under the application of an external low-frequency electrical field. This polarization is characterized by a dimensionless property that is called the “chargeability”. Induced polarization is a nonintrusive geophysical sensing technique that be used in the field to image both the electrical conductivity and the chargeability of porous rocks together with a characteristic relaxation time. A petrophysical model of the induced polarization of metallic ores immersed in a porous conductive and polarizable material is reviewed, and its predictions are compared to a large dataset of experimental data. The model shows that the chargeability of the material is linearly dependent on the volume fraction of the ore and the chargeability of the background material, which can, in turn, be related to the conductivity of the pore water and the cation exchange capacity of the clay fraction. The relaxation time depends on the grain sizes of the ores and on the conductivity of the background material, which is close to the conductivity of the porous rock itself. Five applications of the induced-polarization method to ore and metallic bodies are discussed in order to show the usefulness of this technique. These applications include: (i) A sandbox experiment, in which cubes of pyrite are located in a specific area of the tank; (ii) The tomography of an iron slag at an archeological site in France; (iii) A study of partially frozen graphitic schists in the French Alps; (iv) The detection of a metallic tank through the tomography of the relaxation times; and (v) The detection and localization of a deep ore body that is associated with a tectonic fault. We also discuss the possibility of combining self-potential and induced-polarization tomography to better characterize ore bodies below the seafloor. Full article

Climate change’s impact on water availability has been widely studied, including its impact on very rare values quantified by return levels using the statistical extreme value theory. However, the application of this theory to estimate extreme low flows is barely justified due to a large temporal dependency and a physically highly bounded lower tail. One possible way of overcoming this difficulty is to simulate a very large sample of river flow time series consistent with the observations or the climate projections in order to enable empirical rare percentile estimations. In this paper, such an approach based on simulation is developed and tested for a small mountainous watershed in the French Alps. A bivariate generator of daily temperature and rainfall, developed in collaboration with Paris-Saclay University and based on hidden Markov models, is used to produce a large number of temperature and rainfall time series, further provided as input to a hydrological model to produce a similarly large sample of river flow time series. This sample is statistically analyzed in terms of low flow occurrence and intensity. This framework is adapted to the analysis of both current climate conditions and projected future climate. To study historical low flow situations, the bivariate temperature and rainfall model is fitted to the observed time series while bias-adjusted climate model outputs are used to calibrate the generator for the projections. The approach seems promising and could be further improved for use in more specific studies dedicated to the climate change impact on local low flow situations. Full article

In this multi-centric cross-sectional survey conducted in nursing homes of the French Alps, from 1 March to 31 May 2020, we analyze the relationship between the occurrence of an outbreak of COVID 19 among residents and staff members. Out of 225 eligible nursing homes, 74 (32.8%) completed the survey. Among 5891 residents, the incidence of confirmed or probable COVID-19 was 8.2% (95CI, 7.5% to 8.9%), and 22 (29.7%) facilities had an outbreak with at least 3 cases. Among the 4652 staff members, the incidence of confirmed or probable COVID-19 was 6.3% (95CI, 5.6% to 7.1%). A strong positive correlation existed between residents and staff members for both numbers of cases (r² = 0.77, p < 0.001) and the incidence (r² = 0.76, p < 0.001). In univariate analyses, cases among the staff were the only factor associated with the occurrence of an outbreak among residents (OR = 11.2 (95CI, 2.25 to 53.6)). In bivariate analysis, this relationship was not influenced by any nursing home characteristics, nor the action they implemented to mitigate the COVID-19 crisis. Staff members were, therefore, likely to be a source of contamination and spread of COVID-19 among nursing home residents during the first wave of the pandemic. Full article

Background: The nuclear or radiation disaster risk within the French Auvergne-Rhone-Alpes state is low (but not absent) due to its proximity to four Nuclear Power Generation Centers and two regional cancer control centers. This study aims to compare subjective stress ratings for emergency health care workers regarding nuclear and radiation disasters between two locations: at work versus at home. Materials and Methods: We distributed an anonymous online questionnaire via RedCap^® to all emergency health care workers who could be involved in patient care after a nuclear or radiation disaster. It comprised 18 questions divided into three parts—theoretical knowledge and practical assessment, stress assessment, and sociodemographic criteria. Results: We analyzed 107 responses. There was a significant 11-point increase in stress levels between work and home regarding nuclear or radiation disaster risks (p = 0.01). Less than 25% of emergency health care workers surveyed benefited from annual training. Conclusion: The stress levels of emergency health care workers regarding nuclear or radiation disaster were higher at work than at home and increased without annual training. It is important to increase knowledge about these protocols and to mandate yearly training for all workers potentially involved in these disasters. Full article

We aimed to report SARS-CoV-2 seroprevalence after the first wave of the pandemic among healthcare workers, and to explore factors associated with an increased infection rate. We conducted a multicentric cross-sectional survey from 27 June to 31 September 2020. For this survey, we enrolled 3454 voluntary healthcare workers across four participating hospitals, of which 83.4% were female, with a median age of 40.6 years old (31.8–50.3). We serologically screened the employees for SARS-CoV-2, estimated the prevalence of infection, and conducted binomial logistic regression with random effect on participating hospitals to investigate associations. We estimated the prevalence of SARS-CoV-2 infection at 5.0% (95 CI, 4.3%–5.8%). We found the lowest prevalence in health professional management support (4.3%) staff. Infections were more frequent in young professionals below 30 years old (aOR = 1.59, (95 CI, 1.06–2.37)), including paramedical students and residents (aOR = 3.38, (95 CI, 1.62–7.05)). In this group, SARS-CoV-2 prevalence was up 16.9%. The location of work and patient-facing role were not associated with increased infections. Employees reporting contacts with COVID-19 patients without adequate protective equipment had a higher rate of infection (aOR = 1.66, (95 CI, 1.12–2.44)). Aerosol-generating tasks were associated with a ~1.7-fold rate of infection, regardless of the uptake of FFP2. Those exposed to clusters of infected colleagues (aOR = 1.77, (95 CI, 1.24–2.53)) or intra-familial COVID-19 relatives (aOR = 2.09, (95 CI, 1.15–3.80)) also had a higher likelihood of infection. This report highlights that a sustained availability of personal protective equipment limits the SARS-CoV-2 infection rate to what is measured in the general population. It also pinpoints the need for dedicated hygiene training among young professionals, justifies the systematic eviction of infected personnel, and stresses the need for interventions to increase vaccination coverage among any healthcare workers. Full article