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measurements. To address this, we conducted a two-year study using large lysimeters in an ecotron facility, continuously measuring ecosystem-level CO 2 , N 2 O, and H 2 O fluxes. We investigated the impact of endogeic and anecic earthworms on GHG emissions and ecosystem water use efficiency (WUE) in an agricultural setting. Although we observed transient stimulations of carbon fluxes in the presence of earthworms, cumulative fluxes over the study indicated no significant increase in CO 2 emissions. Endogeic earthworms marginally reduced N 2 O emissions during the wheat culture (-44.6%), but this effect was not sustained throughout the experiment. No consistent effects on ecosystem evapotranspiration or WUE were found. Our study suggests that earthworms do not significantly contribute to GHG emissions over a two-year period in experimental conditions that mimic an agricultural setting. These findings highlight the need for realistic experiments enabling continuous GHG measurements.

The isotopic composition of dioxygen in the atmosphere is a global tracer which depends on the biosphere flux of dioxygen toward and from the atmosphere (photosynthesis and respiration) as well as exchanges with the stratosphere. When measured in fossil air trapped in ice cores, the relative concentration of 16O, 17O, and 18O of O2 can be used for several applications such as ice core dating and past global productivity reconstruction. However, there are still uncertainties about the accuracy of these tracers as they depend on the integrated isotopic discrimination of different biological processes of dioxygen production and uptake, for which we currently have very few independent estimates. Here we determined the respiration and photosynthesis fractionation factors for atmospheric dioxygen from experiments carried out in a replicated vegetation–soil–atmosphere analogue of the terrestrial biosphere in closed chambers with growing Festuca arundinacea. The values for 18O discrimination during soil respiration and dark respiration in leaves are equal to -12.3±1.7 ‰ and -19.1±2.4 ‰, respectively. In these closed biological chambers, we also found a value attributed to terrestrial photosynthetic isotopic discrimination equal to +3.7±1.3 ‰. This last estimate suggests that the contribution of terrestrial productivity in the Dole effect may have been underestimated in previous studies.

The triple oxygen isotope composition of phytoliths (17O-excessphyto) can provide key information on past atmospheric relative humidity (RH) over land. Here, we examined how leaf-to-air temperature gradients and changes in the silica polymerization rate in response to stomatal conductance influence the interpretation of 17O-excessphyto in terms of RH. Further, we assessed the reliability of a theoretical isotope model of leaf water evaporation to predict the triple oxygen isotope composition of leaf water on diurnal and seasonal scale. For this purpose, we monitored a grass plot within a natural Mediterranean woodland for one year. We measured in particular the isotope composition of atmospheric water vapor and plot-scale grass leaf temperatures – two variables that are often only estimated. Grass leaf blades were collected in different seasons and over a 24-hour period for leaf water and phytolith isotope analysis. We found that the steady state model reliably predicts the triple oxygen isotope composition of leaf water during daytime but remains sensitive to uncertainties on the leaf-to-air temperature difference. Deviations from isotope steady state at night are well represented by the non-steady state model. In our study, the 17O-excessphyto best reflects average daytime RH over the growth period, rather than daily RH. Average daytime leaf-to-air temperature gradients of less than 2 °C introduce an insignificant bias to the RH estimate. The results also confirm the established triple oxygen isotope fractionation factors between phytoliths and leaf water. The findings of this study help to better understand how to interpret 17O-excessphyto of fossil phytolith assemblages in terms of past RH.

Ecosystems integrity and services are threatened by anthropogenic global changes. Mitigating and adapting to these changes require knowledge of ecosystem functioning in the expected novel environments, informed in large part through experimentation and modelling. This paper describes 13 advanced controlled environment facilities for experimental ecosystem studies, herein termed ecotrons, open to the international community. Ecotrons enable simulation of a wide range of natural environmental conditions in replicated and independent experimental units while measuring various ecosystem processes. This capacity to realistically control ecosystem environments is used to emulate a variety of climatic scenarios and soil conditions, in natural sunlight or through broad‐spectrum lighting. The use of large ecosystem samples, intact or reconstructed, minimizes border effects and increases biological and physical complexity. Measurements of concentrations of greenhouse trace gases as well as their net exchange between the ecosystem and the atmosphere are performed in most ecotrons, often quasi continuously. The flow of matter is often tracked with the use of stable isotope tracers of carbon and other elements. Equipment is available for measurements of soil water status as well as root and canopy growth. The experiments ran so far emphasize the diversity of the hosted research. Half of them concern global changes, often with a manipulation of more than one driver. About a quarter deal with the impact of biodiversity loss on ecosystem functioning and one quarter with ecosystem or plant physiology. We discuss how the methodology for environmental simulation and process measurements, especially in soil, can be improved and stress the need to establish stronger links with modelling in future projects. These developments will enable further improvements in mechanistic understanding and predictive capacity of ecotron research which will play, in complementarity with field experimentation and monitoring, a crucial role in exploring the ecosystem consequences of environmental changes., Experimentation and modelling are necessary to predict ecosystem functioning under future environments and to develop mitigating and adapting strategies. This paper describes 13 advanced controlled environment facilities, called ecotrons, open to the international community. An ecotron comprises a set of replicated enclosures designed to host ecosystems samples and enable realistic simulations of above‐ and belowground environmental conditions, while simultaneously and automatically measuring ecosystem processes. The characteristics of these infrastructures are given as well as examples of collaborative projects hosted so far.

RATIONALE Producing robust high frequency time series of raw atmospheric water vapor isotope data by laser spectrometry requires accurate calibration. Especially, the chemical composition of the analyzed sample gas can cause isotope bias. This study assesses the matrix effect on calibrated δ17 O, δ18 O, δ2 H, 17 O-excess, and d-excess values of atmospheric water vapor. METHODS A Picarro L2140-i cavity ring-down spectrometer combined with an autosampler and a vaporizer is used to analyze δ17 O, δ18 O, δ2 H, 17 O-excess and d-excess of two water standards. Isotope data obtained using synthetic air and dry ambient air as carrier gas at water mixing ratios ranging from 2000 to 30000 ppmv are compared. Based on the results, atmospheric water vapor measurements are calibrated. The expected precision is estimated by Monte Carlo simulation. RESULTS The dry air source strongly impacts raw isotope values of the two water standards, but has no effect on the mixing ratio dependency functions. When using synthetic air, δ17 O, δ18 O and 17 O-excess of calibrated atmospheric water vapor are overestimated by 0.6 ‰, 0.7 ‰, and 217 per meg, respectively, while δ2 H and d-excess are underestimated by 1.5 ‰ and 7.3 ‰. Optimum precisions for the calibrated δ17 O, δ18 O, δ2 H, 17 O-excess and d-excess values and 12-min integration time are 0.02 ‰, 0.03 ‰, 0.4 ‰, 14 per meg and 0.4 ‰, respectively. CONCLUSIONS In light of the obtained results, recommendations for the calibration of atmospheric water vapor isotope measurements are presented. The necessity to use dry ambient air as dry air source when running the standards for calibration is pointed out as a pre-requisite for accurate atmospheric water vapor 17 O-excess and d-excess measurements.

Sarcomas are a heterogeneous group of tumors whose incidence is nearly 5 per 100 000 inhabitants in Europe. Their causes are poorly understood, although occupational exposures (especially farming and pesticides) are suspected. The AGRICAN cohort is a prospective study of 181 842 individuals enrolled in 2005 to 2007 who completed an enrolment questionnaire with data on lifelong agricultural exposure. Associations between agricultural exposure and sarcoma overall, gastrointestinal stromal tumors (GIST) and myomatous and fibrous sarcoma together, were analyzed with a Cox model. Until 2015, 188 incident cases of sarcoma were identified. Increased risks were observed (a) among cattle farmers working10 years (HR

International audience; IntroductionAs part of an analysis on the extension of the HPV vaccination to French boys, the French National Cancer Institute (INCa) and the French National Authority for Health (HAS) have conducted in collaboration a survey on HPV vaccine acceptance in July 2019. This survey was completed by parents of children aged 11–19 and general practitioners (GPs). Questions focused on their representations, practices and intentions in the context of the future policy change allowing boys to get vaccinated against HPV.MethodsThe survey was conducted between June 20 and July 12, 2019. It focused on two populations: a nationally representative sample of parents with at least one girl aged 11–19 and/or one boy aged 11–14 (n = 1984) and a representative sample of GPs in mainland France. Data were collected through a web-based questionnaire with a mean completion time of 10 minutes for parents and GPs. The quota method was applied to ensure the representative nature of the samples based on (i) gender, age, children (girl aged 11–14 and/or boy aged 11–14) of the household, socio-professional category of the “head of the household”, size of urban area and region for the parents’ sample and based on (ii) gender, age, region and type of practice for the GPs’ sample.ResultsAlthough most GPs were very favourable towards HPV vaccination (94%), they considered it one of the most challenging vaccinations to get parents to adhere to (82%). A notable percentage of parents have unfavourable opinions towards HPV vaccination (25%). The three main barriers cited by parents of non-vaccinated girls were: the fear of adverse effects, the lack of information, and the fact that the GP did not propose it. Regarding the extension of HPV vaccination to boys, 84 % of GPs would recommend this vaccination to boys if it was included in the vaccination schedule, and 88 % of those who did not routinely recommend HPV vaccination to girls would be more likely to offer it to girls if the extension was recommended.; IntroductionDans le cadre des travaux de 2019 de la HAS portant sur l’extension de la vaccination contre les papillomavirus humains (HPV) aux garçons, l’INCa et la HAS ont réalisé une enquête en juillet 2019 portant sur l’acceptabilité de la vaccination contre les HPV. Cette étude a été réalisée auprès de parents ayant des enfants de onze à dix-neuf ans et de médecins généralistes. Elle a porté sur leurs représentations, leurs pratiques, ainsi que leurs intentions dans la perspective de l’élargissement de la vaccination contre les HPV aux garçons.MéthodeL’enquête a été menée entre le 20 juin et le 12 juillet 2019, auprès de deux publics : un échantillon national représentatif des parents ayant au moins une fille de onze à dix-neuf ans et/ou un garçon de onze à quatorze ans (n = 1984) dans leur foyer et un échantillon représentatif de 300 médecins généralistes libéraux exerçant en France métropolitaine. Les données de l’enquête ont été recueillies par le biais d’un questionnaire en ligne dont la durée moyenne de passation était de dix minutes. La construction des échantillons a été réalisée selon la méthode des quotas appliquée aux variables suivantes : (i) pour les parents : sexe, âge, enfant dans le foyer (fille de onze à dix-neuf ans et/ou garçon de onze à quatorze ans), catégorie socioprofessionnelle (CSP) du référent du ménage, catégorie d’agglomération et région ; et (ii) pour les médecins généralistes : mode d’exercice (libéral/mixte), genre, âge et région.RésultatsBien que les médecins généralistes fussent très favorables à la vaccination contre les HPV (94 %), une majorité d’entre eux (82 %) considéraient qu’il s’agissait de l’une des vaccinations les plus difficiles à faire accepter à leurs patients. Une part importante des parents était défavorable à la vaccination contre les HPV (25 %). Les trois principaux freins cités par les parents de filles non vaccinées étaient : la crainte d’effets secondaires, le manque d’information et le fait que le médecin ne l’ait pas proposé. En ce qui concerne l’élargissement de la vaccination aux garçons, 84 % des médecins généralistes déclaraient qu’ils recommanderaient la vaccination aux garçons dès lors qu’elle serait intégrée au calendrier vaccinal et 88 % de ceux qui ne la recommandaient pas systématiquement aux filles déclaraient qu’ils seraient plus enclins à la proposer aux filles si l’extension était recommandée.

International audience

High precision measurements of triple isotopic composition of oxygen in the air trapped in ice cores is a useful tool to infer the global gross biosphere productivity in the past. The isotopic composition of oxygen is influenced by many physical, chemical and biological processes during consumption and production of oxygen by the oceanic and terrestrial biosphere. For an accurate quantification of the past biosphere productivity, it is thus important to determine the different fractionation processes occurring in the biosphere during respiration and photosynthesis processes.We present here quantification of fractionation coefficients associated with δ180 and the D170 of 02 during respiration and photosynthesis within the terrestrial biosphere. The experimental set-up relies on closed biological chambers in which all the environmental parameters are controlled and measured. Triple isotopic composition of oxygen is regularly measured through sampling of small aliquots at a low frequency (4 h to 4 days). Seven 2-month long experiments were performed in order to check the reproducibility of our set-up and quantify uncertainty on the determination of the fractionation coefficients.In order to improve our set-up for future experiments using different plants, we also present perspectives for a continuous measurement of the isotopic composition of oxygen using optical spectroscopy (Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) technique). This instrument is currently being characterized and we will present its current performances.Triple isotopic composition of oxygen in the atmospheric dioxygen to reconstruct the dynamic of global biosphere productivity in the past from measurements in biological chambers.