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We have derived values of the Ultraviolet Index (UVI) at solar noon using the Tropospheric Ultraviolet Model (TUV) driven by ozone, temperature and aerosol fields from climate simulations of the first phase of the Chemistry-Climate Model Initiative (CCMI-1). Since clouds remain one of the largest uncertainties in climate projections, we simulated only the clear-sky UVI. We compared the modelled UVI climatologies against present-day climatological values of UVI derived from both satellite data (the OMI-Aura OMUVBd product) and ground-based measurements (from the NDACC network). Depending on the region, relative differences between the UVI obtained from CCMI/TUV calculations and the ground-based measurements ranged between −5.9% and 10.6%. We then calculated the UVI evolution throughout the 21st century for the four Representative Concentration Pathways (RCPs 2.6, 4.5, 6.0 and 8.5). Compared to 1960s values, we found an average increase in the UVI in 2100 (of 2–4%) in the tropical belt (30°N-30°S). For the mid-latitudes, we observed a 1.8 to 3.4 % increase in the Southern Hemisphere for RCP 2.6, 4.5 and 6.0, and found a 2.3% decrease in RCP 8.5. Higher increases in UVI are projected in the Northern Hemisphere except for RCP 8.5. At high latitudes, ozone recovery is well identified and induces a complete return of mean UVI levels to 1960 values for RCP 8.5 in the Southern Hemisphere. In the Northern Hemisphere, UVI levels in 2100 are higher by 0.5 to 5.5% for RCP 2.6, 4.5 and 6.0 and they are lower by 7.9% for RCP 8.5. We analysed the impacts of greenhouse gases (GHGs) and ozone-depleting substances (ODSs) on UVI from 1960 by comparing CCMI sensitivity simulations (1960–2100) with fixed GHGs or ODSs at their respective 1960 levels. As expected with ODS fixed at their 1960 levels, there is no large decrease in ozone levels and consequently no sudden increase in UVI levels. With fixed GHG, we observed a delayed return of ozone to 1960 values, with a corresponding pattern of change observed on UVI, and looking at the UVI difference between 2090s values and 1960s values, we found an 8 % increase in the tropical belt during the summer of each hemisphere. Finally we show that, while in the Southern Hemisphere the UVI is mainly driven by total ozone column, in the Northern Hemisphere both total ozone column and aerosol optical depth drive UVI levels, with aerosol optical depth having twice as much influence on the UVI as total ozone column does.

We present preliminary results on a study of the 2--850 micron SEDs of a sample of 30 FIRBACK galaxies selected at 170 micron. These sources are representative of the brightest ~10% of the Cosmic Infrared Background. They are a mixture of mostly local (z<~0.3) starforming galaxies, and a tail of ULIGs that extend up to z~1, and are likely to be a similar population to faint SCUBA sources. We use archival Spitzer IRAC and MIPS data to extend the spectral coverage to the mid-IR regime, resulting in an unprecended (for this redshift range) census of their infrared SEDs. This allows us to study in far greater detail this important population linking the near-IR stellar emission with PAH and thermal dust emission. We do this using a Markov Chain Monte Carlo method, which easily allows for the inclusion of ~6 free parameters, as well as an estimate of parameter uncertainties and correlations. Comment: 5 pages, 3 figures. Proceeding for the conference "Starbursts: From 30 Doradus to Lyman Break Galaxies", held in Cambridge (UK) in September, 2004

Avec la crise du coronavirus, les destinations lointaines de nature comme la Patagonie chilienne sont inquiètes d’un effondrement du tourisme. Les communautés locales, apeurées par les risques liés à l’accueil de visiteurs, se replient et se protègent. Les entrepreneurs espèrent un rapide retour à la « normalité » d’une zone relativement épargnée par la COVID-19, mais craignent la fin du boom touristique, car prendre l’avion restera anxiogène dans un contexte de pandémie. Ces destinations devraient recentrer leur offre afin de capter une clientèle de proximité, mais cela semble un défi peu rentable pour les zones isolées. Alors que les entrepreneurs affinent leur plan marketing et les services d’État leurs protocoles d’accueil sécurisés, les animateurs de projets touristiques écologiques, axés sur la conservation, le tourisme rural et les migrations d’agrément, font valoir leurs atouts. L’actuelle crise pourrait mettre fin au tourisme de masse, à l’hypermobilité vers des hauts lieux et aux projets basés sur la rentabilité. La crise socioenvironnementale globale est l’occasion de repenser les rapports à la nature et de renforcer les systèmes touristiques locaux, pensés comme des lieux de vie, basés sur des économies rurales respectueuses de l’environnement, les échanges culturels, scientifiques et traditionnels, attirants autant pour les clientèles nationales qu’étrangères. With the coronavirus crisis, remote nature destinations like Chilean Patagonia are worried of a possible collapse of tourism. Local communities, frightened by the risks of welcoming visitors, are withdrawing and protecting themselves. Entrepreneurs hope for a rapid return to “normality” in an area relatively untouched by COVID-19 but they fear the end of the tourism boom, as flying will remain an anxiety-provoking issue in a post-pandemic situation. These destinations have to refocus their offer in order to capture a national clientele, but this seems an unprofitable challenge for isolated areas. While entrepreneurs are refining their marketing plans and government services are establishing their secure reception protocols, leaders of ecological and conservation tourism projects along with rural tourism and leisure migration stakeholders are highlighting their assets. The current crisis could put an end to mass tourism, hypermobilities, projects based on high profitability and overtourism in iconic places. In that sense, the present global socioenvironmental crisis is an opportunity to rethink our relationship with nature and seek ways to strengthen local tourism systems, conceived as places to live and based on environmentally friendly rural economies, cultural, scientific, and traditional exchanges, attractive both to national and foreign visitors.

The evolution of massive stars is still partly unconstrained. Mass, metallicity, mass loss and rotation are the main drivers of stellar evolution. Binarity and magnetic field may also significantly affect the fate of massive stars. Our goal is to investigate the evolution of single O stars in the Galaxy. For that, we use a sample of 74 objects comprising all luminosity classes and spectral types from O4 to O9.7. We rely on optical spectroscopy obtained in the context of the MiMeS survey of massive stars. We perform spectral modelling with the code CMFGEN. We determine the surface properties of the sample stars, with special emphasis on abundances of carbon, nitrogen and oxygen. Most of our sample stars have initial masses in the range 20 to 50 Msun. We show that nitrogen is more enriched and carbon/oxygen more depleted in supergiants than in dwarfs, with giants showing intermediate degrees of mixing. CNO abundances are observed in the range of values predicted by nucleosynthesis through the CNO cycle. More massive stars, within a given luminosity class, appear to be more chemically enriched than lower mass stars. We compare our results with predictions of three types of evolutionary models and show that, for two sets of models, 80% of our sample can be explained by stellar evolution including rotation. The effect of magnetism on surface abundances is unconstrained. Our study indicates that, in the 20-50 Msun mass range, the surface chemical abundances of most single O stars in the Galaxy are fairly well accounted for by stellar evolution of rotating stars. Comment: 15 pages, 12 figures. Accepted in Astronomy & Astrophysics

International audience; In this Article, we report a simple and effective method to build up self-assembled and well-calibrated layers of plasmid DNA*1,3-diaminopropane complexes onto highly oriented pyrolitic graphite (HOPG). The method is based on the self-assembly of the poly electrolytes onto HOPG in an excess of positively charged protonated diamines (Dap2+) in comparison to the negatively charged phosphate moieties of the DNA backbone in solution. Although short distortions in the helical parameters of DNA (maximum 12% hypochromicity) are revealed by UV-vis absorption spectrometry, the native B form of the plasmids is conserved. By fixing the excess of positive charges arising from Dap2+ cations, it is possible to construct assemblies of a well-defined thickness ranging typically from 1 monolayer (ML) of DNA to 10 ML; 1 ML has a thickness of 2.2 ± 0.5 nm. Adding TRIS-EDTA (TE) buffer lowers considerably the damage rate observed when plasmids are mixed with Dap2+ in pure water. The thickness of the first dense monolayer matches well the DNA cross-sectional dimensions, indicating that this layer is strongly anchored to the surface; it is insoluble in water. Conversely, thicker layers can be released in aqueous media, and the plasmids do not undergo dramatic damage. In the presence of TE buffer, condensation of the plasmids on the HOPG surface and a further release of the deposits in water yields a loss of supercoiling that ranges typically from 10% to 20% when the layer thickness varies from 22 to 12 nm. Such densely packed and releasable DNA plasmid layers with a very well-characterized and constant thickness constitute a substantial progress for biochemical and radiochemical experiments.

We present observations with the planet finder Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) of a selected sample of the most promising radial velocity (RV) companions for high-contrast imaging. Using a Monte Carlo simulation to explore all the possible inclinations of the orbit of wide RV companions, we identified the systems with companions that could potentially be detected with SPHERE. We found the most favourable RV systems to observe are: HD 142, GJ 676, HD 39091, HIP 70849, and HD 30177 and carried out observations of these systems during SPHERE Guaranteed Time Observing. To reduce the intensity of the starlight and reveal faint companions, we used principal component analysis algorithms alongside angular and spectral differential imaging. We injected synthetic planets with known flux to evaluate the self-subtraction caused by our data reduction and to determine the 5σ contrast in the J band versus separation for our reduced images. We estimated the upper limit on detectable companion mass around the selected stars from the contrast plot obtained from our data reduction. Although our observations enabled contrasts larger than 15 mag at a few tenths of arcsec from the host stars, we detected no planets. However, we were able to set upper mass limits around the stars using AMES-COND evolutionary models. We can exclude the presence of companions more massive than 25–28 MJup around these stars, confirming the substellar nature of these RV companions. Monthly Notices of the Royal Astronomical Society, 480 (1) ISSN:0035-8711 ISSN:1365-2966

International audience; Although bone formation around and within implants has been intensively studied, the role of pores and pore geometry is still debated. Notwithstanding studies reporting the formation of bone and bone components within pores as small as a few micrometers ('micropores'), bone ingrowth is believed to only occur in pores larger than 100 mu m ('macropores'). A thorough analysis of 10 different porous beta-tricalcium phosphate cylinders (empty set: 8 mm; L: 13 mm) implanted for 2-24 weeks in an ovine model demonstrates ingrowth of mineralized tissue (MT) in pores as small as 1 mu m. This tissue contained calcium phosphate, collagen, and interconnected cells. It formed within the first 3-4 weeks of implantation, extended over several hundred micrometers within the ceramic, and contributed to the majority of the early MT formation (including bone) in the defect. The indentation stiffness of the MT-ceramic composite was significantly higher than that of bone and MT-free ceramic. The presented results substantiate the importance of micropores for optimal bone healing, particularly at early implantation times