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The Ophiuchus stream is a short arc-like stellar feature of uncertain origin located $\sim 5$ kpc North of the Galactic centre. New proper motions from the second $Gaia$ data release reconcile the direction of motion of stream members with the stream arc, resolving a puzzling mismatch reported in earlier work. We use N-body simulations to show that the stream is likely only on its second pericentric passage, and thus was formed recently. The simulations suggest that the entire disrupted progenitor is visible in the observed stream today, and that little further tidal debris lies beyond the ends of the stream. The luminosity, length, width, and velocity dispersion of the stream suggest a globular cluster (GC) progenitor substantially fainter and of lower surface brightness than estimated in previous work, and unlike any other known globulars in the Galaxy. This result suggests the existence of clusters that would extend the known GC population to fainter and more weakly bound systems than hitherto known. How such a weakly-bound cluster of old stars survived until it was disrupted so recently, however, remains a mystery. Integrating backwards in time, we find that the orbits of Sagittarius and Ophiuchus passed within $\sim 5$ kpc of each other about $\sim 100$ Myrs ago, an interaction that might help resolve this puzzle. Comment: 11 pages, 7 figures, submitted to MNRAS

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.

The infant brain undergoes a remarkable period of neural development that is crucial for the development of cognitive and behavioral capacities (Hasegawa et al., 2018). Longitudinal magnetic resonance imaging (MRI) is able to characterize the developmental trajectories and is critical in neuroimaging studies of early brain development. However, missing data at different time points is an unavoidable occurrence in longitudinal studies owing to participant attrition and scan failure. Compared to dropping incomplete data, data imputation is considered a better solution to address such missing data in order to preserve all available samples. In this paper, we adapt generative adversarial networks (GAN) to a new application: longitudinal image prediction of structural MRI in the first year of life. In contrast to existing medical image-to-image translation applications of GANs, where inputs and outputs share a very close anatomical structure, our task is more challenging as brain size, shape and tissue contrast vary significantly between the input data and the predicted data. Several improvements over existing GAN approaches are proposed to address these challenges in our task. To enhance the realism, crispness, and accuracy of the predicted images, we incorporate both a traditional voxel-wise reconstruction loss as well as a perceptual loss term into the adversarial learning scheme. As the differing contrast changes in T1w and T2w MR images in the first year of life, we incorporate multi-contrast images leading to our proposed 3D multi-contrast perceptual adversarial network (MPGAN). Extensive evaluations are performed to assess the qualityand fidelity of the predicted images, including qualitative and quantitative assessments of the image appearance, as well as quantitative assessment on two segmentation tasks. Our experimental results show that our MPGAN is an effective solution for longitudinal MR image data imputation in the infant brain. We further apply our predicted/imputed images to two practical tasks, a regression task and a classification task, in order to highlight the enhanced task-related performance following image imputation. The results show that the model performance in both tasks is improved by including the additional imputed data, demonstrating the usability of the predicted images generated from our approach.

Climate warming and related drivers of soil thermal change in the Arctic are expected to modify the distribution and dynamics of carbon contained in perennially frozen grounds. Thawing of permafrost in the Mackenzie Delta region of northwestern Canada, coupled with increases in river discharge and coastal erosion, trigger the release of terrestrial organic matter (OMt) from the largest Arctic drainage basin in North America into the Arctic Ocean. While this process is ongoing, well-established, and its rate is accelerating, the fate of the newly-mobilized organic matter, as it transits from the watershed through the delta and into the marine system, remains poorly understood. In the framework of the European Horizon 2020 Nunataryuk programme, and as part of the Work Package 4 (WP4) Coastal Waters theme, four field expeditions were conducted in the Mackenzie Delta region and southern Beaufort Sea from April to September 2019. The temporal sampling design allowed the survey of ambient conditions in the coastal waters under full ice cover prior to the spring freshet, during ice break-up in summer, as well as anterior to the freeze-up period in fall. To capture the fluvial-marine transition zone, and with distinct challenges related to shallow waters and changing seasonal and meteorological conditions, the field sampling was conducted in close partnership with members of the communities of Aklavik, Inuvik and Tuktoyaktuk, using several platforms: helicopters, snowmobiles and small boats. Water column profiles of physical and optical variables were measured in situ, while surface water, groundwater and sediment samples were collected and preserved for the determination of the composition and sources of OMt, including particulate and dissolved organic carbon (POC, DOC), and chromophoric dissolved organic matter (CDOM), as well as a suite of physical, chemical and biological variables. Here we present an overview of the standardized datasets, including hydrographic profiles, remote sensing reflectance, temperature and salinity, particle absorption, nutrients, dissolved organic carbon, particulate organic carbon, particulate organic nitrogen, colored dissolved organic matter absorption, fluorescent dissolved organic matter intensity, suspended particulate matter, total particulate carbon, total particulate nitrogen, stable water isotopes, radon in water, bacterial abundance, and a string of phytoplankton pigments including total chlorophyll. Datasets and related metadata can be found in Juhls et al. 2021. https://doi.pangaea.de/10.1594/PANGAEA.937587.

Grape seeds are considered one of the most important sources for phenolic and other compounds and is globally consumed for the biological value of its active ingredients. The increasing prevalence of Methicillin-resistant Staphylococcus aureus-related infections has become a very challenging health issue worldwide. This work aims at examining the antibacterial activity of alcoholic extract of black grape seeds (Vitis vinifera) against biofilm formation by Staphylococcus aureus and Staphylococcus haemolyticus. Staphylococcal bacterial isolates were first clinically confirmed using the VITEK-2compact system (ID and AST), and four isolates were selected depending on virulence and resistance to different types of antibiotics. The ability of S. aureus and S. haemolyticus isolates to form biofilm was examined using a standardized 96-well microtiter plate method. Furthermore, the effect of Moxifloxacin and Penicillin G with MIC, sub-MIC and sub-sub-MIC in preventing S. aureus and S. haemolyticus biofilm production, as well as that of the grape seed extract (180 mg/ml) were tested against biofilm formation. Our data indicate that all of the Staphylococcal bacterial isolates were able to produce biofilm which was prevented by the methanolic extracts of the crude seeds of Vitis vinifera rich in galloylated catechin esters of gallic acid. A significant (P < 0.001) synergistic effect between Penicillin G, Moxifloxacin with MIC, sub-MIC and sub-sub-MIC and that of the methanolic extract of Vitis vinifera (180 mg/ml) against bacterial biofilm formation was also detected. This report confirms the antibacterial activity of the methanolic extract of the black grape seeds.

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.