deadtrees.earth — An open-access and interactive database for centimeter-scale aerial imagery to uncover global tree mortality dynamics

Excessive tree mortality is a global concern and remains poorly understood as it is a complex phenomenon. We lack global and temporally continuous coverage on tree mortality data. Ground-based observations on tree mortality, e.g., derived from national inventories, are very sparse, and may not be standardized or spatially explicit. Earth observation data, combined with supervised machine learning, offer a promising approach to map overstory tree mortality in a consistent manner over space and time. However, global-scale machine learning requires broad training data covering a wide range of environmental settings and forest types. Low altitude observation platforms (e.g., drones or airplanes) provide a cost-effective source of training data by capturing high-resolution orthophotos of overstory tree mortality events at centimeter-scale resolution. Here, we introduce deadtrees.earth, an open-access platform hosting more than two thousand centimeter-resolution orthophotos, covering more than 1,000,000 ha, of which more than 58,000 ha are manually annotated with live/dead tree classifications. This community-sourced and rigorously curated dataset can serve as a comprehensive reference dataset to uncover tree mortality patterns from local to global scales using space-based Earth observation data and machine learning models. This will provide the basis to attribute tree mortality patterns to environmental changes or project tree mortality dynamics to the future. The open nature of deadtrees.earth, together with its curation of high-quality, spatially representative, and ecologically diverse data will continuously increase our capacity to uncover and understand tree mortality dynamics

Comparison of Coliforms and Coliphages as Tools for Assessment of Viral Contamination in River Water

The aim of the study was to evaluate the presence of pathogenic viruses in the Moselle River and to compare the usefulness of thermotolerant coliforms and somatic coliphages as tools for river water quality assessment in terms of viral contamination. Thermotolerant coliforms and somatic coliphages were enumerated by standardized methods in 170 samples of river water drawn from five sampling sites along the Moselle River (eastern France). BGM cell culture and integrated cell culture-reverse transcription-PCR DNA enzyme immunoassay were used to determine the presence of pathogenic viral genome (Enterovirus and Norovirus genogroup II [GGII]) and infectious Enterovirus spp. in 90 1-liter samples. No infectious Enterovirus spp. were isolated, but Enterovirus and Norovirus GGII genomes were detected in 38% of the samples. Norovirus GGII genome was mostly detected in winter, whereas Enterovirus genome was mostly detected in summer and fall. Somatic coliphages appeared to be less sensitive to higher river water temperature than thermotolerant coliforms. Furthermore, the number of river water samples positive for pathogenic viral genome increased with increasing concentration of somatic coliphages, whereas coliform concentration was unrelated to viral genome contamination. Consequently somatic coliphages, which are less sensitive to environmental factors than thermotolerant coliforms in river water, would provide a promising tool for assessment of river water quality in terms of fecal and viral pollution

Survival of infectious Poliovirus-1 in river water compared to the persistence of somatic coliphages, thermotolerant coliforms and Poliovirus-1 genome

International audienceThe microbiological quality of water is currently assessed by search for fecal bacteria indicators. There is, however, a body of knowledge demonstrating that bacterial indicators are less resistant to environmental factors than human pathogenic viruses and therefore underestimate the viral risk. As river water is often used as a resource for drinking water production, it is particularly important to obtain a valid estimation of the health hazard, including specific viral risk. This work was conducted to compare the survival of infectious Poliovirus-1 used as a pathogenic virus model to the persistence of, on the one hand, thermotolerant coliforms commonly used as indicators and on the other hand, to somatic coliphages and Poliovirus-1 genome considered as potential indicators. We studied the behavior of infectious Poliovirus-1 and the three (potential) indicators of viral contamination in river water at three different temperatures (4°C,18°C and 25°C). This experiment was performed twice with river water sampled at two different periods, once in winter and once in summer. Our results showed that the survival of thermotolerant coliforms can be 1.5-fold lower than infectious Poliovirus-1. In contrast, under all our experimental conditions, somatic coliphages and Poliovirus-1 genome persisted longer than infectious Poliovirus-1, surviving, respectively, 2–6-fold and about 2-fold longer than infectious Poliovirus-1. According to our results exclusively based on survival capacity, somatic coliphages and viral genome, unlike thermotolerant coliforms appear to be better indicators of viral contamination in river water. Moreover, the disappearance of viral genome is well-correlated to that one of infectious virus irrespective of the conditions tested

Cu surface fonctionnalisation using Quasi insitu XPS analyses for PEALD Self Assembly Monolayers (SAM) 300mm process développent

International audienc

Etude par XPS quasi insitu de la fonctionnalisation de la surface du cuivre par des monocouches auto-assemblées (SAM)

International audienc

Recovery of feline calicivirus infectious particles and genome from water: comparison of two concentration techniques

The aim of this work was to determine the recovery rate of feline calicivirus (FCV-F9) infectious particles and genome from water after a concentration step using either adsorption elution on glass wool or filtration through an electropositive membrane. The results showed that the membrane filtration technique allowed a 75% recovery rate of FCV-F9 infectious particles while the yield was only 5.3% for FCV-F9 genome. Using the glass wool adsorption-elution technique, the recovery rate of FCV-F9 infectious particles was 0.5% while the yield was 102.5% with Poliovirus 1.</jats:p

Etude par XPS quasi insitu de la fonctionnalisation de la surface du cuivre par des monocouches auto-assemblées (SAM)

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Development of a viral concentration method for bottled water stored in hydrophobic support

International audienceSeveral protocols have been described for the detection of genomes of enteric viruses from water using two-step procedures: membrane filtration and RT-PCR detection. However, these methods, when applied to bottled water, generally consider only the aqueous phase. Such procedures do not take into account the adhesion of viruses onto the hydrophobic container. Potential adhesion results in loss of viral concentration in the aqueous phase and consequently viral pollution is underestimated in such a system. A procedure based on the addition of surfactant to elute viruses followed by membrane concentration was developed to avoid this underestimation. Firstly, using poliovirus 1 as a model, this study demonstrated that the best solution to recover virus and/or viral genome is a mix of sodium dodecyl sulphate, a nonionic detergent and guanidine thiocyanate. Furthermore, temperature has a significant but low effect on elution. A positively charged 0.2 μm inorganic membrane composed of Alumina (Anodisc, Whatman) is also the best membrane to concentrate viral material before the detection by RT-PCR. Finally, the developed protocol gives significantly higher poliovirus 1 recovery rate than a reference protocol previously described (aqueous phase concentration on Zetapore). The difference can be explained by the recovery of the viruses adsorbed onto the water container

Cu surface fonctionnalisation using Quasi insitu XPS analyses for PEALD Self Assembly Monolayers (SAM) 300mm process développent

International audienc