A data science challenge for converting airborne remote sensing data into ecological information

Ecology has reached the point where data science competitions, in which multiple groups solve the same problem using the same data by different methods, will be productive for advancing quantitative methods for tasks such as species identification from remote sensing images. We ran a competition to help improve three tasks that are central to converting images into information on individual trees: (1) crown segmentation, for identifying the location and size of individual trees; (2) alignment, to match ground truthed trees with remote sensing; and (3) species classification of individual trees. Six teams (composed of 16 individual participants) submitted predictions for one or more tasks. The crown segmentation task proved to be the most challenging, with the highest-performing algorithm yielding only 34% overlap between remotely sensed crowns and the ground truthed trees. However, most algorithms performed better on large trees. For the alignment task, an algorithm based on minimizing the difference, in terms of both position and tree size, between ground truthed and remotely sensed crowns yielded a perfect alignment. In hindsight, this task was over simplified by only including targeted trees instead of all possible remotely sensed crowns. Several algorithms performed well for species classification, with the highest-performing algorithm correctly classifying 92% of individuals and performing well on both common and rare species. Comparisons of results across algorithms provided a number of insights for improving the overall accuracy in extracting ecological information from remote sensing. Our experience suggests that this kind of competition can benefit methods development in ecology and biology more broadly

Morphologies

Séminaire commun avec la participation de : Olivier Abel, Luciano Boi, Jean-Claude Bonne, Marion Carel, Giovanni Careri, Enrico Castelli Gattinara, Patrice Ceccarini, Ryozo Hiyama, Georges Didi-Huberman, Maurizio Gribaudi, Bernard Jaulin, Gérard Jorland, Farhad Khosrokhavar, Hervé Le Bras, Giovanni Levi, Sabina Loriga, Silvia Mancini, Zacarías Moutoukias, Jean Petitot, Pierre Rosenstiehl, Carlo Severi, Irène Tamba, Lorraine Verner, Wiktor Stoczkowski Compte rendu non communiqué

Morphologies

Séminaire commun avec la participation de : Olivier Abel, Luciano Boi, Jean-Claude Bonne, Marion Carel, Giovanni Careri, Enrico Castelli Gattinara, Patrice Ceccarini, Danièle Cohn, Georges Didi-Huberman, Fernando Gil, Maurizio Gribaudi, Ryozo Hiyama, Bernard Jaulin, Gérard Jorland, Farhad Khosrokhavar, Hervé Le Bras, Giovanni Levi, Sabina Loriga, Silvia Mancini, Jean Petitot, Pierre Rosenstiehl, Carlo Severi, Wiktor Stoczkowski, Lorraine Verner Compte rendu non communiqué

Morphologies

Séminaire commun avec la participation d’Olivier Abel, Luciano Boi, Jean-Claude Bonne, Marion Carel, Giovanni Careri, Enrico Castelli Gattinara, Patrice Ceccarini, Danièle Cohn, Ryozo Hiyama, Georges Didi-Huberman, Fernando Gil, Maurizio Gribaudi, Bernard Jaulin, Farhad Khosrokhavar, Hervé Le Bras, Giovanni Levi, Sabina Loriga, Silvia Mancini, Zacarias Moutoukias, Jean Petitot, Pierre Rosenstiehl, Carlo Severi, Lorraine Verner, Wiktor Stoczkowski Voici, les différents sujets abordés et discut..

PML/RARA oxidation and arsenic binding initiate the antileukemia response of As2O3.

International audienceAs(2)O(3) cures acute promyelocytic leukemia (APL) by initiating PML/RARA oncoprotein degradation, through sumoylation of its PML moiety. However, how As(2)O(3) initiates PML sumoylation has remained largely unexplained. As(2)O(3) binds vicinal cysteines and increases reactive oxygen species (ROS) production. We demonstrate that upon As(2)O(3) exposure, PML undergoes ROS-initiated intermolecular disulfide formation and binds arsenic directly. Disulfide-linked PML or PML/RARA multimers form nuclear matrix-associated nuclear bodies (NBs), become sumoylated and are degraded. Hematopoietic progenitors transformed by an As(2)O(3)-binding PML/RARA mutant exhibit defective As(2)O(3) response. Conversely, nonarsenical oxidants elicit PML/RARA multimerization, NB-association, degradation, and leukemia response in vivo, but do not affect PLZF/RARA-driven APLs. Thus, PML oxidation regulates NB-biogenesis, while oxidation-enforced PML/RARA multimerization and direct arsenic-binding cooperate to enforce APL's exquisite As(2)O(3) sensitivity

Adapting cities to climate Change : a systemic modelling approach

International audienceTo answer the climate change challenge, all states have to reduce their greenhouse gas emissions, but also to adopt adaptation measures to limit the negative impacts of global warming on the population, the economy and the environment. The question arises especially for cities.Because of complex interactions between climate change, the evolution of cities and its inhabitants, studying adaptation strategies for cities requires a strong interdisciplinary approach: urban planners, architects, meteorologists, building engineers, economists, social sciences.Our four-step methodology consists firstly of defining interdisciplinary scenarios at several scales influencing the city evolution; secondly of simulating long term city evolution based on socio-economic and land-use models; thirdly of calculating impacts with physical models, and finally of calculating the indicators quantifying the adaptation strategies.Interdisciplinary systemic modelling performs well to evaluate several adaptation strategies for a very broad range of topics. Some of the results obtained for the agglomeration of Paris through our interdisciplinary research projects VURCA and MUSCADE will be discussed:A finding is that Urban planning strategies may have unexpected influence on city expansion when considered on the very long term of the climate change. Another is that the combine effect of global warming and UHI can lead in the future to larger energy consumption in summer than in winter.Indeed, air-conditioning will probably be necessary in 2100, because of expected stronger, and longer, heat waves. Limiting the UHI intensity allows for energy savings, and hence contributes to climate change mitigation. Adaptation strategies exist to limit air-conditioning use, both in time and intensity.Analysis of several vegetation strategies, at several spatial and planning scales (from agricultural practices in the city surroundings to urban trees and green-roofs) have been performed and evaluated. Architectural choices also allow to reduce the UHI. Finally, inhabitants' use and practices seem to be an efficient lever to reduce energy consumption in buildings and its impact on the urban climate

Design of Bismuth-based luminescent materials for multi-modal imaging and optical thermometry

Upconversion phosphor materials, usually consisting of crystals doped with lanthanide ions, are attracting increasing attention and several possible applications in various fields have been proposed so far: e.g. solar cells with improved efficiency, nanomaterials for bio-imaging, microtags in anti-counterfeiting inks and lasers and novel display technologies. In recent years, lanthanide (Ln3+)-doped upconverting nanoparticles (UCNPs) have proved to be photostable and basically nontoxic, thus have been presented as efficient and versatile bioimaging probes. This type of nanoparticles can be excited with near-infrared (NIR) light, while emitting higher-energy photons in a wide range of the electromagnetic spectrum, from the ultraviolet (UV), to visible (VIS) and near infrared (NIR) regions, via a multiphoton process. In particular, operating within the biological window leads to several advantages, such as drastically reduced photodamage and autofluorescence background, and remarkable tissue penetration. On the other hand, bismuth-based luminescent materials have proved to be excellent candidates for the design of bulk and nanosized phosphors, thanks to peculiar optical characteristics and appealing properties such as low cost of production and almost non-toxicity. Driven by these factors our work is mainly focused on the development of novel nanostructures, i.e. lanthanide-doped bismuth silicate-silica core-shell nanoparticles, to be employed as biological probes. A new synthetic procedure is here developed to obtain NPs composed of a crystalline Bi2SiO5 core embedded in a glassy shell of dense SiO2. Uniform, monodispersed, crystalline and non-toxic nanoparticles are obtained. The tunability of the UC emission is investigated by co-doping the system with different combinations and relative concentrations of lanthanide ions (Yb, Er, Ho, Tm). Lanthanide-doped Bi2SiO5@SiO2 NPs are thoroughly characterized, allowing to assess their potential as bioimaging and temperature sensing nanoprobes. In fact, the strongly temperature-dependent behaviour of the upconversion photoluminescence (UCPL) in lanthanide ions, allows to develop ratiometric luminescent thermal sensors, emitting in the VIS or NIR regions, with promising properties in the biological field. The Nd3+ singly-doped Bi2SiO5@SiO2 system is also investigated as thermal bio-probe and its optical properties are compared with that of two others bismuth silicate phases of the Bi2O3-SiO2 phase diagram, namely Bi4Si3O12 and Bi12SiO20. Moreover, the synthesized NPs are multifunctional, potentially being multi-modal probes for combined optical imaging and X-ray computed tomography (CT)/single-photon emission CT (SPECT)/photoacoustic tomography (PAT), thanks to the X-ray attenuating properties of the bismuth-based matrix

Poor clinical outcome despite successful basilar occlusion recanalization in the early time window: Incidence and predictors

International audienceBackground Endovascular treatment (EVT) for basilar artery occlusions (BAO) is associated with a higher rate of futile recanalization compared with anterior circulation procedures. We aimed to identify the incidence and predictors of poor clinical outcome despite successful reperfusion in current clinical practice. Methods We used data from the ETIS (Endovascular Treatment in Ischemic Stroke) registry, a prospective multicenter observational registry of stroke treated with EVT in France. Patients undergoing EVT for acute BAO from January 2014 to May 2019 successfully treated within 8 hours from onset were included. Predictors of 90-day poor outcome (modified Rankin Scale (mRS) 4-6) were researched within patients with successful (modified Thrombolysis In Cerebral Infarction (mTICI 2b-3)) and excellent (mTICI 2c-3) reperfusion. Results Among 242 patients treated within 8 hours, successful reperfusion was achieved in 195 (80.5%) and excellent reperfusion in 120 (49.5%). Poor outcome was observed in 107 (54.8%) and 60 (50%) patients, respectively. In patients with successful early reperfusion, age, higher initial National Institutes of Health Stroke Scale (NIHSS) score, lower posterior circulation Alberta Stroke Programme Early CT Score (pc-ASPECTS), and absence of prior intravenous thrombolysis were independent predictors of poor outcome. The only treatment factor with an independent predictive value was first-pass mTICI 2b-3 reperfusion (adjusted OR 0.13, 95% CI 0.05 to 0.37, p<0.001). In patients with excellent early reperfusion, independent predictors were age, initial NIHSS score, first-pass mTICI 2c-3 reperfusion, and hemorrhagic transformation on post-interventional imaging. Conclusions Early successful reperfusion with EVT occurred in 80.5% of patients, and the only treatment-related factor predictive of clinical outcome was first pass mTICI 2b-3 reperfusion. Further research is warranted to identify the optimal techniques and devices associated with first pass reperfusion in the posterior circulation

Effect of intravenous thrombolysis before endovascular therapy on outcome according to collateral status: insight from the ETIS Registry

International audienceBackground It is unknown whether collateral status modifies the effect of pretreatment intravenous thrombolysis (IVT) on the outcomes of patients with large vessel occlusions treated with endovascular therapy (EVT). We aimed to assess whether collateral status modifies the effect of IVT on the outcomes of EVT in clinical practice. Methods We used data from the ongoing prospective multicentric Endovascular Treatment in Ischemic Stroke (ETIS) Registry in France. Patients with anterior circulation proximal large vessel occlusions treated with EVT within 6 hours of symptom onset were enrolled. Patients were divided into two groups based on pretreatment with IVT. The two groups were matched based on baseline characteristics. We tested the interaction between collateral status and IVT in unadjusted and adjusted models. Results A total of 1589 patients were enrolled in the study, of whom 55% received IVT. Using a propensity score matching method, 724 no IVT patients were matched to 549 IVT patients. In propensity score weighted analysis, IVT was associated with higher odds of early neurological improvement (OR 1.74; 95% CI 1.33 to 2.26), favorable functional outcome (OR 1.66; 95% CI 1.23 to 2.24), excellent functional outcome (OR 2.04; 95% CI 1.47 to 2.83), and successful reperfusion (OR 2.18; 95% CI 1.51 to 3.16). IVT was not associated with mortality or hemorrhagic complications. There was no interaction between collateral status and IVT association with any of the outcomes. Conclusions Collateral status does not modify the effect of pretreatment IVT on the efficacy and safety outcomes of EVT