DISCORL: Continual reinforcement learning via policy distillation: A preprint

International audienceIn multi-task reinforcement learning there are two main challenges: at training time, the ability to learn different policies with a single model; at test time, inferring which of those policies applying without an external signal. In the case of continual reinforcement learning a third challenge arises: learning tasks sequentially without forgetting the previous ones. In this paper, we tackle these challenges by proposing DisCoRL, an approach combining state representation learning and policy distillation. We experiment on a sequence of three simulated 2D navigation tasks with a 3 wheel omni-directional robot. Moreover, we tested our approach's robustness by transferring the final policy into a real life setting. The policy can solve all tasks and automatically infer which one to run

Plan for promoting the demonstrated systems and technologies for further development – D6.4

This report is the output of the task 6.4 to approach a Plan for promoting the  demonstrated systems and technologies for further deployment. The goal of this task was divided into four specific objectives: 1. To assess the role of the demonstrated new or improved machinery for the sustainable and reliable supply of forest biomass to the facilities, with special focus on cost reduction and/or additional biomass supply that can be achieved by the demonstrated innovative technology; 2. To make proposals to promote the innovation and subsequent technology transfer and to present suggestions on how the inventions that have been developed in this project can overcome the obstacles encountered and reach commercialization; 3. To develop scenarios for the potential markets of lignocellulosic forestry residues for biorefineries and energy use; 4. To perform a risk assessment to estimate the side‐effects of not putting interesting inventions into practice. In the first part, there is a summary of the assessment of the machinery demonstrated in the framework of the INFRES project. Some of the main advantages of the innovations are the cost reduction in comparison with conventional systems, in addition to improved productivity and increased supply. Besides this, a couple of innovations showed fuel savings compared to previous supply chains. Moreover, other improvements have been observed, but without a quantitative assessment. Finally, as a conclusion, certain innovations are successful only when they are used in the conditions they were designed for. In the second part, a plan for overcoming the previously identified barriers was elaborated, and the plan was then submitted for assessment by several experts. The application of the most important measures to overcome the barriers that manufacturers face when developing an innovation is mainly in the hands of the manufacturers themselves, and partly in the hands of policy makers who may contribute through the development of appropriate financing instruments or compensations for high‐risk investments in SME’s. In the case of measures proposed to overcome the barriers that manufacturers face during the implementation or use phase, the application of the measures is in the hands of a balanced mix of the main stakeholders, including forest companies and manufacturers. It means that both have to work, sometimes together, to overcome the detected barriers. In the third part, any of the future scenarios anticipates an increase in woody biomass demand. The growth of the biorefinery sector will change the landscape of the forest biomass requirements by 2030. Indeed, feedstocks such as forest residues and stumps can be easily used by this sector. Besides this, the increase and improvement of the machinery used in the forest biomass supply chains, together with the optimization of the whole chains, take some time. As a consequence, it is a challenge for Europe to reach high enough competitiveness and innovation levels so as to cover the demand needs in the best way, with its own resources, seeking a positive impact on all EU regions and on European machinery manufacturers. Finally, the fourth part concludes that if technological and logistical innovations are not implemented in forest biomass supply chains, then energy and environmental targets in the EU will not be reached. Sustainability and cost efficiency gains in the biomass supply chains will not be achieved either. The introduction of innovative solutions as those presented by INFRES will be made possible by implementing the measures that were identified in the third part for overcoming the barriers in the development, implementation and use phases of the innovations.201

Dense active matter model of motion patterns in confluent cell monolayers

Epithelial cell monolayers show remarkable displacement and velocity correlations over distances of ten or more cell sizes that are reminiscent of supercooled liquids and active nematics. We show that many observed features can be described within the framework of dense active matter, and argue that persistent uncoordinated cell motility coupled to the collective elastic modes of the cell sheet is sufficient to produce swirl-like correlations. We obtain this result using both continuum active linear elasticity and a normal modes formalism, and validate analytical predictions with numerical simulations of two agent-based cell models, soft elastic particles and the self-propelled Voronoi model together with in-vitro experiments of confluent corneal epithelial cell sheets. Simulations and normal mode analysis perfectly match when tissue-level reorganisation occurs on times longer than the persistence time of cell motility. Our analytical model quantitatively matches measured velocity correlation functions over more than a decade with a single fitting parameter.Comment: updated version accepted for publication in Nat. Com

DISCORL: Continual reinforcement learning via policy distillation: A preprint

International audienceIn multi-task reinforcement learning there are two main challenges: at training time, the ability to learn different policies with a single model; at test time, inferring which of those policies applying without an external signal. In the case of continual reinforcement learning a third challenge arises: learning tasks sequentially without forgetting the previous ones. In this paper, we tackle these challenges by proposing DisCoRL, an approach combining state representation learning and policy distillation. We experiment on a sequence of three simulated 2D navigation tasks with a 3 wheel omni-directional robot. Moreover, we tested our approach's robustness by transferring the final policy into a real life setting. The policy can solve all tasks and automatically infer which one to run

Pigs are not susceptible to SARS‐CoV‐2 infection but are a model for viral immunogenicity studies

Conventional piglets were inoculated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) through different routes, including intranasal, intratracheal, intramuscular and intravenous ones. Although piglets were not susceptible to SARS‐CoV‐2 and lacked lesions or viral RNA in tissues/swabs, seroconversion was observed in pigs inoculated parenterally (intramuscularly or intravenously).The CBIG Consortium (constituted by IRTA‐CReSA, BSC, & IrsiCaixa) is supported by Grifols pharmaceutical. The authors also acknowledge the crowdfunding initiative of https://www.yomecorono.com.Peer ReviewedPostprint (published version

Pigs are not susceptible to SARS‐CoV‐2 infection but are a model for viral immunogenicity studies

Conventional piglets were inoculated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through different routes, including intranasal, intratracheal, intramuscular and intravenous ones. Although piglets were not susceptible to SARS-CoV-2 and lacked lesions or viral RNA in tissues/swabs, seroconversion was observed in pigs inoculated parenterally (intramuscularly or intravenously).info:eu-repo/semantics/publishedVersio

Parasitism by the Endoparasitoid, Cotesia flavipes Induces Cellular Immunosuppression and Enhances Susceptibility of the Sugar Cane Borer, Diatraea saccharalis to Bacillus thuringiensis

Cotesia flavipes Cameron (Hymenoptera: Braconidae), is a gregarious larval endoparasitoid of the sugarcane borer, Diatraea saccharalis Fabricius (Lepidoptera: Crambidae). The aim of this research was to analyze cellular immunosuppression of D. saccharalis parasitized by C. flavipes in terms of encapsulation, melanization, and hemocyte nodule formation. The encapsulation assay was done 1 and 6 days after parasitoid oviposition. In addition, the susceptibility of parasitized and nonparasitzed larvae to Bacillus thuringiensis HD 73 strain was assessed. 3, 12, and 24 h after bead injection; the percentages of encapsulation were significantly higher in unparasitized larvae compared to larvae parasitized 1 and 6 days after oviposition. Interestingly, there was a significant reduction in numbers of beads encapsulated at 1 day after oviposition compared to 6 days, and unparasitized larvae. The percentage of melanized beads decreased significantly in parasitized larvae compared to control. There was a reduction in the number of nodules in parasitized larvae compared to unparasitized controls. Larvae that were injected with polyndavirus 24 h before beads were injected showed significantly reduced encapsulation responses relative to control larvae. The D. saccharalis parasitized by C. flavipes exhibited higher susceptibility to B. thuringiensis. These results suggest that parasitization induced host immunosuppression, and the immunosuppression factors could impair the defense capacity against microbial pathogens - causing an increase in pathogen susceptibility

Protection against reinfection with D614- or G614-SARS-CoV-2 isolates in golden Syrian hamster

Reinfections with SARS-CoV-2 have already been documented in humans, although its real incidence is currently unknown. Besides having a great impact on public health, this phenomenon raises the question of immunity generated by a single infection is sufficient to provide sterilizing/protective immunity to a subsequent SARS-CoV-2 re-exposure. The Golden Syrian hamster is a manageable animal model to explore immunological mechanisms able to counteract COVID-19, as it recapitulates pathological aspects of mild to moderately affected patients. Here, we report that SARS-CoV-2-inoculated hamsters resolve infection in the upper and lower respiratory tracts within seven days upon inoculation with the Cat01 (G614) SARS-CoV-2 isolate. Three weeks after the primary challenge, and despite high titres of neutralizing antibodies, half of the animals were susceptible to reinfection by both identical (Cat01, G614) and variant (WA/1, D614) SARS-CoV-2 isolates. However, upon re-inoculation, only nasal tissues were transiently infected with much lower viral replication than those observed after the first inoculation. These data indicate that a primary SARS-CoV-2 infection is not sufficient to elicit a sterilizing immunity in hamster models but protects against lung disease.info:eu-repo/semantics/publishedVersio

The magnetic field toward the young planetary nebula K~3-35

K 3-35 is a planetary nebula (PN) where H2O maser emission has been detected, suggesting that it departed from the proto-PNe phase only some decades ago. Interferometric VLA observations of the OH 18 cm transitions in K~3-35 are presented.OH maser emission is detected in all four ground state lines (1612, 1665, 1667, and 1720 MHz). All the masers appear blueshifted with respect to the systemic velocity of the nebula and they have different spatial and kinematic distributions.The OH 1665 and 1720 MHz masers appear spatially coincident with the core of the nebula, while the OH 1612 and 1667 MHz ones exhibit a more extended distribution. We suggest that the 1665 and 1720 masers arise from a region close to the central star, possibly in a torus, while the 1612 and 1667 lines originate mainly from the extended northern lobe of the outflow. It is worth noting that the location and velocity of the OH 1720 MHz maser emission are very similar to those of the H2O masers (coinciding within 0.1" and ~2 km/s, respectively). We suggest that the pumping mechanism in the H2O masers could be produced by the same shock that is exciting the OH 1720 MHz transition. A high degree of circular polarization (>50%) was found to be present in some features of the 1612, 1665, and 1720 MHz emission.For the 1665 MHz transition at ~ +18 km/s the emission with left and right circular polarizations (LCP and RCP) coincide spatially within a region of ~0.03" in diameter.Assuming that these RCP and LCP 1665 features come from a Zeeman pair, we estimate a magnetic field of ~0.9 mG within 150 AU from the 1.3 cm continuum peak. This value is in agreement with a solar-type magnetic field associated with evolved stars.Comment: 6 pages, 2 tables, 4 figures, ApJ accepte