Lensing power spectrum of the Cosmic Microwave Background with deep polarization experiments

Precise reconstruction of the cosmic microwave background lensing potential can be achieved with deep polarization surveys by iteratively removing lensing-induced $B$ modes. We introduce a lensing spectrum estimator and its likelihood for such optimal iterative reconstruction. Our modelling share similarities to the state-of-the-art likelihoods for quadratic estimator-based (QE) lensing reconstruction. In particular, we generalize the $N^{(0)}$ and $N^{(1)}$ lensing biases, and design a realization-dependent spectrum debiaser, making this estimator robust to uncertainties in the data modelling. We demonstrate unbiased recovery of the cosmology using map-based reconstructions. For a CMB-S4 survey, this spectrum estimator and likelihood can double the constraints on the lensing amplitude compared to the QE on a wide range of scales, while keeping numerical cost under control and being robust to errors.Comment: 8 pages, 4 figure

Robust and efficient CMB lensing power spectrum from polarization surveys

Deep surveys of the CMB polarization have more information on the lensing signal than the quadratic estimators (QE) can capture. We showed in a recent work that a CMB lensing power spectrum built from a single optimized CMB lensing mass map, working in close analogy to state-of-the-art QE techniques, can result in an essentially optimal spectrum estimator at reasonable numerical cost. We extend this analysis here to account for real-life non-idealities including masking and realistic instrumental noise maps. As in the QE case, it is necessary to include small corrections to account for the estimator response to these anisotropies, which we demonstrate can be estimated easily from simulations. The realization-dependent debiasing of the spectrum remains robust, allowing unbiased recovery of the band powers even in cases where the statistical model used for the lensing map reconstruction is grossly wrong. This allows now robust and at the same time optimal CMB lensing constraints from CMB data, on all scales relevant for the inference of the neutrino mass, or other parameters of our cosmological model.Comment: 12 pages, 8 figures, comments are welcom

Cluster profiles from beyond-the-QE CMB lensing mass maps

Clusters of galaxies, being the largest collapsed structures in the universe, offer valuable insights into the nature of cosmic evolution. Precise calibration of the mass of clusters can be obtained by extracting their gravitational lensing signal on the Cosmic Microwave Background (CMB) fluctuations. We extend and test here the performance achieved on cluster scales by the parameter-free, maximum a posteriori (MAP) CMB lensing reconstruction method, which has been shown to be optimal in the broader context of CMB lensing mass map and power spectrum estimation. In the context of cluster lensing, the lensing signal of other large-scale structures acts as an additional source of noise. We show here that by delensing the CMB fluctuations around each and every cluster, this noise variance is reduced according to expectations. We also demonstrate that the well-known bias in the temperature quadratic estimator in this regime, sourced by the strong non-Gaussianity of the signal, is almost entirely mitigated without any scale cuts. Being statistically speaking an optimal and blind lensing mass map reconstruction, the MAP estimator is a promising tool for the calibration of the masses of clusters.Comment: 11 pages, 4 figures, prepared for PRD submissio

The structure of quasi-transitive graphs avoiding a minor with applications to the domino problem

An infinite graph is quasi-transitive if its vertex set has finitely many orbits under the action of its automorphism group. In this paper we obtain a structure theorem for locally finite quasi-transitive graphs avoiding a minor, which is reminiscent of the Robertson-Seymour Graph Minor Structure Theorem. We prove that every locally finite quasi-transitive graph $G$ avoiding a minor has a tree-decomposition whose torsos are finite or planar; moreover the tree-decomposition is canonical, i.e. invariant under the action of the automorphism group of $G$. As applications of this result, we prove the following. (i) Every locally finite quasi-transitive graph attains its Hadwiger number, that is, if such a graph contains arbitrarily large clique minors, then it contains an infinite clique minor. This extends a result of Thomassen (1992) who proved it in the 4-connected case and suggested that this assumption could be omitted. (ii) Locally finite quasi-transitive graphs avoiding a minor are accessible (in the sense of Thomassen and Woess), which extends known results on planar graphs to any proper minor-closed family. (iii) Minor-excluded finitely generated groups are accessible (in the group-theoretic sense) and finitely presented, which extends classical results on planar groups. (iv) The domino problem is decidable in a minor-excluded finitely generated group if and only if the group is virtually free, which proves the minor-excluded case of a conjecture of Ballier and Stein (2018)

Espaces transitionnels de socialisation

Traditionnellement la socialisation a été essentiellement envisagée sous le seul angle de l’éducation des enfants. Un manuel de sociologie (Mendras, 1975) s’attache ainsi surtout à « l’étude des méthodes d’élevage, d’éducation et d’enseignement ». Sans nier l’importance de cette socialisation des tout premiers âges de la vie, importance attestée par les découvertes de la psychanalyse, il convient de prendre sérieusement en compte les socialisations de la vie dite « adulte ». Avec P. Berger et..

Characterization of expressed sequence tags obtained by SSH during somatic embryogenesis in Cichorium intybus L

<p>Abstract</p> <p>Background</p> <p>Somatic embryogenesis (SE) is an asexual propagation pathway requiring a somatic-to-embryonic transition of differentiated somatic cells toward embryogenic cells capable of producing embryos in a process resembling zygotic embryogenesis. In chicory, genetic variability with respect to the formation of somatic embryos was detected between plants from a population of <it>Cichorium intybus </it>L. landrace Koospol. Though all plants from this population were self incompatible, we managed by repeated selfing to obtain a few seeds from one highly embryogenic (E) plant, K59. Among the plants grown from these seeds, one plant, C15, was found to be non-embryogenic (NE) under our SE-inducing conditions. Being closely related, we decided to exploit the difference in SE capacity between K59 and its descendant C15 to study gene expression during the early stages of SE in chicory.</p> <p>Results</p> <p>Cytological analysis indicated that in K59 leaf explants the first cell divisions leading to SE were observed at day 4 of culture. In contrast, in C15 explants no cell divisions were observed and SE development seemed arrested before cell reactivation. Using mRNAs isolated from leaf explants from both genotypes after 4 days of culture under SE-inducing conditions, an E and a NE cDNA-library were generated by SSH. A total of 3,348 ESTs from both libraries turned out to represent a maximum of 2,077 genes. <it>In silico </it>subtraction analysis sorted only 33 genes as differentially expressed in the E or NE genotype, indicating that SSH had resulted in an effective normalisation. Real-time RT-PCR was used to verify the expression levels of 48 genes represented by ESTs from either library. The results showed preferential expression of genes related to protein synthesis and cell division in the E genotype, and related to defence in the NE genotype.</p> <p>Conclusion</p> <p>In accordance with the cytological observations, mRNA levels in explants from K59 and C15 collected at day 4 of SE culture reflected differential gene expression that presumably are related to processes accompanying early stages of direct SE. The E and NE library obtained thus represent important tools for subsequent detailed analysis of molecular mechanisms underlying this process in chicory, and its genetic control.</p

20 % Reduction of CO2-Emissions with Power-to-Gas in WWTP

The engineering company Witteveen+Bos and the Water Board Aa en Maas explored the potential of a new concept combining Power-to-Gas (PtG) and sludge digestion in Wastewater Treatment Plant (WWTP) Cuijck. This project aims to tackle two topical issues at once, which are respectively the need for increase of energy storage for renewable energy production and the need for reduction of greenhouse gas emissions. The main conclusion of this study shows that Powerto- Gas systems can reduce around 20 % of the carbon dioxide (CO2) emissions and provide long term storage of 126.5 MWh/year (140 579 Nm3 Synthetic Natural Gas/year) at the WWTP of Land van Cuijk

Transgenerational plasticity of dispersal‐related traits in a ciliate: genotype‐dependency and fitness consequences

Phenotypic plasticity, the ability of one genotype to produce different phenotypes in different environments, plays a central role in species' response to environmental changes. Transgenerational plasticity (TGP) allows the transmission of this environmentally-induced phenotypic variation across generations, and can influence adaptation. To date, the genetic control of TGP, its long-term stability, and its potential costs remain largely unknown, mostly because empirical demonstrations of TGP across many generations in several genetic backgrounds are scarce. Here, we examined how genotype determines the TGP of phenotypic traits related to dispersal, a fundamental process in ecology and evolution. We used an experimental approach in Tetrahymena thermophila, a ciliate model-species, to determine if and how phenotypic changes expressed following a dispersal treatment are inherited over multiple generations. Our results show that morphological and movement traits associated with dispersal are plastic, and that these modifications are inherited over at least 35 generations. The fitness costs and benefits associated with these plastic changes are also transmitted to further generations. We highlight that the genotype modulates the expression and reversibility of transgenerational plasticity of dispersal-related traits and its fitness outcomes. Our study thus suggests that genotype-dependent TGP could play an important role in eco-evolutionary dynamics as dispersal determines gene flow and the long-term persistence of natural populations

Identification of novel genes potentially involved in somatic embryogenesis in chicory (Cichorium intybus L.)

<p>Abstract</p> <p>Background</p> <p>In our laboratory we use cultured chicory (<it>Cichorium intybus</it>) explants as a model to investigate cell reactivation and somatic embryogenesis and have produced 2 chicory genotypes (K59, C15) sharing a similar genetic background. K59 is a responsive genotype (embryogenic) capable of undergoing complete cell reactivation <it>i.e</it>. cell de- and re-differentiation leading to somatic embryogenesis (SE), whereas C15 is a non-responsive genotype (non-embryogenic) and is unable to undergo SE. Previous studies <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> showed that the use of the β-D-glucosyl Yariv reagent (β-GlcY) that specifically binds arabinogalactan-proteins (AGPs) blocked somatic embryo production in chicory root explants. This observation indicates that β-GlcY is a useful tool for investigating somatic embryogenesis (SE) in chicory. In addition, a putative AGP (DT212818) encoding gene was previously found to be significantly up-regulated in the embryogenic K59 chicory genotype as compared to the non-embryogenic C15 genotype suggesting that this AGP could be involved in chicory re-differentiation <abbrgrp><abbr bid="B2">2</abbr></abbrgrp>. In order to improve our understanding of the molecular and cellular regulation underlying SE in chicory, we undertook a detailed cytological study of cell reactivation events in K59 and C15 genotypes, and used microarray profiling to compare gene expression in these 2 genotypes. In addition we also used β-GlcY to block SE in order to identify genes potentially involved in this process.</p> <p>Results</p> <p>Microscopy confirmed that only the K59, but not the C15 genotype underwent complete cell reactivation leading to SE formation. β-GlcY-treatment of explants blocked <it>in vitro </it>SE induction, but not cell reactivation, and induced cell wall modifications. Microarray analyses revealed that 78 genes were differentially expressed between induced K59 and C15 genotypes. The expression profiles of 19 genes were modified by β-GlcY-treatment. Eight genes were both differentially expressed between K59 and C15 genotypes during SE induction and transcriptionally affected by β-GlcY-treatment: <it>AGP </it>(DT212818), <it>26 S proteasome AAA ATPase subunit 6 </it>(<it>RPT6</it>), <it>remorin </it>(<it>REM</it>), <it>metallothionein-1 </it>(<it>MT1</it>), two non-specific lipid transfer proteins genes (<it>SDI-9 and DEA1</it>), <it>3-hydroxy-3-methylglutaryl-CoA reductase </it>(<it>HMG-CoA reductase</it>), and <it>snakin 2 </it>(<it>SN2</it>). These results suggest that the 8 genes, including the previously-identified <it>AGP </it>gene (DT212818), could be involved in cell fate determination events leading to SE commitment in chicory.</p> <p>Conclusion</p> <p>The use of two different chicory genotypes differing in their responsiveness to SE induction, together with β-GlcY-treatment represented an efficient tool to discriminate cell reactivation from the SE morphogenetic pathway. Such an approach, together with microarray analyses, permitted us to identify several putative key genes related to the SE morphogenetic pathway in chicory.</p

Le partenariat au service de l’évaluation des projets d’éducation relative à l’environnement

Évaluer des projets d’éducation relative à l’environnement (ErE) avec tous les acteurs concernés et impliqués dans le projet, est-ce seulement une utopie de chercheurs ? À travers l’analyse de deux expériences, cet article cherche à démontrer la cohérence d’un partenariat dans l’évaluation de projets avec les objectifs poursuivis par l’ErE. Il précise le terme « partenariat », analyse les avantages vécus et précise les problèmes rencontrés lors d’évaluations menées à plusieurs selon les types de projets d’ErE et selon les moments de l’action. Un ensemble de questions est proposé, questions que tout praticien pourra se poser avant de se lancer dans une telle démarche aussi riche que complexe.Is it a researchers’ utopia to evaluate environmental education (EE) projects with all concerned and involved actors ? This paper, through the analysis of two experiences, aims to demonstrate the coherence of partnership in the evaluation of projects, with the pursuit of EE objectives. This paper also defines the term “partnership”, analyses the advantages experienced and details the problems encountered in evaluations conducted in a collaborative process, according to the types of EE projects and the moments of action. A series of questions is proposed which questions all practitioners may ask themselves before getting involved in such a rich and complex process