A Linearization Technique for Multivariate Polynomials Using Convex Polyhedra Based on Handelman-Krivine's Theorem

National audienceWe present a new linearization method to over-approximate non-linear multivariate polynomials with convex polyhedra.It is based on Handelman-Krivine's theorem and consists in using products of constraints of a polyhedron to over-approximate a polynomial on this polyhedron. We implemented it together with two other linearization methods that we will not detail in this paper, but that we shall use as comparison. Our implementation in Ocaml generates certificates that can be verified by a trusted checker, certified in Coq, that guarantees the correctness of our linear approximation

Un rôle pour les protéines de la famille Whirly dans le maintien de la stabilité du génome des organelles chez Arabidopsis thaliana

Le maintien de la stabilité du génome est essentiel pour la propagation de l’information génétique et pour la croissance et la survie des cellules. Tous les organismes possèdent des systèmes de prévention des dommages et des réarrangements de l’ADN et nos connaissances sur ces processus découlent principalement de l’étude des génomes bactériens et nucléaires. Comparativement peu de choses sont connues sur les systèmes de protection des génomes d’organelles. Cette étude révèle l’importance des protéines liant l’ADN simple-brin de la famille Whirly dans le maintien de la stabilité du génome des organelles de plantes. Nous rapportons que les Whirlies sont requis pour la stabilité du génome plastidique chez Arabidopsis thaliana et Zea mays. L’absence des Whirlies plastidiques favorise une accumulation de molécules rearrangées produites par recombinaison non-homologue médiée par des régions de microhomologie. Ce mécanisme est similaire au “microhomology-mediated break-induced replication” (MMBIR) retrouvé chez les bactéries, la levure et l’humain. Nous montrons également que les organelles de plantes peuvent réparer les bris double-brin en utilisant une voie semblable au MMBIR. La délétion de différents membres de la famille Whirly entraîne une accumulation importante de réarrangements dans le génome des organelles suite à l’induction de bris double-brin. Ces résultats indiquent que les Whirlies sont aussi importants pour la réparation fidèle des génomes d’organelles. En se basant sur des données biologiques et structurales, nous proposons un modèle où les Whirlies modulent la disponibilité de l’ADN simple-brin, régulant ainsi le choix des voies de réparation et permettant le maintien de la stabilité du génome des organelles. Les divers aspects de ce modèle seront testés au cours d’expériences futures ce qui mènera à une meilleure compréhension du maintien de la stabilité du génome des organelles.Maintenance of genome stability is essential for the accurate propagation of genetic information and for cell growth and survival. Organisms have therefore developed efficient strategies to prevent DNA lesions and rearrangements. Much of the information concerning these strategies has been obtained through the study of bacterial and nuclear genomes. Comparatively little is known about how organelle genomes maintain a stable structure. This study implicates the single-stranded nucleic acid-binding proteins of the Whirly family in the maintenance of plant organelle genome stability. Here we report that the plastid-localized single-stranded DNA binding proteins of the Whirly family are required for plastid genome stability in Arabidopsis thaliana and Zea mays. Absence of plastidial Whirlies favors the accumulation of rearranged molecules that arise through a non-homologous recombination mechanism mediated by regions of microhomology. This mechanism is similar to the microhomology-mediated break-induced replication (MMBIR) described in bacteria, yeast and humans. Additionally we show that plant organelles can repair double-strand breaks using a MMBIR-like pathway. Plants lacking Whirly proteins accumulate elevated levels of microhomology-mediated DNA rearrangements upon double-strand break induction, indicating that Whirlies also contribute to the accurate repair of plant organelle genomes. Using biological and structural data, we propose a working model in which Whirlies modulate the access of repair proteins and complementary DNA to single-stranded regions, thereby regulating the choice of repair pathways and maintaining plant organelle genome stability. The various aspects of this model will be tested in future experiments which should allow a better understanding of the mechanisms underlying genome stability in plant organelles

Polyhedral Approximation of Multivariate Polynomials using Handelman's Theorem

International audienceConvex polyhedra are commonly used in the static analysis of programs to represent over-approximations of sets of reachable states of numerical program variables. When the analyzed programs contain nonlinear instructions, they do not directly map to standard polyhedral operations: some kind of linearization is needed. Convex polyhe-dra are also used in satisfiability modulo theory solvers which combine a propositional satisfiability solver with a fast emptiness check for polyhedra. Existing decision procedures become expensive when nonlinear constraints are involved: a fast procedure to ensure emptiness of systems of nonlinear constraints is needed. We present a new linearization algorithm based on Handelman's representation of positive polynomials. Given a polyhedron and a polynomial (in)equality, we compute a polyhedron enclosing their intersection as the solution of a parametric linear programming problem. To get a scalable algorithm, we provide several heuristics that guide the construction of the Handelman's representation. To ensure the correctness of our polyhedral approximation , our Ocaml implementation generates certificates verified by a checker certified in Coq

In-building waste water heat recovery: urban-scale methods for the characterisation of water streams and the assessment of energy savings and costs

Residential domestic hot water (DHW) energy consumption represented 16% of the EU household heating demand in 2013. With the improvement of the building envelop, DHW contribution to energy consumption is expected to increase signi cantly, with values between 20% to 32% in single family buildings, and between 35% to almost 50% in multifamily buildings. This energy, currently lost to the environment, can be recovered by waste water heat recovery (WWHR) systems inside buildings (in-building solution). However, the characterisation of residential grey water streams at urban scale has barely been addressed. Also, the impact of such solutions on the total heating consumption and the related costs has not been assessed in detail for di erent types of residential buildings or for urban systems. The characterisation and geoallocation method of grey water streams as to mass ow and tem- perature level is therefore addressed. A method to quantify the energy saving potential and costs at urban scale of in-building WWHR systems in residential buildings is also proposed. These methods are applied in two case-studies, rst as retro tting solution in a city in Luxembourg and, second, as optimisation measure for high e ciency residential buildings. Grey water heat recovery would reduce the residential fuel consumption of the city by 6.3%. An integrated approach combining grey water heat recovery for hot water preheating and a heat pump yields up to 28% and 41% electricity savings for passive single family houses and multifamily buildings, respectively. With the detailed characterisation of various grey water streams in function of inhabitant number and end-use occurrence, the quanti cation of the energy savings and costs through heat recovery is improved. The outcomes of urban energy and cost assessments concerning grey water heat recovery are more speci c, as the results at building level are aggregated to the considered geographical scope. The proposed method therefore complements current urban energy and cost assessments with the detailed integration of in-building grey water heat recovery systems

Attichy – L'Avenue

Identifiant de l'opération archéologique : 9019 Date de l'opération : 2006 (MH) La fouille, dans cette future carrière, fait suite aux résultats du diagnostic mené sous la direction de M. Friboulet (Inrap) en 2005. La parcelle se situe dans la vallée de l’Aisne, sur sa rive droite. Le cours d’eau coule à 625 m au sud du gisement. Le site est placé sur la première terrasse de la rivière. Un paléochenal se développe à moins de 100 m du bord du décapage. Il suffit de retirer 0,30 m à 0,50 m d’ép..

Heat demand estimation for different building types at regional scale considering building parameters and urban topography

This study aims towards an improved estimation of annual heat demand of the building stock for an entire region. This requires the holistic representation of aspects influencing the heat demand of buildings, namely their geometry, fabric, users and surrounding environment. A large data base for the building stock of the Swiss canton of Geneva was systematically assessed to identify parameters suited for representation of these aspects. Due to the expectable differences in heat demand, the building stock was categorized into 8 building types. For each type a multiple linear regression model was developed to predict the heat demand. An aspect which has so far been neglected by regression models of buildings’ heat demand is the influence of microclimate. Since this aspect is considerably influenced by the surrounding topography, parameters suited for the representation of the urban topography were defined and included in the regression. The regression analysis revealed that all models were able to explain high shares of the variance (R²: 71.2% to 88.9%). The mean average errors for hotel, health-care, educational and office buildings were ranging between 30.2% and 39.8% while the error for residential buildings was 17.8%. The suitability and of the selected parameters for heat demand prediction was analyzed in detail for the residential building model and revealed that almost all chosen parameters were highly suited

Characterisation of domestic hot water end-uses for integrated urban thermal energy assessment and optimisation

Former integrated urban energy assessments and optimisation have modelled domestic hot water (DHW) demand as a single stream, as space heating, currently, is the main energy demand in buildings and a detailed DHW modelling was therefore not required. However, the characterisation of energy saving measures (e.g. grey water heat recovery) and the selection of optimal heating utility in buildings with low temperature space heating would benefit from a differentiation of the various DHW end-uses at urban scale (building blocks, streets, districts, city). To this end, a new method characterising the main DHW appliances in households, hotels and nursing homes at urban level, is proposed. A review of European publications characterising water uses is conducted and utility load and energy consumption equations are developed. A specific model for district heating heat exchangers without thermal storage for integrated urban energy optimisation is proposed. The DHW-related energy consumption results are confirmed by literature values in a real urban case-study. Showering represents more than 80% of the DHW energy demand, and more than 97% of the total DHW heat use is required up to 40°C. The proposed method contributes to urban energy assessments and optimisation by improving the level of detail of the outcomes and by strengthening their integrated approach

Smart framework for real-time monitoring and control of subsurface processes in managed aquifer recharge applications: project outlook

International audienc

Neutrophil Extracellular Traps Are Found in Bronchoalveolar Lavage Fluids of Horses With Severe Asthma and Correlate With Asthma Severity

peer reviewedAsthma encompasses a spectrum of heterogenous immune-mediated respiratory disorders sharing a similar clinical pattern characterized by cough, wheeze and exercise intolerance. In horses, equine asthma can be subdivided into severe or moderate asthma according to clinical symptoms and the extent of airway neutrophilic inflammation. While severe asthmatic horses are characterized by an elevated neutrophilic inflammation of the lower airways, cough, dyspnea at rest and high mucus secretion, horses with moderate asthma show a milder neutrophilic inflammation, exhibit intolerance to exercise but no labored breathing at rest. Yet, the physiopathology of different phenotypes of equine asthma remains poorly understood and there is a need to elucidate the underlying mechanisms tailoring those phenotypes in order to improve clinical management and elaborate novel therapeutic strategies. In this study, we sought to quantify the presence of neutrophil extracellular traps (NETs) in bronchoalveolar lavage fluids (BALF) of moderate or severe asthmatic horses and healthy controls, and assessed whether NETs correlated with disease severity. To this end, we evaluated the amounts of NETs by measuring cell- free DNA and MPO-DNA complexes in BALF supernatants or by quantifying NETs release by BALF cells by confocal microscopy. We were able to unequivocally identify elevated NETs levels in BALF of severe asthmatic horses as compared to healthy controls or moderate asthmatic horses. Moreover, we provided evidence that BALF NETs release was a specific feature seen in severe equine asthma, as opposed to moderate asthma, and correlated with disease severity. Finally, we showed that NETs could act as a predictive factor for severe equine asthma. Our study thus uniquely identifies NETs in BALF of severe asthmatic horses using three distinct methods and supports the idea that moderate and severe equine asthma do not rely on strictly similar pathophysiological mechanisms. Our data also suggest that NETs represent a relevant biomarker, a putative driver and a potential therapeutic target in severe asthma diseas