Sub-cubic Change of Ordering for Gröner Basis: A Probabilistic Approach

International audienceThe usual algorithm to solve polynomial systems using Gröbner bases consists of two steps: first computing the DRL Gröbner basis using the F5 algorithm then computing the LEX Gröbner basis using a change of ordering algorithm. When the Bézout bound is reached, the bottleneck of the total solving process is the change of ordering step. For 20 years, thanks to the FGLM algorithm the complexity of change of ordering is known to be cubic in the number of solutions of the system to solve. We show that, in the generic case or up to a generic linear change of variables, the multiplicative structure of the quotient ring can be computed with no arithmetic operation. Moreover, given this multiplicative structure we propose a change of ordering algorithm for Shape Position ideals whose complexity is polynomial in the number of solutions with exponent ω where 2 ≤ ω < 2.3727 is the exponent in the complexity of multiplying two dense matrices. As a consequence, we propose a new Las Vegas algorithm for solving polynomial systems with a finite number of solutions by using Gröbner basis for which the change of ordering step has a sub-cubic (i.e. with exponent ω) complexity and whose total complexity is dominated by the complexity of the F5 algorithm. In practice we obtain significant speedups for various polynomial systems by a factor up to 1500 for specific cases and we are now able to tackle some instances that were intractable

PARASO, a circum-Antarctic fully coupled ice-sheet–ocean–sea-ice–atmosphere–land model involving f.ETISh1.7, NEMO3.6, LIM3.6, COSMO5.0 and CLM4.5

We introduce PARASO, a novel five-component fully coupled regional climate model over an Antarctic circumpolar domain covering the full Southern Ocean. The state-of-the-art models used are the fast Elementary Thermomechanical Ice Sheet model (f.ETISh) v1.7 (ice sheet), the Nucleus for European Modelling of the Ocean (NEMO) v3.6 (ocean), the Louvain-la-Neuve sea-ice model (LIM) v3.6 (sea ice), the COnsortium for Small-scale MOdeling (COSMO) model v5.0 (atmosphere) and its CLimate Mode (CLM) v4.5 (land), which are here run at a horizontal resolution close to 1/4°. One key feature of this tool resides in a novel two-way coupling interface for representing ocean–ice-sheet interactions, through explicitly resolved ice-shelf cavities. The impact of atmospheric processes on the Antarctic ice sheet is also conveyed through computed COSMO-CLM–f.ETISh surface mass exchange. In this technical paper, we briefly introduce each model's configuration and document the developments that were carried out in order to establish PARASO. The new offline-based NEMO–f.ETISh coupling interface is thoroughly described. Our developments also include a new surface tiling approach to combine open-ocean and sea-ice-covered cells within COSMO, which was required to make this model relevant in the context of coupled simulations in polar regions. We present results from a 2000–2001 coupled 2-year experiment. PARASO is numerically stable and fully operational. The 2-year simulation conducted without fine tuning of the model reproduced the main expected features, although remaining systematic biases provide perspectives for further adjustment and development.This research has been supported by the Fonds De La Recherche Scientifique – FNRS (grant no. O0100718F).Peer ReviewedArticle signat per 23 autors/es: Charles Pelletier (1), Thierry Fichefet (1), Hugues Goosse (1), Konstanze Haubner (2), Samuel Helsen (3), Pierre-Vincent Huot (1), Christoph Kittel (4), François Klein (1), Sébastien Le clec'h (5), Nicole P. M. van Lipzig (3), Sylvain Marchi (3), François Massonnet (1), Pierre Mathiot (6,7), Ehsan Moravveji (3,8), Eduardo Moreno-Chamarro (9), Pablo Ortega (9), Frank Pattyn (2), Niels Souverijns (3,10), Guillian Van Achter (1), Sam Vanden Broucke (3), Alexander Vanhulle (5), Deborah Verfaillie (1), and Lars Zipf (2) // (1) Earth and Life Institute (ELI), UCLouvain, Louvain-la-Neuve, Belgium / (2) Laboratoire de Glaciologie, Université Libre de Bruxelles, Brussels, Belgium / (3) Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium / (4) Laboratory of Climatology, Department of Geography, SPHERES, University of Liège, Liège, Belgium / (5) Earth System Science and Departement Geografie, Vrije Universiteit Brussel, Brussels, Belgium, (6) Met Office, Exeter, United Kingdom / (7) Université Grenoble Alpes/CNRS/IRD/G-INP, IGE, Grenoble, France / (8) ICTS, KU Leuven, Leuven, Belgium / (9) Barcelona Supercomputing Center (BSC), Barcelona, Spain / (10) Environmental Modelling Unit, Flemish Institute for Technological Research (VITO), Mol, BelgiumPostprint (published version

Treatment With Treprostinil and Metformin Normalizes Hyperglycemia and Improves Cardiac Function in Pulmonary Hypertension Associated With Heart Failure With Preserved Ejection Fraction

Objective: Pulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF. Approach and Results: Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle. Conclusions: Our data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease

A Politico-Communal Reading of the Rose

Lettura del Fiore in rapporto alle fonti retoriche e politiche di ambiente comunal

Modalités et contextes de mise en place des ophiolites (arguments tirés de l'analyse des mélanges ophiolitiques)

BREST-BU Droit-Sciences-Sports (290192103) / SudocRENNES-Géosciences (352382209) / SudocSudocFranceF

A new method for analysing dowloaded data for strategic decision

International audienc

Les méthodes d'analyse des données face à l'information stratégique et l'innovation

International audienc

Céramique culinaire et céramique de poêle du haut Moyen Âge en Lorraine du sud : l’apport des fouilles du Saint-Mont (88)

En Lorraine, la céramique du haut Moyen Âge est mal connue ; aucun site de production n’est répertorié et les fouilles d’habitats, lorsqu’elles existent, sont encore rarement publiées. L’ouvrage de référence reste donc en tout état de cause le remarquable, mais déjà ancien travail d’Edouard Salin. Pour la Lorraine du sud, l’étude du matériel céramique exhumé lors des fouilles programmées du Saint-Mont (88) contribue donc à combler cette lacune. Deux lots ont été individualisés : d’une part, les céramiques culinaires de la fine sigillée aux céramiques grise à pâte grossière ornée le plus souvent de molettes, en passant par des céramiques carénées noires lustrées caractéristiques de la première époque franque ; d’autre part, une catégorie originale de pots, jusqu’alors absente de la région qu’il convient de regarder comme des pots de poêle dont les seuls exemplaires connus ont été répertoriées en Alsace. Ce mobilier témoigne à sa manière du confort dans lequel vivaient les religieuses issues pour la plupart de la noblesse austrasienne.Kraemer Charles, Huot-Marchand Guillaume, Voirin Martine. Céramique culinaire et céramique de poêle du haut Moyen Âge en Lorraine du sud : l’apport des fouilles du Saint-Mont (88). In: Les arts du feu. Actes du 127e Congrès national des sociétés historiques et scientifiques, « Le travail et les hommes », Nancy, 2002. Paris : Editions du CTHS, 2009. pp. 141-162. (Actes des congrès nationaux des sociétés historiques et scientifiques, 127-10