Local and global properties of solutions of quasilinear Hamilton-Jacobi equations

We study some properties of the solutions of (E) \;-\Gd_p u+|\nabla u|^q=0 in a domain \Gw \sbs \BBR^N, mostly when $p\geq q>p-1$. We give a universal priori estimate of the gradient of the solutions with respect to the distance to the boundary. We give a full classification of the isolated singularities of the positive solutions of (E), a partial classification of isolated singularities of the negative solutions. We prove a general removability result in expressed in terms of some Bessel capacity of the removable set. We extend our estimates to equations on complete non compact manifolds satisfying a lower bound estimate on the Ricci curvature, and derive some Liouville type theorems.Comment: to appear J. Funct. Ana

Quasilinear Lane-Emden equations with absorption and measure data

We study the existence of solutions to the equation -\Gd_pu+g(x,u)=\mu when $g(x,.)$ is a nondecreasing function and \gm a measure. We characterize the good measures, i.e. the ones for which the problem as a renormalized solution. We study particularly the cases where g(x,u)=\abs x^{\beta}\abs u^{q-1}u and g(x,u)=\abs x^{\tau}\rm{sgn}(u)(e^{\tau\abs u^\lambda}-1). The results state that a measure is good if it is absolutely continuous with respect to an appropriate Lorentz-Bessel capacities.Comment: 28 page

Gestion de l'instabilité des prix agricoles en Afrique. Quatre conditions d'efficacité des politiques

La flambée des prix des produits agricoles de 2007/2008, suivie d'une baisse en 2009/2010, puis d'une nouvelle hausse en 2010/2011, a placé la gestion de l'instabilité des prix agricoles au coeur des débats politiques. De nombreux pays en développement ont mis en oeuvre des politiques pour limiter l'instabilité des prix agricoles et ses effets préjudiciables, sans toujours atteindre les résultats escomptés. L'analyse d'expériences récentes en Afrique montre que, pour être efficace, chaque mesure politique suppose de satisfaire quatre conditions : elle doit s'appuyer sur des connaissances solides ; elle doit être prévisible ; son financement doit être assuré ; et sa mise en oeuvre contrôlée

Balneola alkaliphila sp. nov., a marine bacterium isolated from the Mediterranean Sea

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2008/publication-5292.pdfInternational audienceA novel aerobic, Gram-negative bacterium, designated strain CM41_14b(T), was isolated from surface waters in the coastal north-western Mediterranean Sea. Cells were non-motile, straight rods, 2.6 microm long and 0.7 microm wide and formed pale-orange colonies on marine agar medium. The G+C content of the genomic DNA was 39 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence placed the strain within the genus Balneola (phylum Bacteroidetes). On the basis of 16S rRNA gene sequence comparisons, and physiological and biochemical characteristics, the isolate represents a novel species for which the name Balneola alkaliphila sp. nov. is proposed. The type strain is CM41_14b(T) (=DSM 19538(T)=CIP 109603(T)=OOB 103(T))

Aerosol deposition and origin in French mountains estimated with soil inventories of 210Pb and artificial radionuclides

Radionuclide inventories were measured in soils from different French mountainous areas: Chaîne des Puys (Massif Central), Eastern Corsica, Jura, Montagne Noire, Savoie, Vosges and Rhine Valley. 210Pb soil inventories were used to estimate long-term (>75 yr) deposition of submicron aerosols. Whereas 210Pb total deposition is explained partly by wet deposition, as demonstrated by increase of 210Pb inventory with annual rainfall; a part of 210Pb in the soils of higher altitude is caused by orographic depositions. Using measurements of radionuclides coming from nuclear aerial weapon tests (137Cs and Pu isotopes), we were able to estimate the origin of aerosols deposited in high-altitude sites and to confirm the importance of occult deposition and feeder–seeder mechanism. Using a simple mass balance model, we estimate that occult deposition and feeder–seeder mechanisms account to more than 50% of total deposition of 210Pb and associated submicron aerosols in French altitude sites

Numérique : 1. Environnement : 0. Avec EcoInfo, changeons nos pratiques

National audience2015 : la France préside la 21e Conférence des Nations unies sur les changements climatiques 2015 : EcoInfo, récemment transformé en groupement de service, a 10 ans 2015 : les informaticiens se retrouvent aux JRES ! Une telle conjonction est une occasion unique pour imprimer dans ces JRES 2015 une empreinte Écoresponsable. Paris accueille la conférence sur le climat et nous, informaticiens, resterions en dehors des initiatives et des solutions pour lutter contre les bouleversements climatiques ? Non ! D'autant que les retours d'expérience se multiplient. Alors aujourd'hui, nous avons choisi de donner de la visibilité à vos bonnes pratiques, celles qui se mettent en place dans le monde de l'enseignement supérieur et de la recherche. Alors montez dans le train avec ceux qui y sont déjà et donnons ensemble un coup d'accélérateur à la réduction des émissions de gaz à effet de serre et autres polluants en tout genre ! Prise en compte de critères relatifs au développement durable dans nos achats, gestion de l'énergie de nos salles informatiques, éco-conception des data-centres quelle que soit leur taille, gestion des déchets : les frontières de nos métiers se déplacent. Le temps ou les informaticiens avaient les yeux rivés à l'écran et les mains collées au clavier est révolu, aujourd'hui, les bonnes pratiques émergent et commencent à se répandre. Aujourd'hui, des chercheurs n'ignorent plus les impacts des TICs sur l'environnement. Cette présentation se veut un catalyseur d'échanges autour d'un objectif commun : participer au mouvement COP21. JRES 2015 – Montpellier 1/

Thalassobaculum salexigens sp. nov., a new member of the family Rhodospirillaceae from the NW Mediterranean Sea, and emended description of the genus Thalassobaculum

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/00001/11201/7846.pdfInternational audienceA novel Gram-negative bacteria, named CZ41_10a(T), was isolated from coastal surface waters of the north-western Mediterranean Sea. Cells were motile, pleomorphic rods, 1.6 mum long and 0.7 mum wide and formed cream colonies on marine agar medium. The G+C content of the genomic DNA was 65 mol%. Phylogenetic analysis of 16S rRNA gene sequences placed the new isolate in the genus Thalassobaculum, a member of the family Rhodospirillaceae, class Alphaproteobacteria. Unlike Thalassobaculum litoreum CL-GR58(T), its closest relative, strain CZ41_10a(T) was unable to grow anaerobically and did not exhibit nitrate reductase activity. On the basis of DNA-DNA hybridization, fatty acid content and physiological and biochemical characteristics, this isolate represents a novel species for which the name Thalassobaculum salexigens sp. nov. is proposed. The type strain is CZ41_10a(T) (=DSM 19539(T)=CIP 109604(T)=MOLA [corrected] 84(T)). An emended description of the genus Thalassobaculum is also given

Local behaviour of the solutions of the Chipot-Weissler equation

We study the local properties of positive solutions of the equation $-\Delta u=u^p-m|\nabla u|^q$ in a punctured domain $\Omega\setminus\{0\}$ of $\mathbb{R}^N$ or in a exterior domain $\mathbb{R}^N\setminus B_{r_0}$ in the range $\min\{p,q\}>1$ and $m>0$. We prove a series of a priori estimates depending $p$ and $q$, and of the sign of $q-\frac {2p}{p+1}$ and $q-p$. Using various techniques we obtain removability results for singular sets and we give a precise description of behaviour of solutions near an isolated singularity or at infinity in $\mathbb{R}^N$.Comment: 63 page