A new HW Vir binary from the Palomar Transient Factory: PTF1 J072455.75+125300.3 - An eclipsing subdwarf B binary with a M-star companion

We report the discovery of an eclipsing binary -- PTF1 J072456$+$125301-- composed of a subdwarf B (sdB) star ($g'=17.2^m$) with a faint companion. Subdwarf B stars are core helium-burning stars, which can be found on the extreme horizontal branch. About half of them reside in close binary systems, but few are known to be eclipsing, for which fundamental stellar parameters can be derived.\newline We conducted an analysis of photometric data and spectra from the Palomar 60'' and the 200" Hale telescope respectively. A quantitative spectral analysis found an effective temperature of $T_{\text{eff}}=33900\pm350$\,K, log g = $5.74\pm0.08$ and log($n_{\text{He}}/n_{\text{H}}) = -2.02 \pm0.07$, typical for an sdB star. The companion does not contribute to the optical light of the system, except through a distinct reflection effect. From the light curve an orbital period of 0.09980(25)\,d and a system inclination of 83.56\pm0.30\,^{\circ} were derived. The radial velocity curve yielded an orbital semi-amplitude of K_1=95.8\pm 8.1\,\text{km s^{-1}}. The mass for the M-type dwarf companion is $0.155\pm0.020\,M_{\odot}$. PTF1\,J072456$+$125301 has similar atmospheric parameters to those of pulsating sdB stars (V346 Hya stars). Therefore it could be a high-priority object for asteroseismology, if pulsations were detected such as in the enigmatic case of NY Vir.Comment: Accepted to A&A, 7pages, 4 figure

An Approximate Maximum Common Subgraph Algorithm for Large Digital Circuits

This paper presents an approximate Maximum Common Subgraph (MCS) algorithm, specifically for directed, cyclic graphs representing digital circuits. \ud Because of the application domain, the graphs have nice properties: they are very sparse; have many different labels; and most vertices have only one predecessor. The algorithm iterates over all vertices once and uses heuristics to find the MCS. It is linear in computational complexity with respect to the size of the graph. Experiments show that very large common subgraphs were found in graphs of up to 200,000 vertices within a few minutes, when a quarter or less of the graphs differ. The variation in run-time and quality of the result is low

Intelligent multimedia indexing and retrieval through multi-source information extraction and merging

This paper reports work on automated meta-data\ud creation for multimedia content. The approach results\ud in the generation of a conceptual index of\ud the content which may then be searched via semantic\ud categories instead of keywords. The novelty\ud of the work is to exploit multiple sources of\ud information relating to video content (in this case\ud the rich range of sources covering important sports\ud events). News, commentaries and web reports covering\ud international football games in multiple languages\ud and multiple modalities is analysed and the\ud resultant data merged. This merging process leads\ud to increased accuracy relative to individual sources

Stratégies de gestion individuelle de la salinité dans le périmètre irrigué du Bas Cheliff : cas du périmètre de Ouarizane

International audienceDans cet article, l'unité d'étude est le périmètre de Ouarizane, une entité homogène de 6 000 ha à l'intérieur du périmètre irrigué du Bas Cheliff. On y décrit les pratiques de gestion de la salinité et on tente de comprendre les modes d'adaptation des agriculteurs. Des enquêtes réalisées sur une quarantaine d'exploitations agricoles ont permis de distinguer cinq classes selon les cultures. On montre que les agriculteurs adaptent les cultures au niveau de salinité : agrumes, oliviers, grenadiers et autres cultures dites sensibles en amont, dans les parcelles peu salées, et artichauts et cucurbitacées en aval, dans les zones plus salées. Des modes de gestion individuels de la salinité ont été identifiés : choix par les locataires de parcelles non salées, rotation céréales - artichaut - melon pour les maraîchers, introduction de variétés d'artichaut importées, etc. La confrontation des enquêtes aux mesures (CE, SAR, pH) a permis de conclure à une perception différenciée de la salinité : les agriculteurs situés à l'aval, qui sont plus directement concernés par les effets des sels, ont développé des stratégies collectives de choix variétal d'artichaut, de pompage et d'encadrement technique alors que ceux de l'amont n'ont pas encore réagi aux effets du remplacement de l'eau de surface par l'eau souterraine