1,643 research outputs found

    Impact of an AGN featureless continuum on estimation of stellar population properties

    Full text link
    The effect of the featureless power-law (PL) continuum of an active galactic nucleus (AGN) on the estimation of physical properties of galaxies with optical population spectral synthesis (PSS) remains largely unknown. With this in mind, we fit synthetic galaxy spectra representing a wide range of galaxy star formation histories (SFHs) and including distinct PL contributions of the form FΜ∝Μ−αF_{\nu} \propto \nu^{-\alpha} with the PSS code STARLIGHT to study to which extent various inferred quantities (e.g. stellar mass, mean age, and mean metallicity) match the input. The synthetic spectral energy distributions (SEDs) computed with our evolutionary spectral synthesis code include an AGN PL component with 0.5≀α≀20.5 \leq \alpha \leq 2 and a fractional contribution 0.2≀xAGN≀0.80.2 \leq x_{\mathrm{AGN}} \leq 0.8 to the monochromatic flux at 4020 \AA. At the empirical AGN detection threshold xAGN≃0.26x_{\mathrm{AGN}}\simeq 0.26 that we previously inferred in a pilot study on this subject, our results show that the neglect of a PL component in spectral fitting can lead to an overestimation by ∌\sim2 dex in stellar mass and by up to ∌\sim1 and ∌\sim4 dex in the light- and mass-weighted mean stellar age, respectively, whereas the light- and mass-weighted mean stellar metallicity are underestimated by up to ∌\sim0.3 and ∌\sim0.6 dex, respectively. Other fitting set-ups including either a single PL or multiple PLs in the base reveal, on average, much lower unsystematic uncertainties of the order of those typically found when fitting purely stellar SEDs with stellar templates, however, reaching locally up to ∌\sim1, 3 and 0.4 dex in mass, age and metallicity, respectively. Our results underscore the importance of an accurate modelling of the AGN spectral contribution in PSS fits as a minimum requirement for the recovery of the physical and evolutionary properties of stellar populations in active galaxies.Comment: 18 pages, 22 figures, accepted for publication in A&

    Time Management of Heterogeneous Distributed Simulation

    Get PDF
    Cyber-physical systems (CPS), by their very nature, mix continuous and discrete behavior and are modeled by heterogeneous components. Formal analysis cannot always handle such complex systems and simulation is a necessary step. In particular, distributed simulation is very useful for the validation of CPS for two main reasons: either the CPS itself is distributed (e.g., a fleet of UAVs) or the CPS is too complex and/or has too much models (e.g., an aircraft). We discuss in this paper the impact of distributing the simulation of a system: which are the rules that must be applied to guarantee a correct behavior between the different simulators? If a centralized simulation already exists (using Discrete Event simulation), which hypothesis must be made for the Distributed Discrete Event simulation? The co-simulation framework used and discussed in this work is Ptolemy-HLA. It allows a Ptolemy model to be distributed using the high-level architecture (HLA) standard

    La Compétitivité passe aussi par la fiscalité:Nos idées pour adapter la loi de finances 2013 au pacte de compétitivité

    Get PDF
    Fruit d’une discussion collective, cette note prĂ©sente les propositions de la Fondation pour rĂ©ajuster les dispositions de la loi de finances 2013 afin de les rendre cohĂ©rentes avec les recommandations du pacte de compĂ©titivitĂ©. Ce texte est issu d’une conversation entre Aldo Cardoso, membre du Conseil de surveillance de la Fondation pour l’innovation politique, Michel Didier, Professeur honoraire au CNAM et prĂ©sident de Coe-Rexecode, Bertrand Jacquillat, Professeur Ă  Sciences Po et prĂ©sident d’AssociĂ©s en Finance, Dominique ReyniĂ© et GrĂ©goire Sentilhes, prĂ©sident de NextStage, des JournĂ©es de l’Entrepreneur et du G20 YES en France

    A corpus of European Portuguese child and child-directed speech

    Get PDF
    We present a corpus of child and child-directed speech of European Portuguese. This corpus results from the expansion of an already existing database (Santos, 2006). It includes around 52 hours of child-adult interaction and now contains 27,595 child utterances and 70,736 adult utterances. The corpus was transcribed according to the CHILDES system (Child Language Data Exchange System) and using the CLAN software (MacWhinney, 2000). The corpus itself represents a valuable resource for the study of lexical, syntax and discourse acquisition. In this paper, we also show how we used an existing part-of-speech tagger trained on written material (Généreux, Hendrickx & Mendes, 2012) to automatically lemmatize and tag child and child-directed speech and generate a line with part-of-speech information compatible with the CLAN interface. We show that a POS-tagger trained on the analysis of written language can be exploited for the treatment of spoken material with minimal effort, with only a small number of written rules assisting the statistical model.info:eu-repo/semantics/publishedVersio

    Viabilidade do uso de RCD proveniente da geração dos concretos convencional e de alta resistĂȘncia atravĂ©s da utilização do jigue como agente do beneficiamento

    Get PDF
    O presente trabalho avaliou a viabilidade do uso de ResĂ­duos de Construção e Demolição (RCD) provenientes da geração de dois traços de concretos distintos. Um Concreto Convencional-CC (traço em massa:1:2,94:3,56; a/c:0,61) utilizando cimento CP IV 32 e outro concreto de Alta ResistĂȘncia-CAR (traço em massa:1:1,11:2; a/c: 0,22; com adição, aditivo e pĂł xadrez vermelho) utilizando cimento CP V-ARI. ApĂłs 28 dias de cura, 3 corpos de prova de cada traço foram submetidos ao ensaio de resistĂȘncia a compressĂŁo axial apresentando em mĂ©dia para CC 21,02 MPa e para CAR 95,09 MPa. Os materiais de ambos os traços foram cominuĂ­dos atravĂ©s de um britador de mandĂ­bula ajustado para granulometria menor que 19,1 mm e retido em 4,75 mm. Com isso, foram realizados ensaios de granulometria de cada traço, e misturados em volumes iguais para o beneficiamento do material. Os primeiros ensaios foram realizados no jigue a ar, porĂ©m os resultados apresentados foram insatisfatĂłrios. Para o jigue Ă  ĂĄgua ocorreu uma separação visĂ­vel de 3 estĂĄgios (Topo, Meio e Fundo) Utilizando somente as camadas de topo e fundo, os agregados reciclados de concreto (ARC) foram utilizados para confecção de novos concretos. Os resultados apontaram que a aplicação do jigue Ă  ĂĄgua possibilitou um beneficiamento do material para uso como agregado graĂșdo. Os ensaios de resistĂȘncia Ă  compressĂŁo, os concretos produzidos com a camada de fundo do agregado reciclado superaram os produzidos com agregado natural. Nos ensaios de mĂłdulo de elasticidade, os concretos com o agregado natural exibiram resultados melhores do que os reciclados do topo, porĂ©m para os concretos produzidos com os agregados do fundo, os mĂłdulos se igualaram aos dos concretos com agregado natural. No ensaio de absorção, o concreto reciclado mostrou uma absorção maior que o concreto natural. Para a carbonatação os concretos com agregados reciclados tiveram melhores resultados. As avaliaçÔes dos efeitos foram concludentes para o uso do jigue no beneficiamento do agregado reciclado de concreto (ARC).The present work evaluates the feasibility of using Construction and Demolition Waste (CDW) generated by two different concrete mixes, one being aconventional concrete-CC (mix:mass: 1:2, 94:3, 56, w/c: 0,61) using CP IV 32, and another being a high strength concrete - CAR (mix:mass: 1:1, 11:2, w/c: 0.22), with the addition of additive and red pigment) using cement CP V-ARI. After 28 days of curing, three test specimens of each concrete were submitted to the resistance test, presenting 21.02 MPa on average for CC and 95.09 Mpa for CAR. The materials of both mixes were comminuted by jaw crusher, and sieved to a particle size range of -19.1 mm + 4.75 mm. With this, granulometry, tests of each concrete were performed and the concretes were mixed in equal volumes for the application of the material processing. The first tests were performed by air jig, but the results were found to be unsatisfactory A visible separation of 3 stages (Top, Middle and Bottom) was achieved by use of water jig. Using only the top and bottom layers, Recycled Concrete Aggregates (RCA) was added for the creation of new concrete. The results indicate that the application of the water jig made it possible to improve the material for use as a large aggregate. For the compressive strength tests, the concretes produced with the bottom layer of the recycled aggregate surpassed those produced with natural aggregate. In the modulus of elasticity tests, concretes with the natural aggregate presented better results than those recycled from the top. For the concretes produced with the bottom aggregates, the modules matched that of the concrete with natural aggregate. In the absorption test the recycled concrete showed a higher absorption than the natural concrete. For carbonation the recycled had better results. An evaluation of the results concludes in favor of the use of water jig for the recycling of concrete aggregates (RCA)

    A corpus of European Portuguese child and child-directed speech

    Get PDF
    We present a corpus of child and child-directed speech of European Portuguese. This corpus results from the expansion of an already existing database (Santos, 2006). It includes around 52 hours of child-adult interaction and now contains 27,595 child utterances and 70,736 adult utterances. The corpus was transcribed according to the CHILDES system (Child Language Data Exchange System) and using the CLAN software (MacWhinney, 2000). The corpus itself represents a valuable resource for the study of lexical, syntax and discourse acquisition. In this paper, we also show how we used an existing part-of-speech tagger trained on written material (Généreux, Hendrickx & Mendes, 2012) to automatically lemmatize and tag child and child-directed speech and generate a line with part-of-speech information compatible with the CLAN interface. We show that a POS-tagger trained on the analysis of written language can be exploited for the treatment of spoken material with minimal effort, with only a small number of written rules assisting the statistical model.info:eu-repo/semantics/publishedVersio
    • 

    corecore