7,641 research outputs found
La blogosfera degli elettori: la community di Grillo
No full textProfilo linguistico e retorico delle scelte espressive adottate nel blog di Beppe Grillo
Projected central dark matter fractions and densities in massive early-type galaxies from the Sloan Digital Sky Survey
No full textWe investigate in massive early-type galaxies the variation of their two-dimensional central fraction of dark over total mass and dark matter density as a function of stellar mass, central stellar velocity dispersion, effective radius, and central surface stellar mass density. We use a sample of approximately 1.7 × 105 galaxies from the Sloan Digital Sky Survey Data Release Seven (SDSS DR7) at redshift smaller than 0.33. We apply conservative photometric and spectroscopic cuts on the SDSS DR7 and the MPA/JHU value-added galaxy catalogs, to select galaxies with physical properties similar to those of the lenses studied in the Sloan Lens ACS Survey. The values of the galaxy stellar and total mass projected inside a cylinder of radius equal to the effective radius are obtained, respectively, by fitting the SDSS multicolor photometry with stellar population synthesis models, under the assumption of a Chabrier stellar initial mass function (IMF), and adopting a one-component isothermal total mass model with effective velocity dispersion approximated by the central stellar velocity dispersion. The plausibility of an isothermal model to represent the galaxy total mass distribution is supported by independent gravitational lensing and stellar-dynamical analyses performed in the lens subsample, which is found here to represent nicely the entire galaxy sample. We find that within the effective radius the stellar mass estimates differ from the total ones by only a relatively constant proportionality factor. In detail, we observe that the values of the projected fraction of dark over total mass and the logarithmic values of the central surface dark matter density (measured in M⊙ kpc-2) have almost Gaussian probability distribution functions, with median values of 0.64+0.080.11 and 9.1+0.2-0.2, respectively. We discuss the observed correlations between these quantities and other galaxy global parameters and show that our results disfavor an interpretation of the tilt of the fundamental plane in terms of differences in the galaxy dark matter content and give useful information on the possible variations of the galaxy stellar IMF and dark matter density profile. Finally, we provide some observational evidence on the likely significant contribution of dry minor mergers, feedback from active galactic nuclei, and/or coalescence of binary black holes on the formation and evolution of massive early-type galaxies
Kirillov structures and reduction of Hamiltonian systems by scaling and standard symmetries
No full textIn this paper, we discuss the reduction of symplectic Hamiltonian systems by scaling and standard symmetries which commute. We prove that such a reduction process produces a so-called Kirillov Hamiltonian system. Moreover, we show that if we reduce first by the scaling symmetries and then by the standard ones or in the opposite order, we obtain equivalent Kirillov Hamiltonian systems. In the particular case when the configuration space of the symplectic Hamiltonian system is a Lie group , which coincides with the symmetry group, the reduced structure is an interesting Kirillov version of the Lie–Poisson structure on the dual space of the Lie algebra of . We also discuss a reconstructionprocess for symplectic Hamiltonian systems which admit a scaling symmetry. All the previous results are illustrated in detail with some interesting examples.Fil: Bravetti, A.. Universidad Nacional Autónoma de México; MéxicoFil: Grillo, Sergio Daniel. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Marrero, J. C.. Universidad de La Laguna; EspañaFil: Padrón, E.. Universidad de La Laguna; Españ
Entrevista com Sheila Grillo: Análise de Discursos Comparativa no Brasil
No full textNo dia 12 do mês de abril de 2022, Sheila Vieira de Camargo Grillo, professora livre-docente e pesquisadora da FFLCH/USP, recebeu-nos, gentilmente, em sua casa, para a realização desta entrevista, por meio da qual pudemos ouvir a autora a respeito de alguns pontos essenciais de uma nova abordagem de investigação científica no Brasil, a Análise de Discursos Comparativa ou Análise do Discurso Contrastiva (denominação adotada na França, país de origem da abordagem). A professora Sheila Grillo, a partir das perguntas que lhe fizemos, discorreu, dentre outros aspectos, sobre o surgimento dos princípios epistemológicos da abordagem em nosso país, citou alguns de seus importantes eventos ocorridos até o presente momento, bem como nos falou acerca da importância de trabalhos desenvolvidos entre ela e demais pesquisadores do Grupo de Pesquisa Diálogo (CNPq/USP) com professores e pesquisadores do grupo CLESTHIA – axe sens et discours, da Université Sorbonne Nouvelle, Paris 3. Desse modo, aproveitamos o espaço para agradecer à entrevistada pelo acolhimento e pelas informações disponibilizadas. Convidamos o leitor da Linha D’Água a apreciar o resultado deste trabalho.On April 12, 2022, Sheila Vieira de Camargo Grillo, a professor and researcher at the Faculty of Philosophy, Languages and Literature, and Human Sciences of the University of São Paulo, kindly welcomed us to her home for this interview. We were able to hear the author talk about the essential points of a new approach to scientific investigation in Brazil, Comparative Discourse Analysis or Contrastive Discourse Analysis (the name adopted in France, where it originated). Professor Sheila Grillo, based on the questions we asked, spoke about, among other topics, the emergence of the epistemological principles of Comparative Discourse Analysis in Brazil, mentioned some of the important events that have taken place until 2022, and also told us about the importance of the work carried out between herself and other researchers from the Diálogo Research Group (CNPq/USP) with professors and researchers at CLESTHIA - axe sens et discours, from Université Sorbonne Nouvelle, Paris 3. Thus, we take this opportunity to thank the interviewee for the welcoming reception and for the information provided. We invite the reader of Linha D\u27Água to appreciate the result of this work
Wind component estimation for UAS flying in turbulent air
No full textOne of the most important problem of autonomous flight for UAS is the wind identification, especially for small scale vehicles. This research focusses on an identification methodology based on the Extended Kalman Filter (EKF). In particular authors focus their attention on.the filter tuning problem. The proposed procedure requires low computational power, so it is very useful for UAS. Besides it allows a robust wind component identification even when, as it is usually, the measurement data set is affected by noticeable noises. (C) 2019 Elsevier Masson SAS. All rights reserved
El Grillo: periódico de variedades
No full text“El Grillo: periódico de variedades” fue una publicación que circuló en Popayán durante 1898. Su cabezote se acompañaba de un epígrafe de Rubén Darío que decía: “Y el grillo preludia su solo monótono en la única cuerda que está su violín. El periódico tuvo algunos cambios en su frecuencia y dirección, a saber: por un lado, la serie 2, fue publicada eventualmente (de forma irregular) y dirigida por Pedro A. Peña R. Por otro lado, la serie 3, fue dirigida por Daniel Gil Lemos de manera semanal y se oriento hacía el liberalismo radical y la crítica a los gobiernos de la Regeneración. En el número 15 de la serie 2, se informaba sobre: la falta de materiales para la impresión del periódico, la corrida de toros del 10 de abril de 1898 y el debate que se mantenía con el periódico “El Bien Público”.P2344
Once-in-a-lifetime event : Astronomers successfully predict a distant supernova replay in advance
No full textGravitational lensing, the deflection of light by gravity, has tremendously contributed over the past twenty years to our understanding of the mass distribution in galaxies and galaxy clusters and of the distant Universe. Gravitational lensing has demonstrated its great potential for future studies about the mysterious dark-matter and dark-energy mass components in the Universe. By exploiting the synergy between superb Hubble Space Telescope and Very Large Telescope data, an international group of astronomers have constructively worked together to obtain high-quality mass reconstructions of a massive cluster of galaxies and have provided the first-ever successful predictions of position, magnification and time delay of a distant lensed supernova, before it actually became visible
On the average density profile of dark-matter halos in the inner regions of massive early-type galaxies
No full textWe study a sample of 39 massive early-type lens galaxies at redshift z ≲ 0.3 to determine the slope of the average dark-matter density profile in the innermost regions. We keep the strong-lensing and stellar population synthesis modeling as simple as possible to measure the galaxy total and luminous masses. By rescaling the values of the Einstein radius and dark-matter projected mass with the values of the luminous effective radius and mass, we combine all the data of the galaxies in the sample. We find that between 0.3 and 0.9times the value of the effective radius the average logarithmic slope of the dark-matter projected density profile is -1.0 ± 0.2 (i.e., approximately isothermal) or -0.7 ± 0.5 (i.e., shallower than isothermal), if, respectively, a constant Chabrier or heavier, Salpeter-like stellar initial mass function is adopted. These results provide positive evidence of the influence of the baryonic component on the contraction of the galaxy dark-matter halos, compared to the predictions of dark-matter-only cosmological simulations, and open a new way to test models of structure formation and evolution within the standard ΛCDM cosmological scenario
Gli esordi dello "stil pietoso" di Angelo Grillo
No full textIl contributo analizza le prime raccolte liriche del monaco-poeta Angelo Grillo ("Rime spirituali" del 1589 e "Lagrime del Penitente" del 1593), andando in cerca di quegli elementi che preannunciano, sia pure all'interno di una retorica grave tardo-manierista, la svolta stilstica in senso barocco che caratterizzerà le raccolte successive (dai "Pietosi affetti" del 1595 in poi)
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