Slowly rotating black hole solutions in Horndeski gravity

We study black hole solutions at first order in the Hartle-Thorne slow-rotation approximation in Horndeski gravity theories. We derive the equations of motion including also cases where the scalar depends linearly on time. In the Hartle-Thorne formalism, all first-order rotational corrections are described by a single frame-dragging function. We show that the frame-dragging function is exactly the same as in general relativity for all known black hole solutions in shift symmetric Horndeski theories, with the exception of theories with a linear coupling to the Gauss-Bonnet invariant. Our results extend previous no-hair theorems for a broad class of Horndeski gravity theories.Comment: Fixed more typos found in proof. Matches version published in PR

Duncan Jones Moon: Do clones dream of uncopyrighted sheep?

Moon (Duncan Jones, 2009) quietly and silently bursts into a sci-fi dominated by F/X and the thrilling action by means of a visual treatment that prevents spectacular computer generated images from stepping up the narrative pulse. On the contrary, the film is based on a crafty man-made aesthetic that send the spectator back to the classics of science fiction. However, some of the main topics are also typical to late science fiction, especially cyberpunk, by the role played by corporations on the exploitation of men (or of beings that are in the dim limits of humane) through technology.Fil: Berti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Humanidades. Universidad Nacional de Córdoba. Instituto de Humanidades; ArgentinaFil: Torrano, María Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad. Universidad Nacional de Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; Argentin

Duncan Jones Moon: Do clones dream of uncopyrighted sheep?

Moon (Duncan Jones, 2009) quietly and silently bursts into a sci-fi dominated by F/X and the thrilling action by means of a visual treatment that prevents spectacular computer generated images from stepping up the narrative pulse. On the contrary, the film is based on a crafty man-made aesthetic that send the spectator back to the classics of science fiction. However, some of the main topics are also typical to late science fiction, especially cyberpunk, by the role played by corporations on the exploitation of men (or of beings that are in the dim limits of humane) through technology.Fil: Berti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Humanidades. Universidad Nacional de Córdoba. Instituto de Humanidades; ArgentinaFil: Torrano, María Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad. Universidad Nacional de Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; Argentin

San Cayetano e suas localidades menores, dinâmica sócio territorial e estratégias espaciais

Revista indizada en: Latindex, periódicos, sumarios.org y SEER.Resumen:Las pequeñas localidades del distrito de San Cayetano; Ochandio, Deferrari y Cristiano Muerto ubicadas en la provincia de Buenos Aires de la República Argentina, muestran desde su fundación y hasta mediados de los años cincuenta un proceso de ocupación natural del espacio, evidenciando crecimiento demográfico marcado por la necesidad de mano de obra demandada por la actividad agrícola-ganadera.A partir de 1970 el proceso de apertura de la economía argentina es acompañado por medidas del Estado que impactaron en la concentración de las tierras, su modo de explotación y la necesidad de mano de obra. Todo ello produce un estancamiento demográfico en las pequeñas localidades.Luego de la crisis del 2001 el accionar del Estado se observa en la innovación local asociada con la cooperación y el compromiso en querer evitar la desaparición de pueblos como Ochandio, política que se afirma a partir de un nuevo contexto político y social que se instaura hacia el 2003. De este modo ciertos fragmentos del espacio rural procuran transformarse manteniendo un equilibrio entre las funciones que han sido tradicionalmente rurales y otras que podríamos apuntar como nuevas. En este marco el objetivo consiste en reflexionar en torno a cuáles son los nuevos desafíos que la renovación de los vínculos urbano-rurales impone a la construcción de territorios más equitativos y sustentables en este caso en el espacio rural sancayetanense.Palabras clave: Pequeñas localidades. San Cayetano. CEPT. Planificación estratégica. Territorio.Fil: Berti, Graciela María. Universidad Nacional de Mar del Plata. Facultad de Humanidades. Departamento de Geografía. Centro de Investigaciones Geográficas Socio-ambientales; ArgentinaFil: Mikkelsen, Claudia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Instituto de Geografía, Historia y Ciencias Sociales. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto de Geografía, Historia y Ciencias Sociales; Argentina. Universidad Nacional de Mar del Plata. Facultad de Humanidades. Departamento de Geografía. Centro de Investigaciones Geográficas Socio-ambientales; Argentin

Unravelling Interlanguage Facts via Explainable Machine Learning

Native language identification (NLI) is the task of training (via supervised machine learning) a classifier that guesses the native language of the author of a text. This task has been extensively researched in the last decade, and the performance of NLI systems has steadily improved over the years. We focus on a different facet of the NLI task, i.e., that of analysing the internals of an NLI classifier trained by an \emph{explainable} machine learning algorithm, in order to obtain explanations of its classification decisions, with the ultimate goal of gaining insight into which linguistic phenomena ``give a speaker's native language away''. We use this perspective in order to tackle both NLI and a (much less researched) companion task, i.e., guessing whether a text has been written by a native or a non-native speaker. Using three datasets of different provenance (two datasets of English learners' essays and a dataset of social media posts), we investigate which kind of linguistic traits (lexical, morphological, syntactic, and statistical) are most effective for solving our two tasks, namely, are most indicative of a speaker's L1. We also present two case studies, one on Spanish and one on Italian learners of English, in which we analyse individual linguistic traits that the classifiers have singled out as most important for spotting these L1s. Overall, our study shows that the use of explainable machine learning can be a valuable tool for t

The role of convection in the existence of wavefronts for biased movements

We investigate a model, inspired by (Johnston et al., Sci. Rep., 7:42134, 2017), to describe the movement of a biological population which consists of isolated and grouped organisms. We introduce biases in the movements and then obtain a scalar reaction-diffusion equation which includes a convective term as a consequence of the biases. We focus on the case the diffusivity makes the parabolic equation of forward-backward-forward type and the reaction term models a strong Allee effect, with the Allee parameter lying between the two internal zeros of the diffusion. In such a case, the unbiased equation (i.e., without convection) possesses no smooth traveling-wave solutions; on the contrary, in the presence of convection, we show that traveling-wave solutions do exist for some significant choices of the parameters. We also study the sign of their speeds, which provides information on the long term behavior of the population, namely, its survival or extinction.Comment: 30 pages, 10 figure

The role of convection in the existence of wavefronts for biased movements

We investigate a model, inspired by Johnston et al. (2017) to describe the movement of a biological population which consists of isolated and grouped organisms. We introduce biases in the movements and then obtain a scalar reaction–diffusion equation that includes a convective term as a consequence of the biases. We focus on the case the diffusivity makes the parabolic equation of forward–backward–forward type and the reaction term models a strong Allee effect, with the Allee parameter lying between the two internal zeros of the diffusion. In such a case, the unbiased equation (i.e., without convection) possesses no smooth traveling-wave solutions; on the contrary, in the presence of convection, we show that traveling-wave solutions do exist for some significant choices of the parameters.We also study the sign of their speeds, which provides information on the long term behavior of the population, namely, its survival or extinction

Uniqueness and nonuniqueness of fronts for degenerate diffusion-convection reaction equations

We consider a scalar parabolic equation in one spatial dimension. The equation is constituted by a convective term, a reaction term with one or two equilibria, and a positive diffusivity which can however vanish. We prove the existence and several properties of traveling-wave solutions to such an equation. In particular, we provide a sharp estimate for the minimal speed of the profiles and improve previous results about the regularity of wavefronts. Moreover, we show the existence of an infinite number of semi-wavefronts with the same speed