Broad-band variability in accreting compact objects

Cataclysmic variable stars are in many ways similar to X-ray binaries. Both types of systems possess an accretion disk, which in most cases can reach the surface (or event horizon) of the central compact object. The main difference is that the embedded gravitational potential well in X-ray binaries is much deeper than those found in cataclysmic variables. As a result, X-ray binaries emit most of their radiation at X-ray wavelengths, as opposed to cataclysmic variables which emit mostly at optical/ultraviolet wavelengths. Both types of systems display aperiodic broad-band variability which can be associated to the accretion disk. Here, the properties of the observed X-ray variability in XRBs are compared to those observed at optical wavelengths in CVs. In most cases the variability properties of both types of systems are qualitatively similar once the relevant timescales associated with the inner accretion disk regions have been taken into account. The similarities include the observed power spectral density shapes, the rms-flux relation as well as Fourier-dependant time lags. Here a brief overview on these similarities is given, placing them in the context of the fluctuating accretion disk model which seeks to reproduce the observed variability.Comment: Invited talk and accepted for publication in Acta Polytechnica, Proceedings of "The Golden Age of Cataclysmic Variables and Related Objects II

Radio making waves in the italian diaspora: Public sphere, Mediatised sphericules and diasporic publics

The deterritorialised publics of diaspora are conceptually quite different from the homogenous nationally bound public originally conceived to participate in Habermas’ public sphere. However, with globalisation and parallel advances in media technologies the qualities of diasporic communication increasingly come to resemble miniature, globalised but culturally specific public spheres. The Italian diaspora’s use of radio in Australia provides a valuable case study of the ways in which mediatised public sphericules can promote multi-layered diasporic affiliations. The Italo-Australian diasporic public sphericule highlights media involvement in the formation of subnational, transnational and international cultural communities, while also highlighting the home and host nation participation and policing of these transnational formations

Outer disc edge: properties of low-frequency aperiodic variability in ultracompact interacting binaries

Flickering, and more specifically aperiodic broad-band variability, is an important phenomenon used in understanding the geometry and dynamics of accretion flows. Although the inner regions of accretion flows are known to generate variability on relatively fast time-scales, the broad-band variability generated in the outer regions has mostly remained elusive due to its long intrinsic variability time-scales. Ultracompact AM CVn systems are relatively small when compared to other accreting binaries and are well suited to search and characterize low-frequency variability. Here, we present the first low-frequency power spectral analysis of the ultracompact accreting white dwarf system SDSS J1908+3940. The analysis reveals a low-frequency break at ∼6.8 × 10−7 Hz in the time-averaged power spectrum as well as a second higher frequency component with characteristic frequency of ∼1.3 × 10−4 Hz. We associate both components with the viscous time-scales within the disc through empirical fits to the power spectrum as well as analytical fits using the fluctuating accretion disc model. Our results show that the low-frequency break can be associated with the outer disc regions of a geometrically thin accretion flow. The detection of the low-frequency break in SDSS J1908+3940 provides a precedent for further detection of similar features in other ultracompact accreting systems. More importantly, it provides a new observable that can help constrain simulations of accretion flows

Influence of Displacement Rate on Residual Shear Strength of Clays

Abstract This paper reports on the results of direct shear tests carried out under controlled displacement rate in the range of 10 -4 -10 2 mm/min, under different normal stresses, with different shear devices. The tests were carried out on a kaolin, a bentonite, their mixtures with sand at various percentages, and the clayey soil of the Costa della Gaveta earthflow. The tests were performed on specimens reconstituted with distilled water as well as with NaCl solutions at various concentrations. Positive rate effects were exhibited by mixtures with c.f. higher than 50% and, consistently, by the natural clayey soil the c.f. of which is about 50%. The residual shear strength increases significantly for shear displacement rate higher than about 1 mm/min. The rate effect increases with the pore solution concentration. The residual shear strength independence of displacement rate has been confirmed in the range 10 -6 - 10 -1 mm/min by the results of shear tests performed under controlled shear stress, with varying chemical conditions of the pore fluid

Broad Absorption Line Quasar catalogues with Supervised Neural Networks

We have applied a Learning Vector Quantization (LVQ) algorithm to SDSS DR5 quasar spectra in order to create a large catalogue of broad absorption line quasars (BALQSOs). We first discuss the problems with BALQSO catalogues constructed using the conventional balnicity and/or absorption indices (BI and AI), and then describe the supervised LVQ network we have trained to recognise BALQSOs. The resulting BALQSO catalogue should be substantially more robust and complete than BI- or AI-based ones.Comment: 5 pages, 3 figures, to appear in the proceedings of "Classification and Discovery in Large Astronomical Surveys", Ringberg Castle, 14-17 October 200

Philippe Minyana rencontre les apprentis acteurs et/ou metteurs en scène de Inventaires du Lycée Ledoux

La rencontre entre un auteur et une classe est toujours un événement exceptionnel mais un exercice délicat, à plus forte raison lorsque l'intervenant est Philippe Minyana et l'auditoire, les élèves d'une option théâtre, qui se collent à son texte le plus joué : Inventaires. L'exercice devient plus difficile encore lorsqu'il s'agit de commenter avec lui sa dernière création, Pièces, accueillie cet hiver au Nouveau Théâtre dans la mise en scène de Robert Cantarella. Néanmoins, pour ces lycéens,..

Reflexões acerca do corpo e da sexualidade da mulher na dança oriental: comparativos entre Brasil-Egito sob a ótica foucaultiana

Art is classified through the ages, from the most remote, in the most distinct artistic characteristics, as a way of looking at the world. Among the most appreciated arts, the art of dance, present since the earliest civilizations, endures in modern times, enchanting generations. Through dance, whatever the style, one speaks, writes, draws, dreams, utilizing the body. The art of dance enhances bodily experiences in different social organizations. Its importance is in force in every epoch of history and is so unique that it changes and changes, and has been present since the earliest civilizations. The aim is to give the subject the opportunity in the field of sensitivities, based on dance, allowing him to experience a cognitive / affective experience, providing disruption in the way of reading / thinking and acting, about himself, the other and the world in an ethical and reflective way. In this way, the referring qualitative research sought to analyze the similarities and differences of the woman's body and sexuality in oriental dance in Brazil and Egypt through thematic analysis. The expected results signal an improvement in the ways of dancing in a pleasurable and critical way with greater emotional involvement, signaling the creation of an environment of spontaneity and creativity, allowing it to immerse itself in body language, enabling the construction and reconstruction of the gaze, the stimulation of the body. imagination, self-affirmation and autonomy, in addition to getting used to the existence of coexistence of form. In this sense, art can be innovative as it unfolds into a life project, in the (re) construction of new subjectivities impacting new modes of existence.El arte se clasifica a través de las edades, desde las más remotas, en las características artísticas más distintas, como una forma de mirar el mundo. Entre las artes más apreciadas, el arte de la danza, presente desde las civilizaciones más antiguas, perdura en los tiempos modernos, encantando a generaciones. A través de la danza, sea cual sea el estilo, hablamos, escribimos, dibujamos, soñamos, usando el cuerpo. El arte de la danza potencia las experiencias corporales en diferentes organizaciones sociales. Su importancia está presente en cada época de la historia y es tan singular que se modifica y transforma, estando presente desde las civilizaciones más antiguas. Se pretende dar al sujeto la oportunidad en el campo de las sensibilidades, desde la danza, permitiéndole vivir una experiencia cognitivo / afectiva aportando disrupción en la forma de leer / pensar y actuar, sobre sí mismo, el otro y el mundo de forma ética y reflexiva. . De esta manera, la investigación cualitativa referente buscó analizar las similitudes y diferencias del cuerpo y la sexualidad de la mujer en la danza oriental en Brasil y Egipto a través del análisis temático. Los resultados esperados señalan una mejora en las formas de bailar de manera placentera y crítica con mayor implicación emocional, señalan la creación de un ambiente de espontaneidad y creatividad que le permite involucrarse con el lenguaje corporal, posibilitar la construcción y reconstrucción de la mirada, la estimulación de imaginación, autoafirmación y autonomía, además de acostumbrarse a la existencia de la coexistencia de formas. En este sentido, el arte puede ser innovador cuando se despliega en un proyecto de vida, en la (re) construcción de nuevas subjetividades, impactando nuevos modos de existencia.A arte se classifica por meio dos tempos, desde os mais remotos, nas mais distintas características artísticas, como forma de se olhar o mundo. Dentre as artes mais apreciadas, a arte da dança, presente desde as mais antigas civilizações, perdura nos tempos modernos, encantando gerações. Por meio da dança, seja qual for o estilo, fala-se, escreve-se, desenha-se, sonha-se, utilizando o corpo. A arte da dança potencializa as experiências corporais nas diferentes organizações sociais. A sua importância se faz vigente em cada época da história e é tão singular que se modifica e se transforma, seguindo presente desde as mais antigas civilizações. Pretende-se oportunizar ao sujeito no campo das sensibilidades, a partir da dança, permitindo-o a vivenciar uma experiência cognitiva/afetiva proporcionando disrupção no modo de ler/pensar e agir, sobre si, o outro e o mundo de forma ética e reflexiva. Deste modo, a referente pesquisa qualitativa buscou analisar as semelhanças e diferenças do corpo e da sexualidade da mulher na dança oriental no Brasil e no Egito por meio da análise temática. Os resultados esperados sinalizam para uma melhoria dos modos de dançar de forma prazerosa e crítica com maior envolvimento emocional, sinalizam a criação do ambiente de espontaneidade e criatividade permitindo-o a se embrenhar pela linguagem corporal, possibilita construção e reconstrução do olhar, a estimulação da imaginação, autoafirmação e autonomia, além de se habituar à existência de convivência de forma. Nesse sentido, a arte pode ser inovadora ao se desdobrar para um projeto de vida, na (re)construção de novas subjetividades, impactando novos modos de existência

Entretenimento ou jornalismo? Uma análise sobre o gênero televisivo do programa CQC

Desde que surgiu no Brasil, em 2008, o programa Custe o Que Custar tem causado muita polêmica. Da criação até agora o programa tem mostrado uma grande relevância na sociedade, já que a audiência cresce a cada temporada. Este trabalho de conclusão do curso de jornalismo tem como objetivo definir o gênero televisivo, de acordo com seus telespectadores, em que o programa se encaixa