Approximate likelihood inference in generalized linear latent variable models based on integral dimension reduction

Latent variable models represent a useful tool for the analysis of complex data when the constructs of interest are not observable. A problem related to these models is that the integrals involved in the likelihood function cannot be solved analytically. We propose a computational approach, referred to as Dimension Reduction Method (DRM), that consists of a dimension reduction of the multidimensional integral that makes the computation feasible in situations in which the quadrature based methods are not applicable. We discuss the advantages of DRM compared with other existing approximation procedures in terms of both computational feasibility of the method and asymptotic properties of the resulting estimators.Comment: 28 pages, 3 figures, 7 table

The Effects of Galaxy Shape and Rotation on the X-ray Haloes of Early-Type Galaxies

We present a detailed diagnostic study of the observed temperatures of the hot X-ray coronae of early-type galaxies. By extending the investigation carried out in Pellegrini (2011) with spherical models, we focus on the dependence of the energy budget and temperature of the hot gas on the galaxy structure and internal stellar kinematics. By solving the Jeans equations we construct realistic axisymmetric three-component galaxy models (stars, dark matter halo, central black hole) with different degrees of flattening and rotational support. The kinematical fields are projected along different lines of sight, and the aperture velocity dispersion is computed within a fraction of the circularized effective radius. The model parameters are chosen so that the models resemble real ETGs and lie on the Faber-Jackson and Size-Luminosity relations. For these models we compute T_* (the stellar heating contribution to the gas injection temperature) and T_gm (the temperature equivalent of the energy required for the gas escape). In particular, different degrees of thermalisation of the ordered rotational field of the galaxy are considered. We find that T_* and T_gm can vary only mildly due to a pure change of shape. Galaxy rotation instead, when not thermalised, can lead to a large decrease of T_*; this effect can be larger in flatter galaxies that can be more rotationally supported. Recent temperature measurements T_x, obtained with Chandra, are larger than, but close to, the T_* values of the models, and show a possible trend for a lower T_x in flatter and more rotationally supported galaxies; this trend can be explained by the lack of thermalisation of the whole stellar kinetic energy. Flat and rotating galaxies also show lower L_x values, and then a lower gas content, but this is unlikely to be due to the small variation of T_gm found here for them.Comment: 16 pages, 7 figures, accepted for publication in MNRA

The "Canone Inverso": when tobacco was not so bad. A Look Back at the Primordial Debate on the tobacco effects in the Occupational Medicine

AIM: The article provides an overview on the beginning and evolutions of medical observations on tobacco induced diseases between Eighteenth and Nineteenth century. METHODS: By searching for historical medical literature, first studies on tobacco-induced diseases focused on production risks rather than on adverse effects that the use of tobacco has for the human health. RESULTS: The approach induced first eighteenth-century authors to define this substance as a non-pathogenic and, consequently, not to consider tobacco factories dangerous for health workers. In those years, tobacco was employed in therapy as a stimulant treatment and it was considered harmless and even healthy and preventive of several acute diseases. CONCLUSIONS: Authors will show that studies on pathogenic effects of smoking will only start around late nineteenth century, when the idea of the healthiness of tobacco industry was already supported

The 'Foce' monumental cemetery in Sanremo: mirror of the city as outstanding tourist destination during the Belle Epoque (1880-1915)

The monumental cemetery of Sanremo, was founded in 1838 and now counts about 2000 graves, one third of which belongs to foreigners, evidences of the city as outstanding tourist destination. The city with a good climate was also choosen for the recovery from the disease of chest by many people, even by Maria Alessandrovna, Csarina of Russia. Many important people came to Sanremo from all over the world and sometimes here passed by and were buried: people like the painter Edward Lear, the anatomist Arthur Hill Hassal, Lady Caroline Giffard Phillipson, Prussian nobles, a good number of Russian aristocrats, and many others..

Compactifying the image of the Abel map

Let $\alpha_X^{\underline d}$ be the Abel map of multidegree $\underline d$ of a singular curve $X$ of genus $g$. We describe the closure of ${\rm Im}\alpha_X^{\underline d}$ inside Caporaso's compactified Jacobian $\bar{P_X^d}$ for irreducible curves, curves of compact type and binary curves