A review of elliptical and disc galaxy structure, and modern scaling laws

A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

Profiling cardiac resynchronization therapy patients: responders, non-responders and those who cannot respond-The good, the bad and the ugly?

Cardiac resynchronization therapy (CRT) is an effective option for the management of heart failure (HF) patients with left ventricular systolic dysfunction and prolongation of the QRS interval. Unfortunately, a variable proportion of eligible patients fail to benefit from this treatment, the so-called "non-responders". Despite intensive investigations aimed at identifying reliable diagnostic tools, additional to standard criteria, for the selection of responders, partly due to the complexity and multi-factorial nature of the mechanism underlying response, no conclusive evidence is currently available about which of the many variables assessed may predict individual response and should be included in selection criteria. Accordingly, even if labeled as a non-responder, a patient should receive a CRT device being the certain risk of withholding the treatment more consistent than the potential risk of being a non-responder. However, a possible third profile of patients along with responders and non-responders is emerging consisting of a limited subset of individuals, mainly among those with HF of ischemic aetiology, who simply do not possess the anatomical requisite for conventional biventricular pacing to be effective. Such patients may be referred to as those who cannot respond to CRT and their identification is potentially feasible by integrating non-invasive imaging findings and of clinical relevance in the definition of the therapeutic strategy. In conclusion, this review will provide an analysis of gathered data about the selection of candidates to CRT beyond responders and non-responders with the perspective of the potential characterization of patients who cannot respond to CRT