An elementary characterization of the Gini index

The Gini coefficient or index is perhaps one of the most used indicators of social and economic conditions. In this paper we characterize the Gini index as the unique function that satisfies the properties of scale invariance, symmetry, proportionality and convexity in similar rankings. Furthermore, we discuss a simpler way to compute it.Gini index, income inequality, axiomatization

The full Schwinger-Dyson tower for random tensor models

We treat random rank-$D$ tensor models as $D$-dimensional quantum field theories---tensor field theories (TFT)---and review some of their non-perturbative methods. We classify the correlation functions of complex tensor field theories by boundary graphs, sketch the derivation of the Ward-Takahashi identity and stress its relevance in the derivation of the tower of exact, analytic Schwinger-Dyson equations for all the correlation functions (with connected boundary) of TFTs with quartic pillow-like interactions.Comment: Proceedings: Corfu 2017 Training School "Quantum Spacetime and Physics Models

Study of stellar populations in the bulges of barred galaxies

We have obtained long-slit spectroscopy for a sample of 20 early-type barred galaxies to study the influence of bars in the building of galaxy bulges. Line strength indices were measured and used to derive age and metallicity gradients in the bulge region by comparing with stellar population models. The same analysis was also carried out with similar data of unbarred galaxies taken from the literature. The bulges of barred galaxies seem to be more metal rich, at a given velocity dispersion (sigma), than the bulges of unbarred galaxies, as measured by some metallicity sensitive indices. There are indications that the ratio of relative abundance of alpha-elements with respect to iron, [E/Fe], derived for the bulges of barred galaxies tend to lie above the values of the unbarred galaxies at a given sigma. The metallicity gradients for the majority of the bulges are negative, less metal rich towards the end of the bulge. The gradient values show a large scatter for galaxies with sigma below 150 km/s. The age distribution is related to the presence of bulge substructure such as a nuclear ring or an inner disk. The metallicity of both the bulge and the bar are very well correlated indicating a close link between the enrichment histories of both components. Bulges of barred early type galaxies might have suffered a different chemical enrichment compared to the bulges of unbarred galaxies of the same morphological type, same central velocity dispersion and low inclination angles. The hinted stellar populations differences separating the bulges of barred and unbarred galaxies and the strong link existing between the metallicity of the bulge and the presence of a bar points to scenarios were they both form simultaneously in processes leading to rapid and massive episodes of star formation, possibly linked to the bar formation.Comment: Accepted for publication in Astronomy and Astrophysic

Optimal domain of qq-concave operators and vector measure representation of qq-concave Banach lattices

Given a Banach space valued $q$-concave linear operator $T$ defined on a $\sigma$-order continuous quasi-Banach function space, we provide a description of the optimal domain of $T$ preserving $q$-concavity, that is, the largest $\sigma$-order continuous quasi-Banach function space to which $T$ can be extended as a $q$-concave operator. We show in this way the existence of maximal extensions for $q$-concave operators. As an application, we show a representation theorem for $q$-concave Banach lattices through spaces of integrable functions with respect to a vector measure. This result culminates a series of representation theorems for Banach lattices using vector measures that have been obtained in the last twenty years

INSA scientific activities in the space astronomy area

Support to Astronomy operations is an important and long-lived activity within INSA. Probably the best known (and traditional) INSA activities are those related with real-time spacecraft operations: Ground station maintenance and operation (Ground station engineers and operators); spacecraft and payload real-time operation (spacecraft and instruments controllers); computing infrastructure maintenance (operators, analysts) and general site services.In this paper, we'll show a different perspective, probably not so well-known, presenting some INSA recent activities at the European Space Astronomy Centre (ESAC) and NASA Madrid Deep Space Communication Complex (MDSCC) directly related to scientific operations. Basic lines of activity involved include: Operations support for science operations; system and software support for real time systems; technical administration and IT support; R \& D activities, radioastronomy (at MDSCC and ESAC) and scientific research projects. This paper is structured as follows: first, INSA activities in two ESA cornerstone astrophysics missions, XMM-Newton and Herschel, will be outlined. Then, our activities related to Science infrastructure services, represented by the Virtual Observatory (VO) framework and the Science Archives development facilities are briefly shown. Radio Astronomy activities will be described afterwards, and finally, a few research topics in which INSA scientists are involved will be also described.Comment: 6 pages. Highlights of Spanish Astrophysics V Proceedings of the VIII Scientific Meeting of the Spanish AstronomicalSociety (SEA) held in Santander, 7-11 July, 200

The geometry of L^p-spaces over atomless measure spaces and the Daugavet property

We show that $L^p$-spaces over atomless measure spaces can be characterized in terms of a $p$-concavity type geometric property that is related with the Daugavet property