A kinematic study of the Taurus-Auriga T association

Aims: This is the first paper in a series dedicated to investigating the kinematic properties of nearby associations of young stellar objects. Here we study the Taurus-Auriga association, with the primary objective of deriving kinematic parallaxes for individual members of this low-mass star-forming region. Methods: We took advantage of a recently published catalog of proper motions for pre-main sequence stars, which we supplemented with radial velocities from various sources found in the CDS databases. We searched for stars of the Taurus-Auriga region that share the same space velocity, using a modified convergent point method that we tested with extensive Monte Carlo simulations. Results: Among the sample of 217 Taurus-Auriga stars with known proper motions, we identify 94 pre-main sequence stars that are probable members of the same moving group and several additional candidates whose pre-main sequence evolutionary status needs to be confirmed. We derive individual parallaxes for the 67 moving group members with known radial velocities and give tentative parallaxes for other members based on the average spatial velocity of the group. The Hertzsprung-Russell diagram for the moving group members and a discussion of their masses and ages are presented in a companion paper.Comment: accepted for publication by A&

On the dual graph of Cohen-Macaulay algebras

Given a projective algebraic set X, its dual graph G(X) is the graph whose vertices are the irreducible components of X and whose edges connect components that intersect in codimension one. Hartshorne's connectedness theorem says that if (the coordinate ring of) X is Cohen-Macaulay, then G(X) is connected. We present two quantitative variants of Hartshorne's result: 1) If X is a Gorenstein subspace arrangement, then G(X) is r-connected, where r is the Castelnuovo-Mumford regularity of X. (The bound is best possible; for coordinate arrangements, it yields an algebraic extension of Balinski's theorem for simplicial polytopes.) 2) If X is a canonically embedded arrangement of lines no three of which meet in the same point, then the diameter of the graph G(X) is not larger than the codimension of X. (The bound is sharp; for coordinate arrangements, it yields an algebraic expansion on the recent combinatorial result that the Hirsch conjecture holds for flag normal simplicial complexes.)Comment: Minor changes throughout, Remark 4.1 expanded, to appear in IMR

Sustainability in the restoration and management of the historic architecture in Palermo

This research investigates the energy and environmental sustainability in the restoration and conservation of historic buildings. It focuses on the architectural heritage of Palermo, which can be a significant case study for the Mediterranean area. Its objective is to analyse the current energy performance of this historic architecture and its potential for energy improvement. Therefore, it aims at proposing a methodology to combine the enhancement of energy and environmental performances of the historic architecture of Palermo with the need of its material and aesthetic conservation, in the frame of the current regulations

The "High" and "Low" - Sirak Skitnik's Views on Art in the Space of Everyday Life

The text (part of the book by Irina Genova “Modern Art in Bulgaria: First Histories and Present Narratives beyond the Paradigm Modernity”, 2013) discuss critical articles by Sirak Skitnik concerning the role of the artist in the age of evolving industry. Special interest represents a growing tension between the self confidence of art as autonomous, and the forms of mass culture

The Spectator: Changes in the Situation. Between the Expert Spectator and Visual Literacy

The text discusses the fundamental changes in the situation of the art spectator (lover or / and expert) after the moment of invention of the art reproduction and, later, after the development of digital images and internet