Prospects for detection of very high-energy emission from GRB in the context of the external shock model

The detection of the 100 GeV-TeV emission by a gamma-ray burst (GRB) will provide an unprecedented opportunity to study the nature of the central engine and the interaction between the relativistic flow and the environment of the burst's progenitor. In this paper we show that there are exciting prospects of detecting from the burst by MAGIC high-energy (HE) emission during the early X-ray flaring activity and, later, during the normal afterglow phase. We also identify the best observational strategy, trigger conditions and time period of observation. We determine the expected HE emission from the flaring and afterglow phases of GRBs in the context of the external shock scenario and compare them with the MAGIC threshold. We find that an X-ray flare with the average properties of the class can be detected in the 100 GeV range by MAGIC, provided that z<0.7. The requested observational window with MAGIC should then start from 10-20 s after the burst and cover about 1000-2000 s. Furthermore, we demonstrate that there are solid prospects of detecting the late afterglow emission in the same energy range for most of the bursts with z<0.5 if the density of the external medium is n> a few cm^-3. In this case, the MAGIC observation shall extend to about 10-20 ks. We provide recipes for tailoring this prediction to the observational properties of each burst,in particular the fluence in the prompt emission and the redshift, thus allowing an almost real time decision procedure to decide whether to continue the follow-up observation of a burst at late times.Comment: 6 pages, 2 color figures, accepted for the pubblication in A&

Religion and Political Form: Carl Schmitt’s Genealogy of Politics as Critique of Habermas’s Post-secular Discourse

Jürgen Habermas's post-secular account is rapidly attracting attention in many fields as a theoretical framework through which to reconsider the role of religion in contemporary societies. This work seeks to go beyond Habermas's conceptualisation by placing the post-secular discourse within a broader genealogy of the relationships between space, religion, and politics. Drawing on the work of Carl Schmitt, the aim of this article is to contrast the artificial separation between private and public, religious and secular, state and church, and the logic of inclusion/exclusion on which modernity was established. Revisiting this genealogy is also crucial to illustrating, in light of Schmitt's political theory, the problems underlying Habermas's proposal, emphasising its hidden homogenising and universalist logic in an attempt to offer an alternative reflection on the contribution of religious and cultural pluralism within Western democracies

Future Needs in Mast Cell Biology.

The pathophysiological roles of mast cells are still not fully understood, over 140 years since their description by Paul Ehrlich in 1878. Initial studies have attempted to identify distinct "subpopulations" of mast cells based on a relatively small number of biochemical characteristics. More recently, "subtypes" of mast cells have been described based on the analysis of transcriptomes of anatomically distinct mouse mast cell populations. Although mast cells can potently alter homeostasis, in certain circumstances, these cells can also contribute to the restoration of homeostasis. Both solid and hematologic tumors are associated with the accumulation of peritumoral and/or intratumoral mast cells, suggesting that these cells can help to promote and/or limit tumorigenesis. We suggest that at least two major subsets of mast cells, MC1 (meaning anti-tumorigenic) and MC2 (meaning pro-tumorigenic), and/or different mast cell mediators derived from otherwise similar cells, could play distinct or even opposite roles in tumorigenesis. Mast cells are also strategically located in the human myocardium, in atherosclerotic plaques, in close proximity to nerves and in the aortic valve. Recent studies have revealed evidence that cardiac mast cells can participate both in physiological and pathological processes in the heart. It seems likely that different subsets of mast cells, like those of cardiac macrophages, can exert distinct, even opposite, effects in different pathophysiological processes in the heart. In this chapter, we have commented on possible future needs of the ongoing efforts to identify the diverse functions of mast cells in health and disease

Analysis of thermal field within an urban canyon with variable thermophysical characteristics of the building's walls.

In a typical urban configuration, a microclimatic analysis has been carried out. Using a CFD method, a N-S oriented urban street canyon, with a given H/W ratio, has been examined. The standard k–ε turbulence model has been used to simulate a three-dimensional flow field and to calculate the thermo-fluid dynamics parameters that characterize the street canyon. In this study has been analyzed the thermal flow field when the walls of the building change the properties of solar radiation absorption, in particular for α=0.2 and α=0.8. Solar radiation considered is that of 21/07 in Milan in two different hours: at 11:00 a.m. and at 02:00 p.m. The study shows the importance of the thermophysical properties of a wall, in the development of the thermal field and flow field. This is a very important topic, in terms of improvement of well-being and the quality of the air within the cities, through the choice of materials and colors of the facades of buildings.

Exact Local Bosonic Algorithm for Dynamical Quarks

We present an exact local bosonic algorithm for the simulation of dynamical fermions in lattice QCD. We show that this algorithm is a viable alternative to the Hybrid Monte Carlo algorithm.Comment: 3 pages, 1 PostScript figure; Talk presented at LATTICE96(algorithms

Heavy-Heavy-Light-Light correlators in Liouville theory

We compute four-point functions of two heavy and two "perturbatively heavy" operators in the semiclassical limit of Liouville theory on the sphere. We obtain these "Heavy-Heavy-Light-Light" (HHLL) correlators to leading order in the conformal weights of the light insertions in two ways: (a) via a path integral approach, combining different methods to evaluate correlation functions from complex solutions for the Liouville field, and (b) via the conformal block expansion. This latter approach identifies an integral over the continuum of normalizable states and a sum over an infinite tower of lighter discrete states, whose contribution we extract by analytically continuing standard results to our HHLL setting. The sum over this tower reproduces the sum over those complex saddlepoints of the path integral that contribute to the correlator. Our path integral computations reveal that when the two light operators are inserted at equal time in radial quantization, the leading-order HHLL correlator is independent of their separation, and more generally that at this order there is no short-distance singularity as the two light operators approach each other. The conformal block expansion likewise shows that in the discrete sum short-distance singularities are indeed absent for all intermediate states that contribute. In particular, the Virasoro vacuum block, which would have been singular at short distances, is not exchanged. The separation-independence of equal-time correlators is due to cancelations between the discrete contributions. These features lead to a Lorentzian singularity that, in conformal theories with anti-de Sitter (AdS) duals, would be associated to locality below the AdS scale.Comment: 40 pages, 1 figure; v2: clarifications added, minor typos corrected, published versio

One-flavour QCD at finite temperature

We present results, for heavy to moderate quark masses, of a study of thermodynamic properties of 1-flavour QCD, using the multiboson algorithm. Finite-size scaling behaviour is studied on lattices of size $8^3\times 4$, $12^3\times 4$ and $16^3\times 4$. It is shown that, for heavy quarks, the peak of the Polyakov loop susceptibility grows linearly with the spatial volume, indicating a first order phase transition. The deconfinement ratio and the distribution of the norm of the Polyakov loop corroborate this result. For moderately heavy quarks the first-order transition weakens and becomes a crossover. We estimate the end point of the first-order phase transition to occur at a quark mass of about 1.6 GeV.Comment: 3 pages, 3 PostScript figures; Talk presented at LAT9

Borges en Italia, Italia en Borges

Fil: Galli de Ortega, Gloria. Universidad Nacional de Cuyo. Facultad de Filosofía y Letra

El coraje del petirrojo

En la nueva narrativa italiana Maurizio Maggiani -nacido en 1951- se ha ganado un espacio propio y con paso firme está entrando en la escena literaria europea. Màuri,Màuri (1989), Vi ho già tutti sognato una volta (1990), Felice alla guerra (1992),I/ coraggio del pettirosso (1995), La regina disadorna (1998); las cinco obras con las que ya demuestra un talento excepcional para contar historias y una capacidad de escritura en crecimiento. Un escritor joven pero de oficio seguro. En esta ocasión nos ocuparemos de // coraggio del pettirosso1, un libro de difícil lectura, con una configuración muy trabajada incluso a nivel tipográfico. Extraña es la historia, apoyada en un imaginario que no remite a un modelo cultural unitario. Transcurre en Alejandría de Egipto, en los barrios de la ciudad vieja, en las playas arenosas del puerto de hoy, en el puerto sepultado de la antigua Alejandría y en el desierto. Recrea de manera fascinante la vida de los italianos que emigraron a ese país, las luchas de los libertarios de ayer y de hoy y el mundo de la Inquisición y la historia del pueblo apuano y de los valdenses. Todo contado por un escritor bien encaminado para recuperar el eco de la memoria, de sólida cultura, de fina sensibilidad.Fil: Galli de Ortega, Gloria. Universidad Nacional de Cuyo. Facultad de Filosofía y Letra