The Indirect Search for Dark Matter from the centre of the Galaxy with the Fermi LAT

Dark matter (DM) constitutes around a 25% of the Universe, while baryons only a 4%. DM can be reasonably assumed to be made of particles, and many theories (Super-symmetry, Universal Extra Dimensions, etc.) predict Weakly Interacting Massive Particles (WIMPs) as natural DM candidates at the weak scale. Self-annihilation (or decay) of WIMPs might produce secondary gamma-rays, via hadronization or as final state radiation. Since its launch in the 2008, the Large Area Telescope on-board of the Fermi gamma-ray Space Telescope has detected the largest amount of gamma-rays to date, in the 20MeV 300GeV energy range, allowing to perform a very sensitive indirect experimental search for DM (by means of high-energy gamma-rays). DM forms large gravitationally bounded structures, the halos, which can host entire galaxies, such as the Milky Way. The DM distribution in the central part of the halos is not experimentally know, despite a very large density enhancement might be present. As secondary gamma rays production is very sensitive to WIMP density, a very effective search can be performed from the regions where the largest density is expected. Therefore the information provided by the DM halo N-body simulations are crucial. The largest gamma-ray signal from DM annihilation is expected from the centre of the Galaxy. In the same region a large gamma-ray background is produced by bright discrete sources and the cosmic-rays interacting with the interstellar gas and the photons fields. Here we report an update of the indirect search for DM from the Galactic Center (GC).Comment: 6 pages, 2 figures. Invited talk presented at the Workshop "SciNeGHE 2010", September 8-10, 2010, Trieste, Italy. To appear in Il Nuovo Cimento C - Colloquia on physic

La transformación de los procesos de gestión de la información en la Universidad Católica de Santa Fe a partir de la incorporación de las nuevas tecnologías

La gestión de la información y los procesos de comunicación institucional constituyen uno de los pilares fundamentales en el desenvolvimiento de la vida de las universidades. A partir de la década del 80, estos procesos sufrieron importantes cambios en todo el mundo debido a la incorporación de las nuevas tecnologías. A través del siguiente trabajo comunicaremos los procesos de gestión de la información, a partir de la incorporación de las nuevas herramientas que ofrecen las tecnologías. Presentando nuestra experiencia desde la Universidad Católica de Santa Fe, las fortalezas y debilidades del modelo de gestión en vigencia. Y proponiendo un diseño de gestión de estos procesos que contemple un uso adecuado de, lo que se considera, las principales herramientas del cambio: correo electrónico, Web y mensajería

Gestión estratégica de las estructuras académicas y administrativas, de la Universidad Católica de Santa Fe, para su adecuación al proceso de evaluación y acreditación

A partir de los años 80 comenzó a imponerse la necesidad de acordar criterios comunes respecto a los umbrales de la calidad educativa impartida por instituciones universitarias de todo el mundo. Nuestro país no quedó al margen de estas transformaciones, y comenzó el proceso con la promulgación de la legislación que fijara los criterios para la adecuación de la educación a los nuevos requerimientos de calidad. La sanción de la Ley N°24521 impulsó este cambio por el cual las universidades debieron adecuar sus estructuras académicas y administrativas para alcanzar los estándares impuestos por la acreditación. A través del presente trabajo comunicaremos la experiencia de la Universidad Católica de Santa Fe en el marco de este proceso

Quantum Zeno effect and the detection of gravitomagnetism

In this work we introduce two experimental proposals that could shed some light upon the inertial properties of intrinsic spin. In particular we will analyze the role that the gravitomagnetic field of the Earth could have on a quantum system with spin 1/2. We will deduce the expression for Rabi transitions, which depend, explicitly, on the coupling between the spin of the quantum system and the gravitomagnetic field of the Earth. Afterwards, the continuous measurement of the energy of the spin 1/2 system is considered, and an expression for the emerging quantum Zeno effect is obtained. Thus, it will be proved that gravitomagnetism, in connection with spin 1/2 systems, could induce not only Rabi transitions but also a quantum Zeno effect.Comment: Essay awarded with an ``honorable mention'' in the Annual Essay Competition of the Gravity Research Foundation for the year 2000, four new references, discussion enlarged, 9 pages. Accepted in International Journal of Modern Physics

The face-space duality hypothesis: a computational model

Valentine's face-space suggests that faces are represented in a psychological multidimensional space according to their perceived properties. However, the proposed framework was initially designed as an account of invariant facial features only, and explanations for dynamic features representation were neglected. In this paper we propose, develop and evaluate a computational model for a twofold structure of the face-space, able to unify both identity and expression representations in a single implemented model. To capture both invariant and dynamic facial features we introduce the face-space duality hypothesis and subsequently validate it through a mathematical presentation using a general approach to dimensionality reduction. Two experiments with real facial images show that the proposed face-space: (1) supports both identity and expression recognition, and (2) has a twofold structure anticipated by our formal argument

Health Facilities Safety in Natural Disasters: Experiences and Challenges from South East Europe

The United Nations named 2010 as a year of natural disasters, and launched a worldwide campaign to improve the safety of schools and hospitals from natural disasters. In the region of South East Europe, Croatia and Serbia have suffered the greatest impacts of natural disasters on their communities and health facilities. In this paper the disaster management approaches of the two countries are compared, with a special emphasis on the existing technological and legislative systems for safety and protection of health facilities and people. Strategic measures that should be taken in future to provide better safety for health facilities and populations, based on the best practices and positive experiences in other countries are recommended. Due to the expected consequences of global climate change in the region and the increased different environmental risks both countries need to refine their disaster preparedness strategies. Also, in the South East Europe, the effects of a natural disaster are amplified in the health sector due to its critical medical infrastructure. Therefore, the principles of environmental security should be implemented in public health policies in the described region, along with principles of disaster management through regional collaborations

Acceleration disturbances and requirements for ASTROD I

ASTRODynamical Space Test of Relativity using Optical Devices I (ASTROD I) mainly aims at testing relativistic gravity and measuring the solar-system parameters with high precision, by carrying out laser ranging between a spacecraft in a solar orbit and ground stations. In order to achieve these goals, the magnitude of the total acceleration disturbance of the proof mass has to be less than 10−13 m s−2 Hz−1/2 at 0.1 m Hz. In this paper, we give a preliminary overview of the sources and magnitude of acceleration disturbances that could arise in the ASTROD I proof mass. Based on the estimates of the acceleration disturbances and by assuming a simple controlloop model, we infer requirements for ASTROD I. Our estimates show that most of the requirements for ASTROD I can be relaxed in comparison with Laser Interferometer Space Antenna (LISA).Comment: 19 pages, two figures, accepted for publication by Class. Quantum Grav. (at press

On-ground tests of LISA PathFinder thermal diagnostics system

Thermal conditions in the LTP, the LISA Technology Package, are required to be very stable, and in such environment precision temperature measurements are also required for various diagnostics objectives. A sensitive temperature gauging system for the LTP is being developed at IEEC, which includes a set of thermistors and associated electronics. In this paper we discuss the derived requirements applying to the temperature sensing system, and address the problem of how to create in the laboratory a thermally quiet environment, suitable to perform meaningful on-ground tests of the system. The concept is a two layer spherical body, with a central aluminium core for sensor implantation surrounded by a layer of polyurethane. We construct the insulator transfer function, which relates the temperature at the core with the laboratory ambient temperature, and evaluate the losses caused by heat leakage through connecting wires. The results of the analysis indicate that, in spite of the very demanding stability conditions, a sphere of outer diameter of the order one metre is sufficient. We provide experimental evidence confirming the model predictions.Comment: 18 pages, 5 figures, LaTeX2e (compile with pdflatex), sumbitted to CQG. This paper is a significant extension of gr-qc/060109