6,803 research outputs found

    The Bologna Complete Sample of Nearby Radio Sources

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    We present a new, complete, sample of 95 radio sources selected from the B2 and 3CR catalogues, with z < 0.1. Since no selection effect on the core radio power, jet velocity, or source orientation is present, this sample is well suited for statistical studies. In this first paper we present the observational status of all sources on the parsec (mas) and kiloparsec (arcsec) scale; we give new parsec-scale data for 28 sources and discuss their parsec-scale properties. Combining these data with those in the literature, information on the parsec-scale morphology is available for a total of 53 radio sources with different radio power and kpc-scale morphology. We investigate their properties. We find a dramatically higher fraction of two-sided sources in comparison to previous flux limited VLBI surveys.Comment: 29 pages, 21 figures - ApJ in press (10 Jan 2005 issue

    Healthcare Insights: Evaluating the Access to the Italian Healthcare System

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    The Italian health system is organised on a regional basis and services are provided by both public and private operators, affecting the planning of services, access to services by citizens and their health rights. The creation of an observatory monitoring the methods and times of access to healthcare services has been pursued. The preliminary phase of the project is presented, which will lead to the comparison of the data obtained from 2019, with an eye on the Covid-19 pandemic impact

    Obscuration and Origin of Nuclear X-ray emission in FR I Radio Galaxies

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    We present X-ray observations of the nuclear region of 25 Fanaroff-Riley I radio galaxies from the 3CRR and B2 catalogs, using data from the Chandra and XMM archives. We find the presence of a X-ray Central Compact Core (CCCX) in 13/25 sources, in 3/25 sources the detection of a CCCX is uncertain, while in the remaining 9/25 sources no CCCX is found. All the sources are embedded in a diffuse soft X-ray component, generally on kpc-scales, which is in agreement with the halo of the host galaxy and/or with the intracluster medium. The X-ray spectra of the cores are described by a power law with photon indices Gamma=1.1 - 2.6. In 8 sources excess absorption over the Galactic value is detected, with rest-frame column densities N_H^z ~ 10^20 - 10^21 cm^-2; thus, we confirm the previous claim based on optical data that most FRI radio galaxies lack a standard optically-thick torus. We find significant correlations between the X-ray core luminosity and the radio and optical luminosities, suggesting that at least a fraction of the X-ray emission originates in a jet; however, the origin of the X-rays remains ambiguous. If the X-ray emission is entirely attributed to an isotropic, accretion-related component, we find very small Eddington ratios, L_bol/L_Edd ~ 10^-3 - 10^-8, and we calculate the radiative efficiency to be eta ~ 10^-2 - 10^-6, based on the Bondi accretion rates from the spatial analysis. This suggests that radiatively inefficient accretion flows are present in the cores of low-power radio galaxies.Comment: 20 pages, 7 figures, accepted for publication in The Astrophysical Journa

    Dengue fever complicated by liver dysfunction due to possible co-infection with hepatitis E in a returning traveller from Cuba

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    Dengue fever is a mosquito-borne infection that co-circulates with Chikungunya and Zika virus infection in many parts of the world. Dengue virus (DENV) is occasionally responsible for acute hepatitis and a few cases of acute hepatitis due to co-infection with DENV and hepatitis E virus have been described in India. A 37-year-old Cuban woman living in Italy was admitted to our hospital with a presumed arboviral infection upon her return to Italy short after a 15-day trip to her home-country to visit relatives. An acute infection due to DENV serotype 1 was initially diagnosed, following a clinical course characterized by signs of liver dysfunction that were possibly due to co-infection with hepatitis E virus

    Energy-Momentum Tensor of Field Fluctuations in Massive Chaotic Inflation

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    We study the renormalized energy-momentum tensor (EMT) of the inflaton fluctuations in rigid space-times during the slow-rollover regime for chaotic inflation with a mass term. We use dimensional regularization with adiabatic subtraction and introduce a novel analytic approximation for the inflaton fluctuations which is valid during the slow-rollover regime. Using this approximation we find a scale invariant spectrum for the inflaton fluctuations in a rigid space-time, and we confirm this result by numerical methods. The resulting renormalized EMT is covariantly conserved and agrees with the Allen-Folacci result in the de Sitter limit, when the expansion is exactly linearly exponential in time. We analytically show that the EMT tensor of the inflaton fluctuations grows initially in time, but saturates to the value H^2 H(0)^2, where H is the Hubble parameter and H(0) is its value when inflation has started. This result also implies that the quantum production of light scalar fields (with mass smaller or equal to the inflaton mass) in this model of chaotic inflation depends on the duration of inflation and is larger than the usual result extrapolated from the de Sitter result.Comment: revtex style, 24 pages, 6 eps figures Numerical checks added and moduli section improve

    Shaken, not blown: the gentle baryonic feedback of nearby starburst dwarf galaxies

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    Baryonic feedback is expected to play a key role in regulating the star formation of low-mass galaxies by producing galaxy-scale winds associated with mass-loading factors ÎČâ€‰âŁâˆŒâ€‰âŁ1 ⁣− ⁣50\beta\!\sim\!1\!-\!50. We have tested this prediction using a sample of 19 nearby systems with stellar masses 107 ⁣< ⁣M⋆/M⊙ ⁣< ⁣101010^7\!<\!M_\star/{\rm M}_{\odot}\!<\!10^{10}, mostly lying above the main sequence of star-forming galaxies. We used MUSE@VLT optical integral field spectroscopy to study the warm ionised gas kinematics of these galaxies via a detailed modelling of their Hα\alpha emission line. The ionised gas is characterised by irregular velocity fields, indicating the presence of non-circular motions of a few tens of km/s within galaxy discs, but with intrinsic velocity dispersion of 4040-6060 km/s that are only marginally larger than those measured in main-sequence galaxies. Galactic winds, defined as gas at velocities larger than the galaxy escape speed, encompass only a few percent of the observed fluxes. Mass outflow rates and loading factors are strongly dependent on M⋆M_\star, star formation rate (SFR), SFR surface density and specific SFR. For M⋆M_\star of 10810^8 M⊙_\odot we find ÎČ≃0.02\beta\simeq0.02, which is more than two orders of magnitude smaller than the values predicted by theoretical models of galaxy evolution. In our galaxy sample, baryonic feedback stimulates a gentle gas cycle rather than causing a large-scale blow out.Comment: 20 pages, 11 figures, submitted to A&A. Comments are welcome

    Augmented reality meeting table: a novel multi-user interface for architectural design

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    Immersive virtual environments have received widespread attention as providing possible replacements for the media and systems that designers traditionally use, as well as, more generally, in providing support for collaborative work. Relatively little attention has been given to date however to the problem of how to merge immersive virtual environments into real world work settings, and so to add to the media at the disposal of the designer and the design team, rather than to replace it. In this paper we report on a research project in which optical see-through augmented reality displays have been developed together with prototype decision support software for architectural and urban design. We suggest that a critical characteristic of multi user augmented reality is its ability to generate visualisations from a first person perspective in which the scale of rendition of the design model follows many of the conventions that designers are used to. Different scales of model appear to allow designers to focus on different aspects of the design under consideration. Augmenting the scene with simulations of pedestrian movement appears to assist both in scale recognition, and in moving from a first person to a third person understanding of the design. This research project is funded by the European Commission IST program (IST-2000-28559)

    Slow-roll, acceleration, the Big Rip and WKB approximation in NLS-type formulation of scalar field cosmology

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    Aspects of non-linear Schr\"{o}dinger-type (NLS) formulation of scalar (phantom) field cosmology on slow-roll, acceleration, WKB approximation and Big Rip singularity are presented. Slow-roll parameters for the curvature and barotropic density terms are introduced. We reexpress all slow-roll parameters, slow-roll conditions and acceleration condition in NLS form. WKB approximation in the NLS formulation is also discussed when simplifying to linear case. Most of the Schr\"{o}dinger potentials in NLS formulation are very slowly-varying, hence WKB approximation is valid in the ranges. In the NLS form of Big Rip singularity, two quantities are infinity in stead of three. We also found that approaching the Big Rip, weff→−1+2/3qw_{\rm eff}\to -1 + {2}/{3q}, (q<0)(q<0) which is the same as effective phantom equation of state in the flat case.Comment: [7 pages, no figure, more reference added, accepted by JCAP
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