Compton Thick AGN in the 70 Month Swift-BAT All-Sky Hard X-ray Survey: a Bayesian approach

The 70-month Swift/BAT catalogue provides a sensitive view of the extragalactic X-ray sky at hard energies (>10 keV) containing about 800 Active Galactic Nuclei. We explore its content in heavily obscured, Compton-thick AGN by combining the BAT (14-195 keV) with the lower energy XRT (0.3-10 keV) data. We apply a Bayesian methodology using Markov chains to estimate the exact probability distribution of the column density for each source. We find 53 possible Compton-thick sources (with probability 3 to 100%) translating to a ~7% fraction of the AGN in our sample. We derive the first parametric luminosity function of Compton-thick AGN. The unabsorbed luminosity function can be represented by a double power-law with a break at $L_{\star} 2 \times 10^{42}$ $\rm ergs~s^{-1}$ in the 20-40 keV band.Comment: 13 pages, 9 figure

A deep X-ray observation of M82 with XMM-Newton

We report on the analysis of a deep (100 ks) observation of the starburst galaxy M82 with the EPIC and RGS instruments on board the X-ray telescope XMM-Newton. The broad-band (0.5-10 keV) emission is due to at least three spectral components: i) continuum emission from point sources; ii) thermal plasma emission from hot gas; iii) charge exchange emission from neutral metals (Mg and Si). The plasma emission has a double-peaked differential emission measure, with the peaks at ~0.5 keV and ~7 keV. Spatially resolved spectroscopy has shown that the chemical absolute abundances are not uniformly distributed in the outflow, but are larger in the outskirts and smaller close to the galaxy centre. The abundance ratios also show spatial variations. The X-ray derived Oxygen abundance is lower than that measured in the atmospheres of red supergiant stars, leading to the hypothesis that a significant fraction of Oxygen ions have already cooled off and no longer emit at energies > ~0.5 keV.Comment: Accepted for publication in MNRAS. 20 pages, 15 figures, LaTeX2

The 2-10 keV luminosity as a Star Formation Rate indicator

Radio and far infrared luminosities of star-forming galaxies follow a tight linear relation. Making use of ASCA and BeppoSAX observations of a well-defined sample of nearby star-forming galaxies, we argue that tight linear relations hold between the X-ray, radio and far infrared luminosities. The effect of intrinsic absorption is investigated taking NGC3256 as a test case. It is suggested that the hard X-ray emission is directly related to the Star Formation Rate. Star formation processes may also account for most of the 2-10 keV emission from LLAGNs of lower X-ray luminosities (for the same FIR and radio luminosity). Deep Chandra observations of a sample of radio-selected star-forming galaxies in the Hubble Deep Field North show that the same relation holds also at high (0.2< z< 1.3) redshift. The X-ray/radio relations also allow a derivation of X-ray number counts up to very faint fluxes from the radio Log N-Log S, which is consistent with current limits and models. Thus the contribution of star-forming galaxies to the X-ray background can be estimated

Access to Healthcare as a New Commons: Telemedicine as a Strategy for Providing Value-Based Healthcare Services in Rural Areas

Commons is a general term that refers to a resource shared by a group of people. Over the years, scholars have identified two generations of commons. The first generation of commons was about sharing of physical things; the second one is about intangible commons pool resources such as science and culture. These generally can be recognized as "rights" (Hess 2008). Among the various New Commons sectors there is medical and health. In the perspective of guaranteeing the right of Health, the ―Access to Healthcare‖ could be considered as a New Commons provided by worldwide National Healthcare Systems (NHS), However, healthcare sector is characterized by plenty of stakeholders with myriad, often, conflicting goals. The value-based approach (Porte, 2010) attempts to introduce a new universal language in healthcare management around the value for the patient that reconcile all stakeholders‘ interests. The goal of this approach is to improve the outcome and increase the number of treatments. This aim is very difficult to be enriched for rural residents; when patients live in remote areas, providing them with valuable medical care can be considered a hard challenge for the NHS, which has to be addressed also by the employment of new healthcare strategies and technologies. Defined as "a new healthcare delivery process provided when patient and professional are not physically in the same place" (Italian Ministry of Health, 2014), telemedicine could be seen as an answer to this challenge. Accordingly, this study aims at discovering if telemedicine employment can be effectively considered as a successful strategy to improve healthcare in location far from specialized hospital, enhancing the New Commons ―Access to care‖. A statistical-based narrative review of the literature was conducted in the field of telemedicine, with the aim to understand which experiences of telemedicine applications have got successful results as support of healthcare delivering in rural locations. With regards to rural and remote areas, several Authors recognized telemedicine-based strategies as a method to facilitate the access to healthcare in different medical disciplines. In particular, many studies highlight that telemedicine improves patient care by increasing the capacity of the rural clinician to manage patient locally, minimizing time away to support networks and reducing unnecessary transfers. Telemedicine could also be considered a cost-effective method whose outcomes remain similar (if not better) in quality to ―staffed‖ services, whose infrastructural costs could be easily paid-back

Finite mixtures of quantile and M-quantile regression models

In this paper we define a finite mixture of quan- tile and M-quantile regression models for heterogeneous and /or for dependent/clustered data. Components of the finite mixture represent clusters of individuals with homogeneous values of model parameters. For its flexibility and ease of estimation, the proposed approaches can be extended to ran- dom coefficients with a higher dimension than the simple random intercept case. Estimation of model parameters is obtained through maximum likelihood, by implementing an EM-type algorithm. The standard error estimates for model parameters are obtained using the inverse of the observed information matrix, derived through the Oakes (J R Stat Soc Ser B 61:479–482, 1999) formula in the M-quantile setting, and through nonparametric bootstrap in the quantile case. We present a large scale simulation study to analyse the practical behaviour of the proposed model and to evaluate the empiri- cal performance of the proposed standard error estimates for model parameters. We considered a variety of empirical set- tings in both the random intercept and the random coefficient case. The proposed modelling approaches are also applied to two well-known datasets which give further insights on their empirical behaviour

X-ray properties of radio-selected star forming galaxies in the Chandra-COSMOS survey

X-ray surveys contain sizable numbers of star forming galaxies, beyond the AGN which usually make the majority of detections. Many methods to separate the two populations are used in the literature, based on X-ray and multiwavelength properties. We aim at a detailed test of the classification schemes and to study the X-ray properties of the resulting samples. We build on a sample of galaxies selected at 1.4 GHz in the VLA-COSMOS survey, classified by Smolcic et al. (2008) according to their optical colours and observed with Chandra. A similarly selected control sample of AGN is also used for comparison. We review some X-ray based classification criteria and check how they affect the sample composition. The efficiency of the classification scheme devised by Smolcic et al. (2008) is such that ~30% of composite/misclassified objects are expected because of the higher X-ray brightness of AGN with respect to galaxies. The latter fraction is actually 50% in the X-ray detected sources, while it is expected to be much lower among X-ray undetected sources. Indeed, the analysis of the stacked spectrum of undetected sources shows, consistently, strongly different properties between the AGN and galaxy samples. X-ray based selection criteria are then used to refine both samples. The radio/X-ray luminosity correlation for star forming galaxies is found to hold with the same X-ray/radio ratio valid for nearby galaxies. Some evolution of the ratio may be possible for sources at high redshift or high luminosity, tough it is likely explained by a bias arising from the radio selection. Finally, we discuss the X-ray number counts of star forming galaxies from the VLA- and C-COSMOS surveys according to different selection criteria, and compare them to the similar determination from the Chandra Deep Fields. The classification scheme proposed here may find application in future works and surveys.Comment: 15 pages, 7 figures, 3 table

Westward drift of the lithosphere: Not a result of rotational drag

It is shown that any non-zero torque resulting from differences in angular velocity between individual shells in the Earth would be an extremely short transient phenomenon as a consequence of the viscosity of the asthenosphere. Consequently, it cannot be a factor in the origin of the toroidal velocity field of degree one ('westward drift') of the lithosphere

Методика и методология социолингвистических исследований в условиях билингвизма и диглоссии

Lithospheric-scale analogue models are used to analyse the parameters controlling the typical evolution of deformation during continental narrow rifting, characterized by early activation of large boundary faults and basin subsidence, followed by localization of tectonic activity in internal faults at the rift axis. Integration of current and previous experiments shows that the evolution of deformation, in particular the amount of extension needed for the abandonment of boundary faults and migration of deformation to in-rift faults, is dependent on at least five boundary conditions: (i) thickness of brittle layers (including syn-rift sediments); (ii) thickness of ductile layers; (iii) extension rate; (iv) width of the weak zone localizing extension; and (v) rift obliquity with respect to the extension direction. An increase in the amount of extension corresponding to the inward migration of faulting (i.e., a longer phase of slip on boundary faults) is observed for (a) an increase in the thickness of both brittle and ductile crustal layers and syn-rift sediment accumulation, (b) a decrease in extension rate and width of the weak zone, and (c) a decrease in rift obliquity. A unified account of these correlations is presented, based on the hypothesis that fault migration occurs when boundary faults can no longer accommodate the imposed bulk extension, leading to time-space variations of internal strain and strain rate (and consequently stress) in the ductile layers which overcome the total resistance of brittle layers to thoroughgoing faulting

A probabilistic approach to risk assessment of slow slope movements

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