2,712 research outputs found

    Extended sources in the XMM-Newton slew survey

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    The low background, good spatial resolution and great sensitivity of the EPIC-pn camera on XMM-Newton give useful limits for the detection of extended sources even during the short exposures made during slewing maneouvers. In this paper we attempt to illustrate the potential of the XMM-Newton slew survey as a tool for analysing flux-limited samples of clusters of galaxies and other sources of spatially extended X-ray emission.Comment: 2 pages, 4 figures, to appear in the proceedings of "The X-ray Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200

    Liquidity provision: lessons from a natural experiment

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    We study the reaction of more than 60,000 firms to a large unexpected liquidity shock in Spain during a severe recessionary period. The Spanish central government repaid in 2012 almost 30bn euros (approximately 3% of GDP) of arrears that Territorial Administrations had been accumulating for years. We assess the economic impact of the plan using two alternative estimation strategies. First, we use a differences-in-differences (DID) approach that exploits heterogeneity in the size of the liquidity received by firms. Second, we take advantage of the plan's plausibly exogenous disbursement implementation and run a DID procedure using as control group some firms that were paid a year later. Overall, we find that a governmental liquidity injection during a recession increases corporate investment significantly: on average firms use 4% of cash transfers for investment. This effect is stronger for firms with lower default risk and higher investment opportunities. Firms with higher default risk are more prone to repay financial debt. On average, firms use 8% of cash transfers to repay financial debt.Vicente also acknowledges nancial assistance from the International Mobility Program UC3M

    The XMM-Newton Slew Survey: towards the XMMSL1 catalogue

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    The XMM-Newton satellite is the most sensitive X-ray observatory flown to date due to the great collecting area of its mirrors coupled with the high quantum efficiency of the EPIC detectors. It performs slewing manoeuvers between observation targets tracking almost circular orbits through the ecliptic poles due to the Sun constraint. Slews are made with the EPIC cameras open and the other instruments closed, operating with the observing mode set to the one of the previous pointed observation and the medium filter in place. Slew observations from the EPIC-pn camera in FF, eFF and LW modes provide data, resulting in a maximum of 15 seconds of on-source time. These data can be used to give a uniform survey of the X-ray sky, at great sensitivity in the hard band compared with other X-ray all-sky surveys.Comment: 2 pages, 2 figures, to appear in the proceedings of "The X-ray Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200

    How does easing liquidity constraints affect aggregate employment?

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    We measure the impact of removing liquidity constraints on aggregate employment by focusing on a sudden and unexpected large liquidity injection to Spanish firms in early 2012, when the Spanish central government paid all invoices of firms to regional and municipal governments that were in arrears. We identify the effect on employment from the cross-sectional variation in the size of the liquidity injection received by Spanish municipalities. Our preliminary finding sindicate that labor market responses can be detected both in the municipality where the liquidity injection occurs and in the municipality where firms are headquartered. We find evidence that the effect on unemployment is stronger where the liquidity injection originates whereas the effect on employment is stronger where the firms are located

    Single-molecule kinetic energy of condensed normal deuterium

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    8 págs.; 9 figs.; 1 tab.Inelastic scattering of 300-meV neutrons allows the study of the liquid (T=20 and 30 K, saturated vapor pressure) and solid (T=4.2 K, saturated vapor pressure) phases of the normal deuterium mixture (2/3 o-D2+1/3 p -D2) in the region of momentum transfer where a single-molecule response is expected. The spectra are analyzed within the impulse approximation and assuming Gaussian momentum distributions for the translation of the molecules. For the solid, the estimated value of the single-molecule average kinetic energy does not compare unfavorably with those obtained scaling experimental results in parahydrogen solids. In the liquid state, substantial departures seem to exist from the classical liquid behavior, even if up to second-order quantum corrections are taken into account. ©1996 American Physical SocietyThis research has been made possible in part by the Spanish DGICYT through Grant No. PB92-0015.Peer Reviewe

    Actualización en radiología dental: Radiología convencional Vs digital

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    Desde su incorporación a la práctica odontológica la radiología digital ha experimentado un importante desarrollo. El continuo avance de las tecnologías en las que se sustenta ha dotado a estos sistemas de interesantes prestaciones que pueden facilitar el diagnóstico y manejo de imágenes radiográficas. Con estos avances la radiología digital ha despertado un interés creciente entre los profesionales de la odontología, especialmente durante los últimos años, en los que ha aumentado notoriamente tanto la cantidad de sistemas comercializados como el número de odontólogos que han decidido sustituir la radiología convencional por un sistema digital en sus clínicas. En esta revisión de la literatura se tratará de ofrecer una visión actualizada de los distintos sistemas disponibles en la actualidad, así como una comparativa entre ellos basada en estudios publicados recientemente. Since its appearance in dentistry, digital radiology has experienced a notorious development. A constant advance in the corresponding technologies has enhanced these digital systems with interesting features which may facilitate radiological diagnosis and image management. Due to these advances digital radiology has elicited a growing interest in dentistry. Specially during the last years there has been an increase both in the amount of available systems and in the number of dentists who have incorporated a digital system in their offices. This literature review aims to offer an updated view of the available systems and a comparison of them based in recent studies
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