4,476 research outputs found

    A multidimensional approach to the measurement of poverty

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    By using fuzzy set theory a cross country multidimensional analysis of poverty is performed on the basis of ECHP data. A set of composite indicators is contructed in order to analyse different dimensions of poverty. For each indicator is calculated an unidimensional poverty ratio, thus allowing a comparison among countries and indicators on the dimensions of poverty. Finally, for each country a multidimensional poverty ratio is obtained.

    Imprints of a high velocity wind on the soft x-ray spectrum of PG 1211+143

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    An extended XMM-Newton observation of the luminous narrow line Seyfert galaxy PG 1211+143 in 2014 has revealed a more complex high velocity wind, with components distinguished in velocity, ionization level, and column density. Here we report soft x-ray emission and absorption features from the ionized outflow, finding counterparts of both high velocity components, v ~ 0.129c and v ~ 0.066c, recently identified in the highly ionized Fe K absorption spectrum. The lower ionization of the co-moving soft x-ray absorbers imply a distribution of higher density clouds embedded in the main outflow, while much higher column densities for the same flow component in the hard x-ray spectra suggest differing sight lines to the continuum x-ray source.Comment: 8 pages, 5 figures, 4 tables; Accepted for publication in MNRA

    An Inkjet Printed Chipless RFID Sensor for Wireless Humidity Monitoring

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    A novel chipless RFID humidity sensor based on a finite Artificial Impedance Surface (AIS) is presented. The unit cell of the AIS is composed of three concentric loops thus obtaining three deep and high Q nulls in the electromagnetic response of the tag. The wireless sensor is fabricated using low-cost inkjet printing technology on a thin sheet of commercial coated paper. The patterned surface is placed on a metal backed cardboard layer. The relative humidity information is encoded in the frequency shift of the resonance peaks. Varying the relative humidity level from 50% to 90%, the frequency shift has proven to be up to 270MHz. The position of the resonance peaks has been correlated to the relative humidity level of the environment on the basis of a high number of measurements performed in a climatic chamber, specifically designed for RF measurements of the sensor. A very low error probability of the proposed sensor is demonstrated when the device is used with a 10% RH humidity level discrimination

    Latent class models in financial data analysis

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    This paper deals with optimal international portfolio choice by developing a latent class approach based on the distinction between international and non-international investors. On the basis of micro data, we analyze the effects of many social, demographic, economic and financial characteristics on the probability to be an international investor. Traditional measures of equity home bias do not allow for the existence of international investment rationing operators. On the contrary, by resorting to latent class analysis it is possible to detect the unobservable distinction between international investors and investors who are precluded from operating into international financial markets and, therefore, to evaluate the role of these unobservable constraints on equity home bias

    Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in PDS 456

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    High resolution soft X-ray spectroscopy of the prototype accretion disk wind quasar, PDS 456, is presented. Here, the XMM-Newton RGS spectra are analyzed from the large 2013-2014 XMM-Newton campaign, consisting of 5 observations of approximately 100 ks in length. During the last observation (hereafter OBS. E), the quasar is at a minimum flux level and broad absorption line profiles are revealed in the soft X-ray band, with typical velocity widths of σv10,000\sigma_{\rm v}\sim 10,000 km s1^{-1}. During a period of higher flux in the 3rd and 4th observations (OBS. C and D, respectively), a very broad absorption trough is also present above 1 keV. From fitting the absorption lines with models of photoionized absorption spectra, the inferred outflow velocities lie in the range 0.10.2c\sim 0.1-0.2c. The absorption lines likely originate from He and H-like neon and L-shell iron at these energies. Comparison with earlier archival data of PDS 456 also reveals similar absorption structure near 1 keV in a 40 ks observation in 2001, and generally the absorption lines appear most apparent when the spectrum is more absorbed overall. The presence of the soft X-ray broad absorption lines is also independently confirmed from an analysis of the XMM-Newton EPIC spectra below 2 keV. We suggest that the soft X-ray absorption profiles could be associated with a lower ionization and possibly clumpy phase of the accretion disk wind, where the latter is known to be present in this quasar from its well studied iron K absorption profile and where the wind velocity reaches a typical value of 0.3cc.Comment: 44 pages, including 13 figures, accepted for publication in The Astrophysical Journa

    Short term X-ray spectral variability of the quasar PDS 456 observed in a low flux state

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    We present an analysis of the 2013 Suzaku campaign on the nearby luminous quasar PDS 456, covering a total duration of ~1 Ms and a net exposure of 455 ks. During these observations, the X-ray flux was suppressed by a factor of >10 in the soft X-ray band when compared to other epochs. We investigated the broadband continuum by constructing a spectral energy distribution, making use of the optical/UV photometry and hard X-ray spectra from the later XMM-Newton/NuSTAR campaign in 2014. The high energy part of this low flux state cannot be accounted for by self-consistent accretion disc and corona models without attenuation by absorbing gas, which partially covers a substantial fraction of the line of sight towards the X-ray source. Two absorption layers are required, of column density log(NH,low/cm2)=22.3±0.1\log (N_{\rm{H,low}}/{\rm cm^{-2}})=22.3\pm0.1 and log(NH,high/cm2)=23.2±0.1\log (N_{\rm{H,high}}/{\rm cm^{-2}})=23.2\pm0.1, with average covering factors of ~80% (with typical 5% variations) and 60% (±\pm10-15%), respectively. In these observations PDS 456 displays significant short term X-ray spectral variability, on timescales of ~100 ks, which can be accounted for by variable covering of the absorbing gas. The partial covering absorber prefers an outflow velocity of vpc=0.250.05+0.01cv_{\rm pc} = 0.25^{+0.01}_{-0.05}c at the >99.9% confidence level over the case where vpc=0v_{\rm pc}=0. This is consistent with the velocity of the highly ionised outflow responsible for the blueshifted iron K absorption profile. We therefore suggest that the partial covering clouds could be the denser, or clumpy part of an inhomogeneous accretion disc wind. Finally we estimate the size-scale of the X-ray source from its variability. The radial extent of the X-ray emitter is found to be of the order ~15-20 RgR_{\rm g}, although the hard X-ray (>2 keV) emission may originate from a more compact or patchy corona of hot electrons, which is ~6-8 RgR_{\rm g} in size.Comment: 38 pages, 13 figures, accepted for publication in MNRA
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