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In the era of huge astronomical surveys, machine learning offers promising solutions for the efficient estimation of galaxy properties. The traditional, `supervised' paradigm for the application of machine learning involves training a model on labelled data, and using this model to predict the labels of previously unlabelled data. The semi-supervised `pseudo-labelling' technique offers an alternative paradigm, allowing the model training algorithm to learn from both labelled data and as-yet unlabelled data. We test the pseudo-labelling method on the problems of estimating redshift, stellar mass, and star formation rate, using COSMOS2015 broad band photometry and one of several publicly available machine learning algorithms, and we obtain significant improvements compared to purely supervised learning. We find that the gradient-boosting tree methods CatBoost, XGBoost, and LightGBM benefit the most, with reductions of up to ~15% in metrics of absolute error. We also find similar improvements in the photometric redshift catastrophic outlier fraction. We argue that the pseudo-labellng technique will be useful for the estimation of redshift and physical properties of galaxies in upcoming large imaging surveys such as Euclid and LSST, which will provide photometric data for billions of sources., 10 pages, 6 figures, accepted for publication in MNRAS

BackgroundThe COVID-19 pandemic that emerged in Wuhan, China at the end of 2019, spread rapidly around the world with almost 600 million cases and 6.3 million deaths today. The most affected were health workers with at least three times the risk of contracting the disease than the general community. Most studies on seroprevalence in health workers focus on hospital care establishments and what happens in Primary Health Care (PHC) has not been investigated with the same intensity.Objectivesto determine the prevalence and know the variation of antibody titers for SARS-CoV-2 in serial samples of primary healthcare personnel from the commune of La Pintana.Methodan analytical observational study with a cross-sectional and a longitudinal component, carried out from November 2020 to June 2021. The first component consisted of an IgG antibody seroprevalence study performed at baseline (time 0) in volunteer of a universe of 900 workers. The longitudinal component considered the monitoring of IgG antibodies in those who presented a positive result at baseline and the analysis of neutralizing antibodies in a random sub-sample of 50% of them. Additionally, sociodemographic and clinical information was collected via a questionnaire. Univariate, bivariate, and longitudinal analyses were performed to evaluate differences in antibodies. The study was approved by the Universidad del Desarrollo’s Scientific Ethics Committee.Results463 primary healthcare workers participated, mostly women and with a median of 38 years; doctors and nurses represented 9.5% each and 14.7% had a history of COVID-19. The seroprevalence at baseline was 22.3% and was associated with younger age, being a doctor and having been in close contact of a case. IgG titers increased with the vaccine, but decreased over time. At the 6-month follow-up, 76% had neutralizing antibodies. Those belonging to indigenous peoples had higher IgG levels and higher rates of neutralizing antibodies.ConclusionHealthcare workers were highly affected by COVID-19, and the medical profession and younger age were factors associated with increased risk. Antibodies decrease over time, highlighting the importance of follow-up studies, as well as the importance of vaccination boosters in healthcare workers, especially those in PHC.FinancingThis project was funded by the Universidad del Desarrollo, COVID19-UDD 2020-21 Funds.

This end of degree project suggest a new control algorithm for a differential-drive mobile robot, based on a mathematical model that works only use robot local variables, the distance from the line and the deviation angle between the robot axis and the tangent of the path. A state-space feedback controller with a Luenberger observer, for the estimation of the deviation angle, had been designed from the model. This new control algorithm enhance the robot response in any given track. Moreover, allows the vehicle for backwards move under certain constrains, without the need of installing a new sensor in the back part. Being a initial point for the complete development of a control algorithm able to move in both directions. During the development of this project the controller was tested in several numerical simulations, this simulations are exposed and explained supporting the new solution. As well the code implemented in the robot, written in C, is annexed to the memory.

The first generation of E-ELT instruments will include an optical-infrared High Resolution Spectrograph, conventionally indicated as EELT-HIRES, which will be capable of providing unique breakthroughs in the fields of exoplanets, star and planet formation, physics and evolution of stars and galaxies, cosmology and fundamental physics. A 2-year long phase A study for EELT-HIRES has just started and will be performed by a consortium composed of institutes and organisations from Brazil, Chile, Denmark, France, Germany, Italy, Poland, Portugal, Spain, Sweden, Switzerland and United Kingdom. In this paper we describe the science goals and the preliminary technical concept for EELT-HIRES which will be developed during the phase A, as well as its planned development and consortium organisation during the study., 12 pages, in Ground-based and Airborne Instrumentation for Astronomy VI, 2016, Proc. SPIE 9908, 23

We present BeppoSAX observations of the southern S1 region in the European Large-Area Infrared Space Observatory (ISO) Survey (ELAIS). These observations cover an area of similar to1.7 deg(2) and reach an on-axis (similar to0.7 deg(2)) 2-10 keV (hard X-ray, or HX) sensitivity of similar to 10(-13) ergs s(-1) cm(-2). This is the first HX analysis of an ISOCAM survey. We detect nine sources with a signal-to-noise ratio SNRHX > 3, four additional sources with a 1.3-10 keV (total X-ray, or T) SNRT > 3, and two additional sources that seem to be associated with QSOs having SNRT > 2.9. The number densities of the SNRHX > 3 sources are consistent with the ASCA and BeppoSAX log N-log S functions. Six BeppoSAX sources have reliable ISOCAM 15 mum counterparts within similar to 60". All these ISOCAM sources have optical counterparts of R < 20 mag. Five of these sources have been previously optically classified, four as QSOs and one as a broad absorption line (BAL) QSO at z = 2.2. The remaining unclassified source has X-ray and photometric properties consistent with those of a nearby Seyfert galaxy. One further HX source has a 2.6 ISOCAM counterpart associated with a galaxy at z = 0.325. If this ISOCAM source is real, the HX/MIR properties suggest either an unusual QSO or a cD cluster galaxy. We have constructed MIR and HX spectral energy distributions to compute the expected HX/MIR ratios for these classes of objects up to z = 3.2 and assess the HX/MIR survey depth. The BAL QSO has an observed X-ray softness ratio and HX/MIR flux ratio similar to those of QSOs but different from those found for low-redshift BAL QSOs. This difference can be explained in terms of absorption, and it suggests that high-redshift BAL QSOs should be comparatively easy to detect in the HX band, allowing their true fraction in the high-redshift QSO population to be determined. The QSOs cover a wide redshift range (0.4

We report the discovery of the first hyperluminous infrared galaxy (HyLIG) in the course of the European Large Area ISO Survey (ELAIS). This object has been detected by ISO at 6.7, 15, and 90 microns, and is found to be a broad-line, radio-quiet quasar at a redshift: z = 1.099. From a detailed multi-component model fit of the spectral energy distribution, we derive a total infrared luminosity: L_IR (1-1000 microns) ~ 1.0 x 10E13 h_65^-2 L_sun (q_0 = 0.5), and discuss the possible existence of a starburst contributing to the far-IR output. Observations to date present no evidence for lens magnification. This galaxy is one of the very few HyLIGs with an X-ray detection. On the basis of its soft X-ray properties, we suggest that this broad-line object may be the face-on analogue of narrow-line, Seyfert-like HyLIGs., 6 pages, 4 figures; accepted for publication in MNRAS

In this work, we report the Photodetector Array Camera and Spectrometer (PACS) 100 μm/160 μm detections of a sample of 42 GALEX-selected and far-infrared (FIR)-detected Lyman break galaxies (LBGs) at z ~ 1 located in the Cosmic Evolution Survey (COSMOS) field and analyse their ultraviolet (UV) to FIR properties. The detection of these LBGs in the FIR indicates that they have a dust content high enough so that its emission can be directly detected. According to a spectral energy distribution (SED) fitting with stellar population templates to their UV-to-near-IR observed photometry, PACS-detected LBGs tend to be bigger (Reff ~ 4.1 kpc), more massive [log (M*/M⊙) ~ 10.7], dustier [Es(B - V) ~ 0.40], redder in the UV continuum (β ~ -0.60) and UV-brighter [log (LUV/L⊙) ~ 10.1] than PACSundetected LBGs. PACS-detected LBGs at z ~ 1 are mostly disc-like galaxies and are located over the green valley and red sequence of the colour-magnitude diagram of galaxies at their redshift. By using their UV and IR emission, we find that PACS-detected LBGs tend to be less dusty and have slightly higher total star formation rates (SFRs) than other PACS-detected UV-selected galaxies within the same redshift range. As a consequence of the selection effect due to the depth of the FIR observations employed, all our PACS-detected LBGs have total IR luminosities, LIR, higher than 1011 L⊙ and thus are luminous IR galaxies. However, none of the PACS-detected LBGs are in the ultra-luminous IR galaxy (ULIRG) regime, LIR =1012 L⊙, where the FIR observations are complete. The finding of ULIRGs-LBGs at higher redshifts (z ~ 3) suggests an evolution of the FIR emission of LBGs with cosmic time. In an IRX-β diagram, PACS-detected LBGs at z~1 tend to be located around the relation for local starburst similarly to other UV-selected PACS-detected galaxies at the same redshift. Consequently, the dust-correction factors obtained with theirUVcontinuum slope allowus to determine their total SFR, unlike at higher redshifts. However, the dust attenuation derived from UV to NIR SED fitting overestimates the total SFR for most of our PACS-detected LBGs in an age-dependent way: the overestimation factor is higher in younger galaxies. This is likely due to the typical degeneracy between dust attenuation and age in the SED fitting with synthetic templates and highlights the importance of the FIR measurements in the analysis of star-forming galaxies at intermediate redshifts. Generalitat Valenciana PROMETEO-2008/132 NASA Office of Space Science NNX09AF08G European Southern Observatory LP175.A-0839 Junta de Andalucía TIC-114, P08-TIC-03531 Ministerio de Economía y Competitividad AYA2011- 29517-C03-01, AYA2010-22111-C03-02, AYA2010-15169

We present the first determination of the 15 mum luminosity function of galaxies from the European Large Area ISO Survey (ELAIS) southern fields. We have adopted a new criterion to separate the quiescent, nonevolving and the starburst, evolving populations based on the ratio of mid-infrared to optical luminosity. Strong evolution is suggested by our data for the starburst galaxy population, while normal spiral galaxies are consistent with no evolution. The starburst population must evolve both in luminosity and in density with rates of the order L(z) proportional to (1 + z)(3.5) and rho(z) proportional to (1 + z)(3.8), respectively, up to z similar to 1. The evolutionary parameters of our model have been tested by comparing the model predictions with other observables, like source counts at all flux density levels (from 0.1 to 300 mJy) and redshift distributions and luminosity functions at high z (0.7 < z < 1.0 from Hubble Deep Field North [HDF-N] data). The agreement between our model predictions and the observed data is remarkably good. We use our data to estimate the star formation density of the universe up to z 0: 4, and we use the luminosity function model to predict the trend of the star formation history up to z = 1.

We present a multi-wavelength catalog (15 um, R, K-band, 1.4 GHz flux) plus spectroscopic identifications for 406 15 um sources detected in the ELAIS region S1, over the flux density range 0.5, Comment: Scheduled on AJ, Vol. 127/6, 2004 June. Table 2 (+ 15um sources coordinates) at http://www.fis.uniroma3.it/~ELAIS_S/lafrancabab.tab2.dat . Table 3 at http://www.fis.uniroma3.it/~ELAIS_S/lafrancabab.tab3.dat . Other related data and papers at http://www.fis.uniroma3.it/~ELAIS_S/ . Few luminosities in Table 2 corrected

[Abridged]We exploit a large homogeneous dataset to derive a self-consistent picture of IR emission based on the time-dependent 24, 15, 12 and 8micron monochromatic and bolometric IR luminosity functions (LF) over the 01. The mean redshift of the peak in the source number density shifts with luminosity: the brighest IR galaxies appear to be forming stars earlier in cosmic time (z>1.5), while the less luminous ones keep doing it at more recent epochs (z~1 for L(IR)1. We also seem to find a difference in the evolution rate of the source number densities as a function of luminosity, a downsizing evolutionary pattern similar to that reported from other samples of cosmic sources., Comment: Accepted for pubblicantion in Astronomy and Astrophysics

We present the first estimate of the evolution of type 1 AGNs in the IR (15 μm) obtained from the ELAIS survey in the S1 region. We find that the luminosity function (LF) of Type 1 AGNs at 15μm is fairly well represented by a double power-law function with a bright slope of 2.9 and a faint slope of 1.1. There is evidence for significant cosmological evolution according to a pure luminosity evolution model L15(z)α(l+z)k, with in a (Ωm,ΩΛ)=(1.0,0.0) cosmology. This evolution is similar to what is observed at other wavebands. From the luminosity function and its evolution, we estimate a contribution of ~ 2% from Type 1 AGN to the total Cosmic Infrared Background (CIRB) at 15 μm.

We present a catalog of optical spectroscopic identifications of sources detected by Spitzer at 3.6 or 24 micron down to 10 and 280 microJy, respectively, in the SWIRE/XMM-Newton/ELAIS-S1 field and classified via line width analysis and diagnostic diagrams. A total of 1376 sources down to R~24.2 mag have been identified (1362 detected at 3.6 micron, 419 at 24 micron, and 405 at both) by low-resolution optical spectroscopy carried out with FORS2, VIMOS, and EFOSC2 at the Very Large Telescope and 3.6m ESO telescopes. The spectroscopic campaigns have been carried out over the central 0.6 square degrees area of ELAIS-S1 which, in particular, has also been observed by XMM-Newton and Chandra. We find the first direct optical spectroscopic evidence that the fraction of active galactic nuclei (AGN; mostly AGN2) increases with increasing F(24 micron)/F(R) ratio, reaching values of 70(+/-20)% in the range 316, Comment: Accepted for publication in the Astrophysical Journal. 15 pages, 17 figures, 2 tables

A. Molino et al., The Advance Large Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) survey has observed eight different regions of the sky, including sections of the Cosmic Evolution Survey (COSMOS), DEEP2, European Large-Area Infrared Space Observatory Survey (ELAIS), Great Observatories Origins Deep Survey North (GOODS-N), Sloan Digital Sky Survey (SDSS) and Groth fields using a new photometric system with 20 optical, contiguous ~300-Å filters plus the JHKs bands. The filter system is designed to optimize the effective photometric redshift depth of the survey, while having enough wavelength resolution for the identification of faint emission lines. The observations, carried out with the Calar Alto 3.5-m telescope using the wide-field optical camera Large Area Imager for Calar Alto (LAICA) and the near-infrared (NIR) instrument Omega-2000, represent a total of ~700 h of on-target science images. Here we present multicolour point-spread function (PSF) corrected photometry and photometric redshifts for ~438 000 galaxies, detected in synthetic F814W images. The catalogues are complete down to a magnitude I~24.5AB and cover an effective area of 2.79 deg2. Photometric zero-points were calibrated using stellar transformation equations and refined internally, using a new technique based on the highly robust photometric redshifts measured for emission-line galaxies. We calculate Bayesian photometric redshifts with the Bayesian Photometric Redshift (BPZ)2.0 code, obtaining a precision of δz/(1+zs)=1 per cent for I, We acknowledge financial support from the Spanish MICINN under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC. Part of this work was supported by Junta de Andalucía, through grant TIC-114 and the Excellence Project P08-TIC-3531, and by the Spanish Ministry for Science and Innovation through grants AYA2006-1456, AYA2010-15169, AYA2010-22111-C03-02, AYA2010-22111-C03-01 and Generalitat Valenciana project Prometeo 2009/064.

We present the first set of XMM-Newton EPIC observations in the 2 square degree COSMOS field. The strength of the COSMOS project is the unprecedented combination of a large solid angle and sensitivity over the whole multiwavelength spectrum. The XMM-Newton observations are very efficient in localizing and identifying active galactic nuclei (AGN) and clusters as well as groups of galaxies. One of the primary goals of the XMM-Newton Cosmos survey is to study the co-evolution of active galactic nuclei as a function of their environment in the Cosmic web. Here we present the log of observations, images and a summary of first research highlights for the first pass of 25 XMM-Newton pointings across the field. In the existing dataset we have detected 1416 new X-ray sources in the 0.5-2, 2-4.5 and 4.5-10 keV bands to an equivalent 0.5-2 keV flux limit of 7x10-16 erg cm-2 s-1. The number of sources is expected to grow to almost 2000 in the final coverage of the survey. From an X-ray color color analysis we identify a population of heavily obscured, partially leaky or reflecting absorbers, most of which are likely to be nearby, Compton-thick AGN., 9 pages, ApJS COSMOS Special Issue, 2007 in press. the full-resolution version is available at http://www.mpe.mpg.de/XMMCosmos/PAPERS/grh_cosmos.ps.gz

We present data analysis and X-ray source counts for the first season of XMM-Newton observations in the COSMOS field. The survey covers ~2 deg2 within the region of sky bounded by 09h57m30sh03m30s, 01deg27'30''deg57'30'' with a total net integration time of 504 ks. A maximum likelihood source detection was performed in the 0.5-2, 2-4.5, and 4.5-10 keV energy bands, and 1390 pointlike sources were detected in at least one band. Detailed Monte Carlo simulations were performed to fully test the source-detection method and to derive the sky coverage to be used in the computation of the logN-logS relations. These relations were then derived in the 0.5-2, 2-10, and 5-10 keV energy bands, down to flux limits of 7.2×10-16 ergs cm-2 s-1, 4.0×10-15 ergs cm-2 s-1, and 9.7×10-15 ergs cm-2 s-1, respectively. Thanks to the large number of sources detected in the COSMOS survey, the logN-logS curves are tightly constrained over a range of fluxes which were poorly covered by previous surveys, especially in the 2-10 and 5-10 keV bands. The 0.5-2 and 2-10 keV differential logN-logS relations were fitted with a broken power-law model which revealed a Euclidean slope at the bright end and a flatter slope (α~1.5) at faint fluxes. In the 5-10 keV energy band a single power law provides an acceptable fit to the observed source counts with a slope α~2.4. A comparison with the results of previous surveys shows good agreement in all the energy bands under investigation in the overlapping flux range. We also notice a remarkable agreement between our logN-logS relations and the most recent model of the X-ray background. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; also based on data collected at the Canada-France-Hawaii Telescope operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France, and the University of Hawaii.

Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) is photometric survey designed to trace the cosmic evolution and cosmic variance. It covers a large area of ~4 deg2 in eight fields, where seven fields overlap with other surveys, allowing us to have complementary data in other wavelengths. All observations were carried out in 20 continuous, medium band (30 nm width) optical and 3 near-infrared (JHK) bands, providing the precise measurements of photometric redshifts. In addition, morphological classification of galaxies is crucial for any kind of galaxy formation and cosmic evolution studies, providing the information about star formation histories, their environment and interactions, internal perturbations, etc. We present a morphological classification of >40 000 galaxies in the ALHAMBRA survey. We associate to every galaxy a probability to be early type using the automated Bayesian code GALSVM. Despite of the spatial resolution of theALHAMBRAimages (~1 arcsec), for 22 051 galaxies, we obtained the contamination by other type of less than 10 per cent. Of those, 1640 and 10 322 galaxies are classified as early-(down to redshifts ~0.5) and late-type (down to redshifts ~1.0), respectively, with magnitudes F613W ≤ 22.0. In addition, for magnitude range 22.0 < F613W ≤ 23.0, we classified other 10 089 late-type galaxies with redshifts ≤1.3.We show that the classified objects populate the expected regions in the colour-mass and colour-magnitude planes. The presented data set is especially attractive given the homogeneous multiwavelength coverage available in the ALHAMBRA fields, and is intended to be used in a variety of scientific applications. The low-contamination catalogue (, This research was supported by the Junta de Andalucía through projects PO8-TIC-03531 and TIC114, the Spanish Ministry of Economy and Competitiveness (MINECO) through projects AYA2006-14046, AYA2010-15169, AYA2010-22111-C03-02, AYA2011-29517-C03-01, and the Generalitat Valenciana through project GV/Prometeo 2009/064. MP acknowledges financial support from JAE-Doc program of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.

[Aims]: We aim to illustrate the potentiality of the Advanced Large, Homogeneous Area, Medium-Band Redshift Astronomical (ALHAMBRA) survey to investigate the high-redshift universe through the detection of quasi stellar objects (QSOs) at redshifts higher than 5. [Methods]: We searched for QSOs candidates at high redshift by fitting an extensive library of spectral energy distributions-including active and non-active galaxy templates, as well as stars-to the photometric database of the ALHAMBRA survey (composed of 20 optical medium-band plus the 3 broad-band JHKs near-infrared filters). [Results]: Our selection over ≈1 square degree of ALHAMBRA data (∼1/4 of the total area covered by the survey), combined with GTC/OSIRIS spectroscopy, has yielded identification of an optically faint QSO at very high redshift (z = 5.41). The QSO has an absolute magnitude of ∼-24 at the 1450 Å continuum, a bolometric luminosity of ≈2 × 1046 erg s -1, and an estimated black hole mass of ≈108 M ⊙. This QSO adds itself to a reduced number of known UV faint sources at these redshifts. The preliminary derived space density is compatible with the most recent determinations of the high-z QSO luminosity functions. This new detection shows how ALHAMBRA, as well as forthcoming well-designed photometric surveys, can provide a wealth of information on the origin and early evolution of this kind of object. © 2013 ESO., Part of this work was supported by Junta de Andalucía, through grant TIC-114 and the Excellence Project P08-TIC-3531, and by the Spanish Ministry for Science and Innovation through grants AYA2006-1456, AYA2010-15169, and AYA2010-22111-C03-02, and Generalitat Valenciana project Prometeo 2008/132. M.P. acknowledges financial support from the JAE-Doc programme of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.

We take advantage of the exceptional photometric coverage provided by the combination of GALEX data in the ultraviolet (UV) and the ALHAMBRA survey in the optical and near-infrared to analyse the physical properties of a sample of 1225 GALEX-selected Lyman break galaxies (LBGs) at 0.8 ≲ z ≲ 1.2 that are located in the COSMOS field. This is the largest sample of LBGs studied in this redshift range to date. According to a spectral energy distribution (SED) fitting with synthetic stellar population templates, we find that LBGs at z ̃ 1 are mostly young galaxies with a median age of 341 Myr and have intermediate dust attenuation, (Es(B - V)) ̃ 0.20. Owing to the selection criterion, LBGs at z ̃ 1 are UV-bright galaxies and have a high dust-corrected total star formation rate (SFR), with a median value of 16.9M⊙ yr-1. Their median stellar mass is log (M*/M⊙) = 9.74. We find that the dustcorrected total SFR of LBGs increases with stellar mass and that the specific SFR is lower for more massive galaxies (downsizing scenario). Only 2 per cent of the galaxies selected through the Lyman break criterion have an active galactic nucleus nature. LBGs at z ̃ 1 are located mostly over the blue cloud of the colour-magnitude diagram of galaxies at their redshift, with only the oldest and/or the dustiest deviating towards the green valley and red sequence. Morphologically, 69 per cent of LBGs are disc-like galaxies, with the fractions of interacting, compact, or irregular systems being much lower, below 12 per cent. LBGs have a median effective radius of 2.5 kpc, and larger galaxies have a higher total SFR and stellar mass. Compared with their high-redshift analogues, we find evidence that LBGs at lower redshifts are larger, redder in the UV continuum, and have a major presence of older stellar populations in their SEDs. However, we do not find significant differences in the distributions of stellar mass or dust attenuation. ©2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society., This research has been supported by the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AYA2011-29517-C03-01. Funding for the SDSS and SDSS-II was provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. Financial support from the Spanish grant AYA2010-15169 and from the Junta de Andalucía through TIC-114 and the Excellence Project P08-TIC-03531 is acknowledged.

This contribution presents how the Ethical Matrix was used in teaching and evaluating a course on ‘Ethics of Food and Nutrition Security’ (EFNS) at Hohenheim University in the winter semester 2010/2011 and in the winter semester 2011/12. We will first provide some information on the development of the course and present the results of the general evaluation of the course by the department. We will then introduce the newly developed instrument in which the Ethical Matrix was embedded. The instrument aims at testing individual skills necessary for identifying ethical issues. Finally, we will draw some conclusions that refer to the further development of the instrument.

We constrain the space density and properties of massive galaxy candidates at redshifts of z>=3.5 in the GOODS-N field. By selecting sources in the Spitzer+IRAC bands, a highly stellar mass-complete sample is assembled,including massive galaxies which are very faint in the optical/near-IR bands that would be missed by samples selected at shorter wavelengths. The z>=3.5 sample was selected down to 23 mag at 4.5 micron using photometric redshifts that have been obtained by fitting the galaxies SEDs at optical, near-IR and IRAC bands. We also require that the brightest band in which candidates are detected is the IRAC 8 micron band in order to ensure that the near-IR 1.6 micron (rest-frame) peak is falling in or beyond this band. We found 53 z>=3.5 candidates, with masses in the range of M~10^10-10^11M_sun. At least ~81% of these galaxies are missed by traditional Lyman Break selection methods based on UV light. Spitzer+MIPS emission is detected for 60% of the sample of z>=3.5 galaxy candidates. Although in some cases this might suggest a residual contamination from lower redshift star-forming galaxies or AGN, 37% of these objects are also detected in the sub-mm/mm bands in recent SCUBA,AzTEC and MAMBO surveys, and have properties fully consistent with vigorous starburst galaxies at z>=3.5. The comoving number density of galaxies with stellar masses >= 5x10^10M_sun(a reasonable stellar mass completeness limit for our sample) is 2.6x10^-5Mpc^-3 (using the volume within 3.5, Comment: Accepted by A&A; 35 pages, 15 figures, references updated

We present the broad-band Spectral Energy Distributions (SEDs) of the largest available highly (72%) complete spectroscopic sample of mid-infrared (MIR) selected galaxies and AGN at intermediate redshift. The sample contains 203 extragalactic sources from the 15-micron survey in the ELAIS-SWIRE field S1, all with measured spectroscopic redshift. Most of these sources have full multi-wavelength coverage from the far-UV to the far-infrared and lie in the redshift range 0.110 mJy, while that obtained from optical spectroscopy never being >30%, even at the higher flux densities. The results of this work will be very useful for updating all the models aimed at interpreting the deep infrared survey data and, in particular, for constraining the nature and the role of dust-obscured systems in the intermediate/high-redshift Universe., Comment: Accepted for publication in The Astrophysical Journal. Scheduled for the ApJ August 20, 2008, v683 n 2 issue. 33 pages: 22 pages of main text + 2 tables + 6 postscript figures, use aastex

(abridged) The ESIS survey is the optical follow up of the SWIRE/Spitzer in the ELAIS-S1 region of the sky. In the era of observational cosmology, the main efforts are focused on the study of galaxy evolution and its environmental dependence. Wide area, multiwavelength, extragalactic surveys are needed in order to probe sufficiently large volumes, minimize cosmic variance and find significant numbers of rare objects. We present VIMOS I and z band imaging belonging to the ESIS survey. A total of ~4 deg2 were targeted in I and ~1 deg2 in z. More than 300000 galaxies have been detected in the I band and ~50000 in the z band. Object coordinates are defined within an uncertainty of ~0.2 arcsec r.m.s., with respect to GSC 2.2. We reach a 90% average completeness at 23.1 and 22.5 mag (Vega) in the I and z bands, respectively. On the basis of IRAC colors, we identified galaxies having the 1.6 um stellar peak shifted to z=1-3. The new I, z band data provide reliable constraints to avoid low-redshift interlopers and reinforce this selection. Roughly 1000 galaxies between z=2-3 were identified over the ESIS ~4 deg2, at the SWIRE 5.8 um depth (25.8 uJy at 3sigma). These are the best galaxy candidates to dominate the massive tail (M>1e11 Msun) of the z>2 mass function., Accepted for publication on A&A. The quality of some figures has been degraded for arXiv purposes. More information about the ESIS survey is available at http://www.astro.unipd.it/esis/

We present optical identifications and a multi-band catalogue of a sample of 478 X-ray sources in the XMM and Chandra surveys of the central 0.6 deg^2 of the ELAIS-S1 field. The optical/infrared counterpart of each X-ray source was identified using R and IRAC 3.6 um bands. This method was complemented by the precise positions obtained through Chandra observations. Approximately 94% of the counterparts are detected in the R band, while the remaining are blank fields in the optical down to R~24.5, but have a near-infrared counterpart detected by IRAC within 6 arcsec from the XMM centroid. The multi-band catalogue contains photometry in ten photometric bands (B to the MIPS 24 um). We determined redshift and classification for 237 sources (~50% of the sample) brighter than R=24. We classified 47% of the sources with spectroscopic redshift as broad-line active galactic nuclei (BL AGNs) with z=0.1-3.5, while sources without broad-lines are about 46% of the spectroscopic sample and are found up to z=2.6. We identified 11 type 2 QSOs among the sources with X/O>8, with z=0.9-2.6, high 2-10 keV luminosity (log(L2-10keV)>=43.8 erg/s) and hard X-ray colors suggesting large absorbing columns at the rest frame (logN_H up to 23.6 cm^-2). BL AGNs show on average blue optical-to-near-infrared colors, softer X-ray colors and X-ray-to-optical colors typical of optically selected AGNs. Conversely, narrow-line sources show redder optical colors, harder X-ray flux ratio and span a wider range of X-ray-to-optical colors. On average the SEDs of high-luminosity BL AGNs resemble the power-law typical of unobscured AGNs. The SEDs of NOT BL AGNs are dominated by the galaxy emission in the optical/near-infrared, and show a rise in the mid-infrared which suggests the presence of an obscured active nucleus., 15 pages, A&A accepted, affiliations corrected

(Abridged) We selected high-z massive galaxies at 5.8 microns, in the SWIRE ELAIS-S1 field (1 sq. deg.). Galaxies with the 1.6 microns stellar peak redshifted into the IRAC bands (z~1-3, called ``IR-peakers'') were identified. Stellar masses were derived by means of spectro-photometric fitting and used to compute the stellar mass function (MF) at z=1-2 and 2-3. A parametric fit to the MF was performed, based on a Bayesian formalism, and the stellar mass density of massive galaxies above z=2 determined. We present the first systematic study of the very-massive tail of the galaxy stellar mass function at high redshift. A total of 326 sources were selected. The majority of these galaxies have stellar masses in excess of 1e11 Msun and lie at z>1.5. The availability of mid-IR data turned out to be a valuable tool to constrain the contribution of young stars to galaxy SEDs, and thus their M(stars)/L ratio. The influence of near-IR data and of the chosen stellar library on the SED fitting are also discussed. A significant evolution is found not only for galaxies with M~1e11 Msun, but also in the highest mass bins considered. The comoving number density of these galaxies was lower by more than a factor of 10 at z=2-3, with respect to the local estimate. SWIRE 5.8 micron peakers more massive than 1.6x1e11 Msun provide 30-50% of the total stellar mass density in galaxies at z=2-3., Accepted for publication on A&A. 31 pages. The quality of some figures has been degraded for arXiv purposes

Context: The counts of galaxies and AGN in the mid infra-red (MIR) bands are important instruments for studying their cosmological evolution. However, the classic spectral line ratios techniques can become misleading when trying to properly separate AGN from starbursts or even from apparently normal galaxies. Aims: We use X-ray band observations to discriminate AGN activity in previously classified MIR-selected starburst galaxies and to derive updated AGN1 and (Compton thin) AGN2 counts at 15 um. Methods: XMM observations of the ELAIS-S1 15um sample down to flux limits ~2x10^-15 erg cm^-2 s^-1 (2-10 keV band) were used. We classified as AGN all those MIR sources with a unabsorbed 2-10 keV X-ray luminosity higher that ~10^42 erg/s. Results: We find that at least about 13(+/-6) per cent of the previously classified starburst galaxies harbor an AGN. According to these figures, we provide an updated estimate of the counts of AGN1 and (Compton thin) AGN2 at 15 um. It turns out that at least 24% of the extragalactic sources brighter than 0.6 my at 15 um are AGN (~13% contribution to the extragalactic background produced at fluxes brighter than 0.6 mJy)., Comment: Accepted for publication on A&A

We present optical and X-ray data for a sample of serendipitous XMM-Newton sources that are selected to have 0.5-2 versus 2-4.5 keV X-ray hardness ratios which are harder than the X-ray background. The sources have 2-4.5 keV X-ray flux ≥10-14 erg cm-2 s-1, and in this paper we examine a subsample of 42 optically bright (r < 21) sources; this subsample is 100 per cent spectroscopically identified. All but one of the optical counterparts are extragalactic, and we argue that the single exception, a Galactic M star, is probably a coincidental association rather than the correct identification of the X-ray source. The X-ray spectra of all the sources are consistent with heavily absorbed power laws (21.8 < log NH < 23.4), and all of them, including the two sources with 2-10 keV intrinsic luminosities of 1044 erg s-1, and two of these sources have optical spectra which are dominated by narrow emission lines, that is, are type 2 QSOs. Only a small fraction of the sources (7/42) show broad optical emission lines, and all of these have NH < 1023 cm-2. This implies that ratios of X-ray absorption to optical/ultraviolet extinction equivalent to >100 times the Galactic gas-to-dust ratio are rare in AGN absorbers (at most a few per cent of the population), and may be restricted to broad absorption line QSOs. Seven objects appear to have an additional soft X-ray component in addition to the heavily absorbed power law; all seven are narrow emission-line objects with z < 0.3 and 2-10 keV intrinsic luminosities 4 per cent of broad-line AGN (BLAGN) have ionized absorbers that attenuate their soft X-ray flux by >50 per cent. In at least one of the X-ray-absorbed BLAGN in our sample the X-ray spectrum requires an ionized absorber, consistent with this picture., FJC acknowledges financial support from the Spanish Ministerio de Educacion Ciencia, under projects ESP2003-00812 and ESP2006-13608-C02-01. RDC and PS acknowledge partial financial support by the MIUR (Cofin-03-02-23) and INAF.

AIMS: We present the optical classification and redshift of 348 X-ray selected sources from the XMM-Newton Bright Serendipitous Survey (XBS) which contains a total of 400 objects (identification level = 87%). About 240 are new identifications. In particular, we discuss in detail the classification criteria adopted for the Active Galactic Nuclei population. METHODS: By means of systematic spectroscopic campaigns and through the literature search we have collected an optical spectrum for the large majority of the sources in the XBS survey and applied a well-defined classification ``flow-chart''. RESULTS: We find that the AGN represent the most numerous population at the flux limit of the XBS survey (~10^-13 erg cm^-2 s^-1) constituting 80% of the XBS sources selected in the 0.5-4.5 keV energy band and 95% of the ``hard'' (4.5-7.5 keV) selected objects. Galactic sources populate significantly the 0.5-4.5 keV sample (17%) and only marginally (3%) the 4.5-7.5 keV sample. The remaining sources in both samples are clusters/groups of galaxies and normal galaxies (i.e. probably not powered by an AGN). Furthermore, the percentage of type2 AGN (i.e. optically absorbed AGNs with A_V>2mag) dramatically increases going from the 0.5-4.5 keV sample (f=N_AGN2/N_AGN=7%) to the 4.5-7.5 keV sample (f=32%). We finally propose two simple diagnostic plots that can be easily used to obtain the spectral classification for relatively low redshift AGNs even if the quality of the spectrum is not good., 14 pages plus 7 additional pages of table, accepted for publication on A&A

We study the evolution of the luminosity function (LF) of type-1 and type-2 AGN in the mid-infrared, and derive their contribution to the Cosmic InfraRed Background (CIRB) and the expected deep source counts to be observed by Spitzer at 24 micron. The sample of type-1 and type-2 AGN was selected at 15 micron (ISO) and 12 micron (IRAS), and classified on the basis of their optical spectra. Local templates of type-1 and type-2 AGN have been used to derive the intrinsic 15 micron luminosities. We adopted an evolving smooth two-power law shape of the LF, whose parameters have been derived using an un-binned maximum likelihood method. We find that the LF of type-1 AGN is compatible with a pure luminosity evolution (L(z)=L(0)(1+z)^k_L) model where k_L~2.9. A small flattening of the faint slope of the LF with increasing redshift is favoured by the data. A similar evolutionary scenario is found for the type-2 population with a rate k_L ranging from ~1.8 to 2.6, depending significantly on the adopted mid-infrared spectral energy distribution. Also for type-2 AGN a flattening of the LF with increasing redshift is suggested by the data, possibly caused by the loss of a fraction of type-2 AGN hidden within the optically classified starburst and normal galaxies. The type-1 AGN contribution to the CIRB at 15 micron is (4.2-12.1) x 10e-11 W m^-2 sr^-1, while the type-2 AGN contribution is (5.5-11.0) x 10e-11 W m^-2 sr^-1. We expect that Spitzer will observe, down to a flux limit of S_24 = 0.01 mJy, a density of ~1200 deg^-2 type-1 and ~1000 deg^-2 type-2 optically classified AGN. The derived total contribution of the AGN galaxies to the CIRB (4-10%) and Spitzer counts should be considered as lower limits, because of a possible loss of type-2 sources caused by the optical classification., 14 pages, 10 figures. Accepted for publication in Astronomy & Astrophysics

[ABRIGED] We present the optical identification of a sample of 695 X-ray sources detected in the first 1.3 deg^2 of the XMM-COSMOS survey, down to a 0.5-2 keV (2-10 keV) limiting flux of ~10^-15 erg cm-2 s-1 (~5x10^-15 erg cm^-2 s-1). We were able to associate a candidate optical counterpart to ~90% (626) of the X-ray sources, while for the remaining ~10% of the sources we were not able to provide a unique optical association due to the faintness of the possible optical counterparts (I_AB>25) or to the presence of multiple optical sources within the XMM-Newton error circles. We also cross-correlated the candidate optical counterparts with the Subaru multicolor and ACS catalogs and with the Magellan/IMACS, zCOSMOS and literature spectroscopic data; the spectroscopic sample comprises 248 objects (~40% of the full sample). Our analysis reveals that for ~80% of the counterparts there is a very good agreement between the spectroscopic classification, the morphological parameters as derived from ACS data, and the optical to near infrared colors. About 20% of the sources show an apparent mismatch between the morphological and spectroscopic classifications. All the ``extended'' BL AGN lie at redshift, 17 pages, ApJS COSMOS Special Issue, 2007 in press. Full resolution version is available at http://www.mpe.mpg.de/XMMCosmos/PAPERS/

We report on the first SCUBA detection of a Type 2 QSO at z=3.660 in the Chandra Deep Field South. This source is X-ray absorbed, shows only narrow emission lines in the optical spectrum and is detected in the sub-mm: it is the ideal candidate in an evolution scheme for AGN (e.g. Fabian (1999); Page et al. (2004)) of an early phase corresponding to the main growth of the host galaxy and formation of the central black hole. The overall photometry (from the radio to the X-ray energy band) of this source is well reproduced by the spectral energy distribution (SED) of NGC 6240, while it is incompatible with the spectrum of a Type 1 QSO (3C273) or a starburst galaxy (Arp 220). Its sub-mm (850 \mu m) to X-ray (2 keV) spectral slope (alpha_SX) is close to the predicted value for a Compton-thick AGN in which only 1% of the nuclear emission emerges through scattering. Using the observed flux at 850 \mu m we have derived a SFR=550--680 M$_odot/yr and an estimate of the dust mass, M$_dust=4.2 10^8 M_odot

We investigate the clustering properties of galaxies in the recently completed ELAIS-S1 redshift survey through their spatial two point autocorrelation function. We used a sub-sample of the ELAIS-S1 catalog covering approximately 4 deg^2 and consisting of 148 objects selected at 15 micron with a flux >0.5 mJy and redshift z, Comment: 7 pages, 5 .ps figures, accepted for pubblication in MNRAS

We present the first measure of the evolution of type I and 2 active galactic nuclei (AGN1 and AGN2) in the mid-infrared (15 mu m). We used a sample of 52 AGN selected from the southern ELAIS fields combined with a local sample of 91 AGN from the IRAS Faint Source Catalog. We find that AGN1. follow a luminosity dependent luminosity evolution with a rate k(L)=2.6, which stops at z larger than 2. A similar evolutionary scenario is found for AGN2 with k(L)=2.0-2.6, depending on the adopted k-correction. We estimate that AGN1 contribute about 3% to the cosmic mid-infrared background, while the AGN2 contribution is about 10%.

We report the discovery of seven high proper motion stars with proper motions between about 0.7 and 2.2 arcsec/yr. They were detected in an archival search using multi-epoch positions in the optical SuperCOSMOS Sky Surveys and in the near-infrared sky surveys 2MASS and DENIS. The star with the largest proper motion, is spectroscopically classified as a very nearby (d=8pc) M5.5 dwarf with Galactic thin disk kinematics. A second star with about 2 arcsec/yr proper motion, is still lacking spectroscopic confirmation but can be classified from photometry as thick disk M3.5 dwarf. Three objects turn out to be cool subdwarf members of the Galactic thick disk or halo, including the first sdM9.5 object, which represents the currently coolest known M subdwarf, another ultra-cool subdwarf, of spectral type sdM7.0 as well as an earlier type (sdM1.5) star. The latter has an extremely large space velocity with clear halo kinematics. Two objects show featureless spectra typical of cool white dwarfs. One of them is probably a very nearby (d~4pc) thin disk object and may be the nearest isolated white dwarf, the other one has thick disk kinematics., 9 pages, 4 figures, accepted for publication in Astronomy and Astrophysics

We present the final band-merged ELAIS catalogue at 6.7, 15, 90, and 175 $��$m, and the associated data at u,g,r,i,z,J,H,K, and 20cm. The origin of the survey, infrared and radio observations, data-reduction and optical identifications are briefly reviewed, and a summary of the area covered, and completeness limit for each infrared band is given. A detailed discussion of the band-merging and optical association strategy is given. The total catalogues consists of 2860 sources. For extragalactic sources observed in 3 or more infrared bands, colour-colour diagrams are presented and discussed in terms of the contributing infrared populations. Spectral energy distributions are shown for selected sources and compared with cirrus, M82 and Arp220 starburst, and AGN dust torus models. Spectroscopic redshifts are tabulated, where available. For the N1 and N2 areas, the INT ugriz Wide Field Survey, permits photometric redshifts to be estimated for galaxies and quasars. These agree well with the spectroscopic redshifts, within the uncertainty of the photometric method. The redshift distribution is given for selected ELAIS bands and colour-redshift diagrams are discussed. There is a high proportion of ultraluminous infrared galaxies in the ELAIS Catalogue ($> 10 %$ of 15 $��$m sources), many with Arp220-like colours. 10 hyperluminous infrared galaxies and 10 EROs are found in the survey. The large numbers of ultraluminous galaxies imply very strong evolution in the star-formation rate between z = 0 and 1., 21 pages, 31 figures. Accepted for publication in MNRAS

We present the results from the spectroscopic identifications of the ELAIS sources in the southern fields S1 and S2. Two main extragalactic classes have been found: z

The radio counterparts to the 15-micron sources in the European Large Area ISO Survey southern fields are identified in 1.4-GHz maps down to about 80 microJy. The radio-MIR correlation is investigated and derived for the first time at these flux densities for a sample of this size. Our results show that radio and MIR luminosities correlate almost as well as radio and FIR, at least up to z ~ 0.6. Using the derived relation and its spread together with the observed 15-micron counts, we have estimated the expected contribution of the 15-micron extragalactic populations to the radio source counts and the role of MIR starburst galaxies in the well known 1.4-GHz source excess observed at sub-mJy levels. Our analysis demonstrates that IR emitting starburst galaxies do not contribute significantly to the 1.4-GHz counts for strong sources, but start to become a significant fraction of the radio source population at flux densities < 0.5 - 0.8 mJy. They are expected to be responsible for more than 60% of the observed radio counts at < 0.05 mJy. These results are in agreement with the existing results on optical identifications of faint radio sources., 6 pages, 3 postscript figures, Accepted for publication as Letter in MNRAS

Resumen tomado del autor En el presente estudio se han controlado y analizado los valores medios de la potencia desarrollada por un grupo de escaladores de competición, durante el periodo de preparación. Participaron en la investigación de forma voluntaria, cuatro hombres y una mujer. Según los resultados observados, los autores opinan que con elevados registros de potencia ante cargas similares a la de competición, los deportistas suelen alcanzar sus mejores resultados, sobre todo en las modalidades en las que intervenga el factor tiempo. En escalada, el deportista siempre realiza los movimientos de progresión soportando como resistencia su propio peso, por tanto, el valor de potencia que resulta más relevante es aquel que se desarrolle ante cargas externas que se identifiquen con el peso corporal. Con relación a la potencia desarrollada en el nivel de la fuerza útil, los sujetos muestran registros y procesos singulares. Cataluña Universitat de les Illes Balears. Redined Illes Balears; Edifici Guillem Cifre de Colonya. Ctra. de Valldemossa, Km 7,5; 07122 Palma; +34971172792; +34971173190; redined.balears@uib.es ESP

We present the 15-mum luminosity function of type 1 active galactic nuclei (AGN1; quasi-stellar object+Seyfert 1). Our sample of 21 high-redshift sources is selected from the Preliminary Analysis catalogue in the S1 field of the European Large Area ISO Survey (ELAIS). To study the cosmological evolution of the AGN1 luminosity function, our sample has been combined with a local sample of 41 sources observed by IRAS . We find that the luminosity function of AGN1 at 15 mum is fairly well represented by a double-power-law-function. There is evidence for significant cosmological evolution consistent with a pure luminosity evolution (PLE) model L(z )proportional to(1+z ) (kL), with k(L) =3.0-3.3. The value of k(L) depends on the existence or non-existence of an evolution cut-off at redshift similar to2, and on the adopted cosmology. From the luminosity function and its evolution we estimate a contribution of AGN1 to the cosmic infrared background (CIRB) of nuI(nu) similar to 6x10(-11) W m(-2) sr(-1) at 15 mum. This corresponds to similar to2-3 per cent of the total observed CIRB at this wavelength. Under the usual assumptions of unified models for AGN, the expected contribution of the whole AGN population to the CIRB at 15 mum is 10-15 per cent.

[Context]: Even the spectroscopic capabilities of today's ground and space-based observatories can not keep up with the enormous flow of detections (>10 5 deg -2) unveiled in modern cosmological surveys as: i) would be required enormous telescope time to perform the spectroscopic follow-ups and ii) spectra remain unattainable for the fainter detected population. In the past decade, the typical accuracy of photometric redshift (photo-z) determination has drastically improved. Nowdays, it has become a perfect complement to spectroscopy, closing the gap between photometric surveys and their spectroscopic follow-ups. The photo-z precision for active galactic nuclei (AGN) has always lagged behind that for the galaxy population owing to the lack of proper templates and their intrinsic variability. [Aims]: Our goal is to characterize the ability of the Advanced Large, Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) survey in assigning accurate photo-z's to broad-line AGN (BLAGN) and quasi-stellar objects (QSOs) based on their ALHAMBRA very-low-resolution optical-near-infrared (NIR) spectroscopy. This will serve as a benchmark for any future compilation of ALHAMBRA selected QSOs and the basis for the statistical analysis required to derive luminosity functions up to z ∼ 5. [Methods]: We selected a sample of spectroscopically identified BLAGN and QSOs and used a library of templates (including the SEDs of AGN and both normal and starburst galaxies, as well as stars) to fit the 23 photometric data points provided by ALHAMBRA in the optical and NIR (20 medium-band optical filters plus the standard JHKs). [Results]: We find that the ALHAMBRA photometry is able to provide an accurate photo-z and spectral classification for ~88% of the 170 spectroscopically identified BLAGN/QSOs over 2.5≠deg 2 in different areas of the survey and brighter than m 678 = 23.5 (equivalent to r SLOAN ~ 24.0). The derived photo-z accuracy is below 1% and is comparable to the most recent results in other cosmological fields that use photometric information over a wider wavelength range. The fraction of outliers (∼12%) is mainly caused by the larger photometric errors for the faintest sources and the intrinsic variability of the BLAGN/QSO population. A small fraction of outliers may have an incorrectly assigned spectroscopic redshift. [Conclusions]: The definition of the ALHAMBRA survey in terms of the number of filters, filter properties, areal coverage, and depth is able to provide photometric redshifts for BLAGN/QSOs with a precision similar to any previous survey that makes use of medium-band optical photometry. In agreement with previous literature results, our analysis also reveals that, in the 0 < z < 4 redshift interval, very accurate photo-z can be obtained without the use of NIR broadband photometry at the expense of a slight increase in the outliers. The importance of NIR data is expected to increase at higher z (z > 4). These results are relevant for the design of future optical follow-ups of surveys containing a large fraction of BLAGN, such as many X-ray or radio surveys. © 2012 ESO., Part of this work was supported by Junta de Andalucía, through grant TIC-114 and the Excellence Project P08-TIC-3531, and by the Spanish Ministry for Science and Innovation through grants AYA2006-1456, AYA2010-15169, AYA2010-22111-C03-02, and AYA2011-29517-C03-01.

The case of a 50 years old man with polycystic liver and kidneys and ascites which had been diagnosed by laparoscopy and pyeloureterography, is reported. Chronic renal failure was the cause of death, and obvious signs of portal hypertension were found at necropsy. The loss of hepatic structure produced by pericystic fibrosis, regenerative nodules, thrombosis of portal branches, and necrotic areas, is stressed as an important cause of portal hypertension. This pathogenesis could be similar to that of cirrhosis. Both portal hypertension and ascites are highly uncommon facts in adults' polycystic livers.