What is the redshift of the gamma- ray BL Lac source S4 0954+65?

High signal-to-noise ratio spectroscopic observations of the BL Lac object S4 0954+65 at the alleged redshift z = 0.367 are presented. This source was detected at gamma frequencies by MAGIC (TeV) and FERMI (GeV) telescopes during a remarkable outburst that occurred in February 2015, making the determination of its distance particularly relevant for our understanding of the properties of the Extragalactic Background Light. Contrary to previous reports on the redshift, we found that the optical spectrum is featureless at an equivalent width limit of \sim 0.1 Ang. A critical analysis of the existing observations indicates that the redshift is still unknown. Based on the new data we estimate a lower limit to the redshift at z \geq 0.45.Comment: Minor comment and accepted for publication in Astronomical Journa

Optical spectroscopic observations of gamma-ray blazar candidates II. The 2013 KPNO campaign in the Northern Hemisphere

We recently started a systematic search of low-energy counterparts of the unidentified gamma-ray sources (UGSs) listed in the Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) and the Fermi-LAT 2-Year Source Catalog (2FGL).} The main goal of our investigation is to find active galaxies belonging to the blazar class that lie within the positional uncertainty region of the UGSs and thus could be their potential low-energy counterparts. To achieve our aims, we first adopted several procedures based on the peculiar observational properties of blazars in the radio and in the IR. Then we carried out a follow-up spectroscopic campaign in the optical band to verify the nature of the candidates selected as potential counterparts of the UGSs. Here we present the results of the observations carried out in 2013 in the Northern Hemisphere at Kitt Peak National Observatory (KPNO). Optical spectroscopy is crucial to confirm the nature of the sources and can be used to estimate their redshifts; it will also allow us to test the robustness of our methods when the whole campaign is completed. Here we present the optical spectroscopic observations of 39 sources. Within our sample we found that 6 sources are blazars, candidates to be low-energy counterparts of the UGSs listed in the 2FGL. We confirm that an additional 8 sources, previously classified as active galaxies of uncertain type and associated in the 2FGL, are also all BL Lac objects. Moreover, we also present 20 new spectra for known blazars listed in the Multi-frequency Catalogue of Blazars as having an uncertain redshift and/or being classified as BL Lac candidates. We conclude that our methods for selecting gamma-ray blazar candidates allows us to discover new blazars and increase the list of potential low-energy counterparts for the Fermi UGSs.Comment: 27 pages, 39 figures, 1 table, A&A accepted for publication (pre-proof version

Patrones de utilización del espacio en briozoos epibiontes de la vieira patagónica Psychrochlamys patagonica

We studied the bryozoan assemblage encrusting valves of the Patagonian scallop, Psychrochlamys patagonica, in 4 beds distributed along the continental shelf off Argentina to analyse (a) the distribution pattern of bryozoan colonies in different zones of the valves, (b) the influence of interspecific competition on assemblage composition, (c) whether encrusting species display different space utilisation strategies, and (d) whether bryozoan species richness and number of colonies vary in relation to host size. The assemblage was composed of 22 taxa and was dominated by Arachnopusia monoceros and Osthimosia eatonensis, which were at least one order of magnitude more abundant than any other species. Multivariate analyses based on coverage data of multiserial bryozoans separated the beds according to species richness rather than to geographic proximity and showed significant differences in assemblage structure between upper (left) and lower (right) valves and among beds. Competitive interactions occurred almost exclusively on lower valves, and more frequently in peripheral zones than in central zones of these valves. Correlations between valve area and number of bryozoan colonies, coverage and species richness were low but significant. Bryozoans were significantly more frequent, larger, and taxonomically diverse on lower valves than on upper valves. The uniserial colonies of Neothoa cf. chiloensis, the weakest bryozoan competitor, were as frequent in central zones as they were in peripheral zones, and usually spread out along channels on the scallop surface. This fugitive species was partially covered by multiserial colonies, but managed to persist even in peripheral areas of the lower valves.Se estudiaron los briozoos que incrustan las valvas de Psychrochlamys patagonica en 4 bancos de la plataforma continental argentina para analizar su distribución sobre distintas zonas de las valvas, la influencia de la competencia interespecífica sobre la composición de la asociación, si las especies incrustantes exhiben distintas estrategias de utilización del espacio y si la riqueza específica y abundancia varían en relación al tamaño del huesped. Entre los 22 taxa presentes, Arachnopusia monoceros y Osthimosia eatonensis fueron al menos un orden de magnitud más abundantes que las demás especies. Análisis multivariantes basados en datos de cobertura de briozoos multiseriales separaron a los bancos por su riqueza específica más que por su proximidad geográfica y demostraron diferencias significativas en la estructura de las asociaciones entre valvas superiores (izquierdas) e inferiores (derechas) y entre bancos. Las interacciones competitivas ocurrieron casi exclusivamente sobre valvas inferiores y más frecuentemente en la periferia que en el centro. Las correlaciones entre el área de las valvas y el número de colonias, cobertura y riqueza específica de briozoos fueron bajas pero significativas. Los briozoos fueron más frecuentes, más grandes y más diversificados en las valvas inferiores que en las superiores. Las colonias uniseriales de Neothoa cf. chiloensis, el competidor más débil, fueron tan frecuentes en la zona central como en la periferia, extendiéndose a lo largo de los canales en la superficie de las valvas. Esta especie fugitiva resulta parcialmente cubierta por los briozoos multiseriales, pero logra persistir hasta en la periferia de las valvas inferiores

Lung and chest wall volume during vital capacity manoeuvre in Osteogenesis Imperfecta

Background: Although Osteogenesis Imperfecta (OI) affects the connective tissue, pulmonary function might be compromised because of thoracic deformities. OI is known to be a restrictive lung disease, but spirometry provides global measurement without localizing the site of the restriction. Opto-electronic plethysmography (OEP), is a non-invasive method able to underline altered respiratory function as well as ventilatory thoraco-abdominal paradoxes during spontaneous breathing. We aimed to reconstruct the thoraco-abdominal surface, to perform local analyses of trunk motion and to make quantitative comparison of trunk shape and respiratory kinematics according to OI severity, particularly during maximal inspiratory and expiratory expansions. This is a cross-sectional study where we have studied the thoraco-abdominal compartmental analysis in 26 adult OI patients (14 Type III) at rest and during vital capacity manoeuvre using OEP. We have also applied a new method that created realistic and accurate 3D models to perform local analyses of trunk motion and to make quantitative comparison of trunk shape and respiratory kinematics. Results: Type III patients were characterized by lower spirometric lung volume, by lower sleep quality, by a more compressed thoracic configuration aggravated by severe scoliosis, by reduced global expansion at rest and during maximal maneuvers because of the reduced expansion of the pulmonary ribcage at rest (12% vs. 65% in healthy subjects), during maximal inspiration (37% vs. 69%) and expiration (16% vs. 68%) with local paradoxical movement occurring on the side of the ribcage region. Conclusion: The kinematics of the trunk changed to compensate for the severe structural deformities by shifting the expansion in the abdomen both at rest and during maximal manoeuvre because of a restricted thorax. For the first time, we have quantified and localized the site of the restriction in OI patients in the lateral part of the thorax. The 3D analysis proposed seemed a promising graphical immediate new method for pathophysiology study of chest wall restriction

Improving Bowen-ratio estimates of evaporation using a rejection criterion and multiple-point statistics

The application of the Bowen ratio method to estimate evaporation is heavily affected by uncertainties on the measured quantities. Time series collected with a hydro-meteorological monitoring station often contain measurements for which a reliable estimate of evaporation cannot be computed. Such measurements can be identified with standard error propagation methods. However, simply discarding some values might introduce a bias in the cumulative evaporation for long time intervals, also depending on the threshold of acceptance. In this paper, we propose the use of multiple-point statistics simulation to integrate the time series of reliable evaporation estimates. A test conducted on a two-year-long time series of data collected with a hydro-meteorological station in the Po plain (Italy) shows that the usage of a rejection criteria in conjunction with multiple-point statistics simulation is a promising and useful tool for the reconstruction of reliable evaporation time series. In particular, it is shown that if the rejected values are not replaced by simulation, then the cumulative evaporation curves are estimated with a bias comparable with estimates of cumulative annual evaporation. Moreover, the test gives some insights for the selection of the best rejection threshold