Connection between orbital modulation of H-alpha and gamma-rays in the Be/X-ray binary LSI+61303

We studied the average orbital modulation of various parameters (gamma-ray flux, H-alpha emission line, optical V band brightness) of the radio- and gamma-ray emitting Be/X-ray binary LSI+61303. Using the Spearman rank correlation test, we found highly significant correlations between the orbital variability of the equivalent width of the blue hump of the H-alpha and Fermi-LAT flux with a Spearman p-value 2e-5, and the equivalent widths ratio EW_B/EW_R and Fermi-LAT flux with p-value 9e-5. We also found a significant anti-correlation between Fermi-LAT flux and V band magnitude with p-value 7.10^{-4}. All these correlations refer to the average orbital variability, and we conclude that the H-alpha and gamma-ray emission processes in LSI+61303 are connected. The possible physical scenario is briefly discussed.Comment: accepted as a Letter in Astronomy and Astrophysic

Short-term volcanic hazard assessment through Bayesian inference: Retrospective application to the Pinatubo 1991 volcanic crisis

© 2014 . One of the most challenging aspects of managing a volcanic crisis is the interpretation of the monitoring data, so as to anticipate to the evolution of the unrest and implement timely mitigation actions. An unrest episode may include different stages or time intervals of increasing activity that may or may not precede a volcanic eruption, depending on the causes of the unrest (magmatic, geothermal or tectonic). Therefore, one of the main goals in monitoring volcanic unrest is to forecast whether or not such increase of activity will end up with an eruption, and if this is the case, how, when, and where this eruption will take place. As an alternative method to expert elicitation for assessing and merging monitoring data and relevant past information, we present a probabilistic method to transform precursory activity into the probability of experiencing a significant variation by the next time interval (i.e. the next step in the unrest), given its preceding evolution, and by further estimating the probability of the occurrence of a particular eruptive scenario combining monitoring and past data. With the 1991 Pinatubo volcanic crisis as a reference, we have developed such a method to assess short-term volcanic hazard using Bayesian inference.This research has been partially funded by the European Commission (FP7 Theme: ENV.2011.1.3.3-1; Grant 282759: VUELCO) and by the Aon Benfield UCL Hazard Centre. All data and information used to reproduce the results in the case study have been extracted from the public source Punongbayan and Newhall (1996) edited monograph on the Mt Pinatubo eruption.Peer Reviewe

Identification of the optical and near-infrared counterpart of GRS 1758-258

Context. Understood to be a microquasar in the Galactic center region, GRS 1758-258 has not yet been unambiguously identified to have an optical/near-infrared counterpart, mainly because of the high absorption and the historic lack of suitable astrometric stars, which led to the use of secondary astrometric solutions. Although it is considered with 1E 1740.7-2942 as the prototypical microquasar in the Galactic center region, the Galactic origin of both sources has not yet been confirmed. Aims. We attempt to improve previous astrometry to identify a candidate counterpart to GRS 1758-258. We present observations with the Gran Telescopio de Canarias (GTC), in which we try to detect any powerful emission lines that would infer an extragalactic origin of this source. Methods. We use modern star catalogues to reanalyze archival images of the GRS 1758-258 field in the optical and near-infrared wavelengths, and compute a new astrometric solution. We also reanalyzed archival radio data of GRS 1758-258 to determine a new and more accurate radio position. Results. Our improved astrometric solution for the GRS 1758-258 field represents a significant advancement on previous works and allows us to identify a single optical/near-infrared source, which we propose as the counterpart of GRS 1758-258. The GTC spectrum of this source is however of low signal-to-noise ratio and does not rule out a Galactic origin. Hence, new spectral observations are required to confirm or discard a Galactic nature.Comment: 4 pages, 3 figures, accepted by Astronomy and Astrophysic

Feature-based matching of underwater images

This work investigates performance of recent feature-based matching techniques when applied to registration of underwater images. Matching methods are tested versus diff erent contrast en¬hancing pre-processing of images. As a result of the performed experiments for various dominat¬ing in images underwater artifacts and present deformation, the outper¬forming preprocessing, detection and description methods are proposed

Quality in action research : reflections for second-order inquiry

One of the current debates in action research concerns the quality of these practices.Up to now, many contributions have focused on defining specific criteria based on action research epistemology. This article sustains (1) that prior to dealing with these questions, it is necessary to define for what purpose and for whom we are making the evaluation; (2) that this leads us to make a distinction between different evaluation models; and (3) that the quality strategies and criteria will be different for each model.In particular, the article confronts an academic evaluation model as a form of external control over the quality of action research and an internal, participatory evaluation model as a quality strategy aimed at establishing feedback for the process. Final considerations are given about the implications of both models for academi

Caront : gestió flexible de grups d'alumnes en una assignatura i activitats sobre grups. Nova activitat de control

L'Espai Europeu d'Educació Superior promociona el plantejament de noves metodologies docents. Davant la demanda de realitzar més avaluacions als estudiants i poder formar grups de treball de forma més flexible, Caront pretén donar aquesta flexibilitat de forma electrónica. Caront permet definir diferents dinàmiques de grups de treball (teoria, pràctiques, problemes, ABP, etc.) on un alumne es pot inscriure en cadascuna d'elles amb companys diferents i entregar els treballs que faci en cada grup de forma diferenciada. En aquest article es presenta una de les principals aportacions de Caront, entorn basat en Moodle: la gestió flexible de grups d'alumnes dins una assignatura universitària. Entenem per grup universitari un conjunt d'alumnes que realitzen un treball, de forma que un d'ells pot fer efectiva l'activitat proposada (entrega, enquesta, etc.) en representació del grup. Un dels punts que hem treballat és en la confecció d'aquests grups. Quan els grups els formen els propis alumnes, apareixen problemes d'intromissió d'un alumne en un grup ja definit. Per evitar això, hem implementat un sistema d'inscripció de grup per contrassenya, que posa el primer que entra, per a compartirla amb els companys que han de formar el grup. Caront ofereix un conjunt d'activitats basades en aquest concepte de grup: enquestes, tasques (entrega de treballs o pràctiques), enquestes d'autoevaluació a nivell de grup i qüestionaris, entre les més importants. Basada en l'activitat de l'enquesta, hem definit una activitat de Control, que permet un cert feedback electrònic del professor sobre l'activitat del grup. Aquesta activitat de control consisteix en una enquesta definida pel professor, amb preguntes que avaluen l'activitat del grup. Així, el professor ha de contestar una enquesta dirigida als alumnes. Les respostes són vistes pels alumnes de forma privada. Finalment, es presenta un resum de les experiències d'us de Caronte sobre un conjunt d'assignatures de les titulacions d'Enginyeria Informàtica en el curs 2006-07, al no disposar encara dels resultats del 2007-08