Review on the multiwavelength emission of the gamma-ray binary LS I +61 303

Gamma-ray binaries are systems composed of a massive star and a compact object that produce emission from radio to very high energy gamma-rays. LS I +61 303 is one of the only six gamma-ray binaries discovered so far. It is thought that gamma-ray binaries contain a young highly rotating neutron star as compact object, and the emission is produced by the interaction between its relativistic pulsar wind and the stellar wind, However, in the case of LS I +61 303 a microquasar scenario is still considered and results pointing to oppose directions have been published during the last decades. Here we provide a review about the state of the art of LS I +61 303, summarizing the observed emission from radio to very high energy gamma-rays along all these years, and we discuss the proposed scenarios that can explain such emission.Comment: 9 pages to be published in the proceedings of XII Multifrequency Behaviour of High Energy Cosmic Sources Workshop, Palermo (Italy), PoS(MULTIF2017)04

Localizations of Fast Radio Bursts on milliarcsecond scales

Fast Radio Bursts (FRBs) are transient sources that emit a single radio pulse with a duration of only a few milliseconds. Since the discovery of the first FRB in 2007, tens of similar events have been detected. However, their physical origin remains unclear, and a number of scenarios even larger than the number of known FRBs has been proposed during these years. The presence of repeating bursts in FRB 121102 allowed us to perform a precise localization of the source with the Very Large Array and the European VLBI Network (EVN). Optical observations with Keck, Gemini and HST unveiled the host to be a low-metallicity star-forming dwarf galaxy located at a redshift of 0.193. The EVN results showed that the bursts are co-located (within a projected separation of $< 40$ pc) to a compact and persistent radio source with a size of $< 0.7$ pc inside a star-forming region. This environment resembles the ones where superluminous supernovae (SLSNe) or long gamma-ray bursts are produced. Although the nature of this persistent source and the origin of the bursts remain unknown, scenarios considering a pulsar/magnetar energizing a young SLSN, or a system with a pulsar/magnetar in the vicinity of a massive black hole are the most plausible ones to date. More recent observations have shown that the bursts from FRB 121102 are almost 100% linearly polarized at an unexpectedly high and variable Faraday rotation measure, that has been observed to date only in vicinities of massive black holes. The bursts are thus likely produced from a neutron star in such environment, although the system can still be explained by a young neutron star embedded in a highly magnetized nebula. Upcoming interferometric searches are expected to report tens of these localizations in the coming years, unveil if this source is representative of the whole population or a particular case, and dramatically boosting the field of FRBs.Comment: 11 pages, 3 figures, proceedings of the 14th European VLBI Network Symposium & Users Meeting, held on 8-11 October 2018 in Granada, Spai

Automatic Repair of Infinite Loops

Research on automatic software repair is concerned with the development of systems that automatically detect and repair bugs. One well-known class of bugs is the infinite loop. Every computer programmer or user has, at least once, experienced this type of bug. We state the problem of repairing infinite loops in the context of test-suite based software repair: given a test suite with at least one failing test, generate a patch that makes all test cases pass. Consequently, repairing infinites loop means having at least one test case that hangs by triggering the infinite loop. Our system to automatically repair infinite loops is called $Infinitel$. We develop a technique to manipulate loops so that one can dynamically analyze the number of iterations of loops; decide to interrupt the loop execution; and dynamically examine the state of the loop on a per-iteration basis. Then, in order to synthesize a new loop condition, we encode this set of program states as a code synthesis problem using a technique based on Satisfiability Modulo Theory (SMT). We evaluate our technique on seven seeded-bugs and on seven real-bugs. $Infinitel$ is able to repair all of them, within seconds up to one hour on a standard laptop configuration

Ballroom dance step recognition by means of video processing and Artificial Intelligence techniques.

[Abstract]: Ballroom dancing, or DanceSport is a sport of great complexity due to the number of dance steps that make up every type of dance. This project tries to serve of help to dancers of all levels, both to amateur and professional ones as well as to competition judges in order to evaluate in a more objective manner. To do so, Artificial Intelligence techniques are applied to classify the different dance steps. There were filmed some Rumba choreographies by professional dancers and other videos were collected from external sources. Features from the videos of the datasets are extracted and selected, in terms of body keypoints and movement features for said keypoints to train the models. In order to do so, it is necessary to label all the dance steps in each video, indicating its start and ending times. Thereafter, models are trained with different Artificial Intelligence algorithms, including Multi-Layer Perceptron and Long Short-Term Memory Recurrent Neural Networks, and different feature inputs and parameters. Each model is tested against data from different datasets, such as the custom or the reference dataset. Finally, performance metrics are calculated for each model, and compared against the others.[Resumo]: Baile deportivo ou baile de salón é un deporte de gran complexidade debido ao número de pasos que compoñen cada tipo de baile. Este proxecto trata de servir de axuda a bailaríns de todos os niveis, tanto a principiantes como a profesionais e tamén a xuíces de competición para avaliar de maneira máis obxectiva. Para iso, aplicáronse técnicas de Intelixencia Artificial para clasificar os distintos pasos de baile. Graváronse algunhas coreografías de Rumba bailadas por profesionais e outros vídeos foron recopilados de recursos externos. Se extraen e seleccionan características dos vídeos dos datasets en termos de keypoints do corpo e características de movemento para ditos keypoints para entrenar os modelos. Para poder facer iso, é preciso etiquetar todos os pasos de baile en cada vídeo, indicando o comezo e final. Posteriormente, entrénanse os modelos cos diferentes algoritmos de Intelixencia Artificial, sendo estes Multi-Layer Perceptron e Long Short-Term Memory Recurrent Neural Networks, e diferentes entradas de características e parámetros. Cada modelo é comprobado contra datos de diferentes datasets, como o propio deste proxecto ou o de referencia. Finalmente, se calculan métricas de rendemento para cada modelo, e son comparadas entre elas.Traballo fin de grao (UDC.FIC). Enxeñaría Informática. Curso 2022/202

Paisaxe e arte na poética de Man

El trabajo que se presenta a continuación pretende acercar una memoria, desde la faceta artística, del trabajo de Man. Se busca la reivindicación de su legado en el paisaje de Camelle pero sobre todo su reconocimiento como artista polifacético que consigue combinar escultura, pintura, paisaje, arquitectura y fotografía. En el siguiente documento se exponen datos y citas de expertos en arte como Antón Castro, escritores como Xoán Abeleira, expertos en arquitectura como Xoán Creus, organizadores y partícipes del nuevo museo “Man: mar arte e natureza” como Andrea Serodio y vivencias de los vecinos de la localidad costera, que, en combinación con palabras expresadas por Man, nos hacen llegar una mayor claridad de su pensamiento y de su modo de vida.[Resumo]O traballo que se presenta a continuación pretende achegar unha memoria, dende a faceta artística, do traballo de Man. Procúrase a reivindicación do seu legado na paisaxe de Camelle pero sobre todo o seu recoñecemento como artista polifacético que consegue combiar escultura, pintura, paisaxe, arquitectura e fotografía. No seguinte documento expóñense datos e citas de expertos en arte como Antón Castro, escritores como Xoán Abeleira, expertos en arquitectura como Xoán Creus, organizadores e partícipes do novo museo “Man: mar arte e natureza” como Andrea Serodio, e vivencias dos veciños da localidade costeira, que, en combinación con palabras expresadas por Man, nos fan chegar unha maior claridade do seu pensamento e do seu modo de vida.[Abstract]The work which is presented herewith intends to show a memory, from an artistic point of view, of the work of Man. The vindication of his legacy is sought in the landscape of Camelle, but, above all, his recognition as a multifaceted artist who is able to combine sculpture, painting, landscape, architecture and photography. In the following document, data and quotes from art experts are provided, experts such as Antón Castro, writers such as Xoán Abeleira, architectural experts such as Xoán Creus, organizers and participants of the new museum “Man”; sea, art and nature” such as Andrea Serodio and experiences of the neighbors from the coastal town, which, together with words expressed by Man, give us a clearer insight into his thoughts and way of life.Traballo fin de grao (UDC.ETSA). Estudos en arquitectura. Curso 2015/201

Physical properties of the gamma-ray binary LS 5039 through low and high frequency radio observations

We have studied in detail the 0.15-15 GHz radio spectrum of the gamma-ray binary LS 5039 to look for a possible turnover and absorption mechanisms at low frequencies, and to constrain the physical properties of its emission. We have analysed two archival VLA monitorings, all the available archival GMRT data and a coordinated quasi-simultaneous observational campaign conducted in 2013 with GMRT and WSRT. The data show that the radio emission of LS 5039 is persistent on day, week and year timescales, with a variability $\lesssim 25~\%$ at all frequencies, and no signature of orbital modulation. The obtained spectra reveal a power-law shape with a curvature below 5 GHz and a turnover at $\sim0.5$ GHz, which can be reproduced by a one-zone model with synchrotron self-absorption plus Razin effect. We obtain a coherent picture for a size of the emitting region of $\sim0.85~\mathrm{mas}$, setting a magnetic field of $B\sim20~\mathrm{mG}$, an electron density of $n_{\rm e}\sim4\times10^5~{\rm cm^{-3}}$ and a mass-loss rate of $\dot M\sim5\times10^{-8}~{\rm M_{\odot} yr^{-1}}$. These values imply a significant mixing of the stellar wind with the relativistic plasma outflow from the compact companion. At particular epochs the Razin effect is negligible, implying changes in the injection and the electron density or magnetic field. The Razin effect is reported for first time in a gamma-ray binary, giving further support to the young non-accreting pulsar scenario.Comment: 16 pages, 9 figures, accepted for publication in MNRA

On the k-restricted edge-connectivity of matched sum graphs

A matched sum graph $G_1$M$G_2$ of two graphs $G_1$ and $G_2$ of the same order n is obtained by adding to the union (or sum) of $G_1$ and $G_2$ a set M of n independent edges which join vertices in V ($G_1$) to vertices in V ($G_2$). When $G_1$ and $G_2$ are isomorphic, $G_1$M$G_2$ is just a permutation graph. In this work we derive bounds for the k-restricted edge connectivity λ(k) of matched sum graphs $G_1$M$G_2$ for 2 ≤ k ≤ 5, and present some sufficient conditions for the optimality of λ(k)($G_1$M$G_2$).Peer Reviewe

Towards the origin of the radio emission in AR Sco, the first radio-pulsing white dwarf binary

The binary system AR Sco contains an M star and the only known radio-pulsing white dwarf. The system shows emission from radio to X-rays, likely dominated by synchrotron radiation. The mechanism that produces most of this emission remains unclear. Two competing scenarios have been proposed: Collimated outflows, and direct interaction between the magnetospheres of the white dwarf and the M star. The two proposed scenarios can be tested via very long baseline interferometric radio observations. We conducted a radio observation with the Australian Long Baseline Array (LBA) on 20 Oct 2016 at 8.5 GHz to study the compactness of the radio emission. Simultaneous data with the Australian Telescope Compact Array (ATCA) were also recorded for a direct comparison of the obtained flux densities. AR Sco shows radio emission compact on milliarcsecond angular scales ($\lesssim 0.02\ \mathrm{AU}$, or $4\ \mathrm{R_{\odot}}$). The emission is orbitally modulated, with an average flux density of$\approx 6.5\ \mathrm{mJy}$. A comparison with the simultaneous ATCA data shows that no flux is resolved out on mas scales, implying that the radio emission is produced in this compact region. Additionally, the obtained radio light curves on hour timescales are consistent with the optical light curve. The radio emission in AR Sco is likely produced in the magnetosphere of the M star or the white dwarf, and we see no evidence for a radio outflow or collimated jets significantly contributing to the radio emission.Comment: 4 pages, 2 figures, accepted for publication in A&

La Agenda 21 y la huella ecológica como instrumentos para lograr una universidad sostenible

Para frenar el rápido deterioro ambiental, la universidad ha de formar a las nuevas generaciones en un modelo de sostenibilidad integral (solidaridad sincrónica y diacrónica) y, además, contribuir al cambio en los estilos de vida, en los conocimientos y conductas de la sociedad actual. Esto precisa un nuevo marco teórico-metodológico bajo el paradigma de la sostenibilidad que fundamente y concrete las propuestas educativas. Tomando como referencia los principios del desarrollo sostenible y utilizando como «herramientas» la Agenda 21en la Universidad y la Huella Ecológica, hemos desarrollado y puesto en práctica una estrategia metodológica (ecometodología) con el fin de capacitar a nuestro alumnado (profesorado en formación) para actuar con criterios de sustentabilidad, tanto colectiva, como individualmente.In order to stop the quick environmental deterioration of the planet, University has to prepare the new generations following a model of integral sustainability (synchronic and diachronic solidarity) and it also has to contribute to a change in lifestyles, in knowledge and behaviours in our society. There is a need for a new theoretical-methodological frame under the paradigm of sustainability to base educational proposals on it and to concretize them. Taking into consideration the principles of Sustainable Development and using the tools of «Agenda 21 in the University» and Ecological Footprint, we have developed and applied a methodological strategy (ecomethodology) to enable ours students (future teachers)to act, collectively and individually, according to the criteria of sustainability

Agenda 21 and the ecological footprint as instruments to achieve a sustainable university

[Resumen] Para frenar el rápido deterioro ambiental, la universidad ha de formar a las nuevas generaciones en un modelo de sostenibilidad integral (solidaridad sincrónica y diacrónica) y, además, contribuir al cambio en los estilos de vida, en los conocimientos y conductas de la sociedad actual. Esto precisa un nuevo marco teórico-metodológico bajo el paradigma de la sostenibilidad que fundamente y concrete las propuestas educativas. Tomando como referencia los principios del desarrollo sostenible y utilizando como «herramientas» la Agenda 21en la Universidad y la Huella Ecológica, hemos desarrollado y puesto en práctica una estrategia metodológica (ecometodología) con el fin de capacitar a nuestro alumnado (profesorado en formación) para actuar con criterios de sustentabilidad, tanto colectiva, como individualmente[Abstract] In order to stop the quick environmental deterioration of the planet, University has to prepare the new generations following a model of integral sustainability (synchronic and diachronic solidarity) and it also has to contribute to a change in lifestyles, in knowledge and behaviours in our society. There is a need for a new theoretical-methodological frame under the paradigm of sustainability to base educational proposals on it and to concretize them. Taking into consideration the principles of Sustainable Development and using the tools of «Agenda 21 in the University» and Ecological Footprint, we have developed and applied a methodological strategy (ecomethodology) to enable ours students (future teachers) to act, collectively and individually, according to the criteria of sustainabilit