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PurposeThis article proposes a strategy to make the testing step easier, generating user acceptance tests (UATs) in an automatic way from requirements artifacts.Design/methodology/approachThis strategy is based on two modeling frameworks: scenarios and task/method paradigm. Scenarios are a requirement artifact used to describe business processes and requirements, and task/method paradigm is a modeling paradigm coming from the artificial intelligence field. The proposed strategy is composed of four steps. In the first step, scenarios are described through a semantic wiki website. Then scenarios are automatically translated into a task/method model (step two). In the third step, the task/method model obtained in step two is executed in order to produce and store all possible achievements of tasks and thus scenarios. The stored achievements are saved in a data structure called execution tree (ET). Finally, from this ET (step four), the UATs are generated.FindingsThe feasibility of this strategy is shown through a case study coming from the agriculture production systems field.Originality/valueGenerally, test design approaches deal with a small number of variables describing one specific situation where a decision table or workflow is used to design tests. The proposed approach can deal with many variables because the authors rely on scenarios that can be composed in order to obtain a tree with all the testing paths that can arise from their description.

The PP˙ diagram is a cornerstone of pulsar research. It is used in multiple ways for classifying the population, understanding evolutionary tracks, identifying issues in our theoretical reach, and more. However, we have been looking at the same plot for more than five decades. A fresh appraisal may be healthy. Is the PP˙ -diagram the most useful or complete way to visualize the pulsars we know? Here we pose a fresh look at the information we have on the pulsar population. First, we use principal component analysis over magnitudes depending on the intrinsic pulsar’s timing properties (proxies to relevant physical pulsar features), to analyse whether the information contained by the pulsar’s period and period derivative is enough to describe the variety of the pulsar population. Even when the variables of interest depend on P and P˙⁠, we show that PP˙ are not principal components. Thus, any distance ranking or visualization based only on P and P˙ is potentially misleading. Next, we define and compute a properly normalized distance to measure pulsar nearness, calculate the minimum spanning tree of the population, and discuss possible applications. The pulsar tree hosts information about pulsar similarities that go beyond P and P˙⁠, and are thus naturally difficult to read from the PP˙-diagram. We use this work to introduce the pulsar tree website containing visualization tools and data to allow users to gather information in terms of MST and distance ranking., This work has been supported by the grants PID2021-124581OB-I00 and PGC2018-095512-B-I00. CR is funded by the PhD FPI fellowship PRE2019-090828, and acknowledges the graduate program of the Universitat Autònoma of Barcelona. DFT acknowledges as well USTC and the Chinese Academy of Sciences Presidential Fellowship Initiative 2021VMA0001. AP acknowledges partial support from a Ramon y Cajal fellowship RYC-2017-21810. This work was also supported by the Spanish program Unidad de Excelencia María de Maeztu CEX2020-001058-M.

Collaborative location collecting systems (CLCS) are collaborative systems where users collects location-based data. When these systems are gamified and aim to adapt the game elements to each user, it may require a user traveling behavior profile. This work presents two approaches of traveling user behavior profiling: a raw series built up with categorical data that describes the user's activity in a period, and a timed series that is an enhanced version of the first that includes a representation of the non-activity time frames. The profiling of user traveling behavior can be used in adaptive gamification strategies. The approach is evaluated over a behavioral atoms dataset based on a year of Foursquare check-ins. The results showed that both approaches reflex different aspects of traveling user behavior, and also both could be used in a complementary manner.

The Large-Sized Telescope (LST) prototype of the future Cherenkov Telescope Array (CTA) is located at the Northern site of CTA, on the Canary Island of La Palma. It is designed to provide optimal performance in the lowest part of the energy range covered by CTA, observing gamma rays down to energies of tens of GeV. The LST prototype started performing astronomical observations in November 2019 during the commissioning of the telescope and it has been taking data since then. In this contribution, we will present the tuning of the characteristics of the telescope in the Monte Carlo (MC) simulations to describe the data obtained, the estimation of its angular and energy resolution, and an evaluation of its sensitivity, both with simulations and with observations of the Crab Nebula.

In this work, we introduce the use of the differential geometry Frenet-Serret equations to describe a magnetic line in a pulsar magnetosphere. These equations, which need to be solved numerically, fix the magnetic line in terms of their tangent, normal, and binormal vectors at each position, given assumptions on the radius of curvature and torsion. Once the representation of the magnetic line is defined, we provide the relevant set of transformations between reference frames; the ultimate aim is to express the map of the emission directions in the star co-rotating frame. In this frame, an emission map can be directly read as a light curve seen by observers located at a certain fixed angle with respect to the rotational axis. We provide a detailed step-by-step numerical recipe to obtain the emission map for a given emission process, and give a set of simplified benchmark tests. Key to our approach is that it offers a setting to achieve an effective description of the system's geometry {\it together} with the radiation spectrum. This allows to compute multi-frequency light curves produced by a specific radiation process (and not just geometry) in the pulsar magnetosphere, and intimately relates with averaged observables such as the spectral energy distribution., Comment: Accepted for publication in MNRAS

Understanding the evolution of a supernova remnant shell in time is fundamental. Such understanding is critical to build reliable models of the dynamics of the supernova remnant shell interaction with any pulsar wind nebula it might contain. Here, we perform a large study of the parameter space for the one-dimensional spherically symmetric evolution of a supernova remnant, accompanying it by analytical analysis. Assuming, as is usual, an ejecta density profile with a power-law core and an envelope, and a uniform ambient medium, we provide a set of highly-accurate approximations for the evolution of the main structural features of supernova remnants, such as the reverse and forward shocks and the contact discontinuity. We compare our results with previously adopted approximations, showing that existing simplified prescriptions can easily lead to large errors. In particular, in the context of pulsar wind nebulae modelling, an accurate description for the supernova remnant reverse shock is required. We also study in depth the self-similar solutions for the initial phase of evolution, when the reverse shock propagates through the envelope of the ejecta. Since these self-similar solutions are exact, but not fully analytical, we here provide highly-accurate approximations as well., Comment: 15 pages, 8 figures, 6 tables

Ambrosino, F., et al., Millisecond spinning, low-magnetic-field neutron stars are believed to attain their fast rotation in a 0.1–1-Gyr-long phase during which they accrete matter endowed with angular momentum from a low-mass companion star. Despite extensive searches, coherent periodicities originating from accreting neutron star magnetospheres have been detected only at X-ray energies and in ~10% of the currently known systems. Here we report the detection of optical and ultraviolet coherent pulsations at the X-ray period of the transient low-mass X-ray binary system SAX J1808.4−3658, during an accretion outburst that occurred in August 2019. At the time of the observations, the pulsar was surrounded by an accretion disk, displayed X-ray pulsations and its luminosity was consistent with magnetically funnelled accretion onto the neutron star. Current accretion models fail to account for the luminosity of both optical and ultraviolet pulsations; these are instead more likely to be driven by synchro-curvature radiation in the pulsar magnetosphere or just outside of it. This interpretation would imply that particle acceleration can take place even when mass accretion is going on, and opens up new perspectives in the study of coherent optical/ultraviolet pulsations from fast-spinning accreting neutron stars in low-mass X-ray binary systems., A.M.Z. thanks the HST contact scientist, D. Welty (STScI), for constant support in the observation planning and T. Royle (STScI) for checking the scheduling processes. A.M.Z. thanks A. Riley (STIS Team) for the support in the scientific data analysis. A.M.Z. acknowledges the support of the PHAROS COST Action (CA16214) and A. Ridolfi for his help in data analysis. A.M.Z. would also like to thank G. Benevento for comments on draft. F.C.Z. is supported by a Juan de la Cierva fellowship. S.C. and P.D.A. acknowledge support from ASI grant I/004/11/3. D.d.M., A.P. and L.S. acknowledge financial support from the Italian Space Agency (ASI) and National Institute for Astrophysics (INAF) under agreements ASI-INAF I/037/12/0. L.B., D.d.M., T.D.S., A.P. and L.S. acknowledge financial contributions from ASI-INAF agreement no. 2017-14-H.0, INAF main-stream (principal investigator: T. Belloni; principal investigator: A. De Rosa). D.F.T. acknowledges support from grants PGC2018-095512-B-I00, SGR2017-1383 and AYA2017-92402-EXP. L.B and T.D.S. thank A. Marino for useful discussions and acknowledge financial contributions from the HERMES project financed by the Italian Space Agency (ASI) agreement no. 2016/13 U.O. T.D.S. and L.S. acknowledge the iPeska research grant (principal investigator: A. Possenti) funded under the INAF national call Prin-SKA/CTA approved with the Presidential Decree 70/2016. A.P., F.C.Z., and D.T. acknowledge the International Space Science Institute (ISSI-Beijing), which funded and hosted the international team ‘Understanding and Unifying the Gamma-rays Emitting Scenarios in High Mass and Low Mass X-ray Binaries’.

Knowledge has long been recognised as a valuable asset to individuals, organisations and economy, subsequently knowledge management (KM) has been a well-established area of research. Existing research has developed various classification schemes for knowledge, and a great number of KM process and lifecycle models have been proposed over the last few decades. In particular, knowledge transfer and sharing has received great attention. However, majority of existing work has focused on knowledge sharing within the same organisation or community where people have a shared sense of identity, values and some common practice, hence knowledge process and learning is within relatively homogeneous groups. There is inadequate research to address the issue of knowledge boundaries and approaches to knowledge mobilisation spanning across knowledge boundaries. The knowledge boundaries can erect significant barriers to knowledge sharing and flowing especially in value chain context where there are a great number of players from different domains, with varied level of knowledge, having different and possibly conflicting interests - participating in knowledge sharing activities. This paper will explore how such knowledge boundaries can be identified and how knowledge gaps among different value chain players can be closed by using appropriate boundary-crossing mechanisms. A multi-perspective knowledge mobilisation framework is proposed. Example applications of the knowledge mobilisation framework in agri-food value chain will be illustrated, based on the most recent developments from an EU collaborative project, RUC-APS (standing for Risk and Uncertain Conditions in Agriculture Production Systems), which is funded by European Commission’s Horizon 2020 RISE programme., Laboratorio de Investigación y Formación en Informática Avanzada

Gamification can be used to foster participation in knowledge sharing communities. While designing and assessing the potential impact of a gamification design in such a context, it is important to avoid work disruption and negative side effects. A gamification optimization approach implemented with deep reinforcement learning based on play-testing approaches helps prevent possible disruptive configuration and has the capability to adapt to different communities or gamification targets. In this research, a case of study for this approach is presented running over the Stack Overflow Q&A community. The approach detects the best configuration for a Contribution, Reinforcement, and Dissemination (CRD) gamification strategy using Stack Overflow historical data in a year. The results show that the approach funds proper gamification strategy configurations. Moreover, those configurations are robust enough to be applied along the time unseen periods.

espanolActualmente, el juego es analizado como un elemento importante para motivar la interaccion de usuarios en diferentes tipos de entornos. Este analisis ha derivado en promover diferentes estrategias para adaptar elementos propios de los juegos y los videojuegos en contextos que no estan disenados como tal, pero en los que se busca estimular la participacion de los usuarios. Una estrategia al aplicar elementos de juego es considerar un modelo centrado en la experiencia del usuario. Sin embargo, para establecer un diseno de juego en contextos en donde prevalece el aspecto colaborativo, se requiere abordar estrategias especificas centradas en su relacion con la comunidad a la que pertenece. Este articulo presenta el diseno de un entorno ludificado basado en el marco conceptual G.A.M.E. acronimo de recopilacion, analisis, modelado y ejecucion (gathering, analysis, modeling and execution), aplicado a una comunidad de construccion colaborativa de conocimiento sobre Buenas Practicas Horticolas, complementado, ademas, con una interfaz fisica. EnglishCurrently, the game is analyzed as an important element to motivate the interaction of users in different types of environments. This analysis has resulted in promoting different strategies to adapt elements of games and video games in contexts that are not designed as such, but in which it seeks to stimulate the participation of users. One strategy when applying game elements is to consider a user experience-centric model. However, to establish a game design in contexts where the collaborative aspect prevails, it is necessary to address specific strategies focused on your relationship with the community to which you belong. This article introduces the design of a gaded environment based on the G.A.M.E. conceptual framework for gathering, analysis, modeling, and execution, applied to a collaborative building community of knowledge of Good Horticultural Practices, complemented by a physical interface portuguesAtualmente, o jogo e analisado como um elemento importante para motivar a interacao dos usuarios em diferentes tipos de ambientes. Essa analise resultou na promocao de diferentes estrategias para adaptar elementos de jogos e videogames em contextos que nao sao desenhados como tal, mas nos quais busca estimular a participacao dos usuarios. Uma estrategia na aplicacao de elementos de jogo e considerar um modelo centrado na experiencia do usuario. No entanto, para estabelecer um design de jogo em contextos onde o aspecto colaborativo prevalece, e necessario abordar estrategias especificas focadas em seu relacionamento com a comunidade a qual voce pertence. Este artigo introduz o desenho de um ambiente gaded baseado no quadro conceitual G.A.M.E. para coleta, analise, modelagem e execucao, (gathering, analysis, modeling and execution) aplicado a uma comunidade de construcao colaborativa de conhecimento de Boas Praticas Horticulturais, complementado por uma interface fisica.

With the aim of pushing innovation through information and communication technology in the agri-business field, working closely with farmers is essential. It is especially important to systematically capture their knowledge in order to analyze, propose and design innovation artifacts (in terms of software applications). In this article, we use Scenarios to capture the knowledge of the experts that is elicited in early meetings previous to the definition of requirements. At those early stages, there are many uncertainties, and we are particularly interested in decision support. Thus, we propose an extension of the Scenarios for dealing with uncertainties. Scenarios are described in natural language, and it is very important to have an unbiased vocabulary. We complement Scenarios with a specific glossary, the Language Extended Lexicon that is also extended to decision support. According to V-model life cycle, every stage has a testing related stage. Thus, we also propose a set of rules to derive tests from the Scenarios. Summing up, we propose (i) an extension to Scenarios and the Language Extended Lexicon templates, (ii) a set of rules to derive tests, and (iii) an application to support the proposed technique. We have applied the proposed approach in a couple of case studies and we are confident that the results are promising. Nevertheless, we need to perform a further exhaustive validation. Laboratorio de Investigación y Formación en Informática Avanzada

Identification and characterization of a rapidly increasing number of pulsar wind nebulae is, and will continue to be, a challenge of high-energy gamma-ray astrophysics. Given that such systems constitute -- by far -- the most numerous expected population in the TeV regime, such characterization is important not only to learn about the sources per se from an individual and population perspective, but also to be able to connect them with observations at other frequencies, especially in radio and X-rays. Also, we need to remove the emission from nebulae in highly confused regions of the sky for revealing other underlying emitters. In this paper we present a new approach for theoretical modelling of pulsar wind nebulae: a hybrid hydrodynamic-radiative model able to reproduce morphological features and spectra of the sources, with relatively limited numerical cost., Comment: 15 pages, 9 figures

Insight-HXMT is the first Chinese X-ray astronomical mission, launched successfully on June 15, 2017, from China's Jiuquan Satellite Launch Center. Insight-HXMT was designed to have a broad energy coverage in X-rays, from 1-250 keV, with excellent timing and adequate energy resolution at soft X-rays, and the largest effective area at hard X-rays. Here, we present a collection of papers of the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite Insight-HXMT. These papers cover the in-orbit performance, the background model, and all calibration results, together with several first results on observations of binaries and details on the Galactic plane survey., Comment: Published to introduce a set of 20+ papers from the HXMT collaboration. Most of the referred papers can be accessed in astro-ph already, and all will be avaialble from JHEAp's webpage too, at https://www.sciencedirect.com/journal/journal-of-high-energy-astrophysics/special-issue/10B0FLKPH6C

The Pierre Auger collaboration has provided a compelling indication for a possible correlation between the arrival directions of ultrahigh-energy cosmic rays and nearby starburst galaxies. Herein we show how the latest large-scale modeling of starburst galaxies is compatible with the cosmic rays producing the anisotropy signal being accelerated at the terminal shock of superwinds., The research of L. A. A. is supported by the U.S. National Science Foundation (NSF Grant No. PHY-1620661) and the National Aeronautics and Space Administration (NASA Grant No. 80NSSC18K0464). The research of D. F. T. is supported by Grants No. PGC2018-095512-BI00, No. AYA2017-92402-EXP, and No. SGR 2017-1383.

We report on the first NuSTAR observation of the transitional millisecond pulsar binary XSS J12270-4859 during its current rotation-powered state, complemented with a 2.5 yr-long radio monitoring at Parkes telescope and archival XMM-Newton and Swift X-ray and optical data. The radio pulsar is mainly detected at 1.4 GHz displaying eclipses over ∼ 40 per cent of the 6.91 h orbital cycle. We derive a new updated radio ephemeris to study the 3- 79 keV light curve that displays a significant orbital modulation with fractional amplitude of 28 ± 3 per cent, a structured maximum centred at the inferior conjunction of the pulsar and no cycle-to-cycle or low-high-flaring mode variabilities. The average X-ray spectrum, extending up to ∼70 keV without a spectral break, is well described by a simple power law with photon index γ = 1.17 ± 0.08 giving a 3-79 keV luminosity of 7.6+3.8 -0.8 × 1032 erg s-1 for a distance of 1.37+0.69 -0.15 kpc. Energy resolved orbital light curves reveal that the modulation is not energy dependent from 3 to 25 keV and is undetected with an upper limit of ∼10 per cent above 25 keV. Comparison with previous X-ray XMM-Newton observations in common energy ranges confirms that themodulation amplitudes vary on time-scales of a fewmonths, indicative of a non-stationary contribution of the intrabinary shock (IBS) formed by the colliding winds of the pulsar and the companion. A more detailed inspection of energy resolved modulations than previously reported gives hints of a mild softening at superior conjunction of the pulsar below 3 keV, likely due to the contribution of the thermal emission from the neutron star. The IBS emission, if extending into the MeV range, would be energetically capable alone to irradiate the donor star., DdM, AP, and TMB acknowledge financial support from the Italian Space Agency (ASI) and National Institute for Astrophysics (INAF) under agreements ASI-INAF I/037/12/0 and ASI-INAF n.2017-14-H.0 and from INAF ‘Sostegno alla ricerca scientifica main streams dell’INAF’, Presidential Decree 43/2018. DdM, AP, MB, and AP also acknowledge support from INAF ‘SKA/CTA projects’, Presidential Decree 70/2016. DFT acknowledges support from the Spanish Ministry of Economy, Industry and Competitiveness grants PGC2018-095512-B-I00, SGR2017-1383, and AYA2017-92402-EXP. FCZ is supported by a Juan de la Cierva fellowship and grants from the Spanish Ministry of Economy, Industry and Comeptitiveness grants SGR2017-1383 and PGC2018-095512-B-I00. We also thank the ‘PHAROS’ COST Action (CA16214) for partial support.

The gamma-ray binary HESS J0632+057 has been observed at very-high energies (E $>$ 100 GeV) for more than ten years by the major systems of imaging atmospheric Cherenkov telescopes. We present a summary of results obtained with the H.E.S.S., MAGIC, and VERITAS experiments based on roughly 440 h of observations in total. This includes a discussion of an unusually bright TeV outburst of HESS J0632+057 in January 2018. The updated gamma-ray light curve now covers all phases of the orbital period with significant detections in almost all orbital phases. Results are discussed in context with simultaneous observations with the X-ray Telescope onboard the Neil Gehrels Swift Observatory., Proceedings of the 36th International Cosmic Ray Conference (ICRC2019) Madison, WI July 24-Aug 1, 2019

Organizations produce and exchange a huge amount of critical information, which main purpose is to obtain acceptable results. Hence, the trend is by considering integrated systems that can be easily adapted to several domains, especially when they need to exchange information. In this context, the agribusiness sector is a good example where massive data is generated, which implies the need for information sharing and collaboration, where the great challenged is support and understand the colliding context. However, every software system relies on its context, with its own rules, dynamism, and languages. Hence, it implies a significant effort to have a complete understanding of the composed domain. For this purpose, scenarios are well-known tools to describe dynamic domains and are commonly described under text-based context. When different stakeholders build Scenarios, it is essential to review them in order to unify their description. Thus, Scenarios under this unified perspective will better support the analysis and identification of relationship between two or more domains. This analysis is the key to design mechanisms to exchange information. Therefore, in the light of this, this paper proposes a semantic definition of Scenarios and a set of queries to identify issues in the Scenarios and improve their quality. In addition to this, a wiki platform to implement the semantic support and the queries is also provided.

We report on a multi-wavelength study of the unclassified X-ray source CXOU J110926.4-650224 (J1109). We identified the optical counterpart as a blue star with a magnitude of $\sim$20.1 (3300-10500 $\require{mediawiki-texvc} \AA$). The optical emission was variable on timescales from hundreds to thousands of seconds. The spectrum showed prominent emission lines with variable profiles at different epochs. Simultaneous XMM-Newton and NuSTAR observations revealed a bimodal distribution of the X-ray count rates on timescales as short as tens of seconds, as well as sporadic flaring activity. The average broad-band (0.3-79 keV) spectrum was adequately described by an absorbed power law model with photon index of $\Gamma$=1.63$\pm$0.01 (at 1$\sigma$ c.l.), and the X-ray luminosity was (2.16$\pm$0.04)$\times$10$^{34}$ erg s$^{-1}$ for a distance of 4 kpc. Based on observations with different instruments, the X-ray luminosity has remained relatively steady over the past $\sim$15 years. J1109 is spatially associated with the gamma-ray source FL8Y J1109.8-6500, which was detected with Fermi at an average luminosity of (1.5$\pm$0.2)$\times$10$^{34}$ erg s$^{-1}$ (assuming the distance of J1109) over the 0.1-300 GeV energy band between 2008 and 2016. The source was undetected during ATCA radio observations that were simultaneous with NuSTAR, down to a 3$\sigma$ flux upper limit of 18 $\mu$Jy/beam (at 7.25 GHz). We show that the phenomenological properties of J1109 point to a binary transitional pulsar candidate currently in a sub-luminous accretion disk state, and that the upper limits derived for the radio emission are consistent with the expected radio luminosity for accreting neutron stars at similar X-ray luminosities., Comment: 21 pages, 15 figures, accepted for publication in A&A

The Cherenkov Telescope Array (CTA) will be the next generation instrument for the very high energy gamma-ray astrophysics domain. With its enhanced sensitivity in comparison with the current facilities, CTA is expected to shed light on a varied population of sources. In particular, we will achieve a deeper knowledge of the Crab nebula and pulsar, which are the best characterized pulsar wind nebula and rotation powered pulsar, respectively. We aim at studying the capabilities of CTA regarding these objects through simulations, using the main tools currently in development for the CTA future data analysis: Gammapy and ctools. We conclude that, even using conservative Instrument Response Functions, CTA will be able to resolve many uncertainties regarding the spectrum and morphology of the pulsar and its nebula. The large energy range covered by CTA will allow us to disentangle the nebula spectral shape among different hypotheses, corresponding to different underlying emitting mechanisms. In addition, resolving internal structures (smaller than ~ 0.02 degrees in size) in the nebula and unveiling their location, would provide crucial information about the propagation of particles in the magnetized medium. We used a theoretical asymmetric model to characterise the morphology of the nebula and we showed that if predictions of such morphology exist, for instance as a result of hydrodynamical or magneto-hydrodynamical simulations, it can be directly compared with CTA results. We also tested the capability of CTA to detect periodic radiation from the Crab pulsar obtaining a precise measurement of different light curves shapes., Comment: in press in MNRAS

La pandemia COVID-19 ha provocado cambios profundos en toda la sociedad. A partir de las medidas de aislamiento adoptadas, todo el sistema educativo basado fundamentalmente en la modalidad presencial, se ha visto obligado a sostener el proceso de enseñanza y aprendizaje de forma virtual. Sin embargo, la mayoría de los profesores no estaban preparados para este cambio tan brusco. Muchos tuvieron que adquirir conocimientos sobre el uso de tecnologías y enfoques pedagógicos para llevar adelante sus actividades, aumentando aún más su carga laboral. En este contexto, se han sumado además, otras tareas vinculadas a la atención del hogar y al cuidado de familiares a cargo.. En este contexto, este artículo muestra los resultados de una investigación realizada con profesores universitarios argentinos, cuyo objetivo fue comprender los factores de estrés relacionados con los cambios abruptos llevados a cabo en sus prácticas docentes como resultado de la pandemia. Los resultados obtenidos muestran un aumento significativo en la percepción de estrés en pandemia, una alta tasa de dificultades en el uso de herramientas tecnológicas para pasar de clases presenciales a virtuales, a pesar que la mayoría de las personas encuestadas poseen conocimientos informáticos. The COVID-19 pandemic has caused profound changes throughout society. Because of the isolation measures adopted, the entire educational system based mainly on the face-to-face modality, has been forced to continue the teaching and learning process virtually. However, most of the teachers were not prepared for this abrupt change. Many had to acquire knowledge about the use of technologies and pedagogical approaches to carry out their activities, with a further increase of their workload. In this pandemic situation, other tasks related to home care and care of dependents have also been added. In this context, this article shows the results of an investigation carried out with Argentine university professors, whose objective was to understand the stress factors related to the abrupt changes in their teaching practices as a result of the pandemic's conditions. The results we obtained show a significant increase in the perception of stress in the work conditions under pandemic and a high rate of difficulties in the use of technological tools and methodologies, to go from face-to-face to virtual classes, despite the fact that most of the people surveyed have computer skills.

ANONYMOUS PROJECT is an international project run by 16 research institutions. The project's main goal is empowering agriculture production systems through innovative knowledge-based ICT solutions to deal with high risk and uncertain conditions. In this context, a Semantic Mediawiki is desired to support the various stakeholders in the agriculture value chain in the task of capturing and sharing agricultural best practices. Applying gamification to Wikis is one strategy to encourage the community to participate, and It could be achieved by attaching Metagame, a gamification layer system. However, It could be risky because the tunning of a gamification system in the production face of the wiki could be perceived by the users as a bug in the system. To avoid this situation, a simulation based on the real historical data of the Agriculture community in Wikipedia from 2001 to 2018 was performed. The simulation revealed that is not obvious to generate a system of awards on the type of actions carried out by the Wikipedia editors. The construction of knowledge is done in very small portions, and some of them can be confused with improvements or corrections instead of contributions. Indeed, It shows the importance of tuning the reward parameters, because that allows advancing in the Metagame rank evolution.

We thoroughly study the photo-disintegration of $^{4}\mathrm{He}$ on the cosmic microwave background using the most recent cross-section data from both the inclusive measurement observing the analog of the giant dipole resonance in $^{4}\mathrm{He}$ through the charge-exchange spin-flip $^{4}\mathrm{He}$ ($^{7}\mathrm{Li},^{7}\mathrm{Be}$) reaction and from measurements of exclusive two-body and three-body processes: $^{4}\mathrm{He}(\ensuremath{\gamma},p)\text{ }^{3}\mathrm{H}$, $^{4}\mathrm{He}(\ensuremath{\gamma},n)\text{ }^{3}\mathrm{He}$, and $^{4}\mathrm{He}(\ensuremath{\gamma},pn)\text{ }^{2}\mathrm{H}$. We show that the present-day (redshift $z=0$) mean-free path of ultrarelativistic (Lorentz factor $\ensuremath{\sim}{10}^{10}$) helium nuclei increases by more that 15% with respect to previous estimates adopted as benchmarks for Monte Carlo simulation codes of ultrahigh-energy cosmic ray propagation. This implies that the physical survival probability of $^{4}\mathrm{He}$ nuclei would be larger than predicted by existing event generators. For example, for $E\ensuremath{\sim}1{0}^{10.8}\text{ }\text{ }\mathrm{GeV}$ and a propagation distance of 3.5 Mpc, the $^{4}\mathrm{He}$ intensity would be 35% larger than the output of the CRPropa 3 program and 42% larger than the output of the SimProp v2r4 program. We provide new parametrizations for the two-body and three-body photo-disintegration cross sections of $^{4}\mathrm{He}$, $^{3}\mathrm{He}$, tritium, and deuterium.

Efficient scheduling of astronomical surveys is a challenge with an increasing level of complexity as the observation strategies are becoming more sophisticated and operational costs are higher. In general, any kind of astronomical survey requires the execution of a huge number of observations fulfilling several constraints. The fulfillment and optimization of these constraints is a key factor for obtaining an efficient schedule with an adequate exploitation of the resources and with a high scientific return. In this contribution, we present the framework STARS (Scheduling Telescopes as Autonomous Robotic Systems) that computes optimal schedules for a variety of space- and ground-based infrastructures and scientific exploitation plans. STARS provides methods, tools and libraries for the definition of surveys (e.g., objects to observe, features of the objects, observation constraints), the definition of the observatories (e.g., location, number of telescopes, type of telescopes, sub-array configurations), the usage of astronomical calculations (e.g., object coordinates, object elevation, Sun and Moon position, Moon phase), and the application of schedulers (e.g., long-term, short-term) based on Genetic Algorithms (GAs) and astronomy-based heuristics. In STARS, two main types of schedulers are defined: long-term and short-term. The long-term scheduler is focused on scheduling object observations with a time scope ranging from one night to several months or years. It considers the observation constraints (hard-constraints) that can be predicted beforehand, and it optimizes some objectives (soft constraints) by using GAs. The execution of the long-term scheduler can be time-expensive, but it is not time-critical because it can be run before the start of the telescope operation, so it can be used as a standalone scheduling tool. On the other hand, the short-term scheduler computes in real-time the next observation (or scheduling block) to be executed by optimizing some soft constraints, fulfilling all the hard constraints and by considering all the observations previously executed. The short-term scheduler is time-critical and reacts in less than a second to the changing conditions (weather, errors, delays, targets of opportunity). It uses astronomy-based heuristics to repair the schedule obtained by the long-term scheduler, in order to keep the long-term perspective while avoiding intensive calculations. STARS has been successfully applied in several ground and space-based observatories. It is used to operate the CARMENES instrument (Calar Alto, carmenes.caha.es) and the Joan Oro robotic Telescope (www.oadm.cat). It is used to prototype the mission planning tool for the ARIEL M4-ESA candidate mission, and in prototypes for large ground-based installations, such i.e. the Cherenkov Telescope Array (CTA). Finally, STARS is also being extended to cover multi-observatory coordinated scheduling purposes, under the framework of the EU-H2020 ASTERICS project, and in order to promote multi-messenger science. The coordination of large observatories in the northern and southern hemispheres are used as test cases to evaluate the performance of such an innovative scheduling solution. In this sense, simultaneous observations or minimal time gap between observations are promoted resulting in a challenging and complex optimization problem that will open a new era for the optimal operation of large astrophysical infrastructures.

Publisher's version (útgefin grein)., We use joint observations by the Swift X-ray Telescope (XRT) and the Fermi Large Area Telescope (LAT) of gamma-ray burst (GRB) afterglows to investigate the nature of the long-lived high-energy emission observed by Fermi LAT. Joint broadband spectral modeling of XRT and LAT data reveals that LAT nondetections of bright X-ray afterglows are consistent with a cooling break in the inferred electron synchrotron spectrum below the LAT and/or XRT energy ranges. Such a break is sufficient to suppress the high-energy emission so as to be below the LAT detection threshold. By contrast, LAT-detected bursts are best fit by a synchrotron spectrum with a cooling break that lies either between or above the XRT and LAT energy ranges. We speculate that the primary difference between GRBs with LAT afterglow detections and the nondetected population may be in the type of circumstellar environment in which these bursts occur, with late-time LAT detections preferentially selecting GRBs that occur in low wind-like circumburst density profiles. Furthermore, we find no evidence of high-energy emission in the LATdetected population significantly in excess of the flux expected from the electron synchrotron spectrum fit to the observed X-ray emission. The lack of excess emission at high energies could be due to a shocked external medium in which the energy density in the magnetic field is stronger than or comparable to that of the relativistic electrons behind the shock, precluding the production of a dominant synchrotron self-Compton (SSC) component in the LAT energy range. Alternatively, the peak of the SSC emission could be beyond the 0.1–100 GeV energy range considered for this analysis., Funding text #1 46 Funded by contract FIRB-2012-RBFR12PM1F from the Italian Ministry of Education, University and Research (MIUR). 47 https://fermi.gsfc.nasa.gov/ssc/observations/types/grbs/lat_grbs/ Funding text #2 The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT, as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States; the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France; the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy; the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK), and Japan Aerospace Exploration Agency (JAXA) in Japan; and the K.A.Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Funding text #3 Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515.

International audience; CODALEMA is one of the pioneer experiments dedicated to the radio detection of ultra high energy cosmic rays (UHECR), located at the radio observatory of Nançay (France). The CODALEMA experiment uses both a particle detector array and a radio antenna array. Data from both detection systems have been used to determine the ground coordinates of the core of extensive air showers (EAS). We discuss the observed systematic shift of the core positions determined with these two detection techniques. We show that this shift is due to the charge-excess contribution to the total radio emission of air showers, using the simulation code SELFAS. The dependences of the radio core shift to the primary cosmic ray characteristics are studied in details. The observation of this systematic shift can be considered as an experimental signature of the charge excess contribution.

A large fraction of Galactic very-high energy (VHE; E$\gtrsim$100 GeV) $\gamma$-ray sources is cataloged as unidentified. In this work we explore the possibility that these unidentified sources are located in ambients particularly rich in material content unaccounted by traditional tracers. In a scenario where the VHE emission is due to the interaction of the accelerated particles with a target mass, a large mass of untraced material could be substantially contributing to the VHE emission from these regions. Here, we use three tracers for the commonly explored components: intensity of the $^\textrm{12}$CO(1$\rightarrow$0) line to trace the molecular material, HI hyperfine transition at 21cm to trace atomic hydrogen, and dust emission to trace the total hydrogen content. We show that the estimates of material content from these three tracers are compatible if the uncertainty on the respective conversion factors is taken into account. No additional gas component is found in these regions. However, a simple mass estimation from the $^\textrm{12}$CO(1$\rightarrow$0) line intensity might underestimate the total mass component in some locations., Comment: 9 pages, 4 figures, accepted for publication in JHEAP

We present the first detection of X-ray coherent pulsations from the transitional millisecond pulsar XSS J12270-4859, while it was in a sub-luminous accretion disk state characterized by a 0.5-10 keV luminosity of 5E33 erg/s (assuming a distance of 1.4 kpc). Pulsations were observed by XMM-Newton at an rms amplitude of (7.7 +/- 0.5)% with a second harmonic stronger than the the fundamental frequency, and were detected when the source is neither flaring nor dipping. The most likely interpretation of this detection is that matter from the accretion disk was channelled by the neutron star magnetosphere and accreted onto its polar caps. According to standard disk accretion theory, for pulsations to be observed the mass in-flow rate in the disk was likely larger than the amount of plasma actually reaching the neutron star surface; an outflow launched by the fast rotating magnetosphere then probably took place, in agreement with the observed broad-band spectral energy distribution. We also report about the non-detection of X-ray pulsations during a recent observation performed while the source behaved as a rotationally-powered radio pulsar., Accepted for publication in MNRAS Letters. 5 pages, including 3 figures and 1 table. Corrected a typo in the uncertainty affecting the spin frequency

One of the most important predictions of any gap model for pulsar magnetospheres is the predicted $\gamma$-ray spectra. In the outer gap model, the properties of the synchro-curvature radiation are sensitive to many parameters, whose realistic ranges have been studied in detail in an accompanying paper. There we demonstrated that the uncertainty in the radius of curvature, the magnetic field geometry, and the X-ray surface flux may affect by orders of magnitude the predicted flux and spectral peak in the $\gamma$-ray regime. Here, we present a systematic, numerical study of the impact of the different parameters on the particle dynamics along the gap and calculate the emitted synchro-curvature radiation along the trajectory. By integrating the emitted radiation along the gap and convolving it with a parametrized particle distribution, we discuss how the comparison with the wealth of {\em Fermi}-LAT data can be used to constrain the applicability of the model. The resulting spectra show very different energy peaks, fluxes and shapes, qualitatively matching the great variety of the observed {\em Fermi}-LAT pulsars. In particular, if we see a large fraction of photons emitted from the initial part of the trajectory, we show that the spectra will be flatter at the low-energy {\it Fermi}-LAT regime (100 MeV -- 1 GeV). This provides a solution for such observed flat spectra, while still maintain synchro-curvature radiation as the origin of these photons., Comment: 9 pages, 6 figures, 1 table. Accepted for pubblication in MNRAS main journal. References updated

We report on the results of the extensive multi-wavelength campaign from optical to GeV gamma-rays of the 2014 periastron passage of PSR B1259-63, which is a unique high-mass gamma-ray emitting binary system with a young pulsar companion. Observations demonstrate the stable nature of the post-periastron GeV flare and prove the coincidence of the flare with the start of rapid decay of the H$\alpha$ equivalent width, usually interpreted as a disruption of the Be stellar disk. Intensive X-ray observations reveal changes in the X-ray spectral behaviour happening at the moment of the GeV flare. We demonstrate that these changes can be naturally explained as a result of synchrotron cooling of monoenergetic relativistic electrons injected into the system during the GeV flare., Comment: 13 pages, submitted to MNRAS

We consider the fundamental problem of charged particles moving along and around a curved magnetic field line, revising the synchro-curvature radiation formulae introduced by Cheng and Zhang (1996). We provide more compact expressions to evaluate the spectrum emitted by a single particle, identifying the key parameter that controls the transition between the curvature-dominated and the synchrotron-dominated regime. This parameter depends on the local radius of curvature of the magnetic field line, the gyration radius, and the pitch angle. We numerically solve the equations of motion for the emitting particle by considering self-consistently the radiative losses, and provide the radiated spectrum produced by a particle when an electric acceleration is balanced by its radiative losses, as it is assumed to happen in the outer gaps of pulsar's magnetospheres. We compute the average spectrum radiated throughout the particle trajectory finding that the slope of the spectrum before the peak depends on the location and size of the emission region. We show how this effect could then lead to a variety of synchro-curvature spectra. Our results reinforce the idea that the purely synchrotron or curvature losses are, in general, inadequate to describe the radiative reaction on the particle motion, and the spectrum of emitted photons. Finally, we discuss the applicability of these calculations to different astrophysical scenarios., 9 pages, 5 figures, 2 tables. Accepted for publication in MNRAS main journal. References updated

According to the Convention on the Rights of Persons with Disabilities promoted by United Nations, States should provide Effective individualized support measures are provided in environments that maximize academic and social development, consistent with the goal of full inclusion”. However, subjects at universities have not a production of their contents accessible for people with disabilities. This article introduces the experience in adapting the content of an object-oriented programming course to be accessible for a blind student. The experience details the work done in the generation of support material, the format adaptation in lectures, and the search of tools for blind people to generate UML diagrams.

Wikipedia is a knowledge building community that lets anyone create and edit articles. While editing articles, users employ visual structure elements (VSE) to format content. VSEs are part of the Wikipedia markup language. All creation and editing events are recorded in a revision history. An unsupervised learning approach was used to analyze a dataset with more than 2,000,000 revisions of 126,000 articles. Using K-Means clustering and association rules mining a general classification of revisions was derived. Relevant classes include vandalism revisions, correction revisions and common revisions. Each class was later studied, and patterns of usage of markups elements identified. Those results help to identify the user intention, and the knowledge of VSE use could contribute to improving the actual text editors provide by Wikipedia to improve the editor's activity finally.

HESS J0632+057 is the only gamma-ray binary that has been detected at TeV energies, but not at GeV energies yet. Based on nearly nine years of Fermi Large Area Telescope (LAT) Pass 8 data, we report here on a deep search for the gamma-ray emission from HESS J0632+057 in the 0.1-300 GeV energy range. We find a previously unknown gamma-ray source, Fermi J0632.6+0548, spatially coincident with HESS J0632+057. The measured flux of Fermi J0632.6+0548 is consistent with the previous flux upper limit on HESS J0632+057 and shows variability that can be related to the HESS J0632+057 orbital phase. We propose that Fermi J0632.6+0548 is the GeV counterpart of HESS J0632+057. Considering the Very High Energy (VHE) spectrum of HESS J0632+057, a possible spectral turnover above 10 GeV may exist in Fermi J0632.6+0548, as appears to be common in other established gamma-ray binaries., Comment: 17 pages, 4 figures, 1 table; Accepted for publication in ApJ

The microquasar Cygnus X-1 displays the two typical soft and hard X-ray states of a black hole transient. During the latter, Cygnus X-1 shows a one-sided relativistic radio-jet. Recent detection of the system in the high energy (HE; E greater than or similar to 60 MeV) gamma-ray range with FermiLAT associates this emission with the outflow. Former MAGIC observations revealed a hint of flaring activity in the very high-energy (VHE; E greater than or similar to 100 GeV) regime during this X-ray state. We analyse ~ to 97 h of Cygnus X-1 data taken with the MAGIC telescopes between July 2007 and October 2014. To shed light on the correlation between hard X-ray and VHE gamma rays as previously suggested, we study each main X-ray state separately. We perform an orbital phase-folded analysis to look for variability in the VHE band. Additionally, to place this variability behaviour in a multiwavelength context, we compare our results with Fermi-LAT, AGILE, Swift-BAT, MAXI, RXTE-ASM, AMI and RATAN-600 data. We do not detect Cygnus X-1 in the VHE regime. We establish upper limits for each X-ray state, assuming a power-law distribution with photon index Γ = 3.2. For steady emission in the hard and soft X-ray states, we set integral upper limits at 95 %per cent confidence level for energies above 200 GeV at 2.6 x 10⁻¹² photons cm⁻² s⁻¹ and 1.0 x 10⁻¹¹ photons cm⁻² s ⁻¹, respectively. We rule out steady VHE gamma-ray emission above this energy range, at the level of theMAGIC sensitivity, originating in the interaction between the relativistic jet and the surrounding medium, while the emission above this flux level produced inside the binary still remains a valid possibility.

In this article, we discuss existing literature on DSS in agriculture, on DSS that use data available in the Semantic Web, and on Semantic Web initiatives focusing on agriculture information. Our goal is to assess the readiness of the Semantic Web as a platform to empower DSS that can keep risk and uncertainty in agriculture under control. Key agricultural activities targeted by DSS reported in literature are nutrient management, insect and pest management, land use and planning, environmental change and forecasting, and water and drought management. The most relevant use of Semantic Web in DSS, is in data analysis, as a means of making DSS more intelligent. There are initiatives to produce vocabularies and semantic repositories in the domain of agriculture. However, data and models are still isolated in specific domain repositories, and interoperability is still weak.

The positron flux measured near Earth shows a rise with energy beyond 30 GeV. We show that this rise may be compatible with the production of positrons in $p \gamma$ interactions in the jets of microquasars., Comment: 5 pages, 1 figure, to be published in MNRAS

Indications of a GeV component in the emission from GRBs are known since the EGRET observations during the 1990's and they have been confirmed by the data of the Fermi satellite. These results have, however, shown that our understanding of GRB physics is still unsatisfactory. The new generation of Cherenkov observatories and in particular the MAGIC telescope, allow for the first time the possibility to extend the measurement of GRBs from several tens up to hundreds of GeV energy range. Both leptonic and hadronic processes have been suggested to explain the possible GeV/TeV counterpart of GRBs. Observations with ground-based telescopes of very high energy photons (E>30 GeV) from these sources are going to play a key role in discriminating among the different proposed emission mechanisms, which are barely distinguishable at lower energies. MAGIC telescope observations of the GRB 090102 (z=1.547) field and Fermi Large Area Telescope (LAT) data in the same time interval are analysed to derive upper limits of the GeV/TeV emission. We compare these results to the expected emissions evaluated for different processes in the framework of a relativistic blast wave model for the afterglow. Simultaneous upper limits with Fermi and a Cherenkov telescope have been derived for this GRB observation. The results we obtained are compatible with the expected emission although the difficulties in predicting the HE and VHE emission for the afterglow of this event makes it difficult to draw firmer conclusions. Nonetheless, MAGIC sensitivity in the energy range of overlap with space-based instruments (above about 40 GeV) is about one order of magnitude better with respect to Fermi. This makes evident the constraining power of ground-based observations and shows that the MAGIC telescope has reached the required performance to make possible GRB multiwavelength studies in the very high energy range., 8 pages, 5 figures, 2 tables. Submitted to MNRAS

PSR J1023+0038 is the first millisecond pulsar discovered to pulsate in the visible band; such a detection took place when the pulsar was surrounded by an accretion disk and also showed X-ray pulsations. We report on the first high time resolution observational campaign of this transitional pulsar in the disk state, using simultaneous observations in the optical (TNG, NOT, TJO), X-ray (XMM-Newton, NuSTAR, NICER), infrared (GTC) and UV (Swift) bands. Optical and X-ray pulsations were detected simultaneously in the X-ray high intensity mode in which the source spends $\sim$ 70% of the time, and both disappeared in the low mode, indicating a common underlying physical mechanism. In addition, optical and X-ray pulses were emitted within a few km, had similar pulse shape and distribution of the pulsed flux density compatible with a power-law relation $F_{\nu} \propto \nu^{-0.7}$ connecting the optical and the 0.3-45 keV X-ray band. Optical pulses were detected also during flares with a pulsed flux reduced by one third with respect to the high mode; the lack of a simultaneous detection of X-ray pulses is compatible with the lower photon statistics. We show that magnetically channeled accretion of plasma onto the surface of the neutron star cannot account for the optical pulsed luminosity ($\sim 10^{31}$ erg/s). On the other hand, magnetospheric rotation-powered pulsar emission would require an extremely efficient conversion of spin-down power into pulsed optical and X-ray emission. We then propose that optical and X-ray pulses are instead produced by synchrotron emission from the intrabinary shock that forms where a striped pulsar wind meets the accretion disk, within a few light cylinder radii away, $\sim$ 100 km, from the pulsar., Comment: 26 pages, 14 figures, first submitted to ApJ on 2019, January 18

The very high energy (VHE; >100 GeV) source HESS J0632+057 has been recently confirmed as a \gamma-ray binary, a subclass of the high mass X-ray binary (HMXB) population, through the detection of an orbital period of 321 days. We performed a deep search for the emission of HESS J0632+057 in the GeV energy range using data from the Fermi Large Area Telescope (LAT). The analysis was challenging due to the source being located in close proximity to the bright \gamma-ray pulsar PSR J0633+0632 and lying in a crowded region of the Galactic plane where there is prominent diffuse emission. We formulated a Bayesian block algorithm adapted to work with weighted photon counts, in order to define the off-pulse phases of PSR J0633+0632. A detailed spectral-spatial model of a 5 deg circular region centred on the known location of HESS J0632+057 was generated to accurately model the LAT data. No significant emission from the location of HESS J0632+057 was detected in the 0.1-100 GeV energy range integrating over ~3.5 years of data; with a 95% flux upper limit of F_{0.1-100 GeV} < 3 x 10-8 ph cm-2 s-1. A search for emission over different phases of the orbit also yielded no significant detection. A search for source emission on shorter timescales (days--months) did not yield any significant detections. We also report the results of a search for radio pulsations using the 100-m Green Bank Telescope (GBT). No periodic signals or individual dispersed bursts of a likely astronomical origin were detected. We estimated the flux density limit of < 90/40 \mu Jy at 2/9 GHz. The LAT flux upper limits combined with the detection of HESS J0632+057 in the 136-400 TeV energy band by the MAGIC collaboration imply that the VHE spectrum must turn over at energies, Comment: 11 pages, 4 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS) Main Journal

Galaxy Conqueror is a serious game for citizen science. Its goal is to guide participants to identify galaxies in a region of the sky known as the Puppis' Window. Galaxy Conqueror is a on-line game, where each participant plays the role of a galactic explorer, studing a sector of the sky in search of galaxies and extraterrestrial life. When a participant thinks he has found a galaxy, he marks it and becomes its potential conqueror. Other players can express their opinion crediting or discrediting the potential conqueror. Players receive badges according to their performance. Initial evaluation shows that Galaxy Conqueror is an effective tool to channel the volunteers efforts to identify galaxies in the Puppis Window. The game is part of the Cientopolis platform for citizen science.

Nodos is a new project with the main goal to promote and build a comprehensive knowledge base of performing arts, artists, cultural groups & spaces, plays and festivals. The work of recording and preservation this kind of artistic expressions contributes to the preservation of the Intangible Cultural Heritage, as has been defined by UNESCO. One of the biggest challenges related to the recording of performing arts is given by the large number of people and dynamism present in the works. In many cities, which are an important center of artistic production, the amount of presented plays each year and the scarce regularity in regards to the functions' periodicity and the duration of the seasons, entails the loss of the records of many cultural pieces. This article introduces a manner of capturing and recording such cultural heritage by means of the definition of an ontology on performing arts and the use of a semantic wiki. The semantic wiki allows building and editing the information of works and people involved in the performing arts. This can easily be done by the artists themselves. These editions can be made while artistic events are happening, creating a living catalog that grows and records the passage of the performing arts.

In search for the counterpart to the Fermi-LAT source 3FGL J0838.8-2829, we performed a multi-wavelength campaign, in the X-ray band with Swift and XMM-Newton, performed infrared, optical (with OAGH, ESO-NTT and IAC80) and radio (ATCA) observations, as well as analysed archival hard X-ray data taken by INTEGRAL. We report on three X-ray sources consistent with the position of the Fermi-LAT source. We confirm the identification of the brightest object, RX J0838-2827, as a magnetic cataclysmic variable, that we recognize as an asynchronous system (not associated with the Fermi-LAT source). RX J0838-2827, is extremely variable in the X-ray and optical bands, and timing analysis reveals the presence of several periodicities modulating its X-ray and optical emission. The most evident modulations are interpreted as due to the binary system orbital period of ~1.64h and the white dwarf spin period of ~1.47h. A strong flux modulation at ~15h is observed at all energy bands, consistent with the beat frequency between spin and orbital periods. Optical spectra show prominent Hbeta, HeI and HeII emission lines Doppler-modulated at the orbital period and at the beat period. Therefore, RX J0838-2827, accretes through a diskless configuration and could be either a strongly asynchronous polar or a rare example of a pre-polar system in its way to reach synchronism. Among the other two X-ray sources, XMM J083850.4-282759 showed a variable X-ray emission, with a powerful flare lasting ~600s, similar to what is observed in transitional millisecond pulsars during the sub-luminous disc state: that would possibly associate this source with the Fermi-LAT source., Comment: 19 pages, 14 figures. MNRAS accepted (submitted on November 10th, 2016)

Astronomy and astrophysics 603, A31 (2017). doi:10.1051/0004-6361/201629540, We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi-LAT to cover the γ-ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV tohard X-rays; and GASP-WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the γ-ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self-Compton (SSC) scenarios. Aims. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters, hence providing a less biased interpretation than the “single-curve SSC model adjustment” typically reported in the literature. Methods. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid-scan shows that the flaring activity around May 22 cannot be modeled adequately with a one-zone SSC scenario (using an electron energy distribution with two breaks), while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5-month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X-rays and very-high-energy (>100 GeV, VHE) γ rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA), cannot be satisfactorily reproduced by either a one-zone or a two-independent-zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub-hour timescales (detected at VHE γ rays). Results. The higher variability in the VHE emission and lack of correlation with the X-ray emission indicate that, at least during the 4.5-month observing campaign in 2009, the highest energy (and most variable) electrons that are responsible for the VHE γ rays do not make a dominant contribution to the ~1 keV emission. Alternatively, there could be a very variable component contributing to the VHE γ-ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid-scan show that there is some degeneracy in both the one-zone and the two-zone SSC scenarios probed, with several combinations of model parameters yielding a similar model-to-data agreement, and some parameters better constrained than others. The observed γ-ray flaring activity, with the EVPA rotation coincident with the first γ-ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties., Published by EDP Sciences, Les Ulis

We estimate the molecular mass around CTA 1 using data from Planck and the Harvard CO survey. We observe that the molecular mass in the vicinity of the complex is not enough to explain the TeV emission observed by VERITAS, even under favorable assumptions for the cosmic-ray acceleration properties of the supernova remnant. This supports the idea that the TeV emission comes from the PWN. Here, we model the spectrum of the PWN at possible different stages of its evolution, including both the dynamics of the PWN and the SNR and their interaction via the reverse shock. We have included in the model the energy lost via radiation by particles and the particles escape when computing the pressure produced by the gas. This leads to an evolving energy partition, since for the same instantaneous sharing of the injection of energy provided by the rotational power, the field and the particles are affected differently by radiation and losses. We present the model, and study in detail how the spectrum of a canonical isolated PWN is affected during compression and re-expansion and how this may impact on the CTA 1 case. By exploring the phase-space of parameters that lead to radii in agreement with those observed, we then analyze different situations that might represent the current stage of the CTA 1 PWN, and discuss caveats and requirements of each one., Comment: 13 pages, 8 figures, accepted for publication in MNRAS

The BL Lac object 1ES 1011+496 was discovered at Very High Energy gamma-rays by MAGIC in spring 2007. Before that the source was little studied in different wavelengths. Therefore a multi-wavelength (MWL) campaign was organized in spring 2008. Along MAGIC, the MWL campaign included the Metsahovi radio observatory, Bell and KVA optical telescopes and the Swift and AGILE satellites. MAGIC observations span from March to May, 2008 for a total of 27.9 hours, of which 19.4 hours remained after quality cuts. The light curve showed no significant variability. The differential VHE spectrum could be described with a power-law function. Both results were similar to those obtained during the discovery. Swift XRT observations revealed an X-ray flare, characterized by a harder when brighter trend, as is typical for high synchrotron peak BL Lac objects (HBL). Strong optical variability was found during the campaign, but no conclusion on the connection between the optical and VHE gamma-ray bands could be drawn. The contemporaneous SED shows a synchrotron dominated source, unlike concluded in previous work based on nonsimultaneous data, and is well described by a standard one zone synchrotron self Compton model. We also performed a study on the source classification. While the optical and X-ray data taken during our campaign show typical characteristics of an HBL, we suggest, based on archival data, that 1ES 1011+496 is actually a borderline case between intermediate and high synchrotron peak frequency BL Lac objects., 13 pages, accepted for publication in MNRAS

The detection of pulsations from an X-ray binary is an unambiguous signature of the presence of a neutron star in the system. When the pulsations are missed in the radio band, their detection at other wavelengths, such as X-ray or gamma-rays, requires orbital demodulation, since the length of the observations is often comparable to, or longer than, the system orbital period. A detailed knowledge of the orbital parameters of binary systems plays a crucial role in the detection of the spin period of pulsars since any uncertainty in their determination translates into a loss in the coherence of a signal during the demodulation process. In this paper, we present an analytical study aimed at unveiling how the uncertainties in the orbital parameters might impact on periodicity searches. We find a correlation between the power of the signal in the demodulated arrival time series and the uncertainty in each of the orbital parameters. This correlation is also a function of the pulsar frequency. We test our analytical results with numerical simulations, finding good agreement between them. Finally, we apply our study to the cases of LS 5039 and LS I +61 303 and consider the current level of uncertainties in the orbital parameters of these systems and their impact on a possible detection of a hosted pulsar. We also discuss the possible appearance of a sideband ambiguity in real data. The latter can occur when, due to the use of uncertain orbital parameters, the power of a putative pulsar is distributed in frequencies lying near the pulsar period. Even if the appearance of a sideband is already a signature of a pulsar component, it may introduce an ambiguity in the determination of its period. We present here a method to solve the sideband issue.

In this work, we present a leptonic, time-dependent model of pulsar wind nebulae (PWNe). The model seeks a solution for the lepton distribution function considering the full time-energy dependent diffusion-loss equation. The time-dependent lepton population is balanced by injection, energy losses, and escape. We include synchrotron, inverse Compton (IC, with the cosmic-microwave background as well as with IR/optical photon fields), self-synchrotron Compton (SSC), and bremsstrahlung processes, all devoid of any radiative approximations. With this model in place we focus on the Crab nebula as an example and present its time dependent evolution. Afterwards, we analyze the impact of different approximations made at the level of the diffusion-loss equation, as can be found in the literature. Whereas previous models ignored the escape term, e.g., with the diffusion-loss equation becoming advective, others approximated the losses as catastrophic, so that the equation has only time derivatives. Additional approximations are also described and computed. We show which is the impact of these approaches in the determination of the PWN evolution. In particular, we find the time-dependent deviation of the multi-wavelength spectrum and the best-fit parameters obtained with the complete and the approximate models.