The young open cluster Berkeley 55

We present UBV photometry of the highly reddened and poorly studied open cluster Berkeley 55, revealing an important population of B-type stars and several evolved stars of high luminosity. Intermediate-resolution far-red spectra of several candidate members confirm the presence of one F-type supergiant and six late supergiants or bright giants. The brightest blue stars are mid-B giants. Spectroscopic and photometric analyses indicate an age 50 ± 10 Myr. The cluster is located at a distance d ≈ 4 kpc, consistent with other tracers of the Perseus Arm in this direction. Berkeley 55 is thus a moderately young open cluster with a sizable population of candidate red (super)giant members, which can provide valuable information about the evolution of intermediate-mass stars.

A VLT/FLAMES survey for massive binaries in Westerlund 1. III. The WC9d binary W239 and implications for massive stellar evolution

Context. There is growing evidence that a treatment of binarity amongst OB stars is essential for a full theory of stellar evolution. However the binary properties of massive stars – frequency, mass ratio & orbital separation – are still poorly constrained. Aims. In order to address this shortcoming we have undertaken a multiepoch spectroscopic study of the stellar population of the young massive cluster Westerlund 1. In this paper we present an investigation into the nature of the dusty Wolf-Rayet star and candidate binary W239. Methods. To accomplish this we have utilised our spectroscopic data in conjunction with multi-year optical and near-IR photometric observations in order to search for binary signatures. Comparison of these data to synthetic non-LTE model atmosphere spectra were used to derive the fundamental properties of the WC9 primary. Results. We found W239 to have an orbital period of only ~5.05 days, making it one of the most compact WC binaries yet identified. Analysis of the long term near-IR lightcurve reveals a significant flare between 2004-6. We interpret this as evidence for a third massive stellar component in the system in a long period (>6 yr), eccentric orbit, with dust production occuring at periastron leading to the flare. The presence of a near-IR excess characteristic of hot (~1300 K) dust at every epoch is consistent with the expectation that the subset of persistent dust forming WC stars are short (<1 yr) period binaries, although confirmation will require further observations. Non-LTE model atmosphere analysis of the spectrum reveals the physical properties of the WC9 component to be fully consistent with other Galactic examples. Conclusions. The simultaneous presence of both short period Wolf-Rayet binaries and cool hypergiants within Wd 1 provides compelling evidence for a bifurcation in the post-Main Sequence evolution of massive stars due to binarity. Short period O+OB binaries will evolve directly to the Wolf-Rayet phase, either due to an episode of binary mediated mass loss – likely via case A mass transfer or a contact configuration – or via chemically homogenous evolution. Conversely, long period binaries and single stars will instead undergo a red loop across the HR diagram via a cool hypergiant phase. Future analysis of the full spectroscopic dataset for Wd 1 will constrain the proportion of massive stars experiencing each pathway; hence quantifying the importance of binarity in massive stellar evolution up to and beyond supernova and the resultant production of relativistic remnants.

NGC 7419 as a template for red supergiant clusters

Context. The open cluster NGC 7419 is known to contain five red supergiants and a very high number of Be stars. However, there are conflicting reports about its age and distance that prevent a useful comparison with other clusters. Aims. We intend to obtain more accurate parameters for NGC 7419, using techniques different from those of previous authors, so that it may be used as a calibrator for more obscured clusters. Methods. We obtained Strömgren photometry of the open cluster NGC 7419, as well as classification spectroscopy of ~20 stars in the area. We then applied standard analysis and classification techniques. Results. We find a distance of 4 ± 0.4 kpc and an age of 14 ± 2 Myr for NGC 7419. The main-sequence turn-off is found at spectral type B1, in excellent agreement. We identify 179 B-type members, implying that there are more than 1200 M⊙ in B stars at present. Extrapolating this to lower masses indicates an initial cluster mass of between 7000 and 10 000 M⊙, depending on the shape of the initial mass function. We find a very high fraction (≈40%) of Be stars around the turn-off, but very few Be stars at lower masses. We also report for the first time a strong variability in the emission characteristics of Be stars. We verified that the parameters of the red supergiant members can be used to obtain accurate cluster parameters. Conclusions. NGC 7419 is sufficiently massive to serve as a testbed for theoretical predictions and as a template to compare more obscured clusters. The distribution of stars above the main-sequence turn-off is difficult to accommodate with current evolutionary tracks. Though the presence of five red supergiants is marginally consistent with theoretical expectations, the high number of Be stars and very low number of luminous evolved B stars hint at some unknown physical factor that is not considered in current synthesis models.

Los medios online y la ¿crisis? de la planificación de medios publicitarios

Los medios online representan actualmente una gran apuesta para la publicidad. Desde la planificación de medios publicitarios, los nuevos medios ofrecen otros caminos para llegar al público, pero añaden mayor complejidad. La capacidad comunicativa de los medios online y el mayor consumo de esos medios por parte de la población abre el debate de la necesidad de replantear el enfoque de la planificación de medios, digamos, tradicional, cuya estructura y procesos de trabajo se desarrollaron cuando los medios eran offline. Así, este artículo proporciona una panorámica general de la influencia de los nuevos medios en la planificación. Para ello, en primer lugar, describe el escenario actual, analizando la penetración y las inversiones publicitarias en Internet. Además, expone los principales soportes online según su proximidad a la concepción de la planificación de medios offline. En segundo lugar, aborda los retos actuales en la medición de los nuevos medios como síntoma del impulso del cambio de modelo. Finalmente, el artículo termina exponiendo algunas tendencias que se presentan como motores de cambio. Sin embargo, tras este análisis se advierte que tales aspectos no modificarían la esencia de la planificación de medios, por lo que cabe cuestionarse si se puede hablar de crisis, o si los nuevos medios están mostrando la necesidad de que la investigación y planificación se comprometa con este nuevo escenario.

Providing Collaborative Support to Virtual and Remote Laboratories

Virtual and remote laboratories (VRLs) are e-learning resources that enhance the accessibility of experimental setups providing a distance teaching framework which meets the student's hands-on learning needs. In addition, online collaborative communication represents a practical and a constructivist method to transmit the knowledge and experience from the teacher to students, overcoming physical distance and isolation. This paper describes the extension of two open source tools: (1) the learning management system Moodle, and (2) the tool to create VRLs Easy Java Simulations (EJS). Our extension provides: (1) synchronous collaborative support to any VRL developed with EJS (i.e., any existing VRL written in EJS can be automatically converted into a collaborative lab with no cost), and (2) support to deploy synchronous collaborative VRLs into Moodle. Using our approach students and/or teachers can invite other users enrolled in a Moodle course to a real-time collaborative experimental session, sharing and/or supervising experiences at the same time they practice and explore experiments using VRLs.

TrendMiner: Large-scale Cross-lingual Trend Mining Summarization of Real-time Media Streams

El reciente crecimiento masivo de medios on-line y el incremento de los contenidos generados por los usuarios (por ejemplo, weblogs, Twitter, Facebook) plantea retos en el acceso e interpretación de datos multilingües de manera eficiente, rápida y asequible. El objetivo del proyecto TredMiner es desarrollar métodos innovadores, portables, de código abierto y que funcionen en tiempo real para generación de resúmenes y minería cross-lingüe de medios sociales a gran escala. Los resultados se están validando en tres casos de uso: soporte a la decisión en el dominio financiero (con analistas, empresarios, reguladores y economistas), monitorización y análisis político (con periodistas, economistas y políticos) y monitorización de medios sociales sobre salud con el fin de detectar información sobre efectos adversos a medicamentos.

VdBH 222: a starburst cluster in the inner Milky Way

Context. It has been suggested that the compact open cluster VdBH 222 is a young massive distant object. Aims. We set out to characterise VdBH 222 using a comprehensive set of multi-wavelength observations. Methods. We obtained multi-band optical (UBVR) and near-infrared (JHKS) photometry of the cluster field, as well as multi-object and long-slit optical spectroscopy for a large sample of stars in the field. We applied classical photometric analysis, as well as more sophisticated methods using the CHORIZOS code, to determine the reddening to the cluster. We then plotted dereddened HR diagrams and determined cluster parameters via isochrone fitting. Results. We have identified a large population of luminous supergiants confirmed as cluster members via radial velocity measurements. We find nine red supergiants (plus one other candidate) and two yellow supergiants. We also identify a large population of OB stars. Ten of them are bright enough to be blue supergiants. The cluster lies behind ≈7.5 mag of extinction for the preferred value of RV = 2.9. Isochrone fitting allows for a narrow range of ages between 12 and 16 Ma. The cluster radial velocity is compatible with distances of ~6 and ~10 kpc. The shorter distance is inconsistent with the age range and Galactic structure. The longer distance implies an age ≈ 12 Ma and a location not far from the position where some Galactic models place the far end of the Galactic bar. Conclusions. VdBH 222 is a young massive cluster with a likely mass >20 000 M⊙. Its population of massive evolved stars is comparable to that of large associations, such as Per OB1. Its location in the inner Galaxy, presumably close to the end of the Galactic bar, adds to the increasing evidence for vigorous star formation in the inner regions of the Milky Way.

Recursos didácticos online para el aprendizaje Redes de Computadores en el grado de Informática

En este trabajo se analiza el uso que se hace de un conjunto de recursos multimedia incluidos en un curso en línea de acceso libre y gratuito sobre Redes de Computadores. Este estudio se lleva a cabo a partir de la interacción que un grupo de estudiantes de ingenierías tienen con estos recursos durante su proceso de aprendizaje. Estos recursos educacionales se basan en una aproximación Web 2.0 y por si solos forman parte de una metodología docente fundamentada en el autoaprendizaje a distancia. Entre estos recursos destaca el uso de un blogs, OCW, videos y simulaciones. Estos recursos educativos ‘open-free’ han sido diseñados como elementos que facilitan la aplicación de una metodología de enseñanza a distancia basada en muchos casos en el auto-aprendizaje y en potenciar el aprendizaje autónomo. Además, la percepción que se tiene sobre estos recursos juega un papel relevante en la aceptación de estos por parte del estudiante. Cualquier nuevo recurso educativo que se diseñe, además de didáctico, tiene que ser atractivo y de un uso sencillo e interactivo para el estudiante. El trabajo que aquí se presenta, busca analizar la usabilidad de estos recursos por parte del estudiante para desarrollar futuras mejoras.

Orbital and Physical Properties of the σ Ori Aa, Ab, B Triple System

We provide a complete characterization of the astrophysical properties of the σ Ori Aa, Ab, B hierarchical triple system and an improved set of orbital parameters for the highly eccentric σ Ori Aa, Ab spectroscopic binary. We compiled a spectroscopic data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filhés method for a detailed orbital analysis of the radial velocity curves and performed a combined quantitative spectroscopic analysis of the σ Ori Aa, Ab, B system by means of the stellar atmosphere code FASTWIND. We used our own plus other available information on photometry and distance to the system for measuring the radii, luminosities, and spectroscopic masses of the three components. We also inferred evolutionary masses and stellar ages using the Bayesian code BONNSAI. The orbital analysis of the new radial velocity curves led to a very accurate orbital solution of the σ Ori Aa, Ab pair. We provided indirect arguments indicating that σ Ori B is a fast-rotating early B dwarf. The FASTWIND+BONNSAI analysis showed that the Aa, Ab pair contains the hottest and most massive components of the triple system while σ Ori B is a bit cooler and less massive. The derived stellar ages of the inner pair are intriguingly younger than the one widely accepted for the σ Orionis cluster, at 3 ± 1 Ma. The outcome of this study will be of key importance for a precise determination of the distance to the σ Orionis cluster, the interpretation of the strong X-ray emission detected for σ Ori Aa, Ab, B, and the investigation of the formation and evolution of multiple massive stellar systems and substellar objects.

Behaviours, Processes and Probabilistic Environmental Functions in H-Open Systems

The Patten’s Theory of the Environment, supposes an impotent contribution to the Theoretical Ecology. The hypothesis of the duality of environments, the creaon and genon functions and the three developed propositions are so much of great importance in the field of the Applied Mathematical as Ecology. The authors have undertaken an amplification and revision of this theory, developing the following steps: 1) A theory of processes. 2) A definition of structural and behavioural functions. 3) A probabilistic definition of the environmental functions. In this paper the authors develop the theory of behavioural functions, begin the theory of environmental functions and give a complementary focus to the theory of processes that has been developed in precedent papers.

Integrated taphonomy in an open-marine platform: The Lower Cretaceous of Sierra Helada (Betic Cordillera, SE Spain)

A detailed taphonomic analysis was carried out on the lower Albian deposits of the Sierra Helada section (Alicante, Betic Cordillera, southeastern Spain). Ten taphonomic characters were studied and ten skeletal concentrations were defined on the basis of taphonomic features and the dominant taxa. Cluster analysis was performed on the dataset represented by the abundance of the taphonomic characters in each skeletal concentration. This enabled the definition of four different taphonomic categories: 1) skeletal concentrations characterized by the presence of fossils preserved in life position, 2) skeletal concentrations showing very little physical reworking, 3) skeletal concentrations related to high-energy background conditions, and 4) skeletal concentrations produced by medium- to high-energy events. Four taphofacies were defined on the basis of the main sedimentological features and the most representative skeletal concentrations. Taphofacies A represents the low energy outer platform, rich in skeletal concentrations with echinoids in life position and only slightly reworked. The second taphofacies (taphofacies B) is very rich in reworked echinoid tests and calcarenitic beds and records the transition to shallower areas, while taphofacies C shows abundant thick-bedded calcarenites and skeletal concentrations produced by sediment transport and rapid deposition. Finally, cross-bedded grainstone beds, which are rich in fine-grained fragmented, locally reoriented bioclasts (taphofacies D), record the existence of shifting sandy dunes in the shallow inner part of the platform.

Orbscan Topography in Primary Open-Angle Glaucoma

Purpose: To compare anterior and posterior corneal curvatures between eyes with primary open-angle glaucoma (POAG) and healthy eyes. Methods: This is a prospective, cross-sectional, observer-masked study. A total of 138 white subjects (one eye per patient) were consecutively recruited; 69 eyes had POAG (study group), and the other 69 comprised a group of healthy control eyes matched for age and central corneal pachymetry with the study ones. Exclusion criteria included any corneal or ocular inflammatory disease, previous ocular surgery, or treatment with carbonic anhydrase inhibitors. The same masked observer performed Goldmann applanation tonometry, ultrasound pachymetry, and Orbscan II topography in all cases. Central corneal thickness, intraocular pressure, and anterior and posterior topographic elevation maps were analyzed and compared between both groups. Results: Patients with POAG had greater forward shifting of the posterior corneal surface than that in healthy control eyes (p < 0.01). Significant differences in anterior corneal elevation between controls and POAG eyes were also found (p < 0.01). Conclusions: Primary open-angle glaucoma eyes have a higher elevation of the posterior corneal surface than that in central corneal thickness–matched nonglaucomatous eyes.

Assessment of Web Content Accessibility Levels in Spanish Official Online Education Environments

Diversity-based designing, or the goal of ensuring that web-based information is accessible to as many diverse users as possible, has received growing international acceptance in recent years, with many countries introducing legislation to enforce it. This paper analyses web content accessibility levels in Spanish education portals according to the international guidelines established by the World Wide Web Consortium (W3C) and the Web Accessibility Initiative (WAI). Additionally, it suggests the calculation of an inaccessibility rate as a tool for measuring the degree of non-compliance with WAI Guidelines 2.0 as well as illustrating the significant gap that separates people with disabilities from digital education environments (with a 7.77% average). A total of twenty-one educational web portals with two different web depth levels (42 sampling units) were assessed for this purpose using the automated analysis tool Web Accessibility Test 2.0 (TAW, for its initials in Spanish). The present study reveals a general trend towards non-compliance with the technical accessibility recommendations issued by the W3C-WAI group (97.62% of the websites examined present mistakes in Level A conformance). Furthermore, despite the increasingly high number of legal and regulatory measures about accessibility, their practical application still remains unsatisfactory. A greater level of involvement must be assumed in order to raise awareness and enhance training efforts towards accessibility in the context of collective Information and Communication Technologies (ICTs), since this represents not only a necessity but also an ethical, social, political and legal commitment to be assumed by society.

Online Media and Crisis? of Advertising Media Planning

Nowadays, online media represent a great choice for advertising. From de advertising media planning, new media give new ways to reach the consumers, but they also add more complexity. The communication capacity of online media and the greater use of that media by part of the users open up the debate about the necessity of rethinking the approach of the ‘traditional’ advertising media planning, which structure and work processes were developed when media were offline. So, this article gives a panoramic view about the influence of new media in advertising media planning. To do this, in first place, describes the current scenario, analyzing the penetration and advertising expenditure in Internet. Also, it shows the main online media according to their proximity to the offline advertising media planning conception. In second place, this article addresses the current challenges at measuring new media as a symptom of the impulse at the change of model. Finally, the article ends up showing some trends that are presented as drivers of change. However, after this analysis, comes up the point that those aspects would not change the essence of advertising media planning, so it is questionable if we can speak of a crisis or, instead, if new media are showing the necessity that media planning have to be involved with this new scenario.

A VLT/FLAMES survey for massive binaries in Westerlund 1. IV. Wd1-5 – binary product and a pre-supernova companion for the magnetar CXOU J1647-45?

Context. The first soft gamma-ray repeater was discovered over three decades ago, and was subsequently identified as a magnetar, a class of highly magnetised neutron star. It has been hypothesised that these stars power some of the brightest supernovae known, and that they may form the central engines of some long duration gamma-ray bursts. However there is currently no consenus on the formation channel(s) of these objects. Aims. The presence of a magnetar in the starburst cluster Westerlund 1 implies a progenitor with a mass ≥40 M⊙, which favours its formation in a binary that was disrupted at supernova. To test this hypothesis we conducted a search for the putative pre-SN companion. Methods. This was accomplished via a radial velocity survey to identify high-velocity runaways, with subsequent non-LTE model atmosphere analysis of the resultant candidate, Wd1-5. Results. Wd1-5 closely resembles the primaries in the short-period binaries, Wd1-13 and 44, suggesting a similar evolutionary history, although it currently appears single. It is overluminous for its spectroscopic mass and we find evidence of He- and N-enrichement, O-depletion, and critically C-enrichment, a combination of properties that is difficult to explain under single star evolutionary paradigms. We infer a pre-SN history for Wd1-5 which supposes an initial close binary comprising two stars of comparable (~ 41 M⊙ + 35 M⊙) masses. Efficient mass transfer from the initially more massive component leads to the mass-gainer evolving more rapidly, initiating luminous blue variable/common envelope evolution. Reverse, wind-driven mass transfer during its subsequent WC Wolf-Rayet phase leads to the carbon pollution of Wd1-5, before a type Ibc supernova disrupts the binary system. Under the assumption of a physical association between Wd1-5 and J1647-45, the secondary is identified as the magnetar progenitor; its common envelope evolutionary phase prevents spin-down of its core prior to SN and the seed magnetic field for the magnetar forms either in this phase or during the earlier episode of mass transfer in which it was spun-up. Conclusions. Our results suggest that binarity is a key ingredient in the formation of at least a subset of magnetars by preventing spin-down via core-coupling and potentially generating a seed magnetic field. The apparent formation of a magnetar in a Type Ibc supernova is consistent with recent suggestions that superluminous Type Ibc supernovae are powered by the rapid spin-down of these objects.