Materiales y recursos digitales

La oferta de herramientas, materiales y contenidos educativos digitales es ilimitada y obliga al profesorado a buscarlos, seleccionarlos y almacenarlos de una forma muy distinta a cómo estaba acostumbrado. ¿De qué recursos dispone? ¿Cómo puede organizarlos? ¿Y compartirlos

Astrophysical parameters and orbital solution of the peculiar X-ray transient IGR J00370+6122

BD+6073 is the optical counterpart of the X-ray source IGR J00370+6122, a probable accretion-powered X-ray pulsar. The X-ray light curve of this binary system shows clear periodicity at 15.7 d, which has been interpreted as repeated outbursts around the periastron of an eccentric orbit. We obtained high-resolution spectra of BD+6073 at different epochs. We used the FASTWind code to generate a stellar atmosphere model to fit the observed spectrum and obtain physical magnitudes. The synthetic spectrum was used as a template for cross-correlation with the observed spectra to measure radial velocities. The radial velocity curve provided an orbital solution for the system. We have also analysed the RXTE/ASM and Swift/BAT light curves to confirm the stability of the periodicity. BD +6073 is a BN0.7 Ib low-luminosity supergiant located at an approximate distance of 3.1 kpc, in the CasOB4 association. We derive Teff=24000 K and log gc=3.0, and chemical abundances consistent with a moderately high level of evolution. The spectroscopic and evolutionary masses are consistent at the 1 sigma level with a mass of 15 solar masses. The recurrence time of the X-ray flares is the orbital period of the system. The NS is in a high eccentricity (e=0.56) orbit, and the X-ray emission is strongly peaked around orbital phase 0.2, though the observations are consistent with some level of X-ray activity happening at all orbital phases. The X-ray behaviour of IGR J00370+6122 is reminiscent of intermediate SFXTs, though its peak luminosity is rather low. The orbit is somewhat wider than those of classical persistent supergiant X-ray binaries, which, combined with the low luminosity of the mass donor, explains the low X-ray luminosity. IGR J00370+6122 will likely evolve towards a persistent supergiant system, highlighting the evolutionary connection between different classes of wind-accreting X-ray sources.Comment: Accepted for publication in A&

On some noteworthy alpine or subalpine Hyaloscyphaceae (Leotiales) found in the Pyrenees

Se describen, ilustran y comentan cuatro especies pertenecientes a Hyaloscyphaceae (Leotiales), procedentes de comunidades alpinas y subalpinas de Cataluña y Andorra, nunca antes citadas en la Península Ibérica. Se trata de Lachnum latebricola (Rehm) R. Galán et Raitv., Hyalopeziza nectrioidea (Rehm) Raschle, Incrupila dennisii (Müller) Müller y Lachnellula fuscosanguinea (Rehm) Dennis.Four alpine and subalpine species of the Hyaloscyphaceae (Leotiales, Ascomycotina) are described, illustrated and discussed. They wete collected in Catalonia and Andorra, and they are never been previously reported from the Iberian Peninsula. These are: Lachnum latebricola (Rehm) R. Galán et Raitv., Hyalopeziza nectrioidea (Rehm) Raschle, Incrupila dennisii (Müller) Müller and Lachnellula fuscosanguinea (Rehm) Dennis

On some noteworthy alpine or subalpine Hyaloscyphaceae (Leotiales) found in the Pyrenees

Four alpine and subalpine species of the Hyaloscyphaceae (Leotiales, Ascomycotina) are described, illustrated and discussed. They wete collected in Catalonia and Andorra, and they are never been previously reported from the Iberian Peninsula. These are: Lachnum latebricola (Rehm) R. Galán et Raitv., Hyalopeziza nectrioidea (Rehm) Raschle, Incrupila dennisii (Müller) Müller and Lachnellula fuscosanguinea (Rehm) Dennis.Se describen, ilustran y comentan cuatro especies pertenecientes a Hyaloscyphaceae (Leotiales), procedentes de comunidades alpinas y subalpinas de Cataluña y Andorra, nunca antes citadas en la Península Ibérica. Se trata de Lachnum latebricola (Rehm) R. Galán et Raitv., Hyalopeziza nectrioidea (Rehm) Raschle, Incrupila dennisii (Müller) Müller y Lachnellula fuscosanguinea (Rehm) Dennis

Quantum time uncertainty in Schwarzschild-anti-de Sitter black holes

The combined action of gravity and quantum mechanics gives rise to a minimum time uncertainty in the lowest order approximation of a perturbative scheme, in which quantum effects are regarded as corrections to the classical spacetime geometry. From the nonperturbative point of view, both gravity and quantum mechanics are treated on equal footing in a description that already contains all possible backreaction effects as those above in a nonlinear manner. In this paper, the existence or not of such minimum time uncertainty is analyzed in the context of Schwarzschild-anti-de Sitter black holes using the isolated horizon formalism. We show that from a perturbative point of view, a nonzero time uncertainty is generically present owing to the energy scale introduced by the cosmological constant, while in a quantization scheme that includes nonperturbatively the effects of that scale, an arbitrarily high time resolution can be reached.Comment: 10 pages, version published in Physical Review

Inter-rater and intra-rater reliability of the extended TUG test in elderly participants

Background: To analyse the reliability, variance and execution time of the Extended Timed Up and Go (Extended TUG) test in three age groups of elderly participants (G1: 55–64 years; G2: 65–74 years; G3: 75–85 years). Methods: An analytical cross-sectional study of 114 recruited participants (63 women) of average age 70.17 (± 7.3) years was undertaken. Each participant performed the Extended TUG three consecutive times, with a rest break between tests of 120 s. Both the intragroup and intergroup reliability of the measurements in the Extended TUG were analysed. Results: The reliability of the Extended TUG test is excellent for the first and second decades but drops down to good for the third decade. Specifically, intragroup reliability ranged from 0.784 for G3 to 0.977 for G1 (G2 = 0.858). Intergroup reliability, compared with intragroup reliability, was slightly lower, ranging between 0.779 for G3 and 0.972 for G1 (G2 = 0.853). Conclusion: The reliability of the Extended TUG test progressively decreases with increasing age, being excellent for the younger age groups and good for the oldest age group