On the occurrence of Iphiculus eliasi Hyzny & Gross, 2016 (Decapoda, Brachyura, Leucosioidea) from the Miocene of Catalonia (northeastern Iberian Peninsula)

Recovery of two specimens of leucosioid crabs in Langhian (middle Miocene) strata at Vilafranca del Penedes (Alt Penedes, Catalonia) and a re-examination of another leucosioid from the palaeontological collections of the Vinseum (Vilafranca del Penedes, Catalonia) have led us to consider all of these as conspecific with Iphiculus eliasi Hyzny & Gross, 2016, described first from the middle Miocene of Austria. The sternal and pleonal remains preserved in one of the Catalonian specimens allows to emend the original description of the species. Likewise, a specimen from the middle Miocene of Portugal, previously described as a paguroid, is herein transferred to this species. The occurrence of I. eliasi, either in outcrops along the northeastern and southwestern coasts of the Iberian Peninsula, corroborates the close relationship between decapod assemblages which inhabited similar palaeoenvironments in the Central Paratethys, the western Mediterranean and even the nearest Atlantic waters, during the middle Miocene

Montecarlo simulation of the role of defects as the melting mechanism

We study in this paper the melting transition of a crystal of fcc structure with the Lennard-Jones potential, by using isobaric-isothermal Monte Carlo simulations. Local and collective updates are sequentially used to optimize the convergence. We show the important role played by defects in the melting mechanism in favor of modern melting theories.Comment: 6 page, 10 figures included. Corrected version to appear in Phys. Rev.

Orthosymplectic Jordan superalgebras and the Wedderburn principal theorem

An analogue of the Wedderburn Principal Theorem (WPT) is considered for finite-dimensional Jordan superal-gebras A with solvable radical N, N² = 0, and such that A/N ≅ Jospn|2m(F), where F is a field of characteristic zero. We prove that the WPT is valid under some restrictions over the irreducible Jospn|2m(F)-bimodules contained in N, and show with counter-examples that these restrictions cannot be weakened. Introductio

A conjecture on Exceptional Orthogonal Polynomials

Exceptional orthogonal polynomial systems (X-OPS) arise as eigenfunctions of Sturm-Liouville problems and generalize in this sense the classical families of Hermite, Laguerre and Jacobi. They also generalize the family of CPRS orthogonal polynomials. We formulate the following conjecture: every exceptional orthogonal polynomial system is related to a classical system by a Darboux-Crum transformation. We give a proof of this conjecture for codimension 2 exceptional orthogonal polynomials (X2-OPs). As a by-product of this analysis, we prove a Bochner-type theorem classifying all possible X2-OPS. The classification includes all cases known to date plus some new examples of X2-Laguerre and X2-Jacobi polynomials

On the stellar halo metallicity profile of Milky Way-like galaxies in the Auriga simulations

A recent observational study of haloes of nearby Milky Way-like galaxies shows that only half (four out of eight) of the current sample exhibits strong negative metallicity ([Fe/H]) gradients. This is at odds with predictions from hydrodynamical simulations where such gradients are ubiquitous. In this Letter, we use high-resolution cosmological hydrodynamical simulations to study the [Fe/H] distribution of galactic haloes. We find that kinematically selected stellar haloes, including both in situ and accreted particles, have an oblate [Fe/H] distribution. Spherical [Fe/H] radial profiles show strong negative gradients within 100 kpc, in agreement with previous numerical results. However, the projected median [Fe/H] profiles along the galactic disc minor axis, typically obtained in observations, are significantly flatter. The median [Fe/H] values at a given radius are larger for the spherical profiles than for the minor axis profiles by as much as 0.4 dex within the inner 50 kpc. Similar results are obtained if only the accreted stellar component is considered indicating that the differences between spherical and minor axis profiles are not purely driven by heated disc star particles formed in situ. Our study highlights the importance of performing careful comparisons between models and observations of halo [Fe/H] distributions

On the relevance of chaos for halo stars in the solar neighbourhood II

In a previous paper based on dark matter only simulations we show that, in the approximation of an analytic and static potential describing the strongly triaxial and cuspy shape of Milky Way-sized haloes, diffusion due to chaotic mixing in the neighbourhood of the Sun does not efficiently erase phase space signatures of past accretion events. In this second paper we further explore the effect of chaotic mixing using multicomponent Galactic potential models and solar neighbourhood-like volumes extracted from fully cosmological hydrodynamic simulations, thus naturally accounting for the gravitational potential associated with baryonic components, such as the bulge and disc. Despite the strong change in the global Galactic potentials with respect to those obtained in dark matter only simulations, our results confirm that a large fraction of halo particles evolving on chaotic orbits exhibit their chaotic behaviour after periods of time significantly larger than a Hubble time. In addition, significant diffusion in phase space is not observed on those particles that do exhibit chaotic behaviour within a Hubble time

Too dense to go through: the role of low-mass clusters in the pre-processing of satellite galaxies

Galaxie

Relativistic Hydrodynamic Evolutions with Black Hole Excision

We present a numerical code designed to study astrophysical phenomena involving dynamical spacetimes containing black holes in the presence of relativistic hydrodynamic matter. We present evolutions of the collapse of a fluid star from the onset of collapse to the settling of the resulting black hole to a final stationary state. In order to evolve stably after the black hole forms, we excise a region inside the hole before a singularity is encountered. This excision region is introduced after the appearance of an apparent horizon, but while a significant amount of matter remains outside the hole. We test our code by evolving accurately a vacuum Schwarzschild black hole, a relativistic Bondi accretion flow onto a black hole, Oppenheimer-Snyder dust collapse, and the collapse of nonrotating and rotating stars. These systems are tracked reliably for hundreds of M following excision, where M is the mass of the black hole. We perform these tests both in axisymmetry and in full 3+1 dimensions. We then apply our code to study the effect of the stellar spin parameter J/M^2 on the final outcome of gravitational collapse of rapidly rotating n = 1 polytropes. We find that a black hole forms only if J/M^2<1, in agreement with previous simulations. When J/M^2>1, the collapsing star forms a torus which fragments into nonaxisymmetric clumps, capable of generating appreciable ``splash'' gravitational radiation.Comment: 17 pages, 14 figures, submitted to PR

Aurigaia: mock Gaia DR2 stellar catalogues from the Auriga cosmological simulations

We present and analyse mock stellar catalogues that match the selection criteria and observables (including uncertainties) of the Gaia satellite data release 2 (DR2). The source are six cosmological high-resolution magneto-hydrodynamic ΛCDM zoom simulations of the formation of Milky Way analogues from the AURIGA project. Mock data are provided for stars with V 20 deg. The mock catalogues are made using two different methods: the public SNAPDRAGONS code, and a method based on that of Lowing et al. (2015) that preserves the phase-space distribution of the model stars. These publicly available catalogues contain five-parameter astrometry, radial velocities, multiband photometry, stellar parameters, dust extinction values, and uncertainties in all these quantities. In addition, we provide the gravitational potential and information on the origin of each star. By way of demonstration, we apply the mock catalogues to analyses of the young stellar disc and the stellar halo. We show that (i) the young outer stellar disc exhibits a flared distribution that is detectable in the height and vertical velocity distribution of A - and B -dwarf stars up to radii of ∼15 kpc, and (ii) the spin of the stellar halo out to 100 kpc can be accurately measured with Gaia DR2 RR Lyrae stars. These catalogues are well suited for comparisons with observations and should help to (i) develop and test analysis methods for the Gaia DR2 data, (ii) gauge the limitations and biases of the data, and (iii) interpret the data in the light of theoretical predictions from realistic ab initio simulations of galaxy formation in the ΛCDM cosmological model

Multidisciplinary, evidence-based consensus guidelines for human papillomavirus (HPV) vaccination in highrisk populations, Spain, 2016

Introduction: Although human papillomavirus (HPV) routine vaccination programmes have been implemented around the world and recommendations have been expanded to include other high-risk individuals, current recommendations often differ between countries in Europe, as well as worldwide. Aim: To find and summarise the best available evidence of HPV vaccination in high-risk patients aiding clinicians and public health workers in the day-to-day vaccine decisions relating to HPV in Spain. Methods: We conducted a systematic review of the immunogenicity, safety and efficacy/effectiveness of HPV vaccination in high-risk populations between January 2006 and June 2016. HPV vaccination recommendations were established with levels of evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Results: A strong recommendation about HPV vaccination was made in the following groups: HIV infected patients aged 9-26 years; men who have sex with men aged 9-26 years; women with precancerous cervical lesions; patients with congenital bone marrow failure syndrome; women who have received a solid organ transplant or hematopoietic stem cell transplantation aged 9-26 years; and patients diagnosed with recurrent respiratory papillomatosis. Conclusions: Data concerning non-routine HPV vaccination in populations with a high risk of HPV infection and associated lesions were scarce. We have developed a document to evaluate and establish evidence- based guidelines on HPV vaccination in highrisk populations in Spain, based on best available scientific evidence