Reversible enhancement of the magnetism of ultrathin Co films by H adsorption

By means of ab initio calculations, we have investigated the effect of H adsorption in the structural, electronic and magnetic properties of ultrathin Co films on Ru(0001). Our calculations predict that H occupies hollow sites preserving the two-dimensional 3-fold symmetry. The formation of a complete H overlayer leads to a very stable surface with strong H-Co bonds. H tends to suppress surface features, in particular, the enhancement of the magnetic moments of the bare film. The H-induced effects are mostly confined to the Co atoms bonded to H, independent of the H coverage or of the thickness and the structure of the Co film. However, for partial H coverages a significant increase occurs in the magnetic moment for the surface Co atoms not bonded to H, leading to a net enhancement of surface magnetism.Comment: 6 pages, 4 figures, 3 table

Interplay between the magnetic anisotropy contributions of Cobalt nanowires

We report on the magnetic properties and the crystallographic structure of the cobalt nanowire arrays as a function of their nanoscale dimensions. X-ray diffraction measurements show the appearance of an in-plane HCP-Co phase for nanowires with 50 nm diameter, suggesting a partial reorientation of the magnetocrystalline anisotropy axis along the membrane plane with increasing pore diameter. No significant changes in the magnetic behavior of the nanowire system are observed with decreasing temperature, indicating that the effective magnetoelastic anisotropy does not play a dominant role in the remagnetization processes of individual nanowires. An enhancement of the total magnetic anisotropy is found at room temperature with a decreasing nanowire diameter-to-length ratio (d/L), a result that is quantitatively analyzed on the basis of a simplified shape anisotropy model.Comment: 8 pages, 4 figure

Thermo-Optic Coefficient of Porous Silicon in the Infrared Region and Oxidation Process at Low Temperatures

In this work, a porous silicon nanostructure has been fabricated by electrochemical means and used as a thermal sensor. The thermo-optic effect in the near infrared region has been experimentally studied based on spectroscopy measurements. Values of the thermo-optic coefficient between 3.2 and 7.9·10^{-5} K^{-1} have been obtained, depending on the porosity, reaching a maximum thermal sensitivity of 91 ± 3 pm/°C during the experiments carried out with the fabricated samples. Additionally, the oxidation process of the sensor at temperatures below 500 K has been studied, showing that the growth of the silicon oxide was dependent on the characteristics of the porous layers. Based on the experimental results, a mathematical model was developed to estimate the evolution of the oxidation process as a function of porosity and thickness

Explanation and Elaboration Document for the STROBE-Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology—Veterinary Extension

The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was first published in 2007 and again in 2014. The purpose of the original STROBE was to provide guidance for authors, reviewers and editors to improve the comprehensiveness of reporting; however, STROBE has a unique focus on observational studies. Although much of the guidance provided by the original STROBE document is directly applicable, it was deemed useful to map those statements to veterinary concepts, provide veterinary examples and highlight unique aspects of reporting in veterinary observational studies. Here, we present the examples and explanations for the checklist items included in the STROBE-Vet Statement. Thus, this is a companion document to the STROBE-Vet Statement Methods and process document, which describes the checklist and how it was developed

Discovery of a wide companion near the deuterium burning mass limit in the Upper Scorpius association

We present the discovery of a companion near the deuterium burning mass limit located at a very wide distance, at an angular separation of 4.6+/-0.1 arcsec (projected distance of ~ 670 AU) from UScoCTIO108, a brown dwarf of the very young Upper Scorpius association. Optical and near-infrared photometry and spectroscopy confirm the cool nature of both objects, with spectral types of M7 and M9.5, respectively, and that they are bona fide members of the association, showing low gravity and features of youth. Their masses, estimated from the comparison of their bolometric luminosities and theoretical models for the age range of the association, are 60+/-20 and 14^{+2}_{-8} MJup, respectively. The existence of this object around a brown dwarf at this wide orbit suggests that the companion is unlikely to have formed in a disk based on current planet formation models. Because this system is rather weakly bound, they did not probably form through dynamical ejection of stellar embryos.Comment: 10 pages, including 4 figures and 2 table

Torrential rainfall in northeast of the Iberian Peninsula: synoptic patterns and WeMO influence

International audienceThis study presents a catalogue of synoptic patterns of torrential rainfall in northeast of the Iberian Peninsula (IP). These circulation patterns were obtained by applying a T-mode Principal Component Analysis (PCA) to a daily data grid (NCEP/NCAR reanalysis) at sea level pressure (SLP). The analysis made use of 304 days which recorded >100 mm in one or more stations in provinces of Barcelona, Girona and Tarragona (coastland area of Catalonia) throughout the 1950?2005 period. The catalogue comprises 7 circulation patterns showing a great variety of atmospheric conditions and seasonal or monthly distribution. Likewise, we computed the mean index value of the Western Mediterranean Oscillation index (WeMOi) for the synoptic patterns obtained by averaging all days grouped in each pattern. The results showed a clear association between the negative values of this teleconnection index and torrential rainfall in northeast of the IP. We therefore put forward the WeMO as an essential tool for forecasting heavy rainfall in northeast of Spain

Design of Allosteric Stimulators of the Hsp90 ATPase as New Anticancer Leads

Allosteric compounds that stimulate Hsp90 adenosine triphosphatase (ATPase) activity were rationally designed, showing anticancer potencies in the low micromolar to nanomolar range. In parallel, the mode of action of these compounds was clarified and a quantitative model that links the dynamic ligand-protein cross-talk to observed cellular and in vitro activities was developed. The results support the potential of using dynamics-based approaches to develop original mechanism-based cancer therapeutics

The constant-velocity highly collimated outflows of the planetary nebula He 2-90

We present high-dispersion echelle spectroscopic observations and a narrow-band [N II] image of the remarkable jet-like features of He 2-90. They are detected in the echelle spectra in the H-alpha and [N II] lines but not in other nebular lines. The [N II]/H-alpha ratio is uniformly high, ~1. The observed kinematics reveals bipolar collimated outflows in the jet-like features and shows that the southeast (northwest) component expands towards (away from) the observer at a remarkably constant line-of-sight velocity, 26.0+-0.5 km/s. The observed expansion velocity and the opening angle of the jet-like features are used to estimate an inclination angle of ~5 degrees with respect to the sky plane and a space expansion velocity of ~290 km/s. The spectrum of the bright central nebula reveals a profusion of Fe lines and extended wings of the H-alpha line, similar to those seen in symbiotic stars and some young planetary nebulae that are presumed to host a mass-exchanging binary system. If this is the case for He 2-90, the constant velocity and direction of the jets require a very stable dynamic system against precession and warping.Comment: 8 pages (emulate ApJ), 5 figure, 1 tabl