Aportaciones al conocimiento de la flora muscinal del Pirineo Occidental

In this paper we give citations of 122 taxa of mosses, which have been collected in 31 sites in the Western Pyrenees, in Navarra (Northern Spain). 9 of them are new records to the moss flora of Navarra and 2 are new records both for Navarra and for all the Pyrenees. Some of the more noticeable novelties are Dicranum crassifolium Sérgio, Ochyra & Séneca, Orthotrichum acuminatum H. Phillib. and Orthotrichum shawii Wilson

Competition between electron and phonon excitations in the scattering of nitrogen atoms and molecules off tungsten and silver surfaces

We investigate the role played by electron-hole pair and phonon excitations in the interaction of reactive gas molecules and atoms with metal surfaces. We present a theoretical framework that allows us to evaluate within a full-dimensional dynamics the combined contribution of both excitation mechanisms while the gas particle-surface interaction is described by an ab-initio potential energy surface. The model is applied to study energy dissipation in the scattering of N$_2$ on W(110) and N on Ag(111). Our results show that phonon excitation is the dominant energy loss channel whereas electron-hole pair excitations represent a minor contribution. We substantiate that, even when the energy dissipated is quantitatively significant, important aspects of the scattering dynamics are well captured by the adiabatic approximation.Comment: 4pages and 3 figure

Non-adiabatic effects during the dissociative adsorption of O2 at Ag(111)? A first-principles divide and conquer study

We study the gas-surface dynamics of O2 at Ag(111) with the particular objective to unravel whether electronic non-adiabatic effects are contributing to the experimentally established inertness of the surface with respect to oxygen uptake. We employ a first-principles divide and conquer approach based on an extensive density-functional theory mapping of the adiabatic potential energy surface (PES) along the six O2 molecular degrees of freedom. Neural networks are subsequently used to interpolate this grid data to a continuous representation. The low computational cost with which forces are available from this PES representation allows then for a sufficiently large number of molecular dynamics trajectories to quantitatively determine the very low initial dissociative sticking coefficient at this surface. Already these adiabatic calculations yield dissociation probabilities close to the scattered experimental data. Our analysis shows that this low reactivity is governed by large energy barriers in excess of 1.1 eV very close to the surface. Unfortunately, these adiabatic PES characteristics render the dissociative sticking a rather insensitive quantity with respect to a potential spin or charge non-adiabaticity in the O2-Ag(111) interaction. We correspondingly attribute the remaining deviations between the computed and measured dissociation probabilities primarily to unresolved experimental issues with respect to surface imperfections.Comment: 18 pages including 6 figure

Non-reactive scattering of N2 from the W(110) surface studied with different exchange–correlation functionals

8 páginas, 8 figuras, 1 tabla.-- El Pdf del artículo es la versión post-print.The non-reactive scattering of N2 from the W(110) surface is studied with six dimensional (6D) classical dynamics and two distinct potential energy surfaces (PES). Here, we use the PESs calculated with density functional theory and two different exchange–correlation functionals, the PW91 [J. E. Perdew et al., Phys. Rev. B, 1992, 46, 6671] and the RPBE [B. Hammer et al., Phys. Rev. B, 1999, 59, 7413]. By analyzing the final rotational state and angular distributions, we extract information on the characteristics of the two PESs in the 6D configurational space. Comparison of the theoretical results with the available experimental data provides detailed information on the validity of each functional. In general, the PW91 PES is more corrugated than the RPBE one in all the configurational space, meaning that there is a stronger dependence of the potential energy on the molecular orientation and position over the surface unit cell. Furthermore, we find that the larger corrugation and the less repulsive character exhibited by the PW91 PES seems to be realistic at distances above the chemisorption well. In contrast, the less corrugated RPBE PES performs better in the region below the chemisorption well.This work has been supported in part by the Basque Departamento de Educación, Universidades e Investigación, the University of the Basque Country UPV/EHU (Grant No. IT-366-07) and the Spanish Ministerio de Ciencia e Innovación (Grant No. FIS2010-19609-C02-02).Peer reviewe

One-hundred aortic valve replacements in octogenarians: Outcomes and risk factors for early mortality

Background and aim of the study: Today, ageing of the western population is causing aortic valve surgery to be performed in elderly patients with increasing frequency. The study aim was to evaluate surgical outcome in octogenarian patients undergoing aortic valve replacement (AVR). Methods: A total of 100 patients (mean age 82.1 +/- 2.7 years; range: 80-95 years) who underwent AVR over a three-year period was reviewed. Concomitant coronary artery bypass grafting was performed in 34% of cases, and a bioprosthesis was implanted in 80%. The mean logistic EuroSCORE was 13.3%. Results: Operative mortality was 8.0%. In multivariate analysis, a logistic EuroSCORE >= 13.5% (p = 0.02), cross-clamp time >= 75 min (p = 0.02) and postoperative acute renal failure were predictors for in-hospital mortality. Follow up was 100% complete; the mean follow up period was 10.6 months. At one year after surgery, the actuarial survival rate of those patients who survived surgery was 86.1%. Postoperative dyspnea at one month (p = 0.004) was the only predictor of short-term mortality. Conclusion: Age in itself should not contraindicate surgery, and healthcare systems should be prepared to accommodate elderly patients who may require special resources

Vibrational deexcitation and rotational excitation of H2 and D2 scattered from Cu(111): Adiabatic versus non-adiabatic dynamics

The following article appeared in Journal of Chemical Physic 137.6 (2012): 064707 and may be found at http://scitation.aip.org/content/aip/journal/jcp/137/6/10.1063/1.4742907We have studied survival and rotational excitation probabilities of H2(vi = 1, Ji = 1) and D2(vi = 1, Ji = 2) upon scattering from Cu(111) using six-dimensional (6D) adiabatic (quantum and quasi-classical) and non-adiabatic (quasi-classical) dynamics. Non-adiabatic dynamics, based on a friction model, has been used to analyze the role of electron-hole pair excitations. Comparison between adiabatic and non-adiabatic calculations reveals a smaller influence of non-adiabatic effects on the energy dependence of the vibrational deexcitation mechanism than previously suggested by low-dimensional dynamics calculations. Specifically, we show that 6D adiabatic dynamics can account for the increase of vibrational deexcitation as a function of the incidence energy, as well as for the isotope effect observed experimentally in the energy dependence for H2(D2)/Cu(100). Furthermore, a detailed analysis, based on classical trajectories, reveals that in trajectories leading to vibrational deexcitation, the minimum classical turning point is close to the top site, reflecting the multidimensionally of this mechanism. On this site, the reaction path curvature favors vibrational inelastic scattering. Finally, we show that the probability for a molecule to get close to the top site is higher for H2 than for D2, which explains the isotope effect found experimentallyThis work has been financially supported by the DGI (Project Nos. FIS2010-15127 and FIS2010-19609-C02-02), the CAM (Project No. 2009/MAT1726), the Basque Dpto. de Educación, Universidades e Investigación, and the UPV/EHU (Project No. IT-366-07

Video-assisted mitral surgery through a micro-access: A safe and reliable reality in the current era

Background and aim of the study: Minimally invasive mitral valve surgery was introduced into clinical practice during the mid 1990s. The clinical benefits of the technique, namely a reduction of surgical trauma, increased patient comfort and shorter hospital stay, are achieved by using a video-assisted, mini-thoracotomy approach rather than a standard median sternotomy. Herein is described the authors' experience with video-assisted mitral surgery through a micro-access. Methods: Between September 2003 and September 2006, 100 patients (mean age 65.7 years; range: 16-84 years; 29 aged >75 years) underwent video-assisted port-access mitral valve surgery through a 4- to 6-cm anterior mini-thoracotomy. Mitral valve repair was carried out in 36 patients (36%) and mitral valve replacement (MVR) in 64 (64%) for degenerative (n = 54), rheumatic (n = 44), functional (n = 1) or infective disease (n = 1). Redo procedures were performed in 14 patients. Results: Peripheral extra-thoracic cardiopulmonary bypass (CPB) was used in all cases, and Endoclamp occlusion of the ascending aorta in 94%. The median intensive care unit and hospital stays were 20.0 +/- 30.8 h and 7.0 +/- 5.9 days, respectively. Hospital mortality was 4% (n = 4). No patient required conversion to sternotomy. Five patients (5%) underwent minimally invasive surgical revision for bleeding, and one patient (1%) had an early reoperation for MVR during the immediate postoperative course due to failure of a mitral valve repair. There were no perioperative myocardial infarctions, permanent strokes, major vascular complications, or peripheral ischemic events. Among the patients, 63% had no complications at all during the postoperative course, and no wound infections were observed. Conclusion: Video-assisted mitral surgery through a micro-access may be performed safely, at low risk of morbidity and mortality, and with results and quality standards similar to those reported for a sternotomy approach. Of note, older patients may be successfully treated using this technique

Femtosecond-laser induced dynamics of CO on Ru(0001): Deep insights from a hot-electron friction model including surface motion

Theoretical Chemistr