High resolution spectroscopy of the high velocity hot post-AGB star LS III +52 24 (IRAS 22023+5249)

The first high-resolution (R~50,000) optical spectrum of the B-type star, LS III +52 24, identified as the optical counterpart of the hot post-AGB candidate IRAS 22023+5249 (I22023) is presented. We report the detailed identifications of the observed absorption and emission features in the full wavelength range (4290-9015 A) as well as the atmospheric parameters and photospheric abundances (under the Local Thermodinamic Equilibrium approximation) for the first time. The nebular parameters (Te, Ne) are also derived. We estimate Teff=24,000 K, log g=3.0, xi=7 kms-1 and the derived abundances indicate a slightly metal-deficient evolved star with C/O<1. The observed P-Cygni profiles of hydrogen and helium clearly indicate on-going post-AGB mass loss. The presence of [N II] and [S II] lines and the non-detection of [O III] indicate that photoionisation has just started. The observed spectral features, large heliocentric radial velocity, atmospheric parameters, and chemical composition indicate that I22023 is an evolved post-AGB star belonging to the old disk population. The derived nebular parameters (Te=7000 K, Ne=1.2x104 cm-3) also suggest that I22023 may be evolving into a compact, young low-excitation Planetary Nebula. Our optical spectroscopic analysis together with the recent Spitzer detection of double-dust chemistry (the simultaneous presence of carbonaceous molecules and amorphous silicates) in I22023 and other B-type post-AGB candidates may point to a binary system with a dusty disk as the stellar origin common to the hot post-AGB stars with O-rich central stars.Comment: Accepted for publication in MNRAS (22 pages, 4 figures, and 8 tables). arXiv admin note: substantial text overlap with arXiv:0707.059

Room temperature ferromagnetic-like behavior in Mn-implanted and post-annealed InAs layers deposited by Molecular Beam Epitaxy

We report on the magnetic and structural properties of Ar and Mn implanted InAs epitaxial films grown on GaAs (100) by Molecular Beam Epitaxy (MBE) and the effect of Rapid Thermal Annealing (RTA) for 30 seconds at 750C. Channeling Particle Induced X- ray Emission (PIXE) experiments reveal that after Mn implantation almost all Mn atoms are subsbtitutional in the In-site of the InAs lattice, like in a diluted magnetic semiconductor (DMS). All of these samples show diamagnetic behavior. But, after RTA treatment the Mn-InAs films exhibit room-temperature magnetism. According to PIXE measurements the Mn atoms are no longer substitutional. When the same set of experiments were performed with As as implantation ion all of the layers present diamagnetism without exception. This indicates that the appearance of room-temperature ferromagnetic-like behavior in the Mn-InAs-RTA layer is not related to lattice disorder produce during implantation, but to a Mn reaction produced after a short thermal treatment. X-ray diffraction patterns (XRD) and Rutherford Back Scattering (RBS) measurements evidence the segregation of an oxygen deficient-MnO2 phase (nominally MnO1.94) in the Mn-InAs-RTA epitaxial layers which might be on the origin of room temperature ferromagnetic-like response observed.Comment: 16 pages, 5 figures. Acepted in J. Appl. Phy

Spontaneous Symmetry Breakdown in non-relativistic Quantum Mechanics

The advantages and disadvantages of some pedagogical non-relativistic quantum-mechanical models, used to illustrate spontaneous symmetry breakdown, are discussed. A simple quantum-mechanical toy model (a spinor on the line, subject to a magnetostatic interaction) is presented, that exhibits the spontaneous breakdown of an internal symmetry.Comment: 19 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1111.1213. Equations (30) and (31) have been corrected. Other minor correction

Winding number instability in the phase-turbulence regime of the Complex Ginzburg-Landau Equation

We give a statistical characterization of states with nonzero winding number in the Phase Turbulence (PT) regime of the one-dimensional Complex Ginzburg-Landau equation. We find that states with winding number larger than a critical one are unstable, in the sense that they decay to states with smaller winding number. The transition from Phase to Defect Turbulence is interpreted as an ergodicity breaking transition which occurs when the range of stable winding numbers vanishes. Asymptotically stable states which are not spatio-temporally chaotic are described within the PT regime of nonzero winding number.Comment: 4 pages,REVTeX, including 4 Figures. Latex (or postscript) version with figures available at http://formentor.uib.es/~montagne/textos/nupt

Chemical conversion treatments to protect biodegradable magnesium in applications as temporary implants for bone repair

7 páginas, 7 figuras, 1 tabla.[ES] El presente estudio se desarrolló para mejorar la resistencia a la corrosión del magnesio puro, modificando su superficie mediante recubrimientos de conversión química. Se generaron capas de carbonato y fluoruro por inmersión en soluciones de NaHCO3 al 9 % y de HF al 48 %, respectivamente. La resistencia a la corrosión de las muestras con recubrimiento se evaluó en comparación con la del sustrato desnudo mediante técnicas electroquímicas en una solución fisiológica (PBS). Los resultados obtenidos han mostrado que el recubrimiento de carbonato no es capaz de proteger de la degradación al sustrato de magnesio. Por el contrario, el recubrimiento de fluoruro ha demostrado aumentar, significativamente, la resistencia a la corrosión del magnesio en medio fisiológico. La alta compacidad y adherencia al sustrato metálico de la capa de MgF2 generada mediante este sencillo tratamiento de conversión química confieren al recubrimiento buenas propiedades protectoras.[EN] The present study was developed to improve the corrosion resistance of pure magnesium by applying chemical conversion coatings. Carbonate and fluoride layers were generated by immersion in solutions of NaHCO3 of concentration 9 wt.%and HF of concentration 48 wt.%, respectively. Corrosion resistance of the coated samples was evaluated in comparison with that of the uncoated substrate by electrochemical techniques in a physiological solution (PBS). Results have shown that the carbonate coating is not viable to be used for protecting magnesium against corrosion.On the contrary, the fluoridemagnesiumcoating significantly increases the corrosion resistance ofmagnesium in physiological medium. The high compactness and adherence to the base metal of theMgF2 layer produced by this simple chemical conversion treatment confer the protective properties to the coating.Los autores agradecen al MEC la financiación del proyecto con referencia MAT 2008-06719-C03-01. M. Carboneras agradece al CSIC la concesión de un contrato JAE-Doc.Peer reviewe

Las fuentes de financiación de las universidades públicas españolas

Las universidades públicas europeas mantienen desde hace décadas los presupuestos públicos como principal fuente de financiación, si bien en los últimos años se ha producido una ligera intensificación de los recursos privados. Las universidades públicas inglesas son las que, en mayor medida, han dado cabida a la financiación privada mediante el establecimiento de unas matrículas de las enseñanzas oficiale

Tuning the size, composition and structure of Au and Co50Au50 Nanoparticles by High-Power Impulse Magnetron Sputtering in gas-phase Synthesis

Gas-phase synthesis of nanoparticles with different structural and chemical distribution is reported using a circular magnetron sputtering in an ion cluster source by applying high-power impulses. The influence of the pulse characteristics on the final deposit was evaluated on Au nanoparticles. The results have been compared with the more common direct current approach. In addition, it is shown for the first time that high-power impulses in magnetron based gas aggregation sources allows the growth of binary nanoparticles, CoAu in this case, with a variety of crystalline and chemical arrangements which are analyzed at the atomic level

Probing 3D and NLTE models using APOGEE observations of globular cluster stars

Hydrodynamical (or 3D) and non-local thermodynamic equilibrium (NLTE) effects are known to affect abundance analyses. However, there are very few observational abundance testsof 3D and NLTE models. We developed a new way of testing the abundance predictions of 3D and NLTE models, taking advantage of large spectroscopic survey data. We use a line-by-line analysis of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectra (H band) with the Brussels Automatic Code for Characterizing High accUracy Spectra (BACCHUS). We compute line-by-line abundances of Mg, Si, Ca, and Fe for a large number of globular cluster K giants in the APOGEE survey. We compare this line-by-line analysis against NLTE and 3D predictions. While the 1D-NLTE models provide corrections in the right direction, there are quantitative discrepancies between different models. We observe a better agreement with the data for the models including reliable collisional cross-sections. The agreement between data and models is not always satisfactory when the 3D spectra are computed in LTE. However, we note that for a fair comparison, 3D corrections should be computed with self-consistently derived stellar parameters, and not on 1D models with identical stellar parameters. Finally, we focus on 3D and NLTE effects on Fe lines in the H band, where we observe a systematic difference in abundance relative to the value from the optical. Our results suggest that the metallicities obtained from the H band are more accurate in metal-poor giants. More atomic data and extended self-consistent 3D-NLTE computations need to be made. The method we have developed for testing 3D and NLTE models could be extended to other lines and elements, and is particularly suited for large spectroscopic surveys.Comment: 13 pages, 9 figures, accepted in A&

Nursing action in the management of pain, nausea and vomiting in pediatric patients with pump surgery of hypospadias continuous infusion for analgesia

Hipospadias, malformación congénita, fusión incompleta del pene con un meato uretral anómalo dificultando la micción normal; tratamiento quirúrgico, con colocación de un tutor vesical, resultando un postoperatorio doloroso, para lo cual se utilizan bombas de perfusión continua de analgesia (BPCA). Los datos fueron recogidos con una revisión de Historias Clínicas de 44 niños intervenidos en 2009, mediante una investigación cuantitativa, con realización de un estudio descriptivo; planteándose como objetivos: valorar la eficacia de la BPCA, valorar la eficacia del tratamiento de rescate, valorar la intervención de enfermería en la administración de las pautas de rescate. Entre los resultados destaca que el 63% de los niños son intervenidos entre 2 y 4 años, que el 69% portan BPCA tras ser intervenidos, que hasta 48 horas posquirúrgicas, el 84% de los niños permanecen con BPCA, que de las pautas de rescate por dolor, el 60% son fijas y el 40% “si dolor”, y en rescate por vómitos o náuseas, el 100% a “si vómitos o náuseas”. Como conclusión principal pensamos que los cambios producidos con la entrada en vigor de la Ley de garantías y uso racional de medicamentos y productos sanitarios, las enfermeras están capacitados, para indicar, usar y autorizar la dispensación de medicamentos sujetos a prescripción médica, y por tanto justificada la creación de un protocolo, que permita la realización de una prescripción colaborativa, teniendo como objetivo la optimización de los recursos sanitarios tanto humanos como materiales.Hypospadias, congenital malformation, incomplete fusion of the penis with an abnormal urethral meatus difficult urination normal, surgery with placement of a tutor bladder, resulting in a postoperative pain, for which continuous infusion pumps used for analgesia (BPCA). Data were collected by reviewing charts of 44 children operated on in 2009, through quantitative research with a study descriptive set as our objectives: to evaluate the effectiveness of the BPCA, assess the efficacy of salvage therapy, assess the nursing intervention in the administration of rescue guidelines. The results highlighted that 63% of children were operated on between 2 and 4 years, 69% carry the BPCA after being operated on, until 48 hours postsurgery, 84% of children remain with BPCA, which guidelines ransom for pain, 60% are fixed and 40% "Painless" and a ransom for vomiting or nausea, 100% a “if vomiting or nausea”. As a main conclusion we think that changes with the entry into force of the law on guarantees and rational use of medicines and medical devices, nurses are trained to show, use and authorize the dispensing of medical prescription drugs, and therefore justified the creation of a protocol, which allows the realization of a collaborative prescribing, aiming at the optimization of resources both human and material health

Llano Alto (Béjar-Salamanca) : aula activa de la naturaleza

Copia digital : Junta de Castilla y León. Consejería de Cultura y Turismo, 201