Structural properties and Raman spectra of columbite-type NiNb2−x_{2-x}Vx_xO6_6 synthesized under high pressure

The complete set of structural parameters of the new series of compounds NiNb$_{2-x}$V$_x$O$_6$ ($0\leq x \leq 2$) with the unusual columbite-type structure is presented here. In the samples containing vanadium, this crystalline structure was stabilized by synthesis in conditions of high pressure and high temperature. Here we report here the first Raman spectrum for the NiV$_2$O$_6$-\textsl{Pbcn} polymorph and extend the list of the previously observed modes for the NiNb$_2$O$_6$. The evolution of the vibrational Raman spectrum produced when the vanadium is substituted for niobium along the series is also presented and discussed. This evolution is interpreted by taking into account the changes in the local structural environment of the niobium/vanadium atoms and its influence over the nickel-oxygen bonds around them. The presence of vanadium atoms favors an increase of the symmetry in the arrangement of oxygen atoms around the nickel-ones; in counterpart, the vanadium is in an octahedral environment which is more distorted than that of the niobium. Because of these apparently subtle differences, the homogeneous distribution of vanadium in the solid solution NiNb$_{2-x}$V$_x$O$_6$ is not possible

Producción y caracterización del nuevo sistema superconductor Yb0,5 Ho0,5Ba2,Cu3,O7

The characterization of the new superconductor system Yb0,5Ho0,5Ba2Cu3O7-ä belonging to the high temperature cuprates family TR123 is reported; the material was produced by the solid state reaction method (SSR) with a sintered temperature of 910 °C. The morphological characterization with respect to the granular behavior using the Scanning Electron Microscopy (SEM) technique is showed; the structural characterization is obtained submitting the specimen to X Rays Diffraction (DRX) and the structural parameters are got implementing the Rietveld refinement method in software GSAS; the material results to possess orthorhombic unitary cells type perovskite with a superconductor behavior which is evident on the resistivity as a function of the temperature curve whose derivate presents a critical point on the value of the critical temperature Tc 92,61 K.Se reporta la caracterizacion del nuevo sistema superconductor Yb0,5Ho0,5Ba2Cu3O7-� perteneciente a la familia de cupratos de alta temperatura TR123; el material fue producido utilizando el metodo de reaccion de estado solido (SSR) con una temperatura de sinterizado de 910 ��C. Se muestra la caracterizacion morfologica referente al comportamiento granular utilizando la tecnica de Microscopia electronica de barrido (SEM); la caracterizacion estructural, se logra sometiendo la muestra a difraccion de rayos X (DRX) y se obtienen los parametros estructurales implementando el metodo de refinamiento Rietveld en el software GSAS, el material resulta poseer celdas unitarias ortorrombicas tipo perovskita con un comportamiento superconductor que se evidencia en la curva de resistividad como funcion de la temperatura cuya derivada presenta un punto critico en el valor correspondiente a la temperatura critica Tc 92,61 K

Mortality after surgery in Europe: a 7 day cohort study

Background: Clinical outcomes after major surgery are poorly described at the national level. Evidence of heterogeneity between hospitals and health-care systems suggests potential to improve care for patients but this potential remains unconfirmed. The European Surgical Outcomes Study was an international study designed to assess outcomes after non-cardiac surgery in Europe.Methods: We did this 7 day cohort study between April 4 and April 11, 2011. We collected data describing consecutive patients aged 16 years and older undergoing inpatient non-cardiac surgery in 498 hospitals across 28 European nations. Patients were followed up for a maximum of 60 days. The primary endpoint was in-hospital mortality. Secondary outcome measures were duration of hospital stay and admission to critical care. We used χ² and Fisher’s exact tests to compare categorical variables and the t test or the Mann-Whitney U test to compare continuous variables. Significance was set at p<0·05. We constructed multilevel logistic regression models to adjust for the differences in mortality rates between countries.Findings: We included 46 539 patients, of whom 1855 (4%) died before hospital discharge. 3599 (8%) patients were admitted to critical care after surgery with a median length of stay of 1·2 days (IQR 0·9–3·6). 1358 (73%) patients who died were not admitted to critical care at any stage after surgery. Crude mortality rates varied widely between countries (from 1·2% [95% CI 0·0–3·0] for Iceland to 21·5% [16·9–26·2] for Latvia). After adjustment for confounding variables, important differences remained between countries when compared with the UK, the country with the largest dataset (OR range from 0·44 [95% CI 0·19 1·05; p=0·06] for Finland to 6·92 [2·37–20·27; p=0·0004] for Poland).Interpretation: The mortality rate for patients undergoing inpatient non-cardiac surgery was higher than anticipated. Variations in mortality between countries suggest the need for national and international strategies to improve care for this group of patients.Funding: European Society of Intensive Care Medicine, European Society of Anaesthesiology