Supersymmetric Kerr--anti-deSitter solutions

We prove the existence of one quarter supersymmetric type IIB configurations that arise as non-trivial scaling solutions of the standard five dimensional Kerr-AdS black holes by the explicit construction of its Killing spinors. This neutral, spinning solution is asymptotic to the static anti-deSitter space-time with cosmological constant $-\textstyle{\frac{1}{\ell^2}}$, it has two finite equal angular momenta $J_1=\pm J_2$, mass $M=\textstyle{\frac{1}{\ell}} (|J_1|+|J_2|)$ and a naked singularity.We also address the scaling limit associated with one half supersymmetric solution with only one angular momentum.Comment: 15 pages, no figure

Mesenchymal stem cells and their use as cell replacement therapy and disease modelling tool.

Mesenchymal stem cells (MSCs) from adult somatic tissues may differentiate in vitro and in vivo into multiple mesodermal tissues including bone, cartilage, adipose tissue, tendon, ligament or even muscle. MSCs preferentially home to damaged tissues where they exert their therapeutic potential. A striking feature of the MSCs is their low inherent immunogenicity as they induce little, if any, proliferation of allogeneic lymphocytes and antigen-presenting cells. Instead, MSCs appear to be immunosuppressive in vitro. Their multilineage differentiation potential coupled to their immuno-privileged properties is being exploited worldwide for both autologous and allogeneic cell replacement strategies. Here, we introduce the readers to the biology of MSCs and the mechanisms underlying immune tolerance. We then outline potential cell replacement strategies and clinical applications based on the MSCs immunological properties. Ongoing clinical trials for graft-versus-host-disease, haematopoietic recovery after co-transplantation of MSCs along with haematopoietic stem cells and tissue repair are discussed. Finally, we review the emerging area based on the use of MSCs as a target cell subset for either spontaneous or induced neoplastic transformation and, for modelling non-haematological mesenchymal cancers such as sarcomas

La Gran Recesión y el diferencial salarial por género en España

El artículo examina la evolución de las diferencias salariales entre hombres y mujeres en España entre los años 2002 y 2010. La evidencia obtenida sugiere que el notable empeoramiento de la coyuntura económica tras el inicio de la Gran Recesión ha tenido dos impactos reseñables sobre el diferencial salarial por razón de género. El primero es que se ha revertido la tendencia hacia la reducción de la brecha salarial por género que se venía produciendo en la economía española con anterioridad, durante la expansión económica. El segundo es que se ha generado un perfil creciente de la brecha salarial a lo largo de la distribución de salarios coincidente con el fenómeno de techo de cristal observado para otros países, pero no en períodos previos para España.This article examines the evolution of the gender wage gap in Spain between 2002 and 2010. The evidence suggests that the significant worsening of the economic situation after the onset of the Great Recession has had two significant impacts on the gap. The first is that it has reversed the trend towards the reduction of the gender pay gap in the Spanish economy during the previous economic expansion. The second is that it has generated a growing profile of the wage gap across the wage distribution which is consistent with the glass ceiling phenomenon observed for other advanced countries, but not in previous periods for Spain.Este trabajo se ha beneficiado de la financiación del proyecto de investigación CSO2011-29943-C03-02 del Ministerio de Educación, Cultura y Deporte

¿Sufren las mujeres inmigrantes una doble penalización salarial? Evidencia para España

El artículo examina los salarios relativos de las mujeres inmigrantes en España mediante la Encuesta de Estructura Salarial a través de una doble comparación con los hombres inmigrantes y las mujeres nativas. El análisis empírico muestra que las mujeres inmigrantes presentan desventajas salariales significativas frente a ambos colectivos. Los resultados de los ejercicios de descomposición de estas diferencias salariales permiten constatar que mientras que una parte importante de la desventaja salarial frente a los varones inmigrantes no resulta explicada por las diferencias en dotaciones de características productivas, por el contrario, la brecha salarial frente a las mujeres nativas es explicada en buena medida por este elemento. En consecuencia, la evidencia obtenida para España no concuerda plenamente con la hipótesis de la existencia de una doble penalización salarial para las mujeres inmigrantes.This study examines immigrant women relative wages in Spain as compared to those earned by immigrant men and native women on the basis of microdata from the Encuesta de Estructura Salarial. The results show that foreign-born women wages are significantly lower than those corresponding to both groups. It is also found that the wage gap compared to native women is explained largely by native women’s better endowments of productive characteristics whereas, on the contrary, a significant part of the wage disadvantage relative to male immigrants is not explained by this element. As a consequence, empirical evidence for the case of Spain does not seem to fully support the hypothesis of a double wage penalty for immigrant women.Este trabajo se ha beneficiado de la financiación del proyecto de investigación CSO2011-29943-C03-02 del Ministerio de Educación, Cultura y Deporte

B-type supergiants in the SMC: Rotational velocities and implications for evolutionary models

High-resolution spectra for 24 SMC and Galactic B-type supergiants have been analysed to estimate the contributions of both macroturbulence and rotation to the broadening of their metal lines. Two different methodologies are considered, viz. goodness-of-fit comparisons between observed and theoretical line profiles and identifying zeros in the Fourier transforms of the observed profiles. The advantages and limitations of the two methods are briefly discussed with the latter techniques being adopted for estimated projected rotational velocities (\vsini) but the former being used to estimate macroturbulent velocities. Only one SMC supergiant, SK 191, shows a significant degree of rotational broadening (\vsini $\simeq$ 90 \kms). For the remaining targets, the distribution of projected rotational velocities are similar in both our Galactic and SMC samples with larger values being found at earlier spectral types. There is marginal evidence for the projected rotational velocities in the SMC being higher than those in the Galactic targets but any differences are only of the order of 5-10 \kms, whilst evolutionary models predict differences in this effective temperature range of typically 20 to 70 \kms. The combined sample is consistent with a linear variation of projected rotational velocity with effective temperature, which would imply rotational velocities for supergiants of 70 \kms at an effective temperature of 28 000 K (approximately B0 spectral type) decreasing to 32 \kms at 12 000 K (B8 spectral type). For all targets, the macroturbulent broadening would appear to be consistent with a Gaussian distribution (although other distributions cannot be discounted) with an $\frac{1}{e}$ half-width varying from approximately 20 \kms at B8 to 60 \kms at B0 spectral types.Comment: 4 figures, 8 pages, submitted to Astronomy and Astrophysic

A Practical Guide for Predicting the Stereochemistry of Bifunctional Phosphoric Acid Catalyzed Reactions of Imines.

Chiral phosphoric acids have become powerful catalysts for the stereocontrolled synthesis of a diverse array of organic compounds. Since the initial report, the development of phosphoric acids as catalysts has been rapid, demonstrating the tremendous generality of this catalyst system and advancing the use of phosphoric acids to catalyze a broad range of asymmetric transformations ranging from Mannich reactions to hydrogenations through complementary modes of activation. These powerful applications have been developed without a clear mechanistic understanding of the reasons for the high level of stereocontrol. This Account describes investigations into the mechanism of the phosphoric acid catalyzed addition of nucleophiles to imines, focusing on binaphthol-based systems. In many cases, the hydroxyl phosphoric acid can form a hydrogen bond to the imine while the P═O interacts with the nucleophile. The single catalyst, therefore, activates both the electrophile and the nucleophile, while holding both in the chiral pocket created by the binaphthol and constrained by substituents at the 3 and 3' positions. Detailed geometric and energetic information about the transition states can be gained from calculations using ONIOM methods that combine the advantages of DFT with some of the speed of force fields. These high-level calculations give a quantitative account of the selectivity in many cases, but require substantial computational resources. A simple qualitative model is a useful complement to this complex quantitative model. We summarize our calculations into a working model that can readily be sketched by hand and used to work out the likely sense of selectivity for each reaction. The steric demands of the different parts of the reactants determine how they fit into the chiral cavity and which of the competing pathways is favored. The preferred pathway can be found by considering the size of the substituents on the nitrogen and carbon atoms of the imine electrophile, and the position of the nucleophilic site on the nucleophile in relation to the hydrogen-bond which holds it in the catalyst active site. We present a guide to defining the pathway in operation allowing the fast and easy prediction of the stereochemical outcome and provide an overview of the breadth of reactions that can be explained by these models including the latest examples.We are grateful to the EPSRC for a DTA award (J.P.R.).This is the author final version of the article. It first appeared from the American Chemical Society via http://dx.doi.org/10.1021/acs.accounts.6b0005