Multiple solid-phase microextraction in a non equilibrium situation. Application in quantitative analysis of chlorophenols and chloroanisoles related to cork taint in wine

Multiple HS-solid-phase microextraction (MHS-SPME) is a modification of SPME developed for quantitative analysis that avoids possible matrix effects based on an exhaustive analyte extraction from the sample. In this paper, the theory of this process associated with a non-equilibrium situation has been presented. The application of an optimised HS-SPME-based method in the analysis of chloroanisoles and chlorophenols, previously acetylated, associated with the occurrence of cork taint in different red, white and rosé wine samples, has revealed the existence of matrix effects. This fact determines the choice of standard addition as the adequate technique for the quantification of these compounds in real samples. MHS-SPME is proposed as a good alternative technique with respect to HS-SPME because it avoids matrix effects, simplifies the quantification of these compounds in real samples and reduces analysis time, providing sensitivity below chloroanisole sensory threshold with acceptable precision. © 2005 Elsevier B.V. All rights reserved

Polyacrylamide gel electrophoresis of humic and fulvic acids after acid hydrolysis

Two soil humic acids (HA), a marine sediment HA, and a soil fulvic acid (FA), were fractionated by polyacrylamide gel electrophoresis in the presence of denaturing agents before and after 6N HCl hydrolysis. After acid hydrolysis, the intensity of the high molecular size (MS) fraction decreased considerably in all HAs. On the other hand, a new high-MS fraction appeared in the FA after hydrolysis. The electrophoretic data indicate that acid hydrolysis produced a transformation in the humic macromolecule, inducing either depolymerization or condensation, depending on the nature of the humic fraction. Therefore, the advantages and disadvantages of using acid hydrolysis should be carefully considered before this treatment is carried out.Peer Reviewe

Ellipticals at z=0 from Self-Consistent Hydrodynamical Simulations: Clues on Age Effects in their Stellar Populations

We present results of a study of the stellar age distributions in the sample of elliptical-like objects (ELOs) identified at z=0 in four simulations operating in the context of a concordance cosmological model. The simulations show that the formation of most stars in each ELO of the sample is a consequence of violent dynamical events, either fast multiclump collapse at high z, or mergers at lower z. This second way can explain the age spread as well as the dynamical peculiarities observed in some ellipticals, but its relative weight is never dominant and decreases as the ELO mass at the halo scale, $M_{vir}$, increases, to such an extent that some recent mergers contributing an important fraction to the total ELO mass can possibly contribute only a small fraction of new born stars. More massive objects have older means and narrower spreads in their stellar age distributions than less massive ones. The ELO sample shows also a tight correlation between $M_{vir}$ and the central stellar l.o.s. velocity dispersion, $\sigma_{los}$. This gives a trend of the means and spreads of ELO stellar populations with $\sigma_{los}$ that is consistent, even quantitatively, with the age effects observationally detected in the stellar populations of elliptical galaxies. Therefore, these effects can be explained as the observational manifestation of the intrinsic correlations found in the ELO sample between $M_{vir}$ and the properties of the stellar age distribution, on the one hand, and $M_{vir}$ and $\sigma_{los}$, on the other hand. These correlations hint, for the first time, at a possible way to reconcile age effects in ellipticals, and, particularly, the increase of $\alpha /$ ratios with $\sigma_{los}$, with the hierarchical clustering paradigm.Comment: 13 pages, 2 figures, accepted for publication in Astrophysical Journal Letter

La Red de Ciencia y Tecnología para la Conservación del Patrimonio Cultural como plataforma de colaboración

13 páginas, 15 referencias.-- Jornada celebrada los días 24-25 de mayo de 2012, en el contexto de la VIII Bienal de la Restauración y Gestión del Patrimonio AR&PA 2012, en Valladolid.-- Las Jornadas Técnicas Arespa-Investigación y Empresa, han sido promovidas por la Delegación del CSIC en Castilla y León, la Red de Ciencia y Tecnología para la Conservación del Patrimonio Cultural (TechoHeritage) y la Asociación Española de Empresas de Restauración del Patrimonio Histórico (Arespa).El carácter multidisciplinar de la investigación en conservación del patrimonio cultural hace especialmente adecuado y necesario el establecimiento de redes que pongan en contacto y permitan la colaboración de los distintos actores implicados: universidades, centros de investigación, instituciones culturales y empresas. Con este fin, se creó en 2011 la Red TechnoHeritage (Red de Ciencia y Tecnología para la Conservación del Patrimonio Cultural), con la financiación del Ministerio de Economía y Competitividad. TechnoHeritage aglutina en la actualidad a 80 grupos de los ámbitos citados. En la presente publicación se presentan los orígenes de la Red, las motivaciones para su puesta en marcha, los objetivos que se pretenden alcanzar y algunas de las actividades que se han llevado a cabo.Al Ministerio de Economía y Competitividad por la financiación de la Red dentro del Programa de Acciones Complementarias del Plan Nacional de I+D+i 2008-2011 (HAR2010-11432-E).Peer reviewe

The Lack of Structural and Dynamical Evolution of Elliptical Galaxies since z ~ 1.5: Clues from Self-Consistent Hydrodynamical Simulations

We present results of a study on the evolution of the parameters characterizing the structure and dynamics of the relaxed elliptical-like objects (ELOs) identified at z=0, z=1 and z=1.5 in a set of hydrodynamical, self-consistent simulations operating in the context of a concordance cosmological model. The values of the stellar mass, the stellar half-mass radius and the stellar mean-square velocity have been measured in each ELO and found to populate, at any z, a flattened ellipsoid close to a plane (the dynamical plane, DP). Our simulations indicate that, at the intermediate zs considered, individual ELOs evolve, increasing the values of these parameters as a consequence of on-going mass assembly, but, nevertheless, their DP is roughly preserved within its scatter, in agreement with observations of the Fundamental Plane of ellipticals at different zs. We briefly discuss how this lack of significant dynamical and structural evolution in ELO samples arises, in terms of the two different phases operating in the mass aggregation history of their dark matter halos. According with our simulations, most dissipation involved in ELO formation takes place at the early violent phase, causing the stellar mass, the stellar half-mass radius and the stellar mean-square velocity parameters to settle down to the DP, and, moreover, the transformation of most of the available gas into stars. In the subsequent slow phase, ELO stellar mass growth preferentially occurs through non-dissipative processes, so that the DP is preserved and the ELO star formation rate considerably decreases. These results hint, for the first time, to a possible way of explaining, in the context of cosmological simulations, different apparently paradoxical observational results on ellipticals.Comment: 12 pages, 1 figure. Minor changes to match the published versio

Clues on Regularity in the Structure and Kinematics of Elliptical Galaxies from Self-consistent Hydrodynamical Simulations: the Dynamical Fundamental Plane

[Abridged] We have analysed the parameters characterising the mass, size and velocity dispersion both at the baryonic scale and at the halo scales of two samples of relaxed elliptical-like-objects (ELOs) identified, at z=0, in a set of self-consistent hydrodynamical simulations operating in the context of a concordance cosmological model. At the halo scale they have been found to satisfy virial relations; at the scale of the baryonic object the (logarithms of the) ELO stellar masses, projected stellar half-mass radii, and stellar central l.o.s. velocity dispersions define a flattened ellipsoid close to a plane (the intrinsic dynamical plane, IDP), tilted relative to the virial one, whose observational manifestation is the observed FP. The ELO samples have been found to show systematic trends with the mass scale in both, the relative content and the relative distributions of the baryonic and the dark mass ELO components, so that homology is broken in the spatial mass distribution (resulting in the IDP tilt), but ELOs are still a two-parameter family where the two parameters are correlated. The physical origin of these trends presumably lies in the systematic decrease, with increasing ELO mass, of the relative amount of dissipation experienced by the baryonic mass component along ELO stellar mass assembly. ELOs also show kinematical segregation, but it does not appreciably change with the mass scale. The non-homogeneous population of IDPs explains the role played by the virial mass to determine the correlations among intrinsic parameters. In this paper we also show that the central stellar line-of-sight velocity dispersion of ELOs, is a fair empirical estimator of the virial mass, and this explains the central role played by this quantity at determining the observational correlations.Comment: 20 pages, 17 Figures. Only changed to a more readable styl

Técnicas no destructivas para la monitorización cuantitativa y cualitativa de procesos de biodeterioro en materiales pétreos

7 páginas, 4 figuras, 1 tabla, 9 referencias. Trabajo presentado al IX Congresso Ibérico de Arqueometria, celebrado del 26-28, octubre, 2011, en Lisboa, Portugal[ES]: La colonización biológica de la piedra es uno de los principales problemas para la conservación de edificios y monumentos. El biodeterioro de la piedra ha sido estudiado empleando metodologías para la identificación de los microorganismos y para el seguimiento de su acción que, en su mayor parte necesitan de una gran inversión de tiempo y de un muestreo extensivo. Muchos de los procedimientos de muestreo empleados pueden, incluso, convertir a los propios investigadores en agentes de deterioro. En este estudio se propone el uso de técnicas para la detección temprana y monitorización de colonizaciones microbianas sin necesidad de contacto, como manera de contribuir al objetivo de preservar el patrimonio cultural.[EN]: Biological stone colonisation is one of the main problems related to the conservation of monuments and buildings. Stone biodeterioration has been assessed by several authors using time-consuming and extensive sampling methodologies for microbial identification and the follow-up of their action. However, most sampling procedures may convert the own researchers in deterioration agents. In this study the use of non-contact techniques for early detection and monitoring of microbial colonisations is proposed, as a contribution to the goal of the preservation of cultural heritage.AZM agradece a la Fundação para a Ciência e a Tecnologia - Ministério da Ciência, Tecnologia e Ensino Superior su beca postdoctoral (sfrh/bpd/63836/2009). Este estudio ha sido financiado parcialmente por el Centro de Petrologia e Geoquímica do Instituto Superior Técnico (CEPGIST) y por el proyecto CONSOLIDER TCP CSD2007-00058. Este trabajo ha sido cofinanciado con fondos FEDER.Peer reviewe

Laboratory and in situ assays of digital image analysis based protocols for biodeteriorated rock and mural paintings recording

8 pages, 8 figures, 43 references.Rock art paintings, and in general mural paintings, are one of the many elements of cultural heritage complex systems. As the different elements of a system have diverse spatial positions, spatial recording allows understanding their interactions. Thus, a useful approach to mural paintings recording is to understand it as a microcartography issue, managing each element of the system as a cartographic coverage. The approach implemented emphasizes the utilization of data obtained by remote sensing techniques for extracting different kinds of information susceptible of being analysed, classified and plotted in a differentiate way by means of the possibility of reducing redundant data by Principal Component Analysis (PCA) and the elaboration of false-colour images from uncorrelated bands. A laboratory model was prepared in order to simulate biodeterioration of rock art. The samples were photographically recorded thereafter under different lighting conditions, and PCA applied to the resulting images. False-colour images obtained by combining Principal Component bands allowed us to reach results similar to those of an unsupervised classification. The method has been applied to Roman mural paintings from one of the tombs of Carmona Necropolis, obtaining good results.Peer reviewe