A low temperature X-ray single-crystal diffraction and polarised infra-red study of epidote

The effects of low-temperature on the crystal structure of a natural epidote [Ca1.925Fe0.745Al2.265Ti0.004 Si3.037O12(OH), a = 8.8924(7), b = 5.6214(3), c = 10.1547(6) angstrom and beta = 115.396(8)degrees at room conditions, Sp. Gr. P2(1)/m] have been investigated with a series of structure refinements down to 100 K on the basis of X-ray single-crystal diffraction data. The reflection conditions confirm that the space group is maintained within the T-range investigated. Structural refinements at all temperatures show the presence of Fe3+ at the octahedral M(3) site only [%Fe(M3) = 70.6(4)% at 295 K]. Only one independent proton site was located and two possible H-bonds occur, with O(10) as donor and O(4) and O(2) as acceptors. The H-bonding scheme is maintained down to 100 K and is supported by single crystal room-T polarised FTIR data. FTIR Spectra over the region 4,000-2,500 cm(-1) are dominated by the presence of a strongly pleochroic absorption feature which can be assigned to protonation of O(10)-O(4). Previously unobserved splitting of this absorption features is consistent with a NNN influence due to the presence of Al and Fe3+ on the nearby M(3) site. An additional relatively minor absorption feature in FTIR spectra can be tentatively assigned to protonation of O(10)-O(2). Low-T does not affect significantly the tetrahedral and octahedral bond distances and angles, even when distances are corrected for "rigid body motions". A more significant effect is observed for the bond distances of the distorted Ca(1)- and Ca(2)-polyhedra, especially when corrected for "non-correlated motion". The main low-T effect is observed on the vibrational regime of the atomic sites, and in particular for the two Ca-sites. A significant reduction of the magnitude of the thermal displacement ellipsoids, with a variation of U-eq (defined as one-third of the trace of the orthogonalised U-ij tensor) by similar to 40% is observed for the Ca-sites between 295 and 100 K. Within the same T-range, the U-eq of the octahedral and oxygen sites decrease similarly by similar to 35%, whereas those of the tetrahedral cations by similar to 22%

Using SPICES for a better service consumption

In this poster we present SPICES (Semantic Platform for the Interaction and Consumption of Enriched Services), a Web based tool that automates the process of consuming a Web service by making use of the semantic annotations that describe them. SPICES supports both traditional WSDL services and RESTful ones and offers end-users the possibility of interacting with them in an easy yet personalised manner, without the need of advanced technical skills -which were traditionally required-, being the complexity that lies underneath hidden to them. SPICES is being developed within the European project SOA4All

Organisational closure in biological organisms

International audienceThe central aim of this paper consists in arguing that biological organisms realize a specific kind of causal regime that we call "organisational closure"; i.e., a distinct level of causation, operating in addition to physical laws, generated by the action of material structures acting as constraints. We argue that organisational closure constitutes a fundamental property of biological systems since even its minimal instances are likely to possess at least some of the typical features of biological organisation as exhibited by more complex organisms. Yet, while being a necessary condition for biological organization, organisational closure underdetermines, as such, the whole set of requirements that a system has to satisfy in order to be taken as a paradigmatic example of organism. As we suggest, additional properties, as modular templates and control mechanisms via dynamical decoupling between constraints, are required to get the complexity typical of full-fledged biological organisms

Radio Loud AGN in the 2XMMi catalogue

We are carrying out a search for all radio loud Active Galactic Nuclei observed with XMM-Newton, including targeted and field sources to perform a multi-wavelength study of these objects. We have cross-correlated the Veron-Cetty & Veron (2010) catalogue with the XMM-Newton Serendipitous Source Catalogue (2XMMi) and found about 4000 matched sources. A literature search provided radio, optical, and X-ray data for 403 sources. Here we summarize the first results of our study.Comment: Proceedings og the IAU275 Symposium: Jets at all scale

An Organizational Account of Biological Functions

International audienceIn this paper, we develop an organizational account that defines biological functions as causal relations subject to closure in living systems, interpreted as the most typical example of organizationally closed and differentiated self-maintaining systems. We argue that this account adequately grounds the teleological and normative dimensions of functions in the current organization of a system, insofar as it provides an explanation for the existence of the function bearer and, at the same time, identifies in a non-arbitrary way the norms that functions are supposed to obey. Accordingly, we suggest that the organizational account combines the etiological and dispositional perspectives in an integrated theoretical framework

Biological organization and cross-generation functions

International audienceThe organizational account of biological functions interprets functions as contributions of a trait to the maintenance of the organization that, in turn, maintains the trait. As has been recently argued, however, the account seems unable to provide a unified grounding for both intra- and cross-generation functions, since the latter do not contribute to the maintenance of the same organization which produces them. To face this 'ontological problem', a splitting account has been proposed, according to which the two kinds of functions require distinct organizational definitions. In this article, we propose a solution for the ontological problem, by arguing that intra- and cross-generation functions can be said to contribute in the same way to the maintenance of the biological organization, characterized in terms of organizational self-maintenance. As a consequence, we suggest maintaining a unified organizational account of biological functions

High-pressure behaviour of zoisite

A high-pressure single-crystal X-ray diffraction (XRD) study has been carried out on two natural zoisite samples Ca 2Al 3-xFexSi 3O 12OH, one Fe-free (x = 0) and one Fe-rich (x = 0.12). The unit-cell parameters were determined for the Fe-free sample at 18 different pressures up to 7.76 GPa and for the Fe-rich sample at 13 different pressures up to 7.63 GPa. The P(V) data for both of the samples were fitted by a third-order Birch-Murnaghan equation of state (BM3 EoS). The equation of state coefficients are: V 0 = 903.39(5) \uc5 3, K T0 = 122.1(7) GPa, and K\u2032 0 = 6.8(2) for the Fe-free sample and V 0 = 906.95(5) \uc5 3, K T0 = 119.1(7) GPa, and K\u2032 0 = 7.3(2) for the Fe-rich sample. This shows that the addition of Fe in to the crystal structure of zoisite leads to a slight softening of the structure. Both compositions exhibit axial compressibilities \u3b2c > \u3b2 a 6b \u3b2 b, with the compressibilities of the a and b axes of the two samples being indistinguishable. The softening of the bulk modulus of zoisite with Fe content follows from softening of the c-axis of the structure. A high-pressure structural study of the Fe-free sample showed that the main compression mechanisms in the structure are the compression of soft inter-octahedral distance along [001] and soft intra-octahedral distances along [010] directions, while along [100] the main compression occurs because of the compression of stiff intra-octahedral distances. The substitution of Fe on to the M3 octahedral site of the structure leads to an increase of the intra-octahedral distance of the M3 that triggers the rotation of M12 and therefore leads to the softening of the M12 inter-octahedral distances that accounts for the softening of the c-axis of the structure

Elastic Thermobarometry

Upon exhumation and cooling, contrasting compressibilities and thermal expansivities induce differential strains (volume mismatches) between a host crystal and its inclusions. These strains can be quantified in situ using Raman spectroscopy or X-ray diffraction. Knowing equations of state and elastic properties of minerals, elastic thermobarometry inverts measured strains to calculate the pressure-temperature conditions under which the stress state was uniform in the host and inclusion. These are commonly interpreted to represent the conditions of inclusion entrapment. Modeling and experiments quantify corrections for inclusion shape, proximity to surfaces, and (most importantly) crystal-axis anisotropy, and they permit accurate application of the more common elastic thermobarometers. New research is exploring the conditions of crystal growth, reaction overstepping, and the magnitudes of differential stresses, as well as inelastic resetting of inclusion and host strain, and potential new thermobarometers for lower-symmetry minerals. A physics-based method is revolutionizing calculations of metamorphic pressures and temperatures. Inclusion shape, crystal anisotropy, and proximity to boundaries affect calculations but can be corrected for. New results are leading petrologists to reconsider pressure-temperature conditions, differential stresses, and thermodynamic equilibrium

Intrahepatic cholangiocarcinoma: review and update

Cholangiocarcinoma (CCA) is a heterogeneous group of malignancies that could develop at any level from the biliary tree. CCA is currently classified into intrahepatic (iCCA), perihilar and distal on the basis of its anatomical location. Of note, these three CCA subtypes have common features but also important inter-tumor and intra-tumor differences that can affect the pathogenesis and outcome. A unique feature of iCCA is that it recognizes as origin tissues, the hepatic parenchyma or large intrahepatic and extrahepatic bile ducts, which are furnished by two distinct stem cell niches, the canals of Hering and the peribiliary glands, respectively. The complexity of iCCA pathogenesis highlights the need of a multidisciplinary, translational and systemic approach to this malignancy. This review will focus on the advances of iCCA epidemiology, histo-morphology, risk factors, molecular pathogenesis, revealing the existence of multiple subsets of iCCA

"EosFit-Pinc: A simple GUI for host-inclusion elastic thermobarometry"—Reply to Zhong et al.

We provide a further algebraic proof that the lines of entrapment conditions for inclusions calculated with the formula of Guiraud and Powell (2006) are not thermodynamic isomekes and therefore do not represent exactly lines of possible entrapment conditions