598 research outputs found

    Adapting integrity checking techniques for concurrent operation executions

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    One challenge for achieving executable models is preserving the integrity of the data. That is, given a structural model describing the constraints that the data should satisfy, and a behavioral model describing the operations that might change the data, the integrity checking problem consists in ensuring that, after executing the modeled operations, none of the specified constraints is violated. A multitude of techniques have been presented so far to solve the integrity checking problem. However, to the best of our knowledge, all of them assume that operations are not executed concurrently. As we are going to see, concurrent operation executions might lead to violations not detected by these techniques. In this paper, we present a technique for detecting and serializing those operations that can cause a constraint violation when executed concurrently , so that, previous incremental techniques, exploiting our approach, can be safely applied in systems with concurrent operation executions guaranteeing the integrity of the data.Peer ReviewedPostprint (author's final draft

    Characterization of >oil on copper> paintings by energy dispersive X-ray fluorescence spectrometry

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    Energy dispersive X-ray fluorescence is a common analytical tool for layer thickness measurements in quality control processes in the coating industry, but there are scarce microanalytical applications in order to ascertain semi-quantitative or quantitative information of painted layers. >Oil on copper> painting becomes a suitable material to be analysed by means of X-ray fluorescence spectrometry, due to the metallic nature of substrate and the possibility of applying layered models as used in coating industry. The aim of this work is to study the suitability of a quantitative energy dispersive X-ray fluorescence methodology for the assessment of the areal distribution of pigments and the characterization of painting methods on such kind of pictorial artworks. The method was calibrated using standard reference materials: dried droplets of monoelemental standard solutions laid on a metallic plate of copper. As an example of application, we estimated pigment mass distribution of two >oil on copper> paintings from the sixteenth and eighteenth centuries. Pictorial layers have been complementarily analysed by X-ray diffraction. Apart of the supporting media made of copper or brass, we could identify two different superimposed layers: (a) a preparation layer mainly composed by white lead and (b) the pictorial layer of variable composition depending on the pigments used by the artist on small areas of the painting surface. The areal mass distribution of the different elements identified in the painting pigments (Ca, Cr, Mn, Fe, Zn, Cd, Hg and Pb) have been determined by elemental mapping of some parts of the artworks. © 2011 Springer-Verlag.A. Pitarch gratefully acknowledges the Spanish Ministry of Education for the grant within the program of Formation of Graduate Stuff-FPU (reference AP2006-4591)Peer Reviewe

    Three-Dimensional Magnetotelluric Characterization of the Travale Geothermal Field (Italy)

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    The geoelectrical features of the Travale geothermal field (Italy), one of the most productive geothermal fields in the world, have been investigated by means of three-dimensional (3D) magnetotelluric (MT) data inversion. This study presents the first resistivity model of the Travale geothermal field derived from derivative-based 3D MT inversion. We analyzed MT data that have been acquired in Travale over the past decades in order to determine its geoelectrical dimensionality, directionality, and phase tensor properties. We selected data from 51 MT sites for 3D inversion. We carried out a number of 3D MT inversion tests by changing the type of data to be inverted, the inclusion of static-shift correction at some sites where new time-domain electromagnetic soundings (TDEM) were acquired, the grid rotation, as well as the starting model in order to assess the connection between the inversion model and the geology. The final 3D model herein presents deep elongated resistive bodies between the depths of 1.5 and 8 km. They are transverse to the Apennine structures and suggest a correlation with the strike-slip tectonics. Comparison with a seismic velocity model and well log data suggests a highly-fractured volume of rocks with vapor-dominated circulation. The outcome of this study provides new insights into the complex geothermal system of Travale

    Good-bye email, welcome Slack

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    [EN] Email is the standard in communication with university students; as a one-to-one communication device, students repeat their doubts along multiple messages, multiplying the teacher's work and preventing the participation and learning of other students. The topic forums on virtual campuses allow better a management of doubts but require the active participation of all the students to achieve a final outcome. We propose to abandon the email and traditional forums of the campuses and enter tools with a higher professional profile to manage communication with the students. The results of this first experience, carried out with more than 90 postgraduate students, encourage its mass employment in both undergraduate and postgraduate. The survey conducted over 102 students in three different subjects of two different MSc shows how Slack, the tool we used, has been highly valued, with differences depending on the studies but neither on the gender nor on the intensity of use of the social networks.Lopez-Zafra, JM.; De Paz-Cobo, S.; Queralt Sánchez, RA. (2020). Good-bye email, welcome Slack. En 6th International Conference on Higher Education Advances (HEAd'20). Editorial Universitat Politècnica de València. (30-05-2020):635-642. https://doi.org/10.4995/HEAd20.2020.11119OCS63564230-05-202

    Magnetotelluric Characterization of the Alhama de Murcia Fault (Eastern Betics) - Preliminary Results

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    The Lorca Earthquake (11/5/2011, Mw 5.2) stands as the most destructive in Spain over the last 50 years. It was interpreted as having occurred in an intersegment zone of the strike-slip Alhama de Murcia Fault (AMF). Within the research project “Intergeosima”, a multi parametric characterization and monitoring of the fault structure is ongoing, with the aim of developing a future Near Fault Observatory (NFO) to improve the understanding of the seismic behaviour of the fault in the short and medium term. In this work we present the preliminary results of a magnetotelluric (MT) survey carried out along the rambla de la Torrecilla (SW of Lorca). A more resistivity area might correspond to the Quaternary units, whereas the conductive areas might delineate the extent of the fault gauge materials. Further analysis and inversion of the data are necessary to obtain a more detailed picture of the extension and geometry below the fault zone

    A fluorescence microscopy-based protocol for volumetric measurement of lysolecithin lesion-associated de- and re-myelination in mouse brain

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    Lysolecithin injections into the white matter tracts of the central nervous system are a valuable tool to study remyelination, but evaluating the resulting demyelinating lesion size is challenging. Here, we present a protocol to consistently measure the volume of demyelination and remyelination in mice following brain lysolecithin injections. We describe serial sectioning of the lesion, followed by the evaluation of the demyelinated area in two-dimensional images. We then detail the computation of the volume using our own automated iPython script

    Functional Identification of Proteus mirabilis eptC gene encoding a Core Lipopolysaccharide Phosphoethanolamine Transferase

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    By comparison of the Proteus mirabilis HI4320 genome with known lipopolysaccharide (LPS) phosphoethanolamine transferases, three putative candidates (PMI3040, PMI3576, and PMI3104) were identified. One of them, eptC (PMI3104) was able to modify the LPS of two defined non-polar core LPS mutants of Klebsiella pneumoniae that we use as surrogate substrates. Mass spectrometry and nuclear magnetic resonance showed that eptC directs the incorporation of phosphoethanolamine to the O-6 of l-glycero-d-mano-heptose II. The eptC gene is found in all the P. mirabilis strains analyzed in this study. Putative eptC homologues were found for only two additional genera of the Enterobacteriaceae family, Photobacterium and Providencia. The data obtained in this work supports the role of the eptC (PMI3104) product in the transfer of PEtN to the O-6 of l,d-HepII in P. mirabilis strains

    The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

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    This work seeks to understand the kinetics of O2 and SO2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620 nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO2 consumption is favoured by low levels of SO2, by a low availability of free SO2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins
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