903 research outputs found

    Local Site Behaviour in the 1976 Friuli Earthquake

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    Soon after the main shock of Friuli, Italy, May 6th 1976 earthquake, two strong motion recorders accelerographs were installed in two sites about 650 meters distant one from the other. One instrument was installed on hard outcropping rock, the other at the surface of an alluvial deposit 20+25 meters thick underlain by a sloping bedrock. Among the numerous records obtained three aftershocks of magnitude about 6 and hypocentral distance within 20 Km, are investigated by comparing maximum accelerations, durations, Arias intensity and Husid ratios. A new numerical tool is proposed which consists of a series of plots of the Husid ratios of low-pass filtered accelerograms. The numerical tool seems to be very promising since it allows to describe at the same time energy, duration and frequencies content, of a given ground motion. Moreover the application to the records simultaneously obtained at the two stations suggests that it would be more appropriate to define an accelerogram according to the type of behavior shown by the site during a certain earthquake rather than according to the local site characteristics like soft or hard

    Automatic induction of framenet lexical units in Italian

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    In this paper we investigate the applicability of automatic methods for frame induction to improve the coverage of IFrameNet, a novel lexical resource based on Frame Semantics in Italian. The experimental evaluations show that the adopted methods based on neural word embeddings pave the way for the assisted development of a large scale lexical resource for our language

    Deep view of the Subduction-Transform Edge Propagator (STEP) fault in the Calabrian Subduction Zone

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    The Calabrian Subduction Zone plays a key role in the evolution of the central Mediterranean in the framework of the convergence between Africa and Europe. Here, the remnants of the World’s oldest oceanic crust form a narrow NW-dipping slab passively subducting beneath the Calabrian Arc. Recently published high-resolution seismic profiles and bathymetric data of the western Ionian Sea highlight the presence of a NNW-SSE faulting system connected with a series of Plio-Pleistocene syn-tectonic basins. These features are correlated with the recent activity of a major NNW-SSE deformation zone confining the active subduction to the SW and interpreted as a Subduction-Transform Edge Propagator (STEP) fault. The goal of this work is to jointly reconstruct the geometry of the STEP fault and the subduction interface in its surroundings.We use multichannel seismic profiles acquired in the southwestern part of the Calabrian accretionary wedge to focus on the STEP fault geometry at depth and to analyse its relationships with shallow deformation features. The quantitative analysis and enhancement of seismic data provided an accurate image of the internal structure of the accretionary wedge at various depths, showing growth strata in the Plio-Pleistocene succession and major discontinuities in the lower crust. Our results depict a main subvertical, slightly east-dipping, lithospheric fault cutting the oceanic crust down to the Moho, and a rich set of associated secondary synthetic and antithetic faults. This picture also provides new insights on the STEP fault propagation mechanism. In addition, the tridimensional correlation of the STEP fault occurrences in various seismic profiles provides a preliminary scheme of its segmentation and highlights the relationships of this master fault with other main structural elements of the Calabrian Arc and Eastern Sicily, including some of the faults deemed to be responsible for major historical earthquakes in the area

    Deriving thrust fault slip rates from geological modeling: examples from the Marche coastal and offshore contraction belt, Northern Apennines, Italy.

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    We present a reconstruction of the central Marche thrust system in the central-northern Adriatic domain aimed at constraining the geometry of the active faults deemed to be potential sources of moderate to large earthquakes in this region and at evaluating their long-term slip rates. This system of contractional structures is associated with fault-propagation folds outcropping along the coast or buried in the offshore that have been active at least since about 3Myr. The ongoing deformation of the coastal and offshore Marche thrust system is associated with moderate historical and instrumental seismicity and recorded in sedimentary and geomorphic features. In this study, we use subsurface data coming from both published and original sources. These comprise cross-sections, seismic lines, subsurface maps and borehole data to constrain geometrically coherent local 3D geological models, with particular focus on the Pliocene and Pleistocene units. Two sections crossing five main faults and correlative anticlines are extracted to calculate slip rates on the driving thrust faults. Our slip rate calculation procedure includes a) the assessment of the onset time which is based on the sedimentary and structural architecture, b) the decompaction of clastic units where necessary, and c) the restoration of the slip on the fault planes. The assessment of the differential compaction history of clastic rocks eliminates the effects of compaction-induced subsidence which determine unwanted overestimation of slip rates. To restore the displacement along the analyzed structures, we use two different methods on the basis of the deformation style: the fault parallel flow algorithm for faulted horizons and the trishear algorithm for fault-propagation folds. The time of fault onset ranges between 5.3-2.2 Myr; overall the average slip rates of the various thrusts are in the range of 0.26-1.35 mm/yr

    The rna-binding ubiquitin ligase mex3a affects glioblastoma tumorigenesis by inducing ubiquitylation and degradation of rig-i

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    Glioblastoma multiforme (GB) is the most malignant primary brain tumor in humans, with an overall survival of approximatively 15 months. The molecular heterogeneity of GB, as well as its rapid progression, invasiveness and the occurrence of drug-resistant cancer stem cells, limits the efficacy of the current treatments. In order to develop an innovative therapeutic strategy, it is mandatory to identify and characterize new molecular players responsible for the GB malignant phenotype. In this study, the RNA-binding ubiquitin ligase MEX3A was selected from a gene expression analysis performed on publicly available datasets, to assess its biological and still-unknown activity in GB tumorigenesis. We find that MEX3A is strongly up-regulated in GB specimens, and this correlates with very low protein levels of RIG-I, a tumor suppressor involved in differentiation, apoptosis and innate immune response. We demonstrate that MEX3A binds RIG-I and induces its ubiquitylation and proteasome-dependent degradation. Further, the genetic depletion of MEX3A leads to an increase of RIG-I protein levels and results in the suppression of GB cell growth. Our findings unveil a novel molecular mechanism involved in GB tumorigenesis and suggest MEX3A and RIG-I as promising therapeutic targets in GB

    New results on focusing of gamma-rays with Laue lenses

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    We report on new results on the development activity of broad band Laue lenses for hard X-/gamma-ray astronomy (70/100-600 keV). After the development of a first prototype, whose performance was presented at the SPIE conference on Astronomical Telescopes held last year in Marseille (Frontera et al. 2008), we have improved the lens assembling technology. We present the development status of the new lens prototype that is on the way to be assembled.Comment: 8 pages, 11 figures, to be Published in SPIE Proceedings, vol.7437-19, 200

    UR 3.13 - MAXIMUM OBSERVABLE SHAKING (MOS) MAPS OF ITALY

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    The main goal of UR 3.13 is to establish a work flow for a multi-layer map that includes the seismicity of Italy in terms of Maximum Observable Shaking (MOS), and the near-field/far-field boundaries (NF/FF) with respect to the major seismogenic faults mapped within the DISS database. Here we will discuss only the procedure to derive the MOS-map of Italy. Our approach merges updated knowledge on the Italian regional tectonic setting and on the Source Zone (SZ) definition and broadband scenario-like calculation of expected maximum shaking on a given area. For a given SZ, broadband ground shaking is computed for a rupture model derived from a Maximum Credible Earthquake (MCE) and its associated Typical Fault (TF). Amplitude spectra for deterministic Low Frequency and stochastic High Frequency waveforms are reconciled at intermediate frequency, where their domain of validity overlaps, to derive broadband synthetics and compute the associated shaking. As the MCE and TF float along the SZ, broadband ground motion is computed at each point surrounding the given fault and the maximum among observable shaking according to that scenario is plotted on the MOS map. So far the procedure was entirely successfully tested on the Macro Region MR4 (central-northern Apennine), while more detailed analysis is done on the MCE and TF suggested for the Colfiorito earthquake. Here our broadband ground motion scenario shows, besides a complex pattern of variation, a southwestern area of high PGA values, at about 20 km distance from the fault, likely associated to with the properties of the spatio-temporal complexity of the rupture process. For the purpose of the project a complete new map of SZ and MCE is under compilation, grouping seismogenic sources according to Mw and faulting mechanisms. This goal can be achieved most efficiently by targeted numerical simulations that cover the parameter range of interest (in terms of magnitude and distance etc) and consider a large suite earthquake rupture scenarios

    The gamma-ray burst monitor for Lobster-ISS

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    Lobster-ISS is an X-ray all-sky monitor experiment selected by ESA two years ago for a Phase A study (now almost completed) for a future flight (2009) aboard the Columbus Exposed Payload Facility of the International Space Station. The main instrument, based on MCP optics with Lobster-eye geometry, has an energy passband from 0.1 to 3.5 keV, an unprecedented daily sensitivity of 2x10^{-12} erg cm^{-2}s$^{-1}, and it is capable to scan, during each orbit, the entire sky with an angular resolution of 4--6 arcmin. This X-ray telescope is flanked by a Gamma Ray Burst Monitor, with the minimum requirement of recognizing true GRBs from other transient events. In this paper we describe the GRBM. In addition to the minimum requirement, the instrument proposed is capable to roughly localize GRBs which occur in the Lobster FOV (162x22.5 degrees) and to significantly extend the scientific capabilities of the main instrument for the study of GRBs and X-ray transients. The combination of the two instruments will allow an unprecedented spectral coverage (from 0.1 up to 300/700 keV) for a sensitive study of the GRB prompt emission in the passband where GRBs and X-Ray Flashes emit most of their energy. The low-energy spectral band (0.1-10 keV) is of key importance for the study of the GRB environment and the search of transient absorption and emission features from GRBs, both goals being crucial for unveiling the GRB phenomenon. The entire energy band of Lobster-ISS is not covered by either the Swift satellite or other GRB missions foreseen in the next decade.Comment: 6 pages, 4 figures. Paper presented at the COSPAR 2004 General Assembly (Paris), accepted for publication in Advances in Space Research in June 2005 and available on-line at the Journal site (http://www.sciencedirect.com/science/journal/02731177), section "Articles in press
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