467 research outputs found

    Mapping Moho depth variations in central Italy from PsMoho-P delay times: Evidence of an E-W transition in the Adriatic Moho at 42°N latitude

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    Along the Italian peninsula adjoin two crustal domains, peri-Tyrrhenian and Adriatic, whose boundary is not univocal in central Italy. In this area, we attempt to map the extent of the Moho in the two terrains from variations of the travel time difference between the direct P wave and the P-to-S wave converted at the crust-mantle boundary, called PsMoho. We use teleseismic receiver functions computed at 38 broad-band stations in this and previous studies, and assigned each of the recording sites to the Adriatic or peri-Tyrrhenian terrains based on station location, geologic and geophysical data and interpretation, and consistency of delays with the regional Moho trend. The results of the present study show that the PsMoho arrival time varies from 2.3 to 4.1 s in the peri-Tyrrhenian domain and from 3.7 to 5.5 s in the Adriatic domain. As expected, the lowest time difference is observed along the Tyrrhenian coastline and the largest values are observed in the axial zone of the Apennine chain. A key new result of this study is a sharp E-W boundary in the Adriatic domain that separates a deeper Moho north of about 42 N latitude from a shallower Moho to the south. This feature is constrained for a length of about 40 km by the observations available in this study. The E-W boundary requires a revision of prior mapping of the Moho in central Italy and supports previous hypotheses of lithosphere segmentation

    On the vacuum of the minimal nonsupersymmetric SO(10) unification

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    We study a class of nonsupersymmetric SO(10) grand unified scenarios where the first stage of the symmetry breaking is driven by the vacuum expectation values of the 45-dimensional adjoint representation. Three decade old results claim that such a Higgs setting may lead exclusively to the flipped SU(5) x U(1) intermediate stage. We show that this conclusion is actually an artifact of the tree level potential. The study of the accidental global symmetries emerging in various limits of the scalar potential offers a simple understanding of the tree level result and a rationale for the drastic impact of quantum corrections. We scrutinize in detail the simplest and paradigmatic case of the 45_{H} + 16_{H} Higgs sector triggering the breaking of SO(10) to the standard electroweak model. We show that the minimization of the one-loop effective potential allows for intermediate SU(4)_C x SU(2)_L x U(1)_R and SU(3)_c x SU(2)_L x SU(2)_R x U(1)_{B-L} symmetric stages as well. These are the options favoured by gauge unification. Our results, that apply whenever the SO(10) breaking is triggered by , open the path for hunting the simplest realistic scenario of nonsupersymmetric SO(10) grand unification.Comment: 22 pages, 1 figure. Refs added. To appear in Phys. Rev.

    Investigation of the Luco dei Marsi DSGSD revealing the first evidence of a basal shear zone in the central Apennine belt (Italy)

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    Deep-seated gravitational slope deformations (DSGSDs) show a wide range of geomorphological characteristics and kinematic behaviours. In many cases, deforming rock masses move on a continuous surface or a thick basal shear zone (BSZ) overlying the stable bedrock. The nature of this boundary is a significant issue in scientific debates since examples of BSZs have been observed or inferred in some DSGSDs worldwide. In the central Apennines, although several cases of DSGSDs have been described in recent decades, no evidence of BSZs has been documented thus far. This work presents the first case of a BSZ found in the region at the bottom of a large-scale gravitational deformation that affects the Mesozoic-Cenozoic carbonate ridge overhanging the Luco dei Marsi village (Abruzzi region). The BSZ consists of several metres-thick, cataclastic breccia developed within middle-Upper Cretaceous biodetritic limestone. The breccia level is exposed for approximately 200 m with a subhorizontal geometry and shows severe rock damage and weathering. The DSGSD hosting the BSZ affects an NNW-SSE-oriented and wide Miocene anticline whose eastern limb is dismembered by Pliocene-Quaternary normal faults delimiting the edge of a large Quaternary intermontane basin (the Fucino Basin). Field survey, aerial photointerpretation, and remote sensing (DInSAR technique) analyses outline an active gravity-driven process. This is characterized by several kinds of geomorphological features, including downhill- and uphill-facing scarps, ridge-top depressions, gravitational grabens and trenches in the upper and middle parts of the ridge, and bulging at the toe of the slope. These features, which can be distinguished from tectonic elements due to their shape and extension, are an indication of a high degree of internal deformation and a compound sagging geometry for the Luco dei Marsi DSGSD. The short-term activity of the process was revealed by DInSAR time series covering almost thirty years of satellite datasets, including ERS1/2, ENVISAT, COSMO-SkyMed, and SENTINEL 1 constellations. Strain rates on the order of a few mm/yr were inferred, with a marked difference between different sectors of the DSGSD area. The long-term (y > 102) lifespan of the DSGSD was framed into a multiple-step conceptual model summarizing the Early Pleistocene-Holocene geological evolution of the area. The model results outline the control exercised by extensional tectonics on DSGSD development, as progressive displacements along normal faults in the latest Pleistocene were the cause of lateral unconfinement at the toe of the slope. This work further contributes to the increasing knowledge on DSGSDs in the central Apennines and the understanding of the relationship between deformation features induced by slope morphogenesis, such as the BSZ, and Quaternary tectonics within the mountain belt

    Does the term 'trophic' actually mean anti-amyloidogenic? The case of NGF.

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    The term trophic is widely used to indicate a general pro-survival action exerted on target cells by different classes of extracellular messengers, including neurotrophins (NTs), a family of low-molecular-weight proteins whose archetypal member is the nerve growth factor (NGF). The pro-survival action exerted by NTs results from a coordinated activation of multiple metabolic pathways, some of which have only recently come to light. NGF has been shown to exert a number of different, experimentally distinguishable effects on neurons, such as survival, differentiation of target neurons, growth of nerve fibers and their guidance (tropism) toward the source of its production. We have proposed a more complete definition of the NGF trophic action that should also include its newly discovered property of inhibiting the amyloidogenic processing of amyloid precursor protein (APP), which is among the first hypothesized primary trigger of Alzheimer's disease (AD) pathogenesis. This inhibitory action appears to be mediated by a complex series of molecular events and by interactions among NGF receptors (TrkA and p75), APP processing and tau metabolic fate and fun

    Usefulness of transesophageal echocardiography in the assessment of aortic dissection

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    The acute dissection of the ascending aorta requires prompt and reliable diagnosis to reduce the high risk of mortality; in addition, prognosis is influenced by longterm complications. The aim of this article is to discuss transesophageal echocardiography (TEE) and (1) its diagnostic accuracy in the presurgical evaluation of patients, (2) its role in reducing time of diagnosis and surgery, and (3) its ability to reduce hospital mortality. TEE has also been tested as a screening method in the postsurgical follow-up of these patients. The retrospective investigation concerns a sample of 80 cases of acute dissection of the aorta, submitted for surgical intervention from April 1986 to February 1999. TEE has allowed a precise estimation of aortic diameters and optimal visualization of intimal flap and tear entry with a fine distinction between true and false lumen. A direct comparison of the results of TEE and of transthoracic echocardiography has demonstrated that some elements (visualization of flap and diameters in descending aorta, sites of entry and reentry, direction of let trough intimal tears, phasic intimal flap movement, diastolic collapse of flap on the valvular plane, false lumen thrombosis, coronary involvement, intramural hematoma, and aortic fissuration) were identified only by TEE, whereas other additional diagnostic elements (cardiac tamponade, aortic valve insufficiency, left ventricular function) show a similar pattern of significance. Routine employment of this method has confirmed a reduction of hospitalization time (about 1.5 hours of waiting time), and hospital mortality has changed from 42.8% to 17.3%. In the follow-up of patients operated on for aortic dissection, fundamental information may be obtained from TEE (assessment of the progression of thrombosis in the false lumen with its complete obliteration and modifications in aortic diameter with a consequent, possible worsening of aortic valve insufficiency). In conclusion, our study demonstrated that TEE may provide fast and efficient detection of acute aortic dissection. In the postsurgical follow-up, TEE has confirmed detection of major complications that can influence long-term prognosis and may be proposed as a method with easy access-one that is repeatable and inexpensive for the screening of aortic dissection surgical patients. (C) 2000 by Excerpta Medica, Inc

    An Electrically Conductive Oleogel Paste for Edible Electronics

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    Edible electronics will facilitate point-of-care testing through safe devices digested/degraded in the body/environment after performing a specific function. This technology, to thrive, requires a library of materials that are the basic building blocks for eatable platforms. Edible electrical conductors fabricated with green methods and at a large scale and composed of food derivatives, ingestible in large amounts without risk for human health are needed. Here, conductive pastes made with materials with a high tolerable upper intake limit (≥mg kg−1 body weight per day) are proposed. Conductive oleogel composites, made with biodegradable and food-grade materials like natural waxes, oils, and activated carbon conductive fillers, are presented. The proposed pastes are compatible with manufacturing processes such as direct ink writing and thus are suitable for an industrial scale-up. These conductors are built without using solvents and with tunable electromechanical features and adhesion depending on the composition. They have antibacterial and hydrophobic properties so that they can be used in contact with food preventing contamination and preserving its organoleptic properties. As a proof-of-principle application, the edible conductive pastes are demonstrated to be effective edible contacts for food impedance analysis, to be integrated, for example, in smart fruit labels for ripening monitoring

    PREDICTING THE LONG-TERM PERFORMANCE OF STRUCTURES MADE WITH ADVANCED CEMENT BASED MATERIALS IN EXTREMELY AGGRESSIVE ENVIRONMENTS: CURRENT STATE OF PRACTICE AND RESEARCH NEEDS – THE APPROACH OF H2020 PROJECT RESHEALIENCE.

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    Recently, in the framework of H2020, the European Commission has funded the project ReSHEALience (www.uhdc.eu), whose main goal is to develop an Ultra High Durability Concrete (UHDC) and a Durability Assessment-based Design (DAD) methodology for structures, to improve durability and predict their long-term performance under Extremely Aggressive Exposures. The project, coordinated by Politecnico di Milano, gathers 14 partners from 8 different countries (Italy, Spain, Estonia, Germany, Greece, Ireland, Israel, Malta), including 6 academic and research institutions together with 8 industrial partners, which cover the whole value chain, from producers of concrete constituents to construction companies to stake-holders and end-users. A key activity of the project will consist in the development of a theoretical model to evaluate ageing and degradation of UHDC structures, extending the modelling to predict the lifespan, and its incorporation in a Durability Assessment-based Design (DAD) methodology, which will be validated against experimental tests performed in the same project and the monitored performance of six full-scale pilots in real exposure conditions. The paper, starting from a review of the current state of art on the modelling of advanced cement based materials in extremely aggressive environments (EAE), will address the approach pursued in the project

    First results from the CROP-11 deep seismic profile, central Apennines, Italy: evidence of mid-crustal folding

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    The CROP-11 deep seismic profile across the central Apennines, Italy, reveals a previously unknown, mid-crustal antiform here interpreted as a fault-bend fold-like structure. The seismic facies and gravity signature suggest that this structure consists of low-grade metamorphic rocks. Geomorphological, stratigraphic and tectonic evidence in the overlying shallow thrusts suggests that this structure developed in early to mid-Messinian time and grew out of sequence in late Messinian– Pliocene time. The out-of-sequence growth may reflect a taper subcriticality stage of the Apenninic thrust wedge, which induced renewed contraction in the rear.Published583–586ope
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