1,526 research outputs found

    Studying the coincidence excess between EXPLORER and NAUTILUS during 1998

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    The coincidences between EXPLORER and NAUTILUS during 1998 (Astone et al. 2001) are more deeply studied. It is found that the coincidence excess is greater in the ten-day period 7-17 September 1998 and it occurs at the sidereal hour 4, when the detectors axes are perpendicular to the Galactic Disk. The purpose of this paper is to bring our results with the GW detectors to the attention of scientists working in the astrophysical field, and ask them whether are they aware of any special phenomenon occurring when EXPLORER and NAUTILUS showed a coincidence excess.Comment: 5 pages, 7 figures, submitted to A &

    Seismic vulnerability assessment on a territorial scale based on a Bayesian approach

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    Italian historical centres are mostly characterized by aggregate buildings. As defined by the Italian codes (Norme Tecniche per le Costruzioni 2008 and Circolare n. 617), the analysis of the most representative local mechanisms of collapse must be performed in order to assess their vulnerability. In this article, the out-of-plane local mechanisms of collapse analysis is implemented by applying a new method of analysis based on a probabilistic approach. Usually information which are necessary for the implementation of the local mechanisms analyses are affected by uncertainty or are missing, therefore in lots of cases it is only possible to hypothesize them on the basis of the other buildings information collected during the on-site survey. In this context, the implementation of a Bayesian approach allows to deduce buildings lacking information (i.e. wall thickness and interstorey height) starting from certain collected data (i.e. facades height). The historical centre of Timisoara (Romania) is selected as the case study for the implementation of this new method of analysis, given the extension of the on-site survey already carried out in the area (information about more than 200 structural units have been collected) and the seismic vulnerability assessment on an urban scale already performed by applying a traditional method. Results obtained by adopting the two approaches are then compared and a validation and a calibration of the new one is carried out

    The application of a Bayesian approach to assess the seismic vulnerability of historical centers

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    The seismic vulnerability of historical centers at a territorial scale cannot be assessed performing detailed analysis which are usually adopted at the single building scale. In fact, a traditional complete survey would be extremely time-consuming and not sustainable for this purpose. The approach described in this paper is based on the idea that it is possible to infer quantities which cannot be directly detected from buildings outside inspection starting from parameters that can be measured. In order to achieve this purpose, a Bayesian approach is applied, updating initial hypotheses when new data become available. In this context, the procedure herein proposed aims at applying a probabilistic approach instead of a deterministic one to define facades inter-storey height starting from buildings height knowledge. In order to validate the method, for out of plane local mechanisms of collapse (walls overturning), horizontal loads multiplier \uf0610 values are calculated and compared to results obtained by using data collected on-site

    transdermal 17 β estradiol and risk of developing type 2 diabetes in a population of healthy nonobese postmenopausal women

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    OBJECTIVE —Various observational and randomized studies have demonstrated a reduction in the incidence of type 2 diabetes in postmenopausal women who received estrogen orally. No studies have been performed on the incidence of type 2 diabetes in postmenopausal women treated with transdermal 17-β-estradiol. The purpose of our study was to assess the influence of transdermal 17-β-estradiol on the incidence of type 2 diabetes in a population of healthy, nonobese postmenopausal women. RESEARCH DESIGN AND METHODS —Between January 1998 and December 2002, 673 healthy, nonobese postmenopausal women (mean age 54 ± 5 years) were enrolled: 144 (21.4%) of these took transdermal 17-β-estradiol and 529 (78.6%) had never taken hormones during their postmenopausal period. Final elaboration of the data took place in July 2003, with a mean follow-up of 3.7 ± 0.7 years (ranging from 0.5 to 5 years). RESULTS —Type 2 diabetes developed in 60 patients during the follow-up period, which is the equivalent of 22 cases per 1,000 women-years. In the "hormones nonusers" group, diabetes developed in 10% (54 of 529 women; equivalent of 26.5 cases/1,000 women-years), whereas in the "hormones users" group, diabetes developed in 4.16% (6 of 144 women; equivalent of 12.1 cases/1,000 women-years). Transdermal 17-β-estradiol emerged as a treatment that significantly reduced the risk of developing diabetes (RR 2.19, 95% CI 1.79–3.56; P = 0.006). CONCLUSIONS —Our results suggest a significant reduction in the incidence of type 2 diabetes in our population of nonobese, healthy postmenopausal women who used transdermal 17-β-estradiol. This could suggest that, in some women, the estrogen deficiency that occurs after menopause could represent a fundamental step in the process of diabetogenesis

    Pounding Effects in Simply Supported Bridges Accounting for Spatial Variability of Ground Motion: A Case Study

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    This study carries out a parametrical analysis of the seismic response to asynchronous earthquake ground motion of a long multispan rc bridge, the Fener bridge, located on a high seismicity area in the north-east of Italy. A parametrical analysis has been performed investigating the influence of the seismic input correlation level on the structural response: a series of nonlinear time history analyses have been executed, in which the variation of the frequency content in the accelerograms at the pier bases has been described by considering the power spectral density function (PSD) and the coherency function (CF). In order to include the effects due to the main nonlinear behaviours of the bridge components, a 3D finite element model has been developed, in which the pounding of decks at cap-beams, the friction of beams at bearings, and the hysteretic behaviour of piers have been accounted for. The sensitivity analysis has shown that the asynchronism of ground motion greatly influences pounding forces and deck-pier differential displacements, and these effects have to be accurately taken into account for the design and the vulnerability assessment of long multispan simply supported bridges

    Dark Matter searches using gravitational wave bar detectors: quark nuggets and newtorites

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    Many experiments have searched for supersymmetric WIMP dark matter, with null results. This may suggest to look for more exotic possibilities, for example compact ultra-dense quark nuggets, widely discussed in literature with several different names. Nuclearites are an example of candidate compact objects with atomic size cross section. After a short discussion on nuclearites, the result of a nuclearite search with the gravitational wave bar detectors Nautilus and Explorer is reported. The geometrical acceptance of the bar detectors is 19.5 m2\rm m^2 sr, that is smaller than that of other detectors used for similar searches. However, the detection mechanism is completely different and is more straightforward than in other detectors. The experimental limits we obtain are of interest because, for nuclearites of mass less than 10−510^{-5} g, we find a flux smaller than that one predicted considering nuclearites as dark matter candidates. Particles with gravitational only interactions (newtorites) are another example. In this case the sensitivity is quite poor and a short discussion is reported on possible improvements.Comment: published on Astroparticle Physics Sept 25th 2016 replaced fig 1
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