190 research outputs found

    Site effects of the Roio basin, L’Aquila

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    During the microzonation studies of the April 6th, 2009 L’Aquila earthquake, we observed local seismic amplifications in the Roio area—a plane separated from L’Aquila city center by mount Luco. Six portable, digital instruments were deployed across the plain from 15 April to mid-May 2009. This array recorded 152 aftershocks. We analyzed the ground motion from these events to determine relative site amplification within the plain and on surrounding ridges. Horizontal over vertical spectral ratio on noise data (HVSRN),aftershock recordings (HVEQ) and standard spectral ratio (SSR) showed amplifications at 1.3 and 4.0Hz on quaternary deposits. Seismic amplifications in the frequency range of 4 and 6Hz were also observed on a carbonate ridge of Colle di Roio, on the northwestern border of the plateau. A small amplification was noticed near the top of mount Luco, another rocky site. Large discrepancies in the amplification levels between methods have been observed for these sites, but the HVSRN, HVEQ and SSR gave similar results at the stations located in the Roio plain. On the rocky sites, the SSR was more reliable than the HVSRN at estimating the transfer function of the site, even if the resonance frequency seemed to be well detected by the latter method.Published809–8234.1. Metodologie sismologiche per l'ingegneria sismicaJCR Journalreserve

    Site effect variability of the Roio basin in the near-source area of the L'Aquila mainshock

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    In the frame of the microzonation studies of the April 6th, 2009 L'Aquila earthquake near-source area, we observed local seismic amplifications in the Roio area, a plain separated from L'Aquila city center by mount Luco. Six portable, digital instruments were deployed across the plain from the 15th of April until mid-May 2009. This array recorded up to 152 aftershocks. We analysed the ground motion from these events to determine relative site amplification within the plain and on the surrounding ridges. Horizontal over Vertical spectral ratio on noise data (HVSRN) and on aftershock recordings (HVEQ)as well as standard spectral ratio (SSR) show amplifications at 1.3 Hz and 4.0 Hz on the quaternary deposits. Seismic amplifications in the frequency range between 4 and 6 Hz were also observed on a carbonate ridge of Colle di Roio located on the northwest border of the plateau. A small amplification has also been noticed close to the top of mount Luco, another rocky site. This paper details the results we have obtained and addresses their interpretation.Submitted4.1. Metodologie sismologiche per l'ingegneria sismicaJCR Journalope

    OeBAS and CYP716C67 catalyze the biosynthesis of health-beneficial triterpenoids in olive (Olea europaea) fruits

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    center dot The bioactive properties of olive (Olea europaea) fruits and olive oil are largely attributed to terpenoid compounds, including diverse triterpenoids such as oleanolic, maslinic and ursolic acids, erythrodiol, and uvaol. They have applications in the agri-food, cosmetics, and pharmaceutical industries. Some key steps involved in the biosynthesis of these compounds are still unknown.center dot Genome mining, biochemical analysis, and trait association studies have been used to identify major gene candidates controlling triterpenoid content of olive fruits.center dot Here, we identify and functionally characterize an oxidosqualene cyclase (OeBAS) required for the production of the major triterpene scaffold beta-amyrin, the precursor of erythrodiol, oleanolic and maslinic acids, and a cytochrome P450 (CYP716C67) that mediates 2 alpha oxidation of the oleanane- and ursane-type triterpene scaffolds to produce maslinic and corosolic acids, respectively. To confirm the enzymatic functions of the entire pathway, we have reconstituted the olive biosynthetic pathway for oleanane- and ursane-type triterpenoids in the heterologous host, Nicotiana benthamiana. Finally, we have identified genetic markers associated with oleanolic and maslinic acid fruit content on the chromosomes carrying the OeBAS and CYP716C67 genes.center dot Our results shed light on the biosynthesis of olive triterpenoids and provide new gene targets for germplasm screening and breeding for high triterpenoid content

    Molecular evidence of Ureaplasma urealyticum and Ureaplasma parvum colonization in preterm infants during respiratory distress syndrome

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    BACKGROUND: Ureaplasma urealyticum and U. parvum have been associated with respiratory diseases in premature newborns, but their role in the pathogenesis of the respiratory distress syndrome (RDS) is unclear. The aim of this study was to detect, using molecular techniques, the role of Mycoplasma spp. and Ureaplasma spp. in respiratory secretion and blood specimens of preterm newborns with or without RDS and to evaluate the prevalence of perinatal U. urealyticum or U. parvum infection. The influence of chemotherapy on the clinical course was also evaluated. METHODS: Tracheal aspirate or nasopharingeal fluid samples from 50 preterm babies with (24) or without RDS (26) were analysed for detection of U. urealyticum and U. parvum by culture identification assay and PCR. Sequencing analysis of amplicons allowed us to verify the specificity of methods. Clarithromycin (10 mg kg(-1 )twice a day) was administered in ureaplasma-positive patients who presented clinical signs of RDS. RESULTS: 15/24 neonates with RDS (p < 0.001) and 4/26 without RDS were found PCR-positive for U. urealyticum or U. parvum. Culture identification assay was positive in 5/50 newborns, three of which with RDS. Sequencing analyses confirmed the specificity of these methods. Association of patent ductus arteriosus with ureaplasma colonization was more statistically significant (p = 0.0004) in patients with RDS than in those without RDS. CONCLUSION: Colonization of the lower respiratory tract by Ureaplasma spp. and particularly by U. parvum in preterm newborns was related to RDS. The routine use of molecular methods could be useful to screen candidate babies for etiologic therapy

    Seismic site response estimation in the near source region of the 2009 L'Aquila, Italy, Earthquake

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    To better estimate the seismic ground motion during the April 6th, 2009 earthquake in L'Aquila, we deployed temporary arrays in the near-source region. Several arrays have been successively set up in the Aterno valley's epicentral area and have recorded the aftershocks that followed the main shock, between April and September. The data has been processed in order to study the spectral ratios of the horizontal component of ground motion at the soil site and at a reference site, as well as the spectral ratio of the horizontal and the vertical movement at a single recording site. The results obtained confirm the presence of large amplification effects in both L'Aquila's historic centre and in the suburban areas. The resonance frequency has been found to be close to 0.6 Hz in downtown L'Aquila whereas the suburban areas show amplification at frequencies ranging from 2 Hz to 5 Hz.PublishedSkopje, Macedonia4.1. Metodologie sismologiche per l'ingegneria sismicaope

    The QE numerical simulation of PEA semiconductor photocathode

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    Several kinds of models have already been proposed for explaining the photoemission process. The exact photoemission theory of semiconductor photocathode was not well established after decades of research. In this paper an integral equation of quantum efficiency (QE) is constructed to describe the photoemission of positive electron affinity (PEA) semiconductor photocathode based on three-step photoemission model. The influences of forbidden gap, electron affinity, photon energy, incident angle, degree of polarization, refractive index, extinction coefficient, initial/final electron energy, relaxation time and external electric field on the QE of PEA semiconductor photocathode are taken into account. In addition, a computer code is also programmed to calculate the QE of K2CsSb photocathode theoretically at 532nm wavelength, the result is in line with the experimental value by and large. What are the reasons caused to the distinction between the experimental measuring and theoretical QE are discussed.Comment: 12 pages,3 figures,2 tables,submitted to Chinese Physics

    Memristive devices as a potential resistance standard

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    The EMPIR [1] project 20FUN06 MEMQuD --- “Memristive devices as quantum standard for nanometrology” [2] has as one of its fundamental goals the development of technical capability and scientific knowledge for the implementation of a quantum resistance standard based on memristive devices characterized by high scalability down to the nanometer scale, CMOS compatibility and working in air at room temperature. In this work it is presented an overview of the project and highlighted relevant characteristics and working principles of memristive devices, applications as well as the last revision of the International System of Units (SI) that is the motivation and background for the aim of this project

    Power tests of a PLD film MG photocathode in a RF gun

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    Metallic film photo-cathodes are rugged, have a fast response and good emission uniformity. Mg has also a relevant Quantum Efficiency (QE) in the near UV. A cathode suitable for a 1.5 cells S-band RF gun has been produced by depositing an Mg film on Cu by Pulsed Laser Deposition (PLD) technique. After different optimizations, stable good results have been reached in the low field measurement scenario. A sample was deposited on a gun flange and tested in the 1.6 cell injector at UCLA Pegasus facility to prove cathode resistance in a high field environment. The results are described
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