455 research outputs found
Recent inversion of the Tyrrhenian Basin
The Tyrrhenian Basin is a region created by Neogene extensional tectonics related to slab rollback of the east-southeast–migrating Apennine subduction system, commonly believed to be actively underthrusting the Calabrian arc. A compilation of >12,000 km of multichannel seismic profiles, much of them recently collected or reprocessed, provided closer scrutiny and the mapping of previously undetected large compressive structures along the Tyrrhenian margin. This new finding suggests that Tyrrhenian Basin extension recently ceased. The ongoing compressional reorganization of the basin indicates a change of the regional stress field in the area, confirming that slab rollback is no longer a driving mechanism for regional kinematics, now dominated by the Africa-Eurasia lithospheric collision
Profile of a new extended range-of-vision IOL: a laboratory study
Purpose To evaluate the surface profile of a new-generation extended range-of-vision intraocular lens (IOL) and to compare it with that obtained for a monofocal IOL based on the same platform. Methods Prospective, experimental, laboratory study comparing the surface profile of the DFT015 (AcrySof IQ Vivity; Alcon Laboratories, Inc.), a new-generation presbyopia-correcting IOL, with the profile of the SN60WF (AcrySof IQ; Alcon Laboratories, Inc.), an aspheric monofocal IOL based on the same platform. Raw profiles were obtained using contact profilometry. The best-fit form was then subtracted from each raw profile to highlight potential differences. Results No significant differences were appreciated in raw profiles. On the contrary, after form removal, the new extended range-of-vision IOL showed a peculiar profile characterized by the presence of two altitudinal symmetrical changes in the order of 1 µm, localized in the central portion of the optic. Conclusions The new-generation extended range-of-vision IOL evaluated showed a smooth change of its surface compared to the same platform monofocal IOL. The altitudinal changes blended in the central design of the new presbyopia-correcting IOL, although micrometric, might play a crucial role in creating a continuous focal range while minimizing visual disturbances.Open access funding provided by Università degli Studi di Trieste within the CRUI-CARE Agreement
In vivo antimicrobial activity of 0.6% povidone-iodine eye drops in patients undergoing intravitreal injections: a prospective study
To investigate the antimicrobial activity of a preservative-free 0.6% povidone-iodine eye drop as an antiseptic procedure in decreasing the conjunctival bacterial load in eyes scheduled for intravitreal treatment and to compare its efficacy to the untreated fellow eye used as the control group. Prospective cohort analysis in which 208 patients received preservative-free 0.6% povidone-iodine eye drops three times a day for three days before intravitreal injection. Before and after the prophylactic treatment, a conjunctival swab was collected from both the study eye and the untreated contralateral eye, used as control. The swab was inoculated on different culture media and the colony-forming units were counted. Bacteria and fungi were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Treatment with 0.6% povidone-iodine eye drops significantly reduced the conjunctival bacterial load from baseline (p < 0.001 for blood agar and p < 0.001 for chocolate agar) with an eradication rate of 80%. The most commonly isolated pathogen at each time-point and in both groups was coagulase-negative Staphylococci, isolated in 84% of the positive cultures. The study provides evidence about the effectiveness of 0.6% povidone-iodine eye drops treatment in reducing the conjunctival bacterial load in eyes scheduled for intravitreal treatment
Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network
We have studied the performance of a new algorithm for electron/pion
separation in an Emulsion Cloud Chamber (ECC) made of lead and nuclear emulsion
films. The software for separation consists of two parts: a shower
reconstruction algorithm and a Neural Network that assigns to each
reconstructed shower the probability to be an electron or a pion. The
performance has been studied for the ECC of the OPERA experiment [1].
The separation algorithm has been optimized by using a detailed Monte
Carlo simulation of the ECC and tested on real data taken at CERN (pion beams)
and at DESY (electron beams). The algorithm allows to achieve a 90% electron
identification efficiency with a pion misidentification smaller than 1% for
energies higher than 2 GeV
INFN What Next: Ultra-relativistic Heavy-Ion Collisions
This document was prepared by the community that is active in Italy, within
INFN (Istituto Nazionale di Fisica Nucleare), in the field of
ultra-relativistic heavy-ion collisions. The experimental study of the phase
diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP)
deconfined state will proceed, in the next 10-15 years, along two directions:
the high-energy regime at RHIC and at the LHC, and the low-energy regime at
FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the
present and future programme of the ALICE experiment, the upgrade of which will
open, in the 2020s, a new phase of high-precision characterisation of the QGP
properties at the LHC. As a complement of this main activity, there is a
growing interest in a possible future experiment at the SPS, which would target
the search for the onset of deconfinement using dimuon measurements. On a
longer timescale, the community looks with interest at the ongoing studies and
discussions on a possible fixed-target programme using the LHC ion beams and on
the Future Circular Collider.Comment: 99 pages, 56 figure
First events from the CNGS neutrino beam detected in the OPERA experiment
The OPERA neutrino detector at the underground Gran Sasso Laboratory (LNGS)
was designed to perform the first detection of neutrino oscillations in
appearance mode, through the study of nu_mu to nu_tau oscillations. The
apparatus consists of a lead/emulsion-film target complemented by electronic
detectors. It is placed in the high-energy, long-baseline CERN to LNGS beam
(CNGS) 730 km away from the neutrino source. In August 2006 a first run with
CNGS neutrinos was successfully conducted. A first sample of neutrino events
was collected, statistically consistent with the integrated beam intensity.
After a brief description of the beam and of the various sub-detectors, we
report on the achievement of this milestone, presenting the first data and some
analysis results.Comment: Submitted to the New Journal of Physic
Procedure for short-lived particle detection in the OPERA experiment and its application to charm decays
The OPERA experiment, designed to perform the first observation of oscillations in appearance mode through the detection of
the leptons produced in charged current interactions, has
collected data from 2008 to 2012. In the present paper, the procedure developed
to detect particle decays, occurring over distances of the order of 1 mm
from the neutrino interaction point, is described in detail. The results of its
application to the search for charmed hadrons are then presented as a
validation of the methods for appearance detection
Emulsion sheet doublets as interface trackers for the OPERA experiment
New methods for efficient and unambiguous interconnection between electronic
counters and target units based on nuclear photographic emulsion films have
been developed. The application to the OPERA experiment, that aims at detecting
oscillations between mu neutrino and tau neutrino in the CNGS neutrino beam, is
reported in this paper. In order to reduce background due to latent tracks
collected before installation in the detector, on-site large-scale treatments
of the emulsions ("refreshing") have been applied. Changeable Sheet (CSd)
packages, each made of a doublet of emulsion films, have been designed,
assembled and coupled to the OPERA target units ("ECC bricks"). A device has
been built to print X-ray spots for accurate interconnection both within the
CSd and between the CSd and the related ECC brick. Sample emulsion films have
been extensively scanned with state-of-the-art automated optical microscopes.
Efficient track-matching and powerful background rejection have been achieved
in tests with electronically tagged penetrating muons. Further improvement of
in-doublet film alignment was obtained by matching the pattern of low-energy
electron tracks. The commissioning of the overall OPERA alignment procedure is
in progress.Comment: 19 pages, 19 figure
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