593 research outputs found
Studio delle possibilitĂ di utilizzo della costellazione Glonass nel suo stato
GLONASS (Global Navigation Satellite System) is a global position satellite system realized by ex-
Urss at the same time with the United Stateâs one. The first launch of satellites went back to 12th
October 1982, they completed constellation with 24 satellites in 1997. In the years Russia didnât
have economic force to maintain active the entire constellation. But in 2002 GLONASS relaunching
started, that provides 18 satellites before 2007, and it will reach 24 satellites before 2010. The
program provides the launch of three or two rockets a year, each one will bring to space two or three
satellite. At present (15th September 2006) there are 15 operative GLONASS satellites.
The aim of this work is to show the potentiality of the jointed use of GPS and GLONASS satellites
by performing an adequate subdivision of the observations collected during a survey in the area of
Rome using TOPCON receivers able to acquire data coming from both constellations
Tidal errors and deformations in regional GPS networks
At present, the tidal correction model described in the IERS 2003 Conventions should be applied in the processing of permanent networks: in brief, the model involves the computation of a first order tidal correction plus some corrective terms, as functions of space and time. In the BERNESE software, one of the main scientific softwares for GPS network processing, the IERS tidal model is implemented; in July 2004, a bug in the tidal correction routine was identified by one of the paper authors and corrected by the BERNESE staff: the error concerned a second order term, related to the semidiurnal tidal signal.
An experimental analysis on the error effects in the results stemming from processing of regional networks has been carried out. A network of 8 European permanent GPS stations has been selected: the network choice ensures heterogeneity in the length and the orientation of the baselines. One year of data has been considered and two elaborations of the data have been performed using the BERNESE 4.2 SW, by applying the same processing strategy and, respectively, the wrong (old) and the right (corrected) tidal correction routine. The differences in the network results and the deformations caused by the error are discussed
Water level and volume estimations of the Albano and Nemi lakes (central Italy)
In April 2006 an airborne laser scanning (LIDAR) survey of the Albano and Nemi craters was carried out to obtain
a high resolution digital terrain model (DTM) of the area. We have integrated the LIDAR survey of the
craters and the recent bathymetry of the Albano lake to achieve a complete DTM, useful for morphological studies.
In addition, with a GPS RTK survey (July 2007) we estimated the Albano and Nemi mean lake levels respectively
at 288.16 m and 319.02 m (asl). Based on the integrated DTM and the newly estimated water level
values, we evaluated about 21.7·106 m3 the water volume loss of the Albano lake from 1993 to 2007, with an
average rate of about 1.6·106 m3/yr
GPS Positioning and Velocity Field in the Apennines Subduction Zone
A stable geodetic reference frame permits to relate one position to another and to
compute a reliable deformation field from geodetic observations. In order to satisfy scientific
requirements, the reference frame should be accurate, reliable and internally consistent
over time with unambiguously specified datum definition (origin, scale, orientation and their
respective time evolution). Current reference frame stability between successive frame realizations
suggests that the agreement is at the level of 1 cm and 0.3 mm/yr respectively
for absolute and time derivative translation and scale factors. They represent the current
stability over time of the reference frame and set the sensitivity for geodetic measurements.
Here we will present the results of a GPS deformation field in the Italian region obtained
from all the available permanent GPS stations operated in Italy. The complex nature of the
ongoing tectonic deformation along the Alpine-Apennines orogenic systems is now evident and GPS data have proven its capability to measure millimetre scale deformations
Integrazione di rilievi batimetrici e laser scanner aereo nell'area dei Colli Albani
The Colli Albani are a Quaternary volcanic complex located about 15 km SE of Rome, comprised
in an area of latitudes 41.6-41.9 N and longitudes 12.5-12.9 E. It has recently developed particular
interest in the geophysical community for some peculiar characteristics imputable to a residual
volcanic activity.
In the framework of a project financed by the Department of the Civil Protection devoted to the
study of the Colli Albani deformations, we have recently realized a bathymetric survey of the
Albano lake and an airborne laser scanner survey of the Albano and Nemi craters.
The present work is composed by two phases. In a first phase the accuracy of the DEM achieved by
the laser scanner is verified through a comparison with a GPS kinematic survey. In particular, our
aim is to test if the use of DEM in different formats, TIN or Grid, could lead to meaningful
differences in terms of accuracy and precision. In a second phase of the work, we merged the
LIDAR and bathymetric data with the purpose to achieve a complete digital terrain model of the
area that could allow in the next future geo-morphological analyses of the whole volcanic structure
Sulodexide counteracts endothelial dysfunction induced by metabolic or non-metabolic stresses through activation of the autophagic program
OBJECTIVE: Endothelial dysfunction (ED) predisposes to venous thrombosis (VT) and post-thrombotic syndrome (PTS), a long-term VT-related complication. Sulodexide (SDX) is a highly purified glycosaminoglycan with antithrombotic, pro-fibrinolytic and anti-inflammatory activity used in the treatment of chronic venous disease (CVD), including patients with PTS. SDX has recently obtained clinical evidence in the âextension therapyâ after initial-standard anticoagulant treatment for the secondary prevention of recurrent deep vein thrombosis (DVT). Herein, we investigated how SDX counteracts ED. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVEC) were used. Metabolic and non metabolic-induced ED was induced by treating with methylglyoxal (MGO) or irradiation (IR), respectively. Bafilomycin A1 was used to inhibit autophagy. The production of reactive oxygen species (ROS), tetrazolium bromide (MTT) assay for cell viability, terminal de-oxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay for cell apoptosis, Real-time PCR and Western blot analysis for gene and protein expression were used. RESULTS: SDX protected HUVEC from MGO- or IR-induced apoptosis by counteracting the activation of the intrinsic and extrinsic caspase cascades. The cytoprotective effects of SDX resulted from a reduction in a) ROS production, b) neo-synthesis and release of pro-inflammatory cytokines (TNFα, IL1, IL6, IL8), c) DNA damage induced by MGO or IR. These effects were reduced when autophagy was inhibited. CONCLUSIONS: Data herein collected indicate the ability of SDX to counteract ED induced by metabolic or non-metabolic stresses by involving the intracellular autophagy pathway. Our experience significantly increases the knowledge of the mechanisms of action of SDX against ED and supports the use of SDX in the treatment of CVD, PTS and in the secondary prevention of recurrent DVT
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