30 research outputs found
TRAVEL-TIME SOURCE SPECIFIC STATION CORRECTION IMPROVES LOCATION ACCURACY
Accurate earthquake locations are crucial for investigating seismogenic processes, as well as for applications like verifying compliance to the Comprehensive Test Ban Treaty (CTBT). Earthquake location accuracy is related to the degree of knowledge about the 3-D structure of seismic wave velocity in the Earth. It is well known that modeling errors of calculated travel times may have the effect of shifting the computed epicenters far from the real locations by a distance even larger than the size of the statistical error ellipses, regardless of the accuracy in picking seismic phase arrivals.
We have developed a method of seismic location to minimize this systematic shifts affecting hypocentral locations. These method is based on the fact that such shifts are quite similar for events for which the hypocenters are close to each other with respect to their distance from the recording stations. So this method is based on a set of Ground Truth events recorded by a dense local seismic network in seismically active regions.
The applications concern seismic sequences recorded in Italy and Iran.
We show that mislocations of the order of 10-20 km affecting the epicenters, as well as larger mislocations in hypocentral depths, calculated from a global seismic network can be effectively removed by applying source-specific station corrections applied to the standard IASPEI91 travel times.
This method is valid only for the area where calibration events are located but it is valid for any subset of the station network used for the calibration
Limnology for the ornithologist: effects of Lake Maggiore water level on migratory flows
Wetlands are widely recognised as the most critical stop-over locations along migration flyways. Wetland ecology is mostly influenced by water levels and water regimes. This research focuses on Bolle di Magadino (Switzerland), an important stop-over site on Lake Maggiore, artificially regulated by a dam. In this work we examined how the artificial flooding of a wetland affects the use of this stop-over site by migrating passerines during spring. Bird presence in the area was evaluated using both data collected at the ringing station located in the wetlands and the bird traffic rate (BTR) supplied by the BirdScan MR1, an avian vertical-looking radar (VLR) capable of automatically detecting and classifying birds in flight. In an attempt to shed light on the effect of lake level on stop- over quality, we i) simulated with GIS the extent of the flooded area and of the different habitat categories as the lake level changes; ii) calculated the relationship between lake level and the ability of stop-overing birds to acquire trophic resources; iii) verified that the flux of passerines below 500 m above ground level measured by radar could be used as a proxy for the number of stop-overing birds; iv) calculated the relationship between the number of birds leaving the stop-over and the lake level. While the number of ringed passerines has proven to be representative of the migratory flow below 500 meters of altitude at the site of interest, a high lake level seems to have a negative impact on the use by some species of the Bolle di Magadino area as a stop-over site during spring. In particular, two of the target species -the blackcap and the reed bunting- have proven to be sensitive to higher water levels. While taking into account the limitations and the relative nature of the results, could be necessary for the competent authorities to take these results into consideration in order to safeguard the Bolle di Magadino's role as an important stop- over area during spring
Primary Coenzyme Q10 Deficiency-Related Ataxias
Cerebellar ataxia is a neurological syndrome characterized by the imbalance (e.g., truncal ataxia, gait ataxia) and incoordination of limbs while executing a task (dysmetria), caused by the dysfunction of the cerebellum or its connections. It is frequently associated with other signs of cerebellar dysfunction, including abnormal eye movements, dysmetria, kinetic tremor, dysarthria, and/or dysphagia. Among the so-termed mitochondrial ataxias, variants in genes encoding steps of the coenzyme Q10 biosynthetic pathway represent a common cause of autosomal recessive primary coenzyme Q10 deficiencies (PCoQD)s. PCoQD is a potentially treatable condition; therefore, a correct and timely diagnosis is essential. After a brief presentation of the illustrative case of an Italian woman with this condition (due to a novel homozygous nonsense mutation in COQ8A), this article will review ataxias due to PCoQD
A Multidisciplinary Study of the DPRK Nuclear Tests
The Democratic People Republic of Korea announced two underground nuclear tests carried out in their territory respectively on October 9th, 2006 and May 25th, 2009. The scarce information on the precise location and the size of those explosions has stimulated various kinds of studies, mostly based on seismological observations, by several national agencies concerned with the Nuclear Test Ban Treaty verification. We analysed the available seismological data collected through a global high-quality network for the two tests. After picking up the arrival times at the various stations, a standard location program has been applied to the observed data. If we use all the available data for each single event, due to the different magnitude and different number of available stations, the locations appear quite different. On the contrary, if we use only the common stations, they happen to be only few km apart from each other and within their respective error ellipses. A more accurate relative location has been carried out by the application of algorithms such as double difference joint hypocenter determination (DDJHD) and waveform alignment. The epicentral distance between the two events obtained by these methods is 2 km, with the 2006 event shifted to the ESE with respect to that of 2009. We then used a dataset of VHR TerraSAR-X satellite images to detect possible surface effects of the underground tests. This is the first ever case where these highly performing SAR data have been used to such aim. We applied InSAR processing technique to fully exploit the capabilities of SAR data to measure very short displacements over large areas. Two interferograms have been computed, one co-event and one post-event, to remove possible residual topographic signals. A clear displacement pattern has been highlighted over a mountainous area within the investigated region, measuring a maximum displacement of about 45 mm overall the relief. Hypothesizing that the 2009 nuclear test had been carried out close to the area where the displacement has been observed through the DInSAR technique, its relation with the epicenter location obtained through seismological processing has been discussed as a possible alternative hypothesis with respect to the preferred solutions reported by the nuclear explosion database (NEDB). The distance of about 10 km between the two places can be considered acceptable in light of the possible systematic location shifts commonly observed in the seismological practice over a global scale. The difference between the m b magnitudes of the two tests could reflect differences in geological conditions of the two test sites, even if the yield of the two explosions had been the same
High-resolution aeromagnetic survey of Calabria (Southern Italy)
We present a 1:350,000 high-resolution magnetic anomaly map of Calabria (Southern Italy),
obtained by merging the results from two low-altitude aeromagnetic surveys performed in
southern and northern Calabria. Magnetic anomalies of Calabria are of low intensity, and
mostly range from 11 to â9 nT. Northern Calabria is characterized by positive anomalies in
the Tyrrhenian margin (Coastal Chain) that turn into negative values moving eastward in the
Sila Massif. Southern Calabria is characterized by slightly positive anomaly values, interrupted
by a null magnetic anomaly corridor roughly corresponding to the eastern margin of the
Gioia Tauro basin. Finally, anomaly values turn systematically negative in the Messina Straits.
Due to the unprecedented resolution (low flying height, spatial sampling along the flight line
of âŒ5 m and 1â2 km flight line spacing), the new map highlights, in detail, the geometry and
setting of the upper crustal features. As Calabria is one of the most seismically active regions
in Italy, hit by several high-magnitude earthquakes in recent centuries, the interpretation of
this new map will hopefully contribute to new insights into the crustal geological setting,
location and dimension of the main seismogenic sources.Published116-1231A. Geomagnetismo e Paleomagnetismo3SR. AMBIENTE - Servizi e ricerca per la SocietĂ JCR Journa
EMSO ERIC: A challenging infrastructure to monitor Essential Ocean Variables (EOVs) across European Seas
The European Multidisciplinary Seafoor and water Column Observatory (EMSO, www.emso.eu) is a distributed research infrastructure (RI), composed of fxed-point deep-sea observatories and shallow water test sites at strategic environmental locations from the southern entrance of the Arctic Ocean all the way through the North Atlantic through the Mediterranean to the Black Sea. Working as a single powerful system, it is a valuable new tool for researchers and engineers looking for long time series of high-quality and high-resolution data to study and continuously monitor complex processes interactions among the geosphere, biosphere, hydrosphere and atmosphere, as well as to test, validate and demonstrate new marine technologies.Peer Reviewe
Analysis of the Regional Ionosphere at Low Latitudes in Support of the Biomass ESA Mission
Biomass is a spaceborn polarimetric P-band (435 MHz) synthetic aperture radar (SAR) in a dawn-dusk low Earth orbit. Its principal objective is to measure biomass content and change in all the Earthâs forests. The ionosphere introduces Faraday rotation on every pulse emitted by low-frequency SAR and scintillations when the pulse traverses a region of plasma irregularities, consequently impacting the quality of the imaging. Some of these effects are due to Total Electron Content (TEC) and its gradients along the propagation path. Therefore, an accurate assessment of the ionospheric morphology and dynamics is necessary to properly understand the impact on image quality,
especially in the equatorial and tropical regions. To this scope, we have conducted an in-depth investigation of the significant noise budget introduced by the two crests of the Equatorial Ionospheric Anomaly (EIA) over Brazil and South-East Asia. The work is characterized by a novel approach to conceive a SAR-oriented ionospheric assessment, aimed at detecting and identifying spatial and temporal TEC gradients, including scintillation effects and Traveling Ionospheric Disturbances, by means of Global Navigation Satellite Systems (GNSS) ground-based monitoring stations. The novelty of this approach resides in the customization of the information about the impact of the ionosphere on SAR imaging as derived by local dense networks of ground instruments operating during the passes of Biomass spacecraft. The results identify the EIA crests as the regions hosting the bulk of irregularities potentially causing degradation on SAR imaging. Interesting insights about the local characteristics of low-latitudes ionosphere are also highlighted
EMSO ERIC: A challenging infrastructure to monitor Essential Ocean Variables (EOVs) across European Seas
Special issue 9th MARTECH: International Workshop on Marine Technology: 16-18 June 2021, Vigo, Spain.-- 2 pages, 1 figureThe European Multidisciplinary Seafoor and water Column Observatory (EMSO, www.emso.eu) is a distributed research infrastructure (RI), composed of fxed-point deep-sea observatories and shallow water test sites at strategic environmental locations from the southern entrance of the Arctic Ocean all the way through the North Atlantic through the Mediterranean to the Black Sea. Working as a single powerful system, it is a valuable new tool for researchers and engineers looking for long time series of high-quality and high-resolution data to study and continuously monitor complex processes interactions among the geosphere, biosphere, hydrosphere and atmosphere, as well as to test, validate and demonstrate new marine technologiesPeer reviewe
Sigh in patients with acute hypoxemic respiratory failure and acute respiratory distress syndrome: the PROTECTION pilot randomized clinical trial
Background: Sigh is a cyclic brief recruitment manoeuvre: previous physiological studies showed that its use could be an interesting addition to pressure support ventilation to improve lung elastance, decrease regional heterogeneity and increase release of surfactant.
Research question: Is the clinical application of sigh during pressure support ventilation (PSV) feasible?
Study design and methods: We conducted a multi-center non-inferiority randomized clinical trial on adult intubated patients with acute hypoxemic respiratory failure or acute respiratory distress syndrome undergoing PSV. Patients were randomized to the No Sigh group and treated by PSV alone, or to the Sigh group, treated by PSV plus sigh (increase of airway pressure to 30 cmH2Ofor 3 seconds once per minute) until day 28 or death or successful spontaneous breathing trial. The primary endpoint of the study was feasibility, assessed as non-inferiority (5% tolerance) in the proportion of patients failing assisted ventilation. Secondary outcomes included safety, physiological parameters in the first week from randomization, 28-day mortality and ventilator-free days.
Results: Two-hundred fifty-eight patients (31% women; median age 65 [54-75] years) were enrolled. In the Sigh group, 23% of patients failed to remain on assisted ventilation vs. 30% in the No Sigh group (absolute difference -7%, 95%CI -18% to 4%; p=0.015 for non-inferiority). Adverse events occurred in 12% vs. 13% in Sigh vs. No Sigh (p=0.852). Oxygenation was improved while tidal volume, respiratory rate and corrected minute ventilation were lower over the first 7 days from randomization in Sigh vs. No Sigh. There was no significant difference in terms of mortality (16% vs. 21%, p=0.342) and ventilator-free days (22 [7-26] vs. 22 [3-25] days, p=0.300) for Sigh vs. No Sigh.
Interpretation: Among hypoxemic intubated ICU patients, application of sigh was feasible and without increased risk