745 research outputs found
Surface deformation of active volcanic areas retrieved with the SBAS-DInSAR technique: an overview
This paper presents a comprehensive overview of the surface deformation retrieval capability of the Differential
Synthetic Aperture Radar Interferometry (DInSAR) algorithm, referred to as Small BAseline Subset (SBAS)
technique, in the context of active volcanic areas. In particular, after a brief description of the algorithm some
experiments relevant to three selected case-study areas are presented. First, we concentrate on the application of
the SBAS algorithm to a single-orbit scenario, thus considering a set of SAR data composed by images acquired
on descending orbits by the European Remote Sensing (ERS) radar sensors and relevant to the Long Valley
caldera (eastern California) area. Subsequently, we address the capability of the SBAS technique in a multipleorbit
context by referring to Mt. Etna volcano (southern Italy) test site, with respect to which two different ERS
data set, composed by images acquired both on ascending and descending orbits, are available. Finally, we take
advantage of the capability of the algorithm to work in a multi-platform scenario by jointly exploiting two different
sets of SAR images collected by the ERS and the Environment Satellite (ENVISAT) radar sensors in the
Campi Flegrei caldera (southern Italy) area. The presented results demonstrate the effectiveness of the algorithm
to investigate the deformation field in active volcanic areas and the potential of the DInSAR methodologies within
routine surveillance scenario
Modeling of the acute toxicity of benzene derivatives by complementary QSAR methods
A data set containing acute toxicity values (96-h LC50) of 69 substituted benzenes for fathead minnow (Pimephales promelas) was investigated with two Quantitative Structure- Activity Relationship (QSAR) models, either using or not using molecular descriptors, respectively. Recursive Neural Networks (RNN) derive a QSAR by direct treatment of the molecular structure, described through an appropriate graphical tool (variable-size labeled rooted ordered trees) by defining suitable representation rules. The input trees are encoded by an adaptive process able to learn, by tuning its free parameters, from a given set of structureactivity training examples. Owing to the use of a flexible encoding approach, the model is target invariant and does not need a priori definition of molecular descriptors. The results obtained in this study were analyzed together with those of a model based on molecular descriptors, i.e. a Multiple Linear Regression (MLR) model using CROatian MultiRegression selection of descriptors (CROMRsel). The comparison revealed interesting similarities that could lead to the development of a combined approach, exploiting the complementary characteristics of the two approaches
The VELISAR initiative for the measurement of ground velocity in italian seismogenic areas
VELISAR (Ground VELocity in Italian Seismogenic Areas) is a scientific research
initiative aimed at producing a map of the ground deformation over most of the seismogenic
areas of Italy, using the space-based technique of multitemporal Synthetic
Aperture Radar Interferometry (InSAR). The ground velocities derived from InSAR
data will be validated by means of ground based data obtained from GPS, optical leveling,
seismological and neotectonic studies. The scope of the project is to produce
a high-resolution ground deformation dataset useful to model the seismic cycle of
strain accumulation and release at the scale of the single faults. The main objective of
VELISAR is to produce maps of ground velocity with the following characteristics:
- A ground resolution better than 100 m. - Average uncertainty of LoS velocity measurements
smaller than 2 mm/yr . - Temporal coverage of at least 7 years. - Retrieval
of East and Up components from ascending and descending LoS.
VELISAR will exploit the potential of the long time series (1992-2000) of ERS InSAR
data maintained in the ESA archives; over 4000 ERS images will have to be processed
to accomplish its objectives. Presently, two InSAR techniques for the measurement
of slow ground deformation are used in VELISAR: the Permanent Scatterers (PS)
technique developed by the Politecnico of Milano (POLIMI), and the Small Baseline
Subset (SBAS) technique, developed by the Institute for Remote Sensing of Environment
(IREA-CNR), in Napoli. The PS technique is applied by TRE preferably over
areas characterised by diffuse temporal decorrelation due to, for instance, erodible
lithologies, agricultural land use and strong vegetation cover. In these areas we expect
to obtain good temporal coherence mainly on sparse point scatterers. The SBAS
technique is applied by IREA and INGV mostly over areas where limited temporal
decorrelation is expected: urban areas, scarcely vegetated areas. The ground resolution
at which these data are originally processed is 80 m. An important goal of the
VELISAR initiative is to disseminate the information on the InSAR-derived ground
velocity measurements, to the scientific community and to the public in general. Such
goal is accomplished through a dedicated web site, where the velocity maps of the
italian seismogenic areas will be progressively published. We will present the initiative,
its scope and objectives, the technical details and the data processing strategies,
and some examples of ground velocity maps.PublishedVienna, Austriaope
FIFTEEN YEARS OF ERS AND ENVISAT DInSAR OBSERVATIONS AT MT. ETNA (ITALY) BY USING THE SBAS APPROACH
We exploited the Small BAseline Subset (SBAS)
technique and computed ground displacement maps
and time series by inverting 283 interferograms
generated from the ascending and 289 from the
descending orbits to reveal Mt. Etna surface
deformation from 1992 to 2006. Our analysis shows
that the volcano experienced magmatic
inflation/deflation and radial spreading of the west,
south and east flanks. In particular, the summit area
vertical deformation inverted its sign after 2000 and
clearly shows a deflation effect related to the 2001 and
2002 eruptive and seismic events. On the contrary, the
horizontal signals revealed on the eastern and western
flanks present significant and consistent motions
toward east and west, respectively, during the
investigated interval. Overall, the presented results
show the complex and articulated deformation
behavior of Mt. Etna and remark the possible
coexistence of both gravity and magma forcing
The 2004–2006 uplift episode at Campi Flegrei caldera (Italy): Constraints from SBAS-DInSAR ENVISAT data and Bayesian source inference
We investigate the 2004–2006 uplift phase of Campi
Flegrei caldera (Italy) by exploiting the archive of ascending
and descending ENVISAT SAR data acquired from
November 2002 to November 2006. The SBAS-DInSAR
technique is applied to generate displacement mean velocity
maps and time series. An appropriate post-processing step is
subsequently applied to map the areas whose temporal
deformation behavior is correlated with that of the
maximum uplift zone. Our results show that the
deformation also extends outside the volcanological limits
of the Neapolitan Yellow Tuff caldera, without significant
discontinuities. The DInSAR data are inverted by
considering a finite spheroid and an isotropic pointsource.
The inversion results suggest that the new uplift is
characterized by a source location similar to the previous
small uplift event of 2000 and to the long term subsidence
of the 1990’s. In particular, the source is located at a depth
of about 3.2 km and very close to the city of Pozzuoli (about
800 m offshore, to the SW); the associated volume variation
is about 1.1 106 m3/year.PublishedL073081.10. TTC - TelerilevamentoJCR Journalreserve
Developing cardiac and skeletal muscle share fast-skeletal myosin heavy chain and cardiac troponin-I expression
Skeletal muscle derived stem cells (MDSCs) transplanted into injured myocardium can differentiate into fast skeletal muscle specific myosin heavy chain (sk-fMHC) and cardiac specific troponin-I (cTn-I) positive cells sustaining recipient myocardial function. We have recently found that MDSCs differentiate into a cardiomyocyte phenotype within a three-dimensional gel bioreactor. It is generally accepted that terminally differentiated myocardium or skeletal muscle only express cTn-I or sk-fMHC, respectively. Studies have shown the presence of non-cardiac muscle proteins in the developing myocardium or cardiac proteins in pathological skeletal muscle. In the current study, we tested the hypothesis that normal developing myocardium and skeletal muscle transiently share both sk-fMHC and cTn-I proteins. Immunohistochemistry, western blot, and RT-PCR analyses were carried out in embryonic day 13 (ED13) and 20 (ED20), neonatal day 0 (ND0) and 4 (ND4), postnatal day 10 (PND10), and 8 week-old adult female Lewis rat ventricular myocardium and gastrocnemius muscle. Confocal laser microscopy revealed that sk-fMHC was expressed as a typical striated muscle pattern within ED13 ventricular myocardium, and the striated sk-fMHC expression was lost by ND4 and became negative in adult myocardium. cTn-I was not expressed as a typical striated muscle pattern throughout the myocardium until PND10. Western blot and RT-PCR analyses revealed that gene and protein expression patterns of cardiac and skeletal muscle transcription factors and sk-fMHC within ventricular myocardium and skeletal muscle were similar at ED20, and the expression patterns became cardiac or skeletal muscle specific during postnatal development. These findings provide new insight into cardiac muscle development and highlight previously unknown common developmental features of cardiac and skeletal muscle. © 2012 Clause et al
Recommended from our members
Western Diet-Fed, Aortic-Banded Ossabaw Swine: A Preclinical Model of Cardio-Metabolic Heart Failure.
The development of new treatments for heart failure lack animal models that encompass the increasingly heterogeneous disease profile of this patient population. This report provides evidence supporting the hypothesis that Western Diet-fed, aortic-banded Ossabaw swine display an integrated physiological, morphological, and genetic phenotype evocative of cardio-metabolic heart failure. This new preclinical animal model displays a distinctive constellation of findings that are conceivably useful to extending the understanding of how pre-existing cardio-metabolic syndrome can contribute to developing HF
Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS data
We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR)and GPS measurements to determine the source parameters for the three main shocks of the 2016Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw6.1, 5.9, and 6.5,respectively). Our preferred model is consistent with the activation of four main coseismic asperitiesbelonging to the SW dipping normal fault system associated with the Mount Gorzano-Mount Vettore-Mount Bove alignment. Additional slip, equivalent to aMw~ 6.1–6.2 earthquake, on a secondary (1) NEdipping antithetic fault and/or (2) on a WNW dipping low-angle fault in the hanging wall of the mainsystem is required to better reproduce the complex deformation pattern associated with the greatestseismic event (theMw6.5 earthquake). The recognition of ancillary faults involved in the sequencesuggests a complex interaction in the activated crustal volume between the main normal faults and thesecondary structures and a partitioning of strain releas
- …