668 research outputs found
Plio-quaternary geology of L’Aquila-Scoppito basin (Central Italy)
We present a geological map at 1: 25,000 scale of the Plio-Quaternary L'Aquila-Scoppito intermontane basin (central Italy), which corresponds to the epicentral area of the 6th April 2009 L'Aquila earthquake (Mw: 6.29). The map is derived from geological field surveys at 1: 5000 scale and takes into account previously published maps. It is supported by a fine-scale LiDAR digital elevation model, paleontological analyses, C-14 dating, well log analyses of deep boreholes, and geophysical data interpretation. By taking into account that the remarkable historical and present-day seismicity of the area is the result of its PlioQuaternary geological evolution, the aim of this study is to produce a fine-scale geological map of the study area through a comprehensive analysis of the occurring Plio-Quaternary synthems and the tectonic processes that are taking place within it
Characterization of the breccia deposits in downtown L’Aquila (Central Italy) through multichannel analysis of surface waves
On April 6th 2009 an Mw 6.3 earthquake hit the historical city of L’Aquila (Central Italy) causing about 300
causalities, more than 39000 homeless and strong damage in the city and in the surrounding villages. L’Aquila
downtown suffered Mercalli-Cancani-Sieberg (MCS; Sieberg 1930) intensity > VIII. Heavy damage and collapses
were concentrated in the unreinforced masonry buildings including historical churches.
Starting from June 2009, the Italian Civil Defense Department promoted a microzoning study of the epicentral
area, aimed at identifying, at a detailed scale, areas were local seismic amplification could occur due to the
characteristics of surface geology.
L’Aquila is founded on a terrace that slopes down moving in the southwest direction, and raises about 50 meters
above the Aterno river bed. The terrace is formed by alluvial Quaternary breccias consisting of limestone clasts in
a marly matrix. In the northern part of the city the terrace is in contact with outcropping limestone, while moving
toward south, breccias are over imposed to lacustrine sediments formed mainly of silty and sandy layers and minor
gravel beds. As found by boreholes, the thickness of the breccias formation ranges from tenths of meters at north
to just few meters at south. The uppermost weathered part of breccias outcrops at south and is indicated as “limi
rossi”. The presence of breccias and “limi rossi” in the northern and southern part of the city respectively, is well
identified by collected geotechnical data. Shear wave velocity (Vs) are quite high in the northern sector and can
reach values of about 1000 m/s, whereas in the southernmost part the Vs of “limi rossi” drops down to 300-400
m/s. The microzoning studies at L’Aquila evidenced the presence of low-frequency (about 0.6 Hz) amplification
diffused in the historical center with high amplification factors in the southern area of the city were “limi rossi”
outcrops.
We here present the results of multichannel surface waves analysis (MASW) based on active and passive sources.
Active methods consist of 1D linear arrays of 4.5 Hz-vertical geophones using a minigun as source. Passive
methods consist of 2D arrays of seismic three-component sensors. In order to investigate the low-frequency
amplification, the geometry of 2D arrays was accordingly designed, using 16 seismic stations with maximum
aperture of 1 km that recorded many hours of ambient seismic noise. We deployed three 2D arrays, one in the
northern part and two in the southern part of the city. The 1D linear array was dedicated to characterize the
shallower part of “limi rossi”.
With the aim to derive the shear wave velocity profiles, the apparent phase velocity estimated through arrays
technique has been inverted through a neighborhood algorithm
Characterization of the breccia deposits in downtown L’Aquila (Central Italy) through multichannel analysis of surface waves
On April 6th 2009 an Mw 6.3 earthquake hit the historical city of L’Aquila (Central Italy) causing about 300 causalities, more than 39000 homeless and strong damage in the city and in the surrounding villages. L’Aquila downtown suffered Mercalli-Cancani-Sieberg (MCS; Sieberg 1930) intensity > VIII. Heavy damage and collapses
were concentrated in the unreinforced masonry buildings including historical churches.
Starting from June 2009, the Italian Civil Defense Department promoted a microzoning study of the epicentral area, aimed at identifying, at a detailed scale, areas were local seismic amplification could occur due to the characteristics of surface geology.
L’Aquila is founded on a terrace that slopes down moving in the southwest direction, and raises about 50 meters above the Aterno river bed. The terrace is formed by alluvial Quaternary breccias consisting of limestone clasts in a marly matrix. In the northern part of the city the terrace is in contact with outcropping limestone, while moving
toward south, breccias are over imposed to lacustrine sediments formed mainly of silty and sandy layers and minor gravel beds. As found by boreholes, the thickness of the breccias formation ranges from tenths of meters at north to just few meters at south. The uppermost weathered part of breccias outcrops at south and is indicated as “limi
rossi”. The presence of breccias and “limi rossi” in the northern and southern part of the city respectively, is well identified by collected geotechnical data. Shear wave velocity (Vs) are quite high in the northern sector and can reach values of about 1000 m/s, whereas in the southernmost part the Vs of “limi rossi” drops down to 300-400
m/s. The microzoning studies at L’Aquila evidenced the presence of low-frequency (about 0.6 Hz) amplification diffused in the historical center with high amplification factors in the southern area of the city were “limi rossi” outcrops.
We here present the results of multichannel surface waves analysis (MASW) based on active and passive sources.
Active methods consist of 1D linear arrays of 4.5 Hz-vertical geophones using a minigun as source. Passive methods consist of 2D arrays of seismic three-component sensors. In order to investigate the low-frequency
amplification, the geometry of 2D arrays was accordingly designed, using 16 seismic stations with maximum aperture of 1 km that recorded many hours of ambient seismic noise. We deployed three 2D arrays, one in the northern part and two in the southern part of the city. The 1D linear array was dedicated to characterize the shallower part of “limi rossi”.
With the aim to derive the shear wave velocity profiles, the apparent phase velocity estimated through arrays
technique has been inverted through a neighborhood algorithm
Surface faulting and liquefaction hazard assessment in the central Apennines for land use practices: a case study from the L’Aquila urban area (central Italy)
Measurement and simulation of reflector antenna
Well-established procedures are consolidated to determine the associated measurement uncertainty for a given antenna and measurements scenario [1-2]. Similar criteria for establishing uncertainties in numerical modelling of the same antenna are still to be established. In this paper, we investigate the achievable agreement between antenna measurement and simulation when external error sources are minimized. The test object, is a reflector fed by a wideband dual ridge horn (SR40-A and SH4000). The highly stable reference antenna has been selected to minimize uncertainty related to finite manufacturing and material parameter accuracy. Two frequencies, 10.7GHz and 18GHz have been selected for detailed investigation
Diagnostic challenges of an incidental finding: case report of definitely-congenital glioblastoma multiforme in a very preterm infant
Background: Congenital brain tumors are extremely rare in the neonatal population, and often associated with a poor prognosis. The diagnostic suspicion is often aroused at antenatal scans or postnatally, if clinical signs and symptoms of increased intracranial pressure become evident. We present a case of definitely congenital glioblastoma multiforme incidentally diagnosed in a preterm infant, aiming to raise clinical awareness on this condition and to highlight the challenges of the related diagnostic work-up. Case presentation: This female infant was born at 31 weeks’ gestation after an uneventful pregnancy. No abnormalities were detected at antenatal ultrasound scans and genetic tests. Head circumference at birth was on the 25th centile. A routine brain ultrasound scan performed on day 1 revealed a large, inhomogeneous lesion in the right cerebral hemisphere, with contralateral midline shift, which was confirmed by brain magnetic resonance imaging (MRI). Eye fundus and routine blood exams, including platelets count, coagulation screening and C-reactive protein, were normal. Given the high risk of complications, surgical biopsy of the lesion was temporarily hold and a daily sonographic follow-up was undertaken. Although head circumference growth was steady on the 25th centile, progressive changes of the lesion were detected by cranial ultrasound. The repeat MRI scans showed a significant enlargement of the mass, with contralateral midline shift and signs of intralesional and intraventricular bleeding. In view of this worsening, surgical resection was performed. The histological examination of the lesion biopsy documented a GFAP+ highly cellular neoplasm, with no mutation on SMARCB1 gene. At the molecular analysis, mutations on IDH and H3F3A genes were absent, whereas MGMT promoter was unmethylated. The diagnosis was grade IV glioblastoma IDH wild-type. Conclusions: Congenital glioblastoma multiforme is an extremely rare but highly aggressive neoplasm. Since intralesional biopsy is not often feasible in affected neonates, knowledge of the associated clinical and neuroradiological features is particularly important, as they can also add useful information on the neoplasm behavior. Specimens from open surgical resection allow to perform a definite histological analysis and an extended molecular characterization, with relevant prognostic implications
Role of microRNAs in the main molecular pathways of hepatocellular carcinoma
Hepatocellular carcinoma (HCC) is the most common primary liver malignant neoplasia. HCC is characterized by a poor prognosis. The need to find new molecular markers for its diagnosis and prognosis has led to a progressive increase in the number of scientific studies on this topic. MicroRNAs (miRNAs) are small noncoding RNA that play a role in almost all main cellular pathways. miRNAs are involved in the regulation of expression of the major tumor-related genes in carcinogenesis, acting as oncogenes or tumor suppressor genes. The aim of this review was to identify papers published in 2017 investigating the role of miRNAs in HCC tumorigenesis. miRNAs were classified according to their role in the main molecular pathways involved in HCC tumorigenesis: (1) mTOR; (2) Wnt; (3) JAK/STAT; (4) apoptosis; and (5) MAPK. The role of miRNAs in prognosis/response prediction was taken into consideration. Bearing in mind that the analysis of miRNAs in serum and other body fluids would be crucial for clinical management, the role of circulating miRNAs in HCC patients was also investigated. The most represented miRNA-regulated pathway in HCC is mTOR, but apoptosis, Wnt, JAK/STAT or MAPK pathways are also influenced by miRNA expression levels. These miRNAs could thus be used in clinical practice as diagnostic, prognostic or therapeutic targets for HCC treatment
- …