210 research outputs found

    Study of the geomorphological and archaeological aspects of Sintra area (Portugal) as contribution to its tourist appraisal and promotion

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    The Portughese town of Sintra is an UNESCO world heritage site for itscultural and environmental aspects. The town is located 30 km from Lisbon and 15km from the Atlantic Ocean, and is a touristic site in every seasons mainly for itsarchitectural qualities. This work describes the geomorphological and archaeologicalaspects of the town and the surrounding Serra de Sintra in order to give an addedvalue to tourist appraisal and promotion of the area. Serra de Sintra is an ellipticigneous massif 10 km E-W and 5 km N-S, 300-500 m above sea level. The geologicalstructure is complex but it can be simplified as a core of sienites surrounded bygranites intruded in a limestone plateau. The morphogenetic processes, besidecommon landforms such as narrow valleys, scarps and ridges, shaped a variety ofparticular granite morphologies such as round block fields, inselbergs, castle koppies,etc…. The most spectacular ones have been described and classified as geosites in adata-base. The oldest archaeological remains dates to the Mesolithic, but the area hasbeen extensively occupied during the Neolitic/Calcolithic, Bronze and Iron Ages. Inhistorical times Romans, Visigots and Arabs left some interesting architectural andlinguistic marks. All the archaeological sites have been classified according tobibliographic, museal data and field surveys. They are also all included in a data-base.GeoArchaeo-Tourist maps at 1:25,000 and 1.10,000 scales of the Serra de Sintra andSintra town are the information results collected in the geomorphological andcultural data-bases. The maps have been implemented, by means of an ArcGIScomputer programme, integrating geological, geomorphological, archaeological andhistorical aspects with the tourist infrastructures (information points, parking areas,accommodations, panoramic points, etc.) in order to obtain documents readable, simple, clear but scientifically accurate also for non-expert users. This study could besuitably simplified and summarized in a guide book, with enclosed GeoArchaeo-Tourist maps, as a contribution to improve the knowledge and appraisal of the Sintraterritory also for its landscape and archaeological aspects

    Impact of nitrogen fertilization and soil tillage on arbuscular mycorrhizal fungal communities in a Mediterranean agroecosystem

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    The impact of nitrogen (N) fertilization and tillage on arbuscular mycorrhizal fungi (AMF) was studied in a Mediterranean arable system by combining molecular, biochemical and morphological analyses of field soil and of soil and roots from trap plants grown in microcosm. Canonical correspondence analysis (CCA) of PCR–DGGE banding patterns evidenced that AMF communities in the field are affected by N-fertilization and tillage. N-fertilization was also the main factor shaping AMF communities in Medicago sativa trap plant soil and roots. The overall sporulation pattern of the different AMF species showed a predominant effect of tillage on AMF communities, as shown by CCA analysis. Funneliformis mosseae was the predominant species sporulating in tilled soils, while Glomus viscosum and Glomus intraradices prevailed in no-tilled soils. Field glomalin-related soil protein content was reduced by tillage practices. Our multimodal approach, providing data on two main production factors affecting soil AMF communities, may help implementing effective agricultural management strategies able to support the beneficial relationship between crops and native AMF symbionts

    The survey and mapping of sand-boil landforms related to the Emilia 2012 earthquakes: preliminary results.

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    Sand boils, which are also known as sand blows or sand volcanoes, are among the most common superficial effects induced by high-magnitude earthquakes. These generally occur in or close to alluvial plains when a strong earthquake (M >5) strikes on a lens of saturated and unconsolidated sand deposits that are constrained between silt-clay layers, where the sediments are converted into a fluid suspension. The liquefaction phenomena requires the presence of saturated and uncompacted sand, and a groundwater table near the ground surface. This geological\u2013geomorphological setting is common and widespread for the Po Plain (Italy). The Po Plain (ca. 46,000 km2) represents 15% of the Italian territory. It hosts a population of about 20 million people (mean density of 450 people/km2) and many infrastructures. Thus, the Po Plain is an area of high vulnerability when considering the liquefaction potential in the case of a strong earthquake. Despite the potential, such phenomena are rarely observed in northern Italy, because strong earthquakes are not frequent in this region; e.g., historical data report soil liquefaction near Ferrara in 1570 (M 5.3) and in Argenta 1624 (M 5.5). In the Emilia quakes of May 20 and 29, 2012, the most widespread coseismic effects were soil liquefaction and ground cracks, which occurred over wide areas in the Provinces of Modena, Ferrara, Bologna, Reggio Emilia and Mantov

    The survey and mapping of sand-boil landformsrelated to the Emilia 2012 earthquakes: preliminary results

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    In this report, we present preliminary results using methods to map the detailed micro-morphology of some representative liquefaction features that normally disappear for the aforementioned reasons, or that are recorded only in qualitative terms. Field surveys and activities were conducted a few days after the May 20 and 29, 2012, mainshocks (M 5.9, M 5.8, respectively). The surveys were carried out using global position system (GPS) and reflex digital cameras. GPS acquisition (tracklog) was used to record the topographic positions of the features and to automatically geolocate/geotag the numerous digital photos acquired. The field data, geomorphological features, and sand-boil location were loaded into a geodatabase and mapped using geographic information systems (GIS). Photogrammetric surveys were carried out on several sand boils using digital reflex cameras with calibrated 20-mm fixed lenses. To build high resolution digital elevation models (DEMs), images were taken from multiple angles to cover the entire areas of the features of interest

    The survey and mapping of sand-boil landforms related to the Emilia 2012 earthquakes: preliminary results.

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    Sand boils, which are also known as sand blows or sand volcanoes, are among the most common superficial effects induced by high-magnitude earthquakes. These generally occur in or close to alluvial plains when a strong earthquake (M >5) strikes on a lens of saturated and unconsolidated sand deposits that are constrained between silt-clay layers, where the sediments are converted into a fluid suspension. The liquefaction phenomena requires the presence of saturated and uncompacted sand, and a groundwater table near the ground surface. This geological–geomorphological setting is common and widespread for the Po Plain (Italy). The Po Plain (ca. 46,000 km2) represents 15% of the Italian territory. It hosts a population of about 20 million people (mean density of 450 people/km2) and many infrastructures. Thus, the Po Plain is an area of high vulnerability when considering the liquefaction potential in the case of a strong earthquake. Despite the potential, such phenomena are rarely observed in northern Italy, because strong earthquakes are not frequent in this region; e.g., historical data report soil liquefaction near Ferrara in 1570 (M 5.3) and in Argenta 1624 (M 5.5). In the Emilia quakes of May 20 and 29, 2012, the most widespread coseismic effects were soil liquefaction and ground cracks, which occurred over wide areas in the Provinces of Modena, Ferrara, Bologna, Reggio Emilia and Mantov

    VLBI Observations of a Complete Sample of Radio Galaxies. VI. The Two FR-I Radio Galaxies B2 0836+29 and 3C465

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    We present 5 GHz global VLBI observations of the two Fanaroff Riley Type I radio galaxies B2 0836+29 and 3C465 (2335+26). For 3C465 we present also 1.7 GHz and 8.4 GHz global VLBI data. In addition VLA observations were used to obtain arsecond resolution continuum and polarization maps at 5 GHz. Both sources are very asymmetric on the parsec-scale, with a core and a one-sided jet, aligned with the main arcsecond scale jet. We place a limit on the milliarcsecond jet to counterjet brightness ratio Bjet_{jet}/Bcjet_{cjet} \gtsim 20 and \gtsim 30 for B2 0836+29 and 3C465 respectively. For 3C465 the strong asymmetry holds to the kiloparsec scale. The brightness asymmetry and the ratio between the core radio power and total radio power allow us to constrain the jet velocity close to the core and the orientation of the radio structure with respect to the line of sight. The results suggest that the plasma speed is relativistic on the parsec scale for both sources, i.e. vjet_{jet} \gtsim 0.75c for B2 0836+29 and vjet_{jet} \gtsim 0.6c for 3C465. While vjet_{jet} decreases from the parsec to the kiloparsec scale in B2 0836+29, in 3C465 the very high vjet_{jet} holds all the way to the kiloparsec-scale {\t bright spot}. Our results are in agreement with the unification scheme suggestion that FR-I radio galaxies are the unbeamed poulation of BL-Lac objects. Furthermore, they reinforce the idea that the central engine in FR-I and FR-II radio galaxies must be qualitatively similar. The different radio morphology could then be due either to an intrinsically different nuclear power, which affects the torus geometry or to different conditions in the region beyond the parsec scale, where a significant deceleration in the FR-I jets occurs.Comment: 28 pages, 4 tables, 8 figures all available under request from [email protected]

    Tests of silicon sensors for the CMS pixel detector

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    The tracking system of the CMS experiment, currently under construction at the Large Hadron Collider (LHC) at CERN (Geneva, Switzerland), will include a silicon pixel detector providing three spacial measurements in its final configuration for tracks produced in high energy pp collisions. In this paper we present the results of test beam measurements performed at CERN on irradiated silicon pixel sensors. Lorentz angle and charge collection efficiency were measured for two sensor designs and at various bias voltages.Comment: Talk presented at 6th International Conference on Large Scale Applications and Radiation Hardness of Semiconductor Detectors, September 29-October 1, 2003, Firenze, Italy. Proceedings will be published in Nuclear Instr. & Methods in Phys. Research, Section

    The survey and mapping of sand-boil landforms related to the Emilia 2012 earthquakes: preliminary results

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    Sand boils, which are also known as sand blows or sand volcanoes, are among the most common superficial effects induced by high-magnitude earthquakes. These generally occur in or close to alluvial plains when a strong earthquake (M >5) strikes on a lens of saturated and unconsolidated sand deposits that are constrained between silt-clay layers [Ambraseys 1988, Carter and Seed 1988, Galli 2000, Tuttle 2001, Obermeier et al. 2005], where the sediments are converted into a fluid suspension. The liquefaction phenomena requires the presence of saturated and uncompacted sand, and a groundwater table near the ground surface. This geological– geomorphological setting is common and widespread for the Po Plain (Italy) [Castiglioni et al. 1997]. The Po Plain (ca. 46,000 km2) represents 15% of the Italian territory. It hosts a population of about 20 million people (mean density of 450 people/km2) and many infrastructures. Thus, the Po Plain is an area of high vulnerability when considering the liquefaction potential in the case of a strong earthquake. Despite the potential, such phenomena are rarely observed in northern Italy [Cavallin et al. 1977, Galli 2000], because strong earthquakes are not frequent in this region; e.g., historical data report soil liquefaction near Ferrara in 1570 (M 5.3) and in Argenta 1624 (M 5.5) [Prestininzi and Romeo 2000, Galli 2000]. In the Emilia quakes of May 20 and 29, 2012, the most widespread coseismic effects were soil liquefaction and ground cracks, which occurred over wide areas in the Provinces of Modena, Ferrara, Bologna, Reggio Emilia and Mantova (Figure 1). These were the causes of considerable damage to buildings and the infrastructure. The soil liquefaction and ground cracks were accompanied by sand boils, which are described in this report. The spatial distribution and geomorphological setting of sand boils and ground cracks are also described here. A detailed three-dimensional (3D) reconstruction of these features is also presented, which was carried out using terrestrial photogrammetry. Since archeological times, fluvial ridges, and in general sandy deposits on low plains have been the preferred sites for human infrastructure, colonial houses, roads, etc. Therefore, it is very important to understand how the local topography/ morphology interacts in the liquefaction processes. Numerous distinctive seismic landforms were generated by the May 2012 strong earthquakes (seven with M >5), and in particular, sand boils and ground fractures. The sand-boil landforms, also known as sand craters or sand volcanoes, are formed by low mounds of sand that have been extruded from fractures [Tuttle 2001]. The cone is a generally shortlived structure that naturally collapses, starting from the center holes that mark the water retreat back into the fracture. Sand boils also occurred along larger cracks (with decimetric lateral and vertical displacements). Here, the upper scarps block the formation of craters and allow the deposition of a sandy layer several centimeters thick (e.g. ca. 4 cm in the San Carlo crack), on the lower side of the steep slope. These landforms are highly vulnerable to erosion. After a few weeks, they are washed out by rain, destroyed by human activity, or masked by growing crops. Thus, ground surveys that investigate these events have to be carried out as soon as possible [Panizza et al. 1981]. In this report, we present preliminary results using methods to map the detailed micro-morphology of some representative liquefaction features (Figure 2) that normally disappear for the aforementioned reasons, or that are recorded only in qualitative terms

    Ground effects induced by the 2012 seismic sequence in Emilia: implications for seismic hazard assessment in the Po Plain

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    Since May 16, 2012, a seismic sequence has affected a wide portion of the Emilia Region (northern Italy), chiefly for the Modena and Ferrara Provinces. The first mainshock (Ml 5.9; focal depth, ca. 6 km) occurred on May 20, 2012, with the epicenter located a few kilometers north of Finale Emilia. A second main shock (Ml 5.8; focal depth, ca. 10 km) occurred on May 29, 2012, about 12 km west of the first earthquake, with the epicenter near Medolla. The seismic sequence has been characterized by five other Ml 655 events, and more than 2,300 aftershocks of lower magnitude, until the end July 2012. The distribution of the aftershocks identifies a WNW-ESE-trending zone ca. 40 km long that is characterized by NNE-SSW nearly pure compression, as indicated by the focal mechanisms. This report focuses on the many ground effects that were induced by this seismic sequence, as mainly cracks, liquefaction-type phenomena, and hydrological anomalies. The aim is to provide a complete representation of such effects, to: illustrate their type, size and areal distribution; identify the zones in the affected area that were most prone to the occurrence of ground effects (i.e., more susceptible to local geological instability in the case of earthquake occurrence); carry out an independent assessment of the intensities of the earthquakes through the ESI 2007 intensity scale, which is based only on coseismic effects on the natural environment

    Deep Learning for AGILE Anticoincidence System's Background Prediction from Orbital and Attitude Parameters

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    AGILE is an Italian Space Agency (ASI) space mission launched in 2007 to study X-ray and gamma-ray phenomena in the energy range from ∼\sim20 keV to ∼\sim10 GeV. The AGILE AntiCoincidence System (ACS) detects hard-X photons in the 50 - 200 keV energy range and continuously stores each panel's count rates in the telemetry. We developed a new Deep Learning (DL) model to predict the background of the AGILE ACS top panel using the satellite's orbital and attitude parameters. This model aims to learn how the orbital and spinning modulations of the satellite impact the background level of the ACS top panel. The DL model executes a regression problem, and is trained with a supervised learning technique on a dataset larger than twenty million orbital parameters' configurations. Using a test dataset, we evaluated the trained model by comparison of the predicted count rates with the real ones. The results show that the model can reconstruct the background count rates of the ACS top panel with an accuracy of 96.7\%, considering the orbital modulation and spinning of the satellite. Starting from these promising results, we are developing an anomaly detection method to detect Gamma-ray Bursts when the differences between predicted and real count rates exceed a predefined threshold.Comment: 4 pages, 2 figure, proceedings of the ADASS XXXIII (2023) conference, to appear in ASP Conference Seri
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