102,502 research outputs found
Very high resolution seismic surveys in the lagoon and gulf of Venice shallow waters
No full textWithin the framework of the geological mapping of the Venice area (CARG Project: Map Sheet 128 “Venezia” and Map Sheet 148-149 “Chioggia-Malamocco”) a very high resolution seismic survey (VHRS) was carried out to correlate data from hundreds of cores with the main aim to map the depth of the Late Pleistocene and Holocene unconformity (Brancolini et al., 2005; Rizzetto et al., 2005; Tosi et al., 2006a,b). Due to logistic and technical limits, the acquisition of seismic survey in the Venice Lagoon was restricted to the channels with more of 5 m water depth, most of them artificial or dredged. A new survey, with the aim to extend the VHRS surveys to the shallow water, such as the tidal flats, is in progress within the Co.Ri.La. Project framework (3.16 Subproject). The Co.Ri.La 3.16 Subproject is based on an acquisition system installed on a boat with a very shallow draught. The new survey will allow the detection and mapping of many interesting geological-geomorphologic structures, i.e. paleoriver beds, ancient lagoon channels and shoreline ridges, that are like-outcropping, and that have been only partially recognized in the previous surveys.PublishedBarcelona (Spain)7A. Geofisica di esplorazioneope
Very high resolution seismic surveys in the lagoon and gulf of Venice shallow waters
No full textWithin the framework of the geological mapping of the Venice area (CARG Project: Map Sheet 128 “Venezia” and Map Sheet 148-149 “Chioggia-Malamocco”) a very high resolution seismic survey (VHRS) was carried out to correlate data from hundreds of cores with the main aim to map the depth of the Late Pleistocene and Holocene unconformity (Brancolini et al., 2005; Rizzetto et al., 2005; Tosi et al., 2006a,b). Due to logistic and technical limits, the acquisition of seismic survey in the Venice Lagoon was restricted to the channels with more of 5 m water depth, most of them artificial or dredged. A new survey, with the aim to extend the VHRS surveys to the shallow water, such as the tidal flats, is in progress within the Co.Ri.La. Project framework (3.16 Subproject). The Co.Ri.La 3.16 Subproject is based on an acquisition system installed on a boat with a very shallow draught. The new survey will allow the detection and mapping of many interesting geological-geomorphologic structures, i.e. paleoriver beds, ancient lagoon channels and shoreline ridges, that are like-outcropping, and that have been only partially recognized in the previous surveys.PublishedBarcelona (Spain)7A. Geofisica di esplorazioneope
CONTRIBUTION OF SEISMIC PROFILES, HISTORICAL MAPS, AND DIGITAL ELEVATION MODEL TO DEFINE BURIED GEOMORPHOLOGICAL FEATURES IN THE VENICE LAGOON SUBSOIL (ITALY)
No full textRecently, the integrated analysis of Very High Resolution Seismic (VHRS) profiles, satellite images, aerial photographs, maps, and topographic/bathymetric data has given an important contribution to the identification of buried geomorphological features in the Venice lagoon subsoil down to about 30 m b.s.l.. Investigations allow to attribute these features to the Late Pleistocene and the Holocene and to point out their relation with the evolution of the lagoon basin.
Results of this study are also assuming great importance in relation to coastal environmental problems. Relict sandy geomorphological features, characterized by high permeability, act as preferred pathways for groundwater flow and solute transport, enhancing saltwater intrusion in the watershed (Carbognin & Tosi, 2003; Carbognin et al., 2005; Pousa et al., 2007). Furthermore, salinization process can also trigger land subsidence induced by clayey particles rearrangement (Meade, 1964).
In addition, the different kinds of deposits that characterize geomorphological features are responsible for a differential lowering of the territory (Teatini et al., 2005).
Aerial photograph and satellite image interpretations, analysis of historical and recent maps, field surveys, and topographic/bathymetric investigations were first used to identify the main buried and surface geomorphological features. Afterwards, an important contribution to the present study was given by a single channel VHR seismic system, optimized for surveys in shallow water less than 1 m depth (Brancolini et al., 2006; Brancolini et al., 2007).
Seismic profiles were calibrated and validated using geological information obtained from existing cores.
The detailed reconstruction of the seismic-morpho-stratigraphic units present in the subsoil of the Venice Lagoon is still in progress. It is obtained integrating results of the investigations previously described with sedimentological, stratigraphic, geotechnical, mineralogical, textural, and paleoenvironmental data, and 14C dating (Serandrei Barbero et al., 2006; Tosi et al., 2007a; Tosi et al., 2007b).
The combined interpretation of results obtained from remote sensing investigations, topographic/bathymetric measurements, VHRS surveys, and analysis of multidisciplinary geological data allowed the discovery and characterization of buried paleoriver beds, ancient tidal channels, and paleobeach ridges and pointed out the relation among geomorphological features occurring in the lagoon basin and in the watershed.
In fact, most of the features recognized in the mainland, which apparently come to an end in correspondence to the lagoon margin, continue into the lagoon basin, where their identification is made difficult by the presence of water and by depositional/erosive processes active in this kind of environment.
Data show that relict geomorphological features composed of high permeability deposits provide the hydraulic connection between freshwater aquifers and the sea. In particular, results of the present study point out that well developed paleoriver systems, intersecting the southern lagoon margin and the nearby coastline and characterized by permeable sediments, represent preferential way of communication among waters having different salinity. By contrast thick silty-clayey layers preclude the salty pollution in the aquifers from the lagoon and the sea.
As pointed out close to the lagoon margin (Rizzetto et al., 2003), the different kinds of deposits, related to the presence of distinct geomorphological features, contribute to the differential lowering of the lagoon basin (Teatini et al., 2005). In particular, organic soils correspond to highly sinking areas, whereas sandy-silty sediments, which constitute fluvial and beach ridges, are more stable.
Future investigations have to be addressed to the quantitative geomorphological analysis aimed to know the past hydrologic conditions of the drainage systems, and to analyze the formative processes that control the morphological setting and evolution of lowland fluvial river and tidal creek systems.PublishedMunich, Germany6A. Monitoraggio ambientale, sicurezza e territorioope
CONTRIBUTION OF SEISMIC PROFILES, HISTORICAL MAPS, AND DIGITAL ELEVATION MODEL TO DEFINE BURIED GEOMORPHOLOGICAL FEATURES IN THE VENICE LAGOON SUBSOIL (ITALY)
No full textRecently, the integrated analysis of Very High Resolution Seismic (VHRS) profiles, satellite images, aerial photographs, maps, and topographic/bathymetric data has given an important contribution to the identification of buried geomorphological features in the Venice lagoon subsoil down to about 30 m b.s.l.. Investigations allow to attribute these features to the Late Pleistocene and the Holocene and to point out their relation with the evolution of the lagoon basin.
Results of this study are also assuming great importance in relation to coastal environmental problems. Relict sandy geomorphological features, characterized by high permeability, act as preferred pathways for groundwater flow and solute transport, enhancing saltwater intrusion in the watershed (Carbognin & Tosi, 2003; Carbognin et al., 2005; Pousa et al., 2007). Furthermore, salinization process can also trigger land subsidence induced by clayey particles rearrangement (Meade, 1964).
In addition, the different kinds of deposits that characterize geomorphological features are responsible for a differential lowering of the territory (Teatini et al., 2005).
Aerial photograph and satellite image interpretations, analysis of historical and recent maps, field surveys, and topographic/bathymetric investigations were first used to identify the main buried and surface geomorphological features. Afterwards, an important contribution to the present study was given by a single channel VHR seismic system, optimized for surveys in shallow water less than 1 m depth (Brancolini et al., 2006; Brancolini et al., 2007).
Seismic profiles were calibrated and validated using geological information obtained from existing cores.
The detailed reconstruction of the seismic-morpho-stratigraphic units present in the subsoil of the Venice Lagoon is still in progress. It is obtained integrating results of the investigations previously described with sedimentological, stratigraphic, geotechnical, mineralogical, textural, and paleoenvironmental data, and 14C dating (Serandrei Barbero et al., 2006; Tosi et al., 2007a; Tosi et al., 2007b).
The combined interpretation of results obtained from remote sensing investigations, topographic/bathymetric measurements, VHRS surveys, and analysis of multidisciplinary geological data allowed the discovery and characterization of buried paleoriver beds, ancient tidal channels, and paleobeach ridges and pointed out the relation among geomorphological features occurring in the lagoon basin and in the watershed.
In fact, most of the features recognized in the mainland, which apparently come to an end in correspondence to the lagoon margin, continue into the lagoon basin, where their identification is made difficult by the presence of water and by depositional/erosive processes active in this kind of environment.
Data show that relict geomorphological features composed of high permeability deposits provide the hydraulic connection between freshwater aquifers and the sea. In particular, results of the present study point out that well developed paleoriver systems, intersecting the southern lagoon margin and the nearby coastline and characterized by permeable sediments, represent preferential way of communication among waters having different salinity. By contrast thick silty-clayey layers preclude the salty pollution in the aquifers from the lagoon and the sea.
As pointed out close to the lagoon margin (Rizzetto et al., 2003), the different kinds of deposits, related to the presence of distinct geomorphological features, contribute to the differential lowering of the lagoon basin (Teatini et al., 2005). In particular, organic soils correspond to highly sinking areas, whereas sandy-silty sediments, which constitute fluvial and beach ridges, are more stable.
Future investigations have to be addressed to the quantitative geomorphological analysis aimed to know the past hydrologic conditions of the drainage systems, and to analyze the formative processes that control the morphological setting and evolution of lowland fluvial river and tidal creek systems.PublishedMunich, Germany6A. Monitoraggio ambientale, sicurezza e territorioope
Strain Dependent Variation of Immune Responses to A. fumigatus: Definition of Pathogenic Species
No full textFor over a century microbiologists and immunologist have categorized microorganisms as pathogenic or non-pathogenic species or genera. This definition, clearly relevant at the strain and species level for most bacteria, where differences in virulence between strains of a particular species are well known, has never been probed at the strain level in fungal species. Here, we tested the immune reactivity and the pathogenic potential of a collection of strains from Aspergillus spp, a fungus that is generally considered pathogenic in immuno-compromised hosts. Our results show a wide strain-dependent variation of the immune response elicited indicating that different isolates possess diverse virulence and infectivity. Thus, the definition of markers of inflammation or pathogenicity cannot be generalized. The profound understanding of the molecular mechanisms subtending the different immune responses will result solely from the comparative study of strains with extremely diverse properties. © 2013 Rizzetto et al
Geometrical Parameterization and MultiObjective Shape Optimization of Convective Periodic Channels
No full textIn this article we describe a general procedure for the geometric parameterization and multiobjective shape optimization of periodic wavy channels, representative of the repeating module of an ample variety of heat exchangers. The two objectives considered are the maximization of heat transfer rate and the minimization of friction factor. Since there is no single optimum to be found, we use a multiobjective genetic algorithm and the so-called Pareto
dominance concept. The optimization of the two-dimensional periodic channel is obtained, by means of an unstructured finite-element solver, for a fluid of Prandtl number Pr = 0.7,
assuming fully developed velocity and temperature fields, and steady laminar conditions.
The geometry of the channel is parameterized either by means of simple linear-piecewise profiles, or by nonuniform rational B-splines, and in the latter case their control points represent the design variables. The results obtained are very encouraging, and the procedure described can be applied, in principle, to even more complex problems
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