1,721,008 research outputs found
New geophysical knowledge of groundwater systems in Venice estuarine environment
No full textUnconfined aquifers beneath the south sector of the Venice Lagoon are characterized by the presence of saline water. The results of this study allow the determination of the superficial extension of the salt water contamination in the direction of the mainland and the relationship between chemical analysis and conductivity, which reveals a complex lateral and vertical variability in both the permeability and textural pattern. Moreover, geophysical data validated by log data together with other physical and chemical results show a dislocation of the aquifer basement. This fact allows for the presumption that the salt groundwater distribution is affected by a regional tectonic lineament which extends towards the SE. Therefore salt contamination may be due to saline intrusion from the sea and the lagoon, and also from fossil brines mobilised by the combined action of tectonics and infiltration of fresh groundwater
Contaminazione salina nei sistemi acquiferi dell'entroterra meridionale della laguna di Venezia
No full textGroundwater flow in mountainous limestone aquifers deduced from hydrochemical and isotopic data (Orobic Alps, Italy)
No full textDetecting the origin of salt water contamination in groundwater in a lagoon area by the combined use of geophysical and geochemical tools: the example of the southern Venice Lagoon mainland
No full textThe south sector of the Venice Lagoon mainland is a territory characterized by the presence of saline contamination.
Sea water contamination is registered in groundwater near the coastline, and tidally dispersed sea water is usually found in the riverbeds, suspended above the surrounding land. Geophysical research, confirmed by some deep drillings, detected throughout the territory the existence of a deep salt-water aquifer storing fossil saline water at a depth of about 450 m. This research aimed to verify whether the deep fossil saline water could contribute to the salt contamination of the lagoonal mainland. Therefore, together with a critical revision of old geophysical data (vertical electric sounding -VES-, acquired during the 1970s), new geophysical sounding and geochemical analysis were performed. The revision of the geophysical data shows the presence of a dislocation of the aquifer basement: a deep buried tectonic lineament seems to affect the salt-groundwater distribution, apart from the lateral and vertical variability of permeability and the textural pattern of the stratigraphic succession. Moreover, the geochemical-isotopic analyses show the presence of fossil water in the unconfined aquifer. Therefore, salt contamination may be due to saline ingression from the sea and the lagoon, and also by the mobilization of fossil brines by means of a combined action of tectonics and fresh water dilution processes. The aim of this study is to understand the real origin of saltwater by means of chemical and isotopic analysis of water samples collected all over the area, determining the groundwater age and chemical composition and therefore, distinguishing old fossil waters from actual marine water
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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