1,720,964 research outputs found
Salt Water Contamination On Venice lagoon Mainland: New Evaluation Of Origin, Extension And Dynamics
No full textThe Venice Lagoon mainland is affected by salt water contamination in coastal and circum-lagoonal aquifers due to the close vicinity of both the sea and lagoon. The territory, characterized lithologically by alternating layers of silt, clay and sand which have marine, continental and/or marsh origins, is characterized by several critical conditions. These include the existence of paleorivers, lagoonal paleochannels, and rivers which are artificially suspended above the surrounding land by dikes. All of these conditions contribute to an increase in groundwater salinization. Areas with high permeability seem to constitute a preferential way of movement for salt water from the sea or lagoon towards the mainland. Old fossil water seems to be able to reach the surface and contribute to an increase in the process of salt pollution. In fact, during the 1970s, several studies had detected, throughout the territory, the existence of a deep salt water aquifer storing fossil saline water. This aquifer lies at a depth of about 300-450 m in the southern part of the study area and of more than 600 m in the northern part of the Venice mainland. Salt water contamination of subsoil could cause ground salinization and, consequently, desertification of the area, with great economical consequences. These include damaging the large agricultural development of the territory as well as having adverse impacts on the tourist industry.
The combined use of adequately validated geophysical and geochemical tools confers a multidisciplinary character to the research and allows for the definition of the phenomenon’s superficial extension. Geophysical analysis based on Vertical Electrical Sounding (VES) and conductivity logs have been performed together with water table measurements and geochemical analysis on samples collected from selected wells. Moreover, a critical review of old geophysical data allowed for the verification of possible saline contamination changes in time.
Interesting results have been obtained within the northern sector of the Venice lagoon mainland, specifically within territory of Jesolo. In this case, considering the influence of the Piave and Sile rivers and the presence of a coastal sand dune, it is possible to create a map of salt water contamination to evaluate the agricultural use of superficial water.
Therefore, the aim of this research is to define the effective origin of salt water found in the aquifers of the northern lagoon mainland, its distribution, extension and its preferential way of movement within the territory. Thereby, relating all the information acquired to the geological, geomorphological and stratigraphic characteristics of the area
Salt water intrusion in aquifers of the south oriental coastal zones of Sicily. IAEA-CN-118/124
No full textKarst and geothermal water circulation in the Central Appennines (Italy)
No full textProceedings of an advisory group meeting on the application of isotope techniques in the study of the hydrology of fractured and fissured rocks organized by the International Atomic Energy Agency
Hydrochemistry and isotopic characteristic of the submarine spring of south-eastern Sicily.
No full textCharacterization of Submarine Groundwater Discharge along the southeastern coast of Sicily (Italy)
No full textIn research and management of groundwaters, an important role is played by coastal aquifers. Pollution due to salinization and human activities poses serious concerns to the economy of the related territories. Under the project, established through collaboration between the Italian Universities of Palermo, Bari, Venice and the IAEA and the UNESCO, study of coastal aquifers from Syracuse to Donnalucata on the southeastern coast of Sicily was carried out. The study area, known as Hyblean Plateau, is characterized by carbonate and vulcanite outcrops, connected to the tectonic activity during the Cretaceous and the Pliocene period. The aquifers are subjected to overexploitation due to the high water demand for intensive agricultural practices. Thus, the equilibrium between fresh groundwaters and seawater is getting disturbed with consequent salinization. The research project involved the geochemical and isotopic study of well waters, springs and submarine discharges in order to understand the relationships existing among these waters, to identify the best tracers of the natural and human–related phenomena occurring in the area as well as to estimate the presence of possible environmental effects of them on the coastal ecosystem. Hydrogeochemical surveys were carried out, every three months, from 2002 to 2004 on a net of wells, sub-aerial and submarine springs. The present report synthesizes the main results of the research
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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