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Analisi del-l'Affidabilità di Una Platea di Essicazione dei Foraggi di Grandi Dimensioni
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S.TR.E.A.M., system for trace element assessment with mosses. An equation to estimate mercury concentration in freshwaters
No full textHundred experiments of Hg bioaccumulation with the aquatic moss Rhynchostegium riparioides (Hedw.) C.E.O. Jensen transplanted under laboratory conditions were carried out with the aim of (1) measuring the metal uptake at increasing water concentrations (0.25–128 μg Hg2+ L−1) and increasing exposure time (24–189 h), (2) studying the influence of pH (6.3–8.5) and water concentration of Na (3–114 mg L−1), Ca (62–125 mg L−1) and Mg (13–54 mg L−1) on the metal uptake, (3) achieving a database for mathematical and statistical elaborations, and, (4) producing an equation modelling the uptake. A linear uptake was observed for water concentrations 0.05) in the Hg uptake ratio (0.496 × 105 <= Bio Accumulation Factor <= 1.73 × 105). From a database of 28 Hg concentrations in mosses exposed to 0.25–4 μg Hg2+ L−1 for 24–114 h, a mathematical equation was produced, to assess Hg micro-contamination in water. The difference between predicted and real concentration was generally included in the range ± 50%
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
Chemical analyses of spring waters and factor analysis to monitor the functioning of a karstic system. The role of precipitations regimen and anthropic pressures
Full text linkAn approach is presented to study the functioning of a karstic massif and assess the adverse effects of the anthropogenic pressure by monitoring some water chemical and physical parameters of its main springs. The approach has been applied to the Sette Comuni Plateau (Veneto Region, Italy) hosting a well developed karstic system, whose aquifer presents high vulnerability and undergoes a relevant anthropogenic pressure. The Oliero springs, amongst the largest karstic springs in Europe, are the main water output of the plateau. Electrical conductivity, pH, dissolved O2, hardness, alkalinity, chemical oxygen demand, total suspended solids, ionic species (NH4+, NO3−, NO2−, PO43−, SO42−, Cl−, F−), elements (CrIII, CrVI, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg, Pb), and some chlorinated solvents were monitored for one year. This study presents the application of a factor analysis on the water parameters enabling the identification of the dominant chemical and biological processes and pollution sources affecting the karstic system. Results show four factors which are interpreted as karstification, photosynthesis, storm flow pollution and anions. Finally, by associating metals, chemical oxygen demand and total suspended solids with the amount of rainfall in the 48 h before samplings, further detailed information to the fast response of the aquifer to precipitation events was detected and interpreted according to the factor analysis results. The proposed approach, by providing information on the functioning of the aquifer, may help the management of the karstic plateau and is easily adaptable to similar environments
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
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