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La presenza naturale di amianto nelle rocce e nei suoli ofiolitici: il censimento dei siti a rischio amianto durante la realizzazione della cartografia geologica della Regione Liguria
No full textBackground levels of potentially toxic elements in ultramafic soils from the Voltri Unit: a mineralogical and geochemical approach
No full textUltramafic soils are characterized by the presence of several potentially toxic elements (PTE's; such as Cr, Co, and Ni) that commonly exceed residential and industrial concentration limits according to Italian laws (D.M. 471/1999; D.Lgs 152/2006). Therefore, the determination of the background levels and baseline values of PTE's within serpentinitic and peridotitic soils is of paramount importance in order to evaluate the potential risk of contamination for ecosystems as well as to distinguish between lithogenic and anthropogenic inputs. With this work we investigated the mineralogy, the mineral chemistry, and the bulk chemistry of undisturbed soils and associated parent rocks from four selected sites occurring in the "Bric del Dente Serpentinite" and "Monte Tobbio Peridotite" Formations (Voltri Unit, Ligurian Alps). Selected metal and semimetal concentrations (V, Cr, Co, Ni, Cu, Zn, As, Cd, Sb, Pb) were assessed by ICP-OES at the ARPA-Liguria laboratories according to the EPA-3050B and EPA-6010 methods. The mineralogy and the mineral chemistry of soils and rocks have been determined by means of optical microscopy (transmitted- and
reflected light) and electron microprobe analyses (WDS). The bulk chemistry analyses evidenced very high concentrations of Cr (up to 3020 ppm in rocks and 1269 ppm in soils), Ni (up to 1855 ppm in rocks and 1041 ppm in soils), Co (up to 85 ppm in rocks and 64 ppm in soils), and V (up to 199 ppm in rocks and 39 ppm in soils). The
mineralogical results showed that most of the Cr is contained within primary Fe-oxides and spinels (mainly magnetite and chromite). Olivine and serpentine group minerals are the main Ni-bearing minerals though non-trascurable Ni concentration have been also detected in Fe-oxides and Ni-sulphides. Among the other identified primary minerals only chlorites are characterized by significant, though very variable, amounts of Co, V, Ni. In general, most of the detected metal-bearing mineral species resulted completely unaltered either in rocks and soils evidencing their resistance to weathering and their tendency to remain as stable residual minerals within soils. Secondary authigenic minerals in soils are mainly represented by Fe-oxides and -oxyhydroxides and clay minerals. In general they contain relative small amounts of PTE's if compared to primary minerals and cannot be considered as the main source for the bulk metal content of soils. These preliminary results evidenced that all the studied rocks and soils have a baseline values of Cr, Ni, Co, and V well above (up to one order of magnitude) concentration limits of the Italian laws for industrial and
residential sites. These baseline values should be considered as the natural background levels of the studied soils since most of the metals are related to the residual mineral species derived from the parent rocks. Further studies are in progress, through leaching experiments, to determine the relative mobility and bioavailability of the studied metals
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
Logistic regression analysis for assessing indoor radon concentrations in geologically complex realms
No full textLa presenza naturale di amianto nelle rocce e nei suoli ofiolitici: il censimento dei siti a rischio amianto durante la realizzazione della cartografia geologica della Regione Liguria
No full textVariations 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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