1,723,030 research outputs found
Geochimica isotopica
No full textNegli ultimi decenni, gli isotopi stabili dell’ossigeno e dell’idrogeno sono comunemente utilizzati per stabilire l’origine delle acque e le aree di alimentazione degli acquiferi; mentre, il trizio e gli isotopi del carbonio sono utilizzati per la valutazione dei tempi di residenza delle acque nei serbatoi.
La caratterizzazione isotopica delle risorse idriche sotterranee, che si sviluppano nel territorio ferrarese, con particolare interesse al primo (A1-I) e secondo acquifero in pressione (A2-I), è stata realizzata, tramite l’elaborazione, di dati provenienti da una rete di monitoraggio costituita da 18 pozzi (database ARPA, progetto SINA; RAPTI CAPUTO, 2000). In particolare, sono stati utilizzati dieci campioni d’acqua per la caratterizzazione isotopica del sistema acquifero A1-I ed otto per quello A2-I. Nei campioni raccolti sono stati analizzati i rapporti isotopici 18O/16O, D/H ed il contenuto il tritio (T), carbonio-14 (14C) e carbonio-13 (13C).
Tenendo in considerazione tutti i campioni, l’analisi dei dati isotopici ci ha permesso di osservare valori del rapporto 18O/16O compresi tra -10,86 e -7,44, mentre, il rapporto isotopico D/H mostra valori compresi tra -72,79 e -48,99.
La distribuzione dei valori isotopici relativi all’ossigeno e all’idrogeno (fig. 32) riflette, in generale, la presenza di acque di molteplice origine, da padano-alpina, ad appenninica e fino ad acque 'locali'
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
First lattice calculation of the electromagnetic operator amplitude (Pi0|Q(+)gamma|K0)
No full textWe present the first lattice calculation of the matrix element of the electromagnetic operator [pi (0)|Q(+)(gamma)|K(0)], where = Q(+)(gamma) = (Q(d)e/16 pi (2))((s) over bar (L)sigma (mu nu) F(mu nu)d(R) + (s) over bar (R)sigma (mu nu) F(mu nu)d(L)) This matrix element plays an important roe, since it contributes to enhance the CP violating part of the K-L --> pi (0)e(+)e(-) amplitude in supersymmetric extensions of the Standard Model
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
‘‘Pieve Santo Stefano’’ is not a mud volcano: Comment on ‘‘Structural controls on a carbon dioxide-driven mud volcano field in the Northern Apennines’’ (by Bonini, 2009)
No full textBonini (2009) has recently written an interesting paper dealing with the structural setting and relationships to seismicity of a CO2(carbon dioxide)-driven mud volcano, called Pieve S. Stefano (PSS),
located in the Northern Apennines of Italy.We outline here that PSS is not a mud volcano at all. The author erroneously attributes the term ‘‘mud volcano’’ (also featured in the title of the article) to
a CO2-dominant gas manifestation, which should be considered as a ‘‘mofette’’ or more generally a dry CO2-vent (or ‘‘gas pool’’; Minissale et al., 2000; Heinicke et al., 2006). Our comment does not dispute Bonini’s data interpretations and conclusions (for which a first comment has already been made by Collettini, in press), but discusses why misuse of the term ‘‘mud volcano’’ may lead to misquotations in future mud volcano literature.Published1270-12714.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalreserve
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