1,721,146 research outputs found
La bieticoltura in Italia tra lo sviluppo ipotizzato nelle memorie della Società Agraria di Bologna e il declino odierno. Il ruolo della meccanizzazione nella evoluzione della coltura
No full textDopo una introduzione sulla diffusione della coltura della barbabietola da zucchero in Italia, ipotizzata nelle memorie della Società Agraria di Bologna alla fine del secolo diciannovesimo, sono considerate le tappe fondamentali della bieticoltura nel nostro Paese, gli aspetti tecnici legati all'evoluzione della coltura con particolare riferimento alla diffusione delle macchine per la semina e la raccolta. La trattazione conclude con l'analisi del declino della superficie coltivata in Italia.Amade
Study of sorption of copper on complexing resin columns by solid phase extraction.
No full textThe position of the breakthrough pro®le of a substance sorbed on solid phase columns is given by the central point of the
breakthrough curve, VC. This is the volume of eluted solution for which the concentration of the substance is half of that
present in the original solution. VC depends on the characteristics of the column (volume of the stationary and mobile phase)
and on the distribution ratio KD. In the case of the sorption of metal ions on complexing resins, the distribution ratio can be
evaluated from the exchange coef®cients of the metal ion on the resin, which in turn depend on the conditions considered. In
the present paper the dependence of the exchange coef®cients on the conditions (acidity and composition of the solution,
composition of the resin phase) is accounted for by the Gibbs±Donnan model for the ion-exchange resin. In this work it is
shown that KD calculated on the basis of the model is suf®ciently accurate to allow the prediction of VC. The sorption of
copper(II) on column of complexing resin was studied by determining the breakthrough curves, whose position on the eluted
volume axis was evaluated by the central point VC. Two complexing resins were considered, with different sorbing properties
towards copper(II), Chelex 100 and Amberlite CG50, containing iminodiacetic and carboxylic groups, respectively. It was
found that the values of VC calculated from the model are in acceptable agreement with those obtained experimentally under
different conditions. The presence in solution phase of substances able to complex copper(II) was also examined. They have an
in ̄uence on KD and VC as expected on the basis of the model, considering the values of the side reaction coefficients
Tradizione protestante e ricerca storica. L'impegno intellettuale di Giorgio Spini. Giornata di studio Torino 8 novembre 1996
No full text
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
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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