1,721,257 research outputs found
Changes in income inequality and suicide rates after "shock therapy": Evidence from Eastern Europe
No full textMineralizaciones fosfatico-bariticas (+solfuros) en litofacies carbonaticas condensadas devonicas del Sarrabus (SE de la Isla de Cerdena, Italia)
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Synthesis of zeolite Na-A from Halloysite 10 A° and new crystallization kinetic model for the transformation of Na-A into HS zeolite.
No full textThe present work deals with the synthesis of Na-A zeolite using 10 Å halloysite (collected near Grosseto, Italy) as the starting material, instead of the more expensive chemicals currently used in industry (Na aluminates and Na silicates). The process of synthesizing Na-A zeolite from 10 Å halloysite is rather simple as the reaction of halloysite with alkali occurs very readily and is achieved without prior thermal activation at high temperature. The optimal conditions of crystallization of Na-A zeolite from 10 Å halloysite are reached at 80°C. At lower temperatures, transformation of halloysite into an amorphous material requires more time, and the field within which Na-A zeolite exists overlaps that of 7 Å halloysite, G and HS zeolites. The products of synthesis at 80°C were characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma optical emission spectrometry and infrared spectroscopy. We also propose a model to study the reaction kinetics of zeolite (Na-A and HS) nucleation and growth by real-time X-ray powder diffraction data. Copyright © 2005, The Clay Minerals Society
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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