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Palladium-catalyzed electrochemical carbonylation of alkynes, under very mild conditions
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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
An electron spin resonance and voltammetric investigation of some 2-mono- and 2,4-disubstituted pyridinyl radicals
No full textThe chemical reduction of some 2-monosubstituted and 2,4-disubstituted pyridinium ions has been investigated by means of e.s.r. spectroscopy and the results compared with those of an electrochemical study on the same species. By combining the electrochemical and e.s.r. data, a scale of stability has been determined for the investigated pyridinyl radicals. N-Methyl-2-cyanopyridinyl, which was found to be too unstable to be observed, eventually evolved to the 2,4-dicyano-substituted radical. E.s.r. studies have also been carried out on the structurally similar, although more persistent, N-germylpyridinyls
Electrochemical behaviour of PdII(PPh3)2Cl2 in the presence of carbon monoxide and its use in the palladium-catalyzed electrochemical formylation of iodoanisole
No full text“Pd °(PPh3)2” generated by electroreduction of PdII(PPh3)2Cl2 in the presence of carbon monoxide exists mainly in the form of low-ligated zerovalent palladium complex Pd °(PPh3)2CO. On the basis of the experimental results, a mechanism is proposed for its formation. The oxidative addition of 4-iodoanisole to zerovalent palladium centre to afford a cyclic palladium(II) centre seems to be very efficient, but the 4-anisaldehyde formation undergoes severe competition with the two-electron reduction yielding anisole
Formation reversible d'un hydrure de palladium (II) cationique HPd(PPh3) 2+ par addition oxydante de l'acide acetique ou formique avec le palladium(0)
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
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