1,721,019 research outputs found
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
NHC-Stabilized Iridium Nanoparticles as Novel Catalysts in Hydrogen Isotope Exchange Reactions of Anilines
No full textThe preparation of N‐heterocyclic carbene‐stabilized iridium nanoparticles and their application in hydrogen isotope exchange reactions is reported. These air‐stable and easy‐to‐handle iridium nanoparticles showed a unique catalytic activity, allowing selective and efficient hydrogen isotope incorporation on anilines using D2 or T2 as isotopic source. The usefulness of this transformation has been demonstrated by the deuterium and tritium labeling of diverse complex pharmaceuticals
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
Directed Iridium-Catalyzed Hydrogen Isotope Exchange Reactions of Phenylacetic Amides and Esters
No full textFor the first time, we describe a catalytic protocol for highly selective hydrogen isotope exchange (HIE) of phenylacetic acid amides and esters under very mild reaction conditions. Using a homogeneous iridium catalyst supported by a bidentate phosphine-imidazolin-imine P,N ligand, the HIE reaction on a series of phenylacetic derivatives proceeds with high yields, high selectivity and with deuterium incorporation up to 99%. The method is fully adaptable to the specific requirements of tritium chemistry, and its effectiveness was demonstrated by direct tritium labelling of the fungicide benalaxyl and the drug camylofine. Further insights into the mechanism of the HIE reaction with catalyst 1 have been provided utilizing DFT calculation, NMR-studies and X-ray diffraction analysis
Comparison of Iridium(I) catalysts in Temperature mediated Hydrogen Isotope Exchange Reactions
No full textThe reactivity and selectivity of iridium(I) catalysed hydrogen
isotope exchange (HIE) reactions can be varied by using wide
range of reaction temperatures. Herein, we have done a detailed
comparison study with common iridium(I) catalysts (1–6) which
will help us to understand and optimize the approaches of either
high selectivity or maximum deuterium incorporation. We have
demonstrated that the temperature window for these studied
iridium(I) catalysts is surprisingly very broad. This principle was
further proven in some HIE reactions on complex drug
molecules
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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