1,720,998 research outputs found
Microreactor-Mediated Organocatalysis: Towards the Development of Sustainable Domino Reactions
No full textMicroreactor-mediated organocatalysed Michael reactions have been developed. By using a soluble proline-derived catalyst, Michael-type reactions, leading to γ-nitroketones, have been optimized in homogeneous and continuous-flow conditions. As proof of principle, an integrated microfluidic system able to perform domino processes useful in the preparation of bicyclo[4.4.0]decanes with six contiguous stereogenic centres has been set up
Regio- and stereochemistry of Na-mediated reductive cleavage of alkyl aryl ethers
No full textWe have investigated the regio- and stereochemistry of the reductive dealkoxylation of alkyl aryl ethers.
Chiral non-racemic secondary alcohols were converted into the corresponding m-terphenyl or 2-biphenyl
ethers either via inversion of configuration under Mitsunobu reaction conditions or with retention of
configuration under SNAr conditions. The successive cleavage of the aromatic CAO bond occurred in
the presence of a stoichiometric amount of Na metal in dry tetrahydrofuran at rt with retention of
configuration, thus highlighting that the overall inversion or retention of configuration for the whole
two-step procedure is dictated by the stereochemistry of the first synthetic ste
Special Issue: Novel Approaches for the Analytical Evaluation of Food Quality and Authenticity
No full textVerifying the quality and authenticity of agri-food products is essential to guaranteeing adequate food safety for consumers [...
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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