1,720,964 research outputs found
Room temperature palladium-catalyzed hydroarylation of ynamides in water
No full textPd-catalyzed hydroarylation reactions of ynamides were studied in pure water in the presence of the water-soluble industrial TPPTS ligand in comparison with the use of PCy3 or P(o-Tol)3. Pd(OAc)2/TPPTS (3,3′,3′′-phosphanetriyltris(benzenesulfonic acid) trisodium salt) system exhibited high activity for the conversion of various aryl- and alkyl-ynamides in the presence of arylboronic acids bearing either electron-donating and electron-withdrawing groups. The hydroarylation reactions allowed the formation of (Z)-α,β-disubstituted enamides as major compounds in the case of arylynamides and as unique isomer in the case of alkylynamides. The reaction conditions were optimized and the presence of a base was necessary for the efficient preparation of enamides at room temperature. Conversely, α,β-disubstituted or β,β′-disubstituted enamides were isolated as major single stereoisomers and at room temperature in water in the absence of any additive by using PCy3 or P(o-Tol)3, respectively. The best activity was observed for oxazolidin-2-one, whereas other a tosylynamide was non-reactive
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
Experimental results and computational insight into sequential reactions of β-(2-aminophenyl)-α,β-ynones with aryl isocyanates/benzoyl isothiocyanate
No full textThe investigation on tandem addition/cyclization reactions of β-(2-aminophenyl)-α,β-ynones with aryl isocyanates/benzoyl isothiocyanate is reported. Experimental results show the suitable conditions to selectively direct the reaction outcome towards the product of 6-exo-dig N-, O-, or S-annulation of the in situ generated alkynyl urea/thiourea intermediate. The reaction of a variety of β-(2-aminophenyl)-α,β-ynones with aryl isocyanates/benzoyl isothiocyanate led to the selective formation of quinazoline or benzoxazine/benzothiazine derivatives, respectively. Density functional theory calculations provide a plausible rationale for the reaction outcome
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
On Route to Diverse Nitrogen-Bridged Polyhetero-cycles with an N(acyl), N(aryl)-acetal Core
No full textAn expeditious assembling of fused poly-heterocyclic structures having a N(Acyl), N(aryl)-Acetal core has been accomplished by cascade reaction of ortho-functionalized anilines with 2-formylbenzonitrile and subsequent intramolecular N-amidic cyclization on different electrophilic carbons. The syntheses have been finalized using both cathodically-initiated and conventional base-catalyzed methods and comparing the two approaches in terms of substrate/product scope, efficiency, energy-saving and sustainability in general
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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