1,720,960 research outputs found
Absorption spectra of the mono-adduct and the eight bis-addict regioisomers of pyrrolidine derivatives of C60
No full textAbsorption spectra of the pyrrolidine N-mTEG (mTEG1⁄4CH2CH2OCH2CH2OCH2CH2OCH3) mono-adduct and
eight bis-adducts of C60 were studied in the 230–800 nm spectral range. The five-membered ring adducts contain an
apex nitrogen atom. A theoretical discussion in terms of the effective electronic structures and transitions of these
species shows that a filiation between spectra of C60, and its pyrrolidine mono- and bis-adduct derivatives can be expected
and rationalised. Allowed transitions in the ultraviolet are related to fullerene core electronic transitions and are
observed to be little affected in energy and in transition strength by the mono-adduct, apart from band splitting or
broadening associated with the lowered molecular symmetry with respect to C60, whereas in the visible region, the
transitions related to C60 forbidden transitions are significantly modified by the adduct. The bis-adducts have similar
general spectral behaviour to that of the mono-adduct, with differences that reflect the relative position of the two
addends but are found to be not dependent on membership of any of the three formal symmetry groups into which the
bis-adducts can be classified. The second pyrrolidine adduct reinforces the perturbation of the forbidden and, to a lesser
extent, the allowed transitions of the fullerene core. From a comparison with the spectra of C60[C(COOEt)2] and its bisadducts,
it was concluded that the N atom in the pyrrolidine five-membered ring adduct is a less efficient blocker of
through-bond and/or through-space communication than the sp3 carbon atom in Bingel–Hirsch methanofullerenes
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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