1,720,955 research outputs found
An Investigation of Supramolecular Interactions in some Electronically Active Organic and Organometallic Materials
No full textThe opening section of this thesis reviews the application of the concepts of supramolecular chemistry to the control of the solid-state behaviour of organic and organometallic materials. The application of these concepts to our understanding of (i) electronically active salts based on TCNQ and its analogues; and (ii) simple 2,6-disubstituted pyridine derivatives is then reported.Two series of salts have been prepared based on (a) the Mn+ (mnt2-)2) anion and (b) on radialene and triazine analogues of TCNQ.- (TCNQ = 7,7,8,8-tetracyanoquinodimethane). For both these series, counter cations chosen for study were either (i) simple ammonium and pyridinium cations; (ii) cyaninium cations or (iii) ionophore-encapsulated alkali metal cations. Detailed comparison of the solid-state behaviour of these materials has revealed that in addition to electrostatic association, specific C-H......X interactions play an important structure forming role.In a parallel study C-H......X interactions have been found to play a crucial role in the solid-state behaviour of pyridine 2,6-dicarboxylate esters, where a triple interaction of this type leads to the formation of infinite tapes in the solid-state. This contact, a novel supramolecular synthon, is insensitive to the nature of the ester side arms. Preliminary studies on the effect of modifying the nature of this contact are also reported. The analogous pyridine 2,6-dicarboxamides do not show this phenomenon, but prefer a U-shaped conformation which is shown to be ideal for metal ion complexation. In particular 2,6-bis-N,N-(2-pyridylmethyl) pyridine dicarboxamide reacts with nickel (II) and copper (II) to form neutral complexes, which in the latter case are helical. However with cobalt (III) a 2:1 ligand-to-metal complex is formed.</p
Self-assembly into infinite tapes by 2,7-disubstituted-1,8-naphthyridines in the solid state
No full text2,7-Disubstituted-1,8-naphthyridine derivatives have been found to self-assemble into infinite 1-D tapes in the solid state in a manner similar to that seen previously for their 2,6-disubstituted pyridine analogues.<br/
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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