1,721,062 research outputs found
The effects of P-T changes on intermolecular interactions in crystal structure of iodoform
Full text linkThe structural transition at different pressures of a halogen and
hydrogen bonded molecular structure (iodoform, CHI3) is described. The
pressures analyzed up to sample decomposition are 0.85 GPa (P1RT) and
2.15 GPa (P2RT); also room conditions (PORT) and low temperature (106 K,
POLT) structures have been reported for comparison. The observed
disorder-order phase transition, from P6(3)/m to P6(3) space group, can
be rationalized by the intermolecular interaction analysis. The
shortening of the distances among iodoform planes, observed during the
compression and the temperature decreasing, determines an ordering of
molecular dipoles in a parallel arrangement: this phase transition
causes a shortening of I center dot center dot center dot I halogen
bondings. The BSSE corrected cohesive energies have been calculated for
all structures at DFT/B3LYP level of theory using a periodic boundary
condition code and the Grimme dispersion correction. Hirshfeld surfaces
and electrostatic potential mapped on charge density isosurfaces have
been computed and their features have been analyzed, in order to better
understand the halogen intermolecular interactions that control the
structural modification of iodoform crystal. (C) 2013 Elsevier B.V. All
rights reserved
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
Metamorphic zonation, migmatization and leucogranites along the Everest transect of Eastern Nepal and Tibet: record of an exhumation history
No full textVariations 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
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