1,721,428 research outputs found
studies of the internal rotation of ethylene in the Ar-ethylene and Ne-ethylene van der Waals complexes
No full textRotational spectra of the weakly bound complexes Ar-ethylene and Ne-ethylene were measured with a pulsed molecular beam Fourier transform microwave spectrometer in the range from 3.5 to 26 GHz. Spectra of five isotopomers of Ar-ethylene, namely Ar-C2H4, Ar-(C2H4)-C-13, Ar-C2D4, Ar-trans-1,2-C2D2H2, and Ar-cis-1,2-C2D2H2, and of eight isotopomers of Ne-ethylene, namely Ne-20-C2H4, Ne-20-C2D4, Ne-20-trans-1,2-C2D2H2, Ne-20-cis-1,2-C2D2H2, Ne-22-C2H4, Ne-22-C2D4, Ne-22-trans-1,2-C2D2H2, and Ne-22-cis-1,2-C2D2H2, were assigned and analyzed. The spectra are in accord with T-shaped, planar structures, where the rage gas atoms are located on the b-principal inertial axis of the ethylene monomer. For isotopomers containing C2H4, (C2H4)-C-13, C2D4, and trans-1,2-C2D2H2, all observed transitions are doubled due to an internal rotation motion of the ethylene subunit within the complexes. The observed transition intensities are in agreement with nuclear spin statistical weights obtained from molecular symmetry group analyses under the assumption of an internal rotation of the ethylene unit about the C=C bond, i.e., the out-of-plane motion. The observation of K-a=1, m=0 transitions in Ne-trans-1,2-C2D2H2 provides further proof that the out-of-plane motion is responsible for the observed tunneling splittings. Information about the energy level ordering of the K-a=1, m=0 and K-a=0, m=1 states was obtained from the rotational spectra of the Ne-trans-1,2-C2D2H2 isotopomers. Electronic structure calculations of Ne-C2H4 were done at the CCSD(T) level of theory with the aug-cc-pVTZ basis set for all atoms, supplemented with bond functions. The global minimum is at the T-shaped, planar configuration, with a distance of R=3.55 A between the Ne atom and the center-of-mass of ethylene and a well depth of -81.5 cm-1. One-dimensional minimum potential energy paths for possible internal rotation motions were determined. The results confirm that the out-of-plane motion is the preferred internal motion. The out-of-plane minimum potential energy path was used to determine the energy difference between the two lowest tunneling states using the one-dimensional flexible model by Meyer [R. Meyer, J. Mol. Spectrosc. 76, 266 (1979)]. (C) 2003 American Institute of Physics
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
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