1,721,061 research outputs found
Characterisation of the structure, deuterium quadrupolar tensors, and orientational order of acenaphthene, a rigid, prochiral molecule, from the NMR spectra of samples dissolved in nematic and chiral nematic liquid crystalline solvents
No full textMolecules like acenaphthene which have a point group symmetry of C-2v behave as though their symmetry is C-2 when dissolved in chiral nematic liquid crystalline solvents. To quantify this effect a sample of perdeuterated acenaphthene dissolved in the chiral nematic solvent formed by dissolving poly-(gamma -benzyl-L-glutamate), PBLG, in CHCl3 has been studied by deuterium NMR spectroscopy. The quadrupolar splittings obtained were used to determine the orientational order parameters of acenaphthene-d(10) when dissolved in PBLG/CHCl3. To do this it was necessary to also record and analyse the proton and deuterium spectra given by a sample containing both acenaphthene and acenaphthene-d(10) in a non-chiral liquid crystalline solvent. The proton spectrum is very complex, and was analysed only after first recording and analysing the simpler H-1-{H-2} spectrum given by a sample of acenaphthene-d(6). This procedure finally yielded a set of dipolar couplings for the fully protonated molecule, which after correction for vibrational motion, were used to determine both the relative positions of the protons and the orientational order of the molecules. This information was then used to derive the quadrupolar coupling constants from the measured quadrupolar splittings. The lowering of the symmetry of the orientational distribution function is quantified by the angle alpha by which the principal axes of the molecular orientational order matrix of acenaphthene dissolved in PBLG/CHCl3 are rotated out of the plane defined by the aromatic ring. The values of alpha are in the range 1.5 +/- 0.1 degrees to 1.7 +/- 0.1 degrees for the temperature range 295-330 K
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
- …
