1,720,967 research outputs found
Severe mitral valve stenosis due to a giant left atrial mass
No full textSevere mitral valve stenosis due to a giant left atrial mass
Kirkwood-Buff integrals for polymer-solvent mixtures. Preferential solvation and volumetric analysis in aqueous PEG solutions.
No full textLysozyme mutual diffusion in solutions crowded by poly(ethylene glycol)
No full textMutual diffusion in a multicomponent system at high level of macromolecular crowding has been investigated for a solution containing a protein and a polymeric precipitant. Specifically, precise mutual diffusion coefficients for the ternary system lysozyme (component 1)-PEG2000 (component 2)-water (component 0) up to 25% in volume of PEG have been determined via Gouy interferometry. Experimental diffusion data, Dij, are compared to those predicted by two semiemprirical equations, which are discussed according to the physics behind them. Dij values are used to analyze the gravitational stability of the protein-polymer aqueous solution, and, in combination with the Onsager reciprocal relations, to evaluate the lysozyme salting out coefficient for addition of PEG (í12). Experimental í12 are in good agreement with those predicted by Lekkerkerker’s equation. All the results have been compared to those corresponding, previously determined, for a companion system containing a PEG sample at a different molecular weight, PEG400. The influence of PEG-induced crowding on proteins in physiological or in crystallization media has been discusse
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
A diffusion study on the ternary system, sodium cholate–sodium deoxycholate–water
No full textThe mutual diffusion coefficients, Dij, of the ternary system sodium cholate (NaC, component 1)+sodium
deoxycholate (NadC, component 2)+water have been determined at five average compositions (c1, c2)
keeping c1 constant and varying c2. The possibility to obtain expressions for the four diffusion coefficients in
term of the micellization parameters and of the diffusivity of the species in solution is discussed. Data have
been qualitatively interpreted. Results for the main term diffusion coefficients have been used in the much
more difficult analysis of the cross term diffusion coefficients
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