1,721,023 research outputs found
Phase separation dynamics on curved surfaces
No full textIn this work we present computer simulations of the dynamics of phase separation of a binary fluid on a variety of curved surfaces. The geometries considered range from sphere to ellipsoid, to models for budding cells, described as spheres with a bump. We study both the case in which there is no coupling between curvature and local composition, and the situation in which one of the two fluids, or lipids, prefers, or avoids, highly curved regions on the surface. Our results show that in these two cases there is a distinct difference in both the kinetic pathway to lipid sorting and the final localisation of the domains formed. Highlighting these differences should be useful, we expect, to discriminate between different theories for domain formation in a biophysical context
Polymers with spatial or topological constraints: Theoretical and computational results
No full textcomputational results that are available for polymers subject to spatial
or topological constraints. Because of the interdisciplinary character
of the topic, we provide an accessible, non-specialist introduction to
the main topological concepts, polymer models, and
theoretical/computational methods used to investigate dense and
entangled polymer systems. The main body of our review deals with (i)
the effect that spatial confinement has on the equilibrium topological
entanglement of one or more polymer chains and (ii) the metric and
entropic properties of polymer chains with fixed topological states.
These problems have important technological applications and
implications for life sciences. Both aspects, especially the latter, are
amply covered. A number of selected open problems are finally
highlighted. (C) 2011 Elsevier B.V. All rights reserved
Monte Carlo and event-driven dynamics of Brownian particles with orientational degrees of freedom
Full text linkRecently, a simple scaling argument was introduced that allows us to map, with some precautions, Brownian and Monte Carlo dynamics for spherical particles. Here, we extend the scaling to study systems that have orientational degrees of freedom and carefully asses its validity over a wide region of temperature and density. Our work allows us to devise a Brownian Monte Carlo algorithm that produces, to a good approximation, physically meaningful trajectories with a minimum programming effort, although at the expense of some sampling efficiency
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
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