1,720,956 research outputs found
Phase separation, patterning and orientational ordering on closed surfaces: modelling the dynamics of molecules on biological membranes and vesicles
Full text linkWe investigate the dynamics of scalar and vector fields on closed surfaces through the use of numerical algorithms adapted from the literature or freshly developed. The aim of this study is the creation and numerical integration of models for phase separation, pattern formation and emergence of orientational order on biological membranes, as well as the dynamical evolution of the shape of vesicles. We find mechanisms that explain curvature-induced arrest of phase separation, localisation of patterns within certain regions of the membrane; we explore the parameter space of an elastic model of bicomponent vesicles and finally we set up a numerical model to study the time evolution of a nematic fluid on spherical geometry consistent with the expected behaviour of the field
Curvature-driven positioning of Turing patterns in phase-separating curved membranes
No full textWe introduce a new finite difference scheme to study the dynamics of Turing patterns of a two-species activator-inhibitor system embedded on a phase-separating curved membrane, modelling for instance a lipid bilayer. We show that the underlying binary fluid can strongly affect both the dynamical and the steady state properties of the ensuing Turing patterns. Furthermore, geometry plays a key role, as a large enough local membrane curvature can both arrest the coarsening of the lipid domains and position the patterns selectively at areas of high or small local curvature. The physical phenomena we observe are due to a minimal coupling, between the diffusivity of the Turing components and the local membrane composition. While our study is theoretical in nature, it can provide a framework within which to address intracellular pattern formation in systems of interacting membrane proteins. © 2016 The Royal Society of Chemistry
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
Analisi del flusso bifase nell'elemento tergipavimento di una macchina lavasciuga pavimenti
No full textSi progetta e sviluppa un apparato sperimentale per visualizzare il flusso d'acqua nel tergipavimento di una macchina lavasciuga pavimenti. I dati ottenuti si utilizzano per descrivere i regimi di flusso bifase acqua-aria, e per validare i risultati prodotti da simulazioni numeriche eseguite sulle geometrie di tergipavimento testate. I risultati danno un buon accordo tra modello numerico ed esperimenti, e forniscono linee guida per la riprogettazione di un futuro tergipavimento più efficiente
Analisi del flusso bifase nell'elemento tergipavimento di una macchina lavasciuga pavimenti
Full text linkSi progetta e sviluppa un apparato sperimentale per visualizzare il flusso d'acqua nel tergipavimento di una macchina lavasciuga pavimenti. I dati ottenuti si utilizzano per descrivere i regimi di flusso bifase acqua-aria, e per validare i risultati prodotti da simulazioni numeriche eseguite sulle geometrie di tergipavimento testate. I risultati danno un buon accordo tra modello numerico ed esperimenti, e forniscono linee guida per la riprogettazione di un futuro tergipavimento più efficiente.openEmbargo temporaneo per motivi di segretezza e/o di proprietà dei risultati e informazioni di enti esterni o aziende private che hanno partecipato alla realizzazione del lavoro di ricerca relativo alla tes
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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