1,721,085 research outputs found
Active Ising Models of Flocking: A Field-Theoretic Approach
Full text linkUsing an approach based on Doi-Peliti field theory, we study several
different Active Ising Models (AIMs), in each of which collective motion
(flocking) of self-propelled particles arises from the spontaneous breaking of
a discrete symmetry. We test the predictive power of our field theories by
deriving the hydrodynamic equations for the different microscopic choices of
aligning processes that define our various models. At deterministic level, the
resulting equations largely confirm known results, but our approach has the
advantage of allowing systematic generalization to include noise terms. Study
of the resulting hydrodynamics allows us to confirm that the various AIMs share
the same phenomenology of a first order transition from isotropic to flocked
states whenever the self propulsion speed is nonzero, with an important
exception for the case where particles align only pairwise locally. Remarkably,
this variant fails entirely to give flocking -- an outcome that was foreseen in
previous work, but is confirmed here and explained in terms of the scalings of
various terms in the hydrodynamic limit. Finally, we discuss our AIMs in the
limit of zero self-propulsion where the ordering transition is continuous. In
this limit, each model is still out of equilibrium because the dynamical rules
continue to break detailed balance, yet it has been argued that an equilibrium
universality class (Model C) prevails. We study field-theoretically the
connection between our AIMs and Model C, arguing that these particular models
(though not AIMs in general) lie outside the Model C class. We link this to the
fact that in our AIMs without self propulsion, detailed balance is not merely
still broken, but replaced by a different dynamical symmetry in which the
dynamics of the particle density is independent of the spin state.Comment: 16+8 page
Statistical properties of microphase and bubbly phase-separated active fluids
No full textHorizon 2020 http://dx.doi.org/10.13039/501100007601Agence Nationale de la Recherche http://dx.doi.org/10.13039/501100001665European Research Council http://dx.doi.org/10.13039/501100000781National Science Foundation http://dx.doi.org/10.13039/100000001Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266Simons Foundation http://dx.doi.org/10.13039/10000089
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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