1,720,956 research outputs found
Pros and cons of three approaches to the study of diffusion in zeolites: cellular automata, Networks and second-order Markov models
Full text linkThe problem of diffusion in zeolites is addressed form different theoretical perspectives, aiming at
building coarse-grained models on the general background of Energy Landscapes theory.A Lattice Gas Cellular Automaton model is applied to the study of mixtures of gas adsorbed in zeolite ITQ-29. A more reductionistic approach, the Central Cell Model, is also presented, with a detailed study of the associated Displacement Autocorrelation Function.The PES of argon, xenon, and methane has been investigated, and represented by means of Disconnectivity Graphs, revealing low kinetic barriers for intra-cage motion at room temperature.The inner space of zeolite pores was coarse-grained, by clustering Molecular Dynamics trajectories, calculating the transition matrix for microstates, and applying Perron Cluster Cluster Analysis, in order to find metastable macrostates. This allowed the fundamental discrete events for diffusing molecules to be defined. On the basis of this events classification, a second-order Markov Model of dynamics was developed, and applied to various adsorbate species in zeolite ITQ-29.Finally, the weighted digraph corresponding to the event transition matrix was analyzed, applying concepts and techniques of Networks Theory
Diffusion of helical particles in the screw-like nematic phase
No full textThe mechanism of diffusion of helical particles in the new screw-like nematic phase is studied by
molecular dynamics numerical simulation. Several dynamical indicators have reported that evidence
and microscopically characterise the special translo-rotational motion by which helical particles move
in this chiral liquid-crystalline phase. Besides mean square displacements and diffusion coefficients
resolved parallel and perpendicular to the nematic director, a suitable translo-rotational van Hove
self-correlation function and a sequence of translational and rotational velocity, self- and distinct-,
time correlation functions are calculated. The analysis of all these correlation functions elicits
the operativeness of the aforementioned coupled mechanism and allows its short- and long-time
quantitative characterisation
Local free energies for the coarse-graining of adsorption phenomena: The interacting pair approximation
No full text
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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