1,720,992 research outputs found
EVOLUTION AND STABILITY OF SELF-LOCALIZED MODES IN A NONLINEAR INHOMOGENEOUS CRYSTAL-LATTICE
No full textThe evolution and stability of self-localized modes in an inhomogeneous crystal lattice are discussed. After establishing the basic equations, appropriate time and space scales are introduced, together with a power threshold. A mathematical stability theory, based upon an averaged Lagrangian analysis, concludes that the system is stable for any mass defect, if the perturbation is symmetric. For asymmetric perturbations, only single-peaked stationary states are stable. Finally, numerical simulations are presented that not only support the theoretical work of the earlier sections but show clearly the evolution of the solutions from a range of input conditions
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
Aspects of metamaterial structures : theory and simulation
No full textThe investigations reported here address the issue of overcoming loss in a typicalisotropic metamaterial. The possibility of adding functionality to such materials,through gyrotropic effects, and diffraction management of nonlinear beams, driven bynegative phase accumulation, is presented. Loss is overcome by the introduction ofgain to the metamaterial. This is achieved on the basis that typical split-ringmetaparticles can be suitably enhanced through the addition of carefully selecteddiodes. The detailed analysis given here deploys a familiar equivalent circuit modeland specific current-voltage characteristics. It is emphasised that conditions must bein place to ensure overall stable material behaviour. The methodology uses convectiveand absolute instability concepts and it is shown that the latter can be so detrimentalas to lead to a much reduced frequency window of operation. Another set ofinvestigations emphasises that surface waves provide a path to new science.Consequently the propagation of surface waves along the interface between ametamaterial and a gyrotropic medium is promising for applications. Theinvestigation outcomes of this complicated system need to demonstrate generationproperties in real time. Hence, some unique finite-difference time-domain (FDTD)computations have been developed enabling their interesting connection to the Goos-Hanchen shift to be elegantly displayed. Many interesting forms of surface waves arediscussed including the simultaneous generation of TE and TM waves propagating inopposite directions. It is well known that in an isotropic metamaterial backwardwaves can exist so this property is exploited to create a fascinating form of diffractionmanagement. This is investigated both for the bulk and for cavities and the impact ofwhat is defined as nonlinear diffraction is introduced. Finally, some magnetooptics isintroduced that adds even more functionality to the generation of cavity solitons
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
Fluorescence enhancement using Fano-resonant a plasmonic nanostructure with selective functionalization of molecules at the electromagnetic hot spot
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