1,720,960 research outputs found
Dynamics of vortices on a uniformly shelving beach
No full textLaboratory experiments are described which investigate the dynamics of a vortex dipole moving in water towards a planar sloping beach inclined at an angle [alpha] to the horizontal. Results are compared with those of a vortex ring model first developed by Peregrine (1996). The vortices separate as they travel up the beach, eventually moving in opposite directions and nearly parallel to the shoreline. The ranges of conditions examined are 3°[less-than-or-eq, slant][alpha][less-than-or-eq, slant]45°, 1×103[less-than-or-eq, slant]Re[less-than-or-eq, slant]6×103 and 0.05[less-than-or-eq, slant]Fr[less-than-or-eq, slant]0.14, where Re and Fr are the on-slope Reynolds number and the Froude number of the vortices, respectively. The minimum distance from the shoreline reached by the vortices and their along-shore speed are in general agreement with the predictions when, respectively, R*i<3 (where R*i is the non-dimensional initial distance of the vortices from the shore-line) and Re[greater, similar]1500. The vortex ring model is likely to have useful applications to the study of the dynamics of the near-shore zone
Dynamics of near-shore vortices
No full textThis work addresses two problems: 1) the dispersion induced by a cloud of vortices near a straight coast-line when the bottom is flat and the coastal boundary is a vertical plane or when the bottom is a planar slope; 2) the dynamics of vortices moving over a planar sloping bottom. Vortices near a vertical boundary are studied by the well-known method of images. For a plane sloping bottom we describe and develop a model, first introduced by Peregrine (1996) that uses a sector of a vortex ring to model a vortex in a wedge of fluid, where the wedge is formed by the water surface and by the planar sloping bottom. Numerical simulations using these free-slip analytical models are used to investigate the dispersion of vorticity and of a passive tracer induced by clouds of vortices. The results of the two models are compared. The dispersion of vortices and particles is mainly affected by the formation of vortex dipoles. The shoreline sets a preferential direction for the dispersion process and the dispersion normal to the shoreline is generally smaller, or bounded when the vortices forming the dipole have different absolute circulation. The dispersion of particles is generally smaller than the dispersion of vortices. In the second part of this work the analytical model of Peregrine (1996) for vortices moving over a planar slope at an angle a with the horizontal is tested against a set of laboratory experiments. Experiments were made by studying the dynamics of a vortex dipole moving towards a planar sloping beach. We measured the minimum distance from the shoreline reached by the vortices and their along-shore speed. The parameter ranges examined were 3º≤α≤45º, and 1×103≤Re≤6×103 (where Re is the Reynold's number of the vortices). We find a good agreement between the predictions and the observations when Re >~ 1500
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
