1,721,543 research outputs found
Moving object detection and tracking from MPEG coded Picture
No full text@inproceedings{CN-CHAHIR-2002, author = {Cai, G. and Chahir, Y. and Li, J.}, title = {Moving object detection and tracking from MPEG coded Picture}, booktitle = {Journées Francophones D'Accès Intelligent aux Documents Multimédias sur l'Internet}, pages = {355-363}, year = {2002}, address = {Sousse, Tunisie} }National audienc
How do microtubules affect the deposition of cell wall polysaccharides in the pollen tube?
No full textCallose is the primary polysaccharidepresent in the so-called secondarylayer of the pollen tube cell wall whilethe content of cellulose in such layer isusually lower. Despite its lower quantity,cellulose might be potentially able toestablish the growth direction of pollentubes. Microtubules have been shown toregulate the deposition of callose synthasein the distal regions of pollen tubesrelated to the synthesis of callose plugs.However, the interplay between microtubulesand cellulose synthase in the pollentube is unclear. Here, the hypotheticalrole of microtubules and microtubulebasedmotor proteins in controlling theinsertion of cellulose synthase in relationwith growth and directionality of pollentubes is discussed. © 2011 Landes Bioscience
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
Pollen tube and plant reproduction
Full text linkThe pollen tube was a fundamental step forward in the evolution of terrestrial plants; in fact,
it allowed plants to liberate themselves from water demand during reproduction. The importance
of this simple organism (the plant gametophyte) is also due to its peculiar cytological structure,
characterized by tip growth and a cell wall that is not canonically structured but perfectly adapted to
the growth mechanism. Being both a critical factor in sexual reproduction and an excellent cell model
has made the pollen tube attractive to many researchers around the world. The growth of pollen tubes
is a complex mechanism that summarizes the basic machineries of cellular expansion: polysaccharides
and enzymes are transported by secretory vesicles to a specific location, a set of molecules and proteins
translate external signals that influence the cytoskeleton of pollen tubes and thus its growth direction
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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