1,721,219 research outputs found
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
Hydrogen peroxide produced by anglopoietin-1 mediates angiogenesis-1
No full textAngiopoietin-1 (Ang1) mediates angiogenesis by enhancing endothelial cell survival and migration. It is also known that Ang1 activates Tie2, an endothelial-specific tyrosine kinase receptor, but the molecular mechanism of this process is not clear. In this study, we investigated whether reactive oxygen species (ROS) production plays a role in Ang1-mediated angiogenesis. We found that human umbilical vein endothelial cells treated with Ang1 produce ROS transiently, which was suppressed by NADPH oxidase inhibitor, diphenyleneiodonium chloride, and rotenone. The Ang1-induced ROS was identified as hydrogen peroxide (H2O2) using adenovirus-catalase infection. Removal of H2O2 by adenovirus-catalase significantly suppressed Ang1-induced in vitro endothelial cell migration, in vivo tubule formation and angiogenesis, and activation of p44/42 mitogen-activated protein kinase (MAPK), involved in cell migration, and delayed the deactivation of Akt phosphorylation involved in cell survival. Supporting to in vitro data, Ang1-induced vascular remodeling in catalase (-/-) mice was more prominent than in catalase (+/+) mice: Ang1-induced increases of the diameter of terminal arterioles and the postcapillary venules in catalase (-/-) mice were significant compared with catalase (+/+) mice. These results show that Ang1-induced H2O2 plays an important role in Ang1-mediated angiogenesis by modulating p44/42 MAPK activity
Inhibition of the ERK phosphorylation plays a role in terbinafine-induced p21 up-regulation and DNA synthesis inhibition in human vascular endothelial cells.
No full textDispelling 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
A VOP generation tool: Automatic segmentation of moving objects in image sequences based on spatio-temporal information
No full textThe new MPEG-4 video coding standard enables content-based functionalities. In order to support the philosophy of the MPEG-4 visual standard, each frame of video sequences should be represented in terms of video object planes (VOP's), In other wards, video objects to be encoded in still pictures or video sequences should be prepared before the encoding process starts. Therefore, it requires a prior decomposition of sequences into VOP's so that each VOP represents a moving object, This paper addresses an image segmentation method for separating moving objects from the background in image sequences, The proposed method utilizes the following spatio-temporal information, 1) For localization of moving objects in the image sequence, two consecutive image frames in the temporal direction are examined and a hypothesis testing is performed by comparing two variance estimates from two consecutive difference images, which results in an F-test. 2) Spatial segmentation is performed to divide each image into semantic regions and to find precise object boundaries of the moving objects. The temporal segmentation yields a change detection mask that indicates moving areas (foreground) and nonmoving areas (background), and spatial segmentation produces spatial segmentation masks. A combination of the spatial and temporal segmentation masks produces VOP's faithfully, This paper presents various experimental results
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