1,720,957 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
Ascorbic acid-pretreated quartz enhances cyclo-oxygenase-2 expression in RAW 264.7 murine macrophages
No full textExposure to quartz particles induces a pathological process named silicosis.Alveolar macrophages initiate the disease through their activation, which isthe origin of the later dysfunctions. Ascorbic acid is known to selectivelydissolve the quartz surface. During the reaction, ascorbic acid progressivelydisappears and hydroxyl radicals are generated from the quartz surface.These observations may be relevant to mammalian quartz toxicity, as sub-stantial amounts of ascorbic acid are present in the lung epithelium. Westudied the inflammatory response of the murine macrophage cell lineRAW 264.7 incubated with ascorbic acid-treated quartz, through theexpression and activity of the enzyme cyclo-oxygenase-2 (COX-2). COX-2expression and prostaglandin secretion were enhanced in cells incubatedwith ascorbic acid-treated quartz. In contrast, no changes were observed incells incubated with Aerosil OX50, an amorphous form of silica. Quantifi-cation of COX-2 mRNA showed a threefold increase in cells incubatedwith ascorbic acid-treated quartz compared with controls. The transcriptionfactors, NF-kB, pCREB and AP-1, were all implicated in the increasedinflammatory response. Reactive oxygen species (H2O2and OH•) wereinvolved in COX-2 expression in this experimental model. Parallel experi-ments performed on rat alveolar macrophages from bronchoalveolar lavageconfirmed the enhanced COX-2 expression and activity in the cells incuba-ted with ascorbic acid-treated quartz compared with untreated quartz. Inconclusion, the selective interaction with, and modification of, quartz parti-cles by ascorbic acid may be a crucial event determining the inflammatoryresponse of macrophages, which may subsequently develop into acute inflammation, eventually leading to the chronic pulmonary disease silicosis
Inibizione selettiva della cicloossigenasi-2 attraverso l’utilizzo di acidi peptidil nucleici in macrofagi murini
No full textAppropriate 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
- …
