1,720,995 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
Stimulatory effect of PG-KII, an NK3 tachykinin receptor agonist, on isolated pancreatic acini: species-related differences
No full textMore information is needed on the physiological role of the tachykinins (TKs), especially neurokinin(3)-receptor (NK3) agonists, in the pancreas. In this paper we investigated and compared the effect of PG-KII (10(-9) to 10(-6) M), a natural NK3-receptor agonist, with that of the known secretagogues substance P (10(-9) to 10(-6) M), caerulein (10-(11) to 10(-8) M) and carbachol (10(-8) to 10(-5) M), on amylase secretion from dispersed pancreatic acini of the guinea pig and rat. PG-KII (10(-7) M) significantly increased basal amylase release from guinea pig pancreatic acini (from 5.4 +/- 0.9% to 11.3 +/- 0.5%, P < 0.05) but left basal release in the rat unchanged (6.5 &PLUSMN; 0.5%). The stimulant effect of PG-KII on guinea pig acini was significantly reduced by the NK3-receptor antagonist, SR 142801 (5 x 10(-7) M), and left unchanged by the NK1-receptor antagonist, SR 140333 (5 x 10(-7) M). Conversely, substance p (10(-7) M) significantly stimulated amylase secretion from rat and guinea pig acini (12.6 &PLUSMN; 0.6% and 12.1 &PLUSMN; 0.7%, P < 0.05). This stimulated effect of substance P was antagonized by the NK1-receptor antagonist (5 x 10(-7) M), but not by the NK3-receptor antagonist (5 x 10(-7) M). The PG-KII- and substance P-evoked maximal responses were lower than those evoked by caerulein (10(-9) M) (guinea pig, 19.1 +/- 1.3%; rat, 18.2 +/- 0.9%, P < 0.01) and carbachol (10(-5) M) (guinea pig, 23.3 &PLUSMN; 1.2%; rat, 24.0 &PLUSMN; 1.1%, P < 0.01). The inhibitors of phospholipase CU-73122 (10(-5) M), phospholipase A(2) quinacrine (10(-5) M), and protein tyrosine kinase genistein (10(-4) M), partly but significantly inhibited PG-KII, as well as carbachol-stimulated amylase release. Coincubation of PG-KII 10(-7) M with submaximal doses of caerulein (10(-11) to 10(-10) M) and carbachol (10(-7) to 10(-6) M) had an additive effect on amylase release. Pre-incubation with PG-KII (10(-7) M) for 30 min significantly reduced the subsequent amylase response to PG-KII, whereas pre-incubation with caerulein 10(-10) M or carbachol 10(-6) M did not. These findings suggest that PG-KII directly contributes to pancreatic exocrine secretion by interacting with acinar NK3 receptors of the guinea pig but not of the rat. PG-KII signal transduction involves the intracellular phospholipase C, phospholipase A2 and protein tyrosine kinase pathways. The NK3 receptor system cooperates with the other known secretagogues in regulating guinea pig exocrine pancreatic secretion and undergoes rapid homologous desensitization. (C) 2003 Elsevier Inc. All rights reserved
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