1,720,982 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
Liver expression of hepcidin and other iron genes in two mouse models of beta-thalassemia
No full textBackground and Objectives. Homozygous b-thalassemia patients may develop iron
overload even if untransfused, due to inappropriately high intestinal iron absorption.
Reduction of hepcidin synthesis has been reported both in patients and in animal models.
We have measured liver hepcidin and other iron gene transcripts in two different
mouse models of b-thalassemia at different ages.
Design and Methods. Mice Hbbth/th, characterized by spontaneous homozygous deletion
of the major b1 globin gene were studied at 2 and 8 months. Mice Hbbth3/+, characterized
by the heterozygous deletion of b1 and b2 globin genes were studied at 4 and 10
months. Hematologic data were obtained and iron overload estimated by Perls’ staining
of the liver. Expression of liver hepcidin, Tfr2, Hjv, Fpn and Hfe RNA was assessed
by real-time polymerase chain reaction. Levels of serum cytokines (interleukin-6, IL-1b,
IL-10, granulocyte-macrophage colony-stimulating factor) levels were assayed by
enzyme-linked immunosorbent assay.
Results. Hemoglobin, hematocrit and mean corpuscolar volume were significantly
reduced in both b-thalassemia models, more significantly in Hbbth3/+, which have the
greater, age-dependent, iron overload. Hepcidin RNA was not increased despite iron
overload in both strains. Fpn RNA was increased and Tfr2 was decreased in older animals.
Inflammatory cytokine levels were striking variable and unrelated to hepcidin levels.
Interpretation and Conclusions. Although anemia is reported to inhibit hepcidin expression,
normal hepcidin synthesis was maintained in both thalassemic models studied.
However, hepcidin levels were inappropriate for the body iron, especially in Hbbth3/+ 10-
month-old animals. As we previously reported in wild type mice after parenteral iron
overload, Tfr2 is reduced and Fpn RNA increased in thalassemic mice. Inflammatory
cytokines did not play a major role in increasing hepcidin levels or in modifying iron
homeostasis in this stud
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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