1,721,063 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
Gestational trophoblastic neoplasms in homozygous twins
No full textThe occurrence of gestational trophoblastic disease in homozygous twins is described. The correlation between this finding and current genetic hypotheses on the pathogenesis of hydatidiform mole is considered
The epidemiology of ovarian cancer
No full textThe descriptive and analytical epidemiology of ovarian cancer is reviewed, starting from the substantial geographical differences, with high rates in North America and Europe and low rates in developing countries and Japan, although, on a worldwide scale, almost 50% of 140,000 total cases occur in developing countries. Over the past decades, incidence and mortality rates have remained approximately stable in high-risk areas, but have generally tended to rise in low-risk areas. In the past, ovarian cancer was more common in higher social classes, but sociocultural differences seem to have flattened off over recent decades. In etiological terms, the protection afforded by multiparity and oral contraceptive (OC) use is well established, with relative risks (RRs) of the order of 0.5 for multiparae and OC users. There is also consistent evidence that risk increases with late age at menopause. Less consistent and weak, if any, are the effects of age at menarche and first birth, although there is hint that a first birth over age 35 is not protective. It is conceivable that diet can play an important role in ovarian carcinogenesis, but only scattered data are available to suggest that high fat consumption may represent an indicator of risk. Available knowledge on ovarian cancer epidemiology is also discussed in relation to models of carcinogenesis and implications for prevention and public health
Post-coital contraception : an overview of published studies
No full textInformation from published studies testing the effect of hormonal and mechanical interceptive methods in post-coital contraception was pooled with the aim of assessing the efficacy of various regimens. The pooled failure rates were 0.6% (19/3168 based on four studies) for high-dosage ethinylestradiol, 1.1% (11/975, based on two studies) for other high-dose estrogens, 1.8% (69/3802 based on 11 studies) for combined estro-progestin preparations, 2.0% (20/998 based on three studies) for danazol and 0.1% (1/879 based on nine studies) for intra-uterine devices (IUD). Although this overview has several limitations in terms of over-representation of optimistic results in the literature or absence of direct comparison between treatments in several studies, it suggests that IUD and high-dose ethinylestradiol are more efficacious forms of post-coital contraception than danazol or combined contraceptives
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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