1,721,074 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
Fruit consumption reduces the effect of smoking on bladder cancer risk. The Belgian case control study on bladder cancer
No full textWe have hypothesized that consumption of fruit and vegetables may be associated with reduced risk of bladder cancer and that this may interact with cigarette smoking and metabolic genetic polymorphisms. A population-based case-control study was performed in the Belgian province of Limburg among 200 cases and 385 controls. Logistic regression was performed to calculate odds ratios (ORs) for bladder cancer occurrence with corresponding 95% confidence intervals (95% CI). Effect modification by smoking was investigated. We also evaluated interaction between fruit intake and GSTM1, GSTT1, NAT2 and SULT1A1 amongst "ever-smokers." Total vegetable intake was not significantly associated with the risk of bladder cancer (OR 1.15, 95% CI: 0.70-1.88 for the highest compared to the lowest tertile). However, total fruit intake was negatively associated with bladder cancer risk (OR 0.61, 95% CI 0.37-0.99 comparing the same tertiles). Among individuals with low daily fruit consumption, ever smokers had a highly increased risk of bladder cancer risk (OR: 4.23, 95% CI: 1.91-9.40). By increasing the daily fruit consumption, the risk of "ever-smokers" for developing bladder cancer decreased, however it remained significant (OR: 2.15; 95CI%: 1.15-4.05). No interaction was identified between the different genotypes and fruit consumption. We conclude that fruit consumption may decrease the effect of smoking on developing bladder cancer. Antioxidants, found in fruit, may protect against the damage caused by free radicals found in cigarette smoke. Metabolic polymorphisms appear not to modify this relation. (c) 2005 Wiley-Liss, Inc
Empiric risk of prostate carcinoma for relatives of patients with prostate carcinoma: a meta-analysis
No full textEmpiric risk of prostate carcinoma for relatives of patients with prostate carcinoma: a meta-analysis. Zeegers MP, Jellema A, Ostrer H. Department of Epidemiology, Maastricht University, Maastricht, The Netherlands. [email protected] BACKGROUND: Although narrative reviews have concluded that there is strong support for familial clustering of prostate carcinoma, the association has never systematically been quantified in reviews. The purpose of this meta-analysis was to summarize and quantify the recurrence risk ratio with emphasis on the degree of relation, the specific relationship of the family member, the number of affected family members, and the age at diagnosis. METHODS: Publications were identified through computerized database searches for epidemiologic studies published up to December 2002. In addition, references cited in original and review papers were examined. Three blinded reviewers extracted both qualitative and quantitative information from each paper. Using random effects meta-regression analyses, the authors calculated summary recurrence risk ratios (S(lambda)). The reviewers also evaluated changes in S(lambda) according to differences in study methodology. RESULTS: Thirty-three epidemiologic studies were included in the current review. S(lambda) was 2.53 (95% confidence interval, 2.24-2.85) for first-degree family members. S(lambda) appeared to be greater for men with an affected brother than for men with an affected father. S(lambda) for men who had second-degree relatives with prostate carcinoma was only slightly elevated. The nature of the familial clustering is such that S(lambda) increases with decreasing age of the patient and family members, with increasing genetic relatedness of the affected relative, and with increasing number of individuals affected within a family. CONCLUSIONS: The studies that were reviewed consistently demonstrate that family history is a significant risk factor for development of prostate carcinoma. Copyright 2003 American Cancer Societ
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
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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