1,720,965 research outputs found
Meta-analyses of published epidemiological studies, 1979-2006, point to open causal questions in silica-silicosis-lung cancer research
No full textBACKGROUND AND OBJECTIVES:
Following up on a previous meta-analysis of lung cancer risk in individuals without silicosis, we provide more detailed results of silica associated lung cancer risk in both silicotics and non-silicotics. The objective was to examine in depth whether current data allows to answer the pressing question "does silica cause lung cancer in the absence of silicosis"?
METHODS:
We updated earlier meta-analyses of silicosis and lung cancer and compared the results with our 2009 meta-analysis of risks in individuals without silicosis. We performed fixed (FE) and random (RE) effects meta-analyses, calculated heterogeneity statistics, stratified the study material, performed sensitivity analyses with modified study results and meta-regressions to detect effect modification.
RESULTS:
In silicotics, lung cancer risks were found to be doubled in 38 studies (FE: RR = 2.1; 95% CI = 2.0-2.3). In non-silicotics, eight studies without smoking adjustment suggested marginally elevated risks (FE: RR = 1.2; 95% CI = 1.1-1.3; RE: RR = 1.2; 95% CI =1.0-1.4) but three studies which were controlled for smoking showed null results (FE and RE: RR = 1.0; 95% CI = 0.8-1.3). Heterogeneity was substantial but could be linked to study characteristics, like sector of industry, and other second-level data in meta-regression. As no excess was observe dfor other smoking-related effects in studies ofllung cancer among non-silicotics, smoking was not considered to be an important confounder or modifier. CONCLUSIONn: Our meta-analyses further substantiate evidence of a strong association between silicosis and lung cancer. However, questions remain regarding lung cancer caused by silica in non-silicotics. Ideally, future investigations should consider the entire exposure-response range between silica exposure, silicosis development and lung cancer occurrence, and analyze data in terms of processes taking intermediate confounding into account
RE “Invited commentary: electromagnetic fields and cancer in railway workers”. EMF dosimetry by geography. Beyond black box epidemiology
No full textIs light a risk factor for internal cancers? – Rationale for a study based on light dosimetry by geography
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Does light cause internal cancers? - The challenge to study an ubiquitous exposure epidemiologically
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Urinary 6-sulfatoxymelatonin excretion in humans during domestic exposure to 50 hertz electromagnetic fields.
No full textOBJECTIVES: Exposure to extremely low frequency electromagnetic fields (ELF-EMF) has been suggested to suppress melatonin secretion, which might result in higher cancer risks because of its missing oncostatic action. We investigated the effects of residential exposure to ELF-EMF on the excretion of urinary 6-sulfatoxymelatonin (6-OHMS), the major melatonin metabolite, as an indicator of nocturnal melatonin secretion.
METHODS: 6-OHMS was measured in two spot urine samples, collected at 22.00 h and 08.00 h, in 29 men and 22 women. Spot ELF-EMF measurements were conducted at the centre and the four angles of the living room, the bedroom, and the kitchen of study subjects at low current configuration (all lights and appliances turned off), and they were repeated immediately at high current configuration (all lights and appliances turned on).
RESULTS: Risk of a reduced 6-OMHS nocturnal secretion was elevated for daily alcohol intake (OR = 6.4; 95%C.I. 1.4,33.1), and body mass index (BMI) above the median (OR = 2.2; 95%C.I. 0.5,9.6). Risk of disrupted rhythm of 6-OHMS excretion was moderately elevated for domestic ELF-EMF exposure above the upper tertile at low current configuration (OR = 2.6; 95%C.I. 0.4,15.7).
CONCLUSION: Alcohol consumption, BMI, and gender seem to affect nocturnal melatonin secretion, while an effect of residential exposure to ELF-EMF is uncertain. Future studies should properly account for the effect of such variables, when addressing the hypothesis of disturbances in melatonin secretion as a plausible explanation for the reported excess risk of several tumoral diseases associated with low level ELF-EMF exposure
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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