1,720,965 research outputs found
Calculation of relative risk using ordinary logistic regression with the doubling-of-cases method
No full textLa investigación clínica y epidemiológica examina asociaciones entre diversas exposiciones y eventos de interés. En estudios con diseño prospectivo, el riesgo relativo (RR) es una medida comúnmente utilizada para expresar los resultados. No obstante, para controlar o ajustar variables confundentes, es necesario recurrir a modelos de regresión, siendo el modelo de regresión logística binaria el más empleado. Sin embargo, este modelo calcula odds ratios (OR), que bajo ciertas circunstancias pueden sobreestimar el RR, lo que puede llevar a una valoración inadecuada del tamaño del efecto de la exposición. Este artículo, de carácter docente, describe aspectos epi-demiológicos y matemáticos del método de duplicación de casos (doubling-of-cases method), una alternativa simple y novedosa para estimar el RR utilizando un modelo de regresión logística binaria, evitando la sobreestimación del tamaño del efecto de la exposició
Seasonal variation of acute myocardial infarction deaths in Chile
No full textBackground: Hospitalization and deaths due to cardiovascular diseases (CVD), have a peak in frequency during winter.Aim:To assess the existence of seasonal variation in deaths due to acute myocardial infarction (AMI) in Chile.Material and Methods:Analysis of death report databases available at the website of the Chilean Ministry of Health. The seasonality of deaths due to AMI (codes ICD-10 I21, I22, I23) occuring in Chile between 2001-2016 were analyzed using a geometric model assuming a sinusoidal cyclic pattern.Results:During the period 2001-2016, a total of 94,788 deaths due to AMI were registered, corresponding to 93,349 corrected deaths. Of the latter, 29.2% occurred in winter, 24.9% in spring, 24.0% in autumn and 21.8% in summer. The geometric model showed a marked sinusoidal pattern for the aggregated data. The peak-to-low ratio of deaths was 1.41 (95% CI 1.38-1.44). The peak of deaths occurred during July in 14 out of 16 years analyzed.Conclusions:In Chile, deaths due to AMI have a marked seasonal pattern, characterized by a higher number of deaths in winter and a lower number in summer
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
