1,721,240 research outputs found
INTEROCC : Occupational exposure assessment for electromagnetic fields and risk of brain tumours. Development of a new source-based approach
No full textIntroducción: Con el fin de mejorar los métodos de evaluación de la exposición a campos electromagnéticos, desarrollamos un nuevo método basado en fuentes de exposición en lugar de códigos de ocupación. Mediciones obtenidas de la bibliografía fueron recopiladas, evaluadas y compiladas en una base de datos para ser posteriormente combinadas en forma de una matriz fuente-exposición. Esta matriz, junto a otros determinantes de la exposición, fue usada para calcular índices de exposición acumulada. El riesgo de mayor incidencia de tumores cerebrales, glioma y meningioma, se analizó usando estas estimaciones acumuladas. Los resultados del análisis mostraron un ligero incremento del riesgo de glioma en los grupos de trabajadores más expuestos a campos electromagnéticos de alta frecuencia en las ventanas de exposición más cercanas a la fecha de diagnóstico/referencia y en todas las ventanas para meningioma. En campos de frecuencia intermedia, se encontraron ligeros aumentos de riesgo solo en glioma en las ventanas de exposición más recientes. Estos resultados pueden reflejar que los campos electromagnéticos de alta frecuencia pueden tener un papel en las etapas más tardías de la carcinogénesis (promoción y progresión)Introduction: To improve exposure assessment methods for electromagnetic fields, we developed a methodology based on sources of exposure rather than job titles. Methods: Measurements collected from the literature were assessed and summarized into a source-exposure matrix (SEM). The SEM and personal determinants of exposure were combined to obtain individual indices cumulative exposure, which were used to assess risk of brain tumours, glioma an meningioma Results: Over 3,000 records were obtained and judged useful, creating a SEM with exposure estimates for 312 EMF sources. Overall the analysis yielded no association between glioma or meningioma risk and cumulative exposure to RF or IF EMF. However, some positive associations were identified for RF and IF EMF in the highest exposed groups in the 1- to 4-year exposure window for glioma, and in all windows for meningioma and RF only. These results might reflect a possible role of high frequency EMF in the later stages of carcinogenesis (promotion and progression).Programa de doctorat en Biomedicin
CT scans in children and young adults and cancer risk: the Spanish EPI-CT cohort
No full textThe present thesis introduces the EPI-CT cohort study; a European collaborative effort aimed at quantifying the health risks of computed tomography (CT scan) radiation exposure during childhood and assesses the main epidemiological factors that could bias the risk estimates in similar studies. It confirms an increase in the CT scan usage among patients younger than 21 years in Catalonia during the period 1991-2013. Of importance is that, the results obtained within the Spanish branch of the EPI-CT study do not suggest that the number of CT scans per person differ among the socioeconomic spectrum. This thesis also includes a health risk assessment of the 2013 Spanish CT imaging practice in young population, which projects 0.2% additional cancer cases (over the spontaneously arising cancer cases) to occur in the expected lifespan of the CT scan exposed individuals. A very initial analysis quantifying the association between the cumulative organ-doses and leukaemia and brain cancer mortality is included, suggesting a dose-related increase in the risk of brain tumours and leukaemia mortality.Aquesta tesi presenta l'estudi de cohort EPI-CT; un estudi Europeu adreçat a la quantificació dels riscos per a la salut associats a l'exposició a la radiació de la tomografia computaritzada (TC) durant la infància i avalua els principals factors epidemiològics que podrien esbiaixar les estimacions de risc en estudis similars. Aquesta tesi confirma un augment en l'ús de la TC en pacients menors de 21 anys a Catalunya durant el període 1991-2013 i alhora, conclou que el nombre de TCs per persona no difereix segons el nivell socioeconòmic del pacient, suggerint un ús similar en tota la població. Aquesta tesi inclou també una avaluació del risc per a la salut de totes les TCs que es van dur a terme al 2013 en població jove a Espanya, i projecta un increment d’un 0,2% de càncers respecte als que s’esperen que ocorrin de forma espontànea entre la població exposada. S’inclou també una anàlisi molt inicial en la que s’observa una associació entre dosi a nivell d’òrgan i mortalitat per leucèmia i càncer de cervell.Programa de doctorat en Biomedicin
Cancer risk among children exposed to medical ionising radiation and modifying factors - evidence from paediatric CT exposure in Sweden
No full textThough Computed Tomography (CT) plays an essential role in healthcare, several large-scale cohort studies have reported an increased cancer risk following CT-radiation exposure in childhood. Results may be subject to confounding, reverse causation and exposure misclassification. We aimed to better understand cancer effects of childhood CT exposure through an analysis of cancer risk and CT trends in a large-scale cohort study in Sweden, a review of evidence regarding possible modifying effects of cancer predisposing factors and a nested case-control study to address potential biases in cohort studies. An increased risk of cancer and haematological malignancies was found in the Swedish study compared to the general population. CT frequency was found to decrease, however, over time. Limited evidence was found that CPFs modify radiation induced cancer risk. The nested case- control study suggests that the haematological malignancy risk in cohort studies may be affected by missing doses from other radiological procedures. These results add to the body of evidence concerning CTs and cancer and underline the need for strict justification of paediatric CTs.La tomografía computarizada (TC) desempeña un papel esencial en la asistencia sanitaria. Sin embargo, varios estudios de cohortes a gran escala han notificado un aumento del riesgo de padecer cáncer tras la exposición a la radiación de TC durante la infancia. Estos resultados pueden estar sujetos a factores de confusión, causalidad inversa o clasificación errónea de la exposición. El objetivo de este estudio fue comprender mejor los efectos cancerígenos de la exposición a las TC durante la infancia. Para eso, analizamos el riesgo de cáncer y las tendencias temporales del uso de las TC en un estudio de cohortes a gran escala en Suecia. Realizamos Una revisión sistemática de la literatura sobre los posibles efectos modificadores de los factores predisponentes del cáncer (FPC). Finalmente planificamos y realizamos un estudio de casos y controles anidado para abordar los posibles sesgos en los estudios de cohortes. En el estudio de la población sueca se observó un mayor riesgo de padecer cáncer y neoplasias hematológicas comparado con la población general. Sin embargo, se observó que la frecuencia de las TC disminuía con el tiempo. Se encontraron pruebas limitadas de que los FPC modifican el riesgo de cáncer inducido por la radiación. El estudio de casos y controles anidado sugiere que el riesgo de neoplasias hematológicas en los estudios de cohortes puede verse afectado por las dosis omitidas de otras pruebas radiológicas. Estos resultados se suman al conjunto de evidencia relativa a los TC y el cáncer y subrayan la necesidad de justificar estrictamente los TC pediátricos.Programa de doctorat en Biomedicin
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
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
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
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