1,721,009 research outputs found
Méthodes statistiques génétiques pour l’étude des phénotypes de maladies infectieuses (paludisme) à partir de données de suivi longitudinal obtenues dans des cohortes familiales
No full textLong term longitudinal surveys have the advantage to enable several sampling of the studied phenomena and then, with the repeated measures obtained, find a confirmed tendency. However, these long term surveys generate large epidemiological datasets including more sources of noise than normal datasets (e.g. one single measure per observation unit) and potential correlation in the measured values. Here, we studied data from a long-term epidemiological and genetic survey of malaria disease in two family-based cohorts in Senegal, followed for 19 years (1990–2008) in Dielmo and for 16 years (1993–2008) in Ndiop. The main objectives of this work were to take into account familial relationships, repeated measures as well as effect of covariates to measure both environmental and host genetic (heritability) impacts on the outcome of infection with the malaria parasite Plasmodium falciparum, and then use findings from such analyses for linkage and association studies. The outcome of interest was the occurrence of a P. falciparum malaria attack during each trimester (PFA). The two villages were studied independently; epidemiological analyses, estimation of heritability and individual effects were then performed in each village separately. Linkage and association analyses used family-based methods (based on the original Transmission Disequilibrium Test) known to be immune from population stratification problems. Then to increase sample size for linkage and association analyses, data from the two villages were used together.Les études longitudinales sur une longue période permettent d’échantillonner plusieurs fois le phénomène étudié et ainsi, avec des mesures répétées, dégager une tendance confirmée. Mais, dès lors, elles produisent de très larges bases de données épidémiologiques accompagnées de plus de sources de bruit par rapport aux études à observation unique ; et souvent, contiennent de la corrélation dans les mesures. Ici, nous avons présenté à travers cette thèse une étude de long terme des facteurs épidémiologiques et génétiques du paludisme menée dans deux cohortes familiales du Sénégal, l’une dans le village de Dielmo suivi pendant 19 années consécutives (1990 – 2008) et l’autre dans le village de Ndiop suivi pendant 16 années consécutives (1993 – 2008). L’objectif de ce travail de thèse a été de développer des méthodes d’analyse statistique pour identifier des gênes de susceptibilité / résistance au paludisme prenant en compte les relations familiales, les mesures répétées et des potentielles interactions génotypes – environnement dans l’évaluation des phénotypes. Par la suite, de tels phénotypes corrigés des facteurs identifiés comme potentielles sources de confusion et/ou de bruit ont été alors utilisés pour les tests de liaison et d’association génétique. Le phénotype principal étudié chez chaque volontaire a été la survenue ou non d’accès palustre, attribué à une infection au parasite Plasmodium falciparum, durant chaque trimestre de présence (PFA). Les études ont été menées de manière indépendante dans chacun des deux villages, de même que les analyses descriptives, l’estimation de la contribution génétique humaine et des effets individuels. Les tests de liaison et d’association génétique ont été réalisés par des méthodes familiales basées sur l’analyse de la transmission d’allèles des parents aux enfants (Transmission Disequilibrium Test). Ces méthodes sont connues pour être robustes par rapport au problème de la stratification de population et donc nous permettent d’augmenter la taille de notre échantillon dans les études de liaison et d’association génétique en analysant les deux villages en même temps
Development and deployment of a rapid recombinase polymerase amplification Ebola virus detection assay in Guinea in 2015
No full textIn the absence of a vaccine or specific treatments for Ebola virus disease (EVD), early identification of cases is crucial for the control of EVD epidemics. We evaluated a new extraction kit (SpeedXtract (SE), Qiagen) on sera and swabs in combination with an improved diagnostic reverse transcription recombinase polymerase amplification assay for the detection of Ebola virus (EBOV-RT-RPA). The performance of combined extraction and detection was best for swabs. Sensitivity and specificity of the combined SE and EBOV-RT-RPA were tested in a mobile laboratory consisting of a mobile glovebox and a Diagnostics-in-a-Suitcase powered by a battery and solar panel, deployed to Matoto Conakry, Guinea as part of the reinforced surveillance strategy in April 2015 to reach the goal of zero cases. The EBOV-RT-RPA was evaluated in comparison to two real-time PCR assays. Of 928 post-mortem swabs, 120 tested positive, and the combined SE and EBOV-RT-RPA yielded a sensitivity and specificity of 100% in reference to one real-time RT-PCR assay. Another widely used real-time RT-PCR was much less sensitive than expected. Results were provided very fast within 30 to 60 min, and the field deployment of the mobile laboratory helped improve burial management and community engagement
Mobile deployment of recombinase polymerase amplification based rapid diagnostics for Ebola virus disease in Guinea in 2015
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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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