1,721,040 research outputs found
Smear Microscopy Complements Xpert MTB/RIF When Considering Nontuberculous Mycobacterial Infections
No full text
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
Impact of the host on the risk of emergence of bedaquiline resistance in Mycobacterium tuberculosis
No full textMon projet visait à décrire et caractériser l'émergence chez Mycobacterium tuberculosis de la résistance à la bédaquiline (BDQ). Dans une première étude, nous avons réalisé un test de fluctuation in vitro et adapté celui-ci pour la première fois in vivo dans des souris immunocompétentes et des souris immunodéprimées. Nous avons mis en évidence que l’immunodépression semblait augmenter le risque d’émergence de résistance mais cette augmentation ne serait pas due à une augmentation du taux de mutation mais à une hétérogénéité plus grande au sein de cette population avec des individus s’éloignant beaucoup des valeurs moyennes et hébergeant de grandes quantités de mutants. Dans un second travail, nous avons décrit le premier cas européen de sélection de résistance à la BDQ par mutation atpE. Enfin, nous avons réalisé une étude rétrospective de la sensibilité à la BDQ parmi toutes les souches MDR isolées en France entre 2018 et 2020. Une analyse génotypique et phénotypique a permis de mettre en évidence que des souches mutées sont classées phénotypiquement sensibles selon les critères actuels de l’OMS et que ces souches sont un mélange de souches sans augmentation de la CMI et de souches avec une minime augmentation de la CMI ne faisant pas classer la souche comme résistante. Pour conclure, nous avons montré que les travaux classiquement réalisés in vitro pour mesurer le taux de mutation ne donnent qu’une idée simplifiée de la complexité de l’émergence de la résistance in vivo. Nos travaux ont aussi montré qu’il est difficile avec les outils génotypiques et phénotypiques actuels de distinguer les souches de Mycobacterium tuberculosis sensibles des souches résistantes à la BDQ.The aim of my project was to describe and characterise the emergence of bedaquiline (BDQ) resistance in Mycobacterium tuberculosis. In a first study, we performed an in vitro fluctuation test and adapted it for the first time in vivo in immunocompetent and immunosuppressed mice. We found that immunosuppression appeared to increase the risk of resistance emergence, but this increase was not due to an increase in the mutation rate but to greater heterogeneity in this population, with individuals deviating significantly from the mean values and harbouring large numbers of mutants. In a second work, we described the first European case of selection for BDQ resistance by atpE mutation. Finally, we performed a retrospective study of BDQ susceptibility among all MDR strains isolated in France between 2018 and 2020. Genotypic and phenotypic analysis showed that mutated strains are classified as phenotypically susceptible according to the current WHO criteria and that these strains are a mixture of strains with no increase in MIC and strains with a minimal increase in MIC that do not classify the strain as resistant. In conclusion, we have shown that the work classically performed in vitro to measure mutation rate only gives a simplified idea of the complexity of the emergence of resistance in vivo. Our work has also shown that it is difficult with current genotypic and phenotypic tools to distinguish between Mycobacterium tuberculosis strains that are susceptible and those that are resistant to BDQ
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
Mycobacterium tuberculosis fluoroquinolone resistance : natural history and diagnosis of resistance
No full textLa résistance aux fluoroquinolones (FQ) est le principal facteur d'aggravation du pronostic de la tuberculose multi-résistante. Il apparait donc essentiel de mieux comprendre le développement de la résistance aux FQ afin d'améliorer les outils permettant une détection précoce de cette résistance. Nous avons (i) évalué les performances du séquençage des gènes gyrA et gyrB dans la détection de la résistance aux FQ grâce à une étude prospective menée au CNR-MyRMA ; (ii) étudié l'histoire naturelle de l'émergence de la résistance aux FQ in vivo dans un modèle murin de tuberculose et (iii) identifié de nouveaux mécanismes de résistance aux FQ par génomique comparative. Nous avons montré que la méthode des proportions, désignée comme méthode de référence, n'est pas performante pour la détection des bas niveaux de résistance aux FQ et que ni les méthodes génotypiques ni les méthodes phénotypiques, ne permettent le diagnostic de la résistance hétérogène aux FQ. Une stratégie combinée reposant sur une détection phénotypique d'une proportion anormale de bactéries résistantes et une caractérisation génotypique de ces bactéries résistantes permettrait d'améliorer la détection de cette résistance hétérogène. Nous avons identifié des pistes pour de nouveaux mécanismes de résistance aux FQ. Il pourrait s'agir de mécanismes responsables d'une résistance de bas niveau facilitant la sélection d'une résistance de haut niveau due à une mutation dans les gènes codant l'ADN gyrase dans un deuxième temps. Cependant, leur implication dans la résistance aux FQ, ainsi que notre hypothèse quant au processus de sélection, reste à démontrer.Fluoroquinolone (FQ) resistance is the main factor of worsened prognosis of multidrug resistant tuberculosis. Therefore to better understand the development of FQ resistance is essential in order to improve the tools for early detection of this resistance. We have (i) evaluated the performance of gyrA and gyrB sequencing in the detection of FQ resistance through a prospective study; (ii) studied the natural history of the emergence of FQ resistance in vivo using a murine model of tuberculosis; and (iii) identified tracks for new mechanisms of resistance to FQ by comparative genomics. We showed that the proportion method, designated as the reference method, is not effective in detecting low levels of FQ resistance and that, neither genotypic methods nor phenotypic methods, allow the diagnosis of FQ heterogeneous resistance. A combined strategy based on phenotypic detection of an abnormal proportion of resistant bacteria and genotypic characterization of these resistant bacteria would improve the detection of this heterogeneous resistance. We have identified hypotheses for new FQ resistance mechanisms. These new mechanisms could be responsible of a low-level resistance facilitating the selection of a high-level resistance due to mutations in genes encoding DNA gyrase in a second time. However, their involvement in FQ resistance and our assumption about the selection process remain to be demonstrated
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
- …
