1,721,022 research outputs found
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
HFE mutation and physical performance
No full textL’amélioration de la performance physique suscite l’intérêt du monde sportif comme du monde médical. La performance est multifactorielle. Elle est soumise à un facteur incontournable : le transport, la disponibilité et l’utilisation de l’oxygène. Mais elle relève aussi de l’interaction de facteurs environnementaux et génétiques. Certaines mutations confèrent un avantage sélectif en participant au développement de caractéristiques physiques pouvant conduire à une sélection des meilleurs potentiels. Si la mutation du gène HFE (High-Fe) dans sa forme homozygote induit une hémochromatose héréditaire (HH) caractérisée par une surcharge en fer et l’apparition de certaines pathologies avec l’âge comme la cardiomyopathie, 80 % des athlètes présentent une mutation dans ce gène. Le fer est impliqué dans de nombreuses réactions métaboliques et physiologiques telles l’érythropoïèse, le transport et l’utilisation de l’oxygène. Nous avons étudié les effets de la mutation du gène HFE chez des souris sédentaires, entraînées et au cours du vieillissement. Dans une première étude, nous nous sommes intéressés à l’évaluation des différents paramètres physiques et physiologiques des souris sédentaires mutées hétérozygotes (HT) ou homozygotes (KO) pour le gène HFE. Nous avons montré que les souris HT ont une meilleure performance physique que le groupe contrôle et le groupe KO. Dans une deuxième étude, nous avons évalué les propriétés contractiles des muscles et exploré le métabolisme et les caractéristiques musculaires de notre modèle. Nous avons pu montrer que la mutation HFE n’a aucune influence sur les propriétés contractiles ni sur le potentiel oxydatif des muscles. Cependant, l’analyse immunohistochimique des muscles montre une corrélation entre la consommation d’oxygène et le type de chaîne lourde de la myosine chez les souris KO. Dans une troisième étude, nous avons mis en évidence que la performance reste significative plus élevé chez les souris HT après un entraînement physique individualisé et adapté de 3 mois sur un tapis roulant. Enfin, afin de comprendre l’influence de la mutation sur la performance cardiaque, dans une quatrième étude nous avons effectué un suivi longitudinal par échocardiographie. Nous avons observé une diminution de la performance cardiaque avec l’âge et d’une façon plus importante chez les souris KO ; cette diminution a été contrecarrée par l’entraînement. En conclusion, une charge en fer optimale comme dans le cas des hétérozygotes pour le gène HFE pourrait être bénéfique pour la performance physique.Improving physical performance is attracting interest from both the sporting and medical world. Performance is multi-factorial. It is subject to an unavoidable factor: the transport, availability and use of oxygen. But it also comes from the interaction of environmental and genetic factors. Some mutations confer a selective advantage by participating in the development of physical characteristics that can lead to a selection of the best potentials. If the mutation of the HFE gene (High-Fe) in its homozygous form induces an hereditary hemochromatosis (HH) characterized by an iron overload and the appearance of certain pathologies with age such as cardiomyopathy, 80% of the athletes present a mutation in this gene. Iron is involved in many metabolic and physiological reactions such as erythropoiesis, transport and the use of oxygen. We studied the effects of the mutation of HFE gene in sedentary, entrained mice and during aging. In a first study, we were interested in evaluating the different physical and physiological parameters of sedentary mice heterozygous (HT) or homozygous (KO) mutated for HFE gene. We have shown that HT mice have better physical performance than control group and KO group. In a second study, we assessed the contractile properties of muscles and explored the metabolism and muscle characteristics of our model. We were able to show that HFE mutation has no influence on the contractile properties of the muscles or the oxidative potential of the muscles. However, immunohistochemical analysis of muscles shows a correlation between oxygen consumption and the type of myosin heavy chain in KO mice. In a third study, we demonstrated that the performance remains higher in HT mice after an individualized and adapted physical training of 3 months on a treadmill. Finally, in order to understand the influence of the mutation on cardiac performance, in a fourth study we performed a longitudinal follow-up by echocardiography. We observed a decrease in cardiac performance with age and more importantly in KO mice; this decrease was thwarted by the training. In conclusion, an optimal iron charge as in the case of heterozygous for HFE gene could be beneficial for physical performance
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
Gut-derived serotonin : an essential actor in iron homeostasis's regulation
No full textLe fer est un oligo-élément essentiel à la vie ; pourtant, une carence ou une surcharge en fer peut être néfaste. De ce fait plusieurs régulateurs, situés à différents niveaux sont essentiels pour contrôler son homéostasie. L’hepcidine est synthétisée par l’organe principal de stockage, le foie et est un régulateur central de cette homéostasie. Au niveau du duodénum, la régulation de l’absorption du fer est finement modulée par de nombreux signaux dont l’hypoxie ou le bloc muqueux. Enfin, plus récemment a été mis en évidence l’érythroferrone, un facteur produit par les progéniteurs érythroïdes de la moelle osseuse, principal site d’utilisation du fer lors de l’érythropoïèse, malgré ces régulateurs, de nombreux troubles de l’homéostasie du fer restent inexpliqués. La génération d'un modèle murin invalidé pour le gène Tph1 (codant pour l'enzyme tryptophane hydroxylase 1) a révélé une dysrégulation du fer. La protéine Tph1 est l'enzyme limitante de la synthèse de la sérotonine (5-HT) périphérique. La 5-HT périphérique représente 95% de la sérotonine de l'organisme et est synthétisée par les cellules entérochromaffines du tractus intestinal. Les souris dépourvues de sérotonine d’origine intestinale (Tph1-/-) présentent une anémie sidéroblastique ainsi qu'une ferritine sérique élevée malgré une hepcidine très élevée. Ce phénotype suggère alors une dysrégulation de l'homéostasie du fer chez la souris dépourvue en 5-HT périphérique. Nous avons donc voulu déterminer les rôles potentiels de la 5-HT dans la régulation de l’hepcidine (régulateur systémique) mais aussi dans l'absorption du fer (régulateur entérocytaire). En effet, le fer est absorbé par les entérocytes du duodénum qui font partie du même tissu que les cellules entérochromaffines. Il a alors été montré dans un premier temps que sous hypoxie, la 5-HT intestinale réprime l'expression de Hamp1, gène codant pour l'hepcidine. La 5-HT agit via son récepteur spécifique 5-HT2B des hépatocytes. En conclusion, la 5-HT d'origine intestinale intervient dans la régulation de l'homéostasie du fer au niveau systémique (hépatocyte) et à un niveau local (entérocyte). La compréhension de ces différents rôles de la 5-HT dans l'homéostasie du fer pourrait ouvrir de nouvelles voies thérapeutiques dans des pathologies liées à une carence ou une surcharge en fer.Iron is an essential nutrient to life, yet an iron deficiency or overload can be harmful. For this reason, several regulators, located at different levels, are essential to control its homeostasis. Hepcidin is synthesized by the main storage organ, the liver, and is a central regulator of this homeostasis. In the duodenum, the regulation of iron absorption is finely modulated by numerous signals including hypoxia or mucosal block. Finally, more recently, erythroferrone, a signal produced by the erythroid progenitors of the bone marrow, the main site of iron use during erythropoiesis, has been highlighted. Despite these regulators, many disorders of iron homeostasis remain unexplained. The generation of a mouse model invalidated for Tph1 gene (encoding the enzyme tryptophan hydroxylase 1) revealed iron dysregulation. The Tph1 protein is the limiting enzyme for peripheral serotonin (5-HT) synthesis. Peripheral 5-HT represents 95% of the body's serotonin and is synthesized by enterochromaffin cells in the intestinal tract. Mice lacking intestinal serotonin (Tph1-/-) have sideroblastic anemia and high serum ferritin despite very high hepcidin. This phenotype then suggests a dysregulation of iron homeostasis in mice devoid of peripheral 5-HT. We therefore wanted to determine the potential roles of 5-HT in the regulation of hepcidin (systemic regulator) but also in iron absorption (enterocyte regulator). Indeed, iron is absorbed by enterocytes of the duodenum which are part of the same tissue as enterochromaffin cells. Along that line, we showed initially that under hypoxia, intestinal 5-HT represses the expression of Hamp1, the gene coding for hepcidin. 5-HT acts via its specific hepatocyte 5-HT2B receptor. At the local level, we showed that intracellular 5-HT regulates iron absorption in the enterocyte. In conclusion, intestinal 5-HT is involved in the regulation of iron homeostasis at a systemic level (hepatocyte) and at a local level (enterocyte). Understanding these different roles of 5-HT in iron homeostasis could open new therapeutic avenues in pathologies related to iron deficiency or overload
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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