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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
Architecture développementale de la lymphopoïèse humaine
No full textSelon le modèle standard de l'hématopoïèse, la différenciation des cellules souches hématopoïétiques est un processus graduel de type arborescent. La première séparation a lieu au niveau de cellules multipotentes qui se scindent en progéniteurs lymphoïdes et myéloïdes communs. Bien que l'architecture de l'hématopoïèse humaine reste encore mal connue, de nombreux travaux suggèrent qu'elle ne suit pas le modèle standard. À ce jour encore, la question de l'existence d'un équivalent humain du CLP murin, n'a pas été tranchée. L'étude de l'hématopoïèse humaine soulève des problèmes méthodologiques. Ceci est lié au difficile accès au; prélèvements de moelle primaire et les études sur le sang placentaire ne reflètent pas complétement le développement médullaire. Dans ce travail, nous avons utilisé un modèle in vivo d'hématopoïèse foetale humaine chez la souris NSG par xénogreffe de progéniteurs du sang placentaire. La caractérisation faite sur les populations générées dans la moelle osseuse de souris a révélé que ce modèle reproduit l'hématopoïèse foetale humaine. Nous montrons que la lymphopoïèse foetale humaine présente une organisation originale caractérisée par une duplication des axes développementaux. Nos travaux mettent en évidence l'émergence indépendante de deux type de progéniteurs lymphoïdes à partir d'un intermédiaire multipotent: une population ancestrale CD127+générant principalement des lymphocytes B folliculaires, ainsi que des cellules ILC3 ; une population CD127- générant des lymphocytes T, des lymphocytes B de la zone marginale, et des cellules NK/ILC1. Ces résultats montrent que l'hématopoïèse humaine ne suit pas le modèle standard établi chez la souris.The standard model of hematopoiesis proposes that hematopoietic differentiation is a stepwise bifurcation process. The first separation downstream of hematopoietic stem cells will segregate mutipotent progenitors into common lymphoid and myeloid progenitors. In human many evidences support the idea that human hematopoietic organization doesn't follow the classical model, but the question was not concluded and need for further investigation. Due to limited access to primary bone marrow samples and lack of appropriate in vivo model human studies face many difficulties. In this work, we used a xenogeneic model of human fetal hematopoiesis in immune-deficient mice to dissect the early stages of lymphoid development. This model relies on the injection of UCB CD34+ cells into NSG mice. Flow cytometry analysis and gene expression profiling of humanized mice BM populations revealed that this model faithfully reproduces human fetal hematopoiesis. Combining in vitro differentiation assays to molecular studies and genetic approaches, we show that fetal human lymphopoiesis displays a dual organization, split into an ancestral CD127+ CLP-like population devoid o myeloid potential that differentiate preferentially into follicular B cells and ILC3s, and into a previously undescribed CD127- population mainly dedicated to the generation of T, marginal zone B, NK, and ILC1s We also provide evidence that Early Lymphoid Progenitors emerge independently from multipotent developmental intermediates referred to as lympho-mono'dendritic progenitors. These results confirm that human hematopoiesis doesn't follow the standard model of hematopoietic differentiation established in the mouse
Dynamics of human lymphopoiesis during development and aging : the origins of adaptive immunity
No full textLa recherche de changements liés à l'ontogénie a longtemps été entravée par le manque de définition immunophénotypique et fonctionnelle unifiée des progéniteurs lymphoïdes humains. L'observation majeur dans le domaine a émergé il y a trois décennies avec l'identification d'une sous-population de CD45RA+CD10+ à restrieinte lymphoïde dans la Moelle adulte (Galy et al., 1995). Des études ultérieures réalisées sur les HPC CD45RA+CD10+ du sang de cordon ombilical ont confirmé leur restriction lymphoïde mais ont soulevé des doutes quant à leur statut de développement/différenciation et leur fonction biologique, depuis, selon les auteurs, cette population était alors qualifiée de progéniteurs « multilymphoïdes » (MLP) (Doulatov et al., 2010) ou de progéniteurs postnatals colonisant le thymus (Lavaert et al., 2020 ; Six et al., 2007). La situation était encore compliquée par le fait qu'en plus, des ETP CD7+ (Haddad et al., 2004 ; Haddad et al., 2006), une autre population de MLP CD38loCD7+ (Hao et al., 2001 ; Hoebeke et al., 2007) a été décrite dans le sang néonatal, ainsi que par l'observation que les sous-populations lymphoïdes CD7+ et CD10+ suivent une cinétique opposée à travers l'ontogénie, ce qui suggère qu'ils pourraient correspondre respectivement aux sous-ensembles foetaux et postnatals. Pour pallier les insuffisances des études sur les progéniteurs lymphoïdes circulants néonatals qui ne permettent pas une délimitation précise des trajectoires développementales sous-jacentes aux relations de lignées, notre groupe a développé une approche originale de modélisation de l'hématopoïèse foetale humaine chez des souris immunodéficientes (Alhaj Hussen et al. et al., 2012). Cela a conduit à découvrir que la lymphopoïèse humaine présente une architecture bipartite provenant de populations distinctes de progéniteurs lymphoïdes précoces (ELP) CD127- ou CD127+, chacun subissant une diversification en aval en précurseurs spécifiés par la lignée CD7+ T-NK/ILC- ou CD7-B. Dans mon travail de recherche doctorale, nous avons tenté de réconcilier le modèle d'organisation lymphoïde à deux familles avec le paradigme CD7 versus CD10 basé sur l'ontogenèse. Sur la base d'une analyse combinée des changements dépendants de l'âge, de l'architecture lymphoïde et du potentiel chez les donneurs entre 13 semaines de développement et de 87 ans, nous démontrons que malgré la préservation de l'architecture bipartite canonique, la transition fœtale à postnatale est associée à un biais majeur dans la lymphopoïèse vers les ELP CD127+ et la production de cellules B, et que ces changements dans les schémas de production de lymphocytes sont associés à un changement immunophénotypique de CD7 à CD10 des progéniteurs lymphoïdes postnatals. Plus important encore, nous apportons la preuve que cette transition est contrôlée au niveau des HSC par une horloge de développement non décrite auparavant. Dans la mesure où ils démontrent que le déclin du potentiel des cellules T est programmé au niveau du développement, nos résultats ont des implications importantes pour comprendre l'établissement et le maintien de l'immunité adaptative chez l'homme.The search for ontogeny-related changes has long been hampered by the lack of unified immunophenotypic and functional definition of human lymphoid progenitors. The prevailing view in the field has emerged three decades ago with the identification of a minor subset of lymphoid-restricted CD45RA+CD10+ HPCs in the adult BM (Galy et al., 1995). Subsequent studies performed on the CD45RA+CD10+ HPCs from the umbilical cord blood confirmed their lymphoid restriction but raised doubts as to their development/differentiation status and biological function since, depending on the authors, this population was then referred to as "multilymphoid" progenitors (MLPs) (Doulatov et al., 2010) or as postnatal thymus-seeding progenitors (Lavaert et al., 2020; Six et al., 2007). The situation is further complicated by the fact that, beside previously described CD7+ ETPs (Haddad et al., 2004; Haddad et al., 2006), another population of CD38loCD7+ MLPs (Hao et al., 2001; Hoebeke et al., 2007) has been described in the neonatal blood, as well as by the observation that the CD7+ and CD10+ lymphoid subsets follow opposite kinetics across ontogeny which suggests that they might correspond respectively to fetal and postnatal subsets. To overcome the shortcomings of studies on neonatal circulating lymphoid progenitors that do not allow a precise delineation of the underlying developmental trajectories lineage relationships our group has developed an original modeling approach of human fetal hematopoiesis in immunodeficient mice (Alhaj Hussen et al., 2017; Parietti et al., 2012). This led to finding human lymphopoiesis displays a bipartite architecture stemming from distinct populations of CD127- or CD127+ early lymphoid progenitors (ELPs) each undergoing downstream diversification into either CD7+ T-NK/ILC- or CD7- B lineage-specified precursors. In my doctoral research work, we attempted to reconcile the two-family model lymphoid organization with the ontogeny-based CD7 versus CD10 paradigm. Based on combined analysis of age-dependent changes in lymphoid architecture and potential in donors between 13 PCW and the age of 87 years, we demonstrate that despite preservation of the canonical bipartite architecture, the fetal to postnatal transition is associated with a major bias in lymphopoiesis toward the CD127+ ELPs and subsequent production of B cells, and that these changes in lymphocyte production patterns are associated with a CD7 to CD10 immunophenotypic shift of postnatal lymphoid progenitors. Most importantly, we provide evidence that this transition is controlled at the level of HSCs by a previously undescribed development clock. Inasmuch as they demonstrate the decline in T cell potential is developmentally programmed, our results have important implications for understanding establishment and maintenance of adaptative immunity in humans
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
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