1,720,975 research outputs found

    ESCRT-III assembly and cytokinetic abscission are induced by tension release in the intercellular bridge

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    The last step of cell division, cytokinesis, produces two daughter cells that remain connected by an intercellular bridge. This state often represents the longest stage of the division process. Severing the bridge (abscission) requires a well-described series of molecular events, but the trigger for abscission remains unknown. We found that pulling forces exerted by daughter cells on the intercellular bridge appear to regulate abscission. Counterintuitively, these forces prolonged connection, whereas a release of tension induced abscission. Tension release triggered the assembly of ESCRT-III (endosomal sorting complex required for transport-III), which was followed by membrane fission. This mechanism may allow daughter cells to remain connected until they have settled in their final locations, a process potentially important for tissue organization and morphogenesis

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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

    Septate junctions remodeling and abscission during cytokinesis of Drosophila epithelial cells

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    Au cours de la cytocinèse épithéliale, la nouvelle interface formée entre les cellules filles est le lieu du remodelage des barrières mécanique et de perméabilité, ainsi que l’initiation de la communication cellulaire. Pour comprendre comment ces fonctions sont maintenues tout au long de la division jusqu’à l’abscission, nous utilisons l’épithélium du thorax dorsal de Drosophila au stade pupal. Cet épithélium est composé de cellules épidermiques à division symétrique ; et de précurseurs des organes sensoriels (SOP) à division asymétrique, qui génèrent deux cellules filles (pIIb/pIIa) dont l’identité dépend de l’activation différentielle de la voie de signalisation Notch. Dans ces cellules épithéliales, le midbody se forme suite à la constriction asymétrique de l’anneau de cytocinèse, puis se déplace basalement dans les jonctions septées (SJ) grâce à la maturation apico-basale des nouvelles SJ. Les expériences de photoconversion montrent que l’isolation cytoplasmique se produit 60-70 min après l’anaphase des SOP, un moment qui coïncide avec le recrutement de Shrub/ESCRT-III ; un régulateur connu de l’abscission. La perturbation de Shrub indique que la protéiine contrôle le moment de l’isolation cytoplasmique dans pIIb/pIIa, et affecte l’intégrité des SJ. Aussi, en parallèle, nous étudions si les composants de SJ peuvent réguler l’abscission dans les filles des SOP. Ces travaux devraient donc permettre de mieux comprendre le lien entre le remodelage des SJ, l’abscission et l’acquisition de l’identité cellulaire.During epithelial cytokinesis, the new daughter cell interface formed is the place of mechanical and permeability barriers remodeling, as well as the initiation of cell-cell communication. To decipher how barrier functions are maintained throughout division until abscission, we use the Drosophila dorsal thorax epithelium at pupal stage. This epithelium is composed of epidermal cells, which divide symmetrically; and sensory organ precursors (SOPs) that divide asymmetrically to generate two daughter cells (pIIb/pIIa) whose identities rely on differential activation of the Notch signaling. In those epithelial cells, the midbody assembles following the asymmetric constriction of cytokinetic ring, and then moves basally within septate junctions (SJs) thanks to the apico-basal maturation of new SJs. Photoconversion assays reveal that cytoplasmic isolation occurs 60-70 min after the SOP anaphase onset, a timing that coincides with the recruitment of Shrub/ESCRT-III; a known regulator of the abscission. Disturbance of Shrb indicates that the protein controls the timing of cytoplasmic isolation in pIIb/pIIa; and that it affects the SJ integrity. In parallel, we are investigating whether SJ components can regulate the abscission of SOP daughter cells. Therefore, this work should highlight the interplay between SJ remodeling, abscission and cell fate acquisition
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