1,720,963 research outputs found
An arrow for wingless to take-off
No full textThe Wnt family of secreted glycoproteins is involved in the regulation of diverse developmental processes. The classical Wnt/beta -catenin pathway has been thoroughly investigated resulting in the identification of a plethora of components involved in the activation of beta -catenin target genes. Moreover, two additional Wnt-triggered pathways have been identified. These various signalling cascades require at least one component that confers signalling specificity. This function is fulfilled at least in part by the Wnt receptor Frizzled. The recent identification of a potential Frizzled co-receptor, an LDL-receptor-related-protein (LRP),((1-3)) sheds more light on Wnt-signal transduction specificity and promises more exciting revelations. BioEssays 23:207-210, 2001. (C) 2001 John Wiley & Sons, Inc
Cardiac specific expression of Xenopus Popeye-1
No full textPopeye genes code for putative transmembrane proteins that are predominantly expressed in heart and skeletal muscle. Here we report on the isolation and expression of a previously unknown Xenopus member of this family, Xenopus Popeye-1 (Xpop-1). Xpop-1 is 60-65% identical to other vertebrate Pop-1 genes at the protein level. Whole-mount in situ hybridization studies revealed a highly specific expression of Xpop-1 whose transcripts are restricted to the embryonic heart and become enriched in the forming ventricle. Interestingly, unlike other known vertebrate Popeye genes, Xpop-1 is exclusively expressed in cardiac tissue and absent from skeletal muscle. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved
Wnt-11 activation of a non-canonical Wnt signalling pathway is required for cardiogenesis
No full textFormation of the vertebrate heart requires a complex interplay of several temporally regulated signalling cascades(1). In Xenopus laevis, cardiac specification occurs during gastrulation and requires signals from the dorsal lip and underlying endoderm(2). Among known Xenopus Wnt genes, only Wnt-11 shows a spatiotemporal pattern of expression that correlates with cardiac specification, which indicates that Wnt-11 may be involved in heart development(3,4). Here we show, through loss- and gain-of-function experiments, that XWnt-11 is required for heart formation in Xenopus embryos and is sufficient to induce a contractile phenotype in embryonic explants. Treating the mouse embryonic carcinoma stem cell line P19 with murine Wnt-11 conditioned medium triggers cardiogenesis, which indicates that the function of Wnt-11 in heart development has been conserved in higher vertebrates. XWnt-11 mediates this effect by non-canonical Wnt signalling, which is independent of beta-catenin and involves protein kinase C and Jun amino-terminal kinase. Our results indicate that the cardiac developmental program requires non-canonical Wnt signal transduction
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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