1,721,473 research outputs found
Xvelo1 uses a novel 75-nucleotide signal sequence that drives vegetal localization along the late pathway in Xenopus oocytes
No full textAbstractVegetally localized RNAs in Xenopus laevis oocytes are involved in the patterning of the early embryo as well as in cell fate specification. Here we report on the isolation and characterization of a novel, vegetally localized RNA in Xenopus oocytes termed Xvelo1. It encodes a protein of unknown biological function and it represents an antisense RNA for XPc1 over a length of more than 1.8 kb. Xvelo1 exhibits a localization pattern reminiscent of the late pathway RNAs Vg1 and VegT; it contains RNA localization elements (LE) which do not match with the consensus structural features as deduced from Vg1 and VegT LEs. Nevertheless, the protein binding pattern as observed for Xvelo1-LE in UV cross-linking experiments and coimmunoprecipitation assays is largely overlapping with the one obtained for Vg1-LE. These observations suggest that the structural features recognized by the protein machinery that drives localization of maternal mRNAs along the late pathway in Xenopus oocytes must be redefined
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
oocytes
No full textRNAs that localize to the vegetal cortex of Xenopus oocytes are involved in early embryonic patterning and cell fate specification. Two mechanistically distinct pathways lead to RNA enrichment at the vegetal cortex: the early and the late. While several candidate proteins that seem to operate in the late localization pathway have been identified, proteins involved in the early pathway remain to be identified. In this study, we report on the isolation of a novel vegetally localized RNA in Xenopus oocytes that makes use of the early pathway and encodes a protein with a conserved but functionally uncharacterized NIF-motif. The localization signal of XNIF was mapped to a 300-nucleotide region in the 5'-UTR, which is able to mediate both accumulation to the mitochondrial cloud in stage I oocytes, as well as vegetal transport in later stage oocytes. The XNIF-LE contains 16 copies of the previously defined CAC-containing signal motifs for RNA localization. A critical number of such repeats seems to be required for accumulation in the mitochondrial cloud along the early pathway, but additional repeats seem to be required for localization along the late pathway. Cross-linking experiments identify two novel proteins of 62 and 64 kDa that interact with the XNIF-LE but not with the Vg1-LE that operates in the late pathway. Conversely, at least two of the previously identified VgRBPs, Vg1RBP1 and Prrp, also bind to the XNIF-LE. Thus, overlapping, but not identical, protein machineries mediate vegetal RNA localization along early and late pathways in Xenopus oocytes
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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