1,720,974 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
Immature B cells from human and mouse bone marrow can change their surface light chain expression
No full textThe capacity of bone marrow-derived surface immunoglobulin-positive (sIg(+)) human and mouse immature B cells, generated either in vitro or in vivo, to change their light (L) chain expression, has been assayed by the number of cells which change in vitro from one type of L chain to the other type, or to no sig at all. Immature sIg(+) B cells were generated in vitro from sig precursor cells from human or mouse bone marrow. The immature sIg(+) cells expressed RAG-1, Human sIg(+) cells expressed kappa and lambda L chains in ratios between 1:1 and 3:1, whereas in mouse cells, this ratio ranged from 10:1 to 20:1. Upon reculture of the human and mouse kappa(+) sIg(+) cells, about half of them remained kappa(+), a quarter became lambda(+), and another quarter became sIg(-). Between 1 and 3% expressed both kappa and lambda chains. Of the human lambda(+) cells, about two-thirds remained lambda(+), only 1 to 2% became kappa(+), while the other third became sIg(-). Again, between 1 and 3% expressed both kappa, and lambda L chains. These results indicate that expression of sIgM in the B cell membrane does not terminate L chain gene rearrangement, and that some order exists in kappa versus lambda gene rearrangements. Hence, human and mouse kappa(+) immature B cells can become lambda(+), but very few of the lambda(+) cells can become kappa(+), and both can become sIg(-). Further, human CD10(+)/sIg(+) kappa(+) and lambda(+) cells and mouse B220(low)/sIg(low) kappa(+) cells enriched from bone marrow, i.e. immature B cells differentiated in vivo, changed their Ig phenotype upon in vitro culture, but in lower frequencies. By contrast, human and mouse mature B cells did not change their L chain or Ig phenotype. Hence, at least a part of the sIg(+) immature B cells in bone marrow retain the capacity to change their L chain and Ig phenotype, and this capacity is lost when they become mature, peripheral B cells
Positive and negative selection events during B lymphopoiesis
No full textEarly in B-cell development, large numbers of cells have to be generated, each of which expresses only one type of B-cell receptor (i.e. Ig) on its surface. This is achieved by the surface expression of a pre-B cell receptor containing a mu heavy chain/surrogate light chain which differentially provides signals for two responses of precursor B cells at this stage of development. On the one hand, it signals inhibition of further rearrangements of variable heavy chain to diverse-joining heavy chain loci to achieve allelic exclusion at the heavy-chain locus. On the other hand, it signals proliferative expansion by factors between 20 and 100. Later in B-cell development, tolerance to autoantigens must be established and maintained. Tolerance is achieved by developmental arrest and induction of secondary light-chain gene rearrangements in those IgM+ immature B cells that are reactive to autoantigens presented in the primary B-cell generating organs. Even later in development, when mature surface (s)IgM+/sIgD+ B cells encounter autoantigens presented to them in the periphery, either deletion or anergy of the autoantigen-reactive cells occurs. Anergic cells have a sig-dependent, sIg-proximal defect in signaling and are short-lived. Anergy can be broken in vitro by polyclonal activation via ligation of CD40 in the presence of IL-4. A small part of the remaining immature B cells not reactive to autoantigens are selected to become mature, antigen-reactive sIgM+/sIgD+ B cells. Molecules which might guide such positive selection of B cells still remain to be identified
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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