1,721,002 research outputs found

    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

    Endoreduplication induced in cultured Chinese hamster cells by different anti-topoisomerase II chemicals. Evidence for the essential contribution of the enzyme to chromosome segregation.

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    With the ultimate purpose of testing the hypothesis that, as shown in yeast mutants, any malfunction of DNA topoisomerase II might result in aberrant mitosis due to defective chromosome segregation, we have chosen three chemicals of different nature, recently reported to catalytically inhibit the enzyme. The endpoint selected to assess any negative effect on the ability of topoisomerase II to properly carry out decatenation of fully replicated chromosomes in the G2/M phase of the cell cycle was the presence of metaphases showing diplochromosomes as a result of endoreduplication, i.e. two successive rounds of DNA replication without intervening mitosis. The anti-topoisomerase drugs selected were the anthracycline antibiotic and antineoplastic agent aclarubicin, the respiratory venom sodium azide, and 9-aminoacridine, a chemical compound with planar topology capable of intercalation between DNA bases. Our results show that the three chemicals tested are able to induce endoreduplication to different degrees. These observations seem to lend support to the proposal that topoisomerase II plays a central role in chromosome segregation in mammalian cell

    Cisplatin-induced endoreduplication in CHO cells: DNA damage and inhibition of topoisomerase II.

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    It has been proposed that polyploid cells that arise during a variety of pathological conditions and as a result of exposure to genotoxicants, typically in the liver, become aneuploid through genetic instability. Aneuploidy contributes to, or even drives, tumour development. We have assessed the capacity of the drug cisplatin, one of the most commonly used compounds for the treatment of malignancies, to induce endoreduplication, a particular type of polyploidy, in cultured Chinese hamster AA8 cells. Taking into account that any interference with DNA topoisomerase II (topo II) function leads to endoreduplication, we have found that treatment of the cells with this platinum compound results in a dose-dependent inhibition of the catalytic activity of the enzyme. These observations are discussed on the basis of a possible dual action of cisplatin leading to a combined negative effect on normal segregation of chromosomes. On the one hand, through the drug capacity to efficiently inhibiting the catalytic activity of topo II itself and, on the other hand, as a consequence of changes in DNA such as base modifications and cross-links that result from cisplatin treatment, likely leading to a lack of recognition/binding of DNA by the enzyme. These observations support a model in which the involvement of topo II in different pathways leading to induced endoreduplication has been proposed, and seem to bear significance as to the possible origin of the development of secondary tumours as a result of cisplatin treatment of primary malignancies
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