1,720,956 research outputs found
Effects of sequence selective drugs on the gel mobility of a bent DNA fragment
No full textThe effects of various drugs on the structure of a bent DNA fragment have been investigated by studying DNA mobility in polyacrylamide gels. This DNA fragment has an anomalously slow rate of migration on account of its phased runs of adenines. Nogalamycin and echinomycin increase the gel mobility of kinetoplast DNA suggesting that the bending has been removed. Mithramycin, actinomycin, distamycin and ethidium have either no effect or cause a further reduction in mobility. These results are compared with other, non-bent DNA species which always show a decrease in gel mobility in the presence of DNA binding drugs.</p
Interaction of mithramycin with DNA fragments complexed with nucleosome core particles: Comparison with Distamycin and Echinomycin
No full textWe have studied the sequence-specific interaction of mithramycin with nucleosome core particles which have been reconstituted with various DNA fragments. Mithramycin binds to these DNAs without disrupting the integrity of the nucleosome and produces clear DNase I footprints centered around GC-rich regions. In some instances, the footprints produced on free DNA are resolved into two or more smaller sites when the DNA is complexed with the nucleosome core. In a few cases, novel footprints are produced in sequences which did not bind the drug in free DNA samples. The results are explained by suggesting mithramycin binds to GC-rich regions in which the minor groove faces away from the protein core, and which possess a wider than normal narrow groove on account of their location. Hydroxyl radical footprinting and diethyl pyrocarbonate modification confirm that mithramycin does not affect the rotational positioning of the nucleosome-bound DNA. Although distamycin and echinomycin induce novel DNase I digestion products in nucleosomal DNA which are consistent with the proposed change in DNA positioning [Low, C. M. L., Drew, H. R., & Waring, M. J. (1986) Nucleic Acids Res. 14, 6785–6801], hydroxyl radical footprinting and diethyl pyrocarbonate modification suggest these ligands do not change the rotational positioning of the DNA on the nucleosome cores.</p
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
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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