1,720,960 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
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
Studies on the chemistry of taxol
No full textThe novel diterpenoid taxol isolated from the western yew Taxus brevifolia is one of the most important lead compounds to emerge from the search for anticancer agents from plants. It shows consistent clinical activity against ovarian cancer and may also be active against other cancers. In this study, the preparation of various taxol derivatives was investigated, with the objective of better understanding the structural requirements for activity in the taxol series. The 7-hydroxyl group of taxol was derivatized with a photoaffinity label and other reagents as a beginning of the project to understand the interaction of taxol and tubulin, and the activity of all the derivatives in a tubulin assay was determined. A study of the deacylation and reacylation reactions of baccatin 111 was carried out in order to find conditions suitable for the preparation of 2-debenzoylbaccatin Ill , and thus 2-debenzoyltaxol. Finally, the reactions of taxol with various electrophilic reagents were investigated, and the structures of products with an opened oxetane ring and/or contracted ring A were determined. Biological assay results are reported on many of the compounds in this investigation.Ph. D
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
Rearranged taxol compounds and method of using in testing of in vivo activity
No full textIn a preferred embodiment, taxol is treated with mesyl chloride to prepare a taxol derivative with a contracted A-ring, which has comparable activity to taxol in a tubulin depolymerization assay, and which shows cytotoxicity against KB cells in a cell culture assay. In an alternate preferred embodiment, taxol is treated with triethyloxonium tetrafluoroborate (Meerwein's reagent) to produce a taxol derivative with an opened oxetane ring. In another alternate preferred embodiment, reaction of taxol with acetyl chloride yields a taxol derivative in which the oxetane ring is opened and the A-ring is contracted. All of the aforementioned products show in vivo activity in KB cell culture assays. Further, the preferred compounds have different in vivo activities, which makes them ideal to form a range of standards for use in biological testing of other compounds
Chitin-based coatings
No full textA chitosan starting material is combined with a dilute organic acid to produce a chitosonium ion complex. The chitosonium ion complex is then cast, sprayed, extruded, or otherwise processed to produce filaments, coatings, fibers, or the like. Heat is then used to convert the chitosonium ion complex into a N-(C.sub.1-30)acyl glucose amine polymer
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