1,721,466 research outputs found
Towards a total synthesis of trichodermal and colodendrolide via a common key intermediate
No full textThe synthesis of trichodermol (2) was investigated. The A-ring was formed by Diels-Alder reactions, which produced (2-furoyl) substituted cyclohexenes (30) and (36) with the tertiary methyl in its required position. The high yielding adduct (36) was prepared because of the low yield of adduct (30). Problems were encountered in trying to obtain a 1,3-hydroxyketone; even a protected alcohol α to a silylenol ether eliminated readily to form the enone. Consequently the 1,3-diol (59), with two of the methyls in position, was obtained by epoxidation of the enone (40), followed by reduction of the alkene and then the epoxyketone. The rest of the molecule was to be formed by elaboration of ring opened furfuryl or furanyl derivatives. In the event these gave rise to either benzofuran (33), (60) or 6-(cyclohexenyl)-pyran-2,5-dione compounds (41), rather than the sought after benzopran. The methodology for preparing furoyl substituted cyclohexenes was also applied to a model study of the synthesis of calodendrolide (65). The ketones (92) and (102), with both the vinyl and tertiary methyls in place, were readily converted to acetoxy derivatives functionalised in the 2-position, (98), (100), (104) and (105), by reduction and then esterification. All three alcohol protection-deprotection systems investigated failed; trimethylsilyl was too labile and both tert-butyl dimethylsilyl and tetrahydro-2H-pyran presented removal problems.bf 40-1019, 40-1020 withdrawn.</p
Some aspects of public and private in fifth century BC Athens
No full textSIGLEAvailable from British Library Document Supply Centre- DSC:D31910/80 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
JOHNSON, Susan Moore & PAPAY, John. Redesigning Teacher Pay – A System for the Next Generation of Educators. EPI, volume 2: USA, 2009
Full text linkJOHNSON, Susan Moore & PAPAY, John. Redesigning Teacher Pay – A System for the Next Generation of Educators. EPI, volume 2: USA, 200
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
Trained librarian
No full textCitation: Johnson, Susan Effle. Trained librarian. Senior thesis, Kansas State Agricultural College, 1896.Morse Department of Special CollectionsIntroduction: It is in this age when intellectual growth is so rapid, when hundreds of publishing firms send out thousands of pamphlets, magazines, and books daily that we need the librarians. In the future the work of the librarian will be very different from that of the past. As the world has advanced and the people have become cultured and care more for good reading, the librarians have marched to the front. The libraries of the country have become more numerous and with the increase of the libraries has come the need of more librarians; as the need for more workers becomes greater so, too, is the world calling for better work, hence for those who expect to take up this profession, there is great advantage in being trained for the library or the work of the librarians
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
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
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