1,720,960 research outputs found
A non-contact method for measuring junction temperature of AlGaInP LED array
No full textDecember 2008School of ArchitectureLighting Research CenterM
Understanding the factors that influence the charging performance of a stand-alone PV-LED system
No full textDecember 2008School of ArchitectureLighting Research CenterM
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
No full textWe 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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Approaches to the synthesis of the macrolactone pyrrolizidine alkaloids (-)-integerrimine and (+)-usaramine
No full textA formal total synthesis of the macrolactone pyrolizidine alkaloid (-)-integerrimine (2), from R-(+)-citronellal (93) is described. Aldehyde 93 was converted to exo methylene derivative 94 which was reduced to allylic alcohol 95. The epoxides 96 and 98, obtained in a ratio of 3:1 respectively by Sharp less epoxidation of 95 with diisopropyl (-)-tartrate, were separated as their 3,5-dinitrobenzoates 97 and 99 . Diol 100, derived from hydride opening of the major epoxide 97, was protected as the bis-3,5-dinitrobenzoate 101, which was oxidatively cleaved at the isopropylidene terminus. Methanolysis of the dinitrobenzoates and acid catalyzed lactonization provided 3-lactone 102, the structure of which was confirmed by X-ray crystallographic analysis. Oxidation of the primary alcohol of 102, followed by introduction of the E-ethylidene group, furnished 31 which has been previously converted to (-)-2 . The Sharpless epoxidation of 95 employing (+)-tartrate furnished 98 and 96 in 96:4 ratio respectively. Epoxide 98 was converted to 102 and hence to 31. Epoxide 98 was also protected as its silyl ether 109 and the olefin was oxidatively cleaved. The resulting carboxylic acid was converted to 110, acid catalyzed opening of which was anchimerically assisted by the ester function to give δ-lactone 112. The primary alcohol of 112 was reduced to a methyl group via iodide 113 and removal of the silyl blocking group from 114 then yielded 102. An approach to the chiral synthesis of (+)-usaramine (5) began from epoxide 98 . The diol 121, derived from opening of 98 with pivalic acid, was protected as the acetonide 122 and the pivalate ester was reduced to give 123. Alcohol 123 was oxidized to carboxylic acid 124 which was converted to methyl ester 125. The latter provided 120, via acid 126, by truncation of the isopropylidene group. Since introduction of the E-ethylidene substituent could not be accomplished on 120, δ-lactone 137 was used as the substrate for the aldol reaction with acetaldehyde. This lactone was prepared from 126 by cleavage of the acetonide, selective protection of the primary hydroxyl of the derived diol as 136, and subsequent lactonization with Mukaiyama's reagent. Introduction of the ethylidene group and deprotection of 138 provided 139. The first chiral synthesis of (-)-140, the dimethyl ester of naturally occurring (+)-retronecic acid (117), was achieved by methanolysis of 139. The ester 130 was prepared by titanate-mediated transesterification of 125 with 2-(trimethylsilyl)ethanol and subsequent oxidative cleavage of the olefin. This carboxyl terminus of 130 was coupled with the retronecine derivative 26 via anhydride 150 to yield 143. A nucleophilic macrolactonization protocol was attempted on 151, which was obtained by selective desilylation of 143, but this unexpectedly provided 153 instead of the macrolactone 149. Further treatment of 153 with excess fluoride at elevated temperature yielded the macrolactone 149, which contains the carbon skeleton and stereochemistry of (+)-usaramine (5) but lacks the ethylidene side chain
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
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