1,720,989 research outputs found
Spazio alle idee
No full textUtilizzo di tecnologie e sistemi costruttivi sostenibili nel progetto di ristrutturazione e ampliamento di fabbricato sito in Bologna, quartiere Bolognina. Progettisti: L. Bonavita, A. M. Manferdini. Progetto e realizzazione: 2006-200
Chemoselective synthesis of pyrazole derivatives via beta-enamino keto esters
No full textbeta -Enamino keto ester (2a) reacts with hydroxylamine to give an isoxazole derivative (3). Compound (2a) reacts with hydrazine, alkyl- and arylhydrazines to give pyrazole derivatives (4a-e) as only reaction products. Methylation of compound (4a) afforded the two isomeric pyrazole derivatives (4b) and (5)
Synthesis of pyrazole C-nucleosides via Tin(IV) chloride-promoted reactions of beta-D-ribofuranosyl cyanide with beta-dicarbonyl compounds
No full text2,3,5-Tri-O-benzoyl-beta-D-ribofuranosyl cyanide reacts with methyl acetoacetate and diethyl malonate in the presence of stoichiometric amounts of SnCl4 to give a beta-D-ribofuranosyl-enaminoketoester and a beta-D-ribofuranosyl-enaminodiester, respectively. The beta-D-ribofuranosyl-enaminoketoester was debenzoylated, treated with 2,2-dimethoxypropane and tert-butyl-dimethylsilyl chloride to give the methyl 3-amino-3-(5'-O-tert-butyldimethylsilyl-2',3'-O-isopropylidene-beta-D-ribofuranosyl)-2-acetyl propanoate obtained in good yield together with small amounts of its alpha-anomer. The reactions of the beta-anomer with hydrazine, methyl- and phenylhydrazine carried out under controlled experimental conditions, afforded the pyrazole C-nucleosides in good yields as beta-anomers. (C) 2002 Elsevier Science Ltd. All rights reserved
A new route to the synthesis of pyrazole and pyrimidine C-nucleoside derivatives
No full textA new route to the synthesis of pyrazole and pyrimidine C-nucleosides, which involves as the key step a metal promoted reaction of beta-D-ribofuranosyl ketoesters with alkyl cyanoformates is described. 2,3,5-Tri-O-benzoyl-beta-D-ribofuranosyl cyanide 1 reacts with alpha-bromoesters, in the presence of zinc dust, to give beta-D-ribofuranosyl-enaminoesters 2 which are hydrolysed with IN hydrochloric acid to beta-ketoesters 3. The reactions of beta-ketoesters 3 with alkyl cyanoformates, in the presence of tin(IV) chloride or of catalytic amounts of metal acetylacetonates, afford beta-D-ribofuranosyl enaminoketoesters 4. These compounds react with benzylhydrazine and acetamidine to give pyrazole and pyrimidine C-nucleosides (6,7). (C) 1999 Elsevier Science Ltd. All rights reserved
Metodiche integrate di rilievo 3D per l’analisi di architetture complesse. Il caso dell’Abbazia di Pomposa
No full text(abstract italiano) Nel campo del rilievo architettonico l'integrazione fra differenti metodi di acquisizione digitale tridimensionali consente di sopperire ai limiti dei singoli approcci per ottenere modelli sempre più completi, dai quali poter estrarre un numero di informazioni utili per differenti analisi. Questo contributo presenta una metodologia di rilievo integrata fra strumenti attivi e passivi, applicati da terra e da drone, al fine di ottenere un modello multi-risoluzione completo. Il caso studio oggetto della sperimentazione è l'Abbazia di Pomposa, a Codigoro (FE). //// (abstract inglese) In the field of digital 3D survey, integration among different methodologies and technologies offers the opportunity to overcome lacks of single techniques, building more complete and faithful 3D models and therefore deriving information that can be used for different kind of investigations. This contribution shows an integrated methodology between active and passive technologies applied from terrestrial and UAV point of views, aimed at creating complete and multi-resolution 3D models. The selected case study is the Pomposa Abbey, located near Ferrara, Italy
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
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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