1,721,172 research outputs found
The GEM detectors for the innermost region of the forward muon station of the LHCb experiment
Full text linkL'esperimento LHCb operera' sull'acceleratore LHC al CERN e avra' inizio nel 2008. Esso e' dedicato ad accurate misure di violazione di CP e di decadimenti rari nel settore del quark b.
Nella tesi viene riportato il lavoro svolto su due aspetti dell'esperimento LHCb: il contributo principale e' lo sviluppo e la costruzione di un rivelatore basato sulla tecnologia Gas Electron Multiplier (GEM), per la strumentazione della regione ad elevato flusso di particelle intorno alla beam pipe della prima stazione per muoni dell'apparato; nella seconda parte viene investigata la possibilita' di osservare il decadimento raro del D0 in due muoni, dimostrando che l'esperimento puo' trovare anche applicazione nel settore della fisica del charmThe LHCb experiment will take place at the LHC accelerator at CERN and will start in 2008. It is dedicated to precise measurements of CP violation and rare decays in the b quark sector.
This thesis reports the work performed on two aspects of the LHCb experiment: the main
contribution is the development and the construction of a detector based on Gas Electron Multiplier (GEM) technology, for the instrumentation of the high irradiated region around the beam pipe of the first Muon Station of the apparatus; in the second part the possibility of the search
of the rare dimuonic D0 decay at the LHCb experiment is investigated, demonstrating that the experiment can found application also in the charm sector physics
Facile reaction of thiols and amines with alkyl-4-hydroxy-2-alkynoates in water under neutral conditions and ultrasound irradiation
No full textThis Letter describes an alternative protocol for the Michael addition of thiols to 4-hydroxy-2-alkynoates. The reaction proceeds at room temperature in water under ultrasound irradiation. With amines instead of thiols a sequential conjugate addition/lactonization reaction leads to important 4-amino-furan-2-one derivatives. (c) 2009 Elsevier Ltd. All rights reserve
Silver-catalyzed direct couplings of 2-substituted furans with cyclic 1,3-dicarbonyls
No full textDirect alkenylation of 2-substituted furans with cyclic 1;3-dicarbonyls by means of silver catalysis have been explored. Silver salts resulted more efficient than a variety of Lewis acids and p-TsOH
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
Sequential alkylation/gold-catalyzed annulation reactions of anilines with propargylic bromide derivatives
No full text"Preliminary results of sequential alkylation\/gold-catalyzed annulation reactions of anilines with propargylic. bromide derivatives to provide quinoline scaffolds are described. The efficiency of NaAuCl42H2O in. the sequential procedure was investigated and compared with different transition metal salts and Au(I). complexes. Selectivity of the reaction of aniline derivatives with propargylic bromides has also been. investigated.
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