1,720,955 research outputs found
Variabilità spaziale dell'albedo sulle aree glaciali dell'Alta Val de La Mare (Gruppo Ortles-Cevedale)
No full textNell’ambito di un progetto di ricerca sulla criosfera e sugli effetti idrologici delle variazioni climatiche nei bacini di alta quota, è stato eseguito uno studio sulla va- riabilità spaziale dell’albedo in ghiacciaio. La campagna di rilievi è stata condotta nelle estati del 2007 e del 2008 sui ghiacciai dell’alta Val de La Mare (Gruppo Ortles-Cevedale, Trentino).
L’albedo regola la quantità di radiazione ad onde corte assorbita dalla superficie ed è quindi determinante nel modulare il bilancio energetico e il bilancio di massa glaciale. Le parametrizzazioni comunemente riportate nella letteratura scientifica sono generalmente orientate alla descrizione della variabilità spazio-temporale dell’albedo della neve, mentre l’albedo del ghiaccio è spesso assunto costante o parametrizzato in modo molto più semplice, ad esempio in funzione della quota. I rilievi eseguiti in alta Val de La Mare evidenziano un’elevata variabilità dell’albe- do del ghiaccio di ghiacciaio, che è funzione soprattutto della copertura detritica superficiale. Sulla base di queste osservazioni, si è cercato di mettere a punto un metodo speditivo che consente una valutazione semplice ed affidabile dell’albedo, basato su rilievi fotografici da terra. I risultati ottenuti confermano che il metodo proposto consente di cogliere in modo adeguato la variabilità spaziale dell’albedo sul ghiaccio di ghiacciaio
PALLADIUM-CATALYZED REACTION BETWEEN ARYL OR ALKENYL HALIDES AND (1-CARBALKOXY-1-ALKENYL)ZINC IODIDES - A NEW CLASS OF UNMASKED BETA-SUBSTITUTED ACRYLATE ALPHA-ANION EQUIVALENTS
No full textUnmasked beta-substituted acrylate alpha-anion equivalents have been directly and very efficiently prepared by insertion of zinc metal into the carbon-iodine bonds of alkyl (E)- or (Z)-2-iodo-2-alkenoates, (E)- or (Z)-(4), respectively. The stereoisomeric composition of these new reagents, 12, depends on the experimental conditions used for their preparation. Their Pd0-catalyzed reaction with alkenyl or aryl halides, which can contain functional groups, leads chemoselectively to the corresponding cross-coupled products in high yields. When the reagents 12 are synthesized from compounds (Z)-4 or long reaction times are used for their preparation, their cross-coupled products result are rich in the stereoisomers with trisubstituted double bonds of (E)-configuration
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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