1,720,974 research outputs found
A phylogenetic analysis of Dipsacaceae (Dipsacales) based on four DNA regions.
No full textAbstract: Authors studied the phylogeny of Dipsacaceae using maximum parsimony and Bayesian analyses on sequence data from chloroplast (trnL intron, trnL-trnF intergenic spacer, psbB-psbH gene complex) and nuclear genomes (ITS1 and ITS2). Both data partitions as well as their combination show that Dipsacaceae is a monophyletic group. Topology in tribe Scabioseae is similar to those of other recent studies, except for the position of Pycnocomon, which is nested in Lomelosia. Pycnocomon, the pollen and epicalyx morphologies of which closely resemble those of Lomelosia, is interpreted as a psammophilous morphotype of Lomelosia, and its nomenclature has been revised accordingly. Exclusion of Pseudoscabiosa, Pterocephalidium, Pterocephalodes (and probably Bassecoia), Succisa, Succisella from Scabioseae is confirmed. Pterocephalodes hookeri is the sister group to the rest of the family. Its remoteness from Pterocephalus has been confirmed on molecular grounds. Lack of evident synapomorphies for various clades is interpreted as a possible consequence of fast adaptative radiation
Tarocchi, cristalli e partite a scacchi: la narrativa di Italo Calvino tra arte combinatoria e tensione conoscitiva
No full textCalvino non ha perseguìto nei suoi racconti l’introspezione e l’approfondimento psicologico preferendo piuttosto coltivare l’intreccio, la relazione tra i fenomeni e i personaggi in modo da farli interagire in un gioco combinatorio. Le metafore euristiche della sua narrativa sono compendiate nelle caratteristiche che, pur nella loro natura così diversa, accomunano i cristalli, i giochi dei tarocchi e quelli degli scacchi. Le forme dei cristalli sono infinite, ognuna diversa da ogni altra, ma tutte si formano attraverso la sedimentazione sui tre assi della lunghezza, larghezza, altezza. I tarocchi e gli scacchi possono dare vita a infinite partite ma tutte si fondano sulla combinazione di poche carte e di pochi pezzi. Il saggio analizza questo gioco combinatorio in tutte le raccolte di Calvino che volta a volta fa per esempio interagire l’ideale e il reale (Il cavaliere inesistente), l’alto e il basso (Il barone rampante), il buono e il cattivo (Il visconte dimezzato). Analogamente Se una notte d’inverno nasce sullo schema di alternative binarie, così come i ventisette racconti di Palomar si dispongono agli incroci di un sistema combinatorio tra tre aree tematiche. Anche in Marcovaldo, nel Castello e nella Taverna dei destini incrociati e perfino nelle Lezioni americane lo sviluppo diegetico deriva dalla combinazione di un numero ridotto di elementi discreti. In questo modo Calvino vince la propria agorafobia intellettuale, anche se il numero indefinito delle combinazioni lo mette al tempo stesso al riparo dalla nevrosi di segno opposto, quello della claustrofobia
Metafore scientifiche nella prosa di Carlo Emilio Gadda
No full textIl saggio si propone di indagare l'uso delle metafore scientifiche nella prosa di Carlo Emilio Gadda, non solo come documento di contaminazione tra linguaggio letterario e scientifico, ma come dispositivo argomentativo costante, presente sin dalla Meditazione milanese, ma particolarmente efficace nel pamphlet antimussoliniano Eros e Priapo, in cui la dimostrazione della disfunzionalità del fascismo viene dimostrato attraverso una serie di metafore tratte dal mondo dell'elettrotecnica, come quella - da cui viene ricavato il caso di studio analizzato - della "caduta di tensione"
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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