1,721,054 research outputs found
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
Vanadate-sensitive activity in olive (Olea europaea L.) calli grown in the presence of auxins and cytokinins.
No full textModificazioni del trascrittoma di due linee pure di mais a diversa NUE durante l’induzione dell’assorbimento del nitrato
No full textIn due linee pure di mais (Lo5, ad alta NUE e T250, a bassa NUE) sono state caratterizzate le modificazioni della velocità di assorbimento del nitrato (induzione) in seguito al contatto fra l’anione e gli apparati radicali per concentrazioni e tempi diversi utilizzando il 15N come tracciante e la successiva determinazione con analisi IRMS. La linea Lo5 rispondeva al trattamento (200 μM di nitrato) più rapidamente (massima induzione a 4 ore) rispetto alla linea T250 (massima induzione a 12 ore).
Sulla base del diverso comportamento mostrato dalle due linee è stata condotta un’analisi microarray “genome-wide” volta ad identificare i meccanismi molecolari coinvolti nelle risposte delle radici delle due linee di mais. E’ stato, infatti sviluppato, sulla base del completa sequenza genomica di mais (www.maizesequence.org), un chip NimbleGen che permette di monitorare dell’espressione di circa 60.000 trascritti.
Il confronto dei profili trascrizionali ottenuti per le due linee suggerisce che esse rispondano al trattamento con il nitrato modulando un numero relativamente ridotto di geni comuni. Le due linee mostrano d’altra parte notevoli differenze nel numero di trascritti differenzialmente espressi. La linea Lo5, concordemente al profilo di induzione, risponde al trattamento rapidamente variando l’espressione di circa 5000 trascritti già dopo due ore di contatto tra apparati radicali e nitrato. Nella linea T250 il trattamento determina la modulazione di un numero inferiore di trascritti (circa 1600 a 12 ore) con un progressivo incremento nel tempo. I risultati mostrano come la risposta al trattamento, che può essere assimilato alle fluttuazioni della concentrazione di nitrato alla rizosfera, coinvolga meccanismi diversi tra le due linee. Ulteriori analisi, basate sull’annotazione dei trascritti, forniranno dettagli riguardo alla modulazione di vie metaboliche diverse tra Lo5 e T250
Tossicita' da Cd in piante di mais (Zea mays L.) S-carenti: Effetto sulla crescita, sul contenuto di clorofilla e sul cammino di assimilazione dello zolfo.
No full textAttivita' carbossilative e contenuto di zuccheri non strutturali in foglie da sfalci di Medicago sativa L. cv Lodi seminate in annate differenti.
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