1,721,495 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
Trattamento endovascolare versus open negli aneurismi rotti dell’aorta addominale, introduzione al tema
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Probiotici sporigeni per l'alimentazione animale
No full textProbiotics are used in animal feeding in order to increase zootechnical performances, such as average daily gain, feed conversion rate, quality of animal products, animal health. Bacterial spore formers, mostly of the genus Bacillus, are very promising for a use as probiotics in animal production. Positive effects of Bacillus spp. administration have been observed, but at present their action is not completely understood. Various hypothesis have been made to explain what happens to ingested spores. Different probiotic mechanisms have been proposed: production of organic acids (SFLAB) or bacteriocins, mucosal adhesion, immunostimulation of GALT. This review suggests the possible use of spore forming bacteria as probiotics in animal production. General information about available spore forming probiotics is given; in particular our attention was focused on B. coagulans. This microorganism is not already commercialized in European Union as additive in animal feeding, but it is already used as human probiotic. Several studies performed on poultry, pigs and calves have shown positive results, suggesting its use for the improvement of zootechnical performances
Valutazione dell'effetto antimicotico dell'ozono gassoso in uno stabilimento di lavorazione di carni fresche
No full textL’ozono è stato sperimentato, in diversi settori, come agente di disinfezione alimentare ed ambientale, grazie alla sua azione ossidante nei confronti delle componenti cellulari; l’effetto microbicida nei confronti dei batteri è noto, mentre la sua azione sui miceti è tuttora incerta. Questo studio è stato svolto per valutare l’efficacia di un impianto di ozonizzazione dell’aria, presso uno stabilimento di lavorazione di carni fresche, nei confronti di miceti potenzialmente contaminanti gli ambienti di lavorazione. Sono stati scelti ed inoculati su piastre Petri contenenti specifici terreni di cultura, tre ceppi fungini di collezione,Aspergillus niger,Penicillium roqueforti,Mucor racemosus ed un ceppo di lievito, Saccharomyces cerevisiae. I ceppi sono stati testati individualmente, posizionando, in tre diversi punti e a tre diverse altezze all’interno del locale di sezionamento carni, quattro piastre per ogni posizione (due inoculate con S. cerevisiae e due inoculate con il ceppo fungino).
Nelle ore notturne le piastre sono state sottoposte, aperte, ad erogazione di ozono gassoso,distribuito in concentrazione di 20 ppm. In seguito al trattamento, le piastre sono state trasportate in Laboratorio ed incubate a 25 ° C e 35 °C per 7-10 giorni.Al termine dell’incubazione, è stata valutata l’efficacia del trattamento, verificando l’eventuale inattivazione dei microrganismi testati(presenza/assenza di colonie sul terreno di coltura). Sono state eseguite due ripetizioni per ogni ceppo fungino e sei ripetizioni per il ceppo di lievito.
L’ozono gassoso non ha mostrato azione inibitoria nei confronti dei ceppi di muffe; si è invece osservata un’azione microbicida significativa nei confronti di S. cerevisiae,
con un abbattimento medio delle cariche di 2.8 logaritmi ed un’azione uniforme in tutti i punti sottoposti a controllo. I risultati ottenuti suggeriscono l’importanza di una definizione puntuale delle condizioni di utilizzo dell’ozono, allo scopo di ottimizzarne l’efficacia antimicrobica nelle condizioni reali di lavorazione delle aziende alimentari
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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