1,720,956 research outputs found
Contributo allo studio di lungo termine del Lago Scuro Parmense (Appennino settentrionale): risultati della campagna limnologica condotta nel 1998
No full textRicerche ecologiche in un ambiente acquatico della golena del Po nei pressi di Casalmaggiore
No full textIn questa ricerca sono state studiate le caratteristiche idrochimiche e la composizione della comunità zooplanctonica della Cava Vecchia, una piccola zona umida che viene periodicamente alimentata dalle piene fluviali. I sopralluoghi sono stati condotti da giugno 2000 a giugno 2002. L’elevato trofismo delle acque e il rilevante carico organico sedimentario spesso determinano condizioni di accentuata sottosaturazione dell’ossigeno disciolto. Le concentrazioni di azoto inorganico disciolto rimangono tendenzialmente basse per tutto il corso della ricerca, con alcuni picchi isolati. Le concentrazioni di fosforo reattivo disciolto sono sempre inferiori a 10 μg l-1. Il contenuto di clorofilla a fitoplanctonica è tipico di ambienti ipereutrofici, con un massimo di 915 μg l-1 in aprile 2002. Nello zooplancton sono stati complessivamente identificati 88 taxa. Numericamente dominanti sono alcune specie di Rotiferi microfiltratori, soprattutto dei generi Brachionus, Keratella e Polyarthra, che sostengono picchi di densità di oltre 7000 ind l-1. È da segnalare la presenza di taxa di Rotiferi mai rinvenuti prima in Italia: Rhinoglena tokioensis, Lecane papuana, Cephalodella limosa, Filinia brachiata e F. minuta. Tra i Cladoceri le specie che raggiungono le densità più elevate sono Bosmina longirostris e Moina micrura. I Copepodi Ciclopoidi sono rappresentati per lo più da forme immature. Eudiaptomus gracilis è la sola specie di Copepodi Calanoidi
Impact of a fungal parasite on the reproductive potential of the freshwater calanoid Eudiaptomus intermedius
No full textThe impact of the drought event of summer 2003 on the zooplankton of the Po River (Italy)
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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