1,720,957 research outputs found
Biodiversity evaluation of the macroalgal flora of the Gulf of Trieste (Northern Adriatic Sea) using taxonomic distinctness indices
No full textRecently a new index has been proposed for the evaluation of biodiversity: taxonomic distinctness. One of the positive features of this index is that it is neither sampling-effort nor sample-size dependent. Until now, its application has been limited to the assessment of zoobenthos and fish biodiversity.
The main objective of this paper was to test the applicability of this index to the macroalgal flora of the Gulf of Trieste (Northern Adriatic Sea). For this purpose the flora recently censused in this area was compared with a checklist of the entire region compiled from the literature. Two indices were mainly used for this study: average taxonomic distinctness based on presence/absence data (AvTD), and variation in taxonomic distinctness (VarTD). Their relationship with species richness was also assessed. The distinctness was compared with statistically significant limits estimated using randomisation tests made on the local master species list. On the same data set multivariate analysis based on a taxonomic similarity index was performed, and a 2nd stage MDS was used to compare results at four taxonomic levels.
The results confirmed that statistical over-threshold situations can be highlighted only by one index (AvTD or VarTD) or only by their relationship (AvTD vs VarTD) and not necessarily at the same time by both indices and their relationship. While the average distinctness (AvTD) did not show values significantly different from the expected ones, the variation (VarTD) in one site showed values significantly exceeding confidence limits. This situation has already been described for zoobenthic communities and explained as a consequence of a decrease in habitat diversity. In this case it might be the result of the reduced presence of hard substrata suitable for macroalgal colonisation.
The joint analysis of both parameters (AvTD vs VarTD) revealed one site exceeding the 95% confidence limit, which was not identified by analysing only one parameter at a time. This significant over-threshold pattern in the relationship of the distinctness indices could be explained by a relative increase of Rhodophyceae, attributable to the intensive grazing of the sea urchins at this site. The analysis of taxonomic distinctness indices at each site compared with the 95% probability funnels or ellipses derived from the regional species pool gave results consistent with the ones obtained using multivariate analysis. The results of this study suggest that the method may have more general validity
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
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