1,720,969 research outputs found
Spatial heterogeneity of spring phytoplankton in a large tropical reservoir: could mass effect homogenize the heterogeneity by species sorting?
No full textReservoirs are river–lake hybrid ecosystems characterized by a marked longitudinal zonation and variable flushing rates depending on the use of stored waters. The structure of their phytoplankton is therefore subjected to the interplay between the environmental conditions of the different zones (species sorting) and the strength of the unidirectional flow (mass effect). The spatial distribution of spring phytoplankton was investigated in a tropical reservoir across its different zones. Phytoplankton displayed heterogeneous spatial patterns from the turbulent, nutrient-rich riverine zones to the relatively stable lacustrine zone. The analysis of this spatial heterogeneity revealed the relative importance of species sorting and mass effect in this morphologically complex reservoir. Different taxonomic groups showed different spatial patterns due to their specific physiological and morphological features, and as a result of the local environmental filtering. In the studied reservoir, the strength of the homogenizing effect of water flow did not smooth the spatial heterogeneity and played a weak role in constraining spring phytoplankton. Actually, water flow contributed to the spatial heterogeneity of phytoplankton by enhancing the local environmental differences caused by an operational drop in water level, and species sorting resulted as the primary forcing in determining spring phytoplankton spatial distribution
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
Spatial structure and β-diversity of phytoplankton in Tibetan Plateau lakes: nestedness or replacement?
No full textSpatial patterns and β-diversity of phytoplankton assemblages depend on the relative importance of species dispersal capacity and species-sorting. Variability in species composition, composed by differences in species richness (nestedness) and/or species replacement, may be caused by niche availability and environmental selection. A field survey was carried out in Tibetan plateau on 38 lakes. Tibetan plateau lakes, located at high elevation, are harsh ecosystems characterized by low temperatures, low available nutrients, high UV amount, and strong salinity gradients. Only well-adapted species can survive in these environments. We therefore hypothesized that environmental filtering was the main factor determining phytoplankton assemblage structure in these lakes, and that species nestedness largely contributed to Î2-diversity. Spatial analysis showed that both environmental variables and broad-scale spatial variables accounted for the variation of phytoplankton assemblages. In particular, phytoplankton was mainly shaped by spatially structured environmental heterogeneity, which resulted in low α-diversity and high Î2-diversity. In contrast to our assumption, species turnover contributed to the majority of Î2-diversity of the studied assemblages. Local environments selected species with the corresponding stress-tolerant traits. Within the narrow range of available niches, environmental filtering of phytoplankton traits induced speciesâ replacement along environmental gradients
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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