1,721,027 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
Water-cover influences on diatom ingestion rates by meiobenthic copepods
Full text linkLaboratory experiments on meiobenthic copepods using 14C-diatoms were conducted to investigate whether: (1) feeding rates or (2) food sources (planktonically-suspended foods or benthic sediment-associated foods) vary in response to the presence or absence of water-cover (i.e. simulated Higher-water vs Low-water conditions). Three diatom-feeding harpacticoids were examined. Scottolana canadensis feeds at significantly higher rates (2x) during Higher-water (HW) conditions (P\u3c0.001), at which time it consumes planktonic foods; during Low-water (LW), feeding is greatly reduced. These feeding patterns are related to its burrow-dwelling and to its subtidal habitat. Cletocamptus deitersi remains virtually unaffected by changes in ambient water-cover, feeding at nearly equal rates during HW and LW conditions but always tending to consume more benthic diatoms. Microarthridion littorale consumes food at nearly equal rates during HW and LW conditions, but does so by shifting its feeding mode. During HW-times it makes excursions into the water column, feeding on planktonically-suspended foods. During LW-times it feeds benthically, moving over the sediment surface. Such feeding differences must affect meso-scale distributions of meiobenthos in the field, total benthic consumption and energy-flow estimates over a tidal-cycle, and the coupling of benthic and pelagic systems
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
How do harpacticoid grazing rates differ over a tidal cycle? Field verification using chlorophyll-pigment analyses
Full text linkFour species of meiobenthic copepods were examined for diatom feeding. Microscopic analysis of gut-pellet contents from field-collected individuals indicated frequent ingestion of diatoms by 3 harpacticoids (Scottolana canadensis, Microarthridion littorale, Cletocamptus deitersi) while occasional diatom ingestion occurred Paronychocamptus huntsmani. Frustules were usually empty and broken, indicating that contents were digested. Laboratory experiments using 14C-labeling showed assimilation of diatoms by the 3 species examined. Field grazing rate studies were conducted over different portions of a tidal cycle using fluorescent chlorophyll-pigment analysis of gut-contents. Highest diatom consumption (p\u3c0.05) occurred just after the mudflat became exposed (i.e. Early Low Water level, ELW) for S. canadensis, while consumption at Late Low Water (LLW, i.e. after mudflat is exposed for several hours) was reduced. M. littorale showed a somewhat similar pattern in that highest consumption rates (p\u3c0.05) also occurred during ELW. However, during High Water (HW) and LLW a similar (but reduced) feeding rate was measured. P. hunstmani appeared to only ingest diatoms (i.e. chl-pigments) during HW. Relationships of feeding processes over a tidal cycle are discussed with regard to distributional patterns in intertidal and subtidal habitats
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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