1,720,982 research outputs found
Metazoan diversity and seasonality through eDNA metabarcoding at a Mediterranean long-term ecological research site
No full textMetabarcoding of environmental DNA has provided striking insights into marine microbial diversity. With this approach, we assessed the diversity of metazoan assemblages and their temporal variations at the Long-Term Ecological Research site MareChiara (LTER-MC) in the Gulf of Naples (Mediterranean Sea). The Illumina sequencing of the V4-18S rRNA fragment from 48 surface samples collected from 2011 to 2013 produced a total of 5 011 047 marine metazoan reads. The normalized dataset was generally dominated by copepods (60.3%), followed by annelids (34.7%) mostly represented by the invasive benthic polychaete Hydroides elegans. Non-copepod holoplankton was mainly represented by siphonophores, rotifers, and appendicularians, with occasional mass occurrences of jellyfish. The rest of meroplankton (mainly molluscs, annelids, and anthozoans) showed a high diversity, covering all 11 zooplankton phyla, from Porifera to Craniata. A high number of copepod genera were identified, with seasonal recurrence matching patterns observed in 30 years of studies in the Gulf of Naples. Despite limitations related to the molecular marker resolution and reference dataset, the study provided valuable insights into diversity and seasonal patterns of the whole metazoan assemblage, expanding the knowledge on rare or hardly identifiable taxa and confirming DNA metabarcoding as a powerful approach to be integrated at LTER sites
The poly(ADP-ribosyl)ation system in the crustacean copepod Temora stylifera (Dana, 1853–1855) from a coastal area of the Mediterranean Sea: a new biomarker of the health status
No full textZooplankton size structure in the Gulf of Tadjoura (Djibouti) during whale shark sighting: a preliminary study
No full textZooplankton, collected in the Gulf of Tadjoura (Republic of Djibouti) during a cruise conducted to study the feeding behavior of the whale shark Rhincodon typus, was analyzed in terms of size class, abundance and species composition. This pilot study was aimed to better understand a possible correlation between mesozooplankton composition and size spectra, collected up to 10 m depth, and different feeding behaviour of R. typus. Our data indicate that holoplankton accounted from 93 to 100% of the total community, copepods represented more than 80% of the zooplanktonic community, with 14 copepod genera and 9 species. Our preliminary results suggest an association between suction feeding activity of R. typus and high abundance of small copepod species. Passive feeding was recorded during the lowest abundance of zooplankton, mainly composed by large chaetognaths and larvae of Belbezub hansenii belonging to the family of Luciferidae (Sergestids). These first results highlight the importance of analyzing the dimensional structure of mesozooplankton in the aggregation areas of whale shark and open up new and intriguing investigative approaches to better understand the biology of R. typus
A network of Italian amphipodologists in the frame of MOTax (Marine Organisms Taxonomy) at the Stazione Zoologica Anton Dohrn di Napoli (Italy)
No full textZooplankton size structure in the Gulf of Tadjoura (Djibouti) during whale shark sighting: a preliminary study|Structure de taille du zooplancton du Golfe de Tadjoura (Djibouti) pendant l’observation de requins baleines: étude préliminaire
No full textZooplankton, collected in the Gulf of Tadjoura (Republic of Djibouti) during a cruise conducted to study the feeding behavior of the whale shark Rhincodon typus, was analyzed in terms of size class, abundance and species composition. This pilot study was aimed to better understand a possible correlation between mesozooplankton composition and size spectra, collected up to 10 m depth, and different feeding behaviour of R. typus. Our data indicate that holoplankton accounted from 93 to 100% of the total community, copepods represented more than 80% of the zooplanktonic community, with 14 copepod genera and 9 species. Our preliminary results suggest an association between suction feeding activity of R. typus and high abundance of small copepod species. Passive feeding was recorded during the lowest abundance of zooplankton, mainly composed by large chaetognaths and larvae of Belbezub hansenii belonging to the family of Luciferidae (Sergestids). These first results highlight the importance of analyzing the dimensional structure of mesozooplankton in the aggregation areas of whale shark and open up new and intriguing investigative approaches to better understand the biology of R. typus
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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