1,721,046 research outputs found
Pycnoclavella stolonialis n. sp. (Tunicata: Ascidiacea), with phylogenetic and distributional remarks on the genus in Europe
No full textPérez-Portela, R., Goodwin, C.E., Picton, B.E., Turon, X. (2010): Pycnoclavella stolonialis n. sp. (Tunicata: Ascidiacea), with phylogenetic and distributional remarks on the genus in Europe. Zootaxa 2407 (1): 51-66, DOI: 10.11646/zootaxa.2407.1.3, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.2407.1.
FIGURE 2. Pycnoclavella stolonialis. a in Pycnoclavella stolonialis n. sp. (Tunicata: Ascidiacea), with phylogenetic and distributional remarks on the genus in Europe
No full textFIGURE 2. Pycnoclavella stolonialis. a) Colonies, a1) and a2) Live colonies close up, neural ganglion visible as a rounded colourless dot; b) colony structure; c) Zooid morphology, c1) zooid removed from the tunic showing testes and ovary, c2) dorsal view of the gut loop and gonads, and c3) right view of the gut loop; d) thorax in lateral view showing stigmata rows, oral tentacles and muscular bands; e) Thorax incubating embryos; f) larvaPublished as part of Pérez-Portela, R., Goodwin, C.E., Picton, B.E. & Turon, X., 2010, Pycnoclavella stolonialis n. sp. (Tunicata: Ascidiacea), with phylogenetic and distributional remarks on the genus in Europe, pp. 51-66 in Zootaxa 2407 (1) on page 55, DOI: 10.11646/zootaxa.2407.1.3, http://zenodo.org/record/530910
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
Dataset for "From metabarcoding to metaphylogeography: separating the wheat from the chaff"
No full textThis dataset contains files with the relevant information on a metabarcoding dataset used as a case study to test the feasibility of performing phylogeographical studies on metabarcoding data, by Turon X, Antich A, Palacin C, Praebel, K and Wangensteen OS.
Abstract of the manuscript:
1. Metabarcoding is by now a well-established method for biodiversity assessment. Metabarcoding datasets are usually used for α- and β-diversity estimates, that is, interspecies (or inter-MOTU) patterns, but they contain an enormous amount of intraspecies (intra-MOTU) information - so far untapped.
2. The use of COI amplicons is gaining momentum in metabarcoding studies targeting many eukaryote groups. COI has for a long time been the marker of choice in population genetics and phylogeography studies. Therefore, COI metabarcoding datasets can be used to study intraspecies patterns and phylogeographic features for hundreds of species simultaneously, opening a new field which we suggest to name metaphylogeography.
3. The main challenge for the implementation of this approach is the separation of erroneous sequences from true intra-MOTU variation. Here, we develop a cleaning protocol based on changes in entropy of the different codon positions of the COI sequence, together with co-occurrence patterns of sequences.
4. Using a dataset of community DNA from several benthic littoral communities in the Mediterranean and Atlantic seas, we first tested by simulation on a subset of sequences a two-step cleaning approach consisting of a denoising step followed by a minimal abundance filtering. The procedure was then applied to the whole dataset.
5. We obtained a total of 563 MOTUs that were usable for phylogeographic inference. We used semiquantitative rank data instead of read abundances to perform AMOVAs and haplotype networks. Genetic variability was mainly concentrated within samples, but with an important between-seas component as well. There were inter-group differences in the amount of variability between and within communities in each sea. For two species the results could be compared with traditional Sanger sequence data available for the same zones, giving similar patterns.
6. Our study shows that metabarcoding data can be used to infer intra- and interpopulation genetic variability of many species at a time, providing a new method with great potential for basic biogeography, connectivity and dispersal questions and for the more applied fields of conservation genetics, invasion genetics, and design of protected areas
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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