1,721,151 research outputs found
Ptychoderidae Spengel 1893
No full textFamily Ptychoderidae Spengel, 1893Published as part of Cameron, Christopher B. & Ostiguy, Angélica, 2013, Three new species of Glossobalanus (Hemichordata: Enteropneusta: Ptychoderidae) from western North America, pp. 143-154 in Zootaxa 3630 (1) on page 144, DOI: 10.11646/zootaxa.3630.1.5, http://zenodo.org/record/21949
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
Fossilization processes of graptolites: insights from the experimental decay of Rhabdopleura sp. (Pterobranchia)
Get PDFLaboratory experiments documenting the decomposition pattern of extant organisms are used to reconstruct the anatomy and taphonomy of fossil taxa. The subclass Graptolithina (Hemichordata: Pterobranchia) is a significant fossil taxon of the Palaeozoic era, represented by just one modern genus, Rhabdopleura. The rich graptolite fossil record is characterized by an almost total absence of fossil zooids. Here we investigated the temporal decay pattern of Rhabdopleura sp. tubes, stolons and single zooids removed from the tubarium. Tubes showed decay after four days, when fuselli began to separate from the tube walls. This rapid loss may explain the absence of fuselli from some graptolite fossils. The black stolon did not show decay until day 155. One day after their removal, zooids quickly decomposed in the following temporal sequence: (1) tentacles; (2) ectoderm; (3) arms; (4) gut; (5) cephalic shield, leading to complete disappearance of recognizable body parts in the majority of experimental zooids within 64–104 h. The most resistant zooid features to decay (61 days) were black-pigmented granules. These results indicate that tubes and the black stolon would persist for weeks across death, transport and burial, whereas a complete decay of zooid features occurs in few days, providing an explanation for the overall poor record of fossil graptolite zooids and suggesting that recorded silhouettes of fossil zooids may be attributed to fossil decay-resistant pigments
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
Glossobalanus Spengel 1893
No full textGenus Glossobalanus Spengel, 1893 Glossobalanus Spengel: van der Horst 1939. Diagnosis. Only genital ridges are present, never genital wings. These ridges usually extend into the hepatic region. Gill slits are small. Hepatic caeca are arranged in two regular rows. The 'cauliflower organ' is absent. (Glossobalanus ruficollis has neither genital ridges nor hepatic caeca, but it has a 'cauliflower organ'.) The central canals of the collar nerve cord may be well formed or may be reduced. The lateral septa are attached to the tips of the genital ridges (except in the case of G. marginatus). Only primary gonads occur, but both dorsal and ventral gonads are present and open to the exterior usually on the tip of the genital ridge. A ciliated streak is found only on the left side of the gut in the abdominal region (except in G. hedleyi, which has both the right and the left). Remarks. We provide an augmented summary of the sole species already described from the west coast of North America, Glossobalanus berkeleyi Willey, 1931, and add to it new descriptions of three additional species from the same coast, G. williami, G. hartmanae (Fig. 1 A) and Glossobalanus barnharti (Fig. 1 B).Published as part of Cameron, Christopher B. & Ostiguy, Angélica, 2013, Three new species of Glossobalanus (Hemichordata: Enteropneusta: Ptychoderidae) from western North America, pp. 143-154 in Zootaxa 3630 (1) on page 145, DOI: 10.11646/zootaxa.3630.1.5, http://zenodo.org/record/21949
Ptychoderidae Spengel
No full textPtychoderidae Spengel: van der Horst 1939. Diagnosis. The occurrence of lateral septa in the trunk and the invariable absence of abdominal pores characterize this family. There is no vermiform process to the stomochord. Dorsal nerve roots in the collar are present and the skeletal cornua rarely reach beyond the anterior half of the collar. Synapticulae form bridges between the primary and secondary gill bars in the pharynx, and hepatic caeca are usually present. There are dorsolateral ciliated grooves in the abdominal part of the alimentary canal. The circular muscle fibers in the trunk are usually outside the longitudinal fibers. Development occurs through a typical tornaria larva. Remarks. Species of all three genera included in this family, namely, Ptychodera, Glossobalanus and Balanoglossus, have been collected from the area under consideration.Published as part of Cameron, Christopher B. & Ostiguy, Angélica, 2013, Three new species of Glossobalanus (Hemichordata: Enteropneusta: Ptychoderidae) from western North America, pp. 143-154 in Zootaxa 3630 (1) on page 144, DOI: 10.11646/zootaxa.3630.1.5, http://zenodo.org/record/21949
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