1,721,015 research outputs found
Heterochrony in the evolution of the planktonic foraminifer Globigerinoidesella fistulosa from the <i>Trilobatus sacculifer</i> plexus
No full textPlanktonic foraminifera are extremely well-suited to study evolutionary change in the fossil record due to their high-resolution deposits and global distribution. Species are typically conservative in their shell morphology with the same geometric shapes appearing repeatedly through iterative evolution, but the mechanisms behind the architectural limits on foraminiferal shell shape are still not well understood. To understand when and how these developmental constraints evolve, we study morphological change leading up to the origination of the unusually ornate species Globigerinoidesella fistulosa. We measured the size and circularity of over 900 specimens of G. fistulosa, its ancestor Trilobatus sacculifer and intermediate forms from a site in the Western Equatorial Pacific. Our results show that the origination of G. fistulosa from the Trilobatus sacculifer plexus involved a combination of two heterochronic expressions: earlier onset of protuberances (pre-displacement) and steeper allometric slope (acceleration) as compared to its ancestor. Our work provides a case study of the complex morphological and developmental changes required to produce unusual shell shapes and highlights the importance of developmental changes in evolutionary origination
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
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
Trilobatus Spezzaferri, Kucera, Pearson, Wade, Rappo, Poole, Morard & Stalder 2015
No full text<p> Genus <i>Trilobatus</i> Spezzaferri, Kucera, Pearson, Wade, Rappo, Poole, Morard, & Stalder, 2015</p> <p> <b>Type species.</b> <i>Globigerina triloba</i> Reuss, 1850.</p> <p> <b>Diagnosis.</b> Type of wall: normal perforate, spinose, coarsely cancellate ‘ <i>sacculifer</i> -type’ wall texture, though commonly obscured by a heterogeneous secondary, ‘gametogenic’ calcite. Test morphology: test low trochospiral, three to four usually globose, near-spherical chambers in the final whorl, generally high chamber expansion rate; sutures distinct, depressed, slightly straight to curved on both sides; umbilicus typically narrow; primary aperture usually extraumbilical-umbilical, generally a low arch, numerous apertures on spiral side, one per chamber, placed at the sutures of the preceding chamber and third-previous chamber (see Spezzaferri <i>et al</i>. 2015 for further detail).</p> <p> <b>Remarks.</b> <i>Trilobatus</i> is discerned from its ancestor <i>Globoturborotalita</i> Hofker, 1976 by possessing one or more supplementary apertures on the spiral side. <i>Globigerinoides</i> Cushman, 1927 also possesses supplementary apertures but differs from <i>Trilobatus</i> as the latter possesses a strictly <i>sacculifer</i> - type wall texture, whereas the former exhibits a <i>ruber-</i> or <i>ruber</i> / <i>sacculifer</i> - type wall texture (see Hemleben & Olsson 2006 for wall texture classification). Morphospecies of <i>Globigerinoides</i> also show a tendency towards higher arched primary apertures, whilst those of <i>Trilobatus</i> generally have low-arched, often slit-like primary apertures. <i>Globigerinoidesella</i> differs in having digitate protuberances on the final chamber(s) and usually exhibits a larger test size compared to <i>Trilobatus</i>. See also Spezzaferri <i>et al</i>. (2015, table 2) for comparison of morphological characters.</p> <p> <i>Trilobatus</i> was erected to encompass the ‘ <i>sacculifer</i> lineage’ (<i>sensu</i> Spezzaferri <i>et al</i>. 2015), and distinguish it from the ‘ <i>ruber</i> lineage’, which were both formerly part of <i>Globigerinoides</i> Cushman, 1927. Spezzaferri <i>et al</i>. (2015) demonstrated that the two lineages developed independently and thus placed the two groups in separate genera to avoid polyphyly (see Introduction for further detail).</p> <p> <b>Range.</b> Latest Oligocene to Recent.</p>Published as part of <i>Poole, Christopher R. & Wade, Bridget S., 2019, Systematic taxonomy of the Trilobatus sacculifer plexus and descendant Globigerinoidesella fistulosa (planktonic foraminifera), pp. 1989-2030 in Journal of Systematic Palaeontology 17 (23)</i> on page 1999, DOI: 10.1080/14772019.2019.1578831, <a href="http://zenodo.org/record/10883327">http://zenodo.org/record/10883327</a>
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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