1,721,003 research outputs found
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
First complete forefin of the ichthyosaur Grippia longirostris from the Triassic of Spitsbergen
No full textVolume: 41Start Page: 591End Page: 59
Phylogeny of the Ichthyosauria (Amniota: Reptilia) with special reference to Triassic forms
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University of TorontoThe interrelationships among Triassic ichthyosaurs have been poorly understood due to the lack of knowledge regarding their basic osteologies, especially that of the earliest forms from the Spathian (Lower Triassic). These earliest ichthyosaurs represent relatively new additions to our knowledge, most of them having been found during the last 25 years. Reexaminations of ' Utatsusaurus, Grippia, Chaohusaurus' (Early Triassic), 'Parvinatator ' (Early or Middle Triassic), and of 'Mixosaurus' (Middle Triassic), reveals many previously unrecognized features of the skull, dentition, and forefin. This new knowledge, together with preliminary examinations of other Triassic ichthyosaurs, enables a comprehensive comparison among Triassic ichthyosaurs, for the first time. A phylogenetic hypothesis for Triassic ichthyosaurs is proposed, based on cladistic analyses of osteological characters, again for the first time. The monophyly of the Order Ichthyosauria, which was previously never questioned although never explicitly stated, is established based on at least nine characters that unambiguously define the basal node of the Order. Early Triassic ichthyosaurs (including 'Parvinatator') form the stem group of the Ichthyosauria, while all others form a crown-group clade, the Euichthyosauria. This taxon is further divided into two large clades, the Shastasauriformes and Ichthyosauriformes. The former includes 'Cymbospondylus' and 'Shastasaurus ' and their most recent common ancestor, while the latter comprises the Mixosauroidea and Ichthyosauroidea, and their most recent common ancestor. ' Toretocnemus' and 'Californosaurus', which have long been considered as shastasaurids, are shown to be ichthyosauroids. ' Cymbospondylus' and 'Ichthyosaurus', as previously designated, appeared paraphyletic on the cladogram, therefore two new generic names are proposed to solve the problem. 'Omphalosaurus' is considered non-ichthyosaurian, because none of the ichthyosaurian synapomorphies are known for this genus, while it shows several sauropterygian features. The taxonomy of 'Pessopteryx ' should be reconsidered. Tectonic deformation has remarkably distorted the original morphologies of some of the specimens studied, namely all specimens of 'Parvinatator ' and some specimens of Utatsusaurus. A method is devised to retrodeform the images of these specimens, using a personal computer. This method is unique for incorporating matrix algebra, thus simplifying the calculation process, while enabling the statistical selection of best solution.Ph.D
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
Phylogeny of the Ichthyosauria (Amniota: Reptilia) with special reference to Triassic forms
No full textgrantor:
University of TorontoThe interrelationships among Triassic ichthyosaurs have been poorly understood due to the lack of knowledge regarding their basic osteologies, especially that of the earliest forms from the Spathian (Lower Triassic). These earliest ichthyosaurs represent relatively new additions to our knowledge, most of them having been found during the last 25 years. Reexaminations of ' Utatsusaurus, Grippia, Chaohusaurus' (Early Triassic), 'Parvinatator ' (Early or Middle Triassic), and of 'Mixosaurus' (Middle Triassic), reveals many previously unrecognized features of the skull, dentition, and forefin. This new knowledge, together with preliminary examinations of other Triassic ichthyosaurs, enables a comprehensive comparison among Triassic ichthyosaurs, for the first time. A phylogenetic hypothesis for Triassic ichthyosaurs is proposed, based on cladistic analyses of osteological characters, again for the first time. The monophyly of the Order Ichthyosauria, which was previously never questioned although never explicitly stated, is established based on at least nine characters that unambiguously define the basal node of the Order. Early Triassic ichthyosaurs (including 'Parvinatator') form the stem group of the Ichthyosauria, while all others form a crown-group clade, the Euichthyosauria. This taxon is further divided into two large clades, the Shastasauriformes and Ichthyosauriformes. The former includes 'Cymbospondylus' and 'Shastasaurus ' and their most recent common ancestor, while the latter comprises the Mixosauroidea and Ichthyosauroidea, and their most recent common ancestor. ' Toretocnemus' and 'Californosaurus', which have long been considered as shastasaurids, are shown to be ichthyosauroids. ' Cymbospondylus' and 'Ichthyosaurus', as previously designated, appeared paraphyletic on the cladogram, therefore two new generic names are proposed to solve the problem. 'Omphalosaurus' is considered non-ichthyosaurian, because none of the ichthyosaurian synapomorphies are known for this genus, while it shows several sauropterygian features. The taxonomy of 'Pessopteryx ' should be reconsidered. Tectonic deformation has remarkably distorted the original morphologies of some of the specimens studied, namely all specimens of 'Parvinatator ' and some specimens of Utatsusaurus. A method is devised to retrodeform the images of these specimens, using a personal computer. This method is unique for incorporating matrix algebra, thus simplifying the calculation process, while enabling the statistical selection of best solution.Ph.D
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
Estimating body mass from silhouettes: testing the assumption of elliptical body cross-sections /
Get PDFDispelling 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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