1,720,989 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
Evolutionary biology of wood-eating sea urchins (temnopleuridea: Trigonocidaridae)
Get PDFEchinoids comprise a diverse group of Echinoderms composed of around 1000 extant species. The sea urchin family, Trigonocidaridae exemplifies echinoid diversity, being found in almost every marine ecoregion from the intertidal zone to depths over 3,000 m. Some of the Trigonocidaridae are also known wood-eaters, an unusual behavior previously recorded in only three sea urchin species. The family is also characterized by miniature body size and sculpturing of the test. This study is the first phylogeny of the Trigonocidaridae inferred from morphological and molecular evidence. All morphological analyses support the monophyly of the family Trigonocidaridae as well as the monophyly of the clades Trigonocidaris + Genocidaris + Desmechinus, and Hypsiechinus + Prionechinus + Asterechinus (which is monotypic). The molecular analysis does not contradict the morphological analyses and shows strong support for a relationship between Asterechinus and Prionechinus. The evolution of wood-eating and the biogeography of the Trigonocidaridae are explored using this phylogeny
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
Phylogenetic revision of the micro-echinoid genus, Echinocyamus
Get PDFSea urchins (Echinoidea) comprise a group exhibiting enormous diversity in shape and size. At the lowest end of the size scale is Echinocyamus, a poorly known genus of highly miniaturized relatives of the sand dollars sometimes called "sea peas." There are sixteen known extant species of Echinocyamus and two species in the sister genus, Mortonia. Using elliptical Fourier analysis to compare these species, 13 of them with sufficiently large sample sizes (> ten specimens) were significantly distinct based on test shape alone. A morphological phylogeny indicates that two species, E. planissimus and E. platytatus, should be removed not only from the genus, but from the family to which they belonged, Fibulariidae. With the removal of these two species, Echinocyamus and Mortonia are monophyletic and sister to Fibularia. Mortonia was nested well within Echinocyamus and should be sunk into that genus
“A barrel of sponges: a Xestospongia testudinaria species complex in the Verde Island Passage, Philippines”
Get PDFThe giant barrel sponge Xestospongia testudinaria is a dominant member of the coral reef community in the Verde Island Passage (VIP) in the Philippines. However, little is known about its morphology and gene flow. Barrel sponge morphotypes, osculum diameter, body circumference, body length, spicule length, and spicule width were all recorded, analyzed and combined with mitochondrial COI gene results to establish a possible pattern useful to understand or refute the morphological concept of barrel sponge classification. ABGD analysis revealed four haplotypes for the VIP. Spicule variation showed no significant differences and no correlation among sites and haplotypes. On the other hand, colony dimensions showed no significant difference and no correlation among sites and haplotypes. Colony form showed significant variation within and among sites and significant differences linked with haplotypes. My research findings agree with global studies on barrel sponges, showing the vast majority of Xestospongia (including X. muta from the Caribbean) are of the same haplotype. The lack of variation between the common haplotype of X. testudinaria and X. muta suggests that X muta from the Caribbean is the same species as X testudinaria. Interestingly, the Coral Triangle region of the Indo-Pacific showed greater variation in haplotypes, especially within Indonesia and the Philippines than between these areas of the Coral Triangle and the rest of the world
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
Living and fossil genera of the Clypeasteroida (Echinoidea, Echinodermata) : an illustrated key and annotated checklist
No full text- …
