1,720,982 research outputs found
Long neglected diversity in the Accursed Mountains (western Balkan Peninsula): Ranunculus bertisceus is a genetically and morphologically divergent new species
No full textSouthern European mountain ranges have long been recognized as important hotspots of genetic diversity and areas of high endemism. Reflecting the geographical complexity of these mountain ranges, many European high-mountain species exhibit disjunctions on a variety of geographical scales. One of the long-neglected, poorly investigated and unresolved taxonomic problems concerns Apennine and Balkan members of Ranunculus section Leucoranunculus. According to the most recent taxonomic treatment, this section includes Ranunculus crenatus, distributed predominantly in siliceous massifs of the Carpathians and the Balkan Peninsula, but with a highly disjunct partial distribution area in the eastern Alps, and Ranunculus magellensis, which is usually considered a calcicolous endemic of the central Apennines. However, R. magellensis has also been suggested to occur in the carbonate ranges of the Albanian Alps, which would render this species amphi-Adriatic. We used complementary molecular methods (sequences of the nuclear ribosomal ITS region and of plastid DNA and amplified fragment length polymorphisms), relative genome size measurements and morphometric analyses to elucidate the relationships in Ranunculus section Leucoranunculus. Specifically, we asked if it comprises only a single, widespread and morphologically variable species or several narrowly distributed species with constant morphology. The results of our study showed that populations growing on limestone in the Albanian Alps in northern Albania and southern Montenegro are divergent and should be recognized as a new species, Ranunculus bertisceus Kuzmanović, D.Lakušić, Frajman & Schönsw., sp. nov. These populations differ not only from R. crenatus s.s., which grows on silicates, but also from the calcicolous Apennine endemic R. magellensis. The eastern Alpine populations of R. crenatus, which occur very locally in the Niedere Tauern area, originate from immigration from the Bosnian mountains
Pleistocene survival in three Mediterranean refugia: origin and diversification of the Italian endemic Euphorbia gasparrinii from the E. verrucosa alliance (Euphorbiaceae)
No full textApplying molecular (AFLP and sequences of nuclear ribosomal ITS), karyological (relative genome size estimations and chromosome counts) and morphometric methods we explored the origin of Italian endemic Euphorbia gasparrinii. AFLP data inferred three phylogeographic groups corresponding to Balkan-Central European-northern Italian E. verrucosa, Italian E. gasparrinii and Iberian E. flavicoma. Genetic differentiation among the three species is weak, suggesting their relatively recent divergence. Karyological analyses revealed that populations of E. gasparrinii have 2n = 16 chromosomes, whereas the other two taxa have 2n = 14. This, with weak genetic differentiation and allopatric distribution, supports its recognition as an independent species, despite its weak morphological differentiation. Our study also revealed multiple autopolyploidization events within all three taxa. Contrary to the diploid Apennine populations, the single currently known Sicilian population of E. gasparrinii is tetraploid. It is critically endangered, as the Sicilian distribution has decreased significantly during the past century. Our study underlines the importance of southern European peninsulas as refugial areas during the Pleistocene and provides additional evidence that Mediterranean high mountain plants are suffering severe range contractions due to climate warming
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
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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