1,721,052 research outputs found
The application of molecular data to the phylogenetic delimitation of species in bryophytes: A note of caution
No full textVanderpoorten, Alain, Shaw, A. Jonathan (2010): The application of molecular data to the phylogenetic delimitation of species in bryophytes: A note of caution. Phytotaxa 9: 229-237, DOI: 10.11646/phytotaxa.9.1.1
<strong>Bryophytes:The closest living relatives of early land plants Title page</strong>
No full textKonrat, Matt Von, Shaw, A. Jonathan, Renzaglia, Karen Sue, Konrat, Matt Von, Shaw, A. Jonathan, Renzaglia, Karen Sue (2010): <strong>Bryophytes:The closest living relatives of early land plants Title page</strong>. Phytotaxa 9 (1): 3-4, DOI: 10.11646/PHYTOTAXA.9.1.1, URL: http://dx.doi.org/10.11646/phytotaxa.9.1.
FIGURE 3 in A special issue of Phytotaxa dedicated to Bryophytes: The closest living relatives of early land plants
No full textFIGURE 3. Sphagnum pulchrum (Lindberg 1880: 25) Warnstorf (1900: 42), Alaska (Photo: Blanka Shaw). Sphagnum comprises a speciose clade of mosses that dominates many wetland ecosystems, especially in the boreal zone of the Northern Hemisphere (Shaw et al. 2003). In particular, Sphagnum is an important and conspicuous component in peatlands, which perform a significant global function in regulating the Earth's atmospheric chemistry as well as providing valuable economic commodities (Rochefort 2000). Sphagnum holds an interesting position amongst mosses, with Cox et al. (2004) indicating that Sphagnum and Takakia form a clade sister to all remaining mosses.Published as part of <i>Konrat, Matt Von, Shaw, A. Jonathan & Renzaglia, Karen Sue, 2010, A special issue of Phytotaxa dedicated to Bryophytes: The closest living relatives of early land plants, pp. 5-10 in Phytotaxa 9 (1)</i> on page 8, DOI: 10.11646/phytotaxa.9.1.3, <a href="http://zenodo.org/record/10087086">http://zenodo.org/record/10087086</a>
A phylogeny of Adelanthaceae (Jungermanniales, Marchantiophyta) based on nuclear and chloroplast DNA markers, with comments on classification, cryptic speciation and biogeography
No full textAdelanthaceae (including Jamesoniellaceae) represent a major lineage of jungermannialean liverworts that is characterized by ventral-intercalary, often flagelliform branches, succubous leaves, ovoid to cylindrical, plicate perianths with a contracted mouth, often connate bracts and bracteoles, and 4-7 stratose capsule walls. Here we present the first comprehensive molecular phylogeny of Adelanthaceae using five markers (rbcL, psbA, trnL-trnF region, atpB-rbcL spacer, nrITS1-5.8S-ITS2) and 108 accessions from throughout the geographic range of the family. The molecular data support the separation of subfamilies Adelanthoideae and Jamesonielloideae. The Adelanthoideae include the genera Adelanthus, Pseudomarsupidium and Wettsteinia. The Jamesonielloideae include representatives of the genera Anomacaulis, Cryptochila, Cuspidatula, Jamesoniella, and Syzygiella in five main clades. The monophyly of taxa in current morphological classification schemes of Jamesonielloideae is not supported by the molecular data. Based on the outcome of the molecular phylogenetic analyses we propose to include Anomacaulis and Jamesoniella kirkii in Cuspidatula, and to place Cryptochila, Roivainenia, and Jamesoniella in the synonymy of Syzygiella. Molecular data support intercontinental ranges for several species and a range formation of Adelanthaceae by frequent short-distance dispersal, rare long-distance dispersal, extinction, and diversification. Disjunct distribution patterns within the Adelanthaceae cannot be explained by Gondwanan vicariance. (C) 2009 Elsevier Inc. All rights reserved
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
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