1,720,962 research outputs found
Evidence for fungivory in Cretaceous amber forests from Gondwana and Laurasia
No full textCretaceous amber inclusions of insect faecal pellets (also called frass) that consist of remnants of ascomycetes and basidiomycetes provide evidence for fungivory in the Mesozoic. Conidia of an anamorphic ascomycete and the possible remains of the perithecia of its teleomorph were found in Cenomanian resin from central Ethiopia. A new anamorphic genus and species, Palaeocurvularia variabilis DORFELT et A. R. SCHMIDT, is described here based on the fungal remains inside and outside the faecal pellets in the amber. Other faecal pellets consisting of remnants of polyporoid basidiomata (polyporous fungi or bracket fungi) were found in pieces of amber from the uppermost Albian in southwestern France. Pigmented skeletal hyphae, setae (spinulae) and basidiospores suggest that this insect food source pertains to the Hymenochaetales (Basidiomycota, Agaricomycetidae). While large fruiting bodies of the Homobasidiomycetes do not appear in the fossil record until the Early Cretaceous, the newly found amber inclusions from France show that these early macromycetes must have served as a habitat for fungivorous insects since the Albian.German Initiative of Excellenc
Evidence for fungivory in Cretaceous amber forests from Gondwana and Laurasia
No full textCretaceous amber inclusions of insect faecal pellets (also called frass) that consist of remnants of ascomycetes and basidiomycetes provide evidence for fungivory in the Mesozoic. Conidia of an anamorphic ascomycete and the possible remains of the perithecia of its teleomorph were found in Cenomanian resin from central Ethiopia. A new anamorphic genus and species, Palaeocurvularia variabilis DORFELT et A. R. SCHMIDT, is described here based on the fungal remains inside and outside the faecal pellets in the amber. Other faecal pellets consisting of remnants of polyporoid basidiomata (polyporous fungi or bracket fungi) were found in pieces of amber from the uppermost Albian in southwestern France. Pigmented skeletal hyphae, setae (spinulae) and basidiospores suggest that this insect food source pertains to the Hymenochaetales (Basidiomycota, Agaricomycetidae). While large fruiting bodies of the Homobasidiomycetes do not appear in the fossil record until the Early Cretaceous, the newly found amber inclusions from France show that these early macromycetes must have served as a habitat for fungivorous insects since the Albian.German Initiative of Excellenc
FIG. 4 in Taphonomy and palaeoecology of mid-Cretaceous amber-preserved microorganisms from southwestern France
No full textFIG. 4. — Resinous forest of New Caledonia as a possible analogue to the Cretaceous amber forests of southwestern France: A, resinous forest of Araucaria columnaris (J.R.Forst.) Hook. growing directly at the coast of Maré, New Caledonia. The sea appears very calm because the island is protected by a coral reef; B, resin flow on the bark of A. columnaris; C, resin dropping onto the forest floor, a possible future piece of litter amber.Published as part of Girard, Vincent, Schmidt, Alexander R., Struwe, Steffi, Perrichot, Vincent, Breton, Gérard & Néraudeau, Didier, 2009, Taphonomy and palaeoecology of mid-Cretaceous amber-preserved microorganisms from southwestern France, pp. 153-162 in Geodiversitas 31 (1) on page 159, DOI: 10.5252/g2009n1a14, http://zenodo.org/record/468815
FIG. 1 in Taphonomy and palaeoecology of mid-Cretaceous amber-preserved microorganisms from southwestern France
No full textFIG. 1. — Prokaryotes found in Archingeay-Les Nouillers (ARC) and Cadeuil (CDL) ambers: A, B, microcolonies of actinomycetes with dichotomous branching; A, ARC115.22a; B, CDL2-107; C, detail of a single microcolony of Figure 1A (ARC115.22a); D, E, actinomycetes with perpendicular branching (ARC115.13a.2); F, sheathed filaments of cyanobacteria (ARC(1-1)c); G, filaments of a possible big cyanobacterium (CDL9L-e6); H, sheathed cyanobacterium (ARC111). Scale bars: A, B, 20 μm; C-E, H, 10 μm; F, 30 μm; G, 100 μm.Published as part of Girard, Vincent, Schmidt, Alexander R., Struwe, Steffi, Perrichot, Vincent, Breton, Gérard & Néraudeau, Didier, 2009, Taphonomy and palaeoecology of mid-Cretaceous amber-preserved microorganisms from southwestern France, pp. 153-162 in Geodiversitas 31 (1) on page 156, DOI: 10.5252/g2009n1a14, http://zenodo.org/record/468815
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
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