1,720,964 research outputs found
Response of Antarctic soil fungal assemblages to experimental warming and reduction of UV radiation.
No full textAbstract This paper reports the effects of nutrient
availability, UV radiation and temperature on the taxa
composition and abundance of Antarctic soil mycobiota.
Two sites at Edmonson Point were studied: the first
was poor in nutrients, near the glacier, and the second
was close to bird nesting sites. The highest abundance of
soil fungi was recorded at the site adjacent to the bird
nesting sites. Phoma herbarum was the most abundant
taxon. Lecytophora lignicola and Ascotricha erinacea are
new records for continental Antarctica. The fungal
assemblage from the nutrient-deficient site was characterized
by a dominance-diversity curve approaching the
broken-stick model, the assemblage from the soil influenced
by birds was characterized by a lognormal distribution.
Plastic cloches were used in experiments
designed to assess differences in fungal assemblages
subjected to altered temperature and/or UV exposure.
Dominance-diversity curves and diversity values of soil
fungal mycobiota were compared in their natural condition
as compared with manipulated conditions. Under
the walled cloches, at both sites, artificial warming led to
stress on Antarctic soil fungal assemblages. In contrast,
UV protection led to a higher equilibrium in the
assemblage structure. On the basis of the results
obtained, it could be proposed that UV radiation is the
most important limiting ecological factor for soil mycobiota
in continental Antarctica
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
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
Ecology and biology of microfungi from Antarctic rocks and soils.
No full textCryptoendolithic microbial communities, living in porous sandstone rocks in the McMurdo Dry Valleys (Ross Desert) of Southern Victoria Land, Antarctica, were found within weathered pegmatite rocks in Northern Victoria Land, and the first endemic Antarctic fungal genus Friedmanniomyces endolithicus anam.- gen. and sp. nov. was isolated from this community. Selected microfungi from these communities and from soil were examined for the production of extracellular enzymes and antibiotic substances. The cryptoendolithic strain CCFEE 5001 was particularly remarkable for consistent glycosidase activity, coupled with barely detectable growth. Chitnase activity was highest in the soil microfungus Verticillium cfr. lecanii (CCFEE 5003). This strain and its purified chitinase were active on Mucor plumbeus, Cladosporium cladosporioides, Aspergillus versicolor, and Penicillium verrucosum, producing mycelial damage and cell lysis. The strain CCFEE 5020, isolated from rocks, showed antibiotic activity against Pseudomonas putida, Sarcina sp., Bacillus subtilis, and Escherichia coli, under the test conditions. Good antibiotic activity was produced in the temperature range of 5 degrees to 25 degrees C, pH 4.0, agitation at 700 rpm, and areation at 1.0 vvm, in media containing 0.5% substrate sugar, though this supported only minimal growth. The investigation of soil microfungi in contrasting sites at the BIOTAS area at Edmonson Point indicated that both the presence of bird colonies and changes in temperature and UV exposure obtained by using plastic cloches influenced species composition and density, A 'Culture Collection of Fungi from Extreme Environments' (CCFEE) has been established at the University of Tuscia, housing fungal strains from Antarctica
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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