1,720,958 research outputs found
Seed dormancy and germination ecology of Lamyropsis microcephala: a mountain endemic species of Sardinia (Italy)
No full textLamyropsis microcephala only occurs in a very restricted area in the Gennargentu massif (CE-Sardinia, Italy)
at 1450-1700 m a.s.l. This rare species has been inserted in the International Union for Conservation of Nature
(IUCN) Red Lists under Critically Endangered. In this study, the effect of a pre-chilling period (90 days at 5°C)
on germination was investigated as well as the ability of this species to form a soil seed bank. L. microcephala
seeds exhibited type 2 non-deep physiological dormancy. Pre-chilling increased the final germination percentages,
the germination speed and the temperature range at which high levels of germination were observed. The high
optimal germination temperatures (ca. 70% germination at 30°C) demonstrate that this species is well adapted
to a temperate climate and the lack of a persistent soil seed bank represents a rarity trait that likely exacerbates
the threats to the survival of this species
Adaptation to habitat in Aquilegia species endemic to Sardinia (Italy): seed dispersal, germination and persistence in the soil
No full textThe autecology of the Sardinian endemics Aquilegia barbaricina Arrigoni et Nardi and A. nugorensis Arrigoni et Nardi were
investigated. Peaks of anthesis and seed dispersal were recorded for five populations occurring in two distinct habitats, one
riparian and one rupicolous. Germination tests were carried out on seed lots belonging to each population by sowing seeds at
10, 15, 20, 25 and 25/158C. In addition, seeds were incubated for 2 months at either 258C (summer), 58C (winter) or 258C
for 2 months plus 2 months at 58C (summer followed by winter–SW), and then moved to the germination temperatures.
Embryo measurements were taken during pre-treatments and germination. Experimental seed burials were carried out for
two populations of each species. Both species dispersed in summer. The population of A. nugorensis occurring on rocky
outcrops differed in phenology from both the other A. nugorensis population from riparian vegetation and from A. barbaricina.
Both species showed morphophysiological seed dormancy, with550% germination under laboratory conditions. All riparian
populations germinated only after the SW pre-treatment, while the rupicolous population germinated at 258C, without any
pre-treatment. Low germination percentages were observed in the experimental seed burials, suggesting the ability for both
species to form a persistent soil seed bank
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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