1,720,955 research outputs found
Initial constraints in seedling dynamics of Juniperus macrocarpa Sm.
No full textThe micro-forests dominated by Juniperus
macrocarpa inhabiting coastal dunes in the Mediterranean
Basin are European priority habitats. Their
conservation is hindered by both anthropic and natural
causes, although the regeneration problems for J.
macrocarpa are still poorly understood. In this study,
several factors influencing emergence and mortality of
J. macrocarpa seedlings were investigated. For this
purpose, permanent plots were placed in coastal dunes
of Sardinia (Italy) and periodically monitored to
record seedling parameters (emergence, survival and
growth), as well as several biotic and abiotic variables
(solar radiation, tree cover, herbaceous plus scrub
cover, number of female cones on the soil and number
of herbivory traces). Linear mixed models were fitted
to test the effects of several types of explanatory
variables on seedling dynamics. A total of 536
seedlings were marked, most of which emerged in
winter. The microhabitat was the most important
factor in models explaining emergence, with the
number of emerged seedlings decreasing with solar
radiation. Survival was very low, reaching the highest
mortality percentage in the first summer. Herbivory
and location in open interspaces had significant
negative effects on seedling survival. In conclusion,
the recruitment of J. macrocarpa is highly limited in
the initial life cycle phases, with microhabitat and
herbivory constraints influencing seedling dynamics.
The identification of critical stages in the recruitment
process of J. macrocarpa, together with factors
influencing them, suggests some implication for
management as well the hypotheses for future studies
about conservation and recovery of the J. macrocarpa
habitat
Inter-and intraspecific morphometric variability in Juniperus L. seeds (Cupressaceae)
No full textIn this study, a statistical classifier for Mediterranean taxa of Juniperus, based on 98 seed morphometric parameters, was tested at interspecific, specific and intraspecific levels. Ripe cones of 10 taxa were collected in different regions of the Mediterranean Basin to compare and discuss their taxonomic treatments according to two different sources. High percentages of correct identification were reached for both taxonomic treatments at the specific and intraspecific level and from the comparison among taxa of the J. oxycedrus, J. communis and J. phoenicea complexes. Moreover, ripe cones of J. macrocarpa were collected from four Sardinian populations, in two seasons, and from plant and soil, in order to analyse inter-population, seasonal and source variability in seed morphology. This statistical classifier discriminated J. macrocarpa seeds collected in spring more accurately than those collected in autumn, but it failed to distinguish between the seeds collected from plants and soil, or between those collected from different populations of the same geographic region
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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