1,720,981 research outputs found
Local environment prevails over population variations in growth-climate relationships of Pinus pinaster provenances
No full textIn view of the projected decrease in precipitation and increase in temperature, a better understanding on growthclimate responses in different populations of tree species is needed to improve and enhance the conservation and management strategies for major forest tree species. In this study, we assessed differences in growth traits (i.e., stem diameter, tree height, and stem radial growth) and analysed climate-growth relationships in five provenances of maritime pine (Pinus pinaster Ait.) grown in four replicated common gardens in Sardinia (Italy). Stem radial growth increased under a positive water balance in late winter and early spring. Conversely, high temperature and low precipitation in summer had a negative impact on stem radial growth. At age 40, none of the considered provenances (Portugal, Corsica, Tuscany, Sardinia-Telti, Sardinia-Limbara) showed a substantial advantage in more than one common garden site for tree height and stem diameter. Nevertheless, differences were found among common garden sites in terms of dendrometric parameters, stem radial growth, and growthclimate responses (including sensitivity to summer drought), suggesting a greater site dependent over tree growth. Although in juvenile stages the Portuguese provenance (in particular) showed greater growth than the Sardinian ones, this study showed that, with tree age, the differences among the five provenances tends to narrow. Therefore, irrespective of the seed source, tree growth patterns and growth-climate responses were similar at age 40. This result can be important for implementing forest management strategies to balance adaptation and mitigation potential of maritime pine plantations in harsh environmental conditions
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
Species interactions in pure and mixed-species stands of silver fir and European beech in Mediterranean mountains
Full text linkInteractions between tree species determine the dynamics of forest communities. Spatial and temporal changes in resource availability, variation in species composition and spatial distribution of trees may alter competitive interactions between species and, therefore, affect tree growth and forest productivity. In this study, we analyzed the intra and inter-specific interactions between European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.) in southern Italy (Molise and Calabria regions), and how these interactions affect basal area increments in mixed-species and pure stands. Results showed that intra-specific interactions have a negative effect on the basal area increment, both in pure and mixed-species stands of Molise and Calabria. Basal area increment was higher influenced by intra-specific interactions in pure stands than in mixed-species stands. Silver fir in Molise showed higher basal area increment in mixed-species stand, probably in relation with stand structure and space occupation that resulted in less competition between individual trees. European beech showed high values of intra-specific interactions in pure stands, likely related to the low self-tolerance of this species and to the spatial arrangement of trees, due to canopy closure. The absence of inter-specific interactions in mixed-species stands could be explained by the sub-dominant position of European beech, which may have limited the benefit derived from niche separation and complementarity for silver fir
Interannual radial growth sensitivity to climatic variations and extreme events in mixed-species and pure forest stands of silver fir and European beech in the Italian Peninsula
No full textClimate change is increasingly favouring the occurrence of extreme weather events, affecting species distribution and tree growth. It has been proposed that mixed forests are more resistant to drought spells and heat waves than corresponding monocultures. We sampled tree cores in nine plots along a latitudinal gradient of the Italian Peninsula (Trentino, Molise and Calabria). The objective of the study was to identify radial growth responses in mixed-species and pure plots of European beech and silver fir to climate dynamics and extreme events. Pointer years, as well as correlation and response functions, were used to analyse the climate–growth relationships in mixed-species and pure plots. Climate–growth relationships showed differences between mixed-species and pure plots only at the regional level. In particular, Trentino differed from Molise and Calabria, when considering maximum temperatures. In Trentino, winter (for silver fir) and summer (for both species) temperatures had a less negative impact on the radial growth of trees, in comparison with Molise and Calabria. Nevertheless, correlations between the radial growth and drought indices, and the principal component analysis, showed that plots were relatively unresponsive to summer drought. These results can be important for the implementation of operational techniques that increase the adaptation of silver fir and European beech to climate change, as well as for assisted migratio
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