1,720,955 research outputs found
Vegetation changes during a 30 years period in several plant communities above the forest line (Emilian Apennines)
No full textThe study highlights the changes occurred in 10 homogeneous stands both of Vaccinium and Nardus communities of the Emilian Apennines after 30 years from the first surveys. The stands were sampled by phytosociological and phenological methods in the years 1981-1984 (Puppi, Zanotti & Speranza, 1994 - Phenological studies on Vaccinium and Nardus communities. Fitosociologia) near the mount “Corno alle Scale” (BO). In that time, the locations of the stands were exactly recorded (CRT map 1:10000) and documented by series of photos. In 2011 and 2012 the original sites were found again and the same types of surveys were repeated, with the aim to detect any change and to investigate its possible causes.
Main results are here summarized. Community’s structure has become more complex: in particular, Juniperus nana cover is significantly increased; moreover, among Vaccinium species, V.gaultheriodes is going to prevail on V. myrtillus, probably damaged by the shortening of the snow cover duration. In general, species richness is lower than 30 years ago. Many herbaceous species are rarefied or disappeared: in particular Caricetea curvulae and Nardo Callunetea species become reduced in abundance and number. On the other side, only few new species appeared ( e.g. Veratrum album, Maianthemum bifolium, etc.).
Changes in vegetation features seem to be due in part to natural dynamics (lighter grazing) and in part to climatic stress. In fact, the climate of the area has become warmer and drier (less snow and less rainfalls in winter, spring and summer) over the last 2 decades, as deduced from data of Marletto et al., 2010 (Atlante idroclimatico dell’Emilia-Romagna 1961-2008. ARPA).
Aridity periods (P/T<2), recently occurred in several summers, may be the main causal factor of the population declines in sensitive species; in fact, drought can affect the primary productivity, the reproductive success (most declining species are summer-flowering) and the survival rate
Vegetation changes during a 30 year period in several stands above the forest line (Emilian-Apennines)
No full textThe study highlights the changes occurred in several stands of Hyperico richeri-Vaccinietum communities of the high Emilian Apennines after 30 years after the first phytosociological and phenological surveys. In 2012 the same types of surveys were repeated in the original stands, with the aim to detect any change in vegetation structure as well as in species composition and behaviour. The study has pointed out significant changes in all the vegetation stands over the last 30 years. The following trends are displayed in the stands analysed: A) a general decrease of species richness per stand; B) a slight increase of the shrubs/herbs cover ratio, with a significant spreading of Juniperus communis and of Vaccinium uliginosum, sometimes coupled with a reduction of V. myrtillus cover; C) a reduction of Orophytes and of many species belonging to the classes Caricetea curvulae and Nardo Callunetea; D) a xero-thermic trend of plant communities composition (index species analysis). It is noteworthy that many of the declining species flower in the dryest and hottest period of the year (July-August). The results seems to indicate that the changes in vegetation features are due only partly to human causes (lighter grazing) and more widely to climatic stress
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
- …
