1,720,954 research outputs found
How mowing restores montane Mediterranean grasslands following cessation of traditional livestock grazing
Full text linkTraditional land-use cessation allows the spread of invasive tall-grass species and thus leads to a reduction in grassland biodiversity. We hypothesized that long-term multi-year mowing of invaded grassland fosters the recovery of its taxonomic diversity and functional composition by reducing the dominance of the tall grass species Brachypodium rupestre, and that this change increases the pasture feed value. In 2010, we fenced part of a grassland, abandoned for about 30 years, invaded by Brachypodium rupestre (1 ha) in the central Apennine ridge (1,000–1,300 m a.s.l.), and cut it twice a year for six years; another area (1 ha) was fenced and left unmown. Before the experiment started, we recorded species cover in 30 random sampling units (0.5 × 0.5 m) in the experimental area and in the unmown area. The sampling was repeated for the experimental area, every year for six years, except 2013, while it was done for the unmown area only at the end of the six years. We investigated the effect of the reduction of Brachypodium rupestre over time on taxonomic diversity indices, functional traits and pastoral value, using species accumulation curves and generalized linear mixed-effect modelling. Twice-yearly mowing was effective in reducing the abundance of B. rupestre (mean cover 50.7 ± 19.8 % Standard deviation to 9.0 ± 7.2 %), and in increasing significantly species richness (16.6 ± 3.0–26.8 ± 3.2), exponential Shannon (8.8 ± 2.8–14.4 ± 2.7), but not Shannon evenness (0.53 ± 0.1 to 0.54 ± 0.1). At the end of the treatment quite stable richness and diversity values were reached. Reduction of B. rupestre cover increased the pastoral value of the system (39 ± 12 %–64 ± 8 % of pabular species relative cover) and promoted the presence of species without vegetative propagation (17.8 ± 12.3–28.2 ± 10.9), with pleiocorms (25.4 ± 14.3–49.6 ± 17.9), rosettes (5.6 ± 5.6–16.6 ± 12.7) and hemirosettes (32.1 ± 15.8–47.7 ± 13.6), but caused a decrease in species whose clonal growth organs have prevalent vertical spread (123.9 ± 25.7–97.0 ± 23.3), reptant (60.3 ± 20.9–20.2 ± 10.4), and late flowering species (67.4 ± 19.9–46.3 ± 17.2). The decrease of B. rupestre and the increase in mowing frequency reduced the abundance of species with clonal growth organs with prevalent horizontal spread (66.0 ± 19.5–17.9 ± 10.7), caespitose species (96.7 ± 20.9–43.6 ± 21.9), and grasses (94.0 ± 19.5–43.3 ± 22.0). Recurrent twice-yearly mowing seems to be appropriate in the restoration of sub-Mediterranean grasslands invaded by competitive species, facilitating the re-introduction of traditional grazing
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
Species trait syndrome drives the leaves’ functional variations of dominant grasses to modifications in summer water supply
No full textClimate change models predict a strong reduction of average precipitation, especially of the summer rainfall, and an increase in intensity and frequency of drought events in the Mediterranean region. The research aim was to understand how four dominant grass species (Arrhenatherum elatius, Cynosurus cristatus, Elymus repens, and Lolium perenne) in sub-Mediterranean meadows (central Apennines, Italy) modulate their resource acquisition and conservation strategies to short-term variation of the pattern of summer water supply. During summer 2016, using a randomized block design, we tested the effect of three patterns of summer water supply, differing in water amount and watering frequency, on leaf area, leaf dry mass, specific leaf area (SLA), leaf senescence, and plant height. Our results showed that dominant grass species can modulate their strategies to variation of the pattern of summer water supply, but the response of leaf traits and plant height is mediated by the set of functional characteristics of the species. E. repens and A. elatius, with summer green leaves, lower SLA, later flowering period, and deeper roots, were less influenced by changes in water amount. C. cristatus and L. perenne, which display acquisitive strategies (persistent leaves, higher SLA values), earlier flowering, and shallower roots were more influenced by changes in the pattern of summer water supply. Our results suggest that a short-term decrease in water availability might affect primarily species with trait syndromes less adapted to face summer drought
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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