1,720,960 research outputs found
Short-term effects of fire on butterflies community (Lepidoptera, Rhopalocera) in mediterrean maquis.
No full textShort-term effects of fire on Papilionoidea (Lepidoptera) communities: a pilot study in Mediterranean maquis shrubland
No full textIn the Mediterranean landscapefires are common, sometimes arising due to human activity. Fire influences the amount of
sunlight that reaches the ground, thus affecting the diversity and distribution of animal and plant species. In this study, we
analysed the effect offire on butterfly diversity at the Site of Community Importance (SCI)“Monti di Lauro”(IT8040013)
in southern Italy (Campania). The area covers 7040 ha and is mainly characterised by Mediterranean maquis and woody
vegetation. We compared theflight activity of butterflies before and after a fire incident in October 2008. Weekly transects
were made from April to September in 2008 and 2009. From the transect data, we calculated several diversity indices. We
surveyed 55 species and 5052 individuals (2008: 43 species, 1764 individuals; 2009: 49 species, 3288 individuals). Inter-year
comparisons showed that richness was significantly lower in 2008 than in 2009, as well as the abundance; the evenness index
was significantly higher in 2008 than in 2009. Intra-year comparisons beforefire (2008) showed significant differences
among months in all indices analysed, whereas afterfire (2009), only evenness differed significantly. Our results show that
afterfire in the Mediterranean maquis, a rapid change in butterfly community structure occurred, increasing both species
and individual abundance. Nevertheless, a lower evenness indicates a less balanced butterfly community afterfire. Notably,
Melanargia arge, a protected species by the Habitats Directive, was not observed following the fir
Direct and indirect anthropogenic disturbances: wild boar and landfill effects on Papilionoidea (Lepidoptera) in SCI “Monte Licosa e dintorni”
No full text
On the design of origami structures with a continuum of equilibrium shapes
No full textHere we focus on the problem of how to fold/deploy an origami structure. We consider origami tessellations which can pass from one shape to another through a continuum of equilibrium configurations. Among different tessellations, we choose the one invented by Ron Resch. This tessellation features only triangular panels, a property that allows us to simplify the model, and that gives the structure higher stiffness with respect to other types of tessellations. We present two distinct procedures for changing the shape of an origami. In the first one, a certain number of bars is added to the system, to make the structure isostatic and to control, by varying their length, the change of shape. In the second procedure, length changes are assigned only to a minimum number of control elements, while the remaining length changes are determined by imposing a sufficient and minimal number of constraints. Such constraints can impose symmetry conditions and/or particular nodal trajectories. We found that often it is not possible to arbitrarily control all degrees of freedom of Resch's origami structures, since a halt in the folding/deployment path can occur, with the structure locked in a singular configuration. This problem is sidestepped by assigning fewer kinematic constraints and by using the pseudo-inverse solution of the system of kinematic-compatibility equations. Our approach is general enough to be applied to origami structures at different scales, and of different patterns
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
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