1,720,974 research outputs found
Effects of global climate change on terrestrial small mammals communities in Italy.
No full textIn the framework of climate change, it has been predicted that the Mediterranean Basin will experience the greatest loss of biodiversity, because it will be heavily affected by several drivers of change. In particular, Italy is an important geographical area because it represents a key hotspot of biodiversity. The aim of this study was to evaluate the effects of global climate chan-e on terrestrial small mammals (Rodents and Soricomorphs) in Italy. Barn owl (Tyto alba) pellet analysis was applied to study the temporal variations of microteriocoenoses structure. We revisited 21 roosting, sites which had been previously studied by other authors and we carried out a similar study in order to analyse possible changes in small mammal communities. Analyses covered a period of about 30 years and the gap between the first and second sampling ranges from I I to 33 years. Collecting localities were grouped according to the Bioclimatic Map of Italy. Several ecological indexes were applied and their changes through time were analysed for each Bioclimatic Region. Results show a significant increase in thermoxerophilic species in the last thirty years, particularly in the Mediterranean Region. This observed rise is likely due to global and local warming. In fact, higher temperatures, lower precipitation and increasing xerothermic conditions could have facilitated the spread of thermoxerophilic species. The persistence of such a trend could lead to a series of serious ecological consequences in the future, including a possible reduction in biodiversity
Les communautés de petits mammifères de trois "fiumare" de la Calabre (Italie du Sud).
No full textLes communautés de petits Mammifères (Insectivora, Rodentia) de trois «fiumare» du nord-est de la Calabre ont été analysées. Des transects de lignes de pièges d'interception ont été disposés sur les pentes, les bords et la grève dans la partie inférieure de trois «fiumare» pour contrôler un éventuel effet-barrière causé par le biotope de la «fiumara» sur les populations de petits Mammifères. 33 stations, Situées à une altitude comprise entre 100 et 300 m, ont été suivies. 379 individus appartenant à 7 espèces différentes: 3 Insectivores (Suncus etruscus, Crocidura suaveolens, C. leucodon) et 4 Rongeurs (Muscardinus avellanarius, Apodemus sylvaticus, A. flavicollis, Mus domesticus)'ont eté capturés; 90 % des micromammifères capturés appartiennent à trois espèces seulement: S. etruscus, A. sylvaticus (qui est l'espèce nettement dominante) et M. domesticus. Très peu d'animaux ont été trouvés dans la grève de la «fiumara». Il s'agit surtout de Rongeurs, qui vraisemblablement proviennent des berges voisines. Cela indique que la «fiumara» peut constituer plutôt qu'une barrière, un important facteur limitant pour la dispersion des micromammifères
New European southern distribution limit of Neomys fodiens (Pennant, 1771) (Insectivora, Soricidae).
No full textMitochondrial DNA reveals different phylogeographic structures in the water shrews Neomys anomalus and N. fodiens (Insectivora: Soricidae) in Europe
No full textWe studied the intraspecific genetic variation of 17 Neomys anomalus (Cabrera, 1907) (eight localities) and 24 Neomys fodiens (Pennant, 1771) (nine localities) in Europe. As molecular marker, we used the sequences of the mtDNA gene for cytochrome b (1140 bp from 24 specimens; 272 bp from 15 specimens). The phylogenetic analysis of N. fodiens shows slight divergence among haplotypes, with only one supported clade including two geographically distant haplotypes from Calabria (southern Italy) and Pyrenees (France); these haplotypes diverge from the others by 2.9% and 2.1%, respectively. In N. anomalus, one haplotype from Spain is very different, diverging from all others by 8-10% of the sequence. This level of divergence is similar to that found between N. anomalus and another species, Neomys teres. There are two other supported clades in N. anomalus, an Italian subclade and an eastern subclade comprising haplotypes from Turkey and Slovenia. Moreover, we found a different genetic structure between the two species with greater divergence in N. anomalus than in N. fodiens. The phylogeographic patterns are discussed in a temporal framework and considering the different ecological characteristics of these two species. © 2007 The Authors
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
Mitochondrial DNA reveals hidden diversity and an ancestral lineage of the bank vole in the Italian peninsula
No full textThe Italian Peninsula was one of the main refugia in southern Europe during the climatic oscillations of the Pleistocene, and was considered a 'hotspot' of biodiversity. A number of phylogeographic analyses identified highly divergent lineages in Italy that apparently did not contribute to the post-glacial re-colonization of Europe, supporting the existence of refugia within refugia in the southern-most part of Italy. For the bank vole Myodes glareolus, genetic analyses highlighted a low variability for this species on the Italian peninsula, suggesting that cryptic refugia of central Europe were the main source of postglacial re-colonization in Europe. In this work, we analysed the mtDNA phylogeography of M. glareolus with a special emphasis on the Italian refugium. We extended previous analyses by including new sequences from a wider range of samples across the Italian peninsula. Our results suggest a high mitochondrial diversity of the bank vole in Italy and support the existence of an ancient and deeply divergent population in the Calabria region. This population did not participate to the recent re-colonization of Italy while we highlight the possible occurrence of multiple and more recent colonization events between Europe and Italy. The phylogeographic pattern observed in Italy appears compatible with refugia-within-refugia scenario. © 2011 The Zoological Society of London
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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