1,721,160 research outputs found
Data from: Extra food provisioning does not affect behavioral lateralization in nestling lesser kestrels
No full textThis dataset includes the data on lesser kestrel nestlings analyzed in the published article: Camilla Soravia, Angelo Bisazza, Jacopo G Cecere, Diego Rubolini (2022). Extra
food provisioning does not affect behavioral lateralization in
nestling lesser kestrels, Current Zoology; zoac021, https://doi.org/10.1093/cz/zoac021</div
Birds and powerlines in Italy : an assessment
Get PDFPowerlines may pose severe threats to bird populations. We assessed the significance of powerlines as a source of avian mortality within the Italian electric transmission and distribution system. We reviewed data from 11 mortality censuses and compiled a list of species that were found among powerline victims in Italy, based on over 1,300 reported individual casualties. Overall, 95 species of birds were reported among powerline victims (19% of Italy's total species). The number of recorded species was compared with the number of species in the Italian list, after grouping species based on morphology and ecology. Some groups (e.g. raptors, herons, storks and allies) were highly affected, while others (e.g. passerines and allies) appeared to be poorly represented among species involved in powerline accidents. Furthermore, we evaluated the validity of a published discriminant model for the classification of bird species as collision or electrocution victims according to body measurements. The application of the available model classified 54.7-73.5 % of Italian species correctly (depending on the species included), compared with 88.6% of the original dataset. Two new discriminant models based on Italian powerline casualties classified 80.9-81.1% of species correctly. This approach can be a useful tool in assessing collision and electrocution risk for species in different geographical areas. While we recognize the need for a general preventive approach for reducing the bird-powerline conflict, our review highlights once more the importance of local situations, where powerlines may have a strong impact on avian communities
Immune response covaries with corticosterone plasma levels under experimentally stressful conditions in nestling barn swallows (Hirundo rustica)
No full textTraits related to fitness are often pleiotropically linked or otherwise constrained in their expression. Organisms therefore trade between fitness components such as number and viability of their offspring. The physiological mechanisms mediating such trade-offs, however, have been poorly investigated. We manipulated brood size and satiation of nestling barn swallows, Hirundo rustica, to simulate the effect of two kinds of natural stresses, i.e., long-term intense competition in a large brood and acute food deprivation, and we measured their effect on body condition, T cell-mediated immune response, and corticosterone, the main hormone mediating the adrenocortical stress-response. Brood enlargement increased corticosterone levels compared with those for brood reduction, and brood enlargement depressed immune response, body mass, and condition. Corticosterone levels markedly increased after food deprivation. Immune response negatively covaried with corticosterone levels measured after long-term stress. Hence, living in a crowded nest and with food deprivation elicited a stress response mediated by corticosterone, and depressed an important component of offspring fitness such as T cell-mediated immunity. The negative covariation between circulating corticosterone and immunity suggests that the trade-off between offspring number and quality is mediated by variation in plasma levels of corticosterone, which has immunosuppressive effects
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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