1,720,971 research outputs found
The occurrence of Thelohania contejeani Henneguy, a microsporidian parasite of the crayfish Austropotamobius pallipes (Lereboullet), in Liguria Region (NW Italy)
No full textThe presence of the microsporidian parasite Thelohania contejeani Henneguy, responsible for porcelain disease (thelohaniasis), is reported in several crayfish populations inhabiting the Liguria Region. The infestation rate of this parasite was low, ranging from 0.17 to 3.7 per cent, and in two water courses it remained constant through years. However, we recommend performing periodically sanitary controls on the infected populations of Liguria and extending such controls to other populations not yet monitored. In fact, the virulence of the pathogens could increase owing to environmental stresses such as pollution, increase in crayfish density, paucity of food etc. We underline the importance, already suggested by other authors, of creating a central disease register to check the diffusion of the pathogens and facilitate the adoption of countermeasures
Incidenza dell’autotomia nel gambero di rio, Austropotamobius pallipes (Lereboullet), in Liguria (Italia nord occidentale)
No full text
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
Maternal care and defence of young by the plethodontid salamander Speleomantes strinatii (Aellen, 1951)
No full textEgg brooding females of the North-west Italian Cave Salamander Speleomantes strinatii display a complex array of parental behaviours. Recently, prolonged skin contacts between mother and young were documented by means of infra-red video recording, up to 40 days after
hatching. In this study the behaviour of two females attending their young in presence of a po-tential predator was experimentally tested. About seven days after hatching, two adult males of S. strinatii were introduced inside the terrarium, where two females (A and B) were both attending
eight young. In one case, female A approached female B and her young, but was repelled away.
The approaching male always elicited an aggressive behaviour of females that repelled the intruder by head pushes and bites. This behaviour, similar to the one displayed during egg brooding, is the first evidence of active defence of young in terrestrial salamanders
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
Optimizing monitoring schemes to detect trends in abundance over broad scales
Full text linkMeasuring population changes and trends is essential to identify threatened species, and is requested by several environmental regulations (e.g. European Habitat Directive). However, obtaining this information for small and cryptic animals is challenging, and requires complex, broad-scale monitoring schemes. How should we allocate the limited resources available for monitoring, to maximize the probability of detecting declines? The analysis of simulated data can help to identify the performance of monitoring scenarios across species with different features. We simulated data of populations with a wide range of abundance, detection probability and rate of decline, and tested under which circumstances open-population N-mixture models can successfully detect the decline of populations. We tested multiple monitoring strategies, to identify the ones having the highest probability of detecting declines. If 30 sites are surveyed, strong declines (≥30%) can be successfully spotted for nearly all the simulated species, except the species with lowest abundance and detection probability. Weaker declines are successfully identified only in species that are easy to detect and have high abundance. Increasing the number of sites quickly increases model power, but hundreds of sites would require monitoring to measure trends of the least detectable species. For most of species, performance of monitoring was improved by: surveying many sites with a few replicates per site; surveying many small sites instead of a few large sites; combining data from sites monitored for multiple species. Our findings show that one single monitoring approach cannot be appropriate for all the species, and that surveying efforts should be modulated across them, according to their detection probabilities and abundances. We provide quantitative values on how the number of surveys and the number of sites to be surveyed can be assigned to different species, and emphasize the need of planning to maximize the performance of monitoring
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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