1,720,963 research outputs found
Metacercariae of Ascocotyle sp. and Heterophyes sp. (Trematoda: Heterophyidae) in grey mullets (Osteichthyes: Mugilidae) from Sardinia brackish waters (western Mediterranean Sea).
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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
Parasites of the Lessepsian sprinter Fistularia commersonii (Osteichthyes: Fistulariidae): an update after 15 years since its arrival in the Mediterranean Sea
No full textFistularia commersonii is a Lessepsian sprinter recorded for the first time in the eastern Mediterranean Sea (Israel) in 2000. Within a few years, this species reached the central Mediterranean (2004, Sicily) and, subsequently, the western Basin (2007, Iberian Peninsula). Merella et al. (2007) and Pais et al. (2007) described its parasites in the Mediterranean Sea from one fish caught off the Sardinian coast and six from North Africa, finding native generalist species, but also two Indo-Pacific digeneans: Allolepidapedon fistulariae and Neoallepidapedon hawaiiense. From 2007 to 2014, the capture of 24 specimens of F. commersonii in Sardinian waters allowed to add information about its parasites in the Mediterranean, and to evaluate their dynamics throughout the host migration path. Twenty parasite species/taxa were found, adding 13 taxa to the former Mediterranean list. The results confirmed earlier data: A. fistulariae, Nybelinia africana and Phyllobothriidae (Cestoda), Hysterothylacium spp. (Nematoda) and Gnathiidae (Crustacea) were among the most frequent parasites (P>15%); besides, two other taxa showed prevalence higher than 15%: Pseudogrillotia sp. (Cestoda) and Breizacanthus cf. ligur (Acanthocephala). Neoallepidapedon hawaiiense, previously recorded in North Africa, was not found in the present specimens. The results suggest that a non-indigenous species is not always subjected to the release from its natural enemies. Actually, the parasite fauna of F. commersonii increased throughout the host migration path, acquiring new generalist species, but also conserving the natural parasite A. fistulariae, that seemingly has been able to close its life cycle in the Mediterranean Sea
Parasites and Lessepsian migration of Fistularia commersonii (Osteichthyes, Fistulariidae): shadows and light on the enemy release hypothesis
No full textAccording to the enemy release hypothesis, one of the reasons for the successful establishment of non-indigenous species in a new habitat is the libera- tion from natural enemies, and among them the parasites. The rapid spread of the Red Sea/Indo-Pacific fish Fistu- laria commersonii in the Mediterranean Sea, which in just 7 years (2000–2007) invaded nearly all of the basin, gives an opportunity to study the dynamics of the host and its parasites in its recently invaded range. Informa- tion on the parasites of this fish in its original habitat is quite scarce. The present study describes the metazoan parasites of 40 specimens of F. commersonii (total length range 73–107 cm) caught in the Mediterranean Sea (Sar- dinia, Tunisia, Libya) from 2005 to 2015. The parasite fauna of this migrant in the recently invaded range is mainly a combination of generalist juvenile/larval spe- cies (probably acquired in the new habitat) with some of its adult natural parasites (probably co-introduced during migration). The results indicate that a non-indigenous species is not always released from its natural parasite and that its success is not simply associated with such liberation. Actually, the parasite fauna of F. commer- sonii increased along its migration path, acquiring new generalist species, but also conserving a subset of natu- ral parasites. These data suggest caution in the uncritical acceptance of the enemy release hypothesis, because the different phases of the invasion process and establish- ment of a non-indigenous species appear to be related to a combination of ecological, physiological and behav- ioural factors
Primi risultati sulla presenza e la caratterizzazione biomolecolare di nematodi anisakidi in specie ittiche marine pescate nel Nord Sardegna.
No full textFirst contribution to the knowledge of the epidemiology and molecular characterization of Anisakis spp. in commercial fish caught off northern Sardinia.
No full textDispelling 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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