1,721,558 research outputs found
Assessing sequence variation in the internal transcribed spacers of ribosomal DNA within and among members of the Contracaecum osculatum complex (Nematoda : Ascaridoidea : Anisakidae)
No full textThe anisakid nematodes of seals from different geographical origins, previously identified as Contracaecum osculatum A, C. osculatum B, C. osculatum C, C. osculatum D, C. osculatum E and C. osculatum baicalensis by multilocus enzyme electrophoresis, were characterised using a DNA approach. The first and second internal transcribed spacers (ITS-1, ITS-2) of ribosomal DNA (rDNA) were individually amplified by polymerase chain reaction (PCR) and analysed by single-strand conformation polymorphism (SSCP) and sequencing. SSCP analyses allowed the unequivocal differentiation of all taxa except C. osculatum D from C. osculatum I E. While C. osculatum D and C. osculatum E had identical ITS sequences, each of the other four taxa had distinct sequences, with interspecific differences ranging from 0.3% to 2.3%. C. osculatum C was genetically the most distinct taxon with respect to all other members of the species complex
Cryptosporidium parvum genotype IIa and Giardia duodenalis assemblage A in Mytilus galloprovincialis on sale at local food markets
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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
The increase of exotic zoonotic helminth infections: the impact of urbanization, climate change and globalization
No full textZoonotic parasitic diseases are increasingly impacting human populations due to the effects of globalization, urbanization and climate change. Here we review the recent literature on the most important helminth zoonoses, including reports of incidence and prevalence. We discuss those helminth diseases which are increasing in endemic areas and consider their geographical spread into new regions within the framework of globalization, urbanization and climate change to determine the effect these variables are having on disease incidence, transmission and the associated challenges presented for public health initiatives, including control and elimination
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
Genetic evidence for the existence of sibling species within Contracaecum rudolphii (Hartwich, 1964) and the validity of Contracaecum septentrionale (Kreis, 1955) (Nematoda : Anisakidae)
No full textSpecimens of Contracaecum rudolphii sensu lato (s.l.) (Nematoda: Anisakidae) from Phalacrocorax carbo sinensis from northeastern and central Italy were characterised genetically and compared with those from Phalacrocorax aristotelis from Galician coasts, Spain (identified as C. rudolphii A by multilocus enzyme electrophoresis) and with specimens of C. septentrionale from Alca torda from the Galician coasts, Spain. The first (ITS-1) and second (ITS-2) internal transcribed spacers (ITS) of ribosomal DNA (rDNA) were amplified by polymerase chain reaction (PCR) from individual nematodes and the amplicons subjected to single-strand conformation polymorphism (SSCP) analysis and/or sequencing. For each ITS region, C. septentrionale specimens were distinct from those of C. rudolphii (s.l.) and C. rudolphii A based on SSCP profiles and ITS sequences. Some specimens of C. rudolphii (s.l.) had the same SSCP profiles and ITS sequences as C. rudolphii A, whereas the others had distinct SSCP profiles and ITS sequences and were suggested to represent C. rudolphii B based on host and geographical origins and genetic similarity to C. rudolphii A. While no length or nucleotide variation in the ITS-1 and ITS-2 sequences was detected within each taxon, nucleotide differences of 1.8-5.5% (ITS-1) and 5.1-12.2% (ITS-2) were detected among them. The results support the hypothesis that C. rudolphii represents a complex of at least two sibling species and provide support for the validity of C. septentrionale as a separate species. The definition of genetic markers in the ITS rDNA provides opportunities for investigating the life cycles, transmission patterns and ecology of the anisakid nematodes studied herein
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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