1,720,962 research outputs found
Coding-Complete Genome Sequence of a Black Queen Cell Virus Isolate from Honey Bees (Apis mellifera) in Italy
Full text linkIn this study, we documented the complete coding genome sequence of a Black queen cell virus (BQCV) isolate from honey bees in Italy. This genome sequence illustrates a high similarity with other BQCV isolates reported worldwide and could provide insights into BQCV genome phylogeny and divergence
Occurrence, distribution, characterization of Citrus tristeza virus and its vectors in Syria
No full textCharacterization of Citrus tristeza virus isolates recovered in Syria and Apulia (southern Italy) using different molecular tools
No full textSummary. Citrus tristeza virus (CTV) is the causal agent of the most important virus disease of citrus. CTV isolates
differing in biological and molecular characteristics have been reported worldwide. Recently, CTV was detected
in Syria in citrus groves from two Governorates (Lattakia and Tartous) and several CTV outbreaks have been reported
in Apulia (southern Italy) since 2003. To molecularly characterize the CTV populations spreading in Syria
and Italy, a number of isolates from each region was selected and examined by different molecular approaches
including: Multiple Molecular Markers analysis (MMM), real time RT-(q)PCR, single strand conformation polymorphism
(SSCP) of the major coat protein (CP) gene (P25), and sequence analysis of the CP (P25), P18, P20 and
RdRp genes. SSCP analysis of CP25 yielded two distinct simple patterns among the Syrian isolates and three different
patterns in the Italian isolates. Based on MMM analysis, all Syrian CTV isolates were categorized as VT-like
genotype, whereas the Italian isolates reacted only with the markers specific for the T30 genotype. These findings
were also confirmed by RT-qPCR and by sequencing analysis of four genomic regions. The Italian isolates had
nucleotide identities which varied: from 99.5 to 99.8 for the CP gene; from 97.4% to 98.3% for the P18 gene; from
98.6% to 99.8% for the P20 and from 97.8% to 99.1% for the partial RdRp sequenced. High sequence identity was
found for all genomic regions analyzed between the Syrian isolates (from 98.9% to 99.6%). These results show that
the CTV populations spreading in Apulia and Syria are associated with different genotypes, indicating different
potential impacts on the citrus trees in the field. Since in both areas the introduction of the virus is relatively recent,
infected plants resulted to contain a single and common genotype, suggesting that CTV is spreading from the first
outbreaks by aphids or local movement of autochthonous infected plant material
A new variant of Xylella fastidiosa subspecies multiplex detected in different host plants in the recently emerged outbreak in the region of Tuscany, Italy
Full text linkThe vector-borne bacterial pathogen Xylella fastidiosa is widely distributed in the Americas; in the last decade it has emerged as a serious threat for agricultural crops, natural environment and landscape in Europe. Following the first EU outbreak in 2013 in southern Italy, associated with a severe disease in olive trees, annual mandatory surveys are now in place in the Member States, leading to the discovery of bacterial outbreaks in different countries. Among the latest findings, an outbreak has been reported in the Italian region of Tuscany, with infections identified in seven different plant species. In this work, we report the isolation and the genetic characterization of isolates associated with this newly discovered outbreak. Multilocus sequence typing approach revealed the occurrence of isolates harbouring a new sequence type, denoted ST87, genetically related to strains of subsp. multiplex, but different from the genotypes of this subspecies previously characterized in Europe. Five cultured strains were successfully recovered from four of the seven host plants, an important achievement for advancing the studies on genomics and pathogenicity of these isolates and thus assess their potential threat for European agriculture
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
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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