1,720,955 research outputs found
Phylogenetic relationships of the subgenus Avaritia Fox, 1955 including Culicoides obsoletus (Diptera, Ceratopogonidae) in Italy based on internal transcribed spacer 2 ribosomal DNA sequences
No full textBiting midges of the genus Culicoides include vector species for orbiviral diseases, such as bluetongue and African horse sickness. Although the Afro-Asiatic species C. imicola is the major vector of bluetongue in the Mediterranean basin, recent outbreaks in regions where C. imicola is absent has incriminated other Culicoides, including those belonging to the Obsoletus Complex of the subgenus Avaritia Fox, 1955. The classical taxonomy of this species complex is unclear and this stimulated the molecular analysis of twenty Culicoides populations sampled from eighteen localities across Italy. Ribosomal internal transcribed spacer 2 sequences were used to characterize the intra- and interspecific variation between Italian members of the Obsoletus Complex and related species, by means of an analysis of molecular variance and phylogenetic analyses. Although morphological differentiation is often extremely difficult, the molecular analysis clearly demonstrated a high degree of divergence between most species. The study showed that at least seven species of the subgenus Avaritia occur in Italy; these are C. obsoletus, C. scoticus, C. montanus, C. dewulfi, C. imicola and two species that could not be identified with certainty, but one of which is similar to C. chiopterus. Finally, a simple polymerase chain reaction assay was developed that rapidly discriminates between four members of the Obsoletus Complex in Italy, a prerequisite for vector identification
Taxonomy of Culicoides vector complexes - unfinished business
Full text linkThe thirty species of Culicoides biting midges that play a greater or lesser role in the transmission of bluetongue (BT) disease in the pantropical regions of the world are listed. Where known, each species is assigned to its correct subgenus and species complex. In the Mediterranean region there are four species of Culicoides involved in the transmission of BT and belong in the subgenera Avaritia Fox, 1955 (three species) and Culicoides Latreille, 1809 (one species). Using both morphological and molecular second internal transcribed spacer (ITS2) sequence data, the authors reappraise the taxonomy of these four species and their congeners. A total of 56 populations of Culicoides collected from across Italy and representing 17 species (18 including the outgroup taxon C. imicola Kieffer, 1913) were analysed. The findings revealed the following: • C. imicola is the only species of the Imicola Complex (subgenus Avaritia) to occur in the Mediterranean region • in Europe the subgenera Avaritia and Culicoides (usually, but not quite correctly, equated with the C. obsoletus and C. pulicaris groups, respectively) are both polyphyletic, each comprising three or more species complexes (including a hitherto unknown complex) • about half the species studied could not be identified with certainty; furthermore, the results indicate that at least three previously described species of Palaearctic Culicoides should be resurrected from synonymy • finally, a high level of taxonomic congruence occurred between the morphological and the molecular data. One of the ‘new’ vector species, C. pulicaris, was described by the father of taxonomy, Carl Linnaeus, in 1758, but today, almost 250 years later, no monograph has appeared that treats the Culicoides fauna of the northern hemisphere as a whole. At a time when such economically important livestock diseases as BT are affecting ever larger areas of Europe, it would seem appropriate to commence the production of such a monograph to aid in the field identification of vector Culicoides. This ‘unfinished business’ might best be achieved through a collaborative network embracing all ceratopogonid specialists currently active in both the Palaearctic and Nearctic faunal realms
Phylogeny of the subgenus Culicoides and related species in Italy, inferred from internal transcribed spacer 2 ribosomal DNA sequences.
No full textBiting midges of the genus Culicoides (Diptera: Ceratopogonidae) include vectors for the economically important animal diseases, bluetongue (BT) and African horse sickness (AHS). In the Mediterranean Basin, these diseases are transmitted by four species of Culicoides: the first three belong in the subgenus Avaritia Fox and are Culicoides imicola Kieffer, Culicoides obsoletus (Meigen) and Culicoides scoticus Downes and Kettle; the fourth is Culicoides pulicaris (Linnaeus) in the subgenus Culicoides Latreille. In the Palaearctic Region, this subgenus (usually referred to as the C. pulicaris group) now includes a loose miscellany of some 50 taxa. The lack of clarity surrounding its taxonomy stimulated the present morphological and molecular study of 11 species collected in Italy. Phylogenetic analysis of nuclear ribosomal DNA internal transcribed spacer 2 (ITS2) sequence variation demonstrated a high degree of divergence. These results, combined with those from a parallel morphological study, disclosed: (1) that some previously described taxa should be resurrected from synonymy; (2) that there are new species to be described; (3) that the subgenus Culicoides (as currently employed) is a polyphyletic assemblage of four lineages - the subgenus Culicoides sensu stricto, the subgenus Silvicola Mirzaeva and Isaev, the subgenus Hoffmania Fox and the hitherto unrecognized Fagineus species complex. Each is discussed briefly (but not defined) and its constituent Palaearctic taxa listed. Strong congruence between morphological and molecular data holds promise for resolving many of the difficult taxonomic issues plaguing the accurate identification of vector Culicoides around the world
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
