1,721,170 research outputs found
Cytogenetics and rodents twin species. Fundamental and applied aspects
No full textDobigny Gauthier, Ba Khalilou, Petter Francis. Cytogénétique et espèces jumelles de rongeurs. Aspects fondamentaux et appliqués. In: Bulletin de l'Académie Vétérinaire de France tome 154 n°3, 2001. pp. 319-330
Multidirectional chromosome painting substantiates the occurrence of extensive genomic reshuffling within Accipitriformes
No full textPrevious cross-species painting studies with probes from chicken (Gallus gallus) chromosomes 1-10 and a paint pool of nineteen microchromosomes have revealed that the drastic karyotypic reorganization in Accipitridae is due to extensive synteny disruptions and associations. However, the number of synteny association events and identities of microchromosomes involved in such synteny associations remain undefined, due to the lack of paint probes derived from individual chicken microchromosomes. Moreover, no genome-wide homology map between Accipitridae species and other avian species with atypical karyotype organization has been reported till now, and the karyotype evolution within Accipitriformes remains unclear.[br/]
To delineate the synteny-conserved segments in Accipitridae, a set of painting probes for the griffon vulture, Gyps fulvus (2n = 66) was generated from flow-sorted chromosomes. Together with previous generated probes from the stone curlew, Burhinus oedicnemus (2n = 42), a Charadriiformes species with atypical karyotype organization, we conducted multidirectional chromosome painting, including reciprocal chromosome painting between B. oedicnemus and G. fulvus and cross-species chromosome painting between B. oedicnemus and two accipitrid species (the Himalayan griffon, G. himalayensis 2n = 66, and the common buzzard, Buteo buteo, 2n = 68). In doing so, genome-wide homology maps between B. oedicnemus and three Accipitridae species were established. From there, a cladistic analysis using chromosomal characters and mapping of chromosomal changes on a consensus molecular phylogeny were conducted in order to search for cytogenetic signatures for different lineages within Accipitriformes.[br/]
Our study confirmed that the genomes of the diurnal birds of prey, especially the genomes of species in Accipitriformes excluding Cathartidae, have been extensively reshuffled when compared to other bird lineages. The chromosomal rearrangements involved include both fusions and fissions. Our chromosome painting data indicated that the Palearctic common buzzard (BBU) shared several common chromosomal rearrangements with some Old World vultures, and was found to be more closely related to other Accipitridae than to Neotropical buteonine raptors from the karyotypic perspective. Using both a chromosome-based cladistic analysis as well as by mapping of chromosomal differences onto a molecular-based phylogenetic tree, we revealed a number of potential cytogenetic signatures that support the clade of Pandionidae (PHA) + Accipitridae. In addition, our cladistic analysis using chromosomal characters appears to support the placement of osprey (PHA) in Accipitridae
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
Reproduction in urban commensal rodents: the case of Mastomys natalensis from Niamey, Niger
No full textInternational audienceMost wild Sahelian rodents display a seasonal reproduction that is usually related to rainfall, hence resources availability. Mastomys natalensis is a well-documented and major pest rodent species. In East Africa where it occurs outdoors, the species is characterized by marked population cycles. In contrast, it is mostly associated with humans in West Africa, and appears to live strictly indoors in the Sahel. Here, we have monitored the proportions of M. natalensis juveniles and sexually active adults within the city of Niamey, Niger. Our survey clearly shows that M. natalensis reproduces all year long, with no detectable seasonality. Altogether, our data confirm that reproduction may shift from seasonal to continuous when conditions are more favorable. They also suggest that the urban environment may represent an extreme habitat where resources are permanently available. From the perspective of rodent control in Niamey, our results highlight the need for a constant management policy that should be performed by public authorities
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
Inventaire et Biogéographie des rongeurs du Niger : nuisance aux cultures, implications dans certains problèmes de santé publique et vétérinaire
No full text71 pagesRapport de Coopération de Gauthier DOBIGNY (CSN Niger 1999-200)An inventory of rodent species from Niger was performed during 1999 and 2000. It covers all the major biogeographic regions (Sudan, Sahel, Sahara) and relies on 55 sites scattered all over the counrty. Unambiguous species-specific diagnoses were provided by cytotaxonomic surveys. Implications in terms of taxonomy, biodiversity, biogeography, damages to cultures and stocks as well as potential human health problems are discussed
Projet PLAY-MAD - CV malgaches
No full text<p>Curriculum vitae des trois coPI malgaches du projet PLAY-MAD, Dr Minoarisoa RAJERISON, Soanandrasana RAHELINIRINA et Mireille HARIMALALA</p>
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
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