Search results for "election"
showing 10 items of 2159 documents
Overestimation of the strength of size-assortative pairing in taxa with cryptic diversity: a case of Simpson's paradox.
2015
5 pages; International audience; Size-assortative pairing is one of the most common pairing patterns observed in nature and it probably occurs in many taxa with cryptic diversity. Observed patterns of size-assortative pairing in natural populations may thus be influenced by the co-occurrence of noninterbreeding cryptic groups of individuals living in sympatry. To quantify this potential bias, we sampled amphipods from the Gammarus pulex/Gammarus fossarum crustacean species complex in rivers containing two sympatric and morphologically cryptic groups, i.e. molecular operational taxonomic units (MOTUs). Within each river, MOTUs did not interbreed and differed in mean body size. We measured th…
Ecological differentiation and reproductive isolation of two closely related sympatric species of Oenanthe (Apiaceae)
2010
Oenanthe conioides is a lower Elbe endemic plant species growing in the freshwater tidal zone around Hamburg (Germany). Its closest relative Oenanthe aquatica is widely distributed in Eurasia and grows in calm and shallow freshwater. The two species differ in habitat requirements but are otherwise sympatrically distributed, suggesting that ecological divergence has to be maintained in the face of gene flow. In the present study, we investigated ecological differentiation and reproductive isolation in these two species. An amplified fragment length polymorphism analysis found clear genetic differentiation between the two species implying reproductive isolation. A reciprocal transplantation e…
What do we need to know about speciation?
2011
Speciation has been a major focus of evolutionary biology research in recent years, with many important advances. However, some of the traditional organising principles of the subject area no longer provide a satisfactory framework, such as the classification of speciation mechanisms by geographical context into allopatric, parapatric and sympatry classes. Therefore, we have asked where speciation research should be directed in the coming years. Here, we present a distillation of questions about the mechanisms of speciation, the genetic basis of speciation and the relationship between speciation and diversity. Our list of topics is not exhaustive; rather we aim to promote discussion on rese…
Selection on size and secondary sexual characters of the damselfly Calopteryx splendens when sympatric with the congener Calopteryx virgo
2011
Male mating success is often determined by body size or secondary sexual characters because of female mate choice or competition for females. In addition to intraspecific interactions, interspecific interactions may interfere with intraspecific selection. In this study, we investigated sexual selection on size and sexual characters of male banded demoiselle ( Calopteryx splendens (Harris, 1780)) in wild populations sympatric with the beautiful demoiselle ( Calopteryx virgo (L., 1758)). As secondary sexual characters, male C. splendens have pigmented wing spots whose size appears to be under positive selection. Male C. virgo resemble male C. splendens that have the largest wing spots, leadi…
Les élections professionnelles en France
2019
International audience; Les élections professionnelles offrent des informations irremplaçables sur la société française au travail (Andolfatto 1992). Pourtant, contrairement aux élections politiques, ces scrutins n’ont pas fait l’objet d’un suivi systématique et leurs résultats détaillés sont difficilement accessibles pour les chercheurs.C’est pourquoi nous mettons en ligne un dossier contenant 55 fichiers de données concernant les élections professionnelles en France dans le secteur à convention collective (par opposition aux trois fonctions publiques : Etat, collectivités territoriales, hôpitaux) – soit 9,1 d’électeurs - pour la période 2009-2016. Après avoir présenté ces données, nous al…
Syndicalisme français : quel nouveau modèle ?
2019
International audience; Les événements spectaculaires qui ont secoué la France à partir de novembre 2018 ont révélé encore une fois la relation difficile qu’entretient une proportion importante de Français avec leurs dirigeants. Ce fut une nouvelle illustration d'un paradoxe hexagonal : peu de pays, et peut-être aucun, n’a autant de "représentants" et pourtant beaucoup de Français se sentent mal ou pas représentés. Du point de vue politique, au plan national, il y a trois assemblées, nombreuses et bien dotées (Assemblée nationale, Sénat, Conseil économique, social et environnemental) , et on retrouve des assemblées – également nombreuses - au niveau régional, départemental et communal . De …
L’état du syndicalisme en France
2016
International audience
Le chaudron social de la SNCF
2018
International audience; Dans les représentations collectives, la SNCF demeure un bastion syndical, voire l’un de ces derniers bastions compte tenu de la désyndicalisation – assez générale en France et en Europe –depuis une trentaine d’années. Elle est aussi le foyer de grèves récurrentes qui polarisent l’actualité et traduisent une approche des relations sociales en termes de luttes semblant elles aussi, pour de bonnes ou de mauvaises raisons, appartenir à un autre temps. Tout cela confère à l’entreprise ferroviaire une certaine coloration, une image de chaudron social régulièrement en ébullition, qui a fini par supplanter une vision plus moderniste ou technologique de la SNCF. Cette représ…
Urban monitoring using multi-temporal SAR and multi-spectral data
2006
In some key operational domains, the joint use of synthetic aperture radar (SAR) and multi-spectral sensors has shown to be a powerful tool for Earth observation. In this paper, we analyze the potentialities of combining interferometric SAR and multi-spectral data for urban area characterization and monitoring. This study is carried out following a standard multi-source processing chain. First, a pre-processing stage is performed taking into account the underlying physics, geometry, and statistical models for the data from each sensor. Second, two different methodologies, one for supervised and another for unsupervised approaches, are followed to obtain features that optimize the urban rela…
Evolution of the grapevine (Vitis viniferaL.) imprinted by natural and human factorsThis review is one of a selection of papers presented at the symp…
2007
This paper is concerned with vegetative reproduction, which is the only mode of propagation in cultivated grapevines. After a brief summary of the systematics of the Vitaceae the question of the nomenclature of cultivated grapevines is discussed. Intra-varietal variability is discussed using morphological and molecular characteristics. The origins of variation are presented: mutations, foreign nucleic acids, and memory of previous environmental conditions. Grapevines provide characteristic products, leading viticulturalists to make selections among the diversity observed in the vineyard, thus decreasing diversity. Grapevines interact with various environmental agents. One example, the natur…