Search results for "Reproduction"
showing 10 items of 752 documents
Les causes biologiques de la régression du bleuet (Centaurea cyanus L.)
2012
National audience; Dans les agroécosystèmes, un déclin de la diversité biologique causé par l’intensification des pratiques agricoles est actuellement observé. Parmi les espèces adventices, toutes ne répondent pas de la même façon à ces changements. Des traits biologiques spécifiques pourraient expliquer le déclin de certaines et la réussite d’autres. Ainsi, mieux comprendre les causes biologiques de la régression permettrait de mettre en place des stratégies de gestion dans ces systèmes agricoles intensifs. Le bleuet (Centaurea cyanus L.) est une messicole spécialiste de l’agroécosystème qui est actuellement en régression dans l’ouest de l’Europe . Cette espèce est par ailleurs considérée …
L'homosexualité et la constitution de la famille : situations française et européenne
2016
The 2013-404 law of 17 May 2013 which opened up the possibility for people of the same gender to get married shows a turning point for the family rights in France. This law, sometimes described as a real tsunami, is the outcome of taking into account the homosexuals' claim for starting a family. Before 2013 the French right did not allow a homosexual couple to be a homoparental family. It did not authorize people of the same gender to get married. Moreover Assisted Reproduction is only reserved to heterosexual couples and Gestation for Others is strictly forbidden in France. This seemingly constrained consensus on the non-legal recognition of the homosexual family is reinforced by the Europ…
La transmission des inégalités par l'école : une approche politique
2000
International audience
Illustration et intermédialité, entre gravure et photographie
2014
International audience; Cet article envisage le rôle de l’illustrateur comme « changeur » du texte en image dans les manuels sur l’illustration parus dans les années 1890, alors que les procédés photomécaniques marquent des progrès décisifs. La transaction intermédiale particulière qui s’opère dans le livre illustré est envisagée à cette époque du point de vue des supports techniques conçus comme des écrans interposés entre l’original et sa reproduction. Les écrits de Liliane Louvel, Gérard Genette, Hans Belting, Jacques Rancière et Philippe Dubois sont convoqués pour montrer comment l’évolution de l’illustration s’inscrit alors dans le conflit médial opposant gravure et photographie et ref…
Social Inequality in French Education : Extent and Complexity of the Issues
2007
Educational inequality is a matter of acute concern in France as it is in most democratic countries. We rely on schools to assess the skill levels of all students and on this basis to guide them into employment in a way which is impartial and independent of their social origins. However, since the end of the 1960s, French sociology has very cogently denounced sharp and persistent inequalities both in access to different levels of education and in academic success understood more narrowly. This critique took the form of a general theory, presented by Bourdieu and Passeron in 1970 in Reproduction, which made social inequalities a necessary outcome of the way in which school systems worked.
Incubation behaviour of Great Tits Parus major in response to ambient temperature in three contrasting Mediterranean habitats
2021
Esta tesis fue leída el 14 de junio de 2021 en la Universidad de Valencia y forma parte del Doctoral Program in Biodiversity and Evolutionary Biology (RD 99/2011) del Departamento de Zoología de la Facultad de Ciencias Biológicas de dicha universidad.-168 pp.-
Long-lasting effect of stress on susceptibility of a freshwater clam to copepod parasitism.
2005
The question whether a stress event can have a long-lasting effect on susceptibility to parasites was studied using a freshwater bivalve clam and its crustacean parasite as a model system. Anodonta piscinalis clams were collected from 2 populations during August–September 2002. Clams were transported to the laboratory and marked. The stressed clams were subjected to low oxygen for 25 days, while the unstressed control clams were caged in their lakes of origin for the same period. Then the clams were transported to a third lake where they were exposed to natural infections by the ergasilid copepod, Paraergasilus rylovi , 11 months after the stress event. The stressed clams were more intensiv…
The evolutionary dynamics of adaptive virginity, sex-allocation and altruistic helping in haplodiploid animals
2018
In haplodiploids, females can produce sons from unfertilized eggs without mating. However, virgin reproduction is usually considered to be a result of a failure to mate, rather than an adaptation. Here, we build an analytical model for evolution of virgin reproduction, sex-allocation, and altruistic female helping in haplodiploid taxa. We show that when mating is costly (e.g., when mating increases predation risk), virginity can evolve as an adaptive female reproductive strategy. Furthermore, adaptive virginity results in strongly divergent sex-ratios in mated and virgin queen nests ("split sex ratios"), which promotes the evolution of altruistic helping by daughters in mated queen nests. H…
ART AND TECHNIQUE: ARTISTIC REPRODUCTION OF THE ANCIENT BRONZE IL GUERRIERO DA PETRALIA SOTTANA
2016
The reproduction of artistic objects is useful for museological, teaching, and commercial purposes. In some cases, the reproduction is carried out to replace the originals located in outdoor environments and to prevent the deterioration due to weathering or pollution. This article describes the different phases that led to the reproduction of the Il Guerriero da Petralia Sottana. The observation of stylistic characteristics and the physical-chemical investigation were carried out in order to obtain information about the composition of the alloy and the technological properties of the artifact by using Optical Microscopy and X- ray Fluorescence. The reproduction in wax was performed by using…
Evolution of vertebrate survival circuits
2018
Evolution selects those adaptive features that increase reproductive probabilities and facilitate survival. Analysing the brain circuits mediating risk-avoidance (e.g. defense) and those allowing reward-seeking (motivated) behaviours in different vertebrates leads to several main conclusions. First, circuits mediating risk-avoidance are similar in all studied vertebrates, where they include amygdala homologues located in the posterior half of the cerebral hemispheres, in close relationship with the chemosensory systems. Second, in all vertebrates, reward-seeking behaviours involve the activity of tegmento-striatal dopaminergic pathways, plus other inputs to the ventral striatum, including a…