Search results for "InSe"

EVIDENCE FOR KIN-STRUCTURED GROUP FOUNDING AND LIMITED JUVENILE DISPERSAL IN THE SUB-SOCIAL SPIDER STEGODYPHUS LINEATUS (ARANEAE, ERESIDAE)

2001

Abstract In sub-social spiders, restricted dispersal of young (i.e., natal philopatry) and the potential for inbreeding could contribute to within-population subdivision, thus resulting in a population structure similar to that found in social congeners. In this context, we analyzed the origin and mode of individual distribution patterns and their contribution to within-population structure in juveniles of the sub-social spider Stegodyphus lineatus. We investigated the distribution of juveniles for four months after leaving the maternal nest using allozyme genetic markers. We found that isolated groups of juveniles consisted predominantly of siblings, whereas larger aggregations of individu…

A TEST FOR REPRODUCTIVE SEPARATION OF ALTERNATE GENERATIONS IN A BIENNIAL SPIDER, ARANEUS DIADEMATUS (ARANEAE, ARANEIDAE)

2002

In Denmark, two seemingly distinct size-classes, 3rd and 4th instar juveniles and repro- ductive adults, of Araneus diadematus are found during every breeding season in autumn, indicating a non-overlapping biennial life-cycle. We tested the hypothesis that alternate generations might experience a degree of reproductive isolation, using the distribution of nuclear (allozyme) and maternal (mtDNA) genetic markers. Individuals of a locality behaved as belonging to a random mating population, irrespective of size. No differences were found between any size-class pairs, within and between 2 yr, or among geographically distant samples. Processes that may lead to this result are discussed: the bien…

Observations on a new species of Unicapsula (Myxosporida) in the fish Maena smaris (L.) by conventional and electronmicroscopy

1975

A myxosporidian parasite believed to be congeneric with Unicapsula muscularis Davis (1924), type (and only) species of this genus, was found in the dorsal muscles of the fish Maena smaris (L.) at Banyuls-sur-Mer, France. The spores were tripartite, with corresponding components of the three parts differentially developed. One part consisted of a small shell valve overlying no more than a trace of sporoplasm but covering a polar apparatus with well-developed polar capsule. Each of the other two parts consisted of a long shell valve covering a large sporoplasm and a polar apparatus with only the rudiment of a polar capsule. Electron microscope pictures of the trophozoite showed evidence of pi…

Les stages en cours d'études ont-il une valeur professionnelle ?

2010

Nous proposons dans ce travail d'étudier la valeur professionnelle des stages qui sont proposés aux étudiants. Nous utilisons des informations disponibles dans l'enquête Génération " 2004 " du Céreq sur le stage le plus long effectué par le jeune. D'abord, une typologie statistique en 5 grandes catégories de stages a été construite. Elle oppose notamment des stages " formateurs et gratifiés ", souvent réservés aux plus diplômés et des stages " courts sans aucune gratification". Nous avons ensuite étudié les liens entre le type de stage effectué par les étudiants et leur insertion professionnelle. Nos résultats montrent " toutes choses égales par ailleurs " que plus le stage est gratifié et …

Insertion des jeunes : 1986, l'année stage

1986

Évaluer les effets des stages pour publics "en difficulté", des problèmes qui ne sont pas seulement d'ordre méthodologique ... réflexions à partir d'…

1996

How to assess the impact of courses aimed at problem-people : a discussion of a case-study In the context of high unemployment, a considerable course market has developped but their impact on finding a job remains quite uncertain. This paper provides an evaluation of a course aimed at problem job seekers, carried out in Bourgogne (middle-east region). Course attendance is most likely to be linked to job hunting and the setting up of more elaborate career plans. It looks as if other psychological changes are negligeable. Moreover, this assessment raises the question of the possible evil effects of such development on a more general level.

Tribolium castaneum immune defense genes are differentially expressed in response to Bacillus thuringiensis toxins sharing common receptor molecules …

2015

In Tribolium castaneum larvae we have demonstrated by RNA interference knockdown that the Bacillus thuringiensis Cry3Ba toxin receptors Cadherin-like and Sodium solute symporter proteins are also functional receptors of the less active Cry3Aa toxin. Differences in susceptibility to B. thuringiensis infection might not only rely on toxin-receptor interaction but also on host defense mechanisms. We compared the expression of the immune related genes encoding Apolipophorin-III and two antimicrobial peptides, Defensin3 and Defensin2 after B. thuringiensis challenge. All three genes were up-regulated following Cry3Ba spore-crystal intoxication whereas only Defensins gene expression was induced u…

Starvation endurance in the antTemnothorax nylanderidepends on group size, body size and access to larvae

2013

Social interactions in animal groups can buffer environmental stress and may enhance survival under unfavourable conditions. In the present study, the impact on starvation endurance of social group, access to larvae and cold shock is studied in the ant Temnothorax nylanderi Forster. Resource sharing is expected to lead to grouped workers surviving longer than isolated ones. Access to larvae may increase longevity if larvae serve as food, or may interfere with survival if they induce caring behaviour in workers. Cold shock serves as a stress factor and a negative influence on survival is expected. The results show that isolated workers have a shorter lifespan than grouped workers, which in t…

Structure Learning in Nested Effects Models

2007

Nested Effects Models (NEMs) are a class of graphical models introduced to analyze the results of gene perturbation screens. NEMs explore noisy subset relations between the high-dimensional outputs of phenotyping studies, e.g., the effects showing in gene expression profiles or as morphological features of the perturbed cell. In this paper we expand the statistical basis of NEMs in four directions. First, we derive a new formula for the likelihood function of a NEM, which generalizes previous results for binary data. Second, we prove model identifiability under mild assumptions. Third, we show that the new formulation of the likelihood allows efficiency in traversing model space. Fourth, we…

Insertion Reactions of Neutral Phosphidozirconocene Complexes as a Convenient Entry into Frustrated Lewis Pair Territory

2016

International audience; Neutral phosphidozirconocene complexes [Cp2Zr(PR2)Me] (Cp=cyclopentadienyl; 1a: R=cyclohexyl (Cy); 1b: R=mesityl (Mes); 1c: R=tBu) undergo insertion into the Zr-P bond by non-enolisable carbonyl building blocks (O=CRR), such as benzophenone, aldehydes, paraformaldehyde or CO2, to give [Cp2Zr(OCRRPR2)Me] (3-7). Depending on the steric bulk around P, complexes 3-7 react with B(C6F5)(3) to give O-bridged cationic zirconocene dimers that display typical frustrated Lewis pair (FLP)/ambiphilic ligand behaviour. Thus, the reaction of {[Cp2Zr(-OCHPhPCy2)][MeB(C6F5)(3)]}(2) (10a) with chalcone results in 1,4 addition of the Zr+/P FLP, whereas the reaction of {[Cp2Zr(-OCHFcPCy…