458 research outputs found

    Caractérisation, variabilité et héritabilité des traits de personnalité chez les téléostéens

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    This thesis is organized in three principal parts. The first part of this thesis highlights the existence of coping style in seabass, revealing links between behavioral and physiological responses following a stress. The proactive individuals showed a weaker activation of the HPI axis, resulting in a lesser increase of plasmatic cortisol levels after a stress compared to reactive fish. However, the links between personality traits and activation of the dopaminergic and serotonergic systems could not be clearly demonstrated. The individual tests appeared discriminating personality, but did not allow observing coherent responses in time likely because of the stressing character of the isolated situation in this social species. The use of tests in group appeared better adapted and made it possible to characterize a significant number of individual, a necessary step when one aims at characterizing the genetic variability of the behavioural traits. Finally, variability observed underlined important adaptation capacities of this species. The second part demonstrated the existence of links between personality traits and feeding strategies. The analysis of the social structure highlighted a cooperative strategy concerning the acquisition of food with a specialization of certain individuals in the group. Lastly, the third part showed genetic correlations between coping styles, personality traits and phenotypes, letting foresee a possible selection of the personality traits in a production context. The level of domestication proved to have an influence on the links between personality and growth potential. The use of all these coping style and personality traits could be an additional tool to improve the process of domestication, allowing for example the selection of divergent coping styles which could correspond to individuals more resistant to diseases, or better adapted to their environment.Cette thèse est organisée en trois parties principales. La première partie de cette thèse a permis de mettre en évidence l’existence de coping style chez le bar, révélant des liens entre réponses comportementales et physiologiques suite à un stress. Les individus proactifs montraient une plus faible activation de l’axe HPI, résultant en une moindre augmentation des taux de cortisol plasmatique après un stress que les individus réactifs. Cependant, les liens entre traits de personnalité et activation des systèmes dopaminergiques et sérotoninergiques n’ont pas pu être clairement mis en évidence. Les tests individuels se sont révélés discriminants de la personnalité, mais n’ont pas permis d’observer des réponses cohérentes dans le temps en raison du caractère stressant de l’isolement chez cette espèce sociale. L’utilisation de tests en groupe est apparue mieux adaptée et a permis de caractériser un nombre important d’individus, étape nécessaire à toutes études visant à caractériser la variabilité génétique des traits comportementaux. La variabilité observée met en avant d’importantes capacités d’adaptation chez cette espèce. La seconde partie a mis en avant l’existence de liens entre traits de personnalité et stratégies d’approvisionnement en nourriture. L’analyse de la structure sociale chez cette espèce a mis en évidence une stratégie coopérative concernant l’acquisition de la nourriture avec une spécialisation de certains individus dans le groupe. Enfin, la troisième partie a permis l’observation de liens génétiques entre traits de personnalité et caractères phénotypiques, laissant entrevoir une possible sélection des caractères de personnalité dans un contexte de production piscicole. Le niveau de domestication s’est révélé avoir une influence sur les liens entre personnalité et potentiel de croissance. L’utilisation de ces coping styles et traits de personnalité pourrait être un outil supplémentaire pour améliorer le processus de domestication, permettant par exemple la sélection de coping styles divergents qui pourraient correspondre à des individus plus résistants aux maladies, ou mieux adaptés à leur environnement

    Profit Shifting Frictions and the Geography of Multinational Activity

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    We develop a quantitative general equilibrium model of multinational activity embedding corporate taxation and profit shifting. In addition to trade and investment frictions, our model shows that profit-shifting frictions shape the geography of multinational production. Key to our model is the distinction between the corporate tax elasticity of real activity and profit shifting. The quantification of our model requires estimates of shifted profits flows. We provide a new, model-consistent methodology to calibrate bilateral profit-shifting frictions based on accounting identities. We simulate various tax reforms aimed at curbing tax-dodging practices of multinationals and their impact on a range of outcomes, including tax revenues and production. Our results show that the effects of the international relocation of firms across countries are of comparable magnitude as the direct gains in taxable income

    EmoNets: Multimodal deep learning approaches for emotion recognition in video

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    The task of the emotion recognition in the wild (EmotiW) Challenge is to assign one of seven emotions to short video clips extracted from Hollywood style movies. The videos depict acted-out emotions under realistic conditions with a large degree of variation in attributes such as pose and illumination, making it worthwhile to explore approaches which consider combinations of features from multiple modalities for label assignment. In this paper we present our approach to learning several specialist models using deep learning techniques, each focusing on one modality. Among these are a convolutional neural network, focusing on capturing visual information in detected faces, a deep belief net focusing on the representation of the audio stream, a K-Means based "bag-of-mouths" model, which extracts visual features around the mouth region and a relational autoencoder, which addresses spatio-temporal aspects of videos. We explore multiple methods for the combination of cues from these modalities into one common classifier. This achieves a considerably greater accuracy than predictions from our strongest single-modality classifier. Our method was the winning submission in the 2013 EmotiW challenge and achieved a test set accuracy of 47.67% on the 2014 dataset

    Mercury and methylmercury concentrations in high altitude lakes and fish (Arctic charr) from the French Alps related to watershed characteristics

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    International audienceTotal mercury (THg) andmethylmercury (MeHg) concentrations were measured in the muscle of Arctic charr (Salvelinus alpinus) and in the water column of 4 lakes that are located in the French Alps. Watershed characteristics were determined (6 coverage classes) for each lake in order to evaluate the influence of watershed composition on mercury and methylmercury concentrations in fish muscle and in the water column. THg and MeHg concentrations in surface water were relatively low and similar among lakes and watershed characteristics play a major role in determining water column Hg and MeHg levels. THg muscle concentrations for fish with either a standardized length of 220 mm, a standardized age of 5 years or for individualuals did not exceed the 0.5 mg kg−1 fish consumption advisory limit established for Hg by the World Health Organization (WHO, 1990). These relatively low THg concentrations can be explained by watershed characteristics, which lead to short Hg residence time in the water column, and also by the short trophic chain that is characteristic of mountain lakes. Growth rate did not seem to influence THg concentrations in fish muscles of these lakes and we observed no relationship between fish Hg concentrations and altitude. This study shows that in the French Alps, high altitude lakes have relatively low THg and MeHg concentrations in both the water column and in Arctic charr populations. Therefore, Hg does not appear to present a danger for local populations and the fishermen of these lakes

    Study of dispersion by NMR: comparison between NMR measurements and stochastic simulation

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    Dispersion remains, today, a highly topical subject. Our group has been interested in characterizing this phenomenon by pulsed-field-gradient NMR technique. Direct measurement of the dispersion coefficient can be done with a Pulsed Gradient Spin Echo (PGSE) sequence by assuming that the asymptotic regime is reached. In unsteady state, the propagator formalism is used. To better understand these measurements, the NMR experiment is modeled using a stochastic simulation (random walks) and compared with experimental results. The comparison is made for the simple case of Poiseuille flow in a circular tube (Taylor-Aris dispersion)

    Study of dispersion by NMR: comparison between NMR measurements and stochastic simulation

    Get PDF
    Dispersion remains, today, a highly topical subject. Our group has been interested in characterizing this phenomenon by pulsed-field-gradient NMR technique. Direct measurement of the dispersion coefficient can be done with a Pulsed Gradient Spin Echo (PGSE) sequence by assuming that the asymptotic regime is reached. In unsteady state, the propagator formalism is used. To better understand these measurements, the NMR experiment is modeled using a stochastic simulation (random walks) and compared with experimental results. The comparison is made for the simple case of Poiseuille flow in a circular tube (Taylor-Aris dispersion)

    Methodology for cost-effective energy and carbon emissions optimization in building renovation (Annex 56)

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    "Energy in Buildings and Communities Programme, March 2017"Buildings are responsible for a major share of energy use and have been a special target in the global actions for climate change mitigation, with measures that aim at improving their energy efficiency, reduce carbon emissions and increase renewable energy use. The IEA-EBC Annex 56 project «Cost-Effective Energy and Carbon Emissions Optimization in Building Renovation» intends to develop the basics for future standards, which aim at maximizing effects on reducing carbon emissions and primary energy use while taking into account the cost-effectiveness of related measures. The IEA EBC Annex 56 project pays special attention to cost effective energy related renovation of existing residential buildings and low-tech office buildings (without air conditioning systems).info:eu-repo/semantics/publishedVersio

    Physiological responses during acute stress recovery depend on stress coping style in European sea bass, Dicentrarchus labrax

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    Individual stress coping style (reactive, intermediate and proactive) was determined in 3 groups of 120 pit tagged European seabass using the hypoxia avoidance test. The same three groups (no change in social composition) were then reared according to the standards recommended for this species. Then, 127 days later, individuals initially characterized as reactive, intermediate or proactive were submitted to an acute confinement stress for 30 min. Blood samples were taken to measure plasma cortisol levels 30 min (Stress30) or 150 min (Stress150) after the end of the confinement stress. Individuals were then sacrificed to sample the telencephalon in order to measure the main monoamines and their catabolites (at Stress30 only). Individuals from Stress150 were sampled for whole brain for a transcriptomic analysis. The main results showed that reactive individuals had a lower body mass than intermediate individuals which did not differ from proactive individuals. The physiological cortisol response did not differ between coping style at Stress30 but at Stress150 when intermediate and proactive individuals had recovered pre stress levels, reactive individuals showed a significant higher level illustrating a modulation of stress recovery by coping style. Serotonin turnover ratio was higher in proactive and reactive individuals compared to intermediate individuals and a significant positive correlation was observed with cortisol levels whatever the coping style. Further, the confinement stress led to a general increase in the serotonin turnover comparable between coping styles. Stress150 had a significant effect on target mRNA copy number (Gapdh mRNA copy number decreased while ifrd1 mRNA copy number increased) and such changes tended to depend upon coping style

    Search for polyoma-, herpes-, and bornaviruses in squirrels of the family Sciuridae

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    Background Squirrels (family Sciuridae) are globally distributed members of the order Rodentia with wildlife occurrence in indigenous and non-indigenous regions (as invasive species) and frequent presence in zoological gardens and other holdings. Multiple species introductions, strong inter-species competition as well as the recent discovery of a novel zoonotic bornavirus resulted in increased research interest on squirrel pathogens. Therefore we aimed to test a variety of squirrel species for representatives of three virus families. Methods Several species of the squirrel subfamilies Sciurinae, Callosciurinae and Xerinae were tested for the presence of polyomaviruses (PyVs; family Polyomaviridae) and herpesviruses (HVs; family Herpesviridae), using generic nested polymerase chain reaction (PCR) with specificity for the PyV VP1 gene and the HV DNA polymerase (DPOL) gene, respectively. Selected animals were tested for the presence of bornaviruses (family Bornaviridae), using both a broad-range orthobornavirus- and a variegated squirrel bornavirus 1 (VSBV-1)-specific reverse transcription-quantitative PCR (RT-qPCR). Results In addition to previously detected bornavirus RNA-positive squirrels no more animals tested positive in this study, but four novel PyVs, four novel betaherpesviruses (BHVs) and six novel gammaherpesviruses (GHVs) were identified. For three PyVs, complete genomes could be amplified with long-distance PCR (LD-PCR). Splice sites of the PyV genomes were predicted in silico for large T antigen, small T antigen, and VP2 coding sequences, and experimentally confirmed in Vero and NIH/3T3 cells. Attempts to extend the HV DPOL sequences in upstream direction resulted in contiguous sequences of around 3.3 kilobase pairs for one BHV and two GHVs. Phylogenetic analysis allocated the novel squirrel PyVs to the genera Alpha- and Betapolyomavirus, the BHVs to the genus Muromegalovirus, and the GHVs to the genera Rhadinovirus and Macavirus. Conclusions This is the first report on molecular identification and sequence characterization of PyVs and HVs and the detection of bornavirus coinfections with PyVs or HVs in two squirrel species. Multiple detection of PyVs and HVs in certain squirrel species exclusively indicate their potential host association to a single squirrel species. The novel PyVs and HVs might serve for a better understanding of virus evolution in invading host species in the future
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