Search results for "Sélectivité"
showing 10 items of 10 documents
Les parcours étudiants en fonction des caractéristiques individuelles
2011
Ce texte vise à préciser quel est l'effet des capitaux culturel et économique des familles sur l'orientation des étudiants. Une comparaison entre les catégories sociales des élèves de classes de 6ème des collèges et celles des étudiants de l'enseignement supérieur permet, dans un premier temps, de décrire la sélectivité sociale qui s'exerce depuis l'entrée au collège jusqu'au études supérieures. Dans un second temps, il sera montré que le coût des études représente une variable explicative des choix scolaires et professionnels en ce qu'il limite les choix des plus démunis alors qu'il ne constitue pas une limite pour les pluis aisés. Enfin, en vue de mieux cerner l'impact respectif et de la …
A categorization and executive functions approach of food rejection in young children
2021
Food neophobia and pickiness are two strong psychological obstacles to young children’s consumption of fruits and vegetables, which are necessary components of a diet that facilitates normal and healthy development. It is therefore of critical importance to investigate the cognitive underpinnings of these two kinds of food rejection to promote the adoption of healthy eating behaviors. Food acceptance and rejection appear to be partly conditioned by children’s knowledge of the food domain. Knowledge allows children to recognize a given food, categorize it, and make inference-based decisions on its properties and possible consequences of consumption. Underdeveloped knowledge may cause food st…
Coadsorption of hydrogen and deuterium on zeolites at cryogenic temperatures : influence of the sorbent’s properties on selectivity
2019
The adsorption of hydrogen and deuterium (single gases and mixtures) was studied on a series of zeolites with varied parameters (Si/Al ratio, nature of the charge-compensating cation, pore geometry and diameter of pore aperture). Thermodynamic adsorption selectivities towards deuterium with respect to hydrogen were measured in a large pressure range (0.1 – 1000 hPa) and for several temperatures (45 – 100 K). The adsorption selectivity was assessed using direct coadsorption measurements performed by manometry coupled with mass spectrometry. For all studied zeolites and experimental conditions, the coadsorption process is selective towards deuterium, in agreement with the literature. However,…
Molecular simulation of mixed gas hydrates in astrophysical conditions
2020
In this PhD work, numerical simulation methods have been used in order to model clathrate hydrates at the molecular scale, in thermodynamic conditions typical of astrophysical contexts. The aim was to characterize the trapping abilities of those peculiar structures of water, by means of the tools used in adsorption studies. The results presented in the present thesis are focused on a couple of chemical species which are found to be abundant in our astrophysical vicinity and are quite similar: carbon monoxide, CO, and nitrogen, N2. Thus, the single-component clathrates of CO and N2, and the mixed hydrate CO-N2 have been studied, mainly using grand canonical Monte Carlo simulations. First, th…
The heterogeneity of new entrants and the selectivity of higher education institutions : some results using data from the CHEERS project
2002
02079; International audience; This paper attempts to test whether there stillexist differences in selectivity between highereducation institutions. Data from the CHEERS(Careers after Higher Education: a EuropeanResearch Survey) project enables us to describethe differences in institutional selectivity ineach country across different fields. We askthe question: how selective are institutionstoday, particularly in the case of Europe andJapan?. In order to describe the selectivity ofhigher education institutions for each field ineach country, we use the entry grade given byeach graduate in the CHEERS data. Despite thedifferences in the grading references in thedifferent countries, these data …
Etude des effets collisionnels dans les molécules tétraédriques. Applications au méthane perturbé par l'argon
1996
This thesis is devoted to the study of relaxational and collisional line-broadening processes in the first vibrational polyads of tetrahedral molecules. In a first part, the particular internal dynamics of such molecules is discussed. The second chapter reviews the literature on phenomena induced by intermolecular interactions involving this type of molecules. More theoretical aspects are developed in the second part. The so-called tetrahedral tensorial formalism adapted to the construction of Hamiltonians and transition moments of tetrahedral molecules is described. Main features of the infrared line-shapes theories and of semi-classical line-broadening and line-shifting calculations are a…
Les coléoptères carabiques sont-ils plus sélectifs face à un risque de prédation ou de compétition ?
2017
Le temps nécessaire à l’évaluation et à l’acceptation d’une ressource est directement lié à sa qualité. Ainsi, les individus s’approvisionnant dans un milieu naturel font face à un compromis entre vitesse de prise de décision et qualité de la ressource (speed-accuracy trade-off). Si la qualité de la ressource est un élément important pour favoriser sa valeur adaptative (fitness), le temps nécessaire au processus de décision n’est plus disponible pour d’autres tâches essentielles comme la vigilance. De plus, une prise de décision trop longue expose aussi les individus à un risque plus important de compétition et de perte d’opportunités. On s’attend à ce que des animaux confrontés à un risque…
La sélectivité par l'âge dans les métiers de l'informatique
2010
National audience
Les enfants difficiles à table : conceptualisation et évolution
2022
L'objectif du présent article est de proposer un état des lieux des études récentes permettant d'offrir un cadre conceptuel et opérationnel au concept de comportement difficile à table, tout en mettant en lumière les conséquences psychologiques pour l'enfant, ainsi que les pratiques éducatives parentales associées. L'article ambitionne aussi de déterminer dans quelle mesure un enfant difficile est un mangeur à risque de développer ultérieurement des troubles du comportement alimentaire (anorexie mentale, ARFID), et quelles seraient les pistes à privilégier, en termes de guidance parentale, pour accompagner l'enfant.
Spilling the beans: The development of conceptual knowledge about food and its links with food rejection in young children (3-7-years-old)
2021
Insufficient dietary variety in children leads to significant nutrient deficiencies and health issues, both in childhood and later life (DeCosta et al., 2017). Cognitive mechanisms, such as categorization and conceptual knowledge, play an important role in understanding and appropriately accepting or rejecting foods (Mura Paroche et al., 2017). The food domain lends itself to many concepts and categories, such as taxonomic (i.e., lamb is meat), thematic (i.e., lamb goes on a plate), or script (i.e., lamb is eaten at dinner). Such knowledge aids accurate recognition, understanding, and appropriate interaction when confronted with foods situated in context. If conceptual knowledge is underdev…