Search results for "age effect"
showing 10 items of 34 documents
A methodological approach to analyze the territorial appropriation of high-speed rail from interactions between actions and representations of local …
2019
International audience; Because it is difficult to separate the specific transport impact from other factors influencing economic and spatial development, the focus in research is increasingly on understanding the process by which territorial changes occur in order to explain how economic and social agents and local authorities have appropriated new transportation systems. This appropriation plays a crucial part in territorial dynamics. The diversity of economic and spatial changes produced by high-speed rail indicates the existence of multiple modes of appropriation which vary according to the location of stations, the mobilization of local stakeholders confronted with the transport operat…
Molecular-dynamics simulation of a glassy polymer melt: Rouse model and cage effect
1999
We report results of molecular-dynamics simulations for a glassy polymer melt consisting of short, linear bead-spring chains. It was shown in previous work that this onset of the glassy slowing down is compatible with the predictions of the mode coupling theory. The physical process of `caging' of a monomer by its spatial neighbors leads to a distinct two step behavior in the particle mean square displacements. In this work we analyze the effects of this caging process on the Rouse description of the melt's dynamics. We show that the Rouse theory is applicable for length and time scales above the typical scales for the caging process. Futhermore, the monomer displacement is compared with si…
Initial reaction steps in the condensed-phase decomposition of propellants
2002
Understanding the reaction mechanisms for the decomposition of NO2-containing energetic materialsin the condensed phase is critical to our development of detailed kinetic models of these energetic materials in propellant combustion. To date, the reaction mechanisms in the condensed phase have been represented by global reactions. The detailed elementary reactions subsequent to the initial NO2 bond scissioning are not known. Using quantum chemical calculations, we have investigated the possible early steps in the decomposition of energetic materials that can occur in the condensed phase. We have used methylnitrate, methylnitramine, and nitroethane as prototypes for O−NO2, N−NO2 and C−NO2 nit…
Long-Term Coexistence of Rotifer Cryptic Species
2011
Despite their high morphological similarity, cryptic species often coexist in aquatic habitats presenting a challenge in the framework of niche differentiation theory and coexistence mechanisms. Here we use a rotifer species complex inhabiting highly unpredictable and fluctuating salt lakes to gain insights into the mechanisms involved in stable coexistence in cryptic species. We combined molecular barcoding surveys of planktonic populations and paleogenetic analysis of diapausing eggs to reconstruct the current and historical coexistence dynamics of two highly morphologically similar rotifer species, B. plicatilis and B. manjavacas. In addition, we carried out laboratory experiments using …
Optical properties of chlorine-and oxygen-related defects in SiO$_2$ glass and optical fibers
2018
International audience; Photoinduced processes involving chlorine molecules in synthetic silica were studied. Interstitial Cl$_2$ in SiO$_2$ are prevented from VIS/UV photolysis by cage effect. However, they react with oxygen interstitials yielding photosensitive ClClO molecules absorbing at 264nm.
Food selectivity and pickiness in adulthood: an age and gender-related behaviour?
2013
Food pickiness –or selectivity- is a behavior which may lead to a lack of variety and an unbalanced diet. While this trait has been studied in children, pickiness in adults has been more rarely explored and only recently in French elderly1. The first aim of the present work was to identify if pickiness varies according to age and gender in adults. The second aim was to examine the link between the selectivity score and self-reported degree of pickiness. Four hundred French adults from 25 to 75 years old answered an online survey. Respondents were asked to tick each food they dislike among a list of 71 food items. The selectivity score was the number of disliked food items1. Moreover, partic…
Differential activation of neural networks in an odor recognition task: an event-related fMRI study
2010
Differential activation of neural networks in an odor recognition task: an event-related fMRI study. 32. Annual meeting (AChemS)
Interspecific extrinsic and intrinsic competitive interactions in egg parasitoids
2012
Interspecific competitive interactions can occur either between adult parasitoids searching/exploiting hosts (extrinsic competition) or between parasitoid larvae developing within the same host (intrinsic competition). Understanding how interspecific competition between parasitoids can affect pest suppression is important for improving biological pest control. The purpose of this work was to review both extrinsic and intrinsic competition between egg parasitoid species. These are organisms that are often candidates for biological control programs due to their ability to kill the pest before the crop feeding stage. We first reviewed the literature about interspecific competitive abilities of…
Shakedown of Structures Accounting for Damage Effects
2002
Shakedown theory for elastic-plastic-damage materials is exposed. Two kinds of shakedown are considered: i) Enlarged shakedown (or simply shakedown), in which both plastic deformations and damage eventually cease, after which the structural response is purely elastic; ii) Weak-form shakedown, in which plastic deformations eventually cease together with their consequences (including ductile damage), not necessarily damage from other sources (which are however escluded by assumption). An (enlarged) shakedown static-type theorem is given for a class of D-stable structures. Sufficient theorems of weak-form shakedown are provided, i.e. a static-type one (quite similar to that of Hachemi and Weic…
Influence of age on French consumers’ environmentally sustainable behaviour
2011
Présentation confidentielle; absent