School for Advanced Studies in the Social Sciences

About: School for Advanced Studies in the Social Sciences is a facility organization based out in Villejuif, France. It is known for research contribution in the topics: Population & Politics. The organization has 1230 authors who have published 2084 publications receiving 57740 citations. The organization is also known as: Ecole des Hautes Etudes en Sciences Sociales & EHESS.

Liouville type results for periodic and almost periodic linear operators

Abstract: We are concerned with some extensions of the classical Liouville theorem for bounded harmonic functions to solutions of more general equations. We deal with entire solutions of periodic and almost periodic parabolic equations including the elliptic framework as a particular case. We derive a Liouville type result for periodic operators as a consequence of a result for operators periodic in just one variable, which is new even in the elliptic case. More precisely, we show that if $c\leq0$ and $a_{ij}, b_i, c, f$ are periodic in the same space/time direction, with the same period, then any bounded solution $u$ of $$\partial_t u-a_{ij}(x,t)\partial_{ij}u-b_i(x,t)\partial_iu-c(x,t)u=f(x,t),\quad x\in\R^N,\ t\in\R,$$ is periodic in that direction. We then derive the following Liouville type result: if $c\leq0, f\equiv0$ and $a_{ij}, b_i, c$ are periodic in all the space/time variables, with the same periods, then the space of bounded solutions of the above equation has at most dimension one. In the case of the equation $\partial_t u-Lu=f(x,t)$, with $L$ periodic elliptic operator independent of $t$, the hypothesis $c\leq0$ can be weaken by requiring that the periodic principal eigenvalue of $-L$ is nonnegative. Instead, the periodicity assumption cannot be relaxed, because we explicitly exhibit an almost periodic function $b$ such that the space of bounded solutions of $u''+b(x)u'=0$ in $\R$ has dimension 2, and it is generated by the constant solution and a non-almost periodic solution. Next, a sufficient condition for any bounded solution to be almost periodicis derived. We also treat the case of periodic domains under either Dirichlet or Robin boundary conditions.

Socioeconomic status correlates with measures of Language Environment Analysis (LENA) system: a meta-analysis.

Abstract: Using a meta-analytic approach, we evaluate the association between socioeconomic status (SES) and children's experiences measured with the Language Environment Analysis (LENA) system. Our final analysis included 22 independent samples, representing data from 1583 children. A model controlling for LENATM measures, age and publication type revealed an effect size of rz= .186, indicating a small effect of SES on children's language experiences. The type of LENA metric measured emerged as a significant moderator, indicating stronger effects for adult word counts than child vocalization counts. These results provide important evidence for the strength of association between SES and children's everyday language experiences as measured with an unobtrusive recording analyzed automatically in a standardized fashion.

Resilience of perceptual metacognition in a dual-task paradigm.

Abstract: When people do multiple tasks at the same time, it is often found that their performance is worse relative to when they do those same tasks in isolation. However, one aspect that has received little empirical attention is whether the ability to monitor and evaluate one's task performance is also affected by multitasking. How does dual-tasking affect metacognition and its relation to performance? We investigated this question through the use of a visual dual-task paradigm with confidence judgments. Participants categorized both the color and the motion direction of moving dots, and then rated their confidence in both responses. Across four experiments, participants (N = 87) exhibited a clear dual-task cost at the perceptual level, but no cost at the metacognitive level. We discuss this resilience of metacognition to multitasking costs, and examine how our results fit onto current models of perceptual metacognition.