Social play in African savannah elephants may inform selection against aggression.

In social groups, competition for individual advantage is balanced with cooperation, for the collective benefit. Selection against aggression has favored cooperation and non-aggressive competitive strategies. Because social play is a behavioral system that fluctuates between cooperation and competition, selection against aggression might have especially influenced this behavior.

Fractional Sobolev spaces on Riemannian manifolds.

This article studies the canonical Hilbert energy on a Riemannian manifold for , with particular focus on the case of closed manifolds. Several equivalent definitions for this energy and the fractional Laplacian on a manifold are given, and they are shown to be identical up to explicit multiplicative constants. Moreover, the precise behavior of the kernel associated with the singular integral definition of the fractional Laplacian is obtained through an in-depth study of the heat kernel on a Riemannian manifold.

Beware! Different methods lead to divergent results on yawn contagion modulation in bonobos.

Contagious yawning (CY)-linked to physiological synchronization and possibly emotional contagion-occurs when one individual's yawn induces yawning in others. CY was investigated over different time windows (minutes from the triggering stimulus) via naturalistic or experimental studies (using real and video yawns, respectively) with contrasting results, especially in bonobos. We verified whether in bonobos result divergences may derive from different methods.

Lexical skills and gesture use: A comparison between expressive and receptive/expressive late talkers.

Background: Studies on late talkers (LTs) highlighted their heterogeneity and the relevance of describing different communicative profiles.

Aims: To examine lexical skills and gesture use in expressive (E-LTs) vs. receptive-expressive (R/E-LTs) LTs through a structured task.