Indentation of an elastic disk on a circular supporting ring.

Thin elastic two-dimensional systems under compressive stresses may relieve part of their stretching energy by developing out-of-plane undulations. We investigate experimentally and theoretically the indentation of an elastic disk supported by a circular ring and show that compressive stresses are relieved via two different routes: either developing buckles which are spread over the system or developing a d-cone where deformation is concentrated in a subregion of the system. We characterize the indentation threshold for wrinkles or d-cone existence as a function of aspect ratio.

Short photoperiod modulates behavior, cognition and hippocampal neurogenesis in male Japanese quail.

The mechanisms underlying the photoperiodic control of reproduction in mammals and birds have been recently clarified. In contrast, the potential impact of photoperiod on more complex, integrative processes, such as cognitive behaviors, remains poorly characterized. Here, we investigated the impact of contrasted long and short photoperiods (LP, 16 h light/day and SP, 8 h light/day, respectively) on learning, spatial orientation abilities, and emotional reactivity in male Japanese quail.

Object and food novelty induce distinct patterns of c-fos immunoreactivity in amygdala and striatum in domestic male chicks (Gallus gallus domesticus).

Avoidance of novelty, termed neophobia, protects animals from potential dangers but can also impair their adaptation to novel environments or food resources. This behaviour is particularly well described in birds but the neurobiological correlates remain unexplored. Here, we measured neuronal activity in the amygdala and the striatum, two brain regions believed to be involved in novelty detection, by labelling the early gene c-fos following chicks exposure to a novel food (NF), a novel object (NO) or a familiar food (FF).