The ecology of freshwater planarians.

Planarians are on the rise as a model system for regeneration and stem cell dynamics. Almost in parallel the interest in planarian field biology has declined. Besides representing an independent research discipline in its own right, understanding of the natural habitat is also directly relevant to optimizing culture conditions in the laboratory. Moreover, the current laboratory models are but few of hundreds of planarian species worldwide. Their adaptation to a wide range of ecological niches has resulted in a fascinating diversity of regenerative abilities, body size, reproduction strategies, and life expectancy, to name just a few. With the currently ongoing establishment of large planarian species collections, such phenotypic diversity becomes accessible to comparative mechanistic analysis in the laboratory. Overall, we hope that this chapter inspires an integral view of the planarian model system that not only includes the molecular and cellular processes under investigation but also the evolutionary forces that shaped them in the first place

On the Role of Affective Properties in Hedonic and Discriminant Haptic Systems

Common haptic devices are designed to effectively provide kinaesthetic and/or cutaneous discriminative inputs to the users by modulating some physical parameters. However, in addition to this behavior, haptic stimuli were proven to convey also affective inputs to the brain. Nevertheless, such affective properties of touch are often disregarded in the design (and consequent validation) of haptic displays. In this paper we present some preliminary experimental evidences about how emotional feelings, intrinsically present while interacting with tactile displays, can be assessed. We propose a methodology based on a bidimensional model of elicited emotions evaluated by means of simple psychometric tests and statistical inference. Specifically, affective dimensions are expressed in terms of arousal and valence, which are quantified through two simple one-question psychometric tests, whereas statistical inference is based on rank-based non-parametric tests. In this work we consider two types of haptic systems: (i) a softness display, FYD-2, which was designed to convey purely discriminative softness haptic stimuli and (ii) a system designed to convey affective caress-like stimuli (by regulating the velocity and the strength of the “caress”) on the user forearm. Gender differences were also considered. In both devices, the affective component clearly depends on the stimuli and it is gender-related. Finally, we discuss how such outcomes might be profitably used to guide the design and the usage of haptic devices, in order to take into account also the emotional component, thus improving system performance