The Virtual Teacher (VT) Paradigm: Learning New Patterns of Interpersonal Coordination Using the Human Dynamic Clamp

The Virtual Teacher paradigm, a version of the Human Dynamic Clamp (HDC), is introduced into studies of learning patterns of inter-personal coordination. Combining mathematical modeling and experimentation, we investigate how the HDC may be used as a Virtual Teacher (VT) to help humans co-produce and internalize new inter-personal coordination pattern(s). Human learners produced rhythmic finger movements whilst observing a computer-driven avatar, animated by dynamic equations stemming from the well-established Haken-Kelso-Bunz (1985) and Schöner-Kelso (1988) models of coordination. We demonstrate that the VT is successful in shifting the pattern co-produced by the VT-human system toward any value (Experiment 1) and that the VT can help humans learn unstable relative phasing patterns (Experiment 2). Using transfer entropy, we find that information flow from one partner to the other increases when VT-human coordination loses stability. This suggests that variable joint performance may actually facilitate interaction, and in the long run learning. VT appears to be a promising tool for exploring basic learning processes involved in social interaction, unraveling the dynamics of information flow between interacting partners, and providing possible rehabilitation opportunities

Thermal spreading as an alternative for the wet impregnation method: Advantages and downsides in the preparation of MoO 3/SiO 2-Al 2O 3 metathesis catalysts

peer reviewedSilica-alumina-supported MoO 3 catalysts are classically prepared via impregnation of the support with a molybdenum salt solution, usually ammonium heptamolybdate, and subsequent drying and calcination (three steps). The downsides of such a route for the synthesis of heterogeneous metathesis catalysts are linked to the limited control on the nature of the MoO x stabilized at the surface, to the uneven distribution of the deposit in the pores of the support, and to the build up of inactive species that find their origin in the wet step of the preparation. In opposition, the direct thermal spreading of molybdenum oxide onto the support is a straightforward (one step) method involving no wet stage. It allows the conversion of bulk MoO 3 crystals to amorphous molybdate species dispersed at the surface of the silica-alumina support. This contribution shows that the catalysts obtained via both methods exhibit similar performances in the self-metathesis of propene to butene and ethene. However, based on XRD, XPS, Raman spectroscopy, ICP-AES, N 2 physisorption, TEM, and MAS-NMR spectroscopy, it is shown that the origin of active and inactive species in the two systems is different. Whereas the activity of wet-made catalysts is limited by the formation of bulky MoO 3 crystals and of aluminum molybdate, the performances of dry-made catalysts are limited by the incomplete spreading of MoO 3 nanocrystallites. © 2010 American Chemical Society

Searching for (Dynamic) Principles of Learning

International audienceIn order to provide a comprehensive and predictive framework for learning and memory, a dynamical pattern theory seeks for very general laws and principles that determine stability and change of behavioral patterns. In the nineties, learning was defined as the emergence of a new stable behavioral pattern involving the alteration of the entire layer of underlying dynamics. Twelve years after, we attempt to evaluate what new insights this approach may afford. After a brief outline of a dynamic theory of learning, we propose three generic principles underlying learning, coming from an overview of experimental work on bimanual coordination and pattern perception: a principle of symmetry conservation, a principle of distance, and a principle of time scales. Throughout this first round of research, a deep question lingers as to the possible existence of two routes to learning. Future research has to establish whether they correspond to two levels of behavioral organization, a metric and a topological level, discerned by Bernstein

Methods for Seafood Authenticity Testing in Europe

56 pages, 5 figuresSeafood authenticity is a key parameter for seafood quality, particularly in Europe where regulations provide a strict framework for seafood labeling. A wide variety of methods are commonly used in control laboratories (private or public) to identify seafood species, but emergent approaches for the development of new and fast DNA- and protein-based methods for species differentiation are also considered. To address the challenges in controlling further labeling requirements in the latest European legislation on seafood product traceability and labeling (Regulation (EU) 1379/2013), a review of the development of methods to identify fishing areas and to distinguish between wild and farmed fish, as well as an overview of the advanced methods that could be used for differentiation of fresh and frozen-thawed fish, is given. These methods will become increasingly important in the near future as the risk-based control of food authenticity is prescribed by the new EU control regulation (Regulation (EU) 2017/625)N