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We explore the use of brain activity in scenarios of Human-Computer Interaction. Specifically, we aim at the detection of EEG correlates of error awareness to dynamically adapt a Human activity recognition system. We design a Human Computer Interaction experiment which consists in: - a memory game controlled by a Human Activity Recognition System - an EEG - Error Potential (ErrP) detection System We use EEG signal processing to recognize error related potentials (ErrP) on single trial basis. ErrP are emitted when a human observes an unexpected behaviour in a system: we propose and evaluate performance improvements provided by the ErrP detection system as a "teacher" for the on-line adaptation of a user centered activity recognition system. The gesture recognition system becomes self-aware of its performance, and can self-improve through re-occurring detection of ErrP signals.

The H(+)/ATP synthase from yeast mitochondria, MF(0)F(1), was purified and reconstituted into liposomes prepared from phosphatidylcholine and phosphatidic acid. Analysis by mass spectrometry revealed the presence of all subunits of the yeast enzyme with the exception of the K-subunit. The MF(0)F(1) liposomes were energized by acid-base transitions (DeltapH) and a K(+)/valinomycin diffusion potential (Deltaphi). ATP synthesis was completely abolished by the addition of uncouplers as well as by the inhibitor oligomycin. The rate of ATP synthesis was optimized as a function of various parameters and reached a maximum value (turnover number) of 120s(-1) at a transmembrane pH difference of 3.2 units (at pH(in)=4.8 and pH(out)=8.0) and a Deltaphi of 133mV (Nernst potential). Functional studies showed that the monomeric MF(0)F(1) was fully active in ATP synthesis. The turnover increased in a sigmoidal way with increasing internal and decreasing external proton concentration. The dependence of the turnover on the phosphate concentration and the dependence of K(M) on pH(out) indicated that the substrate for ATP synthesis is the monoanionic phosphate species H(2)PO(4)(-).