Trajectory and kinematics of drawing movements are mutually constrained by functional relationships that reduce the degrees of freedom of the hand-arm system. Previous investigations of these relationships are extended here by considering their development in children between 5 and 12 years of age. Performances in a simple motor task--the continuous tracing of elliptic trajectories--demonstrate that both the phenomenon of isochrony (increase of the average movement velocity with the linear extent of the trajectory) and the so-called two-thirds power law (relation between tangential velocity and curvature) are qualitatively present already at the age of 5. The quantitative aspects of these regularities evolve with age, however, and steady-state adult performance is not attained even by the oldest children. The power-law formalism developed in previous reports is generalized to encompass these developmental aspects of the control of movement.

We propose a novel quasiparticle interpretation of the equation of state of deconfined QCD at finite temperature. Using appropriate thermal masses, we introduce a phenomenological parametrization of the onset of confinement in the vicinity of the predicted phase transition. Lattice results of the energy density, the pressure and the interaction measure of pure SU (3) gauge theory are excellently reproduced. We find a relationship between the thermal energy density of the Yang-Mills vacuum and the chromomagnetic condensate B 2 T . Finally, an extension to QCD with dynamical quarks is discussed. Good agreement with lattice data for 2, 2+1 and 3 flavour QCD is obtained. We also present the QCD equation of state for realistic quark masses.

The intramolecular non–Born–Oppenheimer quantum dynamics on conically intersecting potential-energy surfaces is analyzed on the basis of exact (numerical) time-dependent quantum calculations for two representative two-state three-mode vibronic-coupling models. A compact description of the time-dependent dynamics in terms of reduced density matrices of the electronic and vibrational subsystems is introduced. Results are presented for the time evolution of electronic and vibrational coherences, populations, as well as subsystem entropies. It is found that such simple two-state three-mode vibronic coupling models exhibit a rich variety of dissipative phenomena on femtosecond time scales. The numerical results reveal an interesting interplay of driven electronic surface-hopping processes and dephasing of coherent vibrational motion which is presumably a generic feature of ultrafast internal conversion processes in polyatomic molecules.

Radiation damage of self-assembled monolayers, which are prototypes of thin organic layers and highly organized biological systems, shows a strong dependence on temperature. Two limiting cases could be identified. Reactions involving transport of single atoms and small fragments proceed nearly independent of temperature. Reactions requiring transport of heavy fragments are, however, efficiently quenched by cooling. We foresee the combined use of temperature and irradiation by electrons or photons for advanced tailoring of self-assembled monolayers on surfaces. In addition, our results have direct implications for cryogenic approaches in advanced electron and x-ray microscopy and spectroscopy of biological macromolecules and cells.

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