Roland M. Friedrich

Effect of actinomycin D on nucleic acid hybridization The cause of erroneous DNA elongation during DNA synthesis of RNA tumor viruses in vitro

Actinomycin D, known for its suppression of cellular RNA synthesis and for the reduction of the rate of synthesis of double-stranded DNA by the RNA tumor virus RNA-dependent DNA polymerase, was found to interact with single-stranded DNA in such a way as to inhibit DNA . DNA and DNA . RNA hybridizations. This finding is discussed in the light of the observation that DNA elongation during DNA synthesis of RNA tumor viruses is blocked in vitro in the presence of actinomycin D. It thus supports the model that hybridization is a necessary step during RNA tumor virus DNA synthesis.

Mathematical Logic in the Human Brain: Semantics

As a higher cognitive function in humans, mathematics is supported by parietal and prefrontal brain regions. Here, we give an integrative account of the role of the different brain systems in processing the semantics of mathematical logic from the perspective of macroscopic polysynaptic networks. By comparing algebraic and arithmetic expressions of identical underlying structure, we show how the different subparts of a fronto-parietal network are modulated by the semantic domain, over which the mathematical formulae are interpreted. Within this network, the prefrontal cortex represents a system that hosts three major components, namely, control, arithmetic-logic, and short-term memory. This prefrontal system operates on data fed to it by two other systems: a premotor-parietal top-down system that updates and transforms (external) data into an internal format, and a hippocampal bottom-up system that either detects novel information or serves as an access device to memory for previously acquired knowledge.

The correlator toolbox, metrics and moduli

Abstract We discuss the possible set of operators from various boundary conformal field theories to build meaningful correlators that lead via a Lowner type procedure to generalisations of SLE ( κ , ρ ) . We also highlight the necessity of moduli for a consistent kinematic description of these more general stochastic processes. As an illustration we give a geometric derivation of SLE ( κ , ρ ) in terms of conformally invariant random growing compact subsets of polygons. Further, we also mention a related class of polyhedral SLE ( κ , ρ , ρ ) processes. In the case of polygons, the parameters ρ j are related to the exterior angles. We also show that SLE ( κ , ρ ) can be generated by a Brownian motion in a gravitational background, where the metric and the Brownian motion are coupled. The metric is obtained as the pull-back of the Euclidean metric of a fluctuating polygon.

Correction: Mathematical Logic in the Human Brain: Semantics

There were multiple errors in the affiliations. The correct affiliations are: Roland M. Friedrich Institute for Mathematics, Humboldt University Berlin, Berlin, Germany and Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany Angela D. Friederici Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany