Sequence learning under uncertainty in children: self-reflection vs. self-assertion

We know that stochastic feedback impairs children's associative stimulus-response (S-R) learning (Crone et al., 2004a; Eppinger et al., 2009), but the impact of stochastic feedback on sequence learning that involves deductive reasoning has not been not tested so far. In the current study, 8- to 11-year-old children (N = 171) learned a sequence of four left and right button presses, LLRR, RRLL, LRLR, RLRL, LRRL, and RLLR, which needed to be deduced from feedback because no directional cues were given. One group of children experienced consistent feedback only (deterministic feedback, 100% correct). In this condition, green feedback on the screen indicated that the children had been right when they were right, and red feedback indicated that the children had been wrong when they were wrong. Another group of children experienced inconsistent feedback (stochastic feedback, 85% correct, 15% false), where in some trials, green feedback on the screen could signal that children were right when in fact they were wrong, and red feedback could indicate that they were wrong when in fact they had been right. Independently of age, children's sequence learning in the stochastic condition was initially much lower than in the deterministic condition, but increased gradually and improved with practice. Responses toward positive vs. negative feedback varied with age. Children were increasingly able to understand that they could have been wrong when feedback indicated they were right (self-reflection), but they remained unable to understand that they could have been right when feedback indicated they were wrong (self-assertion)

Efficient and accurate modeling of electron photoemission in nanostructures with TDDFT

We derive and extend the time-dependent surface-flux method introduced in [L. Tao, A. Scrinzi, New J. Phys. 14, 013021 (2012)] within a time-dependent density-functional theory (TDDFT) formalism and use it to calculate photoelectron spectra and angular distributions of atoms and molecules when excited by laser pulses. We present other, existing computational TDDFT methods that are suitable for the calculation of electron emission in compact spatial regions, and compare their results. We illustrate the performance of the new method by simulating strong-field ionization of C60 fullerene and discuss final state effects in the orbital reconstruction of planar organic molecules

Necessity and Opportunity Entrepreneurs and Their Duration in Self-employment: Evidence from German Micro Data

self-employment, firm survival, necessity entrepreneurs, opportunity entrepreneurs, hazard rates, GSOEP, J23, J24, M13, C41,

Molecular Exchange in a Heteromolecular PTCDA/CuPc Bilayer Film on Ag(111)

The future success of organic semiconductors in electronic or spintronic devices depends crucially on the ability to control the properties of molecular thin films. Metal contacts as well as interfaces formed by different organic materials are of equal importance in this context. A model system contributing to the improvement of the fundamental understanding of such interfaces is the heteromolecular bilayer film formed by 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) grown on a well ordered CuPc monolayer on Ag(111). Using complementary experimental techniques, we are able to reveal a molecular exchange across this heteromolecular interface. At the initial stage of the PTCDA deposition, some of these molecules diffuse into the CuPc layer and displace CuPc molecules to the second layer. This inhibits the formation of a smooth interface between both species and results in a structurally disordered heteromolecular CuPc-PTCDA film in the first and randomly arranged CuPc molecules as well as ordered PTCDA islands in the second layer. While the second organic layer is electronically decoupled from the underlying layer, the first layer, although disordered, shows a charge reorganization and an adsorption height alignment of CuPc and PTCDA as it is known for highly ordered heteromolecular monolayer structures on Ag(111). The molecular exchange, which we consistently find in all our experimental data, is the result of a lower adsorption energy gain of PTCDA on Ag(111) compared to CuPc on Ag(111)