Regioselective access to heterohelicenes through the 1,3-dipolar cycloaddition of sydnones with arynes is described. Novel and poly(hetero)aromatic aryne precursors allowed introduction chemical diversity over multiple positions helical scaffolds. The origins unconventional regioselectivity during steps was systematically investigated using density functional theory (DFT) calculations, unveilin...

The problem of unbounded uniaxial chiral omega media in the presence of both static electric and magnetic point charges is investigated. For this purpose scalar electric and magnetic potentials in these media are introduced. Using these potentials, the corresponding electric and magnetic fields are determined. The similar problem of static electric and magnetic current sources with the goal of ...

Mouvance « Bio-sémiotique » http://www.ento.vt.edu/~sharov/biosem/ Biosemiotics (bios=life & semion=sign) is an interdisciplinary science that studies communication and signification in living systems. Communication is the essential characteristic of life. An organism is a message to future generations that specifies how to survive and reproduce. Any autocatalytic system transfers information (...

Interaction between electric charges is an important factor in protein adsorption. Similar charge signs on the protein and the sorbent surface opposes adsorption, but whether it prevents ad.: sorption depends on other factors such as dehydration of the protein and the sorbent and structural rearrangements in the protein molecule. Ribonuclease, that does not strongly change its structure upon ad...

The notion of subject in human language has a privileged status relative to other arguments. This special status is manifested in the behavior of subjects at the morphological, syntactic, semantic and discourse levels. Here we bring evidence that subjects have privileged status at the lexical level as well, by analyzing lexicalization patterns of verbs in three different sign languages. Our ana...

Article history: Received 1 August 2007 Received in revised form 22 May 2009 Accepted 26 May 2009

Complexity has been linked to ease of learning. This article explores the roles of two measures of complexity – feature economy and logical complexity – in the acquisition of sets of signs, taken from a small sign language that serves as an analogue of plosive inventories in spoken language. In a learning experiment, participants acquired data sets that varied in feature economy and logical com...