Foraging society organization: A simple model of a complex transition

The evolutionary development of the hominids that culminated in the appearance of Homo sapiens included the subdivision of the species into societies on the basis of culturally, instead of biologically, constructed differentiation. It is argued that this change must have occurred after the mental ability to formulate and culturally express conceptual structures of extended relationships had been been biologically introduced, and that intergroup competition within a species provided the selective impetus for this more complex form of organization. The combination of conceptual structures for organization at a more extensive scale and the effects of intergroup competition would lead to a restructuring of the whole species into society like groups.     

Apparate

Ohne Zusammenfassung     

Multimodal Analysis of Light-Driven Water Oxidation in Nanoporous Block Copolymer Membranes**

Heterogeneous light-driven catalysis is a cornerstone of sustainable energy conversion. Most catalytic studies focus on bulk analyses of the hydrogen and oxygen evolved, which impede the correlation of matrix heterogeneities, molecular features, and bulk reactivity. Here, we report studies of a heterogenized catalyst/photosensitizer system using a polyoxometalate water oxidation catalyst and a model, molecular photosensitizer that were co-immobilized within a nanoporous block copolymer membrane. Via operando scanning electrochemical microscopy (SECM), light-induced oxygen evolution was determined using sodium peroxodisulfate (Na₂S₂O₈) as sacrificial electron acceptor. Ex situ element analyses provided spatially resolved information on the local concentration and distribution of the molecular components. Infrared attenuated total reflection (IR-ATR) studies of the modified membranes showed no degradation of the water oxidation catalyst under the reported light-driven conditions.     

Controlled Diels–Alder “Click” Strategy to Access Mechanically Aligned Main-Chain Liquid Crystal Networks

Aligned liquid crystal polymers are materials of interest for electronic, optic, biological and soft robotic applications. The manufacturing and processing of these materials have been widely explored with mechanical alignment establishing itself as a preferred method due to its ease of use and widespread applicability. However, the fundamental chemistry behind the required two-step polymerization for mechanical alignment has limitations in both fabrication and substrate compatibility. In this work we introduce a new protection-deprotection approach utilizing a two-stage Diels–Alder cyclopentadiene-maleimide step-growth polymerization to enable mild yet efficient, fast, controlled, reproducible and user-friendly polymerizations, broadening the scope of liquid crystal systems. Thorough characterization of the films by DSC, DMA, POM and WAXD show the successful synthesis of a uniaxially aligned liquid crystal network with thermomechanical actuation abilities.