Two sites of the Neandertal-associated Middle Paleolithic of Iberia, dated to as early as approximately 50,000 years ago, yielded perforated and pigment-stained marine shells. At Cueva de los Aviones, three umbo-perforated valves of Acanthocardia and Glycymeris were found alongside lumps of yellow and red colorants, and residues preserved inside a Spondylus shell consist of a red lepidocrocite base mixed with ground, dark red-to-black fragments of hematite and pyrite. A perforated Pecten shell, painted on its external, white side with an orange mix of goethite and hematite, was abandoned after breakage at Cueva Antón, 60 km inland. Comparable early modern human-associated material from Africa and the Near East is widely accepted as evidence for body ornamentation, implying behavioral modernity. The Iberian finds show that European Neandertals were no different from coeval Africans in this regard, countering genetic/cognitive explanations for the emergence of symbolism and strengthening demographic/social ones.

We report on the growth of AlxGa1-xN nanowires by plasma-assisted molecular beam epitaxy for x in the 0.3-0.8 range. Based on a combination of macro- and micro-photoluminescence, Raman spectroscopy, x-ray diffraction and scanning electron microscopy experiments, it is shown that the structural and optical properties of AlGaN NWs are governed by the presence of compositional fluctuations associated with strongly localized electronic states. A growth model is proposed, which suggests that, depending on growth temperature and metal adatom density, macroscopic composition fluctuations are mostly of kinetic origin and are directly related to the nucleation of the AlGaN nanowire section on top of the GaN nanowire base which is used as a substrate.

Pillared derivatives of γ-zirconium phosphate, having the general formula ZrPO4[O2P(OH)2]1 - x [O2POH−(CH2) n −HOPO2] x /2·mH2O (n = 4, 6, 8, 10, 12, and 16), were prepared by soft topotactic reactions between colloidal dispersions of exfoliated lamellae of γ−ZrPO4[O2P(OH)2]·2H2O and 1,n-alkanediphosphonic acid solutions. In these compounds the interlayer distance can be easily modulated almost continuously by increasing the number of the carbon atoms in the alkyl chain, while the lateral distance of the pillars can be varied over a large interval according to the degree of pillaring. The interlayer distance of compounds with a low percentage of pillaring decreased appreciably when the intercalated solvent was eliminated (e.g., by dehydration). The reversible elongation and shortening property of the interlayer suggests that the alkyl chains, being nonrigid pillars, tend to fill up empty spaces created by the loss of interpillar solvent by adopting different conformations in the interlayer region. The large interpillar spaces filled by solvent can be seen as “tailor-made molecular vessels,” in which specific reactions could be carried out in a restricted environment.

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M = 1208.0, yellow. triclinic PI. 7 = 95.47(2) . I,'= 2361.5 A3. 2 =2. pL,s,cd = 1.699. p (Cu,,) = 33.755 cm-'. 4921 reflections (3 < 0 < 51 . k h + k + I ) Mere collected at -100 C on a crystal of 0.26 x 0.20 x 0.09 mm. empirical absorption correction were applied.