Paleolithic cave art is an exceptional archive of early human symbolic behavior, but because obtaining reliable dates has been difficult, its chronology is still poorly understood after more than a century of study. We present uranium-series disequilibrium dates of calcite deposits overlying or underlying art found in 11 caves, including the United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage sites of Altamira, El Castillo, and Tito Bustillo, Spain. The results demonstrate that the tradition of decorating caves extends back at least to the Early Aurignacian period, with minimum ages of 40.8 thousand years for a red disk, 37.3 thousand years for a hand stencil, and 35.6 thousand years for a claviform-like symbol. These minimum ages reveal either that cave art was a part of the cultural repertoire of the first anatomically modern humans in Europe or that perhaps Neandertals also engaged in painting caves.

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Sb2S3 thin films have been obtained by physical vapour deposition on LiNbO3 and glass substrates. Films with amorphous structure originally became polycrystalline by annealing in a sulfur atmosphere. Changes in optical and structural properties have been studied as a function of annealing temperature. A drastic variation in optical transmission, energy gaps, refractive index, crystallite size, etc is observed at a temperature near 200 °C.

Structural and microstructural properties of synthetic thin films of pyrite (FeS2−x), prepared by thermal sulfuration of iron layers, were investigated from Rietveld refinements of x-ray diffraction data, collected by step/scan mode. From this refinement lattice constant, a, and sulfur position parameter, u, nearest neighbor Fe–S and S–S bond distances and tetrahedral and octahedral bond angles have been determined. Moreover, sulfur deficit in the samples, surface and volume-weighted crystallite size and microstrains were also obtained. From these data, the influence of temperature and time of sulfuration and sulfur pressure on their structural and microstructural properties has been established. Stoichiometric pyrite thin films are obtained by sulfurating the iron films at low temperatures (Ts ∼ 600–700 K) during short times (ts ∼ 0.5–2 h). These experimental conditions yield films with the highest a, u, Fe–S bond distance, and microstrains, as well as S/Fe ratios about 2.00, i.e., null sulfur vacancies, the smallest S–S bond distances, and crystallite size. Finally, the possible influence of these structural and microstructural characteristics on some physical properties (optical absorption, electrical resistivity …) of the films is discussed.

Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in:El acceso a la versión del editor puede requerir la suscripción del recurso Access to the published version may require subscription ABSTRACT -The demonstration of plasmon-assisted lasing by associating optical gain media with plasmonic nanostructures has led to a new generation of nanophotonic devices with unprecedented performances. However, despite the variety of designs demonstrated so far, the operation of these systems is in most cases limited to a single output wavelength, and some reports on multiline emission refer to mixing single nanolasers with the subsequent limitation in compactness. Here, we show multiline operation from a single plasmon-assisted nonlinear solid-state laser on which a linear chain of Ag nanoparticles is deposited. The system provides lasing at 1.08 µm, which is self-converted to the visible range through different parametric frequency-mixing processes generated at metal-dielectric interfaces. Near infrared and simultaneously green and tunable blue radiation with a sub-wavelength confinement in the direction perpendicular to the nanoparticle chain, are obtained at room temperature in CW regime. The results demonstrate the possibility of multifunctional operation from a single plasmon-assisted laser, and offer new avenues for the development of highly integrable sources of coherent radiation.