Optical pumping of charged excitons in unintentionally doped InAs quantum dots

As an alternative to commonly used electrical methods, we have investigated the optical pumping of charged exciton complexes addressing impurity related transitions with photons of the appropriate energy. Under these conditions, we demonstrate that the pumping fidelity can be very high while still maintaining a switching behavior between the different excitonic species. This mechanism has been investigated for single quantum dots of different size present in the same sample and compared with the direct injection of spectator electrons from nearby donors.Comment: 4 pages and 3 figures submitted to AP

Evidència de recol·lecció de teix (Taxus baccata L.) pels grups neandertals a l'Abric del Pastor (Alcoi, Alacant)

Este artículo presenta la evidencia de fragmentos de tejo (Taxus baccata L.) en el Abric del Pastor, formando parte de la leña utilizada para alimentar las hogueras de los neandertales. Se presenta la distribución actual y prehistórica de este taxón en la Península Ibérica sugiriendo la existencia de áreas donde resistió a los cambios climáticos. Finalmente, se propone el Barranc del Cint como uno de los posibles enclaves refugio

Combustible vegetal y etnografía: estudio de un horno de pan en Ghuala (Argelia)

La maderas y los carbones constituyen un patrimonio biológico y cultural susceptible de ser analizado, tanto en contextos arqueológicos como etnográficos. La antracología, por medio del muestreo del carbón y su identificación botánica, aporta información sobre la interacción constante de los grupos humanos con la vegetación. Se presenta en este artículo un estudio etnográfico realizado en 2012 en Ghuala (Argelia), a través del análisis del combustible leñoso utilizado en un horno de pan tradicional de uso familiar, con el objetivo de arrojar mayor luz al debate existente en torno a las estrategias de gestión del combustible leñoso en las sociedades humanas del pasado

Cueva Maturras (Ciudad Real, España): El papel del fuego en un contexto funerario del III milenio A.C.

Durante las intervenciones arqueológicas en Cueva Maturras se excavó un enterramiento colectivo adscrito al III milenio a.C. con restos de madera carbonizada. Se presentan en este artículo los resultados del análisis de los carbones asociados, aportando datos en el debate existente en la interpretación del papel del fuego en contextos funerarios del Neolítico final e inicios del Calcolítico

Evidència de recol·lecció de teix (Taxus baccata L.)

Aquest article presenta l’evidència de fragments de teix (Taxus baccata L.) a l’Abric del Pastor, que formava part de la llenya utilitzada per a alimentar les fogueres dels neandertals. Es presenta la distribució actual i prehistòrica d’aquest tàxon a la Península Ibèrica i se suggereix l’existència d’àrees on va resistir als canvis climàtics. Finalment, es proposa el Barranc del Cint com un dels possibles enclavaments refugi

Creativitat al servei del futur. El nou impuls de la Nanotecnociència

Creativity at the Service of Future Progress: New Boom in Nanotechnoscience.Currently, a host of research-project applications contain the prefi x nano. However, this could be more-closely related to a new industrial explosion than with the emergence of new conceptual proposals. Society has also been touched by the euphoria that, in some cases, could be called a “craze”- but proposals from the most cautious sectors are far from science fi ction. Among these we fi nd Biomimetics, which takes as a reference point the solutions that living beings have adopted during the evolutionary process. By uniting these technical and academic visions we generate a third more realistic view of these pet hates. Perhaps this is an alternative that provides collective genius creatively and possibly sustainably at the service of future developments

Nano

Transformant el món amb la Nanotecnociènci

Anthracological data from Middle Palaeolithic contexts in Iberia: What do we know?

BSTRACT In this paper, a state of the art regarding the available anthracological data from Middle Palaeolithic contexts in Iberia is presented. The information retrieved is still very scarce and fragmented, as many Iberian areas present palaeobotanical gaps leading to the lack of information regarding local landscape dynamics. The use of different sampling methods to recover wood charcoal remains is a decisive factor which hampers the comparative study, although the dominance of Pinus nigra-sylvestris (black-scots pine) is recorded since, at least, Marine Isotopic Stage 6. This would indicate the widespread presence of cryophilous pine woodlands during the Upper Pleistocene in Iberia pointing to the prevalence of supramediterranean conditions (MAT = 8 - 13 ºC). This state of the art aims to contribute to our understanding of Upper Pleistocene Iberian landscapes based on Neanderthal firewood gathering activities

Exciton Gas Compression and Metallic Condensation in a Single Semiconductor Quantum Wire

We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidences of metallic liquid condensation at low temperatures. Firstly, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Secondly, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at $n_c\sim1\times10^5$ cm$^{-1}$ and $T_c\sim35$ K, respectively.Comment: 4 pages, 5 figure

El majúscul impacte d'allò minúscul

Tininess Makes a Huge Impact: Semiconducting and Metallic Nanoparticles.Defying the conventions of linguistic repetition, the prefi x nano springs up in all languages with unusual force. Nanostructure, nanofi ber, nanocrystals, nanowires, nanotubes, nanodevice ... These are just a few examples, although you won’t fi nd them in the dictionary. These words have retained some meaning of the root from which they are derived, but should inescapably be contemplated, at best, as distant metaphorical refl ections. The words nanoparticle and nanocrystal will be the focus of this article: What are nanoparticles? When is a nanoparticle a nanocrystal? When is the nanoparticle a quantum dot? What applications can we expect if they are semiconducting or metallic