Sobre el origen y difusión del Neolítico en la Península Ibérica, ca. 5600-5000 cal a.C.

Desde la década de los años 90 del pasado s. XX los estudios sobre el Neolítico vivieron una auténtica revolución empírica. Fruto de proyectos de investigación programados e intervenciones de urgencia, se excavaron y dieron a conocer una amplia serie de nuevas estaciones ubicadas dentro y, sobre todo, fuera de las regiones “clásicas”: el área mediterránea peninsular. Esta ampliación de la base documental que incluye también, por primera vez, y de manera destacada a Portugal, debiera permitir la evaluación de los modelos propuestos para explicar la neolitización. Sin embargo, esto no resulta exactamente así. Sabemos que los niveles de los yacimientos prehistóricos distan mucho de ser contextos cerrados

Carl Knappet. An Archaeology of Interaction: Network Perspectives on Material Culture and Society

Carl Knappet. An Archaeology of Interaction: Network Perspectives on Material Culture and Societ

Chiral Symmetry Restoration and the Ultraquantum limit of Axionic Charge Density Waves in Weyl Semimetals

A new mechanism for chiral symmetry restoration at extreme high magnetic fields is proposed in the context of the Magnetic Catalysis scenario in Weyl Semimetals. Contrary to previous proposals, here we show that, at very large magnetic fields, the transverse velocity of the axion field, the phase mode of the chiral condensate $\langle\bar{\psi}\psi\rangle$, becomes effectively one-dimensional and its fluctuations destroy a possible nonzero value of this fermionic condensate. We also show that, despite of the $U(1)$ chiral symmetry is not broken at extremely large magnetic fields, the spectrum of the system is comprised by a well defined gapless bosonic excitation, connected to the axion mode, and a correlated insulating fermionic liquid that is neutral to $U(1)$ chiral transformations. We also discuss some consequences of this theory that can be contrasted to experiments.Comment: 19 pages, 2 figure

Phonon-mediated Hydrodynamic Transport in a Weyl Semimetal

We analyze from a microscopic point of view the feasibility of a hydrodynamic regime in a type-I Weyl semimetal driven by electron-electron interactions mediated by virtual phonons. Considering also the effects of of impurities and the absorption/emission of real phonons, the electric and thermal conductivities are derived. At temperatures $T$ above the Bloch-Gr\"uneisen temperature $T_\textrm{BG}$, virtual phonons behave similarly to real phonons, but the Lorenz ratio is modified by a constant prefactor dependent on the Fermi surface geometry. For temperatures below $T_\textrm{BG}$, processes that do not conserve chirality induce a $T^2$ dependence in the electric resistivity, opening a window where momentum-conserving interactions dominate transport signatures. We quantitatively discuss this hydrodynamic window and put it into context with recent experimental literature on the subject.Comment: 11(Main text)+22(appendix) pages. 3 Fig

An open-source software-defined radio collection for GNSS receivers

The master's thesis has as a main objective to encompass the progress and efforts dedicated to the development and improvement of an open-source collection of Software-Defined Radios (SDR) for Global Navigation Satellite Systems (GNSS). Most of the efforts have focused in conducting an extensive test campaign for each implementation of the collection, with the aim of determining their characteristics at every stage in the positioning process, and make the required adjustments to achieve the defined performance. This document details the structure of the collection, the adjustments made to improve each code-base as well as the metrics considered to assess the obtained results.Outgoin

Technological style, chaîne opératoire, and labor investment of early Neolithic pottery

Se presentan los datos tecnológicos derivados del muestreo del conjunto cerámico del Neolítico antiguo de las comarcas centrales valencianas. A través de ellos se realiza una aproximación al estilo tecnológico a través del concepto de "cadena operativa" al tiempo que se discute el grado de inversión de trabajo en algunas de las producciones específicas que definen este horizonte cultural. Todo ello nos permite, entre otros aspectos, aproximarnos a la relación entre secuenca productiva, tecnología y estilo decorativo

Presentación

Se procede a presentar los resultados del proyecto de investigación concedidos por el MICIM bajo el título de "Cerámica y Estilo", que focalizaba su interés en las primeras producciones cerámicas de los grupos neolíticos peninsulares, durante el VI milenio cal AC