Don Ramón Vega, enigmático rebelde de la ópera mexicana

Resumen: Un fortuito hallazgo del libreto manuscrito de la ópera El grito de Dolores, de Ramón Vega, compositor mexicano del siglo XIX, protagonizado por esta autora, desencadenó una serie de preguntas que hasta el presente no han sido respondidas a cabalidad por los estudios dedicados a la historia de la música en México. La investigación desarrollada con el propósito de situar el manuscrito encontrado en el contexto social y cultural del siglo de la Independencia y la exhaustiva pesquisa realizada en diferentes archivos históricos fructificaron en el descubrimiento de un vasto corpus de fuentes documentales actualmente desconocidas. La información que arrojó el análisis de estos documentos completó el conocimiento existente sobre la vida de Ramón Vega, permitió enderezar algunas ideas falibles en torno a su producción operística, así como construir y sustentar la hipótesis de que El grito de Dolores puede calificarse como el primer intento de creación de una ópera mexicana “enteramente nacional”.

Fusion energy-production from a deuterium-tritium plasma in the jet tokamak

Describes a series of experiments in the Joint European Torus (JET), culminating in the first tokamak discharges in deuterium-tritium fuelled mixture. The experiments were undertaken within limits imposed by restrictions on vessel activation and tritium usage. The objectives were: (i) to produce more than one megawatt of fusion power in a controlled way; (ii) to validate transport codes and provide a basis for accurately predicting the performance of deuterium-tritium plasmas from measurements made in deuterium plasmas; (iii) to determine tritium retention in the torus systems and to establish the effectiveness of discharge cleaning techniques for tritium removal; (iv) to demonstrate the technology related to tritium usage; and (v) to establish safe procedures for handling tritium in compliance with the regulatory requirements. A single-null X-point magnetic configuration, diverted onto the upper carbon target, with reversed toroidal magnetic field was chosen. Deuterium plasmas were heated by high power, long duration deuterium neutral beams from fourteen sources and fuelled also by up to two neutral beam sources injecting tritium. The results from three of these high performance hot ion H-mode discharges are described: a high performance pure deuterium discharge; a deuterium-tritium discharge with a 1% mixture of tritium fed to one neutral beam source; and a deuterium-tritium discharge with 100% tritium fed to two neutral beam sources. The TRANSP code was used to check the internal consistency of the measured data and to determine the origin of the measured neutron fluxes. In the best deuterium-tritium discharge, the tritium concentration was about 11% at the time of peak performance, when the total neutron emission rate was 6.0 × 10¹⁷ neutrons/s. The integrated total neutron yield over the high power phase, which lasted about 2 s, was 7.2 × 10¹⁷ neutrons, with an accuracy of ±7%. The actual fusion amplification factor, Q_DT was about 0.15