Miguel Ángel Martín Sánchez

Electrical stimulation vs thermal effects in a complex electromagnetic environment

Studies linking exposure to low levels of radiofrequencies with adverse health effects, notwithstanding their present apparent inconsistency, have contributed to a steady improvement in the quality of evaluating that exposure. In complex electromagnetic environments, with a multitude of emissions of different frequencies acting simultaneously, knowledge of the spectral content is fundamental to evaluating human exposure to non-ionizing radiation. In the present work, we quantify the most significant spectral components in the frequency band 0.5-2200 MHz in an urban area. The measurements were made with a spectrum analyzer and monopole, biconical, and log-periodic antennas. Power density levels were calculated separately for the medium wave, short wave, and frequency modulation radio broadcasting bands, and for the television and GSM, DCS, and UMTS mobile telephony bands. The measured levels were compared with the ICNIRP reference levels for exposure to multiple frequency sources for thermal effects and electrical stimulation. The results showed the criterion limiting exposure on the basis of preventing electrical stimulation of peripheral nerves and muscles to be stricter (exposure quotient 24.7 10(-4)) than that based on thermal considerations (exposure quotient 0.16 10(-4)). The bands that contribute most to the latter are short wave, with 46.2%, and mobile telephony with 32.6% of the total exposure. In a complex electromagnetic environment, knowledge of the radiofrequency spectrum is essential in order to quantify the contribution of each type of emission to the publics exposure. It is also necessary to evaluate the electrical effects as well as the thermal effects because the criterion to limit exposure on the basis of the effect of the electrical stimulation of tissues is stricter than that based on thermal effects.

La idea de universidad del cardenal John Henry Newman

espanolEl britanico John Henry Newman es uno de los personajes mas influyentes del pensamiento ingles del siglo XIX. Fue uno de conversos mas famosos de los ultimos tiempos, abandonando el anglicanismo en la Inglaterra del XIX y convirtiendose al catolicismo a pesar de las dificultades que eso significaba. Newman fue uno de los mas grandes intelectuales de la epoca, personaje muy influyente en el Movimiento de Oxford y destaco artifice de la fundacion de la Universidad Catolica de Irlanda. Cardenal de la Iglesia Catolica, en sus escritos refleja sus inquietudes intelectuales y educativas. Seran precisamente estas y su idea de universidad, lo que se desarrollara en las paginas que siguen, tratando de ahondar en el pensamiento filosofico y espiritual de Newman, con giros y vinculaciones con sus ideas pedagogicas, las mas olvidadas en los trabajos dedicados al cardenal ingles. EnglishJohn Henry Newman is one of the most influential English 19th century thought. He was one of most famous converts in recent times, leaving Anglicanism in England in the 19th and converting to Catholicism despite the difficulties that meant. Newman was one of the greatest intellectuals of the time, very influential figure in the Oxford Movement and stressed architect of the foundation of the Catholic University of Ireland. Cardinal of the Catholic Church in his writings reflected his intellectual and educational concerns. These are precisely and their idea of university, which will take place in the pages that follow, trying to delve into the philosophical and spiritual thought of Newman, with twists and attachments to their educational ideas, the most neglected in the work dedicated to the English cardinal.