Axion-like-particle decay in strong electromagnetic backgrounds

The decay of a massive pseudoscalar, scalar and U(1) boson into an electron-positron pair in the presence of strong electromagnetic backgrounds is calculated. Of particular interest is the constant-crossed-field limit, relevant for experiments that aim to measure high-energy axion-like-particle conversion into electron-positron pairs in a magnetic field. The total probability depends on the quantum nonlinearity parameter - a product of field and lightfront momentum invariants. Depending on the seed particle mass, different decay regimes are identified. In the below-threshold case, we find the probability depends on a non-perturbative tunnelling exponent depending on the quantum parameter and the particle mass. In the above-threshold case, we find that when the quantum parameter is varied linearly, the probability oscillates nonlinearly around the spontaneous decay probability. A strong-field limit is identified in which the threshold is found to disappear. In modelling the fall-off of a quasi-constant-crossed magnetic field, we calculate probabilities beyond the constant limit and investigate when the decay probability can be regarded as locally constant.Comment: 22 pages, 7 figure

The Problem of Hylomorphism and Dualism in Avicenna: A Guide to Resolving Other Tensions

One of the greatest challenges posed to the student of Avicenna\u27s psychology is whether he upholds a hylomorphic or dualistic conception of the soul. The hylomorphic position is the one espoused by Aristotle, in nuce that the soul is the entelecheia, or substantial form, of the body considered as matter. The dualistic position is that the soul is a separate substance that controls the body, itself also a substance. The goal of this essay is to determine the full complexity of Avicenna\u27s position, by dissecting four of his great psychological works, each from a different point in his career: The Compendium on the Soul, The Origin and the Return, The De Anima from The Cure, and On the Rational Soul. Ultimately, we contend herein that the method we employ in solving this paper\u27s central problem can serve as a guide to resolving other such problems in Avicenna\u27s philosophy

First Case of Systemic Coronavirus Infection in a Domestic Ferret (Mustela putorius furo) in Peru.

A domestic ferret from Lima, Peru, died after ten days of non-specific clinical signs. Based on pathology, immunohistochemistry and molecular analysis, ferret systemic coronavirus (FRSCV)-associated disease was diagnosed for the first time in South America. This report highlights the potential spread of pathogens by the international pet trade

La nissaga dels organistes Vila i les famílies Vila, Alberch, Ferran i Ferrament de la ciutat de Vic al segle XVI

El prof. J. M. Gregori, autor de una magnifica tesis sobre la música en la catedral de Barcelona durante el siglo XVI, nos presenta en este trabajo 10s resultados de un minuciosa proceso de investigaci6n en torno al famoso organista y compositor Pere Alberch i Vila (1517-1582). A través de 10s cuatro apellidos (Vila, Alberch, Ferran y Ferrament) se han podido datar, como originarios de la ciudad de Vic, cinco organistas que llevaron el apellido Vila, estando evidentemente emparentados; pero dos de ellos, justamente 10s mas conocidos, no se llamaban asi realmente, sino que el apellido Vila les era aplicado como un alias: Pere Alberch i Ferrament, alias ((Vila)) (= Pere Alberch i Vila, 1517-1582, organista de la catedral de Barcelona) y Lluis Ferran i Ferrament, alias ((Vila)) (= Lluis Ferran i Vila, ca. 1561-1631, sobrino del anterior y también organista de la catedral de Barcelona). Los otros miembros de esta estirpe de Vic son Pere Vila (ca. 1465-1538), Pere Vila (ca. 1480-1545) y Pere Ferrament i Vila (ca. 1522-1546). Este documentado estudio complementa las anteriores investigaciones elaboradas por Felip Pedrell, Higini Anglés y Josep Romeu, y precisa, con el concurso de una copiosa documentación biográfica y genealógica, 10s contornos humanos de este importante organista y compositor catalán del siglo XVI

La docència de l'orgue a la primeria del segle XVII a Girona. Notes per a l'estudi de l'acompanyament continu a Catalunya

El contacto entre el organista de Gerona, Joan Martí, y un discípulo suyo, Llatzer Rius, fechado en 1611, pone de manifiesto, mas allá de su puro valor documental, la constatación de la practica del continuo en Cataluña, de la que poseemos pocas noticias aclaratorias a principios del siglo XVII. Posiblemente, tanto el habito anterior como la nueva sistematizaci6n de L. G. da Viadana pesarían sobre ello. En cualquier caso, la aportación trasciende la pequeña circunstancia, incidiendo sobre este importante tema de nuestra historia musical.