I. Notions générales. Propriétés nucléaires. a) Introduction Le premier isotope de l’astate, l’astate de nombre de masse 211, a été formé, en 1940 (Corson, MacKenzie et Segré1), par transmutation du bismuth par des rayons α de 32 MeV, selon la réaction nucléaire..

Cosmic Rays have been known for about half a century [1]. The fact that we are only today beginning to understand some of the problems associated with them indicates the order of magnitude of the complexity of the problem, and the degree to which we were dealing with phenomena with which we had little familiarity. Our opinions have gone through a series of changes as we have slowly realized the true nature of the factors involved. For example, in the early 1920’s the general opinion about cosmic rays was that they were of the nature of gamma rays, of some hundreds of Mev’s in energy, and that most of the secondary particles at sea level were electrons. Contrast this with the fact that it has been proved that the majo- rity of primary cosmic rays are protons, with energies tens to thousands of times the previous hundreds of Mev’s, and that the secondary particles reaching sea level are mostly mesons. We see then just how revolutionary has been the change of view which modern detection techniques have made possible.

Foi com estupefacção e profunda dor que recebemos a notícia do falecimento do nosso grande mestre e grande amigo, o Professor D. Miguel A. Catalán. A morte adveio quási sùbitamente, pois ocorreu após uma enfermidade só revelada dois dias antes. Com o seu brusco desaparecimento ficaram brutalmente interrompidas as nossas relações, iniciadas no ano já longínquo de 1933, e desde então mantidas constantemente, não obstante as muitas vicissitudes e contingências a que a vida nos submeteu.

F. C. L. - Curso Geral de Física. 2.o Exame de frequência - Ponto n.o 2 - 1956-57. F. C. L. - Curso Geral de Física. 2.o Exame de frequência - Ponto n.o 3 - 1956.57. Universidade de Edimburgo - Examination for final honours M. A. and B. Sc. final natural Philosophy and Physics III. and IV. - May 1956.

Doutor Manuel Valadares; Doutoramento; I Reunião dos Técnicos Portugueses de Energia Nuclear; Prémio Nobel da Química; Prémio Nobel da Física; Lançamento de satélites artificiais; Nova expedição ao Antárctico; Fusão de núcleos de deutérios; Nobélio;