Universidad y Ciencia Básica

La conferencia del profesor Dr. Glenn T. Seaborg, sobre “Universidad y Ciencia Básica” que he traducido del original inglés, fue dictada por el mismo con motivo de serle otorgada la medalla Perkin de 1957, por sus múltiples y notables contribuciones originales a la física y la química modernas. La misma fue publicada en la Revista Chemistry and Industry, del 2 de marzo de 1957. El profesor Glenn T. Seaborg es uno de los más famosos físico-químicos nucleares del mundo. En 1951 recibió el Premio Nobel de Química compartido con su colega el profesor Dr. Edwin McMillan por ser ambos los que descubrieron y aislaron dos elementos transuránicos: neptunio y plutonio, en el Laboratorio de Radiación del Departamento de Física de la Universidad de California, de Berkeley. (palabras del traductor)Universidad Nacional de La Plat

The Ion-Exchange Separation of Zirconium and Hafnium

In the course of a rather cursory examination of the elution of tetra-positive ions from the cation exchange resin Dowex 50 with hydrochloric acid solutions, the authors have discovered a very effective method of separating zirconium from hafnimu. In view of the great labor involved in preparing even reasonably pure hafnium compounds by existing methods, they feel that this procedure will prove very valuable to those interested in obtaining hafnium compounds free of zirconium. Although the conditions which give satisfactory separation were first worked out using microgram amounts of material and the radioactive tracer technique, the run described here, involving milligrams of material, illustrates the applicability of the method to the production of significant amounts of pure hafnium and zirconium

Spallation-Fission Competition in Heaviest Elements; Helium IonInduced Reactions in Plutonium Isotopes

Excitation functions have been determined for the spallation and fission reactions induced in plutonium isotopes by 20 to 50 Mev helium ions. The method employed consisted of cyclotron bombardments of plutonium oxide followed by the chemical isolation and alpha or beta counting of radioactive reaction products. Formation cross sections are given where possible for the curium and americium spallation products corresponding to ({alpha},n), ({alpha},2n), ({alpha},3n), ({alpha},4n), ({alpha}5n), ({alpha},p), ({alpha},pn or d), ({alpha},p2n or t), and ({alpha},p3n) reactions in Pu{sup 238} , Pu{sup 239}, and Pu{sup 242}. Fission yield curves and fission cross sections for Pu{sup 238} and Pu{sup 239} serve to define the characteristics of the ({alpha},f) reaction for plutonium isotopes. Chemical procedures are outlined for the separation of both spallation and fission product elements in a sequence of operations performed on the entire dissolved target

Protest Cycles and Political Process: American Peace Movements in the Nuclear Age

Since the dawn of the nuclear age small groups of activists have consistently protested both the content of United States national security policy, and the process by which it is made. Only occasionally, however, has concern about nuclear weapons spread beyond these relatively marginal groups, generated substantial public support, and reached mainstream political institutions. In this paper, I use histories of peace protest and analyses of the inside of these social movements and theoretical work on protest cycles to explain cycles of movement engagement and quiescence in terms of their relation to external political context, or the "structure of political opportunity." I begin with a brief review of the relevant literature on the origins of movements, noting parallels in the study of interest groups. Building on recent literature on political opportunity structure, I suggest a theoretical framework for understanding the lifecycle of a social movement that emphasizes the interaction between activist choices and political context, proposing a six-stage process through which challenging movements develop. Using this theoretical framework I examine the four cases of relatively broad antinuclear weapons mobilization in postwar America. I conclude with a discussion of movement cycles and their relation to political alignment, public policy, and institutional politics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68552/2/10.1177_106591299304600302.pd

The Transcalifornium Elements

During the past sixty years, four elements beyond californium on the atomic number scale have been synthesized by the transmutation of lighter elements. The first preparation of einsteinium and fermium occurred in a thermonuclear explosion. Mendelevium and element 102, however, were prepared by a more conventional method, that of charged particle bombardment of elements of high atomic number