Our object in this paper is to study the antecedents, contents, implications, and impact of a not well-known or appreciated paper by EHRENFEST in 1911 on the essential nature of the different quantum hypotheses in radiation theory. After a careful analysis of EHRENFEST’s notebooks, correspondence, and publications, we conclude that the essential points of EHRENFEST’s paper were not perceived to a large extent, and hence that its implications were not considered thoroughly. Specifically, we show that EHRENFEST contributed significantly to the (...) clarifications of the differences between PLANCK’s and EINSTEIN’s respective quantum hypotheses, as well as to those of the concepts ‘‘discontinuity,’’ ‘‘quantization,’’ and ‘‘corpuscularity.’’. (shrink)

It is generally accepted that, around the turn of the century, GIBBS and EINSTEIN independently developed two equivalent formulations of statistical mechanics. GIBBS version is taken as genuine and rigorous, while EINSTEINs, despite some features which are characteristic of him, is usually considered a not totally satisfactory attempt.It will be shown in the present work that such a picture is oversimplified and requires further nuancing. In fact, there are significant differences, with important implications which have not been sufficiently examined, between (...) the two formulations. Several issues relating to the impact of the two versions will also be addressed. (shrink)

We analyze the evolution of EHRENFEST's thought since he proved the necessity of quanta in 1911 until the formulation of his adiabatic hypothesis in 1914. We argue that his research contributed significantly to the solution of critical problems in quantum physics and led to a rigorous definition of the range of validity of BOLTZMANN's principle.

El Gobierno de España y el Banco Internacional de Reconstrucción y Fomento (BIRF) firmaron en 1971 un Proyecto de colaboración con el objetivo de mejorar el nivel de la investigación agraria mediante tres estrategias fundamentales: a) reestructuración del Instituto Nacional de Investigaciones Agrarias (INIA) para crear Centros especializados por cultivos con ámbito de actuación nacional, b) cambio en la planificación y gestión de la investigación mediante la creación de Programas Nacionales por cultivos y c) formación de 200 investigadores en laboratorios (...) internacionales de prestigio en temas prioritarios para las investigaciones a realizar en los Centros. El presupuesto global del Proyecto fue de 28,2 millones de dólares (equivalentes a unos 204 millones de euros actuales), de los que el BIRF aportó 12,7 millones de dólares en forma de crédito. El proyecto cumplió todos los objetivos fundamentales previstos y provocó un cambio importante en la calidad y orientación de la investigación agraria española, que ha tenido una elevada repercusión científica y socioeconómica, especialmente debido al programa de formación, ya que los otros logros se diluyeron como consecuencia de las transferencias del INIA a las Comunidades Autónomas. (shrink)