This paper was prepared for the NBER Conference on Organizational Change and Performance Improvement. We gratefully acknowledge funding from POPI, the Program for the Study of the Pharmaceutical Industry at MIT, by the MIT Center for Innovation in Product Development under NSF Cooperative Agreement Number EEC-9529140, and the Sloan Foundation. Stern completed this paper as an NBER Fellow in Hea...

After a century of observations, we still do not know the origin of cosmic rays. I will review the current state of cosmic ray observations at the highest energies, and their implications for proposed acceleration models and secondary astroparticle fluxes. Possible sources have narrowed down with the confirmation of a GZK-like spectral feature. The anisotropy observed by the Pierre Auger Observ...

We discuss candidates for trans-GZK cosmic rays observed in a variety of detectors. Three types of primaries are represented among the abstracts submitted to this meeting: neutrinos causing a Z-burst, protons arising from the decay of ultra-heavy metastable particles and neutrinos within the framework of low scale string-like models of unification. We attempt to evaluate the relative merits of ...