Physicists Maria Goeppert Mayer and J. Hans D. Jensen develop a theory of the nucleus as composed of shells of protons and neutrons. It explains why nuclei with certain “magic numbers” of protons and ...

Heavier nuclei are less stable—that’s something we all learned in school. Adding more nucleons (protons and neutrons) makes atoms more likely to break apart. It’s one reason why elements heavier than ...

The nuclear shell model of the atomic nucleus, more than 70 years old, stays firmly in place now that researchers from CERN’s nuclear physics facility ISOLDE have shown that the series of magic ...

Drug-paired conditioned reinforcers can maintain persistent instrumental responding, thus providing a model of some aspects of long-term drug addiction. The purpose of the present study was to ...