Breaking Symmetry

The postwar Red Scare and McCarthyism solidified Anderson’s left-of-center politics. He solidified his position at Bell Labs by using the concept of superexchange to explain neutron scattering data from transition metal oxides. He disengaged from Shockley and studied magnetism under the tutelage of Charles Kittel, Conyers Herring, and Gregory Wannier. The Heisenberg model is used to explain ferromagnetism and antiferromagnetism and Anderson’s discovery of spontaneous symmetry breaking in quantum antiferromagnets is described. He spends six months in Japan at the invitation of Ryogo Kubo, teaches magnetism, attends and, at an international conference, learns that he is a bone fide solid-state theoretician.

Breaking Symmetry: Fluctuating Asymmetry and Geometric Morphometrics as Tools for Evaluating Developmental Instability under Diverse Agroecosystems

Fluctuating asymmetry (FA), in contrast with other asymmetries, is the bilateral asymmetry that represents small, random developmental differences between right and left sides. After nearly a century of using traditional morphometrics in the estimation of FA, geometric morphometrics (GM) now provides new insights into the use of FA as a tool, especially for assessing environmental and developmental stress. Thus, it will be possible to assess adaptation to various environmental stressors as particular triggers for unavoidable selection pressures. In this review, we describe measures of FA that use geometric morphometrics, and we include a flow chart of the methodology. We also describe how this combination (GM + FA) has been tested in several agroecosystems. Nutritional stress, temperature, chemical pollution, and population density are known stressors experienced by populations in agroecosystems.