purpose: to report a case of posterior ischemic optic neuropathy (pion) following percutaneous nephrolithotomy (pcnl). patient and findings: a 57-year-old male who underwent pcnl because of renal stone was referred due to painless bilateral visual loss to the level of light perception immediately after the operation. the patient had history of diabetes mellitus, hyperlipidemia, and mild anemia....

We consider the sum rule proposed by one of us (SLA), obtained by taking the expectation value of an axial vector commutator in a state with one pion. The sum rule relates the pion decay constant to integrals of pion-pion cross sections, with one pion off the mass shell. We remark that recent data on pionpion scattering allow a precise evaluation of the sum rule. We also discuss the related Adl...

We show how the reaction e-e’+ n-n’y can be used to study the dipion system in states of even charge conjugation (and even angular momentum). In particular, its utility for experimentally investigating an I = 0, J = 0 resonance (e-meson) is discussed in detail. (Submitted to Phys. Rev. ) * Work supported by the U. S. Atomic Energy Commission. t N. S. F. Graduate Fellow. To lowest order in the f...