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Issues relating to causality of bioelectromagnetic effects
Weaver JC, Astumian RD
Electromagnetic Fields 250: 79-96 1995

Significant controversy exists about whether environmental electro-magnetic fields (EMFs) can cause effects in biological systems. EMF interactions have essentially no biochemical specificity, so that competing changes associated with both biological phenomena and intrinsic fluctuations (noise) are extremely important. Only if this competition is successful can effects be attributed to environmental fields. One general approach to assessing causality is based on estimates of a generalized signal-to-noise ratio (S/N). Such estimates have usually considered physical criteria in which the signal is the energy change associated with the environmental field, the background is the energy change due to biologically generated fields, and noise consists of energy fluctuations. More recently the S/N approach has been extended by considering a more biological criterion: changes in the number of molecules in a biochemical pathway. Such criteria can be used to estimate approximate threshold conditions for expecting bioelectromagnetic effects and to identify candidate target tissues.