Historically it has been shown repeatedly that single high doses of radiation do not allow a therapeutic differential between tumor and critical normal tissues but dose fractionation does. The purpose of conventional dose fractionation is to increase dose to the tumor while preserving normal tissue function. Tumors are generally irradiated with 2Gy dose per fraction delivered daily to a more or...

Robustness has been studied through the analysis of data sets, simulations, and a variety of experimental techniques that each have their own limitations but together confirm the ubiquity of biological robustness. Recent trends suggest that different types of perturbation (e.g., mutational, environmental) are commonly stabilized by similar mechanisms, and system sensitivities often display a lo...

Biological psychiatry has not yet produced clinically viable biomarkers for any of the major psychiatric diseases, and the past 25 years have not brought any fundamentally new biological treatment principles. I discuss reasons for this slow progress and suggest avenues for the development of biomarkers and the discovery of new treatment targets.

Psychiatric genetics, which is growing in size and influence within psychiatry, employs four major research paradigms: 1) basic genetic epidemiology, 2) advanced genetic epidemiology, 3) gene finding methods, and 4) molecular genetics. Paradigms 1 and 2 study aggregate genetic risk factors inferred from patterns of resemblance in relatives. Paradigms 3 and 4 study individual susceptibility gene...