title: The effect of lengthened illumination cycles on littering and upon offsprings' freerunning activity.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000528:radiation effects; D003624:Darkness; D005260:Female; D005298:Fertility / Q000528:radiation effects*; D008027:Light; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000528:radiation effects*; D011830:Radiation Effects