of which overlap with each other) examine this response taking a variety of approaches. thanatology is by no means reducible to a section of forensic science and the notion that it can be is symptomatic of the pathological urge of scientism to force all disciplines into its own procrustean bed. the biological study of death helps explain what happens, physically, to individuals in the moment of dying and during after-death bodily changes, so that extraneous events at the time of death and thereafter can be clarified. in psychiatry and clinical psychology the medical application of psychological principles and therapeutic drugs is also involved; many licensed psychiatrists are required to take courses on thanatology during training. medical ethics is also an important area of study, especially on the issue of euthanasia ('merciful killing') and assisted suicide. but the degree to which any of these is an aspect of thanatology is a matter of opinion depending primarily on how one defines thanatology itself. there is also a branch of thanatology called music thanatology which focuses on the use of "music vigils" to help dying individuals, their families and friends. a vigil consists of one or a team of music thanatologists who visit the dying person. they play the harp most often but can be any gentle instrument like the guitar and sing music based on changes that they observe in that person's physiology as well as in interpersonal family dynamics. the music tends toward the meditative, and can be very helpful to the dying person and others present. often after a vigil, the dying person is more relaxed, less agitated, and in less pain. (however, in the nature of things, appreciative or even disparaging reviews of the service by recipients are few and far between.) some music thanatologists are certified by the music thanatology association international, and they use the initials "cm-th" to designate certification by this professional organization. a number of hospitals and hospices now have professional music thanatologists on their staff.