polynomial expansion, in order to show the periodic behavior of the data In chronobiology, an<unk>  is a recurrent period or cycle repeated throughout a 24-hour day. In contrast, circadian<unk> s complete one cycle daily, while infradian<unk> s such as the human menstrual cycle have periods longer than a day. The Oxford English Dictionary's definition of<unk>  specifies that it refers to cycles with a period shorter than a day but longer than an hour. The descriptive term<unk>  is used in sleep research in reference to the 90–120 minute cycling of the sleep stages during human sleep. There is a circasemidian<unk>  in body temperature and cognitive function which is technically<unk> . However, this appears to be the first harmonic of the circadian<unk>  of each and not an endogenous<unk>  with its own<unk>  generator. Other<unk> s include blood circulation, blinking, pulse, hormonal secretions such as growth hormone, heart rate, thermoregulation, micturition, bowel activity, nostril dilation, appetite, and arousal.<unk> s of appetite require antiphasic release of neuropeptide Y (NPY) and corticotropin-releasing hormone (CRH), stimulating and inhibiting appetite<unk> s. Recently,<unk> s of arousal lasting approximately 4 hours were attributed to the dopaminergic system in mammals. When the dopaminergic system is perturbed either by use of drugs or by genetic disruption, these 4 hours<unk> s can lengthen significantly into the infradian (> 24 h) range, sometimes even lasting for days (> 110 h) when methamphetamines are provided.<unk>  mood states in bipolar disorder cycle much faster than rapid cycling; the latter is defined as four or more mood episodes in one year, sometimes occurring within a few weeks.<unk>  mood cycling is characterized by cycles shorter than 24 hours.
Ultradian rhythm
Infradian rhythm
Ventricular escape beat
Junctional rhythm
Junctional escape beat
Electrical alternans
Paroxysmal tachycardia
Atopy