therapy and melatonin administration have been explored by alfred j. lewy (ohsu), josephine arendt (university of surrey, uk) and other researchers as a means to reset animal and human circadian rhythms. additionally, the presence of low-level light at night accelerates circadian re-entrainment of hamsters of all ages by 50%; this is thought to be related to simulation of moonlight. in the second half of 20th century, substantial contributions and formalizations have been made by europeans such as jürgen aschoff and colin pittendrigh, who pursued different but complementary views on the phenomenon of entrainment of the circadian system by light (parametric, continuous, tonic, gradual vs. nonparametric, discrete, phasic, instantaneous, respectively). chronotypes humans can have a propensity to be morning people or evening people; these behavioral preferences are called chronotypes for which there are various assessment questionnaires and biological marker correlations. mealtimes there is also a food-entrainable biological clock, which is not confined to the suprachiasmatic nucleus. the location of this clock has been disputed. working with mice, however, fuller et al. concluded that the food-entrainable clock seems to be located in the dorsomedial hypothalamus. during restricted feeding, it takes over control of such functions as activity timing, increasing the chances of the animal successfully locating food resources. diurnal patterns on the internet in 2018 a study published in plos one showed how 73 psychometric indicators measured on twitter content follow a diurnal pattern. a followup study appeared on chronobiology international in 2021 showed that these patterns were not disrupted by the 2020 uk lockdown. modulators of circadian rhythms in 2021, scientists reported the development of a light-responsive days-lasting modulator of circadian rhythms of tissues via ck1 inhibition. such modulators may be useful for chronobiology research and repair of organs that are "out of sync". other fields chronobiology is an interdisciplinary field of investigation. it interacts with medical and other research fields such as sleep medicine, endocrinology, geriatrics, sports medicine, space medicine and photoperiodism.