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Circadian rhythm

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A circadian rhythm is any biological process that displays an endogenous, entrainable oscillation of about 24 hours. [1]

140 relations: Actigraphy, Acute kidney injury, Adenosine triphosphate, Advanced sleep phase disorder, Alexander the Great, Androsthenes of Thasos, Animal, ARNTL, ARNTL2, Auguste Forel, Autophagy, Azotemia, Bacterial circadian rhythms, Bipolar disorder, Cell (biology), Charles Czeisler, Chemical kinetics, Chronobiology, Chronotype, Circa, Circadian clock, Circadian rhythm sleep disorder, Circasemidian rhythm, Circaseptan, Cocaine, Cone cell, Conifer cone, Cortisol, Cryptochrome, Cyanobacteria, Delayed sleep phase disorder, Derk-Jan Dijk, Diabetes mellitus, Diurnal cycle, Diurnality, Drosophila, Endogeny (biology), Entrainment (chronobiology), Epigenetics, Epithalamus, Esophagus, Fatigue (medical), Franz Halberg, Free-running sleep, Fungus, Gene D. Block, Great Oxygenation Event, Ground squirrel, Harvard University, Hormone, ..., Human body temperature, Human eye, Human spaceflight, Hyperoxia, Hypothalamus, Hypoxia (medical), Illuminance, Ingeborg Beling, Insomnia, Intrinsically photosensitive retinal ganglion cells, Jean-Jacques d'Ortous de Mairan, Jet lag, Joseph Takahashi, Latin, Light effects on circadian rhythm, Light in school buildings, Liver, Lung, Mammal, Mars, Melanopsin, Melatonin, Metabolism, Metabolite, Mimosa pudica, Monarch butterfly, Nathaniel Kleitman, National Transportation Safety Board, Neural oscillation, Nocturnality, Non-24-hour sleep–wake disorder, Obesity, Oxidative stress, Pancreas, PER1, PER2, PER3, Period (gene), Phase response curve, Photoperiodism, Photoreceptor cell, Physiology, Pineal gland, Plant, Polyphagia, Polyphasic sleep, Porcupine, Power nap, Prokaryote, Q10 (temperature coefficient), Quail, Reactive oxygen species, Redox, Reindeer, Repressilator, Reticular activating system, Retina, Retinohypothalamic tract, Rev-ErbA alpha, Rock ptarmigan, Rod cell, Ron Konopka, Segmented sleep, Seymour Benzer, Shift work, Sleep architecture, Sleep disorder, Sleep onset latency, Sodium-vapor lamp, Solar time, Spalax, Spleen, Stefania Follini, Stem cell, Suprachiasmatic nucleus, Svalbard, Tamarind, Thymus, Tide, Time zone, TOC1 (gene), Ultradian rhythm, Ultraviolet, Unfolded protein response, University of Tromsø, Uremia, Zeitgeber, 5th Projekt, 70th parallel north, 78th parallel north. Expand index (90 more) »


Actigraphy is a non-invasive method of monitoring human rest/activity cycles.

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Acute kidney injury

Acute kidney injury (AKI), previously called acute renal failure (ARF), is an abrupt loss of kidney function that develops within 7 days.

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Adenosine triphosphate

Adenosine triphosphate (ATP) is a nucleoside triphosphate used in cells as a coenzyme often called the "molecular unit of currency" of intracellular energy transfer.

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Advanced sleep phase disorder

Advanced sleep phase disorder (ASPD), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder or advanced sleep phase syndrome (ASPS), is a condition in which patients feel very sleepy and go to bed early in the evening (e.g. 6:00–8:00 p.m.) and wake up very early in the morning (e.g. around 3:00 a.m.).

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Alexander the Great

Alexander III of Macedon (20/21 July 356 BC – 10/11 June 323 BC), commonly known as Alexander the Great (Ἀλέξανδρος ὁ Μέγας, Aléxandros ho Mégas, from the Greek ἀλέξω (alexō) "defend" and ἀνδρ- (andr-), the stem of ἀνήρ (anēr) "man" and means "protector of men") was a King (Basileus) of the Ancient Greek kingdom of Macedon;;;;;;;;;;;;;;;;;;. and a member of the Argead dynasty, a famous ancient Greek royal house.

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Androsthenes of Thasos

Androsthenes son of Callistratus, from Thasos, who had been settled in Amphipolis, was admiral of Alexander the Great.

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Animals are multicellular, eukaryotic organisms of the kingdom Animalia (also called Metazoa).

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Aryl hydrocarbon receptor nuclear translocator-like protein 1 is protein that in humans is encoded by the ARNTL gene also known as Bmal, Mop3, TIC, JAP3, PASD3, Bmal1c, bHLHe5.

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Aryl hydrocarbon receptor nuclear translocator-like 2, also known as Mop9, Bmal2, Clif, or Arntl2, is a gene.

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Auguste Forel

Auguste-Henri Forel (September 1, 1848 – July 27, 1931) was a Swiss myrmecologist, neuroanatomist, psychiatrist and eugenicist, notable for his investigations into the structure of the human brain and that of ants.

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Autophagy (or autophagocytosis) (from the Greek auto-, "self" and phagein, "to eat"), is the natural, destructive mechanism that disassembles, through a regulated process, unnecessary or dysfunctional cellular components.

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Azotemia (azot, "nitrogen" + -emia, "blood condition") is a medical condition characterized by abnormally high levels of nitrogen-containing compounds (such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds) in the blood.

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Bacterial circadian rhythms

Bacterial circadian rhythms, like other circadian rhythms, are endogenous "biological clocks" that have the following three characteristics: (a) in constant conditions (i.e. constant temperature and either constant light or constant darkness) they oscillate with a period that is close to, but not exactly, 24 hours in duration, (b) this "free-running" rhythm is temperature compensated, and (c) the rhythm will entrain to an appropriate environmental cycle.

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Bipolar disorder

Bipolar disorder, also known as bipolar affective disorder and manic-depressive illness, is a mental disorder characterized by periods of elevated mood and periods of depression.

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Cell (biology)

The cell (from Latin cella, meaning "small room") is the basic structural, functional, and biological unit of all known living organisms.

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Charles Czeisler

Charles A. Czeisler is an American physician and sleep researcher, born in Chicago, Illinois in 1952.

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Chemical kinetics

Chemical kinetics, also known as reaction kinetics, is the study of rates of chemical processes.

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Chronobiology is a field of biology that examines periodic (cyclic) phenomena in living organisms and their adaptation to solar- and lunar-related rhythms.

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Chronotype refers to the behavioral manifestation of underlying circadian rhythms of myriad physical processes.

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Circa, usually abbreviated c., ca or ca. (also circ. or cca.), means "approximately" in several European languages including English, usually in reference to a date.

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Circadian clock

The circadian clock, or circadian oscillator, in most living things makes it possible for organisms to coordinate their biology and behavior with daily environmental changes in the day-night cycle.

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Circadian rhythm sleep disorder

Circadian rhythm sleep disorders (CRSD) are a family of sleep disorders affecting, among other things, the timing of sleep.

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Circasemidian rhythm

Numerous studies have demonstrated that human circadian rhythms in many measures of performance and physiological activity actually have a 2-peak daily (circasemidian) pattern.

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A circaseptan rhythm is a cycle consisting of 7 days in which many biological processes of life resolve.

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Cocaine, also known as benzoylmethylecgonine or coke, is a strong stimulant mostly used as a recreational drug.

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Cone cell

Cone cells, or cones, are one of two types of photoreceptor cells in the retina of the eye.

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Conifer cone

A cone (in formal botanical usage: strobilus, plural strobili) is an organ on plants in the division Pinophyta (conifers) that contains the reproductive structures.

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Cortisol is a steroid hormone, in the glucocorticoid class of hormones, and is produced in humans by the zona fasciculata of the adrenal cortex within the adrenal gland.

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Cryptochromes (from the Greek κρυπτό χρώμα, hidden colour) are a class of flavoproteins that are sensitive to blue light.

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Cyanobacteria, also known as Cyanophyta, is a phylum of bacteria that obtain their energy through photosynthesis.

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Delayed sleep phase disorder

Delayed sleep-phase disorder (DSPD), also known as delayed sleep-phase syndrome (DSPS) or delayed sleep-phase type (DSPT), and in the 2014 revision of the International Classification of Sleep Disorders (ISCD-3), delayed sleep-wake phase disorder, is a dysregulation of a person's circadian rhythm (biological clock), compared to the general population and relative to societal norms.

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Derk-Jan Dijk

Derk-Jan Dijk (born 1958 in Zwollerkerspel, Netherlands) is a researcher of sleep and circadian rhythms.

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Diabetes mellitus

Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic diseases in which there are high blood sugar levels over a prolonged period.

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Diurnal cycle

A diurnal cycle is any pattern that recurs every 24 hours as a result of one full rotation of the Earth with respect to the Sun.

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Diurnality is a plant or animal behavior characterized by activity during the day and sleeping, or other inactivity, at night.

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Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit.

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Endogeny (biology)

Endogenous substances and processes are those that originate from within an organism, tissue, or cell.

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Entrainment (chronobiology)

Entrainment, within the study of chronobiology, occurs when rhythmic physiological or behavioral events match their period and phase to that of an environmental oscillation.

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Epigenetics is the study, in the field of genetics, of cellular and physiological phenotypic trait variations that are caused by external or environmental factors that switch genes on and off and affect how cells read genes instead of being caused by changes in the DNA sequence.

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The epithalamus is a (dorsal) posterior segment of the diencephalon.

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The esophagus (American English) or oesophagus (British English), commonly known as the foodpipe or gullet, is an organ in vertebrates which consists of a fibromuscular tube through which food passes, aided by peristaltic contractions, from the pharynx to the stomach.

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Fatigue (medical)

Fatigue (also called exhaustion, tiredness, languidness, languor, lassitude, and listlessness) is a subjective feeling of tiredness which is distinct from weakness, and has a gradual onset.

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Franz Halberg

Franz Halberg (July 5, 1919 – June 9, 2013) was a scientist and one of the founders of modern chronobiology.

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Free-running sleep

Free-running sleep experiments can involve any organism which sleeps.

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A fungus (plural: fungi or funguses) is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms known as mushrooms.

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Gene D. Block

Gene David Block (born August 17, 1948) is an American biologist, academic, inventor, and chancellor of the University of California, Los Angeles.

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Great Oxygenation Event

The Great Oxygenation Event (GOE), also called the Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust, Oxygen Revolution, or Great Oxidation, was the biologically induced appearance of dioxygen (O2) in Earth's atmosphere.

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Ground squirrel

The ground squirrels are members of the squirrel family of rodents (Sciuridae) which generally live on or in the ground, rather than trees.

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Harvard University

Harvard University is a private Ivy League research university in Cambridge, Massachusetts, established in 1636.

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A hormone (from Greek ὁρμή, "impetus") is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.

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Human body temperature

Normal human body temperature, also known as normothermia or euthermia, depends upon the place in the body at which the measurement is made, the time of day, as well as the activity level of the person.

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Human eye

The human eye is an organ that reacts to light and has several purposes.

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Human spaceflight

Human spaceflight (also referred to as manned spaceflight) is space travel with a crew aboard the spacecraft.

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Hyperoxia occurs when tissues and organs are exposed to an excess supply of oxygen (O2) or higher than normal partial pressure of oxygen.

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The hypothalamus (from Greek ὑπό, "under" and θάλαμος, "room, chamber") is a portion of the brain that contains a number of small nuclei with a variety of functions.

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Hypoxia (medical)

Hypoxia (also known as hypoxiation or anoxemia) is a condition in which the body or a region of the body is deprived of adequate oxygen supply.

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In photometry, illuminance is the total luminous flux incident on a surface, per unit area.

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Ingeborg Beling

Ingeborg Beling was a German ethologist from the early 20th century who worked in the field of chronobiology.

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Insomnia, or trouble sleeping, is a sleep disorder in which there is an inability to fall asleep or to stay asleep as long as desired.

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Intrinsically photosensitive retinal ganglion cells

Intrinsically photosensitive Retinal Ganglion Cells (ipRGCs), also called photosensitive Retinal Ganglion Cells (pRGC), or melanopsin-containing retinal ganglion cells, are a type of neuron (nerve cell) in the retina of the mammalian eye.

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Jean-Jacques d'Ortous de Mairan

Jean-Jacques d'Ortous de Mairan (26 November 1678 – 20 February 1771) was a French geophysicist, astronomer and most notably, chronobiologist, was born in the town of Béziers on 26 November 1678.

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Jet lag

Jet lag, medically referred to as desynchronosis and rarely as circadian dysrhythmia, is a physiological condition which results from alterations to the body's circadian rhythms resulting from rapid long-distance transmeridian (east–west or west–east) travel on high-speed aircraft.

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Joseph Takahashi

Joseph S. Takahashi is a Japanese American neurobiologist and geneticist.

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Latin (Latin: lingua latīna) is a classical language belonging to the Italic branch of the Indo-European languages.

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Light effects on circadian rhythm

Most animals and other organisms have "built in clocks" in their brains that regulate the timing of biological processes and daily behavior.

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Light in school buildings

Light in school buildings traditionally is from a combination of daylight and electric light to illuminate classrooms, hallways, cafeterias, offices and other interior areas.

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The liver is a vital organ of vertebrates and some other animals.

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The lung is the essential respiratory organ in many air-breathing animals, including most tetrapods, a few fish and a few snails.

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Mammals (class Mammalia from Latin mamma "breast") are any members of a clade of endothermic amniotes distinguished from reptiles and birds by the possession of hair, three middle ear bones, mammary glands, and a neocortex (a region of the brain).

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Mars is the fourth planet from the Sun and the second smallest planet in the Solar System, after Mercury.

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Melanopsin is a type of photopigment belonging to a larger family of light-sensitive retinal proteins called opsins and encoded by the gene Opn4.

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Melatonin, chemically N-acetyl-5-methoxytryptamine, is a substance found in animals, plants, fungi and bacteria.

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Metabolism (from μεταβολή metabolē, "change") is the set of life-sustaining chemical transformations within the cells of living organisms.

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Metabolites are the intermediates and products of metabolism.

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Mimosa pudica

Mimosa pudica (from pudica "shy, bashful or shrinking"; also called sensitive plant, sleepy plant or shy plant) is a creeping annual or perennial herb of the pea family Fabaceae often grown for its curiosity value: the compound leaves fold inward and droop when touched or shaken, defending themselves from harm, and re-open a few minutes later.

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Monarch butterfly

The monarch butterfly or simply monarch (Danaus plexippus) is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae.

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Nathaniel Kleitman

Nathaniel Kleitman (April 26, 1895 Kishinev – August 13, 1999 Los Angeles) was a physiologist and sleep researcher who served as Professor Emeritus in Physiology at the University of Chicago.

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National Transportation Safety Board

The National Transportation Safety Board (NTSB) is an independent U.S. government investigative agency responsible for civil transportation accident investigation.

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Neural oscillation

Neural oscillation is rhythmic or repetitive neural activity in the central nervous system.

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Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day.

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Non-24-hour sleep–wake disorder

Non-24-hour sleep–wake disorder (non-24), is one of several types of chronic circadian rhythm sleep disorders (CRSDs).

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Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health, leading to reduced life expectancy and/or increased health problems.

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Oxidative stress

Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage.

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The pancreas is a glandular organ in the digestive system and endocrine system of vertebrates.

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The PER1 gene encodes the period circadian protein homolog 1 protein in humans.

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PER2 is a protein in mammals encoded by the PER2 gene.

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The PER3 gene encodes the period circadian protein homolog 3 protein in humans.

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Period (gene)

Period (per) is a gene located on the X chromosome of Drosophila melanogaster.

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Phase response curve

A phase response curve (PRC) illustrates the transient change in the cycle period of an oscillation induced by a perturbation as a function of the phase at which it is received.

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Photoperiodism is the physiological reaction of organisms to the length of day or night.

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Photoreceptor cell

A photoreceptor cell is a specialized type of neuron found in the retina that is capable of phototransduction.

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Physiology is the scientific study of the normal function in living systems.

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Pineal gland

The pineal gland, also known as the pineal body, conarium or epiphysis cerebri, is a small endocrine gland in the vertebrate brain.

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Plants, also called green plants, are multicellular eukaryotes of the kingdom Plantae.

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Polyphagia or hyperphagia refers to excessive hunger or increased appetite.

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Polyphasic sleep

Polyphasic sleep is the practice of sleeping multiple times in a 24-hour period—usually more than two, in contrast to biphasic sleep (twice per day) or monophasic sleep (once per day).

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Porcupines are rodents with a coat of sharp spines, or quills, that protect against predators.

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Power nap

A power nap is a short sleep which terminates before the occurrence of deep sleep or slow-wave sleep (SWS), intended to quickly revitalize the subject.

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A prokaryote is a single-celled organism that lacks a membrane-bound nucleus (karyon), mitochondria, or any other membrane-bound organelle.

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Q10 (temperature coefficient)

The Q10 temperature coefficient is a measure of the rate of change of a biological or chemical system as a consequence of increasing the temperature by 10 °C.

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Quail is a collective name for several genera of mid-sized birds generally placed in the order Galliformes.

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Reactive oxygen species

Reactive oxygen species (ROS) are chemically reactive molecules containing oxygen.

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Redox reactions include all chemical reactions in which atoms have their oxidation state changed; in general, redox reactions involve the transfer of electrons between species.

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The reindeer (Rangifer tarandus), also known as caribou in North America, is a species of deer with circumpolar distribution, native to Arctic, Subarctic, tundra, boreal and mountainous regions of northern Europe, Siberia, and North America.

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The repressilator is a synthetic genetic regulatory network reported in a paperA Synthetic Oscillatory Network of Transcriptional Regulators; Michael Elowitz and Stanislas Leibler; Nature.

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Reticular activating system

The reticular activating system (RAS), or extrathalamic control modulatory system, is a set of connected nuclei in the brains of vertebrates that is responsible for regulating wakefulness and sleep-wake transitions.

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The retina (pl. retinae,; from Latin rēte, meaning "net") is the third and inner coat of the eye which is a light-sensitive layer of tissue.

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Retinohypothalamic tract

The retinohypothalamic tract (RHT) is a photic neural input pathway involved in the circadian rhythms of mammals.

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Rev-ErbA alpha

Rev-ErbA alpha also known as NR1D1 (nuclear receptor subfamily 1, group D, member 1), is a protein that in humans is encoded by the NR1D1 gene.

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Rock ptarmigan

The rock ptarmigan (Lagopus muta) is a medium-sized gamebird in the grouse family.

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Rod cell

Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than the other type of visual photoreceptor, cone cells.

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Ron Konopka

Ronald J. Konopka is a former American geneticist who studied chronobiology.

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Segmented sleep

Segmented sleep, also known as divided sleep, bimodal sleep pattern, bifurcated sleep, or interrupted sleep, is a polyphasic sleep or biphasic sleep pattern where two or more periods of sleep are punctuated by periods of wakefulness.

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Seymour Benzer

Seymour Benzer (October 15, 1921 – November 30, 2007) was an American physicist, molecular biologist and behavioral geneticist.

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Shift work

Shift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of the week (abbreviated as 24/7).

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Sleep architecture

Sleep architecture describes the structure and pattern of sleep and encompasses several variables.

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Sleep disorder

A sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal.

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Sleep onset latency

In sleep science, sleep onset latency (SOL) is the length of time that it takes to accomplish the transition from full wakefulness to sleep, normally to the lightest of the non-REM sleep stages.

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Sodium-vapor lamp

A sodium-vapor lamp is a gas-discharge lamp that uses sodium in an excited state to produce light.

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Solar time

Solar time is a reckoning of the passage of time based on the Sun's position in the sky.

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The genus Spalax contains the blind, fossorial, or subterranean mole-rats, which are one of several types of rodents that are called mole-rats.

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The spleen (from Greek σπλήν—splḗn) is an organ found in virtually all vertebrates.

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Stefania Follini

Stefania Follini (born on the 16th of August, 1961) is an Italian interior designer.

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Stem cell

Stem cells are undifferentiated biological cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells.

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Suprachiasmatic nucleus

The suprachiasmatic nucleus or nuclei (SCN) is a tiny region located in the hypothalamus, situated directly above the optic chiasm.

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Svalbard (formerly known by its Dutch name Spitsbergen) is a Norwegian archipelago in the Arctic Ocean.

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Tamarind (Tamarindus indica) (from تمر هندي, romanized tamar hindi, "Indian date") is a leguminous tree in the family Fabaceae indigenous to tropical Africa.

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The thymus is a specialized primary lymphoid organ of the immune system.

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Tides are the rise and fall of sea levels caused by the combined effects of gravitational forces exerted by the Moon, Sun, and rotation of the Earth.

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Time zone

A time zone is a region that observes a uniform standard time for legal, commercial, and social purposes.

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TOC1 (gene)

Timing of CAB expression 1 is a protein that in Arabidopsis thaliana is encoded by the TOC1 gene.

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Ultradian rhythm

An ultradian rhythm is a recurrent period or cycle repeated throughout a 24-hour circadian day.

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Ultraviolet (UV) light is an electromagnetic radiation with a wavelength from 400 nm to 100 nm, shorter than that of visible light but longer than X-rays.

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Unfolded protein response

The unfolded protein response (UPR) is a cellular stress response related to the endoplasmic reticulum (ER).

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University of Tromsø

The University of Tromsø - The Arctic University of Norway (Universitetet i Tromsø – Norges arktiske universitet; is the world's northernmost university. Located in the city of Tromsø, Norway, it was established in 1968, and opened in 1972. It is one of eight universities in Norway. The University of Tromsø is the largest research and educational institution in northern Norway. The University's location makes it a natural venue for the development of studies of the region's natural environment, culture, and society. The main focus of the University's activities is on the Auroral light research, Space science, Fishery science, Biotechnology, Linguistics, Multicultural societies, Saami culture, Telemedicine, epidemiology and a wide spectrum of Arctic research projects. The close vicinity of the Norwegian Polar Institute, the Norwegian Institute of Marine Research and the Polar Environmental Centre gives Tromsø added weight and importance as an international centre for Arctic research. Research activities, however, are not limited to Arctic studies. The University researchers work within a broad range of subjects and are recognised both nationally and internationally. On January 1, 2009 the University of Tromsø merged with Tromsø University College. On August 1, 2013 the university merged with Finnmark University College to form Universitetet i Tromsø – Norges arktiske universitet (The University of Tromsø – The Arctic University of Norway), thereby adding campuses in Alta, Hammerfest and Kirkenes.

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Uremia or uraemia (see spelling differences) can be translated as "urea in the blood".

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A zeitgeber is any external or environmental cue that entrains or synchronizes an organism's biological rhythms to the Earth's 24-hour light/dark cycle and 12 month cycle.

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5th Projekt

5th Projekt are a cinematic rock ensemble from Toronto, Canada.

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70th parallel north

The 70th parallel north is a circle of latitude that is 70 degrees north of the Earth's equatorial plane, in the Arctic.

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78th parallel north

The 78th parallel north is a circle of latitude that is 78 degrees north of the Earth's equatorial plane, in the Arctic.

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[1] https://en.wikipedia.org/wiki/Circadian_rhythm

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