circadian rhythm

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Related to diurnal cycle: diurnal rhythm, Circadian cycle

circadian rhythm

n.
A daily rhythmic activity cycle, based on 24-hour intervals, that is exhibited by many organisms.

cir·ca·di·an rhythm

(sər-kā′dē-ən)
A daily cycle of biological activity based on a 24-hour period and influenced by regular variations in the environment, such as the alternation of night and day.
Did You Know? Why do you sometimes wake up on time even if your alarm clock doesn't ring? How do nocturnal animals know when it is time to wake up? It's because you—and most other animals—have a kind of internal clock that controls the cycle of the day's biological activities, such as sleeping and waking. These daily biological activities are known as circadian rhythms because they are influenced by the regular intervals of light and dark in each 24-hour day. While the process underlying circadian rhythm is not completely understood, it is mainly controlled by the release of hormones. The brain regulates the amount of hormone released in response to the information it gets from light-sensitive cells in the eye, called photoreceptors. Circadian rhythms can be disrupted by changes in this daily schedule. For example, biologists have observed that birds exposed to artificial light for a long time sometimes build nests in the fall instead of the spring. In humans who travel long distances by air, the local time of day no longer matches the body's internal clock, causing a condition known as jet lag.

circadian rhythm

The regular recurrence of life activities in 24-hour cycles.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.circadian rhythm - a daily cycle of activity observed in many living organisms
biological time - the time of various biological processes
Translations

cir·ca·di·an rhythm

n. ritmo circadiano, ref. a variaciones rítmicas biológicas en un ciclo de 24 horas.
References in periodicals archive ?
Future astronauts might descend into a hollow, long-frozen lava tube on the Moon to gain shelter from cosmic rays and small impact events, and to moderate the extreme temperature swings (300[degrees]C or 540[degrees]F) that the surface endures over a 29V2-day-long lunar diurnal cycle.
As discussed earlier, one unique feature of ARM cloud radar observations with high temporal resolution is that it allows for examination of detailed cloud vertical structures over the diurnal cycle (e.
Among their topics are a genome-wide analysis of cyanobacterial evolution: the example of Synechococcus, the RNA-seq based transcriptomic analysis of single cyanobacterial cells, transcriptomic and proteomic analysis to understand systems-level properties of diurnal cycle in nitrogen-fixing cyanobacteria, metabolic engineering and systems biology for free fatty acid production in cyanobacteria, and ethanol production in cyanobacteria: the impact of omics of the model organism Synechocystis on yield enhancement.
A comparison of different methods shows that even though the hourly approach is the most precise and is required in specific cases, using minimum and maximum temperature for approximating the diurnal cycle leads to reasonably good results (Reicosky et al.
Contract notice: Service educational assistance and protection at the presidio of functional rehabilitation in diurnal cycle "montessori.
Since the new system is separate from all other lighting controls in the building, a central controller is able to maintain the diurnal cycle for all 48 patient rooms, while six-button keypads were installed in each room that would all be fed with vital power to keep the cycles intact during any power interruption.
On shorter timescales, cloudiness and heavy rainfall over tropical and subtropical South America, associated with convective activity, follow a diurnal cycle (de Angelis et al.
The researchers found that X did not exhibit a diurnal cycle like OH, and that it typically exceeded OH in total concentration--further evidence of a link to the high [H.
To explain the observed diurnal cycles in the surface layer temperature, vertical stratification and chlorophyll a fluorescence distribution, estimation of surface solar radiation fluxes (including diurnal cycle) should be available.