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  2. Dynastic cycle - Wikipedia

    en.wikipedia.org/wiki/Dynastic_cycle

    Dynastic cycle (traditional Chinese: 朝代循環; simplified Chinese: 朝代循环; pinyin: Cháodài Xúnhuán) is an important political theory in Chinese history. According to this theory, each dynasty of China rises to a political, cultural, and economic peak and then, because of moral corruption, declines, loses the Mandate of Heaven ...

  3. Basic rest–activity cycle - Wikipedia

    en.wikipedia.org/wiki/Basic_rest–activity_cycle

    The basic rest–activity cycle (BRAC) is a physiological arousal mechanism in humans proposed by Nathaniel Kleitman, [1] hypothesized to occur during both sleep and wakefulness. Empirically, it is an ultradian rhythm of approximately 90 minutes (80–120 minutes [ 2 ] ) characterized by different levels of excitement and rest.

  4. Early Dynastic Period (Egypt) - Wikipedia

    en.wikipedia.org/wiki/Early_Dynastic_Period_(Egypt)

    The Early Dynastic Period, also known as Archaic Period or the Thinite Period (from Thinis, the hometown of its rulers), [1] is the era of ancient Egypt that immediately follows the unification of Upper and Lower Egypt in c. 3150 BC.

  5. Sleep cycle - Wikipedia

    en.wikipedia.org/wiki/Sleep_cycle

    The sleep cycle is an oscillation between the slow-wave and REM (paradoxical) phases of sleep. It is sometimes called the ultradian sleep cycle, sleep–dream cycle, or REM-NREM cycle, to distinguish it from the circadian alternation between sleep and wakefulness. In humans, this cycle takes 70 to 110 minutes (90 ± 20 minutes). [1]

  6. Randy Gardner sleep deprivation experiment - Wikipedia

    en.wikipedia.org/wiki/Randy_Gardner_sleep...

    Randy Gardner (born c. 1946) is an American man from San Diego, California, who once held the record for the longest amount of time a human has gone without sleep.In December 1963/January 1964, 17-year-old Gardner stayed awake for 11 days and 24 minutes (264.4 hours), breaking the previous record of 260 hours held by Tom Rounds.

  7. Sleep and metabolism - Wikipedia

    en.wikipedia.org/wiki/Sleep_and_Metabolism

    Sleep plays a vital role in regulating metabolism and appetite. When sleep deprived, the metabolic system will be out of balance, which will ultimately affect the dietary choices people make. Teens who are sleep deprived crave more carbohydrates. Sleep deprivation is a risk factor for obesity among young adults. [7] [medical citation needed]

  8. Bunker experiment - Wikipedia

    en.wikipedia.org/wiki/Bunker_experiment

    The bunker experiment was a scientific experiment that began in 1966 to test whether humans, like other species, have an intrinsic circadian clock. [1] It was started by Jürgen Aschoff and Rütger Wever of the Max Planck Institute for Behavioral Physiology and later taken over by Jürgen Zulley.

  9. Circadian rhythm - Wikipedia

    en.wikipedia.org/wiki/Circadian_rhythm

    A circadian rhythm (/ s ər ˈ k eɪ d i ə n /), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours.Circadian rhythms can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment (is entrained by the environment).