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Light seems to have therapeutic antidepressant effects when an organism is exposed to it at appropriate times during the circadian rhythm, regulating the sleep-wake cycle. [6] [4] In addition to mood, learning and memory become impaired when the circadian system shifts due to light stimuli, [6] [20] which can be seen in studies modeling jet lag ...
Tyrian purple is a pigment made from the mucus of several species of Murex snail. Production of Tyrian purple for use as a fabric dye began as early as 1200 BC by the Phoenicians, and was continued by the Greeks and Romans until 1453 AD, with the fall of Constantinople.
Chromostereopsis is a visual illusion whereby the impression of depth is conveyed in two-dimensional color images, usually of red–blue or red–green colors, but can also be perceived with red–grey or blue–grey images. [1] [2] Such illusions have been reported for over a century and have generally been attributed to some form of chromatic ...
Shades of purple. There are numerous variations of the color purple, a sampling of which is shown below. In common English usage, purple is a range of hues of color occurring between red and blue. [1] However, the meaning of the term purple is not well defined. There is confusion about the meaning of the terms purple and violet even among ...
Deep reddish purple. B: Normalized to [0–255] (byte) The color Byzantium is a particular dark tone of purple. It originates in modern times, and, despite its name, it should not be confused with Tyrian purple ( hue rendering ), the color historically used by Roman and Byzantine emperors. The latter, often also referred to as "Tyrian red", is ...
Non-24-hour sleep–wake disorder causes a person's sleep–wake cycle to move around the clock every day, to a degree dependent on the length of the cycle. This is known as free-running sleep. [citation needed] People with the disorder may have an especially hard time adjusting to changes in "regular" sleep–wake cycles, such as vacations ...
Blue light, a type of high-energy light, is part of the visible light spectrum. High-energy visible light (HEV light) is short-wave light in the violet/blue band from 400 to 450 nm in the visible spectrum, which has a number of purported negative biological effects, namely on circadian rhythm and retinal health (blue-light hazard), which can lead to age-related macular degeneration.
In optics, violet is a spectral color (referring to the color of different single wavelengths of light), whereas purple is the color of various combinations of red and blue (or violet) light, some of which humans perceive as similar to violet. In common usage, both terms are used to refer to a variety of colors between blue and red in hue.