Wakefulness

Wakefulness is a daily recurring brain state and state of consciousness in which an individual is conscious and engages in coherent cognitive and behavioral responses to the external world such as communication, ambulation, eating, and sex. Being awake is the opposite of the state of being asleep in which most external inputs to the brain are excluded from neural processing.

Effects upon the brain

The longer the brain has been awake, the greater the spontaneous firing rates of cerebral cortex neurons with this increase being reversed by sleep. Another effect of wakefulness (which may or may not be related to this) is that it lowers the small stores of glycogen held in the astrocytes that can supply energy to the brain's neurons—one of the functions of sleep, it has been proposed, is to create the opportunity for them to be replenished.

Maintenance by the brain

Wakefulness is produced by a complex interaction between multiple neurotransmitter systems arising in the brainstem and ascending through the midbrain, hypothalamus, thalamus and basal forebrain. The posterior hypothalamus plays a key role in the maintenance of the cortical activation that underlies wakefulness. Several systems originating in this part of the brain control the shift from wakefulness into sleep and sleep into wakefulness. Histamine neurons in the tuberomammillary nucleus and nearby adjacent posterior hypothalamus project to the entire brain and are the most wake-selective system so far identified in the brain. Another key system is that provided by the orexins (also known as hypocretins) projecting neurons. These exist in areas adjacent to histamine neurons and like them project widely to most brain areas and associate with arousal. Orexin deficiency has been identified as responsible for narcolepsy.

Awake (Donkeyboy song)

Awake is an English language hit in Norway for the Norwegian band Donkeyboy, their fourth single taken from their album Caught in a Life after singles "Ambitions" and "Sometimes" (both #1s for 13 and 8 weeks consecutively in the Norwegian Singles Chart) and "Broke My Eyes" (that reached #6).

"Awake" released in 2009 reached #8 in the Norwegian Singles Chart.

Charts

References

Awake (EP)

Awake is the first EP release from American rock band Bleed the Dream on their own label "Noize Pollution" in 2003.

Track listing

Personnel

Tycho

Tycho may refer to:

People

Astronomy

Fiction

Software engineering

Tycho (musician)

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Tycho (pronounced like Tie-ko, with emphasis on the first syllable) is an American ambient music project led by Scott Hansen (born 1976 or 1977) as primary composer, songwriter and producer. Hailing from San Francisco, California, he is known as ISO50 for his photographic and design works. His music is a combination of downtempo vintage-style synthesizers and ambient melodies. The style of his music is very organic, typically incorporating clips of the human element into his songs (i.e. weather broadcasts, simple talking, or even breathing). His song, "Dictaphone's Lament", was used as the track on a music video entitled "Live Life to the Fullest", which was made by and featured on the action cartoon block Toonami. His song "Cascade" (originally made for an Adult Swim and Ghostly International compilation called Ghostly Swim) was played during the final moments of the original 11-year run of Toonami in 2008. As of December 2014, Tycho is signed to, and has released under, Ghostly International, but has also released music on Merck Records and Gammaphone Records.

Tycho-2 Catalogue

The Tycho-2 Catalogue is a catalogue of more than 2.5 million of the brightest stars.

Catalogue

The astrometric reference catalogue contain positions, proper motions, and two-color photometric data for the 2,539,913 of the brightest stars in the Milky Way, of which about 9000 are visible to the naked eye. Components of double stars with separations down to 0.8 arcseconds are included. The catalog is 99% complete to magnitudes of V~11.0 and 90% complete to V~11.5. (, Table 1)

The Tycho-2 positions and magnitudes are based on the observations collected by the star mapper of the European Space Agency's Hipparcos satellite. They are the same observations used to compile the Tycho-1 Catalogue (ESA SP-1200, 1997). However, Tycho-2 is much larger and a bit more precise, because a more advanced reduction technique was used.

The U.S. Naval Observatory (USNO) first compiled the ACT (Astrographic Catalog/Tycho) Reference Catalog, containing nearly one million stars, by combining the Astrographic Catalogue (AC 2000) with the Tycho-1 Catalogue; the large epoch span between the two catalogs improved the accuracy of proper motions by about an order of magnitude. Tycho-2 now supersedes the ACT.