- published: 14 Jul 2013
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A lullaby or cradle-song, also spelled cradle song, is a soothing song or piece of music, usually played or sung to children or adults. The purposes of lullabies vary. In some societies they are used to pass down cultural knowledge or tradition. In addition, lullabies are often used for the developing of communication skills, indication of emotional intent, maintenance of infants' undivided attention, modulation of infants' arousal, and regulation of behavior. Perhaps one of the most important uses of lullabies is as a sleep aid for infants. As a result, the music is often simple and repetitive. Lullabies can be found in many countries, and have existed since ancient times.
Lullabies tend to share exaggerated melodic tendencies, including simple pitch contours, large pitch ranges, and generally higher pitch. These clarify and convey heightened emotions, usually of love or affection. When there is harmony, infants almost always prefer consonant intervals over dissonant intervals. Furthermore, if there is a sequence of dissonant intervals in a song, an infant will usually lose interest and it becomes very difficult to regain its attention. To reflect this, most lullabies contain primarily consonant intervals. Tonally, most lullabies are simple, often merely alternating tonic and dominant harmonies.
A city is a large and permanent human settlement. Although there is no agreement on how a city is distinguished from a town in general English language meanings, many cities have a particular administrative, legal, or historical status based on local law.
Cities generally have complex systems for sanitation, utilities, land usage, housing, and transportation. The concentration of development greatly facilitates interaction between people and businesses, benefiting both parties in the process, but it also presents challenges to managing urban growth.
A big city or metropolis usually has associated suburbs and exurbs. Such cities are usually associated with metropolitan areas and urban areas, creating numerous business commuters traveling to urban centers for employment. Once a city expands far enough to reach another city, this region can be deemed a conurbation or megalopolis. In terms of population, the largest city proper is Shanghai, while the fastest-growing is Dubai.
There is not enough evidence to assert what conditions gave rise to the first cities. Some theorists have speculated on what they consider suitable pre-conditions and basic mechanisms that might have been important driving forces.