Atlas

An atlas is a collection of maps; it is typically a map of Earth or a region of Earth, but there are atlases of the other planets (and their satellites) in the Solar System. Furthermore, atlases of anatomy exist, mapping out the human body or other organisms. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geographic features and political boundaries, many atlases often feature geopolitical, social, religious and economic statistics. They also have information about the map and places in it.

Etymology

The word atlas dates from 1636, first in reference to the English translation of Atlas, sive cosmographicae meditationes de fabrica mundi (1585) by Flemish geographer Gerhardus Mercator, who might have been the first to use this word in this way. A picture of the Titan Atlas holding up the world appeared on the frontispiece of this and other early map collections.

History

The first work that contained systematically arranged woodcut maps of uniform size, intended to be published in a book, thus representing the first modern atlas, was De Summa totius Orbis (1524–26) by the 16th-century Italian cartographer Pietro Coppo. Nonetheless, this distinction is conventionally awarded to the Flemish cartographer Abraham Ortelius who in 1570 published the collection of maps Theatrum Orbis Terrarum.

Atlas (computer)

The Atlas Computer was a joint development between the University of Manchester, Ferranti, and Plessey. The first Atlas, installed at Manchester University and officially commissioned in 1962, was one of the world's first supercomputers, considered to be the most powerful computer in the world at that time. It was said that whenever Atlas went offline half of the United Kingdom's computer capacity was lost. It was a second-generation machine, using discrete germanium transistors. Two other Atlas machines were built: one for British Petroleum and the University of London, and one for the Atlas Computer Laboratory at Chilton near Oxford.

A derivative system was built by Ferranti for Cambridge University. Called the Titan, or Atlas 2, it had a different memory organisation and ran a time-sharing operating system developed by Cambridge University Computer Laboratory. Two further Atlas 2s were delivered: one to the CAD Centre in Cambridge (later called CADCentre, then AVEVA), and the other to the Atomic Weapons Research Establishment (AWRE), Aldermaston.

Atlas (topology)

In mathematics, particularly topology, one describes a manifold using an atlas. An atlas consists of individual charts that, roughly speaking, describe individual regions of the manifold. If the manifold is the surface of the Earth, then an atlas has its more common meaning. In general, the notion of atlas underlies the formal definition of a manifold and related structures such as vector bundles and other fibre bundles.

Charts

The definition of an atlas depends on the notion of a chart. A chart for a topological space M (also called a coordinate chart, coordinate patch, coordinate map, or local frame) is a homeomorphism from an open subset U of M to an open subset of Euclidean space. The chart is traditionally recorded as the ordered pair .

Formal definition of atlas

An atlas for a topological space M is a collection of charts on M such that . If the codomain of each chart is the n-dimensional Euclidean space and the atlas is connected, then M is said to be an n-dimensional manifold.

Doctor

Doctor or The Doctor may refer to:

Personal titles

Fictional characters

Film and television

Eighth Doctor

The Eighth Doctor is an incarnation of the Doctor, the protagonist of the BBC science fiction television series Doctor Who. He is portrayed by Paul McGann.

The character was introduced in the 1996 TV film Doctor Who, a back-door pilot produced in an unsuccessful attempt to relaunch the series following its 1989 cancellation. While the Eighth Doctor initially had only one on-screen appearance, his adventures were portrayed extensively in subsequent spin-off media, including more than 70 audio dramas starring McGann. In 2013, the actor reprised the role in the mini-episode "The Night of the Doctor", which depicts the Eighth Doctor's final adventure.

Within the series' narrative, the Doctor is a centuries-old alien, a Time Lord from the planet Gallifrey, who travels in time and space in his TARDIS, frequently with companions. When the Doctor is critically injured, he can regenerate his body but in doing so gains a new physical appearance and with it, a distinct new personality. McGann portrays the eighth such incarnation, a passionate, enthusiastic, and eccentric character. His only companion in the television film is Grace Holloway (Daphne Ashbrook), a medical doctor whose surgery is partly responsible for triggering his regeneration. In the continued adventures of the character depicted in audio dramas, novels and comic books he travels alongside numerous other companions, including self-styled "Edwardian Adventuress" Charley, the alien Destrii and present-day humans Lucie and Sam.

Playing doctor

"Playing doctor" is a phrase used colloquially in the western world to refer to children examining each other's genitals. It originates from children using the pretend roles of doctor and patient as a pretext for such an examination. However, whether or not such role-playing is involved, the phrase is used to refer to any similar examination.

Playing doctor is distinguished from child-on-child sexual abuse because the latter is an overt and deliberate action directed at sexual stimulation, including orgasm, as compared to anatomical curiosity. Playing doctor is considered by most child psychologists to be a normal step in childhood development between the ages of approximately three and six years, so long as all parties are willing participants and relatively close in age. However, it can be a source of discomfort to some parents to discover their children are engaging in such an activity. Parenting professionals often advise parents to view such a discovery as an opportunity to calmly teach their children about the differences between the sexes, personal privacy, and respecting the privacy of other children.