The Control Document Index includes BLM documents that affect or have affected the control, limitation, or restriction of public land and resources. CDI documents include public laws, proclamations, and withdrawals. CDI documents have been kept on microfilm since the 1950’s, but are now being scanned and linked to existing data records from BLM’s LR2000 database.

The Ku Klux Klan, was founded in 1865 in Pulaski, Tennessee as a vigilante organization whose goal was to keep control over freed slaves; It performed acts of lawlessness against negroes and other minorities. This included taking negro prisoners from the custody of officers or breaking into jails to put them to death. Few efforts were made by civil authorities in the South against the Ku …

Turing Award, in full A.M. Turing Award, annual award given by the Association for Computing Machinery (ACM), a professional computing society founded in 1947, to one or more individuals “selected for contributions of a technical nature made to the computing community.” The Turing Award is often referred to as the computer science equivalent of the Nobel Prize. The Turing …

space group, in crystallography, any of the ways in which the orientation of a crystal can be changed without seeming to change the position of its atoms. These changes may involve displacement of the whole structure along a crystallographic axis (translation), as well as the point group operations of rotation about an axis, reflection in a plane, inversion about a centre, or …

isomorphism, in modern algebra, a one-to-one correspondence (mapping) between two sets that preserves binary relationships between elements of the sets. For example, the set of natural numbers can be mapped onto the set of even natural numbers by multiplying each natural number by 2. The binary operation of adding two numbers is preserved—that is, adding two natural …

Pong, groundbreaking electronic game released in 1972 by the American game manufacturer Atari, Inc. One of the earliest video games, Pong became wildly popular and helped launch the video game industry. The original Pong consisted of two paddles that players used to volley a small ball back and forth across a screen. The German-born American television engineer …

Un jeu vidéo de réflexion, jeu de puzzle ou puzzle game, est un genre de jeu vidéo centré sur la réflexion.Ce genre de jeux amène le joueur à résoudre des casse-têtes (tels que ceux de Sokoban), des énigmes, ou à naviguer à travers des lieux complexes comme des labyrinthes.Il fait appel chez les joueurs à des aptitudes comme la logique, la reconnaissance de formes ou …

elliptic equation, any of a class of partial differential equations describing phenomena that do not change from moment to moment, as when a flow of heat or fluid takes place within a medium with no accumulations. The Laplace equation, uxx + uyy = 0, is the simplest such equation describing this condition in two dimensions. In addition to satisfying a differential equation within the …

ornithopter, machine designed to fly by the flapping of its wings in imitation of birds. The wooden bird said to have been made about 400 bc by Archytas of Tarentum is one of the earliest examples. The Greek myth of Daedalus and Icarus involves man’s use of wings in the manner of birds. Leonardo da Vinci made many drawings and models of such aircraft in the late 15th …

Web 2.0, term devised to differentiate the post-dotcom bubble World Wide Web with its emphasis on social networking, content generated by users, and cloud computing from that which came before. The 2.0 appellation is used in analogy with common computer software naming conventions to indicate a new, improved version. The term had its origin in the name given to a …