Key (lock)

A key is a device that is used to operate a lock (such as to lock or unlock it). A typical key is a small piece of metal consisting of two parts: the blade, which slides into the keyway of the lock and distinguishes between different keys, and the bow, which is left protruding so that torque can be applied by the user. A key is usually intended to operate one specific lock or a small number of locks that are keyed alike, so each lock requires a unique key. The key serves as a security token for access to the locked area; only persons having the correct key can open the lock and gain access.

Keys provide an inexpensive, though imperfect, method of access control for access to physical properties like buildings, vehicles and cupboards or cabinets. As such, keys are an essential feature of modern living, and are common around the world. It is common for people to carry the set of keys they need for their daily activities around with them, often linked by a keyring adorned by trinkets usually known as a keychain.

Armlock

An armlock in grappling is a single or double joint lock that hyperextends, hyperflexes or hyperrotates the elbow joint and/or shoulder joint. An armlock that hyperflexes or hyperrotates the shoulder joint is referred to as a shoulder lock, and an armlock that hyperextends the elbow joint is called an armbar. Depending on the joint flexibility of a person, armlocks that hyperrotate the shoulder joint can also hyperrotate the elbow joint, and vice versa.

Obtaining an armlock requires effective use of full-body leverage in order to initiate and secure a lock on the targeted arm, while preventing the opponent from escaping the lock. Therefore, performing an armlock is less problematic on the ground, from positions such as the mount, side control, or guard. Armlocks are more difficult to perform when both combatants are standing up, though the stand-up variants are a focus in certain systems such as Chin Na. Furthermore, a failed armlock can sometimes result in the opponent escaping and obtaining a dominant position.

Keynote (presentation software)

Keynote is a presentation software application developed as a part of the iWork productivity suite by Apple Inc. Keynote 6.0 was announced on October 23, 2013 and is the most recent version for the Mac. On January 27, 2010, Apple announced a new version of Keynote for iPad with an all new touch interface.

History

Keynote began as a computer program for Apple CEO Steve Jobs to use in creating the presentations for Macworld Conference and Expo and other Apple keynote events. Prior to using Keynote, Jobs had used Concurrence, from Lighthouse Design, a similar product which ran on the NeXTSTEP and OpenStep platforms.

The program was first sold publicly as Keynote 1.0 in 2003, competing against existing presentation software, most notably Microsoft PowerPoint.

In 2005 Apple began selling Keynote 2.0 in conjunction with Pages, a new word processing and page layout application, in a software package called iWork. At the Macworld Conference & Expo 2006, Apple released iWork '06 with updated versions of Keynote 3.0 and Pages 2.0. In addition to official HD compatibility, Keynote 3 added new features, including group scaling, 3D charts, multi-column text boxes, auto bullets in any text field, image adjustments, and free form masking tools. In addition, Keynote features three-dimensional transitions, such as a rotating cube or a simple flip of the slide.

Database index

A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes and storage space to maintain the index data structure. Indexes are used to quickly locate data without having to search every row in a database table every time a database table is accessed. Indexes can be created using one or more columns of a database table, providing the basis for both rapid random lookups and efficient access of ordered records.

An index is a copy of select columns of data from a table that can be searched very efficiently that also includes a low-level disk block address or direct link to the complete row of data it was copied from. Some databases extend the power of indexing by letting developers create indices on functions or expressions. For example, an index could be created on upper(last_name), which would only store the upper case versions of the last_name field in the index. Another option sometimes supported is the use of partial indices, where index entries are created only for those records that satisfy some conditional expression. A further aspect of flexibility is to permit indexing on user-defined functions, as well as expressions formed from an assortment of built-in functions.

Key (music)

In music theory, the key of a piece is the tonic note and chord that provides a subjective sense of arrival and rest. Other notes and chords in the piece create varying degrees of tension, resolved when the tonic note or chord returns. The key may be major or minor, although major is assumed in a phrase like "this piece is in C." Popular songs are usually in a key, and so is classical music during the common practice period, about 1650–1900. Longer pieces in the classical repertoire may have sections in contrasting keys.

Methods that establish the key for a particular piece can be complicated to explain, and vary over music history. However, the chords most often used in a piece in a particular key are those that contain the notes in the corresponding scale, and conventional progressions of these chords, particularly cadences, orient the listener around the tonic.

The key signature is not a reliable guide to the key of a written piece. It does not discriminate between a major key and its relative minor; the piece may modulate to a different key; if the modulation is brief, it may not involve a change of key signature, being indicated instead with accidentals. Occasionally, a piece in a mode such as Mixolydian or Dorian is written with a major or minor key signature appropriate to the tonic, and accidentals throughout the piece.