2,4-Dichlorophenoxyacetic acid

2,4-Dichlorophenoxyacetic acid (usually called 2,4-D) is an organic compound with the chemical formula C₈H₆Cl₂O₃. It is a systemic herbicide which selectively kills most broadleaf weeds by causing uncontrolled growth in them, but leaves most grasses such as cereals, lawn turf, and grassland relatively unaffected.

2,4-D is one of oldest and most widely available herbicides in the world, having been commercially available since 1945, and is now produced by many chemical companies since the patent on it has long since expired. It can be found in numerous commercial lawn herbicide mixtures, and is widely used as a weedkiller on cereal crops, pastures, and orchards. Over 1,500 herbicide products contain 2,4-D as an active ingredient.

Controversies

2,4-D is a possible carcinogen per WHO. The International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization said 2,4-D was classified as "possibly carcinogenic to humans (Group 2B), based on inadequate evidence in humans and limited evidence in experimental animals". This puts 2,4-D in the same risk category as coffee and red meat but rates it as less likely to be carcinogenic than processed meat, which was placed in Group 1.

4D

4D or 4-D may refer to:

In entertainment:

Rubik's Cube

Rubik's Cube is a 3-D combination puzzle invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik. Originally called the Magic Cube, the puzzle was licensed by Rubik to be sold by Ideal Toy Corp. in 1980 via businessman Tibor Laczi and Seven Towns founder Tom Kremer, and won the German Game of the Year special award for Best Puzzle that year. As of January 2009, 350 million cubes had been sold worldwide making it the world's top-selling puzzle game. It is widely considered to be the world's best-selling toy.

In a classic Rubik's Cube, each of the six faces is covered by nine stickers, each of one of six solid colours: white, red, blue, orange, green, and yellow. In currently sold models, white is opposite yellow, blue is opposite green, and orange is opposite red, and the red, white and blue are arranged in that order in a clockwise arrangement. On early cubes, the position of the colours varied from cube to cube. An internal pivot mechanism enables each face to turn independently, thus mixing up the colours. For the puzzle to be solved, each face must be returned to have only one colour. Similar puzzles have now been produced with various numbers of sides, dimensions, and stickers, not all of them by Rubik.

Self-assembly

Self-assembly is a process in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves, without external direction. When the constitutive components are molecules, the process is termed molecular self-assembly.

Self-assembly can be classified as either static or dynamic. In static self-assembly, the ordered state forms as a system approaches equilibrium, reducing its free energy. However, in dynamic self-assembly, patterns of pre-existing components organized by specific local interactions are not commonly described as "self-assembled" by scientists in the associated disciplines. These structures are better described as "self-organized".

Self-assembly in chemistry and materials science

Self-assembly (SA) in the classic sense can be defined as the spontaneous and reversible organization of molecular units into ordered structures by non-covalent interactions. The first property of a self-assembled system that this definition suggests is the spontaneity of the self-assembly process: the interactions responsible for the formation of the self-assembled system act on a strictly local level—in other words, the nanostructure builds itself.

Got Talent

Got Talent is a talent show television format conceived and owned by Simon Cowell's SYCOtv company. A pilot was made in the United Kingdom in 2005, hosted by Paul O'Grady, but after O'Grady's split with ITV, the series was postponed, resulting in America's Got Talent – the first full series of the format.

It has spawned spin-offs in over 58 countries (as of April 2014), in what is now referred to as the Got Talent format, similar to that described by FremantleMedia of the Idol and The X Factor formats. In April 2014, the format was named the world's most successful reality TV format ever by the Guinness World Records.

History

Got Talent was an invention by The X Factor creator Simon Cowell, with comedian and talk show host Paul O'Grady producing a pilot for ITV in 2005 under the provisional title Paul O'Grady's Got Talent. O'Grady left the network after disputes with ITV, resulting in Cowell moving the concept to the United States while he and ITV searched for a new show host.

Due to these issues, the Got Talent franchise ended up debuting first as America's Got Talent on NBC on 21 June 2006, with judges David Hasselhoff, Brandy Norwood, and Piers Morgan. The show's original series was hosted by Regis Philbin. In 2016, the judging panel consisted of Howie Mandel, Heidi Klum, Melanie Brown, and Simon Cowell, and hosted by Nick Cannon, who has been the presenter since 2009. The grand prize on America's Got Talent is $1 million, and, since season 3, a chance to headline a show on the Las Vegas Strip. America's Got Talent proved extremely successful for NBC, pulling in high ratings in both total viewers and the younger 18-49 demographic. The show's initial success in America is credited with the eventual launch of the British series, and the overall global launch of the Got Talent franchise.