An afterimage or ghost image is an optical illusion that refers to an image continuing to appear in one's vision after the exposure to the original image has ceased. One of the most common afterimages is the bright glow that seems to float before one's eyes after staring at a light bulb or a headlight for a few seconds. The phenomenon of afterimages may be closely related to persistence of vision, which allows a rapid series of pictures to portray motion, which is the basis of animation and cinema. Afterimages come in two forms, negative (inverted) and positive (retaining original color). The process behind positive afterimages is unknown, though thought to be related to neural adaptation. On the other hand, negative afterimages are a retinal phenomenon and are well understood. Negative afterimages are caused when the eye's photoreceptors, primarily those known as cone cells, adapt from the over stimulation and lose sensitivity. Normally the eye deals with this problem by rapidly moving the eye small amounts (see: microsaccade), the motion later being "filtered out" so it is not noticeable.
Mittwoch, 3. Dezember 2008
Afterimage
Dienstag, 2. Dezember 2008
Syndicalism
Syndicalism is a type of movement which aims to degrade capitalist societies through action by the working class on the industrial front. For syndicalists, labor unions are the potential means both of overcoming capitalism and of running society in the interests of the majority. Industry and government in a syndicalist society would be run by labour union federations. This emphasis on industrial organization was a distinguishing feature of syndicalism when it began to be identified as a distinct current at the beginning of the 20th century. Most socialist organisations of that period emphasised the importance of political action through party organizations as a means of bringing about socialism. Although all syndicalists emphasize industrial organization, not all reject political action altogether. For example, De Leonists and some other Industrial Unionists advocate parallel organisation both politically and industrially. Syndicalisme is a French word meaning "trade unionism". This milder version of syndicalism was overshadowed by revolutionary anarcho-syndicalism in the early 20th century.
MCPA
MCPA or 2-methyl-4-chlorophenoxyacetic acid is a powerful, selective, widely-used phenoxy herbicide. The pure compound is a brown-colored powder. Synthesis of MCPA was first reported by Synerholme and Zimmerman in 1945 and by Templeman and Foster in 1946. Templeman and Foster were searching for a compounds with similar or greater selective activity than 1-naphthaleneacetic acid in inhibiting the growth of weeds while not adversely affecting the growth of cereal grains. They synthesized MCPA from the corresponding phenol by exposing it to chloroacetic acid and dilute base in a straightforward substitution reaction: Because it is inexpensive, MCPA is used in various chemical applications. Its carboxylic acid group allows the formation of conjugated complexes with metals (see below). The acid functionality makes MCPA a versatile synthetic intermediate for more complex derivatives. MCPA is used as an herbicide, generally as its salt or esterified forms.
Pkunk
The Pkunk are a fictional race of beings featured in the Star Control computer game series, introduced in the second game. The Pkunk are a race of toucan or dodo like bird creatures that are an offshoot of the Yehat. They ally with the protagonist in Star Control II as soon as he meets them. Psychologically the Pkunk resemble a stereotypical phony psychic, constantly agreeing with anything mystical the player says and basing all their decisions on universal harmony and similar grand sounding concepts. However, the Pkunk really are powerful psychics who are able to provide various hints to the player, even going so far as actual clairvoyance. Perhaps the Pkunk's greatest achievement was to convince the Yehat to turn away from their violent honour based culture, in the Yehat's own words "we only thought we were being happy birds of prey" The Pkunk believe that their psychotic neighbours, the Ilwrath, were initially wonderful and peaceful beings who became a tiny smidgen too good and wrapped all the way around to evil. To avoid such a fate, the Pkunk, as well as being harmonious and pacifistic, always make sure to be slightly annoying to all they meet.
Montag, 1. Dezember 2008
Cretaceous
The Cretaceous (pronounced /kriːˈteɪʃəs/, usually abbreviated 'K' for its German translation "Kreide") is a geologic period and system, reaching from the end of the Jurassic Period, (145.5 ± 4 million years ago (Ma) to the beginning of the Paleocene Period, 65.5 ± 0.3 Ma. It is the youngest geological period of the Mesozoic, and at 80 million years long, the longest period of the Phanerozoic. The end of the Cretaceous defines the boundary between the Mesozoic and Cenozoic eras. The Cretaceous (from Latin creta meaning 'chalk' ) as a separate period was first defined by a Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris Basin and named for the extensive beds of chalk (calcium carbonate deposited by the shells of marine invertebrates, principally coccoliths), found in the upper Cretaceous of continental Europe and the British Isles (including the White Cliffs of Dover). As with other older geologic periods, the rock beds that define the Cretaceous are well identified but the exact dates of the period's start and end are uncertain by a few million years. No great extinction or burst of diversity separated the Cretaceous from the Jurassic.
Swastika
The swastika (from Sanskrit: svástika स्वस्तिक ) is an equilateral cross with its arms bent at right angles, in either right-facing (卐) form or its mirrored left-facing (卍) form. The swastika can also be drawn as a traditional swastika, but with a second 90° bend in each arm. Archaeological evidence of swastika-shaped ornaments dates from the Neolithic period. An ancient symbol, it occurs mainly in the cultures that are in modern day India and the surrounding area, sometimes as a geometrical motif (as in the Roman Republic and Empire) and sometimes as a religious symbol. It was long widely used in major world religions such as Hinduism, Buddhism and Jainism. Though once commonly used all over much of the world without stigma, because of its iconic usage in Nazi Germany, the symbol has become controversial in the Western world. The word swastika is derived from the Sanskrit word svastik (in Devanagari, स्वस्तिक), meaning any lucky or auspicious object, and in particular a mark made on persons and things to denote good luck.
Ewhurst
Ewhurst is a small village in the English county of Surrey. Ewhurst is located between Cranleigh (two miles away) and Shere which is around five miles in the other direction. Ewhurst has many well-known legends as members of the village, such as Eric Clapton, who is known to play at the Church of England church in Ewhurst. It also houses other stars as Kenney Jones of the Who and Jim Davidson. No knowledge exists of when cricket was first played on Ewhurst Green, but an article in an old Surrey magazine of 1947 said that cricket had been played on The Green for at least 100 years. This must mean that it is at least 165 years old. Also the cricket historian, Tom Bing, who lived locally said that he had found evidence that cricket had been played between the villages of Ewhurst and Rudgwick as far back as the late 18th century. Local families such as the Wellers, Warringtons, Barlows and Osgoods have served the club with distinction throughout the years. A minute book held at the Guildford Library relates how cricket was played in the village from the turn of the 20th century up to World War I.