The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subsequently the partitioning of its cytoplasm, chromosomes and other components into two daughter cells in a process called cell division. In cells with nuclei (eukaryotes, i.e., animal, plant, fungal, and protist cells), the cell cycle is divided into two main stages: interphase and the mitotic (M) phase (including mitosis and cytokinesis). During interphase, the cell grows, accumulating nutrients needed for mitosis, and replicates its DNA and some of its organelles. During the mitotic phase, the replicated chromosomes, organelles, and cytoplasm separate into two new daughter cells. To ensure the proper replication of cellular components and division, there are control mechanisms known as cell cycle checkpoints after each of the key steps of the cycle that determine if the cell can progress to the next phase....

Form follows function is a principle of design associated with late 19th and early 20th century architecture and industrial design in general, which states that the shape of a building or object should primarily relate to its intended function or purpose. Origins of the phrase The architect Louis Sullivan coined the maxim, which resumes Viollet-le-Duc's théories : a rationally designed structure may not necessarily be beautiful but no building can be beautiful that does not have a rationally designed structure. The maxim is often incorrectly attributed to the sculptor Horatio Greenough (1805–1852), whose thinking mostly predates the later functionalist approach to architecture. Greenough's writings were for a long time largely forgotten, and were rediscovered only in the 1930s. In 1947, a selection of his essays was published as Form and Function: Remarks on Art by Horatio Greenough.” Sullivan was Greenough's much younger compatriot and admired rationalist thinkers such as Thoreau, Emerson, Whitman, and Melville, as well as Greenough himself. In 1896, Sullivan coined the phrase in an article titled...

Cosmic dust – also called extraterrestrial dust, space dust, or star dust – is dust that occurs in outer space or has fallen onto Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 μm), such as micrometeoroids. Larger particles are called meteoroids. Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust (as in the zodiacal cloud), and circumplanetary dust (as in a planetary ring). There are several methods to obtain space dust measurement. In the Solar System, interplanetary dust causes the zodiacal light. Solar System dust includes comet dust, planetary dust (like from Mars), asteroidal dust, dust from the Kuiper belt, and interstellar dust passing through the Solar System. Thousands of tons of cosmic dust are estimated to reach Earth's surface every year, with most grains having a mass between 10−16 kg (0.1 pg) and 10−4 kg (0.1 g). The density of the dust cloud through which the Earth is traveling is approximately 10−6 dust grains/m3.Cosmic dust contains some complex organic compounds (amorphous...

Elimia tenera, formerly known as Goniobasis tenera, is an extinct species of freshwater snail with an operculum, in the aquatic gastropod mollusk family Pleuroceridae. This species flourished during the Eocene and is now known only from the fossil record. The genus name Elimia was restored to this species in 1975; formerly it was placed in Goniobasis. Green River Formation deposits Fossilized Elimia tenera shells occur in a region which is now southern Wyoming, northern Colorado and northeastern Utah. The best preserved Elimia tenera are from Lake Gosiute which fossils occur in the Fort Laclede Bed of the Laney Member at outcrops in Sweetwater County, in southwestern Wyoming. 'Turritella agate' The fossils are hosted in chalcedony-rich sedimentary rock. This rock was originally incorrectly called Turritella agate. It was named after the sea snail genus Turritella because of the...

Vector graphics is a form of computer graphics in which visual images are created directly from geometric shapes defined on a Cartesian plane, such as points, lines, curves and polygons. The associated mechanisms may include vector display and printing hardware, vector data models and file formats, as well as the software based on these data models (especially graphic design software, computer-aided design, and geographic information systems). Vector graphics is an alternative to raster or bitmap graphics, with each having advantages and disadvantages in specific situations.While vector hardware has largely disappeared in favor of raster-based monitors and printers, vector data and software continues to be widely used, especially when a high degree of geometric precision is required, and when complex information can be decomposed into simple geometric primitives. Thus, it is the preferred model for domains such as engineering, architecture, surveying, 3D rendering, and typography, but is entirely inappropriate for applications such as photography and remote sensing, where raster is more effective and efficient....

Rare Disease Day is an observance held on the last day of February to raise awareness for rare diseases and improve access to treatment and medical representation for individuals with rare diseases and their families. The European Organisation for Rare Diseases established the day in 2008 to raise awareness for unknown or overlooked illnesses. According to that organization, treatment for many rare diseases is insufficient, as are the social networks to support individuals with rare diseases and their families; furthermore, while there were already numerous days dedicated to individuals with specific diseases (such as AIDS, cancer, etc.), there had previously not been a day for representing those affected by rare diseases. In 2009, Rare Disease Day went global as the National Organization for Rare Disorders mobilized 200 rare disease patient advocacy organizations in the United States while organizations in China, Australia, Taiwan, and Latin America also lead efforts in their respective countries to coordinate activities and promote the day. History The first Rare Disease Day was coordinated by the European Organisation for Rare...

Feudalism, also known as the feudal system, was the combination of the legal, economic, military, cultural and political customs that flourished in medieval Europe between the 9th and 15th centuries. Broadly defined, it was a way of structuring society around relationships that were derived from the holding of land in exchange for service or labour. Although it is derived from the Latin word feodum or feudum (fief), which was used during the Medieval period, the term feudalism and the system which it describes were not conceived of as a formal political system by the people who lived during the Middle Ages. The classic definition, by François Louis Ganshof (1944), describes a set of reciprocal legal and military obligations which existed among the warrior nobility and revolved around the three key concepts of lords, vassals, and fiefs.A broader definition of feudalism, as described by Marc Bloch (1939), includes not only the obligations of the warrior nobility but the obligations of all three estates of the realm: the nobility, the clergy, and the peasantry, all of whom were bound by a system of manorialism...

Around 20 vegan demonstrators stormed a restaurant in the English seaside resort of Brighton on Saturday.

Tobacco use has predominantly negative effects on human health and concern about health effects of tobacco has a long history. Research has focused primarily on cigarette smoking.Tobacco smoke contains more than 70 chemicals that cause cancer. Tobacco also contains nicotine, which is a highly addictive psychoactive drug. When tobacco is smoked, nicotine causes physical and psychological dependency. Cigarettes sold in underdeveloped countries tend to have higher tar content, and are less likely to be filtered, potentially increasing vulnerability to tobacco smoking–related disease in these regions.Tobacco use is the single greatest cause of preventable death globally. As many as half of people who use tobacco die from complications of tobacco use. The World Health Organization (WHO) estimates that each year tobacco causes about 6 million deaths (about 10% of all deaths) with 600,000 of these occurring in non-smokers due to second-hand smoke. Tobacco is estimated to have caused 100 million deaths in the 20th century. Similarly, the United States Centers for Disease Control and Prevention describes tobacco use as "the single most...

Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluorescence, a phosphorescent material does not immediately reemit the radiation it absorbs. Instead, a phosphorescent material absorbs some of the radiation energy and reemits it for a much longer time after the radiation source is removed. In a general sense, there is no distinct boundary between the emission times of fluorescence and phosphorescence (i.e.: if a substance glows under a black light it is generally considered fluorescent, and if it glows in the dark it is often simply called phosphorescent). In a modern, scientific sense, the phenomena can usually be classified by the three different mechanisms that produce the light, and the typical timescales during which those mechanisms emit light. Whereas fluorescent materials stop emitting light within nanoseconds (billionths of a second) after the excitation radiation is removed, phosphorescent...