Design characteristics.

A helicopter, sometimes referred to in slang as a "chopper", is a type of rotorcraft in which lift and thrust are supplied by one or more horizontally-spinning rotors. By contrast the autogyro (or gyroplane) and gyrodyne have a free-spinning rotor for all or part of the flight envelope, relying on a separate thrust system to propel the craft forwards, so that the airflow sets the rotor spinning to provide lift. The compound helicopter also has a separate thrust system, but continues to supply power to the rotor throughout normal flight.

Rotor system.

The rotor system, or more simply "rotor", is the rotating part of a helicopter that generates lift. A rotor system may be mounted horizontally, as main rotors are, providing lift vertically, or it may be mounted vertically, such as a tail rotor, to provide horizontal thrust to counteract torque from the main rotors.

Anti-torque.

Most helicopters have a single main rotor, but torque created by its aerodynamic drag must be countered by an opposed torque. The design that Igor Sikorsky settled on for his VS-300 was a smaller tail rotor. The tail rotor pushes or pulls against the tail to counter the torque effect, and this has become the most common configuration for helicopter design, usually at the end of a "tail boom". Some helicopters use other anti-torque controls instead of the tail rotor,

Engines.

The number, size and type of engine(s) used on a helicopter determines the size, function and capability of that helicopter design. The earliest helicopter engines were simple mechanical devices, such as rubber bands or spindles, which relegated the size of helicopters to toys and small models. For a half century before the first airplane flight, steam engines were used to forward the development of the understanding of helicopter aerodynamics, but the limited power did not allow for manned flight. The introduction of the internal combustion engine at the end of the 19th century became the watershed for helicopter development as engines began to be developed and produced that were powerful enough to allow for helicopters able to lift humans.  Early helicopter designs utilized custom-built engines or rotary engines designed for airplanes, but these were soon replaced by more powerful automobile engines and radial engines. The single, most-limiting factor of helicopter development during the first half of the 20th century was that the amount of power produced by an engine was not able to

Flight controls.

A helicopter has four flight control inputs. These are the cyclic, the collective, the anti-torque pedals, and the throttle. The cyclic control is usually located between the pilot's legs and is commonly called the "cyclic stick" or just "cyclic". On most helicopters, the cyclic is similar to a joystick. However, the Robinson R22 and Robinson R44 have a unique teetering bar cyclic control system and a few helicopters have a cyclic control that descends into the cockpit from overhead.  The control is called the cyclic because it changes cyclic pitch of the main blades. The result is to tilt the rotor disk in a particular direction, resulting in the helicopter moving in that direction. If the pilot pushes the cyclic forward, the rotor disk tilts forward, and the rotor produces a thrust in the forward direction. If the pilot pushes the cyclic to the side, the rotor disk tilts to that side and produces thrust in that direction, causing the helicopter to hover sideways.  The collective pitch control or "collective" is located on the left side of the pilot's seat with a settable friction control to prevent inadvertent movement. The collective changes the pitch

Compound helicopter.

A compound helicopter has an additional system for thrust and, typically, small stub fixed wings. This offloads the rotor in cruise, which

Flight.

There are three basic flight conditions for a helicopter: hover, forward flight and the transition between the two.

Hover.

Hovering is the most challenging part of flying a helicopter. This is because a helicopter generates its own gusty air while in a hover, which acts against the fuselage and flight control surfaces. The end result is constant control inputs and corrections by the pilot to keep the helicopter where it is required to be. Despite

Transition from hover to forward flight.

As a helicopter moves from hover to forward flight it enters a state called translational lift which provides

Forward flight.

In forward flight a helicopter's flight controls behave more like those of a fixed-wing aircraft. Displacing the cyclic forward will cause the nose to pitch down, with a resultant increase in airspeed and loss of altitude. Aft cyclic will cause the nose to pitch up, slowing the helicopter and causing it to climb. Increasing collective

Uses.

Due to the operating characteristics of the helicopter—its ability to take off and land vertically, and to hover for extended periods of time, as well as the aircraft's handling properties under low airspeed conditions—it has been chosen to conduct tasks that were previously not possible with other aircraft, or were time- or work-intensive to accomplish on the ground. Today, helicopter uses include transportation of people and cargo, military uses, construction, firefighting, search and rescue, tourism, medical transport, law enforcement, agriculture, news and media, and aerial observation, among others. They can be used for Reflection seismology or recreation.  A helicopter used to carry loads connected to long cables or slings is called an aerial crane. Aerial cranes are used to place heavy equipment, like radio transmission towers and large air conditioning units, on the tops of tall buildings, or when an item must be raised up in a remote area, such as a radio tower raised on the top of a hill or mountain. Helicopters are used as aerial cranes in the logging industry to lift trees out of terrain where vehicles cannot travel and where environmental concerns prohibit the building of roads. These operations are referred to as longline because of the long, single sling line used to carry the load.  The largest single non-combat helicopter operation in history was the disaster management operation following the 1986 Chernobyl nuclear disaster. Hundreds of pilots were involved in airdrop and observation missions, making dozens of sorties a day for several months.  "Helitack" is the use of helicopters to combat wildland fires. The helicopters are used for aerial firefighting (water bombing) and may be fitted with tanks or carry helibuckets. Helibuckets, such as the Bambi bucket, are usually filled by submerging the bucket into lakes, rivers, reservoirs, or portable tanks. Tanks fitted onto helicopters are filled from a hose while the helicopter is on the ground or water is siphoned from lakes or reservoirs through a hanging snorkel as the helicopter hovers over the water source. Helitack helicopters are also used to deliver firefighters, who rappel down to inaccessible areas, and to resupply firefighters. Common firefighting helicopters include variants of the Bell 205 and the Erickson S-64 Aircrane helitanker.  Helicopters are used as air ambulances for emergency medical assistance in situations when an ambulance cannot easily or quickly reach the scene, or cannot transport the patient to a medical facility in time. Helicopters are also used when patients need to be transported between medical facilities and air transportation is the most practical method. An air ambulance helicopter is equipped to stabilize and provide limited medical treatment to a patient while in flight. The use of helicopters as air ambulances is often referred to as "MEDEVAC", and patients are referred to as being "airlifted", or "medevaced". This use was pioneered in the Korean War, when time to reach a medical facility was reduced to three hours from the eight hours needed in World War II, and further reduced to two hours by the Vietnam War.  Police departments and other law enforcement agencies use helicopters to pursue suspects. Since helicopters can achieve a unique aerial view, they are often used in conjunction with police on the ground to report on suspects' locations and movements. They are often mounted with lighting and heat-sensing equipment for night pursuits.  Military forces use attack helicopters to conduct aerial attacks on ground targets. Such helicopters are mounted with missile launchers and miniguns. Transport helicopters are used to ferry troops and supplies where the lack of an airstrip would make transport via fixed-wing aircraft impossible. The use of transport helicopters to deliver troops as an attack force on an objective is referred to as "air assault". Unmanned aerial systems (UAS) helicopter systems of varying sizes are developed by companies for military reconnaissance and surveillance duties. Naval forces also use helicopters equipped with dipping sonar for anti-submarine warfare, since they can operate from small ships.  Oil companies charter helicopters to move workers and parts quickly to remote drilling sites located at sea or in remote locations. The speed advantage over boats makes the high operating cost of helicopters cost-effective in ensuring that oil platforms continue to operate. Various companies specialize in this type of operation.  NASA is developing the Mars Helicopter, a helicopter to be launched to survey Mars (along with a rover) in 2020. Given that the Martian atmosphere is 100 times thinner than that of Earth's, its two blades will spin at close to 3,000 revolutions a minute, approximately 10 times faster than that of a terrestrial helicopter.

History.

Early design.

The earliest references for vertical flight came from China. Since around 400 BC, Chinese children have played with bamboo flying toys (or Chinese top). This bamboo-copter is spun by rolling a stick attached to a rotor. The spinning creates lift, and the toy flies when released. The 4th-century AD Daoist book "Baopuzi" by Ge Hong (抱朴子 "Master who Embraces Simplicity") reportedly describes some of the ideas inherent to rotary wing aircraft.  Designs similar to the Chinese helicopter toy appeared in some Renaissance paintings and other works. In the 18th and early 19th centuries Western scientists developed flying machines based on the Chinese toy.  It was not until the early

First flights.

In 1906, two French brothers, Jacques and Louis Breguet, began experimenting with airfoils for helicopters. In 1907, those experiments resulted in the "Gyroplane No.1", possibly as the earliest known example of a quadcopter. Although there is some uncertainty about the date, sometime between 14 August and 29 September 1907, the Gyroplane No. 1 lifted its pilot into the air about for a minute. The Gyroplane No.1 proved to be extremely unsteady and required a man at each corner of the airframe to hold it steady. For this reason, the flights of the Gyroplane No.1 are considered to be the first manned flight of a helicopter, but not a free or untethered flight. That same year, fellow French inventor

Early development.

In the early 1920s, Argentine Raúl Pateras-Pescara de Castelluccio, while working in Europe, demonstrated one of the first successful applications of cyclic pitch. Coaxial, contra-rotating, biplane rotors could be warped to cyclically increase and decrease the lift they produced. The rotor hub could also be tilted forward a few degrees, allowing the aircraft to move forward without a separate propeller to push or pull it. Pateras-Pescara was also able to demonstrate the principle of autorotation. By January 1924, Pescara's helicopter No.1 was tested but was found to be underpowered and could not lift its own weight. His 2F fared better and set a record. The British government funded further research by Pescara which resulted in helicopter No. 3, powered by a radial engine which could fly for up to ten minutes.  On 14 April 1924, Frenchman Étienne Oehmichen set the first helicopter world record recognized by the "Fédération Aéronautique Internationale" (FAI), flying his quadrotor helicopter. On 18April 1924, Pescara beat Oemichen's record, flying for a distance of (nearly ) in 4 minutes and 11 seconds (about ), maintaining a height of. On 4May, Oehmichen completed the first closed-circuit helicopter flight in 7 minutes 40 seconds with his No. 2 machine.

Birth of an industry.

Heinrich Focke at Focke-Wulf was licensed to produce the Cierva C.30 autogyro in 1933. Focke designed the world's first practical transverse twin-rotor helicopter, the Focke-Wulf Fw 61, which first flew on 26 June 1936. The Fw 61 broke all of the helicopter world records in 1937, demonstrating a flight envelope that had only previously been achieved by the autogyro.  During World War II, Nazi Germany used helicopters in small numbers for observation, transport, and medical evacuation. The Flettner Fl 282 "Kolibri" synchropter—using the same basic configuration as Anton Flettner's own pioneering Fl 265—was used in the Mediterranean, while the Focke Achgelis Fa 223 "Drache" twin-rotor helicopter was used in Europe. Extensive bombing by the Allied forces prevented Germany from producing any helicopters in large quantities during the war.  In the United States, Russian-born engineer Igor Sikorsky and Wynn Laurence LePage competed to produce the U.S. military's first helicopter. LePage received the patent rights to develop helicopters patterned after the Fw

Turbine age.

In 1951, at the urging of his contacts at the Department of the Navy, Charles Kaman modified his K-225 synchropter — a design for a twin-rotor helicopter concept first pioneered by Anton Flettner in 1939, with the aforementioned Fl 265 piston-engined design in Germany – with a new kind of engine, the turboshaft engine. This adaptation of the turbine engine provided a large amount of power to Kaman's helicopter with a lower weight penalty than piston engines, with their heavy engine blocks and auxiliary components. On 11December 1951, the Kaman K-225 became

Safety.

Maximum speed limit.

There are several reasons a helicopter cannot fly as fast as a fixed-wing aircraft. When the helicopter is hovering, the outer tips of the rotor travel at a speed determined by the length of the blade and the rotational speed. In a moving helicopter, however, the speed of the blades relative to the air depends on the speed of the helicopter as well as on their rotational speed. The airspeed of the advancing rotor blade is much higher than that of the helicopter itself. It is possible for this blade to exceed the speed of sound, and thus produce vastly increased drag and vibration.  At the same time, the advancing blade creates more lift traveling forward, the retreating blade produces less lift. If the aircraft were to accelerate to the air speed that the blade tips are

Noise.

During the closing years of the 20th century designers began working on helicopter noise reduction. Urban communities have often expressed great dislike of noisy aviation or

Vibration.

Helicopters also vibrate; an unadjusted helicopter can easily vibrate so much that it will shake itself apart. To reduce vibration, all helicopters have rotor adjustments for height and weight. Blade height is adjusted by changing the pitch of the blade. Weight is adjusted by adding or removing weights on the rotor head and/or at the blade end caps. Most also have vibration dampers for height and pitch. Some also use mechanical feedback systems to sense and counter vibration. Usually the feedback system uses a mass as

Loss of tail-rotor effectiveness.

For a standard helicopter with a single main rotor, the tips of the main rotor blades produce a vortex ring in the air, which is a spiraling and circularly rotating airflow. As the craft moves forward, these vortices trail off behind the craft.  When hovering with a forward diagonal crosswind, or moving in a forward diagonal direction, the spinning vortices trailing off the main rotor blades will align with the rotation of the tail rotor and cause an instability in flight control.

Critical wind azimuth.

For a standard helicopter with a single main rotor, maintaining steady flight with a crosswind presents an additional flight control problem, where strong crosswinds from certain angles will increase or decrease lift from the main rotors. This effect is

Transmission.

Conventional rotary-wing aircraft use a set of complex mechanical gearboxes to convert the high rotation speed of gas turbines into the low speed required to drive main and tail rotors. Unlike powerplants, mechanical gearboxes cannot be duplicated (for redundancy) and have always been a major weak point in helicopter reliability. In-flight catastrophic gear failures often result in gearbox jamming and subsequent fatalities, whereas loss of lubrication can trigger onboard fire. Another weakness of mechanical gearboxes is their transient power limitation, due to structural fatigue limits. Recent EASA studies

Hazards.

As with any moving vehicle, unsafe operation could result in loss of

A helicopter, sometimes referred to in slang as a "chopper" or "helo" (United States military usage, pronounced with a long "e"), is a type of rotorcraft in which lift and thrust are supplied by horizontally-spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward, and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of VTOL (Vertical TakeOff and Landing) aircraft cannot perform.

Un hélicoptère est un aéronef dont la sustentation et la propulsion sont assurées par une voilure tournante, couramment appelée rotor, et entraînée par un ou plusieurs moteurs.


Name.

In Ancient Egyptian Lower Egypt was known as "mḥw" which means "north". Later on during Antiquity and the Middle Ages, Greeks and Romans called it "Κάτω Αἴγυπτος" or "Aegyptus Inferior" both meaning "Lower Egypt". Native Coptic Egyptian population carried on using the old name related to north – "Tsakhit" () or "Psanamhit" () "Northern part", which they also divided into three regions – western part called ⲛⲓⲫⲁⲓⲁⲧ "Niphaiat" ("Libyans"), central part called ⲡⲉⲧⲙⲟⲩⲣ "Badmur" ("the one which bounds, girds", Greek: "Πτιμυρις") and eastern one called ϯⲁⲣⲁⲃⲓⲁ "Diarabia" ("Arabia").

Geography.

In ancient times, Pliny the Elder, in "Natural History" (Book 5, chapter 11), said that upon reaching the delta the Nile split into seven branches (from east to west): the Pelusiac, the Tanitic, the Mendesian, the Phatnitic, the Sebennytic, the Bolbitine, and the Canopic. Today there are two principal channels that the Nile takes through the river's delta: one in the west at Rashid and one in the east at Damietta.  The delta region is well watered, crisscrossed by channels and canals.  The climate in Lower Egypt is milder than that of Upper Egypt owing primarily to its proximity to the Mediterranean Sea. Temperatures are less extreme and rainfall is more abundant.

History.

It was divided into twenty districts called nomes, the first of which was at el-Lisht. Because Lower Egypt was mostly undeveloped scrubland, filled with all types of plant life such as grasses and herbs, the organization of the nomes underwent several changes.  The capital of Lower Egypt was Memphis. Its patron goddess was the cobra goddess Wadjet. Lower Egypt was represented by the Low Red Crown "Deshret", and its symbols were the papyrus and the bee.  By about 3600 BC, Neolithic Egyptian societies along the Nile River had based their culture on the raising of crops and the domestication of animals. Shortly after 3600 BC Egyptian society began to grow and advance rapidly toward refined civilization. A new and distinctive pottery, which was related to the pottery in the Southern Levant, appeared during this time. Extensive use of copper became common during this time. The Mesopotamian process of sun-dried bricks, and architectural building principles—including the use of the arch and recessed walls for decorative effect—became popular during this time.  Concurrent with these cultural advances, a process of unification of the societies and towns of the upper Nile River, or Upper Egypt, occurred. At the same time the societies of the Nile Delta, or Lower Egypt also underwent a unification process. Warfare between Upper and Lower Egypt occurred often. During his reign in Upper Egypt, King Narmer defeated his enemies in the Delta and merged the Kingdoms of Upper and Lower Egypt under his single rule.

List of kings of the Predynastic Period of Lower Egypt.

The Palermo stone, a royal annal written in the mid Fifth Dynasty (c. 2490 BC – c. 2350 BC) records a number of kings reigning over Lower Egypt before Narmer. These are completely unattested outside these inscriptions: In contrast, the following kings are attested through archeological finds from Sinai and Lower Egypt: Double Falcon, Crocodile.

Lower Egypt ( "", "Tsakhit") is the northernmost region of Egypt, which consists of the fertile Nile Delta, between Upper Egypt and the Mediterranean Sea — from El Aiyat, south of modern-day Cairo, and Dahshur. Historically, the Nile River split into seven branches of the delta in Lower Egypt. Lower Egypt was divided into nomes and began to advance as a civilization after 3600 BC. Today, it contains two major channels that flow through the delta of the Nile River.

La Basse-Égypte est la région située au nord de l'actuelle Égypte. L'adjectif « basse » fait référence au fait que les terres du delta du Nil sont presqu'au niveau de la mer, et avec des zones marécageuses et le bord de mer.


History.

1800s.

The Leonids are famous because their meteor showers, or storms, can be among the most spectacular. Because of the storm of 1833 and the recent developments in scientific thought of the time (see for example the identification of Halley's Comet), the Leonids have had a major effect on the development of the scientific study of meteors, which had previously been thought to be atmospheric phenomena. Although it has been suggested the Leonid meteor shower and storms have been noted in ancient times, it was the meteor storm of 1833 that broke into people's modern day awareness – it was of truly superlative strength. One estimate of the peak rate is over one hundred thousand meteors an hour, but another, done as the storm abated, estimated in excess of 240,000 meteors during the nine hours of the storm, over the entire region of North America east of the Rocky Mountains.  It was marked by several nations of Native Americans: the Cheyenne established a peace treaty and the Lakota calendar was reset. Abolitionists including Harriet Tubman and Frederick Douglass as well as slave-owners took note and others. The New York Evening Post carried a series of articles on the event including reports from Canada to Jamaica, it made news in several states beyond New York and though it appeared in North America was talked about in Europe. The journalism of the event tended to rise above the partisan debates of the time and reviewed facts as they could be sought out. Abraham Lincoln commented on it years later. Near Independence, Missouri, in Clay County, a refugee Mormon community watched the meteor shower on the banks of the Missouri River after having been driven from their homes by local settlers. The founder and first leader of Mormonism, Joseph Smith, afterwards noted in his journal his belief that this event was a literal fulfillment of the word of God and a sure sign that the coming of Christ was close at hand. Though it was noted in the midwest and eastern areas it was also noted in the far west.  Denison Olmsted explained the event most accurately. After spending the last weeks of 1833 collecting information, he presented his findings in January 1834 to the "American Journal of Science and Arts", published in January–April 1834, and January 1836. He noted the shower was of short duration and was not seen in Europe, and that the meteors radiated from a point in the constellation of Leo and he speculated the meteors had originated from a cloud of particles in space. Accounts of the 1866 repeat of the Leonids counted hundreds per minute/a few thousand per hr in Europe. The Leonids were again seen in 1867, when moonlight reduced the rates to 1000 per hour. Another strong appearance of the Leonids in 1868 reached an intensity of 1000 per hour in dark skies. It was in 1866–67 that information on Comet Tempel-Tuttle was gathered pointing it out as the source of the meteor shower. When the storms failed to return in 1899, it was generally thought that the dust had moved on and storms were a thing of the past.

1900s.

Then, in 1966, a spectacular storm was seen over the Americas. Historical notes were gathered thus noting the Leonids back to 900AD. Radar studies showed the 1966 storm included a relatively high percentage of smaller particles while 1965's lower activity had a much higher proportion of larger particles. In 1981 Donald K. Yeomans of the Jet Propulsion Laboratory reviewed the history of meteor showers for the Leonids and the history of the dynamic orbit of Comet Tempel-Tuttle. A graph from it was adapted and re-published in Sky and Telescope. It showed relative positions of the Earth and Tempel-Tuttle and marks where Earth encountered dense dust. This showed that the meteoroids are mostly behind and outside the path of the comet, but paths of the Earth through the cloud of particles resulting in powerful storms were very near paths of nearly no activity. But overall the 1998 Leonids were in a favorable position so interest was rising.  Leading up to the 1998 return, an airborne observing campaign was organized to mobilize modern observing techniques by Peter Jenniskens at NASA Ames Research Center. There were also efforts to observe impacts of meteoroids, as an example of transient lunar phenomenon, on the Moon in 1999. A particular reason to observe the Moon is that our vantage from a location on Earth sees only meteors coming into the atmosphere relatively close to us while impacts on the Moon would be visible from across the Moon in a single view. The sodium tail of the Moon tripled just after the 1998 Leonid shower which was composed of larger meteoroids (which in the case of the Earth was witnessed as fireballs.) However, in 1999 the sodium tail of the Moon did not change from the Leonid impacts.  Research by Kondrat'eva, Reznikov and colleagues at Kazan University had shown how meteor storms could be accurately predicted, but for some years the worldwide meteor community remained largely unaware of these results. The work of David J. Asher, Armagh Observatory and Robert H. McNaught, Siding Spring Observatory and independently by Esko Lyytinen in 1999, following on from the Kazan research, is considered by most meteor experts as the breakthrough in modern analysis of meteor storms. Whereas previously it was hazardous to guess if there would be a storm or little activity, the predictions of Asher and McNaught timed bursts in activity down to ten minutes by narrowing down the clouds of particles to individual streams from each passage of the comet, and their trajectories amended by subsequent passage near planets. However, whether a specific meteoroid trail will be primarily composed of small or large particles, and thus the relative brightness of the meteors, was not understood. But McNaught did extend the work to examine the placement of the Moon with trails and saw a large chance of a storm impacting in 1999 from a trail while there were less direct impacts from trails in 2000 and 2001 (successive contact with trails through 2006 showed no hits.)

2000s.

Viewing campaigns resulted in spectacular footage from the 1999, 2001, and 2002 storms which produced up to 3,000 Leonid meteors per hour. Predictions for the Moon's Leonid impacts also noted that in 2000 the side of the Moon facing the stream was away from the Earth, but that impacts should be in number enough to raise a cloud of particles kicked off the Moon which could cause a detectable increase in the sodium tail of the Moon. Research using the explanation of meteor trails/streams have explained the storms of the past. The 1833 storm was not due to the recent passage of the comet, but from a direct impact with the previous 1800 dust trail. The meteoroids from the 1733 passage of Comet Tempel-Tuttle resulted in the 1866 storm and the 1966 storm was from the 1899 passage of the comet. The double spikes in Leonid activity in 2001 and in 2002 were due to the passage of the comet's dust ejected in 1767 and 1866. This ground breaking work was soon applied to other meteor showers – for example the 2004 June Bootids. Peter Jenniskens has published predictions for the next 50 years. However, a close encounter with Jupiter is expected to perturb the comet's path, and many streams, making storms of historic magnitude unlikely for many decades. Recent work tries to take into account the roles of differences in parent bodies and the specifics of their orbits, ejection velocities off the solid mass of the core of a comet, radiation pressure from the sun, the Poynting–Robertson effect, and the Yarkovsky effect on the particles of different sizes and rates of rotation to explain differences between meteor showers in terms of being predominantly fireballs or small meteors. Predictions until the end of the 21st century have been published by Mikhail Maslov.

In media.

Two appearances of the Leonids frame the story of the novel Blood Meridian by Cormac McCarthy.  The 1833 shower is referenced in the fourth section of William Faulkner's short story "The Bear," as published in his novel Go Down, Moses. As Ike reads the entries chronicling the slaves owned by his family, the recording for Tomy lists her death as June 1833, "Yr stars fell."  In "Pokémon Omega Ruby and Alpha Sapphire", the Leonid is referenced as the Litleonids meteor shower (named after the Pokémon species Litleo). This has a big impact in an event in its post game named "The Delta Episode" in which one of the meteors contain Deoxys.  The shower is part of the plot in the first episode of The Brokenwood Mysteries, a New Zealand crime series.  In season 3, Episode 8 of The Big Bang Theory, Leonard, Howard and Raj are off camping to observe the Leonid meteor shower, eat cannabis laced cookies, and end up missing the shower altogether.  In season 1, Episode 15 of "Thunderbirds Are Go", "Relic", Tracy family members, Alan and Scott, travel to the far side of the Moon to rescue one of their father's old friends from an almost-decomissioned moonbase at risk of being destroyed by the Leonid meteor shower. The series is set in the year 2060.

The Leonids ( ) are a prolific meteor shower associated with the comet Tempel–Tuttle, which are also known for their spectacular meteor storms that occur about every 33 years. The Leonids get their name from the location of their radiant in the constellation Leo: the meteors appear to radiate from that point in the sky. Their proper Greek name should be Leon"t"ids (Λεοντίδαι, "Leontídai"), but the word was initially constructed as a Greek/Latin hybrid and it has been used since. They peak in the month of November.

Les Léonides, ou Delta Léonides, sont un essaim de météoroïdes ou météores associés, observables en novembre, dont le radiant est situé dans la constellation zodiacale du Lion.


Morphology and terminology.

A stamen typically consists of a stalk called the filament and an anther which contains "microsporangia". Most commonly anthers are two-lobed and are attached to the filament either at the base or in the middle area of the anther. The sterile tissue between the lobes is called the connective, an extension of the filament containing conducting strands.It can be seen as an extension on the dorsal side of the anther. A pollen grain develops from a microspore in the microsporangium and contains the male gametophyte.  The stamens in a flower are collectively called the androecium. The androecium can consist of as few as one-half stamen (i.e. a single locule) as in "Canna" species or as many as 3,482 stamens which have been counted in "Carnegiea gigantea". The androecium in various species of plants forms a great variety of patterns, some of them highly complex. It generally surrounds the gynoecium and is surrounded by the perianth. A few members of the family Triuridaceae, particularly "Lacandonia schismatica", are exceptional in that their gynoecia surround their androecia.

Variation in morphology.

Depending on the species of plant, some or all of the stamens in a flower may be attached to the petals or to the floral axis. They also may be free-standing or fused to one another in many different ways, including fusion of some but not all stamens. The filaments may be fused and the anthers free, or the filaments free and the anthers fused. Rather than there being two locules, one locule of a stamen may fail to develop, or alternatively the two locules may merge late in development to give a single locule. Extreme cases of stamen fusion occur in some species of "Cyclanthera" in the family Cucurbitaceae and in section "Cyclanthera" of genus "Phyllanthus" (family Euphorbiaceae) where the stamens form a ring around the gynoecium, with a single locule.

Pollen production.

A typical anther contains four microsporangia. The "microsporangia" form sacs or pockets ("locules") in the anther (anther sacs or pollen sacs). The two separate locules on each side of an anther may fuse into a single locule. Each microsporangium is lined with a nutritive tissue layer called the "tapetum" and initially contains diploid pollen mother cells. These undergo meiosis to form haploid spores. The spores may remain attached to each other in a tetrad or separate after meiosis. Each microspore then divides mitotically to form an immature microgametophyte called a pollen grain.  The pollen is eventually released when the anther forms openings (dehisces). These may consist of longitudinal slits, pores, as in the heath family (Ericaceae), or by valves, as in the barberry family (Berberidaceae). In some plants, notably members of Orchidaceae and Asclepiadoideae, the pollen remains in masses called pollinia, which are adapted to attach to particular pollinating agents such as birds or insects. More commonly, mature pollen grains separate and are dispensed by wind or water, pollinating insects, birds or other pollination vectors.  Pollen of angiosperms must be transported to the stigma, the receptive surface of the "carpel", of a compatible flower, for successful pollination to occur. After arriving, the pollen grain (an immature microgametophyte) typically completes its development. It may grow a pollen tube and undergoing mitosis to produce two sperm nuclei.

Sexual reproduction in plants.

In the typical flower (that is, in the majority of flowering plant species) each flower has both carpels and stamens. In some species, however, the flowers are unisexual with only carpels or stamens. (monoecious = both types of flowers found on the same plant; dioecious = the two types of flower found only on different plants). A flower with only stamens is called androecious. A flower with only carpels is called gynoecious.  A flower having only functional stamens and lacking functional carpels is called a staminate flower, or (inaccurately) male. A plant with only functional carpels is called pistillate, or (inaccurately) female.  An abortive or rudimentary stamen is called a staminodium or staminode, such as in "Scrophularia nodosa".  The carpels and stamens of orchids are fused into a column. The top part of the column is formed by the anther, which is covered by an anther cap.  Stamens can also be adnate (fused or joined from more than one whorl): They can have different lengths from each other: or respective to the rest of the flower (perianth): They may be arranged in one of two different patterns: They may be arranged, with respect to the petals:  Where the connective is very small, or imperceptible, the anther lobes are close together, and the connective is referred to as discrete, e.g. "Euphorbia" pp., "Adhatoda zeylanica". Where the connective separates the anther lobes, it is called divaricate, e.g. "Tilia", "Justicia gendarussa". The connective may also be a long and stalk-like, crosswise on the filament, this is a distractile connective, e.g. "Salvia". The connective may also bear appendages, and is called appendiculate, e.g. "Nerium odorum" and some other species of Apocynaceae. In "Nerium", the appendages are united as a staminal corona. A column formed from the fusion of multiple filaments is known as an androphore. Stamens can be connate (fused or joined in the same whorl) as follows:  Anther shapes are variously described by terms such as linear, rounded, sagittate, sinuous, or reniform.

Descriptive terms.

The anther can be attached to the filament's connective in two ways:

The stamen (plural "stamina" or "stamens") is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium.

Une étamine est l'unité de l'appareil reproducteur mâle (l'androcée) chez les plantes à fleurs (ou angiospermes). Cet organe assure avec les carpelles la reproduction.


Politics and wars.

Prominent political events.

Africa.

Hertzog of South Africa, whose National Party had won the 1929 election alone, after splitting with the Labour Party, received much of the blame for the devastating economic impact of the depression.

Assassinations and attempts.

Prominent assassinations, targeted killings, and assassination attempts include:

Science and technology.

Technology.

Many technological advances occurred in the 1930s, including:  In the art of film making, the Golden Age of Hollywood entered a whole decade, after the advent of talking pictures ("talkies") in 1927 and full-color films in 1930: more than 50 classic films were made in the 1930s:

Popular culture.

Film.

most notable were "Gone With The Wind" and "The Wizard of Oz." In 1930, Howard Hughes produces Hell's Angels (film), the first movie blockbuster to be produced outside of a professional studio, independently, as well as becoming the most expensive movie made, at that time, costing roughly 4 million dollars, and taking four years to make. Hell's Angels was an epic masterpiece, valued, and relative to the people at those specific times, of harsh war.

Fashion.

The most characteristic North American fashion trend from the 1930s to 1945 was attention at the shoulder, with butterfly sleeves and banjo sleeves, and exaggerated shoulder pads for both men and women by the 1940s. The period also saw the first widespread use of man-made fibers, especially rayon for dresses and viscose for linings and lingerie, and synthetic nylon stockings. The zipper became widely used. These essentially U.S. developments were echoed, in varying degrees, in Britain and Europe. Suntans (called at the time "sunburns") became fashionable in the early 1930s, along with travel to the resorts along the Mediterranean, in the Bahamas, and on the east coast of Florida where one can acquire a tan, leading to new categories of clothes: white dinner jackets for men and beach pajamas, halter tops, and bare midriffs for women.  Fashion trendsetters in the period included The Prince of Wales (King Edward VIII from January 1936 until his abdication that December) and his companion Wallis Simpson (the Duke and Duchess of Windsor from their marriage in June 1937), socialites like Nicolas de Gunzburg, Daisy Fellowes and Mona von Bismarck and such Hollywood movie stars as Fred Astaire, Carole Lombard and Joan Crawford.

Visual arts.

Social Realism became an important art movement during the Great Depression in the United States in the 1930s. Social realism generally portrayed imagery with socio-political meaning. Other related American artistic movements of the 1930s were American scene painting and Regionalism which were generally depictions of rural America, and historical images drawn from American history. Precisionism with its depictions of industrial America was also a popular art movement during the 1930s in the USA. During the Great Depression the art of photography played an important role in the Social Realist movement. The work of Dorothea Lange, Walker Evans, Margaret Bourke-White, Lewis Hine, Edward Steichen, Gordon Parks, Arthur Rothstein, Marion Post Wolcott, Doris Ulmann, Berenice Abbott, Aaron Siskind, Russell Lee, Ben Shahn (as a photographer) among several others were particularly influential.  The Works Progress Administration part of the Roosevelt Administration's New Deal sponsored the Federal Art Project, the Public Works of Art Project, and the Section of Painting and Sculpture which employed many American artists and helped them to make a living during the Great Depression.  Mexican muralism was a Mexican art movement that took place primarily in the 1930s. The movement stands out historically because of its political undertones, the majority of which of a Marxist nature, or related to a social and political situation of post-revolutionary Mexico. Also in Latin America Symbolism and Magic Realism were important movements.  In Europe during the 1930s and the Great Depression, Surrealism, late Cubism, the Bauhaus, De Stijl, Dada, German Expressionism, Symbolist and modernist painting in various guises characterized the art scene in Paris and elsewhere.

People.

Criminals.

Prominent criminals of the Great Depression:

See also.

Timeline.

The following articles contain brief timelines which list the most prominent events of the decade:  1930 • 1931 • 1932 • 1933 • 1934 • 1935 • 1936 • 1937 • 1938 • 1939

The 1930s (pronounced "nineteen-thirties", commonly abbreviated as the "Thirties") was a decade of the Gregorian calendar that began on January 1, 1930, and ended on December 31, 1939.

Les années 1930 couvrent la période de 1930 à 1939. Cette décennie est marquée par des famines, l’amplification de la crise économique issue du krach boursier de 1929, la montée des extrémismes, des guerres et des tensions internationales, de la xénophobie et de l’antisémitisme, et finalement le déclenchement de la Seconde Guerre mondiale.


History.

The origins of machine translation can be traced back to the work of Al-Kindi, a 9th-century Arabic cryptographer who developed techniques for systemic language translation, including cryptanalysis, frequency analysis, and probability and statistics, which are used in modern machine translation. The idea of machine translation later appeared in the 17th century. In 1629, René Descartes proposed a universal language, with equivalent ideas in different tongues sharing one symbol.  The field of machine translation was founded with Warren Weaver's Memorandum on Translation (1949). The first researcher in the field, Yehosha Bar-Hillel, began his research at MIT (1951). A Georgetown University MT research team followed (1951) with a public demonstration of its Georgetown-IBM experiment system in 1954. MT research programs popped up in Japan and Russia (1955), and the first MT conference was held in London (1956). Researchers continued to join the field as the Association for Machine Translation and Computational Linguistics was formed in the U.S. (1962) and the National Academy of Sciences formed the Automatic Language Processing Advisory Committee (ALPAC) to study MT (1964). Real progress was much slower, however, and after the ALPAC report (1966), which found that the ten-year-long research had failed to fulfill expectations, funding was greatly reduced. According to a 1972 report by the Director of Defense Research and Engineering (DDR&E), the feasibility of large-scale MT was reestablished by the success of the Logos MT system in translating military manuals into Vietnamese during that conflict.  The French Textile Institute also used MT to translate abstracts from and into French, English, German and Spanish (1970); Brigham Young University started a project to translate Mormon texts by automated translation (1971); and Xerox used SYSTRAN to translate technical manuals (1978). Beginning in the late 1980s, as computational power increased and became less expensive, more interest was shown in statistical models for machine translation. MT became more popular after the advent of computers. SYSTRAN's first implementation system was implemented in 1988 by the online service of the French Postal Service called Minitel. Various MT companies were also launched, including Trados (1984), which was the first to develop and market translation memory technology (1989). The first commercial MT system for Russian / English / German-Ukrainian was developed at Kharkov State University (1991).  MT on the web started with SYSTRAN offering free translation of small texts (1996), followed by AltaVista Babelfish, which racked up 500,000 requests a day (1997). Franz Josef Och (the future head of Translation Development AT Google) won DARPA's speed MT competition (2003). More innovations during this time included MOSES, the open-source statistical MT engine (2007), a text/SMS translation service for mobiles in Japan (2008), and a mobile phone with built-in speech-to-speech translation functionality for English, Japanese and Chinese (2009). Recently, Google announced that Google Translate translates roughly enough text to fill 1 million books in one day (2012).  The idea of using digital computers for translation of natural languages was proposed as early as 1946 by A. D. Booth and possibly others. Warren Weaver wrote an important memorandum "Translation" in 1949. The Georgetown experiment was by no means the first such application, and a demonstration was made in 1954 on the APEXC machine at Birkbeck College (University of London) of a rudimentary translation of English into French. Several papers on the topic were published at the time, and even articles in popular journals (for example an article by Cleave and Zacharov in the September 1955 issue of "Wireless World"). A similar application, also pioneered at Birkbeck College at the time, was reading and composing Braille texts by computer.

Translation process.

The human translation process may be described as:  Behind this ostensibly simple procedure lies a complex cognitive operation. To decode the meaning of the source text in its entirety, the translator must interpret and analyse all the features of the text, a process that requires in-depth knowledge of the grammar, semantics, syntax, idioms, etc., of the source language, as well as the culture of its speakers. The translator needs the same in-depth knowledge to re-encode the meaning in the target language.  Therein lies the challenge in machine translation: how to program a computer that will "understand" a text as a person does, and that will "create" a new text in the target language that sounds as if it has been written by a person.  In its most general application, this is beyond current technology. Though it works much faster, no automated translation program or procedure, with no human participation, can produce output even close to the quality a human translator can produce. What it can do, however, is provide a general, though imperfect, approximation of the original text, getting the "gist" of it (a process called "gisting"). This is sufficient for many purposes, including making best use of the finite and expensive time of a human translator, reserved for those cases in which total accuracy is indispensable.  This problem may be approached in a number of ways, through the evolution of which accuracy has improved.

Approaches.

Machine translation can use a method based on linguistic rules, which means that words will be translated in a linguistic way – the most suitable (orally speaking) words of the target language will replace the ones in the source language.  It is often argued that the success of machine translation requires the problem of natural language understanding to be solved first.  Generally, rule-based methods parse a text, usually creating an intermediary, symbolic representation, from which the text in the target language is generated. According to the nature of the intermediary representation, an approach is described as interlingual machine translation or transfer-based machine translation. These methods require extensive lexicons with morphological, syntactic, and semantic information, and large sets of rules.  Given enough data, machine translation programs often work well enough for a native speaker of one language to get the approximate meaning of what is written by the other native speaker. The difficulty is getting enough data of the right kind to support the particular method. For example, the large multilingual corpus of data needed for statistical methods to work is not necessary for the grammar-based methods. But then, the grammar methods need a skilled linguist to carefully design the grammar that they use.  To translate between closely related languages, the technique referred to as rule-based machine translation may be used.

Rule-based.

The rule-based machine translation paradigm includes transfer-based machine translation, interlingual machine translation and dictionary-based machine translation paradigms. This type of translation is used mostly in the creation of dictionaries and grammar programs. Unlike other methods, RBMT involves more information about the linguistics of the source and target languages, using the morphological and syntactic rules and semantic analysis of both languages. The basic approach involves linking the structure of the input sentence with the structure of the output sentence using a parser and an analyzer for the source language, a generator for the target language, and a transfer lexicon for the actual translation. RBMT's biggest downfall is that everything must be made explicit: orthographical variation and erroneous input must be made part of the source language analyser in order to cope with it, and lexical selection rules must be written for all instances of ambiguity. Adapting to new domains in itself is not that hard, as the core grammar is the same across domains, and the domain-specific adjustment is limited to lexical selection adjustment.

Transfer-based machine translation.

Transfer-based machine translation is similar to interlingual machine translation in that it creates a translation from an intermediate representation that simulates the meaning of the original sentence. Unlike interlingual MT, it depends partially on the language pair involved in the translation.

Interlingual.

Interlingual machine translation is one instance of rule-based machine-translation approaches. In this approach, the source language, i.e. the text to be translated, is transformed into an interlingual language, i.e. a "language neutral" representation that is independent of any language. The target language is then generated out of the interlingua. One of the major advantages of this system is that the interlingua becomes more valuable as the number of target languages it can be turned into increases. However, the only interlingual machine translation system that has been made operational at the commercial level is the KANT system (Nyberg and Mitamura, 1992), which is designed to translate Caterpillar Technical English (CTE) into other languages.

Dictionary-based.

Machine translation can use a method based on dictionary entries, which means that the words will be translated as they are by a dictionary.

Statistical.

Statistical machine translation tries to generate translations using statistical methods based on bilingual text corpora, such as the Canadian Hansard corpus, the English-French record of the Canadian parliament and EUROPARL, the record of the European Parliament. Where such corpora are available, good results can be achieved translating similar texts, but such corpora are still rare for many language pairs. The first statistical machine translation software was CANDIDE from IBM. Google used SYSTRAN for several years, but switched to a statistical translation method in October 2007. In 2005, Google improved its internal translation capabilities by using approximately 200 billion words from United Nations materials to train their system; translation accuracy improved. Google Translate and similar statistical translation programs work by detecting patterns in hundreds of millions of documents that have previously been translated by humans and making intelligent guesses based on the findings. Generally, the more human-translated documents available in a given language, the more likely it is that the translation will be of good quality. Newer approaches into Statistical Machine translation such as METIS II and PRESEMT use minimal corpus size and instead focus on derivation of syntactic structure through pattern recognition. With further development, this may allow statistical machine translation to operate off of a monolingual text corpus. SMT's biggest downfall includes it being dependent upon huge amounts of parallel texts, its problems with morphology-rich languages (especially with translating "into" such languages), and its inability to correct singleton errors.

Example-based.

Example-based machine translation (EBMT) approach was proposed by Makoto Nagao in 1984. Example-based machine translation is based on the idea of analogy. In this approach, the corpus that is used is one that contains texts that have already been translated. Given a sentence that is to be translated, sentences from this corpus are selected that contain similar sub-sentential components. The similar sentences are then used to translate the sub-sentential components of the original sentence into the target language, and these phrases are put together to form a complete translation.

Hybrid MT.

Hybrid machine translation (HMT) leverages the strengths of statistical and rule-based translation methodologies. Several MT organizations claim a hybrid approach that uses both rules and statistics. The approaches differ in a number of ways: More recently, with the advent of Neural MT, a new version of hybrid machine translation is emerging that combines the benefits of rules, statistical and neural machine translation. The approach allows benefitting from pre- and post-processing in a rule guided workflow as well as benefitting from NMT and SMT. The downside is the inherent complexity which makes the approach suitable only for specific use cases. One of the proponents of this approach for complex use cases is Omniscien Technologies.

Neural MT.

A deep learning based approach to MT, neural machine translation has made rapid progress in recent years, and Google has announced its translation services are now using this technology in preference to its previous statistical methods. Microsoft team reached human parity on WMT-2017 in 2018 and this was a historical milestone.

Major issues.

Disambiguation.

Word-sense disambiguation concerns finding a suitable translation when a word can have more than one meaning. The problem was first raised in the 1950s by Yehoshua Bar-Hillel. He pointed out that without a "universal encyclopedia", a machine would never be able to distinguish between the two meanings of a word. Today there are numerous approaches designed to overcome this problem. They can be approximately divided into "shallow" approaches and "deep" approaches.  Shallow approaches assume no knowledge of the text. They simply apply statistical methods to the words surrounding the ambiguous word. Deep approaches presume a comprehensive knowledge of the word. So far, shallow approaches have been more successful.  Claude Piron, a long-time translator for the United Nations and the World Health Organization, wrote that machine translation, at its best, automates the easier part of a translator's job; the harder and more time-consuming part usually involves doing extensive research to resolve ambiguities in the source text, which the grammatical and lexical exigencies of the target language require to be resolved:  The ideal deep approach would require the translation software to do all the research necessary for this kind of disambiguation on its own; but this would require a higher degree of AI than has yet been attained. A shallow approach which simply guessed at the sense of the ambiguous English phrase that Piron mentions (based, perhaps, on which kind of prisoner-of-war camp is more often mentioned in a given corpus) would have a reasonable chance of guessing wrong fairly often. A shallow approach that involves "ask the user about each ambiguity" would, by Piron's estimate, only automate about 25% of a professional translator's job, leaving the harder 75% still to be done by a human.

Non-standard speech.

One of the major pitfalls of MT is its inability to translate non-standard language with the same accuracy as standard language. Heuristic or statistical based MT takes input from various sources in standard form of a language. Rule-based translation, by nature, does not include common non-standard usages. This causes errors in translation from a vernacular source or into colloquial language. Limitations on translation from casual speech present issues in the use of machine translation in mobile devices.

Named entities.

Name entities, in narrow sense, refer to concrete or abstract entities in the real world including people, organizations, companies, places etc. It also refers to expressing of time, space, quantity such as 1 July 2011, $79.99 and so on.  Named entities occur in the text being analyzed in statistical machine translation. The initial difficulty that arises in dealing with named entities is simply identifying them in the text. Consider the list of names common in a particular language to illustrate this – the most common names are different for each language and also are constantly changing. If named entities cannot be recognized by the machine translator, they may be erroneously translated as common nouns, which would most likely not affect the BLEU rating of the translation but would change the text's human readability. It is also possible that, when not identified, named entities will be omitted from the output translation, which would also have implications for the text's readability and message.  Another way to deal with named entities is to use transliteration instead of translation, meaning that you find the letters in the target language that most closely correspond to the name in the source language. There have been attempts to incorporate this into machine translation by adding a transliteration step into the translation procedure. However, these attempts still have their problems and have even been cited as worsening the quality of translation. Named entities were still identified incorrectly, with words not being transliterated when they should or being transliterated when they shouldn't. For example, for "Southern California" the first word should be translated directly, while the second word should be transliterated. However, machines would often transliterate both because they treated them as one entity. Words like these are hard for machine translators, even those with a transliteration component, to process.  The lack of attention to the issue of named entity translation has been recognized as potentially stemming from a lack of resources to devote to the task in addition to the complexity of creating a good system for named entity translation. One approach to named entity translation has been to transliterate, and not translate, those words. A second is to create a "do-not-translate" list, which has the same end goal – transliteration as opposed to translation. Both of these approaches still rely on the correct identification of named entities, however.  A third approach to successful named entity translation is a class-based model. In this method, named entities are replaced with a token to represent the class they belong to. For example, "Ted" and "Erica" would both be replaced with "person" class token. In this way the statistical distribution and use of person names in general can be analyzed instead of looking at the distributions of "Ted" and "Erica" individually. A problem that the class based model solves is that the probability of a given name in a specific language will not affect the assigned probability of a translation. A study by Stanford on improving this area of translation gives the examples that different probabilities will be assigned to "David is going for a walk" and "Ankit is going for a walk" for English as a target language due to the different number of occurrences for each name in the training data. A frustrating outcome of the same study by Stanford (and other attempts to improve named recognition translation) is that many times, a decrease in the BLEU scores for translation will result from the inclusion of methods for named entity translation.

Translation from multiparallel sources.

Some work has been done in the utilization of multiparallel corpora, that is a body of text that has been translated into 3 or more languages. Using these methods, a text that has been translated into 2 or more languages may be utilized in combination to provide a more accurate translation into a third language compared with if just one of those source languages were used alone.

Ontologies in MT.

An ontology is a formal representation of knowledge which includes the concepts (such as objects, processes etc.) in a domain and some relations between them. If the stored information is of linguistic nature, one can speak of a lexicon. In NLP, ontologies can be used as a source of knowledge for machine translation systems. With access to a large knowledge base, systems can be enabled to resolve many (especially lexical) ambiguities on their own. In the following classic examples, as humans, we are able to interpret the prepositional phrase according to the context because we use our world knowledge, stored in our lexicons: A machine translation system initially would not be able to differentiate between the meanings because syntax does not change. With a large enough ontology as a source of knowledge however, the possible interpretations of ambiguous words in a specific context can be reduced. Other areas of usage for ontologies within NLP include information retrieval, information extraction and text summarization.

Building ontologies.

The ontology generated for the PANGLOSS knowledge-based machine translation system in 1993 may serve as an example of how an ontology for NLP purposes can be compiled:

Applications.

While no system provides the holy grail of fully automatic high-quality machine translation of unrestricted text, many fully automated systems produce reasonable output. The quality of machine translation is substantially improved if the domain is restricted and controlled.  Despite their inherent limitations, MT programs are used around the world. Probably the largest institutional user is the European Commission. The project, for example, coordinated by the University of Gothenburg, received more than 2.375 million euros project support from the EU to create a reliable translation tool that covers a majority of the EU languages. The further development of MT systems comes at a time when budget cuts in human translation may increase the EU's dependency on reliable MT programs. The European Commission contributed 3.072 million euros (via its ISA programme) for the creation of MT@EC, a statistical machine translation program tailored to the administrative needs of the EU, to replace a previous rule-based machine translation system.  In 2005, Google claimed that promising results were obtained using a proprietary statistical machine translation engine. The statistical translation engine used in the Google language tools for Arabic <-> English and Chinese <-> English had an overall score of 0.4281 over the runner-up IBM's BLEU-4 score of 0.3954 (Summer 2006) in tests conducted by the National Institute for Standards and Technology.  With the recent focus on terrorism, the military sources in the United States have been investing significant amounts of money in natural language engineering. "In-Q-Tel" (a venture capital fund, largely funded by the US Intelligence Community, to stimulate new technologies through private sector entrepreneurs) brought up companies like Language Weaver. Currently the military community is interested in translation and processing of languages like Arabic, Pashto, and Dari. Within these languages, the focus is on key phrases and quick communication between military members and civilians through the use of mobile phone apps. The Information Processing Technology Office in DARPA hosts programs like TIDES and Babylon translator. US Air Force has awarded a $1 million contract to develop a language translation technology.  The notable rise of social networking on the web in recent years has created yet another niche for the application of machine translation software – in utilities such as Facebook, or instant messaging clients such as Skype, GoogleTalk, MSN Messenger, etc. – allowing users speaking different languages to communicate with each other. Machine translation applications have also been released for most mobile devices, including mobile telephones, pocket PCs, PDAs, etc. Due to their portability, such instruments have come to be designated as mobile translation tools enabling mobile business networking between partners speaking different languages, or facilitating both foreign language learning and unaccompanied traveling to foreign countries without the need of the intermediation of a human translator.  Despite being labelled as an unworthy competitor to human translation in 1966 by the Automated Language Processing Advisory Committee put together by the United States government, the quality of machine translation has now been improved to such levels that its application in online collaboration and in the medical field are being investigated. The application of this technology in medical settings where human translators are absent is another topic of research, but difficulties arise due to the importance of accurate translations in medical diagnoses.

Evaluation.

There are many factors that affect how machine translation systems are evaluated. These factors include the intended use of the translation, the nature of the machine translation software, and the nature of the translation process.  Different programs may work well for different purposes. For example, statistical machine translation (SMT) typically outperforms example-based machine translation (EBMT), but researchers found that when evaluating English to French translation, EBMT performs better. The same concept applies for technical documents, which can be more easily translated by SMT because of their formal language.  In certain applications, however, e.g., product descriptions written in a controlled language, a dictionary-based machine-translation system has produced satisfactory translations that require no human intervention save for quality inspection.  There are various means for evaluating the output quality of machine translation systems. The oldest is the use of human judges to assess a translation's quality. Even though human evaluation is time-consuming, it is still the most reliable method to compare different systems such as rule-based and statistical systems. Automated means of evaluation include BLEU, NIST, METEOR, and LEPOR.  Relying exclusively on unedited machine translation ignores the fact that communication in human language is context-embedded and that it takes a person to comprehend the context of the original text with a reasonable degree of probability. It is certainly true that even purely human-generated translations are prone to error. Therefore, to ensure that a machine-generated translation will be useful to a human being and that publishable-quality translation is achieved, such translations must be reviewed and edited by a human. The late Claude Piron wrote that machine translation, at its best, automates the easier part of a translator's job; the harder and more time-consuming part usually involves doing extensive research to resolve ambiguities in the source text, which the grammatical and lexical exigencies of the target language require to be resolved. Such research is a necessary prelude to the pre-editing necessary in order to provide input for machine-translation software such that the output will not be meaningless.  In addition to disambiguation problems, decreased accuracy can occur due to varying levels of training data for machine translating programs. Both example-based and statistical machine translation rely on a vast array of real example sentences as a base for translation, and when too many or too few sentences are analyzed accuracy is jeopardized. Researchers found that when a program is trained on 203,529 sentence pairings, accuracy actually decreases. The optimal level of training data seems to be just over 100,000 sentences, possibly because as training data increases, the number of possible sentences increases, making it harder to find an exact translation match.

Using machine translation as a teaching tool.

Although there have been concerns about machine translation's accuracy, Dr. Ana Nino of the University of Manchester has researched some of the advantages in utilizing machine translation in the classroom. One such pedagogical method is called using "MT as a Bad Model." MT as a Bad Model forces the language learner to identify inconsistencies or incorrect aspects of a translation; in turn, the individual will (hopefully) possess a better grasp of the language. Dr. Nino cites that this teaching tool was implemented in the late 1980s. At the end of various semesters, Dr. Nino was able to obtain survey results from students who had used MT as a Bad Model (as well as other models.) Overwhelmingly, students felt that they had observed improved comprehension, lexical retrieval, and increased confidence in their target language.

Machine translation and signed languages.

In the early 2000s, options for machine translation between spoken and signed languages were severely limited. It was a common belief that deaf individuals could use traditional translators. However, stress, intonation, pitch, and timing are conveyed much differently in spoken languages compared to signed languages. Therefore, a deaf individual may misinterpret or become confused about the meaning of written text that is based on a spoken language.  Researchers Zhao, et al. (2000), developed a prototype called TEAM (translation from English to ASL by machine) that completed English to American Sign Language (ASL) translations. The program would first analyze the syntactic, grammatical, and morphological aspects of the English text. Following this step, the program accessed a sign synthesizer, which acted as a dictionary for ASL. This synthesizer housed the process one must follow to complete ASL signs, as well as the meanings of these signs. Once the entire text is analyzed and the signs necessary to complete the translation are located in the synthesizer, a computer generated human appeared and would use ASL to sign the English text to the user.

Copyright.

Only works that are original are subject to copyright protection, so some scholars claim that machine translation results are not entitled to copyright protection because MT does not involve creativity. The copyright at issue is for a derivative work; the author of the original work in the original language does not lose his rights when a work is translated: a translator must have permission to publish a translation.

Machine translation, sometimes referred to by the abbreviation MT (not to be confused with computer-aided translation, machine-aided human translation (MAHT) or interactive translation), is a sub-field of computational linguistics that investigates the use of software to translate text or speech from one language to another.

La traduction automatique désigne la traduction d'un texte (ou d'une conversation audio, en direct ou en différé) entièrement réalisée par un ou plusieurs programmes informatiques, sans qu'un traducteur humain n'ait à intervenir. On la distingue de la traduction assistée par ordinateur où la traduction est en partie manuelle, éventuellement de façon interactive avec la machine.


Etymology.

The word "Minnesota" comes from the Dakota name for the Minnesota River, which got its name from one of two words in Dakota: "mní sóta", which means "clear blue water", or "Mníssota", which means "cloudy water". Dakota people demonstrated

Geography.

Minnesota is the second northernmost U.S. state (after Alaska) and northernmost contiguous state. The isolated Northwest Angle in Lake of the Woods county is the only part of the 48 contiguous states north of the 49th parallel. The state is part of the U.S. region known as the Upper Midwest and part of North America's Great Lakes Region. It shares a Lake Superior water border with Michigan and a land and water border with Wisconsin to the east. Iowa is to the south, North Dakota and South Dakota are to the west, and the Canadian provinces of Ontario and Manitoba are to the north. With, or approximately 2.25% of the United States, Minnesota is the 12th-largest state.

Geology.

Minnesota has some of the earth's oldest rocks, gneisses that are about 3.6 billion years old (80% as old as the planet). About 2.7 billion years ago basaltic lava poured out of cracks in the floor of the primordial ocean; the remains of this volcanic rock formed the Canadian Shield in northeast Minnesota. The roots of these volcanic mountains and the action of Precambrian seas formed the Iron Range of northern Minnesota. Since a period of volcanism 1.1 billion years ago, Minnesota's geological activity has been more subdued, with no volcanism or mountain formation, but with repeated incursions of the sea, which left behind multiple strata of sedimentary rock.  In more recent times, massive ice sheets at least one kilometer thick ravaged the state's landscape and sculpted its terrain. The Wisconsin glaciation left 12,000 years ago. These glaciers covered all of Minnesota except the far southeast, an area characterized by steep hills and streams that cut into the bedrock. This area is known as the Driftless Zone for its absence of glacial drift. Much of the remainder of the state has 50 feet (15 m) or more of glacial

Flora and fauna.

Minnesota has four ecological provinces: prairie parkland, in the southwestern and western parts of the state; the eastern broadleaf forest (Big Woods) in the southeast, extending in a narrowing strip to the state's northwestern part, where it transitions into tallgrass aspen parkland; and the northern Laurentian mixed forest, a transitional forest between the northern boreal forest and the broadleaf forests to the south. These northern forests are a vast wilderness of pine and spruce trees mixed with patchy stands of birch and poplar.  Much of Minnesota's northern forest has undergone logging, leaving only a few patches of old growth forest today in areas such as in the Chippewa National Forest and the Superior National Forest, where the Boundary Waters

Climate.

Minnesota experiences temperature extremes characteristic of its continental climate, with cold winters and hot summers. The lowest temperature recorded was at Tower on February 2, 1996, and the highest was at Moorhead on July 6, 1936. Meteorological events include rain, snow, blizzards,

Protected lands.

Minnesota's first state park, Itasca State Park, was established in 1891, and is the source of the Mississippi River. Today Minnesota has 72 state parks and recreation areas, 58 state forests covering about four million acres (16,000 km), and numerous state wildlife preserves, all managed by the Minnesota Department of

History.

Before European settlement of North America, a subculture of Sioux called the Dakota people lived in Minnesota. As Europeans settled the east coast, Native Americans moved away from them, causing migration of the Anishinaabe (also known as Ojibwe) and other Native Americans into the Minnesota area. The first Europeans in the area were French voyageur fur traders who arrived in the 17th century and began using the Grand Portage to access trapping and trading areas further inland. Late that century, Anishinaabe migrated westward to Minnesota, causing tensions with the Dakota people. Explorers such as Daniel Greysolon, Sieur du Lhut, Father Louis Hennepin, Jonathan Carver, Henry Schoolcraft, and Joseph Nicollet mapped the state.  The region was part of Spanish Louisiana from 1762 to 1802. The portion of the state east of the Mississippi River became part of the United States at the end of the American Revolutionary War, when the Second Treaty of Paris was signed. Land west of the Mississippi was acquired with the Louisiana Purchase, though part of the Red River Valley was disputed until the Treaty of 1818. By the late 1700s, the North West Company had established the post of Fort Charlotte at the Lake Superior end of the Grand Portage. It moved 50 miles northeast to Fort William in 1803. In 1805 Zebulon Pike bargained with Native Americans to acquire land at the confluence of the Minnesota and Mississippi rivers. The construction of Fort Snelling followed between 1819 and 1825. Its soldiers built a grist mill and a sawmill at Saint Anthony Falls, the first of the water-powered industries around which the city of Minneapolis later grew. Meanwhile, squatters, government officials, and sight-seers had settled near the fort. In 1839 the army forced them to move downriver and they settled in the area that became St. Paul. Minnesota Territory was formed on March 3, 1849. The first territorial legislature (held September 2, 1849) was dominated by men from New England or of New England ancestry. Thousands of people had come to build farms and cut timber, and Minnesota became the 32nd U.S. state on May 11, 1858. The founding population was so overwhelmingly of New England origins that the state was dubbed "the New

Cities and towns.

Saint Paul, in east-central Minnesota along the banks of the Mississippi River, has been Minnesota's capital city since 1849, first as capital of the Territory of Minnesota, and then as the state capital since 1858.  Saint Paul is adjacent to Minnesota's most populous city, Minneapolis; they and their suburbs are collectively known as the Twin Cities metropolitan area, the country's 16th-largest metropolitan area and home to about 55 percent of the state's population. The

Demographics.

Population.

From fewer than 6,120 white settlers in 1850, Minnesota's official population grew to over 1.7 million by 1900. Each of the next six decades saw a 15 percent increase in population, reaching 3.4 million in 1960. Growth then slowed, rising 11 percent to 3.8 million in 1970, and an average of 9percent over the next three decades to 4.9 million in the 2000 Census.  The United States Census Bureau estimates the population of Minnesota was 5,639,632 on July 1, 2019, a 6.33 percent increase since the 2010 United States Census. The rate of population change, and age and gender distributions, approximate the national average. Minnesota's center of population is in Hennepin County.  As of the 2010 Census

Religion.

The majority of Minnesotans are Protestants, including a large Lutheran contingent, owing to the state's largely Northern European ethnic makeup. Roman Catholics (of largely German, Irish, French and Slavic descent) make up the largest single Christian denomination. A 2010 survey by the Pew Forum on Religion and Public Life showed that 32 percent of Minnesotans were affiliated with Mainline Protestant traditions, 21 percent were Evangelical Protestants, 28 percent Roman Catholic, 1percent each Jewish, Muslim, Buddhist, and Black Protestant, and smaller amounts of other faiths,

Economy.

Once primarily a producer of raw materials, Minnesota's economy has transformed to emphasize finished products and services. Perhaps the most significant characteristic of the economy is its diversity; the relative outputs of its business sectors closely match the United States as a whole. Minnesota's economy had a gross domestic product of $262 billion in 2008, with 33 of the United States' top 1,000 publicly traded companies by revenue headquartered in Minnesota, including Target, UnitedHealth Group, 3M, General Mills, U.S. Bancorp, Ameriprise, Hormel, Land O' Lakes, SuperValu, Best Buy, and Valspar. Private companies based in Minnesota include Cargill, the largest privately owned company in the United States, and Carlson Companies, the parent company of Radisson Hotels.  Minnesota's per capita personal income in 2008 was $42,772, the tenth-highest in the nation. Its three-year median household income from 2002 to 2004 was $55,914, ranking fifth in the U.S. and first among the 36 states not on the Atlantic coast.  As of December 2018 the state's unemployment rate was 2.8 percent.

Industry and commerce.

Minnesota's earliest industries were fur trading and agriculture. Minneapolis grew around the flour mills powered by St. Anthony Falls. Although less than one percent of the population is now employed in the agricultural sector, it remains a major part of the state's economy, ranking sixth in the nation in the value of products sold. The state is the nation's largest producer of sugar beets, sweet corn, and peas for processing, and farm-raised turkeys. Minnesota is also a large producer of corn and soybeans, and has the most food cooperatives per capita in the United States. Forestry remains strong, including

Energy use and production.

Minnesota produces ethanol fuel and is the first to mandate its use, a ten percent mix (E10). In 2019 there were more than 411 service stations supplying E85 fuel, comprising 85 percent ethanol and 15 percent gasoline. A two percent biodiesel

State taxes.

Minnesota has a progressive income tax structure; the four brackets of state income tax rates are 5.35, 7.05, 7.85 and 9.85 percent. As of 2008 Minnesota was ranked 12th in the nation in per capita total state and local taxes. In 2008 Minnesotans paid 10.2 percent of their income in state and local taxes; the U.S. average was 9.7 percent.

Culture.

Fine and performing arts.

Minnesota's leading fine art museums include the Minneapolis Institute of Art, the Walker Art Center, the Frederick R. Weisman Art Museum, and The Museum of Russian Art (TMORA). All are in Minneapolis. The Minnesota Orchestra and the Saint Paul Chamber Orchestra are prominent full-time professional musical ensembles who perform concerts and offer educational programs to the Twin Cities' community. The world-renowned Guthrie Theater moved into

Literature.

The rigors and rewards of pioneer life on the prairie are the subject of "Giants in the Earth" by Ole Rolvaag and the "Little House" series of children's books by Laura Ingalls Wilder. Small-town life is portrayed grimly by Sinclair Lewis in the novel "Main Street", and more gently and affectionately by Garrison Keillor

Entertainment.

Minnesota musicians include Holly Henry, Bob Dylan, Eddie Cochran, The Andrews Sisters, The Castaways, The Trashmen, Prince, Soul Asylum, David Ellefson, Chad Smith, John Wozniak, Hüsker Dü, Owl City, The Replacements, and Dessa. Minnesotans helped shape the history of music through popular American culture: the Andrews Sisters' "Boogie Woogie Bugle Boy" was an iconic tune of World War II, while the Trashmen's "Surfin' Bird" and Bob Dylan epitomize two sides of the 1960s. In the 1980s, influential hit radio groups and musicians included Prince, The Original 7ven, Jimmy Jam & Terry Lewis, The Jets, Lipps Inc., and Information Society.  Minnesotans have also made significant contributions to comedy,

Popular culture.

Stereotypical traits of Minnesotans include "Minnesota nice", Lutheranism, a strong sense of community and shared culture, and a distinctive brand of North Central American English sprinkled with Scandinavian expressions. Potlucks, usually with a variety of hotdishes, are popular small-town church activities. A small segment of the Scandinavian population attend a traditional lutefisk dinner to celebrate Christmas. Life in Minnesota has also been depicted or used as a backdrop, in movies such as "Fargo", "Grumpy Old Men", "Grumpier Old Men", "Juno", "Drop Dead Gorgeous", "Young Adult", "A Serious Man", "New in Town", "Rio", and in famous television series like "Little House on the Prairie", "The Mary Tyler Moore Show", "The Golden Girls", "Coach", "The Rocky and Bullwinkle Show", "How I Met Your Mother" and "Fargo". Major movies shot on location in Minnesota include "That Was

Health.

Minnesotans have low rates of premature death, infant mortality, cardiovascular disease, and occupational fatalities. They have long life expectancies, and high rates of health insurance and regular exercise. These and other measures have led two groups to rank Minnesota as the healthiest state in the nation; however, in one of these rankings, Minnesota descended from first to sixth in the nation between 2005 and 2009 because of low levels of public health funding and the prevalence of binge drinking. While overall health indicators are strong, Minnesota does have significant health disparities in minority populations.  On October 1, 2007, Minnesota became the 17th state to enact the Freedom to Breathe Act, a statewide smoking ban in restaurants and bars.  The Minnesota Department of Health is the primary state health

Education.

One of the Minnesota Legislature's first acts when it opened in 1858 was the creation of a normal school in Winona. Minnesota's commitment to education has contributed to a literate and well-educated populace. In 2009, according to the U.S. Census Bureau, Minnesota had the second-highest proportion of high school graduates, with 91.5% of people 25 and older holding a diploma, and the tenth-highest proportion of people with bachelor's degrees. In 2015, Minneapolis was named the nation's "Most Literate City", while St. Paul placed fourth, according to a major annual survey. In a 2013 study conducted

Transportation.

Transportation in Minnesota is overseen by the Minnesota Department of Transportation (MnDOT) at the state level and by regional and local governments at the local level. Principal transportation corridors radiate from the Twin Cities metropolitan area and along interstate corridors in Greater Minnesota. The major Interstate highways are Interstate 35 (I-35), I-90, and I-94, with I-35 and I-94 connecting the Minneapolis–St. Paul area, and I-90 traveling east-west along the southern edge of the state. In 2006, a constitutional amendment was passed that required sales and use taxes on motor vehicles to fund transportation, with at least 40 percent dedicated to public transit. There are nearly two dozen rail corridors in Minnesota, most of which go through Minneapolis–St. Paul or Duluth. There is water transportation along the Mississippi River system and from the ports of Lake Superior. Minnesota's principal airport is Minneapolis–St. Paul International Airport (MSP), a major passenger and freight

Law and government.

As with the federal government of the United States, power in Minnesota is divided into three branches: executive, legislative, and judicial.

Executive.

The executive branch is headed by the governor. Governor Tim Walz, DFL (Democratic–Farmer–Labor), took office on January 7, 2019. The governor

Legislature.

The Minnesota Legislature is a bicameral body consisting of the Senate and the House of Representatives. The state has 67 districts, each with about 60,000 people. Each district has one senator and two representatives, each senatorial district being divided into "A" and "B" sections for members of the House. Senators serve for four years and representatives for two years.  In the November 2010 Minnesota House election,

Judiciary.

Minnesota's court system has three levels. Most cases start in the district courts, which are courts of general jurisdiction. There are 279 district court judgeships in ten judicial districts. Appeals from the trial courts and challenges to certain governmental decisions are heard by the Minnesota Court of Appeals, consisting of 19

Regional.

In addition to the city and county levels of government found in the United States, Minnesota has other entities that provide governmental oversight and planning. Regional development commissions (RDCs) provide technical assistance

Federal.

Minnesota's United States senators are Democrat Amy Klobuchar and Democrat Tina Smith. The outcome of the 2008 U.S. Senate election in Minnesota was contested until June 30, 2009; when the Minnesota Supreme Court ruled in favor of Franken, Republican Norm Coleman conceded defeat. Franken resigned on January 2, 2018, and Minnesota Governor Mark Dayton appointed his lieutenant governor, Tina Smith, to Franken's seat until a special election

Tribal.

The State of Minnesota was created by the United States federal government in the traditional and cultural range of lands occupied by the Dakota and Anishinaabe peoples as well as other Native American groups. After many years of unequal treaties and forced resettlement by the state and federal government,

Politics.

Minnesota is known for a politically active citizenry, and populism has been a long-standing force among the state's political parties. Minnesota has a consistently high voter turnout. In the 2008 U.S. presidential election, 78.2% of eligible Minnesotans voted—the highest percentage of any U.S. state—versus the national average of 61.2%. Voters can register on election day at their polling places with evidence of residency.  Hubert Humphrey brought national attention to the state with his address at the 1948 Democratic National Convention. Minnesotans have consistently cast their Electoral College votes for Democratic presidential candidates since 1976, longer than any other state. Minnesota is the only state in the nation that did not vote for Ronald Reagan in either of his presidential runs. Minnesota has gone for the Democratic Party in every presidential election since 1960, with the exception of 1972, when it was carried by Republican Richard Nixon.  Both the Democratic and Republican parties have major-party status in Minnesota, but its state-level Democratic party has a different name, officially known as the Minnesota Democratic-Farmer-Labor Party (DFL). It was formed out of a 1944 alliance of the Minnesota Democratic and Farmer-Labor parties.  The state has had active third-party movements. The Reform Party, now the Independence Party, was able to elect former mayor of Brooklyn Park and professional wrestler Jesse Ventura to the governorship in 1998.

Media.

The Twin Cities area is the fifteenth-largest media market in the United States, as ranked by Nielsen Media Research. The state's other top markets are Fargo–Moorhead (118th nationally), Duluth–Superior (137th), Rochester–Mason City–Austin (152nd), and Mankato (200th).  Broadcast television in Minnesota and the Upper Midwest started on April 27, 1948, when KSTP-TV began broadcasting. Hubbard Broadcasting, which owns KSTP, is now the only locally owned television company in Minnesota. Twin Cities CBS station WCCO-TV and FOX station KMSP-TV are owned-and-operated by their respective networks. There are 39 analog broadcast stations and 23 digital channels broadcast over Minnesota. The four largest daily newspapers are the "Star Tribune" in Minneapolis, the

Sports, recreation and tourism.

Minnesota has an active program of organized amateur and professional sports. Tourism has become an important industry, especially in the Lake region. In the North Country, what had been an industrial area focused on mining and timber has largely been transformed into a vacation destination. Popular interest in the environment and environmentalism, added to traditional interests in hunting and fishing, has attracted a large urban audience within driving range.

Organized sports.

Minnesota has professional men's teams in all major sports.  The Minnesota Vikings have played in the National Football League since their admission as an expansion franchise in 1961. They played in Metropolitan Stadium from 1961 through 1981 and in the Hubert H. Humphrey Metrodome from 1982 until its demolition after the 2013 season for the construction of the team's new home, U.S. Bank Stadium. The Vikings' current stadium hosted Super Bowl LII in February, 2018. Super Bowl XXVI was played in the Metrodome in 1992. The Vikings have advanced to the Super Bowl Super Bowl IV, Super Bowl VIII, Super Bowl IX, and Super Bowl XI, losing all four games to their AFC/AFL opponent  The Minnesota Twins have played in the Major League Baseball in the Twin Cities since 1961. The Twins began play as the original Washington Senators, a founding member of the American League in 1901, relocating to Minnesota in 1961. The Twins won the 1987 and 1991 World Series in seven game matches where the home team was victorious in all games. The Twins also advanced to the 1965 World Series, where they lost to the Los Angeles Dodgers in seven games. The team has played at Target Field since 2010.  The Minneapolis Lakers of the National Basketball Association played in the Minneapolis Auditorium from 1947 to 1960, after which they relocated to Los Angeles. The Minnesota Timberwolves joined the NBA in 1989, and have played in Target Center since 1990.  The National Hockey League's Minnesota Wild play in St. Paul's Xcel Energy Center, and reached 300 consecutive sold-out games on January 16, 2008. Previously, the Minnesota North Stars competed in NHL from 1967 to 1993, which played in and lost the 1981 and 1991 Stanley Cup Finals.  Minnesota United FC joined Major League Soccer

Tourism.

As the state's tourism promotion office, Explore Minnesota pursues an entrepreneurial approach, leveraging the state's tourism investment with increased involvement by the private sector. A council of representatives from the state's tourism industry strongly connects Explore Minnesota with tourism businesses and organizations. Explore Minnesota's mission is to inspire and facilitate travel to and within the state of Minnesota.  Tourism is a $15.3 billion industry in Minnesota, and a key sector of the state's economy. The leisure and hospitality industry—a major provider of tourism services—employs more than 270,000 workers, representing 11 percent of Minnesota's private sector employment. Leisure and hospitality also generates 18 percent of the state's sales tax revenues. Minnesota welcomes more than 73 million domestic and international travelers annually.  In 2014, Explore Minnesota launched an all-new travel marketing campaign, themed "Only in Minnesota", to increase awareness about Minnesota as a one-of-a-kind Midwest travel destination.

Outdoor recreation.

Minnesotans participate in high levels of physical activity, and many of these activities are outdoors. The strong interest of Minnesotans in environmentalism has been attributed to the popularity of these pursuits.  In the warmer months, these activities often involve water. Weekend and longer trips to family cabins on Minnesota's numerous lakes are a way of life for many residents. Activities include water sports such as water skiing, which originated in the state, boating, canoeing, and fishing. More than 36 percent of Minnesotans fish, second only

Minnesota () is a state in the Upper Midwest, Great Lakes, and northern regions of the United States. Minnesota was admitted as the 32nd U.S. state on May 11, 1858, created from the eastern half of the Minnesota Territory. The state has many lakes, and is known as the "Land of 10,000 Lakes". Its official motto is (French for "The Star of the North").

Le Minnesota ( ) est un État du Midwest des États-Unis, bordé à l’ouest par le Dakota du Nord et le Dakota du Sud, au nord par les provinces canadiennes du Manitoba et de l'Ontario, à l’est par le lac Supérieur et le Wisconsin et au sud par l’Iowa.