Aarushhh/wikipedia-simple-splitted huggingface dataset:
A Taylor series is an  idea used in computer science, calculus, chemistry, physics and other kinds of higher-level mathematics. It is a series that is used to create an estimate (guess) of what a function looks like. There is also a special kind of Taylor series called a Maclaurin series.

The theory behind the Taylor series is that if a point is chosen on the coordinate plane (x- and y-axes), then it is possible to guess what a function will look like in the area around that point. This is done by taking the derivatives of the function and adding them all together. The idea is that it is possible to add the infinite number of derivatives and come up with a single finite sum.

In mathematics, a Taylor series shows a function as the sum of an infinite series. The sum's terms are taken from the function's derivatives. Taylor series come from Taylor's theorem.
History 
The Ancient Greek philosopher Zeno of Elea first came up with the idea of this series. The paradox called "Zeno's paradox" is the result. He believed that it would be impossible to add an infinite number of values and get a single finite value as a result.

Another Greek philosopher, Aristotle, came up with an answer to the philosophical question. It was Archimedes, however, who came up with a mathematical solution using his method of exhaustion. He was able to prove that when something is split up into an infinite number of tiny pieces, they will still add up to a single whole when all of them are added back together. The ancient Chinese mathematician Liu Hui proved the same thing several hundred years later.
The earliest known examples of the Taylor series are the work of Mādhava of Sañgamāgrama in India in the 1300s. Later Indian mathematicians wrote about his work with the trigonometric functions of sine, cosine, tangent, and arctangent. None of Mādhava's writings or records still exists today. Other mathematicians based their work on Mādhava's discoveries and worked more with these series until the 1500s.

James Gregory, a Scottish mathematician, worked in this area in the 1600s. Gregory studied the Taylor series and published several Maclaurin series. In 1715, Brook Taylor discovered a general method for applying the series to all functions. (All of the previous research showed how to apply the method to only specific functions.) Colin Maclaurin published a special case of the Taylor series in the 1700s. This series, which is based around zero, is called the Maclaurin series.
Definition 
A Taylor series can be used to describe any function ƒ(x) that is a smooth function (or, in mathematical terms, "infinitely differentiable.") The function ƒ can be either real or complex. The Taylor series is then used to describe what the function looks like in the neighborhood of some number a.

This Taylor series, written as a power series, looks like:

This formula can also be written in sigma notation as:

Here n! is the factorial of n. ƒ (n)(a) is the nth derivative of ƒ at the point a.  is a number in the function's domain. If the Taylor Series of a function is equal to that function, the function is called an "analytic function."

Maclaurin series 
When , the function is called a Maclaurin series. The Maclaurin series written as a power series looks like:

When written in sigma notation, the Maclaurin series is:

Common Taylor series 

Some important Taylor series and Maclaurin series are the following.

Where  is the nth Bernoulli number, and  is the natural logarithm.

References
References 

Calculus
Sequences and series
Wilhelm Furtwängler (born Berlin, 25 January 1886; died Baden-Baden, 30 November 1954) was a German conductor. He is thought of as one of the greatest conductors in history. Many people say that he is the best ever. The famous Italian conductor Arturo Toscanini said he was the world's best conductor other than himself.

Furtwängler was especially famous for conducting the music of famous German composers. His performances of Beethoven, Brahms, Bruckner, and Wagner are very well known and loved by many people.

Early life 
Furtwängler was born on January, 25, 1886 in Berlin, Germany. He grew up in Munich, where his father was an archaeologist and professor. He started learning about music when he was very young. He learned to play the piano and was very talented. He also began writing music. He wrote several pieces before he was 20 years old. He kept writing music for the rest of his life, but his pieces never became very famous.
Conducting career
Furtwängler first started conducting as a young man.  He wanted to conduct in order to perform his own music. However, he quickly became famous for conducting the music of others. The very first piece he conducted in public was the 9th Symphony of Bruckner. He conducted many orchestras before he finally became the leader of the world-famous Berlin Philharmonic Orchestra in 1922. Later, he also had many other important conducting jobs. The most important was the director of the Bayreuth Festival, a very famous German music festival.
The Nazis and World War II
When the Nazis took over Germany in the 1930s, Furtwängler was in an awkward position. He wanted to conduct some kinds of music that the Nazis did not like. He left some of his conducting jobs in protest when they did not let him perform. In 1936 he almost left Germany to live in the United States, where the New York Philharmonic Orchestra wanted him to conduct. However, the Nazis still thought he was a good conductor, and they kept him in Germany. He also wanted to stay to protect the German music from the Nazis. People in the United States did not like him for staying, even though he did not really like the Nazis.

During World War II Furtwängler continued to conduct the Berlin Philharmonic. He gave many very famous concerts during this time. But towards the end of the war, the Nazis became unhappy with him. He fled from Germany in 1945 and lived in Switzerland for several years. He did not conduct again for two years.
After the war
After the war, Furtwängler was still in a difficult position. The Allies thought that he had been a Nazi supporter because he had stayed in Germany. They put him on trial, but finally decided he was innocent. He was allowed to go back to conducting in 1947. Even though he was innocent, people in the US still did not like him. He was going to conduct the Chicago Symphony Orchestra, but he was not allowed to because people got angry about it.

Furtwängler gave many successful concerts after the war. He still conducted the Berlin Philharmonic and other famous orchestras in Europe. Furtwängler gave the most famous concert of his career in 1951. That year, he conducted Beethoven's 9th Symphony at the Bayreuth Festival. It was the first time that the festival had happened since the end of the war, six years before. Many people say that this concert was the greatest musical concert in history. Furtwängler finally died in 1954, when he was 68 years old.
Musical style
Furtwängler had a very unusual way of conducting. His movements with the baton were very awkward and jerky. Some people said he looked "like a puppet on a string" when he conducted. He liked to slow down and speed up the music very often. Furtwängler believed that there was more to music than just the notes on the score. He felt it was the performer's job to make each performance something special. This meant that he often played the same piece in very different ways at different concerts. Even when he changed the way he played a piece, though, the music was thought to be very beautiful. He did not like conductors who just played the notes on the page without doing anything special with the music.

As a younger conductor, Furtwängler played music by many different composers. However, as he got older, he usually only played music by the great German composers. Some of his favorites were Beethoven, Brahms, Bruckner, and Wagner.
Recordings 
Furtwängler did not make many recordings in studios. Recording technology was still very new at the time and did not work well for recording long classical pieces at first. However, many of Furtwängler's concerts were recorded, especially during and after World War II. Today people think these are some of the best recordings of all time. His famous concert at Bayreuth in 1951 is one of these concert recordings.

Other websites 
 Wilhelm Furtwängler Society of France
 Video of Furtwängler conducting the end of Beethoven's Ninth Symphony in 1942

1886 births
1954 deaths
German conductors
Musicians from Berlin
Musicians from Munich
Order of Merit of the Federal Republic of Germany
In professional wrestling, a face is a good guy. 

A face should not cheat and most will not use weapons. They often try to make the crowd happy and excited. 

Often, a face will fight a heel (bad guy), so the crowd will cheer the face and boo the heel.

Professional wrestling

de:Liste von Wrestling-Begriffen#F
The family Fagaceae, also called beech family, is a family of flowering plants. It has about 900 species of evergreen and deciduous trees and shrubs. They have alternate simple leaves with pinnate venation, unisexual flowers in the form of catkins, and fruit in the form of nuts. 

All the oaks, beeches and chestnuts are in this family.

Fagales
Plant families
A heat sink is an object that cools another part that is too hot. It works with a CPU fan to do this. The heat sink is in contact with the part that should be cooled. It takes heat away and dissipates it, for example into the air around it.

Heat sinks are found in most computers. The chips inside a computer can get very hot. Therefore, they need to be cooled, so that they don't break. This is usually done with a heat sink. Heat sinks are also found in most high fidelity audio amplifiers.

Computer hardware

pt:Dissipador
The haka (; plural haka, in both Māori and English) is a ritual dance of the Maori, the native people of New Zealand. Sometimes, a haka is performed to excite friends and to scare enemies. In peace time, a haka is performed as a challenge. 

A haka can include:
voice (chanting)
feet (stamping and leaping)
hand (slapping, waving and clapping)
eyes (rolling)
tongue (poking out)

There are many different haka. Each tells a story. The most famous haka is Ka Mate. The Ka Mate haka is performed by many New Zealand sports teams before games. Another famous haka is 'Kapo O Pango' which is performed by New Zealand's rugby union team. This team is called the All Blacks. 

Women are not usually allowed to perform haka. Instead, they sing and chant in support.

References

New Zealand culture
Crisis on Infinite Earths was a story told in American comic books in the year 1985. It lasted for 12 issues. Marv Wolfman wrote it and George Pérez drew it. It changed much about the history of the DC Universe, and allowed the editors of DC Comics to simplify  their then 55 year old history.

American comic books
American magazines
DC Comics
Magazines published in New York City
Endosymbiosis occurs when a symbiont lives inside the body or the cells of another organism. It is a very widespread phenomenon in living things.

Examples are:
Rhizobia: nitrogen-fixing bacteria which live in root nodules on plants of the pea family.
Singly-celled forams which include a single-celled alga inside the cell. This is 'facultative', which means they may or may not do it. A more far-reaching version is idioplastic endosymbiosis. Here, the foram consumes the alga, but keeps its chloroplasts in working order.
Green algae inside marine polychaete worms.
Single-celled algae inside reef-building corals.
Gut flora (often flagellates) inside the digestive systems of insects and vertebrates which digest plant cellulose. These are 'obligate' symbionts, which means the host must have them.
Lichen: fungus+alga or bacterium.
Mycorrhiza: fungal hyphae and roots of trees.
Eukaryote theory 
Endosymbiont theory is the idea that eukaryote cells arose in evolution by the fusion of previously free-living protists (prokaryotes).p143 The theory was first suggested by the Russian botanist Konstantin Mereshkovsky in 1905. The  nature of lichens had been worked out; mitochondria and chloroplasts had been seen in cells, and their similarity to bacteria noted. The theory was initially dismissed, but was re-examined when more was known about cell biology, by Lynn Margulis
The eukaryote cell is the type of cell all animals and plants are made of. Some cell organelles, such as mitochondria and chloroplasts, contain DNA. In each case, this DNA is thought to be the remnant of the  genome of a once independent bacterium. The theory is that the eukaryote cell evolved by the fusion of several bacteria or archaean organisms. Together, the new cells survived, prospered and evolved into new and complex forms of life. The origin of other organelles in the eukaryotic cell is still under review: the cell nucleus, its membrane, chromosomes and centromeres; the Golgi body; the flagella or cilia; the intracellular membranes. Some of these may also have had a symbiotic origin. 

Examples:
Mitochondria live inside the cells of all animals, plants, and fungi. They make a fuel for the cells called ATP; it is the most common fuel in the body. Mitochondria were once bacteria, but now they cannot live outside animal cells.
Choroplasts are plastids which live inside the cells of photosynthetic organisms. They contain chlorophyll, which grabs energy from sunlight and makes it into sugar. Chloroplasts were once cyanobacteria. Glaucophytes are an algae with chloroplasts that are more like blue-green bacteria: the cell walls are still sensitive to antibiotics.

Kelp and other brown algae are different from other endosymbiotic associations.  A brown algae cell fused with the cell of a green algae, which already had an endosymbiont.  This is called secondary endosymbiosis.

The endosymbiont for some dinoflagellates was once a brown algae. This is called tertiary (third) endosymbiosis.

Endosymbiosis in prokaryotes 
There is evidence that symbiosis happened between ancient bacteria to produce the double-membrane class known as gram-negative bacteria. Since the gram-negative bacteria include the cyanobacteria, this was the first of several such events in the history of the eukaryotes.

References
References 

Evolutionary biology
Cell biology
Microbiology
The four-stroke engine is an internal combustion engine. The four strokes are:

Related pages
 Two-stroke engine

Motors
The pecan (Carya illinoinensis) is a species of hickory nut, native to south-central North America, in the United States from southern Iowa, Illinois and Indiana east to western Kentucky, North Carolina and western Tennessee, south through Georgia, Alabama, Mississippi, Louisiana, Texas, Oklahoma and Arkansas; and in Mexico from Coahuila south to Jalisco and Veracruz.

"Pecan" is from an Algonquian word, meaning a nut requiring a stone to crack.

Pecans are often used in cooking in the Southern United States. A common dessert there is pecan pie.

References

Fagales
Edible nuts and seeds
Plants of North America
A tariff is a tax charged on goods as they pass between one country and another. A tariff can be placed on goods being brought into the country (imports), and goods being exported from the country to another. It is usually done to make money for the government. It may also be done for protectionism. Protectionism makes it easier for local products to sell by making products from foreign countries more expensive.

Often, one government will have an agreement with another not to place any tariffs on goods that are traded between them. This kind of agreement is called free trade.

Related pages 
 Customs
 Indirect tax
 International trade

References 
 

Taxation
In 1809, when Metternich became foreign minister, Napoleon had control of most of Europe. France had taken over some of the closest countries directly. In more distant countries like Austria and Prussia, Napoleon forced them to sign treaties that would make them fight on his side in wars. Metternich thought that was bad for Austria. When Napoleon declared war and raised a huge army for the French invasion of Russia, Metternich told the Russians that Austria would not attack but only defend. Napoleon lost badly in Russia, and Metternich used that excuse to get out of the treaty.

In 1814, troops of the Quadruple Alliance (Prussia, Russia, Austria and the United Kingdom) had entered France, and Napoleon had lost the war. For the next year, diplomats from all over Europe met at the Congress of Vienna to decide the future after Napoleon.
Metternich believed that the best way to keep Europe peaceful was to create a balance of power, with no country being strong enough to beat all the other countries. To make sure that happened, he made some countries stronger so that other countries, especially France, would think twice about going to war. For example, he added Belgium and Luxembourg to the 
Netherlands, he turned 300 small countries of Germany into a group of larger countries, and he put together some countries in what we call Italy today.
Metternich kept peace in Europe for a long time, but there were still some revolts in Europe. Finally in 1848, many revolts happened at the same time. One of them was in Austria, and the rebels had Metternich taken out of office. After he was gone, Otto von Bismarck in Prussia managed to become powerful, take over the German Confederation and start a big German country, which still exists. Having one big Germany, however, upset Metternich's balance and helped to cause World War I.

Other websites 

1773 births
1859 deaths
Ambassadors of Austria
Government ministers of Austria
People from Koblenz
Politicians from Rhineland-Palatinate
The German Confederation replaced the Holy Roman Empire in Central Europe. After the Holy Roman Empire fell, Germany had fallen into over 300 different small kingdoms. In 1815, the Congress of Vienna decided that these weak kingdoms were not strong enough to keep France from trying to take them over, which it had already done once under Napoleon. So the Congress combined all those little countries into 39 larger countries, which were still very small compared to the powerful countries of Europe. 

The problem was that the Congress did not want to make them too strong, or they'd start taking over other countries. So they put the 39 countries into a confederation which meant that they were all separate countries, but they agreed to help defend each other, and in some ways acted like one big country. The Confederation would not be strong enough to attack another country; only strong enough to preserve the European balance of power.
The German Confederation lasted until 1866, when the members fought each other. The winners formed a new North German Confederation. In 1871 after winning the Franco-Prussian War, Otto von Bismarck, chancellor of Prussia, combined all the countries of Germany into the German Empire.

19th century in Austria
19th century in Germany
Former states in Germany
1815 establishments in Europe
1866 disestablishments
1860s disestablishments in Europe
Former federations
WrestleMania XXIV is the twenty-sixth yearly WrestleMania professional wrestling pay-per-view event put on by World Wrestling Entertainment (WWE). It took place on March 28th, 2010 at the University of Phoenix Stadium in Glendale, Arizona.

Matches
Matches

Production
Global Spectrum, University of Phoenix Stadium's operator, had worked in past years with World Wrestling Entertainment (WWE) to get the event to its venue. On January 18, 2008, Global Spectrum publicly announced that it wants to hold WrestleMania in 2010. The event became more widely known weeks prior when a photo of Wayne Gretzky wearing a shirt showing the event was seen in the Swedish newspaper Expressen. A press conference happened on February 24, 2009 at the University of Phoenix Stadium to officially tell people about the event for Glendale, Arizona at the University of Phoenix Stadium; this event is the first time WrestleMania would happen in the state of Arizona. Tickets for the event went on sale November 7, 2009 at 10:00am MST. Advertisements telling people about the date tickets would go on sale used the song "Welcome to the World" by Kevin Rudolf.
Along with WrestleMania XXVI, a group of events known as "WrestleMania Week" was held in the week before the event. The third yearly WrestleManiArt, an art show and auction featuring work by WWE superstars, was held on March 24. WrestleMania's yearly fan convention, WrestleMania Axxess, was held from March 25 through to March 27. On March 27, WWE hosted its yearly WWE Hall of Fame ceremony at the Dodge Theater, where the 2010 members were made an official member of the hall of fame.

Related pages
 List of WWE pay-per-view events

References

Other websites
 The Official Website of WrestleMania

WrestleMania 26
2010 in professional wrestling
Glendale, Arizona
Sports in Arizona
2010s in Arizona
March events
Ice pellets are known as sleet in North America, and hail in Great Britain. They are a type of frozen precipitation, little balls of ice. Large ice pellets are called hailstones.  Sometimes, ice pellets bounce when they hit the ground.

References

Precipitation
A howitzer is a special type of big gun used by an army. It has a short barrel, and is used to fire a shell over a short distance. The barrel length of a howitzer is 15 to 25 times of the caliber. Howitzers are special because they're made to fire higher than a cannon but lower than a mortar. Howitzers are almost always used to shoot at targets on the ground, but they can be used for targets on water, or in the air. The name howitzer comes from an old Czech word, haufnice, which was a catapult that could fire many stones. The sinking of the USS Maine was most responsible for causing the Spanish-American War. On February 15th, 1898, the USS Maine exploded in Havana Harbor and sank, killing over 260 of those stationed to the boat.

Related pages
List of howitzers

References
John Updike (March 18, 1932 - January 27, 2009) was an American author of works including Rabbit, Run and Couples. He was born in Reading, Pennsylvania. He died of lung cancer in Danvers, Massachusetts in January 2009.

1932 births
2009 deaths
American Christians
American novelists
American poets
Cancer deaths in Massachusetts
Deaths from lung cancer
Writers from Pennsylvania
O. Henry Award winners
A clog is a kind of shoe. There are different kinds of clogs. They can be shoes, sandals or completely made out of wood.

Footwear
Dendrites are the branches of neurons that receive signals from other neurons. The signals go into the cell body (or soma).

A cell may have hundreds of dendrites, but may have only one axon. The dendrites carry signals from other neurons into the soma, and the axon carries a single signal from the soma to the next neuron or to a muscle fiber.

A dendrite from one neuron and an axon from another neuron meet at a synapse, which is a very narrow gap between the two cells. When electrical impulses reach the end of an axon, they trigger the release of chemicals called neurotransmitters. These chemicals cross the synapse to the dendrite, where they trigger the flow of ions into or out of the cell.

The movement of the charged ions in the dendrite causes an electrical current, which spreads to the soma briefly before being restored to normal.
If the dendrites get lots of signals from axons, then it sets off a chain reaction. The chain reaction is a strong electrical current called an action potential that flows down the axon to the next synapse.

Fully differentiated neurons do not divide. However, stem cells in the adult brain may regenerate functional neurons throughout the life of an organism. Generally, once born, neurons do not divide. Many will live the whole lifetime of the animal.

References 

Anatomy of the nervous system
The Sons of Eilaboun is a documentary movie by the Palestinian artist and movie maker Hisham Zreiq (Zrake). It was released in 2007. It tells the story of one of the massacres committed by the newly formed Israeli army during Operation Hiram. The massacres were committed in Eilaboun, a village in the northern Galilee between Nazareth and the Sea of Galilee. In the Eilabun massacre, fourteen men were killed, and twelve of them were executed. The village people were expelled to Lebanon and became refugees for a few months. The villagers eventually managed to return secretly.

Synopsis 

The movie starts with Melia Zreiq (an old woman from Eilaboun) saying

“I hope God will bring peace to this land, and let the peoples live together - a good life. I hope there will be peace.”
Ilan pappe takes about Plan Dalet, a plan that David Ben-Gurion and the Haganah leaders in Palestine worked out during autumn 1947 to spring 1948, and explains the details of the plan, and how was it performed. In October 30th, 1948, the Israeli army entered Eilaboun at approximately 5 AM. They then forced the people of Eilaboun together in the main square of the village. They chose seventeen young men. Five of them were taken as human shield, and the rest of the twelve were killed, each in a different location. This all happened after the expulsion of the rest of the village to Lebanon, where they became refugees after a five days forced march to Lebanon. After a UN peace keeper observed and reported Israel was forced to allow the people back.

That same night, the Israeli army entered Eilaboun, a then Christian village in the northern Galilee between Nazareth and the sea of Galilee. Most of the villagers were hiding in the two village churches.
About 52 villagers were left in the village, mainly old people and children. The priests complained about the expulsion of the villagers and demanded their return. Following a UN investigation and pressure activated by the Vatican, the villagers eventually managed to return clandestinely. After 6 months from the massacre most of the villagers managed to come back from Lebanon, and all the men were released from the prisoners of war camps.

Awards and festivals 
The movie won the Al-Awda award in 2008, and was screened in many festivals and events as:
 Sixth Annual International Al-Awda Convention 2008, USA
 Boston Palestine Film Festival 2008, USA
 Remembering the Nakba: 60 Years of Dispossession
 Regards Palestiniens, Montreal, Canada
 International İzmir Short Film Festival 2008, Izmir, Turkey
 Amal The International Euro-Arab film Festival 2008, Spain 
 Carthage Film Festival 2008 (Palestine: To remember section), Carthage, Tunisia
 Chicago Palestine Film Festival, 2009
References 
 Official website 
 
 When it all began (The long version of The sons of Eilaboun)

Documentaries
2000s historical movies
2007 movies
Arab–Israeli conflict
English-language movies
Multilingual movies
Red Hat, Inc. is an American software company. It makes open source software products. The company was founded in 1993. Red Hat has its headquarters in Raleigh, North Carolina, with other offices worldwide.

References

Other websites

 

 
 Red Hat contributions

 
Free software
American software companies
Companies based in North Carolina
1993 establishments in the United States
Raleigh, North Carolina
Mischief night is a tradition in some parts of the world; a night when people do mischief to their neighbours. This is usually 30 October, the day before Halloween night.
However in some parts of the North of England it is the night before Bonfire Night i.e.the 4th November.

Traditional practice

Traditional mischiefs:

Knocking and tapping on doors and windows
Throwing paint
Putting treacle on door handles
Tying door handles together to stop them opening
Moving gates
Egging houses
Toilet papering houses

Current Day Practice
Sometimes combined with Trick or Treat.

In Detroit and other parts of Michigan, October 30 is called Devil's Night and includes vandalism and arson.
In southern New Jersey and the Philadelphia region, October 30 is referred to as "Mischief Night," where mischievous teens soap car windows, egg houses, adorn trees with toilet paper, and run away after ringing doorbells. In other parts of New Jersey, October 30 is also known as "Cabbage Night" or "Goosey Night."  In Camden, New Jersey.  Over 130 arsons were committed in that city on the night of October 30, 1991.

It is known as "Gate Night" in Trail, British Columbia, Winnipeg, Canada and as Mat Night in Quebec, Canada, always on the 30 October, the eve of Halloween. It is also commonly known as "Devil's Night" in many places throughout Canada.

In Yorkshire, it is also known as "mischievous night", "Miggy Night", "Tick-Tack Night", "Corn Night", "Trick Night" and "Micky Night". In Liverpool, it is known as "Mizzy Night"(but unlike in Yorkshire, where it is celebrated on October 30th). It was celebrated on Nov 4 in Merseyside during the 1970s, as well as in Manchester after the war.
Mischief night is becoming popular in Ireland, where teenagers get the week around Halloween off school. This means that many of the nights before 31 October are used by teenagers for vandalism.

Modern mischief includes toilet papering gardens and buildings, flouring and egging of cars, people, and homes, "forking" gardens, setting off fireworks and smashing pumpkins and jack-o'-lanterns.  Local shops do not sell eggs to chavs around the time of Halloween.  Sometimes the damage includes spray-painting of buildings and homes.

People play "Ding-Dong Ditch": in this 'game', people knock on doors and then run and hide.

Media
A 2006 film Mischief Night is based on a night in Leeds, UK.

Notes

References
 Confessions from a Mischief Night brat  BBC Yorkshire report — November 2006
 Police Patrol for Mischief Night BBC Merseyside report — November 2006
 Dialect Survey Results  US terms;prevalence and distribution

British culture
Crime
Observances
Dengue fever (pronounced "DEN-gi") is a  tropical infectious disease caused by the dengue virus. People get the dengue virus from mosquitoes. Dengue fever is also called break-bone fever, because it can cause so much pain that people feel like their bones are breaking.

Most people with dengue fever can get better just by drinking enough water.  However, a small number of people get dengue hemorrhagic fever or dengue shock syndrome.  These are medical emergencies and can kill a person if they do not get medical treatment.

There is no vaccine that can keep people from getting the dengue virus.  There is also no treatment to cure dengue fever.  Doctors can only provide "supportive care," which means they can only treat dengue's symptoms.

Since the 1960s, many more people have been getting dengue fever.  Since World War II, dengue has become a problem around the world.  It is common in more than 110 countries. Every year, between 50 million and 100 million people get dengue fever.

Signs and symptoms
Signs and symptoms

Most people who get the dengue virus (80%) have no symptoms, or have only mild symptoms (like a basic fever).  About 5% of infected people (or 5 out of every 100) get much sicker.  A small number of these people have symptoms that could kill them.

After a person gets the dengue virus from a mosquito, it takes between 3 and 14 days for them to get sick.  (This is called the virus's incubation period.)  Most often, people start to feel sick after 4 to 7 days.

Often, when children have dengue fever, their symptoms are the same as gastroenteritis (stomach flu), like vomiting and diarrhea, or the common cold.  However, children are more likely to have bad complications from dengue fever.

Dengue fever happens in three stages: febrile, critical, and recovery.
The febrile stage 
In the febrile stage, people with dengue usually have a high fever.  ("Febrile" means that a person has a fever.) The fever is often over 40 degrees Celsius (104 degrees Fahrenheit).  Sometimes the fever gets better, and then comes back.

During the febrile stage, people may also have:
 Pain all over their bodies
 A headache
 A rash (this happens in 50% to 80% of people who get sick from dengue)
 Petechiae (small red spots on the skin).  These are caused by capillaries (which carry blood) breaking.  This makes the blood leak out and show up under the skin.
 Small amounts of bleeding from the mucous membranes in the mouth and nose
The febrile stage usually lasts 2 to 7 days.  This stage ends when a person's high fever is gone.

The critical stage 
In about 5% of people with dengue fever, the disease goes into a critical stage next.  ("Critical" means "very dangerous.")  The critical phase usually lasts 1 to 2 days.
During this stage, plasma (the liquid part of blood) leaks out of the body's small blood vessels.  The plasma can build up in the chest and abdomen.  This is a serious problem for a few reasons.

Plasma carries blood cells, glucose (sugar), electrolytes (salts), and many other important things to the whole body.  Every part of the body needs these things to survive.  If too much plasma leaks out of the blood vessels, there will not be enough left to carry these things to the body's most important organs.  Without these things, the organs cannot work normally.  This is called dengue shock syndrome.

Plasma also carries platelets, which help the blood clot (they help stop bleeding).  If a person does not have enough platelets, they can have dangerous bleeding.  With dengue fever, this bleeding usually happens in the gastrointestinal tract.  When a person has bleeding, leaking plasma, and not enough platelets, they have dengue hemorrhagic fever.  ("Hemorrhage" means "dangerous bleeding.")
The recovery stage 
The recovery stage is when the patient's body is overcoming the disease process. In this stage, the plasma that leaked out of the blood vessels is taken back up into the bloodstream.  This stage usually lasts 2 to 3 days.

During this stage, people with dengue often feel much better. However, they can have very bad itching and a slow heart rate.

Serious problems can also happen during the recovery stage.  If a person's body takes too much fluid back up into the bloodstream, this can cause "fluid overload."  This can cause fluid to build up in the lungs, which causes breathing problems.  Fluid overload can also cause seizures or an altered mental status (changes in a person's thinking and behavior).
Complications
Every once in a while, dengue can affect other systems in the body.  For example, dengue can cause:
 Altered mental status: This happens in 0.5% to 6% of people with very bad dengue fever.  It can happen when the dengue virus causes an infection in the brain.  It can also happen when important organs, like the liver, are not working correctly because of dengue.
 Neurological disorders: These are problems with the brain and the nerves, like Guillain–Barré syndrome  and Post-dengue acute disseminated encephalomyelitis.
 Infection of the heart, or sudden liver failure (these are very uncommon).

Cause
Cause

Dengue fever is caused by the dengue virus. In the scientific system that classifies viruses, the dengue virus is part of the family Flaviviridae and the genus Flavivirus.  Other viruses that belong to the same family and can make humans sick include yellow fever virus, West Nile virus, Zika virus, Japanese encephalitis virus, and tick-borne encephalitis virus.  Most of these viruses are spread by mosquitoes or ticks.

How dengue is spread

Dengue virus is spread mostly by mosquitoes from the Aedes genus, especially the Aedes aegypti species of mosquito.  Aides aegypti is the most likely type of mosquito to spread dengue, because it likes to live close to humans and feed off of people instead of animals.  A person can get the dengue virus from just one mosquito bite.
Sometimes, mosquitoes can also get dengue from humans.  If a female mosquito bites someone with dengue, the mosquito may get the dengue virus from the person's blood.  After about 8 to 10 days, the virus spreads to the mosquito's salivary glands, which make saliva (or "spit").  Now the mosquito will make saliva that is infected with the dengue virus.  When the mosquito bites a human, its infected saliva goes into the human and can give that person dengue.

A person can also get the dengue virus if they get a blood transfusion or organ donation from someone who has the virus.  In some countries where dengue is common, like Singapore, between 1.6 and 6 blood transfusions out of every 10,000 spread dengue.

The dengue virus can also be spread from a mother to her fetus during pregnancy, or when the child is born.  This is called vertical transmission.

Dengue is usually not spread in any other ways.
Dengue virus in the human body 
Once a person gets the dengue virus from a mosquito, the virus attaches to and enters the person's white blood cells.  (The white blood cells are part of the immune system, which defends the body by fighting off threats, like infections.)  As the white blood cells move around the body, the virus makes copies of itself.  The white blood cells react by making many special proteins, like interferon, which tell the immune system to work harder because there is a threat in the body.  These proteins cause the fever, flu-like symptoms, and severe pains that happen with dengue.

If a person has a bad infection, the virus makes copies of itself much more quickly inside the body.  Because there is a lot more of the virus, it can affect many more organs (like the liver and the bone marrow).  The virus can stop the bone marrow from making platelets normally.  This makes very bad bleeding much more likely to happen.
Risk factors
Babies and young children with dengue are more likely than adults to become very sick.  Women are more likely than men to get very sick.  Dengue can be life-threatening in people with chronic (long-lasting) diseases, like diabetes and asthma.

There are four different types of the dengue virus.  Once a person has had one type of the virus, he usually is protected from that type for the rest of his life.  However, he will only be protected against the other three types of the virus for a short time.  If he later gets one of those three types of the virus, he will be more likely to have serious problems, like dengue shock syndrome or dengue hemorrhagic fever.

Diagnosis
Usually, doctors diagnose dengue by examining the infected person and realizing that their symptoms match dengue.  However, when dengue is in its early stages, it can be difficult to tell the difference between this disease and other infections caused by viruses.
The World Health Organization says that a person probably has dengue if:
 He has a fever; AND
 He has two of these symptoms:
 Nausea and vomiting; 
 A rash; 
 Pain all over the body;
 A low number of white blood cells; or 
 A positive tourniquet test.  (To do this test, a doctor wraps a blood pressure cuff around a person's arm for five minutes, then counts any red spots on the skin.  If the person has many spots, they are more likely to have dengue fever.)
The World Health Organization also says that in areas where dengue is common, any warning signs, plus a fever, usually signal that a person has dengue fever.
Blood tests 
Some blood tests show changes when a person has dengue fever.  The earliest change is a low number of white blood cells in the blood.  A low number of platelets can also signal dengue.  Special blood tests can look for the dengue virus itself; the virus's nucleic acids; or the antibodies that the immune system makes to fight off the virus.  However, these special tests are expensive.  Also, in many areas where dengue is common, most doctors and clinics do not have laboratories for blood tests or special machines.
It can be difficult to tell the difference between dengue fever and chikungunya. Chikungunya is a similar viral infection that has many of the same symptoms of dengue, and happens in the same parts of the world.  Dengue can also have some of the same symptoms as other diseases, like malaria, leptospirosis, typhoid fever, and meningococcal disease. Often, before a person is diagnosed with dengue, their doctor will do tests to make sure they do not actually have one of these diseases instead.

WHO classification systems
In 1997, the World Health Organization (WHO) created a system for describing the different types of dengue fever.  Eventually, the WHO decided that this old way of dividing dengue needed to be simpler.  It also decided that not everyone with dengue fever fit into the old categories.

In 2009, the WHO changed its system for classifying (dividing) dengue fever.  However, the older system often is still used.
The old system 
The WHO's old system divided dengue into three categories:
 Undifferentiated fever
 Dengue fever
 Dengue hemorrhagic fever.  This was then divided into four stages, called grades I-IV:
 In Grade I, the person has a fever. He also bruises easily or has a positive tourniquet test.
 In Grade II, the person bleeds into the skin and other parts of the body.
	In Grade III, the person shows signs of circulatory shock.  This is called dengue shock syndrome. 
	In Grade IV, the person has shock so severe that his blood pressure and heartbeat cannot be felt.  This is a more serious version of dengue shock syndrome.

The new system 
In 2009, the WHO created a simpler system which divided dengue fever into two types: 
 Uncomplicated: People who just have the febrile stage of dengue fever, and never go into the critical phase.  They get better on their own or just need basic medical help.
 Severe: People who have symptoms that could kill them, or have serious complications from dengue.
Prevention
There are no vaccines that can keep people from getting the dengue virus.  The best ways to prevent dengue are to protect people from mosquito bites and to control the mosquito population.

The best way to control the mosquito is to get rid of its (the places it lives)  The best way to do this is to get rid of areas with standing water (water that does not move).  Mosquitoes like standing water and often lay its eggs, to prevent getting bitten by mosquitoes, people can: 
 Wear clothing that fully covers their skin
 Use bug spray 
 Use mosquito netting when they are resting.
Integrated Vector Control 
The WHO suggests a program for preventing dengue (called an "Integrated Vector Control" program) that includes five different parts: 
	Advocacy, people working together, and legislation (laws) should be used to make public health organizations and communities stronger.
	All parts of society should work together. This includes the public sector (like the government), the private sector (like businesses and corporations), and the health care field.
	All ways of controlling disease should be brought together.
	Decisions should be make based on evidence.  This will help make sure that the things that are done to address dengue are helpful.
	Areas where dengue is a problem should be given help, so that they can build their abilities to respond well to the disease on their own.
Treatment
There are no specific treatments for dengue fever.  No known anti-viral medications (medicines which kill viruses) will kill the dengue virus.  Health workers can give "supportive treatment" - treat dengue's symptoms to try to make patients feel better.
Different people need different treatments, depending on their symptoms. Some people can get better just by drinking fluids at home, and checking with their doctor to make sure they are getting better.

Treating dehydration is very important.  Sometimes, people are so dehydrated that they need intravenous fluids - fluids given through a needle placed into a vein.  Usually, people only need intravenous fluids for a day or two.

Doctors can give medicines like acetaminophen (paracetamol) for fever and pain.  Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and aspirin should not be used because they make bleeding more likely.
People with bad dengue may need blood transfusions.  Having extra blood will help a person if their blood pressure is getting very low (like it does in dengue shock syndrome) or if they do not have enough red blood cells in their blood (because they are bleeding from dengue hemorrhagic fever).

When people reach the recovery stage of dengue, doctors usually stop giving intravenous fluids to prevent fluid overload (having too much fluid in the body).  If a person gets fluid overload, doctors can give a type of medication called a diuretic, which will make the patient urinate out the extra fluid.

Prognosis 
Most people with dengue recover and don't have any problems afterward.

Without treatment, 1% to 5% of infected people (1 to 5 out of every 100) die from dengue.  With good treatment, less than 1% die.  However, 26% of people with severe dengue die.
Epidemiology
Dengue is common in more than 110 countries. Every year, it infects 50 to 100 million people around the world. It also causes half a million hospitalizations and about 12,500 to 25,000 deaths around the world each year.  However, the World Health Organization says that dengue fever is not taken as seriously as it should be.  It calls dengue one of 16 "neglected tropical diseases" - diseases which do not get enough attention.  In every million people, dengue causes about 1600 years of life to be lost.  This is about the same as other tropical and deadly diseases, like tuberculosis.  However, the WHO says the neglected tropical diseases, like dengue, do not get the attention and money that is needed to find treatments and cures.
Dengue is becoming much more common around the world.  It is the most common viral disease that is spread by arthropods.  In 2010, dengue was 30 times more common than it was in 1960.  Scientists think dengue may be getting more common because:
 More people are living in cities. 
 There are more people in the world.  The world's population is growing. 
 More people are travelling internationally (between countries). 
 Global warming is thought to play a part in the increase in dengue.
Dengue happens most around the equator. 2.5 billion people live in areas where dengue happens. 70% of these people live in Asia and the Pacific. In the United States, 2.9% to 8% of people who come back from traveling in areas where dengue happens, and have a fever, were infected while traveling.  In this group of people, dengue is the second most common infection to be diagnosed, after malaria.
History
Dengue fever is probably a very old disease.  An ancient Chinese medical encyclopedia from the Jin Dynasty (which existed from 265 to 420 AD) talked about a person who probably had dengue. The book talked about a "water poison" that had to do with flying insects.

Written records from the 17th century talk about what may have been epidemics of dengue (where the disease spread very quickly in a short time). The most likely early reports of dengue epidemics are from 1779 and 1780.  These reports talk about an epidemic that spread across Asia, Africa, and North America. From that time until 1940, there were not many more epidemics.

In 1906, scientists proved that people were getting infections from Aedes mosquitoes.  In 1907, scientists showed that a virus causes dengue. This was just the second disease that was shown to be caused by a virus. (The first was yellow fever.) John Burton Cleland and Joseph Franklin Siler kept studying the dengue virus, and figured out the basics of how the virus spreads.
Dengue began to spread much more quickly during and after World War II.  Different types of dengue also spread to new areas.  For the first time, people started to get dengue hemorrhagic fever.  The first case of dengue hemorrhagic fever happened in the Philippines in 1953. By the 1970s, dengue hemorrhagic fever had become a major cause of death in children.  It also spread to the Pacific and the Americas.  Dengue hemorrhagic fever and dengue shock syndrome were first reported in Central America and South America in 1981.
History of the word
It is not clear where the word "dengue" came from.  Some people think that it comes from the Swahili phrase Ka-dinga pepo.  This phrase talks about the disease being caused by an evil spirit.  The Swahili word dinga is thought to come from the Spanish word dengue, which means "careful." That word may have been used to describe a person having bone pain from dengue fever; that pain would make the person walk carefully. However, it is also possible that the Spanish word came from the Swahili word, and not the other way around.

Other people think that the name "dengue" comes from the West Indies. In the West Indies, slaves that had dengue were said to stand and walk like "a dandy." Because of this, the disease was also called "dandy fever."