open-index/open-wikipedia-markdown huggingface dataset:
Electric field

An **electric field** is a vector field that shows the direction that a positively charged particle will move when placed in the field. More precisely, if a particle has an electric charge q and is in an electric field \vec{E}, the electric force the charge will feel is \vec{F}=q\cdot \vec{E}. Electric fields are produced around objects that have electrical charge, or by a magnetic field that changes with time. Electric field lines are used to represent the influence of electric field.  The idea of an electric field was first made by Michael Faraday.

Electric fields are caused by electric charges, described by Gauss's law, or varying magnetic fields, described by Faraday's law of induction.  The equations of both fields are coupled and together form Maxwell's equations that describe both fields as a function of charges and currents.

## Related pages
**Polarization electric field* and *ambipolar electric field*

## References
Audiobook

.]]
**Audiobooks** or "talking books" are books that have been read aloud by someone and recorded. Nowadays, they are usually recorded onto compact discs (CDs), although some older editions remain on cassette tapes. (This is why many texts in this format were first called books-on-tape.) More recently, audiobooks have been available to download from the internet (free or paid-for) and pre-recorded on special MP3 players.

While audiobooks can be used by anyone, they serve as a main resource for people who are blind or cannot see well.

Many popular books are often chosen to be turned into audiobooks. The original author may or may not be involved in choosing the narrator for the reading. Some authors often use the same reader for many books, so that their audiobooks have a similar sound or style.

## References
Slovak Wikipedia

The **Slovak Wikipedia** (In Slovak: *Slovenská Wikipédia*) is the Slovak-language edition of Wikipedia. This edition began in October 2003.

It is the 44th largest edition of Wikipedia by number of articles.

 it has over 250,000 articles.

## References 
## Other websites 
* Slovak Wikipedia main page
Rule against perpetuities

The Rule against Perpetuities is one of the most complicated rules in property law and wills and trusts.  In general, the rule states that a gift of a will (or a trust) will not be enforced if the subject of the gift is to be given to a person who can not be known now, and will not be able to be known, by the end of 21 years after the death of everyone who was alive (including children in their mother's uterus but not yet born) at the time the gift was created.  

For example, if a woman says in her will that her house is to be given "to the children of her children when they graduate from college" this would not be enforced by a court. It would not be enforced because one (or more) of her children's children might not graduate from college until 21 years after everyone who was alive at the time of the woman's death has died.  

The purpose of the rule is to prevent property from being tied up for "perpetuity" (a very long time).  The courts (and many people in society) do not want to hold property to see who will receive it after a complicated set of rules from the gift-giver. First, this would result in a waste of the courts' time and resources. Second, it would be a waste of the property that is being given through the gift.  If a gift in a will violates the Rule against Perpetuities, the court will simply strike that gift and transfer the subject of the gift as if the will had not mentioned it.

However, many countries and states have changed this rule, and it does not apply at all, or in a changed way, in those countries and states.
Parsec

The **parsec** (symbol: **pc**) is a unit of distance used in astronomy. It is the distance that light travels in 3.26 years, or just under 31 trillion kilometres (about 19 trillion miles). 

This is from the definition: a parsec is the distance from the Sun to an object which has a parallax angle of one arcsecond. The technique used in the calculation is trigonometry. 

It takes 3.26 years for the light to come from a parsec away.

## Related pages 
*Astrometry
Puget Sound

**Puget Sound** is a sound in northwestern Washington State. It is a large area of salt water that is partially cut off from the rest of the Pacific Ocean. Many of Washington's cities, like Seattle and Tacoma are next to the sound. Many boats and ships travel on the sound. Some of the ships are ferries which take people and cars from the main part of Washington to the islands in the sound and to the Olympic Peninsula. Many ships come from across the ocean from places like Japan and China to trade in Washington.

## References
## Other websites
The Legacy of Heorot

***The Legacy of Heorot*** is a science fiction novel written in 1987 by Larry Niven, Jerry Pournelle and Steven Barnes.

This is the first book in the *Heorot* series. It is about a human space colony at the star Tau Ceti.

## Plot Summary 
Hundreds of years in the future, people travel to the star Tau Ceti. It takes 100 years to fly there. To live that long the people go to sleep and freeze each other. When they get there they unfreeze, but some people do not wake up. Some people wake up but are not as smart as they were.

They land on the fourth planet from the sun and build a town on a big island. Everything is peaceful until they are attacked by a large animal. The animal is like a cross between a frog and an alligator. It is big but also *very* fast and smart. They call it a Grendel. The Grendel kills several people but then it is killed.

The people get very scared and build fences, land mines, and guns. After a while they get less scared and think that the Grendel they killed was the only one. They build boats and get brave. Then another bigger Grendel kills some of the people in the boats. The People trap and kill this Grendel.

The People get really mad. They find out that Grendels have to stay near water because when a Grendel moves fast it makes a lot of heat. If it does not cool off it will die. They go all around the island and kill all the Grendels. This makes them very happy.

They feel safe and travel all around the island. They notice that the alien fish are big now. They think that without the Grendels around there will be lots of fish to eat. This makes them happy.

Everything is good until the fish get very big. When they get big enough they grow legs, breath air, and move very fast. The fish are *baby Grendels*. Now instead of a few big Grendels there are thousands of small ones.

Some people escape to the space ship. But, other stay to defend the town. They use the electric fences and land mines and guns to kill the little Grendels. After awhile the town gets too damaged to protect anymore. The people run away to a cave on a mountain. The Grendels follow them up a river and attack the cave. The people use kerosene to burn the Grendels. Also, they knock big rocks down onto them. After enough Grendels get killed, the other Grendels learn to run away instead of just attack. The people *win*.

Over time the people hunt down all the new Grendels and all the alien fish. Finally they are safe.
Northrop Grumman B-2 Spirit

The **Northrop Grumman B-2 Spirit** is an American strategic bomber. It is designed to get through many anti-aircraft defenses. It can drop both conventional and nuclear bombs. Up to 80 -class JDAM GPS-guided bombs, or sixteen  B83 nuclear bombs, can be dropped by such bombers.

## Overview
The bomber was designed as an "Advanced Technology Bomber" (ATB) under the Carter government. The development continued under the Reagan government. The bomber is made by Northrop Grumman. Each aircraft cost US$737&nbsp;million (in 1997 dollars).

## Operations
 B-2 Spirit over the Pacific Ocean in May 2006.]]

The B-2 bombers was first used against Serbia in the 1999 Kosovo War, later in the Iraq War. In 2023, it landed for the first time in Europe – leaving Norway after training with NATO forces.

### Operation Midnight Hammer
In the early morning of June 22, 2025, seven USAF B-2 bombers conducted the "Operation Midnight Hammer" to bomb Iran's Fordow and Natanz nuclear sites. and the largest B-2 bomber mission in history ‒ involving 125 aircraft when fighter jets and refueling planes are counted in. Trump said that the Iranian nuclear sites had been "completely and totally ".

## Issues
The bomber is reportedly expensive, sparking controversies in the U.S. Congress, which initially wanted 132 bombers, but reduced it to 21 in the 1990s. In 2008, a B-2 was destroyed in a crash shortly after takeoff. The crew got out safely. 20 B-2s are being used by the United States Air Force. 

## References
Lamar Advertising

**Lamar Advertising** is an outdoor advertising company. The company was founded in the year 1902. The company's headquarters is in Baton Rouge, Louisiana. Lamar operates in the United States of America, Canada and Puerto Rico. They sell advertising on billboards. They sell advertising on buses. They have digital billboards. 

## Departments 
Lamar has many parts called "departments". This is common in most companies. Here are some parts of Lamar.
* IT (it stands for Information Technology)
* Human Resources
* National Sales
* Plants (this is what Lamar calls its offices)

## Other websites 
* Lamar
Carl Pomerance

**Carl Pomerance** (born 1944, Joplin, Missouri) is a mathematician. Most of his work has been in number theory. He helped find the quadratic sieve which is a way to factor big numbers very fast. He teaches at Dartmouth College. He has Erdős number 1. 

## References
Carnegie Mellon University

**Carnegie Mellon University** is a research university. It is in Pittsburgh, Pennsylvania. It is known for research in computer science. It is ranked #1 in the United States for computer science.

## References
Puzzle Quest: Challenge of the Warlords

***Puzzle Quest: Challenge of the Warlords*** is an adventure puzzle video game made by Infinite Interactive and ed by D3 Publisher in 2007.
Josh Groban

**Joshua Winslow "Josh" Groban** (born February 27, 1981) is an American singer, songwriter, musician, actor, and record producer. He has won many Tony and Grammy awards throughout his career, including one for Natasha, Pierre and the great Comet of 1812. He is playing Sweeney Todd now.

## Early life and education 
Groban was born in Los Angeles, California, to Jack Groban, a businessman, and Lindy Groban (née Johnston), a school teacher. His father is a descendant of Jewish immigrants from Poland and Ukraine, but converted from Judaism to Christianity upon marrying his mother. His mother's ancestry includes English, German, and Norwegian; one of her own grandfathers had also been Jewish. At this time, he was more focused on acting, playing Tevye in his high school's production of *Fiddler on the Roof*. In the summers of 1997 and 1998, he also attended the Interlochen Center for the Arts Camp in Michigan, majoring in musical theater, and began taking vocal lessons. He went on to attend the Los Angeles County High School for the Arts as a theater major and graduated in 1999. He was admitted to and briefly attended Carnegie Mellon University, intent on studying musical theater. Four months into his first semester, Groban was offered a recording contract and left college to pursue a singing career.
He is playing Sweeney Todd, and he claims to be a pescetarian... because of meat pies

## References
Xkcd

***xkcd*** is a comic strip on the Internet. American cartoonist Randall Munroe draws and writes the comic. The comic is drawn in boxes. It is one of the most popular comics on the Internet. It is "a webcomic of romance, sarcasm, math and language". Sometimes, the readers of the comic act out things that Munroe puts in his comics. There are also messages in all comics that show up when . In October 2007, the comic was viewed about 60 million times. The comic has won many awards. The name "xkcd" does not mean anything and was just made so people do not say it as a word. , there are over 3000 different *xkcd* comics.

In November 2015, Munroe wrote a book named *Thing Explainer*,  using the same stick figure drawings from his comic. The book is about how things work, and is written in Simple English. It uses only one thousand different simple words. The idea for it came from a comic "Up goer Five" which is about the Saturn V rocket.

## References 
**Notes**

## Other websites 
* Main site
* A site for explaining the comics of xkcd
Slip End

**Slip End** is a medium sized village in South Bedfordshire, England. There is one school in the village - Slip End Lower School serving the community and surrounding areas from Reception to Year 4 Children.

There are two community venues in the village:

*The Village Hall is at the centre of the village.
*Peter Edwards Hall and playing fields is adjacent to the Church, St Andrews, next to the M1 motorway.

## Other websites 
*Slip End official website
Alex Fraser

**Alex Fraser** can be any of the following:

*Alex Fraser (scientist), Australian scientist
*Alex Fraser (politician), Canadian politician
*Alex Fraser Bridge
Great Northern War

The **Great Northern War** (1700–1721), was a war fought between Sweden and the coalition of Russia, Saxony, Poland, and Denmark-Norway. In 1715 Prussia and Hannover joined the war against Sweden. The King of Hannover was also King George II of Great Britain.

After the coalition attacked them, Sweden invaded Russia in 1709 which was not a good idea. The Russian Army retreated  so the Swedish Army had to chase them. When winter came it was the coldest winter that Europe had had in a hundred years and half of the Swedish soldiers died in the cold. Eventually the Swedish army caught up to the Russian army and they had a battle, called the battle of Poltava. Russia won the battle but most of the Swedish soldiers, including king Charles XII of Sweden, escaped and went to the Ottoman Empire. Peter, the king of Russia, didn't like this so he declared war on the Ottoman Empire.  He lost and had to give the town of Azov back to the Ottomans.

Charles XII left the Ottoman Empire in 1714 and went to Stralsund in Pomerania which was owned by Sweden at the time but was under siege.  Charles escaped back to Sweden just before the people in Stralsund surrendered. Then he invaded Norway (which was owned by Denmark at the time.) and was shot and killed there. With their king gone, the Swedish soldiers left Norway and went back to Sweden. On the way back many soldiers died.

When all that was happening Russia had been invading Sweden. Russia conquered  Estonia, Livonia and Ingria. By the time the remaining soldiers had come back from Norway, Russia had completely conquered Finland. Sweden still didn't want peace though, because they would have to give lots of land to Russia. Russia used a newly made fleet of ships to attack and raid the Swedish Coast and Sweden would still not give up.  Eventually the Russian and Swedish ships came together in the Battle of Grengam. Both sides thought they had won the battle so no treaty was signed until the Russians continued using their boats to damage the Swedish coast. Finally Sweden gave up in 1721. Sweden had made peace with Denmark in 1720 and in 1721 Sweden signed the treaty of Nystad.

## Treaties 
In the Treaty of Nystad, or Treaty of Uusikaupunki, Sweden had to give land to other countries. Sweden had to give Estonia, Livonia and Ingria to Russia but kept Finland. Sweden also signed other treaties. In the treaty of Stockholm, Sweden gave Prussia Swedish Pomerania. In the treaty of Fredericksborg where Sweden had to pay Denmark-Norway money for the damage the war had done.

This war allowed Russia to become the dominant power in Northeastern Europe, instead of Sweden.
CentOS

**CentOS** is a distribution (or *distro*) of Linux that is made to be similar to Red Hat Enterprise Linux (RHEL). It was made as a free alternative that is compatible with RHEL. Now, many people work on CentOS, and many more people use it on their computers. Often, CentOS is used on servers (computers which provide services to people or other computers) because it is stable (does not break often) and can be installed (put on a computer) in not much time, compared to other distributions such as Gentoo. 

In January 2014, CentOS, officially joined with Red Hat alongside RHEL and Fedora. However, the people that worked on CentOS stayed separate from RHEL.

On December 8th 2020, The CentOS Project announced the end of CentOS as it was previously known and announced CentOS Stream. AlmaLinux and Rocky Linux among others now provide 1:1 binary compatible releases with RHEL and the original CentOS. The original CentOS will reach end of life December 2021.

## Other websites 
* Official website
David Gilmour

**David Jon Gilmour** CBE (born 6 March 1946) is an English musician, record producer, songwriter. He is most famous for being a guitarist, singer and songwriter in the rock band Pink Floyd. Along with being in Pink Floyd, he has worked as a record producer for other musicians. Gilmour has also recorded and released albums as a solo performer.

Gilmour has always been active with many different charities. He was appointed CBE in 2003 for services to both music and for his charity work.

In 1996, Gilmour was inducted into the Rock and Roll Hall of Fame as a member of Pink Floyd.

In 2003, Gilmour was listed at number 82 in ''Rolling Stone Magazine's list of the "100 Greatest Guitarists of All Time" 

## Discography 
* *David Gilmour* (1978)
* *About Face* (1984)
* *On an Island* (2006)
* *Live in Gdańsk* (2008)
* *Rattle That Lock* (2015)
* *Live at Pompeii* (2017)
* *Luck and Strange* (2024)

## Notes
Network bridge

A **network bridge** is a device which connects two parts of a network together at the data link layer (layer 2 of the OSI model). 

Network bridges work similarly to network switches, but the traffic is managed differently. A bridge will only send traffic from one side to the other if it is going to a destination on the other side. This is different to a layer 1 switch which sends all traffic from either side. Sometimes network bridges are called layer 2 switches. 

Since they need to look at the contents of the traffic going into them, they are much more complicated than a hub or repeater.

## How is it different to a switch? 
Network Switches and Bridges are both Layer 2 devices. They  operate at the Data Link Layer (Layer 2) of the OSI Reference Model. Network Switches and Bridges have many similarities and similar  function. But Switches are considered as superior devices than bridges.

Following are the major differences between  network switches and bridges.

**•** Packet forwarding in Bridges are performed using software. Packet forwarding in Switches are performed using ASICs (Application Specific Integrated Circuits).

**•** Switches operate comparatively higher speeds than Bridges.

**•** Method of switching of a Bridge is store and forward. Method  of switching of a Switch can be store and forward, cut-through or fragment-free.

**•** Normally a Switch has more ports than a Bridge.

**•** Bridges can operate only in half duplex mode, but a Switch can operate both in half duplex or full duplex mode.

**•** Both Bridge and Switch has one collision domain per port, but switches have one broadcast domain per VLAN.

**•** Switches support full-duplex Local Area Network (LAN) communication.

## Related pages
* Shortest Path Bridging
Hydride

A **hydride** is a compound with hydrogen bonded to other elements. Except for a few of the Noble gases, all of the elements in the periodic table can form hydrides. The properties of hydrides can be very different, but some of the hydrides have similar properties. 

*Metallic hydrides*: compounds with ionic bonding. They are very reactive, making them difficult to dissolve. Most alkali metals and alkaline earth metals form ionic hydrides.

*Metallic* or *Interstitial hydrides*: These have metallic properties like good electrical conductivity and thermal conductivity. They are called interstitial because hydrogen can enter the metallic lattice (framework of metal atoms). Metallic hydrides are mostly formed from the metals in the groups 3 to 5 of the periodic table. Some of these are used in the nickel metal-hydride battery.

*Covalent hydrides*: These have covalent bonds between hydrogen and the other element. Most of the p-block elements form covalent hydrides. Many of these hydrides are unstable in air or water or when heated. Hydrocarbons are the hydrides of carbon, ammonia is a hydride of nitrogen, and water is a hydride of oxygen.

## References
Horse the Band

**Horse the Band** is an American hardcore rock band from Lake Forest, California that was started in 1999. They are famous for using video-game style music in their songs.

## Members 
### Current 
* Nathan Winneke - vocals (2003-present)
* David Isen - guitars, (1999-present)
* Erik Engstrom - keyboard (1999-present)
* Daniel Pouliot - drums, (2008-present)

### Former 
* Dashiell Han Arkenstone- bass (2005-2008)
* Eli Green – drums (2005-2006)
* Andy Stokes – bass (2001-2005) 
* Jason Karuza – drums, (1999-2003)
* Christopher Prophet - drums, (2007-2008)
* Adam Crook – vocals (1999-2003)

## Discography 
### Albums 
* *Secret Rhythm of the Universe* (2001)
* *R. Borlax* (2003, Pluto Records)
* *The Mechanical Hand* (2005, Combat Records; re-release, 2007, Koch Records)
* *A Natural Death* (2007, Koch Records)
* *Desperate Living* (2009, Vagrant Records)

### EPs 
* *I Am a Small Wooden Statue on a Patch of Crabgrass Next to a Dried Up Riverbed* (2001)
* *Beautiful Songs by Men* (2002)
* *Pizza* (2006, Combat Records / LIF Records)
### DVDs 
* *The Effing 69 World Tour* tour footage (2004)
### Demos 
* *Scabies, The Kangarooster, and You* (1999)
Thermal conductivity

**Thermal conductivity** is the ability of a material to conduct heat. Metals are good at heat conduction. The thermal conductivity of a material is a defining property that aids in the development of effective heating/cooling technologies. A value for thermal conductivity can be determined by measuring the rate at which heat can pass through a material. 

**Thermal resistivity** is the opposite of thermal conductivity. This means not conducting heat much. Materials with high resistivity are called "thermal insulators" and are used in clothing, thermoses, home insulation, and cars to keep people warm or in refrigerators, freezers, and thermoses to keep things cold. 

Thermal conductivity is often represented by the Greek letter "kappa", \kappa.  The units of thermal conductivity are watts per meter-kelvin.  Watts are a measure of power, meters are a measure of length, and kelvins are a measure of temperature.  From the units, we can see that thermal conductivity is a measure of how much power moves through a distance due to a temperature difference.

Some great thermal insulators are:
Vacuum, Aerogel, Polyurethane

Some great thermal conductors are:
Silver, Copper, Diamond

Silver is one of the most thermally conductive materials (and is relatively common), and because of this there are some cool experiments you can do with silver that show extremely well how thermal conduction works.

One example is when you put 2 spoons in boiling water, one spoon is steel and the other is silver. When you take the spoons out of the boiling water, the silver spoon is hotter than the steel spoon. The reason for this is that silver conducts heat better than steel. The silver spoon will also cool off faster because of this, as it is better at releasing heat.

Another example of silver's thermal conductivity is to put different materials on ice cubes.  An iron washer will just sit on the ice and slowly become colder.  A copper penny will melt through the ice cube and become colder faster.  A silver coin, spoon, or ring on the ice cube will sink into it almost as though the ice cube were made of thick syrup, and the silver will become ice cold almost instantly.  Again, this is because the silver is really good at drawing heat from the air and giving it to the ice cube.  Copper is also good at this, but not as much as silver.
Offa of Mercia

**Offa** was the King of Mercia from 757 until his death in July 796. 
Many historians regard Offa as the most powerful Anglo-Saxon king before Alfred the Great. Offa died in 796 and was succeeded by his son, Ecgfrith, who reigned for less than five months before Coenwulf of Mercia became king.

## King of Mercia 
Offa was the son of Thingfrith, a descendant of Eowa of Mercia. Eowa was a king of Mercia who ruled along with his more famous brother Penda of Mercia. An ealdorman named Beornred took the throne of Mercia but Offa drove him out of Mercia and became king himself that same year.

## Bretwalda (overlord) 
The Anglo-Saxon Chronicle makes no mention of Offa for the years between 757—777. Aethelbert the king of Kent was apparently under Offa's influence before he died in 762. When Egbert of Wessex made a bid for the throne of Wessex in 786 Offa had him banished from England. He made Beorhtric king of Wessex instead. Egbert was welcomed at the court of Charlemagne for at least three years. In charters Offa issued in Kent, East Anglia, Sussex and Middlesex he simply used the style *Rex Merciorum* (Latin for king of Mercia). Only in three church charters does he expand his title to indicate he is overlord of all of England. Letters and presents were exchanged. But when Offa sought a marriage of his son to one of Charlemagne's daughters, relations were quickly cut off. In 787 he convinced the pope to create the position of archbishop of Lichfield in Mercia. He wanted his own archbishop who was closer at hand than the Archbishop of Canterbury. He reorganized the defenses of his kingdom. One of these defenses, Offa's Dyke was a massive earthworks between Mercia and the Welsh kingdoms to the west. Offa died in 796. His son, Ecgfrith, lasted only 141 days as king. Mercia was never again as powerful as it was during Offa's reign.

## Notes
## References
Higgs boson

]]

The **Higgs boson** (or **Higgs particle**) is an elementary particle in the Standard Model of physics. In the 1960s Peter Higgs was the first person to suggest that this particle might exist. On 14 March 2013, scientists at CERN confirmed for the first time that they had found a Higgs particle.

The Higgs particle is one of the 17 particles in the Standard Model, the model of physics which describes all known basic particles. The Higgs particle is a boson. Bosons are thought to be particles which are responsible for all physical forces. Other known bosons are the photon, the W and Z bosons, and the gluon. Scientists do not yet know how to combine gravity with the Standard Model.

The Higgs field is a fundamental field of crucial importance to particle physics theory.

It is difficult to detect the Higgs boson. The Higgs boson is very massive compared to other particles, so it does not last very long. There are usually no Higgs bosons around because it takes so much energy to make one. however, they did not know for certain if this was true.

On 4 July 2012, the teams at the Large Hadron Collider declared that they had discovered a particle which they think is the Higgs boson.

On 14 March 2013 the teams had done much more testing, and announced that they now think the new particle is a Higgs boson.

## References
### Notes 
## Other websites
* The Official Website of ATLAS Project, a leading Higgs Boson research project: 
* Higgs boson -Citizendium
Face (professional wrestling)

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.
Alex Fraser (scientist)

**Alex Fraser** (1923–2002) was an Australian computer scientist. He helped  the modelling of population genetics on computers.  His work made an  on how we view evolutionary systems today.
Heat sink

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.
Haka

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
Endosymbiosis

**Endosymbiosis** occurs when a symbiont lives inside the body or the cells of another organism. It is a very widespread phenomenon in living things.
*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
Four-stroke engine

The **four-stroke engine** is an internal combustion engine. The four strokes are:

## Related pages
* Two-stroke engine
Fagaceae

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.
German Confederation

The **German Confederation** replaced the Holy Roman Empire in Central Europe. After the Holy Roman Empire fell, Germany had fallen into over 350 different small kingdoms. In 1815, the Congress of Vienna decided that these weak kingdoms were not strong enough to keep France from trying to conquer them, which it had already done once under Napoleon. The Congress decided to keep the 39 larger countries that Napoleon had created in his Confederation of the Rhine. He joined 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 might conquer 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.
WrestleMania XXVI

**WrestleMania XXIV** was the twenty-sixth yearly WrestleMania professional wrestling pay-per-view event made by World Wrestling Entertainment (WWE). It took place on March 28, 2010 at the University of Phoenix Stadium in Glendale, Arizona.

Eleven matches took place on the card. The main event saw The Undertaker defeat Shawn Michaels in a No Disqualification Streak vs. Career match. Therefore, Michaels was forced to retire from wrestling and The Undertaker won his 18th match in his undefeated streak. In other matches, Chris Jericho defeated Edge to keep his World Heavyweight Championship, John Cena defeated Batista to win his seventh WWE Championship, Triple H defeated Sheamus, and Jack Swagger won the sixth yearly Money in the Bank ladder match.

## 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. Advertisements telling people about the date tickets would go on sale used the song "Welcome to the World" by Kevin Rudolf.

Along with WrestleMania, 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 class of 2010 was inducted.

## Results 
## Related pages
* List of WWE pay-per-view events

## References
## Other websites
* The Official Website of WrestleMania XXVI
Ice pellets

**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
John Updike

**John Hoyer 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.

## Related pages 
*List of poets from North America

## References
Clog (shoe)

clogs]]
A **clog** is a kind of shoe. There are different kinds of clogs. They can be shoes, sandals or completely made out of wood.
Pecan

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
Dendrite

[[File:Anatomy of neuron.png|thumb|500px|The neuron contains dendrites that receives information, a cell body called the soma, and an axon that sends information. Schwann cells make activity move faster down axon. Synapses allow neurons to activate other neurons. The dendrites receive a signal, the axon hillock funnels the signal to the initial segment and the initial segment triggers the activity (action potential) that is sent along the axon towards the synapse. Please see learnbio.org for interactive version]]

**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
Mischief night

**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.

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&nbsp;— November 2006
* Police Patrol for Mischief Night BBC Merseyside report&nbsp;— November 2006
* Dialect Survey Results  US terms;prevalence and distribution
Tariff

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. Several states may agree to form a larger customs union.

The same word, tariff, is often used for the pricing  of gas and electricity. 

## Related pages 
* Customs
* Indirect tax
* International trade

## References 
*
Shrove Tuesday

**Shrove Tuesday** is a holiday in which Christians have ash put on their heads in the shape of a cross in the United Kingdom, Canada, The United States and Australia for the day before Ash Wednesday. Ash Wednesday is the first day of the Christian season of prayer and  called Lent.

On Shrove Tuesday people traditionally cook and eat pancakes in Britain. The reason for this was to use up foods such as fat, eggs and milk before Lent.

It is also called **Pancake Tuesday** or **Pancake Day** in Britain. In some other countries, such as the United States, it is called Mardi Gras.

In some cultures it has close ties with Mischief night.
Wright County

**Wright County** is a county in three different states of the United States:

* Wright County, Iowa
* Wright County, Minnesota
* Wright County, Missouri
Sicilian language

The **Sicilian language** ('''') is a language spoken in Sicily island and central Calabria. It is spoken by the majority of the inhabitants of Sicily and by emigrants.
## Speakers
10 million people speak the language. It has three stocks: the Sicilian, the Calabro-Sicilian and Salentinu.
## Differences with Italian
Compared to Italian, it is a distinctly separate form of verbal communication patterned by many years of foreign influence. Efforts to force Sicilians to speak conventional Italian include schools, television and radio. Italians maintain that Sicilian is simply a subset dialect of Italian, while Sicilians see their spoken word as a true and separate language.
Portmanteau word

A **portmanteau word** () is made of other words, or parts of words. It comes from putting  two (or more) other words together, like *motel*, from *motor* and *hotel*.

## Origin 
*Portmanteau* originally meant a type of suitcase with two separate parts for storage.
The first use as a word combination appeared in Lewis Carroll's book *Through the Looking-Glass*. There Humpty Dumpty explains that some of the unusual words in *Jabberwocky* are other words packed together into one word, as two parts of a portmanteau suitcase are packed together.

## Examples 
*Portmanteau* itself is an example, combining the French words for carry (porter) and coat (manteau) into a coat carrier. *Wikipedia* is a portmanteau of wiki (Hawaiian for fast) and encyclopedia.

## References 
## Related pages 
*Neologism 
*Blend word
Red Hat

**Red Hat** 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
Lorentz factor

The **Lorentz factor** is the factor by which time, length, and mass change for an object moving at speeds close to the speed of light (relativistic speeds). It is named after the Dutch physicist Hendrik Lorentz.

The equation is:
: \gamma = \frac{1}{\sqrt{1 - (\frac{v}{c})^2}} 
where v is the speed of the object and c is the speed of light. The quantity (v/c) is often labeled \beta (beta) and so the above equation can be rewritten:
: \gamma = \frac{1}{\sqrt{1 - \beta^2}} 

## Classical relativity 
Classical or Galilean relativity is the idea that if you throw a ball at 50&nbsp;mph while running at 5&nbsp;mph, the ball travels 55&nbsp;mph. Of course, the ball still moves away from you at 50&nbsp;mph, so if one were to ask you, you *saw* the ball traveling 50&nbsp;mph. Meanwhile, your friend Rory saw that you happened to be running at 5&nbsp;mph. He would say that the ball was traveling 55&nbsp;mph. Both of you are right, you just happened to be moving *with* the ball.

The speed of light, c, is 670,616,629&nbsp;mph. So if you are in a car traveling half the speed of light (0.5c) and you turn on your headlights, the light moves away from you at 1 c... or is it 1.5 c? It ends up that c is c no matter what. The next section explains why it's not c - 0.5c.

## Time dilation 
When a clock is in motion, it ticks slower by a tiny factor of \gamma. The famous twin paradox says that if there were two twins and twin A stayed on earth while twin B traveled near c for a few years, when twin B got back to earth, he would be many years younger than twin A (because he experienced less time). For example, if twin B left when he was 20 and traveled at .9c for 10 years, then when he got back to earth, twin B would be 30 (20 years + 10 years) and twin A would be almost 43:
: 20 + (10*\frac{1}{\sqrt{1-.9^2}}) = 42.9416
Twin B would not notice that time had slowed at all. To him, if he looked out a window, it would seem like the universe was moving past him, and therefore slower (remember, to him, he's at rest). So time is relative.

## Length contraction 
Things get shorter in the direction of movement when they travel at speeds", which means fast enough that relativity effects can be observed. During twin B's journey, he would notice something strange about the universe. He would notice that it got shorter (contracted in the direction of his motion). And the factor by which things get shorter is \gamma.

## Relativistic mass 
Relativistic mass also increases. It makes them harder to push. So by the time you reach 0.9999c, you need a very big force to make you go faster. This makes it impossible for anything to reach the speed of light.

Still, if you travel a bit slower, say 90% of the speed of light, your mass only grows by 2.3 times. So, while it may be impossible to reach the speed of light, it may still be possible to get close to it—that is, if you have enough fuel.
Howitzer

, Minas Gerais]]

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 *Maine* exploded in Havana Harbor and sank, killing over 260 of those stationed to the boat.

## Related pages
*List of howitzers

## References