cahya/simple-wikipedia huggingface dataset:
A secondary source is a document or recording that writes or speaks about information that is one step removed from the original source. 

The secondary source depends on the  primary source or original source of the information. Secondary sources interpret, evaluate or discuss information found in primary sources. In historiography, a secondary source is a study written by a scholar about a topic. Secondary sources frequently cite primary sources and other secondary sources. They rarely cite tertiary sources.

Example 
A secondary source would be a book on 13th century politics, while the Magna Carta itself would be a primary source.
Many secondary sources use extensive citations in the form of footnotes or endnotes.

Legal use 
The main use of secondary sources in law is to explain the law. They also explain legal concepts. They are used to analyze and describe laws as well as comment on them. Judicial decisions and opinions by qualified experts are secondary sources.

Related pages
Source text
Primary source
Tertiary source

References

Further reading
Primary and secondary sources

Science
Object could mean:

 Object (philosophy), a thing, being or concept
 Physical entity, something that is tangible and within the grasp of the senses
 Object (grammar), a sentence element, such as a direct object or an indirect object
 Object (task), an aim, target or objective
 The intended result of an action
 Object (physics), a collection of masses
 Object, an entity treated by mathematical category theory
 3D model, a representation of a physical object
 Object (National Register of Historic Places), a classification used by the U.S. National Register of Historic Places.
 (As a verb, pronounced: ob-JECT): to make an objection, to say that one disagrees with something. 

Computing
 Object (computer science), a language mechanism for binding data with methods that operate on that data
 Object-oriented programming (OOP), an object is an instance of a class
 Object file, the output of a compiler or other translator program (also known as "object code")
 Object (Information Processing), an information source for an Information Processor
 HTML object tag

Popular culture
 "Object", a song by The Cure from their 1979 album Three Imaginary Boys
 Objects from the 2006 television series The Lost Room
An index is a system used to make finding information easier.

Index could also mean:

 Index (publishing), a detailed list, usually arranged alphabetically, of the specific information in a publication
 Index cards in a rolodex or old card catalog, early and mid 20th century technologies for maintaining such lists
 Index (mathematics), for various meanings of the word in mathematics
 Index (economics), a single number calculated from an array of prices and quantities.
 Index, Washington, a town in Snohomish County, Washington, United States.
 Index (typography), a largely obsolete punctuation mark 

In publications:
 Index Librorum Prohibitorum, a list of publications which the Catholic Church censored
 Germany's List of Media Harmful to Young People, colloquially known as The Index, published by the Bundesprüfstelle für jugendgefährdende Medien
 Index Magazine, was a prominent New York City based publication for art and culture.
 Truman State University Index, the weekly newspaper distributed at Truman State University and throughout the Kirksville, Missouri community.
 The Index, the student newspaper of Kalamazoo College, published since 1877.
 The Index (journal), a European propaganda journal created by Henry Hotze to support the Confederate States of America during the American Civil War.

In computers and information retrieval:
 Index (database), a feature in a computerized database which allows quick access to the rows in a table
 Index (information technology), in computer science, either an integer which identifies an array element, or a data structure which enables fast lookup
 Index (search engine), for supporting information retrieval in search engines
 Webserver directory index, a default or index web page in a directory on a web server, such as index.html
 Subject indexing, describing the content of a document by keywords

Other:
 The Index, an item on the Halo (megastructure) in the Halo series of video games.
 The Index (skyscraper), a tower under construction in Dubai.
 Index (retailer), a defunct UK catalogue retailer formerly owned by the Littlewoods group and known as Littlewoods Index
 Index finger, The second digit of a human hand is also referred to as the index finger, pointer finger, forefinger, digitus secundus, or digitus II.
 Index fund, a collective investment scheme
 Indexicality, in linguistics, the variation of meaning of an utterance according to certain features of the context in which it is uttered
Pedro Santana is a municipality in the Dominican Republic, in the Elías Piña Province, on the border with Haiti, along the left side of the Artibonite river.

Origin of the name
The town, and municipality, was named after Pedro Santana, a general of the Independence wars and first president of the Dominican Republic. He was born in Hincha, now a Haitian city ("Hinche") near the border.

Population
The municipality had, in 2010, a total population of 3,917: 2,120 men and 1,797 women. The urban population was  of the total population.

History
The old small town of Los Cercadillos was elevated, with the present name, to the category of municipal district of Bánica on 16 September 1942 and to the category of municipality by the Law 3208 of 3 March 1952.

Geography
Pedro Santana has an area of  and is at  to the north of Bánica and at  to the north of Comendador.

The limits of the municipality are the Dajabón province to the northwest, the Santiago Rodríguez province to the northeast, the San Juan province to the east, the municipality of Bánica to the south and Haiti to the west.

Administrative division
The municipality of Pedro Santana has only one municipal district; this is:

Economy
The main economic activity of the municipality is farming.

References 

Settlements in the Dominican Republic
1952 establishments in the Dominican Republic
The visual system is the part of the nervous system which allows organisms to see.
It interprets the information from visible light to build a representation of the world surrounding the body. The visual system has the complex task of (re)constructing a three dimensional world from a two dimensional projection of that world. The psychological manifestation of visual information is known as visual perception.

Introduction
This article mostly describes the visual system of mammals, although other "higher" animals have similar visual systems. In this case, the visual system consists of:

 The eye, especially the retina
 The optic nerve
 The optic chiasma
 The optic tract
 The lateral geniculate nucleus
 The optic tectum (superior colliculus)
 The optic radiation
 The visual cortex
 The visual association cortex

Different species are able to see different parts of the light spectrum; for example, bees can see into the ultraviolet, while pit vipers can accurately target prey with their infrared imaging sensors.<ref>	     AB Safer and MS Grace (2004),   "Infrared imaging in vipers: differential responses of crotaline and viperine snakes to paired thermal targets". Behav Brain Res. 154(1):55-61. 2004 Sep 23. </ref>

References

David H. Hubel 1989. Eye, Brain and Vision. New York: Scientific American Library.
David Marr 1982. Vision: A Computational Investigation into the Human Representation and Processing of Visual Information. San Francisco: Freeman.
R.W. Rodiek 1988. The Primate Retina. In Comparative Primate Biology. vol 4 of Neurosciences. eds H.D. Steklis and J. Erwin. pp. 203–278. New York: A.R. Liss.
Matthew Schmolesky, The Primary Visual Cortex 
Martin J. Tovée 1996. An introduction to the visual system. Cambridge University Press. 
Andreas Vesalius 1543. De Humani Corporis Fabrica (On the Workings of the Human Body)
Torsten Wiesel and David H. Hubel 1963. The effects of visual deprivation on the morphology and physiology of cell's lateral geniculate body. Journal of Neurophysiology'' 26, 978-993.

Other websites
"Webvision: The Organization of the Retina and Visual System" - John Moran Eye Center at University of Utah
VisionScience.com - An online resource for researchers in vision science.
Journal of Vision - An online, open access journal of vision science.

Vision
Microform is a name given to special photographic films. Microforms contain reduced images of documents. Usually, documents stored on microform are reduced about 25 times. Microform is mainly used for archival purposes.

There are three common formats:
Microfilm, which comes in reels of film.
Aperture card, This contains additional digital data (as a punch card).
Microfiche, a flat sheet with many pages.

Properly stored (room temperature, 50% humidity), microform should be able to last up to 500 years.

Images

Photography
Storage devices
A microphone, sometimes referred to as a mike or mic (both IPA pronunciation: ), converts sound into an electrical signal.

Microphones are used in many applications such as telephones, tape recorders, hearing aids, motion picture production, live and recorded audio engineering, in radio and television broadcasting and in computers for recording voice.

Kinds of Microphones 
Sound passes through the air in waves, and as was said above, the microphone turns the sound wave into an electrical wave.  Different kinds of microphones will turn the sound waves into electricity in different ways.

 Carbon button - This is the first kind to become commonplace, being used in most 20th century telephones. Sound waves, by compressing and decompressing a piece of carbon, change the amount of electric current flowing in the wire, thus creating electrical waves. This kind became rarer late in the century, due in part to lack of high fidelity. 
 Dynamic - This uses a round plastic or rubber disk connected to a wire coil in order to turn sound into electricity.  The sound wave hits the disk which vibrates as a result.  This vibration moves the coil back and forth near a magnet very quickly in order to create an electrical current.  The dynamic microphone is the exact opposite of a speaker which uses an electrical current to move the coil, which moves the disk.  Then the disk makes sound.
 Ribbon - This is similar to a Dynamic microphone.  A thin, small sheet of metal (tin or aluminum usually) hangs between two magnets.  When sound hits the thin piece of metal, the metal vibrates.  That vibration creates an electrical signal in the metal.
 Condenser - This uses two small metal plates to create an electrical current.  Basically two  small metal plates are placed very near to each other and electricity is run through the plates.  This creates an electric field between the two plates.  When sound hits these plates, the plates vibrate.  The vibration makes small changes in the electric field.  These changes create the electrical signal.
 Crystal or ceramic microphones use piezoelectricity.

Equipment 
A pop filter (or pop shield) is often used in recording studios.  It is an electronic filter that reduces or eliminates 'popping' sounds caused by fast moving air (such as air from the mouth).

History
The first microphones were invented as telephone transmitters. They included liquid and dynamic designs. Carbon transmitters were later used in this and other applications.

Related pages
 Loudspeaker — The inverse of a dynamic microphone

Other websites 

 Info, Pictures and Soundbytes from vintage microphones
 Microphone construction and basic placement advice 
 History of the Microphone 
 Microphone sensitivity conversion — dB re 1 V/Pa and transfer factor mV/Pa
 Large vs. Small Diaphragms in Omnidirectional Microphones

References

Sound
Engineering
Data input
Audio technology
Digital signal can mean two different things: 
 discrete-time signals that are digitized.
 the waveform signals in a digital system.

Discrete-time signals 

Digital signals are digital representations of discrete-time signals, which are often produced by changing an analog signal.

An analog signal is a datum that changes over time (for instance the temperature at a given place; the depth of a certain point in a pond; or the amplitude of the voltage at some node in a circuit). A discrete-time signal is a sampled version of an analog signal: the value of the datum is noted at fixed intervals (for example, every microsecond) rather than continuously.

In short, a digital signal is a quantized discrete-time signal; a discrete-time signal is a sampled analog signal.

In the digital revolution the usage of digital signals has increased significantly.
Many modern media devices, especially the ones that connect with computers use digital signals to represent signals that were traditionally represented as analog signals; cell phones, music and video players, personal video recorders, and digital cameras are examples.

In most applications, digital signals are represented as binary numbers, so their precision of quantization is measured in bits.

Waveforms in digital systems

In computer architecture and other digital systems, a waveform that switches between two voltage levels representing the two states of a Boolean value (0 and 1) is referred to as a digital signal.

The clock signal is a special digital signal that is used to synchronize digital circuits.
The image shown can be considered the waveform of a clock signal.
Logic changes are triggered either by the rising edge or the falling edge.

Engineering
Telecommunications
Pneumatics is the use of compressed air for mechanical motion.  It has many uses. 

Pneumatic transfer systems are employed in many industries to move powders and devices. Pneumatic devices are also used where electric motors cannot be used for safety reasons, such as deep in a mine where explosive dust or gases may be present.

Examples of pneumatic tools 

 Pneumatic drill (jackhammer) used by road workers
 Pneumatic nailgun
 Pneumatic switches
 Pneumatic actuators
 Air compressors
 Vacuum pumps
 Barostat systems used in Neurogastroenterology and for researching
electricity
 Cable Jetting - a way to install cables in ducts
 Pneumatic mail systems
 Air brakes on buses, trains, and trucks

Comparison to Hydraulics

Both pneumatics and hydraulics are applications of fluid power. Pneumatics uses air, which is compressible, while hydraulics uses relatively incompressible liquid media such as oil or water.

Advantages of pneumatics 

 The working fluid is very light in weight so supply hoses are not heavy.

 Because the working fluid is (mostly) just air, there is usually no need for a return line for the working fluid and leaks of the working fluid tend not to be messy.

 Because air is compressible, the equipment is less likely to be damaged by shock.  The air in pneumatics absorbs excessive force, whereas the fluid of hydraulics directly transfers force.

Advantages of hydraulics 

 Higher energy density owing to the much higher working pressures usually employed.

 The hydraulic working fluid is basically incompressible, leading to a minimum of spring action. When hydraulic fluid flow is stopped, the slightest motion of the load releases the pressure on the load; there is no need to "bleed off" pressurised air to release the pressure on the load...

References

Other websites 

 www.pneumatics.be - didactic website - for students - how pneumatics works
 U.S. Department of Energy  - Improving Compressed Air System Performance
 Fluid Power Educational Foundation  - Advancing and Supporting Hydraulic & Pneumatic Education
 Pneumatics Glossary  - Glossary of Pneumatic Terms

Mechanics
Saxe-Gotha () was a state in today's Thuringia, Germany.

It was created in 1640 for Duke Ernest I and ended in 1680 when his lands were divided after his death in 1675. The area around Gotha passed to Ernest's eldest surviving son, Frederick of Saxe-Gotha-Altenburg, who also inherited Altenburg (which Ernest had inherited through his wife Elisabeth Sophie) and became Duke of Saxe-Gotha-Altenburg.

Dukes of Saxe-Gotha 
 Ernest I the Pious (1640 – 75, also Duke of Saxe-Altenburg from 1672)
 Divided into Saxe-Gotha-Altenburg, Saxe-Coburg, Saxe-Meiningen, Saxe-Römhild, Saxe-Eisenberg, Saxe-Hildburghausen and Saxe-Saalfeld in 1680

When the house of Saxe-Gotha and Altenburg became extinct in 1825, Saxe-Gotha-Altenburg was split. Saxe-Gotha passed to the Duke of Saxe-Coburg-Saalfeld who in turn gave Saalfeld to Saxe-Meiningen. The Duke of Saxe-Hildburghausen became Duke of Saxe-Altenburg, and gave Saxe-Hildburghausen to Saxe-Meiningen.

After the abolition of German monarchies at the end of the First World War it became a part of the newly created state of Thuringia in 1920.

References 
 Saxe-Gotha , Columbia Encyclopedia, Sixth Edition, Columbia University Press (2001 – 05), accessed January 27 2007

1572 disestablishments
1640 establishments
House of Wettin
States of the Holy Roman Empire
Thuringia
1640s establishments in Europe
The Dominican city of Comendador is the head municipality of the Elías Piña province, on the border with Haiti.

Population
The municipality had, in 2010, a total population of 19,344: 9,675 men and 9,669 women. The urban population was  of the total population.

History
The city was founded in 1868, and named after Nicolás de Ovando, the "Comendador of Lares" (Comendador was the chief of a military or religious order). It was founded where there was a military post close to the border with Haiti. The Taíno name of the region was Duan.

There was several fights between Haitian and Dominican soldiers during the Dominican-Haitian War after 1844. The most important fight was the La Estrelleta Battle in a savanna near Comendador.

The old military post was made a Cantón (now called Municipal District) of the Azua province in 1907. The next year, in 1908, it was elevated to the category of municipality of the same province.

Its name was changed to Villa Elías Piña on 29 November 1930. In 1972, its name was changed back to Comendador..

Geography
Comendador is at  to the west of Santo Domingo and    of San Juan de la Maguana. The limits of the municipality are the municipality of Bánica to the north, the San Juan province to the east, the municipality of El Llano to the south and Haiti to the west.

The average daily temperature in the city is  and the average rainfall for the year is .

Administrative division
The municipality of Comendador has two municipal districts; these are:

Economy
The main economic activity of the municipality is agriculture. Commerce with Haiti is also an important economic activity in the city.

References 

Settlements in the Dominican Republic
1868 establishments
1860s establishments in the Dominican Republic
Antoni Lange (1861 or 1863 – March 17, 1929), was a Polish poet, translator and mystic philosopher of the Symbolism and Parnassianism movements. He was regarded as a "great master of reflective poetry". He spoke 15 languages. His pen-names were Antoni Wrzesień and Napierski. Although Lange was not a particularly famed author, many people call him "a magican of lyrical form" because of his unquestionable mastery in using rare poetic forms and innovation,s which makes him a pioneer of modern collage and even imagism movement.

As a religious thinker Lange was one of the first to make people interested in Indian philosophy and literature in Poland. His existential reflection of "universal pain" (wszechcierpienie) unites Christian mysticism with traditions of Buddhism.

Lange was also an uncle of the poet Bolesław Leśmian.

Life 
He was born in 1861 or 1863 into a patriotic Jewish family who were heavily influenced by the messianic ideals of Romantic Polish poets, especially Adam Mickiewicz. In 1830, his father Henri Lange took part in the November Uprising.

"Lange's own poems did not win him recognition, and the last phase of his life was poisoned by feelings of bitterness". He never married and had no children.

Works 
Eternal solitaries - human souls,
Solitaries blown astray;
Each wanders through the Milky Way,
Each in her finite circle rolls.

Like wandering planets they gaze
At one another in the sky's blue halls;
Each in her finite circle rolls,
But never from her orbit sways.

Bibliography

Poems 
 Sonety wedyckie (1887)
 Pogrzeb Shelleya (1890)
 Wenus żebracza (1890)
 Ballady pijackie (1895)
 Księgi proroków (1895)
 Logos (1895)
 Poezje (I – 1895; II – 1898)
 Pogrobowcom (1901)
 Świat (1901)
 Fragmenta. Poezje wybrane (1901)
 Pocałunki (1902)
 Deuteronomion (1902)
 Akteon (1903)
 Księgi bogów (1903)
 Rozmyślania (1906)
 Pierwszy dzień stworzenia (1907)
 XXVII sonetów (1914)
 Ilia Muromiec (1916)
 Trzeci dzień (1925)
 Groteski. Wiersze ironiczne (1927)
 Rozmyślania. Z nowej serii (1928)
 Gdziekolwiek jesteś (1931)
 Ostatni zbiór poezji (1931)

Novels and short stories 
 Godzina (1894)
 Elfryda: nowele i fantazje(1895)
 Zbrodnia (1907)
 Dwie bajki (1910)
 Czterdzieści cztery (1910)
 Stypa (1911)
 W czwartym wymiarze (1912)
 Miranda (1924)
 Nowy Tarzan (1925)
 Róża polna (1926)
 Michałki (1926)

Plays 
 Atylla (1898)
 Wenedzi (1909)
 Malczewski (1931)

Essays 
 O sprzeczności sprawy żydowskiej (1890)
 Analfabetyzm i walka z ciemnotą w Królestwie Polskim (1892)
 O poezji współczesnej (1895)
 Studia z literatury francuskiej (1897)
 Studia i wrażenia (1900)
 Lord Byron (1905)
 Rzuty (1905)
 Panteon literatury wszechświatowej (1921)
 Pochodnie w mroku (1927)

References

1863 births
1929 deaths
Jewish writers
Polish novelists
20th-century Polish philosophers
Polish playwrights
Polish poets
Polish Jews
Polish translators
Writers from Warsaw
The curie (symbol Ci) is a unit of measurement. It measures  radioactivity. It is defined as

 1 Ci = 3.7×1010 decays per second.

This is roughly the activity of 1 gram of the radium isotope 226Ra. Radium was studied by the pioneers of radiology, Marie and Pierre Curie so the unit is named after them. The curie has since been replaced by an SI derived unit, the becquerel (Bq), which is decay per second. Therefore:

 1 Ci = 3.7×1010 Bq or 37 Gigabecquerel (Gbq)

and

 1 Bq = 2.70×10−11 Ci

In 1962, the International Commission on Radiological Units suggested the usage of this unit named after Marie Curie.

Old units of measurement
A fjord or fiord is a type of gulf. Fjords are narrow with steep sides, and are created by large masses of snow moving over land. They can be found in Norway, Sweden, Denmark, Canada, Germany, and Finland. In Germany, fiords are called Förde.

Cities 
Most cities near fiords are sea ports. Some cities near fjords are listed below:

 Lübeck, Germany;
 Kiel, Germany;
 Flensburg, Germany;
 Schleswig, Germany;
 Orebro, Denmark;
 Vaile, Denmark;
 Horsens, Denmark;
 Kungsbacka, Sweden;
 Nykarleby, Finland;
 Tornio, Finland
 Sangi, Sweden;
 Tore, Sweden;
 Hudiksval, Sweden
 Hopedale, Canada

Gulfs
The raccoon (Procyon lotor, common raccoon,) is a mammal. Raccoons are curious, clever, and solitary. They are originally from North America. They have spread through Central America, and live in various habitats. They have escaped in some parts of Eurasia (see map), and now live there as well. They are omnivorous. Raccoons are in the family Caniformia, and are related to the mustelids.

The raccoon has short legs, pointed nose, small ears, grayish-brown fur, and a bushy tail.

The raccoon's most distinctive features are its multi-purpose front paws, its facial 'mask', and its striped tail. moreover, Raccoons are noted for their intelligence. Studies show they are able to remember the solution to tasks for up to three years. Raccoons are usually nocturnal. Their food is about 40% invertebrates, 33% plant foods, and 27% vertebrates. Raccoons are omnivores. They eat mice, squirrels, rabbits, birds, fish, frogs, turtles, lizards, eggs, insects, worms, fruit, berries and nuts. Their predators include red foxes, wolves, coyotes, bears, eagles, owls, cougars, lynx and bobcats.

Most raccoons live in the wild. Being around humans does not bother them. They often nest in empty buildings, garages, sheds, and even the attics of houses. Raccoons do not hibernate in the winter. Those that live further north where it is colder, grow thick coats to keep them warm and spend long periods sleeping. Raccoons that live in captivity can survive up to 20 years. In the wild, they usually live only 1–3 years.

Two other species of raccoon, the crab-eating raccoon (P. cancrivorus) and the Cozumel Island raccoon (P. pygmaeus), are extremely similar to the common raccoon. The crab-eating raccoon is quite widespread in eastern South America.

After a gestation period (pregnancy) of about 65 days, two to five young are born in spring. Newborn raccoons are called "kits".

A raccoon climbed a building in Minnesota.

References

Other websites

Raccoons Removal

Procyonids
Mammals of North America
Omnivores
Sandy Wayne Robson (born November 6, 1973 in Peterborough, Ontario) is a Canadian actor. He is probably best known for hosting the game show Trash to Treasure and his role as "Dude" in The N's television series About a Girl.

Biography
A Toronto native, Robson's breakthrough role was in Crazy Canucks, the story of the 1974 World Cup ski champions. (His background as a giant slalom down hill skier was useful for the film.) More recently, he has acted in Cow Belles and The Cheetah Girls, and the television series Kevin Hill, Sue Thomas: F.B.Eye, and Instant Star. Sandy has starred in many theatrical productions, including the one man show Full Committed, in which he played 40 characters.

Television
 About a Girl (2007) - Dude.
 Trash to Treasure (2003) - Host.

Guest appearances
 Twice in a Lifetime (1999) - Handler #1.
 In a Heartbeat (2000) - Guttman.
 Sue Thomas: F.B.Eye (2004) - Justin.
 Kevin Hill (2005) - Major Paul Cahan.
 Instant Star (2006) - Ken.
 Psych (2008) - Logan.

Filmography
 The Impossible Elephant (2001) - Lenny.
 Twas the Night (2001) - Harry.
 Out of the Ashes (2003) - Leiku's husband.
 The Cheetah Girls (2003) - Firefighter.
 Crazy Canucks (2004) - Jungle Jim Hunter.
 The Winning Season (2004) - Dots Miller.
 Cow Belles (2006) - Thomas.

Other websites
 
 

1973 births
Canadian television actors
Living people
People from Ontario
Canadian television presenters
In Anglican church music, a Service is a piece of music for the choir to sing during a service of worship.   It uses the words which are a traditional part of the service.  The choir is usually accompanied by the organ, but sometimes it can be just for choir without organ.

In Morning Prayer the words which are set to music for the choir are the words of the Venite (Psalm 95), the Te Deum and the Jubilate (Psalm 100) or Benedictus.

For a Holy Communion the set words will usually be the Gloria, sometimes the Creed, Sanctus, Agnus Dei as well as responses.

For Evening Prayer the words will be the Magnificat and the Nunc Dimittis.  Singers in the choir often call these "Mag and Nunc" for short.  Many composers have set these words.  They make them into a piece for choir which is like an anthem.

In the Tudor and early Stuart periods, services were described as "Short", "Great" or "Verse" services.  Short services were short, the words were only sung once and it was often unaccompanied (no organ).  A Great service was longer: some of the words were often sung many times.  William Byrd wrote a famous Great Service.  A Verse service was also long: there were several verses which need to be sung by a solo choir member.  In between each verse there is some music for the whole choir to sing.

Musical forms
Christian music
A space station is a artificial satellite in space that people can live at. All past and current space stations have been in low Earth orbit. Space stations can dock with other spacecraft. This allows transferring cargo and people. At present the International Space Station is the only space station in orbit. The first space station was Salyut 1. Prior stations were the seven Salyut stations, Skylab, Mir and the two Tiangong stations. The Chinese Space Station is planned for the future.

Space stations are used to learn about how being in space for a long time effects the human body. They also are a place for science experiments and research. Space stations have been designed for more than one crew. Each crew member may stay aboard the station for weeks or months, and then is replaced by others. Some have spent more than one year at a time on a space station. This includes Vladimir Titov, Musa Manarov, Sergei Avdeyev and Valeriy Polyakov aboard Mir.

List of successful stations 
The below list is of stations that made it to orbit and had at least one crew visit them. There have also been a few stations that have failed or were for testing. Those are not included on this list.

Notes

References
A time server is a special computer in a computer network. 

It is important that computers on a network use the same time. Time servers use an atomic clock, or they ask other computers on the network about the time. They then tell this time to all the other computers in the same network. Common protocols to do this are the Daytime Protocol and the Network Time Protocol (NTP).

NTP calls the quality of a time server its stratum.  Stratum can be anything form 0 to 255 and lower is better. It is rare to see a network with a source worse than stratum 5.
Stratum 0 time sources are the actual clocks that track the time, usually an atomic clock or GPS receiver.
Stratum 1 time sources are what most people mean when they talk about a time server.  They get their timing information from a master clock and send it out to the network.
Stratum 2 time sources are computers that get their clock information from a stratum 1 time server.  They use NTP to talk to each other as well as their stratum 1 servers so they can have the best time information possible.

Every level that is added of time servers getting information from a source close to the master clock and passing it farther away from the master clock increases the stratum level.

computers
internet
Ashley Marie Massaro (May 26, 1979 – May 16, 2019), also known simply as Ashley, was an American pictorial model and professional wrestler. She is best known for her time with World Wrestling Entertainment (WWE) while wrestling on its Raw brand. 

She was the winner of the Raw Diva Search 2005 and was on the cover of the April 2007 issue of Playboy Magazine. She was a contestant on the fifteenth season of Survivor in China, but was the second contestant to be eliminated.

Massaro was found dead at her home on May 16, 2019 in Long Island, New York at the age of 39. The cause of death was suicide by hanging.

References

Other websites 
TheAshleyMassaro.com 

WWE.com Profile
Ashley Massaro in Maxim Magazine

Ashley's Survivor: China Profile

1979 births
2019 deaths
Sportspeople who committed suicide
Suicides by hanging in the United States
American professional wrestlers
Female professional wrestlers
Sportspeople from New York
Melina Nava Pérez (born March 9, 1979; ring name Melina) is an American professional wrestler and manager. She is best known for working for World Wrestling Entertainment (WWE) where she wrestled on its Raw and SmackDown brands. She was released from her contract with the WWE on August 5, 2011.

Early life 
Pérez began her career as a model. In 2000, she decided to become a professional wrestler and began training. Pérez's pro-wrestling debut was in 2002 on a tour of the independent wrestling scene. She joined a number of California-based promotions such as the Empire Wrestling Federation (EWF).

World Wrestling Entertainment 
Pérez began working in World Wrestling Entertainment's "farm territory" Ohio Valley Wrestling (OVW) in March 2004 when she was kayfabe brought her in as a way to taunt her ex-boyfriend John Hennigan. Melina, however, aligned herself with Hennigan, who later changed his ring name to Johnny Nitro. Soon after, Nitro began teaming with Joey Matthews, later known as Joey Mercury. On November 10, the trio, now known as MNM, won the OVW Southern Tag Team Championship.

2005 
MNM made their debut in WWE on the April 14, 2005 edition of SmackDown! by interrupting the first ever Carlito's Cabana interview segment. Rey Mysterio, one half of the WWE Tag Team Champions, was a guest. Melina insulted Mysterio and had Mercury and Nitro attack him. This led to MNM's first match the next week on SmackDown! for the tag team title. MNM won the match against Mysterio and Eddie Guerrero, giving them their first WWE Tag Team Title reign.

While managing the Tag Team Champions, Melina started wrestling against the other WWE Divas. She had her first match on June 30 against Michelle McCool.  Her first pay-per-view match – a Bra and Panties match – was at The Great American Bash against Torrie Wilson. Melina won both matches.

2007 
On January 29, 2007, Melina became the number 1 contender for the WWE Women's Championship. On February 5 Melina lost a title match against Mickie James. On February 19, Melina won the Women's Championship from James.  On April 24 at a show in Paris, France, Melina lost the Women's Championship in a Triple Threat match to James when James pinned Victoria. In a rematch on the same night, she pinned James to regain the title and become a two-time WWE Women's Champion.

On May 7 Melina was defeated in a tag team match when she was pinned by Candice Michelle. Melina lost to Candice in several tag team matches, as well as in non-title bouts over the next few weeks. At Vengeance, Melina lost the Women's Championship to Candice, and failed to wim the title back at The Great American Bash.

References

Other websites
Official website
Melina's WWE Alumni profile

1979 births
Living people
American professional wrestlers
Former WWE wrestlers
Female professional wrestlers
Sportspeople from Los Angeles
Amy Christine Dumas (born April 14, 1975)
better known by her ring name Lita, is an American former World Wrestling Entertainment (WWE) wrestler and valet. While working with WWE from 2000 to 2006, she became one of the most popular female wrestlers in the company's history.

Career
After working for a short time on the independent circuit and in Extreme Championship Wrestling, Dumas began working with the World Wrestling Federation in 1999. Originally, she was paired with Essa Rios. She became more well know when she teamed up with Matt and Jeff Hardy as Team Xtreme. During her career, she won the WWE Women's Championship four times.

Dumas had an off-screen relationship with Matt Hardy. It ended in 2005 after her affair with Adam Copeland. WWE used the problems between them as part of a story during 2005 and 2006. The affair was part of the reason Hardy was fired in 2005, but he was rehired later in the year. As a result of her personal life, Dumas' character Lita began to be "booed" for the first time by the fans during this time.

After she stopped wrestling in 2006, she became the lead singer of punk rock band The Luchagors. The band released their self-titled CD, The Luchagors on September 11, 2007. She will be inducted into the WWE Hall of Fame in 2014.

References

Other websites
 Official website
 

1975 births
American punk musicians
American professional wrestlers
Female professional wrestlers
Former WWE wrestlers
Living people
People from Fort Lauderdale, Florida
Singers from Florida
Sportspeople from Atlanta, Georgia
Sportspeople from Florida
WWE Hall of Fame
Specific Gravity (SG) is a special case of relative density.

It is defined as the ratio of the density of a given substance, to the density of water (H2O). Substances with a specific gravity greater than 1 are heavier than water, and those with a specific gravity of less than 1 are lighter than water.

SG is by definition dimensionless and therefore not dependent on the system of units used (e.g. slugsft−3 or kgm−3), assuming that the units are consistent. Based on the SG-value of a given substance, the density of that substance can be calculated.

Related pages
 Buoyancy
 Fluid mechanics
 Relative density

References

 Fundamentals of Fluid Mechanics Wiley, B.R. Munson, D.F. Young & T.H. Okishi
 Introduction to Fluid Mechanics Fourth Edition, Wiley, SI Version, R.W. Fox & A.T. McDonald
 Thermodynamics: An Engineering Approach Second Edition, McGraw-Hill, International Edition, Y.A. Cengel & M.A. Boles

Physics
The Rosetta Stone is a stone with writing carved into it. There are 3 types of writing on the Rosetta stone; Greek, Egyptian, and another form of Egyptian writing. French soldiers found it in Egypt in 1799. It helped people get a better understanding of the Ancient Egyptian writing system called hieroglyphics. Its discovery led to the translation of Ancient Egyptian writing.The stone is named after the city where it was found, Rosetta (also called Rashid). The stone is now in the British Museum in London.

It had three pieces of writing on it that said the same thing in two different languages. Two pieces of writing were written in Ancient Egyptian, but in two different scripts: Demotic and hieroglyphics. The third writing was written in Ancient Greek.

The historians could already read the Greek. Using this knowledge they were able to work out how to read the Egyptian scripts.

The complete Greek text, in English, is about 1600–1700  words in length. The text is a royal decree from the Hellenistic period about the taxes of temple priests. It gives them back the tax privileges they had earlier. Some scholars believe that several copies of the Rosetta Stone might exist, as this proclamation must have been made at many temples.

The discovery of the stone 
The soldiers who discovered the stone were part of Napoleon Bonaparte's 1798 campaign in Egypt. It was given to the British as part of the surrender arrangements when French forces were caught in Alexandria by the Battle of the Nile and a larger force of British and Ottoman troops. The surrender and treaty is called the Capitulation of Alexandria. Under the treaty, the French had to hand over their archaeological discoveries to the British, and that included the Rosetta Stone.

The discovered part of the stone is 114.4 centimeters (45 in) high at its tallest point, 72.3 centimeters (28.5 in) wide, and 27.9 centimeters (11 in) thick.

Part of the text 
These are some of the translated words on the stone:

References

Other websites 
 A Rosetta Stone website
 Rosetta Stone -Citizendium

Ancient Egypt
British Museum
A curtain is a piece of cloth used to block light, water, or cold air from entering a place (some curtains are better at blocking than others because of the type of fabric used). Curtains are hung around showers to keep water off the floor around the shower.  Curtains are also hung around windows to keep light from coming in. A curtain is raised and lowered during a play or other theatrical production. Curtains can come in many different colors and different types of fabric. It is also originally a French word.

Curtains can also be made from air.

Cloth
A visitor is a person who does not permanently live in a place. If someone says "I am a visitor here", that means that they do not live in that place all the time.

Related pages
Hospitality

Social sciences
Half-time is the name of a break in the middle of a sports game. This break gives players a chance to rest. It also gives watchers of the game time to stretch, eat, or go to the bathroom without missing the game. During half-time, there is usually a show on the field of play. It may include a marching band or something like it. This is called a half-time show. There is a half-time show in the Super Bowl. Half time is usually 15 minutes, but in the Super Bowl it is usually about 30 minutes to give time for advertisements and performances. In Football, teams usually switch sides at the beginning of the next half.

Sports with half-time 
American football 
Field hockey
Lacrosse
Football (soccer)
Field hockey
Rugby football
Basketball
Netball

Sports words
Fluid mechanics is the study of how fluids move and the forces on them. (Fluids include liquids and gases.)

Fluid mechanics can be divided into fluid statics, the study of fluids at rest, and fluid dynamics, the study of fluids in motion. It is a branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms.

The study of fluid mechanics goes back at least to the days of ancient Greece, when Archimedes made a beginning on fluid statics. However, fluid mechanics, especially fluid dynamics, is an active field of research with many unsolved or partly solved problems. Fluid mechanics can be mathematically complex. Sometimes it can best be solved by numerical analysis, typically using computers. A modern discipline, called Computational Fluid Dynamics (CFD), is devoted to this approach to solving fluid mechanics problems.

Relationship to continuum mechanics 
Fluid mechanics is a subdiscipline of continuum mechanics, as illustrated in the following table.

Related pages
 Applied mechanics
Hydraulics

References

Further reading 
 White, Frank M. (2003). Fluid Mechanics. McGraw-Hill. 
 Cramer, Mark. "The Gallery of Fluid Mechanics"

Other websites 
 CFDWiki—the Computational Fluid Dynamics reference wiki.
Meroë (Meroitic: Medewi or Bedewi) is the name of an ancient city. What remains of the city is on the east bank of the Nile  about 6 km north-east of the Kabushiya station near Shendi, Sudan. It lies about 200 km north-east of Khartoum.
There are a few villages nearby. They are called  Bagrawiyah.

Meroë was the capital of the Kingdom of Kush for several centuries. The Kushitic Kingdom of Meroë gave its name to the "Island of Meroë", which was the modern region of Butana, a region bounded by the Nile (from the Atbarah River to Khartoum), the Atbarah, Ethiopia, and the Blue Nile.  The city of Meroë was on the edge of Butana and there were two other Meroitic cities in Butana, Musawwarat es-Sufra and Naqa.  

The site of the city of Meroë is marked by over two hundred pyramids in three groups. Of many of these pyramids, there are only ruins left.

History of Africa
Cities in Sudan
Jebel Barkal, also called Gebel Barkal, is a small mountain in Sudan. It is about 400 kilometers (248.6 miles) north of a city called Khartoum.  This mountain is about  high and has a flat top.

Mountains of Africa
Sudan
A herbaceous plant is a plant that does not have much wood and its stems are green and soft. These plants grow fast and produce flowers and many seeds in a short period of time.

In Botany, the word for a herbaceous plant is herb (from Latin herba, "grass") but it is common to use the word herb only for plants that are used in perfumes, medicines and for cooking, even if they are not herbaceous plants.

Herbaceous plants may be annuals, biennials or perennials but most are annuals and die at the end of their growing season (the time when they produce flowers, fruits and seeds), leaving their seeds on the soil; those seeds will produce new plants with good weather. Wheat and pea are annual herbaceous plants.

Biennial and perennial herbaceous plants will live for two or more years but the stems that are in the air will die every year; the underground stems will form the new aerial stems (stems that are above the ground). Underground roots and stems can resist more the bad weather (winter or a very dry season) than leaves and stems that are above the ground. Bulbs are biennal and peonies are perennial herbaceous plants

Most herbaceous plants are small and their stems are not thick because they do not have much wood but there are some cases of big herbaceous plants. Bananas and papaya (a tropical fruit) are herbaceous plants but they look like trees; papaya has a thick stem but without much wood.

Herbaceous plants are the first plants with flower that come to live in barren lands (lands without plant life) because they are small and produce many seeds. They are also found in places where the weather conditions are not good for most plants; they can use the little rain that falls in deserts, and they can get enough heat to grow where the soil is covered with snow and ice most of the year, like in very high mountains.

References 

Types of plants
A trophy is an object given to someone because of an accomplishment. These are often given out through sporting events.  

A trophy can be in the shape of a cup, a bowl, a plaque, a mug (these usually painted or engraved with something), a human shape (like the Emmy Award), or a spaceship (like the Hugo Award for science-fiction).  

Trophies can also be an animal head. These are often taken as trophies by hunters.

History

In ancient times people would take heads or other body parts of enemies they had killed in a battle to show how good a warrior they were.
Many years ago (in Ancient Greece and Ancient Rome) the winners did not get any trophy, only a wreath (a wreath is made of flowers and looks like a crown). The winner also got olive oil in a container that was similar to today trophies. In local games, the winners got different trophies, such as a vase or a silver cup.
In ancient Rome, the tradition of getting trophy was slowly forgotten and money were given instead.
Trophies were introduced back in the world on large scale in last century. Football, rugby and baseball trophies were introduced.
Today trophies are mostly made from plastic and are easily accessible to public thanks to low price.
Defoliants are a type of chemical that destroys plants like trees, bushes and grass .

A very common defoliant is Agent Orange used by the US Airforce in the Vietnam War to destroy cover of the enemy. It killed the rainforest and caused birth defects as well as other illnesses among Vietnamese and US soldiers

References

Poisons
Chemical compounds
The Phoenix Lights (sometimes called the "Lights over Phoenix") were a light phenomenon that occurred on March 13 1997 over Arizona and Nevada, in the United States. Some claim that they were UFOs. The governor of Arizona also said he thought they could be UFOs. The thing was V-shaped with 5 lights at the bottom of it in V-formation.

1990s in Arizona
1997 in the United States
March events
Year 909 (CMIX) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar.

Events

Events 
 The Maya leave their biggest towns and cities.

Births 
 Saint Dunstan, Archbishop of Canterbury

References
The continental crust is the layer of granitic, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves.

It consists mostly of feldspar and other sialic rocks. It is less dense than the material of the Earth's mantle, which consists of mafic rock. Continental crust is also less dense than oceanic crust, though it is considerably thicker; mostly 35 to 40 km versus the average oceanic thickness of around 7–10 km. About 40% of the Earth's surface lies on-top of continental crust.

The continental crust is separated from the oceanic crust by the continental margin.

Related pages 
 Oceanic crust

References 
 Butler, Rob, Making new continents  Accessed 01/29/2006
 Saal, A.L., Rudnick R.L., Ravizza G.E. & Hart S.R., 1998. Re-Os isotope evdence for the composition, formation and age of the lower crust. Nature, 39317, 1998.
 Taylor and McLennan, 1995, Model of growth of continental crust through time in John Victor Walther, 2005, Essentials Of Geochemistry, Jones & Bartlett, 
 von Huene, R. and D.W. Scholl, 1991. "Observations at convergent margins concerning sediment subduction, subduction erosion, and the growth of continental crust." Reviews of Geophysics, 29, 279-316.

Other websites
Average composition of Continental Crust
Crust 5.1

Geology