天生一对

我真的不知道应不应该继续这两段友情.Natalie's & Nicky's.

还是先说Nicky的吧.自从上学期认识他之后到现在都已经不短的一段时间了,这个学期更有3堂跟他一起上,之间都已经很熟悉了.但就是因为熟悉,就会发现更多的问题.渐渐觉得他有很多的习惯跟做法都是我看不惯的,与我的原则背道而驰的.我当然明白我不能要求每个朋友都有与我一样或者比我更严格的原则,即使我以前的朋友我也有看不惯的时候,但是对于Nicky这种感觉实在来得太频繁了,以致于渐渐想结束或者放淡我们之间的关系.但是如果我不说出来,他就一定不会觉察,那就不会有结束的时候,我就要一直背着这种不舒服很久很久...到底要选择对不起自己,还是对不起别人?

另外一个就是Natalie.这个星期自从唱K之后,我就只有今天(星期五)第一堂下课的时候去跟她说过一句话,告诉她做test的时候要快一点.一个以前每天都要见好几次的friend,突然间好像消失了,3天没跟她说过一句话,她完全就像不care一样.甚至还我3块钱就是托Kenny还我.你把这当作一个找话跟我说的理由也好啊?当付出很多却得不到一点回报的时候,真的会很不舒服.今晚在church她也只跟我说过很有限的几句话. 甘,这段友情又应该继续还是不呢?

唯一不担心的也许是他们之间的吧...他们会很配的..一定会是的.Natalie虽然像男孩子,但她最后找到的男朋友一定是那种要她照顾的.而Nicky,一定会有一个很会照顾他而又任劳任怨的GF吧.嗯,天生一对.他们.

我,不过是一个不知道该不该离开的Outsider.

GDP - Gross domestic product

Summary of production

Production by nation

Vehicles and ground weapons
Note: Number in parenthesis equals the number of tanks and self-propelled guns equipped with main weapons of 75 mm or larger. Smaller producing nations do not have this differentiation.

Soviet Union = 105,251 (92,595)
United States = 88,410 (71,067)
Germany = 46,857 (37,794)
United Kingdom = 27,896
Canada = 5,678
Japan = 2,515
Italy = 2,473
Hungary = 500 Tanks and self-propelled guns
Artillery includes anti-aircraft and anti-tank weapons with calibres above 37 mm.

Soviet Union = 516,648
United States = 257,390
Germany = 159,147
United Kingdom = 124,877
Japan = 13,350
Canada = 10,552
Italy = 7,200
Other Commonwealth = 5,215
Hungary = 447 Artillery

Soviet Union = 200,300
United States = 105,054
United Kingdom = 102,950
Germany = 73,484
Commonwealth = 46,014 Mortars (over 60 mm)
Machineguns do not include sub-machineguns, or machine guns used for arming aircraft.

United States = 2,679,840
Soviet Union = 1,477,400
Germany = 674,280
Japan = 380,000
United Kingdom = 297,336
Canada = 251,925
Other Commonwealth = 37,983
Hungary = 4,583 Machineguns

United States = 2,382,311
Canada = 815,729
United Kingdom = 480,943
Germany = 345,914
Soviet Union = 197,100
Japan = 165,945
Italy = 83,000 Military trucks

Aircraft

United States = 324,750
Germany = 189,307
Soviet Union = 157,261
United Kingdom = 131,549
Japan = 76,320
Canada = 16,431
Italy = 11,122
Other Commonwealth = 3,081
Hungary = 1,046
Romania = 1,000 Military aircraft of all types

United States = 99,950
Soviet Union = 63,087
Germany = 55,727
United Kingdom = 49,422
Japan = 30,447
Italy = 4,510 Fighter aircraft

Soviet Union = 37,549
Germany = 12,539 Attack aircraft

United States = 97,810
United Kingdom = 34,689
Soviet Union = 21,116
Germany = 18,235
Japan = 15,117
Italy = 2,063 Bomber aircraft

Germany = 6,299
Japan = 5,654
United Kingdom = 3,967
United States = 3,918
Italy = 1,080 Reconnaissance aircraft

United States = 23,929
Soviet Union = 17,332
Germany = 3,079
Japan = 2,110
United Kingdom = 1,784
Italy = 468 Transport aircraft

United States = 57,623
United Kingdom = 31,864
Japan = 15,201
Germany = 11,546
Soviet Union = 4,061
Italy = 1,769 Training aircraft

Naval ships
Figure in parentheses indicates merchant vessels converted to Escort carriers.

United States = 22 (141)
Japan = 16
United Kingdom = 14
Germany = 0 None completed by the end of the war. Aircraft carriers

United States = 8
United Kingdom = 5
Italy = 3
Japan = 2
Germany = 2 Battleships

United States = 48
United Kingdom = 32
Japan = 9
Italy = 6
Soviet Union = 2 Cruisers

United States = 349
United Kingdom = 240
Japan = 63
Soviet Union = 25
Germany = 17
Italy = 6 Destroyers

United States = 498
United Kingdom = 413
Canada = 191
Germany = 23 Convoy escorts

Germany = 1,337
United States = 422
Japan = 167
United Kingdom = 167
Soviet Union = 52
Italy = 28 Submarines

United States = 33,993,230
United Kingdom = 6,378,899
Japan = 4,152,361
Commonwealth = 2,702,943
Italy = 469,606 Merchant tonnage

Materials
In millions of metric tons

Germany = 2,420.3
United States = 2,149.7
United Kingdom = 1,441.2
Soviet Union = 590.8
Japan = 184.5
Canada = 101.9
Italy = 16.9
Hungary = 6.6
Romania = 1.6 Coal
In millions of metric tons

United States = 396.9
Germany = 240.7
United Kingdom = 119.3
Soviet Union = 71.3
Japan = 21.0
Hungary = 14.1
Romania = 10.8
Italy = 4.4
Canada = 3.6 Crude Oil

GDP values: Harrison, Mark, "The Economics of World War II: Six Great Powers in International Comparison", Cambridge University Press (1998).
Milward, Alan S., "War, economy, and society, 1939-1945", University of California Press (1979).
Overy, Richard, "Why the Allies Won (Paperback)", W. W. Norton & Company; Reprint edition (1997).
Barnett, Correlli, "The audit of war : the illusion & reality of Britain as a great nation", Macmillan, (1986).

For information about chromosomes in genetic algorithms, see chromosome (genetic algorithm).
A chromosome is a single large macromolecule of DNA, and constitutes a physically organized form of DNA in a cell. It is a very long, continuous piece of DNA (a single DNA molecule), which contains many genes, regulatory elements and other intervening nucleotide sequences. A broader definition of "chromosome" also includes the DNA-bound proteins which serve to package and manage the DNA. The word chromosome comes from the Greek χρῶμα (chroma, color) and σῶμα (soma, body) due to its capacity to be stained very strongly with vital and supravital dyes.
Chromosomes vary extensively between different organisms. The DNA molecule may be circular or linear, and can contain anything from tens of kilobase pairs to hundreds of megabase pairs. Typically eukaryotic cells (cells with nuclei) have large linear chromosomes and prokaryotic cells (cells without nuclei) smaller circular chromosomes, although there are many exceptions to this rule. Furthermore, cells may contain more than one type of chromosome; for example mitochondria in most eukaryotes and chloroplasts in plants have their own small chromosome in addition to the nuclear chromosomes.
In eukaryotes nuclear chromosomes are packaged by proteins (particularly histones) into chromatin to fit the massive molecules into the nucleus. The structure of chromatin varies through the cell cycle, and is responsible for the compaction of DNA into the classic four-arm structure during mitosis and meiosis. Prokaryotes do not form chromatin, because the cells lack proteins required and the circular configuration of the molecule prevents this.
"Chromosome" is a rather loosely defined term. In prokaryotes, a small circular DNA molecule may be called either a plasmid or a small chromosome. In viruses, mitochondria, and chloroplasts their DNA molecules are commonly referred to as chromosomes, despite being naked molecules, as they constitute the complete genome of the organism or organelle.

History
Eukaryotes (cells with nuclei such as plants, yeast, and animals) possess multiple large linear chromosomes contained in the cell's nucleus. Each chromosome has one centromere, with one or two arms projecting from the centromere, although under most circumstances these arms are not visible as such. In addition most eukaryotes have a small circular mitochondrial genome, and some eukaryotes may have additional small circular or linear cytoplasmic chromosomes.
In the nuclear chromosomes of eukaryotes, the uncondensed DNA exists in a semi-ordered structure, where it is wrapped around histones (structural proteins), forming a composite material called chromatin.

Chromosomes in eukaryotes

Main article: Chromatin Chromatin
During interphase (the period of the cell cycle where the cell is not dividing) two types of chromatin can be distinguished:
Individual chromosomes cannot be distinguished at this stage - they appear in the nucleus as a homogeneous tangled mix of DNA and protein.

Euchromatin, which consists of DNA that is active, e.g., expressed as protein.
Heterochromatin, which consists of mostly inactive DNA. It seems to serve structural purposes during the chromosomal stages. Heterochromatin can be further distinguished into two types:

• Constitutive heterochromatin, which is never expressed. It is located around the centromere and usually contains repetitive sequences.
  Facultative heterochromatin, which is sometimes expressed. Interphase chromatin
  See also: mitosis and meiosis
  In the early stages of mitosis or meiosis (cell division), the chromatin strands become more and more condensed. They cease to function as accessible genetic material (transcription stops) and become a compact transportable form. This compact form makes the individual chromosomes visible, and they form the classic four arm structure, a pair of sister chromatids attached to each other at the centromere. The shorter arms are called p arms (from the French petit, small) and the longer arms are called q arms (q follows p in the Latin alphabet). This is the only natural context in which individual chromosomes are visible with an optical microscope.
  During divisions long microtubules attach to the centromere and the two opposite ends of the cell. The microtubules then pull the chromatids apart, so that each daughter cell inherits one set of chromatids. Once the cells have divided, the chromatids are uncoiled and can function again as chromatin. In spite of their appearance, chromosomes are structurally highly condensed which enables these giant DNA structures to be contained within a cell nucleus (Fig. 2).
  The self assembled microtubules form the spindle, which attaches to chromosomes at specialized structures called kinetochores, one of which is present on each sister chromatid. A special DNA base sequence in the region of the kinetochores provides, along with special proteins, longer-lasting attachment in this region.
  
  Metaphase chromatin and division
  Prokaryotes (eg. Bacteria) typically have a single circular chromosome, but many variations do exist. Bacterial DNA also exists as plasmids, essentially miniature chromosomes, which are small circular pieces of DNA that are readily transmitted between bacteria. The distinction between plasmids and chromosomes is poorly defined, though size and necessity are generally taken into account.
  
  Chromosomes in prokaryotes
  Prokaryotes chromosomes have less sequence-based structure than eukaryotes. They do, however, typically have a single point, the origin of replication, from which replication starts.
  The genes in prokaryotes are often organised in operons, and do not contain introns, unlike eukaryotes.
  
  Structure in sequences
  Bacterial chromosomes tend to be tethered to the plasma membrane of the bacteria. In molecular biology application, this allows for its isolation from plasmid DNA by centrifugation of lysed bacteria and pelleting of the membranes (and the attached DNA).
  
  Location in the cell
  Prokaryotes do not possess histones or nuclei, and so do not possess chromatin like eukaryotes. There is, however, thought to be some structural organisation to help condense the large molecule into the small prokaryotic cell.
  Prokaryotic chromosomes and plasmids are, like eukaryotic DNA, generally supercoiled. The DNA must first be released into its relaxed state for access for transcription, regulation, and replication.
  
  DNA packaging
  
  Eukaryotes
  Prokaryote species generally have one copy of each major chromosome, but most cells can easily survive with multiple copies. Plasmids and plasmid-like small chromosomes are, like in eukaryotes, very variable in copy number. The number of plasmids in the cell is almost entirely determined by the rate of division of the plasmid - fast division causes high copy number, and vice versa.
  Prokaryotes
  
  
  Main article: Karyotype Karyotype
  
  

  Main articles: Chromosome abnormalities and aneuploidy Human chromosomes
  
  Locus (explains gene location nomenclature)
  Sex-determination system
  

  
  
  • XY sex-determination system
    
    
    
    • X chromosome
      
      
      
      • X-inactivation
        Y chromosome
        
        
        
        • Y-chromosomal Adam
          Y-chromosomal Aaron
          Genetic genealogy
          
          
          
          • Genealogical DNA test
            Genetic deletion
            List of number of chromosomes of various organisms

Michele Angelo Besso (Riesbach, May 25, 1873 – March 15, 1955 in Genova) was a Swiss/Italian engineer, and a close friend of Albert Einstein during his years at the Federal Polytechnic Institute in Zurich Einstein called Besso "the best sounding board in Europe" for scientific ideas.

Einstein and Besso: the Eagle and the Sparrow
Einstein's historic 1905 paper "On the Electrodynamics of Moving Bodies" in which the theory now known as special relativity was announced, was unusual for a scientific paper in that it carried none of the usual references to the literature of theoretical physics. The only individual credited with any contribution to the 1905 paper was Michele Angelo Besso, whom Einstein thanked for "many useful suggestions." Besso, whom Einstein once characterized as a perpetual student, had studied mechanical engineering at the Zurich Polytechnic during the years Einstein was enrolled in the physics section. The two met at a musical evening in Zurich and remained lifelong friends. Einstein had been boarding with the Winteler family in Switerland. The Winteler's daughter, Marie, was Einstein's first love; Einstein's sister Maja would eventually marry Winteler's son Paul; and his close friend Michele Besso would marry their eldest daughter, Anna.
In 1904, on the recommendation of Einstein, Besso took a position at the Swiss Patent Office. Whenever they could, the two friends engaged in long discussions of physics and mathematics. Besso played a very important role as a "sounding board" for Einstein, and when Einstein moved to Zurich and later Berlin, the two men visited and kept up a lively correspondence. When, shortly after taking up his position in Berlin in 1914, Einstein sent his wife Mileva and his sons Hans-Albert and Eduard back to Zurich, Besso and his wife, Anna Besso-Winteler, took on the role of intermediary between the feuding partners as their marriage was dissolving. They even cared for the couple's two sons during Mileva's illness. In 1913, when Einstein and Besso collaborated on the calculations in the manuscript under discussion here, Besso was living in Gorizia, near Trieste. The manuscript shows that in this case Besso functioned as considerably more than just a sounding board. Although he left the hardest parts to Einstein, he did take responsibility for some important parts of the calculations. In later years, Besso described his scientific collaboration with Einstein with a charming simile: Einstein was an eagle, and he, Besso, a sparrow. Under the eagle's wing, the sparrow had been able to fly higher than on its own.
Toward the end of his life, Einstein got a letter from the wife of his friend Michele Besso, who stayed in Switzerland. And she said, "You know, you and Michele were friends in Bern, and Michele is so talented, how come he never accomplished anything?" And Einstein said, "But of course, it's because he's a good man!" Einstein considered that his two marriages had been failures and looked at Michele Besso with his wife, and saw that they were very much in love.
Besso was of Jewish Italian (Sephardi) descent.

Sir Chandrasekhara Venkata Raman, CBE (Tamil: சந்திரசேகர வெங்கடராமன்) (7 November 1888 – 21 November 1970) was an Indian physicist, who was awarded the 1930 Nobel Prize in Physics for his work on the scattering of light and for the discovery of the Raman effect, which is named after him.

Biography
Chandrasekhara Venkata Raman was born on November 7, 1888 in Tiruchinapalli, Tamil Nadu. He was the second child of Chandrasekhar Iyer and Parvathi Amma. His father was a lecturer in mathematics and physics, so he had an academic atmosphere at home.

Early years
He completed his BA and MA in Physics from the Presidency College, Madras . He entered Presidency College, Madras, in 1902, and in 1904 passed his B.A. examination, winning the first place and the gold medal in physics; in 1907 he gained his M.A. degree, obtaining the highest distinctions. He joined the Indian Finance Department as an Assistant Accountant General in Calcutta. As the story goes, one evening while returning from work, he spotted the sign of the Indian Association for the Cultivation of Science. He started visiting the laboratory after office hours and did experiments, which culminated with his Nobel Prize winning work.
In 1917, Raman resigned from his government service and took up the newly created Palit Professorship in Physics at the University of Calcutta. Simultaneously, he continued doing research at the IACS, where he became the Honorary Secretary. Raman used to refer to this period as the golden era of his career. Many talented students gathered around him at the IACS and the University of Calcutta. He was president of the 16th session of the Indian Science Congress in 1929.
Raman won the 1930 Nobel Prize in Physics for his work on the scattering of light and for the discovery of the Raman effect. Raman spectroscopy is based on this phenomenon. An interesting anecdote goes that he booked his tickets to Stockholm several months before the Nobel prizes were announced.
Raman also worked on the acoustics of musical instruments. He worked out the theory of transverse vibration of bowed strings, on the basis of superposition velocities. This does a better job in explaining bowed string vibration over Helmholtz's approach. He was also the first to investigate the harmonic nature of the sound of the Indian drums such as the tabla and the mridangam.
In 1934, Raman became the director of the newly established Indian Institute of Science in Bangalore, where two years later he continued as a professor of physics. In 1947, he was appointed as the first National Professor by the new government of Independent India.
He also started a company called Travancore Chemical and Manufacturing Co. Ltd. in 1943 along with Dr. Krishnamurthy. The Company during its 60 year history, established 4 factories in Southern India. [1]
He was knighted in 1929 and awarded the Bharat Ratna in 1954. Raman was also awarded the Lenin Peace Prize (1957).
CV Raman is the uncle of three world renowned Physicists Subrahmanyan Chandrasekhar Nobel laureate, Sivaramakrishna Chandrasekhar FRS, known for Liquid crystal research and Sivaraj Ramaseshan, ex director of Indian Institute of Science.
India celebrates National Science Day on the 28th February of every year to commemorate Raman's discovery in 1928.

Middle years
He retired from the Indian Institute of Science in 1948 and a year later he established the Raman Research Institute in Bangalore Karnataka, serving as its director and remained active there until his death in 1970, in Bangalore, Karnataka, at the age of 82.

Later years

Quotes
For compact work, see: Scientific Papers of CV Raman, Ed. S Ramaseshan, Indian Academy of Sciences, Bangalore 1988.

Vol. 1 - Scattering of Light (Ed. S Ramaseshan)
Vol. 2 - Acoustic
Vol. 3 - Optica
Vol. 4 - Optics of Minerals and Diamond
Vol. 5 - Physics of Crystals
Vol. 6 - Floral Colours and Visual Perception
Vol, 7 - Bibliography

Raman laser
Raman scattering
Raman spectroscopy
Raman amplification
Resonance Raman spectroscopy
Raman Research Institute
Raman optical activity
Raman (crater)

Holopaw, Florida is a small town in Osceola County, Florida. It is located at the eastern end of the multiplex of highways US 192 and US 441. It has a population of fewer than 5000 people.
As with many towns in Florida, it was used for military training during World War II. The remnants of a landing field can still be seen today by a stand of trees, about 1 mile east of town.
The community name derives from Indian term for "place where something is hauled". It is in the Eastern Standard time zone. Elevation is 75 feet.
The latitude of Holopaw is 28.135N. The longitude is -81.076W.

Listed below are the Major League Baseball players who have hit 30 or more home runs before the All-Star Game break. There were no MLB All-Star games prior to 1933, as the All-Star game is not played exactly at mid-season but about 90 games in (the full season is 162 games).

The list
This list is sorted chronologically. Multiple occurrences are denoted in parentheses.
* The 1994 season was shortened due to MLB players strike.  

Ballingry Rovers F.C. are a Scottish junior football club based in Glencraig, Fife. Their home ground is Ore Park.
The SJFA restructured prior to the 2006/7 season, and Rovers found themselves in the twelve-team East Region, Central Division. They finished third in their first season in the division.

Assault is a crime of violence against another person. In some jurisdictions, including Australia and New Zealand assault refers to an act that causes another to apprehend immediate and personal violence, while in other jurisdictions, such as the United States, assault refers only to the threat of violence caused by an immediate show of force. Simple assaults that do not involve any aggravation such as use of a deadly weapon are distinguished from aggravated assaults in some juridictions.
Assault is often defined to include not only violence, but any physical contact with another person without their consent. In Common Law jurisdictions, including England and Wales and the USA, battery is the crime that represents the unlawful physical contact, though this distinction does not exist in all jurisdictions. Exceptions exist to cover unsolicited physical contact which amount to normal social behavior (for example, patting someone on the back): see (in England and Wales) Collins v. Wilcox[1984] 3 All ER 374.
In most jurisdictions, the intention to cause grievous bodily harm (or its equivalent) may amount to the mental requirement to prefer a charge of murder in circumstances where the harm inflicted upon the victim proves fatal. In England and Wales, this fact was criticised by Lord Edmund-Davies in Cunningham [1982] AC 566.

American jurisprudence
Aggravated assault is, in some jurisdictions, a stronger form of assault, usually using a deadly weapon. A person has committed an aggravated assault when that person:
Aggravated assault is usually differentiated from simple assault by the offender's intent (i.e., to murder, to rape etc.), the extent of the injury to the victim, or the use of a deadly weapon, although legal definitions vary between jurisdictions. Sentences for aggravated assault are generally more severe, reflecting the greater degree of harm or malice intended by the perpetrator.

attempts to cause serious bodily injury to another person; or
causes such injury purposely, knowingly, or recklessly in circumstances where the person has exhibited indifference to human life; or
attempts or causes bodily injury to another person with a deadly weapon. Aggravated assault
Although the range and precise application of defenses varies between jurisdictions, the following represents a list of the defenses that may apply to all levels of assault:

General defenses to assaults
Consent may be a complete or partial defense to assault. In some jurisdictions, most notably England, it is not a defense where the degree of injury is severe, as long as there is no legally recognised good reason for the assault.. This can have important consequences when dealing with issues such as consensual sadomasochistic sexual activity, the most notable case being the Operation Spanner case. Legally recognised good reasons for consent include; surgery, activities within the rules of a game (Burnes), bodily adornment (R v Wilson), or horseplay (Jones and others). However, any activity outside the rules of the game is not legally recognised as a defence of consent.

Consent
Police officers and court officials have a general power to use force for the purpose of effecting an arrest or generally carrying out their official duties. Thus, a court officer taking possession of goods under a court order may use force if reasonably necessary. However in Scottish Law, consent is not a defense for assault.

Arrest and other official acts
In some jurisdictions, caning and other forms of corporal punishment are a part of the culture. Evidently, if it is a state-administered punishment, e.g. as in Singapore, the officers who physically administer the punishment have immunity. Some states also permit the use of less severe punishment for children in school and at home by parents. In English law, s58 Children Act 2004, limits the availability of the lawful correction defense to common assault under s39 Criminal Justice Act 1988.

Punishment
Self defense and defense of others may be defenses to liability. They usually require that force was necessary and the degree of force was reasonable.

Self-defense
This may or may not involve self defense in that, using a reasonable degree of force to prevent another from committing a crime could involve preventing an assault, but it could be preventing a crime not involving the use of personal violence.

Prevention of crime
Some states allow force to be used in defense of property, to prevent damage either in its own right, or under one or both of the preceding classes of defense in that a threat or attempt to damage property might be considered a crime (in English law, under s5 Criminal Damage Act 1971 it may be argued that the defendant has a lawful excuse to damaging property during the defense and a defense under s3 Criminal Law Act 1967) subject to the need to deter vigilantes and excessive self-help.

Variations of Assault in England and Wales

Affray
Battery (crime)
Assault (tort)
Street fighting
Domestic violence
Gay-bashing
Hate crime
Mayhem
Misdemeanor
Offences Against The Person Act 1861
Terroristic Threats

Catherine Ségurane (Catarina Ségurana in the Niçard dialect of Provençal) is a folk heroine of the city of Nice, France who is said to have played a decisive role in repelling the city's siege by Turkish invaders allied with Francis I, the king of France, in the summer of 1543. At the time, Nice was part of Savoy, independent from France, and had no standing military to defend it. Most versions of the tale have Catherine Ségurane, a common washerwoman, leading the townspeople into battle. Legend has it that she knocked out a standard bearer with her beater and took his flag.
However, according to one commonly told story, Catherine took the lead in defending the city by standing before the invading forces and exposing her bare bottom. This is said to have so repulsed the Turkish infantry's Muslim sense of decency that they turned and fled. However, in Turkish culture, the practice of "mooning" is considered odd or absurdly immoral but never offensive and most probably as a sexual teasing, especially when performed by a female.
Catherine's existence has never been definitively proven, and her heroic act of mooning is likely pure fiction or highly exaggerated; Jean Badat, a historian who stood witness to the siege, made no mention of her involvement in the defense. Historically attested defense of Nice include the townspeople's destruction of a key bridge and the arrival of an army mustered by a Savoyard duke, Charles III. Nevertheless, the legend of Catherine Ségurane has excited the local imagination. Louis Andrioli wrote an epic poem about her in 1808, and a play dedicated to her story was written by Jean-Baptiste Toselli in 1878. In 1923, a bas-relief monument to Catherine was erected near the supposed location of her feat. In Nice, Catherine Segurane Day is celebrated annually, concurrent with St. Catherine's Day on November 25.

Early years
Using a telescope, she discovered "Miss Mitchell's Comet" (Comet 1847 VI, modern designation is C/1847 T1) in the autumn of 1847. Some years previously, King Frederick VI of Denmark had established gold medal prizes to each discoverer of a "telescopic comet" (too faint to be seen with the naked eye). The prize was to be awarded to the "first discoverer" of each such comet (note that comets are often independently discovered by more than one person). She duly won one of these prizes, and this gave her worldwide fame, since the only previous woman to discover a comet had been Caroline Herschel.
There was a temporary question of priority because Francesco de Vico had independently discovered the same comet two days later, but had reported it first; however, this was resolved in Mitchell's favor. The prize was awarded in 1848 by the new king Frederick VII.
Note: some biographical sources misinterpret the words "first discoverer of a telescopic comet" and report that she was the first person in history to discover a comet using a telescope. That is not the case.
She was the first professional woman astronomer in the United States, noted for her discovery that sunspots are whirling vertical cavities and not, as previously thought, clouds.

Comet discovery
She became the first woman member of the American Academy of Arts and Sciences in 1848 and of the American Association for the Advancement of Science in 1850. She later worked at the U.S. Nautical Almanac Office, calculating tables of positions of Venus, and traveled in Europe with Nathaniel Hawthorne and his family.
She became professor of astronomy at Vassar College in 1865, the first person (male or female) appointed to the faculty. She was also named as Director of the Vassar College Observatory. After teaching there for some time, she learned that despite her reputation and experience, her salary was less than that of many younger male professors. She insisted on a salary increase, and got it.

Career
In 1842, she left the Quaker faith and followed Unitarian principles. In protest against slavery, she stopped wearing clothes made of cotton. She was friends with various suffragists such as Elizabeth Cady Stanton and co-founded the American Association for the Advancement of Women.

Efforts
She died in June 28, 1889, at the age of 71, in Lynn, Massachusetts. She was buried in Lot 411, Prospect Hill Cemetery, Nantucket.

Online sources

Kendall, Phebe Mitchell. Maria Mitchell; Life, Letters and Journals. Boston: Lee & Shepard, 1896. (out of print; written by her niece)
M. W. Whitney, In Memoriam, (Poughkeepsie, N. Y., 1889)
M. K. Babbitt, Maria Mitchell as her students Knew her, (Poughkeepsie, N. Y., 1912)
Albers, Henry editor "Maria Mitchell, A Life in Journals and Letters" College Avenue Press, Clinton Corners, NY, 2001. (Henry Albers was the Fifth Maria Mitchell Professor of Astronomy at Vassar College.)

Standing stones, orthostats, liths or more commonly, megaliths because of their large and cumbersome size, are solitary stones set vertically in the ground and come in many different varieties. Where they appear in groups together, often in a circular formation, they are sometimes called megalithic monuments. Standing stones are found throughout the world with no known or documented history.
Standing stones are usually difficult to date but pottery found underneath some in Atlantic Europe connects them with the Beaker people; others in the region appear to be earlier or later however.

Frank Alexander Wetmore (June 18, 1886 – December 7, 1978) was an American ornithologist and avian paleontologist.
Wetmore was born at North Freedom, Wisconsin and studied at the University of Kansas. He later studied at George Washington University, receiving his masters degree and doctorate.
Wetmore began federal service in 1910, working for the Biological Survey of the Department of Agriculture.
In 1915, he researched the use of lead shot in causing death in waterfowl. His paleontological research led to his work on the fossil birds Palaeochenoides miocaenus and Nesotrochis debooyi.
In 1925 Wetmore was appointed assistant secretary of the Smithsonian Institution, becoming secretary between 1945 and 1952. In 1939 he was elected a Corresponding Member of the Royal Australasian Ornithologists Union
He wrote A Systematic Classification for the Birds of the World (1930, revised in 1951 and 1960). This Wetmore Order received widespread acceptance, remaining popular until the end of the twentieth century.
He died in Glen Echo, Maryland.
Several taxa of birds have been named in his honor, including the Cretaceous genus Alexornis and the tanagers Wetmorethraupis sterrhopteron and Buthraupis wetmorei.

Ministers:
and National Assembly
The Minister of National Education, Advanced Instruction, and Research (French: Ministre de l'Éducation nationale, de l'Enseignement supérieur et de la Recherche, or simply "Minister of National Education," as the title has changed no small number of times in the course of the Fifth Republic) is the French government cabinet member charged with running France's public educational system and with the supervision of agreements and authorizations for private teaching organizations.
The Ministry's headquarters is located in the 18th century Hôtel de Rochechouart on the rue de Grenelle in Paris.
Given that National Education is France's largest employer, and employs more than half of the French state civil servants, the position is traditionally a fairly strategic one. The current minister is Xavier Darcos.

Foreign Affairs
Interior
Finances
Defence
Justice
National Education
Culture
Agriculture
Health
Transportation, Public Works, Tourism, Sea
Environment
Social Affairs, Housing
Youth and Sports
Overseas France History
A governmental position overseeing public education was first created in France in 1802. Following the various regime changes in France in the first decades of the 19th century, the position changed official status and name a number of times before the position of Minister of Public Instruction was created in 1828. For much of its history, the position was combined with that of Minister of Public Worship, who dealt with issues related to the Roman Catholic Church, except in instances where the Minister of Public Instruction was a Protestant. The position has also occasionally been combined with Minister of Sports and Minister of Youth Affairs. In 1932, the office's title was changed to Minister of National Education, although it was briefly changed back in 1940-1941, and was renamed Minister of Education during the Presidency of Valéry Giscard d'Estaing (1974-1981).

The Executive Directory (in French Directoire exécutif), commonly known as the Directory (or Directoire) held executive power in France from November 2, 1795 until November 10, 1799: following the Convention and preceding the Consulate. Five Directors shared power. The period of this regime, commonly referred to as the Directoire era, constitutes the last stage of the French Revolution and precedes the coming of the Consulate, which, in turn, was followed by the First Empire.
The directory system of government was also used in several French-dominated regions of Italy; see Directory (political).

Initial Directors
With the establishment of the Directory, the Revolution might seem closed. The nation only desired rest and the healing of its many wounds. Those who wished to restore Louis XVIII of France and the ancien régime and those who would have renewed the Reign of Terror were insignificant in number. The possibility of foreign interference had vanished with the failure of the First Coalition. Nevertheless, the four years of the Directory were a time of arbitrary government and chronic disquiet. The late atrocities had made confidence or goodwill between parties impossible. The same instinct of self-preservation which had led the members of the Convention to claim so large a part in the new legislature and the whole of the Directory impelled them to keep their predominance.
As the majority of Frenchmen wanted to be rid of them, they could achieve their purpose only by extraordinary means. They habitually disregarded the terms of the constitution, and, when the elections went against them, appealed to the sword. They resolved to prolong the war as the best expedient for prolonging their power. They were thus driven to rely upon the armies, which also desired war and were becoming less and less civic in temper.
Other reasons influenced them in this direction. The finances had been so thoroughly ruined that the government could not have met its expenses without the plunder and the tribute of foreign countries. If peace were made, the armies would return home and the directors would have to face the exasperation of the rank-and-file who had lost their livelihood, as well as the ambition of generals who could, in a moment, brush them aside. Barras and Rewbell were notoriously corrupt themselves and screened corruption in others. The patronage of the directors was ill-bestowed, and the general maladministration heightened their unpopularity.
The constitutional party in the legislature desired a toleration of the nonjuring clergy, the repeal of the laws against the relatives of the émigrés, and some merciful discrimination toward the émigrés themselves. The directors baffled all such endeavours. On the other hand, the socialist conspiracy of Babeuf was easily quelled. Little was done to improve the finances, and the assignats continued to fall in value.

Unpopularity of the Directory
But the Directory was sustained by the military successes of the year 1796. Hoche again pacified La Vendée (See Revolt in the Vendée). Bonaparte's victories in Italy more than compensated for the reverses of Jourdan and Moreau in Germany. The king of Sardinia made peace in May 1796, ceding Nice and Savoy to the French Republic and consenting to receive French garrisons in his Piedmontese fortresses. By the Treaty of San Ildefonso, concluded in August, Spain became the ally of France. In October 1796 Naples made peace.
In 1797 Bonaparte finished the conquest of northern Italy and forced Austria to make the treaty of Campo Formio (October), whereby the emperor ceded Lombardy and the Austrian Netherlands to the French Republic in exchange for Venice and undertook to urge upon the Diet the surrender of the lands beyond the Rhine. Notwithstanding the victory of Cape St Vincent, the United Kingdom was brought into such extreme peril by the mutinies in the fleet that she offered to acknowledge the French conquest of the Netherlands and to restore the French colonies.
The selfishness of the three directors threw away this golden opportunity. In March and April, the election of a new third of the Councils had been held. It gave a majority to the constitutional party. Among the directors, the lot fell on Le Tourneur to retire, and he was succeeded by Barthélemy, an eminent diplomatist, who allied himself with Carnot. The political disabilities imposed upon the relatives of émigrés were repealed. Priests who would declare their submission to the Republic were restored to their rights as citizens. It seemed likely that peace would be made and that moderate men would gain power.

Military successes
Barras, Rewbell, and La Révellière-Lépeaux then sought help from the armies. Although Royalists formed but a petty fraction of the majority, they accused that fraction of seeking to restore monarchy and to undo the work of the Revolution. Hoche, then in command of the Army of Sambre-et-Meuse, visited Paris and sent troops. Bonaparte sent General Augereau, who executed the coup d'état of 18 Fructidor (4 September 1797).
The councils were purged, the elections in forty-nine departments were cancelled, and many deputies and other men of note were arrested. Some of them, including Barthélemy, were deported to Cayenne. Carnot made good his escape. The two vacant places in the Directory were filled by Merlin of Douai and Nicolas-Louis François de Neufchâteau. Then the government frankly returned to Jacobin methods. The law against the relatives of émigrés was reenacted, and military tribunals were established to condemn émigrés who should return to France.
The nonjuring priests were again persecuted. Many hundreds were either sent to Cayenne or imprisoned in the hulks of Re and Oleron. La Révelliére Lépeaux seized the opportunity to propagate his religion. Many churches were turned into Theophilanthropic temples. The government strained its power to secure the recognition of the décadi as the day of public worship and the non-observance of Sunday. Liberty of the press ceased. Newspapers were confiscated and journalists were deported wholesale. It was proposed to banish from France all members of the old noblesse. Although the proposal was dropped, they were all declared to be foreigners and were forced to obtain naturalisation if they would enjoy the rights of other citizens. A formal bankruptcy of the state, the cancelling of two-thirds of the interest on the public debt, crowned the misgovernment of this disastrous time.

18 Fructidor
In the spring of 1798, not only a new third of the legislature had to be chosen, but the places of the members expelled by the revolution of Fructidor had to be filled. The constitutional party had been rendered helpless, and the mass of the electors were indifferent. But among the Jacobins themselves, there had arisen an extreme party hostile to the directors. With the support of many who were not Jacobins but detested the government, it bade fair to gain a majority. Before the new deputies could take their seats, the directors forced through the councils the law of the 22nd Floréal, annulling or perverting the elections in thirty departments and excluding forty-eight deputies by name. Even this coup d'état did not secure harmony between the executive and the legislature. In the councils, the directors were loudly charged with corruption and misgovernment. The retirement of Francois of Neufchâteau and the choice of Treilhard as his successor (15 May 1798) made no difference in the position of the Directory.
While France was thus inwardly convulsed, its rulers were doubly bound to husband the national strength and practise moderation towards other states. Since December 1797, a congress had been sitting at Rastatt to regulate the future of Germany. That it should be brought to a successful conclusion was of the utmost import for France. But the directors were driven by self-interest to new adventures abroad. Bonaparte was resolved not to sink into obscurity, and the directors were anxious to keep him as far as possible from Paris; they therefore sanctioned the expedition to Egypt which deprived the Republic of its best army and most renowned captain. Coveting the treasures of Bern, the Directors sent Brune to invade Switzerland and remodel its constitution. In revenge for the murder of General Duphot (28 December 1797), they sent Berthier to invade the Papal States and erect the Roman Republic. They also occupied and virtually annexed Piedmont. In all these countries, they organised such an effective pillage that the French became universally hated.
As the armies were far below the strength required by the policy of unbounded conquest and rapine, the first permanent law of conscription was passed in the summer of 1798. The attempt to enforce it caused a revolt of the peasants in the Belgian departments. The priests were held responsible and some eight thousand were condemned to deportation en masse, although much the greater part escaped by the goodwill of the people. Few soldiers were obtained by the conscription, for the government was as weak as it was tyrannical.
Under these circumstances, Horatio Nelson's victory of Aboukir (1 August 1798), which gave the British full command of the Mediterranean and isolated Bonaparte in Egypt, was the signal for a second coalition. Naples, Austria, Russia and Turkey joined Great Britain against France. Ferdinand IV of Naples, rashly taking the offensive before his allies were ready, was defeated and forced to seek a refuge in Sicily.

1798
In January 1799, the French occupied Naples and set up the Parthenopaean Republic. But the consequent dispersion of their weak forces only exposed them to greater peril. At home, the Directory was in a most critical position. In the elections of April 1799, a large number of Jacobins gained seats. A little later Rewbell retired. It was imperative to fill his place with a man of ability and influence. The choice fell upon Sieyès, who had kept aloof from office and retained not only his immeasurable self-conceit but the respect of the public.
Sieyès felt that the Directory had bankrupted its own reputation, and he intended to do far more than merely serve as a member of a board. He hoped to concentrate power in his own hands, to bridle the Jacobins, and to remodel the constitution. With the help of Barras, he proceeded to rid himself of the other directors. An irregularity having emerged in Treilhard's election, he retired, and Gohier took his place (30 Prairial, 18 June 1799). Merlin of Douai and La Révellière Lépeaux were driven to resign in June 1799; Moulin and Ducos replaced them. The three new directors so lacked significance that they could give no trouble, but for the same reason they could give little service.
Such a government proved ill-fitted to cope with the dangers then gathering round France. The directors having resolved on a French offensive in Germany, the French crossed the Rhine early in March, but the Archduke Charles of Austria defeated them at Stockach on 25 March 1799. The congress at Rastatt, which had sat for fifteen months without doing anything, broke up in April, and Austrian hussars murdered the French envoys. In Italy, the allies took the offensive with an army partly Austrian, partly Russian, under the command of the Russian field marshal (future generalissimo) Suvorov. After defeating Moreau at Cassano d'Adda on 27 April 1799, he occupied Milan and Turin. The puppet republics established by the French in Italy collapsed, and Suvorov defeated the French army on the Trebbia as it retreated from Naples.
Thus threatened with invasion on her German and Italian frontiers, France seemed disabled by anarchy within. The finances stood in the last distress; the anti-religious policy of the government kept many départements on the verge of revolt; and commerce almost ground to a halt due to the decay of roads and the increase of bandits. The French lacked any real political freedom, yet also lacked the ease or security which enlightened despotism can bestow. The Terrorists lifted their heads in the Council of Five Hundred. A Law of Hostages, which was really a new Law of Suspects, and a progressive income tax showed the temper of the majority. The Jacobin Club re-opened and became once more the focus of disorder. The Jacobin press renewed the licence of Hébert and Marat. Never since the outbreak of the Revolution had the public temper seemed so gloomy.
In this extremity, Sieyès chose as minister of police the old Terrorist Joseph Fouché, who best understood how to deal with his brethren. Fouché closed the Jacobin Club and deported a number of journalists. But, like his predecessors, Sieyès felt that for the revolution which he meditated he must have the help of a soldier. As his man of action, he chose General Joubert, one of the most distinguished among French officers. The Directory sent Joubert to restore the fortunes of the war in Italy. At Novi, on 15 August 1799, he encountered Suvorov. He was killed at the outset of the battle and his men suffered defeat.
After this disaster, the French held scarcely any territory south of the Alps save Genoa. The Russian and Austrian governments then agreed to drive the enemy out of Switzerland and to invade France from the east. At the same time, the joint forces of Great Britain and Russia assailed the Netherlands. But the narrow views and conflicting interests of the members of the second coalition doomed it to failure like the first. Lack of co-ordination between Austrians and Russians, and André Masséna's victory at Zürich (25 - 26 September 1799) stalled the invasion of Switzerland. In October the British and the Russians had to evacuate the Netherlands. All immediate danger to France ended, but the issue of the war remained in suspense. The Directors had felt forced to recall Bonaparte from Egypt. He anticipated their order and on 9 October 1799 landed at Fréjus.

1799

Main article: 18 Brumaire List of Directeurs

Timeline of the French Revolution
Directoire fashion

The voiceless glottal transition, commonly called a "fricative", is a type of sound used in some spoken languages which often behaves like a consonant, but sometimes behaves more like a vowel, or is indeterminate in its behavior. The symbol in the International Phonetic Alphabet that represents this sound is h, and the equivalent X-SAMPA symbol is h. People lacking this sound in their native language often have difficulty trying to produce it. Notably, speakers of French.

In English

Arabic: هدهد [ˈhudhud], "hoopoe"
Avar: гьа [ha], "oath"
Lower Navarrese Basque: hirur, [hiɾuɾ], "three"
Chechen: хIара, [hara], "this"
Coptic: ϩⲣⲁ [hra], "face"
Dutch: hebben [hɛbə], "to have"
Faeroese: Hon, [hoːn], "she"
Finnish: hammas [hɑmːɑs], "tooth"
German: haben [haːbn̩], "to have"
Hungarian: helyes [hɛjɛʃ], "right"
Kabardian: тхылъхэ, [tχɪɬhɑ], "books"
Lao: ຫ້າ [haː˧˩], "five"
Pashto: ﻫﻮ [ho], "yes"
Persian: هفت [hæft], "seven"
Piraha: hi [hì], "he"
Romanian: hăţ [həʦ], "bridle"
Caribbean Spanish: José [hoˈse], "Joseph"
Thai: ห้า [haː˥˩], "five"
Turkish: halı [hɑ̟ˡɫɨ], "carpet"
Ubykh: [dwaha], "prayer"
Vietnamese: hát [hɐːt̚˧˥], "to sing"

A volcano is an opening, or rupture, in the Earth's surface or crust, which allows hot, molten rock, ash and gases to escape from deep below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.
Volcanoes are generally found where tectonic plates pull apart or are coming together. A mid-oceanic ridge, like the Mid-Atlantic Ridge, has examples of volcanoes caused by "divergent tectonic plates" pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by "convergent tectonic plates" coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching of the Earth's crust and where the crust grows thin (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the European Rhine Graben with its Eifel volcanoes, the Wells Gray-Clearwater Volcanic Field and the Rio Grande Rift in North America.
Finally, volcanoes can be caused by "mantle plumes", so-called "hotspots"; these hotspots can occur far from plate boundaries, such as the Hawaiian Islands. Interestingly, hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons.

Locations
At the mid-oceanic ridges, two tectonic plates diverge from one another. New oceanic crust is being formed by hot molten rock slowly cooling down and solidifying. In these places, the crust is very thin due to the pull of the tectonic plates. The release of pressure due to the thinning of the crust leads to adiabatic expansion, and the partial melting of the mantle. This melt causes the volcanism and make the new oceanic crust. The main part of the mid-oceanic ridges are at the bottom of the ocean, and most volcanic activity is submarine. Black smokers are a typical example of this kind of volcanic activity. Where the mid-oceanic ridge comes above sea-level, volcanoes like the Hekla on Iceland are formed. Divergent plate boundaries create new seafloor and volcanic islands.

Convergent plate boundaries
Hotspots are not located on the ridges of tectonic plates, but on top of mantle plumes, where the convection of Earth's mantle creates a column of hot material that rises until it reaches the crust, which tends to be thinner than in other areas of the Earth. The temperature of the plume causes the crust to melt and form pipes, which can vent magma. Because the tectonic plates move whereas the mantle plume remains in the same place, each volcano becomes dormant after a while and a new volcano is then formed as the plate shifts over the hotspot. The Hawaiian Islands are thought to be formed in such a manner, as well as the Snake River Plain, with the Yellowstone Caldera being the current part of the North American plate over the hotspot.

Hotspots
The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater in its top. This describes just one of many types of volcano, and the features of volcanoes are much more complicated. The structure and behavior of volcanoes depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater, whereas others present landscape features such as massive plateaus. Vents that issue volcanic material (lava, which is what magma is called once it has broken the surface, and ash) and gases (mainly steam and magmatic gases) can be located anywhere on the landform. Many of these vents give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Hawaii's Kīlauea.
Other types of volcanoes include cryovolcanos (or ice volcanoes), particularly on some moons of Jupiter, Saturn and Neptune; and mud volcanoes, which are formations often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes, except when a mud volcano is actually a vent of an igneous volcano.
Volcanic features
Main article: Shield volcano
Hawaii and Iceland are examples of places where volcanoes extrude huge quantities of basaltic lava that gradually build a wide mountain with a shield-like profile. Their lava flows are generally very hot and very fluid, contributing to long flows. The largest lava shield on Earth, Mauna Loa, rises over 9,000 m from the ocean floor, is 120 km in diameter and forms part of the Big Island of Hawaii, along with other shield volcanoes such as Mauna Kea and Kīlauea. Olympus Mons is the largest shield volcano on Mars, and is the tallest known mountain in the solar system. Smaller versions of shield volcanoes include lava cones, and lava mounds.
Quiet eruptions spread out basaltic lava in flat layers. The buildup of these layers form a broad volcano with gently sloping sides called a shield volcano. Examples of shield volcanoes are the Hawaiian Islands.

Shield volcanoes

Main article: Volcanic cone Cinder cones

Main article: Stratovolcano Stratovolcanoes

Main article: Supervolcano Super volcanoes

Main article: Submarine volcano Submarine volcanoes

Main article: Subglacial volcano Subglacial volcanoes

Erupted material
Another way of classifying volcanoes is by the composition of material erupted (lava), since this affects the shape of the volcano. Lava can be broadly classified into 4 different compositions (Cas & Wright, 1987):

If the erupted magma contains a high percentage (>63%) of silica, the lava is called felsic.

• Felsic lavas (or rhyolites) tend to be highly viscous (not very fluid) and are erupted as domes or short, stubby flows. Viscous lavas tend to form stratovolcanoes or lava domes. Lassen Peak in California is an example of a volcano formed from felsic lava and is actually a large lava dome.
  Because siliceous magmas are so viscous, they tend to trap volatiles (gases) that are present, which cause the magma to erupt catastrophically, eventually forming stratovolcanoes. Pyroclastic flows (ignimbrites) are highly hazardous products of such volcanoes, since they are composed of molten volcanic ash too heavy to go up into the atmosphere, so they hug the volcano's slopes and travel far from their vents during large eruptions. Temperatures as high as 1,200 °C are known to occur in pyroclastic flows, which will incinerate everything flammable in their path and thick layers of hot pyroclastic flow deposits can be laid down, often up to many meters thick. Alaska's Valley of Ten Thousand Smokes, formed by the eruption of Novarupta near Katmai in 1912, is an example of a thick pyroclastic flow or ignimbrite deposit. Volcanic ash that is light enough to be erupted high into the Earth's atmosphere may travel many kilometres before it falls back to ground as a tuff.
  If the erupted magma contains 52-63% silica, the lava is of intermediate composition.
  
  
  
  • These "andesitic" volcanoes generally only occur above subduction zones (e.g. Mount Merapi in Indonesia).
    If the erupted magma contains <52% and >45% silica, the lava is called mafic (because it contains higher percentages of magnesium (Mg) and iron (Fe)) or basaltic. These lavas are usually much less viscous than rhyolitic lavas, depending on their eruption temperature; they also tend to be hotter than felsic lavas. Mafic lavas occur in a wide range of settings:
    
    
    
    • At mid-ocean ridges, where two oceanic plates are pulling apart, basaltic lava erupts as pillows to fill the gap;
      Shield volcanoes (e.g. the Hawaiian Islands, including Mauna Loa and Kilauea), on both oceanic and continental crust;
      As continental flood basalts.
      Some erupted magmas contain <=45% silica and produce lava called ultramafic. Ultramafic flows, also known as komatiites, are very rare; indeed, very few have been erupted at the Earth's surface since the Proterozoic, when the planet's heat flow was higher. They are (or were) the hottest lavas, and probably more fluid than common mafic lavas. Lava composition
      Two types of lava are named according to the surface texture: ʻAʻa (pronounced IPA [ʔaʔa]) and pāhoehoe (pronounced [paːho͡eːho͡eː]), both words having Hawaiian origins. ʻAʻa is characterized by a rough, clinkery surface and is what most viscous and hot lava flows look like. However, even basaltic or mafic flows can be erupted as ʻaʻa flows, particularly if the eruption rate is high and the slope is steep. Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Usually, only mafic flows will erupt as pāhoehoe, since they often erupt at higher temperatures or have the proper chemical make-up to allow them to flow at a higher fluidity.
      
      Lava texture
      A popular way of classifying magmatic volcanoes goes by their frequency of eruption, with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes, which was explained above.
      There is no real consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of eruption. Given the long lifespan of such volcanoes, they are very active. By our lifespans, however, they are not. Complicating the definition are volcanoes that become restless (producing earthquakes, venting gasses, or other non-eruptive activities) but do not actually erupt.
      Scientists usually consider a volcano active if it is currently erupting or showing signs of unrest, such as unusual earthquake activity or significant new gas emissions. Many scientists also consider a volcano active if it has erupted in historic time. It is important to note that the span of recorded history differs from region to region; in the Mediterranean, recorded history reaches back more than 3,000 years but in the Pacific Northwest of the United States, it reaches back less than 300 years, and in Hawaii, little more than 200 years. The Smithsonian Global Volcanism Program's definition of 'active' is having erupted within the last 10,000 years.
      Dormant volcanoes are those that are not currently active (as defined above), but could become restless or erupt again. Confusion however, can arise because many volcanoes which scientists consider to be active are referred to as dormant by laypersons or in the media.
      Extinct volcanoes are those that scientists consider unlikely to erupt again. Whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct.
      For example, the Yellowstone Caldera in Yellowstone National Park is at least 2 million years old and hasn't erupted violently for approximately 640,000 years, although there has been some minor activity relatively recently, with hydrothermal eruptions less than 10,000 years ago and lava flows about 70,000 years ago. For this reason, scientists do not consider the Yellowstone Caldera extinct. In fact, because the caldera has frequent earthquakes, a very active geothermal system (i.e., the entirety of the geothermal activity found in Yellowstone National Park), and rapid rates of ground uplift, many scientists consider it to be an active volcano.
      
      Volcanic activity
      
      Notable volcanoes
      Main article: List of volcanoes
      The 16 current Decade Volcanoes are:
      
      
      
      
      
      
      

      Avachinsky-Koryaksky, Kamchatka, Russia Colima, Mexico Mount Etna, Italy Galeras, Colombia Mauna Loa, Hawaii, USA Merapi, Indonesia Nyiragongo, Democratic Republic of the Congo Mount Rainier, Washington, USA

      Sakurajima, Japan Santamaria/Santiaguito, Guatemala Santorini, Greece Taal Volcano, Philippines Teide, Canary Islands, Spain Ulawun, Papua New Guinea Mount Unzen, Japan Vesuvius, Italy

      
      
      
      Avachinsky-Koryaksky, Kamchatka, Russia
      Colima, Mexico
      Mount Etna, Italy
      Galeras, Colombia
      Mauna Loa, Hawaii, USA
      Merapi, Indonesia
      Nyiragongo, Democratic Republic of the Congo
      Mount Rainier, Washington, USA
      Sakurajima, Japan
      Santamaria/Santiaguito, Guatemala
      Santorini, Greece
      Taal Volcano, Philippines
      Teide, Canary Islands, Spain
      Ulawun, Papua New Guinea
      Mount Unzen, Japan
      Vesuvius, Italy On Earth
      The Earth's Moon has no large volcanoes and no current volcanic activity, although recent evidence suggests it may still possess a partially molten core. It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
      
      Elsewhere in the solar system
      There are many different kinds of volcanic activity and eruptions: phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity.
      The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulphur dioxide. Other principal volcanic gases include hydrogen sulphide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.
      Large, explosive volcanic eruptions inject water vapor (H₂O), carbon dioxide (CO₂), sulfur dioxide (SO₂), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 10-20 miles above the Earth's surface. The most significant impacts from these injections come from the conversion of sulphur dioxide to sulphuric acid (H₂SO₄), which condenses rapidly in the stratosphere to form fine sulfate aerosols. The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space - and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years. The sulphate aerosols also promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (ClO), which destroys ozone (O₃). As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance. Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles.
      Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year. Volcanic eruptions may inject aerosols into the Earth's atmosphere. Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it. Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water.
      
      Effects of volcanoes
      Volcano is thought to derive from Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn originates from Vulcan, the name of a god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology.
      The Roman name for the island Vulcano has contributed the word for volcano in most modern European languages.
      
      Etymology
      
      In culture
      Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. One early idea counter to this was Jesuit Athanasius Kircher (1602-1680), who witnessed eruptions of Aetna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal.
      Various explanations were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface.
      
      Past beliefs
      The volcano appears as a charge in heraldry.
      
      Heraldry
      
      Panoramas
      Lists
      Specific locations
      People
      
      History of Volcanology
      Plinian eruption
      Types of volcanic eruptions
      Predicting Volcanoes
      Volcano observatory
      Geomorphology
      Earth science
      Volcanic field
      Volcanic gas
      Tsunami
      List of volcanoes
      
      
      
      • List of terrestrial volcanoes
        List of extraterrestrial volcanoes
        List of famous volcanic eruption deaths
        Volcanic Explosivity Index (includes list of large eruptions)
        Types of volcanic eruptions
        List of deadliest natural disasters
        Iceland hotspot
        Pacific Ring of Fire
        Io (moon)
        Triton (moon)
        Category Volcanologists Further reading