Atto (symbol a) is a unit prefix in the metric system denoting a factor of 10−18 or 0.000000000000000001.

The unit multiple was adopted at the 12th General Conference on Weights and Measures (CGPM) in Resolution 8.[1] It is derived from the Danish word atten, meaning "eighteen".

Examples of its use:

Prefix Base 1000 Base 10 Decimal English word Adoption[nb 1]
Name Symbol Short scale Long scale
yotta Y  10008  1024 1000000000000000000000000  septillion  quadrillion 1991
zetta Z  10007  1021 1000000000000000000000  sextillion  trilliard 1991
exa E  10006  1018 1000000000000000000  quintillion  trillion 1975
peta P  10005  1015 1000000000000000  quadrillion  billiard 1975
tera T  10004  1012 1000000000000  trillion  billion 1960
giga G  10003  109 1000000000  billion  milliard 1960
mega M  10002  106 1000000  million 1873
kilo k  10001  103 1000  thousand 1795
hecto h  10002/3  102 100  hundred 1795
deca da  10001/3  101 10  ten 1795
 10000  100 1  one
deci d  1000−1/3  10−1 0.1  tenth 1795
centi c  1000−2/3   10−2 0.01  hundredth 1795
milli m  1000−1  10−3 0.001  thousandth 1795
micro μ  1000−2  10−6 0.000001  millionth 1873
nano n  1000−3  10−9 0.000000001  billionth  milliardth 1960
pico p  1000−4  10−12 0.000000000001  trillionth  billionth 1960
femto f  1000−5  10−15 0.000000000000001  quadrillionth  billiardth (Proposed) 1964
atto a  1000−6  10−18 0.000000000000000001  quintillionth  trillionth 1964
zepto z  1000−7  10−21 0.000000000000000000001  sextillionth  trilliardth 1991
yocto y  1000−8  10−24  0.000000000000000000000001  septillionth  quadrillionth 1991
  1. ^ Prefixes adopted before 1960 already existed before SI. 1873 was the introduction of the CGS system.


  1. ^ International Bureau of Weights and Measures (2006), The International System of Units (SI) (PDF) (8th ed.), ISBN 92-822-2213-6, archived (PDF) from the original on 2017-08-14
ATTO Technology

ATTO Technology, Inc. is a manufacturer of storage connectivity products for data-intensive computing. ATTO manufactures Fibre Channel and SAS/SATA host bus adapters, RAID adapters, Fibre Channel switches, protocol conversion bridges, storage controllers, MacOS iSCSI initiator software and acceleration software with storage interface connectivity to SATA, SAS, Fibre Channel, Thunderbolt devices, Ethernet and NVMe.

Adalbert Atto of Canossa

Adalbert Atto (or Adalberto Azzo) (died 13 February 988) was the first Count of Canossa and founder of that noble house which eventually was to play a determinant role in the political settling of Italy and the Investiture Controversy in the eleventh and twelfth centuries.

Adalbert first appears in sources as a son of Sigifred of Lucca. He was originally a vassal of King Lothair II and a miles of Adelard, Bishop of Reggio. He rose to prominence rapidly by sheltering Queen Adelaide in his castle at Canossa after she fled from the castle of Garda (951), where Berengar II had imprisoned her.

In 958, Adelaide made him a count sine re, that is, without an exclusive jurisdiction of right of inheritance. He did not appear again as a count in documents until December 961, during Berengar's ascendancy. On 20 April 962, he appeared as count of Reggio and Modena (comes Regensis sive Mutinensis). These appointments were probably a further product of his support for Adelaide and her new husband, Otto I of Germany. With the queen, he negotiated a division of power with the bishop of Reggio whereby the bishop was confirmed as comes civitatis, count of the city, and Adalbert as comes comitatus, count of the county, where the county was said to begin three or four miles outside the city walls. He appears with a similar title, comes comitatus Mantuanensis, in Mantua in a letter of the abbess of Santa Giulia dated 10 June 977.

In 984, Adalbert appears as a margrave. When Henry II, Duke of Bavaria, was acclaimed as king that year, he united Parma, Piacenza, Bergamo, Cremona, and Brescia to Adalbert's territories. However, Henry's usurpation of the throne was brief.

Adalbert Atto built a monastery at Canossa in 961, dedicated to S. Apollonio in 971. He also built a monastery at Brescello. He and his family were all buried in S. Apollonio.

Adalbert married the Supponid Hildegard (Ildegarda) and had three sons: Geoffrey; Tedald, who became respectively bishop (970) and count (1001) of Brescia; and Rudolph, who predeceased him. He had a daughter Prangarda who married Manfred I of Susa.


Adalimumab, sold under the brand name Humira among others, is a medication used to treat rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, ulcerative colitis, psoriasis, hidradenitis suppurativa, uveitis, and juvenile idiopathic arthritis. Use is generally only recommended in people who have not responded to other treatments. It is used by injection under the skin.Common side effects include upper respiratory tract infections, pain at the site of injection, rash, and headache. Other side effects may include serious infections, cancer, anaphylaxis, reactivation of hepatitis B, multiple sclerosis, heart failure, liver failure, and aplastic anemia. Use during pregnancy is not recommended, while some feel use during breastfeeding may be safe. Adalimumab is disease-modifying antirheumatic drug and monoclonal antibody that works by inactivating tumor necrosis factor-alpha (TNFα).Adalimumab was approved for medical use in the United States in 2002. A month supply in the United Kingdom costs the NHS about £704.28 as of 2018. In the United States the wholesale cost of this amount is about US$5,041.12. In 2014, a biosimilar came to market in India at a price of US$400 per month. While the patent expired in the United States in 2016 it may take a number of years before generic versions become avaliable there. In 2016 it was the 150th most prescribed medication in the United States with more than 4 million prescriptions.

Al Bano and Romina Power

Al Bano and Romina Power are an Italian pop music duo formed in 1975 by then-married couple Albano Carrisi and Romina Power. They were highly successful in Italy and mainland Europe throughout the 1980s and the early 1990s. Their best known international hits include "Felicità", "Sharazan", "Tu, soltanto tu (Mi hai fatto innamorare)", "Ci sarà", "Sempre sempre", and "Libertà!". The duo primarily recorded in Italian but have also released a great number of records in Spanish and French. They participated twice in Eurovision Song Contest to a moderate success and performed five times at Sanremo Music Festival, winning in 1984 with the song "Ci sarà". The couple also shot seven films, based on their songs, between 1967 and 1984. The two separated and divorced in 1999, but reunited professionally in 2013.

All My Friends Part 2

All My Friends Part 2 (Italian: Amici miei Atto II) is a 1982 Italian comedy film directed by Mario Monicelli. It is the sequel to Amici miei of 1975. The movie features Paolo Stoppa in one of his last roles. The last chapter of this saga is Amici miei - Atto III, directed by Nanni Loy (1985).

Amici miei – Atto III

Amici miei – Atto III (internationally released as My Friends Act III and All My Friends Part 3) is a 1985 Italian comedy film directed by Nanni Loy. It is the third chapter in the Amici Miei film series.For this film Gastone Moschin was awarded with a Silver Ribbon for best supporting actor.

Atto (archbishop of Milan)

Atto (Italian: Attone) was a Cardinal of the Catholic Church who lived in the 11th century.Born in Rome son of a noble family as a young man in 1062 he was elected by the chapter of the Milan cathedral Archbishop of Milan, Attone was elected archbishop in front of a papal legate but the decision of the chapter of the cathedral didn't receive the placet of emperor Henry IV so he coundn't be enthroned.Attone was so forced to left Milan and he reached Rome where he lived in the Church of San Marco is title as Cardinal.During his stay in Rome Attone wrote a book about canon law in that book he supported the supremacy of the bishop of Rome over the civil authorities following the teaching of pope Gregory VII.

The date of his death is unclear for some author the date of the death is around 1080, others authors identify him as a Cardinal Bishop of Palestrina who dies after 1085 and after to be excommunicated by pope Gregory VII.

Atto Mensah

Atto Ayippey Mensah (born 1964) is a Ghanaian-born Sierra Leonean football coach and former player. He lives in the Netherlands and holds both Sierra Leonean and Dutch citizenship.

He came to Sierra Leone in 1980 and played for East End Lions and won the championship in 1980 and 1985. Mensah gained Sierra Leonean citizenship in 1987.

Mensah made his international debut for Sierra Leone in the 1988 African Cup of Nations qualification competition in a 2-0 victory over Nigeria in July 1987. He made 6 caps before moving to the Netherlands in 1989. There he had a trial at Sparta Rotterdam and played in the amateur ranks ending at ASV Arsenal. He got his UEFA B-licence in the Netherlands and worked as a youth coach. He is currently head coach of amateur-side ASV Arsenal in Amsterdam.Mensah was appointed by the Ministry of Sport in September 2014, replacing the Northern Irish manager Johnny McKinstry in the role of manager of the Sierra Leone national football team for the remaining 2015 Africa Cup of Nations qualification matches. He was replaced by John Ajina Sesay, who was appointed by the Sierra Leone Football Association in October 2014.

Atto of Vercelli

Atto of Vercelli or Atto II (885–961) was a Lombard who became bishop of Vercelli in 924. He served as Grand Chancellor to Hugh of Provence and Lothar II, both Kings of Italy in the 10th century. During his time as bishop, Atto was known for his devotion to the welfare of the people in his diocese, both temporal and spiritual, and the vigor with which he attacked ecclesial corruption. He wrote several works in his lifetime. His major compositions include Polypticum, a treatise on the morality of Italy in the day; De pressuris ecclesiasticis, an essay regarding ecclesiastical authority; and the Capitulare, a collection of canon law from his area, including some of the False Decretals, augmented by his own additions of ecclesiastic law. A small selection of his sermons survives in written form. He died in 961.


An attosecond is 1×10−18 of a second (one quintillionth of a second). For context, an attosecond is to a second what a second is to about 31.71 billion years.The word "attosecond" is formed by the prefix atto and the unit second. Atto- was derived from the Danish word for eighteen (atten). Its symbol is as.

An attosecond is equal to 1000 zeptoseconds, or ​1⁄1000 of a femtosecond. Because the next higher SI unit for time is the femtosecond (10−15 seconds), durations of 10−17 s and 10−16 s will typically be expressed as tens or hundreds of attoseconds:

Times which can be expressed in attoseconds:

1 attosecond: the time it takes for light to travel the length of two hydrogen atoms

24 attoseconds: the atomic unit of time

43 attoseconds: the shortest pulses of laser light yet created

53 attoseconds: the second-shortest pulses of laser light created

100 attoseconds: fastest-ever view of molecular motion

200 attoseconds (approximately): half-life of beryllium-8, maximum time available for the triple-alpha process for the synthesis of carbon and heavier elements in stars

320 attoseconds: estimated time it takes electrons to transfer between atoms

Could It Happen Here?

Could It Happen Here? (Italian: Italia: ultimo atto?) is a 1977 Italian political fiction thriller film written and directed by Massimo Pirri.

Giangan language

Giangan (also known as Bagobo, Clata, Atto, Eto, Guanga, Gulanga, Jangan) is an Austronesian language of the southern Philippines. It is spoken on the eastern slopes of Mount Apo in Davao del Sur Province, as well as in Davao City (Ethnologue). They occupy a very small territory stretching from Catalunan to Calinan within Davao City.

The nearby Tagabawa language is also known as Bagobo, and is not to be confused with Giangan.

Last Days of Mussolini

Last Days of Mussolini (Italian: Mussolini: Ultimo atto) is a 1975 Italian historical drama film directed by Carlo Lizzani and starring Rod Steiger, Franco Nero and Lisa Gastoni. The film depicts the downfall of the Italian dictator Benito Mussolini.

Lotka–Volterra equations

The Lotka–Volterra equations, also known as the predator–prey equations, are a pair of first-order nonlinear differential equations, frequently used to describe the dynamics of biological systems in which two species interact, one as a predator and the other as prey. The populations change through time according to the pair of equations:


x is the number of prey (for example, rabbits);
y is the number of some predator (for example, foxes);
and represent the instantaneous growth rates of the two populations;
t represents time;
α, β, γ, δ are positive real parameters describing the interaction of the two species.

The Lotka–Volterra system of equations is an example of a Kolmogorov model, which is a more general framework that can model the dynamics of ecological systems with predator–prey interactions, competition, disease, and mutualism.

My Friends (film)

My Friends (Italian: Amici miei) is a 1975 Italian comedy-drama film directed by Mario Monicelli.The film project belonged to Pietro Germi, who had no chance to make it happen because of his untimely death. The opening credits of the film, in fact, paid tribute to the author with the words "a film by Pietro Germi" which is followed only later by "directed by Mario Monicelli".

The film, which made it to number one on the Italian box-office in front of Steven Spielberg's Jaws, was followed by two sequels, Amici miei Atto II (1982, also by Monicelli), Amici miei Atto III (1985), directed by Nanni Loy.

Osman Ali Atto

Osman Hassan Ali Atto (1940 – August 5, 2013), also spelled Ato, was a controversial Somali businessman.

Peppino De Filippo

Peppino De Filippo (24 August 1903 – 27 January 1980) was an Italian actor.De Filippo was born in Naples, brother of actor and dramatist Eduardo De Filippo and of Titina De Filippo. He made his stage debut at the age of six. He played in several movies such as Rome-Paris-Rome, Variety Lights, A Day in Court, Ferdinand I, King of Naples and Boccaccio '70. He is however most remembered for his several artistic partnerships with Totò, on movies such as Totò, Peppino e la malafemmina and La banda degli onesti.

He died in Rome.

Woodbine Mile

The Woodbine Mile is a Grade I stakes race on turf for Thoroughbred racehorses three years old and up held annually in mid September at Woodbine Racetrack in Toronto, Canada. Currently sponsored by Ricoh, the Woodbine Mile offers a purse of C$800,000, a reduction from the previous purse of $1,000,000 (1999-2016).

Part of the Breeders' Cup Challenge series, the winner of the Woodbine Mile automatically qualifies for the Breeders' Cup Mile.The inaugural race in 1988 was sponsored by Molson Breweries with a purse of $750,000 and run as the Molson Export Challenge, reflecting the name of the company's flagship beer. It was changed to the Molson Export Million when the purse was increased to $1 million. In 1999, under new sponsorship it was renamed and raced as the Atto Mile until 2006.

Since inception, the race has been run at three different distances:

1 mile on turf: 1997–present

​1 1⁄8 miles on dirt: 1991-1996

​1 1⁄4 miles on dirt: 1988-1990Originally restricted to three-year-olds on the dirt, with the modification to one mile on turf in 1997 the race was also made open to older horses. As a result of the change from dirt to turf, the race was ungraded in 1997 and 1998.

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