International Atomic Time (TAI, from the French name Temps Atomique International) is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid. It is the basis for Coordinated Universal Time (UTC), which is used for civil timekeeping all over the Earth's surface, and for Terrestrial Time, which is used for astronomical calculations. Since 31 December 2008 when the last leap second was added,^[1] TAI has been exactly 34 seconds ahead of UTC. The 34 seconds results from the initial difference of 10 seconds at the start of 1972, plus 24 leap seconds in UTC since 1972. A new leap second is scheduled to be added at the end of 30 June 2012.^[2]

Time coordinates on the TAI scales are conventionally specified using traditional means of specifying days, carried over from non-uniform time standards based on the rotation of the Earth. Specifically, both Julian Dates and the Gregorian calendar are used. TAI in this form was synchronised with Universal Time at the beginning of 1958, and the two have drifted apart ever since, due to the changing motion of the Earth.

Operation[link]

TAI as a time scale is a weighted average of the time kept by over 200 atomic clocks in over 50 national laboratories worldwide.^[3] The clocks are compared using GPS signals and Two-Way Satellite Time and Frequency Transfer.^[4] Due to the averaging it is far more stable than any clock would be alone (see signal averaging for a discussion). The majority of the clocks are caesium clocks; the definition of the SI second is written in terms of caesium.^[5]

The participating institutions each broadcast, in real time, a frequency signal with time codes, which is their estimate of TAI. Time codes are usually published in the form of UTC, which differs from TAI by a well-known integer number of seconds. These time scales are denoted in the form UTC(NPL) in the UTC form, where NPL in this case identifies the National Physical Laboratory, UK. The TAI form may be denoted TAI(NPL). The latter is not to be confused with TA(NPL), which denotes an independent atomic time scale, not synchronised to TAI or to anything else.

The clocks at different institutions are regularly compared against each other. The International Bureau of Weights and Measures (BIPM, France), combines these measurements to retrospectively calculate the weighted average that forms the most stable time scale possible. This combined time scale is published monthly in Circular T, and is the canonical TAI. This time scale is expressed in the form of tables of differences UTC-UTC(k) (equivalent to TAI-TAI(k)) for each participating institution k. (The same circular also gives tables of TAI-TA(k), for the various unsynchronised atomic time scales.)

Errors in publication may be corrected by issuing a revision of the faulty Circular T or by errata in a subsequent Circular T. Aside from this, once published in Circular T the TAI scale is not revised. In hindsight it is possible to discover errors in TAI, and to make better estimates of the true proper time scale. Doing so does not create another version of TAI; it is instead considered to be creating a better realisation of Terrestrial Time (TT).

History[link]

Atomic timekeeping services started experimentally in 1955, using the first caesium atomic clock at the National Physical Laboratory, UK (NPL). Early atomic time scales consisted of quartz clocks with frequencies calibrated by a single atomic clock; the atomic clocks were not operated continuously. The "Greenwich Atomic" (GA) scale began in 1955 at the Royal Greenwich Observatory. The United States Naval Observatory began the A.1 scale 13 September 1956, using an Atomichron commercial atomic clock, followed by the NBS-A scale at the National Bureau of Standards, Boulder, Colorado. The International Time Bureau (BIH) began a time scale, T_m or AM, in July 1955, using both local caesium clocks and comparisons to distant clocks using the phase of VLF radio signals. Both the BIH scale and A.1 was defined by an epoch at the beginning of 1958: it was set to read Julian Date 2436204.5 (1 January 1958 00:00:00) at the corresponding UT2 instant. The procedures used by the BIH evolved, and the name for the time scale changed: "A3" in 1963 and "TA(BIH)" in 1969.^[6] This synchronisation was inevitably imperfect, depending as it did on the astronomical realisation of UT2. At the time, UT2 as published by various observatories differed by several centiseconds.

The SI second was defined in terms of the caesium atom in 1967, and in 1971 it was renamed International Atomic Time (TAI).^[7]

Also in 1961, UTC began. UTC is a discontinuous time scale composed from segments that are linear transformations of atomic time, the discontinuities being arranged so that UTC approximated UT2 until the end of 1971, and UT1 thereafter. This was a compromise arrangement for a broadcast time scale: a linear transformation of the BIH's atomic time meant that the time scale was stable and internationally synchronised, while approximating UT1 means that tasks such as navigation which require a source of Universal Time continue to be well served by public time broadcasts.^[8]

In the 1970s, it became clear that the clocks participating in TAI were ticking at different rates due to gravitational time dilation, and the combined TAI scale therefore corresponded to an average of the altitudes of the various clocks. Starting from Julian Date 2443144.5 (1 January 1977 00:00:00), corrections were applied to the output of all participating clocks, so that TAI would correspond to proper time at mean sea level (the geoid). Because the clocks had been on average well above sea level, this meant that TAI slowed down, by about 10⁻¹². The former uncorrected time scale continues to be published, under the name EAL (Echelle Atomique Libre, meaning Free Atomic Scale).^[9]

The instant that the gravitational correction started to be applied serves as the epoch for Barycentric Coordinate Time (TCB), Geocentric Coordinate Time (TCG), and Terrestrial Time (TT). All three of these time scales were defined to read JD 2443144.5003725 (1 January 1977 00:00:32.184) exactly at that instant. (The offset is to provide continuity with the older Ephemeris Time.) TAI was henceforth a realisation of TT, with the equation TT(TAI) = TAI + 32.184 s.^[10]

The continued existence of TAI was questioned in a 2007 letter from the BIPM to the ITU-R which stated "In the case of a redefinition of UTC without leap seconds, the CCTF would consider discussing the possibility of suppressing TAI, as it would remain parallel to the continuous UTC."^[11]

See also[link]

• Time and frequency transfer
• Clock synchronization
• Network Time Protocol
• Precision Time Protocol, a related though separate technology
• Magneto-optical trap

Notes[link]

References[link]

• "BIPM - International Atomic Time". International Bureau of Weights and Measures. http://www.bipm.org/en/scientific/tai/tai.html. Retrieved 14 February 2012. 
• "CCTF 09-27". International Bureau of Weights and Measures. 3 September 2007. http://www.bipm.org/cc/CCTF/Allowed/18/CCTF_09-27_note_on_UTC-ITU-R.pdf. 
• "Circular T 263". International Bureau of Weights and Measures. 14 December 2009. ftp://ftp2.bipm.org/pub/tai/publication/cirt.263. 
• Gambis, Daniel (4 July 2009). "Bulletin C 38". Paris: IERS EOP PC, Observatoire de Paris. ftp://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat. Retrieved 4 January 2010. 
• "History of TAI−UTC". Time Service Dept., United States Naval Observatory. 2009. ftp://maia.usno.navy.mil/ser7/tai-utc.dat. Retrieved 4 January 2010. 
• McCarthy, D. D.; Seidelmann, P. K. (2009). TIME—From Earth Rotation to Atomic Physics. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA. ISBN 978-3-527-40780-4. 

External links[link]

• Bureau International des Poids et Mesures: TAI
• Time and Frequency Section - National Physical Laboratory, UK
• IERS website
• NIST Time and Frequency FAQs
• History of time scales
• NIST cesium fountain standard
• Optical frequency comb for metrology and timekeeping
• Japan Standard Time Project, NICT, Japan

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This article has multiple issues. Please help improve it or discuss these issues on the talk page. This biography of a living person needs additional citations for verification. Tagged since January 2010. It may require cleanup to meet Wikipedia's quality standards. Tagged since February 2009.

George Friedman is an American political scientist and author. He is the founder, chief intelligence officer, financial overseer, and CEO of the private intelligence corporation Stratfor.^[1] He has authored several books, including The Next 100 Years, The Next Decade, America's Secret War, The Intelligence Edge, The Coming War With Japan and The Future of War.^[2]

Biography[link]

Friedman’s childhood was shaped directly by international conflict. He was born in Hungary to Holocaust survivors. His family fled Hungary when he was a child to escape the Communist regime, settling first in a camp for displaced persons in Austria and then immigrating to the United States, where he attended public schools in New York City, and was an early designer of computerized war games. Friedman describes his family’s story as “a very classic story of refugees making a new life in America." He received a B.A. at the City College of New York, where he majored in political science, and a Ph.D. in government at Cornell University.^[2]

Prior to joining the private sector, Friedman spent almost twenty years in academia, teaching political science at Dickinson College. During this time, he also regularly briefed senior commanders in the armed services as well as the Office of Net Assessments, SHAPE Technical Center, the U.S. Army War College, National Defense University and the RAND Corporation, on security and national defense matters.^{[citation needed]}

Friedman pursued political philosophy with his early work focusing on Marxism, as well as international conflict, including examination of the U.S.-Soviet relationship from a military perspective. After the collapse of the Soviet Union, Friedman studied potential for a U.S.-Japan conflict and co-authored The Coming War with Japan in 1991. He is also the author or co-author of books examining topics as diverse as the Frankfurt School and warfare, including The Future of War, The next hundred years, The Intelligence Edge, and America’s Secret War.

In 1996, he founded STRATFOR, a private intelligence and forecasting company, and has served as the company's CEO and Chief Intelligence Officer.

Personal life[link]

Friedman is married to Meredith Friedman (née LeBard), has four children, and lives in Austin, Texas.

Books[link]

• The Political Philosophy of the Frankfurt School (1981). Cornell University Press. ISBN 0-8014-1279-X.
• Coming War With Japan, with Meredith LeBard (1991). St Martins Press. Reprint edition, 1992, ISBN 0-312-07677-0.
• The Future of War: Power, Technology and American World Dominance in the Twenty-First Century with Meredith Friedman (1996). 1st ed., Crown Publishers, ISBN 0-517-70403-X. St. Martin's Griffin, 1998, ISBN 0-312-18100-0.
• The Intelligence Edge: How to Profit in the Information Age with Meredith Friedman, Colin Chapman, and John Baker (1997). Crown, 1st edition. ISBN 0-609-60075-3.
• America's Secret War: Inside the Hidden Worldwide Struggle Between the United States and Its Enemies (2004). Doubleday, 1st ed, ISBN 0-385-51245-7. Broadway, reprint edition (2005). ISBN 0-7679-1785-5.
• The Next 100 Years: A Forecast for the 21st Century (2009). Doubleday. ISBN 0-385-51705-X.
• The Next Decade: What the World Will Look Like (2010). ISBN 0-385-53294-6.

External links[link]

• Bio of Friedman at STRATFOR's website.
• Bio of Friedman at America's Secret War's website.
• Bio of Friedman at New Global Initiative's website.
• Friedman quotes at ThinkExist.com.
• The Iranian Election and the Revolution Test. George Friedman writes on Ahmadinejad's election and revolt against alleged fraud.
• Booknotes interview with Friedman and Meredith LeBard on The Coming War With Japan, June 9, 1991.

References[link]

Yukiya Amano 天野之弥
Director General of the International Atomic Energy Agency
Incumbent
Assumed office 1 December 2009
Preceded by	Mohamed ElBaradei
Personal details
Born	(1947-05-09) 9 May 1947 (age 65) Kanagawa, Japan
Political party	Liberal Democratic Party
Alma mater	University of Tokyo University of Franche-Comté University of Nice Sophia Antipolis

Yukiya Amano (天野 之弥, Amano Yukiya^?, born 9 May 1947) is the current Director General of the International Atomic Energy Agency (IAEA), having been elected to the position in July 2009. Amano previously served as a Japanese diplomat and international civil servant for the United Nations and its subdivisions.

Early life[link]

Amano was born in Kanagawa Prefecture, Japan, in 1947. He started his studies at the University of Tokyo in 1968. After graduating from the Faculty of Law, he joined the Ministry of Foreign Affairs in April 1972.^[1] He specialized in the international disarmament issue and nuclear nonproliferation efforts.^[2] In 1973–1974, he studied at the University of Franche-Comté and in 1974–1975, at the University of Nice, France.^[3]

Career[link]

Japanese Ministry of Foreign Affairs[link]

Amano held different posts in the foreign ministry such as the Director of the Science Division and Director of the Nuclear Energy Division in 1993. As a member of the Diplomatic service, he was posted in the Embassies of Japan in Vientiane, Washington and Brussels, in the Delegation of Japan to the Conference on Disarmament in Geneva and was Consul General of Japan in Marseille.^[2][3]

In August 2002, he was appointed Director-General for Arms Control and Scientific Affairs, and in August 2004, he was appointed Director-General of the Disarmament, Nonproliferation and Science Department.^[2] In these positions, he was involved in international negotiations such as the Nuclear Non-Proliferation Treaty extension, the Comprehensive Nuclear-Test-Ban Treaty, the Biological Weapons Convention verification protocol, amendment of the Convention on Certain Conventional Weapons and the International Code of Conduct against Ballistic Missile Proliferation. He represented Japan as a governmental expert on the UN Panel on Missiles in April 2001 and in the UN Expert Group on Disarmament and Nonproliferation Education in July 2001.^[2]

International Atomic Energy Agency[link]

In 2005, Amano served as the ambassador from Japan to the IAEA. From September 2005 to September 2006, Amano served as the Chairman of the IAEA Board of Governors.^[3] During this time, the IAEA and its Director General Mohamed ElBaradei received the Nobel Peace Prize. Amano represented the IAEA as the chairman at the Nobel Prize award ceremony held in December 2005.^[4]

In September 2008, the Japanese government announced that it had nominated Yukiya Amano to be the next Director General of the IAEA.^[5] On 2 July 2009, he was elected by the Board of Governors as Director General for the IAEA in the sixth round of voting. He defeated South African representative Abdul Samad Minty, his primary rival.^[6][7][8] On 3 July 2009 all 145 IAEA member states formally appointed Yukiya Amano "by acclamation".^[7][9]

On 1 December 2009, Amano began his first term as Director General of the International Atomic Energy Agency.^[10]

In November 2010, British newspaper The Guardian reported on a U.S. diplomatic cable originating a year earlier in Vienna and supplied to the newspaper by WikiLeaks, detailing a meeting between Amano and an American ambassador. The author of the cable summarized a statement by Amano in which the latter offered that he "was solidly in the U.S. court on every key strategic decision, from high-level personnel appointments to the handling of Iran's alleged nuclear weapons program."^[11] In March 2012, Amano was accused by several former senior IAEA officials of pro-western bias, over-reliance on unverified intelligence and of sidelining sceptics.^[12]

Views on nuclear proliferation[link]

In an interview mid-2009 with the Austrian newspaper Die Presse, Yukiya Amano said he was "resolute in opposing the spread of nuclear arms because I am from a country that experienced Hiroshima and Nagasaki".^[1]

Involvement in nuclear emergency after Japanese earthquake and tsunami[link]

After the Fukushima I nuclear accidents on 11 March 2011, Amano held a meeting with Prime Minister Naoto Kan in Tokyo on 18 March. Amano, "who had just arrived from the agency’s headquarters ... said he would dispatch a team 'within days' to monitor radiation near the damaged plant." At the meeting, Amano said Kan "agreed on the necessity to disclose as much information as possible on the unfolding nuclear crisis in Fukushima. 'What’s important is coordination with international society and better transparency,' Mr. Amano told reporters before the meeting."^[13]

Personal[link]

Amano is married and speaks English, French and his native language, Japanese.^[14]

Publications[link]

• A Japanese View on Nuclear Disarmament, The Non-Proliferation Review, 2002
• The Significance of the NPT Extension, Future Restraints on Arms Proliferation, 1996
• La Non Proliferation Nucleaire en Extreme-Orient, Proliferation et Non-Proliferation Nucleaire, 1995
• Sea Dumping of Liquid Radioactive Waste by Russia, Gaiko Jiho, 1994

See also[link]

• Nuclear Security Summit (2010) (attended)

References[link]

External links[link]

Wikimedia Commons has media related to: Yukiya Amano

• IAEA Director General's Corner