HALF-LIFE

measure of the average lifetime of a radioactive substance (see radioactivity) or an unstable subatomic particle. One half-life is the time required for one half of any given quantity of the substance to decay. For example, the half-life of a particular radioactive isotope of thorium is 8 minutes. If 100 grams of the isotope are originally present, then only 50 grams will remain after 8 minutes, 25 grams after 16 minutes (2 half-lives), 12.5 grams after 24 minutes (3 half-lives), and so on. Of course the 87.5 grams that are no longer present as the original substance after 24 minutes have not disappeared but remain in the form of one or more other substances in the isotope's radioactive decay series. Individual decays are random and cannot be predicted, but this statistical measure of the great number of atoms in the sample is very accurate. The half-life of a radioactive isotope is a characteristic of that isotope and is not affected by any change in physical or chemical conditions.

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The Columbia Encyclopedia, Sixth Edition Copyright© 2004, Columbia University Press. Licensed from Lernout & Hauspie Speech Products N.V. All rights reserved.

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Questia Books and Articles on: Half Life
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books on: Half Life  - 74448 results

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1.
Senescence, the Last Half of Life
Book by G. Stanley Hall; D. Appleton & Company, 1922
Subjects: Old Age
SENESCENCE THE LAST HALF OF LIFE BY G. STANLEY HALL...SENESCENCE THE LAST HALF OF LIFE BY G. STANLEY HALL...think vaguely of it as half way between birth and...senescence. If we think of life as a binomial curve rising...
2.
The Horrors of the Half-Known Life: Male Attitudes toward Women and Sexuality in Nineteenth-Century America
Book by G. J. Barker-Benfield; Routledge, 2000
Subjects: Gynecology--United States--History--19th Century, Men--United States--Attitudes--History--19th Century, Sex Customs--United States--History--19th Century, Sex Role--United States--History--19th Century
...its time, The Horrors of the Half-Known Life is a startling portrait of male...the field, The Horrors of the Half-Known Life is one of the most important...in America. The Horrors of the Half-Known Life Male Attitudes toward Women...
3.
Half-Hearted Reform: Electoral Institutions and the Struggle for Democracy in Indonesia
Book by Dwight Y. King; Praeger, 2003
Subjects: Democracy--Indonesia, Elections--Indonesia, Indonesia--Politics And Government--1998-
...As in other states, Indonesian political life was structured formally by a hierarchy...village chief, subdistrict chief). More than half of the violations were classified as violations...had previously characterized political life. 50 The apparent relevance of the...
4.
Half the Battle: Civilian Morale in Britain during the Second World War
Book by Robert Mackay; Manchester University Press, 2002
Subjects: Great Britain--Social Life And Customs--1918-1945, World War, 1939-1945--Great Britain, World War, 1939-1945--Social Aspects--Great Britain
HALF THE BATTLE HALF THE BATTLE Civilian morale...realization of the facts of life and with it a readiness for...well as to describe. The second half of the book, therefore, is...recorded her view of those times half a century later: Our war was...
5.
A Half-Century of Type Design and Typography, 1895-1945
Book by Frederic W. Goudy, George L. McKay, Bruce Rogers; Typophiles, 1946
Subjects: Goudy, Frederic W--(Frederic William)--1865-1947, Printers--United States--Biography, Type And Type-Founding, Type Designers--United States--Biography
...eye this smaller type lacked wholly the life and variety displayed by the larger, and...drawings again and put into them the spark of life they now lack. I insert this account...to cut one size to show that there was life in the old boy yet. Some months later...
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journal articles on: Half Life  - 39293 results

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1.
Age- and Concentration-Dependent Elimination Half-Life of 2,3,7,8-Tetrachlorodibenzo-P-Dioxin in Seveso Children
Journal article by Brent D. Kerger, Hon-Wing Leung, Paul Scott, Dennis J. Paustenbach, Larry L. Needham, Donald G. Patterson Jr., Pier M. Gerthoux, Paolo Mocarelli; Environmental Health Perspectives, Vol. 114, 2006
...Concentration-Dependent Elimination Half-Life of 2,3,7,8-Tetrachlorodibenzo-P-Dioxin...concentrations to calculate TCDD elimination half-life. Variables examined by statistical...explosion in July 1976. RESULTS: TCDD half-life in persons < 18 years of age averaged...
2.
Half-Life of Serum Elimination of Perfluorooctanesulfonate, Perfluorohexanesulfonate, and Perfluorooctanoate in Retired Fluorochemical Production Workers
Journal article by Geary W. Olsen, Jean M. Burris, David J. Ehresman, John W. Froehlich, Andrew M. Seacat, John L. Butenhoff, Larry R. Zobel1; Environmental Health Perspectives, Vol. 115, 2007
Subjects: 3M Co.--Research, Chemical workers--Health aspects, Chemical workers--Research, Paper products industry--Research, Perfluorocarbons--Complications and side effects, Perfluorocarbons--Research
Half-Life of Serum Elimination of Perfluorooctanesulfonate...reported an approximate terminal elimination half-life of 200 days for PFOS in male and female...study was to estimate the serum elimination half-life of PFOS, PFHS, and PFOA in humans through...
3.
Unbiased Estimation of the Half-Life to PPP Convergence in Panel Data
Journal article by Chi-Young Choi, Nelson C. Mark, Donggyu Sul; Journal of Money, Credit & Banking, Vol. 38, 2006
Subjects: Commodity price indexes--Evaluation, Prejudice--Evaluation, Prejudices--Evaluation, Purchasing power--Evaluation
Unbiased Estimation of the Half-Life to PPP Convergence in Panel Data...data to estimate the convergence half-life of PPP deviations is straightforward...important due to the nonlinearity of the half-life formula because small differences...
4.
Half Life
Journal article by Robert Milliken; Bulletin of Concerned Asian Scholars, Vol. 18, 1986
Subjects: Asia
Half Life Deadly Snow by Robert Milliken * HALF LIFE, a film by Dennis ORourke, available from...Australian filmmaker Dennis ORourkes new film Half Life is shown for the first time at the Melbourne...
5.
The Brooke Story: A Professional Half-Life in International Business
Journal article by Michael Z. Brooke; Journal of International Business Studies, Vol. 25, 1994
Subjects: College teachers--Biography, International business enterprises--Research
THE BROOKE STORY: A PROFESSIONAL HALF-LIFE IN INTERNATIONAL BUSINESS. by...by the request, but here goes. The life began on 5 November 1921 -- a day on...to be born on. After living all my life in Cambridge, I was determined to get...
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magazine articles on: Half Life  - 28889 results

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1.
Half-Life: A Project for Artforum by Nick Waplington
Magazine article by Jayne Anne Phillips; Artforum International, Vol. 31, March 1993
Subjects: Nuclear warfare--Illustrations, photographs, etc., Photographers--Criticism, interpretation, etc., Waplington, Nick--Criticism, interpretation, etc.
Half-life: a project for Artforum by Nick Waplington by Jayne Anne Phillips...nuclear age come to mind, words like "radioactive," "chemotherapy," and "half-life." As veterans of the benefits and dangers of nuclear energy, we might all...
2.
Half a Life
Magazine article by Paul Evans; Book, November 2001
Subjects: Books--Reviews, Half a Life (Book)--Reviews
Half a Life by Paul Evans Half a Life V.S. NAIPAUL...being, are tricky to pull off--yet can be priceless. With Half a Life, Naipaul makes masterful fiction of the story of a sad, unsung...
3.
Righteous Gentiles: How Pius XII and the Catholic Church Saved Half a Million Jews from the Nazis
Magazine article by Jr. William Doino; First Things: A Monthly Journal of Religion and Public Life, March 2006
Subjects: Books--Book reviews, Righteous Gentiles: How Pius XII and the Catholic Church Saved Half a Million Jews from the Nazis (Book)
...Righteous Gentiles: How Pius XII and the Catholic Church Saved Half a Million Jews from the Nazis. by Jr. William Doino RIGHTEOUS GENTILES: How Plus XII AND THE CATHOLIC CHURCH SAVED HALF A MILLION JEWS FROM "THE NAZIS by RONALD J. RYCHLAK Spence, 400...
4.
Half a Life
Magazine article; The Atlantic Monthly, Vol. 288, November 2001
Subjects: Fiction
Half a Life. by V. S. Naipaul Knopf...with prostitutes. In the first half of this novel the parallels between Willies life and that of his creator are...humiliated and alone at the end. Half a Life has a few problems, including...
5.
Reality Bites: Mike Bullen's Version of Life at 40 Tells Only Half the Story, Writes Andrew Billen
Magazine article by Andrew Billen; New Statesman, Vol. 133, February 23, 2004
Subjects: Life Begins (Television program)--Television program reviews, Television programs--Television program reviews
...Reality Bites: Mike Bullens Version of Life at 40 Tells Only Half the Story, Writes Andrew Billen...Morshead, fears we will rumble that Life Begins is less serious than its...has this time written less than half the story. Andrew Billen is a...
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newspaper articles on: Half Life  - 98436 results

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1.
Scandal of Oaps' Half-Life
Newspaper article; Sunday Mercury (Birmingham, England), January 1, 2006
Scandal of Oaps Half-Life. ONE of the nightmares of living in this country is that one day...stimulation, stripped of identity and probably doped, we can expect a half-life of permanent daytime television and being shouted at by strangers. And...
2.
Orange Box Set That Will Blow You Away; Keep Your Cool: Fortress 2 Is One of Five Terrific PS3 Games in Half-Life 2: The Orange Box Orange Box Set That
Newspaper article; The Daily Mail (London, England), January 11, 2008
Subjects: Computer action games, Computer entertainment systems
...One of Five Terrific PS3 Games in Half-Life 2: The Orange Box Orange Box Set That. Byline: James OBrien Half-Life 2: The Orange Box (EA ) PS3 (pounds...Person Shooters (FPS) herethe original Half-Life 2 plus two new instalmentswhich invite...
3.
A Half-Life for Gen. Halftrack
Newspaper article by Suzanne Fields; The Washington Times, July 7, 1997
A half-life for Gen. Halftrack by Suzanne Fields Amos Halftrack cant get his fantasies adjusted fast enough. Halftrack, as every...
4.
Swiss Life Asset Management Profits Down 50% in First Half
Newspaper article; Financial News, September 10, 2003
Subjects: Insurance industry, Life insurance industry, Portfolio management, Swiss Life
Swiss Life Asset Management Profits Down 50% in First Half. Byline: Pirkko...50% on the first half of 2002, despite...businesses.In May, Swiss Life sold Scweizerische...group level, Swiss Life returned to profit in the first half, generating Sfr66m...
5.
Turbulent First Half for Standard Life
Newspaper article; The Journal (Newcastle, England), August 6, 2009
Subjects: Insurance industry, Standard Life Assurance Co.
Turbulent First Half for Standard Life. SAVERS cutting back...business in the first half of the year, life and pensions giant Standard...its schemes. Standard Life said the number of customers...3.1bn during the first half of the year. This also...
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encyclopedia articles on: Half Life  - 264 results

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1.
Half-Life
Encyclopedia article; The Columbia Encyclopedia, Sixth Edition, 2009
HALF-LIFE measure of the average lifetime of a...or an unstable subatomic particle. One half-life is the time required for one half of any...the substance to decay. For example, the half-life of a particular radioactive isotope of...
2.
Radon
Encyclopedia article; The Columbia Encyclopedia, Sixth Edition, 2009
...highly radioactive and has a short half-life. The chief use of radon is in the...three occur naturally. Radon-222 (half-life 3.82 days) is produced by the decay of radium-226. Radon-220 (half-life 55 sec), also called thoron, is produced...
3.
Rutherfordium
Encyclopedia article; The Columbia Encyclopedia, Sixth Edition, 2009
...isolated an isotope with mass number 260 and a half-life of 0.3 sec by bombarding plutonium-242 atoms with...ions to creates isotopes with mass numbers 257 (half-life of 4.8 sec), 259 (half-life of 3 sec), and possibly 258 (half-life of 13 msec...
4.
Polonium
Encyclopedia article; The Columbia Encyclopedia, Sixth Edition, 2009
...radioactive. The most stable, polonium-209, has a half-life of about 103 years. Polonium-208 (half-life about 3 years) is the only other polonium isotope with a half-life over one year. Although these two isotopes can...
5.
Californium
Encyclopedia article; The Columbia Encyclopedia, Sixth Edition, 2009
...stable isotope. Californium-249 (half-life 351 years) is most useful for chemical...oxyfluoride, and oxide. Californium-252 (half-life 2.6 years) is produced in nuclear...particles, resulting in californium-245 (half-life 45 min). ____________________ Copyright...
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