Definitions for "half-life"
the time it takes for one-half of a substance decaying in a first-order reaction to be destroyed. For radioactive substances, it is the time required for one-half of the initial amount of the radioactive isotope to decay. The half-lifeis a measure of the rate of the reaction being observed. For processes that are true first-order processes, such as radioactive decay, the half-life is independent of the quantity of material present, and it is thus a constant. The time it takes for one-half the remaining quantity of a radioactive isotope to decay will be the same regardless of how far the decay process has advanced. Some chemical reactions are also first order, and may be characterized as having a half-life. However, for chemical reactions the half-life will depend upon temperature and in some cases other environmental conditions, whereas for radioactive isotopes the rate of decay is largely independent of the environment.
The length of time required for a radioactive material to lose one-half of its radioactivity by decay (i.e., half of the radioactive element has spontaneously disintegrated).
The time necessary for half of the atoms of a parent isotope to decay into the daughter isotope.
a science fiction first-person shooter computer game developed by Valve Software and published by Sierra Studios in 1998, based on a heavily-modified Quake game engine
quake engine game from Valve software. see 3d games
Half-Life is a science fiction first-person shooter computer game series developed by Valve Software and published by Sierra Studios.
(433) HL Cancelled (13) HL Development (21) HL Lost HL Released (401) TWHL (22)
(435) HL Cancelled (13) HL Development (23) HL Lost HL Released (402) TWHL (22)
Keywords:  krach, alyson, rpb, aaron, quill
The calculated half-life of each mRNA. This calculation was performed using the rpb1-1 mutant, which is responsible for all class II transcription.
The point in the life of a mortgage-backed security guaranteed or issued by the Government National Mortgage Association, the Federal National Mortgage Association or the Federal Home Loan Mortgage Corporation when half the principal has been repaid.
Half-Life is a novel by Aaron Krach, his first, which was published in 2004 by Alyson Books. It discusses young love, coping with death and the issues facing gay youth. In 2005 it was nominated for both the Lambda Literary Award and the Violet Quill Award.
High Pressure Liquid Chromatography (HPLC) High-Throughput Screening (HTS)
Keywords:  fresno, saturday, night
Saturday night in Fresno
rater at which a drug disappears fromt eh body through metabolism, excretion or both.
Keywords:  flare, solar
Solar Flare
Keywords:  future, principal, paid, date, off
The future date on which half of a mortgages principal will have been paid off.