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Copyright © 2012, Campbell R. Harvey. All Rights Reserved.

Half Life

In a pool of mortgages underlying a mortgage-backed security, the length of time it takes for half the aggregate principal to be repaid. A half life is normally about 12 years, but this may vary depending on how often homeowners refinance their mortgages (which pays off all principal at once). Half lives are calculated for mortgage-backed securities issued or guaranteed by Freddie Mac, Fannie Mae, and Ginnie Mae.

Weighted Average Life

The amount of time for the principal on a loan or a mortgage to be paid off. The length of the weighted average life depends on the amount of principal paydowns and how often they are made. Once the WAL is calculated, one can determine how long it will take to pay off half of the remaining principal.
Farlex Financial Dictionary. © 2012 Farlex, Inc. All Rights Reserved


The length of time before half the principal on a debt is expected to be repaid through amortization or sinking fund payments. For example, a 25-year bond issue may require the issuer to retire 5% of the beginning principal commencing 5 years after the issue date. Thus, the bond issue has a half-life of 5 years plus the number of years required to retire half the issue, or 15 years. Mortgage-backed securities often have a relatively short half-life because many homeowners pay off or refinance their mortgages early. Also called average life.
Wall Street Words: An A to Z Guide to Investment Terms for Today's Investor by David L. Scott. Copyright © 2003 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. All rights reserved.
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Daniel Santi, co-founder and President of ProLynx, said: "Recently, ProLynx and Daiichi Sankyo published a novel technology for intra-vitreal half-life extension of small molecule drugs.
Xenon-124's half-life is 1.8 into 10^22 years (or 18,000,000,000,000,000,000,000 years), which really does make watching its radioactive decay an "ultra-rare" event.
Venturing into uneasy yet truthful territory, The Half-Life of Everything explores David's perspective and the frustrated sadness of his current situation.
The mean FVIII half-life (t[sub]1/2) was 10.99 [+ or -] 3.45 h (range 5.52-20.02 h), the mean IVR was 2.01 [+ or -] 0.42 IU/dl per IU/kg (range 1.24-3.02 IU/dl per IU/kg) and mean CL of FVIII is 4.34 [+ or -] 1.58 ml*kg −1*h −1 (range 2.29-7.90 ml*kg −1*h −1).
Laidlaw was an especially noteworthy departure for Half-Life , as he was the novelist-turned-games-writer who penned those games (Feliszek and Wolpaw contributed to Half-Life 2: Episode One and Episode Two ).
'Half-Life' was developed by Valve and released in 1998.
Valve also did not forget to implement the same update to the game's expansion packs "(http://steamcommunity.com/games/50/announcements/detail/1431432753542499784) Opposing Force " and "(http://steamcommunity.com/games/130/announcements/detail/1417921955573721276) Blue Shift ." The release notes for the expansions contain the same entries as the ones found in the patch notes for "Half-Life." And again, the updates for the two come several years after their release.
Although the estimated elimination half-life is long (about 11 days with a range of 6-24 days), the high molecular weight (about 154,000) should limit fetal exposure, at least in the first half of pregnancy The drug should be avoided in pregnancy, however, based on the animal data, the mechanism of action, and its combination with doxorubicin.
Scientists don't have a good understanding of such unusual decays; measuring the half-life would help pin down the details of the process and the nucleus' structure.
PEG conjugation is effective in prolonging the in vivo half-life of FVIIa, however, at the expense of a significant reduction in activity.
They were interpreted to be related to either the intrinsic elimination half-life, [t.sup.elim.sub.1/2], which indicates how fast the chemical is metabolized and excreted (elimination) from the human body (Noegrohati et al.
That means the Xen chunks of Half-Life still aren't here; they were also missing from the free, unfinished version of the game released in 2012.