What's New?
.	December Journal
.	December Newsletter
.	Online Registration for HPS 2010 Midyear Meeting Now Available
.	NRC Academic Program Nuclear Education Grants, FY2010, Now Accepting Applications
.	EPA's STAR Graduate and GRO Undergraduate Fellowship Funding Now Accepting Applications

Upcoming Events
.	2010 HPS Midyear Topical Meeting Radiation Risk Communication to the Public 24-27 January 2010 Albuquerque, NM
.	2010 HPS Professional Development School Radiation Risk Communication: Issues and Solutions 27-29 January 2010 Albuquerque, NM

21 November 2009

Half-life (effective)

The time required for a radionuclide contained in a biological system, such as a human or an animal, to reduce its activity by one-half as a combined result of radioactive decay and biological elimination.