53161
Small samples of rock were extracted from the blast area immediately after the test to study the explosion products , but no isotopes with mass number greater than 257 could be detected , despite predictions that such isotopes would have relatively long half-lives of α-decay .
 time: half-lives
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: half-lives 
Answer:
 time: half-lives