Answer to Puzzle Contest (from the winner):

"Tree

THINKARBOREAL is one of the possible decoded messages when 905371918587513 is interpreted as a concatenation of the atomic numbers which represent corresponding symbols of the periodic table."

Here is an explanation that may make more sense to you, from David Fontes:

"The numbers:

> 905371918587513

if broken up like so:

90 53 7 19 18 5 8 75 13

are the atomic numbers for the following elements

Th I N K Ar B O Re Al

or, "think arboreal," which leads me to believe that the chemist is thinking about:

a tree!"

Winner: Shivaji Marisarla

Contest Statistics: Newsletter sent to 294299 subscribers, 11 answers submitted, 9 answers correct, 81.82% accuracy. Chance of a correct answer winning: 11.11%.