With the holiday season well upon us, thoughts for many will turn to shopping. Katherine Haxton takes her chemist’s eye (and nose) to the mall with her.

When we arrived at the shopping centre, the first bit of chemistry we encountered was the old favorite: stink bombs […] small glass vials of ammonium sulfide which react with the moisture in air to produce a mixture of hydrogen sulfide (rotten eggs smell) and ammonia gases. Sometimes other sulfur containing compounds may be used such as thiols (mercaptans) which smell pretty foul. Methanethiol (methyl mercaptan) is apparently responsible for ‘asparagus pee’, ethanethiol (ethylmercaptan) is more familiar as the smell of natural gas, because it is added to odorless natural gas so that we might detect a leak. We’re capable of detecting many thiols at extremely low concentrations, and some people are more sensitive to the smell than others. I find that skunk (butylmercaptan) in low concentrations smells like burnt toast. In any case, the odor of stink bombs made parts of the shopping trip quite unpleasant and I’d like to find the small children who play such pranks and make sure that Santa does not visit them this year.

Meanwhile, Heather Etchevers takes a critical look at the shortcomings of the postdoctoral research system, while Mike Fowler notes that the findings of one in three top papers are later refuted by other authors, according to PLoS Medicine.

Over in the forums, debate rages following Nature’s publication of a Commentary that aims to ‘help society accept the benefits of [cognitive] enhancement, given appropriate research and evolved regulation. “How dare they have the audacity to suggest such a thing?!,” emotes an anonymous commenter. A lively argument ensues.

Elsewhere, we have a new discussion area on nanopore sequencing —a technology hotly tipped to achieve the £1000 genome, and a wide-ranging topic on the fall (or rise) of science journalism.