A device that repels teenagers has won the peace prize at this year's Ig Nobels - the spoof alternative to the rather more sober Nobel prizes.
One winner studied why woodpeckers do not get headaches
Welshman Howard Stapleton's device makes a high-pitched noise inaudible to adults but annoying to teenagers.
Other winners included a US-Israeli study into how a finger up the rectum cures hiccups and a report into why woodpeckers do not get headaches.
All the research is real and published in often prestigious journals.
Unlike the recipients of the more illustrious awards, Ig Nobel winners get no cash reward.
Nevertheless eight of the 10 winners this year paid their own way to receive their prizes in Cambridge, Massachusetts.
Marc Abrahams, editor of science humour magazine Annals of Improbable Research, which co-sponsors the awards, said: "The prizes are intended to celebrate the unusual, honour the imaginative - and spur people's interest in science, medicine and technology."
The winners are given a one-minute acceptance speech, the time policed by a loud eight-year-old girl.
Real-life Nobel Laureates demonstrated winning research
This year's winners included:
- Maths: How many photos must be taken to almost ensure no-one in a group shot has their eyes closed, by Nic Svenson and Piers Barnes
- Ornithology: Why woodpeckers do not get headaches, by Ivan Schwab and the late Philip RA May
- Nutrition: Why dung beetles are fussy eaters, by Wasmia al-Houty and Faten al-Mussalam
- Acoustics: Why the sound of fingernails scraping on blackboards is so annoying, by D Lynn Halpern, Randolph Blake and James Hillenbrand
- Medicine: The Termination of Intractable Hiccups with Digital Rectal Massage, by Francis Fesmire, Majed Odeh, Harry Bassan and Arie Oliven.