More data needed, but:
I thought it was fairly well known that infrasonic sound can affect people negatively in terms of feelings of malaise and "doom."
It would be hard to project infrasound (below, say, 16Hz) with any direction, but higher frequency sounds can be pretty directional. I wonder if someone's figured out a way to project two ultrasound (above, say, 20 KHz) beams* such that where they intersect, they heterodyne to form a low frequency sound at that point.
30,000 Hz + 30,010 Hz results in a beat frequency (heterodyned) of 10 Hz.
Maybe they should see what dogs think about it. :)
Or maybe it's in the water.
Is the ejection of two diplomats at this point in time causal, or coincidental?
Terry, 230RN
* Come to think of it, ETA, tight "beams" wouldn't even be necessary if you could get the intereference patterns to match at a specific locale. But I didn't want to revise the whole post.