THE HANS INDIA |
Nov 17,2017 , 12:11 AM IST
Cuban and foreign experts have offered scientific evidence denying the alleged "acoustic attacks" on the US diplomatic personnel in the island, an incident which has harmed the relations between the two former Cold War foes. According to the US State Department, 24 diplomats on the island were harmed by the alleged acoustic attacks which caused hearing loss, dizziness, fatigue and cognitive issues.
The foreign experts said it is impossible to link any of the symptoms to acoustic attacks and that the lack of evidence provided by Washington makes it harder to find a scientific explanation to the incidents.
Here are some examples of devices, CNN reports, that use sound to disperse or attack: Long-range acoustic devices: Since the early 1990s, long-range acoustic devices -- also known as LRADs -- have helped authorities control crowds of people, especially protesters.
They emit a loud, painful sound over a long distance and make people run away; 'Mosquito': The so-called "mosquito" produces a very high-pitched sound that can be perceived by teenagers, but not to adults. It's used in several countries to prevent people from loitering; Infrasonic devices: Infrasound doesn't need to be heard for it to work.
Since the 1990s, the US military and private companies researched infrasonic devices that could cause behavior changes at frequencies too low to be audible; Ultrasound devices: Like infrasound, ultrasound is not audible. Jürgen Altmann, a physics professor at Technischen Universität Dortmund in Berlin, said it's not clear what type of device -- if any -- may have been used in Cuba; "The story is mysterious indeed," he said. But he said ultrasound devices can be challenging to use, especially if they're placed at a distance.
"One may speculate whether ultrasound (that is inaudible) was used, but projecting it over a considerable distance and/or through walls or closed windows is difficult," Altmann said; While the harm caused by most acoustic weapons is minimal, some experts say it's unclear how much of the harm is temporary pain, and how much can contribute to potential long-term hearing loss.