The general idea is to set up a supersonic flow of atoms within the BEC. Sound waves moving against this flow can never make any ground. So the region where the flow changes from subsonic to supersonic is an event horizon. Any sound waves (or phonons) created inside the event horizon can never escape because the flow there is supersonic. That's the black hole.
Lahav and co set up a supersonic flow by creating a deep potential well in the middle of a BEC that attracts atoms. The atoms stream into it but cannot give up their energy when they arrive (they're already in their lowest energy state), and so they stream across the well at supersonic speed.
The result is a region within the BEC in which the atoms move at supersonic speed. This is the black hole: any phonon unlucky enough to stray into this region cannot escape.
But there are some notable exceptions. And to be clear, by "ineffective" I mean they perform no better than a placebo. I expect this research will be used as part of the government's plan to pay for the most effective and most cost-effective treatments with our upcoming public health plan.
Echinacea for colds. Ginkgo biloba for memory. Glucosamine and chondroitin for arthritis. Black cohosh for menopausal hot flashes. Saw palmetto for prostate problems. Shark cartilage for cancer. All proved no better than dummy pills in big studies funded by the National Center for Complementary and Alternative Medicine. The lone exception: ginger capsules may help chemotherapy nausea.
As for therapies, acupuncture has been shown to help certain conditions, and yoga, massage, meditation and other relaxation methods may relieve symptoms like pain, anxiety and fatigue.
However, the government also is funding studies of purported energy fields, distance healing and other approaches that have little if any biological plausibility or scientific evidence.
What to most of us seems like a short stretch of time would drag unbearably for someone with ADHD, says Katya Rubia of the Institute of Psychiatry at King's College London. Her team's research, reported this week, adds to a growing body of evidence for the importance of time perception in a wide range of psychological disorders.
ADHD affects around 5 per cent of children globally, most of them boys. Studies relating to the disorder have focused on patients' short attention spans and impulsive behaviour. But ADHD is characterised by a shortage of dopamine, which is known to affect time perception, so Rubia and her colleagues wanted to know if this was the source of the kids' problems.
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