If we approximate this model by a rectangular hole with infinitely high walls, the energy levels of a moving particle will be determined by the roots of Bessel functions and can be easily calculated.

Lifestyle factors, such as sleep patterns, exercise, and diet, can cause low energy levels. Medical conditions, such as low testosterone and sleep apnea, can also cause low energy levels in men.

Simply sign up to the Renewable energy myFT Digest -- delivered directly to your inbox. Green energy stocks have fallen back to levels last ... performance. For example, Danish wind turbine ...

The rest is composed of dark matter and dark energy, which are invisible but dominate the structure and evolution of the universe. Dark matter makes up most of the mass of galaxies and galaxy clusters ...