Task: Text Simplification
Input (English): in practice , however , the definition means that high-precision realizations of the second should compensate for the effects of the ambient temperature -lrb- black-body radiation -rrb- within which atomic clocks operate , and extrapolate accordingly to the value of the second at a temperature of absolute zero.
Output (English): in practice , however , the definition is that high-precision realizations of the second should compensate for the effects of the ambient temperature -lrb- black-body radiation -rrb- within which atomic clocks operate , and extend accordingly to the value of the second at a temperature of absolute zero.