As T2 goes to zero, the cold reservoir, then this goes to zero and our efficiency approaches one.

是当T2达到零，也就是低温热源，达到零度的时候,效率可以达到一。

麻省理工公开课 - 热力学与动力学课程节选

People with a sleep efficiency of less than 92 percent had a 5.5-times greater risk of developing a cold than those with a 98 percent or more sleep efficiency.

CNN: Study: Can more sleep help fight off colds?

Beijing also requires government agencies to buy energy-efficient products, and it has focused on improving building efficiency in hotels in the China's cold northern regions.

FORBES: Magazine Article

Although the assembly government can not control fuel prices or income levels, which also directly affect fuel poverty, the minister confirmed that it was offering energy efficiency advice, supporting financially through schemes such as Arbed and urging people to keep warm in the cold weather.

BBC: Sustainability questions