Ciro Santilli @cirosantilli 37

• the unperturbed ground state hyperfine transition frequency of the caesium-133 atom $\Delta v_{Cs}$ is 9 192 631 770 Hz
• the speed of light in vacuum c is 299 792 458 m/s
• the Planck constant h is 6.626 070 15 × $10^{-34}$ J s
• the elementary charge e is 1.602 176 634 × $10^{-19}$ C
• the Boltzmann constant k is 1.380 649 × $10^{-23}$ J/K
• the Avogadro constant NA is 6.022 140 76 × $10^{23}$ mol
• the luminous efficacy of monochromatic radiation of frequency 540 × 1012 Hz, Kcd, is 683 lm/W,

At Google, the preference is for working in small teams of three, with individual employees expected to allot 20 percent of their time to exploring whatever ideas interest them most. The notion of "20 percent time" is borrowed from the academic world, where professors are given one day a week to pursue private interests.