Clock with 8×10^{-19} Systematic Uncertainty.

We report an optical lattice clock with a total systematic uncertainty of 8.1×10^{-19} in fractional frequency units, representing the lowest uncertainty of any clock to date. The clock relies on interrogating the ultranarrow ^{1}S_{0}→^{3}P_{0} transition in a dilute ensemble of fermionic strontium atoms trapped in a vertically-oriented, shallow, one-dimensional optical lattice.

The progression and characteristics of conceptually based fitness/wellness courses at American universities and colleges.

Objective: To describe the availability, progression, and characteristics of conceptually based Fitness/Wellness (CBFW) courses in American colleges and universities.

Participants: Surveys were completed by 161 faculty members about the availability and characteristics of CBFW courses at their particular institutions.

Methods: The CBFW course instrument was used to obtain descriptive data on courses, institutions, and availability.