The average-density approximation is used to construct a nonlocal kinetic energy functional for an inhomogeneous two-dimensional Fermi gas. This functional is then used to formulate a ThomasFermi von Weizsäcker-like theory for the description of the ground state properties of the system. The quality of the kinetic energy functional is tested by performing a fully self-consistent calculation for an ideal, harmonically confined, two-dimensional system. Good agreement with exact results are found, with the number and kinetic energy densities exhibiting oscillatory structure associated with the nonlocality of the energy functional. Most importantly, this functional shows a marked improvement over the two-dimensional Thomas-Fermi von Weizsäcker theory, particularly in the vicinity of the classically forbidden region.

Almost all students had serologic evidence of protection against hepatitis B virus infection; most were vaccinated as adolescents and were tested more than 10 years after vaccination. Among students with anti-HBs concentrations of less than 10 IU/L, nearly all had 10 IU/L or more after at least 1 additional vaccine dose.