n.

one of a pair of long straps (usually connected to the bit or the headpiece) used to control a horse

any means of control

"he took up the reins of government"

NO in exhaled air is correlated with markers of eosinophilic airway inflammation in corticosteroid-dependent childhood asthma.
The relationship between male circumcision and HIV infection in African populations.
Ab initio calculations of the quasiparticle and absorption spectra of clusters: The sodium tetramer
Effect of self-consistency on quasiparticles in solids
Rev. Mod. Phys. 74 601
Identification transponder circuit
Excitonic effects in solids described by time-dependent density-functional theory.
Ab initio GW many-body effects in graphene
Linear plasmon dispersion in single-wall carbon nanotubes and the collective excitation spectrum of graphene.
Parameter-free calculation of response functions in time-dependent density-functional theory.