The measurements of hadron and lepton-pair production cross sections and le
ptonic forward-backward asymmetries performed with the L3 detector at centr
e-of-mass energies between 130 GeV and 189 GeV are used to search for new p
hysics phenomena such as: contact interactions, exchange of virtual leptoqu
arks, scalar quarks and scalar neutrinos, effects of TeV strings in models
of quantum gravity with large extra dimensions and non-zero sizes of the fe
rmions, No evidence for these phenomena is found and new limits on their pa
rameters are set. (C) 2000 Elsevier Science B.V. All rights reserved.