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This paper gives the results of a study of single-pion production by the weak charged current utilizing the wide-band muon-type-neutrino beam at the Argonne Zero Gradient Synchrotron. The data were obtained from hydrogen and deuterium fillings of the 12-ft bubble chamber. The methods of event selection and separation from background are given as are the details of the corrections and systematic effects in the data sample. The energy-dependent cross sections and differential distributions are presented for the three single-pion production reactions vp -p p y + , vn +p and vn -p -n r f . An isospin decomposition shows that the ratio of I = , to I = amplitudes is 0.68k0.04 with a relative phase of (90.7k4.6)" for M ( N a ) < 1.4 GeV. This agrees with theoretical models, particularly the detailed calculation of Adler. Using the data of the reaction vp -p-pa+, the characteristic mass of the nucleon axial-vector elastic form factor is measured to be 0.98' ::;GeV when analyzed within the context of the Adler model. The data are also compared to other parametrizations of the nucleon axial-vector form factor. 1161

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New Jefferson Lab data are presented on the nuclear dependence of the inclusive cross section from (2)H, (3)He, (4)He, (9)Be and (12)C for 0.3 < x < 0.9, Q(2) approximately 3-6 GeV(2). These data represent the first measurement of the EMC effect for (3)He at large x and a significant improvement for (4)He. The data do not support previous A-dependent or density-dependent fits to the EMC effect and suggest that the nuclear dependence of the quark distributions may depend on the local nuclear environment.