Consider the following premises. For all x_12, x_12 is a scientist. James is a poet if and only if Barbara is taking a plane. For all x_12, if x_12 takes a plane, then x_12 is not a scientist. Can we infer the following from them? James is a poet.
 From the fact that for all x_12, if x_12 takes a plane, then x_12 is not a scientist, and that for all x_12, x_12 is a scientist we can infer that for all x_12, x_12 will not take a plane. From the fact that for all x_12, x_12 will not take a plane we can infer that Barbara is not taking a plane. From the fact that James is a poet if and only if Barbara is taking a plane we can infer that if James were a poet, then Barbara is taking a plane. Finally, from the fact that if James were a poet, then Barbara is taking a plane, and that Barbara is not taking a plane we can infer that James is not a poet, which contradicts that James is a poet. Therefore, the answer is no.