Consider the following premises. u <-> q_8. ~u. u_3 or s_1. u_3 <-> q_8. Can we infer s_1 from them?
 From u <-> q_8, ~u we can infer ~q_8. From u_3 <-> q_8, ~q_8 we can infer ~u_3. Finally, from u_3 or s_1, ~u_3 we can infer s_1. Therefore, the answer is yes.