Forty-five years after her first UCLA teaching gig attracted the wrath of Gov. Ronald Reagan , Angela Y. Davis is back on campus this semester, as regents’ lecturer in the gender studies department. Her Thursday address in Royce Hall, about feminism and prison abolition, sums up some but not all of her work — a long academic career paralleled by radical activism. President Nixon called her a “dangerous terrorist” when she was charged with murder and conspiracy after a deadly 1970 courthouse shootout. She was acquitted, and since then, the woman born in the Jim Crow minefield of Birmingham, Ala., has written, taught and lectured around the world. Her iconic Afro has morphed from its 1970s silhouette; her intensity has not.