This week's broadcast, hosted by Jane Pauley, features Tony Dokoupil's report on a new theory to address severe food allergies. Also: Martha Teichner talks with character actor Sam Elliott, nominated for an Oscar for "A Star Is Born"; Tracy Smith profiles singer Linda Ronstadt; Serena Altschul visits "Sesame Street," which will soon mark 50 years on television; Seth Doane checks out a Madrid workshop where facsimiles of ancient treasures are crafted with high tech tools; and Luke Burbank pays a visit to a Southern institution: the Waffle House
