Tilt shift effect
Add blur to the top and bottom of the entire layer or object. Perfect to simulate a tiny world or a camera focus effect.

Blur sets how strong the blur is at the top and bottom, leaving a sharp band across the middle. Gradient blur controls how gradually the image goes from sharp to blurred: a small value gives an abrupt transition, while a large value spreads it out smoothly.
Reference
All effects are listed in the effects reference page.