A sample of normally consolidated clay is removed from -10 m below the ground surface. The effective vertical overburden stress is 250 kPa, and Ko is 0.8. If the pore pressure parameter due to sampling is 0.7, estimate the change in pore pressure in the sample when it is removed from the clay layer. What effective stresses act on the specimen after extrusion from the sample tube? Assume the groundwater table is at the surface.