Casual Pot Use Causes Brain Abnormalities

This Chicago Tribune article entitled "Casual Pot Use Causes Brain Abnormalities in Young: Study" reports on a recent research study revealing that even with casual use, there is a direct correlation between the number of times young users smoked and brain abnormalities, especially in the nucleus accumbens and the nucleus aygdala. These are two areas which regulate emotion and motivation. Is there any "safe" level of pot smoking? What are the implications, especially if people use medical marijuana?

Diet’s Link to Longevity: After 2 Studies Diverge, a Search for Consensus

The NY Times article entitled "Diet’s Link to Longevity: After 2 Studies Diverge, a Search for Consensus" discusses the conflicting result on Caloric Restriction as a way to prolong lifespan between two research studies. What do you think about the way they are trying to resolve the conflicting results? Does caloric restriction seem a logical way to lengthen lifespan to you?