BOSTON — Young adults are earning their college degrees in Massachusetts and leaving the state, taking their eager work ethic, vitality and young families with them, according to a new study. The entire Massachusetts population has dwindled over the past 14 years, but young adults between the ages of 25 and 34 are disappearing the fastest, according to a study out of the Carsey Institute at the University of New Hampshire. And they are not just leaving the Bay State. All six New England states rank in the top 10 in the country when it comes to losing members of...