A British study has confirmed something that parents have known all along: too much TV or computer use is harmful to kids.  Researchers used 1.013 kids aged 10 and 11 for this study, measuring how much time they spent on the computer and watching the boob tube.  The subjects also wore an accelerometer around their waists for a week to measure their physical activity and down time.  In addition, the children filled out questionnaires about their behavior patterns, emotional difficulties, and hyperactivity levels.  As a result, the study concluded that more than two hours a day of watching television or using a computer is associated with emotional difficulties, and no amount of physical activity can offset that time spent in front of a screen.