Cardio workouts build stronger hearts in womenThe results of a new study may help explain why women’s hearts benefit more from physical exercise than men’s hearts do. Studies in exercising male and female mice found that moderate, long-term exercise provokes a sex-dependent cardiac change that is different for females. The findings, reported at an American Physiological Society-sponsored meeting in Austin, Texas, may eventually lead to improved treatment strategies for women and men with heart disease. Dr. Sebastian Brokat and colleagues from the Center for Cardiovascular Research, Charite Berlin, had male and female mice exercise for a little more than 5 weeks and they looked for structural and“Surprisingly,” Brokat said, the females developed bigger and stronger hearts than the male mice. This type of beneficial heart enlargement or “hypertrophy” frequently occurs with exercise. It differs from pathological hypertrophy, an abnormal enlargement that leads to problems. The study also found that only the female mice experienced a 20-percent decrease in a protein that is usually found in people with heart disease. Minimum daily requirement of lead: 0 mgThe human body needs a diet enriched with many ingredients that sound less like food than like machine parts or spare change. We must have iron to capture oxygen, copper and chromium to absorb energy, cobalt to sheathe our nerves and zinc to help finger our genes. Other creatures demand the occasional sprinkling of tin, nickel, platinum, tungsten and even strontium. But when it comes to lead, the universal minimum daily requirement is zero. For humans, especially infants and young children, consumption of even moderate amounts of the metal can have serious consequences. Experiments have shown that after it infiltrates a cell, lead seeks out those regions of proteins where sulfur abounds and pushes aside smaller characters that stand in its way. But being bulkier than whatever it displaces, and chemically inappropriate besides, lead twists the entire protein into a sad, worthless shape. Social networking sites seem to have a class biasFor young people, the burning question of our time is “Facebook or MySpace?” Most often the choice is made depending on where your friends are. But what determines whether clusters of friends alight on MySpace or Facebook? A controversial answer comes from Berkeley researcher Danah Boyd: it’s social class.Boyd, who has done extensive ethnographic work on online behaviour, posted an essay sharing her findings after months of interviews, field observations and profile analysis. Generally, she contended, “The goody-two-shoes, jocks, athletes and other ‘good’ kids are now going to Facebook. These kids tend to come from families who emphasize education and going to college.” MySpace is still home for “kids whose parents didn’t go to college, who are expected to get a job when they finish high school.” She believes that there’s conscious self-identification involved in the choice. Facebookers are strivers; MySpacers are there in part because they’re rejecting the values of preppies, jocks and tools.
