Weighing factors in obesity
In “Obesity research gets weightier” (SN: 12/29/12, p. 28) Nathan Seppa says that green space and a nearby grocery store reduce the incidence of obesity. I think I understand how the green space affects it (clean air, physical activity, et cetera), but I don’t understand how the grocery store does. Is there anything showing a connection?
Ted Grinthal, Berkeley Heights, N.J.

The connection lies in access to fresh fruits and vegetables, which fight obesity. The researchers counted grocery stores that sold fruits and veggies within a half mile of neighborhoods (a positive) and fast-food shops in that radius (a negative). These yielded a nutrition score, which was combined with a physical activity score. Obesity rates in kids were 59 percent lower in neighborhoods that scored well on both, even after accounting for race, income and other factors. “If we want to reduce the obesity epidemic,” says Lawrence Frank of the University of British Columbia in Vancouver, “we need to reverse the way we’re building our communities.” — Nathan Seppa

Science as an ongoing process
Debunked Science” (SN: 12/29/12, p. 31) was a welcome addition to your year-end issue. While your magazine has stressed that its reported findings are just a part of the scientific process of discovery, it is important and refreshing to see follow-up research that may reach alternate or contradictory conclusions.
Roger C. Tollefsen, Hampton Bays, N.Y.

The article “Gulf Stream may melt methane”(SN: 12/1/12, p. 12)says that changes in the Gulf Stream have heated “sediments in a strip along the North Atlantic seafloor by 8 degrees Celsius.” The 8 degree rise actually refers to the maximum observed rise in ocean temperature, which occurs at 500 meters water depth. Any sediments at those depths could experience similar heating from the overlying water.

A graphic in the article “ Light in the dark ” ( SN: 1/12/13, p. 18 ) showed the Earth revolving around the sun in a clockwise direction as seen from above the North Pole, but should have depicted a counterclockwise direction. The corrected graphic is shown above.