Soot polluting, warming Arctic

Soot spewed from South Asian factories is getting lofted into the upper atmosphere, ending up at the North Pole. When the soot falls on ice, it darkens its surface. This causes the snow to absorb more sunlight, which increases melting. Scientists have recently shown this may be having a significant warming impact on the Arctic, by accelerating the melting of sea ice and raising atmospheric temperatures. Soot is produced during burning, when there is not enough oxygen to ensure complete combustion. South Asia is the source of about a third of all the soot; another third comes from burning vegetation around the world and the remainder from Europe, Russia, and North America.

-Mike Ghenu
Source: NASA

Virginity pledges do not prevent STDs: study

A new study says that adolescents who take “virginity pledges” (oaths to abstain from intercourse before marriage) are just as likely to contract an STD before marriage compared to non-pledgers. Virginity pledges first became popular in the US in the early 1990s as a way to promote abstinence. By 1995 two million teenagers had taken a pledge. In 1995 the US federal government founded the National Longitudinal Study of Adolescent Health, an eight-year series of interviews with 20,000 adolescents, 20 per cent of which had pledged. After analyzing the data from this survey, Columbia and Yale researchers have published their findings. They say that pledgers started having sex later (by about a year to 18 months), married earlier, and had fewer sexual partners than non-pledgers-but they had equal rates of STDs by the time they were married. The researchers say this is because pledgers are less likely to use condoms when they begin having sex compared to non-pledgers. They are also less likely to seek diagnosis or treatment for their STDs. Moreover, pledgers were more likely to have anal or oral sex before engaging in vaginal sex-among “virgins,” male pledgers were four times more likely to have had anal sex compared to non-pledged virgins. Both male and female virgins were six times more likely to have engaged in oral sex compared to non-pledged virgins. Researchers say that pledgers engaging in “riskier” behaviour to preserve their technical virginity would also put them at high risk for STDs.

-Zoe Cormier
Source: Washington Post