In the debate about the climate effects of carbon dioxide emissions from transportation it is assumed that fuel is the key source of pollution from vehicle traffic.

“What you seldom think about is the huge amounts of brake linings and tires that are worn out in traffic and the fact that these products contain considerable amounts of metals,” says David Hjortenkrans, one of the scientists at The University of Kalmar in Sweden who performed a new study of the issue.

Despite the fact that authorities have regulated the metal content of auto parts and the fact that the auto industry has made improvements, brake linings and tires are still among the major sources of metals in urban environments.

The organs that produce sperm also may make it easier for mutations to pass to offspring, USC biologists say. The testes in humans may act as mutation multipliers that raise the odds of passing improved DNA to offspring – but that can also backfire by increasing the frequency of certain diseases.

The new theory is part of a study, appearing in PLOS Biology, that tries to explain the puzzlingly high frequency of Apert syndrome, a genetic cranial deformity found in approximately one out of every 70,000 newborns.

The study’s authors suggest that natural selection may favor “germline” cells – the precursors to sperm – carrying a mutation that causes Apert syndrome.

In a report that is among the first to describe the prevalence of HIV and Hepatitis B and C viruses in Afghanistan, a researcher from the University of California, San Diego (UCSD) School of Medicine voiced concerns that increasing injection drug use and accompanying high-risk behavior could lead to an HIV epidemic in Afghanistan.

“Our findings suggest that interventions to reduce high-risk behaviors among injection drug users are urgently needed in Afghanistan,” said Catherine S. Todd, M.D., MPH, assistant professor in UCSD’s Division of International Health and Cross-cultural Medicine, who is currently working in Kabul, Afghanistan.

A new poisonous frog was recently discovered in a remote mountainous region in Colombia by a team of young scientists supported by the Conservation Leadership Programme (CLP). The new frog, which is almost two centimetres in length, was given the name the “golden frog of Supatá.”

Originally, the young scientists thought the frog was similar to several other common species in the area. However, after scientific analysis of the frog’s characteristics, and review of their findings by experts at Conservation International, it was determined that the golden frog of Supatá is unique and only found within a 20 hectare area in Colombia’s Cundinamarca region.

Turbulence plays an important role in Earth’s weather system, and can be more than an inconvenience - hundreds of injuries have occurred on commercial flights due to turbulence. It is studied both in Earth's atmosphere and in that of Saturn's moon, Titan, aided by data from ESA’s Huygens probe. The study of one is helping the other.

Giles Harrison, atmospheric physicist at the University of Reading in the UK, devised an inexpensive way to measure the effects of turbulence using weather balloons. The instrument package contains a magnetic field sensor which measures fluctuations in Earth’s magnetic field due to turbulence.

Dating younger women is not just about trophy wives, say the researchers behind the PLoS paper, "Why Men Matter: Mating Patterns Drive Evolution of Human Lifespan." It's also about understaning evolution.

Male reproduction begins and ends later than women’s, and declines much more gradually. In many population a fraction of men continue to father children into their 60s and 70s with younger women.