More than 34 percent of American adults — about 72 million people — are obese or overweight, according to the Centers for Disease Control and Prevention. Scientists once hoped leptin, a hormone that sends the body chemical signals to stop eating and use stored energy, would be a weight-loss weapon.

Studies in thin animals looked promising but overweight animals and people didn’t respond the same way, likely because their bodies already overproduce leptin, causing them to develop resistance to the hormone.

But now University of Florida researchers say pairing leptin with just a minor amount of exercise seems to revive the hormone’s ability to fight fat again.

Clouds have typically posed a problem to scientists using satellites to observe the lowest part of the atmosphere because they block the satellite's ability to capture a clear, unobstructed view of Earth's surface.

But these "obstructions" are worth a closer look, as clouds and their characteristics actually serve a valuable role in Earth's climate. That closer look is now available by satellites comprising the Afternoon Constellation, or A-Train.

The five satellites – NASA's Aqua, Aura, CloudSat and CALIPSO and the French Space Agency's PARASOL – of the A-Train orbit only eight minutes apart and can be thought of as an extended satellite observatory, providing unprecedented information about clouds, aerosols and atmospheric composition.

ESO's VLT has allowed astronomers to determine that WOH G64, a red supergiant star almost 2,000 times as large as our Sun located 163,000 light-years away in the Large Magellanic Cloud, weighs almost half of what was previously thought, thereby solving the mystery of its existence.

The behemoth star is found to be surrounded by a massive and thick torus of gas and dust, and is most likely experiencing unstable, violent mass loss.

"Previous estimates gave an initial mass of 40 times the mass of the Sun to WOH G64. But this was a real problem as it was way too cold, compared to what theoretical models predict for such a massive star. Its existence couldn't be explained," says Keiichi Ohnaka, who led the work on this object.

In 2001, the DNA sequence was published of a combination of persons. The DNA sequences of Jim Watson, discoverer of the DNA’s double helix structure, followed in 2007, and later the DNA of gene hunter Craig Venter. Recently the completion of the sequences of two Yoruba Africans was announced.

Now geneticists of Leiden University Medical Centre (LUMC) in The Netherlands have determined the first DNA sequence of a woman - and also the first European. This has been announced by the researchers this morning, during a special press conference at ‘Bessensap’, a yearly meeting of scientists and the press in the Netherlands.

Following in-depth analysis, the sequence will be made public, except incidental privacy-sensitive findings. The results will contribute to insights into human genetic diversity.

Who is Marjolein Kriek?

When patches of red, flaky and itchy skin on newborn mice led rapidly to their deaths, researchers at Washington University School of Medicine in St. Louis looked for the reason why. What they found was a molecular alarm system that serves as a sentinel to monitor the integrity of skin — the body's essential protective barrier.

The fatal effects of raising this alarm in the lab mice suggests generally that certain kinds of impairments to the skin's structure can potentially trigger harmful effects in other areas of the body, according to the researchers.

The research team found that the mice's irritated skin produced an alarm signal in the form of a natural inflammatory substance called TSLP (thymic stromal lymphopoietin), which launched a massive overproduction of white blood cells and ultimately killed the mice.

There was no significant increase in the prevalence of obese children and teens in the U.S. between 1999 and 2006, in contrast to the increase that had been reported in prior years, according to a study in the May 28 issue of JAMA.

“In the United States, the prevalence of overweight among children increased between 1980 and 2004, and the heaviest children have been getting heavier,” the authors write.

Cynthia L. Ogden, Ph.D., of the Centers for Disease Control and Prevention (CDC), Hyattsville, Md., and colleagues updated the most recent national estimates of the prevalence of pediatric high body mass index (BMI). Height and weight measurements were obtained from 8,165 children and adolescents as part of the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey (NHANES), which are nationally representative surveys of the U.S. population.