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Brown bears on an Alaskan archipelago are the descendants of an ancient polar bear population rather than being the ancestors of modern polar bears, new research published in PLOS Genetics shows.

Scientists have long struggled to understand the exact nature of the evolutionary relationship between brown bears and their arctic descendants. It is known that these two species can mate successfully in captivity and in the wild, but how much of their genetic histories are the result of past interbreeding has remained a puzzle.

Daejeon, Republic of Korea, March 15, 2013 -- A research team from the Korea Advanced Institute of Science and Technology (KAIST) released their results on the structure and molecular details of the neurodegenerative disease-associated protein Ataxin-1. Mutations in Ataxin-1 cause the neurological disease, Spinocerebella Ataxia Type 1 (SCA1), which is characterized by a loss of muscular coordination and balance (ataxia), as is seen in Parkinson's, Alzheimer's, and Huntington's diseases.

PHILADELPHIA - Seasonal epidemics of influenza result in nearly 36,000 deaths annually in the United States, according to the Centers for Disease Control. Current vaccines against the influenza virus elicit an antibody response specific for proteins on the outside of the virus, specifically the hemagglutinin (HA) protein.

Scientists are a step closer to developing vaccines for a range of diseases that affect 200 million people, mainly in tropical south-east Asia, Africa and Central America.

Researchers studying infections caused by parasitic worms – which can lead to diseases such as elephantiasis and river blindness – have shown how these can shut down a part of the immune system that might otherwise fight sickness. Preventing this immune reaction enables the infection to persist, causing chronic illness.

SAN DIEGO – Three studies released today present possible positive news for people with Parkinson's disease. The studies, which will be presented at the American Academy of Neurology's 65th Annual Meeting in San Diego, March 16 to 23, 2013, report on treatments for blood pressure problems, the wearing-off that can occur when people have taken the main drug for Parkinson's for a long time, and for people early in the disease whose symptoms are not well-controlled by their main drugs.

OAKLAND, Calif., March 14 — Patients who consume high-fat dairy products following breast cancer diagnosis increase their chances of dying from the disease years later, according to a study by Kaiser Permanente researchers.

The study, published in the Journal of the National Cancer Institute, is the first to examine the relationship between high-fat and low-fat dairy consumption following a diagnosis of breast cancer and long-term breast cancer survival.

While poverty and under-education continue to dampen contraception use in Nepal, exacerbating the country's efforts to reduce maternal and child mortality rates, researchers say another, more surprising factor may be more intractable: Deeply held cultural preferences for sons over daughters.

For deer mice living in the Nebraska Sandhills, color can literally be the difference between life and death.

When they first colonized the region, the dark-coated mice stood out starkly against the light-colored, sandy soil, making them easy prey for predators. Over the next 8,000 years, however, the mice evolved a new system of camouflage – lighter coats, changes in the stripe on their tails and changes in the extent of pigment across their body – that allowed them to blend into their new habitat.

COLUMBUS, Ohio – Researchers have identified an elusive anti-cancer property of vitamin E that has long been presumed to exist, but difficult to find.

Many animal studies have suggested that vitamin E could prevent cancer, but human clinical trials following up on those findings have not shown the same benefits.

DARIEN, IL – A new study suggests that the bladder condition nocturia may worsen the already poor sleep of older adults with insomnia.

"The results raise the clinical question of treating nocturia to help individuals with insomnia," said Jamie Zeitzer, PhD, the study's lead author. "That is, could much of the insomnia or poor sleep that occurs in older individuals be alleviated by treatment of nocturia? Of course, the opposite is quite possible – that proper treatment of insomnia might reduce the occurrence of nocturia as well."

Geoengineering, the use of human technologies to alter the Earth's climate system — such as injecting reflective particles into the upper atmosphere to scatter incoming sunlight back to space — has emerged as a potentially promising way to mitigate the impacts of climate change. But such efforts could present unforeseen new risks. That inherent tension, argue two professors from UCLA and Harvard, has thwarted both scientific advances and the development of an international framework for regulating and guiding geoengineering research.

The core drill slides through a drill pipe, extending from the drill ship at the sea surface, through a water depth of 2.5 km and hundreds of metres of sediment, into the oceanic crust off the west coast of North America. Microbiologist Mark Lever is on board the Integrated Ocean Drilling Program's research vessel JOIDES Resolution to examine rock samples from the depths. The results of the studies he and his colleagues carried out are published today in the journal Science.

A healthy adult must generate as many as one hundred billion new red blood cells each day, to maintain the numbers circulating in his blood. A team of EPFL researchers has identified a key step in the process by which red blood cells are born. The discovery could not only shed light on the causes of blood disorders such as anaemia, it could also bring closer the medics' dream of being able to manufacture red blood cells in the lab—thus providing a potentially inexhaustible supply of an essential component of blood for transfusion.

Cambridge, Mass. – March 14, 2013 – Geoengineering, the use of human technologies to alter the Earth's climate system — such as injecting reflective particles into the upper atmosphere to scatter incoming sunlight back to space — has emerged as a potentially promising way to mitigate the impacts of climate change. But such efforts could present unforeseen new risks. That inherent tension, argue two professors from UCLA and Harvard, has thwarted both scientific advances and the development of an international framework for regulating and guiding geoengineering research.

Ann Arbor, Mich. — Few situations can provoke more anxiety for people with peanut or tree-nut allergies than having an allergic reaction while flying on an airplane and being unable to get help.

But in a new study, published in the Journal of Allergy and Clinical Immunology-In Practice, researchers found passengers who engaged in eight mitigating factors were less likely to report an allergic reaction.