Chicago – Jose Augusto Barreto-Filho, M.D., Ph.D., of the Federal University of Sergipe and the Clinica e Hospital Sao Lucas, Sergipe, Brazil, and colleagues assessed procedure rates and outcomes of surgical aortic valve replacement (AVR) among 82,755,924 Medicare fee-for-service beneficiaries between 1999 and 2011.

Kids love penguins. They sing and dance in cartoons, they waddle like Charlie Chaplin on land - but underwater, they are all business, accelerating from 0 to 15 miles per hour in less than a second. 

A normally fragile quantum state has been shown to survive at room temperature for a world record 39 minutes, overcoming a key barrier towards building ultrafast quantum computers.

In conventional computers data is stored as a string of 1s and 0s. In the experiment quantum bits of information, 'qubits', were put into a 'superposition' state in which they can be both 1s and 0 at the same time – enabling them to perform multiple calculations simultaneously. 

Messier 15 is a gathering of  100,000 very old stars that orbits the center of the Milky Way. It
is one of the densest globular clusters known, with most of its mass concentrated at its core.
 It could also hide a rare type of black hole or a collection of dark neutron stars.

Messier 15 is located 35,000 light-years away in the constellation of Pegasus, The Winged Horse). It is one of the oldest globular clusters known, with an age of around 12 billion years.

In a new Hubble image, very hot blue stars and cooler golden stars are seen swarming together, becoming more concentrated towards the cluster's bright center. 

The chemotherapy drug called cyclophosphamide prevents graft-versus-host (GVHD) disease in people who receive bone marrow transplants. New experiments point to an immune system cell that evades the toxic effects of cyclophosphamide and protects patients from a lethal form of GVHD.

The findings could pave the way for improvements in preventing GVHD and rejection of transplanted bone marrow and new therapies to prevent or treat a relapse of the underlying cancer after a transplant.

The mountain pine beetle is killing lodgepole pine and jack pine forests in the Western United States, British Columbia, the Northwest Territories, Alberta and could spread east to the Maritimes.

Yes, beetles are natural, but before you start waving Sierra Club brochures and yelling about scary science, keep in mind that nature is out to kill us all. She is, basically, a real bitch.

Researchers have been investigating pheromones emitted by the pest in North America's lodgepole and jack pine forests and tree chemical compounds that play critical roles in the beetle's pheromone production and attraction in both their established lodgepole pine host and in the newer jack pine host.

The idea is to produce scientific bait.