A new study in Nature offers an explanation for the origin of dwarf spheroidal galaxies, one of the current puzzles in our understanding of galaxy formation.

Dwarf spheroidal galaxies are small and very faint, containing few stars relative to their total mass. They appear to be made mostly of dark matter - a mysterious substance detectable only by its gravitational influence, which outweighs normal matter by a factor of five to one in the universe as a whole.

Isaac Asimov's Three Laws of Robotics were immortalized in the short story "Runaround" in 1942.   In it he formalized the rules that all positronic robots must obey.

Two engineers think Asimov's laws need an update.

Scientists have been thinking increasingly about whether or not animals in the ocean might play a role in larger-scale ocean mixing, says John Dabiri, a Caltech bioengineer. Ocean mixing is the process by which various layers of water interact with one another to distribute heat, nutrients and gasses throughout the oceans.

"The perspective we usually take is how the ocean--by its currents, temperature, and chemistry--is affecting animals," says Dabiri, who, along with graduate student Kakani Katija, discovered the new mechanism.

The number of large-diameter trees that Yosemite National Park is famous far are on the decline, and warmer temperatures appear to be the culprit.

Their number have declined 24 percent in the park between the 1930s and 1990s. Scientists from the U.S. Geological Survey and University of Washington compared the earliest records of large-diameter trees densities from 1932 to the most recent records from 1988.

The number of large-diameter trees that Yosemite National Park is famous far are on the decline, and warmer temperatures appear to be the culprit.

Their number have declined 24 percent in the park between the 1930s and 1990s. Scientists from the U.S. Geological Survey and University of Washington compared the earliest records of large-diameter trees densities from 1932 to the most recent records from 1988.

Professor Wei Sha from Queen’s University Belfast’s School of Planning, Architecture and Civil Engineering is concerned with the combat safety of vehicles that use titanium alloys.

Obviously the best way to remain safe is to actually not be at war but since bullets are flying and  terrorists are blowing themselves up, he has examined the damage tolerance of the popular material titanium.   The UK military based in Afghanistan currently use land rovers which have titanium alloys.   It is the first research of its kind to reveal the reasons behind the deformation and damage of titanium alloys under strong impact or fast applied force.