Astronomers Steve Howell of the University of California, Riverside and Thomas E. Harrison and Heather Osborne of New Mexico State University have found from their observations of over a dozen mass-losing stars in cataclysmic variables that most of the secondary stars do not appear to be normal main sequence stars in terms of their apparent abundances. To various degrees, each star seems to have low to no carbon and other odd mixtures of elements such as sodium and calcium, the astronomers announced today at the American Astronomical Society meeting in Nashville, Tenn.
An artists conception of a cataclysmic variable. Cataclysmic variables are binary stars consisting of a white dwarf primary and a lower mass secondary star.
(Artist: Mark Garlick, http://www.space-art.co.uk/, firstname.lastname@example.org)
(A main sequence star is a star that is in its normal state, such as the sun. These stars have well-defined relations between luminosity, temperature, size and mass.)
"Cataclysmic variables are binary stars consisting of a white dwarf primary and a lower mass secondary star," explained Howell. A binary star system consists of two stars orbiting about their common center of mass and held together by their mutual gravitational attraction. A white dwarf is a star that has exhausted all its nuclear fuel and has collapsed to a very small size, about the size of the Earth.
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Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.
A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...
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