In Brief

Air force demotes Playboy poser A US Air Force sergeant who posed nude for Playboy magazine has been removed from active duty and demoted from staff sergeant to senior airman.

The move reverts Michelle Manhart to air national guard status, a move which has prompted her resignation, she says. “I’m disappointed in our system.They went too far with it,” she told AP.Manhart appeared in the Playboy’s February edition in a range of poses, some in uniform and striking a military pose, others while naked.Manhart had been a member of the Iowa air national guard before going on extended active duty with the air force.* Egyptian Brotherhood mass arrests The opposition Islamist group in Egypt, the Muslim Brotherhood, says at least 73 of its members have been arrested in overnight raids across the country.Security sources said those held were detained for belonging to an illegal organisation and for possessing anti-government literature.The Muslim Brotherhood is outlawed in Egypt but is normally tolerated.The group says the arrests are a pre-emptive move ahead of April’s vote for the upper house of parliament.The raids came days after one of the Brotherhood’s most senior figures, Khayrat al-Shatir, was ordered to stand trial in a military court on charges of money-laundering and financing an illegal group.* Light is shed on darkest galaxies The mystery of how the darkest galaxies in the Universe came to exist may have been solved by scientists.Dwarf spheroidals are galaxies composed almost entirely of dark matter; faint examples have been discovered orbiting the Milky Way and Andromeda galaxies.Scientists believe these dark systems were once gas-rich, but as they became satellites of larger galaxies, most of their visible matter was stripped away.The study, reported in the journal Nature, may shed light on dark matter.The scientists used computer simulations to uncover what might have happened 10 billion years ago as a gas-dominated dwarf galaxy hurtled into the orbit of a larger, Milky-Way-sized system.They found the drag force, or “ram pressure”, created as a smaller galaxy moved through the more massive one would have stripped away the dwarf galaxy’s interstellar gas.BBC”I’m disappointed in our system.They went too far with it,” she told AP.Manhart appeared in the Playboy’s February edition in a range of poses, some in uniform and striking a military pose, others while naked.Manhart had been a member of the Iowa air national guard before going on extended active duty with the air force.* Egyptian Brotherhood mass arrests The opposition Islamist group in Egypt, the Muslim Brotherhood, says at least 73 of its members have been arrested in overnight raids across the country.Security sources said those held were detained for belonging to an illegal organisation and for possessing anti-government literature.The Muslim Brotherhood is outlawed in Egypt but is normally tolerated.The group says the arrests are a pre-emptive move ahead of April’s vote for the upper house of parliament.The raids came days after one of the Brotherhood’s most senior figures, Khayrat al-Shatir, was ordered to stand trial in a military court on charges of money-laundering and financing an illegal group.* Light is shed on darkest galaxies The mystery of how the darkest galaxies in the Universe came to exist may have been solved by scientists.Dwarf spheroidals are galaxies composed almost entirely of dark matter; faint examples have been discovered orbiting the Milky Way and Andromeda galaxies.Scientists believe these dark systems were once gas-rich, but as they became satellites of larger galaxies, most of their visible matter was stripped away.The study, reported in the journal Nature, may shed light on dark matter.The scientists used computer simulations to uncover what might have happened 10 billion years ago as a gas-dominated dwarf galaxy hurtled into the orbit of a larger, Milky-Way-sized system.They found the drag force, or “ram pressure”, created as a smaller galaxy moved through the more massive one would have stripped away the dwarf galaxy’s interstellar gas.BBC