Washington, Apr. 21 : Raising concerns over the increasing writ of the Taliban in Pakistan, the United States has urged the international community to join hands to counter the insurgents' dangerous ambitions.

"They''re a threat to democracy and stability in the region, and we call on all those who are interested in bringing about stability to that region to work with us to root out violent extremism," US State Department spokesperson Robert Wood said.

Washington, Apr. 21 : Former US Vice President Cheney has taken umbrage over the selective release of CIA-related interrogation techniques by the Obama administration that showed the Bush administration in poor light, and officially demanded that all CIA memos relating to the subject be declassified to show the positive results of the techniques.

Washington, April 21 : Scientists at the Cambridge University, UK, have discovered that freshwater algae can form stable groupings in which they dance around each other, resembling forms like waltz and minuet.

The researchers studied the multicellular organism Volvox, which consists of approximately 1,000 cells arranged on the surface of a spherical matrix about half a millimetre in diameter.

Washington, Apr. 21: President Obama greeted each member of the White Sox team during their tour of the White House on Monday.

Octavio Dotel, a relief pitcher from the Dominican Republic, asked for -- and received -- a hug instead of a handshake from Obama.

Washington, Apr. 21 : The Obamas are out to make new traditions at the White House, and helping them out this endeavour is their social secretary Desiree Rogers, Valerie Jarrett, a White House senior adviser, and Susan Sher, associate counsel and adviser to US First Lady Michelle Obama.

Since President Obama was sworn in on January 20 this year, the social office at the White House has run more than 60 events, with the Easter Egg Roll last week the most recent, a tradition on the South Lawn since 1878.

Washington, April 21 : Scientists at Harvard University, US, have found that tropical cyclones readily inject ice far into the stratosphere, possibly feeding global warming.

The finding provides more evidence of the intertwining of severe weather and global warming by demonstrating a mechanism by which storms could drive climate change.

Many scientists now believe that global warming, in turn, is likely to increase the severity of tropical cyclones.