Washington, March 17: While moderate physical activity is known to be beneficial to health, researchers are now suggesting people to walk 150 minutes a week, which is equivalent to 30 minutes each day 5 times a week.

Researchers at the School of Exercise and Nutritional Sciences, San Diego State University, point out that pedometers widely used as a physical activity monitoring tool are unable to measure activity intensity.

They have determined that a rate of at least 100 steps per minute achieves moderate intensity activity.

Washington, Mar. 17: President Barack Obama''s approval rating is down into the 50''s for the first time since he took office, according to a new poll by the Pew Research Center for People and the Press.

Obama has a 59 percent approval rating and a 26 percent disapproval rating in the poll, which quizzed 1,308 adults by phone (including 326 who were called on their cell phone) from March 9 to 12.

This is down from Pew''s poll last month, which showed Obama with 64 percent approval and 17 percent disapproval.

Washington, Mar. 17: The United States has decided to bar the entry of Uzi Arad, who is expected to be Israel’s new national security adviser, for nearly two years on the grounds that he is an intelligence risk.

According to the Washington Times, Arad, a former member and director of intelligence for the Mossad, Israel''s spy service, is mentioned in the indictment of Lawrence Franklin, a former Pentagon analyst who pleaded guilty in 2005 to providing classified information about Iran in a conversation with two employees of the American Israel Public Affairs Committee (AIPAC).

Washington, Mar. 17: Alaska Governor Sarah Palin will deliver the keynote address at the annual Senate-House GOP dinner to be held on June 8 at the Washington Convention Center, National Republican Senatorial Committee Chairman John Cornyn (R-Texas) and National Republican Congressional Committee Chairman Pete Sessions (R-Texas) announced on Monday.

Tehran - Tehran said Tuesday it had no knowledge of an Iranian pilotless plane reportedly being shot down by the US military over Iraq.

Foreign Ministry spokesman Hassan Ghashghavi told reporters in Tehran that he was unaware of the "vague report" on the drone that the US claimed to have shot down last month.

A US military spokesman in Baghdad said Monday that US planes destroyed an Iranian drone that had wandered deep into Iraqi airspace.

Washington, Mar 17: Scientists have uncovered where exactly lies the origin of consciousness in the brain.

While some neuroscientists have argued that consciousness may arise from a single "seat" in the brain, the new study has suggested that four specific, separate processes combine as a "signature" of conscious activity.

For the study, researchers analysed the neural activity of people who were presented with two different types of stimuli – one that could be perceived consciously, and the other that could not.

By using the above information, Dr. Gaillard of INSERM and colleagues showed that the four processes occurred only in the former, conscious perception task.