New Delhi, Jan 16 : President-elect Barack Obama's `Call for Community Service' appears to have had a huge impact on most of the celebrities, as many of them have vowed to adopt positive changes in their daily living.

Remarkably, more than 50 Hollywood celebrities have pledged to take positive action, in a video from husband-and-wife duo Ashton Kutcher and Demi Moore.

The video will premiere on social networking website MySpace. com, one day before Obama''s inauguration.

Recent studies revealed that women should take break from work before and after birth of the baby.

In first study, Sylvia Guendelman, professor of maternal and child health at UC Berkeley''s School of Public Health and her collogues found that women who took leave before they gave birth were almost four times less likely to have a primary C-section as women who worked through to delivery.

Washington, Jan 16 : Pakistan has admitted that US drone attacks on its tribal areas bordering Afghanistan have become more accurate in past few months, leading to the death of eight ai Qaeda militants and decline in civilian casualties.

Among those killed was the mastermind of a 2006 plot to detonate liquid explosives aboard planes flying across the Atlantic, and the man thought to have planned the Septembr 20 bombing of the Marriott hotel in Islamabad, that killed 53 people, including two members of the US military.

"The strikes have become increasingly accurate," The Washington Times quoted a senior Pakistani official, as saying on the condition of anonymity because of the sensitive nature of the subject.

Washington, January 16 : A team of Duke University engineers has produced a new type of cloaking device, which is significantly more sophisticated than a prototype they unveiled in 2006 at cloaking in a broad range of frequencies.

The researchers attribute this breakthrough to the development of a new series of complex mathematical commands, known as algorithms, which helped them guide the design and fabrication of exotic composite materials known as metamaterials.

Washington, Jan 16: In a first ever estimate, a study has determined that the total fish biomass in the world's oceans is about two billion tonnes.

A team of international scientists, which included University of British Columbia fisheries researcher Villy Christensen, conducted the study.

It was also discovered that fish play a previously unrecognized but significant role in mitigating climate change by maintaining the delicate pH balance of the oceans.

Washington, Jan. 16 : An expert on South Asian affairs has claimed that the defeat of extremist forces in South Asia has not succeeded fully due to Pakistan's ambivalence toward religious militancy, and on its reliance in the past to achieve its aims in Afghanistan and India.