Washington, April 24 : Astronomers have discovered large galaxies that have not changed much in size for the last 9 billion years, which suggests these cosmic giants were born 6-7 billion years earlier than expected.

The most popular model for galaxy formation is a bottom-up or hierarchical model in which small galaxies gradually develop into larger ones over a long period of time.

The model predicts that smaller galaxies would merge to form larger ones, growing to 90 percent of their size about 11 billion years after the Big Bang.

Washington, Apr 24 : Early birds may be chirpier in the morning, but it's the night owls that score over them when it comes to being alert after waking up from sleep, concludes a new brain-scan study.

In the study, researchers monitored the brain activity of self-described early birds and night owls in a sleep lab.

Led by Christina Schmidt of the University of Liege in Belgium, the researchers also took hourly saliva samples to measure the sleepers'' levels of melatonin-a hormone thought to help naturally regulate sleep cycles in mammals.

Washington, Apr 24 : An international team of scientists has successfully sequenced cow's genome, thus paving the way for more sustainable food production.

A research team involving 300 researchers from 25 countries spent six years mapping and analysing the genetic make-up of a Hereford cow, named L1 Dominette.

The findings of this study provide the means to select animals with a smaller environmental footprint, particularly animals with less greenhouse gas emissions.

London, Apr 24 : Researchers at Seoul National University in South Korea have created the world''s first transgenic dog.

Cloned beagle named Ruppy - short for Ruby Puppy - and four other beagles all produce a fluorescent protein that glows red under ultraviolet light.

The research team led by Byeong-Chun Lee created the dogs by cloning fibroblast cells that express a red fluorescent gene produced by sea anemones, reports New Scientist.

London, April 24 : An ice collapse near the base of Mount Everest has blocked the route of scores of climbers hoping to scale the world's highest peak.

According to a report in The Daily Telegraph, no one was reported injured in the ice collapse, but the route has been blocked for a few days, Ang Tshering of the Nepal Mountaineering Association, told The Daily Telegraph.

The section of the route called the Khumbu Icefall just above the base camp is one of the riskiest areas on the way to Everest's summit.

Washington, April 24 : A new study has suggested that some coral reefs off East Africa are unusually resilient to climate change, and can be termed as `super reefs'.

The study, conducted by researchers at the Wildlife Conservation Society (WCS), showed that the reefs have become super tough due to improved fisheries management and a combination of geophysical factors.

The study found that Tanzania's corals recovered rapidly from the 1998 bleaching event that had wiped out up to 45 percent of the region's corals.