Washington, Oct 17 : Astronomers have discovered a new class of pulsars that emit gamma rays, which would open a new window on the evolution of stars.

One such object was discovered by the Large Area Telescope (LAT) onboard NASA''s Fermi Gamma-ray Space Telescope, a collaboration with the U. S. Department of Energy (DOE) and international partners.

About three times a second, the 10,000-year-old pulsar sweeps a beam of gamma-rays toward Earth, and is the first one known to "blink" only in gamma rays.

"This is the first example of a new class of pulsars that will give us fundamental insights into how stars work," said Stanford University''s Peter Michelson, principal investigator for the LAT.

Washington - Ice in the Arctic summer sea has been melting at almost record levels amid general temperature increases, according to an expert report released late on Thursday.

The review by the US National Oceanic and Atmospheric Administration (NOAA) warns that the Arctic's continued warming shows the dramatic effects of climate change even more than other regions.

Autumn air temperatures were a record 5 degrees Celsius above normal due to the amount of sea ice lost in recent years, according to the report.

Washington, Oct 17 : A genetic study of a fish that lives in the icy waters off Antarctica sheds light on the adaptations that enable it to survive in one of the harshest environments on the planet.

The study is the first to search the genome of an Antarctic notothenioid fish for clues to its astounding hardiness.

There are eight families of notothenioid fish, and five of them inhabit the Southern Ocean, the frigid sea that encircles the Antarctic continent.

These fish can withstand temperatures that would turn most fish to ice. Their ability to live in the cold – and oxygen-rich – extremes is so extraordinary that they make up more than 90 percent of the fish biomass of the Southern Ocean.

Washington, Oct 17 : A new study in mice has suggested that several genes that play a role in how human body''s cells normally auto-destruct may play a role in age-related hearing loss.

While more than 100 genes are known to play a role in congenital deafness, scientists have yet to pinpoint any gene in humans that plays a role in presbycusis, or age-related hearing loss.

"It''s very likely that multiple genes contribute to age-related hearing loss. We know the same is true for other diseases, for instance some types of cancer and heart disease," said Robert D. Frisina, Ph. D., the lead investigator and professor of Otolaryngology at the University of Rochester Medical Center.

Washington - The US presidential candidates put aside the serious business of courting voters Thursday night to match wits before a well-heeled crowd that expected to be entertained, not wooed.

Dressed in a white tie and black dinner jacket, Republican John McCain, 72, insisted he had dismissed his entire team of senior advisors and replaced them with "a man named Joe the Plumber" - a reference to an Ohio man who has become Everyman in the bitter race for the White House.

London, Oct 17 : Dramatic images taken at least every six hours over an entire year, using time-lapse technique, reveal how the world’s fastest-flowing glacier is draining Greenland’s ice sheet and contributing to sea-level rise world-wide.