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Genetic effects of Chernobyl radiation

Researchers utilized genomic tools to investigate potential health effects of exposure to ionizing radiation, a known carcinogen, as a result of the 1986 Chernobyl accident. One study found no evidence that genetic changes associated with radiation exposure are passed to children, while the second study documented the genetic changes in the tumors of people who developed thyroid cancer after being exposed as children or fetuses to the...

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Tarantula's ubiquity traced back to the Cretaceous

Tarantulas are among the most notorious spiders, due in part to their size, vibrant colors and prevalence throughout the world. But one thing most people don't know is that tarantulas are homebodies. Females and their young rarely leave their burrows and only mature males will wander to seek out a mate. How then did such a sedentary spider come to inhabit six out of seven continents?

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How many T. rexes were there? Billions

With fossils few and far between, paleontologists have shied away from estimating the size of extinct populations. But scientists decided to try, focusing on the North American predator T. rex. Using data from the latest fossil analyses, they concluded that some 20,000 adults likely roamed the continent at any one time, from Mexico to Canada. The species survived for perhaps 2.5 million years, which means that about 2.5 billion lived...

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NASA's NICER finds X-ray boosts in the Crab Pulsar's radio bursts

A global science collaboration using data from NASA's Neutron star Interior Composition Explorer (NICER) telescope on the International Space Station has discovered X-ray surges accompanying radio bursts from the pulsar in the Crab Nebula. The finding shows that these bursts, called giant radio pulses, release far more energy than previously suspected.

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More than 5,000 tons of extraterrestrial dust fall to Earth each year

Every year, our planet encounters dust from comets and asteroids. These interplanetary dust particles pass through our atmosphere and give rise to shooting stars. Some of them reach the ground in the form of micrometeorites. An international program conducted for nearly 20 has determined that 5,200 tons per year of these micrometeorites reach the ground.

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African elephants' range is just 17 percent of what it could be

A study has both good news and bad news for the future of African elephants. While about 18 million square kilometers of Africa -- an area bigger than the whole of Russia -- still has suitable habitat for elephants, the actual range of African elephants has shrunk to just 17 percent of what it could be due to human pressure and the killing of elephants for ivory.

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Tropical species are moving northward in U.S. as winters warm

Climate change is reducing the number of sub-freezing days over much of the American South, providing an opportunity for cold-sensitive tropical species -- mammals, reptiles, amphibians, insects, trees, shrubs and grasses -- to move northward, potentially displacing temperate species. Mosquitoes could bring infectious diseases farther north. The southern pine beetle is already moving north and devastating pine forests. While some may...

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Scientists stunned to discover plants beneath mile-deep Greenland ice

Scientists found frozen plant fossils, preserved under a mile of ice on Greenland. The discovery helps confirm a new and troubling understanding that the Greenland Ice Sheet has melted entirely during recent warm periods in Earth's history -- like the one we are now creating with human-caused climate change. The new study provides strong evidence that Greenland is more sensitive to climate change than previously understood -- and at...

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How fast is the universe expanding? Galaxies provide one answer

Among the methods astronomers have found to measure the expansion rate of the local universe, the Hubble constant, surface brightness fluctuations is potentially one of the most precise. Scientists have now published the first good SBF estimate of the Hubble constant, pegging it at 73.3 km/s/Mpc: in the ballpark of other measurements of the local expansion, including the gold standard using Type Ia supernovae. The new estimate...

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Most distant quasar with powerful radio jets discovered

Astronomers have discovered and studied in detail the most distant source of radio emission known to date. The source is a 'radio-loud' quasar -- a bright object with powerful jets emitting at radio wavelengths -- that is so far away its light has taken 13 billion years to reach us. The discovery could provide important clues to help astronomers understand the early Universe.

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Did woolly mammoths overlap with first humans in what is now New England?

Woolly mammoths may have walked the landscape at the same time as the earliest humans in what is now New England, according to a new study. Through the radiocarbon dating of a rib fragment from the Mount Holly mammoth from Mount Holly, Vt., the researchers learned that this mammoth existed approximately 12,800 years ago. This date may overlap with the arrival of the first humans in the Northeast, who are thought to have arrived around...

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The right '5-a-day' mix is 2 fruit and 3 vegetable servings for longer life

Higher consumption of fruits and vegetables is associated with a lower risk of death in men and women, according to data representing nearly 2 million adults. Five daily servings of fruits and vegetables, eaten as 2 servings of fruit and 3 servings of vegetables, may be the optimal amount and combination for a longer life. These findings support current U.S. dietary recommendations to eat more fruits and vegetables and the simple...

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Gulf Stream System at its weakest in over a millennium

Never before in over 1000 years the Atlantic Meridional Overturning Circulation (AMOC), also known as Gulf Stream System, has been as weak as in the last decades. Researchers compiled proxy data, reaching back hundreds of years to reconstruct the AMOC flow history. They found consistent evidence that its slowdown in the 20th century is unprecedented in the past millennium.