Thursday, July 03, 2014

Health and science neews

The downside of being cool

Being popular as a teenager doesn’t mean smooth sailing as an adult. In fact, a new, decade-long study found that stereotypical “cool” teens are more likely to stumble socially and have drug and alcohol problems in their 20s. “We call it the high school reunion effect,” University of Virginia psychologist Joseph Allen tells “The student who was popular and was running with the fast crowd isn’t doing as great later on.” Researchers interviewed 184 seventh- and eighth-graders to identify the “social strivers”—those who date at a young age, have good-looking friends, and are defiant of authority. Researchers also spoke with the students’ parents and friends, then followed up with them at age 22 or 23. Compared with their peers, the adult strivers had 45 percent higher rates of alcohol and drug problems and 22 percent higher rates of criminal behavior. Their ability to have positive relationships was also 24 percent lower. It may be that as cool kids get older, behaviors that once impressed their friends don’t have the same effect. So they turn to increasingly extreme measures to get attention.

How passenger pigeons died off

The extinct passenger pigeon, once the most abundant bird in the world, has long been held up as a cautionary tale of humans’ negative impact on the environment. But new research reveals that the species experienced multiple population booms and crashes in the million years prior to the last bird’s death, in 1914. Such a pattern suggests the pigeons were especially vulnerable to extinction. “If it’s already on this track,” National Taiwan Normal University biologist Chih-Ming Hung tells Science, “human influence can further increase the speed that the population goes down.” Researchers sequenced DNA from four well-preserved pigeon specimens, and then ran the data through an algorithm that used genetic diversity to extrapolate population size. The calculations showed that the birds’ numbers—estimated to have climbed to as many as 5 billion—-fluctuated up to a thousand-fold in recurring cycles throughout the species’s existence. Re-searchers also found that climate-driven shifts in the availability of acorns—one of the birds’ main foods—contributed significantly to their demise, with overhunting and human-caused deforestation eventually tipping the balance.

Earth’s hidden reservoir

The largest reservoir on Earth may be hiding hundreds of miles beneath the surface. The discovery could radically shift our understanding of how the oceans formed, indicating that water on the surface may have come from the interior of the planet—through a process called degassing—rather than from collisions with large, icy comets. The newly revealed reservoir is located in the mantle, the hot, rocky layer that separates Earth’s crust from its metallic core. Not in liquid form, the H20 is trapped inside the mineral ringwoodite, which has a crystal-like structure that makes it act like a sponge. Researchers estimate that if as little as 1 percent of the water in that reservoir were liquid, it would amount to nearly three times the volume of all the oceans on the surface. The study, which used hundreds of seismometers to create high-resolution images of the mantle, also found evidence of significant water-related rock movement at depths up to 440 miles. Such activity may influence seismic events like earthquakes and volcanic eruptions. “We’re trying to connect the rock cycles—i.e., plate tectonics—with water cycles,” Northwestern University geophysicist Steve Jacobsen tells The New York Times. “The more we look, the deeper it goes.”

Cellphones hinder fertility

Guys, take note: That cellphone in your pocket may be affecting your family jewels. A new study has found that low-level electromagnetic radiation (EMR) emitted by wireless devices hurts sperm production. Previous research suggested that the magnetic fields could be damaging sperm DNA by promoting unstable oxygen compounds. The radiation can also warm skin by about 4 degrees, which could raise the temperature of the testes enough to interfere with normal sperm production. All told, the analysis of almost 1,500 samples found, exposure to cellphone EMR lowered sperm movement by 8 percent and reduced viability by 9 percent. Researchers have yet to determine whether the level of EMR emitted by a phone or the duration of a person’s exposure are contributing factors. Still, “simply carrying your phone somewhere else doesn’t seem a too difficult thing to do,” University of Exeter researcher Fiona Mathews tells The Washington Post. Sperm counts have been dropping throughout the developed world, and about 40 percent of couples struggle with fertility issues.
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