Science Now
Discoveries from the world of science and medicine
Contraception, abstinence push U.S. teen birthrates to historic lows

The birthrate for American teens hit an all-time low in 2013, and government statisticians attribute the decline to a reduction in teenage sexual activity and more widespread use of birth control among those who are having sex.

Preliminary birth certificate data collected by the Centers for Disease Control and Prevention shows that 277,749 babies were born in 2013 to mothers who were under the age of 20. That is the lowest figure for any year going back to 1940, according to a report released Wednesday by researchers in the CDC’s Division of Vital Statistics. (In 1940, there were 304,004 births to American teens, the report says.)

The teen birthrate hit new lows for all age groups. There were 47.3 births for every 1,000 women ages 18 and 19; 12.3 births per 1,000 teen girls between the ages of 15 and 17; and 0.3 births per 1,000 girls ages 10 to 14. Among the 15- to 19-year-olds who accounted for nearly all teen births, the preliminary birthrate of 26.6 per 1,000 was 9.5% lower than it...

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Efforts to stop the spread of Ebola in Africa will take 'many months'

International efforts to halt the spread of Ebola in West Africa will take many more months as crushing poverty, dysfunctional health systems and widespread fear continue to fuel the epidemic, according to world health officials.

In a series of perspective pieces published Wednesday in the New England Journal of Medicine, health experts said world governments and health organizations needed to prepare for a long and focused battle against the Ebola virus.

“Stopping the outbreak at the source in Africa will take many months,” wrote Dr. Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention.

The current outbreak, which has killed at least 1,350 people, according to the World Health Organization, is the worst to occur since the virus was first identified in 1976.

The reason for this, according to Dr. Margaret Chan, director general of the WHO, is simple.

"The question can be answered with a single word," she wrote. "Poverty."

"The hardest-hit countries, Guinea,...

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Spiders get bigger when they live in the city, study finds

City living can really have its perks – if you’re a spider. Golden orb-weaving spiders that lived in urban areas were bigger and more successful than their country-dwelling counterparts, according to a team of Australian scientists.

The findings, published in PLOS One, detail the complexity of urbanization on animals that manage to survive, even thrive, in a man-made environment.

“Urbanization modifies landscapes at multiple scales, impacting the local climate and changing the extent and quality of natural habitats,” the study authors wrote. Usually it degrades those habitats and species struggle to survive, but some, like pigeons and raccoons, become “urban exploiters,” readily adapting to the new environment.

But birds and rodents are relatively large, mobile creatures, and the University of Sydney researchers wanted to see how the urbanization effect played out on small as well as large scales. They focused on Nephila plumipes, known as the golden orb-weaving spider, because these...

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Experimental drug shows promise against Ebola's cousin, Marburg virus

An experimental drug designed to halt replication of the deadly Marburg virus -- a relative of Ebola -- has proved effective in monkeys, even after they had been infected for three days, research shows. 

In a paper published Wednesday in the journal Science Translational Medicine, scientists said the intravenous drug saved the lives of 16 rhesus macaques who were injected with the virus, whereas five other monkeys who did not receive the drug died within nine days.

The experiment marks the first time a drug has been shown to protect animals following infection with the Angola strain of the Marburg virus, according to the study authors, and suggests that a similar approach may be successful in treating humans infected with Ebola.

Such an Ebola treatment, according to senior study author Thomas Geisbert, a professor of microbiology and immunology at the University of Texas Medical Branch at Galveston, could be combined with another experimental drug like ZMapp to fight the virus at...

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Confirmed: Microbial life found half mile below Antarctic ice sheet

In an icy lake half a mile beneath the Antarctic ice sheet, scientists have discovered a diverse ecosystem of single-celled organisms that have managed to survive without ever seeing the light of the sun.

The discovery, reported Wednesday in the journal Nature is not so much a surprise as a triumph of science and engineering. The research team spent 10 years and more than $10 million to prove beyond a shadow of a doubt that life did indeed exist in subglacial lakes near the South Pole.

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FOR THE RECORD

An earlier version of this post had lead author Brent Christner's names misspelled as Christener. It has been changed.

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"It's the real deal," said Peter Doran, an Earth scientist at the University of Illinois at Chicago, who was not involved in the study. "There was news that they found life early this year, but a bunch of us were waiting for the peer reviewed paper to come out before we jumped for joy."

John Priscu, the lead scientist on the project, has been...

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Study: To boost your odds of a successful marriage, have a big wedding

To improve your odds of a high-quality marriage, try not to have too many sexual partners before you meet “the one.” And when you do find him or her, consider inviting at least 150 people to your wedding. 

That’s just some of the practical advice offered by a pair of psychology researchers from the University of Denver who have studied 418 people who participated in the Relationship Development Study. All of them were single and between the ages of 18 and 40 when they joined the study in 2007 and 2008, and all of them had tied the knot by the time the researchers checked in with them five years later.

The goal was to identify patterns of behavior that tended to set people up for successful and fulfilling marriages. The researchers asked study volunteers questions about “marital happiness, confiding in one another, believing things are going well in the relationship, and thoughts of divorce,” according to their report published this week. Those who ranked in the top 40% were considered...

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Toothless 'dragon' pterosaurs once ruled skies worldwide, study says

Ancient winged reptiles called pterosaurs were so successful that they ruled Earth's skies for tens of millions of years, according to a study published in the journal ZooKeys.

The fearsome fliers, part of a family of pterosaurs named Azhdarchidae, get their name from azdarha, the Persian word for "dragon." Unlike earlier pterosaurs, they had no teeth, and they dominated from late in the Cretaceous period (around 90 million years ago) until the extinction event that also killed off the dinosaurs some 66 million years ago. 

“This shift in dominance from toothed to toothless pterodactyloids apparently reflects some fundamental changes in Cretaceous ecosystems, which we still poorly understand,” study author Alexander Averianov of the Russian Academy of Sciences wrote in the paper.

Pterosaurs are not dinosaurs, and they're definitely not ancient birds, which are the living descendants of the dinosaurs. But understanding these large predators can give insight into the ancient ecosystem as...

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Simple measures made hospital patients 70% more likely to quit smoking

A free supply of nicotine replacement medication and a handful of automated phone calls made smokers who wanted to quit much more likely to succeed, according to results of a clinical trial published Tuesday in the Journal of the American Medical Assn.

The researchers who designed the trial said they were looking for a simple and inexpensive way to aid smokers who were already motivated to kick the habit. They estimated that once their 90-day program was set up, it could be maintained at a cost of less than $1,000 per quitter.

The study involved 397 smokers who were admitted to Massachusetts General Hospital in Boston between August 2010 and November 2012. Like all hospitals in the U.S., Massachusetts General is a smoke-free facility, and smokers treated there are offered nicotine replacement therapy to help them deal with their withdrawal symptoms. Patients who want to remain smoke-free after they are discharged can get help from counselors in the hospital’s Tobacco Treatment Service....

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Rights to California surface water far greater than average runoff

California over the last century has issued water rights that amount to roughly five times the state’s average annual runoff, according to new research that underscores a chronic imbalance between supply and demand.

That there are more rights than water in most years is not news. But UC researchers say their study is the most comprehensive review to date of the enormous gap between natural surface flows and allocations.

Of 27 major California rivers, rights on 16 of them exceed natural runoff. Among the most over-allocated are the San Joaquin, Kern and Stanislaus rivers in the San Joaquin Valley and the Santa Ynez River in Southern California.

In theory, that difference is not necessarily a problem. It gives water agencies and irrigation districts with junior rights access to additional supplies during wet years, when runoff is above average and there is plenty to go around. But in reality, study co-author Joshua Viers said, it fosters unrealistic expectations for water that is often...

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Missionaries deserved access to untested Ebola drug, expert writes

They were given drugs never before used on humans, and then flown to the United States amid fears that they would spark a new outbreak of the dreaded Ebola virus.

Roughly two weeks after a pair of American missionary workers were evacuated from Liberia, debate continues over the decision to treat them with the experimental drug ZMapp, as well as their admission to a special containment ward at Emory University Hospital, in Atlanta.

In two related opinion papers published Monday in the Annals of Internal Medicine, experts wrote that fears of Ebola spreading in the United States were unfounded, and that it was reasonable to treat the infected medical workers with an experimental drug.

However, that did not necessarily mean that the same experimental drug should be used to combat the epidemic in West Africa, an author wrote.

"Ebola virus has ignited some of the worst fears in a globalized world," wrote Nancy Kass, a professor of bioethics and public health policy at Johns Hopkins...

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How a promising new drug may help combat baldness caused by alopecia

A cure for patchy baldness may be on the way, according to a new study published Sunday in the journal Nature Medicine.

Unfortunately, the treatment is expensive. It currently costs between $7,000 and $9,000 a month. And, it only treats hair loss caused by an autoimmune condition called alopecia areata. 

But for the men and women who suffer from alopecia (2% of the overall population), this could be big news.

"It is not a life-threatening form of autoimmunity, however it is a life-altering form of auto-immune disease," said Angela Christiano, a genetics specialist at Columbia University in a video describing the new research. "It affects patients in a very profound, very personal way to undergo hair loss."

People who have alopecia lose their hair in patches mostly on their scalp, but occasionally they can also lose hair from other parts of their body. Christiano suffers from alopecia herself and has been studying the disease for 15 years.

Scientists have known for decades that alopecia...

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Quasi-legal street drug poses new lethal threat to users

Emergency physicians are bracing for a new rash of overdoses of a drug that looks like heroin but may not respond to commonly used doses of the opiate-reversal drug naloxone because it is so powerful, a new study reports.

The threat comes from an emerging street drug called acetyl fentanyl -- an opiate that is five to 15 times as powerful as heroin and is being mixed with street drugs sold as heroin. An article appearing in the Annals of Emergency Medicine on Monday warns emergency physicians to expect "an upswing in what appear on the surface to be heroin overdoses" but are in fact tied to acetyl fentanyl.

Acetyl fentanyl, an analog of the prescription opiate fentanyl, has no recognized medical use. But it is not specifically regulated, and loopholes in its distribution position the drug in a legal gray area, which makes it easier to get -- and hence cheaper on the streets -- than fentanyl.

In large quantities, acetyl fentanyl can be titled, labeled and stored as a product with...

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