Scientists longing to sneak a peek at the molecular machinery of living cells came one step closer to that goal in March with the creation of lenses that break the limits of current light microscopy.
Electron microscopes can already capture the realm of the supersmall, but the sample preparation and imaging conditions make it impossible to observe live cells. Optical microscopes are great for viewing living samples, but their resolution is limited by the properties of light. Now two teams of researchers have devised unconventional lenses that could capture the nanoworld without killing it.
One group, led by Xiang Zhang of the University of California at Berkeley and Lawrence Berkeley National Laboratory, created a “hyperlens” that bends light in a way no ordinary material can. “Natural materials prevent some of the waves from coming through to the camera,” Zhang says. “You lose certain kinds of waves, called evanescent waves, which don’t travel far. That blurs the image.” But the layered structure of his half-cylinder-shaped hyperlens preserves these evanescent waves, allowing incredibly tiny objects to be resolved.
The second team, led by Igor Smolyaninov at the University of Maryland, created a “superlens” with concentric rings of acrylic on a gold film surface. The lens can be used to see objects on the scale of small viruses. “If we’re successful in this work,” Smolyaninov says, “we will hopefully be able to visualize what is going on inside cells.”
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When the dinosaurs died out some 65 million years ago, many perished in the exact same iconic pose: neck, spine, and tail curved backward, mouth open, limbs contracted. The reason for this characteristic dino death pose has been unclear. Conventional wisdom held that the dead dinos’ pose was struck when the muscles contracted under rigor mortis or because the dinos’ tendons and ligaments had dried up, suggesting that their bodies had been exposed to the sun for a long time. But if so, why hadn’t the bones been scattered by scavengers?
Now the answer is coming from the corpses of some modern-day birds and mammals, which look very similar when they have died under certain specific conditions. The connection was never made before because paleontologists rarely see dead parrots. But veterinarians do. And luckily, Cynthia Marshall Faux is both—with doctorates in veterinary medicine as well as geology (with a specialty in vertebrate paleontology).
It was clear to Faux that the dinosaurs’ pose was a sign of opisthotonos, a condition that results from an injury affecting the cerebellum, which regulates fine muscle movement. While working at the Museum of the Rockies in Bozeman, Montana, Faux collaborated with Kevin Padian, a professor of integrative biology and curator of the Museum of Paleontology at the University of California at Berkeley, to make her argument: Brain injury during death, not later rigor mortis, explains the typical look of dino fossils. “Paleontologists are familiar with dead things,” says Faux, who is a vet in Idaho. “But I know about dying things. I see animals die all the time. I see the process, not just the result.”
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Adding to the intrigue is that opisthotonos is usually seen in warm-blooded animals like birds and mammals but not reptiles. Faux’s paper on opisthotonos, published in March, rethinks dinosaurs not just as having died for reasons other than meteor impacts and volcanic eruptions but also advances the argument that these creatures may have had hot blood pumping through their veins.
Darwinian natural selection is at work among the communities living in the Tibetan mountains, according to Case Western Reserve University anthropologist Cynthia Beall. She reported at the American Association of Physical Anthropologists meeting in March that women who carry more oxygen in their blood have more than twice as many surviving children as women who carry less oxygen. “We determined that the strength of natural selection at altitude was even stronger than the strength of natural selection by falciparum malaria, and that is the classic example,” Beall said.
Women who carry at least one copy of a gene variant, or allele, that codes for high oxygen saturation had 125 percent more surviving children than those who carry two copies of a low-saturation allele. By contrast, women who carry a sickle-cell allele, which protects against malaria, have only about 50 percent more surviving children in malaria-infested regions than women lacking the variant.
Beall’s team hasn’t yet identified the gene that provides such protection, but that’s next on her agenda. In the meantime, she thinks the reason the selective difference at altitude is so large is that the altitude is constant, affecting people every day. Malaria, on the other hand, ebbs and flows over time, so the physiological benefits associated with the sickle-cell allele may be tempered.
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The mass of the new-found "X" particle which scientists have been discovering in cosmic ray research may not have a fixed value, says Dr. Seth H. Neddermeyer of the California Institute of Technology.
Dr. Neddermeyer is a colleague of Dr. Carl Anderson and worked with him when the latter made the discovery of the positron for which he received the Nobel Prize award. The team of Anderson and Neddermeyer, too, made the initial discoveries of the "X" particle, whose mass appears to be intermediate between that of the electron and the proton.
"There are . . . reasons for believing that the mass (of the X particle) may not be unique and that many masses, ranging from a few times the electron mass up to very large values, may exist," says Dr. Neddermeyer's report, in part.
By theory, explains Dr. Neddermeyer, photons of radiant energy create pairs of particles—positive and negative in electrical sign—in their rush through the atmosphere on their way to Earth. The energy and mass possessed by these new particles, which are the offspring of dying photons, are variable, postulates Dr. Neddermeyer. Thus many different masses might be observed, depending on the energy possessed by the original photon that creates them.
The point is that particles can have two kinds of mass; the so-called rest mass and a mass due to motion. Theoretically, at least, a particle moving with the speed of light should have an infinitely large mass.
The second kind of mass, which varies with the speed of the particle, was observed in the present experiments.
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Tusks scattered on the frozen shore of Siberia opposite Alaska may mean that Soviet scientists will some day add more complete specimens of the extinct hairy mammoth to the two bodies already found, Tass, Soviet news agency, reported.
Detailed information on the body, the second one to be found, reached Moscow. It revealed that this hairy mammoth, as it existed thousands of years ago, was in the neighborhood of 18 feet long, had a trunk more than 9 feet long and hair more than 3 inches long.
Like the first specimen found, the second body, which was uncovered last October, was partially damaged by wild animals. The head, one leg, and a part of the trunk have been partly eaten away. Otherwise, the body is intact, preserved through the ages in the frozen earth of the north, as effective an icebox as man has devised.
The tusks of the specimen found have not yet been located, but they may be under its body, which has not yet been removed from the pebbly ground. Next spring, when the sea in this area is clear of ice, soundings of the coastal zone will be taken to see if a ship can approach the shore to take on board the find.
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UFO investigators flock to Stephenville, Texas!
A team of six investigators from the Mutual UFO Network will be interviewing citizens of Stephenville, Texas who say they spotted an Unidentified Flying Object at sunset on January 8th.
The Mutual UFO Network is a non-governmental group interested in documenting UFO's. State director Ken Cherry says the network has received calls from 50 citizens who say they witnessed the UFO and that the number and credibility of the people is exceptional.
The rural Texas town has attracted world wide attention after the sightings. The Local Newspaper, the "Stephenville Empire-Tribune" has received calls from as far away as Finland and Japan as people remain fascinated about the reports of a giant bright object in the sky that witnesses say was a mile long.
It remains the talk of the town and the Stephenville High School Science Club is now selling T-shirts to cash in on the craze.
Stephenville prides itself on being the dairy capital of Texas and the shirts that sell for ten dollars have a picture of a Holstein cow being beamed up to a flying saucer.
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More than 30 residents of Stephenville, Texas, claim to have seen a UFO, described as a mile-wide, silent object with bright lights, flying low and fast. And now it's actual front-page news. So what was it?
"It was very intense, bright lights," said local newspaper reporter Angela Joyner.
"The lights were like going like this," said Constable Leroy Gateman making hand gestures to describe what he saw when he spotted the UFO.
Rick Sorrells says he saw it while he was hunting deer in the woods.
"You look at the trees, and it was right here," Sorrells told ABC News correspondent Mike Von Fremd as he showed him the location in the woods where he spotted the UFO.
Steve Allen, a 50-year-old pilot, was at a campfire with friends and says the object was a mile long and half a mile wide. "I don't know if it was a biblical experience or somebody from a different universe or whatever but it was definitely not from around these parts," Allen said.
Allen drew a sketch of the object, which he said traveled at amazing speed without making a sound. While drawing, Allen told Von Fremd that he saw "an arch shape converted in a vertical shape, and then it split and made two of them, and then these turned into just fire and it was gone."
A spokesman for the 301st Fighter Wing in Fort Worth says no aircraft from his base was in the area, and says the objects may have been an illusion caused by two commercial airplanes. But those who saw the lights don't buy that explanation.
"It's an unidentified flying object," insisted a former Air Force technician.
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"It was so fast I couldn't track it with my binoculars," said Gateman.
Constable Leroy Gateman describes what he saw in the sky.
Some in Stephenville are a bit embarrassed about all the attention. "It's crazy," said one teenage girl in town.
"A lot of folks aren't used to this kind of thing. They are not UFO nuts or anything like that around here," said City Councilman Mark Murphy.
Like it or not, all eyes are now trained on the sky over Stephenville to see whether any mysterious flying objects make a return.
Cue the Twilight Zone theme ... Dozens of people say they saw a UFO hovering over their rural community near Stephenville, Texas. The Stephenville Empire-Tribune says at least 40 people have reported sightings of the object, which reportedly appeared in the sky just after 6 p.m. on Jan. 8.
Lee Roy Gaitan, a local police officer, tells the newspaper: I was outside with my eight-year-old son, Ryan, when I saw lights. It was like nothing I've ever seen before. It was dark already. At first it was two red burning glows that went away and then came back on. I went inside to tell my wife. When I came back out I saw something like lights you'd see in a bar. My little boy and I counted and we came up with nine flashes and they were real spread out. But I couldn't see them attached to anything, just the lights. So I went to my pickup and got my binoculars to see if I could see a plane or something. Even with the binoculars there was no outline. It started moving towards Stephenville and moving so fast I had trouble following it with my binoculars. It covered a big area. It sounds crazy but we really saw what we saw.
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The paper has more eyewitness accounts, including this one from pilot Steve Allen: The ship wasn't really visible and was totally silent, but the lights spanned about a mile long and a half mile wide. The lights went from corner to corner. It was directly above Highway 67 traveling towards Stephenville at a high rate of speed - about 3,000 mph is what I would estimate.
Chuck Mueller, a helicopter pilot who served in Iraq, says he saw unusual lights on the horizon a few days after the UFO sightings were reported near Stephenville.
Mueller tells KXAS-TV that he was flying a medical helicopter around dusk when "we saw the lights come on, one little orange light, and then another one and another one in sequence across the sky." He was shocked at first, but then concluded that the lights, which appeared to be more than 30 miles northeast of the original sightings, were coming from flares that were dropped over the Brownwood Military Operations Area.
There's just one problem with that theory. The NBC station says the military didn't have any planes in the air at the time of the original sightings.
A spokesman for the 301st Fighter Wing at the Joint Reserve Base Naval Air Station tells the Associated Press that he's convinced there's a logical explanation for the lights. "I'm 90 percent sure this was an airliner," Maj. Karl Lewis tells the wire service. "With the sun's angle, it can play tricks on you."
The sightings are big news in rural Texas. The top item on the Stephenville Empire-Tribune's website tells readers where to report a UFO sighting and, below that, the paper notes that a local businessman is offering a $5,000 reward for "video that would confirm a UFO sighting in Selden on Jan. 8."
They're also big news around the world. "The reported sightings have become a catalyst on blogs and in chat rooms, triggering scientific and philosophical debates, religious inquiries, conspiracy charges and bad Texas jokes," the Star-Telegram reports.
The Mutual UFO Network is holding a meeting this weekend for people who saw the object. The non-profit group says its investigators will begin taking statements at 1 p.m. on Saturday.
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The Star-Telegram says this isn't the first time people in that part of the state have reported seeing strange things in the sky. Back in 1897, a Stephenville man told The Dallas Morning News that a 60-foot-long "aerial monster" landed on his farm.
Faster than a speeding bullet — and bigger than a Wal-Mart.
That's how residents near the west Texas town of Stephenville described an object they spotted in the sky one night last week.
Dozens of the town's residents — including a pilot and a police officer — said a UFO hovered over the farming community for about five minutes last Tuesday before streaking away into the night sky.
Pilot Steve Allen saw the object when he was out clearing brush off a hilltop near the town of Silden. Allen described the unidentified object as being an enormous aircraft with flashing strobe lights — and it was totally silent.
He said the UFO sped away at more than 3,000 mph, followed by two fighter jets that were hopelessly outmaneuvered. Allen said it took the aircraft just a few seconds to cross a section of sky that it takes him 20 minutes to fly in his Cessna.
The veteran pilot said the UFO, an estimated half-mile wide and a mile long, was "bigger than a Wal-Mart."
Military Dismisses Sighting
The Stephenville Empire-Tribune, which has written about the mysterious object, said about 40 people saw the thing — though some were too sheepish to admit the sighting until others came forward.
Police officer Leroy Gatin said he was walking to his car when he saw a red glow that reminded him of pictures he'd seen of an erupting volcano.
He said the object was suspended 3,000 feet in the air. Gatin said he was so awestruck that he called his son to come and see — but he didn't talk much about it until he saw a story about a UFO in the local paper.
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Military officials, however, were skeptical. They said the residents are letting their imaginations run wild and passed it off as an optical illusion. They said it was likely nothing more than a reflection of sunlight on two airliners.
Officials at a nearby air force base also said their fighter pilots didn't chase down anything that night.
The incident was eerily similar to a UFO sighting a little more than a year ago at Chicago's O'Hare International Airport.
As many as 12 United Airlines employees spotted the object and filed reports with United.
Combining a megapowerful magnet, multiple detectors, and carefully tweaked contrast, a new MRI technique developed at the National Institutes of Health (NIH) provides an unprecedented look at the fine structure of the brain. Using an MRI machine equipped with a magnet more than twice as powerful as one in an ordinary device, the researchers created a way to measure the magnetic field changes caused by tissue properties to optimize contrast in the image. They were also able to compensate for the magnetic field fluctuations created by the patients’ breathing. The technique revealed never-before-seen patterns in the white matter and gray matter of the human brain.
Picking up on such differences may help researchers look more deeply into the brain’s subdivisions, allowing them to map it in greater detail. It may also bring about advances in diagnosing diseases like Alz–heimer’s and multiple sclerosis, both of which involve abnormal iron accumulation in the brain. For patients, the new technique may mean that “you could more accurately—and maybe earlier—diagnose a disease,” says NIH physicist Jeff Duyn.
Only eight MRI machines this powerful exist in the United States, and all are housed in research, rather than clinical, settings. Each costs around $5 million, and that’s before the expense of setup—which includes installing 380 tons of shielding material to prevent every metal object in the building from being sucked into the magnet.
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Chinese researchers announced (pdf) in March that they had created glass that can be bent into right angles without shattering. But this isn’t glass as we know it: The new glass is opaque, twice as strong as window glass, and made of metal.
As solids, metals have an orderly atomic structure; in liquid metals, the arrangement becomes random, as in glass. To create metallic glass, scientists supercool liquid metals, effectively “freezing” the random array in place. These bulk metallic glasses, or BMG, are two to three times stronger than the crystalline form of the metals.
Superstrong BMG has already been used in the manufacture of high-tech golf clubs and tennis rackets; in 2001, the collector on NASA’s Genesis spacecraft, which caught particles from the solar wind, was made of BMG.
But since the 1980s, when scientists began making BMG, the materials have exhibited a fatal flaw. Paradoxically, the stronger they are, the more vulnerable they are to cracks, says Wei Hua Wang, a physicist who helped develop the new glass at the Chinese Academy of Sciences. A tiny fracture in the original type of BMG spreads quickly and becomes catastrophic.
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To create a glass that is both strong and flexible, Wang and his colleagues altered an existing BMG recipe, combining zirconium, copper, nickel, and aluminum. Realizing that small changes in the metal mixture would lead to large variations in brittleness, they sought a combination that would keep cracks from spreading. “The plasticity of the glass is very sensitive to the composition,” Wang explains.
After two years, the scientists produced bendable BMG. It contains hard areas of high density surrounded by soft regions of low density. The result: When a crack begins in one place, it dissipates quickly in the surrounding regions, leaving the whole flexible.
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Believe it or not, there are some folks who make a living as professional guinea pigs in tests of experimental drugs. Some question whether testing that relies on frequent lab fliers takes advantage of poor people or compromises the quality of the data.
In a recent issue of the New Yorker, bioethics professor Carl Elliot, from the University of Minnesota, details how early drug safety testing has become more of a business transaction than a scientific endeavor in an article called “Guinea-Pigging.” He’ll also be exploring the topic as part of a book he’s writing on corruption, money and medicine that he expects to be called “White Coat, Black Hat” and to be published next year. We asked Elliot, who is on sabbatical in New Zealand, a few questions via e-mail. Here are the highlights of the long-distance conversation:
How does professional guinea-pigging affect the data on experimental drugs?
What I heard about most often was subjects stretching the truth about their medical histories in order to get into high-paying studies. That seems to be fairly common. I don’t know what kind of impact it has on the results, but it shouldn’t be terribly shocking. We have a safety testing system where subjects don’t have any stake in the results of the study, where they don’t really trust the research sponsors, and where they don’t believe they are going to get access to the drugs that are developed by the studies. If poor people are being asked to test drugs for the benefit of rich people, then we shouldn’t be surprised if the poor people are not always perfectly compliant.
Should we change the system to discourage professional guinea-pigging?
Well, one thing that worries me is the damage that all these studies could be doing to the long-term health of the guinea pigs. They are mostly uninsured, so they are in no position to get regular medical care, and nobody else has any financial interest in monitoring their health.
Payment itself is a real dilemma. New drugs need to be tested for safety, and I can’t imagine that many people will volunteer to test the safety of new drugs for free anymore, especially if it means checking into a testing site for three weeks to undergo invasive medical procedures. But it feels unfair to put the burden on poor people who are driven to volunteer at these testing sites because they can’t get any other kind of work. If we are going to have a payment-based system, we need to make sure that poor subjects are not being exploited.
What changes are needed for safety’s sake?
Apart from watchdog groups like Circare, which operate on a shoestring budget, and investigative reporters, there really are very few people outside the research enterprise watching these studies. Formal oversight has been outsourced to for-profit IRBs [institutional review boards], which are paid by the companies doing the research, and which mainly look at studies on paper. The complaints I often heard about from guinea pigs were conditions on the ground that IRBs have never really thought much about. I don’t think it ever occurred to an IRB to ask SFBC [SFBC International, a company that owned the largest drug-testing site in North America] whether they were testing drugs on undocumented immigrants in a dilapidated motel. Some testing sites have procedures that are not really dangerous, but which are uncomfortable or degrading, like requiring subjects to have a rectal exam whether or not it is relevant to the study. And of course, somebody needs to make sure that researchers who are crooked or incompetent are not allowed to keep doing research. http://louis-j-sheehan.biz/page1.aspx
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What can or should be done for participants who are injured or suffer other side effects during a trial?
The very least that can be done is to guarantee that they will get medical care without being stuck with the bill. As things stand now, guinea pigs can’t even count on that. That’s not just a problem with industry studies. Even subjects in federally sponsored trials in universities don’t get that guarantee. Robert Steinbrook published a piece in the New England Journal of Medicine a couple of years ago showing that only 16% of academic health centers in the U.S. provided free care to injured subjects, and none of them compensated subjects for pain and suffering.
Where do you see this process of human subject testing headed?
It’s heading overseas to the developing world. It’s less expensive and the oversight is less rigorous. I think the problems will be the same as here, only more so.
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The sequel is out there.
The conspiracy theories will not be.
Ten years after the first film and six years after the show went off the air, The X-Files returns to theaters with Fox Mulder, Dana Scully — and a lot riding on the bet that fans want more of the FBI's paranormal-investigating agents.
The film, which remains without a formal title, will dump the long-running "mythology" plotline — that aliens live among us and are part of a colonizing effort — that made it one of the most popular television shows in the late 1990s but ultimately drove away some viewers who found it too complex and ambiguous.
"We spent a lot of time on (the mythology) and wrapped up a lot of threads" when the show went off the air in 2002, says Chris Carter, creator of the series and director of the new movie. "We want a stand-alone movie, not a mythology conspiracy one."
That will come as welcome news to fans of the show's stand-alone episodes, which included cults, ghosts, psychics and ancient curses.
Carter refuses to divulge any plot points of the movie, but says he wanted to make the film immediately after the show ended. A contractual dispute with 20th Century Fox kept it on the shelf until the case was settled out of court.
He says the delay may turn out to be a blessing.
"There's a whole audience I want to introduce X-Files to," Carter says. "There were kids who couldn't watch it on TV because it was too scary. Now they're in college. I wanted a movie that everyone could go to."
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Whether they will could be a test of the show's legacy, says Blair Butler of the G4TV network, which caters to video-game enthusiasts and science-fiction fans.
"At its strongest, it had really creepy stand-alone episodes," she says. "They turned it into a great franchise. But a lot of years have passed. We'll see if it's fallen off the radar."
She says the film could benefit from an ironic twist: the Writers Guild strike.
"I think it could be a sort comfort food for the people who loved how original the show was and aren't seeing original TV now," she says.
But Carter believes they'll be drawn by something else: the show's stars, David Duchovny and Gillian Anderson.
"For me, The X-Files has always been a romance," he says. "They had an intellectual romance that's very rare and restrained compared to so many relationships on TV. I think that's what appealed most to the fans. And they're back."
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People have been trying to figure out why we sleep for almost as long as we have been conscious of being awake, tossing and turning in the dark.
After a few restless nights, most of us can't even think straight. We are less able to make sense of problems, make competent moral judgments or retain what we learn, even though studies show our brain cells fire more frenetically to overcome the lack of sleep. Lose too much sleep and we become reckless, emotionally fragile, and more vulnerable to infections and to diabetes, heart disease and obesity, recent research suggests.
We spend a third of our lives asleep, yet no one really knows why. We do know that people simply don't perform as well when they don't sleep enough.
How sleepy are you?
The Epworth Sleepiness Scale can help you rate how likely you are to doze off or fall asleep.
The American Academy of Sleep Medicine and the National Sleep Foundation offer general information about sleep and sleep disorders. The National Institute of Neurological Disorders and Stroke also offers a detailed rundown on the basics of sleep.
New scientific findings about the biology of sleep are highlighted at Sleep Research Online
Bedside Reading
The Society for Neuroscience offers these Brain Briefings on sleep and learning, insomnia and sleep deficits.
For bedside reading about sleep, Stanford University researcher William Dement, founder of the world's first sleep disorder clinic, and science writer Christopher Vaughan outline cures for "a sleep-sick society" in The Promise of Sleep: A Pioneer in Sleep Medicine http://louis-j-sheehan.net
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Yet scientists probing the purpose of sleep are still largely in the dark. "Why we sleep at all is a strange bastion of the unknown," said sleep psychologist Matthew Walker at the University of California in Berkeley.
One vital function of sleep, researchers argue, may be to help our brains sort, store and consolidate new memories, etching experiences more indelibly into the brain's biochemical archives.
Even a 90-minute nap can significantly improve our ability to master new motor skills and strengthen our memories of what we learn, researchers at the University of Haifa in Israel reported last month in Nature Neuroscience. "Napping is as effective as a night's sleep," said psychologist Sara Mednick at the University of California in San Diego.
Moreover, slumber seems to boost our ability to make sense of new knowledge by allowing the brain to detect connections between things we learn.
In research published last April in the Proceedings of the National Academy of Sciences, Dr. Walker and his collaborators at the Harvard Medical School tested 56 college students and found that their ability to discern the big picture in disparate pieces of information improved measurably after the brain could, during a night's sleep, mull things over.
It is these patterns of meaning -- the distilled essence of knowledge -- that we remember so well. "Sleep helps stabilize memory," said neurologist Jeffrey Ellenbogen, director of the sleep medicine program at Massachusetts General Hospital.
The erratic biorhythms of sleep and behavior are intertwined everywhere in nature. Socially active fruit flies need more sleep than loner flies, and even zebra fish can get insomnia.
Sleep is controlled partly by our genes. The difference between those of us who naturally wake at dawn and night owls who are wide-eyed at midnight may be partly due to variations in a gene named Period3, which affects our biological clock. Variations in that gene also make some people especially sensitive to sleep deprivation, scientists at the U.K.'s University of Surrey recently reported.
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How much sleep do you need? And how much do you actually get? Tell us about your sleep habits in an online forum12.
For many of us, though, sleeplessness is a self-inflicted epidemic in which lifestyle overrides basic biology. "In this odd, Western 24-hour-MTV-fast-food generation we have created, we all feel the need to achieve more and more. The one thing that takes a hit is sleep," Dr. Walker said. On average, most people sleep 75 minutes less each night than people did a century ago, sleep surveys record.
Yet, rarely have so many millions of drowsy people been trying so hard to secure some shut-eye, spending billions on sleep aids. By one estimate, pharmacists filled 49 million prescriptions for sleep drugs last year. Even so, we think we sleep more than we actually do, according to Arizona State University scientists. They recorded how long 2,100 volunteers actually slept each night and compared that with how long the people reported they had slept. Most people overestimated their sleep by about 18 minutes, the scientists found.
Psychologists Jeffrey Ellenbogen at Harvard's Mass General Hospital and Matthew Walker at UC/Berkeley found that sleep boosts our ability to make sense of new knowledge by allowing the brain to detect connections and patterns between things we learn. They reported their findings recently in The Proceedings of the National Acemdy of Sciences.
The consequences of too little sleep can be dire. Almost half of all heavy-truck accidents can be traced to driver fatigue, while decisions leading to the Challenger space-shuttle disaster, the Chernobyl nuclear-reactor meltdown and the Exxon Valdez oil spill can be partly linked to people drained of rest by round-the-clock work schedules. Weary doctors make more serious medical errors, while sleepy airport baggage screeners make more security mistakes, researchers reported at the Associated Professional Sleep Societies.
All told, the frayed tempers, short attention spans and fuzzy thinking caused by sleep deprivation may cost $15 billion a year in reduced productivity, the National Commission on Sleep Disorders Research estimated.
The expectation of a nap, however, is by itself enough to measurably lower our blood pressure, researchers at the Liverpool John Moores University in England reported in October in the Journal of Applied Physiology.
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Indeed, regular nappers -- working men who took a siesta for 30 minutes or more at least three times a week -- had a 64% lower risk of heart-related death, researchers at the University of Athens reported last February in the Archives of Internal Medicine.
"All of the things we are proving about sleep and the brain are things that your mother already knew decades ago," Dr. Walker said. "We are putting the science and the hard facts behind it."
Scientists have taken a key step toward understanding the cause of prostate cancer, finding that a combination of five gene variants sharply raises the risk of the disease. Added to family history, they accounted for nearly half of all cases in a study of Swedish men.
The discovery is remarkable not just for the big portion of cases it might explain, but also because this relatively new approach -- looking at combos rather than single genes -- may help solve the mystery of many complex diseases.
It also might lead to a blood test to predict who is likely to develop prostate cancer. These men could be closely monitored and perhaps offered hormone-blocking drugs like finasteride to try to prevent the disease.
The Swedish results must be verified in other countries and races, where the gene variants, or markers, may not be as common. Researchers already have plans to look for them in U.S. men. Unfortunately, the markers do not help doctors tell which cancers need treatment and which do not -- they turned out to have nothing to do with the aggressiveness of a tumor, only whether a man is likely to develop one.
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The study was led by doctors at Wake Forest University in Winston-Salem, N.C., and involved Johns Hopkins University in Baltimore and the Karolinska Institute in Stockholm. Results were published online by the New England Journal of Medicine.
It involved 2,893 men with prostate cancer and 1,781 similar men who did not have the disease. Sweden was chosen because the population is so ethnically similar and well suited to gene studies.
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