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Years after straightening teeth, the thin metal wires from orthodontic braces can end up twisting intestines, according to a report published Monday in BMJ Case Reports.
Australian doctors found a seven-centimeter bit of dental brace wire in the bowels of an otherwise healthy 30-year-old woman. She told doctors she had her braces removed 10 years earlier and didn’t recall swallowing or missing any bits of wire.
The case seemed to flabbergast her doctors. Most of the time, if an inert foreign object reaches a person’s intestines, it can pass the rest of the way without a problem. But things that do end up getting stuck tend to do so at the sphincter muscle valve that separates the small and large intestines. In the case of the woman in Australia, the wire was caught tearing up and twisting the middle of her small intestine.
In a lot of ways, stars are our model for creating nuclear fusion here on Earth, with fusion power often promoted as "harnessing the power of the Sun." For all that, however, we have some surprising gaps in our understanding of what's going on inside stars. That's partly because we must infer what's going on there based on the elements and particles that reach the solar surface, and partly because finding ways to test our theoretical models of fusion reactions is so difficult.
So there's a certain appealing symmetry about a paper that was released by Nature Physics today. In it, researchers describe using the National Ignition Facility, built to study fusion using a giant laser, as a model for the interior of heavy stars. The results show that, despite their limitations, our earlier efforts to understand stellar fusion were on the right track.Cross checking the cross-section
On a simple level, most stars fuse hydrogen to form helium. But things are obviously more complex than that. Most of the hydrogen in our Sun is the lightest form, with just a single proton as its nucleus. The helium produced in stars has two protons and two neutrons. Obviously, making helium from only protons requires a series of nuclear reactions, each with distinct probabilities of occurring that depend in part on the conditions inside the star. Complicating matters further, there are some other possible reactions that don't lead directly to helium but can still occur inside a star, producing things like heavier isotopes of hydrogen.
More than a millennium ago, people in the Viking Age city of Haithabu dined on a dish of freeze-dried cod and tossed the bones aside. It was a relatively unremarkable meal, except for one thing. The DNA in those bones was preserved into the present day, and scientists in Norway have just sequenced it. What they found has confirmed the truth of stories from the Icelandic sagas about Vikings sailing exceptionally long routes to trade with other groups.
Today, the coastal city of Haithabu is an archaeological site in Germany on the Baltic Sea. But the people who munched on that dried cod roughly 1,000 years ago were living under Danish rule in a cosmopolitan port city. Haithabu was a key stop on a lively sea trade route that brought tasty treats and trinkets like walrus tusks from distant lands. Though there is ample evidence of this kind of trade 800 years ago, University of Oslo environmental biologist Bastiaan Star and his colleagues have pushed that date back at least 200 years, and possibly 400, just by sequencing cod DNA. This dramatically changes our understanding of long-distance trade in Northern Europe during the Viking Age.
In Proceedings of the National Academy of Sciences, Star and his team describe how they used DNA analysis to trace the origins of 15 different cod eaten centuries ago in Germany, Norway, and the UK. The group has been studying ancient cod DNA to better understand the way humans have affected the migration routes and populations of this staple fish over time. This new discovery, however, has shed light on international trade. By comparing DNA sequences from ancient cod with modern ones, the researchers found that certain populations of fish have stuck to the same breeding grounds and migration routes for at least 1,200 years. Small mutations in the cod genome reveal which population the individual comes from, and that in turn reveals where they spawned.
Centrafrique : des armes vendues " au vu et au su de tout le monde " sur des marchés, selon des experts onusiens
After an intense football match Saturday in Australia, 16-year-old Sam Kanizay dipped his legs into the chilly waters off Melbourne’s coast, hoping to soothe his sore muscles. Half-an-hour later he stepped out, bleeding profusely from countless tiny bites.
The gory and bizarre scenario is now making international headlines. The images of his feet and ankles (here and here) really are quite disturbing (you’ve been warned). But the incident left medical professionals initially confused and media reports garbled. Some blamed the vicious attack on wee crustaceans called isopods, or “sea lice,” but experts are trying to clear up that error.
In a press statement Monday, local authorities reported that marine scientists had identified the flesh-eaters as lysianassid amphipods, a type of scavenging crustacean sometimes called “sea fleas.” They’re not known for swarming and attacking people. But scientists have long studied their affinity for flesh and ability to sniff it out in warm, cool, deep, and shallow waters around the world. Typically, they descend upon carcasses of marine animals and munch away the meat, tiny-bite by tiny-bite.
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Humans have launched some momentous missions of discovery into the universe. Yuri Gagarin reached orbit. The Apollo astronauts walked across the Moon. The Viking probes landed on Mars. But never before had a spacecraft visited four worlds in a single, grand tour as the two Voyager probes did in the 1970s and 1980s with Jupiter, Saturn, Uranus and Neptune. And the story behind these two spacecraft, along with the people who made them fly, is utterly compelling.
Fortunately, on their 40th anniversary, PBS has produced a 90-minute documentary worthy of these missions. Featuring interviews with many of the principal scientists and imaging experts, The Farthest tells the story of how Voyager 1 and 2 were conceived, where they flew, and what they discovered while detailing all the drama in between. The documentary debuts on August 20.