Why sperm, you ask? As described in New Scientist,
Sperm cells are an attractive option because they are harmless to the human body, do not require an external power source, and can swim through viscous liquids.
But sperm don’t inherently go where you want them to go. Thus the scientists used some clever nano-engineering to rein them in.
Scientists put bull sperm cells in a petri dish along with a couple dozen iron-titanium nanotubes. The tubes act like those woven fingertraps—sperm can swim into them but can’t back themselves out. Using magnets, scientists can then steer the swimmers in the direction of their choosing. It’s like a remote-control robot where the sperm start the engines and the researchers provide the navigation.
For the last two decades, the United States has been drawing about a tenth of its electrical power from an unlikely source: the uranium from 20,000 decommissioned Russian nuclear bombs. But today marks the end of this energy exchange era.
The arrangement with a former adversary may seem strange, especially since these are the very bombs that Americans once feared would be used against them. But on a practical level, the program, called Megatons to Megawatts, actually makes a lot of sense.
When the Cold War ended, the Russian and U.S. governments struck a deal: Russia would turn the uranium from its decommissioned warheads into nuclear fuel. The U.S. would buy this fuel and sell it to commercial nuclear power plants back home. The exchange was a way for the former Soviet Union to clean up its military facilities and get paid to do it.
Good news for those searching for life elsewhere in the universe: a study released today suggests that planets orbiting surprisingly close to their stars can remain livable. This extension of the so-called habitable zone, based on computer modeling, is also important for what it implies about our own planet’s future habitability.
Studying habitable zones has always been tricky, because there’s only one habitable planet we know of—our own. Still, astronomers have established the general boundaries for what they call a star’s habitable zone, the donut-shaped region around that star where an Earth-like planet could host liquid water, necessary for life as we know it. At the zone’s outer edge water freezes from the cold, and at the inner edge it evaporates from the heat; conditions are “just right” inside the zone, hence the area’s other common nickname: the Goldilocks zone.
When a women sees an overtly sexual advertisement, studies have found, her gut reaction tends to be negative. There’s a psychological explanation for this, and it’s called sexual economics theory: women want sex to be something rare and valuable.
But this got researchers at the University of Minnesota thinking: What if the product being sold, itself, was rare and valuable? Would a sexy advertisement appeal more to women than a non-sexy one in that case?
Here’s another thing to keep the world’s epidemiologists up at night: The new strain of bird flu known as H7N9 can mutate to be resistant to the only influenza therapy available. And it can do so without losing its ability to transmit between hosts.
H7N9 is a flu strain that resides naturally in wild waterfowl. But it showed up in domestic birds in the poultry markets of eastern China earlier this year. From there, the virus spread to humans, mostly through direct contact with infected poultry. So far, H7N9 infections have been confirmed in more than 140 people in east Asia, 45 of whom have died.
It’s often claimed that our 24-hour news cycle distorts the headlines, making mountains out of molehills and covering big stories ad nauseam. Now there’s scientific evidence that watching such repetitive coverage of a traumatic event can emotionally harm viewers more than the event itself.
Researchers came to this conclusion in a study of the Boston Marathon bombing on April 15. They conducted an Internet survey of more than 4,000 Americans from across the country between two and four weeks after the attack. Researchers asked participants about their emotional stress, whether they were personally affected by the bombing, and their news-watching habits (both on traditional and social media).
The survey included a disproportionate number of Boston residents so that researchers could compare those who had been directly affected by the bombing with those who had only watched it on the news. In total, about 10 percent of survey respondents were either exposed to the event themselves or had a close acquaintance who was.
Big news today from the Martian front. New data from everyone’s favorite car-sized roving robot, Curiosity, has come out, with implications for potential life on the Red Planet.
At a press conference today at the American Geophysical Union’s fall meeting in San Francisco, and in a bundle of six Science papers, scientists announced the extreme likelihood of an ancient lake near Curiosity’s landing site that was habitable for certain microbes, as well as greater details about the geological history of the landing site and the amount of harmful radiation that the rover’s been exposed to.
You may be forgiven for thinking this sounds a bit familiar.
Freshwater is fast becoming a scarce resource as our global population swells. Some say World War III will be fought over access to it. But newfound reserves of freshwater under the sea may represent a vast source that has been previously overlooked.
Researchers announced this week that they’ve probed the extent of freshwater reserves under the sea off the coasts of South Africa, China, North America and Australia. Scientists have known about these pockets for a while but had no idea how many or how large they were. Now researchers estimate they contain about 120,000 cubic miles of water. Each cubic mile is equivalent to 1.1 trillion gallons, enough water to satisfy all of the United States’ present water usage for about 9 days. The lead researcher put it in perspective for Agence France Presse,
“The volume of this water resource is a hundred times greater than the amount we’ve extracted from the Earth’s sub-surface in the past century.”
Dyslexia affects about one in ten people of all ages, inhibiting their ability to read and spell. In our language-driven world, that’s a real problem. Researchers have long debated the brain basis of the condition, and a new study provides a pretty convincing answer.
Language is built of little individual sounds called phonemes. During language development, the brain learns how to identify these sounds and distinguish between them, correcting for variations in tone, accent, etc. Then the brain must learn how to arrange these individual pieces into very specific combinations called “phonetic representations.” This is where the breakdown is thought to occur in the dyslexic brain. As described in Science,
For the past 40 years, researchers have thought that people with dyslexia don’t develop precise “phonetic representations” and thus can’t recognize fine distinctions in language. The distorted representations, like smudged words in a dictionary, might not be evident in everyday speech, but they could make learning to read and spell quite difficult, especially for words that don’t follow obvious spelling or pronunciation rules, such as “bough” and “cough.”
Researchers have successfully sequenced the oldest known human DNA, and it points to unexpected relationships between hominid populations scattered across the length of Eurasia.
The genetic material came from a 400,000-year-old femur of Homo heidelbergensis, an early hominid considered to be the ancestor of both Neanderthals and modern humans. The achievement pushes back the age of the oldest hominid DNA sequencing by 200,000 years.
The site of the fossil’s discovery, Sima de los Huesos (“pit of bones”) in northern Spain, has yielded remains of more than two dozen individuals dated to older than 300,000 years. The skeletons found at Sima de los Huesos exhibit Neanderthal-derived traits, leading researchers to anticipate a strong relation to Homo neanderthalensis.