65243345
submission
sciencehabit writes:
A team of researchers has now taken the street maps of the world's major cities and analyzed them as mathematical networks. It turns out that all cities can be boiled down to just four different types based on the "fingerprint" of their street networks: a grid of medium-sized blocks that are mostly square or regular rectangles, a dominant fraction of small blocks with a diverse array of shapes, mostly medium-sized blocks with diverse shapes, or a mosaic of patches of mostly small squares or rectangles. For example, those who say that American and European cities tend to be "laid out differently" now have mathematical evidence. Boston's famously confusing street map—which produces small and diversely shaped city blocks—is more like a European city’s than that of the typical gridlike U.S. city. And some of the largest cities are revealed to be a hodgepodge of different parts. The five boroughs of New York City are closer matches to different cities around the world than they are to each other. Manhattan has the gridlike street layout of Brazilian cities like Campo Grande and Curitiba, while the Bronx’s streets look like those of Porto, Portugal. Brooklyn is strikingly similar to Detroit, Michigan, at least in layout. And Staten Island? It’s like walking the streets of As-Suwayda, Syria.
65243281
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sciencehabit writes:
Two years ago, scientists showed that dolphins imitate the sounds of whales. Now, it seems, whales have returned the favor. Researchers analyzed the vocal repertoires of 10 captive orcas, three of which lived with bottlenose dolphins and the rest with their own kind. Of the 1551 vocalizations these seven latter orcas made, more than 95% were the typical pulsed calls of killer whales. In contrast, the three orcas that had only dolphins as pals busily whistled and emitted dolphinlike click trains and terminal buzzes, the scientists report in the October issue of The Journal of the Acoustical Society of America. The findings make orcas one of the few species of animals that, like humans, is capable of vocal learning—a talent considered a key underpinning of language.
65207045
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sciencehabit writes:
If you sailed through school with high grades and perfect test scores, you probably did it with traits beyond sheer smarts. A new study of more than 6000 pairs of twins finds that academic achievement is influenced by genes affecting motivation, personality, confidence, and dozens of other traits, in addition to those that shape intelligence. The results may lead to new ways to improve childhood education.
65207029
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sciencehabit writes:
More than a quarter of all Internet traffic belongs to BitTorrent, a file-sharing system that allows users to swap everything from music to movies. Now, for the first time, researchers have revealed a link between a country’s economy and the type of files its residents download from BitTorrent. The findings are shedding new light on online behavior and could help law enforcement track down Internet pirates.
What really stood out is that users from the same country displayed a tendency to download the same types of content. After factoring socioeconomic indicators such as a country’s gross domestic product per capita and Internet access, analysis showed that users from rich countries such as the United States tended to download more music files, whereas users from poorer countries such as Spain favored movie files. the availability of online streaming services such as Netflix may have curbed the tendency for Americans to download movies and TV shows. In contrast, in countries like Spain, where no such services are available, downloading has become the prevalent way to access such content.
65201549
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sciencehabit writes:
The victim peers across the courtroom, points at a man sitting next to a defense lawyer, and confidently says, "That's him!" Such moments have a powerful sway on jurors who decide the fate of thousands of people every day in criminal cases. But how reliable is eyewitness testimony? A new report concludes that the use of eyewitness accounts need tighter control, and among its recommendations is a call for a more scientific approach to how eyewitnesses identify suspects during the classic police lineup.
65115787
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sciencehabit writes:
Oceanographers have a saying: Scientists know more about the surface of Mars than they do about the landscape at the bottom of our oceans. But that may soon change. Using data from satellites that measure variations in Earth’s gravitational field, researchers have found a new and more accurate way to map the sea floor. The improved resolution has already allowed them to identify previously hidden features—including thousands of extinct volcanoes more than 1000 meters tall—as well as piece together some lingering uncertainties in Earth’s ancient history.
65092337
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sciencehabit writes:
Scientists have found a nearly square peg underneath a round hole—on the moon. Several kilometers below Oceanus Procellarum, the largest dark spot on the moon’s near side, scientists have discovered a giant rectangle thought to be the remnants of a geological plumbing system that spilled lava across the moon about 3.5 billion years ago. The features are similar to rift valleys on Earth—regions where the crust is cooling, contracting, and ripping apart. Their existence shows that the moon, early in its history, experienced tectonic and volcanic activity normally associated with much bigger planets.
65072683
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sciencehabit writes:
The tiny swirls created by brine shrimp and other minuscule aquatic creatures could mix the seas’ upper layers as well as winds and waves do, a new study suggests. Such “biomixing” could play an important role in redistributing heat, salt, and nutrients in the upper layers of the ocean. However, some researchers question how effectively biomixing blends the waters of the wave-thrashed sunlit surface with those from the cool, calm depths. The work comes thanks to blue and green lasers, which were used to induce thousands of 5-millimeter-long brine shrimp to “migrate” to and from the bottom of a 1.2-meter-deep tank.
65072655
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sciencehabit writes:
A wind turbine, a roaring crowd at a football game, a jet engine running full throttle: Each of these things produces sound waves that are well below the frequencies humans can hear. But just because you can’t hear the low-frequency components of these sounds doesn’t mean they have no effect on your ears. Listening to just 90 seconds of low-frequency sound can change the way your inner ear works for minutes after the noise ends, a new study shows.
64905117
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sciencehabit writes:
An underwater landslide the size of the Paris may have triggered the worst of the tsunami that struck Japan on 11 March 2011, a new study claims. In the new study, researchers worked back from details of the ocean surface motion recorded by gauges along the Japanese shore on the day of the earthquake. Much as sound waves can help the ear pinpoint the source of a gunshot and whether a small pistol or a large cannon fired it, tsunami waves carry the imprint of the ocean floor disturbance that created them. The team concludes that during the earthquake a slab of sediment 20 km by 40 km and up to 2 km thick slid about 300 meters down the steep slope of Japan Trench, “acting like a piston.”
64896085
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sciencehabit writes:
Researchers are closer to unraveling the mystery of how Timothy Ray Brown, the only human cured of HIV, defeated the virus, according to a new study. Although the work doesn’t provide a definitive answer, it rules out one possible explanation.
64841785
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sciencehabit writes:
On Vieques Island off the coast of Puerto Rico, two ancient South American tribes coexisted for more than 1000 years, from 5 to 1170 C.E. The Saladoids were known for their white and red painted pottery, as well as their openness to learning from other cultures. The Huecoids, in contrast, were mysterious craftsmen who skillfully carved semiprecious stones and kept to themselves. For the past 20 years, archaeologists have debated whether the two tribes belonged to the same culture or distinct cultures with origins in present-day Venezuela and Bolivia, respectively. So researchers resorted to coprolites—fossilized feces excavated from the tribes’ settlements. The ancient dung, contains gut microbes that provide clues to the two populations’ diets. After extracting and analyzing DNA at the core of the coprolites, the researchers found that although both tribes consumed seafood, only the Saladoid samples contained freshwater fish parasites, suggesting that the tribe consumed raw fish regularly. The Huecoids, on the other hand, showed a preference for maize and fungi. The tribes’ distinct diets suggest that they indeed belonged to different cultures, the researchers report.
64836515
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sciencehabit writes:
Academic scientists with federal funding who work with any of 15 dangerous microbes or toxins will soon have to flag specific studies that could potentially be used to cause harm and work with their institutions to reduce risks, according to new U.S. government rules released today. The long-awaited final rule is similar to a February 2013 draft and is “about what we expected,” says Carrie Wolinetz, a deputy director of federal relations at the Association of American Universities (AAU) in Washington, D.C., which represents more than 60 major research universities. Those schools see the rules as replicating other federal security and safety rules, Wolinetz says, but will adjust to them. But some observers have concerns, such as that the rules do not apply to other risky biological agents. In a conference call with reporters today, a White House official said the government is open to a “broader discussion” about whether it should expand the list of 15 regulated agents.
64803945
submission
sciencehabit writes:
Press the backs of your hands against the inside of a door frame for 30 seconds—as if you’re trying to widen the frame—and then let your arms down; you’ll feel something odd. Your arms will float up from your sides, as if lifted by an external force. Scientists call this Kohnstamm phenomenon, but you may know it as the floating arm trick. Now, researchers have studied what happens in a person’s brain and nerve cells when they repress this involuntary movement, holding their arms tightly by their sides instead of letting them float up. Understanding what's going on could help people repress other involuntary movements—including the tremors associated with Parkinson’s disease and the tics associated with Tourette syndrome.
64803905
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sciencehabit writes:
Researchers have found the earliest evidence for limb regeneration in the fossil record. Rocks unearthed in southwestern Germany have captured 300-million-year-old relatives of the salamander that have one or more regrown limbs. The finding shows that the constant ability to regenerate whole limbs is not unique to modern salamanders, contrary to traditional assumptions. The researchers suggest that this process may have a shared genetic basis that evolved early in the amphibian lineage (and was lost or modified in later species with limited or no regenerative ability), and that part of this foundation may even be a primitive characteristic of four-legged animals in general.
