大家好，胖胖翔来发科技文咯！标题用白色标记的，读完文章后用鼠标拖动一下就看到了，在正文上面~
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[Time 1]Article 1 ( Check the title later )
The True Shape of Snowflakes
The classic image of a snowflake is a fluke. That flat, six-sided crystal with delicate filigree patterns of sharp branches occurs in only about one in every 1000 flakes. And a snowflake seen in 3D is another beast entirely. Researchers have developed a camera system that shoots untouched flakes "in the wild" as they fall from the sky. By grabbing a series of images of the tumbling crystals—its exposure time is one-40,000th of a second, compared with about one-200th in normal photography—the camera is revealing the true shape diversity of snowflakes. For example, long before they reach the ground, many flakes are attacked by millions of freezing water droplets and end up as rough little ice pellets known as graupel. Flakes that avoid that process often end up sticking to other flakes, forming big, fluffy aggregates in midflight. And even those flakes that trace a lonely path through the air are usually not flat but bushy. (Some of this variety is showcased in the picture above.) Besides providing beautiful real-time 3D snowflake photographs from a ski resort in Utah, the goal is to improve weather modeling. More accurate data on how fast snowflakes fall and how their shapes interacts with radar will improve predictions of when and where storms will dump snow and how much.
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Article 2
Are Home Runs All in the Cheekbones?
We rely on people's faces for information about their mood, personality, character, and … baseball prowess? Very likely, according to a new study. In men, a greater facial width-to-height ratio (a wider or broader face) is thought to be influenced by levels of testosterone at puberty. A high width-to-height ratio has been linked to the strength of hand grip, the drive to achieve, and competitiveness. Following these implications to a logical conclusion, a team of researchers wondered if men with broader faces would prove to be better baseball players. Sure enough, a study of 81 Japanese professional sluggers showed that those with wider faces had a higher rate of home runs across two consecutive seasons, according to a finding appearing online today in Biology Letters. (The hitters didn’t top the record of the legendary Sadaharu Oh of the Yomiuri Giants, pictured, who led all Japanese players in home runs 15 times.) No such link was found with other stats such as batting average, and only a slight association with runs batted in turned up in the second season. Previous studies have connected facial width-to-height ratio with sports performance, but only in Caucasians. The new finding in an Asian group suggests that the effect of facial width relative to height—even other characteristics—may cross cultural and ethnic boundaries.
[字数：218] [Time 3]
Article 3
Supernova left its mark in ancient bacteria
Sediment in a deep-sea core may hold radioactive iron spewed by a distant supernova 2.2 million years ago and preserved in the fossilized remains of iron-loving bacteria. If confirmed, the iron traces would be the first biological signature of a specific exploding star. Shawn Bishop, a physicist at the Technical University of Munich in Germany, reported preliminary findings on 14 April at a meeting of the American Physical Society in Denver, Colorado.
In 2004, scientists reported finding the isotope iron-60, which does not form on Earth, in a piece of sea floor from the Pacific Ocean1. They calculated how long ago this radioactive isotope had arrived by using the rate at which it decays over time. The culprit, they concluded, was a supernova in the cosmic neighbourhood.
Iron sink
Bishop wondered if he could find signs of that explosion in the fossil record on Earth2. Some natural candidates are certain species of bacteria that gather iron from their environment to create 100-nanometre-wide magnetic crystals, which the microbes use to orient themselves within Earth’s magnetic field so that they can navigate to their preferred conditions. These 'magnetotactic' bacteria live in sea-floor sediments.
So Bishop and his colleagues acquired parts of a sediment core from the eastern equatorial Pacific Ocean, dating to between about 1.7 million and 3.3 million years ago. They took sediment samples from strata corresponding to periods roughly 100,000 years apart, and treated them with a chemical technique that extracts iron-60 but not iron from nonbiological sources, such as soil washing off the continents. The scientists then ran the samples through a mass spectrometer to see if any iron-60 was present.And it was. “It looks like there’s something there,” Bishop told reporters at the Denver meeting. The levels of iron-60 are minuscule, but the only place they seem to appear is in layers dated to around 2.2 million years ago. This apparent signal of iron-60, Bishop said, could be the remains of magnetite (Fe3O4) chains formed by bacteria on the sea floor as radioactive supernova debris showered on them from the atmosphere, after crossing inter-stellar space at nearly the speed of light.
No one is sure what particular star might have exploded at this time, although one paper points to suspects in the Scorpius–Centaurus stellar association, at a distance of about 130 parsecs (424 light years) from the Sun3.
“I’m really excited about this,” says Brian Thomas, an astrophysicist at Washburn University in Topeka, Kansas, who was not involved in the work. “The nice thing is that it’s directly tied to a specific event.”
“For me, philosophically, the charm is that this is sitting in the fossil record of our planet,” Bishop says. He and his team are now working on a second core, also from the Pacific, to see if it too holds the iron-60 signal.
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[Time 4]
Article 4
Giant Hawaiian telescope gets go-ahead for construction
Hawaiian officials have granted a permit for the planned Thirty Meter Telescope (TMT) to proceed atop the sacred mountain of Mauna Kea, project officials announced on 13 April.
The move clears the way for construction to start, as early as April 2014, atop the 4,200-metre-high summit. Thirteen telescopes already dot the mountain, but the TMT would be the largest of them by far. The biggest optical telescopes now atop Mauna Kea are the twin 10-metre Keck telescopes. Development on the mountain is a sensitive subject in Hawaii. In 2011, the state’s board of land and natural resources granted a conditional permit to construct the TMT. Opponents pursued a contested case hearing under a board officer. The new decision confirms the original permit granting and moves the TMT forward for good. Ed Stone, a physicist at the California Institute of Technology in Pasadena and vice-chairman of the TMT board, says that the telescope offers opportunities for discovery that astronomers haven’t yet even dreamed of. Scientific operations could begin in 2021.
Other Mauna Kea projects haven’t always fared as well. In 2006, amid controversy over development, NASA pulled funding for a set of smaller ‘outrigger’ telescopes to accompany the twin Keck telescopes. On the neighbouring island of Maui, solar astronomers last November received their own construction permit to move ahead with the 4-metre Advanced Technology Solar Telescope, the biggest such facility ever planned, atop the mountain of Haleakala — but only after agreeing to concessions such as hiring a cultural specialist and having construction workers receive mandatory ‘sense-of-place’ training.
TMT officials picked Mauna Kea over Chile in 2009 for the site for its behemoth, 492-segment mirror. Like other mountain summits in Hawaii, Mauna Kea is held in trust by the state for the public good. The University of Hawaii leases the observing site, and the TMT would sublease from the university.
In March, the TMT officially partnered with the US National Science Foundation (NSF). Its rival, the 25-metre Giant Magellan Telescope planned for Chile, had opted out of competing for the NSF partnership. Last fall, the GMT announced that it had finished the first of the seven 8.4-metre mirrors meant to make up its heart. In a third giant-telescope plan, the European Southern Observatory is trying to corral funds to move ahead with its own telescope on the same scale, the 39-metre Extremely Large Telescope, also planned for Chile. The United Kingdom confirmed last month that it would contribute, bringing the total to 11 member states who are on board.
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Article 5
This date in science: Leonhard Euler’s 306th birthday
April 15, 1707. Leonhard Euler’s 306th birthday is today. He was born on April 15, 1707. Today Google, the search engine giant, is celebrating with an animated Google doodle. If you’re looking on April 15, 2013, you’ll see the animated version of Leonhard Euler’s google doodle here. Leonhard Euler was born in Basel, Switzerland. He was a physicist and mathematician whose contribution and discoveries continue to be significant in the fields of infinitesimal calculus and graph theory. In fact, his most famous theorem (V – E + F = 2) might have shown up in your algebra or geometry class. The formula also appears on the April 15, 2013 Goggle doodle. This work by Euler is now known as the Euler characteristic. Mathematicians compute this Euler Characteristic to create a mathematical description of the shape of a surface, no matter which way the surface is bent. Read more about the Euler Characteristic here. Euler was considered a prodigy. He was enrolled at the University of Basel at the age of 13. In 1723, at the age of 16, he received his Master of Philosophy.
Thank you EarthSky Facebook and G+ friend Kausor Khan for alerting us to today’s Google doodle! Bottom line: The Google doodle for April 16, 2013 honors Leonhard Euler, whose 306th birthday is today.
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Article 6Sniffing out Dermatemys
Border collies are well known for their ability to herd sheep, but Milena Mendez has another job in mind for Fenix, her 10-month-old companion. Mendez, who graduated from University of Valle in Guatemala in March with a degree in biology, is studying the rare turtle Dermatemys mawii, known as the Central American river turtle and colloquially as the hickatee. But to study them she has to find them, and that's where she hopes Fenix will help.
Finding the turtles isn't easy. Her fieldwork takes place in the remote Sarstún River on the border between Guatemala and Belize. Just getting there from her home in Guatemala City requires multiple buses and boats. And the big freshwater turtles don't bask in the open air like other freshwater turtles; they spend their whole lives underwater. Still, she has managed to make progress without canine assistance, surveying habitats, capturing and measuring, and analyzing feces to determine the turtle’s diet. She also collects tissue samples in anticipation of genetic analysis.
One day, Mendez got a tip from one of her field assistants, a villager named Cush. Today, Cush assists Mendez’s conservation work, but like many villagers in the area, he makes his living from the river and was once a renowned hickatee hunter. One of his secrets: He trained his dog to sniff out turtles and even their well-hidden nests.
A dog enthusiast, Mendez had recently bought a puppy from one of the few border collie breeders in Guatemala. She planned to train the dog for agility contests—until she decided to try engaging Fenix in more meaningful pursuits.
Mendez's work with the hickatee started when she was an undergraduate, after an internship at Zoo Atlanta led to an interest in turtles and an invitation the following year to attend a Turtle Survival Alliance meeting. The alliance’s director learned that she was from Guatemala and approached her about studying the Sarstún River's Dermatemys. Mendez agreed readily, in part because she'd seen a hickatee: It is a striking creature. Its head may be yellow, olive green, or orange, and specimens can weigh up to 45 pounds. It has a primitive look—and indeed, the fossil record shows that 19 genera of Dermatemydidae existed at one time or another, but only the hickatee remains from a lineage that can be traced to the Jurassic period in Europe and the Cretaceous in North America and East Asia. "They're the coolest turtles we have [in Guatemala]," Mendez says.
The hickatee's flesh has been prized since ancient times. Fishermen often net them inadvertently, and villagers raise them to be consumed at celebrations. But when what was once a ritual became a large commercial trade in the 1980s—hickatee flesh can command up to $45 a pound—the turtles nearly vanished from Mexico, where they were once common. Populations in Guatemala and Belize are in better shape but still endangered.
A new species?
Scarcity makes the Sarstún River population critical, but there is another reason to study the hickatee: Two genetically separate hickatee populations in the Sarstún River may be separate species.
Gracia Patricia González-Porter, now a postdoctoral fellow in the laboratory of zoology at the Autonomous University of Querétaro in Santiago de Querétaro, Mexico, was the lead author of a phylogeographic analysis of the hickatee, which included 238 individuals from 15 regions throughout its range. The group identified 16 haplotypes. One of them, 1D, differed by about 2% from other haplogroups, a spread that in other turtles often indicates a separate species. Turtles with the 1D haplotype were found in only Guatemala, in the Sarstún and Salinas rivers. Actually, the Sarstún River animals that they studied came from a zoo in Philadelphia, where they lived after being captured by zoo conservationists. González-Porter is hoping to work with Mendez to collect more samples and conduct genetic analyses to determine if 1D haplotype animals are breeding with other turtles in Sarstún populations. If the distinct populations aren't interbreeding, González-Porter is ready to conclude that there are two species, not one. "If Dermatemys is already critically endangered, this lineage [1D] must be much more endangered than the rest of the species. I think the work that Milena is doing is very important because of this," she says.
Fenix, rising
Mendez is preparing Fenix to assist. Using two species of pet slider turtles (Trachemys venusta and Trachemys scripta elegans), she taught the dog to sniff and touch the turtle's shell with her nose and then to retrieve them. She hid turtles around the house and encouraged Fenix to find them. Fenix still needs to learn to be gentle; she has a tendency to get excited when she finds a turtle and can be a bit rough.
There are dangers for Fenix, too. The Sarstún River is home to poisonous vipers and toads, which the dog must learn to avoid. A friend of Mendez, who works at a zoo in Guatemala City, lent Mendez some vipers, which she keeps in a box and places in various spots. She lets the dog find them and gives a correction when she starts to get too close. "I don't like seeing her scared, looking at me like 'Oh, no, what's happening?' " Mendez says. "But I'd rather see her scared for a couple of weeks than bitten by a venomous snake."
Ecological thinking
González-Porter is developing an international plan for conserving Dermatemys in Mexico, Belize, and Guatemala. Mendez is working with the Sarstún River population and applying for funding from the Turtle Survival Alliance and Fundaeco, a nonprofit foundation for ecological development and conservation that is heavily involved in the Sarstún region. She hopes to put together a conservation plan to protect this Dermatemys population. But the experience of working with Cush and other villagers has changed her perspective and her plans. She had intended to do increasingly detailed surveys, "but now I think I need to focus on the villagers and the community, because they are the key for success of a conservation strategy," she says.
She hopes to recruit villagers to conduct some additional surveys, but she intends to go much further. Public education in the village—El Aguacate—now ends after 10th grade, and the schools are sweltering. "The kids are desperate to get out because it's so hot, and it's really hard to pay attention in an environment like that. They have little chance of [bettering themselves] or getting a good job," Mendez says.
Mendez is developing connections with teachers, conservationists, and others. She plans to transform the schools in the area, starting with improved facilities. After that, she hopes to develop curricula that apply more directly to the children's lives. "[The teachers] try to give them a lot of information that maybe the city people [need], but the country people have other interests. I feel like they don't see the point of study, because what they teach them is not going to help them," she says. She envisions a teaching environment where scientific principles are incorporated and where children can apply the scientific method to learn about the river that is so important to their livelihood.
"I really think environmental education is good, and it can solve a lot of environmental problems, but you need to do it well. You can't just go and tell them, 'Don't eat Dermatemys or don't kill Dermatemys,' because you're just imposing concepts that they might not even care about," Mendez says. "I think using the scientific method you can do a lot of activities and teach them to value their natural resources better, and then eventually I think [that], by themselves, they're going to preserve the ecosystems and natural resources because they already know they're important but they don't know why. I think if they figure out why by themselves, it's better than just imposing."
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发表于 2013-4-16 20:44:46
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