科学与翻译

Skilled jade craftsmen may have helped to spread the Austronesian languages. 

Prehistoric purveyors of jade spread their trade from a single Taiwanese source throughout a huge area of Southeast Asia, possibly bringing Austronesian languages with them.

From as early as 3000 BC people from Southeast Asia used jade to make tools and ornaments. This later included ear pendants, such as a three-pointed jade ornament called a lingling-o. These ornaments have been found in southeastern Taiwan, and also all the way out to the Philippines, eastern Malaysia, southern Vietnam, central and southern Thailand, and parts of Cambodia.

Hsiao-Chun Hung, at the Australian National University in Canberra, and her colleagues took a close look at lingling-o and other pendants found in archaeological digs across Southeast Asia, to find out where they came from.

Rather than focus on the style and patterning on the ornaments, Hung used an electron probe microscope, which can work out the elemental composition of each sample without causing any damage. This is the first time that the technique has been used to look at jade, says Hung.

Her work shows that 116 of 144 jade ornaments from across the 3,000-kilometre-wide region came from the Fengtian jade deposit in eastern Taiwan. The Fengtian samples included incomplete ornaments and cast-off pieces of jade thought to come from the manufacturing process, which leads Hung to suggest that the jade was transported as a raw material. “This of course implies movement of people and technology,” says Hung. Her findings are published in Proceedings of the National Academy of Sciences.

Roaming craftsmen

Hung suggests that the raw jade was carried by a few highly proficient, but itinerant, jade workers, who would set up camp and carve it into the lingling-o shapes preferred by the locals.

Finished ornaments were more commonly dated from 500 BC to 500 AD, when there was a flurry in trading activity in the region, and so more chance for a skilled jade worker to travel.

It was already known that obsidian was traded widely across Southeast Asia.

Hung suggests that this trading carried language with it. Today, Austronesian languages are spoken by about 350 million people in Southeast Asia and Oceania. The languages are thought to have started spreading as a people migrated from Taiwan to the Philippines 4,000 years ago. And the distribution of these languages closely mirrors the distribution of Fengtian jade, says Hung.

Fengtian jade and the Austronesian Cham language are both found in southern Vietnam, for example, but not in northern Vietnam — even though northern Vietnam is closer to the Fengtian source.

Nicole Boivin, from the Leverhulme Centre for Human Evolutionary Studies at the University of Cambridge, UK, says that although trade was already widespread in this region at the time in question, using systematic scientific techniques, such as the electron probe microscope, has allowed Hung and her team to get a more detailed picture of what is happening.

“It’s great using scientific methodology to look at this methodically,” says Boivin, “They have really shown in great detail that something is going on.”

References
1. Hung, H.-C. et al. Proc. Nat. Acad. Sci. USA doi 10.1073/pnas.0707304104 (2007).

原文：http://www.nature.com/news/2007/071119/full/news.2007.268.html

A new model of proteins seeks to explain how enzymes extract energy form their vicinity and put it to use in regulating cell chemistry. Enzymes are huge protein molecules that play a crucial role in catalyzing chemical reactions among other molecules or atoms by lowering the energy barrier that would otherwise keep the reaction from happening. Enzymes can therefore be considered as energy-processing chemical-reaction-facilitating machines.

They are usually large, typically containing thousands of heavy (non-hydrogen) atoms, but of these only a few dozen atoms actually participate in the catalytic process. Addressing this important issue, a team of scientists at the Ecole Normale Superieure (Lyon, France) and the Ecole Polytechnique Federale de Lausanne (Switzerland) have concentrated on modeling the behavior of the stiff parts of the enzyme since they believe that some of the energy used in carrying out the catalytic task is stored not just as chemical energy (in the form of adenosine triphosphate, or ATP, the all-purpose “food” of cells) but also as mechanical energy in the form of a waggling or “breathing” motion in the stiffer parts of the enzyme.

Extending this research to proteins in general, Yves-Henri Sanejouand says that he and his colleagues would like to scrutinize in more detail the nonlinear process by which some proteins catch and store thermal energy from their environment and also how chemical energy can be turned into mechanical energy, such as in muscle contraction.

原文：http://www.aip.org/pnu/2007/split/846-2.html

It seems unlikely that a toddler would pass up a teddy bear for a hunk of metal. But in a new study, toddlers developed strong social bonds with robots, largely ignoring their traditional toys. The findings represent a step forward in human-robot interactions.People’s bonds with their pets tend to strengthen over time, but most available robots geared toward interacting with people, such as Sony’s mechanical puppy AIBO, have tended to lose their appeal within about 10 hours. Eager to break the so-called 10-hour barrier, Fumihide Tanaka, a robotics researcher at the University of California, San Diego (UCSD), and colleagues tested the Sony QRIO, a state-of-the-art humanoid robot that can recognize faces and respond to touch.

The researchers chose toddlers for the tests because they “have no preconceived notions of robots,” Tanaka says. Children at UCSD’s daycare facility interacted with QRIO for 45 sessions averaging 50 minutes each over 5 months. The sessions were videotaped, and student volunteers evaluated the closeness of the interactions. The team also gauged the children’s “haptic contact”–how much and where they touched the robot–and compared it with how they treated toys and other children.

During the first 27 sessions, the robot was responsive to the children, giggling when its head was touched. The children enjoyed interacting with the robot during this period, the team reports.

The researchers then restricted QRIO’s behavior to a more predictable, nonresponsive dance routine for 15 sessions, and children’s interest declined. At the end of the study, the team reinstated its full repertoire for three sessions, and interest picked up. Programming the robot to respond to the children was key to engaging them, the team reports online 5 November in the Proceedings of the National Academy of Sciences.

The children also came to prefer hugging QRIO more than they preferred hugging a teddy bear or an inanimate robot doll, and they touched QRIO carefully, in the same way that they touched other children, rather than bashing it as they did the doll.

Even though he sent a command to the robot about once every 2 minutes, Tanaka says “the results imply that current robot technology is surprisingly close to achieving [sustained] autonomous bonding and socialization with human toddlers.”

Other experts are more cautious. “The authors are drawing general conclusions … beyond what the data alone suggest,” says Nathan Freier, a technologist and social scientist at Rensselaer Polytechnic Institute in Troy, New York. According to Freier, “haptic contact …cannot stand alone as an indicator of bonding or socialization.” But he calls the study an “excellent foundation” for future studies into childhood development and technology design.

原文：http://sciencenow.sciencemag.org/cgi/content/full/2007/1105/2

这是Nature上最近的一篇科学新闻。有理论家认为暗能量是宇宙虚空的体现，或者说暗能量是不存在的。

As an alternative hypothesis, he suggests that our Galaxy might lie in a huge bubble of comparatively empty space. The denser area of space outside this bubble would then pull material towards it. To an observer inside the bubble, it would seem as though a dark-energy-like force was pulling the Universe apart.

研究文章：

1. Is the evidence for dark energy secure?
2. Extragalactic Radio Sources and the WMAP Cold Spot

A chart of the density of our Universe. Different colours have been used to show different types of galaxies; the black spaces show low-density gaps.Sloan Digital Sky Survey Team, NASA, NSF, DOE

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