【每日阅读训练第四期——速度越障12系列】【12-11】科技

2012Michelle

哇，大米真是很幸运哦，当完圣诞老人又来扫尾迎新，陪大家度过2012年最后一天、迎接2013年的第一天。

在这里大米祝大家在新的一年里万事顺意、考试拿高分、申请到如意的学校。

总之，想什么有什么。

要达成愿望不能偷懒啊，元旦也要认真学习哦。今天的速度和越障难度恢复（上次作业有同学反馈VOA太简单了，呵呵）。

本次的阅读让我们来看看科学界2013年需要展望哪些故事？非洲发现了最什么的自然颜色？科学家又挖到啥化石了？当然，还有老话题，关于物种的灭绝。。。吼吼~

附送一篇阅读：人之初性本善还是性本恶咧？

5 Science Stories to Watch in 2013
[attachimg=706,600]112375[/attachimg]
【Time1】
Over the past year, we’ve seen a ton of scientific milestones and discoveries of historic importance, from the discovery of the Higgs Boson to the landing of a mobile laboratory on Mars. Science, though, is defined by its relentless march forward: No matter how much we learn, there are always more questions to answer. So, after our roundup of 2012′s most surprising (and significant) scientific events, we bring you the most exciting studies, projects and science developments we’ll be watching for in 2013.

1. Comet Ison: Back in September, a pair of Russian astronomers discovered a new comet heading in our direction. At the time, it was just a faint blip detectable only with the most sophisticated telescopes, and it was unclear how visible it would become during its approach. Now, though, astronomers are predicting that when it passes by us and closely orbits the sun in November and December of 2013, it could be the astronomical sight of our lifetimes. “Comet Ison could draw millions out into the dark to witness what could be the brightest comet seen in many generations—brighter even than the full Moon,” astronomer David Whitehouse writes in The Independent. One thing’s for sure: we’ll be watching.
[attachimg=705,507]112376[/attachimg]
2. Lake Vostok: For more than a decade, a team of Russian scientists has worked to drill nearly 12,000 feet down into Antarctica’s icy depths with a single purpose: to obtain samples from the ultra-deep isolated subglacial lake known as Lake Vostok. After barely reaching the water’s surface last Antarctic summer, they now plan to return at the end of 2013 to drill fully into the lake and use a robot to collect water and sediment samples. The lake may have been isolated for as long as 15 to 25 million years—providing the tantalizing potential for long-term isolated evolution that could yield utterly strange lifeforms. The lake could even serve as a model for the theoretical ice-covered oceans on Jupiter’s moon Europa, helping us better understand how evolution might occur elsewhere in the solar system.

Rival American and British teams were also racing to probe the depths of other subglacial lakes in search of life—the American team’s efforts to reach subglacial Lake Whillans is expected to meet with success this January or February, while the British have been forced to cease their drilling efforts into subglacial Lake Ellsworth due to technical difficulties.
【400】

【Time2】
3. Algae Fuel: Experts predict that 2013 will be the year when vehicle fuels derived from algae finally take off. A handful of biofuel stations in the San Francisco area started selling algae-based biodiesel commercially for the first time last month, and after the product met state fuel standards, the pilot program is expected to be expanded shortly. Because algae use less space, grow more quickly and can be more efficiently converted into oil than conventional crops used for biofuels, advocates are excited about the possibility that algae-based fuels could wean us off petroleum without using up precious food crops.

4. Cosmic Microwave Background: Energy left over from the Big Bang still radiates through the universe—and the European Space Agency’s plans to use the Planck satellite to measure this energy more precisely than ever before could help us better understand the formation of the universe. The 1965 measurement of this microwave energy first supported the concept of the Big Bang, and subsequent examination of variations in the radiation has led to more sophisticated theories about our universe’s earliest days. The Planck satellite, launched in 2009, has already collected a wide range of valuable astronomical data and images, but plans to release all this info in early 2013 has the cosmology world all atwitter.

5. Supercomputers to the Rescue: A number of supercomputers around the world could have a remarkable impact at solving problems in health, the environment and other fields over the next year. Yellowstone, a 1.5 petaflops cluster computer in Wyoming, was installed this past summer and will spend 2013 crunching numbers (1.5 quadrillion calculations per second, to be exact) to refine climate models and help us better understand how storms and wildfires move across the planet. Meanwhile, Watson, IBM’s world-famous Jeopardy-winning supercomputer, is currently being trained by doctors to recognize medical symptoms and serve as a diagnostic tool, providing treatment options based on case histories and clinical knowledge. So far, the computer has been trained to recognize breast, lung and prostate cancers.
【335】

This African Fruit Produces the World’s Most Intense Natural Color
[attachimg=688,602]112377[/attachimg]
【Time3】
The tiny, rock-hard fruits of Pollia condensata, a wild plant that grows in the forests of Ethiopia, Mozambique, Tanzania and other African countries, can’t be eaten raw, cooked or turned into a beverage. In Western Uganda and elsewhere, though, the plant’s small metallic fruits have long been used for decorative purposes because of an unusual property: They stay a vibrant blue color for years or even decades after they’ve been picked. A specimen at the Kew Botanical Gardens in London that was gathered in Ghana in 1974 still retains its iridescent hue.

Intrigued, a team of researchers from Kew, the University of Cambridge and the Smithsonian Natural History Museum decided to look into how this plant produces such a dazzling and persistent color. When they attempted to extract a pigment to study, though, they were surprised to discover the fruit had none.

When they examined P. condensata on a cellular level, they realized that the fruit produces its characteristic color through structural coloration, a radically different phenomenon that is well-documented in the animal kingdom but virtually unknown in plants. They determined that the fruit’s tissue is more intensely colored than any previously studied biological tissue—reflecting 30 percent of light, as compared to a silver mirror, making it more intense than even the renowned color of a Morpho butterfly’s wings. Their findings were revealed in a new study published today in the Proceedings of the National Academy of Sciences.

The vast majority of colors in the biological world are produced by pigments—compounds produced by a living organism that selectively absorb certain wavelengths of light, so that they appear to be the color of whichever wavelengths they reflect. For example, most plants are green because of the pigment chlorophyll, used in photosynthesis, which absorbs most wavelengths of visible light except green, reflecting that color into our eyes. As a consequence, plant colors created by pigmentation appear to be the exact same hue no matter which angle we view them from, and the color degrades when the plant dies.
【338】

【Time4】
P. condensata, however, produces its vibrant blue via tiny, nanoscale-size cellulose strands that are stacked inside its skin. These strands are arranged in layers of twisting, arced helix shapes, which interact with each other to scatter light and produce the fruit’s deep blue coloration. Here’s a view of the fruit through an electron microscope, revealing the presence of the color on a cellular level:
[attachimg=694,652]112378[/attachimg]

These strands also give the plant an even more fascinating quality, something that can (unfortunately) only be appreciated in person: Depending on how you hold the fruit and from what angle you view it, each of its skin cells actually appears to change color. This is because the distance between the stacked nanoscale fibers varies from cell to cell, so each cell produces a slightly different hue, reflecting light either to the left or right, depending on your vantage point. This accounts for its striking, pixellated appearance:
[attachimg=703,504]112379[/attachimg]

The reason the fruit’s color lasts so remarkably long, it turns out, is because its color is built into its structure, rather than relying on pigments that can degrade over time. Researchers have reported seeing vibrant blue fruits hanging on dried-up, dead P. condensata stems in the field.

The research team also took a stab at explaining why the plant would go to such trouble to evolve a striking color—deception. By imitating the appearance of a juicy, nutritious plant, the color can trick birds and animals into eating the fruit, thereby widely dispersing the seeds inside when they defecate.

Although using animals for dispersal is a strategy common to many plants, most are forced to devote precious calories to produce a sweet, fleshy pulp. P. condensata, however, is able to spread its seeds simply by showing its true colors.
【291】

Researchers Find First Evidence of Ice Age Wolves in Nevada
[attachimg=651,428]112380[/attachimg]
【Time5】
A University of Nevada, Las Vegas research team recently unearthed fossil remains from an extinct wolf species in a wash northwest of Las Vegas, revealing the first evidence that the Ice Age mammal once lived in Nevada.

The metapodial, or foot bone, was uncovered late last year by UNLV geologist Josh Bonde during a survey of the Upper Las Vegas Wash. They have now confirmed that the bone comes from a dire wolf.

The discovery site is near the proposed Tule Springs Fossil Beds National Monument, a fossil-rich area known for its diversity and abundance of Ice Age animal remains. Scientists estimate the fossil to be 10,000 to 15,000 years old during the Late Pleistocene period.

"Dire wolves are known to have lived in almost all of North America south of Canada, but their historical presence in Nevada has been absent until now," said Bonde, a UNLV geology professor. He was a Ph.D. student at the university when he discovered the bone.

"The Tule Springs area has turned up many species, but it's exciting to fill in another part of the map for this animal and reveal a bit more about the Ice Age ecosystem in Southern Nevada."

The dire wolf, a larger relative of the gray wolf, was present in much of North and South America for more than a million years. Scientists theorize that competition from other wolf species and a possible food scarcity led to its extinction roughly 10,000 years ago.

Foot bones of the extinct dire wolf are difficult to distinguish from those of the gray wolf. Researchers conclude bone is likely from a dire wolf because of the abundance of dire wolf fossils―and scarcity of gray wolf fossils―in similar-aged excavation sites throughout the Southwest.
【289】

【Rest】
Fossil remains of dire wolves are abundant in the La Brea tar pits and have been found in other Southwestern states. Many of the same species of Ice Age animals found at La Brea have also been recovered in the Las Vegas Valley, including Columbian mammoths, camels, horses, bison, and ground sloths.

"This discovery helps flesh out Southern Nevada's Pleistocene ecosystem and shows that there are still important discoveries to be made in the Upper Las Vegas Wash," said UNLV geology professor Steve Rowland, a collaborator with Bonde on the study of local Ice Age fossils. "To understand why certain species became extinct and others did not, we need to learn as much as possible about predatory habits and which species were especially sensitive to changes in the environment."

The announcement comes on the heels of a recent discovery in the same wash of a saber-tooth cat by researchers from the San Bernardino County Museum. Like dire wolves, saber-tooth cats were Pleistocene predators that had been conspicuously absent from the Southern Nevada fossil record.

According to Rowland, Tule Springs was a spring-fed, swampy area during periods of the Late Pleistocene, an ideal spot for plant-eating animals and their carnivorous predators.

The recent discoveries come exactly 50 years after scientists conducted a 'big dig' at Tule Springs, revealing the site to be rich with Ice Age fossils.

"Tule Springs likely had the highest density of large animals in the area during the Late Pleistocene, and the marshy environment was very good for preserving at least some of the bones and teeth of animals that died there," said Rowland.

"In the 50 years since the 'big dig,' the scientists have confirmed that humans interacted with Ice Age animals. We now have a new list of questions about life and death in the Pleistocene, and a new tool kit of research techniques to help us get the answers."

The identity of the find was confirmed by Xiaoming Wang of the Los Angeles County Museum of Natural History, an expert on extinct species of the dog family. Bonde has been surveying the Tule Springs area since 2007, and he and a group of UNLV undergraduate studentss are prospecting for more fossils.

The center of the original 'big dig' is on the same parcel of land where Bonde discovered the wolf fossil.

The dire wolf bone, in addition to other bones collected by UNLV researchers, are cataloged, studied, and stored at UNLV.
【407】

【Obstacle】
Evidence Contradicts Idea That Starvation Caused Saber-Tooth Cat Extinction

Dec. 26, 2012 — In the period just before they went extinct, the American lions and saber-toothed cats that roamed North America in the late Pleistocene were living well off the fat of the land.

That is the conclusion of the latest study of the microscopic wear patterns on the teeth of these great cats recovered from the La Brea tar pits in southern California. Contrary to previous studies, the analysis did not find any indications that the giant carnivores were having increased trouble finding prey in the period before they went extinct 12,000 years ago.

The results, published on Dec. 26 in the scientific journal PLOS ONE, contradicts previous dental studies and presents a problem for the most popular explanations for the Megafaunal (or Quaternary) extinction when the great cats, mammoths and a number of the largest mammals that existed around the world disappeared.

"The popular theory for the Megafaunal extinction is that either the changing climate at the end of the last Ice Age or human activity -- or some combination of the two -- killed off most of the large mammals," said Larisa DeSantis, assistant professor of earth and environmental sciences at Vanderbilt, who headed the study. "In the case of the great cats, we expect that it would have been increasingly difficult for them to find prey, especially if had to compete with humans. We know that when food becomes scarce, carnivores like the great cats tend to consume more of the carcasses they kill. If they spent more time chomping on bones, it should cause detectable changes in the wear patterns on their teeth."

In 1993, Blaire Van Valkenburgh at UCLA published a paper on tooth breakage in large carnivores in the late Pleistocene. Analyzing teeth of American lions, saber-tooth cats, dire wolves and coyotes from La Brea, she found that they had approximately three times the number of broken teeth of contemporary predators and concluded, ." ..these findings suggest that these species utilized carcasses more fully and likely competed more intensely for food than present-day large carnivores."

The latest study uses a new technique, called dental microwear texture analysis (DMTA), developed by co-author Peter Ungar at the University of Arkansas. It uses a confocal microscope to produce a three-dimensional image of the surface of a tooth. The image is then analyzed for microscopic wear patterns. Chowing down on red meat produces small parallel scratches. Chomping on bones adds larger, deeper pits. Previous methods of dental wear analysis relied on researchers to identify and count these different types of features. DMTA relies on automated software and is considered more accurate because it reduces the possibility of observer bias.

DeSantis and Ungar, with the assistance of Blaine Schubert from East Tennessee State University and Jessica Scott from the University of Arkansas, applied DMTA to the fossil teeth of 15 American lions (Panthera atrox) and 15 saber-tooth cats (Smilodon fatalis) recovered from the La Brea tar pits in Los Angeles.

Their analysis revealed that the wear pattern on the teeth of the American lion most closely resembled those of the present-day cheetah, which actively avoids bones when it feeds. Similarly, the saber-tooth cat's wear pattern most closely resembled those of the present-day African lion, which indulges in some bone crushing when it eats. (This differs from a previous microwear study using a different technique that concluded saber-tooth cats avoided bone to a far greater extent.)

The researchers examined how these patterns changed over time by selecting specimens from tar pits of different ages, ranging from about 35,000 to 11,500 years ago. They did not find any evidence that the two carnivores increased their "utilization" of carcasses throughout this period. If anything, their analysis suggests that the proportion of the carcasses that both kinds of cats consumed actually declined toward the end.

The researchers acknowledge the high rate of tooth breakage reported in the previous study, but they argue that it is more likely the result of increased breakage when taking down prey instead of when feeding.

"Teeth can break from the stress of chewing bone but they can also break when the carnivores take down prey," DeSantis pointed out. Species like hyenas that regularly chew and crack bones of their kills are as likely to break the rear teeth they use for chewing as their front canines. Species like the cheetah, however, which avoid bones during feeding are twice as likely to break canines than rear teeth. This suggests that they are more likely to break canines when pulling down prey.

The researchers report that previous examinations of the jaws of the American lions and saber-tooth cats from this period found that they have more than three times as many broken canines and interpret this as additional evidence that supports their conclusion that most of the excess tooth breakage occurred during capture instead of feeding.

In addition, the researchers argue that the large size of the extinct carnivores and their prey can help explain the large number of broken teeth. The saber-toothed cats were about the size of today's African lion and the American lion was about 25 percent larger. The animals that they preyed upon likely included mammoths, four-ton giant ground sloths and 3,500-pound bison.

Larger teeth break more easily than smaller teeth. So larger carnivores are likely to break more canine teeth when attempting to take down larger prey, the researchers argue. They cite a study that modeled the strength of canine teeth that found the canines of a predator the size of fox can support more than seven times its weight before breaking while a predator the size of lion can only support about four times its weight and the curved teeth of the saber-toothed cats can only support about twice its weight.

"The net result of our study is to raise questions about the reigning hypothesis that "tough times" during the late Pleistocene contributed to the gradual extinction of large carnivores," DeSantis summarized. "While we cannot determine the exact cause of their demise, it is unlikely that the extinction of these cats was a result of gradually declining prey (due either to changing climates or human competition) because their teeth tell us that these cats were not desperately consuming entire carcasses, as we had expected, and instead seemed to be living the 'good life' during the late Pleistocene, at least up until the very end."
【1062】

【New Year Gift】
Are Babies Born Good?

New research offers surprising answers to the age-old question of where morality comes from [attachimg=759,388]112381[/attachimg]

Smithsonian magazine, January 2013, Subscribe
（文章未正式发表，只是提交状态。一下摘抄了文章的一部分，如果同学们感兴趣的话，可以戳右边的链接读全文：http://www.smithsonianmag.com/science-nature/Are-Babies-Born-Good-183837741.html?c=y&page=1）

Arber Tasimi is a 23-year-old researcher at Yale University’s Infant Cognition Center, where he studies the moral inclinations of babies—how the littlest children understand right and wrong, before language and culture exert their deep influence.“What are we at our core, before anything, before everything?” he asks. His experiments draw on the work of Jean Piaget, Noam Chomsky, his own undergraduate thesis at the University of Pennsylvania and what happened to him in New Haven, Connecticut, one Friday night last February.

It was about 9:45 p.m., and Tasimi and a friend were strolling home from dinner at Buffalo Wild Wings. Just a few hundred feet from his apartment building, he passed a group of young men in jeans and hoodies. Tasimi barely noticed them, until one landed a punch to the back of his head.

There was no time to run. The teenagers, ignoring his friend, wordlessly surrounded Tasimi, who had crumpled to the brick sidewalk. “It was seven guys versus one aspiring PhD,” he remembers. “I started counting punches, one, two, three, four, five, six, seven. Somewhere along the way, a knife came out.” The blade slashed through his winter coat, just missing his skin.

At last the attackers ran, leaving Tasimi prone and weeping on the sidewalk, his left arm broken. Police later said he was likely the random victim of a gang initiation.

After surgeons inserted a metal rod in his arm, Tasimi moved back home with his parents in Waterbury, Conn­­ecticut, about 35 minutes from New Haven, and became a creature much like the babies whose social lives he studies. He couldn’t shower on his own. His mom washed him and tied his shoes. His sister cut his meat.

Spring came. One beautiful afternoon, the temperature soared into the 70s and Tasimi, whose purple and yellow bruises were still healing, worked up the courage to stroll outside by himself for the first time. He went for a walk on a nearby jogging trail. He tried not to notice the two teenagers who seemed to be following him. “Stop ca­tastrophizing,” he told himself again and again, up until the moment the boys demanded his headphones.

The mugging wasn’t violent but it broke his spirit. Now the whole world seemed menacing. When he at last resumed his morality studies at the Infant Cognition Center, he parked his car on the street, feeding the meter every few hours rather than risking a shadowy parking garage.

“I’ve never been this low in life,” he told me when we first met at the baby lab a few weeks after the second crime. “You can’t help wonder: Are we a failed species?”

At times, he said, “only my research gives me hope.”

【450】

yangreat

感谢啊！

2012Michelle

晕，LS沙发帝太厉害了！！

涂涂Claire

这一周过的可真快呀……又到科技文了呢……

——————————————————————————————补作业———————————————————————————
Time 1: 2'27"
Time 2: 2'17"
Time 3: 1'53"
Time 4: 1'35"
Time 5: 1'13"
Obstacle: 5'47"

阿菜hrf

唉，12年怎么又过去了呢？说好的世界末日呢？
1'50''
1'31''
2'23''
1'36''
1'29'' 作为一个文科生，现在越来越喜欢读科技文了啊
5‘54

annaliang2008

2'57
1'09
3'32
2'39
2'15
9'57

miffyhui

thx！占
祝大家新年快乐~~~
1’30”
1’48”
1’49”
1’48”
1’22”
6’02”

annysweety

谢谢大米的跨年盛宴！
anny很努力，希望2013年能考个理想的成绩，申请个理想的学校！
也祝福所有努力着的朋友们，新年顺顺利利！


3'37''(400)brightest comet, brighter then moon，million years ago water, to see life and conpare to ice-covered ocean of E.
2'26''(335)algae fuel expand use, better than other biofuel using crop. litter space, east converst. microwave measure energy to further know the space after big bang.super computer used in health and environment aspects.
2'24''(338)coloration tissure-intense color
2'50''(291)strand status -> intense color, different angle->different color. structure->long time color. intense color-> seed spread
4'25''(407+289)dire wolf bone found, lack of food and environment may be its extinction reason. need further study.
6'52''(1062)DMTA-> analyze tooth brakage->capture prey not feeding cause but not sure-> good life until very end of P period
2'36''(450)T meets two crime->are we a failedcreature-> answer may in his research

kevinlaci

1'18
1'45
1'46
1'38
1'18
5'33

铁板神猴

想说今天做三份来着，原来只有两份 都懒到一块儿去了~
今天就能把大米这份读了~~ wait for me!