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[阅读小分队] 【每日阅读训练第四期——速度越障20系列】【20-15】科技

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发表于 2013-6-18 19:15:16 | 显示全部楼层 |阅读模式
大家好,胖胖翔来啦!今天以生物类为主,生动有趣的文章!enjoy~
Part I: Speed

[Time 1]
Article 1
Sunflowers Do the Math
The spiraling shapes in cauliflower, artichoke, and sunflower florets (above) share a remarkable feature: The numbers of clockwise and counterclockwise spirals are consecutive Fibonacci numbers—the sequence 1, 1, 2, 3, 5, 8, and so on, so that each number is the sum of the last two. What's more, those spirals pack florets as tight as can be, maximizing their ability to gather sunlight for the plant. But how do plants like sunflowers create such perfect floret arrangements, and what does it have to do with Fibonacci numbers? A plant hormone called auxin, which spurs the growth of leaves, flowers, and other plant organs, is the key: Florets grow where auxin flows. Using a mathematical model that describes how auxin and certain proteins interact to transport each other around inside plants, researchers could predict where the hormone would accumulate. Simulations of that model reproduced patterns exactly matching real "Fibonacci spirals" in sunflowers, the team reports this month in Physical Review Letters. Based on their results, the researchers suggest that such patterns might be more universal in nature than previously thought, so keep an eye out: Fibonacci numbers might be spiraling in every direction.
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Source:
http://news.sciencemag.org/sciencenow/2013/06/scienceshot-sunflowers-do-the-ma.html

[Time 2]
Article 2
Fatherhood From Beyond the Grave
Men who become dads in their 50s may feel studly, but they've got nothing on the wild guppy. New research shows that the male Trinidadian guppy (Poecilia reticulata), the ancestor of the common aquarium resident, can become a father long after death. Scientists spiked a guppy-free stretch of stream in Trinidad with 38 male and 38 female fish. Every month, they used butterfly nets and traps baited with dog food to capture the guppies in the study area—which was bounded by waterfalls, ensuring no immigrants or escapees—and then analyzed their DNA. The survey showed that almost 14% of the 540 tallied births took place after dad had died, and that a male guppy could become a father 8 months, roughly 75 years in human terms, after his demise. That allowed half of the fish to sire offspring from beyond the (watery) grave, the team reports online today in the Proceedings of the Royal Society B. The male has the female to thank for this supernatural ability. A female guppy can store her consort's sperm for months in a tiny pocket inside her ovaries, which is lucky, because females live much longer than males. The arrangement benefits both sexes: Females can have babies even if the dating scene is grim, and males can reproduce for longer than their lifespan.

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Source:
http://news.sciencemag.org/sciencenow/2013/06/scienceshot-fatherhood-from-beyo.html

[Time 3]
Article 3
Selectively Targeting Aerosol Pollutants Could Reduce Climate Change

Cutting our overall use of fossil fuels has proved a daunting challenge, but it might be possible to get some relief from the effects of climate change by selectively reducing the particulate pollution we produce. Recent research suggests that if we can clean up diesel engines and primitive cookstoves in India and China, for example, that could delay the effects of greenhouse-gas buildup even if pollution from coal-fired power plants persists. A study released last week concludes that if every country were to do what California has done in the last couple of decades to clean up diesel emissions, it would slow down global warming by 15 percent. Reducing similar pollution from sources such as ships and cookstoves—which weren’t included in the study—could help even more.
The study comes as governments in India and China are deciding how to address their increasing pollution, which can contribute to fatal human health problems. Over the weekend, state-controlled media in China announced new pollution rules targeting both power plants and emissions from cars and trucks.
Aerosol pollutants such as sulfur dioxide, soot, and ozone are all bad for human health, but they have different effects on the climate. “Some of the aerosols are warming the planet, and some are cooling the planet,” says Phil Rasch, a fellow at the Pacific Northwest National Laboratory in Richland, Washington. For example, sulfates that form from coal-plant exhaust reflect sunlight back into space, acting to shade the planet and cool it off. Black-carbon particles from diesel exhaust, on the other hand, absorb sunlight and heat up, warming the atmosphere.
When you add them together, we think that on balance they’re cooling the planet,” Rasch says. That is, they mask some of the temperature increase that would have occurred as a result of carbon dioxide emissions, the main human contribution to global warming. But this effect would be more significant if the particulates that help heat up the atmosphere were removed. “If we could get rid of the ones that are warming the planet,” he says, “then that would buy us some more time.”

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[Time 4]

Rasch says that several other recent papers have asked the question posed in the one that came out this week: “What would happen if we immediately got rid of only the black-carbon aerosols?” He says doing that “might lead to a cooling of the planet by half a degree to a degree Celsius.” He notes, however, that the impact on temperature is hard to pin down. For one thing, pollution affects clouds and rainfall, which have complicated effects on climate.
One advantage of going after black carbon is that the effects would be almost immediate. These pollutants fall out of the atmosphere in the course of a few days or weeks, so once emissions stop, the air quickly clears. Carbon dioxide, on the other hand, stays in the atmosphere for hundreds of years.
Of course, it’s ultimately important to reduce all pollution, since it kills millions of people a year. “We want to cut down on pollution in every way that we can because of human health,” says Lai-yung Ruby Leung, a fellow at PNNL, who is one of the authors of the black-carbon study that came out his week. Selectively reducing pollutants as a way of countering global warming “is an important strategy we can think about,” she says, “but it needs to be carefully done.” Rasch emphasizes speeding up reduction of the pollutants that warm the planet, not necessarily putting off regulations to reduce the ones that cool it.
Leung says the research suggests at the very least that as countries clean up sulfates from power plants, they should make sure to cut down on diesel emissions at the same time. Just reducing the sulfates would cause the planet to warm up.

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Source:
http://www.technologyreview.com/news/515961/selectively-targeting-aerosol-pollutants-could-reduce-climate-change/

[Time 5]
Article 4
Fast Break
Metastatic cells move through tight spaces more quickly than ordinary cells
Most cancer deaths are caused by metastatic tumors, which break free from the original cancer site and spread throughout the body. Many of the genetic changes that allow cells to become metastatic have been studied extensively, but it has been more difficult to study the physical changes that contribute to this process.
MIT researchers have now developed a way to study, on a large scale, how changes in key physical properties of cancer cells allow them to migrate to new sites. Scientists have previously observed that cells with higher metastatic potential are more deformable than nonmetastatic cells, but the MIT team found that cancer cells also seem to traverse narrow channels more easily because they encounter less friction, which may help them travel through blood vessels to new tumor sites.
"Our measurements provide an additional perspective on cell properties," says Sangwon Byun, an MIT postdoc and lead author of a paper describing the findings in the Proceedings of the National Academy of Sciences.
The system that Byun and colleagues used to study the cancer cells is based on a device that Scott Manalis, a member of MIT’s Koch Institute for Integrative Cancer Research and a professor of biological engineering, developed to measure the mass of a single cell. For the new study, Byun, Manalis, and colleagues adapted the system to measure a cell’s velocity as it traveled through a narrowly constricted channel about 50 microns long, allowing them to estimate the cell’s deformability and susceptibility to friction.
They found that metastatic cells not only were more deformable than nonmetastatic cells but also traveled faster. "It seems that the cells experience less friction, making it easier for them to get through the channels," Byun says. The researchers are now using their system to detect the circulating tumor cells (CTCs) that are found in cancer patients’ blood at levels ranging from a few to several thousand per milliliter. After capturing those cells, scientists could do many more tests on them, including analyses of genes expressed and proteins produced, to learn more about how they break free from tumors. Manalis and colleagues also plan to study physical changes that occur in cells as they go through the epithelial-mesenchymal transition, a process that allows cancer cells to stop sticking together and become mobile.

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Source:
http://www.technologyreview.com/article/515416/fast-break/
Part II: Obstacle
Article 5
Computer Scientists Get Wet

In the summer of 2008, when Wired magazine ran a cover story titled "The End of Science," former Editor-in-Chief Chris Anderson wrote, "The new availability of huge amounts of data, along with the statistical tools to crunch these numbers, offers a whole new way of understanding the world. Correlation supersedes causation, and science can advance even without coherent models, unified theories, or really any mechanistic explanation at all. There's no reason to cling to our old ways. It's time to ask: What can science learn from Google?"
Five years later—not a lot of time, admittedly—data, computers, and statistical tools are indeed having a major impact on science. In the domain sciences—traditional fields like physics, biology, and chemistry—the old ways are holding. People still care about causation, mechanisms, and coherent theories, but in many disciplines, researchers are looking to supplement those traditional elements of science, harvesting gains from the data deluge by, in effect, learning from Google. In May, Science Careers wrote about some of these "pi-shaped" researchers, who have added computer science techniques to the techniques of their various native fields.
But it's also possible to get pi-shaped from the other end—the computer science end. By adding fundamentals of  biology to their computer science training, more than a few native computer scientists are contributing—and preparing themselves to contribute—to the advancement of the life sciences (among other fields), laying foundations for  new branches of study. It is indeed a promising approach, but there is still much work to be done—satisfying work, one pioneer says.
Biology for computer scientists
Lawrence Hunter graduated from Yale University with a Ph.D. in computer science in 1989, during what he calls "the AI winter," a period of reduced funding and interest in artificial intelligence—the field he had been studying. So he went in a new direction, joining the fledgling Human Genome Project as a programmer. "I had studied biology till tenth grade, which meant I had no modern biology at all," he says. Hunter attended weekly genomics seminars at the U.S. National Library of Medicine (NLM) where he worked. As his own coding began yielding results—for example, a list of genes that allowed eukaryotes to diverge from prokaryotes—he began to take biology more seriously. He asked a lot of questions and read all of the papers that his colleagues suggested. "I spent a decade learning by osmosis from all the brilliant people around me," says Hunter, who is considered one of the founders of bioinformatics.
Hunter is now the director of the computational bioscience program at the University of Colorado School of Medicine. He has published seminal papers in his field and written a life sciences textbook aimed at non-life scientists: The Processes of Life: An Introduction to Molecular Biology.
Hunter believes that computer scientists can cross over at any career stage. "Studying CS is like learning to play a musical instrument and can't be done quickly. Biology can be learned by reading and remembering," he says.
Rewiring cells
Synthetic biology, which involves designing and building genetic constructs and testing them in living cells, requires wet lab skills. "The combination of quantitative abilities and experimental biology skills is very valuable in synthetic biology," says Timothy Lu of Massachusetts Institute of Technology's (MIT's) Research Laboratory of Electronics, an interdepartmental center where "research encompasses an extensive range of natural and man-made phenomena."
Nevertheless, Lu, who has an undergraduate degree with majors in electrical engineering and computer science (and minors in biomedical engineering and biology), doesn't make bench experience a prerequisite for his incoming graduate students. He just expects them to be enthusiastic about learning biology.
That approach worked for Samuel Perli, a 5th-year doctoral candidate in Lu's lab who had no college-level biology to speak of before he started his graduate studies in computer science at MIT. While doing research on wireless networks, he attended a talk by the director of the institute's Synthetic Biology Center. He was inspired to sign up for "Introduction to Experimental Biology," after squaring away the requirements for his master's degree. That semester, he read books, research papers, and popular articles on biology, and had conversations with friends who did biology research. He was following in the footsteps of the academics who had created this field less than 2 decades ago. "I love the fact that once I program and modify a single living cell, I can have millions of similar cells by just growing them up," says Perli, who is now at the bench almost every day.
At Harvard Medical School, Pamela Silver is a founding member of the Department of Systems Biology, which she describes as a field that among other things "seeks to understand what evolution gave us and how we got to where we are." Though we have genomic information about various organisms, we still have to synthesize it to understand how the whole organism or system functions, she explains in this YouTube video. Similar to Lu, she doesn't require incoming researchers to have a background in cell biology.

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Source:
http://sciencecareers.sciencemag.org/career_magazine/previous_issues/articles/2013_06_14/caredit.a1300123

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发表于 2013-6-18 19:20:35 | 显示全部楼层
又沙发!谢谢翔翔~

文章很有意思~ 生物是我的最爱啊。

交作业
Time1 1'04"
Time2 1'18"
Time3 1'59"
Time4 1'22"
Time5 1'58"
Obstacle 4'37"
发表于 2013-6-18 19:51:30 | 显示全部楼层
楼主辛苦~

————————————————————
Speed
00:58
01:09
01:41
01:20
01:36

Obstacle
05:28
Main idea: New relationship between CS and science
Attitude:   Positive
Structure:
              1) Argument---CS now are having a major impact on science.
              2) Example1---Lawrence Hunter
              3) Example2---Timothy Lu and Pamela Silver



发表于 2013-6-18 19:53:29 | 显示全部楼层
辛苦楼主~
发表于 2013-6-18 20:24:22 | 显示全部楼层
占座占座
1'05"
1'20"
1'45"
1'10"
1'50"

4'50"
发表于 2013-6-18 20:32:44 | 显示全部楼层
占位~~~~
发表于 2013-6-18 20:37:11 | 显示全部楼层
占一个~~~ppx辛苦啦
发表于 2013-6-18 20:46:53 | 显示全部楼层
还有没有首页~~
---------------------------------------------------------
1'27''
1'38''
2'15''
1'57''
2'16''

6'47''
发表于 2013-6-18 21:14:19 | 显示全部楼层
1:15 sunflowers create floret arrangement becuase when floret grows auxin grow,
1:34, guppy can become father after death since female guppy can store sperms for months
2:06, china and india are targeting to reduce poullants emmission A to prevent the planet from warming up
1‘36  china do so not only to cool off the planet althoght it is one of the choices off cooling the planet, but also to benefit human's health
2:00 MIT's reserch on Metastatic cells that travel very fast in blooy vein

越障 5:16
发表于 2013-6-18 21:40:24 | 显示全部楼层
谢谢PPX~~
哀,又落到第二页了...

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