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Official Weibo: http://weibo.com/u/3476904471 大家好!胖胖翔来了!最近阴雨绵绵，疾病横行，各位注重身体～今天的文章以生物为主，交叉了天文和建筑，速度第一篇的图片超霸气！enjoy~
Part I：Speaker 【Rephrase1】 Article 1 Astronaut Sounds Alarm On Asteroids At a symposium on the danger of asteroid impacts, Apollo astronaut Rusty Schweickart said it's time for the planet to develop a strategy should a big rock come our way. Clara Moskowitz reports. Transcript hided
[Dialog, 1: 33]
If a big asteroid with Earth’s name on it were to reach us unimpeded, well, we could go the way of the dinosaurs. So a group of astronauts is advising the U.N. on a plan to protect the planet. “This is taking responsibility for the survival of life on planet Earth.” Apollo astronaut Rusty Schweickart on October 25th, at a discussion of the issue at New York’s American Museum of Natural History, its dinosaur skeletons a reminder of the danger of being unprepared. Last week, the General Assembly approved a preliminary set of asteroid defense measures. For example, a system for nations to share info about incoming space rocks. And a coordinated mission to deflect any asteroids found to be on a collision course with Earth. “The biggest problem right now institutionally is…no government in the world today has explicitly assigned the responsibility for planetary deflection to any of its agencies.” “NASA does not have an explicit responsibility to deflect an asteroid, nor does any other space agency.” Ultimately, the Earth’s nations must work together to combat this extraterrestrial threat. Because when it comes to space rocks, they are definitely out there. —Clara Moskowitz Source: http://www.scientificamerican.com/podcast/episode.cfm?id=astronaut-sounds-alarm-on-asteroids-13-11-04
Part II：Speed 【Time 2】 Article 2 Ice proved cool way to move stones for Forbidden City Ice-lubricated sledges were the most efficient way to transport multi-tonne stones for Beijing’s centre.
Some of the largest stones used to construct Beijing’s Forbidden City beginning in 1406 were hauled from distant quarries on wooden sledges along ice roads, ancient Chinese documents have revealed. Calculations now reported in Proceedings of the National Academy of Sciences show that, on uneven, winding roads, this method is safer, more reliable and much easier than using wooden rollers or dragging the sledges over bare ground. The imperial palace and surrounding buildings in the Forbidden City, a complex that has long served as the figurative centre of China’s capital city, were built in the early 1400s, but construction in and around the complex continued to the late 1500s and beyond. Many of the largest stones in the complex came from a quarry located about 70 kilometres from Beijing, says Howard Stone, a fluid mechanicist at Princeton University in New Jersey, and a member of the team that performed the study. “You go to the Forbidden City and see these massive rocks, and you ask yourself: ‘How in the world did they ever move this rock here?’” he says. A few historians have briefly noted that some enormous stones in the Forbidden City had been transported by sledges pulled by teams of men in the depths of winter. But Jiang Li, a mechanical engineer at the University of Science and Technology Beijing, recently stumbled across a more-detailed description related to one particular stone in the complex. The ancient document reported that the monolith, a 49-cubic-metre slab estimated to weigh almost 112 tonnes, was hauled to Beijing in 1557 over the course of 4 weeks — which works out as an average speed of about 8 centimetres per second. Other blocks of rock were even heavier, Stone says. The documents, which were later translated into English, raised several questions. Foremost, says Stone, is why weren’t the monoliths transported on wheeled vehicles, which had been used in China since the fourth century bc? Moreover, he asks, was hauling sledges on an ice road the best method available? The first question is fairly easy to answer, says Stone. Even into the late 1500s, Chinese wheeled vehicles could not carry loads exceeding around 86 tonnes, necessitating the use of wooden sledges for larger burdens.
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【Time 3】
Head count Answering the second question takes a bit more analysis. For one thing, Stone notes, using wooden rollers — imagine telegraph-pole–sized tree trunks as large bearings — is tricky on winding roads. The technique also requires a smooth, hard surface to prevent the rollers from becoming mired. Dragging a 112-tonne sledge over bare ground would require more than 1,500 men, Stone and his colleagues estimate. Pulling the same sled across bare ice or across wet, wooden rails would require at least 330 men. But if the stone-burdened toboggan were hauled along an ice road lubricated by a film of water, the researchers say, fewer than 50 men would be needed to tow the load. Hauling massive stones long distances over ice roads “is an interesting and plausible idea”, says Michael Parker Pearson, an archaeologist at University College London. But although winters in northern China were typically cold enough to allow the use of ice-lubricated highways, other parts of the world where large stone monuments are found — Stonehenge is a prime example, he notes — did not have the consistently cold winters required to reliably employ the technique. The team’s results “are wonderful and well written”, but probably substantially underestimate the number of men needed to haul a 112-tonne sledge, says Thomas Mathia, an expert in tribology — the science of friction and lubrication — at the Lyon Central School in France. For example, the effort to get the sledge moving from a standstill is much larger than that needed to keep it moving. So, around two to three times more men would be needed to transport the stone-burdened sled than Stone and his colleagues estimate, he notes. Furthermore, that is over a flat roadway, says Mathia. To pull the sledge up a 10° slope, you would need another 270 people or so.
字数[299] Source: http://www.nature.com/news/ice-proved-cool-way-to-move-stones-for-forbidden-city-1.14090
【Time 4】 Article 3 Oil recovery may have triggered Texas tremors
First came reports of earthquakes caused by hydraulic fracturing and the reinjection of water during oil and gas operations. Now US scientists are reporting tremors may have been caused by the injection of carbon dioxide during oil production. The evidence centres on a sudden burst of seismic activity around an old oil field in the Permian Basin in northwest Texas. From 2006 to 2011, after more than two decades without any earthquakes, seismometers in the region registered 38 tremors, including 18 larger quakes ranging from magnitude 3 to 4.4, scientists report today in the Proceedings of the National Academy of Sciences. The tremors began just two years after injections of significant volumes of CO2 began at the site, in an effort to boost oil production. “Although you can never prove that correlation is equal to causation, certainly the most plausible explanation is that [the tremors] are related to the gas injection,” says Cliff Frohlich, a seismologist at the University of Texas Institute for Geophysics in Austin, who co-authored the study.
Seismic shift The earthquakes have rattled residents in the nearby town of Snyder and spurred questions about the link to oil and gas activity in the region, but the University of Texas researchers are the first to provide a detailed analysis of the situation. In addition to information from the main seismic array managed by the US Geological Survey, the researchers had access to more detailed data from the EarthScope USArray, a grid of moveable seismometers that has been sweeping across the country since 2004. The number of USArray seismometers in Texas peaked between 2009 and 2011, when some 80 instruments were operating there, compared to the usual six. As a result, the researchers were able to identify precise locations for 93 earthquakes between March 2009 and December 2010.
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【Time 5】
“Any time you are putting material into the ground, particularly under pressure, you are going to have the potential to break rock,” says Robert Balch, a geophysicist at the New Mexico Institute of Mining and Technology in Socorro. Nonetheless, Balch says, evidence of such earthquakes at one site in Texas is not likely to force a broader re-evaluation of the practice of injecting CO2. The data suggest that there is a previously unidentified fault running through the area, and that the CO2 injections effectively lubricate that fault, enabling slippage. (Scientists documented a series of earthquakes in the area from 1975 through 1982, but those tremors were linked to water injections, also intended to boost oil production.) Although the oil companies may have more detailed geologic data, Frohlich says that there isn’t enough publicly available geological information to determine exactly what is happening. “In most places either you don’t have information, or a lot of the information is proprietary,” he says. Nor is it clear why nearby oil fields that have also been injected with CO2 have not experienced similar seismic activity. Mark Zoback, a geophysicist at Stanford University in California, says that the paper highlights the inevitable dangers of injecting CO2 into the ground, whether the purpose is to increase oil production or to bury fossil-fuel emissions to limit their effect on the climate. Zoback co-authored a 2012 study suggesting that injecting CO2 into saline aquifers — one proposed method for large-scale storage of the gas — could destabilize undetected faults; the result could be earthquakes that are large enough to allow the stored CO2 to leak out. Longer term, he says, the bigger danger for CO2 sequestration is not the shaking of the ground but the integrity of the reservoir that is intended to hold the gas in place. “We just have to be proactive,” Zoback says. “We have to collect the data that we need to prevent this from happening, and then once we begin operations we have to do the monitoring.”
字数[334] Source: http://www.nature.com/news/oil-recovery-may-have-triggered-texas-tremors-1.14088
【Time 6】 Article 4 Butterfly Study Shows Genomes Change in Bits and Pieces at First
For centuries, biologists have compared the looks and behaviors of closely related species to get a sense of their evolutionary history. Now, researchers are tracing that history in their genomes as well. They find that just a few regions of the genome drive the separation of incipient species early on, but that over time, lots of the genome gets involved in distinguishing the two. To study genome evolution, scientists sequenced 10 genomes from each of three species of a colorful tropical butterfly called Heliconius (pictured). They assessed the differences in the bases, the letters that make up DNA, keeping tabs on where those differences appeared in the genome and how many existed among the three species. They found that the two closest relatives, H. cydno—which has a white band on its wings—and H. pachinus—which has yellow bands—had just 12 small regions where they were different, for a total of 165,000 bases. They split apart 450,000 years ago. Eight of those regions coincided with genes important for setting the color pattern, according to a study published today in Cell Reports. The third, H. melpomene, with its red and yellow stripes, is 1 million years older and in that time, hundreds of differences had accumulated, spread across tens of millions of bases. It seems that evolution starts out slowly, with just a few key differences appearing, but then snowballs with differences accumulating at a faster rate over time.
字数[240] Source: http://news.sciencemag.org/biology/2013/10/scienceshot-butterfly-study-shows-genomes-change-bits-and-pieces-first
Part III： Obstacle
【Paraphase7】
Article 6
Syria’s Polio Outbreak Is a Reminder of the Disease’s Power The crippling virus has been almost eliminated—but it’s just resurfaced in Syria.
Polio has returned to Syria, which had been free of the potentially paralyzing and at times fatal disease since 1999. “There are ten cases confirmed right now in the Deir Al Zour province” in northeast Syria and 12 more suspected cases, says Oliver Rosenbauer, spokesman for the World Health Organization’s Global Polio Eradication Initiative. The cases in Syria are mostly among children who are age two or younger. In this conflict-ridden country, it has been difficult to reach all children for immunization. No one can say how the disease reached Syria, but what the outbreak shows, says Rosenbauer, is "that this is an epidemic-prone disease.” There is worry that the highly infectious disease will spread farther, as people move in and out of the area to other parts of the country and across borders to refugee camps and nearby countries. “The whole region is now at risk,” Rosenbauer says. To prevent that, response to the outbreak has already begun. Last month, shortly before the polio cases were confirmed, Syria launched a previously planned vaccination program to inoculate 1.6 million children throughout the country against polio, measles, mumps, and rubella. According to WHO, vaccinations in the Deir Al Zour province are being implemented. In addition, plans are under way to coordinate immunization and other outbreak response programs in Iraq, Jordan, Lebanon, Gaza, West Bank, Southern Turkey, and Egypt. “What we’re seeing is a lot of momentum and recognition that this is a major risk that needs to be addressed,” says Rosenbauer. “Everyone is pulling together to help make it happen.” In the rest of the world, progress has been made but there is still work to be done. The disease is now endemic in only three countries around the globe—Afghanistan, Nigeria, and Pakistan—and its incidence has decreased by more than 99 percent from an estimated 350,000 cases in 1988. ("Endemic" is the term used to describe countries with an ongoing incidence of the disease.) But we're not quite there yet, as this year's spring outbreaks in previously polio-free Somalia and Kenya reminded us. In addition, the discovery of sewage samples containing poliovirus in Israel has led to a countrywide campaign to offer oral polio vaccines to children between the ages of four months and nine years, as a precaution. No cases have appeared in Israel. And the numbers of those affected in Somalia and Kenya are small—110 as of August 7—with 177 reported cases worldwide so far this year, according to data from the Global Polio Eradication Initiative. In April the group issued a detailed strategic plan to eliminate polio "for all time" by 2018. Fully funded, the comprehensive vaccination and monitoring and surveillance plan would cost about $5.5 billion. But in the meantime, this highly infectious nerve disease persists, potentially causing lifelong paralysis in the young children it most often targets. Why has the end remained elusive, and what is being done to protect against future setbacks? Polio in Perspective It's important to remember there is no cure for polio; it exists only in humans, and it can only be prevented by vaccination, says Dr. Jay Wenger, director of the polio eradication program at the Bill and Melinda Gates Foundation. Put those factors together and it means that "to eradicate polio we essentially have to vaccinate enough children so that the poliovirus has no place to go," he says. In the United States, effective vaccine campaigns have kept the population polio free since 1979. But as recently as the late 1940s and early 1950s—before the anti-polio vaccines were developed—the disease disabled approximately 35,000 people, many of them children, in the U.S. each year. By contrast, between 1988 and today, the number of polio-endemic countries has gone from 125 to just three, and in 2012 only 223 cases were recorded worldwide. Given that larger picture, "it's important to put the issue of setbacks into the context of the program and recognize that progress continues," says Dr. Hamid Jafari, director of the WHO's Global Polio Eradication Initiative. Or, as Dr. Wenger puts it: "These outbreaks highlight the importance of eliminating the virus" in the remaining endemic countries. Logistics, Logistics, Logistics Vaccines are the answer. The challenge lies in identifying, locating, and then reaching people of all ages who have not yet been vaccinated. For example, highly mobile groups, such as Nigeria's nomadic livestock herders, may spread the disease as they travel from place to place. (According to the WHO, the polio strains affecting residents of the Horn of Africa originated in West Africa.) At the same time, armed conflict, political unrest, and what Dr. Jafari calls "complex geopolitical situations" can make access by vaccine workers at times dangerous or difficult, if not impossible. Such conditions are present in parts of all three countries where polio is endemic, making different pockets or areas insecure for efficient vaccine delivery at different times. Public health infrastructure can also be spotty, if it exists at all. Because each area can present a distinct set of obstacles, detailed and tailored strategies need to be worked out for each situation, including partnerships with local authorities, community groups, traditional leaders, and non-governmental organizations (NGOs), says Dr. Jafari. "Fundamental commitment to the program from the top of the government down to the local authorities" is needed if everyone is to be vaccinated. Resistance, Distrust, and Violence Mistrust of outsiders is another major obstacle, brutally dramatized by the targeted killings of polio vaccine workers in Nigeria and Pakistan over the past year. In Pakistan's North and South Waziristan, the Taliban have banned vaccination since June 2012, leaving children without immunity and at high risk for the disease. Dr. Jafari is stoic, but not despairing. "As long as there are authorities on the ground and mothers who want to protect their children," there is a way to make progress, he says. "That is why, despite the shootings, the people come out with their children to get them vaccinated … and these brave men and women are going out in their communities to vaccinate" the children. Environmental Vigilance Beyond vaccination, surveillance and monitoring the presence of the virus in the environment are essential to eradicating polio. It's not known how the virus was carried to Israel, which detected poliovirus in sewage samples starting in February 2013. According to the WHO, the strain in Israel is related to the South Asian cluster of wild poliovirus currently circulating in Pakistan, which had recently also been detected through environmental sampling in Egypt. The current oral vaccine campaign in Israel—which is polio free and has a very high rate of immunization—is a safeguard, a direct response to the detection of poliovirus in its sewage. The goal of Israel's vaccine campaign is to boost immunity levels even in children who have already received the injected vaccine, as well as to protect against further spread to anyone traveling in or out of Israel. Setbacks on the Radar Against the backdrop of all these issues, the setbacks in Kenya and Somalia show how quickly and far poliovirus can travel, and demonstrate the importance of maintaining high immunity levels within populations and the need for strong surveillance to halt its spread. According to Dr. Jafari, such setbacks will happen "as long as the virus is alive and people are moving with the virus, and it will spread as people move. And when it lands in places where immunization and sanitation are not in place, that is where the setbacks will take place." The key is being prepared to deal with them, while continuing to move forward. "We're on track, and we'll deal with these outbreaks," he says. "They are not obstacles; they are part of the course."
字数[1285] Source: http://news.nationalgeographic.com/news/2013/11/131101-polio-syria-somalia-kenya-pakistan-israel-vaccine/?source=hp_dl4_news-syria-polio_20131105
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