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大家好，胖胖翔能在教师节发帖，真是太幸运了！祝亲爱的老师们节日快乐！今天的内容比较有趣，越障部分的文章挺长，希望大家耐心看完，很有意思！
Part I：Speaker 【Rephrase1】 Article 1 European Men Experienced Century-Plus Growth Spurt
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We already know human populations can get taller over time. But a new study shows just how extreme this growth spurt can be. Economic historian Timothy Hatton, of the University of Essex and Australian National University, examined height changes in a relatively short time period and small geographical region. His data sample consisted of adult males around 21 years old, who were born in 15 European countries between 1856 and 1980. The study is published in Oxford Economic Papers. [Timothy J. Hatton, How Have Europeans Grown So Tall?] Over the century-and-a-third, average height increased by about 11 centimeters, a good half-a-head. But why? According to Hatton, improvements in sanitation and housing reduced infant mortality and childhood diseases. The result was healthier and thus taller children. Other factors included increased wealth, education and social and health programs. Smaller families, which ensured that each child had more to eat, may have played a role as well. In general, a taller population is a marker for better health. So congratulations, Europe—keep living large. Source: http://www.scientificamerican.com/podcast/episode.cfm?id=european-men-experienced-century-pl-13-09-06
Part II：Speed 【Time 2】 Article 2 Richard III, Begnawed by Worms
It's not every day that the body of a king turns up, especially one who died in battle and was buried in haste. But last year, archaeologists discovered the skeleton of King Richard III under a parking lot in Leicester, U.K. Ever since, researchers have been looking for clues about his life. Using a microscope, the scientists found eggs, just 55 microns wide, of the roundworm Ascaris lumbricoides where his intestines would have been in the grave. Adult roundworms grow up to 30 centimeters long, absorb nutrients from the gut, and can produce 200,000 eggs a day for a year. As published today in The Lancet, scientists found only a few eggs anywhere else around the remains or in the surrounding soil so they conclude that the eggs from his gut (see photo inset) came from a roundworm infection, not contamination of the soil. As roundworm eggs hatch, they dig their way through the heart and lungs, so Richard may have spit blood and suffered abdominal pain. It could have been worse: Noblemen like Richard ate a lot of beef, pork, and fish, which carry the other common gut parasite, tapeworms, but cooking prevents infection. Richard apparently had no tapeworms. He probably acquired his roundworms from water or raw food contaminated with feces, a common fertilizer during the Middle Ages.
字数[220] Source: http://news.sciencemag.org/biology/2013/09/scienceshot-richard-iii-begnawed-worms
【Time 3】
Article 3 'Mercenary' Ant Is Both Scourge and Savior
The fungus-farming ants Sericomyrmex amabilis of Central and South America are often plagued by the parasitic Megalomyrmex symmetochus (left), which live among them for years, living off their food and mutilating their virgin queens. But new observations put an odd twist in this parasitic tale. A large population of nonfertile Megalomyrmex workers, whose function had been unclear, patrols their host’s territory to defend against an even more menacing invader: the predatory Gnamptogenys hartmani (right). Scientists staged a series of face-offs among the three ant species in the lab, as they report online today in the Proceedings of the National Academy of Sciences. In Sericomyrmex nests with no parasites, two introduced Gnamptogenys ants obliterated roughly 70% of the colony. But in parasitized nests, the Megalomyrmex ants dispensed an alkaloid venom that not only killed the Gnamptogenys raiders, but also turned them against one another. The scientists compare Megalomyrmex to the mercenaries who protected a medieval city during conflicts but drained its resources in times of peace.
字数[165] Source: http://news.sciencemag.org/plants-animals/2013/09/scienceshot-mercenary-ant-both-scourge-and-savior
【Time 4】 Article 4 Better fathers have smaller testicles Study finds evolutionary trade-off between mating prowess and parenting involvement.
Fathers with smaller testes are more involved in child care, and their brains are also more responsive when looking at photos of their own children, according to research published online today in the Proceedings of the National Academy of Sciences.
Evolutionary biologists have long observed a trade-off in male primates between mating efforts to produce more offspring and the time males spend caring for their progeny. For instance, male chimpanzees, which are especially promiscuous, sport testes that are twice as big as those of humans, make a lot of sperm and generally do not provide paternal care. By contrast, male gorillas have relatively small testes and protect their young. The latest study suggests that humans, whose paternal care varies widely, show evidence of both approaches.
The analysis incorporates measures of testicular volume, brain activity and paternal behaviour, notes Peter Gray, an anthropologist at the University of Nevada, Las Vegas, who was not involved in the study. “We’ve got something that pulls those strands together, and it does so in a really interesting way.”
The research team — led by James Rilling, an anthropologist at Emory University in Atlanta, Georgia — set out to investigate why some fathers are more involved in child care than others.
The researchers recruited 70 fathers of children aged between one and two years, and scanned the men’s brains and testes in a magnetic resonance imaging (MRI) machine. The fathers and the children's mothers also filled out surveys rating the fathers' commitment to child care.
字数[257]
【Time 5】
Proud parents
When men were shown photos of their own children, those rated as better fathers by their female partners had more activity in the ventral tegmental area (VTA) of the brain, part of its reward system. Men with larger testes were rated lower in surveys of their parenting involvement and had less activity in the VTA. Because testes size is correlated with sperm count, Rilling and his team took the size as a measure of mating effort.
The researchers also analysed the men’s testosterone levels, confirming a previous finding that fathers involved in caring for their children have lower levels of the hormone.
“It’s a very provocative and important step,” says Sarah Hrdy, an emeritus anthropologist at the University of California, Davis. She adds that more research is needed to establish whether certain men are predisposed by biology to be more nurturing. The study’s authors say that even if men are predisposed to a certain style of parenting, nurturing dads can be made as well as born. That levels of testosterone changed as a father spent more time with his child suggest flexibility in a man's inclination toward fatherhood.
Charles Snowdon, a psychologist at the University of Wisconsin-Madison, points out that the paper’s own statistics show testes size explains only a fraction of the variation in paternal care. “There are lots of other variables that affect fatherhood,” he says, citing as examples social environment and prior experience looking after younger siblings when the men were children themselves.
Rilling and his team plan to test how testicular size is affected by factors such as genetics or the man having an absent father. They were surprised to find little research on how testes size changes in response to life events. “Testicular imaging is sort of a unique niche right now,” says Rilling.
字数[302] Source: http://www.nature.com/news/better-fathers-have-smaller-testicles-1.13701
【Time 6】 Article 5 Radio telescope images reveal nebula's heart of carbon ALMA takes detailed look at elements surrounding dying star
New high-resolution images of a planetary nebula show carbon atoms concentrated in a small region near its center. The images are the most detailed radio telescope observations to date of atoms swirling about a dying star.
Made of a star once five times the mass of the sun, planetary nebula NGC 6302 sits about 3,800 light-years from Earth in the constellation Scorpius. Scientists are interested in getting a close-up of its carbon, hydrogen and oxygen to understand the chemical environment in and around dying stars.
Combining submillimeter-wavelength observations with images taken using the Hubble Space Telescope, astronomers were able to identify the location of the carbon atoms. Astronomers zoomed in on the planetary nebula using five 7-meter radio antennas at the Atacama Large Millimeter/submillimeter Array, or ALMA, in northern Chile.
Future observations with additional ALMA’s antennas could provide a view that’s 400 times the resolution of these images. And, since reactions between carbon and other atoms, such as oxygen and hydrogen, create complex molecules necessary for planets and life, astronomers say the view could explain more about the evolution of the universe.
字数[191]
Source: http://www.sciencenews.org/view/generic/id/352976/description/Radio_telescope_images_reveal_nebulas_heart_of_carbon
Part III： Obstacle
【Paraphase7】
Article 6 Earth science: How plate tectonics clicked Fifty years after a paper linked sea-floor magnetic stripes with continental drift, Naomi Oreskes explains its legacy as a lesson in achieving scientific consensus.
By the time German geophysicist Alfred Wegener proposed continental drift in 1912, palaeontologists had long accepted that past connections between now-separate lands explained the spread of similar fossils and rock layers across them. Geologists, too, knew of slabs of Alpine rock that had been displaced hundreds of kilometres during mountain building.
But the arguments for continental motions did not gel until the 1960s, when a drastic expansion of geophysical research, driven by the cold war, produced evidence that reopened and eventually settled the debate.
One influential study was published in Nature 50 years ago this week. British geologists Frederick Vine and Drummond Matthews interpreted stripes of alternating magnetic-field polarity in ocean bedrock as evidence of a spreading sea floor that pushed continents apart. Acceptance that large crustal motions were a reality soon followed, culminating in the theory of plate tectonics.
In its slow convergence of ideas and evidence, the history of plate tectonics holds lessons for today's debates about human-induced climate change. Although science is always evolving, and our attention is drawn to controversy at the research frontier, it is the stable core of 'consensus' knowledge that provides the best basis for decision-making.
Mantle convection Wegener stands out because his solution was close to the one that we now accept, and because our individualist culture encourages us to look for heroes to credit and discrete events to celebrate. But he was not alone in trying to explain commonalities in fossils and rock strata. In the English-speaking world, two of the most important players in developing theories of continental-scale crustal mobility were South African field geologist Alexander du Toit and British geochronologist Arthur Holmes.
Du Toit articulated the case in his aptly named 1937 book Our Wandering Continents (Oliver and Boyd). He acted as a clearing house for geologists around the globe, who sent him maps, rocks and fossils. Holmes, working with the Irish geochemist John Joly, suggested that crustal motion was driven by radioactivity and the heat that it emanates, advocating mantle convection as a means of dissipating radiogenic heat and driving continental drift. Holmes's 1944 textbook Principles of Physical Geology (Thomas Nelson & Sons) was an introduction to the subject for many students.
The discussion was joined by Dutch geodesist Felix Vening Meinesz, who worked in the 1930s in the Indonesian archipelago and, with US geologists Harry Hess and Maurice Ewing, in the Caribbean. Meinesz found that Earth's gravitational field was weaker than normal above some of the ocean's deepest regions, which he explained in terms of the buckling of low-density crust into the mantle, dragged down by descending convection currents, and he discussed these ideas with Hess.
During the Second World War, Hess found himself in the US Navy, fighting in the Pacific theatre. He did not return immediately to tectonics after the war, but others did, including several British geophysicists led by P. M. S. Blackett and Keith Runcorn. In an effort to understand the origins of Earth's magnetic field, they discovered that magnetic minerals pointed in different directions at different times in geological history, as if the positions of the poles had changed. Hess was drawn back to the topic after realizing that these 'apparent polar-wandering paths' could be explained by the movements of the continents.
Ocean spreading Hess suggested that rising mantle-convection cells would drive apart the ocean floor above them, increasing the separation of continents to either side. The idea, which his colleague Robert Dietz christened 'sea-floor spreading', explained the old geological observations and the new geophysical ones, but it did not gain immediate traction. That would take further geomagnetic information.
Blackett, a socialist who opposed nuclear proliferation, turned to geomagnetism after the war to distance himself from military work. But military concerns — particularly the demands of submarine warfare in the atomic age — drove geophysical exploration of the ocean floor, leading to the discovery in the late 1950s of sea-floor magnetic stripes.
The stripes were a surprise. In the report of the discovery, oceanographers Ronald Mason and Arthur Raff admitted to being at a loss for an explanation. Others were less stymied. Vine and Matthews, as well as Canadian geophysicist Lawrence Morley, independently had the same idea. If the sea floor was spreading, then magnetic stripes would be expected: rock formed at mid-ocean ridges would take on Earth's magnetic field, the polarity alternating as the field periodically reversed.
It was one thing to say that the oceans were widening, another to link it to global crustal motion. More than two dozen scientists, including women such as Tanya Atwater and Marie Tharp, did the key work that created the theory of plate tectonics as we know it — explaining continental drift, volcanism, seismicity and heat flow around the globe.
In 1965, Canadian geologist Tuzo Wilson proposed a type of 'transform' fault to accommodate the spreading sea floor around mid-ocean ridges, which was confirmed by US seismologist Lynn Sykes. Other seismologists demonstrated that in deep-ocean trenches, slabs of crust were indeed being driven into the mantle, and geophysicists worked out how these crustal 'plates' move and relate to the features of continental geology.
Vine and Matthews' work is part of a larger story of the growth of Earth science in the twentieth century, made possible by improved technology and greater governmental support after the Second World War. Nearly all seismic and marine geophysical data at the time were collected with military backing, in part because of their cold-war security significance.
This era marked a change in the character of modern science. Research today is expensive and largely government-funded; almost all major scientific accomplishments are the collective achievement of large teams. This reality — more prosaic than the hagiography of lonely genius — reminds us that although great individuals are worthy of recognition, the strength and power of science lies in the collective effort and judgement of the scientific community.
Consensus matters In recent months, several of my colleagues in climate science have asked me whether the story of plate tectonics holds lessons for their field in responding to those who disparage the scientific evidence of anthropogenic climate change. I believe that it does.
Many critics of climate science argue that expert agreement is irrelevant. Science, they claim, advances through bold individuals such as Wegener or Galileo Galilei overturning the status quo. But, contrary to the mythology, even Isaac Newton, Charles Darwin and Albert Einstein worked within scientific communities, and saw their work accepted. In glorifying the lone genius, climate-change dissenters tap into a rich cultural vein, but they miss what consensus in science really is and why it matters.
Consensus emerges as scientific knowledge matures and stabilizes. With some notable exceptions, scientists do not consciously try to achieve consensus. They work to develop plausible hypotheses and collect pertinent data, which are debated at conferences, at workshops and in peer-reviewed literature. If experts judge the evidence to be sufficient, and its explanation coherent, they may consider the matter settled. If not, they keep working. History enables us to judge whether scientific claims are still in flux and likely to change, or are stable, and provide a reasonable basis for action.
And maturity takes time. Scientific work, compared with industry, government or business, has no deadline. Perhaps for this reason, when Wegener died in 1930, according to his biographers he was confident that other scientists would one day work out how the continents moved, and that this mechanism would be along the lines of his proposal — as indeed it was. Du Toit and Holmes were similarly convinced.
The equanimity of these men speaks to their confidence in science as a system. They perceived what historian–philosopher Thomas Kuhn articulated in The Structure of Scientific Revolutions (University of Chicago Press, 1962): that science is a community affair and that knowledge emerges as the community as a whole accepts it. A debate comes to a close once scientists are persuaded that a phenomenon is real and that they have settled on the right explanation. Further discussion is not productive unless new evidence emerges, as it did for continental drift. Anthropogenic climate change has the consensus of researchers. Political leaders who deny the human role in climate change should be compared with the hierarchy of the Catholic church, who dismissed Galileo's arguments for heliocentrism for fear of their social implications. But what of scientists who in good faith reject the mainstream view?
Harold Jeffreys is an intriguing example. An eminent professor of astronomy at the University of Cambridge, UK, Jeffreys rejected continental drift in the 1920s and plate tectonics in the 1970s. He believed that the solid Earth was too rigid to permit mantle convection and crustal motion. His view had a strong mathematical basis, but it remained unchanged, even as evidence to the contrary mounted.
If society had faced a major decision in the 1970s that hinged on whether or not continents moved, it would have been foolish to heed Jeffreys and to ignore the larger consensus, backed by half a century of research. As an early advocate of an immature theory, Wegener was different. There were substantial differences of opinion about crustal mobility among scientists in the 1920s. By the 1970s, work such as Vine and Matthews' study had brought consensus.
Fifty years on, history has not vindicated Jeffreys, and it seems unlikely that it will vindicate those who reject the overwhelming evidence of anthropogenic climate change.
字数[1579] Source: http://www.nature.com/news/earth-science-how-plate-tectonics-clicked-1.13655
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