some time ago scientists began experiments

Some time ago, scientists began experiments to find out (31)______ it would be possible to set up a "village" under the sea. A special room was built and lowered (32)______ the water of Port Sudan in the Red Sea. For 29 days, five men lived (33)______ a depth of 40 feet. The science: Baking soda is a base, tartaric acid is, of course, an acid. When the two combine, carbon dioxide gas is quickly created. This gas is much less dense than the powders it came from But the road to understanding climate change stretches back to the tweed-clad middle years of the 19th century—when Victorian-era scientists conducted the first experiments proving that runaway CO2 could, one day, cook the planet. In other words, " global warming was officially discovered more than 100 years ago ." * * * A little over 2,000 years ago, the story of the historical Jesus of Nazareth, son of a carpenter and stone mason, begins in a tiny village in the hills of the Galilee. Some 30 years later, in. give some last days timeline but discovers that the people are mentally unprepared so he takes a break and then gets back into it in chapter 20. Some time ago, scientists began experiments to find out (1)______ it would be possible to set up a "village" under the sea. A special room was built and lowered (2)______ the water of Port Sudan in the Red Sea. For 29 days, five men lived at a depth of 40 feet. At a (3)______ lower level, another two divers stayed for a week in a smaller "house". Frühstückstreffen Für Frauen In Deutschland Ev. A fossil collector since childhood, Bob Hazen has come up with new scenarios for life's beginnings on earth billions of years ago. Amanda Lucidon A hilly green campus in Washington, houses two departments of the Carnegie Institution for Science the Geophysical Laboratory and the quaintly named Department of Terrestrial Magnetism. When the institution was founded, in 1902, measuring the earth’s magnetic field was a pressing scientific need for makers of nautical maps. Now, the people who work here—people like Bob Hazen—have more fundamental concerns. Hazen and his colleagues are using the institution’s “pressure bombs”—breadbox-size metal cylinders that squeeze and heat minerals to the insanely high temperatures and pressures found inside the earth—to decipher nothing less than the origins of life. Hazen, a mineralogist, is investigating how the first organic chemicals—the kind found in living things—formed and then found each other nearly four billion years ago. He began this research in 1996, about two decades after scientists discovered hydrothermal vents—cracks in the deep ocean floor where water is heated to hundreds of degrees Fahrenheit by molten rock. The vents fuel strange underwater ecosystems inhabited by giant worms, blind shrimp and sulfur-eating bacteria. Hazen and his colleagues believed the complex, high-pressure vent environment—with rich mineral deposits and fissures spewing hot water into cold—might be where life began. Hazen realized he could use the pressure bomb to test this theory. The device technically known as an “internally heated, gas media pressure vessel” is like a super-high-powered kitchen pressure cooker, producing temperatures exceeding 1,800 degrees and pressures up to 10,000 times that of the atmosphere at sea level. If something were to go wrong, the ensuing explosion could take out a good part of the lab building; the operator runs the pressure bomb from behind an armored barrier. In his first experiment with the device, Hazen encased a few milligrams of water, an organic chemical called pyruvate and a powder that produces carbon dioxide all in a tiny capsule made of gold which does not react with the chemicals inside that he had welded himself. He put three capsules into the pressure bomb at 480 degrees and 2,000 atmospheres. And then he went to lunch. When he took the capsules out two hours later, the contents had turned into tens of thousands of different compounds. In later experiments, he combined nitrogen, ammonia and other molecules plausibly present on the early earth. In these experiments, Hazen and his colleagues created all sorts of organic molecules, including amino acids and sugars—the stuff of life. Hazen’s experiments marked a turning point. Before them, origins-of-life research had been guided by a scenario scripted in 1871 by Charles Darwin himself “But if and oh! what a big if! we could conceive in some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, etc., present, that a proteine compound was chemically formed ready to undergo still more complex changes....” In 1952, Stanley Miller, a graduate student in chemistry at the University of Chicago, attempted to create Darwin’s dream. Miller set up a container holding water representing the early ocean connected by glass tubes to one containing ammonia, methane and hydrogen—a mixture scientists of the day thought approximated the early atmosphere. A flame heated the water, sending vapor upward. In the atmosphere flask, electric sparks simulated lightning. The experiment was such a long shot that Miller’s adviser, Harold Urey, thought it a waste of time. But over the next few days, the water turned deep red. Miller had created a broth of amino acids. Forty-four years later, Bob Hazen’s pressure bomb experiments would show that not just lightning storms but also hydrothermal vents potentially could have sparked life. His work soon led him to a more surprising conclusion the basic molecules of life, it turns out, are able to form in all sorts of places near hydrothermal vents, volcanoes, even on meteorites. Cracking open space rocks, astrobiologists have discovered amino acids, compounds similar to sugars and fatty acids, and nucleobases found in RNA and DNA. So it’s even possible that some of the first building blocks of life on earth came from outer space. Hazen’s findings came at an auspicious time. “A few years before, we would have been laughed out of the origins-of-life community,” he says. But NASA, then starting up its astrobiology program, was looking for evidence that life could have evolved in odd environments—such as on other planets or their moons. “NASA [wanted] justification for going to Europa, to Titan, to Ganymede, to Callisto, to Mars,” says Hazen. If life does exist there, it’s likely to be under the surface, in warm, high-pressure environments. Back on earth, Hazen says that by 2000 he had concluded that “making the basic building blocks of life is easy.” A harder question How did the right building blocks get incorporated? Amino acids come in multiple forms, but only some are used by living things to form proteins. How did they find each other? In a windowed corner of a lab building at the Carnegie Institution, Hazen is drawing molecules on a notepad and sketching the earliest steps on the road to life. “We’ve got a prebiotic ocean and down in the ocean floor, you’ve got rocks,” he says. “And basically there’s molecules here that are floating around in solution, but it’s a very dilute soup.” For a newly formed amino acid in the early ocean, it must have been a lonely life indeed. The familiar phrase “primordial soup” sounds rich and thick, but it was no beef stew. It was probably just a few molecules here and there in a vast ocean. “So the chances of a molecule over here bumping into this one, and then actually a chemical reaction going on to form some kind of larger structure, is just infinitesimally small,” Hazen continues. He thinks that rocks—whether the ore deposits that pile up around hydrothermal vents or those that line a tide pool on the surface—may have been the matchmakers that helped lonely amino acids find each other. Rocks have texture, whether shiny and smooth or craggy and rough. Molecules on the surface of minerals have texture, too. Hydrogen atoms wander on and off a mineral’s surface, while electrons react with various molecules in the vicinity. An amino acid that drifts near a mineral could be attracted to its surface. Bits of amino acids might form a bond; form enough bonds and you’ve got a protein. Back at the Carnegie lab, Hazen’s colleagues are looking into the first step in that courtship Kateryna Klochko is preparing an experiment that—when combined with other experiments and a lot of math—should show how certain molecules stick to minerals. Do they adhere tightly to the mineral, or does a molecule attach in just one place, leaving the rest of it mobile and thereby increasing the chances it will link up to other molecules? Klochko gets out a rack, plastic tubes and the liquids she needs. “It’s going to be very boring and tedious,” she warns. She puts a tiny dab of a powdered mineral in a four-inch plastic tube, then adds arginine, an amino acid, and a liquid to adjust the acidity. Then, while a gas bubbles through the solution, she waits...for eight minutes. The work may seem tedious indeed, but it takes concentration. “That’s the thing, each step is critical,” she says. “Each of them, if you make a mistake, the data will look weird, but you won’t know where you made a mistake.” She mixes the ingredients seven times, in seven tubes. As she works, “The Scientist” comes on the radio “Nooooobody saaaaid it was easyyyy,” sings Coldplay vocalist Chris Martin. After two hours, the samples go into a rotator, a kind of fast Ferris wheel for test tubes, to mix all night. In the morning, Klochko will measure how much arginine remains in the liquid; the rest of the amino acid will have stuck to the mineral powder’s tiny surfaces. She and other researchers will repeat the same experiment with different minerals and different molecules, over and over in various combinations. The goal is for Hazen and his colleagues to be able to predict more complex interactions, like those that may have taken place in the earth’s early oceans. How long will it take to go from studying how molecules interact with minerals to understanding how life began? No one knows. For one thing, scientists have never settled on a definition of life. Everyone has a general idea of what it is and that self-replication and passing information from generation to generation are key. Gerald Joyce, of the Scripps Research Institute in La Jolla, California, jokes that the definition should be “something like that which is squishy.’” Hazen’s work has implications beyond the origins of life. “Amino-acids-sticking-to-crystals is everywhere in the environment,” he says. Amino acids in your body stick to titanium joints; films of bacteria grow inside pipes; everywhere proteins and minerals meet, amino acids are interacting with crystals. “It’s every rock, it’s every soil, it’s the walls of the building, it’s microbes that interact with your teeth and bones, it’s everywhere,” Hazen says. At his weekend retreat overlooking the Chesapeake Bay, Hazen, 61, peers through binoculars at some black-and-white ducks bobbing around in circles and stirring the otherwise still water. He thinks they’re herding fish—a behavior he’s never seen before. He calls for his wife, Margee, to come take a look “There’s this really interesting phenomenon going on with the buffleheads!” Living room shelves hold things the couple has found nearby beach glass, a basketful of minerals, and fossilized barnacles, coral and great white shark teeth. A 15-million-year-old whale jawbone, discovered on the beach at low tide, is spread out in pieces on the dining room table, where Hazen is cleaning it. “It was part of a living, breathing whale when this was a tropical paradise,” he says. Hazen traces his interest in prehistory to his Cleveland childhood, growing up not far from a fossil quarry. “I collected my first trilobite when I was 9 or 10,” he says. “I just thought they were cool,” he says of the marine arthropods that went extinct millions of years ago. After his family moved to New Jersey, his eighth-grade science teacher encouraged him to check out the minerals in nearby towns. “He gave me maps and he gave me directions and he gave me specimens, and my parents would take me to these places,” says Hazen. “So I just got hooked.” After taking a paleontology class together at the Massachusetts Institute of Technology, Hazen and Margee Hindle, his future wife, started collecting trilobites. They now have thousands. “Some of them are incredibly cute,” says Hazen. “This bulbous nose—you want to hug them.” There are trilobites all over Hazen’s office and a basement guest room at the Hazens’ Bethesda, Maryland, home—they cover shelves and fill desk drawers and cabinets. There’s even trilobite art by his now grown children, Ben, 34, who is studying to be an art therapist, and Liz, 32, a teacher. “This is the ultimate cute trilobite,” he says, reaching into a cabinet and taking out a Paralejurus. “How can you not love that?” Hazen calls himself a “natural collector.” After he and Margee bought a picture frame that just happened to hold a photograph of a brass band, they started buying other pictures of brass bands; eventually they wrote a history of brass bands—Music Men—and a time in America when almost every town had its own. Bob has played trumpet professionally since 1966. He has also published a collection of 18th-and 19th-century poems about geology, most of which, he says, are pretty bad “And O ye rocks! schist, gneiss, whate’er ye be/Ye varied strata, names too hard for me”. But the couple tend not to hold on to things. “As weird as this sounds, as a collector, I’ve never been acquisitive,” Bob says. “To have been able to hold them and study them up close is really a privilege. But they shouldn’t be in private hands.” Which is why the Hazen Collection of Band Photographs and Ephemera, ca. 1818-1931, is now at the National Museum of American History. Harvard has the mineral collection he started in eighth grade, and the Hazens are in the process of donating their trilobites to the National Museum of Natural History. After considering, for some time, how minerals may have helped life evolve, Hazen is now investigating the other side of the equation how life spurred the development of minerals. He explains that there were only about a dozen different minerals—including diamonds and graphite—in dust grains that pre-date the solar system. Another 50 or so formed as the sun ignited. On earth, volcanoes emitted basalt, and plate tectonics made ores of copper, lead and zinc. “The minerals become players in this sort of epic story of exploding stars and planetary formation and the triggering of plate tectonics,” he says. “And then life plays a key role.” By introducing oxygen into the atmosphere, photosynthesis made possible new kinds of minerals—turquoise, azurite and malachite, for example. Mosses and algae climbed onto land, breaking down rock and making clay, which made bigger plants possible, which made deeper soil, and so on. Today there are about 4,400 known minerals—more than two-thirds of which came into being only because of the way life changed the planet. Some of them were created exclusively by living organisms. Everywhere he looks, Hazen says, he sees the same fascinating process increasing complexity. “You see the same phenomena over and over, in languages and in material culture—in life itself. Stuff gets more complicated.” It’s the complexity of the hydrothermal vent environment—gushing hot water mixing with cold water near rocks, and ore deposits providing hard surfaces where newly formed amino acids could congregate—that makes it such a good candidate as a cradle of life. “Organic chemists have long used test tubes,” he says, “but the origin of life uses rocks, it uses water, it uses atmosphere. Once life gets a foothold, the fact that the environment is so variable is what drives evolution.” Minerals evolve, life arises and diversifies, and along come trilobites, whales, primates and, before you know it, brass bands. Helen Fields has written about snakehead fish and the discovery of soft tissue in dinosaur fossils for Smithsonian. Amanda Lucidon is based in Washington, / To mimic conditions for life on early earth, Bob Hazen, in his Carnegie lab, used a "pressure bomb" to heat and compress chemicals. Amanda Lucidon / A fossil collector since childhood, Hazen, shown here inspecting ancient seashells on Chesapeake Bay, has come up with new scenarios for life's beginnings on earth billions of years ago. Amanda Lucidon / Scientists are searching for life's origins beyond the "warm little pond" that, 140 years ago, Charles Darwin speculated was the starting place. Kateryna Klochko, in Hazen's lab, combines mineral dust and amino acids, the building blocks of proteins. Amanda Lucidon / Some meteorites, shown here is a magnified cross section of one found in Chile, contain amino acids, raising the possibility that life was seeded from space. Amanda Lucidon / Despite high temperatures and pressures, deep-sea hydrothermal vents harbor living things. Science Source / Hazen began collecting trilobites—extinct marine arthropods like this Paralejurus—when he was a child. Amanda Lucidon / The first organic molecules may have needed rocks to bring them together, says Hazen, with his wife Margee near their Chesapeake Bay weekend retreat. But the relationship goes both ways once living things were established, they created new minerals. Amanda Lucidon Get the latest Science stories in your inbox. Recommended Videos Filed Under Earth Science William Beal, standing at center, started a long-term study on seed germination in 1879. He buried 20 bottles with seeds in them for later researchers to unearth and plant. Michigan State University hide caption toggle caption Michigan State University William Beal, standing at center, started a long-term study on seed germination in 1879. He buried 20 bottles with seeds in them for later researchers to unearth and plant. Michigan State University A biologist who has been watching a dozen bottles of bacteria evolve for nearly a quarter of a century is hoping he can find someone to keep his lab experiment going long after he dies. Meanwhile, just by coincidence, a botanist who works across campus is carefully tending an experiment that started before he was born, all the way back in 1879. These two researchers, both at Michigan State University in East Lansing, represent different sides of an unusual phenomenon in science experiments that outlive the people who started them. Most researchers design studies to churn out results as quickly as possible. But because nature can work on vast time scales, some questions can take longer to answer than any one scientist's career. Richard Lenski began his evolution experiment in 1988 with a simple question Does evolution always lead to the same end point? If he started with 12 identical flasks, full of identical bacteria, would they all change over time in the same way? Or would random mutations send each bottle's population spinning off in a different direction? Richard Lenski examines the growth of bacteria on a plate on Jan. 12. He began an evolution experiment in 1988 with 12 identical flasks of bacteria to see if the populations would change over time in the same way. Kohuth/Michigan State University hide caption toggle caption Kohuth/Michigan State University Richard Lenski examines the growth of bacteria on a plate on Jan. 12. He began an evolution experiment in 1988 with 12 identical flasks of bacteria to see if the populations would change over time in the same way. Kohuth/Michigan State University "This was an experiment that was intended to be a long-term experiment, although I had no idea that it would be multiple decades," says Lenski, an evolutionary biologist. "It does just keep producing new and interesting results, so it doesn't seem to be near the end of its life span." Every day, someone in his lab has to do the brief, tedious chore of feeding and caring for the bacteria. On day number 8,449, Lenski reached into an incubator and pulled out his old friends. These E. coli bacteria reproduce so rapidly that, in one day, they speed through seven generations — creating the equivalent of their great-great-great-great grandchildren and letting Lenski watch their evolution in real time. Lenski brought the flasks over to a lab bench and reached for his glasses. "When I started this experiment, I didn't need reading glasses," he notes, "and now looking at things close-up is always more work than it used to be." For the first decade of his experiment, the bacteria in each flask mostly changed in similar ways. For example, they all were producing larger cells. Then things got kind of boring for a while because the changes started coming more slowly. Lenski had other projects going on in his lab, and figured that maybe he'd learned all he could from this one. "And so I was sort of thinking, 'OK, maybe it's time to stop the experiment,' " he says, recalling that he asked a few colleagues what they thought of that idea. "And they basically said, 'Nope, you can't stop it, it's gone on too long.' " So he stuck with it. And a few years later, in 2003, something happened. The liquid in one flask looked strange. "This flask was considerably more cloudy," says Lenski. "I was suspicious that we had a contaminant." It turns out that the bacteria in that one flask had actually changed in a dramatic way. After 30,000 generations, they had suddenly gained the ability to consume citrate, a chemical that had always been in the flasks — but that was never intended to be a food, since laboratory E. coli normally can't eat it. What's more, Lenski was able to trace exactly how that new trait emerged. Over the years, he's been freezing samples of his bacteria, so he was able to go back and track every little genetic change that's taken place through the generations, using technologies that didn't even exist when he first started this study. Lenski is now convinced that this study should keep going far into the future, to see what else might evolve. He'd like to see this experiment go on not just for 50,000 bacterial generations but 50,000 human generations, to "really get some very hard numbers on the process of evolution." The fact that Lenski won't be around to see those hard numbers doesn't seem to bother him. "My wife and I were very fortunate that one of our daughters had a baby about 20 months ago. And that really changes one's perception of time even more than a long-term experiment," Lenski says. He notes that people tend to conflate the universe with their own existence, "but having children, grandchildren and so on ... you really just come to grips with the vast span of time that is available. And we only get to occupy a tiny portion of it." Lenski, who is 56 years old, thinks he'll watch his bacteria for about another decade. Then he'll have to find someone to inherit this project. It's not a particularly expensive or difficult study — so he just needs to find someone younger who has a lab and is willing to carry his vision forward. "They might be in their, you know, early- or mid-30s or something like that," Lenski says, "and then they can decide whether they want to do it for just the next five or 10 years or whether they want to continue it for another 30 years and perhaps pass it on to somebody who hasn't even been born yet." Is it really possible to keep an experiment going like that? The answer is undoubtedly yes, as Lenski learned years ago when he heard of another long-term study happening on campus. "Here I was, proud of myself for what was at that time maybe a 15-year experiment, discovering that it wasn't even the oldest experiment on campus — that there was another one up around 100 years, or even past that," recalls Lenski. Seeds Buried Long, Long Ago That experiment is currently cared for by Frank Telewski, who runs Michigan State University's botanical garden. The garden is named after botanist William J. Beal, and he started a long-term study on seed germination all the way back in 1879. Beal was inspired by local farmers who had been asking him this question If we weed our fields year after year, will we ever reach a point where the weeds just don't come back? "Well, that was a very interesting question," says Telewski, because it wasn't at all clear how long seeds might remain viable in the soil. "We know that seeds can remain dormant for a long period of time, and Professor Beal's key question was, 'How long?' " Bottles like this 90-year-old one were filled with seeds and sand, then buried by William Beal. Researchers periodically unearth a bottle and plant the seeds to see if they grow. Kurt Stepnitz/Michigan State University hide caption toggle caption Kurt Stepnitz/Michigan State University Bottles like this 90-year-old one were filled with seeds and sand, then buried by William Beal. Researchers periodically unearth a bottle and plant the seeds to see if they grow. Kurt Stepnitz/Michigan State University So Beal put a precise quantity of seeds from different species into 20 sand-filled bottles and stashed them underground. The original plan was to dig up one bottle every five years and see what would grow. "Clearly, burying 20 bottles and only taking one out every five years, the plan was to go beyond Professor Beal's career, let alone Professor Beal's life," says Telewski. The only writings from Beal about his experiment are dry scientific reports, but Telewski assumes it meant a lot to him. "He had to be passionate about it," says Telewski. "You don't do something like this, you know, with that long-term desire, without being passionate." Beal opened six bottles before he retired. Then he passed it on to a colleague, Henry Darlington. Eventually it was taken over by others, including Robert Bandurski and Jan Zeevaart, who passed it on to Telewski. The experiment has lasted longer than Beal ever intended because the caretakers extended it. They first decided to open a bottle only once every decade, and now, once every two decades. Telewski dug up his first bottle 12 years ago. He did it at night, with a flashlight, trying not to draw any attention to the secret burial spot. He says it was exciting to think back and remember that the last person to see the seed was Beal, 120 years ago. "For me that holds a level of significance, that holds a level of fascination, charm," says Telewski. And he says the mysteries of long-term seed viability remain scientifically interesting. Only two plant species sprouted from the last Beal bottle. Telewski can't wait to dig up the next bottle, in 2020. Will that be the year that nothing germinates, wonders Telewski, or "will something that hasn't germinated in 30, 40 years all of a sudden appear?" This kind of inherited experiment is unusual, says Telewski, but in another way, the whole of science is one big long-term effort. Every time researchers record a careful observation, or stash a specimen in a museum, they make it possible for some unknown person of the future to pick up where they left off. "And isn't that wonderful that somebody, somewhere, thought forward enough to say, 'Let's hold onto this, let's keep this experiment going, let's design this experiment to go on and see where it takes us,' " says Telewski. Telewski already has someone in mind to inherit the Beal study when he retires. "There's one particular person I've been speaking with, and I think she's going to be very excited to pick it up," he says. If all goes as planned, he thinks the experiment will probably outlive her, too. Some research studies don't yield quick results, and scientists design experiments that continue for years, if not decades. Below is a sampling of some long-term projects, many of which continue to this day. Mouse over the bars for more information about each study. Some time ago, scientists began experiments to find out …………. it would be possible to set up a "village" under the sea. A special room was built and lowered into the water of Port Sudan in the Red Sea. For 29 days, five men lived at a depth of 40 feet. At a .......2….... lower level, another two divers stayed for a week in a smaller "house". On returning to the surface, the men said that they had experienced no difficulty in breathing and had made many interesting scientific observations. The captain of the party, Commander Cousteau, spoke of the possibility of cultivating the seabed. He said that some permanent stations were to be ….……. under the sea, and some undersea farms would provide food for the growing population of the nhật ngày 28-11-2022Chia sẻ bởi Ly a longSome time ago, scientists began experiments to find out …………. it would be possible to set up a "village" under the sea. A special room was built and lowered into the water of Port Sudan in the Red Sea. For 29 days, five men lived at a depth of 40 feet. At a .......2….... lower level, another two divers stayed for a week in a smaller "house". On returning to the surface, the men said that they had experienced no difficulty in breathing and had made many interesting scientific observations. The captain of the party, Commander Cousteau, spoke of the possibility of cultivating the seabed. He said that some permanent stations were to be ….……. under the sea, and some undersea farms would provide food for the growing population of the đề liên quanSome time ago, scientists began experiments to find out …………. it would be possible to set up a "village" under the sea. A special room was built and lowered into the water of Port Sudan in the Red Sea. For 29 days, five men lived at a depth of 40 feet. At a ........... lower level, another two divers stayed for a week in a smaller "house". On returning to the surface, the men said that they had experienced no difficulty in breathing and had made many interesting scientific observations. The captain of the party, Commander Cousteau, spoke of the possibility of cultivating the seabed. He said that some permanent stations were to be ….…3…. under the sea, and some undersea farms would provide food for the growing population of the life in the countryside which is often considered to be simple and traditional, life in the city is modern and complicated. People, from different regions, move to the cities in the hope of having a better life for them and their children. The inhabitants in city work as secretaries, businessmen, teachers, government workers, factory workers and even street vendors or construction workers. The high cost of living requires city dwellers, especially someone with low income, to work harder or to take a part-time job. For many people, an ordinary day starts as usual by getting up in the early morning to do exercise in public parks, preparing for a full day of working and studying, then travelling along crowed boulevards or narrow streets filled with motor scooters and returning home after a busy day. They usually live in large houses, or high-rise apartment blocks or even in a small rental room equipped with modern facilities, like the Internet, telephone, television, and so on. Industrialization and modernization as well as global integration have big impact on lifestyle in the cities. The most noticeable impact is the Western style of clothes. The "Ao dai” - Vietnamese traditional clothes are no longer regularly worn in Vietnamese women's daily life. Instead, jeans, T-shirts and fashionable clothes are widely most important reason why people move to the city is that ………….A to look for a better life B to look for a complicated life Unlike life in the countryside which is often considered to be simple and traditional, life in the city is modern and complicated. People, from different regions, move to the cities in the hope of having a better life for them and their children. The inhabitants in city work as secretaries, businessmen, teachers, government workers, factory workers and even street vendors or construction workers. The high cost of living requires city dwellers, especially someone with low income, to work harder or to take a part-time job. For many people, an ordinary day starts as usual by getting up in the early morning to do exercise in public parks, preparing for a full day of working and studying, then travelling along crowed boulevards or narrow streets filled with motor scooters and returning home after a busy day. They usually live in large houses, or high-rise apartment blocks or even in a small rental room equipped with modern facilities, like the Internet, telephone, television, and so on. Industrialization and modernization as well as global integration have big impact on lifestyle in the cities. The most noticeable impact is the Western style of clothes. The "Ao dai” - Vietnamese traditional clothes are no longer regularly worn in Vietnamese women's daily life. Instead, jeans, T-shirts and fashionable clothes are widely to the passage, the city life can offer city dwellers all of the following things EXCEPT A friendly communication with neighbours C a variety of jobs in different fields Unlike life in the countryside which is often considered to be simple and traditional, life in the city is modern and complicated. People, from different regions, move to the cities in the hope of having a better life for them and their children. The inhabitants in city work as secretaries, businessmen, teachers, government workers, factory workers and even street vendors or construction workers. The high cost of living requires city dwellers, especially someone with low income, to work harder or to take a part-time job. For many people, an ordinary day starts as usual by getting up in the early morning to do exercise in public parks, preparing for a full day of working and studying, then travelling along crowed boulevards or narrow streets filled with motor scooters and returning home after a busy day. They usually live in large houses, or high-rise apartment blocks or even in a small rental room equipped with modern facilities, like the Internet, telephone, television, and so on. Industrialization and modernization as well as global integration have big impact on lifestyle in the cities. The most noticeable impact is the Western style of clothes. The "Ao dai” - Vietnamese traditional clothes are no longer regularly worn in Vietnamese women's daily life. Instead, jeans, T-shirts and fashionable clothes are widely is the main idea of the passage?B people do morning exercise in public parks because they have much free people leave the countryside because life there is most of the urban dwellers have low income. Unlike life in the countryside which is often considered to be simple and traditional, life in the city is modern and complicated. People, from different regions, move to the cities in the hope of having a better life for them and their children. The inhabitants in city work as secretaries, businessmen, teachers, government workers, factory workers and even street vendors or construction workers. The high cost of living requires city dwellers, especially someone with low income, to work harder or to take a part-time job. For many people, an ordinary day starts as usual by getting up in the early morning to do exercise in public parks, preparing for a full day of working and studying, then travelling along crowed boulevards or narrow streets filled with motor scooters and returning home after a busy day. They usually live in large houses, or high-rise apartment blocks or even in a small rental room equipped with modern facilities, like the Internet, telephone, television, and so on. Industrialization and modernization as well as global integration have big impact on lifestyle in the cities. The most noticeable impact is the Western style of clothes. The "Ao dai” - Vietnamese traditional clothes are no longer regularly worn in Vietnamese women's daily life. Instead, jeans, T-shirts and fashionable clothes are widely and modernization may lead to A some changes in the fact that women no longer wear ao the disappearance of Western-styled clothes. Unlike life in the countryside which is often considered to be simple and traditional, life in the city is modern and complicated. People, from different regions, move to the cities in the hope of having a better life for them and their children. The inhabitants in city work as secretaries, businessmen, teachers, government workers, factory workers and even street vendors or construction workers. The high cost of living requires city dwellers, especially someone with low income, to work harder or to take a part-time job. For many people, an ordinary day starts as usual by getting up in the early morning to do exercise in public parks, preparing for a full day of working and studying, then travelling along crowed boulevards or narrow streets filled with motor scooters and returning home after a busy day. They usually live in large houses, or high-rise apartment blocks or even in a small rental room equipped with modern facilities, like the Internet, telephone, television, and so on. Industrialization and modernization as well as global integration have big impact on lifestyle in the cities. The most noticeable impact is the Western style of clothes. The "Ao dai” - Vietnamese traditional clothes are no longer regularly worn in Vietnamese women's daily life. Instead, jeans, T-shirts and fashionable clothes are widely word "impact" in paragraph 2 is closest in meaning to .I don’t have a map, so I can’t show you the I would show you the way if I had a map. B Unless you give me a map, I won’t show you the I would have a map if I showed you the way. D Unless you have a map, I can show you the of his tiredness, Nam couldn't finish his Nam couldn't finish his homework because he was Nam couldn't finish his homework because he is Nam could finish his homework, so he was tired. D Nam couldn't finish his homework because he was a pity that this school year will not finish as I wish that this school year would finish as plannedB I wish that this school year finished as planned. C I wish that this school year will finish as I wish that this school year would not finish as is better at English than Linh doesn't learn English so well as Nam Nam learns English worse than Nam isn’t as good at English as Linh isn’t as bad at English as took shelter in a store …………. the rainstorm. I’m fluent …………..three letter A, B, C, or D to indicate the word OPPOSITE in meaning to the underlined petrol prices keep going up like this, I’ll have to use a bicycle. Peter “I'm taking my TOEFL test tomorrow.”Daisy “…………..”Have you ever considered…………….a pharmacist?She……….. a new computer last week, so did her friend. ScienceNot Exactly Rocket ScienceIn 1958, a young scientist called Stanley Miller electrified a mixture of simple gases, designed to mimic the atmosphere of our primordial lifeless planet. It was a sequel to one of the most evocative experiments in history, one that Miller himself had carried five years earlier. But for some reason, he never finished his follow-up. He dutifully collected his samples and stored them in vials but, whether for ill health or dissatisfaction, he never analysed vials languished in obscurity, sitting unopened in a cardboard box in Miller’s office. But possessed by the meticulousness of a scientist, he never threw them away. In 1999, the vials changed owners. Miller had suffered a stroke and bequeathed his old equipment, archives and notebooks to Jeffrey Bada, one of his former students. Bada only twigged to the historical treasures that he had inherited in 2007. “Inside, were all these tiny glass vials carefully labeled, with page numbers referring Stanley’s laboratory notes. I was dumbstruck. We were looking at history,” he said in a New York Times then, Miller was completely incapacitated. He died of heart failure shortly after, but his legacy continues. Bada’s own student Eric Parker has finally analysed Miller’s samples using modern technology and published the results, completing an experiment that began 53 years conducted his original 1953 experiment as a graduate student, working with his mentor Harold Urey. It was one of the first to tackle the seemingly insurmountable question of how life began. In their laboratory, the pair tried to recreate the conditions on early lifeless Earth, with an atmosphere full of simple gases and laced with lightning storms. They filled a flask with water, methane, ammonia and hydrogen and sent sparks of electricity through result, both literally and figuratively, was lightning in a bottle. When Miller looked at the samples from the flask, he found five different amino acids – the building blocks of proteins and essential components of relevance of these results to the origins of life is debatable, but there’s no denying their influence. They kicked off an entire field of research, graced the cover of Time magazine and made a celebrity of Miller. Nick Lane beautifully describes the reaction to the experiment in his book, Life Ascending “Miller electrified a simple mixture of gases, and the basic building blocks of life all congealed out of the mix. It was as if they were waiting to be bidden into existence. Suddenly the origin of life looked easy.”Over the next decade, Miller repeated his original experiment with several twists. He injected hot steam into the electrified chamber to simulate an erupting volcano, another mainstay of our primordial planet. The samples from this experiment were among the unexamined vials that Bada inherited. In 2008, Bada’s student Adam Johnson showed that the vials contained a wider range of amino acids than Miller had originally reported in also tweaked the gases in his electrified flasks. He tried the experiment again with two newcomers – hydrogen sulphide and carbon dioxide – joining ammonia and methane. It would be all too easy to repeat the same experiment now. But Parker and Bada wanted to look at the original samples that Miller had himself collected, if only for their “considerable historical interest”.Using modern techniques, around a billion times more sensitive than those Miller would have used, Parker identified 23 different amino acids in the vials, far more than the five that Miller had originally described. Seven of these contained sulphur, which is either a first for science or old news, depending on how you look at it. Other scientists have since produced sulphurous amino acids in similar experiments, including Carl Sagan. But unbeknownst to all of them, Miller had beaten them to it by several years. He had even scooped himself – it took him till 1972 to publish results where he produced sulphur amino acids!The amino acids in Miller’s vials all come in an equal mix of two forms, each the mirror image of the other. You only see that in laboratory reactions – in nature, amino acids come almost entirely in one version. As such, Parker, like Miller before him, was sure that the amino acids hadn’t come from a contaminating source, like a stray bacterium that had crept into the then, a young and violent planet, wracked with exploding volcanoes, noxious gases and lightning strikes. These ingredients combined to brew a “primordial soup”, fashioning the precursors of life in pools of water. On top of that, meteorites raining down from space could have added to the accumulating molecules. After all, Parker found that the amino acid cocktail in Miller’s samples is very similar to that found on the Murchison meteorite, which landed in Australia in are powerful images, so why aren’t people more excited? Echoing many sources I spoke to, Jim Kasting, who studies the evolution of Earth’s atmosphere, said, “I am underwhelmed by it.” The main problem with the study is that Miller was probably wrong about the conditions on early analysing ancient rocks, scientists have since found that Earth was never particularly teeming in hydrogen-rich gases like methane, hydrogen sulphide or hydrogen itself. If you repeat Miller’s experiment with a more realistic mixture – heavy in carbon dioxide and nitrogen, with just trace amounts of other gases – you’d have a hard time finding amino acids in the resulting accepts the problem, but he suggests that a few specific places on the planet may have had the right conditions. Exploding volcanoes, for example, throw up masses of sulphurous compounds, as well as methane and ammonia. These gases, belched forth into lightning storms, could have produced amino acids that rained out and gathered in tidal pools. But Kasting still isn’t convinced. “Even then the reduced gases would not be as concentrated as they are in this experiment.”Even if our young planet had the right conditions to produce amino acids, that’s a less impressive feat than it appeared in the 1950s. “Amino acids are old hat and are a million miles from life,” says Nick Lane. Indeed, as Miller’s experiments showed, it’s not difficult to create amino acids. The far bigger challenge is to create nucleic acids – the building blocks of molecules like RNA and DNA. The origin of life lies in the origin of these “replicators”, molecules that can make copies of themselves. Lane says, “Even if you can make amino acids and nucleic acids under soup conditions, it has little if any bearing on the origin of life.”The problem is that replicators don’t spontaneously emerge from a mixture of their building blocks, just as you wouldn’t hope to build a car by throwing some parts into a swimming pool. Nucleic acids are innately “shy”. They need to be strong-armed into forming more complex molecules, and it’s unlikely that the odd bolt of lightning would have been enough. The molecules must have been concentrated in the same place, with a constant supply of energy and catalysts to speed things up. “Without that lot, life will never get started, and a soup can’t provide much if any of that,” says vents are a better location for the origins of life. Deep under the ocean’s surface, these rocky chimneys spew out superheated water and hydrogen-rich gases. Their rocky structures contain a labyrinth of small compartments that could have concentrated life’s building blocks into dense crowds, and minerals that would have catalysed their get-togethers. Far away from visions of languid soups, these churning environments are the current best guess for the site of life’s Miller’s iconic experiment, and its now-completed follow-ups, probably won’t lay out the first steps of life. As Adam Rutherford, who is writing a book on the origin of life, says, “It’s really a historical piece, like finding that Darwin had described a Velociraptor in one of his notebooks.”If anything, the analysis of Miller’s vials is a testament to the value of meticulous scientific work. Here was a man who prepared his samples so cleanly, who recorded his notes so thoroughly, and who stored everything so carefully, that his contemporaries could pick up where he left off five decades Parker, Cleaves, Dworkin, Glavin, Callahan, Aubrey, Lazcano & Bada. 2011. Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment. PNAS by Carlos Gutierrez and Marco FulleMore on origins A possible icy start for lifeTree or ring the origin of complex cellsThe origin of complex life – it was all about energy In 1952, atomic scientists came together on the 10th anniversary of the first controlled nuclear fission chain reaction, which took place Dec. 2, 1942, at the University of Chicago. Courtesy of University of Chicago Photographic Archive hide caption toggle caption Courtesy of University of Chicago Photographic Archive In 1952, atomic scientists came together on the 10th anniversary of the first controlled nuclear fission chain reaction, which took place Dec. 2, 1942, at the University of Chicago. Courtesy of University of Chicago Photographic Archive Seventy-five years ago this week, scientists from the University of Chicago created the first controlled, self-sustained nuclear chain reaction, a feat that was essential in the development of an atomic bomb during World War II. Enrico Fermi and his team of physicists secretly conducted the Chicago Pile 1 experiment on a squash court under the stands of a football stadium on Dec. 2, 1942. The anniversary of this unprecedented achievement comes as tensions escalate between the and North Korea, which launched a new ballistic missile on Tuesday. The 1942 test was a crucial first step in the creation of nuclear weapons by the endeavor known as the Manhattan Project, says Eric Isaacs, executive vice president of research, innovation and national laboratories at the University of Chicago. "The way I like to think about it is It was not enough to power a light bulb, but it changed the world," he tells Here & Now's Jeremy Hobson. "It changed, obviously, the world because the war ended some years later with the bomb." Enrico Fermi, a professor of physics at the University of Chicago and the winner of the 1938 Nobel Prize in physics, led the team of scientists which succeeded in obtaining the first controlled, self-sustaining nuclear chain reaction on Dec. 2, 1942. Courtesy of Argonne National Laboratory hide caption toggle caption Courtesy of Argonne National Laboratory The coordinated effort to harness nuclear energy began in 1939 after scientists in Europe demonstrated fission of a nucleus for the first time, Isaacs explains. Many scientists in the were expatriates, some of whom were refugees from fascist Europe, and they quickly realized the potential that Germany could build a bomb. According to NPR contributor Marcelo Gleiser, Hungarian physicist Leó Szilárd first proposed the idea of a nuclear chain reaction, "whereby neutrons released from radioactive atomic nuclei would hit other heavy nuclei causing them to split fission into smaller nuclei. Every time this splitting happened, a little bit of energy was released. "Szilárd knew that the possibility of a chain reaction represented a shift in world history," Gleiser, a professor of physics at Dartmouth College, writes. "An explosive device with an uncontrolled chain reaction would have devastating consequences." A group of scientists persuaded Albert Einstein, the most famous scientist of the day, to write President Franklin Roosevelt urging him to launch a major bomb-making effort. The letter essentially said, "If we don't build a bomb, Germany will first." Fermi's pile experiment, which served as the framework for modern nuclear reactors, generated only about a half watt of power, University of Pennsylvania physics and astronomy professor Gino Segre writes in the Chicago Tribune The experiment focused on a crude pile — a 20-foot-high structure made of close to 40,000 graphite bricks, weighing 20 pounds each and embedded with a total of almost 100,000 pounds of uranium. Thirteen-foot control rods, ready to be pushed in or out depending on the neutron count, protruded from the pile. Fermi, cool and collected throughout the experiment, gave orders from the balcony above the squash court. The 49 attending scientists and observers fully trusted this Nobel Prize winner, called the "Pope of Physics" by his admiring peers because of his scientific infallibility. At 325 in the afternoon, after ordering the last control rod to be pulled halfway out, Fermi announced the pile had "gone critical." The chain reaction gradually accelerated, reaching dangerous levels ever more quickly. After the neutron count dramatically intensified at 349 Fermi continued to run the pile for nearly 5 minutes before calling a halt to the experiment. But those minutes marked the beginning of a new era. A drawing of Chicago Pile 1, the nuclear reactor that scientists used to achieve the first controlled, self-sustaining chain reaction on Dec. 2, 1942. Courtesy of Argonne National Laboratory hide caption toggle caption Courtesy of Argonne National Laboratory A drawing of Chicago Pile 1, the nuclear reactor that scientists used to achieve the first controlled, self-sustaining chain reaction on Dec. 2, 1942. Courtesy of Argonne National Laboratory While the reaction only produced a small amount of energy, Isaacs says the event was a "remarkable engineering feat" that dramatically changed the landscape of science. Three years later, the dropped the first atomic bomb on the Japanese city of Hiroshima. Despite the unprecedented destruction created by the bomb, Isaacs says nuclear power plants, as well as other nuclear materials, wouldn't exist without Fermi's experiment. The experiment demonstrated that generating "nuclear power releasing the energy of one nucleus is not nearly enough," Isaacs explains. "You have to re-release the energy of many, many nuclei to create the kind of energy that are required for nuclear-produced electricity." At a time when there is rising concern about the temperament of world leaders in control of nuclear weapons, Isaacs says the scientists who worked on the pile experiment "realized the devastating consequences of the kind of energy they could release with fission." But the fear that drove them to move forward, Isaacs says, fundamentally changed the role of science in our society. "There were very loud debates going on amongst the scientists about whether we should use a bomb, whether we shouldn't use a bomb, how it should be done," he says, "and in fact, out of World War II, one of the things that emerged was the engagement of scientists in discussions around policy."

some time ago scientists began experiments