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| SCIENCE & TECHNOLOGY |
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Global warming
Monkeys good at mental math
World’s first ship tunnel
Trends
PROF YASH PAL When we throw a stone while travelling in car, it gets more force than the ordinary throw. Why? The answer to this question should be obvious. If car were travelling at 120 kilometers per hour then a stone dropped out by a child would be traveling at the same speed; this is similar to that of a ball thrown by some of the best fast bowlers in cricket. |
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Global warming
Almost all the coral reefs in the world will disappear by the end of the century if global temperatures continue to rise as predicted by the Intergovernmental Panel on Climate Change (IPCC), a study has found. Rising temperatures and an increase in the acidity of the oceans will make it impossible for tiny coral organisms to make their calcium-based shells, according to the most definitive review yet of how well coral reefs will cope with global warming. Scientist predict that unless countries drastically curb their emissions of carbon dioxide, some of the biggest reefs with the highest biodiversity, such as the Great Barrier Reef of Australia and the spectacular corals of the Caribbean, will become underwater deserts within the lifetime of people alive today. A group of 17 eminent scientists from seven countries came to the pessimistic assessment after studying the worldwide scientific literature on rising concentrations of carbon dioxide, ocean acidity and global temperatures. The study concluded that the expected increase in carbon dioxide this century will make earth uninhabitable for the vast majority of coral reefs. As a result, it will put intolerable pressure on the hundreds of millions of people who rely on the reefs for their livelihoods. “This crisis is on our doorstep, not decades away,” said Prof Peter Mumby, of Exeter University. “Unless we act now, coral reefs are likely to dwindle into insignificance. They’ll be reduced to seaweed beds, rubble and a few scattered corals. “The livelihoods of many millions of people living along the coasts of tropical developing countries will be among the first major casualties of rising levels of carbon in the atmosphere,” said Professor Mumby, one of the authors of the report published in the journal Science. Corals suffer from increasing levels of carbon dioxide on two fronts. Rising temperatures cause “bleaching”, when the symbiotic algae that lives within the coral is expelled. Secondly, CO2 dissolving in the oceans boosts acidity which prevents the process of shell formation. Current levels of carbon dioxide in the atmosphere are running at about 383 parts per million, but the IPCC predicts that that is likely to increase to at least 500ppm, with a corresponding 2C increase in global average temperatures by 2100. About a third of the extra carbon dioxide added to the atmosphere by human activities is dissolved in the oceans which increases the concentration of carbonic acid. This extra acidity dissolves certain carbonate minerals in seawater, notably a mineral called aragonite which is used by corals to make their external calcium skeleton. “Before the industrial revolution, more than 98 per cent of warm water coral reefs were bathed with open ocean waters 3.5 times supersaturated with aragonite, meaning that corals could easily extract it to build reefs,” said Long Cao, a marine researcher at the Carnegie Institution in Stanford, California. “But if atmospheric carbon dioxide stabilises at 550ppm, and even that would take concerted international effort to achieve, no existing coral reef will remain in such an environment.” Professor Mumby said levels of carbon dioxide were higher now than they have been for at least 740,000 years, and possibly higher than at any time in the past 20 million years. “Coral reefs are the largest living structures on earth and are home to the highest biodiversity on the planet,” said Professor Mumby. “The environment that has enabled coral reefs to thrive for hundreds of thousands of years is changing so fast that compensatory biological responses are lagging behind. “Better conservation, such as enforcement of fisheries regulations, is essential in order to buy time for coral reefs. If we can reduce local stresses and simultaneously curb carbon dioxide emissions to within 450ppm, then coral reefs and the food and housing security of millions of people could yet be saved.” Professor Ken Caldeira, of the Carnegie Institution, another of the authors of the study, said: “These changes come at a time when reefs are already stressed by climate change, overfishing and other types of pollution. So unless we take action soon there is a very real possibility that coral reefs, and everything that depends on them, will not survive this century.” — The Independent |
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Trends
A “death star” galaxy is sending out a powerful jet of particles and magnetic radiation that is likely obliterating any possible life in its broad path, notably in a nearby galaxy, astronomers said on Monday.
They said the two galaxies appear to be merging and the disturbance in the magnetic field caused by this movement may have awakened a dormant, supermassive black hole in one of the galaxies. They have images of the deadly blast, spurting out from a system known as 3C321. Data from NASA’s Chandra X-ray Observatory show both galaxies have supermassive black holes at their centers, and 3C321, the larger galaxy, is emitting this stream of energy and particles. The unnamed smaller galaxy apparently has swung into the path of this jet. The astronomers agree that both galaxies are likely to have planetary systems but nothing resembling life on any planet could survive the blast. While such jets have been seen before, this is the first time one has been observed battering another galaxy, the researchers report in The Astrophysical Journal.
— Reuters
Giant rats in Indonesia
Unearthing new species of mammals in the 21st century is considered very rare. The discoveries by a team of American and Indonesian scientists are being studied further to confirm their status. The animals were found in the Foja mountains rainforest in eastern Papua province in a June expedition, said US-based Conservation International, which organised the trip in the Southeast Asian nation along with the Indonesian Institute of Science. “The giant rat is about five times the size of a typical city rat,” said Kristofer Helgen, a scientist with the Smithsonian Institution in Washington. “With no fear of humans, it apparently came into the camp several times during the trip.” The possum was described as “one of the world’s smallest marsupials.” A 2006 expedition to the same stretch of jungle — dubbed by Conservation International as a “Lost World” because until then humans had rarely visited it — unearthed scores of exotic new species of palms, butterflies and palms.
— AP
Clone cats that glow
Three Turkish Angora cats were born in January and February through cloning with a gene that produces a red fluorescent protein that makes them glow in dark. One died at birth, but the two others survived, the ministry said.
— AP
Fearless mice of Japan
Scientists at Tokyo University say they were able to successfully switch off a mouse’s instinct to cower at the smell or presence of cats — showing that fear is genetically hardwired and not learned through experience, as commonly believed. “Mice are naturally terrified of cats, and usually panic or flee at the smell of one. But mice with certain nasal cells removed through genetic engineering didn’t display any fear,” said research team leader Ko Kobayakawa.
— AP |
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THIS UNIVERSE When we throw a stone while travelling in car, it gets more force than the ordinary throw. Why? The answer to this question should be obvious. If car were travelling at 120 kilometers per hour then a stone dropped out by a child would be traveling at the same speed; this is similar to that of a ball thrown by some of the best fast bowlers in cricket. So if the stone is thrown forward through the car window, the speed of the car gets added to the speed at which you throw. You also know that fast bowlers in cricket take a long fast run before throwing the ball. They are adding their running speed to that at which they can throw just standing still on the ground. If we drink coffee or tea after eating sweets, they seem to be much less sweet. What is the reason? I will hazard an answer even though I am not so certain about its accuracy. Taste buds are receptors that fit in the molecules that give us a sensation of sweetness. After eating things that are very sweet these receptors are saturated with molecules. There are few seats that are vacant. Therefore the signal of sweetness from things that are less sweet remains weak. Therefore things taste less sweet than they would if we had not taken the sweets beforehand. In electrical wiring, what is the difference between the neutral and the ground? The ground is connected to the ground and the neutral is not. The ground wire ensures that in case of a leakage a connected appliance does not acquire a voltage that might cause injury or malfunction. The live terminal is the one to which the voltage is connected. It appears that there should be no separate identification of the live and neutral terminals when you are dealing with ac current. However for reasons of safety and connecting electrical networks it becomes prudent to do so.
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