As important as Darwin
Aug 13th 2009
From The Economist print edition
In praise of astronomy, the most revolutionary of sciences
MEPL
FOUR hundred years ago our understanding of the universe changed for ever. On August 25th 1609 an Italian mathematician called Galileo Galilei demonstrated his newly constructed telescope to the merchants of Venice. Shortly afterwards he turned it on the skies. He saw mountains casting shadows on the moon and realised this body was a world, like the Earth, endowed with complicated terrain. He saw the moons of Jupiter—objects that circled another heavenly body in direct disobedience of the church’s teaching. He saw the moonlike phases of Venus, indicating that this planet circled the sun, not the Earth, in even greater disobedience of the priests. He saw sunspots, demonstrating that the sun itself was not the perfect orb demanded by the Greek cosmology that had been adopted by the church. But he also saw something else, a thing that is often now forgotten. He saw that the Milky Way, that cloudy streak across the sky, is made of stars.
That observation was the first hint that, not only is the Earth not the centre of things, but those things are vastly, almost incomprehensibly, bigger than people up until that date had dreamed. And they have been getting bigger, and also older, ever since. Astronomers’ latest estimates put the age of the universe at about 13.7 billion years. That is three times as long as the Earth has existed and about 100,000 times the lifespan of modern humanity as a species. The true size of the universe is still unknown. Its age, and the finite speed of light, means no astronomer can look beyond a distance of 13.7 billion light-years. But it is probably bigger than that.
Nor does reality necessarily end with this universe. Physics, astronomy’s dutiful daughter, suggests that the object that people call the universe, vast though it is, may be just one of an indefinite number of similar structures, governed by slightly different rules from each other, that inhabit what is referred to, for want of a better term, as the multiverse.
sábado, 15 de agosto de 2009
Whatever happened to the food crisis?
Whatever happened to the food crisis?
Jul 2nd 2009
From The Economist print edition
It crept back
MULUALEM TEGEGN bought a donkey last year. As a hard-working Ethiopian farmer, aged 58, he saw the purchase of the beast as a return to better times after several seasons in which drought and high prices had forced him to sell his livestock and take his grandchildren out of school to work on the farm. This year, he will have enough grain left to buy a goat or two, and the donkey will help the children make the long trek again to school. This is how things are supposed to be.
World food prices soared in 2007-08, pushing hundreds of millions into poverty. But—said people at the time—there was a silver lining: high prices would be good for farmers, especially smallholders in poor countries such as Mr Tegegn. Higher returns would suck money into farming, leading to higher yields, bigger harvests and stable or falling food prices. Eventually, the argument ran, farmers and consumers would all be better off.
This happy state of affairs seemed to be coming to pass in the second half of 2008. Ethiopia reported a record cereals harvest this January, up 10% on the previous year. Across the world, the picture was similar. After the price spike in the first half of 2008, farmers harvested 2.3 billion tonnes of cereals in 2008/09, the biggest crop ever seen. Big exporters began lifting the trade bans they had imposed to keep local prices from rising, so more food became available to world markets. The sharp fall in the price of oil, which occurred at the same time, increased food supplies further because, by making oil cheaper than ethanol, it encouraged farmers to sell for feed the maize they would otherwise have turned into biofuels. As food supplies surged (and demand, hit by the global recession, stagnated), prices plummeted. Between its peak in July and a trough in December 2008, The Economist’s index of food prices fell by 40%.
All that seems fairly rational and hopeful. But this year’s changes have been more puzzling. Between December and mid-June, the food index rebounded by a third, even though this year’s total cereals crop is expected to be another bumper (2.2 billion tonnes, says the Food and Agriculture Organisation, second only to 2008/09, see chart left). Meanwhile, soyabean and sugar prices have risen by nearly half from trough to peak—see chart below—and the index of “non-food agriculturals” (plants such as cotton or rubber) also rose by a quarter between December and mid-June. Prices have been increasing at a time of plenty
Jul 2nd 2009
From The Economist print edition
It crept back
MULUALEM TEGEGN bought a donkey last year. As a hard-working Ethiopian farmer, aged 58, he saw the purchase of the beast as a return to better times after several seasons in which drought and high prices had forced him to sell his livestock and take his grandchildren out of school to work on the farm. This year, he will have enough grain left to buy a goat or two, and the donkey will help the children make the long trek again to school. This is how things are supposed to be.
World food prices soared in 2007-08, pushing hundreds of millions into poverty. But—said people at the time—there was a silver lining: high prices would be good for farmers, especially smallholders in poor countries such as Mr Tegegn. Higher returns would suck money into farming, leading to higher yields, bigger harvests and stable or falling food prices. Eventually, the argument ran, farmers and consumers would all be better off.
This happy state of affairs seemed to be coming to pass in the second half of 2008. Ethiopia reported a record cereals harvest this January, up 10% on the previous year. Across the world, the picture was similar. After the price spike in the first half of 2008, farmers harvested 2.3 billion tonnes of cereals in 2008/09, the biggest crop ever seen. Big exporters began lifting the trade bans they had imposed to keep local prices from rising, so more food became available to world markets. The sharp fall in the price of oil, which occurred at the same time, increased food supplies further because, by making oil cheaper than ethanol, it encouraged farmers to sell for feed the maize they would otherwise have turned into biofuels. As food supplies surged (and demand, hit by the global recession, stagnated), prices plummeted. Between its peak in July and a trough in December 2008, The Economist’s index of food prices fell by 40%.
All that seems fairly rational and hopeful. But this year’s changes have been more puzzling. Between December and mid-June, the food index rebounded by a third, even though this year’s total cereals crop is expected to be another bumper (2.2 billion tonnes, says the Food and Agriculture Organisation, second only to 2008/09, see chart left). Meanwhile, soyabean and sugar prices have risen by nearly half from trough to peak—see chart below—and the index of “non-food agriculturals” (plants such as cotton or rubber) also rose by a quarter between December and mid-June. Prices have been increasing at a time of plenty
domingo, 2 de agosto de 2009
THE SCIENCE OF SMILES
THE SCIENCE OF SMILES
By Larry Greenemeier in 60-Second Science Blog
Jul 30, 2009 04:45 PM Scientific American
How does your smile rate on a scale of zero to 100? If you worked for Japan's Keihin Electric Express Railway Co., you'd know—on a daily basis.
The Tokyo-based train company is using a "Smile Scan" system to evaluate the grins of its 530 station staffers at 15 stations when they report to work each day, Japan's Mainichi Daily News reported earlier this month. The smiles (including eye movements, lip curves and wrinkles) are scored on a scale ranging from zero (scowling=irritado) to 100 (glowing) using a camera and computer provided by Kyoto-based Omron Corp., with low scores earning employees automatically generated advice such as, "You still look too serious," or "Lift up your mouth corners."
The railway network covers 87 kilometers and serves an average of 1.2 million passengers daily. The idea is for workers to print out and carry around an image of their best smile in an attempt to remember and replicate it as they encounter customers throughout their shifts.
Image ©iStockphoto.com/ pidjoe
By Larry Greenemeier in 60-Second Science Blog
Jul 30, 2009 04:45 PM Scientific American
How does your smile rate on a scale of zero to 100? If you worked for Japan's Keihin Electric Express Railway Co., you'd know—on a daily basis.
The Tokyo-based train company is using a "Smile Scan" system to evaluate the grins of its 530 station staffers at 15 stations when they report to work each day, Japan's Mainichi Daily News reported earlier this month. The smiles (including eye movements, lip curves and wrinkles) are scored on a scale ranging from zero (scowling=irritado) to 100 (glowing) using a camera and computer provided by Kyoto-based Omron Corp., with low scores earning employees automatically generated advice such as, "You still look too serious," or "Lift up your mouth corners."
The railway network covers 87 kilometers and serves an average of 1.2 million passengers daily. The idea is for workers to print out and carry around an image of their best smile in an attempt to remember and replicate it as they encounter customers throughout their shifts.
Image ©iStockphoto.com/ pidjoe
A Patchwork Mind: How Your Parents' Genes Shape Your Brain
A Patchwork Mind: How Your Parents' Genes Shape Your Brain
We each have two parents, but their genetic contributions to what makes us us are uneven. New research shows we are an amalgam of influences from mom and dad
By Melinda Wenner From the July 30, 2009 Scientific American Mind
• When passing on DNA to their offspring, mothers silence certain genes, and fathers silence others. These imprinted genes usually result in a balanced, healthy brain, but when the process goes awry(errado), neurological disorders can result.
• Imprinting errors are responsible for rare disorders such as Angelman and Prader-Willi syndromes, and some scientists are beginning to think imprinting might be implicated in more common illnesses such as autism and schizophrenia.
• Even typical brains are the result of asymmetric contributions from Mom and Dad. Higher cognitive function seems to be disproportionately controlled by Mom’s genes, whereas the drive to eat and mate is influenced by Dad’s.
We each have two parents, but their genetic contributions to what makes us us are uneven. New research shows we are an amalgam of influences from mom and dad
By Melinda Wenner From the July 30, 2009 Scientific American Mind
• When passing on DNA to their offspring, mothers silence certain genes, and fathers silence others. These imprinted genes usually result in a balanced, healthy brain, but when the process goes awry(errado), neurological disorders can result.
• Imprinting errors are responsible for rare disorders such as Angelman and Prader-Willi syndromes, and some scientists are beginning to think imprinting might be implicated in more common illnesses such as autism and schizophrenia.
• Even typical brains are the result of asymmetric contributions from Mom and Dad. Higher cognitive function seems to be disproportionately controlled by Mom’s genes, whereas the drive to eat and mate is influenced by Dad’s.
Imaginary Friends
Imaginary Friends
Television programs can fend off loneliness
By Fionnuala Butler and Cynthia Pickett July 28, 2009 |Scientific American
By yourself, but not alone Flickering friends count for something
Stomach growling, but have no time for a meal? A snack will do. Drowsy and unable to concentrate? A short nap can be reviving when a good night’s rest is unavailable. But what should you do when you are alone and feeling lonely?
New psychological research suggests that loneliness can be alleviated by simply turning on your favorite TV show. In the same way that a snack can satiate hunger in lieu of a meal, it seems that watching favorite TV shows can provide the experience of belonging without a true interpersonal interaction.
For decades, psychologists have been interested in understanding how individuals achieve and maintain social relationships in order to ward off social isolation and loneliness. The vast majority of this research has focused on relationships between real individuals interacting face-to-face. Recent research has widened this focus from real relationships to faux, “parasocial” relationships. Parasocial relationships are the kind of one sided pseudo-relationships we develop over time with people or characters we might see on TV or in the movies. So, just as a friendship evolves through spending time together and sharing personal thoughts and opinions, parasocial relationships evolve by watching characters on our favorite TV shows, and becoming involved with their personal lives, idiosyncrasies, and experiences as if they were those of a friend.
In a recent article published in the Journal of Experimental Social Psychology, Jaye Derrick and Shira Gabriel of the University of Buffalo and Kurt Hugenberg of Miami University test what they call the “Social Surrogacy Hypothesis.”
Television programs can fend off loneliness
By Fionnuala Butler and Cynthia Pickett July 28, 2009 |Scientific American
By yourself, but not alone Flickering friends count for something
Stomach growling, but have no time for a meal? A snack will do. Drowsy and unable to concentrate? A short nap can be reviving when a good night’s rest is unavailable. But what should you do when you are alone and feeling lonely?
New psychological research suggests that loneliness can be alleviated by simply turning on your favorite TV show. In the same way that a snack can satiate hunger in lieu of a meal, it seems that watching favorite TV shows can provide the experience of belonging without a true interpersonal interaction.
For decades, psychologists have been interested in understanding how individuals achieve and maintain social relationships in order to ward off social isolation and loneliness. The vast majority of this research has focused on relationships between real individuals interacting face-to-face. Recent research has widened this focus from real relationships to faux, “parasocial” relationships. Parasocial relationships are the kind of one sided pseudo-relationships we develop over time with people or characters we might see on TV or in the movies. So, just as a friendship evolves through spending time together and sharing personal thoughts and opinions, parasocial relationships evolve by watching characters on our favorite TV shows, and becoming involved with their personal lives, idiosyncrasies, and experiences as if they were those of a friend.
In a recent article published in the Journal of Experimental Social Psychology, Jaye Derrick and Shira Gabriel of the University of Buffalo and Kurt Hugenberg of Miami University test what they call the “Social Surrogacy Hypothesis.”
sexta-feira, 24 de julho de 2009
Is your cat left or right pawed?
Is your cat left or right pawed?
10:28 24 July 2009 by Ewen Callaway New Scientist
For similar stories, visit the The Human Brain
Raise your best paw (Image: Image Source / Rex Features)
It may not be obvious from the scratch marks cats dish out, but domestic felines favour one paw over the other. More often than not, females tend to be righties, while toms are lefties, say Deborah Wells and Sarah Millsopp, psychologists at Queen's University Belfast in Northern Ireland.
However, these preferences only manifest when cats perform particularly dexterous feats. That's for the same reason we can open a door with either arm, yet struggle to write legibly with our non-dominant hand. "The more complex and challenging [the task], the more likely we're going to see true handedness," Wells says.
She and Millsopp tasked 42 domestic cats to ferret out a bit of tuna in a jar too small for their heads. Among 21 females, all but one favoured the right paw across dozens of trials, while 20 out of 21 males preferentially used the left. One male proved ambidextrous.
Not so for two simpler activities: pawing at a toy mouse suspended in the air or dragged on ground from a string. No matter their sex, all of the cats wielded their right and left paws about equally on these less demanding tasks.
Hormone levels could explain sex differences in paw choice, Wells says. Previous research has linked prenatal testosterone exposure to left-handedness. While studies of two other domestic animals, dogs and horses, revealed similar sex biases.
10:28 24 July 2009 by Ewen Callaway New Scientist
For similar stories, visit the The Human Brain
Raise your best paw (Image: Image Source / Rex Features)
It may not be obvious from the scratch marks cats dish out, but domestic felines favour one paw over the other. More often than not, females tend to be righties, while toms are lefties, say Deborah Wells and Sarah Millsopp, psychologists at Queen's University Belfast in Northern Ireland.
However, these preferences only manifest when cats perform particularly dexterous feats. That's for the same reason we can open a door with either arm, yet struggle to write legibly with our non-dominant hand. "The more complex and challenging [the task], the more likely we're going to see true handedness," Wells says.
She and Millsopp tasked 42 domestic cats to ferret out a bit of tuna in a jar too small for their heads. Among 21 females, all but one favoured the right paw across dozens of trials, while 20 out of 21 males preferentially used the left. One male proved ambidextrous.
Not so for two simpler activities: pawing at a toy mouse suspended in the air or dragged on ground from a string. No matter their sex, all of the cats wielded their right and left paws about equally on these less demanding tasks.
Hormone levels could explain sex differences in paw choice, Wells says. Previous research has linked prenatal testosterone exposure to left-handedness. While studies of two other domestic animals, dogs and horses, revealed similar sex biases.
Heart, heal thyself
Heart, heal thyself
A mouse study finds that, surprisingly, heart muscle can be made to proliferate.
Monya Baker 23 July 2009 | Nature
A protein factor may give adult heart muscle cells a new lease of life.R. Bick, B. Poindexter, UT Medical School / Science Photo Library
With a little prompting, adult hearts may be able to heal themselves — at least, they may do if a recent study in mice holds true for humans. The heart has long been considered one of the organs least capable of regenerating after injury, with heart transplants one of the few effective therapies available. But now a team led by Bernhard Kühn at the Children's Hospital and Harvard Medical School in Boston, Massachusetts, has shown that protein injections in mice not only prompt heart muscle cells, known as cardiomyocytes, to proliferate, but that this proliferation also reduces damage after a heart attack1.
"This is of major, major consequence if it turns out to be correct," says Deepak Srivastava, director of the Gladstone Institute of Cardiovascular Disease in San Francisco, California. "There have been no reports of differentiated cardiomyocytes in the adult being able to re-enter the cell cycle and divide again."
Work published earlier this year showed that the heart does indeed make new cardiomyocytes in adulthood. But because the replacement rate is very low and the source of new cells unknown, whether this finding would prove useful for treating heart disease was unclear. Kühn, a practising pediatric cardiologist, says he is already working to turn his finding into a potential therapy2.
To hunt for factors that could cause adult tissue to make new cardiomyocytes, Kühn and his colleagues isolated heart cells from adult rats and exposed them to proteins already known to prompt fetal tissue to build hearts. Their search identified the well-studied protein neuregulin 1. Kühn's team then turned to mice, simulating heart attacks in dozens of them by tying off a major artery feeding the heart before giving half of them abdominal injections of neuregulin 1 for 12 weeks. After waiting two weeks for the direct effects of neuregulin 1 to wear off, the researchers found that scars resulting from the heart attack were 46% smaller in treated than untreated mice. Additionally, hearts in treated mice displayed less of the weakening cell overgrowth that is typically observed after a heart attack, and they could even pump more blood.
A mouse study finds that, surprisingly, heart muscle can be made to proliferate.
Monya Baker 23 July 2009 | Nature
A protein factor may give adult heart muscle cells a new lease of life.R. Bick, B. Poindexter, UT Medical School / Science Photo Library
With a little prompting, adult hearts may be able to heal themselves — at least, they may do if a recent study in mice holds true for humans. The heart has long been considered one of the organs least capable of regenerating after injury, with heart transplants one of the few effective therapies available. But now a team led by Bernhard Kühn at the Children's Hospital and Harvard Medical School in Boston, Massachusetts, has shown that protein injections in mice not only prompt heart muscle cells, known as cardiomyocytes, to proliferate, but that this proliferation also reduces damage after a heart attack1.
"This is of major, major consequence if it turns out to be correct," says Deepak Srivastava, director of the Gladstone Institute of Cardiovascular Disease in San Francisco, California. "There have been no reports of differentiated cardiomyocytes in the adult being able to re-enter the cell cycle and divide again."
Work published earlier this year showed that the heart does indeed make new cardiomyocytes in adulthood. But because the replacement rate is very low and the source of new cells unknown, whether this finding would prove useful for treating heart disease was unclear. Kühn, a practising pediatric cardiologist, says he is already working to turn his finding into a potential therapy2.
To hunt for factors that could cause adult tissue to make new cardiomyocytes, Kühn and his colleagues isolated heart cells from adult rats and exposed them to proteins already known to prompt fetal tissue to build hearts. Their search identified the well-studied protein neuregulin 1. Kühn's team then turned to mice, simulating heart attacks in dozens of them by tying off a major artery feeding the heart before giving half of them abdominal injections of neuregulin 1 for 12 weeks. After waiting two weeks for the direct effects of neuregulin 1 to wear off, the researchers found that scars resulting from the heart attack were 46% smaller in treated than untreated mice. Additionally, hearts in treated mice displayed less of the weakening cell overgrowth that is typically observed after a heart attack, and they could even pump more blood.
Clone rangers
Clone rangers
Jul 23rd 2009
From The Economist print edition
The technology of cloning is improving step by step
THIS mouse is one of a batch that represent the latest breakthrough in cloning technology. It was created by Zhao Xiaoyang and Li Wei, of the Chinese Academy of Sciences in Beijing, and their colleagues, and was reported this week in Nature. Cloning mice is nothing new, but this one and 26 like it are descended from what are known as induced pluripotent stem cells. These are created from the laboratory-cultured descendants of normal body cells by activating four usually quiescent genes. The result is something similar to an embryonic stem cell, from which it is already known that new, adult mice can be created. The question is, how similar? Dr Zhao and Dr Li have now shown that the answer is, “very similar indeed”.
To make their clones, Dr Zhao and Dr Li injected induced pluripotent cells into early-stage embryos called blastocysts. Normally, the result of doing this is a chimera—an animal that consists of a mixture of cells derived from the injected cell and the blastocyst. That proves the cells are, indeed, pluripotent; in other words, they can turn into a variety of tissues. But to make a true clone a cell needs to be not just pluripotent, but totipotent and thus able to turn into an entire animal.
To show that this, too, is possible, the researchers created a special sort of blastocyst whose cells have double the number of chromosomes found in normal mouse cells. These so-called tetraploid cells can go on to form placental tissue but cannot thrive in the embryo proper. So, if a mouse is born from a stem cell injected into a tetraploid blastocyst, that stem cell must have been totipotent.
Altogether, Dr Zhao and Dr Li created several lines of induced pluripotent stem cells that could produce successful chimeras. Of these, three could also pull off the trick of making a mouse when injected into a tetraploid blastocyst. And one of the 27 mice produced, a male, has also gone on to have a family of its own.
The importance of this work is its demonstration of just how similar to a real embryonic stem cell an induced pluripotent cell is—at least, in mice. If the same technology works in people, it may make the row about using human embryonic stem cells (which involves the destruction of human embryos) redundant. It might also bring closer the day when spare body parts can be grown from, say, skin cells of the person who needs them, eliminating the risk of tissue rejection.
At the moment, such thoughts are science fiction—as are thoughts of turning out human clones from skin cells. But Dr Zhao and Dr Li have taken their field a small step closer to making them fact.
Jul 23rd 2009
From The Economist print edition
The technology of cloning is improving step by step
THIS mouse is one of a batch that represent the latest breakthrough in cloning technology. It was created by Zhao Xiaoyang and Li Wei, of the Chinese Academy of Sciences in Beijing, and their colleagues, and was reported this week in Nature. Cloning mice is nothing new, but this one and 26 like it are descended from what are known as induced pluripotent stem cells. These are created from the laboratory-cultured descendants of normal body cells by activating four usually quiescent genes. The result is something similar to an embryonic stem cell, from which it is already known that new, adult mice can be created. The question is, how similar? Dr Zhao and Dr Li have now shown that the answer is, “very similar indeed”.
To make their clones, Dr Zhao and Dr Li injected induced pluripotent cells into early-stage embryos called blastocysts. Normally, the result of doing this is a chimera—an animal that consists of a mixture of cells derived from the injected cell and the blastocyst. That proves the cells are, indeed, pluripotent; in other words, they can turn into a variety of tissues. But to make a true clone a cell needs to be not just pluripotent, but totipotent and thus able to turn into an entire animal.
To show that this, too, is possible, the researchers created a special sort of blastocyst whose cells have double the number of chromosomes found in normal mouse cells. These so-called tetraploid cells can go on to form placental tissue but cannot thrive in the embryo proper. So, if a mouse is born from a stem cell injected into a tetraploid blastocyst, that stem cell must have been totipotent.
Altogether, Dr Zhao and Dr Li created several lines of induced pluripotent stem cells that could produce successful chimeras. Of these, three could also pull off the trick of making a mouse when injected into a tetraploid blastocyst. And one of the 27 mice produced, a male, has also gone on to have a family of its own.
The importance of this work is its demonstration of just how similar to a real embryonic stem cell an induced pluripotent cell is—at least, in mice. If the same technology works in people, it may make the row about using human embryonic stem cells (which involves the destruction of human embryos) redundant. It might also bring closer the day when spare body parts can be grown from, say, skin cells of the person who needs them, eliminating the risk of tissue rejection.
At the moment, such thoughts are science fiction—as are thoughts of turning out human clones from skin cells. But Dr Zhao and Dr Li have taken their field a small step closer to making them fact.
domingo, 19 de julho de 2009
The calorie delusion: Why food labels are wrong
The calorie delusion: Why food labels are wrong
15 July 2009 by Bijal Trivedi New ScientistMagazine issue 2717. For similar stories, visit the Food and Drink Topic Guide
Can you trust the calorie count of a burger? (Image: Dan Saelinger/Image Bank)
STANDING in line at the coffee shop you feel a little peckish. So what will you choose to keep you going until lunchtime? Will it be that scrumptious-looking chocolate brownie or perhaps a small, nut-based muesli bar. You check the labels: the brownie contains around 250 kilocalories (kcal), while the muesli bar contains more than 300. Surprised at the higher calorie count of what looks like the healthy option, you go for the brownie.
This is the kind of decision that people watching their weight - or even just keeping a casual eye on it - make every day. As long as we keep our calorie intake at around the recommended daily values of 2000 for women and 2500 for men, and get a good mix of nutrients, surely we can eat whatever we like?
This is broadly true; after all, maintaining a healthy weight is largely a matter of balancing calories in and calories out. Yet according to a small band of researchers, using the information on food labels to estimate calorie intake could be a very bad idea. They argue that calorie estimates on food labels are based on flawed and outdated science, and provide misleading information on how much energy your body will actually get from a food. Some food labels may over or underestimate this figure by as much as 25 per cent, enough to foil any diet, and over time even lead to obesity. As the western world's waistlines expand at an alarming rate, they argue, it is time consumers were told the true value of their food.
Calorie counts on food labels around the world are based on a system developed in the late 19th century by American chemist Wilbur Olin Atwater. Atwater calculated the energy content of various foods by burning small samples in controlled conditions and measuring the amount of energy released in the form of heat. To estimate the proportion of this raw energy that was used by the body, Atwater calculated the amount of energy lost as undigested food in faeces, and as chemical energy in the form of urea, ammonia and organic acids found in urine, and then he subtracted these figures from the total. Using this method, Atwater estimated that carbohydrates and protein provide an average of 4 kcal per gram, while fat provides 9 kcal per gram. With a few modifications, these measurements of what is known as metabolisable energy have been the currency of food ever since.
We know these values are approximate. Nutritionists are well aware that our bodies don't incinerate food, they digest it. And digestion - from chewing food to moving it through the gut and chemically breaking it down along the way - takes a different amount of energy for different foods.
15 July 2009 by Bijal Trivedi New ScientistMagazine issue 2717. For similar stories, visit the Food and Drink Topic Guide
Can you trust the calorie count of a burger? (Image: Dan Saelinger/Image Bank)
STANDING in line at the coffee shop you feel a little peckish. So what will you choose to keep you going until lunchtime? Will it be that scrumptious-looking chocolate brownie or perhaps a small, nut-based muesli bar. You check the labels: the brownie contains around 250 kilocalories (kcal), while the muesli bar contains more than 300. Surprised at the higher calorie count of what looks like the healthy option, you go for the brownie.
This is the kind of decision that people watching their weight - or even just keeping a casual eye on it - make every day. As long as we keep our calorie intake at around the recommended daily values of 2000 for women and 2500 for men, and get a good mix of nutrients, surely we can eat whatever we like?
This is broadly true; after all, maintaining a healthy weight is largely a matter of balancing calories in and calories out. Yet according to a small band of researchers, using the information on food labels to estimate calorie intake could be a very bad idea. They argue that calorie estimates on food labels are based on flawed and outdated science, and provide misleading information on how much energy your body will actually get from a food. Some food labels may over or underestimate this figure by as much as 25 per cent, enough to foil any diet, and over time even lead to obesity. As the western world's waistlines expand at an alarming rate, they argue, it is time consumers were told the true value of their food.
Calorie counts on food labels around the world are based on a system developed in the late 19th century by American chemist Wilbur Olin Atwater. Atwater calculated the energy content of various foods by burning small samples in controlled conditions and measuring the amount of energy released in the form of heat. To estimate the proportion of this raw energy that was used by the body, Atwater calculated the amount of energy lost as undigested food in faeces, and as chemical energy in the form of urea, ammonia and organic acids found in urine, and then he subtracted these figures from the total. Using this method, Atwater estimated that carbohydrates and protein provide an average of 4 kcal per gram, while fat provides 9 kcal per gram. With a few modifications, these measurements of what is known as metabolisable energy have been the currency of food ever since.
We know these values are approximate. Nutritionists are well aware that our bodies don't incinerate food, they digest it. And digestion - from chewing food to moving it through the gut and chemically breaking it down along the way - takes a different amount of energy for different foods.
Swine flu death rate estimates 'flawed'
Swine flu death rate estimates 'flawed'
18:04 14 July 2009 by Andy Coghlan New Scientist
For similar stories, visit the Epidemics and Pandemics Topic Guide
Estimates of the proportion of people who will die if infected with swine flu are flawed, say UK researchers.
At present, the estimate of the death rate in the UK and the US is 0.5 per cent, meaning that about five people die for every 1000 people infected. Accurate estimates are needed so that health authorities can best target treatment and vaccination strategies.
But a new analysis suggests three main reasons why current estimates may be wide of the mark.
Hidden infections
The first and main source of uncertainty is the unknown number of infected people, who recover at home without notifying their doctors that they are ill, or receiving a diagnosis.
So although doctors know how many patients are dying of swine flu in hospitals, they don't know what proportion of all cases are life threatening.
But they need both figures to work out the "case-fatality ratio" – calculated by dividing the number of fatal cases by the total number of cases.
"We don't know the denominator," says Azra Ghani, head of a team at Imperial College London tracking development of the epidemic in the UK.
"For that reason, dividing the number of deaths by the number of cases may be flawed," says Ghani's colleague Tini Garske, the lead author of the study exposing gaps in the data.
Delayed surge
A second source of uncertainty is the possibility that deaths from swine flu are being attributed falsely to other causes of death, such as heart attacks or pneumonia from other causes. This would lead to underestimates of the death rate.
Finally, statistics are distorted by a time-lag between the point at which someone is infected and the time they die. This could lead to an apparent surge in deaths which may falsely be interpreted as the virus becoming more deadly through mutation.
Taken together, these factors make it difficult to rely on existing data sources to accurately calculate the death rate or to predict the course of the epidemic.
18:04 14 July 2009 by Andy Coghlan New Scientist
For similar stories, visit the Epidemics and Pandemics Topic Guide
Estimates of the proportion of people who will die if infected with swine flu are flawed, say UK researchers.
At present, the estimate of the death rate in the UK and the US is 0.5 per cent, meaning that about five people die for every 1000 people infected. Accurate estimates are needed so that health authorities can best target treatment and vaccination strategies.
But a new analysis suggests three main reasons why current estimates may be wide of the mark.
Hidden infections
The first and main source of uncertainty is the unknown number of infected people, who recover at home without notifying their doctors that they are ill, or receiving a diagnosis.
So although doctors know how many patients are dying of swine flu in hospitals, they don't know what proportion of all cases are life threatening.
But they need both figures to work out the "case-fatality ratio" – calculated by dividing the number of fatal cases by the total number of cases.
"We don't know the denominator," says Azra Ghani, head of a team at Imperial College London tracking development of the epidemic in the UK.
"For that reason, dividing the number of deaths by the number of cases may be flawed," says Ghani's colleague Tini Garske, the lead author of the study exposing gaps in the data.
Delayed surge
A second source of uncertainty is the possibility that deaths from swine flu are being attributed falsely to other causes of death, such as heart attacks or pneumonia from other causes. This would lead to underestimates of the death rate.
Finally, statistics are distorted by a time-lag between the point at which someone is infected and the time they die. This could lead to an apparent surge in deaths which may falsely be interpreted as the virus becoming more deadly through mutation.
Taken together, these factors make it difficult to rely on existing data sources to accurately calculate the death rate or to predict the course of the epidemic.
domingo, 12 de julho de 2009
Memristor minds: The future of artificial intelligence
Memristor minds: The future of artificial intelligence
08 July 2009 by Justin Mullins New Scientist magazine
EVER had the feeling something is missing? If so, you're in good company. Dmitri Mendeleev did in 1869 when he noticed four gaps in his periodic table. They turned out to be the undiscovered elements scandium, gallium, technetium and germanium. Paul Dirac did in 1929 when he looked deep into the quantum-mechanical equation he had formulated to describe the electron. Besides the electron, he saw something else that looked rather like it, but different. It was only in 1932, when the electron's antimatter sibling, the positron, was sighted in cosmic rays that such a thing was found to exist.
In 1971, Leon Chua had that feeling. A young electronics engineer with a penchant for mathematics at the University of California, Berkeley, he was fascinated by the fact that electronics had no rigorous mathematical foundation. So like any diligent scientist, he set about trying to derive one.
And he found something missing: a fourth basic circuit element besides the standard trio of resistor, capacitor and inductor. Chua dubbed it the "memristor". The only problem was that as far as Chua or anyone else could see, memristors did not actually exist.
Except that they do. Within the past couple of years, memristors have morphed from obscure jargon into one of the hottest properties in physics. They've not only been made, but their unique capabilities might revolutionise consumer electronics. More than that, though, along with completing the jigsaw of electronics, they might solve the puzzle of how nature makes that most delicate and powerful of computers - the brain.
That would be a fitting pay-off for a story which, in its beginnings, is a triumph of pure logic. Back in 1971, Chua was examining the four basic quantities that define an electronic circuit. First, there is electric charge. Then there is the change in that charge over time, better known as current. Currents create magnetic fields, leading to a third variable, magnetic flux, which characterises the field's strength. Finally, magnetic flux varies with time, leading to the quantity we call voltage.
Four interconnected things, mathematics says, can be related in six ways. Charge and current, and magnetic flux and voltage, are connected through their definitions. That's two. Three more associations correspond to the three traditional circuit elements. A resistor is any device that, when you pass current through it, creates a voltage. For a given voltage a capacitor will store a certain amount of charge. Pass a current through an inductor, and you create a magnetic flux. That makes five. Something missing?
Indeed. Where was the device that connected charge and magnetic flux? The short answer was there wasn't one. But there should have been.
Chua set about exploring what this device would do. It was something that no combination of resistors, capacitors and inductors would do. Because moving charges make currents, and changing magnetic fluxes breed voltages, the new device would generate a voltage from a current rather like a resistor, but in a complex, dynamic way. In fact, Chua calculated, it would behave like a resistor that could "remember" what current had flowed through it before (see diagram). Thus the memristor was born.
08 July 2009 by Justin Mullins New Scientist magazine
EVER had the feeling something is missing? If so, you're in good company. Dmitri Mendeleev did in 1869 when he noticed four gaps in his periodic table. They turned out to be the undiscovered elements scandium, gallium, technetium and germanium. Paul Dirac did in 1929 when he looked deep into the quantum-mechanical equation he had formulated to describe the electron. Besides the electron, he saw something else that looked rather like it, but different. It was only in 1932, when the electron's antimatter sibling, the positron, was sighted in cosmic rays that such a thing was found to exist.
In 1971, Leon Chua had that feeling. A young electronics engineer with a penchant for mathematics at the University of California, Berkeley, he was fascinated by the fact that electronics had no rigorous mathematical foundation. So like any diligent scientist, he set about trying to derive one.
And he found something missing: a fourth basic circuit element besides the standard trio of resistor, capacitor and inductor. Chua dubbed it the "memristor". The only problem was that as far as Chua or anyone else could see, memristors did not actually exist.
Except that they do. Within the past couple of years, memristors have morphed from obscure jargon into one of the hottest properties in physics. They've not only been made, but their unique capabilities might revolutionise consumer electronics. More than that, though, along with completing the jigsaw of electronics, they might solve the puzzle of how nature makes that most delicate and powerful of computers - the brain.
That would be a fitting pay-off for a story which, in its beginnings, is a triumph of pure logic. Back in 1971, Chua was examining the four basic quantities that define an electronic circuit. First, there is electric charge. Then there is the change in that charge over time, better known as current. Currents create magnetic fields, leading to a third variable, magnetic flux, which characterises the field's strength. Finally, magnetic flux varies with time, leading to the quantity we call voltage.
Four interconnected things, mathematics says, can be related in six ways. Charge and current, and magnetic flux and voltage, are connected through their definitions. That's two. Three more associations correspond to the three traditional circuit elements. A resistor is any device that, when you pass current through it, creates a voltage. For a given voltage a capacitor will store a certain amount of charge. Pass a current through an inductor, and you create a magnetic flux. That makes five. Something missing?
Indeed. Where was the device that connected charge and magnetic flux? The short answer was there wasn't one. But there should have been.
Chua set about exploring what this device would do. It was something that no combination of resistors, capacitors and inductors would do. Because moving charges make currents, and changing magnetic fluxes breed voltages, the new device would generate a voltage from a current rather like a resistor, but in a complex, dynamic way. In fact, Chua calculated, it would behave like a resistor that could "remember" what current had flowed through it before (see diagram). Thus the memristor was born.
Are we nearly there yet?
Are we nearly there yet?
Jul 10th 2009 From Economist.com
Motorists could learn a thing or two from ants
WITH more Americans than ever economising by driving, rather than flying, to visit friends and family for last weekend’s Independence Day celebrations, the long, winding lines of bumper-to-bumper traffic must have made more than a few turn around and miss the food and fireworks. When stuck in traffic, your correspondent is tempted to compare the competitive nature of motorists (himself included) with the co-operative behaviour of ants. He is intrigued by the way ants manage to avoid traffic jams. The first thing you notice when you watch an ant trail is the way the convoy never comes to a halt, no matter how busy the traffic.
The ants don’t even slow down. As the traffic density builds at junctions where ant trails converge, they continue to maintain the same steady speed as they do on quieter stretches. More intriguing still, they exhibit none of the mutual blocking behaviour found on crowded roads—where motorists prevent others from squeezing in and, in so doing, hinder their own progress as well.
Alamy
There is a world of difference, of course, between ants genetically programmed over millions of years to follow pheromone trails in the best interest of the colony, and motorists constrained to follow the rules of the road, yet determined to demonstrate their free will and to maximise their personal gain. In short, for ants fetching food from a distant source, an efficient transport system is essential for the colony’s survival. For motorists, it is merely a means to get from one place to another while struggling to retain their freedom and individuality.
Yet, despite the differences, your correspondent believes there are lessons motorists can learn from the collective march of ants. For one thing, there is a lot of communication going on between individual ants on a trail, as they broadcast their presence and their intentions chemically to one another. That clearly helps them regulate their distance apart (headway). In so doing, they maintain an optimum speed for a maximum volume of traffic.
One day cars will likewise be able to communicate with one another. It would be preferable if they did so without their owners’ involvement, otherwise there would be even more scope for abuse than at present. However, given the interactive cruise-control systems being incorporated into inter-vehicular communication equipment, it ought to be possible to optimise the space between cars so they can collectively maintain the best speed for a maximum throughput of traffic.
Jul 10th 2009 From Economist.com
Motorists could learn a thing or two from ants
WITH more Americans than ever economising by driving, rather than flying, to visit friends and family for last weekend’s Independence Day celebrations, the long, winding lines of bumper-to-bumper traffic must have made more than a few turn around and miss the food and fireworks. When stuck in traffic, your correspondent is tempted to compare the competitive nature of motorists (himself included) with the co-operative behaviour of ants. He is intrigued by the way ants manage to avoid traffic jams. The first thing you notice when you watch an ant trail is the way the convoy never comes to a halt, no matter how busy the traffic.
The ants don’t even slow down. As the traffic density builds at junctions where ant trails converge, they continue to maintain the same steady speed as they do on quieter stretches. More intriguing still, they exhibit none of the mutual blocking behaviour found on crowded roads—where motorists prevent others from squeezing in and, in so doing, hinder their own progress as well.
Alamy
There is a world of difference, of course, between ants genetically programmed over millions of years to follow pheromone trails in the best interest of the colony, and motorists constrained to follow the rules of the road, yet determined to demonstrate their free will and to maximise their personal gain. In short, for ants fetching food from a distant source, an efficient transport system is essential for the colony’s survival. For motorists, it is merely a means to get from one place to another while struggling to retain their freedom and individuality.
Yet, despite the differences, your correspondent believes there are lessons motorists can learn from the collective march of ants. For one thing, there is a lot of communication going on between individual ants on a trail, as they broadcast their presence and their intentions chemically to one another. That clearly helps them regulate their distance apart (headway). In so doing, they maintain an optimum speed for a maximum volume of traffic.
One day cars will likewise be able to communicate with one another. It would be preferable if they did so without their owners’ involvement, otherwise there would be even more scope for abuse than at present. However, given the interactive cruise-control systems being incorporated into inter-vehicular communication equipment, it ought to be possible to optimise the space between cars so they can collectively maintain the best speed for a maximum throughput of traffic.
Psyched out
Psyched out
Jul 9th 2009 From The Economist print edition
The fewer the competitors, the harder they try
WHAT relationship there is between the number of participants in a competition and the motivation of the competitors has long eluded researchers. Does the presence of a lot of rivals stimulate action or lead someone to give up hope? It is more than an academic question. Or, rather, it is a very academic question indeed, for it may affect the way that examinations are conducted if they are to be a fair test for all.
To investigate the matter two behavioural researchers, Stephen Garcia at the University of Michigan and Avishalom Tor at the University of Haifa in Israel, looked at the results of the SAT university entrance examination in America in 2005. This test generates a score supposedly based on the test-taker’s verbal and analytical prowess.
The two researchers used data on the number of test-takers in each state of the union and the number of test-taking venues in that state to calculate the average number of test-takers per venue in the state in question. They found that test scores fell as the number of people in the examination hall increased. And they discovered that this pattern was also true for the Cognitive Reflection Test, another analytical exam.
These results are intriguing, but lend themselves to more than one explanation. To find out whether they were caused by a psychological effect related to the number of perceived competitors, or were merely a consequence of the greater distraction produced by crowding more people together, Dr Garcia and Dr Tor conducted an experiment. They asked 74 university students to take a timed, easy general-knowledge quiz which they were asked to finish as quickly as possible without compromising accuracy. Each student completed the test alone, but half were told they were competing against ten other people and the other half that they were competing against 100. All were informed that those whose completion times were in the top 20% would receive $5.
The results backed up the psychological hypothesis. Students who believed they were competing against only ten people finished in an average of 28.95 seconds. Those who believed they were competing against 100 averaged 33.15 seconds.
Jul 9th 2009 From The Economist print edition
The fewer the competitors, the harder they try
WHAT relationship there is between the number of participants in a competition and the motivation of the competitors has long eluded researchers. Does the presence of a lot of rivals stimulate action or lead someone to give up hope? It is more than an academic question. Or, rather, it is a very academic question indeed, for it may affect the way that examinations are conducted if they are to be a fair test for all.
To investigate the matter two behavioural researchers, Stephen Garcia at the University of Michigan and Avishalom Tor at the University of Haifa in Israel, looked at the results of the SAT university entrance examination in America in 2005. This test generates a score supposedly based on the test-taker’s verbal and analytical prowess.
The two researchers used data on the number of test-takers in each state of the union and the number of test-taking venues in that state to calculate the average number of test-takers per venue in the state in question. They found that test scores fell as the number of people in the examination hall increased. And they discovered that this pattern was also true for the Cognitive Reflection Test, another analytical exam.
These results are intriguing, but lend themselves to more than one explanation. To find out whether they were caused by a psychological effect related to the number of perceived competitors, or were merely a consequence of the greater distraction produced by crowding more people together, Dr Garcia and Dr Tor conducted an experiment. They asked 74 university students to take a timed, easy general-knowledge quiz which they were asked to finish as quickly as possible without compromising accuracy. Each student completed the test alone, but half were told they were competing against ten other people and the other half that they were competing against 100. All were informed that those whose completion times were in the top 20% would receive $5.
The results backed up the psychological hypothesis. Students who believed they were competing against only ten people finished in an average of 28.95 seconds. Those who believed they were competing against 100 averaged 33.15 seconds.
Sons and mothers
Sons and mothers
Jul 9th 2009
From The Economist print edition
Poor circumstances breed daughters
Panos
THAT mother knows best is no secret. That her reproductive organs also know best may come as more of a surprise. But that is what two evolutionary biologists, Robert Trivers and Dan Willard, hypothesised nearly four decades ago. Boys, they reasoned, will thrive reproductively when they have grown big and strong in resource-rich environments. Otherwise, they will do badly. Girls, by contrast, will do reasonably well across the board and thus have a comparative advantage over their brothers in poorer situations. Parents, meanwhile, have a genetic incentive to see their progeny do well. Give a mother abundant resources, then, and her body should favour sons. Place her in difficult conditions and she should have more daughters.
The Trivers-Willard theory has been tested with success in several species of wild animal. Showing it to be true in people, however, has proved difficult. But a paper just published in Biology Letters by Thomas Pollet of the University of Groningen, in the Netherlands, and his colleagues makes a brave attempt to do so. Dr Pollet tests it by studying polygamous households. As wives are added to such a household, its resources will necessarily be split more ways. Even if they are shared equally, the first wife will have had a head-start on the others—and, life being what it is, she may retain a dominant position.
Much of the world has given up open polygamy, of course (though the discreet sort remains common everywhere). It is, however, still practised in parts of Africa. Dr Pollet and his colleagues therefore turned to Rwanda, and used data gathered in a census of that country taken in 2002.
They found 96,880 married women who reported having children. They classified the marriages in question as either monogamous or polygamous. The wives in polygamous marriages were further classified as either “first”, “second” or “third or lower order”. As the researchers suspected, when all other things were equal mothers in monogamous marriages had most sons: 101 for every 100 daughters. Those who were the first wives of polygamists scored similarly. Wives who were “third or lower order”, though, had only 94 sons for every 100 daughters.
Jul 9th 2009
From The Economist print edition
Poor circumstances breed daughters
Panos
THAT mother knows best is no secret. That her reproductive organs also know best may come as more of a surprise. But that is what two evolutionary biologists, Robert Trivers and Dan Willard, hypothesised nearly four decades ago. Boys, they reasoned, will thrive reproductively when they have grown big and strong in resource-rich environments. Otherwise, they will do badly. Girls, by contrast, will do reasonably well across the board and thus have a comparative advantage over their brothers in poorer situations. Parents, meanwhile, have a genetic incentive to see their progeny do well. Give a mother abundant resources, then, and her body should favour sons. Place her in difficult conditions and she should have more daughters.
The Trivers-Willard theory has been tested with success in several species of wild animal. Showing it to be true in people, however, has proved difficult. But a paper just published in Biology Letters by Thomas Pollet of the University of Groningen, in the Netherlands, and his colleagues makes a brave attempt to do so. Dr Pollet tests it by studying polygamous households. As wives are added to such a household, its resources will necessarily be split more ways. Even if they are shared equally, the first wife will have had a head-start on the others—and, life being what it is, she may retain a dominant position.
Much of the world has given up open polygamy, of course (though the discreet sort remains common everywhere). It is, however, still practised in parts of Africa. Dr Pollet and his colleagues therefore turned to Rwanda, and used data gathered in a census of that country taken in 2002.
They found 96,880 married women who reported having children. They classified the marriages in question as either monogamous or polygamous. The wives in polygamous marriages were further classified as either “first”, “second” or “third or lower order”. As the researchers suspected, when all other things were equal mothers in monogamous marriages had most sons: 101 for every 100 daughters. Those who were the first wives of polygamists scored similarly. Wives who were “third or lower order”, though, had only 94 sons for every 100 daughters.
sábado, 4 de julho de 2009
Local yokels
Local yokels
Jul 1st 2009 From The Economist print edition
Electronic communications may have shrunk, rather than expanded, horizons
THE rise of the internet was supposed to create a global village, in which people would be as likely to have friends in the antipodes as in their own street. Poppycock, of course. But the idea that it might instead have shrunk people’s horizons is truly counter-intuitive. Yet that is what Jacob Goldenberg and Moshe Levy of the Hebrew University in Jerusalem suspect. Their evidence is indirect, and from a strange source—the spread of babies’ names. But it does suggest that something worthy of investigation is going on.
The two researchers’ study of the spread of new names was prompted by their discovery that the relationship between the number of private e-mails sent in America and the distance between sender and recipient falls off far more steeply than they expected. People are overwhelmingly e-mailing others in the same city, rather than those far away.
That says something about human relations, but not how they have changed since e-mail became ubiquitous. So Dr Goldenberg and Dr Levy needed to find something pertinent that bridged the period in question and might thus shed more light on their result. In an inspired piece of lateral thinking, they decided to look at how babies’ names spread.
Jul 1st 2009 From The Economist print edition
Electronic communications may have shrunk, rather than expanded, horizons
THE rise of the internet was supposed to create a global village, in which people would be as likely to have friends in the antipodes as in their own street. Poppycock, of course. But the idea that it might instead have shrunk people’s horizons is truly counter-intuitive. Yet that is what Jacob Goldenberg and Moshe Levy of the Hebrew University in Jerusalem suspect. Their evidence is indirect, and from a strange source—the spread of babies’ names. But it does suggest that something worthy of investigation is going on.
The two researchers’ study of the spread of new names was prompted by their discovery that the relationship between the number of private e-mails sent in America and the distance between sender and recipient falls off far more steeply than they expected. People are overwhelmingly e-mailing others in the same city, rather than those far away.
That says something about human relations, but not how they have changed since e-mail became ubiquitous. So Dr Goldenberg and Dr Levy needed to find something pertinent that bridged the period in question and might thus shed more light on their result. In an inspired piece of lateral thinking, they decided to look at how babies’ names spread.
Survival of the less fit
Survival of the less fit
Jul 3rd 2009
From The Economist print edition
The mystery of Scotland’s shrinking sheep may have been solved
Alamy
Downsizing
ON THE remote island of Hirta, in the St Kilda archipelago beyond the Outer Hebrides, live hundreds of wild Soay sheep. Over the past 20 years biologists studying this primitive breed, which has not changed much since the Bronze Age, have noticed that the sheep are getting smaller. This was a puzzle because, in general, bigger animals are usually much better at surviving the island’s extremely cold winters. The biologists now think that climate change could be involved.
Tim Coulson of Imperial College, London, and his colleagues examined the weights of about 2,000 female sheep that lived on the island in the two decades of their study. They combined this information with detailed histories of individual animals. They found that daughters were, on average, lighter than their mothers had been at the same age. Their legs were shorter, too, suggesting that the breed really was shrinking.
Why is this happening? The researchers, who published their results in the current issue of Science, suspected that it might have something to do with climate change. To explore this they used an index of weather severity called the North Atlantic oscillation. This tracks the difference in air pressure between Iceland and the Azores and, during the winter months, determines the strength of the winds, temperatures and rainfall in the St Kilda archipelago. From this index the researchers concluded that the winters on Hirta are getting shorter and warmer, and that may be because of climate change.
This has two consequences for the sheep. First, they do not need to have such large fat reserves to live off if the winters they face are getting milder. Second, more sheep survive the winter, so lambs face more competition with larger animals for food, so they grow less fast. If the researchers’ explanation is right and climate change is involved in shrinking the sheep of Hirta, it shows how rapidly environmental change can change populations.
Jul 3rd 2009
From The Economist print edition
The mystery of Scotland’s shrinking sheep may have been solved
Alamy
Downsizing
ON THE remote island of Hirta, in the St Kilda archipelago beyond the Outer Hebrides, live hundreds of wild Soay sheep. Over the past 20 years biologists studying this primitive breed, which has not changed much since the Bronze Age, have noticed that the sheep are getting smaller. This was a puzzle because, in general, bigger animals are usually much better at surviving the island’s extremely cold winters. The biologists now think that climate change could be involved.
Tim Coulson of Imperial College, London, and his colleagues examined the weights of about 2,000 female sheep that lived on the island in the two decades of their study. They combined this information with detailed histories of individual animals. They found that daughters were, on average, lighter than their mothers had been at the same age. Their legs were shorter, too, suggesting that the breed really was shrinking.
Why is this happening? The researchers, who published their results in the current issue of Science, suspected that it might have something to do with climate change. To explore this they used an index of weather severity called the North Atlantic oscillation. This tracks the difference in air pressure between Iceland and the Azores and, during the winter months, determines the strength of the winds, temperatures and rainfall in the St Kilda archipelago. From this index the researchers concluded that the winters on Hirta are getting shorter and warmer, and that may be because of climate change.
This has two consequences for the sheep. First, they do not need to have such large fat reserves to live off if the winters they face are getting milder. Second, more sheep survive the winter, so lambs face more competition with larger animals for food, so they grow less fast. If the researchers’ explanation is right and climate change is involved in shrinking the sheep of Hirta, it shows how rapidly environmental change can change populations.
Flights of fancy
Flights of fancy
Jul 3rd 2009
From Economist.com
Why airborne automobiles will never take off
Terrafugia
WHAT is it about “flying cars” that makes otherwise sensible engineers lose touch with reality? Ever since Glenn Curtiss, a seaplane pioneer, racing legend and the Wright brothers’ rival, tried to make a flying car early in the last century, tinkerers have dreamed of having an automobile sprout wings, soar above the traffic, then land and tuck its wings away ready for a short trip into town. Flying cars of one sort or another have dominated the pages of schoolboy comics ever since.
Enthusiasm for flying cars reached a peak in the 1950s when the Ford Motor Company almost started mass-producing one. Studies done at the time showed such a vehicle was technically feasible, was fairly easy to manufacture and had commercial appeal. The markets identified for it included the police, ambulance and other emergency services plus the armed forces and wealthy individuals.
The problems then, as now, were more regulatory than technical or economic. The Federal Aviation Administration (FAA) was aghast at the volume of additional air traffic Ford had in mind. The air-traffic control systems of the day would have been overwhelmed. Ford promptly abandoned the idea, even though its flying car would have been cheaper to build and operate than the helicopters that subsequently took over most of their intended roles.
Since then, a number of diehards and dreamers have laboured on. Some have hitched small cars to paragliders or gyrocopters. Others have attached wings and control surfaces to motorbikes and tricycles. More recently, the trend has been towards designing vehicles that are more like “roadable planes” than “flyable cars”—with wings that fold back or are detached and left at the landing strip for short trips into town.
Then there are those who believe the best—though, technically, the most challenging—way to build a flying car is to adopt a vertical take-off and landing approach. One enthusiast, Canadian-born Paul Moller of Davis, California, has spent an estimated $250m of his own and other people’s money over the past 45 years trying get his fan-powered Skycar off the ground. So far, none of his vertical take-off and landing prototypes has risen much more than a few feet
Jul 3rd 2009
From Economist.com
Why airborne automobiles will never take off
Terrafugia
WHAT is it about “flying cars” that makes otherwise sensible engineers lose touch with reality? Ever since Glenn Curtiss, a seaplane pioneer, racing legend and the Wright brothers’ rival, tried to make a flying car early in the last century, tinkerers have dreamed of having an automobile sprout wings, soar above the traffic, then land and tuck its wings away ready for a short trip into town. Flying cars of one sort or another have dominated the pages of schoolboy comics ever since.
Enthusiasm for flying cars reached a peak in the 1950s when the Ford Motor Company almost started mass-producing one. Studies done at the time showed such a vehicle was technically feasible, was fairly easy to manufacture and had commercial appeal. The markets identified for it included the police, ambulance and other emergency services plus the armed forces and wealthy individuals.
The problems then, as now, were more regulatory than technical or economic. The Federal Aviation Administration (FAA) was aghast at the volume of additional air traffic Ford had in mind. The air-traffic control systems of the day would have been overwhelmed. Ford promptly abandoned the idea, even though its flying car would have been cheaper to build and operate than the helicopters that subsequently took over most of their intended roles.
Since then, a number of diehards and dreamers have laboured on. Some have hitched small cars to paragliders or gyrocopters. Others have attached wings and control surfaces to motorbikes and tricycles. More recently, the trend has been towards designing vehicles that are more like “roadable planes” than “flyable cars”—with wings that fold back or are detached and left at the landing strip for short trips into town.
Then there are those who believe the best—though, technically, the most challenging—way to build a flying car is to adopt a vertical take-off and landing approach. One enthusiast, Canadian-born Paul Moller of Davis, California, has spent an estimated $250m of his own and other people’s money over the past 45 years trying get his fan-powered Skycar off the ground. So far, none of his vertical take-off and landing prototypes has risen much more than a few feet
Plumage power
Plumage power
Jul 2nd 2009 From The Economist print edition
Chicken feathers could provide a high-capacity store
Forget about putting a tiger in your tank
HYDROGEN has long been touted as the future of energy. It is clean, efficient and the most abundant substance in the universe. It can be used to run an internal combustion engine in a car or power one using a fuel cell, with heat and water as the only emissions. But hydrogen is difficult to store because it is the lightest element. Filling a typical fuel tank of 75 litres—about 20 American gallons—with hydrogen at room temperature and pressure will take a hydrogen-powered car only about a kilometre or so. The gas can be compressed to take up less space, but that can be dangerous. It also uses energy, which removes some of the benefits.
Another way to store hydrogen is to put something inside the tank which increases the total internal surface area to which the molecules of the gas can cling. This means more hydrogen can then be packed into a smaller volume. There has been some progress with materials that can do this, including specially engineered carbon nanotubes. But carbon nanotubes are very expensive to make, especially in large quantities. Richard Wool, a chemical engineer at the University of Delaware, estimates the cost of fitting a single car with a tank full of carbon nanotubes to be $5.5m. Other materials might do, but they could still end up costing over $20,000 a car.
Dr Wool and a colleague, Erman Senöz, think they have found a way to bring the price down to only around $200 a car by using chicken feathers. The fibres in feathers are almost entirely composed of keratin, a protein also found in hair and nails. When heated in the absence of oxygen (a process called pyrolysis), keratin forms hollow tubular structures six millionths of a metre across and riddled with microscopic pores, much like carbon nanotubes.
The researchers demonstrated how this can be done at the 13th Annual Green Chemistry and Engineering Conference, held recently in College Park, Maryland. To avoid melting the fibres and depriving them of their desirable structural properties, they first heat-treated the feathers to around 215°C. This strengthened their structure and allowed further heating to 400-450°C. At this point the material becomes more porous, increasing its surface area and its hydrogen-storing capacity.
The substance they created is capable of holding 1.5% of its weight in hydrogen. Since about 4.5kg of the gas is needed to cover 480km (about 300 miles), the typical range of a petrol-powered car, this would translate into a rather large 284-litre tank stuffed with some 300kg of carbonised chicken feathers, according to Mr Senöz. This still falls short of the 6% hydrogen-storage target which has been set by America’s Department of Energy to encourage innovation with alternative fuels. But the researchers think they can improve their material further by making it even more porous. And unlike rival technologies theirs is well on the way to meeting the department’s cost criteria of a hydrogen system that costs $4 per kilowatt hour stored and less than $700 for installing it. Moreover, it could also help with another environmental problem: reducing the mountains of chicken feathers that the poultry industry has to dispose of every year.
Jul 2nd 2009 From The Economist print edition
Chicken feathers could provide a high-capacity store
Forget about putting a tiger in your tank
HYDROGEN has long been touted as the future of energy. It is clean, efficient and the most abundant substance in the universe. It can be used to run an internal combustion engine in a car or power one using a fuel cell, with heat and water as the only emissions. But hydrogen is difficult to store because it is the lightest element. Filling a typical fuel tank of 75 litres—about 20 American gallons—with hydrogen at room temperature and pressure will take a hydrogen-powered car only about a kilometre or so. The gas can be compressed to take up less space, but that can be dangerous. It also uses energy, which removes some of the benefits.
Another way to store hydrogen is to put something inside the tank which increases the total internal surface area to which the molecules of the gas can cling. This means more hydrogen can then be packed into a smaller volume. There has been some progress with materials that can do this, including specially engineered carbon nanotubes. But carbon nanotubes are very expensive to make, especially in large quantities. Richard Wool, a chemical engineer at the University of Delaware, estimates the cost of fitting a single car with a tank full of carbon nanotubes to be $5.5m. Other materials might do, but they could still end up costing over $20,000 a car.
Dr Wool and a colleague, Erman Senöz, think they have found a way to bring the price down to only around $200 a car by using chicken feathers. The fibres in feathers are almost entirely composed of keratin, a protein also found in hair and nails. When heated in the absence of oxygen (a process called pyrolysis), keratin forms hollow tubular structures six millionths of a metre across and riddled with microscopic pores, much like carbon nanotubes.
The researchers demonstrated how this can be done at the 13th Annual Green Chemistry and Engineering Conference, held recently in College Park, Maryland. To avoid melting the fibres and depriving them of their desirable structural properties, they first heat-treated the feathers to around 215°C. This strengthened their structure and allowed further heating to 400-450°C. At this point the material becomes more porous, increasing its surface area and its hydrogen-storing capacity.
The substance they created is capable of holding 1.5% of its weight in hydrogen. Since about 4.5kg of the gas is needed to cover 480km (about 300 miles), the typical range of a petrol-powered car, this would translate into a rather large 284-litre tank stuffed with some 300kg of carbonised chicken feathers, according to Mr Senöz. This still falls short of the 6% hydrogen-storage target which has been set by America’s Department of Energy to encourage innovation with alternative fuels. But the researchers think they can improve their material further by making it even more porous. And unlike rival technologies theirs is well on the way to meeting the department’s cost criteria of a hydrogen system that costs $4 per kilowatt hour stored and less than $700 for installing it. Moreover, it could also help with another environmental problem: reducing the mountains of chicken feathers that the poultry industry has to dispose of every year.
domingo, 28 de junho de 2009
Africa alone could feed the world
Africa alone could feed the world
27 June 2009
Magazine issue 2714.New Scinetist
DOOM-MONGERS have got it wrong - there is enough space in the world to produce the extra food needed to feed a growing population. And contrary to expectation, most of it can be grown in Africa, say two international reports published this week.
The first, projecting 10 years into the future from last year's food crisis, which saw the price of food soar, says that there is plenty of unused, fertile land available to grow more crops.
"Some 1.6 billion hectares could be added to the current 1.4 billion hectares of crop land [in the world], and over half of the additionally available land is found in Africa and Latin America," concludes the report, compiled by the Organization for Economic Cooperation and Development and the UN Food and Agriculture Organization (FAO).
If further evidence were needed, it comes in a second report, launched jointly by the FAO and the World Bank. It concludes that 400 million hectares, straddling(espalhar) 25 African countries, are suitable for farming.
Models for producing new crop land already exist in Thailand, where land originally deemed(acreditado) agriculturally unpromising, due to irrigation problems and infertile soil, has been transformed into a cornucopia by smallholder farmers.
As in Thailand, future success will come by using agriculture to lift Africa's smallholder farmers out of poverty, aided by strong government measures to guarantee their rights to land, say both reports.
27 June 2009
Magazine issue 2714.New Scinetist
DOOM-MONGERS have got it wrong - there is enough space in the world to produce the extra food needed to feed a growing population. And contrary to expectation, most of it can be grown in Africa, say two international reports published this week.
The first, projecting 10 years into the future from last year's food crisis, which saw the price of food soar, says that there is plenty of unused, fertile land available to grow more crops.
"Some 1.6 billion hectares could be added to the current 1.4 billion hectares of crop land [in the world], and over half of the additionally available land is found in Africa and Latin America," concludes the report, compiled by the Organization for Economic Cooperation and Development and the UN Food and Agriculture Organization (FAO).
If further evidence were needed, it comes in a second report, launched jointly by the FAO and the World Bank. It concludes that 400 million hectares, straddling(espalhar) 25 African countries, are suitable for farming.
Models for producing new crop land already exist in Thailand, where land originally deemed(acreditado) agriculturally unpromising, due to irrigation problems and infertile soil, has been transformed into a cornucopia by smallholder farmers.
As in Thailand, future success will come by using agriculture to lift Africa's smallholder farmers out of poverty, aided by strong government measures to guarantee their rights to land, say both reports.
Why we mustn't let malaria defences crumble
Why we mustn't let malaria defences crumble
22 June 2009 by Martin de Smet New Scientist
Our best anti-malaria drug could be rendered useless by the emergence of resistance (Image: Lehtikuva OY/Rex Features)
REPORTS from Cambodia that malaria is developing resistance to artemisinins have set alarm bells ringing. Artemisinins are the best drugs we have to treat malaria, and until recently there have been no reports of resistance.
Containing resistance in Cambodia is an urgent priority. But sadly, the factors that led to it emerging are all too common in countries where malaria is endemic. Unless we stamp them out there is a risk of artemisinin drugs becoming useless.
To prevent the parasite evolving resistance, artemisinins must not be used alone but with a companion drug such as amodiaquine. Combination pills are available to ensure that this happens. But in many countries, including Cambodia, artemisinins are widely available as a monotherapy. Patients are also prescribed co-blister packs, in which the two drugs are packaged together rather than combined in one pill. There is therefore a risk that patients will take only one drug. We clearly need exclusive use of combination therapies and international commitment to subsidise only combination drugs.
There is another problem. In many countries during transmission season, anyone presenting to a clinic with fever is treated as a malaria patient. In fact no more than 70 per cent of these patients will have malaria, and sometimes as few as 30 per cent. The millions treated unnecessarily are a potential source of resistance: if they become infected shortly after treatment, the malaria parasite is exposed to sub-therapeutic doses of drugs still in the bloodstream, which allows resistance to develop. Use of rapid diagnostic tests or microscopy to confirm malaria is therefore imperative.
22 June 2009 by Martin de Smet New Scientist
Our best anti-malaria drug could be rendered useless by the emergence of resistance (Image: Lehtikuva OY/Rex Features)
REPORTS from Cambodia that malaria is developing resistance to artemisinins have set alarm bells ringing. Artemisinins are the best drugs we have to treat malaria, and until recently there have been no reports of resistance.
Containing resistance in Cambodia is an urgent priority. But sadly, the factors that led to it emerging are all too common in countries where malaria is endemic. Unless we stamp them out there is a risk of artemisinin drugs becoming useless.
To prevent the parasite evolving resistance, artemisinins must not be used alone but with a companion drug such as amodiaquine. Combination pills are available to ensure that this happens. But in many countries, including Cambodia, artemisinins are widely available as a monotherapy. Patients are also prescribed co-blister packs, in which the two drugs are packaged together rather than combined in one pill. There is therefore a risk that patients will take only one drug. We clearly need exclusive use of combination therapies and international commitment to subsidise only combination drugs.
There is another problem. In many countries during transmission season, anyone presenting to a clinic with fever is treated as a malaria patient. In fact no more than 70 per cent of these patients will have malaria, and sometimes as few as 30 per cent. The millions treated unnecessarily are a potential source of resistance: if they become infected shortly after treatment, the malaria parasite is exposed to sub-therapeutic doses of drugs still in the bloodstream, which allows resistance to develop. Use of rapid diagnostic tests or microscopy to confirm malaria is therefore imperative.
segunda-feira, 22 de junho de 2009
The connected car
The connected car
Jun 4th 2009
From The Economist print edition
Cars are becoming more connected, both to remote systems for navigation and information, and to each other
Illustration by Allan Sanders
IN “KNIGHT RIDER”, a 1980s television show, Michael Knight fought for justice with the help of KITT, an artificially intelligent Pontiac Trans Am. The pair chatted amiably, with KITT sensing and reacting to nearby objects, navigating and looking up information about Mr Knight’s immediate surroundings and deadly adversaries. KITT could even drive itself. Thirty years on, many of the fantastical Pontiac’s features are becoming reality.
A modern car can have as many as 200 on-board sensors, measuring everything from tyre pressure to windscreen temperature. A high-end Lexus contains 67 microprocessors, and even the world’s cheapest car, the Tata Nano, has a dozen. Voice-driven satellite navigation is routinely used by millions of people. Radar-equipped cruise control allows vehicles to adjust their speed automatically in traffic. Some cars can even park themselves.
Once a purely mechanical device, the car is going digital. “Connected cars”, which sport links to navigation satellites and communications networks—and, before long, directly to other vehicles—could transform driving, preventing motorists from getting lost, stuck in traffic or involved in accidents. And connectivity can improve entertainment and productivity for both driver and passengers—an attractive proposition given that Americans, for example, spend 45 hours a month in their cars on average. There is also scope(oportunidade) for new business models built around connected cars, from dynamic insurance and road pricing to car pooling(transporte de veículos) and location-based advertising. “We can stop looking at a car as one system,” says Rahul Mangharam, an engineer at the University of Pennsylvania, “and look at it as a node(nódulo) in a n
Jun 4th 2009
From The Economist print edition
Cars are becoming more connected, both to remote systems for navigation and information, and to each other
Illustration by Allan Sanders
IN “KNIGHT RIDER”, a 1980s television show, Michael Knight fought for justice with the help of KITT, an artificially intelligent Pontiac Trans Am. The pair chatted amiably, with KITT sensing and reacting to nearby objects, navigating and looking up information about Mr Knight’s immediate surroundings and deadly adversaries. KITT could even drive itself. Thirty years on, many of the fantastical Pontiac’s features are becoming reality.
A modern car can have as many as 200 on-board sensors, measuring everything from tyre pressure to windscreen temperature. A high-end Lexus contains 67 microprocessors, and even the world’s cheapest car, the Tata Nano, has a dozen. Voice-driven satellite navigation is routinely used by millions of people. Radar-equipped cruise control allows vehicles to adjust their speed automatically in traffic. Some cars can even park themselves.
Once a purely mechanical device, the car is going digital. “Connected cars”, which sport links to navigation satellites and communications networks—and, before long, directly to other vehicles—could transform driving, preventing motorists from getting lost, stuck in traffic or involved in accidents. And connectivity can improve entertainment and productivity for both driver and passengers—an attractive proposition given that Americans, for example, spend 45 hours a month in their cars on average. There is also scope(oportunidade) for new business models built around connected cars, from dynamic insurance and road pricing to car pooling(transporte de veículos) and location-based advertising. “We can stop looking at a car as one system,” says Rahul Mangharam, an engineer at the University of Pennsylvania, “and look at it as a node(nódulo) in a n
sexta-feira, 12 de junho de 2009
Get a grip: Truth about fingerprints revealed
Get a grip: Truth about fingerprints revealed
12 June 2009 by Ewen Callaway
The long-held notion that fingerprints marks help us grip more firmly appears to be wrong. Instead, a new study finds that the marks actually reduce the friction between skin and surfaces.
"Because there are all the gaps between the fingerprints, what they do is reduce the contact area with the surface," says Roland Ennos, a biomechanicist at the University of Manchester, UK, who led the study with colleague Peter Warman.
Rather than singe the prints off an unlucky student to compare hands with and without prints, Ennos rigged Warman's fingers to a special device that slides a weighted sheet of Perspex across a finger and measures the resulting frictional force.
Ennos and Warman determined that the amount of friction generated went up as more of the fingerprint was touching the sheet, but not by as much as expected. This indicated that the skin was behaving like rubber, where friction is proportional to the contact area between the two surfaces. With most solids, friction depends on the force of contact between of the surfaces.
Further tests with varying widths of plastic sheet confirmed this behaviour.
Measurements taken from ink marks then revealed that fingerprints actually reduce the area in contact with a surface by about one third, compared with smooth skin. Therefore fingerprints actually reduce friction, Ennis says.
12 June 2009 by Ewen Callaway
The long-held notion that fingerprints marks help us grip more firmly appears to be wrong. Instead, a new study finds that the marks actually reduce the friction between skin and surfaces.
"Because there are all the gaps between the fingerprints, what they do is reduce the contact area with the surface," says Roland Ennos, a biomechanicist at the University of Manchester, UK, who led the study with colleague Peter Warman.
Rather than singe the prints off an unlucky student to compare hands with and without prints, Ennos rigged Warman's fingers to a special device that slides a weighted sheet of Perspex across a finger and measures the resulting frictional force.
Ennos and Warman determined that the amount of friction generated went up as more of the fingerprint was touching the sheet, but not by as much as expected. This indicated that the skin was behaving like rubber, where friction is proportional to the contact area between the two surfaces. With most solids, friction depends on the force of contact between of the surfaces.
Further tests with varying widths of plastic sheet confirmed this behaviour.
Measurements taken from ink marks then revealed that fingerprints actually reduce the area in contact with a surface by about one third, compared with smooth skin. Therefore fingerprints actually reduce friction, Ennis says.
Tantalizing clues to the chemical origins of life
Tantalizing clues to the chemical origins of life
A synthetic molecule can reshuffle itself to match a DNA template.
Katharine Sanderson Published online 12 June 2009 | Nature(**tantalizing=tentador,utópico)
The new molecule can adapt its sequence to a DNA template.Science / AAAS
Chemists in the United States have made an artificial DNA-like molecule that can change its sequence to bind to a DNA template without the help of enzymes. The findings could shed light on how molecules underpinning life were first able to emerge from a chemical soup.
The vexing question of how strands of DNA or RNA might have first formed has led many chemists to try and recreate the situation in the lab, using synthetic molecules that stack together to form DNA-like strands. Now, Reza Ghadiri at the Scripps Research Institute in La Jolla, California, has taken a different tack — coming up with a molecule that can pair up with different sequences of DNA by rearranging its own sequence.
RNA and DNA both have a backbone made from sugars and phosphorous-containing units called phosphates. Each unit of the DNA or RNA strand also contains one of four bases. The sequence of these bases — adenine, thymine, guanine and cytosine in the case of DNA — forms the genetic code.
Scientists trying to make self-replicating systems have constructed long DNA- and RNA-like molecules from small, information-carrying units that stack together, in the same way that DNA stacks together from nucleotide units in nature. The problem with these is that, once assembled, the sequence of bases cannot usually be changed.
Ghadiri, however, tried a different approach, hoping to find a method of anchoring bases reversibly so that they bind to the backbone but can also come off again.
A synthetic molecule can reshuffle itself to match a DNA template.
Katharine Sanderson Published online 12 June 2009 | Nature(**tantalizing=tentador,utópico)
The new molecule can adapt its sequence to a DNA template.Science / AAAS
Chemists in the United States have made an artificial DNA-like molecule that can change its sequence to bind to a DNA template without the help of enzymes. The findings could shed light on how molecules underpinning life were first able to emerge from a chemical soup.
The vexing question of how strands of DNA or RNA might have first formed has led many chemists to try and recreate the situation in the lab, using synthetic molecules that stack together to form DNA-like strands. Now, Reza Ghadiri at the Scripps Research Institute in La Jolla, California, has taken a different tack — coming up with a molecule that can pair up with different sequences of DNA by rearranging its own sequence.
RNA and DNA both have a backbone made from sugars and phosphorous-containing units called phosphates. Each unit of the DNA or RNA strand also contains one of four bases. The sequence of these bases — adenine, thymine, guanine and cytosine in the case of DNA — forms the genetic code.
Scientists trying to make self-replicating systems have constructed long DNA- and RNA-like molecules from small, information-carrying units that stack together, in the same way that DNA stacks together from nucleotide units in nature. The problem with these is that, once assembled, the sequence of bases cannot usually be changed.
Ghadiri, however, tried a different approach, hoping to find a method of anchoring bases reversibly so that they bind to the backbone but can also come off again.
Glimpse of Earth as seen from afar
Glimpse of Earth as seen from afar
Lunar eclipse paints portrait of Earth that could aid hunt for distant habitable planets.
Eric Hand Published online 10 June 2009 | Nature
The rosy glow of a lunar eclipse helped astronomers capture the Earth's transmission spectrum.Daniel Lopez
Astronomers have seen what the Earth's atmosphere might look like from outer space by using the Moon as a giant mirror. Sunlight that bounced back from the Moon carried a fingerprint of the Earth's atmosphere that could help astronomers determine if the extrasolar planets they're finding harbour life.
The astronomers, at Spain's Institute of Astrophysics of the Canary Islands, made their observations on 16 August 2008 during a lunar eclipse — in which the Moon moves into Earth's shadow. Even when the Moon is totally eclipsed by Earth, it is still bathed in a dim red light — from sunlight that has been bent as it passes through the edge of Earth's atmosphere. Using Earth-based telescopes, the astronomers detected some of this light after it bounced back from the Moon, and captured a 'transmission spectrum' of the light that had passed through Earth's atmospheric halo.
Because gases in Earth's atmosphere absorb certain wavelengths of light, the astronomers were able to pick out key biosignatures in the spectrum — gases such as methane and oxygen that are associated with life on Earth. But they were surprised to find signatures that they expected to be too weak to detect: evidence of Earth's protective ionosphere, which absorbs some of the Sun's highest energy photons, and evidence of nitrogen, which makes up the bulk of the atmosphere but is difficult to detect.
"We find that these signatures are actually much stronger than the models predicted," says institute astronomer Enric Pallé, lead author of a study published today in Nature1. "They will be easier to detect on an exosolar planet."
Lunar eclipse paints portrait of Earth that could aid hunt for distant habitable planets.
Eric Hand Published online 10 June 2009 | Nature
The rosy glow of a lunar eclipse helped astronomers capture the Earth's transmission spectrum.Daniel Lopez
Astronomers have seen what the Earth's atmosphere might look like from outer space by using the Moon as a giant mirror. Sunlight that bounced back from the Moon carried a fingerprint of the Earth's atmosphere that could help astronomers determine if the extrasolar planets they're finding harbour life.
The astronomers, at Spain's Institute of Astrophysics of the Canary Islands, made their observations on 16 August 2008 during a lunar eclipse — in which the Moon moves into Earth's shadow. Even when the Moon is totally eclipsed by Earth, it is still bathed in a dim red light — from sunlight that has been bent as it passes through the edge of Earth's atmosphere. Using Earth-based telescopes, the astronomers detected some of this light after it bounced back from the Moon, and captured a 'transmission spectrum' of the light that had passed through Earth's atmospheric halo.
Because gases in Earth's atmosphere absorb certain wavelengths of light, the astronomers were able to pick out key biosignatures in the spectrum — gases such as methane and oxygen that are associated with life on Earth. But they were surprised to find signatures that they expected to be too weak to detect: evidence of Earth's protective ionosphere, which absorbs some of the Sun's highest energy photons, and evidence of nitrogen, which makes up the bulk of the atmosphere but is difficult to detect.
"We find that these signatures are actually much stronger than the models predicted," says institute astronomer Enric Pallé, lead author of a study published today in Nature1. "They will be easier to detect on an exosolar planet."
domingo, 7 de junho de 2009
Preparing for the worst
Preparing for the worst
May 7th 2009 | NEW YORK
From The Economist print edition
Vaccine makers are ill-prepared for an influenza pandemic
MEXICO CITY sprang back to life this week after two weeks of fear and inactivity. Officials shut down most of the economy to halt the spread of a previously unknown strain of the mongrel H1N1 virus, which is comprised of avian, swine and human influenza viruses. The hope is that the outbreak has now peaked.
If so, that will come as a relief to many, as the virus has spread rapidly around the world. On May 6th the World Health Organisation (WHO) reported 822 confirmed cases in Mexico, including 29 deaths. Altogether, 403 cases have been detected in the United States, including at least one death. Dozens of non-lethal cases have been found in 22 other countries. If a cluster of self-sustaining cases in a region outside the Americas is confirmed, the WHO will raise its concern from level five to the top of its six-level scale for global pandemics.
Richard Besser, the acting director of America’s Centres for Disease Control (CDC), said the virus “so far is not looking more severe than a strain that we would see in seasonal flu.” That is not as reassuring as it sounds. An influenza outbreak in 1918 began in a mild way, but returned in a lethal form months later and killed millions. Margaret Chan, the WHO’s boss, cautioned: “it may come back…the world should prepare for it.”
One of the best ways to do so is vaccination. Surveillance systems and antiviral treatments will help contain a disease, but they cannot halt it the way a vaccine could. Such a treatment would have to come from the makers of vaccines for the more ordinary, seasonal strains of flu. Yet despite all the advances in biological science, this industry still relies on capital-intensive, inflexible and old-fashioned technologies, such as producing vaccines from millions of chicken eggs.
May 7th 2009 | NEW YORK
From The Economist print edition
Vaccine makers are ill-prepared for an influenza pandemic
MEXICO CITY sprang back to life this week after two weeks of fear and inactivity. Officials shut down most of the economy to halt the spread of a previously unknown strain of the mongrel H1N1 virus, which is comprised of avian, swine and human influenza viruses. The hope is that the outbreak has now peaked.
If so, that will come as a relief to many, as the virus has spread rapidly around the world. On May 6th the World Health Organisation (WHO) reported 822 confirmed cases in Mexico, including 29 deaths. Altogether, 403 cases have been detected in the United States, including at least one death. Dozens of non-lethal cases have been found in 22 other countries. If a cluster of self-sustaining cases in a region outside the Americas is confirmed, the WHO will raise its concern from level five to the top of its six-level scale for global pandemics.
Richard Besser, the acting director of America’s Centres for Disease Control (CDC), said the virus “so far is not looking more severe than a strain that we would see in seasonal flu.” That is not as reassuring as it sounds. An influenza outbreak in 1918 began in a mild way, but returned in a lethal form months later and killed millions. Margaret Chan, the WHO’s boss, cautioned: “it may come back…the world should prepare for it.”
One of the best ways to do so is vaccination. Surveillance systems and antiviral treatments will help contain a disease, but they cannot halt it the way a vaccine could. Such a treatment would have to come from the makers of vaccines for the more ordinary, seasonal strains of flu. Yet despite all the advances in biological science, this industry still relies on capital-intensive, inflexible and old-fashioned technologies, such as producing vaccines from millions of chicken eggs.
Liar! Liar!
Liar! Liar!
Jun 4th 2009
From The Economist print edition
Scientists are not quite as honest as might be hoped
THAT people, from politicians to priests, cheat and lie is taken for granted by many. But scientists, surely, are above that sort of thing? In the past decade the cases of Hwang Woo-Suk, who falsely reported making human embryonic stem cells by cloning, and Jan Schön, a physicist who claimed astonishing (and fabricated) results in the fields of semiconductors and superconductors, have shown that they certainly are not. However, on these occasions the claims made were so spectacular that they were bound to attract close scrutiny, and thus be exposed eventually. In the cases of Dr Hwang and ex-Dr Schön, the real question for science was not whether it harbours a few megalomaniac fantasists, but why the frauds were not exposed earlier when the papers that made the claims were being reviewed by peers.
Lower-level fraud, however, is much harder to detect: the data point invented or erased to make a graph look better, or to make a result that was not quite statistically significant into that scientific desideratum, the “minimum publishable unit”. How often this sort of thing happens is hard to say. But Daniele Fanelli of the University of Edinburgh thought he would try to find out. His results, published in the Public Library of Science, suggest it is commoner than scientists would like the rest of the world to believe.
Dr Fanelli’s own laboratory was the internet. He hunted down past surveys of scientific honesty and subjected them to what is known as a meta-analysis. This is a technique that allows the results of entire studies, which may not have used the same methods, to be pooled in a statistically meaningful way.
How much this actually matters is moot. Fabricating data is a heinous scientific sin. It steers people down paths that do not lead anywhere and discourages them from following those that do. But cleaning data up has a long tradition. Robert Millikan, the physicist who first measured the charge on the electron, discarded results that did not match his expectations, yet he won a Nobel prize—because he was right. The results of Gregor Mendel, the father of modern genetics, are also suspiciously over-accurate by the tenets of modern statistics. When such practices shade into dishonesty is itself a shady area. Just as everyone thinks himself a better-than-average driver, these results (assuming that they are honest) suggest people are more willing to see sin in others than in themselves. And that, at least, proves something that is sometimes forgotten. Scientists are as human as everyone else.
Jun 4th 2009
From The Economist print edition
Scientists are not quite as honest as might be hoped
THAT people, from politicians to priests, cheat and lie is taken for granted by many. But scientists, surely, are above that sort of thing? In the past decade the cases of Hwang Woo-Suk, who falsely reported making human embryonic stem cells by cloning, and Jan Schön, a physicist who claimed astonishing (and fabricated) results in the fields of semiconductors and superconductors, have shown that they certainly are not. However, on these occasions the claims made were so spectacular that they were bound to attract close scrutiny, and thus be exposed eventually. In the cases of Dr Hwang and ex-Dr Schön, the real question for science was not whether it harbours a few megalomaniac fantasists, but why the frauds were not exposed earlier when the papers that made the claims were being reviewed by peers.
Lower-level fraud, however, is much harder to detect: the data point invented or erased to make a graph look better, or to make a result that was not quite statistically significant into that scientific desideratum, the “minimum publishable unit”. How often this sort of thing happens is hard to say. But Daniele Fanelli of the University of Edinburgh thought he would try to find out. His results, published in the Public Library of Science, suggest it is commoner than scientists would like the rest of the world to believe.
Dr Fanelli’s own laboratory was the internet. He hunted down past surveys of scientific honesty and subjected them to what is known as a meta-analysis. This is a technique that allows the results of entire studies, which may not have used the same methods, to be pooled in a statistically meaningful way.
How much this actually matters is moot. Fabricating data is a heinous scientific sin. It steers people down paths that do not lead anywhere and discourages them from following those that do. But cleaning data up has a long tradition. Robert Millikan, the physicist who first measured the charge on the electron, discarded results that did not match his expectations, yet he won a Nobel prize—because he was right. The results of Gregor Mendel, the father of modern genetics, are also suspiciously over-accurate by the tenets of modern statistics. When such practices shade into dishonesty is itself a shady area. Just as everyone thinks himself a better-than-average driver, these results (assuming that they are honest) suggest people are more willing to see sin in others than in themselves. And that, at least, proves something that is sometimes forgotten. Scientists are as human as everyone else.
Blood and treasure
Blood and treasure
Jun 4th 2009
From The Economist print edition
People are altruistic because they are militaristic, and cultured because they are common. At least that is the message of a couple of new studies
TWO of the oddest things about people are morality and culture. Neither is unique to humans, but Homo sapiens has both in an abundance missing from other species. Indeed, that abundance—of concern for the well-being of others, (even unrelated others), and of finely crafted material objects both useful and ornamental—is seen by many as the mark of man, as what distinguishes humanity from mere beasts.
How these human traits evolved is controversial. But two papers in this week’s Science may throw light on the process. In one, Samuel Bowles of the Santa Fe Institute in New Mexico fleshes out his paradoxical theory that much of human virtue was forged in the crucible of war. Comrades in arms, he believes, become comrades in other things, too.
In the other paper, Mark Thomas and his colleagues at University College, London, suggest that cultural sophistication depends on more than just the evolution of intelligence. It also requires a dense population. If correct, this would explain some puzzling features of the archaeological record that have hitherto been put down to the arbitrary nature of what has survived to the present and what has not.
Dr Bowles’s argument starts in an obscure cranny of evolutionary theory called group selection. This suggests that groups of collaborative individuals will often do better than groups of selfish ones, and thus prosper at their expense. It is therefore no surprise, according to group-selectionists, that individuals might be genetically predisposed to act in self-sacrificial ways.
This good-of-the-group argument was widely believed until the 1960s, when it was subject to rigorous scrutiny and found wanting. The new theory does not pitch groups against groups, or even individuals against individuals, but genes against genes. It does not disallow altruistic behaviour, but requires that this evolve in a way that promotes the interest of a particular gene—for example by helping close relatives who might also harbour the gene in question. The “selfish gene” analysis, so called after a book by Richard Dawkins, makes good-of-the-group outcomes almost impossible to achieve.
Jun 4th 2009
From The Economist print edition
People are altruistic because they are militaristic, and cultured because they are common. At least that is the message of a couple of new studies
TWO of the oddest things about people are morality and culture. Neither is unique to humans, but Homo sapiens has both in an abundance missing from other species. Indeed, that abundance—of concern for the well-being of others, (even unrelated others), and of finely crafted material objects both useful and ornamental—is seen by many as the mark of man, as what distinguishes humanity from mere beasts.
How these human traits evolved is controversial. But two papers in this week’s Science may throw light on the process. In one, Samuel Bowles of the Santa Fe Institute in New Mexico fleshes out his paradoxical theory that much of human virtue was forged in the crucible of war. Comrades in arms, he believes, become comrades in other things, too.
In the other paper, Mark Thomas and his colleagues at University College, London, suggest that cultural sophistication depends on more than just the evolution of intelligence. It also requires a dense population. If correct, this would explain some puzzling features of the archaeological record that have hitherto been put down to the arbitrary nature of what has survived to the present and what has not.
Dr Bowles’s argument starts in an obscure cranny of evolutionary theory called group selection. This suggests that groups of collaborative individuals will often do better than groups of selfish ones, and thus prosper at their expense. It is therefore no surprise, according to group-selectionists, that individuals might be genetically predisposed to act in self-sacrificial ways.
This good-of-the-group argument was widely believed until the 1960s, when it was subject to rigorous scrutiny and found wanting. The new theory does not pitch groups against groups, or even individuals against individuals, but genes against genes. It does not disallow altruistic behaviour, but requires that this evolve in a way that promotes the interest of a particular gene—for example by helping close relatives who might also harbour the gene in question. The “selfish gene” analysis, so called after a book by Richard Dawkins, makes good-of-the-group outcomes almost impossible to achieve.
Jun 4th 2009
From The Economist print edition
People are altruistic because they are militaristic, and cultured because they are common. At least that is the message of a couple of new studies
TWO of the oddest things about people are morality and culture. Neither is unique to humans, but Homo sapiens has both in an abundance missing from other species. Indeed, that abundance—of concern for the well-being of others, (even unrelated others), and of finely crafted material objects both useful and ornamental—is seen by many as the mark of man, as what distinguishes humanity from mere beasts.
How these human traits evolved is controversial. But two papers in this week’s Science may throw light on the process. In one, Samuel Bowles of the Santa Fe Institute in New Mexico fleshes out his paradoxical theory that much of human virtue was forged in the crucible of war. Comrades in arms, he believes, become comrades in other things, too.
In the other paper, Mark Thomas and his colleagues at University College, London, suggest that cultural sophistication depends on more than just the evolution of intelligence. It also requires a dense population. If correct, this would explain some puzzling features of the archaeological record that have hitherto been put down to the arbitrary nature of what has survived to the present and what has not.
Dr Bowles’s argument starts in an obscure cranny of evolutionary theory called group selection. This suggests that groups of collaborative individuals will often do better than groups of selfish ones, and thus prosper at their expense. It is therefore no surprise, according to group-selectionists, that individuals might be genetically predisposed to act in self-sacrificial ways.
This good-of-the-group argument was widely believed until the 1960s, when it was subject to rigorous scrutiny and found wanting. The new theory does not pitch groups against groups, or even individuals against individuals, but genes against genes. It does not disallow altruistic behaviour, but requires that this evolve in a way that promotes the interest of a particular gene—for example by helping close relatives who might also harbour the gene in question. The “selfish gene” analysis, so called after a book by Richard Dawkins, makes good-of-the-group outcomes almost impossible to achieve.
Jun 4th 2009
From The Economist print edition
People are altruistic because they are militaristic, and cultured because they are common. At least that is the message of a couple of new studies
TWO of the oddest things about people are morality and culture. Neither is unique to humans, but Homo sapiens has both in an abundance missing from other species. Indeed, that abundance—of concern for the well-being of others, (even unrelated others), and of finely crafted material objects both useful and ornamental—is seen by many as the mark of man, as what distinguishes humanity from mere beasts.
How these human traits evolved is controversial. But two papers in this week’s Science may throw light on the process. In one, Samuel Bowles of the Santa Fe Institute in New Mexico fleshes out his paradoxical theory that much of human virtue was forged in the crucible of war. Comrades in arms, he believes, become comrades in other things, too.
In the other paper, Mark Thomas and his colleagues at University College, London, suggest that cultural sophistication depends on more than just the evolution of intelligence. It also requires a dense population. If correct, this would explain some puzzling features of the archaeological record that have hitherto been put down to the arbitrary nature of what has survived to the present and what has not.
Dr Bowles’s argument starts in an obscure cranny of evolutionary theory called group selection. This suggests that groups of collaborative individuals will often do better than groups of selfish ones, and thus prosper at their expense. It is therefore no surprise, according to group-selectionists, that individuals might be genetically predisposed to act in self-sacrificial ways.
This good-of-the-group argument was widely believed until the 1960s, when it was subject to rigorous scrutiny and found wanting. The new theory does not pitch groups against groups, or even individuals against individuals, but genes against genes. It does not disallow altruistic behaviour, but requires that this evolve in a way that promotes the interest of a particular gene—for example by helping close relatives who might also harbour the gene in question. The “selfish gene” analysis, so called after a book by Richard Dawkins, makes good-of-the-group outcomes almost impossible to achieve.
The high price of dying in Africa
The high price of dying in Africa
Posted by:
Economist.com | NEW YORK June 05,2009
Categories:
Development economics
I RECENTLY attended a discussion on economic development where an economist from Ghana remarked that a major policy challenge in Africa was funerals. Funerals are major social events in parts of Africa—he claimed it is where people fall in love and relax after a hard week of work. The problem is that they are very expensive. And the high cost of laying someone to rest is undermining efforts to promote saving in African countries.
A new paper by Anne Case and Alicia Menendez considers funeral costs in South Africa. Traditionally, funerals for the very young have been modest affairs and funerals for the old have been covered by insurance. But the AIDS crisis has led to many more deaths among those aged 20 to 34. For this group no custom existed and elaborate and expensive funerals became the norm.
The authors found that, on average, funerals for adults in South Africa now cost 3400 rand ($420). That amounts to 40% of average annual household expenditure. They also found evidence that the financial strain of funerals lowers school attendance among children in the household. None of this is good for South Africa's struggling economy, which contracted at an annualised rate of 6.4% in the first quarter. One hopes the government's post-death policies are bolder than its pre-death efforts.
Posted by:
Economist.com | NEW YORK June 05,2009
Categories:
Development economics
I RECENTLY attended a discussion on economic development where an economist from Ghana remarked that a major policy challenge in Africa was funerals. Funerals are major social events in parts of Africa—he claimed it is where people fall in love and relax after a hard week of work. The problem is that they are very expensive. And the high cost of laying someone to rest is undermining efforts to promote saving in African countries.
A new paper by Anne Case and Alicia Menendez considers funeral costs in South Africa. Traditionally, funerals for the very young have been modest affairs and funerals for the old have been covered by insurance. But the AIDS crisis has led to many more deaths among those aged 20 to 34. For this group no custom existed and elaborate and expensive funerals became the norm.
The authors found that, on average, funerals for adults in South Africa now cost 3400 rand ($420). That amounts to 40% of average annual household expenditure. They also found evidence that the financial strain of funerals lowers school attendance among children in the household. None of this is good for South Africa's struggling economy, which contracted at an annualised rate of 6.4% in the first quarter. One hopes the government's post-death policies are bolder than its pre-death efforts.
domingo, 31 de maio de 2009
Sweet tooth drives tool use in chimpanzees
Sweet tooth drives tool use in chimpanzees
30 May 2009 by Bob Holmes Magazine issue 2710.
Some chimps use multi-purpose tools to forage honey from hives (Image: clix, stock.xchng)
IF YOU'RE impressed that chimps can use tools to hunt or crack nuts, wait till you hear what they do when foraging for honey. Not only do they construct several different tools for the purpose, but they use them sequentially - an achievement approaching the abilities of early Stone Age humans.
A team led by Christophe Boesch of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, studied chimps living in Loango National Park in Gabon. They found that the chimps built and used five different types of tools to help them find beehives and extract honey: thin, straight sticks to probe the ground for buried nests; thick, blunt-ended pounders to break open beehive entrances; thinner lever-like enlargers to break down walls within the hive; collectors with frayed ends to dip honey from the opened hive and bark spoons to scoop it out. Various tools were often found near the same hive, suggesting that the chimps employ them in sequence (Journal of Human Evolution, DOI: 10.1016/j.jhevol.2009.04.001).
A few tools even appeared to have two uses, with enlargers at one end and collectors at the other. This is the first example of a non-human species constructing multipurpose tools.
A few tools had two uses: the first example of a non-human species making multipurpose tools
Some of the tools would require several steps to make, so making and using the entire toolkit implies an impressive ability to plan ahead, compared with, say, cracking a nut with a stone.
Probing for underground hives also requires the chimps to conceive of the existence of unseen objects. The mental skills needed for this and the tasks that follow rival those displayed by humans in the early Stone Age, says Boesch. Indeed, he believes the desire to successfully obtain honey could have been one of the pressures that favoured increased intelligence as humans evolved.
Sweet tooth drives tool use in chimpanzees
30 May 2009 by Bob Holmes Magazine issue
IF YOU'RE impressed that chimps can use tools to hunt or crack nuts, wait till you hear what they do when foraging for honey. Not only do they construct several different tools for the purpose, but they use them sequentially - an achievement approaching the abilities of early Stone Age humans.
A team led by Christophe Boesch of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, studied chimps living in Loango National Park in Gabon. They found that the chimps built and used five different types of tools to help them find beehives and extract honey: thin, straight sticks to probe the ground for buried nests; thick, blunt-ended pounders to break open beehive entrances; thinner lever-like enlargers to break down walls within the hive; collectors with frayed ends to dip honey from the opened hive and bark spoons to scoop it out. Various tools were often found near the same hive, suggesting that the chimps employ them in sequence (Journal of Human Evolution, DOI: 10.1016/j.jhevol.2009.04.001).
A few tools even appeared to have two uses, with enlargers at one end and collectors at the other. This is the first example of a non-human species constructing multipurpose tools.
A few tools had two uses: the first example of a non-human species making multipurpose tools
Some of the tools would require several steps to make, so making and using the entire toolkit implies an impressive ability to plan ahead, compared with, say, cracking a nut with a stone.
Probing for underground hives also requires the chimps to conceive of the existence of unseen objects. The mental skills needed for this and the tasks that follow rival those displayed by humans in the early Stone Age, says Boesch. Indeed, he believes the desire to successfully obtain honey could have been one of the pressures that favoured increased intelligence as humans evolved.
30 May 2009 by Bob Holmes Magazine issue 2710.
Some chimps use multi-purpose tools to forage honey from hives (Image: clix, stock.xchng)
IF YOU'RE impressed that chimps can use tools to hunt or crack nuts, wait till you hear what they do when foraging for honey. Not only do they construct several different tools for the purpose, but they use them sequentially - an achievement approaching the abilities of early Stone Age humans.
A team led by Christophe Boesch of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, studied chimps living in Loango National Park in Gabon. They found that the chimps built and used five different types of tools to help them find beehives and extract honey: thin, straight sticks to probe the ground for buried nests; thick, blunt-ended pounders to break open beehive entrances; thinner lever-like enlargers to break down walls within the hive; collectors with frayed ends to dip honey from the opened hive and bark spoons to scoop it out. Various tools were often found near the same hive, suggesting that the chimps employ them in sequence (Journal of Human Evolution, DOI: 10.1016/j.jhevol.2009.04.001).
A few tools even appeared to have two uses, with enlargers at one end and collectors at the other. This is the first example of a non-human species constructing multipurpose tools.
A few tools had two uses: the first example of a non-human species making multipurpose tools
Some of the tools would require several steps to make, so making and using the entire toolkit implies an impressive ability to plan ahead, compared with, say, cracking a nut with a stone.
Probing for underground hives also requires the chimps to conceive of the existence of unseen objects. The mental skills needed for this and the tasks that follow rival those displayed by humans in the early Stone Age, says Boesch. Indeed, he believes the desire to successfully obtain honey could have been one of the pressures that favoured increased intelligence as humans evolved.
Sweet tooth drives tool use in chimpanzees
30 May 2009 by Bob Holmes Magazine issue
IF YOU'RE impressed that chimps can use tools to hunt or crack nuts, wait till you hear what they do when foraging for honey. Not only do they construct several different tools for the purpose, but they use them sequentially - an achievement approaching the abilities of early Stone Age humans.
A team led by Christophe Boesch of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, studied chimps living in Loango National Park in Gabon. They found that the chimps built and used five different types of tools to help them find beehives and extract honey: thin, straight sticks to probe the ground for buried nests; thick, blunt-ended pounders to break open beehive entrances; thinner lever-like enlargers to break down walls within the hive; collectors with frayed ends to dip honey from the opened hive and bark spoons to scoop it out. Various tools were often found near the same hive, suggesting that the chimps employ them in sequence (Journal of Human Evolution, DOI: 10.1016/j.jhevol.2009.04.001).
A few tools even appeared to have two uses, with enlargers at one end and collectors at the other. This is the first example of a non-human species constructing multipurpose tools.
A few tools had two uses: the first example of a non-human species making multipurpose tools
Some of the tools would require several steps to make, so making and using the entire toolkit implies an impressive ability to plan ahead, compared with, say, cracking a nut with a stone.
Probing for underground hives also requires the chimps to conceive of the existence of unseen objects. The mental skills needed for this and the tasks that follow rival those displayed by humans in the early Stone Age, says Boesch. Indeed, he believes the desire to successfully obtain honey could have been one of the pressures that favoured increased intelligence as humans evolved.
Decoding antiquity: Eight scripts that still can't be read
Decoding antiquity: Eight scripts that still can't be read
27 May 2009 by Andrew Robinson
WRITING is one of the greatest inventions in human history. Perhaps the greatest, since it made history possible. Without writing, there could be no accumulation of knowledge, no historical record, no science - and of course no books, newspapers or internet.
The first true writing we know of is Sumerian cuneiform - consisting mainly of wedge-shaped impressions on clay tablets - which was used more than 5000 years ago in Mesopotamia. Soon afterwards writing appeared in Egypt, and much later in Europe, China and Central America. Civilisations have invented hundreds of different writing systems. Some, such as the one you are reading now, have remained in use, but most have fallen into disuse.
These dead scripts tantalise us. We can see that they are writing, but what do they say?
That is the great challenge of decipherment: to reach deep into the past and hear the voices of the dead. When the Egyptian hieroglyphs were deciphered in 1823, they extended the span of recorded history by around 2000 years and allowed us to read the words of Ramses the Great. The decipherment of the Mayan glyphs revealed that the New World had a sophisticated, literate civilisation at the time of the Roman empire.
So how do you decipher an unknown script? There are two minimum requirements. First, there has to be enough material to work with. Secondly, there must be some link to a known language. It helps enormously if there is a bilingual inscription or identifiable proper names - the Rosetta Stone (see image), for example, is written in both ancient Egyptian and ancient Greek, and also contains the name of the Ptolemy dynasty. If there is no clear link, an attempt must be made to relate the concealed language to a known one.
Many ancient scripts have been deciphered (see "The great decipherments" and The ancient scripts), but some significant ones have yet to be cracked. These fall into three broad categories: a known script writing an unknown language; an unknown script writing a known language; and an unknown script writing an unknown language. The first two categories are more likely to yield to decipherment; the third - which recalls Donald Rumsfeld's infamous "unknown unknowns" - is a much tougher proposition, though this doesn't keep people from trying.
Most of the undeciphered scripts featured here have been partially deciphered, and well-known researchers have claimed that they have deciphered some much more fully. Further progress is possible for most of them, especially if new inscriptions are discovered, which fortunately happens fairly often.
27 May 2009 by Andrew Robinson
WRITING is one of the greatest inventions in human history. Perhaps the greatest, since it made history possible. Without writing, there could be no accumulation of knowledge, no historical record, no science - and of course no books, newspapers or internet.
The first true writing we know of is Sumerian cuneiform - consisting mainly of wedge-shaped impressions on clay tablets - which was used more than 5000 years ago in Mesopotamia. Soon afterwards writing appeared in Egypt, and much later in Europe, China and Central America. Civilisations have invented hundreds of different writing systems. Some, such as the one you are reading now, have remained in use, but most have fallen into disuse.
These dead scripts tantalise us. We can see that they are writing, but what do they say?
That is the great challenge of decipherment: to reach deep into the past and hear the voices of the dead. When the Egyptian hieroglyphs were deciphered in 1823, they extended the span of recorded history by around 2000 years and allowed us to read the words of Ramses the Great. The decipherment of the Mayan glyphs revealed that the New World had a sophisticated, literate civilisation at the time of the Roman empire.
So how do you decipher an unknown script? There are two minimum requirements. First, there has to be enough material to work with. Secondly, there must be some link to a known language. It helps enormously if there is a bilingual inscription or identifiable proper names - the Rosetta Stone (see image), for example, is written in both ancient Egyptian and ancient Greek, and also contains the name of the Ptolemy dynasty. If there is no clear link, an attempt must be made to relate the concealed language to a known one.
Many ancient scripts have been deciphered (see "The great decipherments" and The ancient scripts), but some significant ones have yet to be cracked. These fall into three broad categories: a known script writing an unknown language; an unknown script writing a known language; and an unknown script writing an unknown language. The first two categories are more likely to yield to decipherment; the third - which recalls Donald Rumsfeld's infamous "unknown unknowns" - is a much tougher proposition, though this doesn't keep people from trying.
Most of the undeciphered scripts featured here have been partially deciphered, and well-known researchers have claimed that they have deciphered some much more fully. Further progress is possible for most of them, especially if new inscriptions are discovered, which fortunately happens fairly often.
sábado, 30 de maio de 2009
Stretching Your Mouth Affects What You Hear
Stretching Your Mouth Affects What You Hear
Depending on how a mechanical device pulls and tugs areas around the mouth, the volunteer will hear and interpret speech sounds differently
By Erica Westly Scientific American Magazine - May 28, 2009
Neuroscience textbooks typically portray the five senses as separate entities, but in the real world the senses frequently interact, as anyone who has tried to enjoy dinner with a stuffy nose can attest. Hearing and vision seem similarly connected, the most famous example being the “McGurk effect,” where visual cues, such as moving lips, affect how people hear speech. And now new research shows that touch can influence speech perception, too.
David Ostry, a neuroscientist with co-appointments at McGill University and the New Haven, Conn.–based speech center Haskins Laboratories, has been studying for years the relation between speech and the somatosensory system, the network of receptors in skin and muscle that report information on tactile stimuli to the brain. In his most recent study, published in the Proceedings of the National Academy of Sciences USA, he and two Haskins colleagues found that subjects heard words differently when their mouths were stretched into different positions. The results have implications for neuroscientists studying speech and hearing as well as for therapists looking for new ways to treat speech disorders.
In the study, a specially designed robotic device stretched the mouths of volunteers slightly up, down or backward while they listened to a computer-generated continuum of speech verbalizations that sounded like “head” or “had,” or something in between. When the subjects’ mouths were stretched upward, closer to the position needed to say “head,” they were more likely to hear the sounds as “head,” especially with the more ambiguous output. If the subjects’ mouths were stretched downward, as if to say “had,” they were more likely to hear “had,” even when the sounds being generated were closer to “head.” Stretching subjects’ mouths backward had no effect, implying a position-specific response. Moreover, the timing of the stretch had to match that of the sounds exactly to get an effect: the stretch altered speech perception only when it mimicked realistic vocalizations.
Depending on how a mechanical device pulls and tugs areas around the mouth, the volunteer will hear and interpret speech sounds differently
By Erica Westly Scientific American Magazine - May 28, 2009
Neuroscience textbooks typically portray the five senses as separate entities, but in the real world the senses frequently interact, as anyone who has tried to enjoy dinner with a stuffy nose can attest. Hearing and vision seem similarly connected, the most famous example being the “McGurk effect,” where visual cues, such as moving lips, affect how people hear speech. And now new research shows that touch can influence speech perception, too.
David Ostry, a neuroscientist with co-appointments at McGill University and the New Haven, Conn.–based speech center Haskins Laboratories, has been studying for years the relation between speech and the somatosensory system, the network of receptors in skin and muscle that report information on tactile stimuli to the brain. In his most recent study, published in the Proceedings of the National Academy of Sciences USA, he and two Haskins colleagues found that subjects heard words differently when their mouths were stretched into different positions. The results have implications for neuroscientists studying speech and hearing as well as for therapists looking for new ways to treat speech disorders.
In the study, a specially designed robotic device stretched the mouths of volunteers slightly up, down or backward while they listened to a computer-generated continuum of speech verbalizations that sounded like “head” or “had,” or something in between. When the subjects’ mouths were stretched upward, closer to the position needed to say “head,” they were more likely to hear the sounds as “head,” especially with the more ambiguous output. If the subjects’ mouths were stretched downward, as if to say “had,” they were more likely to hear “had,” even when the sounds being generated were closer to “head.” Stretching subjects’ mouths backward had no effect, implying a position-specific response. Moreover, the timing of the stretch had to match that of the sounds exactly to get an effect: the stretch altered speech perception only when it mimicked realistic vocalizations.
sábado, 23 de maio de 2009
Rethinking the Global Money Supply
Rethinking the Global Money Supply
Less reliance on the U.S. dollar by international reserves would be widely beneficial
By Jeffrey D. Sachs From the June 2009 Scientific American Magazine
The People’s Bank of China jolted the financial world in March with a proposal for a new global monetary arrangement. The proposal initially attracted attention mostly for its signal of China’s rising global economic power, but its content also has much to commend it.
A century ago almost all the world’s currencies were linked to gold and most of the rest to silver. Currencies were readily interchangeable, gold anchored exchange rates and the physical supply of gold stabilized the money supply over the long term.
The gold standard collapsed in the wake of World War I. Wartime financing with unbacked paper currency led to widespread inflation. European nations tried to resume the gold standard in the 1920s, but the gold supply was insufficient and inelastic. A ferocious monetary squeeze and competition across countries for limited gold reserves followed and contributed to the Great Depression. After World War II, nations adopted the dollar-exchange standard. The U.S. dollar was backed by gold at $35 per ounce, while the rest of the world’s currencies were backed by dollars. The global money stock could expand through dollar reserves.
President Richard Nixon delinked the dollar from gold in 1971 (to offset the U.S.’s expansionary monetary policies in the Vietnam era), and major currencies began to float against one another in value. But most global trade and financial transactions remained dollar-denominated, as did most foreign exchange reserves held by the world’s central banks. The exchange rates of many currencies also remained tightly tied to the dollar.
This special role of the dollar in the international monetary system has contributed to the global scale of the current crisis, which is rooted in a combination of overly expansionary monetary policies by the Federal Reserve and lax financial regulations. Easy money fed an unprecedented surge in bank credits, first in the U.S. and then elsewhere, as international banks funded themselves in the U.S. money markets. As bank loans flowed into other economies, many foreign central banks intervened to maintain currency stability with the dollar. The surge in the U.S. money supply was thus matched by a surge in the money supplies of countries linked to the U.S. dollar. The result was a temporary worldwide credit bubble, followed by a wave of loan defaults, falling housing prices, banking losses and a dramatic tightening of bank lending.
China has now proposed that the world move to a more symmetrical monetary system, in which nations peg their currencies to a representative basket of others rather than to the dollar alone. The “special drawing rights” of the International Monetary Fund is such a basket of four currencies (the dollar, pound, yen and euro), although the Chinese rightly suggest that it should be rebased to reflect a broader range of them, including China’s yuan. U.S. monetary policy would accordingly lose its excessive global influence over money supplies and credit conditions. On average, the dollar should depreciate against Asian currencies to encourage more U.S. net exports to Asia. The euro should probably strengthen against the dollar but weaken against Asian currencies.
The U.S. response to the Chinese proposal was revealing. Treasury Secretary Timothy Geithner initially described himself as open to exploring the idea; his candor quickly caused the dollar to weaken in value—which it needs to do for the good of the U.S. economy. That weakening, however, led Geithner to reverse himself within minutes by underscoring that the U.S. dollar would remain the world’s reserve currency for the foreseeable future.
Geithner’s first reaction was right. The Chinese proposal requires study but seems consistent with the long-term shift to a more balanced world economy in which the U.S. plays a monetary role more coequal with Europe and Asia. No change of global monetary system will happen abruptly, but the changes ahead are not under the sole control of the U.S. We will probably move over time to a world of greater monetary cooperation within Asia, a rising role for the Chinese yuan, and greater symmetry in overall world monetary and financial relations
Less reliance on the U.S. dollar by international reserves would be widely beneficial
By Jeffrey D. Sachs From the June 2009 Scientific American Magazine
The People’s Bank of China jolted the financial world in March with a proposal for a new global monetary arrangement. The proposal initially attracted attention mostly for its signal of China’s rising global economic power, but its content also has much to commend it.
A century ago almost all the world’s currencies were linked to gold and most of the rest to silver. Currencies were readily interchangeable, gold anchored exchange rates and the physical supply of gold stabilized the money supply over the long term.
The gold standard collapsed in the wake of World War I. Wartime financing with unbacked paper currency led to widespread inflation. European nations tried to resume the gold standard in the 1920s, but the gold supply was insufficient and inelastic. A ferocious monetary squeeze and competition across countries for limited gold reserves followed and contributed to the Great Depression. After World War II, nations adopted the dollar-exchange standard. The U.S. dollar was backed by gold at $35 per ounce, while the rest of the world’s currencies were backed by dollars. The global money stock could expand through dollar reserves.
President Richard Nixon delinked the dollar from gold in 1971 (to offset the U.S.’s expansionary monetary policies in the Vietnam era), and major currencies began to float against one another in value. But most global trade and financial transactions remained dollar-denominated, as did most foreign exchange reserves held by the world’s central banks. The exchange rates of many currencies also remained tightly tied to the dollar.
This special role of the dollar in the international monetary system has contributed to the global scale of the current crisis, which is rooted in a combination of overly expansionary monetary policies by the Federal Reserve and lax financial regulations. Easy money fed an unprecedented surge in bank credits, first in the U.S. and then elsewhere, as international banks funded themselves in the U.S. money markets. As bank loans flowed into other economies, many foreign central banks intervened to maintain currency stability with the dollar. The surge in the U.S. money supply was thus matched by a surge in the money supplies of countries linked to the U.S. dollar. The result was a temporary worldwide credit bubble, followed by a wave of loan defaults, falling housing prices, banking losses and a dramatic tightening of bank lending.
China has now proposed that the world move to a more symmetrical monetary system, in which nations peg their currencies to a representative basket of others rather than to the dollar alone. The “special drawing rights” of the International Monetary Fund is such a basket of four currencies (the dollar, pound, yen and euro), although the Chinese rightly suggest that it should be rebased to reflect a broader range of them, including China’s yuan. U.S. monetary policy would accordingly lose its excessive global influence over money supplies and credit conditions. On average, the dollar should depreciate against Asian currencies to encourage more U.S. net exports to Asia. The euro should probably strengthen against the dollar but weaken against Asian currencies.
The U.S. response to the Chinese proposal was revealing. Treasury Secretary Timothy Geithner initially described himself as open to exploring the idea; his candor quickly caused the dollar to weaken in value—which it needs to do for the good of the U.S. economy. That weakening, however, led Geithner to reverse himself within minutes by underscoring that the U.S. dollar would remain the world’s reserve currency for the foreseeable future.
Geithner’s first reaction was right. The Chinese proposal requires study but seems consistent with the long-term shift to a more balanced world economy in which the U.S. plays a monetary role more coequal with Europe and Asia. No change of global monetary system will happen abruptly, but the changes ahead are not under the sole control of the U.S. We will probably move over time to a world of greater monetary cooperation within Asia, a rising role for the Chinese yuan, and greater symmetry in overall world monetary and financial relations
Old seasonal flu antibodies target swine flu virus
Old seasonal flu antibodies target swine flu virus
Lab results could explain why young patients are hardest hit by current H1N1 strain.
Heidi Ledford Published online 21 May 2009 | Nature
Antibodies against some seasonal flu strains from prior years may be active against the new H1N1 swine flu currently circulating the globe, a recent study reports. The findings suggest an explanation for why swine flu appears to infect the young more often than the elderly, who are normally more susceptible to seasonal flu viruses.
Only 1% of swine flu cases in the United States are in people over the age of 65.CDC
The study, published today in the Morbidity and Mortality Weekly Report, analyzed blood samples taken from 359 participants in flu vaccine studies conducted from 2005 to 2009. 33% of the samples from people over 60 years old had antibodies that reacted with the swine flu virus, as compared to 6%-9% of the samples from people aged 18–64 years, and none of the samples taken from children 1.
The results match the apparent current epidemiology of swine flu infection, says Anne Schuchat, interim deputy director for the Science and Public Health Program at the Centers for Disease Control and Prevention (CDC) in Atlanta. Most cases of swine flu have occurred in people who are under 60 years old, and only 1% of confirmed swine flu infections in the United States were in patients over the age of 65.
Nevertheless, the results should be interpreted with caution, Schuchat urged in a press briefing today. Researchers have shown that the antibodies react with the virus in test-tube assays, but they have not yet shown that the antibodies can fend off the virus in animals or people. "Whether this particular assay will pan out over time as predictive of clinical protection, we can't say," Schuchat said.
Lab results could explain why young patients are hardest hit by current H1N1 strain.
Heidi Ledford Published online 21 May 2009 | Nature
Antibodies against some seasonal flu strains from prior years may be active against the new H1N1 swine flu currently circulating the globe, a recent study reports. The findings suggest an explanation for why swine flu appears to infect the young more often than the elderly, who are normally more susceptible to seasonal flu viruses.
Only 1% of swine flu cases in the United States are in people over the age of 65.CDC
The study, published today in the Morbidity and Mortality Weekly Report, analyzed blood samples taken from 359 participants in flu vaccine studies conducted from 2005 to 2009. 33% of the samples from people over 60 years old had antibodies that reacted with the swine flu virus, as compared to 6%-9% of the samples from people aged 18–64 years, and none of the samples taken from children 1.
The results match the apparent current epidemiology of swine flu infection, says Anne Schuchat, interim deputy director for the Science and Public Health Program at the Centers for Disease Control and Prevention (CDC) in Atlanta. Most cases of swine flu have occurred in people who are under 60 years old, and only 1% of confirmed swine flu infections in the United States were in patients over the age of 65.
Nevertheless, the results should be interpreted with caution, Schuchat urged in a press briefing today. Researchers have shown that the antibodies react with the virus in test-tube assays, but they have not yet shown that the antibodies can fend off the virus in animals or people. "Whether this particular assay will pan out over time as predictive of clinical protection, we can't say," Schuchat said.
Lab results could explain why young patients are hardest hit by current H1N1 strain.
Heidi Ledford Published online 21 May 2009 | Nature
Antibodies against some seasonal flu strains from prior years may be active against the new H1N1 swine flu currently circulating the globe, a recent study reports. The findings suggest an explanation for why swine flu appears to infect the young more often than the elderly, who are normally more susceptible to seasonal flu viruses.
Only 1% of swine flu cases in the United States are in people over the age of 65.CDC
The study, published today in the Morbidity and Mortality Weekly Report, analyzed blood samples taken from 359 participants in flu vaccine studies conducted from 2005 to 2009. 33% of the samples from people over 60 years old had antibodies that reacted with the swine flu virus, as compared to 6%-9% of the samples from people aged 18–64 years, and none of the samples taken from children 1.
The results match the apparent current epidemiology of swine flu infection, says Anne Schuchat, interim deputy director for the Science and Public Health Program at the Centers for Disease Control and Prevention (CDC) in Atlanta. Most cases of swine flu have occurred in people who are under 60 years old, and only 1% of confirmed swine flu infections in the United States were in patients over the age of 65.
Nevertheless, the results should be interpreted with caution, Schuchat urged in a press briefing today. Researchers have shown that the antibodies react with the virus in test-tube assays, but they have not yet shown that the antibodies can fend off the virus in animals or people. "Whether this particular assay will pan out over time as predictive of clinical protection, we can't say," Schuchat said.
Lab results could explain why young patients are hardest hit by current H1N1 strain.
Heidi Ledford Published online 21 May 2009 | Nature
Antibodies against some seasonal flu strains from prior years may be active against the new H1N1 swine flu currently circulating the globe, a recent study reports. The findings suggest an explanation for why swine flu appears to infect the young more often than the elderly, who are normally more susceptible to seasonal flu viruses.
Only 1% of swine flu cases in the United States are in people over the age of 65.CDC
The study, published today in the Morbidity and Mortality Weekly Report, analyzed blood samples taken from 359 participants in flu vaccine studies conducted from 2005 to 2009. 33% of the samples from people over 60 years old had antibodies that reacted with the swine flu virus, as compared to 6%-9% of the samples from people aged 18–64 years, and none of the samples taken from children 1.
The results match the apparent current epidemiology of swine flu infection, says Anne Schuchat, interim deputy director for the Science and Public Health Program at the Centers for Disease Control and Prevention (CDC) in Atlanta. Most cases of swine flu have occurred in people who are under 60 years old, and only 1% of confirmed swine flu infections in the United States were in patients over the age of 65.
Nevertheless, the results should be interpreted with caution, Schuchat urged in a press briefing today. Researchers have shown that the antibodies react with the virus in test-tube assays, but they have not yet shown that the antibodies can fend off the virus in animals or people. "Whether this particular assay will pan out over time as predictive of clinical protection, we can't say," Schuchat said.
sexta-feira, 22 de maio de 2009
Adaptor die
Adaptor die
Mar 5th 2009
From The Economist print edition
Consumer electronics: A new push is under way to let mobile
IF THE father of electromagnetism, Michael Faraday, could be transported into the 21st century, he would no doubt be awestruck by the iPhone. After five hours of tapping its touch-screen to browse the internet, make calls, play games and determine his location via satellite-positioning, he might also find himself a little puzzled. Why, with all the advances in technology and communications, would such a sophisticated device still need to be plugged in to be recharged? If phone calls and web pages can be beamed through the air to portable devices, then why not electrical power, too? It is a question many consumers and device manufacturers have been asking themselves for some time—and one that both new and established technology companies are now hoping to answer.
To seasoned observers of the electronics industry, the promise of wireless recharging sounds depressingly familiar. In 2004 Splashpower, a British technology firm, was citing “very strong” interest from consumer-electronics firms for its wireless charging pad. Based on the principle of electromagnetic induction that Faraday had discovered in the 19th century, the company’s “Splashpad” contained a coil that generated a magnetic field when a current flowed through it. When a mobile device containing a corresponding coil was brought near the pad, the process was reversed as the magnetic field generated a current in the second coil, charging the device’s battery without the use of wires. Unfortunately, although Faraday’s principles of electromagnetic induction have stood the test of time, Splashpower has not—it was declared bankrupt last year without having launched a single product.
Thanks to its simplicity and scalability, electromagnetic induction is still the technology of choice among many of the remaining companies in the wireless-charging arena. But, as Splashpower found, turning the theory into profitable practice is not straightforward. One of the main difficulties for companies has been persuading manufacturers to incorporate charging modules into their devices. But lately there have been some promising developments.
Mar 5th 2009
From The Economist print edition
Consumer electronics: A new push is under way to let mobile
IF THE father of electromagnetism, Michael Faraday, could be transported into the 21st century, he would no doubt be awestruck by the iPhone. After five hours of tapping its touch-screen to browse the internet, make calls, play games and determine his location via satellite-positioning, he might also find himself a little puzzled. Why, with all the advances in technology and communications, would such a sophisticated device still need to be plugged in to be recharged? If phone calls and web pages can be beamed through the air to portable devices, then why not electrical power, too? It is a question many consumers and device manufacturers have been asking themselves for some time—and one that both new and established technology companies are now hoping to answer.
To seasoned observers of the electronics industry, the promise of wireless recharging sounds depressingly familiar. In 2004 Splashpower, a British technology firm, was citing “very strong” interest from consumer-electronics firms for its wireless charging pad. Based on the principle of electromagnetic induction that Faraday had discovered in the 19th century, the company’s “Splashpad” contained a coil that generated a magnetic field when a current flowed through it. When a mobile device containing a corresponding coil was brought near the pad, the process was reversed as the magnetic field generated a current in the second coil, charging the device’s battery without the use of wires. Unfortunately, although Faraday’s principles of electromagnetic induction have stood the test of time, Splashpower has not—it was declared bankrupt last year without having launched a single product.
Thanks to its simplicity and scalability, electromagnetic induction is still the technology of choice among many of the remaining companies in the wireless-charging arena. But, as Splashpower found, turning the theory into profitable practice is not straightforward. One of the main difficulties for companies has been persuading manufacturers to incorporate charging modules into their devices. But lately there have been some promising developments.
domingo, 10 de maio de 2009
Suffering for science
Suffering for science
May 7th 2009
From The Economist print edition
Europe votes for better regulation of animal experiments
FIFTY years ago, William Russell, a classics scholar, and Rex Burch, a microbiologist, outlined how the use of animals in scientific research could be made more humane. They wanted scientists to restrict the use of animals, to refine their experiments to minimise distress and to replace testing on animals with alternative techniques. Although the “3Rs” have become a guiding principle, the number of animals used today remains far higher than Russell and Burch would have accepted. Finally, that may be changing. On May 5th the European Parliament voted to update the rules on the use of animals in research.
Some 12m animals are used in scientific procedures each year in Europe. Most are mice and rats. The European directive on how such animals should be treated dates from 1986, long before research led to the breeding of the first creatures that carried the genes of another species. Some countries have more restrictions than others. Britain, for example, uses far fewer primates in scientific research than does France. The European Commission said in November 2008 that it wanted to update the rules to better protect laboratory animals throughout Europe. It received hundreds of amendments, but has adopted few of them.
In particular, the politicians decided against an outright ban on the use of great apes. Instead they voted to allow such experiments only when they are intended to conserve the number of chimpanzees, bonobos, gorillas and orang-utans, or when using these species becomes essential to tackling a disease that threatens people. In practice, no great apes have been used in Europe for years and there are no breeding colonies from which to take them. In America, chimpanzees are being used to develop a vaccine for hepatitis C because they are the only creatures, other than humans, to be afflicted by the disease.
Another proposal was to ban the use of primates caught in the wild. Scientists prefer to work with the offspring of animals raised in laboratories because knowledge of the creatures’ complete medical history makes them more dependable.All experiments will be classified according to the degree of pain and distress they cause. If mild or moderate, animals can be used again. Those that experience severe pain will be killed. The legislation would allow mild procedures to be approved by an employer. But those causing moderate or severe pain would need the permission of a national authority.
May 7th 2009
From The Economist print edition
Europe votes for better regulation of animal experiments
FIFTY years ago, William Russell, a classics scholar, and Rex Burch, a microbiologist, outlined how the use of animals in scientific research could be made more humane. They wanted scientists to restrict the use of animals, to refine their experiments to minimise distress and to replace testing on animals with alternative techniques. Although the “3Rs” have become a guiding principle, the number of animals used today remains far higher than Russell and Burch would have accepted. Finally, that may be changing. On May 5th the European Parliament voted to update the rules on the use of animals in research.
Some 12m animals are used in scientific procedures each year in Europe. Most are mice and rats. The European directive on how such animals should be treated dates from 1986, long before research led to the breeding of the first creatures that carried the genes of another species. Some countries have more restrictions than others. Britain, for example, uses far fewer primates in scientific research than does France. The European Commission said in November 2008 that it wanted to update the rules to better protect laboratory animals throughout Europe. It received hundreds of amendments, but has adopted few of them.
In particular, the politicians decided against an outright ban on the use of great apes. Instead they voted to allow such experiments only when they are intended to conserve the number of chimpanzees, bonobos, gorillas and orang-utans, or when using these species becomes essential to tackling a disease that threatens people. In practice, no great apes have been used in Europe for years and there are no breeding colonies from which to take them. In America, chimpanzees are being used to develop a vaccine for hepatitis C because they are the only creatures, other than humans, to be afflicted by the disease.
Another proposal was to ban the use of primates caught in the wild. Scientists prefer to work with the offspring of animals raised in laboratories because knowledge of the creatures’ complete medical history makes them more dependable.All experiments will be classified according to the degree of pain and distress they cause. If mild or moderate, animals can be used again. Those that experience severe pain will be killed. The legislation would allow mild procedures to be approved by an employer. But those causing moderate or severe pain would need the permission of a national authority.
The sound of silence
The sound of silence
May 7th 2009
From The Economist print edition
Sound generators will make electric and hybrid cars safer
WHEN cars run on electric power they not only save fuel and cut emissions but also run more quietly. Ordinarily, people might welcome quieter cars on the roads. However, as the use of hybrid and electric vehicles grows, a new concern is growing too: pedestrians and cyclists find it hard to hear them coming, especially when the cars are moving slowly through a busy town or manoeuvring in a car park. Some drivers say that when their cars are in electric mode people are more likely to step out in front of them. The solution, many now believe, is to fit electric and hybrid cars with external sound systems.
A bill going through the American Congress wants to establish a minimum level of sound for vehicles that are not using an internal-combustion engine, so that blind people and other pedestrians can hear them coming. The bill’s proponents also want that audible alert to be one that will help people judge the direction and speed of the vehicle. A similar idea is being explored by the European Commission.
Although there is little data on accidents, the latest research suggests there is cause for concern. Vehicles operating in electric mode can be particularly hard to hear below 20mph (32kph), according to experiments by Lawrence Rosenblum and his colleagues at the University of California, Riverside. Above that speed the sound of the tyres and of air flowing over the vehicle start to make it more audible.
The researchers made sophisticated recordings of Toyota Prius hybrids running on electric power and petrol-engined cars approaching at 5mph from different directions. These were played to a group of subjects wearing headphones. The subjects were asked to press one of two buttons to identify which way the vehicle was coming from as quickly and accurately as possible. As expected, they could determine the direction of the petrol-engined cars much faster. When natural background sounds, like the engine tickover of a parked car, were added, the hybrids’ direction sometimes could not be detected until they were perilously close. Both sighted and blind subjects gave similar results.
May 7th 2009
From The Economist print edition
Sound generators will make electric and hybrid cars safer
WHEN cars run on electric power they not only save fuel and cut emissions but also run more quietly. Ordinarily, people might welcome quieter cars on the roads. However, as the use of hybrid and electric vehicles grows, a new concern is growing too: pedestrians and cyclists find it hard to hear them coming, especially when the cars are moving slowly through a busy town or manoeuvring in a car park. Some drivers say that when their cars are in electric mode people are more likely to step out in front of them. The solution, many now believe, is to fit electric and hybrid cars with external sound systems.
A bill going through the American Congress wants to establish a minimum level of sound for vehicles that are not using an internal-combustion engine, so that blind people and other pedestrians can hear them coming. The bill’s proponents also want that audible alert to be one that will help people judge the direction and speed of the vehicle. A similar idea is being explored by the European Commission.
Although there is little data on accidents, the latest research suggests there is cause for concern. Vehicles operating in electric mode can be particularly hard to hear below 20mph (32kph), according to experiments by Lawrence Rosenblum and his colleagues at the University of California, Riverside. Above that speed the sound of the tyres and of air flowing over the vehicle start to make it more audible.
The researchers made sophisticated recordings of Toyota Prius hybrids running on electric power and petrol-engined cars approaching at 5mph from different directions. These were played to a group of subjects wearing headphones. The subjects were asked to press one of two buttons to identify which way the vehicle was coming from as quickly and accurately as possible. As expected, they could determine the direction of the petrol-engined cars much faster. When natural background sounds, like the engine tickover of a parked car, were added, the hybrids’ direction sometimes could not be detected until they were perilously close. Both sighted and blind subjects gave similar results.
What a waste
What a waste
May 7th 2009 | CAIRO
From The Economist print edition
Is it wise to kill the capital’s rubbish-ridding pigs?
IN A city not much noted for efficiency, Cairo’s traditional rubbish collectors, or Zabbaleen, have long been something of a paragon. While failing to keep Egypt’s teeming capital very clean, the Zabbaleen, nearly all of them members of Egypt’s 6m-plus Coptic Christian minority, do an excellent job of processing waste(lixo). Trucking refuse to the half-dozen rag-picking settlements that ring the city, they carefully sift out(separar) recyclable glass, paper and plastic. The rest is fed to pigs.
But in response to the global threat of swine flu, Egypt’s government has decreed (decretado)that the pigs, perhaps 250,000 of them, must go. Teams of surgical-mask-wearing pig-hunters were met at first with a barrage of rocks, bottles and manure(esterco) hurled(jogar violentamente) by the angry Zabbaleen. Now, backed by riot police and promising compensation, they are systematically hauling(lever) the beasts off for slaughter(abate, extermínio), a process expected to take several months.
With no cases of swine flu reported in Egypt to date, officials from both the UN and the World Health Organisation have condemned Egypt’s porcicide as a drastic overreaction. Some disgruntled(mal humorado) Copts, who have long complained of petty(pequena,discriminatória) discrimination and fear the influence of Islamist groups such as the Muslim Brotherhood, say the move unfairly(injusto) targets(alvos) them. Others, noting that Egypt’s minister of health consulted Coptic clergy before announcing the cull(abate), see it as a plot by wealthy businessmen to uproot (arrrancar pela raiz, extirpar, remover)the Zabbaleen and seize (tomar, arrancar)their valuable land on the edge(limite) of the city. Still more rumours explain the government’s swinophobia as a ploy(blefe) to distract attention from other failings, such as not paying a promised salary bonus.
Yet most of the 80m-odd Egyptians seem relieved. While Muslims shun(afastar) pigs as ritually unclean, many Copts also fear them as disease-carriers, with panic over swine flu heightened as Egypt has suffered at least 26 deaths from avian flu since 2006, the most in any country outside Asia. Besides, the crowded pig pens(chiqueiro), surrounded by mounds(montes) of self-combusting biodegradable slime(lama, sujeira) and hemmed in(rodeado) by dense human settlement, are a stinky(fedorento) eyesore(algo desprezível). But the question no one seems to ask is, if pigs are no longer there to munch away(devorar) at them, where will Cairo’s giant piles of leftovers(sobras) go?
May 7th 2009 | CAIRO
From The Economist print edition
Is it wise to kill the capital’s rubbish-ridding pigs?
IN A city not much noted for efficiency, Cairo’s traditional rubbish collectors, or Zabbaleen, have long been something of a paragon. While failing to keep Egypt’s teeming capital very clean, the Zabbaleen, nearly all of them members of Egypt’s 6m-plus Coptic Christian minority, do an excellent job of processing waste(lixo). Trucking refuse to the half-dozen rag-picking settlements that ring the city, they carefully sift out(separar) recyclable glass, paper and plastic. The rest is fed to pigs.
But in response to the global threat of swine flu, Egypt’s government has decreed (decretado)that the pigs, perhaps 250,000 of them, must go. Teams of surgical-mask-wearing pig-hunters were met at first with a barrage of rocks, bottles and manure(esterco) hurled(jogar violentamente) by the angry Zabbaleen. Now, backed by riot police and promising compensation, they are systematically hauling(lever) the beasts off for slaughter(abate, extermínio), a process expected to take several months.
With no cases of swine flu reported in Egypt to date, officials from both the UN and the World Health Organisation have condemned Egypt’s porcicide as a drastic overreaction. Some disgruntled(mal humorado) Copts, who have long complained of petty(pequena,discriminatória) discrimination and fear the influence of Islamist groups such as the Muslim Brotherhood, say the move unfairly(injusto) targets(alvos) them. Others, noting that Egypt’s minister of health consulted Coptic clergy before announcing the cull(abate), see it as a plot by wealthy businessmen to uproot (arrrancar pela raiz, extirpar, remover)the Zabbaleen and seize (tomar, arrancar)their valuable land on the edge(limite) of the city. Still more rumours explain the government’s swinophobia as a ploy(blefe) to distract attention from other failings, such as not paying a promised salary bonus.
Yet most of the 80m-odd Egyptians seem relieved. While Muslims shun(afastar) pigs as ritually unclean, many Copts also fear them as disease-carriers, with panic over swine flu heightened as Egypt has suffered at least 26 deaths from avian flu since 2006, the most in any country outside Asia. Besides, the crowded pig pens(chiqueiro), surrounded by mounds(montes) of self-combusting biodegradable slime(lama, sujeira) and hemmed in(rodeado) by dense human settlement, are a stinky(fedorento) eyesore(algo desprezível). But the question no one seems to ask is, if pigs are no longer there to munch away(devorar) at them, where will Cairo’s giant piles of leftovers(sobras) go?
sábado, 2 de maio de 2009
The pandemic threat
The pandemic threat(ameaça)
Apr 30th 2009
From The Economist print edition
It’s deadly serious; so even if the current threat fades, the world needs to be better armed
Illustration by KAL
IT IS said that no battle-plan survives contact with the enemy. This was certainly true of the plan drawn up over the past few years to combat an influenza pandemic. The generals of global health assumed that the enemy would be avian flu, probably passed from hens to humans, and that it would strike first in southern China or South-East Asia. In fact, the flu started in an unknown pig, and the attack came in Mexico, not Asia.
The hens, though, deserve some credit. The world has not had a pandemic (a global epidemic) of influenza since 1968. Four decades are long enough to forget that something is dangerous, and people might have done so had they not spent the past ten years considering the possibility that a form of bird flu which emerged in Hong Kong in 1997 might be one mutation away from going worldwide.
The new was raised on April 29th to just one notch below the level of a certified pandemic by the World Health Organisation. In an effort to halt(parar) the spread of the disease, Mexico’s president, Felipe Calderón, has announced that non-essential services should close down between May 1st and 5th, and people should stay at home. Part of the reason for worry is that, unlike ordinary flu, which mostly carries off the old, the victims of this disease are mostly young and otherwise healthy.
Still, this epidemic has not actually killed many people yet. That there have been a mere handful of confirmed deaths is probably the result of a lack of proper tests. But even if all the possibles are counted in, a couple of hundred fatalities cannot compare with the 30,000 deaths caused in America each year by seasonal influenza. So how scared should we be?
Apr 30th 2009
From The Economist print edition
It’s deadly serious; so even if the current threat fades, the world needs to be better armed
Illustration by KAL
IT IS said that no battle-plan survives contact with the enemy. This was certainly true of the plan drawn up over the past few years to combat an influenza pandemic. The generals of global health assumed that the enemy would be avian flu, probably passed from hens to humans, and that it would strike first in southern China or South-East Asia. In fact, the flu started in an unknown pig, and the attack came in Mexico, not Asia.
The hens, though, deserve some credit. The world has not had a pandemic (a global epidemic) of influenza since 1968. Four decades are long enough to forget that something is dangerous, and people might have done so had they not spent the past ten years considering the possibility that a form of bird flu which emerged in Hong Kong in 1997 might be one mutation away from going worldwide.
The new was raised on April 29th to just one notch below the level of a certified pandemic by the World Health Organisation. In an effort to halt(parar) the spread of the disease, Mexico’s president, Felipe Calderón, has announced that non-essential services should close down between May 1st and 5th, and people should stay at home. Part of the reason for worry is that, unlike ordinary flu, which mostly carries off the old, the victims of this disease are mostly young and otherwise healthy.
Still, this epidemic has not actually killed many people yet. That there have been a mere handful of confirmed deaths is probably the result of a lack of proper tests. But even if all the possibles are counted in, a couple of hundred fatalities cannot compare with the 30,000 deaths caused in America each year by seasonal influenza. So how scared should we be?
Pain but no panic
Pain but no panic
Apr 30th 2009
From The Economist print edition
A traditionally crisis-prone region is belying its reputation. But that has not spared it from the world recession
UNTIL recently many Latin Americans saw the financial crisis and the global recession as events happening somewhere else. But in the past six months the region’s economies have swiftly slumped along with the rest of the world, showing double-digit falls in industrial output. Workers have been laid off in Mexican car factories, Brazilian aircraft plants and Peruvian building sites. For Latin Americans such woes are sadly familiar: income per person in the region has fallen on five separate occasions since 1980. What is different this time is that Latin Americans are faring no worse than the rest of the world. And there are reasons to believe that their recession may be relatively short and mild. That may not be cause for celebration but it is a crumb of comfort.
The bad news is, however, quite bad. Latin American countries have been hit by four different recessionary forces. As the financial crisis in the developed world transmuted into a collapse of manufacturing, trade plunged: total exports for five of the region’s larger economies fell by a third between August and December, partly because fewer goods were sold and partly because the price of commodities fell.
The flow of capital to the region also dried up, leading to a steep rise in borrowing costs for governments and companies. The Institute of International Finance, a bankers’ group, thinks that net private capital flows to Latin America will fall by more than half this year compared with last, to $43 billion (down from a record $184 billion in 2007). Foreign banks have trimmed credit lines, especially for trade. In addition, remittances from Latin Americans working abroad have begun to contract, and fewer tourists have come visiting.
Apr 30th 2009
From The Economist print edition
A traditionally crisis-prone region is belying its reputation. But that has not spared it from the world recession
UNTIL recently many Latin Americans saw the financial crisis and the global recession as events happening somewhere else. But in the past six months the region’s economies have swiftly slumped along with the rest of the world, showing double-digit falls in industrial output. Workers have been laid off in Mexican car factories, Brazilian aircraft plants and Peruvian building sites. For Latin Americans such woes are sadly familiar: income per person in the region has fallen on five separate occasions since 1980. What is different this time is that Latin Americans are faring no worse than the rest of the world. And there are reasons to believe that their recession may be relatively short and mild. That may not be cause for celebration but it is a crumb of comfort.
The bad news is, however, quite bad. Latin American countries have been hit by four different recessionary forces. As the financial crisis in the developed world transmuted into a collapse of manufacturing, trade plunged: total exports for five of the region’s larger economies fell by a third between August and December, partly because fewer goods were sold and partly because the price of commodities fell.
The flow of capital to the region also dried up, leading to a steep rise in borrowing costs for governments and companies. The Institute of International Finance, a bankers’ group, thinks that net private capital flows to Latin America will fall by more than half this year compared with last, to $43 billion (down from a record $184 billion in 2007). Foreign banks have trimmed credit lines, especially for trade. In addition, remittances from Latin Americans working abroad have begun to contract, and fewer tourists have come visiting.
Life in thin slices
Life in thin slices
Apr 30th 2009
From The Economist print edition
An ancient smile may predict a modern divorce
A GRIM expression in a yearbook photo or family snapshot could mean more than just a passing bad mood. It could also signal that the subject is more likely to get divorced than someone with a big smile for the camera. Matthew Hertenstein and his colleagues at DePauw University in Greencastle, Indiana asked old boys and girls of the university to answer questions about their current sexual relationships and whether they had ever been divorced. The team then looked up pictures of their volunteers in the university’s yearbooks and graded the degree of their smiles. The less a person smiled, it turned out, the more likely he or she was to have been divorced over the course of a lifetime.
This research is a dramatic example of how “thin slices” of information can predict important aspects of people’s personalities. In past studies, researchers have shown that with very limited information—less than half a minute of interaction, the viewing of a video clip or just a look at a photograph—people can make accurate predictions about others’ sexual orientation, socioeconomic status, teaching ability and personality.
Dr Hertenstein was following up research which had shown that the women who smiled most in their college photos were most likely to be married by the age of 27, among other things. He wanted to see if the same held, over the longer term, for divorce. His study, to be published in Motivation & Emotion, looked at three groups. The first, of 306 people, came from alumni of the psychology department. The second group, of 349, was recruited from general alumni. The third, of 55 people, was recruited from the town. (In the last case, people were asked to send in photos of themselves, but were not told that the study was about smiling.) The researchers rated the photos of the subjects on a scale of two to ten. They also asked their volunteers various questions, including whether they had ever been divorced.
The relationship between smiling and divorce also held up among townspeople, even though many sent photographs of themselves as children. Facial expression predicted divorce even when the smile or frown was on a ten-year-old’s face. A photograph that records a split second from a lifetime is a very thin slice indeed. How could it predict a divorce decades in the future?
Apr 30th 2009
From The Economist print edition
An ancient smile may predict a modern divorce
A GRIM expression in a yearbook photo or family snapshot could mean more than just a passing bad mood. It could also signal that the subject is more likely to get divorced than someone with a big smile for the camera. Matthew Hertenstein and his colleagues at DePauw University in Greencastle, Indiana asked old boys and girls of the university to answer questions about their current sexual relationships and whether they had ever been divorced. The team then looked up pictures of their volunteers in the university’s yearbooks and graded the degree of their smiles. The less a person smiled, it turned out, the more likely he or she was to have been divorced over the course of a lifetime.
This research is a dramatic example of how “thin slices” of information can predict important aspects of people’s personalities. In past studies, researchers have shown that with very limited information—less than half a minute of interaction, the viewing of a video clip or just a look at a photograph—people can make accurate predictions about others’ sexual orientation, socioeconomic status, teaching ability and personality.
Dr Hertenstein was following up research which had shown that the women who smiled most in their college photos were most likely to be married by the age of 27, among other things. He wanted to see if the same held, over the longer term, for divorce. His study, to be published in Motivation & Emotion, looked at three groups. The first, of 306 people, came from alumni of the psychology department. The second group, of 349, was recruited from general alumni. The third, of 55 people, was recruited from the town. (In the last case, people were asked to send in photos of themselves, but were not told that the study was about smiling.) The researchers rated the photos of the subjects on a scale of two to ten. They also asked their volunteers various questions, including whether they had ever been divorced.
The relationship between smiling and divorce also held up among townspeople, even though many sent photographs of themselves as children. Facial expression predicted divorce even when the smile or frown was on a ten-year-old’s face. A photograph that records a split second from a lifetime is a very thin slice indeed. How could it predict a divorce decades in the future?
domingo, 26 de abril de 2009
Could Food Shortages Bring Down Civilization?
Could Food Shortages Bring Down Civilization?
The biggest threat to global stability is the potential for food crises in poor countries to cause government collapse
By Lester R. Brown Scientific American Magazine April 22, 2009
One of the toughest things for people to do is to anticipate sudden change. Typically we project the future by extrapolating from trends in the past. Much of the time this approach works well. But sometimes it fails spectacularly, and people are simply blindsided by events such as today’s economic crisis.
For most of us, the idea that civilization itself could disintegrate probably seems preposterous (absurdo). Who would not find it hard to think seriously about such a complete departure from what we expect of ordinary life? What evidence could make us heed(prestar atenção) a warning so dire(terrível, extremista)—and how would we go about responding to it? We are so inured (acostumado)to a long list of highly unlikely catastrophes that we are virtually programmed to dismiss them all with a wave of the hand: Sure, our civilization might devolve into(transformar em) chaos—and Earth might collide with an asteroid, too!
For many years I have studied global agricultural, population, environmental and economic trends and their interactions. The combined effects of those trends and the political tensions they generate point to the breakdown of governments and societies. Yet I, too, have resisted the idea that food shortages could bring down not only individual governments but also our global civilization.
I can no longer ignore that risk. Our continuing failure to deal with the environmental declines that are undermining the world food economy—most important, falling water tables(plato,lista de informações)), eroding soils and rising temperatures—forces me to conclude that such a collapse is possible.
The biggest threat to global stability is the potential for food crises in poor countries to cause government collapse
By Lester R. Brown Scientific American Magazine April 22, 2009
One of the toughest things for people to do is to anticipate sudden change. Typically we project the future by extrapolating from trends in the past. Much of the time this approach works well. But sometimes it fails spectacularly, and people are simply blindsided by events such as today’s economic crisis.
For most of us, the idea that civilization itself could disintegrate probably seems preposterous (absurdo). Who would not find it hard to think seriously about such a complete departure from what we expect of ordinary life? What evidence could make us heed(prestar atenção) a warning so dire(terrível, extremista)—and how would we go about responding to it? We are so inured (acostumado)to a long list of highly unlikely catastrophes that we are virtually programmed to dismiss them all with a wave of the hand: Sure, our civilization might devolve into(transformar em) chaos—and Earth might collide with an asteroid, too!
For many years I have studied global agricultural, population, environmental and economic trends and their interactions. The combined effects of those trends and the political tensions they generate point to the breakdown of governments and societies. Yet I, too, have resisted the idea that food shortages could bring down not only individual governments but also our global civilization.
I can no longer ignore that risk. Our continuing failure to deal with the environmental declines that are undermining the world food economy—most important, falling water tables(plato,lista de informações)), eroding soils and rising temperatures—forces me to conclude that such a collapse is possible.
The dawn of the animals
The dawn of the animals
Apr 8th 2009
From The Economist print edition
Which came first, the eggs or the algae?
PNAS
Though the fossiliferous explosion known as the Cambrian period is often thought of as the beginning of animal life, animals actually appeared for the first time during a geological twilight called the Ediacaran, 635m-542m years ago, between the end of a great ice age and the arrival of all those well-preserved Cambrian fossils. The object on the left, less than a millimetre across in reality, is an example of what were once thought to be the encysted forms of Ediacaran algae. However, its similarity to the object on the right, which is the egg of a modern species of crustacean, has led Phoebe Cohen of Harvard University and her colleagues to suggest in the Proceedings of the National Academy of Sciences that it, too, is the egg of an animal. Which animal, exactly, is not clear. No crustaceans are known from the Ediacaran. Common adult Ediacarans included jellyfish-like critters and things that resemble flattened grapefruit segments. How these are related to the rest of animal-kind is not known. But somewhere among them must lurk one of humanity’s ancient ancestors.
Apr 8th 2009
From The Economist print edition
Which came first, the eggs or the algae?
PNAS
Though the fossiliferous explosion known as the Cambrian period is often thought of as the beginning of animal life, animals actually appeared for the first time during a geological twilight called the Ediacaran, 635m-542m years ago, between the end of a great ice age and the arrival of all those well-preserved Cambrian fossils. The object on the left, less than a millimetre across in reality, is an example of what were once thought to be the encysted forms of Ediacaran algae. However, its similarity to the object on the right, which is the egg of a modern species of crustacean, has led Phoebe Cohen of Harvard University and her colleagues to suggest in the Proceedings of the National Academy of Sciences that it, too, is the egg of an animal. Which animal, exactly, is not clear. No crustaceans are known from the Ediacaran. Common adult Ediacarans included jellyfish-like critters and things that resemble flattened grapefruit segments. How these are related to the rest of animal-kind is not known. But somewhere among them must lurk one of humanity’s ancient ancestors.
domingo, 19 de abril de 2009
Twice blessed
Twice blessed
Apr 16th 2009
From The Economist print edition
Bilingual babies are precocious decision-makers
WHETHER to teach young children a second language is disputed among teachers, researchers and pushy parents. On the one hand, acquiring a new tongue is said to be far easier when young. On the other, teachers complain that children whose parents speak a language at home that is different from the one used in the classroom sometimes struggle in their lessons and are slower to reach linguistic milestones. Would 15-month-old Tarquin, they wonder, not be better off going to music classes?
A study just published in the Proceedings of the National Academy of Sciences may help resolve this question by getting to the nub(ponto chave) of what is going on in a bilingual child’s brain, how a second language affects the way he thinks, and thus in what circumstances being bilingual may be helpful. Agnes Kovacs and Jacques Mehler at the International School for Advanced Studies in Trieste say that some aspects of the cognitive development of infants raised in a bilingual household must be undergoing acceleration in order to manage which of the two languages they are dealing with.
The aspect of cognition in question is part of what is termed the brain’s “executive function”. This allows people to organise, plan, prioritise activity, shift their attention from one thing to another and suppress habitual responses. The researchers speculate that it might be the fact of having to learn two languages in the same setting that requires greater use of executive function. So whether those benefits accrue to(crescer, aumantar =increase) children who learn one language at home, and one at school, remains unclear.
Apr 16th 2009
From The Economist print edition
Bilingual babies are precocious decision-makers
WHETHER to teach young children a second language is disputed among teachers, researchers and pushy parents. On the one hand, acquiring a new tongue is said to be far easier when young. On the other, teachers complain that children whose parents speak a language at home that is different from the one used in the classroom sometimes struggle in their lessons and are slower to reach linguistic milestones. Would 15-month-old Tarquin, they wonder, not be better off going to music classes?
A study just published in the Proceedings of the National Academy of Sciences may help resolve this question by getting to the nub(ponto chave) of what is going on in a bilingual child’s brain, how a second language affects the way he thinks, and thus in what circumstances being bilingual may be helpful. Agnes Kovacs and Jacques Mehler at the International School for Advanced Studies in Trieste say that some aspects of the cognitive development of infants raised in a bilingual household must be undergoing acceleration in order to manage which of the two languages they are dealing with.
The aspect of cognition in question is part of what is termed the brain’s “executive function”. This allows people to organise, plan, prioritise activity, shift their attention from one thing to another and suppress habitual responses. The researchers speculate that it might be the fact of having to learn two languages in the same setting that requires greater use of executive function. So whether those benefits accrue to(crescer, aumantar =increase) children who learn one language at home, and one at school, remains unclear.
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