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.
domingo, 28 de junho de 2009
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.
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