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Organic tomatoes have more antioxidants
CLIVE CHAMPION/FOODPIX/JUPITER
This week–
Before the big bang there was amnesia SASWATO DAS
SOME cosmologists think that our universe has been cycling through an endless series of big bangs and big crunches. If so, it implies the universe is doomed to repeat the same thing over and over. A new study, however, suggests that with each big bang, the universe mostly forgets its past and starts anew. The accepted wisdom in modern cosmology is that it is meaningless to ask what came before the big bang. That’s because the big bang is what physicists call a “singularity” – a moment at which the equations of physics break down. “No one is happy with the big bang singularity,”
“Most, but not all, of the information about what came before the big bang gets irretrievably lost” says Martin Bojowald, a theorist at the Pennsylvania State University, University Park. Bojowald works on loop quantum gravity (LQG) – a theory that seeks to unify the otherwise incompatible theories of general relativity and quantum mechanics. In LQG, space-time is made of tiny interconnected loops, each only 10-35 metres across, that form a smooth fabric
NEW VERSION JUST RELEASED!
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www.endnote.co.uk T: 01462 480055 E: [email protected]
16 | NewScientist | 7 July 2007
much like a shirt’s fabric is smooth even though it is woven from separate threads. Bojowald and his colleagues have run the equations of LQG backwards and shown that they can avoid the singularity. They showed that as the universe collapses, it reaches a point at which it bounces back in a big bang, and the process repeats (New Scientist, 24 April 2006, p 15). Does that mean that one day we can, either mathematically or via observations, know about the pre-big bang universe? To answer this question, Bojowald developed a simple LQG model to determine the limits of what we can know. In his model, he assumed that the physical properties of the universe were the same everywhere and that the kind of matter it contained did not interact with itself. The model included gravity but not radiation. The model showed that most, but not all, of the information about what came before the big bang gets irretrievably lost through the big bang transition. And in a perpetual cycle of big bangs and crunches, this information loss means no two universes are ever the same. Bojowald calls this “cosmic forgetfulness” (Nature Physics, DOI: 10.1038/nphys654). Cosmologist Paul Steinhardt of Princeton University says that Bojowald’s model is right in principle. “It’s important to lose some information, but not everything,” he says. Thomas Thiemann of the Max Planck Institute for Gravitational Physics in Golm, Germany, says that although some of Bojowald’s assumptions may turn out to be too simple, the model is “the cleanest derivation of a pre-big bang scenario that any physical theory has delivered so far”. ●
–Better starve ’em?–
Organic tomatoes win on level farming field IS ORGANIC food healthier for you, after all? A 10-year study comparing organic tomatoes with those grown conventionally suggests that it may be. It’s the kind of evidence that proorganic groups have been desperate to dig up, as most studies have suggested otherwise. According to the new findings, levels of the flavonoids quercetin and kaempferol were found to be on average 79 and 97 per cent higher, respectively, in organic tomatoes. Flavonoids such as these are known antioxidants and have been linked to reduced rates of cardiovascular disease, some forms of cancer and dementia, says Alyson Mitchell, a food chemist who led the research at the University of California, Davis. Differences in soil quality, irrigation practices and the handling of harvested produce have made direct comparisons difficult in the past, says Mitchell. So in this study, due to be published in the Journal of Agricultural and Food Chemistry, the researchers used data from a longterm project in which standardised farming techniques are used to reveal trends in crop productivity. Mitchell’s team say the finding
can be explained by the availability of nitrogen. Flavonoids are produced as a defence mechanism that can be triggered by nutrient deficiency. The inorganic nitrogen in conventional fertiliser is easily available to plants and so, the team suggests, the lower levels of flavonoids are probably caused by overfertilisation. Previous research has found no differences between organic and conventional crops such as wheat or carrots. Meanwhile a study proclaiming that organic milk had higher levels of omega-3 fatty acids failed to convince the UK’s Food Standards Agency (FSA), which pointed out that these short-chained fatty acids do not have the healthpromoting benefits offered by longchained omega-3 oils. This latest study does not prove that a healthy diet must be organic. The evidence of health benefits for flavonoids is conflicting, says Peter Bramley at Royal Holloway, University of London. And even if such benefits exist, higher flavonoid levels do not necessarily make organic food healthier, says John Krebs, former chair of the FSA and now at the University of Oxford. “This depends on the relevance of the differences to the human body,” he says. “Tomato ketchup has higher levels of lycopene than either organic or conventional tomatoes. So if you wanted lots of lycopene you should eat ketchup.” Duncan Graham-Rowe ● www.newscientist.com
This week–
Before the big bang there was amnesia SASWATO DAS
SOME cosmologists think that our universe has been cycling through an endless series of big bangs and big crunches. If so, it implies the universe is doomed to repeat the same thing over and over. A new study, however, suggests that with each big bang, the universe mostly forgets its past and starts anew. The accepted wisdom in modern cosmology is that it is meaningless to ask what came before the big bang. That’s because the big bang is what physicists call a “singularity” – a moment at which the equations of physics break down. “No one is happy with the big bang singularity,”
“Most, but not all, of the information about what came before the big bang gets irretrievably lost” says Martin Bojowald, a theorist at the Pennsylvania State University, University Park. Bojowald works on loop quantum gravity (LQG) – a theory that seeks to unify the otherwise incompatible theories of general relativity and quantum mechanics. In LQG, space-time is made of tiny interconnected loops, each only 10-35 metres across, that form a smooth fabric
NEW VERSION JUST RELEASED!
The essential tool for writing your research papers
www.endnote.co.uk T: 01462 480055 E: [email protected]
16 | NewScientist | 7 July 2007
much like a shirt’s fabric is smooth even though it is woven from separate threads. Bojowald and his colleagues have run the equations of LQG backwards and shown that they can avoid the singularity. They showed that as the universe collapses, it reaches a point at which it bounces back in a big bang, and the process repeats (New Scientist, 24 April 2006, p 15). Does that mean that one day we can, either mathematically or via observations, know about the pre-big bang universe? To answer this question, Bojowald developed a simple LQG model to determine the limits of what we can know. In his model, he assumed that the physical properties of the universe were the same everywhere and that the kind of matter it contained did not interact with itself. The model included gravity but not radiation. The model showed that most, but not all, of the information about what came before the big bang gets irretrievably lost through the big bang transition. And in a perpetual cycle of big bangs and crunches, this information loss means no two universes are ever the same. Bojowald calls this “cosmic forgetfulness” (Nature Physics, DOI: 10.1038/nphys654). Cosmologist Paul Steinhardt of Princeton University says that Bojowald’s model is right in principle. “It’s important to lose some information, but not everything,” he says. Thomas Thiemann of the Max Planck Institute for Gravitational Physics in Golm, Germany, says that although some of Bojowald’s assumptions may turn out to be too simple, the model is “the cleanest derivation of a pre-big bang scenario that any physical theory has delivered so far”. ●
–Better starve ’em?–
Organic tomatoes win on level farming field IS ORGANIC food healthier for you, after all? A 10-year study comparing organic tomatoes with those grown conventionally suggests that it may be. It’s the kind of evidence that proorganic groups have been desperate to dig up, as most studies have suggested otherwise. According to the new findings, levels of the flavonoids quercetin and kaempferol were found to be on average 79 and 97 per cent higher, respectively, in organic tomatoes. Flavonoids such as these are known antioxidants and have been linked to reduced rates of cardiovascular disease, some forms of cancer and dementia, says Alyson Mitchell, a food chemist who led the research at the University of California, Davis. Differences in soil quality, irrigation practices and the handling of harvested produce have made direct comparisons difficult in the past, says Mitchell. So in this study, due to be published in the Journal of Agricultural and Food Chemistry, the researchers used data from a longterm project in which standardised farming techniques are used to reveal trends in crop productivity. Mitchell’s team say the finding
can be explained by the availability of nitrogen. Flavonoids are produced as a defence mechanism that can be triggered by nutrient deficiency. The inorganic nitrogen in conventional fertiliser is easily available to plants and so, the team suggests, the lower levels of flavonoids are probably caused by overfertilisation. Previous research has found no differences between organic and conventional crops such as wheat or carrots. Meanwhile a study proclaiming that organic milk had higher levels of omega-3 fatty acids failed to convince the UK’s Food Standards Agency (FSA), which pointed out that these short-chained fatty acids do not have the healthpromoting benefits offered by longchained omega-3 oils. This latest study does not prove that a healthy diet must be organic. The evidence of health benefits for flavonoids is conflicting, says Peter Bramley at Royal Holloway, University of London. And even if such benefits exist, higher flavonoid levels do not necessarily make organic food healthier, says John Krebs, former chair of the FSA and now at the University of Oxford. “This depends on the relevance of the differences to the human body,” he says. “Tomato ketchup has higher levels of lycopene than either organic or conventional tomatoes. So if you wanted lots of lycopene you should eat ketchup.” Duncan Graham-Rowe ● www.newscientist.com