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An exotic type of symmetry - suggested by string theory and theories of high-energy particle physics, and also conjectured for electrons in solids under certain conditions - has been observed experimentally for the first time. 

An international team, led by scientists from Oxford University, report in a recent article in Science how they spotted the symmetry, termed E8, in the patterns formed by the magnetic spins in crystals of the material cobalt niobate, cooled to near absolute zero and subject to a powerful applied magnetic field.

The material contains cobalt atoms arranged in long chains and each atom acts like a tiny bar magnet that can point either ‘up’ or ‘down’. 

When a magnetic field is applied at right angles to the aligned spin directions, the spins can ‘quantum tunnel’ between the ‘up’ and ‘down’ orientations. At a precise value of the applied field these fluctuations ‘melt’ the ferromagnetic order of the material resulting in a ‘quantum critical’ state.

‘You might expect to see random fluctuations of the spins at this critical point but what we uncovered was a remarkable structure in the resonances of the magnetic spins indicating a perfectly harmonious state,’ said Radu Coldea from Oxford University’s Department of Physics who led the team.

As the critical state was approached the researchers observed that the chain of atoms behaved like a ‘magnetic guitar string’.

Radu added: ‘The tension comes from the interaction between spins causing them to magnetically resonate. We found a series of resonant modes. Close to the critical field the two lowest resonant frequencies approached closely the golden ratio 1.618…, a characteristic signature of the predicted E8 symmetry.’

He is convinced that this is no coincidence and it reflects a subtle form of order present in the quantum system.

The resonant states seen experimentally in cobalt niobate may be our first glimpse of complex symmetries that can occur in the quantum world. “The results suggest that similar ‘hidden’ symmetries may also govern the physics of other materials near quantum critical points where electrons organize themselves according to quantum rules for strong interactions,’ Radu told us.

The research was supported by EPSRC and Radu aims to use a new EPSRC grant to explore the physics of materials near quantum criticality.

The team included Dr Radu Coldea, Dr Elisa Wheeler and Dr D Prabhakaran from Oxford University’s Department of Physics, as well as researchers from Helmholtz Zentrum Berlin, ISIS Rutherford Laboratory, and Bristol University.

At the current growth rate the global population is predicted to reach 10 billion by 2050. To feed this many people, food production worldwide will need to double during a period when climate change will worsen, fossil fuels will dwindle, and water availability will become unpredictable.

In addition, if we are to protect what biodiversity we can, this doubling of agricultural output must take place using the same amount of farmland, without impacting upon remaining natural habitats.

To tackle this problem, scientists in Oxford University’s Department of Plant Sciences are aiming to develop high-yield crop strains which will be better adapted to this climate-altered, resource-poor agricultural landscape of the near future.

Boosting rice crops
Professor Jane Langdale, Head of the Department of Plant Sciences, is engaged in the ‘C4 Rice’ project, an international effort funded by the Bill & Melinda Gates Foundation [more here]. 700 million people in Asia currently depend on rice for the bulk of their calorific intake and it is predicted that during the next 40 years, rice production needs to increase by 50 per cent in order to feed the growing Asian population, whilst adapting to adverse changes in climate and water availability.

Photosynthesis converts carbon dioxide and the energy from sunlight into chemical energy and takes place in cell organelles called chloroplasts. The chemical energy produced in these chloroplasts is then used by plants to live, grow, and in the case of crops, produce grain.

Conventional rice varieties use a standard photosynthesis pathway known as ‘C3’, but under certain conditions, such as warmer temperatures, this pathway is inefficient. A number of plants, including maize, have evolved an extra photosynthesis pathway, called ‘C4’, to solve this problem. The C4 photosynthesis pathway can increase efficiency by 50 per cent and introducing it into rice could provide the answer to Asia’s impending food problem.

The C4 Rice project is often quoted as being ‘highly ambitious’. In order to work, large changes need to be made to both the anatomy of rice leaves and the chemical reactions that take place inside them. However, there is encouraging evidence that it could be done.

Jane’s work on the GLK genes suggests that they may play a role in regulating whether a plant’s chloroplasts use C3 or C4 photosynthesis. Ongoing work in her laboratory seeks to put GLK genes from maize, a naturally C4 crop, into rice plants. Her work on chloroplasts began due to an interest in the genetic control of development in plants, rather than a specific aim to put C4 photosynthesis into other plant species. Whilst developing new C4 crops had always seemed like an interesting idea, she never thought it would be realistic.

20 years of chloroplast research later, Jane was ready to move into new research areas. It was at this point, in 2006, that the International Rice Research Institute (IRRI) invited Jane to a C4 Rice Consortium workshop. Originally reluctant to go, she was persuaded to attend by Julian Hibberd from the University of Cambridge, and found herself getting excited by the proposed project. She is now 5 months into a 3 year “proof of concept” project involved in testing the feasibility of C4 Rice, a necessary step called for by a paper in Current Opinions in Plant Biology written with Julian and John Sheehy from IRRI last year.

Using less fertiliser
As well as facing climate change, 21st century agriculture will also have to cope with the decline in fossil fuels. The work of Oxford’s new Sherardian Professor of Botany, Liam Dolan, aims to produce crops which grow healthily without excessive phosphate-rich fertiliser application.

Phosphate is required by all living organisms to build cellular components and the low availability of phosphate in natural environments can severely limit plant growth. The soil of all of sub-Saharan Africa and one third of China is deficient in this crucial nutrient. The application of artificial fertilisers all over the world has so far dealt with this problem and contributed to the increase in productivity seen in the Green Revolution of the 20th Century.

Phosphate is extracted from mines, mainly in Morocco, the USA, China, the Former Soviet Union and South Africa, with 80 per cent of the phosphate produced being put into fertilisers. The extraction and transport of phosphate for agricultural use constitutes a considerable annual cost and carries a large carbon footprint. Furthermore, like oil, phosphate reserves are finite, and some predictions claim that phosphate mines could be exhausted within the next 30 years.

Liam’s work aims to develop crops which are better adapted to scavenge their own phosphate from the soil, making them less dependent on artificial fertilisers.

Plants can naturally extract their own phosphate from the soil using root hairs, single-cell structures which grow along roots. Liam’s research group have discovered a family of genes which control root hair growth and they are working to modulate the expression of these genes in crop plants. Their aim is to increase the number of root hairs a plant produces in response to naturally occurring phosphate in the soil. They have developed transgenic wheat and rice varieties capable of producing longer root hairs and are now moving on to field experiments to test the yield of these plants in the absence of commercial fertiliser.

Unlike Jane Langdale’s chloroplast work, this has always been the aim for Liam. He jokes that his team are now finally at the stage he had hoped to be at by the end of his PhD, explaining that this has been a very large project, starting from scratch and requiring the discovery of all the necessary genes involved.

Planning for 21st Century
In light of the global food security crisis we will soon be facing, the University’s Department of Plant Sciences will next year be launching a 21st Century Crops research initiative. This initiative seeks to found an Oxford Professorship in Crop Science and to encourage translational research, so that discoveries made about plant metabolism, growth and development can be transferred to agriculturally valuable crop plants.

However, both Jane and Liam believe that whilst plant science has a lot to offer in solving the food security challenge, the role of governments and funding bodies is crucial, a point that was emphasised at the 'Food Security in the 21st Century' Symposium hosted by the Department’s graduate students last October.

Due to the unequal distribution of global wealth, the countries facing the most immediate problems do not have the funds to overcome them. Jane argues that to tackle food security there must be sustained funding and input from wealthy countries in order to bring about developing nation benefits. Liam points out that every day the same number of people die from malnutrition as from cancer, reflecting the bias of interest in developed countries. However, whilst scientific research alone cannot solve the issue of food security in the face of global politics, it is, says Jane, a very exciting time to be a plant scientist. 

Penny Sarchet is based at Oxford University's Department of Plant Sciences

To celebrate BBC Year of Science 2010 three Oxford scientists are appearing on BBC Radio Oxford every day this week to perform live science experiments.

Andrew Steele, Rosalind West, and Suzie Sheehy - three DPhil students from Oxford University's Department of Physics - will be joining Breakfast Show presenter Malcolm Boyden on BBC Oxford 95.2 FM at 7:15am [or the repeat at 8:15am] every morning.

They'll be performing and explaining different science demonstrations and exploring answers to 'impossible questions': such as how the Universe came into existence and what the future of computing has in store.

In their first slot they showed Malcolm how anyone can find their own retinal blind spots with just a sheet of paper and a pen. They then went on to show how you can see the retinal blood vessels that criss-cross your vision, but that the brain normally 'edits' out, with a pen torch.

If you missed this morning's edition watch what they got up to on this BBC Oxford video or listen again on BBC iPlayer.

UPDATE: Watch a video of Tuesday's experiments here.

New images released yesterday from ESA's Herschel Space Observatory are giving astronomers the most detailed view yet of what space looked like 12 billion years ago.

The pictures show tens of thousands of newly-discovered galaxies at the early stages of formation, some thought to have formed just over a billion years after the Big Bang.

The images will be analysed as part of the HerMES project which involves over 100 astronomers from six countries and is led by Seb Oliver of the University of Sussex.

HerMES team member Dimitra Rigopoulou, of Oxford University's Department of Physics and the Rutherford Appleton Laboratory, told me: 'It is a tremendous leap forward for understanding how galaxies form their stars. In just one picture we can see ten times as many galaxies as have been seen by all the telescopes like this one, up until today.'

The HerMES project aims to produce a map of the Universe as it was around eight billion years ago, based on data received from Herschel's SPIRE infrared camera.

Dimitra added: 'Seeing such stunning images after just 14 hours of observations gives us high expectations for the full length observations over much larger regions of the Universe. This will give us a much clearer idea of how star formation has progressed throughout the history of the Universe.'

We’d all like to think that a small tipple – a glass of wine or a pint of beer, say – is not going to be bad for us, particularly at this time of year. So how much more are we likely to pounce on reports that such moderate amounts of alcohol might actually have some beneficial effects, like lower risk of heart disease? 

There are a large number of such reports around to seize on. This week, The Telegraph light-heartedly covered a small study that suggested compounds present in champagne could have benefits for the heart, although further reading suggests this is still very much a hypothesis rather than a demonstration of a real effect on heart disease. Similarly, it’s worth reading this to judge a recent large-scale Spanish survey of the effects of really quite large amounts of alcohol on the heart.

So how do we make sense of all of this? Not least because when alcohol consumption spills over into heavy drinking, we know very well that it becomes a very serious and costly public health problem not just for individuals but also wider society.

OxSciBlog turned to Dr Naomi Allen of the Cancer Epidemiology Unit [CEU] at the University of Oxford. Naomi led research into the effects of drinking alcohol on rates of cancer as part of the Million Women Study.

OxSciBlog: What do we know about how light-to-moderate amounts of alcohol can affect health?
Naomi Allen: Everyone knows that heavy drinking is bad for our health, but what about the health effects of more moderate amounts of alcohol that most of us drink? Indeed, people who drink one or two drinks every day appear to have the lowest death rates (ie they live longer) compared with people who don’t drink at all and people who drink more heavily.

This is largely because moderate alcohol drinking has been shown to reduce the risk of heart disease in middle to late age.

However, moderate drinking (one to two alcoholic drinks each day) also increases the risk of developing certain types of cancer, especially breast cancer in women, but also cancers that were previously only thought to be related to heavy drinking, such as cancer of the liver, rectum and in smokers, cancers of the mouth and throat.

Most of this increased risk is for breast cancer, so the potential risks of moderate drinking are perhaps of most relevance for women. In particular, the risks may be of greatest concern for middle-aged women, whose risk of developing breast cancer is much higher than the risk of heart disease. For women over the age of 75, the risk of heart disease increases and the risks and benefits of moderate drinking are not so clear.

OSB: Why might alcohol be beneficial?
NA: Alcohol is believed to protect against heart disease in several ways, the most important of which is through increasing the amount of ‘good’ cholesterol in the blood (called high-density lipoprotein) that helps prevent blocked arteries, and also through reducing the ‘stickiness’ of the blood.

There has been much speculation that red wine may be most beneficial (due to the high content of compounds called polyphenols contained in some red grapes), but the evidence to date suggests that it is the alcohol itself, rather than other compounds contained in alcoholic drinks, that protects against heart disease.

But I would not recommend people start drinking specifically to protect the heart, as there are health risks involved in drinking moderate amounts of alcohol, and there are safer alternative ways to reduce the risk of heart disease, such as to start taking more physical activity, to eat a healthy balanced diet and to stop smoking.

OSB: What do we know about the dangers of binge drinking?
NA: The adverse health effects of heavy drinking are varied, devastating and affect all ages: in youth, alcohol tends to be related to mental and behavioural disorders, injuries and violence, whilst in middle- and late-age, heavy drinking is related to liver disease and certain cancers.

However, for people who drink more moderate amounts of alcohol, it is not yet known whether the pattern of drinking affects the long-term risks for cancer (i.e. whether drinking one drink every day or bingeing on seven drinks in one session at the weekend has the same effect).

OSB: We seem to get endless reports of new studies with conflicting conclusions. Why is it so difficult to carry out a definitive study?
NA: The main reason there have been so many conflicting findings is because most studies have been too small to detect reliably the effects of low to moderate amounts of alcohol on different health outcomes at the same time. Up until now, most studies have examined the association of alcohol on a single disease (eg a specific cancer type, or heart disease).

Many thousands of participants are needed to reliably compare rates of diseases within the same study population. Only by establishing these very large epidemiological studies, such as the Million Women Study in the UK (with over 1.3 million middle-aged women recruited 1996–2001), can we begin to directly compare future disease rates among women according to their usual alcohol consumption.

With linkage to both regional cancer registries and, more recently, hospital admissions databases, it is now possible to investigate the association of alcohol with cancer, heart disease and other outcomes in this population, and we will soon be in a position to comment on the overall risks and benefits of moderate alcohol drinking in women.

OSB: And do you have any advice as we look forward to all our Christmas celebrations?
NA: I don’t want to be a party-pooper and berate people who have a celebratory tipple at Christmas time, or even those who have one every day to celebrate life’s daily grind. However, the three wise men might advise middle-aged women not to overindulgence too much on a daily basis, especially if they have other risk factors for breast cancer.