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Particle physics

Magnetic monopoles are fundamentally important but highly elusive elementary particles exhibiting quantised magnetic charge. The prospect for studying them has brightened in recent years with the theoretical realisation that, in certain classes of magnetic insulators, the thermally excited states exhibit all the characteristics of magnetic monopoles.

Now, a collaboration led by Professor JC Séamus Davis and Professor Stephen J Blundell of the University of Oxford’s Department of Physics has developed a new approach to detecting and studying these ‘emergent’ magnetic monopoles – including the discovery that, when amplified, the noise they make is audible to humans. The findings are published in the journal Nature.

In 2018, Professor Blundell and his colleagues Dr Franziska Kirschner and Dr Felix Flicker predicted that the random motion of magnetic monopoles inside these compounds would generate a very specific kind of magnetisation noise.

This means that a crystal of one of these magnetic insulators should spontaneously generate wildly and randomly fluctuating magnetic fields both internally and externally, as the monopoles move around. The catch was that these fields vary rapidly and randomly at every point, so that the net fluctuating field through a sample was predicted to be near one billionth of the Earth’s field.

In response, Professor Davis and colleague Dr Ritika Dusad built an exquisitely sensitive magnetic-field-noise spectrometer based on a superconducting quantum interference device – a SQUID.

Professor Davis said: “Virtually all the predicted features of the magnetic noise coming from a dense fluid of magnetic monopoles were then discovered emerging from crystals of Dy2Ti2O7. Extraordinarily, because this magnetic monopole noise occurs in the frequency range below 20kHz, when amplified by the SQUID it is actually audible to humans.”

Professor Blundell added: “What makes magnetic monopoles fascinating is that they ‘emerge’ from a dense lattice of magnetic monopoles, and this makes their motion highly constrained – very different from a typical gas of charged particles. This observation led us on a search for the signature of this constrained motion in the magnetic noise spectrum. These exciting results open up the possibility of using magnetic noise to study many other exotic magnetic systems containing different species of emergent particles.”

Breathing with your brain

Researchers from the University of Oxford have been sharing their work with the public at the Royal Society Summer Science Exhibition (1-7 July 2019).

Breathe Oxford is a diverse group of neuroscientists, psychologists and clinicians studying the neuroscience of breathlessness. Their work shows that breathing is about more than just the lungs. In fact, the brain has a powerful influence on our experiences. This explains why some people still feel out of breath, even when they have been provided with medical care.

They explore how the brain controls our feelings of being out of breath using cutting-edge brain imaging technology. Understanding this control system could lead to revolutionary, personalised treatments for breathlessness.

Their exhibit at the Royal Society Summer Science Exhibition will bring the topic of ‘Breathing with your Brain’ to life, helping visitors to understand the how the brain controls our feelings of being out of breath.

Researcher and lead organiser Dr Sarah Finnegan said: 'Our research has shown the power of the brain-body interaction in influencing how we perceive our breathing.

'This is a relationship that we are only now just beginning to understand, and we hope eventually to develop target treatments for individuals, helping millions of people who are limited by their breathlessness.

'We are thrilled to be able to share some of the cutting-edge neuroscience that takes place at Oxford with visitors to the Royal Society, and hopefully we can inspire some future scientists!'

It is estimated that one in nine people experience some form of breathlessness, which is most common in conditions such as heart failure, lung disease, panic disorder and Parkinson’s. But there are also significant numbers of people who have unexplained breathlessness, which Breathe Oxford hypothesise might be driven by the networks in the brain.

Breathe Oxford has examined breathlessness in athletes, healthy individuals and people with chronic lung disease, seeking clues as to why some individuals become disabled by their breathlessness, while others, with the same lung function, live normal lives.

Visitors to the exhibit will be able to simulate living with chronic breathlessness by exercising on the ‘Steppatron’ with a straw in their mouth and a clip on their nose. They will also be able to witness the brain’s relationship with breathing on a 3D-printed scale model of a human torso with breathing lungs and LED lights which will highlight the neural pathways between the brain and the lungs. A specially commissioned animation will also reveal more about the background to the science.

Other stalls at the Summer Exhibition this year that involve Oxford research are:

Robots in the Danger Zone - Dr Maurice Fallon and others from the Department of Engineering Science's Oxford Robotics Institute will be demonstrating their research into robotics for inspection of dirty, dull and dangerous places, specifically with walking robots, such as their quadruped ANYmal. The stand is being presented by the ORCA Robotics Hub. See a video of the group's work here.

Living on the Moon! - an interactive experience highlighting the progress of lunar science since the Apollo 11 Moon landings 50 years ago. The exhibit illustrates the journey from Moon landing, to Lunar sample science, to the current generation of Moon rovers looking for water on the Moon, and provides a look forward to the next 50 years and a vision of a permanent human presence on the Moon. (Researcher: Dr Neil Bowles from the Department of Physics.)

In Your Element - 150 years of the periodic table: Investigating the elements that are essential to life. Biogeochemists from the Department of Earth Sciences' OceanBug team are presenting the journey of elements from the earth’s crust through the ocean and ultimately to feed life throughout Earth’s history. The exhibit is led by the University of Warwick.

Frozen Lake Baikal

By Samar Khatiwala

The concentration of CO2 in the atmosphere at the last ice age, some 19,000 years ago, was about a third lower than just prior to the Industrial Revolution. Where this carbon was stored during that frozen time is a mystery scientists have long sought to solve.

Most explanations for this “missing” CO2 – equivalent to about 200 billion tons of carbon or 20 years’ worth of anthropogenic emissions – have focused on the ocean. The reason is that, owing to some rather peculiar chemistry, CO2 is highly soluble in seawater. Consequently, the ocean contains roughly 60 times more CO2 than the atmosphere.

Illustration of the two main mechanisms Illustration of the two main mechanisms identified by this study to explain lower atmospheric CO2 during glacial periods. Left: present-day conditions; right: conditions around 19,000 years ago during the Last Glacial Maximum. 

Credit: Illustration by Andrew Orkney, University of Oxford.

In the way that a chilled glass of sparkling wine will remain fizzier for longer than a warm one (solubility increases with decreasing temperature), more CO2 must have been dissolved in the ocean during the last ice age when the ocean was on average 2.5ºC cooler. But previous studies, which essentially treated the ocean as a large tub of fizzy wine, have concluded that this mechanism can only explain about a quarter of the CO2 change. So what else is going on?

Well, we know that the ocean is (sadly!) not like a glass of Prosecco. Currents at the surface move water from the tropics to high latitudes. Along the way the water absorbs CO2 from the atmosphere as it cools, until it become dense enough to sink into the deep, taking dissolved carbon with it. This process is called the “solubility pump” since it is akin to “pumping” carbon down from the surface into the interior.

The pump doesn’t operate at full capacity, though, as the rate of absorption is quite slow and when the water sinks it actually contains much less CO2 than it is theoretically capable of absorbing from the atmosphere.

The more the water has to cool during its poleward journey, the greater the deficit. Reconstructions of sea surface temperature suggest that this gradient was smaller during the last ice age, with more cooling at mid-latitudes and less in polar regions, where the water is already close to freezing.

This led us to hypothesize that earlier studies, which had not only neglected this “disequilibrium” effect but also assumed that the ocean cooled uniformly, may have underestimated the effect of temperature.

To test this idea we developed a novel computer model which both accounts for disequilibrium and reproduces the reconstructed, non-uniform pattern of sea surface temperature change. Sure enough, the model predicts almost double the CO2 absorption as previous estimates and suggests that temperature can explain as much as half the glacial-interglacial atmospheric CO2 change.

In addition, ocean biology also plays a critical role in carbon storage. Like plants on land, marine algae absorb CO2 from the atmosphere during photosynthesis. When they die they sink into the deep ocean where bacteria feed on them to respire CO2 that then dissolves into the seawater. This “biological pump” doesn’t operate at full capacity either, as in large parts of the ocean algae are starved of iron (think of Popeye without his spinach!), an essential micronutrient supplied primarily by wind-borne dust.

As glacial periods were likely windier and dustier, more iron may have been supplied during those times, “fertilizing” algal growth and drawing down atmospheric CO2. But earlier studies had concluded that this could only account for about a tenth of the full CO2 change. Our new simulations informed by recent data on glacial dust fluxes can, on the other hand, explain a much more hefty quarter of the “missing” CO2.

If it’s true that these processes which were previously considered insignificant, are the biggest drivers of glacial-interglacial CO2 change, it’s perhaps even more surprising that the two processes widely believed to be the most important turn out to be minor players.

The current consensus is that a slowdown in the “overturning” circulation in the Atlantic and massive expansion of sea ice off Antarctica were the likely drivers of the CO2 change. However, our simulations show that if anything, both of these make the biological pump less efficient during glacial periods and thus increase atmospheric CO2!

Exciting as these new results are, their real significance lies in illuminating and untangling the complex interactions and feedbacks between the various processes that make up the ocean carbon cycle. Plenty more research will be needed before the final word on the cause of ice ages is written!

Read the full paper: Air-sea disequilibrium enhances ocean carbon storage during glacial periods in Science Advances.

Samar Khatiwala is Professor of Earth Sciences at the Department of Earth Sciences, University of Oxford. Find out more.

Water flowing into sink

By Kevin Grecksch

Whenever I start a presentation about water governance, I ask the audience if they know what the price of a litre of tap water is. Usually the room goes quiet, shoulders shrug and only a few make a guess, usually an overestimation. My next question is about the price of a litre of petrol. Within a split second, I get the right answer from the audience.

Water is indispensable, not only for humans, but for all living things. Yet our relationship with water is out of touch. In developed countries, drinking water is readily available everywhere: from the tap, the supermarket, and the corner shop. Most of us take water for granted; many do not realise just how important water really is and what we use it for. Besides drinking water, water is used in production processes, both industrial and in the food and drinks sector. We trade water in reality and virtually, we regulate water, we divert water, we pollute water, we fight over water, we rely on water to cool thermal power plants, and most importantly, water will be the medium through which climate change impacts are felt and experienced. Water can also be a threat. Floods and droughts endanger and destroy livelihoods, kills people and animals, and contributes to the spread of vector-borne diseases.

Water is an important issue, if not the most important, yet at the same time it cannot be singled out as it is part of the wider environmental story. That story tells us about the interdependencies and links between water and other sectors, such as agriculture, energy, forestry, manufacturing, and waste disposal. For example, a simple daily routine such as a hot shower involves not only the public water supply, but also relies on electricity or gas to heat up the water. Furthermore, water is a highly social issue. It is humans who make decisions about water, and who gets it and how much.         

Sustainable water governance is therefore a precondition for successful climate change adaptation. Water governance describes the steering, coordination and decision-making processes of actors to govern water. This includes laws, regulations, public participation and education. A diversity of actors – policy makers, regulators, water companies, non-governmental organisations and consumers – have a role in this process. This differs from jurisdiction to jurisdiction, and legacies and path dependencies play a major role in how public water supply is institutionalised in a country.

Water governance faces challenges such as population growth, rapid urbanisation and land use changes. Climate change and its projected effects will exacerbate this. Some regions will have more water, and others less. Increasing populations will lead to questions about access and allocation. A key issue is uncertainty: we simply do not know if and when the projected effects of climate change will happen, and to what extent.

In the context of climate change, the term ‘adaptive water governance’ is frequently used. What this means is that water governance needs to be flexible in order to adapt to uncertainties. Legislation and policies should not be set in stone, but reviewed at regular intervals to account for the latest research results or practical experiences. In some cases we need to be able to overcome current water policies and opt for new approaches. Cape Town’s threat of a “day-zero” in 2018, where all taps would be turned off, led to drastic policy changes, which subsequently led to massive reductions in daily water consumption by the general public and businesses.

Flexibility also means to cater for the different projected impacts of climate change across the world. This includes taking into account geographical, regional, social and cultural characteristics, and should result in tailor-made adaptation strategies. Public participation from the very beginning of a process, and not just to legitimise the outcome, should be an inherent part of adaptive water governance. Unfortunately, the latter is also one of the greatest challenges. Who are the stakeholders who should take part? Do they have enough staff and financial resources at their disposal?

Another key issue to overcome is the “silo-mentality” we still find in environmental governance. While the scientific consensus is clear about the need to look at an issue like water in an integrated way, in reality we often find a “silo-mentality”. This refers to the non-collaboration across policy sectors, for instance among water, urban planning, agriculture and energy. Even within water governance, we often find that flooding and drought policy teams operate separately from each other and are not looking at the issue from an integrated perspective.

Water governance is a challenging task, but there are many positive and promising examples, policies, and approaches available. Some great examples are the catchment-based-approaches, which look at a river catchment as a whole. Or in the Netherlands we find “water-squares”, public places shaped like a bath tub that function both as a playground and as a retention area for overflow water after a heavy rain event. It is those co-benefits, being good for climate change adaptation as well as fulfilling another function such as recreation, creating jobs, or restoring wildlife, that are key.

We do not only drink water, but we swim in water, we sail or row on water, we walk along rivers, canals and lakes. We cherish water in various ways, but often neglect its social and cultural value at the same time. Tackling this is a key challenge for water governance in the future.

Kevin Grecksch is a British Academy Postdoctoral Fellow at the Centre for Socio-Legal Studies in the Faculty of Law. He is a social scientist who specialises in water governance and climate change adaptation. 

Professor John Goodenough

Kindly reproduced from The Royal Society website

Professor John Goodenough from the Cockrell School of Engineering at The University of Texas at Austin has been awarded the Royal Society’s Copley Medal, the world’s oldest scientific prize. Already a fellow of the Royal Society, Goodenough is being honoured for his exceptional contributions to materials science, including his discoveries that led to the invention of the rechargeable lithium battery—used in devices like laptops and smartphones worldwide.

As the latest recipient of the Royal Society’s premier award, Professor Goodenough joins an elite group of men and women, such as Benjamin Franklin, Charles Darwin, Louis Pasteur, Albert Einstein and Dorothy Hodgkin, who have been awarded the Copley Medal for their exceptional contributions to science and engineering in the past.

Venki Ramakrishnan, President of the Royal Society, said, “Professor Goodenough has a rich legacy of contributions to materials science in both a fundamental capacity, with his defining work on the properties of magnetism, to a widely applicable one, with his ever-advancing work on batteries, including those powering the smartphone in your very pocket. The Royal Society is delighted to recognise his achievements with the Copley Medal, our most prestigious prize.”

On hearing the news, Professor Goodenough said, “Words are not sufficient to express my appreciation for this award. My ten years at Oxford were transformative for me, and I thank especially those who had the imagination to invite a U.S. non-academic physicist to come to England to be a Professor and Head of the Oxford Inorganic Chemistry Laboratory. I regret that age and a bad leg prevent my travel back to England to celebrate such a wonderful surprise.”

Professor Goodenough is currently serving as the Virginia H. Cockrell Centennial Chair in Engineering at The University of Texas at Austin, where he continues to work on new battery technology. Though his lithium-ion breakthrough provided a reliable, rechargeable battery, it is, at the same time, weak, expensive and flammable—shortcomings Professor Goodenough aims to overcome with his latest work on solid-state batteries.

Innovations in battery technology, such as the lithium-ion-based model, helped liberate society from its reliance on cables. Professor Goodenough now aims to develop technology with an even bolder end goal: to liberate society from its dependence on fossil fuels.

He began his research career in 1952 at the Massachusetts Institute of Technology’s (MIT) Lincoln Laboratory where he was part of a team that developed random-access magnetic memory (RAM) – a technology still used in digital computing. Building on this experience, he authored ‘Magnetism and the Chemical Bond’, a treatise and modern-day classic textbook on the behaviour of magnetic interactions. He helped lay the foundations for developing a set of rules for predicting signs of super-exchange interactions in solids, known as the Goodenough-Kanamori rules.

After his time at MIT, Professor Goodenough led the University of Oxford’s Inorganic Chemistry Laboratory. His research focused on the implementation of lithium as a potential cathode material for batteries – pioneering work that was to form the basis for the first commercial lithium-ion battery, still used in mobile electronics all around the world. In 1986 his curiosity and expertise drew him to a position at the Cockrell School of Engineering at UT Austin, where he has remained ever since.

The Copley Medal was first awarded by the Royal Society in 1731, 170 years before the first Nobel Prize. It is awarded for outstanding achievements in scientific research. In recent years, recipients include eminent scientists such as Peter Higgs, the physicist who hypothesised the existence of the Higgs Boson, as well as DNA fingerprinting pioneer Alec Jeffreys, and Andre Geim, who discovered graphene. Last year’s winner, Professor Jeffrey Gordon, was honoured for his contributions to understanding the role of gut microbial communities to human health and disease.