The researchers, from Cambridge, Southampton and Cardiff Universities in the UK and the Skolkovo Institute of Science and Technology in Russia, have used quantum particles known as polaritons – which are half light and half matter – to act as a type of ‘beacon’ showing the way to the simplest solution to complex problems. This entirely new design could form the basis of a new type of computer that can solve problems that are currently unsolvable, in diverse fields such as biology, finance or space travel. The results are reported in the journal Nature Materials.

Our technological progress — from modelling protein folding and behaviour of financial markets to devising new materials and sending fully automated missions into deep space — depends on our ability to find the optimal solution of a mathematical formulation of a problem: the absolute minimum number of steps that it takes to solve that problem.

The search for an optimal solution is analogous to looking for the lowest point in a mountainous terrain with many valleys, trenches, and drops. A hiker may go downhill and think that they have reached the lowest point of the entire landscape, but there may be a deeper drop just behind the next mountain. Such a search may seem daunting in natural terrain, but imagine its complexity in high-dimensional space. “This is exactly the problem to tackle when the objective function to minimise represents a real-life problem with many unknowns, parameters, and constraints,” said Professor Natalia Berloff of Cambridge’s Department of Applied Mathematics and Theoretical Physics and the Skolkovo Institute of Science and Technology, and the paper’s first author.

Modern supercomputers can only deal with a small subset of such problems when the dimension of the function to be minimised is small or when the underlying structure of the problem allows it to find the optimal solution quickly even for a function of large dimensionality. Even a hypothetical quantum computer, if realised, offers at best the quadratic speed-up for the “brute-force” search for the global minimum.

Berloff and her colleagues approached the problem from an unexpected angle: What if instead of moving along the mountainous terrain in search of the lowest point, one fills the landscape with a magical dust that only shines at the deepest level, becoming an easily detectible marker of the solution?

“A few years ago our purely theoretical proposal on how to do this was rejected by three scientific journals,” said Berloff. “One referee said, ‘Who would be crazy enough to try to implement this?!’ So we had to do it ourselves, and now we’ve proved our proposal with experimental data.”

Their ‘magic dust’ polaritons are created by shining a laser at stacked layers of selected atoms such as gallium, arsenic, indium, and aluminium. The electrons in these layers absorb and emit light of a specific colour. Polaritons are ten thousand times lighter than electrons and may achieve sufficient densities to form a new state of matter known as a Bose-Einstein condensate, where the quantum phases of polaritons synchronise and create a single macroscopic quantum object that can be detected through photoluminescence measurements.

The next question the researchers had to address was how to create a potential landscape that corresponds to the function to be minimised and to force polaritons to condense at its lowest point. To do this, the group focused on a particular type of optimisation problem, but a type that is general enough so that any other hard problem can be related to it, namely minimisation of the XY model which is one of the most fundamental models of statistical mechanics. The authors have shown that they can create polaritons at vertices of an arbitrary graph: as polaritons condense, the quantum phases of polaritons arrange themselves in a configuration that correspond to the absolute minimum of the objective function.

“We are just at the beginning of exploring the potential of polariton graphs for solving complex problems,” said co-author Professor Pavlos Lagoudakis, Head of the Hybrid Photonics Lab at the University of Southampton and the Skolkovo Institute of Science and Technology, where the experiments were performed. “We are currently scaling up our device to hundreds of nodes, while testing its fundamental computational power. The ultimate goal is a microchip quantum simulator operating at ambient conditions.”

Reference:
Natalia G. Berloff et al. ‘Realizing the classical XY Hamiltonian in polariton simulators.’ Nature Materials (2017). DOI: 10.1038/nmat4971

This week, UK Universities and Science Minister Jo Johnson signed the agreement with the US Energy Department to invest the sum in the Long-Baseline Neutrino Facility (LBNF) and the Deep Underground Neutrino Experiment (DUNE). DUNE will study the properties of mysterious particles called neutrinos, which could help explain more about how the universe works and why matter exists at all.

This latest investment is part of a long history of UK research collaboration with the US, and is the first major project of the wider UK-US Science and Technology agreement.

On signing the agreement in Washington DC, UK Science Minister, Jo Johnson said: “Our continued collaboration with the US on science and innovation is beneficial to both of our nations and through this agreement we are sharing expertise to enhance our understanding of many important topics that have the potential to be world changing.

“The UK is known as a nation of science and technical progress, with research and development being at the core of our industrial strategy.  By working with our key allies, we are maintaining our position as a global leader in research for years to come.”

“The international DUNE collaboration came together to realise a dream of a game-changing program of neutrino science; today’s announcement represents a major milestone in turning this dream into reality,” said Professor Thomson. “This UK investment in fundamental science will enable us to deliver critical systems to the DUNE experiment and to provide new opportunities for the next generation of scientists to work at the forefront of science and technology.”

This investment is a significant step which will secure future access for UK scientists to the international DUNE experiment. Investing in the next generation of detectors, like DUNE, helps the UK to maintain its world-leading position in science research and continue to develop skills in new cutting-edge technologies.

The UK’s Science and Technology Facilities Council (STFC) will manage the UK’s investment in the international facility, giving UK scientists and engineers the chance to take a leading role in the management and development of the DUNE far detector and the LBNF beam line and associated PIP-II accelerator development.

Accompanying Jo Johnson on the visit to the US, Chief Executive Designate at UK Research and Innovation, Sir Mark Walport said: “Research and innovation are global endeavours. Agreements like the one signed today by the United Kingdom and the United States set the framework for the great discoveries of the future, whether that be furthering our understanding of neutrinos or improving the accessibility of museum collections.

“Agreements like this also send a clear signal that UK researchers are outward looking and ready to work with the best talent wherever that may be. UK Research and Innovation is looking forward to extending partnerships in science and innovation around the world.”

DUNE will be the first large-scale US-hosted experiment run as a truly international project at the inter-governmental level, with more than 1,000 scientists and engineers from 31 countries building and operating the facility, including many from the UK.  The US is meeting the major civil construction costs for conventional facilities, but is seeking international partners to design and build major elements of the accelerator and detectors.  The total international partner contributions to the entire project are expected to be about $500M.

The UK research community is already a major contributor to the DUNE collaboration, with 14 UK universities and two STFC laboratories providing essential expertise and components to the experiment and facility. This ranges from the high-power neutrino production target, the readout planes and data acquisitions systems to the reconstruction software.

Dr Brian Bowsher, Chief Executive of STFC, said:“This investment is a significant and exciting step for the UK that builds on UK expertise.

“International partnerships are the key to building these world-leading experiments, and the UK’s continued collaboration with the US, through STFC, demonstrates that we are the science partner of choice in such agreements.

“I am looking forward to seeing our scientists work with our colleagues in the US in developing this experiment and the exciting science which will happen as a result.”

One aspect DUNE scientists will look for is the differences in behaviour between neutrinos and their antimatter counterparts, antineutrinos, which could give us clues as to why we live in a matter-dominated universe – in other words, why we are all here, instead of having been annihilated just after the Big Bang. DUNE will also watch for neutrinos produced when a star explodes, which could reveal the formation of neutron stars and black holes, and will investigate whether protons live forever or eventually decay, bringing us closer to fulfilling Einstein’s dream of a grand unified theory.

The DUNE experiment will attract students and young scientists from around the world, helping to foster the next generation of leaders in the field and to maintain the highly skilled scientific workforce worldwide.

The Cambridge team is playing a leading role in the development of the advanced pattern recognition and computational techniques that will be needed to interpret the data from the vast DUNE detectors.

Other than Cambridge, the UK universities involved in the project are Birmingham, Bristol, Durham, Edinburgh, Imperial, Lancaster, Liverpool, UCL, Manchester, Oxford, Sheffield, Sussex and Warwick.

Adapted from an STFC press release. 

The study, which investigated photovoltaic devices based on a type of materials called perovskites, suggests that these could achieve unprecedented levels of super-efficiency. But to do so, they will need to turn sunlight into electrons and then extract these as electrical charge within just quadrillionths of a second – a few “femtoseconds”, to give them their scientific name.

Moving electrons at this ultrafast rate would enable the creation of “hot carrier” cells. These are solar cells which can generate electricity more efficiently by making use of the added kinetic energy that electrons have for a brief moment just after they are created, while they are moving at high speed.

The amount of electrical energy that can be extracted from a hot carrier cell, relative to the amount of light absorbed, could potentially match or even break an energy efficiency rate of 30%. In rough terms, this is the maximum energy efficiency that solar cells can conceivably  achieve – although standard silicon cells typically have efficiencies closer to 20% in practice.

Despite the minuscule fractions of time involved, the authors of the new paper say that it is possible that perovskites could ultimately push this efficiency barrier.

The study, published in the journal Nature Communications, was carried out by academics in Italy and the UK. The British team involved researchers in the Cavendish Laboratory’s Optoelectronics research group of Professor Sir Richard Friend, a Fellow of St John’s College, Cambridge. The Italian team are based at the Politecnico di Milano in the group of Professor Guilio Cerullo.

Johannes Richter, a PhD student in the Optoelectronics group and the paper’s lead author, said: “The timescale that we calculated is now the time limit that we have to operate within if we want to create super-efficient, hot carrier solar devices. We would need to get electrons out before this tiny amount of time elapses.”

“We are talking about doing this extremely quickly, but it’s not impossible that it could happen. Perovskite cells are very thin and this gives us hope, because the distance that the electrons have to cover is therefore very short.”

Perovskites are a class of materials which could before long replace silicon as the material of choice for many photovoltaic devices. Although perovskite solar cells have only been developed within the past few years, they are already almost as energy-efficient as silicon.

Partly because they are considerably thinner, they are much cheaper to make. While silicon cells are about a millimetre thick, perovskite equivalents have a thickness of approximately one micrometre, about 100 times thinner than a human hair. They are also very flexible, meaning that in addition to being used to power buildings and machines, perovskite cells could eventually be incorporated into things like tents, or even clothing.

In the new study, the researchers wanted to know for how long the electrons produced by these cells retain their highest possible levels of energy. When sunlight hits the cell, light particles (or photons), are converted into electrons. These can be drawn out through an electrode to harvest electrical charge.

For a brief moment after they are created, the electrons are moving very quickly. However, they then start to collide, and lose energy. Electrons which retain their speed, prior to collision, are known as “hot” and their added kinetic energy means that they have the potential to produce more charge.

“Imagine if you had a pool table and each ball was moving at the same speed,” Richter explained. “After a certain amount of time, they are going to hit each other, which causes them to slow down and change direction. We wanted to know how long we have to extract the electrons before this happens.”

The Cambridge team took advantage of a method developed by their colleagues in Milan called two dimensional spectroscopy. This involves pumping light from two lasers on to samples of lead iodide perovskite cell in order to simulate sunlight, and then using a third “probe” laser to measure how much light is being absorbed.

Once the electrons have collided and slowed down, and are thus starting to take up space in the cell, the amount of light being absorbed changes. The time it took for this to happen in the study effectively allowed the researchers to establish how much time is available to extract electrons while they are still “hot”.

The study found that electron collision events started to happen between 10 and 100 femtoseconds after light was initially absorbed by the cell. To maximise energy efficiency, the electrons would thus need to reach the electrode in as little as 10 quadrillionths of a second.

The researchers are nonetheless optimistic that this might be possible. As well as taking advantage of the intrinsic thinness of perovskite, they believe that nanostructures could be created within the cells to reduce further the distance that the electrons need to travel.

“That approach is just an idea for now, but it is the sort of thing that we would require in order to overcome the very small timescales that we have measured,” Richter added.

The paper, Ultrafast carrier thermalization in lead iodide perovskite probed with two-dimensional electronic spectroscopy, is published in Nature Communications.

The team used genome editing techniques to stop a key gene from producing a protein called OCT4, which normally becomes active in the first few days of human embryo development. After the egg is fertilised, it divides until at about 7 days it forms a ball of around 200 cells called the ‘blastocyst’. The study found that human embryos need OCT4 to correctly form a blastocyst.

“We were surprised to see just how crucial this gene is for human embryo development, but we need to continue our work to confirm its role” says Dr Norah Fogarty from the Francis Crick Institute, first author of the study. “Other research methods, including studies in mice, suggested a later and more focussed role for OCT4, so our results highlight the need for human embryo research.”

Dr Kathy Niakan from the Francis Crick Institute, who led the research adds, “One way to find out what a gene does in the developing embryo is to see what happens when it isn’t working. Now we have demonstrated an efficient way of doing this, we hope that other scientists will use it to find out the roles of other genes. If we knew the key genes that embryos need to develop successfully, we could improve IVF treatments and understand some causes of pregnancy failure. It will take many years to achieve such an understanding, our study is just the first step.”

The research was published in Nature and led by scientists at the Francis Crick Institute, in collaboration with colleagues at Cambridge University, Oxford University, the Wellcome Trust Sanger Institute, Seoul National University and Bourn Hall Clinic. It was chiefly funded by the UK Medical Research Council, Wellcome and Cancer Research.

The team spent over a year optimising their techniques using mouse embryos and human embryonic stem cells before starting work on human embryos. To inactivate OCT4, they used an editing technique called CRISPR/Cas9 to change the DNA of 41 human embryos. After seven days, embryo development was stopped and the embryos were analysed.

The embryos used in the study were donated by couples who had undergone IVF treatment, with frozen embryos remaining in storage; the majority were donated by couples who had completed their family, and wanted their surplus embryos to be used for research. The study was done under a research licence and strict regulatory oversight from the Human Fertilisation and Embryology Authority (HFEA), the UK Government’s independent regulator overseeing infertility treatment and research.

As well as human embryo development, OCT4 is thought to be important in stem cell biology. ‘Pluripotent’ stem cells can become any other type of cell, and they can be derived from embryos or created from adult cells such as skin cells. Human embryonic stem cells are taken from a part of the developing embryo that has high levels of OCT4.

“We have the technology to create and use pluripotent stem cells, which is undoubtedly a fantastic achievement, but we still don’t understand exactly how these cells work,” explains Dr James Turner, co-author of the study from the Francis Crick Institute. “Learning more about how different genes cause cells to become and remain pluripotent will help us to produce and use stem cells more reliably.”

Sir Paul Nurse, Director of the Francis Crick Institute, says: “This is exciting and important research. The study has been carried out with full regulatory oversight and offers new knowledge of the biological processes at work in the first five or six days of a human embryo’s healthy development. Kathy Niakan and colleagues are providing new understanding of the genes responsible for a crucial change when groups of cells in the very early embryo first become organised and set on different paths of development. The processes at work in these embryonic cells will be of interest in many areas of stem cell biology and medicine.”

Dr. Kay Elder, study co-author from the Bourn Hall Clinic, says: “Successful IVF treatment is crucially dependent on culture systems that provide an optimal environment for healthy embryo development. Many embryos arrest in culture, or fail to continue developing after implantation; this research will significantly help treatment for infertile couples, by helping us to identify the factors that are essential for ensuring that human embryos can develop into healthy babies.”

Dr Ludovic Vallier, co-author on the study from the Wellcome Trust Sanger Institute and the Wellcome – MRC Cambridge Stem Cell Institute, said: “This study represents an important step in understanding human embryonic development. The acquisition of this knowledge will be essential to develop new treatments against developmental disorders and could also help understand adult diseases such as diabetes that may originate during the early stage of life. Thus, this research will open new fields of opportunity for basic and translational applications.”

Reference:
Norah M.E. Fogarty et al. ‘Genome editing of OCT4 reveals distinct mechanisms of lineage specification in human and mouse embryos.’ Nature (2017). DOI: 10.1038/nature24033.

Adapted from a Francis Crick Institute press release. 

In an article published today in the Journal of Public Mental Health, the team discuss the policy implications of their study published earlier in the year, which found that young people who have contact with mental health services in the community and in clinics are significantly less likely to suffer from clinical depression later in their adolescence than those with equivalent difficulties who do not receive treatment.

Young people’s mental health problems are associated with an increased risk of problems later on in adulthood, including poor mental health, lower income, unemployment, inability to maintain a stable cohabiting relationship, and greater contact with the criminal justice system. However, the team’s previous study suggested that access for adolescents with mental health problems to intervention in schools and clinics reduces mental health problems up to three years later and would therefore yield personal, economic, and societal benefits over an individual’s lifespan.

In the study, Sharon Neufeld and colleagues from the Department of Psychiatry at the University of Cambridge used data obtained between 2005-2010 – prior to funding cuts to Child and Adolescent Mental Health Services in the community and in NHS clinics. Between 2008 and 2013, funding for the services dropped by 5.4 per cent in real terms so that in 2012/2013, only 6 per cent of the NHS’ total mental health budget was spent on these services. The knock-on effect of this was that while in 2005/2006, 38% of 14-year olds with a mental disorder had made contact with mental health provision for young people in the past year, in 2014/2015 only 25% of all children and young people with a mental disorder had made such service contact.

One consequence of this has been that the number of young people attending A&E due to a psychiatric condition had doubled by 2014/2015, compared with 2010/2011.

“It’s important to improve young people’s mental health services in schools and strengthen the care pathway to  specialist Child and Adolescent Mental Health Services, in order to meet the NHS target of returning contact back up to 35% by 2020/2021,” says Mrs Neufeld.

“We need to acknowledge the mental health suffering in our young people that has only been increasingly apparent in recent years, and resolve to improve young people’s access to effective mental health services.”

She and her colleagues argue that as well as protecting funding for specialist Child and Adolescent Mental Health Services, funding for school-based counselling is also important as their study found that this was the second most used service for young people with a mental health disorder.

“The current government has promised to provide funding for mental health first aid training for teachers in secondary schools, which should enable them to better identify those with mental health issues and connect students to the appropriate support services,” says Professor Peter Jones. “But this is against a backdrop of freezing school budgets, the very budgets that typically fund school-based counselling.

“Funding for school-based counselling must be ring-fenced, whether it be funded through the education sector or NHS, to ensure young people have adequate service access prior to specialist mental health services.”

The researchers also argue that GPs could use more training in identifying mental disorder. The Royal College of General Practitioners reports that nine out of ten people with mental health problems are managed in primary care. However, even in the recent past, most GPs do not include a rotation in mental illness as part of their training. Such gaps in training, say the researchers, mean that GPs correctly identify less than a half (47%) of depression cases.

“This is a huge missed opportunity,” adds Professor Ian Goodyer. “GPs will encounter a large number of individuals with mental disorders, but have insufficient background knowledge to appropriately identify such cases.”

Reference
Sharon AS Neufeld, Peter B Jones and Ian M. Goodyer. Child and adolescent mental health services: longitudinal data sheds light on current policy for psychological interventions in the community.  Journal of Public Mental Health; Date; DOI 10.1108/JPMH-03-2017-0013

For the first time, archaeologists have uncovered and carefully documented an intact burial in a monumental chamber tomb of the Mycenaean palatial period, around 3,350 years ago. Research into the material uncovered has only just begun but the discovery will expand our knowledge of Mycenaean funerals – from the treatment of the body to the selection of objects placed for burial.

The tomb is approached by an impressive rock-cut passageway, 20 m long, which leads to a deep façade some 5.40 m in height. A doorway gives access to the burial chamber. Its area of 42 sq m makes this the ninth largest known to date out of 4,000 examples excavated in the last 150 years in Greece. The partial collapse of the original chamber roof has helped to preserve the burial layer intact.

“Mycenaean chamber tombs are generally found by archaeologists to have been disturbed or looted. Most contain many burials, making an association between individual people and objects very difficult or impossible,” said Dr Yannis Galanakis of Cambridge’s Faculty of Classics, co-director of the five-year Prosilio project and an expert in Aegean archaeology.

“Finding an intact burial, let alone in a monumental tomb of the palatial period, 1370-1200 BC, makes our discovery all the more special for the knowledge we can now acquire about the tomb-using group and the practices they performed during and after the funeral.”

Once huge quantities of soil and rubble had been carefully excavated, the archaeologists found in the chamber the remains of a man, aged 40 to 50 years. He was accompanied by a selection of fine objects: jewellery made in a range of materials, combs, pins, a pair of horse bits, arrowheads, a bow, a sealstone, a signet ring, and a group of tinned clay vessels of various shapes.

“The size and quality of construction of the tomb correlates well with the discovered objects, all of which speak of a man from the upper echelons of the local society,” said Galanakis.

“Initial examination of the finds suggests a conscious selection by the tomb-using group responsible for the burial’s preparation of the objects interred with the body. The impression we get is that the tomb was built during the man’s life. It is indeed astonishing, and a very rare instance, to be able to excavate the remains of the man for whom the tomb must have been constructed.”

Galanakis was struck by the placement of different shapes and types of jewellery with a male burial, which challenges the commonly held assumption that jewellery in Mycenaean Greece should be chiefly associated with female burials. “It also chimes with the discovery of considerable quantities of jewellery by the University of Cincinnati in 2015 in the burial of the ‘griffin warrior’ at Pylos, which is older by a century than that of the man at Prosilio.”

Striking too is the absence of painted pottery, with the exception of two painted stirrup jars, often taken to contain aromatic oils and which may be associated with the final use and closure of the tomb around 1300 BC. Painted pottery is very common in Mycenaean tombs. Its absence from the initial burial is further confirmation of the conscious choices made in the selection of objects placed alongside this man’s burial at Prosilio.

The Prosilio team believes that this monumental structure, known as tomb 2, is associated with ancient Orchomenos, a major centre which controlled northern Boeotia, a region of Greece. Orchomenos, which is only 3.5 km away, oversaw in the 14th and 13th centuries BC the partial drainage of Lake Kopaïs – once the largest lake in Greece – a project that yielded a sizeable area of land for agriculture.

At its peak (1350-1250 BC), Orchomenos’s power is reflected in its most famous monument, the tholos tomb ‘of Minyas’, first excavated by Heinrich Schliemann in the 19th century and comparable only in size and refinement to the tholos tomb ‘of Atreus’ at Mycenae.

“Despite the tholos ‘of Minyas’ and some earlier important discoveries by Greek and German teams in the area, we still know very little about ancient Orchomenos. We hope that the continuation of our project will help us understand better Orchomenos’s position in the region and learn more about its population and their practices,” said Galanakis.

“The discovery this year enables us to ask questions such as why certain objects were selected for burial while others were not – and what kind of rituals were performed as part of funerary and post-funerary practices. The finds will spark new discussions about the role of burials in Mycenaean life during the palatial period.”

The five-year Prosilio project is in its first year. In subsequent years, the team aims to excavate more tombs and study and publish the archaeological data collected. The initiative is a collaboration between the Ephorate of Antiquities of Boeotia and the British School at Athens. Its directors are Dr Alexandra Charami (Director of the Ephorate of Antiquities of Boeotia) and Dr Yannis Galanakis, (Senior Lecturer in the Faculty of Classics and Director of the Museum of Classical Archaeology, University of Cambridge).

The Prosilio team also includes Kyriaki Kalliga, archaeologist of the Ephorate of Antiquities of Boeotia, Dr Panagiotis Karkanas, geo-archaeologist and Director of the Wiener Laboratory at the American School of Classical Studies in Athens, Dr Ioanna Moutafi, bio-archaeologist and senior researcher at the Wiener Laboratory, Emily Wright, field supervisor and PhD candidate in Archaeology at the University of Cambridge, and Professor Ann Brysbaert of the University of Leiden and Principal Investigator of the ERC project SETinSTONE. Some 25 students, specialists and workers helped in this year’s fieldwork.

The Prosilio project was conducted with permission from the Hellenic Ministry of Culture & Sports and Ioannis Papadopoulos, the owner of the land. The project was generously funded by, among other sources, the University of Cambridge (Faculty of Classics, the McDonald Institute, the Cambridge Humanities Research Grant scheme, and Sidney Sussex College), the Institute for Aegean Prehistory (INSTAP) and the British School at Athens.

Inset images: entrance to Prosilio tomb 2; horse bits found with the burial (Yannis Galanakis).

Leprosy is an infectious disease that affects the skin and peripheral nerves and is caused by Mycobacterium leprae and, less commonly, Mycobacterium lepromatosis. According to the World Health Organization, there has been a dramatic decrease in the global disease burden in the past few decades: from 5.2 million people with leprosy in 1985 to 176,176 at the end of 2015.

Despite the disease having been known about for thousands of years – many people will have first heard about it through references in the Bible – very little is understood about its biology. This is in part because the bacteria are difficult to grow in culture and there are no good animal models: M. leprae can grow in the footpads of mice, but do not cause nerve damage; the disease causes nerve damage in armadillos, but these animals are rarely used in research.

Now, an international team led by researchers at the University of Cambridge, UK, and the University of Washington, the University of California Los Angeles and Harvard University, USA, have used a new animal model, the zebrafish, to show for the first time how M. leprae damage nerves by infiltrating the very cells that are meant to protect us. Zebrafish are already used to study another species of mycobacteria, to help understand tuberculosis (TB).

Scientists have previously shown that the nerve damage in leprosy is caused by a stripping away of the protective insulation, the myelin sheath, that protects nerve fibres, but it was thought that this process occurred because the bacteria got inside Schwann cells, specialist cells that produce myelin.

In new research published today in the journal Cell, researchers used zebrafish that had been genetically modified so that their myelin is fluorescent green; young zebrafish are themselves transparent, and so the researchers could more easily observe what was happening to the nerve cells. When they injected bacteria close to the nerve cells of the zebrafish, they observed that the bacteria settled on the nerve, developing donut-like ‘bubbles’ of myelin that had dissociated from the myelin sheath.

When they examined these bubbles more closely, they found that they were caused by M. leprae bacteria inside of macrophages – literally ‘big eaters’, immune cells that consume and destroy foreign bodies and unwanted material within the body. But, as is also often the case with TB, the M. leprae was consumed by the macrophages but not destroyed.

“These ‘Pac-Man’-like immune cells swallow the leprosy bacteria, but are not always able to destroy them,” explains Professor Lalita Ramakrishnan from the Department of Medicine at the University of Cambridge, whose lab is within the Medical Research Council’s Laboratory of Molecular Biology. “Instead, the macrophages – which should be moving up and down the nerve fibre repairing damage – slow down and settle in place, destroying the myelin sheath.”

Professor Ramakrishnan working with Dr Cressida Madigan, Professor Alvaro Sagasti, and other colleagues confirmed that this was the case by knocking out the macrophages and showing that when the bacteria sit directly on the nerves, they do not damage the myelin sheath.

The team further demonstrated how this damage occurs. A molecule known as PGL-1 that sits on the surface of M. leprae ‘reprograms’ the macrophage, causing it to overproduce a potentially destructive form of the chemical nitric oxide that damages mitochondria, the ‘batteries’ that power nerves.

“The leprosy bacteria are, essentially, hijacking an important repair mechanism and causing it to go awry,” says Professor Ramakrishnan. “It then starts spewing out toxic chemicals. Not only does it stop repairing damage, but it creates more damage itself.”

“We know that the immune system can lead to nerve damage – and in particular to the myelin sheath – in other diseases, such as multiple sclerosis and Guillain–Barré syndrome,” says Dr Cressida Madigan from the University of California, Los Angeles. “Our study appears to place leprosy in the same category of these diseases.”

The researchers say it is too early to say whether this study will lead to new treatments. There are several drugs being tested that inhibit the production of nitric oxide, but, says Professor Ramakrishnan, the key may be to catch the disease at an early enough stage to prevent damage to the nerve cells.

“We need to be thinking about degeneration versus regeneration,” she says. “At the moment, leprosy can be treated by a combination of drugs. While these succeed in killing the bacteria, once the nerve damage has been done, it is currently irreversible.  We would like to understand how to change that. In other words, are we able to prevent damage to nerve cells in the first place and can we additionally focus on repairing damaged nerve cells?”

The research was funded by the National Institutes of Health, the Wellcome Trust, and the AP Giannini Foundation.

Reference
Madigan, CA et al. A Macrophage Response To Mycobacterium leprae Phenolic Glycolipid Initiates Nerve Damage In Leprosy. Cell; 24 Aug 2017; DOI: 10.1016/j.cell.2017.07.030

A new analysis by Cambridge and Oxford sociologists indicates that some 4.6 million people in the UK regularly experience ‘precarious scheduling’: flexible working with limited hours dictated by management, often with little notice, and to the detriment of employees’ home lives and mental health.

Researchers say this damaging approach to flexible work is common among supermarket and care home workers, for example, with precarious scheduling affecting 3.9 million more than just those on zero-hours contracts.

In fact, they describe zero-hours as merely the “tip of the iceberg” of precarious employment practices – as any contract with minimal guaranteed hours subject to last minute changes and reductions offers very little security.

This can leave workers in a degrading relationship with managers: begging for schedule changes to accommodate commitments such as childcare, and competing to become management ‘favourites’ in the hope of additional hours – often hours originally promised to them.

Dr Alex Wood, now at Oxford University, embedded himself as a shelf-stacker at a UK supermarket while a researcher at Cambridge’s Department of Sociology. He experienced first-hand the toxic interactions between shop management and the insecure – at times desperate – workers whose lives are controlled through scheduling.

Together with Cambridge collaborator Dr Brendan Burchell, Wood has now interrogated data from three rounds of the European Working Conditions Survey (EWCS) – undertaken across Europe every five years by EU agency EuroFound, most recently in 2015.

Using data from the last EWCS, the pair found that 14.7% of all surveyed UK workers routinely experienced manager-controlled alterations to their schedules – often at very short notice. They say that, when scaled up, this percentage equates to 4.6 million people experiencing some form of precarious scheduling in the UK.

The researchers’ EWCS analysis is published today (16 August) in a blog post, as is Wood’s latest Cambridge study of supermarket staff living with precarious scheduling, in the journal Work, Employment & Society.

“Manager-controlled flexible scheduling causes a huge amount of stress and anxiety for workers who are unable to plan their lives socially or financially as a result,” says Burchell, from Cambridge’s Department of Sociology.

“The practice is both toxic and endemic in many UK sectors such as care and retail. Government reviews need to look far beyond just zero-hours contracts.”

“The key issue is not simply the lack of any guaranteed hours. The employment contracts of millions offer little security around the hours they will be told to work in a given day, week or month, and how much notice they are given.”

The EWCS data includes surveys conducted in 2005, 2010 and 2015. The recent peak of precarious scheduling in the UK was 2010, with 18.4% of those surveyed. Wood suggests that reduced unemployment since 2010 may mean slightly less pressure to take precarious and unpredictable jobs with limited hours.

“The past decade has seen a fragmenting of working time, as firms have saved costs by increasing shift flexibility through a variety of mechanisms,” says Wood, now at Oxford’s Internet Institute.

“These mechanisms include short- and zero-hour contracts, the emergence of ‘gig economy’ platforms, and flexible contracts that guarantee a minimum number of hours but no fixed scheduling pattern.

“Seven years of austerity have placed the public sector under pressure to contain labour costs through shift flexibility. Those who have challenging schedules imposed on them at short notice are likely to experience worse mental health, typified by anxiety and feeling low,” says Wood.

During his supermarket fieldwork, Wood observed how workers were frequently expected to extend or change shifts with little or no notice – causing the majority to feel negatively about their jobs.

The latest study, out today, describes how control exerted by managers through flexible scheduling creates an environment where workers must constantly strive to maintain managers’ favour.

In one London store, he witnessed managers encouraging workers to “beg them for additional hours” by making vague promises that more hours would be available.

“Staff were told ‘I always have some overtime so let me know if you want any’. This was despite my entire work team being employed on less than nine hours a week and all desiring more hours or full time work,” says Wood.

One UK worker, Jackie, told Wood: “It’s strange because you speak to the staff and they say their department is short [of staff] but when you ask the manager they say ‘there isn’t any at the moment but keep putting your name down for overtime’. I’m just getting a few hours here and there.”

Wood also observed managers cutting hours – affecting worker income – at short notice and altering schedules to clash with childcare and education. Some staff would often work unpaid overtime just to stay in management good books.

“Managers plead innocence, and that staffing needs are set by head office. This was frequently disbelieved. Many workers felt punished, but it was impossible for them to know for sure – adding to the insecurity,” he says.

The first domestic abuse policing strategy in UK history to be trialled under experimental conditions has found that an inexpensive two-day course in behaviour management for first offenders resulted in 35% fewer men reoffending against their partner, and reduced further harm to victims by over a quarter.

Researchers at Cambridge University’s Institute of Criminology worked with Hampshire Constabulary to conduct the study using the recently developed CARA (Cautions and Relationship Abuse) programme: small-group discussion workshops for men who received conditional cautions for first arrests for low-harm domestic abuse.

The researchers say that, in just this initial study of hundreds of Southampton-area offenders over a 12-month period, the CARA programme prevented significant harm to victims, hundreds of prison days, and consequently saved thousands of pounds.

The findings are published in full in this week’s print edition of the Cambridge Journal of Evidence-Based Policing.

The team behind the study say that several police forces want to replicate the use of the CARA course, developed by the Hampton Trust domestic abuse charity. However, they say that current guidance from the Crown Prosecution Service restricts the use of conditional cautions for domestic abuse across the country.

“Dealing with high volumes of low-harm common assault cases against intimate partners is a significant issue for police forces across the UK, particularly in times of continued austerity,” said study lead author Professor Heather Strang, Director of Research at Cambridge’s Jerry Lee Centre for Experimental Criminology.

“No other programme to our knowledge now has such strong evidence of yielding a substantial reduction in harm to victims of domestic abuse.

“The CARA programme should be approved for general use with low-harm first offenders, preferably with further randomised trials to ensure it works for different communities across England and Wales.”

The study only involved adult men who admitted their offence, were not judged ‘high risk’, and had no record of any violence in the preceding two years. All victims agreed to their partners’ participation.

To be eligible for the experiment, the offence had to be classified as either common assault/battery, criminal damage, harassment, threatening behaviour, or domestic theft.

Of the 293 offenders who fit the strict criteria between August 2012 and November 2015, around half were randomly assigned to attend CARA workshops, run by experienced facilitators from the Southampton-based Hampton Trust.

The CARA programme consists of two five-hour group discussions of between four and seven men, held on weekends one month apart, in which facilitators raise questions that cause attendees to reflect upon their behaviour and how they might change it.

Offenders in the other half, the control group, were given ‘conditional cautions’: meaning any repeat offence within four months would see prosecution in court. This is a commonly deployed police response to first arrests for low-harm domestic abuse.

Professor Strang and colleagues – including several Hampshire police leaders enrolled on the Cambridge Police Executive Programme – followed up with offenders a year after the first arrest. They found that 35% fewer men in the CARA group had committed any further offence against their partner.

However, Cambridge co-author Professor Lawrence Sherman describes such simplistic ‘crime counts’ as unhelpful when determining the real cost of crime: harm caused to victims. “The key result for the team came when we analysed all reoffending in both groups using the Cambridge Crime Harm Index,” he said.

This Harm Index, or CCHI, is a new tool that measures harm by weighting the severity of each crime in sentencing guidelines for different offences, rather than just totting up overall crime figures. The Office of National Statistics credits the CCHI as the stimulus for its own (modified) version of a harm index, introduced earlier this year.

Overall, those in the CARA group caused 27% less harm per offender to their partners than the control group.

Using the CCHI, the team calculated that the recommended number of prison days under English sentencing guidelines for reoffenders in the year following the first arrest was an average of 8.4 days for the CARA attendees, compared to an average of 11.6 days for offenders not sent to CARA.

“This would mean that, for every thousand first time offenders sent to CARA workshops, 380 days of recommended imprisonment would be saved, and victims would be spared the inflicted harm equivalent to 380 common assaults, or 19 assaults with actual bodily harm,” said Sherman.

Men who participated in the CARA workshops described having a greater understanding of the impact of their behaviour on partners and children, and when to walk away from a fight. Some talked of going on to attend support groups such as Alcoholics Anonymous as a result.

Chantal Hughes, Chief Executive of the Hampton Trust, said: “We know from consultations with victims that they want help for their partners. Those choosing not to remain in an intimate relationship often have children, and this means child contact arrangements. Victims have advised us that workshops such as CARA are a positive and much needed intervention.”

Study co-author Scott Chilton, Assistant Chief Constable of Hampshire Police and Chair of the Society of Evidence Based Policing, said: “CARA is an outstanding example of evidence based innovation that can influence national police policy and practices.

“This type of research, where professionals from law enforcement work with academia and charitable organisations, has proved to be extremely promising.”

A bizarre dinosaur which looked like a raptor but was in fact a vegetarian may be the missing link between plant-eating dinosaurs and theropods, the group that includes carnivores such as Tyrannosaurus rex and Velociraptor.

Researchers from the University of Cambridge and the Natural History Museum used a comprehensive dataset to analyse more than 450 anatomical characteristics of early dinosaurs and correctly place the creature, known as Chilesaurus, in the dinosaur family tree. Their results, reported in the journal Biology Letters, suggest that Chilesaurus effectively fills a large gap between two of the major dinosaur groups, and shows how the divide between them may have happened.

Chilesaurus, which was discovered in southern Chile, was first described in 2015. It lived during the Late Jurassic period, about 150 million years ago, and has an odd collection of physical characteristics, which made it difficult to classify. For example, its head resembles that of a carnivore, but it has flat teeth for grinding up plant matter.

“Chilesaurus almost looks like it was stitched together from different animals, which is why it baffled everybody,” said Matthew Baron, a PhD student in Cambridge’s Department of Earth Sciences and the paper’s joint first author.

Earlier research suggested that this peculiar dinosaur belonging to the group Theropoda, the ‘lizard-hipped’ group of dinosaurs that includes Tyrannosaurus, but the new study suggests that it was probably a very early member of a completely different group, called Ornithischia. This shuffling of the dinosaur family tree has major implications for understanding the origins of Ornithischia, the ‘bird-hipped’ group of dinosaurs that includes Stegosaurus, Triceratops and Iguanodon.

The bird-hipped dinosaurs have several common physical traits: the two most notable of these are an inverted, bird-like hip structure and a beak-like structure for eating. The inverted hips allowed for bigger, more complex digestive systems, which in turn allowed larger plant-eaters to evolve.

While Chilesaurus has a bird-like hip structure, and has flat teeth for grinding up plants, it does not possess the distinctive ‘beak’ of many other bird-hipped dinosaurs, which is what makes it such an important find.

“Before this, there were no transitional specimens – we didn’t know what order these characteristics evolved in,” said Baron. “This shows that in bird-hipped dinosaurs, the gut evolved first, and the jaws evolved later – it fills the gap quite nicely.”

“Chilesaurus is one of the most puzzling and intriguing dinosaurs ever discovered,” said co-author Professor Paul Barrett of the Natural History Museum. “Its weird mix of features places it in a key position in dinosaur evolution and helps to show how some of the really big splits between the major groups might have come about.”

“There was a split in the dinosaur family tree, and the two branches took different evolutionary directions,” said Baron. “This seems to have happened because of change in diet for Chilesaurus. It seems it became more advantageous for some of the meat eating dinosaurs to start eating plants, possibly even out of necessity.”

Earlier this year, the same group of researchers argued that dinosaur family groupings need to be rearranged, re-defined and re-named. In a study published in Nature, the researchers suggested that bird-hipped dinosaurs and lizard-hipped dinosaurs such as Tyrannosaurus evolved from a common ancestor, potentially overturning more than a century of theory about the evolutionary history of dinosaurs.

Although their dataset has already thrown up some surprising results, the researchers say that as it currently analyses only early dinosaurs, there are probably many more surprises about dinosaur evolution to be found, once characteristics of later dinosaurs are added.

The research was funded by the Natural Environment Research Council (NERC).

Reference:
Matthew G. Baron and Paul M. Barrett. ‘A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs.’ Biology Letters (2017). DOI: 10.1098/rsbl.2017.0220

Researchers have described a new species of brittle star, which are closely related to starfish, and showed how these sea creatures evolved in response to the rise of shell-crushing predators during the late Palaeozoic Era. The results, reported in the Journal of Systematic Palaeontology, also suggest that brittle stars evolved new traits before the largest mass extinction event in Earth’s history, and not after, as was the case with many other forms of life.

A fossilised ‘meadow’ of dancing brittle stars – frozen in time in the very spot that they lived – was found in Western Australia and dates from 275 million years ago. It contains several remarkably preserved ‘archaic’ brittle stars, a newly-described genus and species called Teleosaster creasyi. They are the last known complete brittle stars of their kind, an evolutionary hangover pushed to the margins of the world’s oceans by the threat from predators.

The researchers, from the University of Cambridge, suggest that while other species of brittle stars evolved in response to predators such as early forms of rays and crabs, these archaic forms simply moved to where the predators weren’t – namely the seas around Australia, which during the Palaeozoic era was pushed up against Antarctica. In these cold, predator-free waters, the archaic forms were able to grow much larger, and lived at the same time as the modern forms of brittle star, which still exist today.

Brittle stars consist of a central disc and five whip-like appendages, which are used for locomotion. They first appear in the fossil record about 500 million years ago, in the Ordovician Period, and today there are about 2,100 different species, mostly found in the deep ocean.

Early brittle stars were just that: brittle. During the Palaeozoic Era, when early shell-crushing predators first appeared, brittle stars made for easy prey. At this point, a split in the evolutionary tree appears to have occurred: the archaic, clunky brittle stars moved south to polar waters, while the modern form first began to emerge in response to the threat from predators, and was able to continue to live in the warmer waters closer to the equator. Both forms existed at the same time, but in different parts of the ocean.

“The threat from predation is an under-appreciated driver of evolutionary change,” said study co-author Dr Kenneth McNamara of Cambridge’s Department of Earth Sciences. “As more predators began to appear, the brittle stars started to evolve more flexible bodies, which enabled them to either burrow into the sediment, or to move more rapidly to escape.”

About 250 million years ago, the greatest mass extinction in Earth’s history – the Permian-Triassic extinction event, or the “Great Dying” – occurred. More than 90% of marine species and 70% of terrestrial species went extinct, and as a result, most surviving species underwent major evolutionary changes as a result.

“Brittle stars appear to have bucked this trend, however,” said co-author Dr Aaron Hunter, a visiting postdoctoral researcher in the Department of Earth Sciences. “They seem to have evolved before the Great Dying, into a form which we still see today.”

Meadows of brittle stars and other invertebrates such as sea urchins and starfish can still be seen today in the seas around Antarctica. As was the case during the Palaeozoic, the threat from predators is fairly low, although the warming of the Antarctic seas due to climate change has been linked to the recent arrival of armies of king crabs, which represent a real threat to these star-filled meadows.

Reference:
Aaron W. Hunter and Kenneth J. McNamara. ‘Prolonged co-existence of “Archaic” and “Modern” Palaeozoic ophiuroids – evidence from the early Permian, Southern Carnarvon Basin, Western Australia.’ Journal of Systematic Palaeontology (2017). DOI: 10.1080/14772019.2017.1353549

Inset image: Brittle stars, by Ratha Grimes.