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.

Norway is famed for its cod. Catches from the Arctic stock that spawn each year off its northern coast are exported across Europe for staple dishes from British fish and chips to Spanish bacalao stew.

Now, a new study published today in the journal PNAS suggests that some form of this pan-European trade in Norwegian cod may have been taking place for 1,000 years.

Latest research from the universities of Cambridge and Oslo, and the Centre for Baltic and Scandinavian Archaeology in Schleswig, used ancient DNA extracted from the remnants of Viking-age fish suppers.

The study analysed five cod bones dating from between 800 and 1066 AD found in the mud of the former wharves of Haithabu, an early medieval trading port on the Baltic. Haithabu is now a heritage site in modern Germany, but at the time was ruled by the King of the Danes.

The DNA from these cod bones contained genetic signatures seen in the Arctic stock that swim off the coast of Lofoten: the northern archipelago still a centre for Norway’s fishing industry.

Researchers say the findings show that supplies of ‘stockfish’ – an ancient dried cod dish popular to this day – were transported over a thousand miles from northern Norway to the Baltic Sea during the Viking era.

Prior to the latest study, there was no archaeological or historical proof of a European stockfish trade before the 12th century.

While future work will look at further fish remains, the small size of the current study prevents researchers from determining whether the cod was transported for trade or simply used as sustenance for the voyage from Norway.

However, they say that the Haithabu bones provide the earliest evidence of fish caught in northern Norway being consumed on mainland Europe – suggesting a European fish trade involving significant distances has been in operation for a millennium.

“Traded fish was one of the first commodities to begin to knit the European continent together economically,” says Dr James Barrett, senior author of the study from the University of Cambridge’s McDonald Institute for Archaeological Research.

“Haithabu was an important trading centre during the early medieval period. A place where north met south, pagan met Christian, and those who used coin met those who used silver by weight.”

“By extracting and sequencing DNA from the leftover fish bones of ancient cargoes at Haithabu, we have been able to trace the source of their food right the way back to the cod populations that inhabit the Barents Sea, but come to spawn off Norway’s Lofoten coast every winter.

“This Arctic stock of cod is still highly prized – caught and exported across Europe today. Our findings suggest that distant requirements for this Arctic protein had already begun to influence the economy and ecology of Europe in the Viking age.”

Stockfish is white fish preserved by the unique climate of north Norway, where winter temperature hovers around freezing. Cod is traditionally hung out on wooden frames to allow the chill air to dry the fish. Some medieval accounts suggest stockfish was still edible as much as ten years after preservation.

The research team argue that the new findings offer some corroboration to the unique 9th century account of the voyages of Ohthere of Hålogaland: a Viking chieftain whose visit to the court of King Alfred in England resulted in some of his exploits being recorded.

“In the accounts inserted by Alfred’s scribes into the translation of an earlier 5th century text, Ohthere describes sailing from Hålogaland to Haithabu,” says Barrett. Hålogaland was the northernmost province of Norway. 

“While no cargo of dried fish is mentioned, this may be because it was simply too mundane a detail,” says Barrett. “The fish-bone DNA evidence is consistent with the Ohthere text, showing that such voyages between northern Norway and mainland Europe were occurring.”

“The Viking world was complex and interconnected. This is a world where a chieftain from north Norway may have shared stockfish with Alfred the Great while a late-antique Latin text was being translated in the background. A world where the town dwellers of a cosmopolitan port in a Baltic fjord may have been provisioned from an Arctic sea hundreds of miles away.”

The sequencing of the ancient cod genomes was done at the University of Oslo, where researchers are studying the genetic makeup of Atlantic cod in an effort to unpick the anthropogenic impacts on these long-exploited fish populations.

“Fishing, particularly of cod, has been of central importance for the settlement of Norway for thousands of years. By combining fishing in winter with farming in summer, whole areas of northern Norway could be settled in a more reliable manner,” says the University of Oslo’s Bastiaan Star, first author of the new study.

Star points to the design of Norway’s new banknotes that prominently feature an image of cod, along with a Viking ship, as an example of the cultural importance still placed on the fish species in this part of Europe.

“We want to know what impact the intensive exploitation history covering millennia has inflicted on Atlantic cod, and we use ancient DNA methods to investigate this,” he says.

The study was funded by the Research Council of Norway and the Leverhulme Trust.

The researchers, from the University of Cambridge, used data from Twitter to determine whether bots can be accurately detected, how bots behave, and how they impact Twitter activity.

They divided accounts into categories based on total number of followers, and found that accounts with more than 10 million followers tend to retweet at similar rates to bots. In accounts with fewer followers however, bots tend to retweet far more than humans. These celebrity-level accounts also tweet at roughly the same pace as bots with similar follower numbers, whereas in smaller accounts, bots tweet far more than humans. Their results will be presented at the IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM) in Sydney, Australia.

Bots, like people, can be malicious or benign. The term ‘bot’ is often associated with spam, offensive content or political infiltration, but many of the most reputable organisations in the world also rely on bots for their social media channels. For example, major news organisations, such as CNN or the BBC, who produce hundreds of pieces of content daily, rely on automation to share the news in the most efficient way. These accounts, while classified as bots, are seen by users as trustworthy sources of information.

“A Twitter user can be a human and still be a spammer, and an account can be operated by a bot and still be benign,” said Zafar Galani, a PhD student at Cambridge’s Computer Laboratory, who led the research. “We’re interested in seeing how effectively we can detect automated accounts and what effects they have.”

Bots have been on Twitter for the majority of the social network’s existence – it’s been estimated that anywhere between 40 and 60% of all Twitter accounts are bots. Some bots have tens of millions of followers, although the vast majority have less than a thousand – human accounts have a similar distribution.

In order to reliably detect bots, the researchers first used the online tool BotOrNot (since renamed BotOMeter), which is one of the only available online bot detection tools. However, their initial results showed high levels of inaccuracy. BotOrNot showed low precision in detecting bots that had bot-like characteristics in their account name, profile info, content tweeting frequency and especially redirection to external sources. Gilani and his colleagues then decided to take a manual approach to bot detection.

Four undergraduate students were recruited to manually inspect accounts and determine whether they were bots. This was done using a tool that automatically presented Twitter profiles, and allowed the students to classify the profile and make notes. Each account was collectively reviewed before a final decision was reached.

In order to determine whether an account was a bot (or not), the students looked at different characteristics of each account. These included the account creation date, average tweet frequency, content posted, account description, whether the user replies to tweets, likes or favourites received and the follower to friend ratio. A total of 3,535 accounts were analysed: 1,525 were classified as bots and 2010 as humans.

The students showed very high levels of agreement on whether individual accounts were bots. However, they showed significantly lower levels of agreement with the BotOrNot tool.

The bot detection algorithm they subsequently developed achieved roughly 86% accuracy in detecting bots on Twitter. The algorithm uses a type of classifier known as Random Forests, which uses 21 different features to detect bots, and the classifier itself is trained by the original dataset annotated by the human annotators.

The researchers found that bot accounts differ from humans in several key ways. Overall, bot accounts generate more tweets than human accounts. They also retweet far more often, and redirect users to external websites far more frequently than human users. The only exception to this was in accounts with more than 10 million followers, where bots and humans showed far more similarity in terms of the volume of tweets and retweets.

“We think this is probably because bots aren’t that good at creating original Twitter content, so they rely a lot more on retweets and redirecting followers to external websites,” said Galani. “While bots are getting more sophisticated all the time, they’re still pretty bad at one-on-one Twitter conversations, for instance – most of the time, a conversation with a bot will be mostly gibberish.”

Despite the sheer volume of Tweets produced by bots, humans still have better quality and more engaging tweets – tweets by human accounts receive on average 19 times more likes and 10 times more retweets than tweets by bot accounts. Bots also spend less time liking other users’ tweets.

“Many people tend to think that bots are nefarious or evil, but that’s not true,” said Galani. “They can be anything, just like a person. Some of them aren’t exactly legal or moral, but many of them are completely harmless. What I’m doing next is modelling the social cost of these bots – how are they changing the nature and quality of conversations online? What is clear though, is that bots are here to stay.”

Reference: 
Zafar Galani, Ekaterina Kochmar, Jon Crowcroft. Classification of Twitter Accounts into Automated Agents and Human Users. Paper presented at 9th IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM’17). Sydney, New South Wales, Australia.

Scientist have sequenced the entire genomes of 4,000-year-old Canaanite individuals who inhabited the Near East region during the Bronze Age, and compared these to other ancient and present-day populations. The results, published in the American Journal of Human Genetics, suggest that present-day Lebanese are direct descendants of the ancient Canaanites.

The Near East is often described as the cradle of civilisation. The Bronze Age Canaanites, later known as the Phoenicians, introduced many aspects of society that we know today – they created the first alphabet, established colonies throughout the Mediterranean and were mentioned several times in the Bible.

However, historical records of the Canaanites are limited. They were mentioned in ancient Greek and Egyptian texts, and the Bible which reports widespread destruction of Canaanite settlements and annihilation of the communities. Experts have long debated who the Canaanites were genetically, what happened to them, who their ancestors were and if they had any descendants today.

In the first study of its kind, an international team of scientists have uncovered the genetics of the Canaanite people and a firm link with people living in Lebanon today. The team discovered that more than 90 per cent of present-day Lebanese ancestry is likely to be from the Canaanites, with an additional small proportion of ancestry coming from a different Eurasian population.

The team, including researchers from Cambridge University’s Department of Archaeology and Anthropology, and led by the Wellcome Trust Sanger Institute, estimate that new Eurasian people mixed with the Canaanite population about 2,200 to 3,800 years ago at a time when there were many conquests of the region from outside.

The analysis of ancient DNA also revealed that the Canaanites themselves were a mixture of local people who settled in farming villages during the Neolithic period and eastern migrants who arrived in the area around 5,000 years ago.

“Ancient DNA is becoming an indispensable tool for understanding population movements of the past. This study in particular provides previously inaccessible information about a group of people known only by surviving written accounts and interpretations of archaeological findings,” said Dr. C L Scheib, one of two Cambridge co-authors, along with Dr Toomas Kivisild.

“The fact that we can retrieve whole genomes from conditions not considered ideal for DNA preservation also shows how far the field has advanced technically,” she said.

In the study, researchers sequenced whole genomes of five Canaanite individuals who lived 4,000 years ago in a city known as Sidon in present-day Lebanon. Scientists also sequenced the genomes of 99 present-day Lebanese and analysed the genetic relationship between the ancient Canaanites and modern Lebanese.

Dr Marc Haber, first author from the Sanger Institute, said: “It was a pleasant surprise to be able to extract and analyse DNA from 4,000-year-old human remains found in a hot environment, which is not known for preserving DNA well. We overcame this challenge by taking samples from the petrous bone in the skull, which is a very tough bone with a high density of ancient DNA.”

Dr Claude Doumet-Serhal, co-author and Director of the Sidon excavation site in Lebanon, said: “For the first time we have genetic evidence for substantial continuity in the region, from the Bronze Age Canaanite population through to the present day. These results agree with the continuity seen by archaeologists.

“Collaborations between archaeologists and geneticists greatly enrich both fields of study and can answer questions about ancestry in ways that experts in neither field can answer alone.”

Adapted from a Wellcome Trust press release. 

Our lives benefit from social networks: the contact and dialogue between family, friends, colleagues and neighbours. However these networks can also cost lives by transmitting infection or misinformation, particularly in developing nations.

In fact, when there is an outbreak of disease, or of damaging rumour that hinders uptake of vaccination, the network through which it spreads needs to be broken up – and fast.

But who are the people with most connections – the ‘hubs’ in any social network – that should be targeted with inoculating drugs or health education in order to quickly isolate a contagion?

Information about social networks in rural villages in the developing world is costly and time-consuming to collect, and usually unavailable. So current immunisation strategies target people with established community roles: healthcare workers, teachers, and local officials.

Now, Cambridge researchers have for the first time combined networking theories with ‘real world’ data collected from thousands of rural Ugandan households, and shown that a simple algorithm may be significantly more effective at finding the highly connected ‘hubs’ to target for halting disease spread.

The ‘acquaintance algorithm’ employed by researchers is remarkably simple: select village households at random and ask who in their network is most trusted for medical advice.

Researchers were surprised to find that the most influential people in social networks were very often not those with obvious positions in a community. As such, these valuable ‘hubs’ are invisible to drug administration programmes without the algorithmic approach.

“Everyone is a node in a social network. Most nodes have just a few connections. However, a small number of nodes have the majority of connections. These are the hubs we want to uncover and target in order to intentionally cause failure in social networks spreading pathogens or damaging behaviour,” says lead researcher Dr Goylette Chami, from Cambridge’s Department of Pathology.

“It was striking to find that important village positions may be best left untargeted for interventions seeking to stop the spread of pathogens through a rural social network,” says Chami.

In the study, published today in the journal PNAS, the researchers write that this simple strategy could be particularly effective for isolating households that refuse to take medicine, so that they don’t endanger the rest of a community with infection.

To control disease caused by parasitic worm infections, for example, at least three quarters of any given community need to be treated. “The refusal of treatment by a few people can result in the destabilisation of mass drug administration programmes that aim to treat 1.9 billion people worldwide,” says Chami.

An average of just 32% of households (‘nodes’) selected by the acquaintance algorithm need to be provided health education (and ‘removed’ from a network) to reach the disease control threshold for an entire community. Using traditional role-based targeting, the average needed is much larger: some 54%.

“We discovered that acquaintance algorithms outperformed the conventional field-based approaches of targeting well-established community roles for finding individuals with the most connections to sick people, as well as isolating the spread of misinformation,” says Chami

“Importantly, this simple strategy doesn’t require any information on who holds which role and how to reach them. No database is needed. As such, it is easy to deploy in rural, low-income settings.”

“In an ideal world, everyone would be treated,” says Chami. “However, with limited resources, time and information, finding the best connected neighbours, the ‘hubs’, and removing them through treatment, looks to be the quickest way to fragment a network that spreads infections, and to render the most people safe.”

Chami and colleagues from Cambridge and the Ugandan Ministry of Health collected data on social and health advice networks from over 16,000 people in 17 villages across rural Uganda. They also collected data on networks of disease using reports of diarrhoea as a proxy for infection spread – particularly relevant to recent large-scale cholera outbreaks.

To do this, Chami built a survey app from open source code and loaded it on to 76 Google nexus tablets. The team then trained a number of individuals from the local villages to help them go door to door.

Adds Chami: “This kind of ‘network theory’ approach to public health in the developing world, and the use of acquaintance algorithms, if tested in randomised controlled trials, may increase compliance to treatments and inform strategies for the distribution of vaccines.”

The two collaborations are focused on food security in India and public health in Bangladesh and will see researchers from the UK and developing countries working together as equal partners.

The awards are part of the Global Challenges Research Fund, which aims to build upon research knowledge in the UK, and strengthen capacity overseas, to help address challenges, informed by expressed need in the developing countries.

Jo Johnson, Minister for Universities and Science, said: “From healthcare to green energy, the successful projects receiving funding today highlight the strength of the UK’s research base and our leadership in helping developing countries tackle some of the greatest global issues of our time.

“At a time when the pace of scientific discovery and innovation is quickening, we are placing science and research at the heart of our Industrial Strategy to build on our strengths and maintain our status as science powerhouse.”

Andrew Thompson, GCRF Champion at Research Councils UK, said: “The 37 projects announced today build research capacity both here in the UK and in developing countries to address systemic development challenges,  from African agriculture to sustainable cities, clean oceans, and green energy, to improved healthcare, food security, and gender equality.”

TIGR²ESS (Transforming India’s Green Revolution by Research and Empowerment for Sustainable food Supplies)

Lead: Professor Howard Griffiths (Department of Plant Sciences)

Talk of a second Green Revolution has been around for a while. The first – in India and other developing countries, in the 1960s – brought a massive increase in crop production that sustained the country’s mushrooming population. But now there are new pressures – not just the need to produce even more food, but to reduce the damage done by excessive use of pesticides, fertiliser and water in the face of climate change.

TIGR²ESS, a collaboration between UK and Indian scientists, seeks to frame the big question – how to bring about a second Green revolution – in all its breadth and depth. India is developing fast– agriculture needs to take account of urbanisation, for example, which has drawn so many away from the land. Smallholder farmers- particularly women- need smart technologies to sustain crop yields, and improve health and nutrition.

The TIGR²ESS programme will assess these options, as well as supporting basic research programmes, and providing advice to local communities. There will be many opportunities for academic exchanges, mentoring and career development for scientists from both countries. Links with the relevant government ministries in India, plus industrial connections built into the programme, will hopefully turn the best recommendations into reality.

“We are extremely pleased that the TIGR²ESS programme will help to deliver our vision for partnerships with institutions in India to improve crop science and food security,” says Professor Howard Griffiths, Co-Chair of the University of Cambridge’s Strategic Initiative in Global Food Security.

“Agriculture is feminizing. We need to ensure that state resources and services, and knowledge resources, are equally accessible to women farmers,” adds Dr V Selvam, MS Swaminathan Research Foundation, India, one of the collaborators.

CAPABLE (Cambridge Programme to Assist Bangladesh in Lifestyle and Environmental risk reduction)

Lead: Professor John Danesh (Department of Public Health and Primary Care)

Gathering a big group of people and studying their health in the long term can uncover game-changing facts. The British Doctors’ Study, for example, which began in 1951, revealed that smoking causes lung cancer. Imagine if the same could be done in a country facing a perfect storm of chronic health problems.

Bangladesh is admired worldwide for its success in cutting child mortality and fertility rate, yet it faces an onslaught of chronic diseases that arise from an interplay of factors ranging from arsenic-contaminated drinking water to iron-deficient foods and from air pollution to the rise of the western lifestyle.

CAPABLE has the ambitious goal of recruiting 100,000 people from landscapes ranging from the green paddy fields of rural Bangladesh to the slums of the densest city in the world – Dhaka. From their data, engineers, sociologists, health researchers and a host of other disciplines will try to understand how the risk factors interact – and build a model that can be used to test interventions before they are implemented.

“We aim to help develop simple, scalable and effective solutions to control major environmental and lifestyle risk factors in Bangladesh,” says Scientific Director of the CAPABLE programme Dr Rajiv Chowdhury from the Department of Public Health and Primary Care at the University of Cambridge.

Individuals who have had a stroke are at risk of a second stroke, which carries a greater risk of disability and death than first time strokes. In fact, one third of all strokes occur in individuals who have previously had a stroke. To prevent this recurrence, patients are offered secondary preventative medications; however, adherence is a problem with 30% of stroke patients failing to take their medications as prescribed.

To examine the barriers to taking these medications, researchers at the University of Cambridge and Queen Mary University, London (QMUL), analysed posts to TalkStroke, a UK-based online forum hosted by the Stroke Association, across a seven year period (2004-2011).  The forum was used by stroke survivors and their carers.

The team, led by Dr Anna De Simoni, a lecturer in Primary Care Research at QMUL and visiting researcher at the Department of Public Health and Primary Care, University of Cambridge, has previously used the forum to explore issues such as the impairment that can make it difficult for stroke survivors to maintain a job.

The findings of the study, which looked at posts by 84 participants, including 49 stroke survivors and 33 caregivers, are published today in the journal BMJ Open. The Stroke Association gave the researchers permission to analyse the results, and to prevent identification of individuals, the team did not use verbatim comments.

Among the reasons cited by the forum users, side effects were a major factor in decisions to stop taking medication. Several contributors had experienced negative side effects and as a result had stopped taking the medication, sometimes in consultation with their GP and other times unilaterally. Others reported that they, or the person they were caring for, had stopped taking the medication after reading negative stories in the press about side effects.

Other users expressed concerns over the medication they were offered. There were conflicting views about the efficacy of the medications – some contributors believed they were very important, while others believed that their risk could be managed by lifestyle changes alone.

Contributors also reported mixed views of healthcare professionals – some felt confident in their doctor’s decision, while others questioned their decisions, some even questioning their motivation for prescribing particular drugs.

“These findings have highlighted the need for an open, honest dialogue between patients and/or their carers, and healthcare professionals,” says Dr De Simoni. “Doctors need to listen to these concerns, discuss the benefits and drawbacks of taking the medication, and be willing to support a patient’s informed decision to refuse medications.”

However, perceptions did not present the only barriers to adherence: there were often practical considerations. Drugs were sometimes too large and difficult to swallow, or a drug regime was too burdensome. The complexities of the drug regimens sometimes meant having to develop routines and strategies to ensure patients kept to them. One survivor described having to pay for the medications by credit card as she was unable to work and had no money or benefits coming in.

“By analysing people’s views as expressed in online forums, where they are more open and less guarded, we’ve seen some valuable insights into why some stroke survivors have difficulty adhering to their medication,” says PhD candidate and first author James Jamison from the Department of Public Health and Primary Care at Cambridge.

“Challenging negative beliefs about medication and adopting practices that make routines for taking medication simpler, particularly for those patients who have suffered disability as a result of stroke, should increase adherence and ultimately improve health outcomes.”

The research was supported by the National Institute of Health Research, the Stroke Association and the British Heart Foundation.

For more information about statins, visit NHS Choices.

Reference
Jamison, J et al. Barriers and facilitators to adherence to secondary stroke prevention medications after stroke: Analysis of survivors’ and caregivers’ views from an online stroke forum. BMJ Open; 19 July 2017; DOI: 10.17863/CAM.10458

The smallest star yet measured has been discovered by a team of astronomers led by the University of Cambridge. With a size just a sliver larger than that of Saturn, the gravitational pull at its stellar surface is about 300 times stronger than what humans feel on Earth.

The star is likely as small as stars can possibly become, as it has just enough mass to enable the fusion of hydrogen nuclei into helium. If it were any smaller, the pressure at the centre of the star would no longer be sufficient to enable this process to take place. Hydrogen fusion is also what powers the Sun, and scientists are attempting to replicate it as a powerful energy source here on Earth.

These very small and dim stars are also the best possible candidates for detecting Earth-sized planets which can have liquid water on their surfaces, such as TRAPPIST-1, an ultracool dwarf surrounded by seven temperate Earth-sized worlds.

The newly-measured star, called EBLM J0555-57Ab, is located about six hundred light years away. It is part of a binary system, and was identified as it passed in front of its much larger companion, a method which is usually used to detect planets, not stars. Details will be published in the journal Astronomy & Astrophysics.

“Our discovery reveals how small stars can be,” said Alexander Boetticher, the lead author of the study, and a Master’s student at Cambridge’s Cavendish Laboratory and Institute of Astronomy. “Had this star formed with only a slightly lower mass, the fusion reaction of hydrogen in its core could not be sustained, and the star would instead have transformed into a brown dwarf.”

EBLM J0555-57Ab was identified by WASP, a planet-finding experiment run by the Universities of Keele, Warwick, Leicester and St Andrews. EBLM J0555-57Ab was detected when it passed in front of, or transited, its larger parent star, forming what is called an eclipsing stellar binary system. The parent star became dimmer in a periodic fashion, the signature of an orbiting object. Thanks to this special configuration, researchers can accurately measure the mass and size of any orbiting companions, in this case a small star. The mass of EBLM J0555-57Ab was established via the Doppler, wobble method, using data from the CORALIE spectrograph.

“This star is smaller, and likely colder than many of the gas giant exoplanets that have so far been identified,” said von Boetticher. “While a fascinating feature of stellar physics, it is often harder to measure the size of such dim low-mass stars than for many of the larger planets. Thankfully, we can find these small stars with planet-hunting equipment, when they orbit a larger host star in a binary system. It might sound incredible, but finding a star can at times be harder than finding a planet.”

This newly-measured star has a mass comparable to the current estimate for TRAPPIST-1, but has a radius that is nearly 30% smaller. “The smallest stars provide optimal conditions for the discovery of Earth-like planets, and for the remote exploration of their atmospheres,” said co-author Amaury Triaud, senior researcher at Cambridge’s Institute of Astronomy. “However, before we can study planets, we absolutely need to understand their star; this is fundamental.”

Although they are the most numerous stars in the Universe, stars with sizes and masses less than 20% that of the Sun are poorly understood, since they are difficult to detect due to their small size and low brightness. The EBLM project, which identified the star in this study, aims to plug that lapse in knowledge. “Thanks to the EBLM project, we will achieve a far greater understanding of the planets orbiting the most common stars that exist, planets like those orbiting TRAPPIST-1,” said co-author Professor Didier Queloz of Cambridge’ Cavendish Laboratory.

Reference
Alexander von Boetticher et al. ‘A Saturn-size low-mass star at the hydrogen-burning limit.’ Astronomy & Astrophysics (2017). arXiv:1706.08781

A team of architects and chemists from the University of Cambridge has designed super-stretchy and strong fibres which are almost entirely composed of water, and could be used to make textiles, sensors and other materials. The fibres, which resemble miniature bungee cords as they can absorb large amounts of energy, are sustainable, non-toxic and can be made at room temperature.

This new method not only improves upon earlier methods of making synthetic spider silk, since it does not require high energy procedures or extensive use of harmful solvents, but it could substantially improve methods of making synthetic fibres of all kinds, since other types of synthetic fibres also rely on high-energy, toxic methods. The results are reported in the journal Proceedings of the National Academy of Sciences.

Spider silk is one of nature’s strongest materials, and scientists have been attempting to mimic its properties for a range of applications, with varying degrees of success. “We have yet to fully recreate the elegance with which spiders spin silk,” said co-author Dr Darshil Shah from Cambridge’s Department of Architecture.

The fibres designed by the Cambridge team are “spun” from a soupy material called a hydrogel, which is 98% water. The remaining 2% of the hydrogel is made of silica and cellulose, both naturally available materials, held together in a network by barrel-shaped molecular “handcuffs” known as cucurbiturils. The chemical interactions between the different components enable long fibres to be pulled from the gel.

The fibres are pulled from the hydrogel, forming long, extremely thin threads – a few millionths of a metre in diameter. After roughly 30 seconds, the water evaporates, leaving a fibre which is both strong and stretchy.

“Although our fibres are not as strong as the strongest spider silks, they can support stresses in the range of 100 to 150 megapascals, which is similar to other synthetic and natural silks,” said Shah. “However, our fibres are non-toxic and far less energy-intensive to make.”

The fibres are capable of self-assembly at room temperature, and are held together by supramolecular host-guest chemistry, which relies on forces other than covalent bonds, where atoms share electrons.

“When you look at these fibres, you can see a range of different forces holding them together at different scales,” said Yuchao Wu, a PhD student in Cambridge’s Department of Chemistry, and the paper’s lead author. “It’s like a hierarchy that results in a complex combination of properties.”

The strength of the fibres exceeds that of other synthetic fibres, such as cellulose-based viscose and artificial silks, as well as natural fibres such as human or animal hair.

In addition to its strength, the fibres also show very high damping capacity, meaning that they can absorb large amounts of energy, similar to a bungee cord. There are very few synthetic fibres which have this capacity, but high damping is one of the special characteristics of spider silk. The researchers found that the damping capacity in some cases even exceeded that of natural silks.

“We think that this method of making fibres could be a sustainable alternative to current manufacturing methods,” said Shah. The researchers plan to explore the chemistry of the fibres further, including making yarns and braided fibres.

This research is the result of a collaboration between the Melville Laboratory for Polymer Synthesis in the Department of Chemistry, led by Professor Oren Scherman; and the Centre for Natural Material Innovation in the Department of Architecture, led by Dr Michael Ramage. The two groups have a mutual interest in natural and nature-inspired materials, processes and their applications across different scales and disciplines.

The research is supported by the UK Engineering and Physical Sciences Research Council (EPSRC) and the Leverhulme Trust.

Reference
Yuchao Wu et al. ‘Bioinspired supramolecular fibers drawn from a multiphase self-assembled hydrogel.’ Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1705380114

In research published in the journal Nature Medicine, the researchers grew 3D cellular structure which, once transplanted into mice, developed into normal, functioning bile ducts.

Bile ducts are long, tube-like structures that carry bile, which is secreted by the liver and is essential for helping us digest food. If the ducts do not work correctly, for example in the childhood disease biliary atresia, this can lead to damaging build of bile in the liver.

The study suggests that it will be feasible to generate and transplant artificial human bile ducts using a combination of cell transplantation and tissue engineering technology. This approach provides hope for the future treatment of diseases of the bile duct; at present, the only option is a liver transplant.

The University of Cambridge research team, led by Professor Ludovic Vallier and Dr Fotios Sampaziotis from the Wellcome-MRC Cambridge Stem Cell Institute and Dr Kourosh Saeb-Parsy from the Department of Surgery, extracted healthy cells (cholangiocytes) from bile ducts and grew these into functioning 3D duct structures known as biliary organoids.  When transplanted into mice, the biliary organoids assembled into intricate tubular structures, resembling bile ducts.

The researchers, in collaboration with Mr Alex Justin and Dr Athina Markaki from the Department of Engineering, then investigated whether the biliary organoids could be grown on a ‘biodegradable collagen scaffold’, which could be shaped into a tube and used to repair damaged bile ducts in the body.  After four weeks, the cells had fully covered the miniature scaffolding resulting in artificial tubes which exhibited key features of a normal, functioning bile duct.  These artificial ducts were then used to replace damaged bile ducts in mice.  The artificial duct transplants were successful, with the animals surviving without further complications.

“Our work has the potential to transform the treatment of bile duct disorders,” explains Professor Vallier. “At the moment, our only option is liver transplantation, so we are limited by the availability of healthy organs for transplantation. In future, we believe it will be possible to generate large quantities of bioengineered tissue that could replace diseased bile ducts and provide a powerful new therapeutic option without this reliance on organ transplants.”

“This demonstrates the power of tissue engineering and regenerative medicine,” adds Dr Sampaziotis. “These artificial bile ducts will not only be useful for transplanting, but could also be used to model other diseases of the bile duct and potentially develop and test new drug treatments.”

Professor Vallier is part of the Department of Surgery at the University of Cambridge and his team are jointly based at the Wellcome Trust-MRC Cambridge Stem Cell Institute and the Wellcome Trust Sanger Institute.

The work was supported by the Medical Research Council, Sparks children’s medical research charity and the European Research Council.

Reference
Sampaziotis, F et al. Reconstruction of the murine extrahepatic biliary tree using primary extrahepatic cholangiocyte organoids. Nature Medicine; 3 July 2017; DOI: 10.1038/nm.4360

Amnestic mild cognitive impairment (aMCI) has been described as the transitional stage between ‘healthy ageing’ and dementia. It is characterised by day-to-day memory difficulties and problems of motivation. At present, there are no approved drug treatments for the cognitive impairments of patients affected by the condition.

Cognitive training has shown some benefits, such as speed of attentional processing, for patients with aMCI, but training packages are typically repetitive and boring, affecting patients’ motivation. To overcome this problem, researchers from the Departments of Psychiatry and Clinical Neurosciences and the Behavioural and Clinical Neuroscience Institute at the University of Cambridge developed ‘Game Show’, a memory game app, in collaboration with patients with aMCI, and tested its effects on cognition and motivation.

The researchers randomly assigned forty-two patients with amnestic MCI to either the cognitive training or control group. Participants in the cognitive training group played the memory game for a total of eight one-hour sessions over a four-week period; participants in the control group continued their clinic visits as usual.

In the game, which participants played on an iPad, the player takes part in a game show to win gold coins. In each round, they are challenged to associate different geometric patterns with different locations. Each correct answer allows the player to earn more coins. Rounds continue until completion or after six incorrect attempts are made. The better the player gets, the higher the number of geometric patterns presented – this helps tailor the difficulty of the game to the individual’s performance to keep them motivated and engaged. A game show host encourages the player to maintain and progress beyond their last played level.

Screenshot from Game Show. Credit: Sahakian Lab

The results showed that patients who played the game made around a third fewer errors, needed fewer trials and improved their memory score by around 40%, showing that they had correctly remembered the locations of more information at the first attempt on a test of episodic memory. Episodic memory is important for day-to-day activities and is used, for example, when remembering where we left our keys in the house or where we parked our car in a multi-story car park. Compared to the control group, the cognitive training group also retained more complex visual information after training.

In addition, participants in the cognitive training group indicated that they enjoyed playing the game and were motivated to continue playing across the eight hours of cognitive training. Their confidence and subjective memory also increased with gameplay. The researchers say that this demonstrates that games can help maximise engagement with cognitive training.

“Good brain health is as important as good physical health. There’s increasing evidence that brain training can be beneficial for boosting cognition and brain health, but it needs to be based on sound research and developed with patients,” says Professor Barbara Sahakian, co-inventor of the game: “It also need to be enjoyable enough to motivate users to keep to their programmes. Our game allowed us to individualise a patient’s cognitive training programme and make it fun and enjoyable for them to use.”

Dr George Savulich, the lead scientist on the study, adds: “Patients found the game interesting and engaging and felt motivated to keep training throughout the eight hours. We hope to extend these findings in future studies of healthy ageing and mild Alzheimer’s disease.”

The researchers hope to follow this published study up with a future large-scale study and to determine how long the cognitive improvements persist.

The design of ‘Game Show’ was based on published research from the Sahakian Laboratory at the University of Cambridge. The study was funded by Janssen Pharmaceuticals/J&J and Wellcome.

In 2015, Professor Sahakian and colleagues showed that another iPad game developed by her team was effective at improving the memory of patients with schizophrenia, helping them in their daily lives at work and living independently. The Wizard memory game is available through PEAK via the App Store and Google Play.

Reference
George Savulich, Thomas Piercy, Chris Fox, John Suckling, James Rowe, John O’Brien, Barbara Sahakian. Cognitive training using a novel memory game on an iPad in patients with amnestic mild cognitive impairment (aMCI). The International Journal of Neuropsychopharmacology; 3 July 2017; DOI: 10.1093/ijnp/pyx040

Using a technique called ‘seismic noise interferometry’ combined with geophysical measurements, the researchers measured the energy moving through a volcano. They found that there is a good correlation between the speed at which the energy travelled and the amount of bulging and shrinking observed in the rock. The technique could be used to predict more accurately when a volcano will erupt. Their results are reported in the journal Science Advances.

Data was collected by the US Geological Survey across Kīlauea in Hawaii, a very active volcano with a lake of bubbling lava just beneath its summit. During a four-year period, the researchers used sensors to measure relative changes in the velocity of seismic waves moving through the volcano over time. They then compared their results with a second set of data which measured tiny changes in the angle of the volcano over the same time period.

As Kīlauea is such an active volcano, it is constantly bulging and shrinking as pressure in the magma chamber beneath the summit increases and decreases. Kīlauea’s current eruption started in 1983, and it spews and sputters lava almost constantly. Earlier this year, a large part of the volcano fell away and it opened up a huge ‘waterfall’ of lava into the ocean below. Due to this high volume of activity, Kīlauea is also one of the most-studied volcanoes on Earth.

The Cambridge researchers used seismic noise to detect what was controlling Kīlauea’s movement. Seismic noise is a persistent low-level vibration in the Earth, caused by everything from earthquakes to waves in the ocean, and can often be read on a single sensor as random noise. But by pairing sensors together, the researchers were able to observe energy passing between the two, therefore allowing them to isolate the seismic noise that was coming from the volcano.

“We were interested in how the energy travelling between the sensors changes, whether it’s getting faster or slower,” said Clare Donaldson, a PhD student in Cambridge’s Department of Earth Sciences, and the paper’s first author. “We want to know whether the seismic velocity changes reflect increasing pressure in the volcano, as volcanoes bulge out before an eruption. This is crucial for eruption forecasting.”

One to two kilometres below Kīlauea’s lava lake, there is a reservoir of magma. As the amount of magma changes in this underground reservoir, the whole summit of the volcano bulges and shrinks. At the same time, the seismic velocity changes. As the magma chamber fills up, it causes an increase in pressure, which leads to cracks closing in the surrounding rock and producing faster seismic waves – and vice versa.

“This is the first time that we’ve been able to compare seismic noise with deformation over such a long period, and the strong correlation between the two shows that this could be a new way of predicting volcanic eruptions,” said Donaldson.

Volcano seismology has traditionally measured small earthquakes at volcanoes. When magma moves underground, it often sets off tiny earthquakes, as it cracks its way through solid rock. Detecting these earthquakes is therefore very useful for eruption prediction. But sometimes magma can flow silently, through pre-existing pathways, and no earthquakes may occur. This new technique will still detect the changes caused by the magma flow.

Seismic noise occurs continuously, and is sensitive to changes that would otherwise have been missed. The researchers anticipate that this new research will allow the method to be used at the hundreds of active volcanoes around the world.

Reference
C. Donaldson et al. ‘Relative seismic velocity variations correlate with deformation at Kīlauea volcano’. Science Advances (2017) DOI: 10.1126/sciadv.1700219 

Inset image: Lava Waterfall, Kilauea Volcano, Hawaii. Credit: Dhilung Kirat

At the moment they come together, the individual grains in materials like sand and snow appear to have exactly the same probability of combining into any one of their many billions of possible arrangements, researchers have shown.

The finding, by an international team of academics at the University of Cambridge, UK, and Brandeis University in the US, appears to confirm a decades-old mathematical theory which has never been proven, but provides the basis for better understanding granular materials – one of the most industrially significant classes of material on the planet.

A granular material is anything that comprises solid particles that can be seen individually with the naked eye. Examples include sand, gravel, snow, coal, coffee, and rice.

If correct, the theory demonstrated in the new study points to a fact of remarkable – and rather mysterious – mathematical symmetry. It means, for example, that every single possible arrangement of the grains of sand within a sand dune is exactly as probable as any other.

The study was led by Stefano Martiniani, who is based at New York University but undertook the research while completing his PhD at St John’s College, University of Cambridge.

“Granular materials are so widely-used that understanding their physics is very important,” Martiniani said. “This theory gives us a very simple and elegant way to describe their behaviour. Clearly, something very special is happening in their physics at the moment when grains pack together in this way.”

The conjecture that Martiniani tested was first proposed in 1989 by the Cambridge physicist Sir Sam F. Edwards, in an effort to better understand the physical properties of granular materials.

Globally, these are the second-most processed type of material in industry (after water) and staples of sectors such as energy, food and pharmaceuticals. In the natural world, vast granular assemblies, such as sand dunes, interact directly with wind, water and vegetation. Yet the physical laws that determine how they behave in different conditions are still poorly understood. Sand, for example, behaves like a solid when jammed together, but flows like a liquid when loose.

Understanding more about the mechanics of granular materials is of huge practical importance. When they jam during industrial processing, for example, it can cause significant disruption and damage. Equally, the potential for granular materials to “unjam” can be disastrous, such as when soil or snow suddenly loosens, causing a landslide or avalanche.

At the heart of Edwards’ proposal was a simple hypothesis: If one does not explicitly add a bias when preparing a jammed packing of granular materials – for example by pouring sand into a container – then any possible arrangement of the grains within a certain volume will occur with the same probability.

This is the analogue of the assumption that is at the heart of equilibrium statistical mechanics – that all states with the same energy occur with equal probability. As a result the Edwards hypothesis offered a way for researchers to develop a statistical mechanics framework for granular materials, which has been an area of intense activity in the last couple of decades.

But the hypothesis was impossible to test – not least because above a handful of grains, the number of possible arrangements becomes unfathomably huge. Edwards himself died in 2015, with his theory still the subject of heated scientific debate.

Now, Martiniani and colleagues have been able to put his conjecture to a direct test, and to their surprise they found that it broadly holds true. Provided that the grains are at the point where they have just jammed together (or are just about to separate), all possible configurations are indeed equally likely.

Helpfully, this critical point – known as the jamming transition – is also the point of practical significance for many of the granular materials used in industry. Although Martiniani modelled a system comprising soft spheres, a bit like sponge tennis balls, many granular materials are hard grains that cannot be compressed further once in a packed state.

“Apart from being a very beautiful theory, this study gives us the confidence that Edwards’ framework was correct,” Martiniani said. “That means that we can use it as a lens through which to look at a whole range of related problems.”

Aside from informing existing processes that involve granular materials, there is a wider significance to better understanding their mechanics. In physics, a “system” is anything that involves discrete particles operating as part of a wider network. Although bigger in scale, the way in which icebergs function as part of an ice floe, or the way that individual vehicles move within a flow of traffic (and indeed sometimes jam), can be studied using a similar theoretical basis.

Martiniani’s study was undertaken during his PhD, while he was a Gates Scholar, under the supervision of Professor Daan Frenkel from the Department of Chemistry. It built on earlier research in which he developed new methods for calculating the probability of granular systems packing into different configurations, despite the vast numbers involved. In work published last year, for example, he and colleagues used computer modelling to work out how many ways a system containing 128 tennis balls could potentially be arranged. The answer turned out to be ten unquadragintilliard – a number so huge that it vastly exceeds the total number of particles in the universe.

In the new study, the researchers employed a sampling technique which attempts to compute the probability of different arrangements of grains without actually looking at the frequency with which these arrangements occur. Rather than taking an average from random samples, the method involves calculating the limits of the possibility of specific arrangements, and then calculates the overall probability from this.

The team applied this to a computer model of 64 soft spheres – an imaginary system which could therefore be “over-compressed” after reaching the jamming transition point. In an over-compressed state, the different arrangements were found to have different probabilities of occurrence. But as the system decompressed to the point of the jamming transition, at which the grains were effectively just touching, the researchers found that all probabilities became equal – exactly as Edwards predicted.

“In 1989, we didn’t really have the means of studying whether Edwards was right or not,” Martiniani added. “Now that we do, we can understand more about how granular materials work; how they flow, why they get stuck, and how we can use and manage them better in a whole range of different situations.”

The study, Numerical test of the Edwards conjecture shows that all packings become equally probable at jamming is published in the journal Nature Physics. DOI: 10.1038/nphys4168.

Germans have been stereotyped as being industrious and punctual, but also as being more likely to be anxious and worried, a phenomenon described as ‘German Angst’. Former German Chancellor Helmut Schmidt, widely regarded as one of Germany’s leading post-war intellectuals, once claimed, “The Germans have a tendency to be afraid. This has been part of their consciousness since the end of the Nazi period and the war”.

This personality type is characterised by high levels of neurotic personality traits (more likely to be in a negative emotional state), as opposed to traits of openness, agreeableness, extraversion, or conscientiousness, which together make up the ‘Big Five’ personality traits. It has been suggested that the heavy bombing of German cities in World War II, and the resulting destruction and trauma experienced by residents, may have been a contributory factor in this proposed higher incidence of neurotic traits.

In a study published this week in European Journal of Personality, an international team of researchers from the UK, Germany, USA, and Australia, analysed the neurotic personality traits and mental health of over 33,500 individuals across 89 regional German cities that experienced wartime bombing, and investigated whether people in cities that experienced higher levels of bombing were more likely to display neurotic traits. The researchers measured neurotic traits using the Big Five Inventory personality test as part of an online questionnaire, and focused on measures of neuroticism, anxiety, and depression.

“If the idea of ‘German Angst’ is true, then we’d expect people from cities that were heavily bombed during the war to be more anxious and less resilient to new stresses such as economic hardship,” says study author Dr Jason Rentfrow from the Department of Psychology, University of Cambridge. “Ours is the first study to investigate this link.”

The researchers found that in fact, residents of heavily bombed cities were less likely to display neurotic traits, suggesting that wartime bombing is not a factor in German Angst. The results indicate that residents of heavily bombed German cities instead recorded higher levels of mental resilience and were better able to cope in times of stress.

“We’ve seen from other studies that when people experience difficulties in life, these can provide them with a broader perspective on things and perhaps make more trivial stresses seem unimportant,” explains Dr Rentfrow. “It’s possible that this is what we are seeing here.”

The researchers also looked at how Germany compared to 107 other countries for neurotic traits, to see whether there really was evidence of ‘German Angst’. They found that Germany ranks 20th, 31st, and 53rd for depression, anxiety, and neuroticism respectively. Additionally, other countries that have experienced significant trauma due to warfare, such as Japan, Afghanistan, and Vietnam, also did not score highly for neurotic traits, further suggesting that such traumatic events are not associated with increased neuroticism.

“Germany didn’t stand out as high in anything resembling angst compared with other countries, which suggests that maybe this stereotype of ‘German Angst’ isn’t entirely valid,” says Dr Rentfrow. “Clearly we need to be careful about national stereotypes.”

The researchers emphasise that their findings show only an association, and that this data does not show whether more severe bombing caused greater mental resilience, or whether other factors were at play.

Although this research may have implications for other war-torn countries, including the current situation in Syria cities, the study did not investigate potential neuroticism or resilience in these countries, so no wider conclusions can be drawn from this data.

Study participants filled out online questionnaires provided by the global Gosling-Potter Internet Project, including 44 questions to assess their personality and mental state. Of the sample, just under 60% were female and the mean age was 30 years old. Almost all (96%) of the respondents were White/Caucasian while just under one in three (30%) had a bachelor’s degree or higher, and overall the sample was broadly representative of the populations of the cities assessed. Although the researchers tried to control for the movement of people between different cities, there were limitations with the data available from the online survey and so this movement may have affected the results.

The data also could not tell whether increased resilience was associated with a recent event, or whether it was associated with an event from many years or even decades ago. However, there is broader literature to support the notion of traumas increasing resilience in individuals, and more research in this area would shed further light on the relationship and potential mechanisms at play.