Category: Science News

{With data rates of more than 2 gigabits per second, new approach in photodetection could simplify free-space optical communication.}

In an advance that could one day make light-based wireless communications ubiquitous, researchers have demonstrated a conceptually new approach for detecting optical communication signals traveling through the air.

Today’s high-speed wired communication networks use lasers to carry information through optical fibers, but wireless networks are currently based on radio frequencies or microwaves. In an advance that could one day make light-based wireless communications ubiquitous, researchers from Facebook Inc.’s Connectivity Lab have demonstrated a conceptually new approach for detecting optical communication signals traveling through the air.

The team described the new technology, which could pave the way for fast optical wireless networks capable of delivering internet service to far-flung places, in Optica, The Optical Society’s journal for high impact research.

Bridging the Digital Divide

Facebook’s Connectivity Lab develops technologies aimed at providing affordable internet services to the approximately 4 billion people in the world who cannot currently access it. “A large fraction of people don’t connect to the internet because the wireless communications infrastructure is not available were they live, mostly in very rural areas of the world,” said Tobias Tiecke, who leads the research team. “We are developing communication technologies that are optimized for areas where people live far apart from each other.”

Light-based wireless communication, also called free-space optical communications, offers a promising way to bring the internet to areas where optical fibers and cell towers can be challenging to deploy in a cost-effective way. Using laser light to carry information across the atmosphere can potentially offer very high bandwidths and data capacity, but one of the primary challenges has been how to precisely point a very small laser beam carrying the data at a tiny light detector that is some distance away.

In the new study, Facebook researchers demonstrate a method for using fluorescent materials instead of traditional optics to collect light and concentrate it onto a small photodetector. They combined this light collector, which features 126 square centimeters of surface that can collect light from any direction, with existing telecommunications technology to achieve data rates of more than 2 gigabits-per-second (Gbps).

“We demonstrated the use of fluorescent optical fibers that absorb one color of light and emit another color,” said Tiecke. “The optical fibers absorb light coming from any direction over a large area, and the emitted light travels inside the optical fiber, which funnels the light to a small, very fast photodetector.”

Fast Communication Needs Fast Detectors

A high-speed free-space optical network requires very fast detectors to receive the laser light carrying information. But speed must be balanced against size; although larger detectors make an easier target to hit with a beam of laser light that’s traveling through the air, increasing the size of a detector makes it slower.

A combination of optics and mechanical systems can be used to track the position of the detector and point it to the laser, but these approaches add quite a bit of complexity. The new light collector uses plastic optical fibers containing organic dye molecules that absorb blue light and emit green light. This setup replaces the classical optics and motion platform typically required to point the light to the collection area.

“The fact that these fluorescent optical fibers emit a different color than they absorb makes it possible to increase the brightness of the light entering the system,” said Tiecke. “This approach has been used in luminescent concentrators for solar light harvesting, where the speed of the color conversion doesn’t matter. We showed that the same concept can be used for communication to circumvent pointing and tracking problems while accomplishing very high speeds.”

The fast speeds are possible because less than 2 nanoseconds lapse between the blue light absorption and the green light emission. In addition, by incorporating a signal modulation method called orthogonal frequency division multiplexing, or OFDM, the researchers transmitted more than 2 Gbps despite the system’s bandwidth of 100 MHz. OFDM is a method of encoding digital data so that multiple data streams can be transmitted at once. Although it is commonly used for wired and wireless communication, it is not typically used with laser communication.

“We achieved such high data rates using commercially available materials that are not designed for communications applications,” said Tiecke. “We want to get other groups interested in developing materials that are tailored for communications applications.”

If materials were developed that operate in the infrared part of the spectrum, which would be invisible to people, and were even faster than the blue/green light system, the new approach could theoretically allow free-space optical data rates of more than 10 Gbps, Tiecke said.

Gathering Light from all Directions

In the Optica paper, the researchers demonstrate a light-bulb shaped light collector made from a bundle of fluorescent optical fibers. Although many shapes are possible, the light-bulb shape offers a very large bandwidth and omnidirectional sensitivity, which means it would work with mobile devices that move around with respect to the transmitter. The researchers also demonstrated that this geometry can gather light from an area as large as 126 square centimeters, making it less sensitive to alignment.

“Our detector absorbs the same amount of power and gets the same communication signal through independently of the alignment,” said Tiecke.

In addition to working with partners to develop new materials, the research team is also planning to move this technology out of the lab by developing a prototype that could be tested in a real-world situation. “We are investigating the feasibility of a commercial product,” said Tiecke. “This is a very new system, and there is a lot of room for future development.”

{Scientists have shed light on why life on Earth took millions of years to recover from the greatest mass extinction of all time.}

The study provides fresh insight into how Earth’s oceans became starved of oxygen in the wake of the event 252 million years ago, delaying the recovery of life by five million years.

Findings from the study are helping scientists to better understand how environmental change can have disastrous consequences for life on Earth.

The Permian-Triassic Boundary extinction wiped out more than 90 per cent of marine life and around two thirds of animals living on land. During the recovery period, Earth’s oceans became starved of oxygen — conditions known as anoxia.

Previous research suggested the mass extinction and delayed recovery were linked to the presence of anoxic waters that also contained high levels of harmful compounds known as sulphides.

However, researchers say anoxic conditions at the time were more complex, and that this toxic, sulphide-rich state was not present throughout all the world’s oceans.

The team, led by researchers at the University of Edinburgh, used precise chemical techniques to analyse rocks unearthed in Oman that were formed in an ancient ocean around the time of the extinction.

Data from six sampling sites, spanning shallow regions to the deeper ocean, reveal that while the water was lacking in oxygen, toxic sulphide was not present. Instead, the waters were rich in iron.

The finding suggests that iron-rich, low oxygen waters were a major cause of the delayed recovery of marine life following the mass extinction.

The study also shows how oxygen levels varied at different depths in the ocean. While low oxygen levels were present at some depths and restricted the recovery of marine life, shallower waters contained oxygen for short periods, briefly supporting diverse forms of life.

The precise cause of the long recovery period remains unclear, but increased run-off from erosion of rocks on land — caused by high global temperatures — likely triggered anoxic conditions in the oceans, researchers say.

The study, published in the journal Nature Communications, was funded by the Natural Environment Research Council and the International Centre for Carbonate Reservoirs. The work is a contribution to the UNESCO International Geoscience Programme. It was carried out in collaboration with the Universities of Leeds, Gratz, Bremen and Vienna University.

Dr Matthew Clarkson, of the University of Edinburgh’s School of GeoSciences, who led the study, said: “We knew that lack of oxygen in the oceans played a key role in the extinction and recovery processes, but we are still discovering how exactly it was involved. Our findings about the chemistry of the ocean at the time provide us with a clearer picture of how this complex process delayed the recovery of life for so long.”

Professor Simon Poulton, of the University of Leeds, who co-authored the study, said: “The neat point about this study is that it shows just how critical an absence of oxygen, rather than the presence of toxic sulphide, was to the survival of animal life. We found that marine organisms were able to rapidly recolonise areas where oxygen became available.”

{Human intelligence is being defined and measured for the first time ever. It turns out that the more variable a brain is, and the more its different parts frequently connect with each other, the higher a person’s IQ and creativity are.}

Human intelligence is being defined and measured for the first time ever, by researchers at the University of Warwick.

Led by Professor Jianfeng Feng in the Department of Computer Science, studies at Warwick and in China have been recently undertaken to quantify the brain’s dynamic functions, and identify how different parts of the brain interact with each other at different times — namely, to discover how intellect works.

Professor Jianfeng finds that the more variable a brain is, and the more its different parts frequently connect with each other, the higher a person’s IQ and creativity are.

More accurate understanding of human intelligence could lead to future developments in artificial intelligence (AI). Currently, AI systems do not process the variability and adaptability that is vital, as evidenced by Professor Jianfeng’s research, to the human brain for growth and learning. This discovery of dynamic functions inside the brain could be applied to the construction of advanced artificial neural networks for computers, with the ability to learn, grow and adapt.

This study may also have implications for a deeper understanding of another largely misunderstood field: mental health. Altered patterns of variability were observed in the brain’s default network with schizophrenia, autism and Attention Deficit Hyperactivity Disorder (ADHD) patients. Knowing the root cause of mental health defects brings scientists exponentially closer to treating and preventing them in the future.

Using resting-state MRI analysis on thousands of people’s brains around the world, the research has found that the areas of the brain which are associated with learning and development show high levels of variability, meaning that they change their neural connections with other parts of the brain more frequently, over a matter of minutes or seconds. On the other hand, regions of the brain which aren’t associated with intelligence — the visual, auditory, and sensory-motor areas — show small variability and adaptability.

Professor Jianfeng Feng commented that new technology has made it possible to conduct this trail-blazing study: “human intelligence is a widely and hotly debated topic and only recently have advanced brain imaging techniques, such as those used in our current study, given us the opportunity to gain sufficient insights to resolve this and inform developments in artificial intelligence, as well as help establish the basis for understanding and diagnosis of debilitating human mental disorders such as schizophrenia and depression.”

{Children as young as 9 months-old prefer to play with toys specific to their own gender, according to a new study. The research suggests the possibility that boys and girls follow different developmental trajectories with respect to selection of gender-typed toys and that there is both a biological and a developmental-environmental components to the sex differences seen in object preferences.}

Children as young as 9 months-old prefer to play with toys specific to their own gender, according to a new study from academics at City University London and UCL.

The paper, which is published in the journal of Infant and Child Development, shows that in a familiar nursery environment significant sex differences were evident at an earlier age than gendered identity is usually demonstrated.

The research therefore suggests the possibility that boys and girls follow different developmental trajectories with respect to selection of gender-typed toys and that there is both a biological and a developmental-environmental components to the sex differences seen in object preferences.

To investigate the gender preferences seen with toys, the researchers observed the toy preferences of boys and girls engaged in independent play in UK nurseries, without the presence of a parent. The toys used in the study were a doll, a pink teddy bear and a cooking pot for girls, while for boys a car, a blue teddy, a digger and a ball were used.

The 101 boys and girls fell into three age groups: 9 to 17 months, when infants can first demonstrate toy preferences in independent play (N=40); 18 to 23 months, when critical advances in gender knowledge occur (N=29); and 24 to 32 months, when knowledge becomes further established (N=32).

Stereotypical toy preferences were found for boys and girls in each of the age groups, demonstrating that sex differences in toy preference appear early in development. Both boys and girls showed a trend for an increasing preference with age for toys stereotyped for boys.

Speaking about the study, Dr Brenda Todd, a senior lecturer in psychology at City University said, “Sex differences in play and toy choice are of interest in relation to child care, educational practice and developmental theory. Historically there has been uncertainty about the origins of boys’ and girls’ preferences for play with toys typed to their own sex and the developmental processes that underlie this behaviour. As a result we set out to find out whether a preference occurs and at what age it develops.

“Biological differences give boys an aptitude for mental rotation and more interest and ability in spatial processing, while girls are more interested in looking at faces and better at fine motor skills and manipulating objects. When we studied toy preference in a familiar nursery setting with parents absent, the differences we saw were consistent with these aptitudes. Although there was variability between individual children, we found that, in general, boys played with male-typed toys more than female-typed toys and girls played with female-typed toys more than male-typed toys.

“Our results show that there are significant sex differences across all three age groups, with the finding that children in the youngest group, who were aged between 9-17months when infants are able to crawl or walk and therefore make independent selections, being particularly interesting; the ball was a favourite choice for the youngest boys and the youngest girls favoured the cooking pot.”

{Dr. Tyler Lyson co-authors paper about turtle shells as a burrowing tool, not for protection as previously thought}

Scientists have discovered the real reason turtles have shells. While many thought turtle shells were for protection, new findings show that the shells were actually for digging underground to escape the harsh South African environment where these early proto turtles lived.

It is common knowledge that the modern turtle shell is largely used for protection. No other living vertebrate has so drastically altered its body to form such an impenetrable protective structure as the turtle. However, a new study by an international group of paleontologists suggests that the broad ribbed proto shell on the earliest partially shelled fossil turtles was initially an adaptation, for burrowing underground, not for protection. Paleontologist Tyler Lyson from the Denver Museum of Nature & Science is among the scientists that helped make this discovery.

“Why the turtle shell evolved is a very Dr. Seuss-like question and the answer seems pretty obvious — it was for protection,” said Dr. Lyson, lead author of Fossorial Origin of the Turtle Shell, which was released today by Current Biology. But just like the bird feather did not initially evolve for flight, the earliest beginnings of the turtle shell was not for protection but rather for digging underground to escape the harsh South African environment where these early proto turtles lived.”

The early evolution of the turtle shell had long puzzled scientists. “We knew from both the fossil record and observing how the turtle shell develops in modern turtles that one of the first major changes toward a shell was the broadening of the ribs,” said Dr. Lyson. While distinctly broadened ribs may not seem like a significant modification, it has a serious impact on both breathing and speed in quadrupedal animals. Ribs are used to support the body during locomotion and play a crucial role in ventilating the lungs. Distinctly broadened ribs stiffen the torso, which shortens an animals stride length and slows it down, interfering with breathing.

“The integral role of ribs in both locomotion and breathing is likely why we don’t see much variation in the shape of ribs,” said Dr. Lyson. “Ribs are generally pretty boring bones. The ribs of whales, snakes, dinosaurs, humans, and pretty much all other animals look the same. Turtles are the one exception, where they are highly modified to form the majority of the shell.”

A big breakthrough came with the discovery of several specimens of the oldest (260- million-year-old) partially shelled proto turtle, Eunotosaurus africanus, from the Karoo Basin of South Africa. Several of these specimens were discovered by two of the study’s coauthors, Drs. Roger Smith and Bruce Rubidge from the University of Witwatersrand in Johannesburg. But the most important specimen was found by a then 8-year-old South African boy on his father’s farm in the Western Cape of South Africa. This specimen, which is about 15 cm long, comprises a well preserved skeleton together with the fully articulated hands and feet.

“I want to thank Kobus Snyman and shake his hand because without Kobus both finding the specimen and taking it to his local museum, the Fransie Pienaar Museum in Prince Albert, this study would not have been possible,” said Dr. Lyson.

{Daily infusions with a chemical commonly associated with feelings of happiness were shown to increase calcium levels in the blood of Holstein cows and the milk of Jersey cows that had just given birth. The results, published in the Journal of Endocrinology, could lead to a better understanding of how to improve the health of dairy cows, and keep the milk flowing.}

Demand is high for milk rich in calcium: there is more calcium in the human body than any other mineral, and in the West dairy products such as milk, cheese and yoghurt are primary sources of calcium. But this demand can take its toll on milk-producing cows: roughly 5-10% of the North American dairy cow population suffers from hypocalcaemia — in which calcium levels are low. The risk of this disease is particularly high immediately before and after cows give birth.

Hypocalcaemia is considered a major health event in the life of a cow. It is associated with immunological and digestive problems, decreased pregnancy rates and longer intervals between pregnancies. These all pose a problem for dairy farmers, whose profitability depends upon regular pregnancies and a high-yield of calcium-rich milk.

Whilst there has been research into the treatment of hypocalcaemia, little research has focused on prevention. In rodents it has been shown that serotonin (a naturally-occurring chemical commonly associated with feelings of happiness) plays a role in maintaining calcium levels; based on this, a team from the University of Wisconsin-Madison, led by Dr Laura Hernandez, investigated the potential for serotonin to increase calcium levels in both the milk and blood of dairy cows. The team infused a chemical that converts to serotonin into 24 dairy cows, in the run up to giving birth. Half the cows were Jersey and half were Holstein — two of the most common breeds. Calcium levels in both the milk and circulating blood were measured throughout the experiment.

Whilst serotonin improved the overall calcium status in both breeds, this was brought about in opposite ways. Treated Holstein cows had higher levels of calcium in their blood, but lower calcium in their milk (compared to controls). The reverse was true in treated Jersey cows and the higher milk calcium levels were particularly obvious in Jerseys at day 30 of lactation — suggesting a role for serotonin in maintaining levels throughout lactation.

“By studying two breeds we were able to see that regulation of calcium levels is different between the two,” says Laura Hernandez. “Serotonin raised blood calcium in the Holsteins, and milk calcium in the Jerseys. We should also note that serotonin treatment had no effect on milk yield, feed intake or on levels of hormones required for lactation.”

The next steps are to investigate the molecular mechanism by which serotonin regulates calcium levels, and how this varies between breeds.

“We would also like to work on the possibility of using serotonin as a preventative measure for hypocalcaemia in dairy cows,” continues Laura Hernandez, “That would allow dairy farmers to maintain the profitability of their businesses, whilst making sure their cows stay healthy and produce nutritious milk.”

{Companions to warm Jupiters evidence they formed where we find them.}

After analyzing four years of Kepler space telescope observations, astronomers from the University of Toronto have given us our clearest understanding yet of a class of exoplanets called “Warm Jupiters,” showing that many have unexpected planetary companions.

The team’s analysis, published July 10th in the Astrophysical Journal, provides strong evidence of the existence of two distinct types of Warm Jupiters, each with their own formation and dynamical history.

The two types include those that have companions and thus, likely formed where we find them today; and those with no companions that likely migrated to their current positions.

According to lead-author Chelsea Huang, a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, “Our findings suggest that a big fraction of Warm Jupiters cannot have migrated to their current positions dynamically and that it would be a good idea to consider more seriously that they formed where we find them.”

Warm Jupiters are large, gas-giant exoplanets — planets found around stars other than the Sun. They are comparable in size to the gas-giants in our Solar System. But unlike the Sun’s family of giant planets, Warm Jupiters orbit their parent stars at roughly the same distance that Mercury, Venus and the Earth circle the Sun. They take 10 to two hundred days to complete a single orbit.

Because of their proximity to their parent stars, they are warmer than our system’s cold gas giants — though not as hot as Hot Jupiters, which are typically closer to their parent stars than Mercury.

It has generally been thought that Warm Jupiters didn’t form where we find them today; they are too close to their parent stars to have accumulated large, gas-giant-like atmospheres. So, it appeared likely that they formed in the outer reaches of their planetary systems and migrated inward to their current positions, and might in fact continue their inward journey to become Hot Jupiters. On such a migration, the gravity of any Warm Jupiter would have disturbed neighbouring or companion planets, ejecting them from the system.

But, instead of finding “lonely,” companion-less Warm Jupiters, the team found that 11 of the 27 targets they studied have companions ranging in size from Earth-like to Neptune-like.

“And when we take into account that there is more analysis to come,” says Huang, “the number of Warm Jupiters with smaller neighbours may be even higher. We may find that more than half have companions.”

1. Launched in 2009, the Kepler space telescope has discovered over 2000 exoplanets orbiting distant stars located in a patch of sky in the constellation Cygnus (and the number is rising as exoplanet candidates are confirmed as actual exoplanets through follow-up observations). Kepler cannot see an exoplanet orbiting its parent star; they are too far away, too small, and their parent stars too bright for any telescope to resolve them. Instead, Kepler measures the brightness of a star with enough accuracy to detect the slight decrease in brightness caused by an exoplanet moving in front of it.

2. In addition to the insight into Warm Jupiters, the analysis also provided the most conclusive evidence yet that Hot Jupiters lack companions and likely migrated to their current orbits. One exception is the recently discovered HJ known as WASP-47b, which was found to have companions.

3. NASA’s Ames Research Center in Moffett Field, California, manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.

{While measuring brain activity with magnetic resonance imaging during blood pressure trials, UCLA researchers found that men and women had opposite responses in the right front of the insular cortex, a part of the brain integral to the experience of emotions, blood pressure control and self-awareness.}

The insular cortex has five main parts called gyri serving different roles.The researchers found that the blood pressure response in the front right gyrus showed an opposite pattern in men and women, with men showing a greater right-sided activation in the area while the women showed a lower response.

“This is such a critical brain area and we hadn’t expected to find such strong differences between men and women’s brains,” said Paul Macey, the study’s lead author. “This region, the front-right insula, is involved with stress and keeping heart rate and blood pressure high. It’s possible the women had already activated this region because of psychological stress, so that when they did the physical test in the study, the brain region could not activate any more. However, it’s also possible that this region is wired differently in men and women.”

“We have always thought that the ‘normal’ pattern was for this right-front insula region to activate more than other areas, during a task that raises blood pressure,” added Macey. “However, since most earlier studies were in men or male animals, it looks like this ‘normal’ response was only in men. The healthy response in women seems to be a lower right-sided activation.”

{{Background}}

Most studies on differences in brain functions between men and women have looked at psychological performance.

In previous studies, the UCLA researchers had seen differences in heart rate and blood brain flow during blood pressure changes in men and women with obstructive sleep apnea and wanted to see if cardiovascular responses in brain areas were different in healthy men and women.

Method

In this study, researchers from the UCLA School of Nursing used the Valsalva maneuver — during which participants breathe hard out through a very small tube to raise blood pressure — to measure brain activity as it controls the blood pressure change.

{{Impact}}

“This raises several questions for us, such as why is there a difference in brain pattern and might it reflect differences in health issues for men and women, particularly in cardiovascular disease variations,” Macey said.

To find the answers, further study on this difference will be needed to gain a better understanding of susceptibility to disease, efficacy of drugs and even the course of normal development among all individuals, not just between men and women.

“We believe that differences in the structure and function of the insula in men and women might contribute to different clinical symptoms in some medical disorders,” Macey said.

{It’s of ‘profound’ importance to proper social functioning, researchers determine.}

In a startling discovery that raises fundamental questions about human behavior, researchers at the University of Virginia School of Medicine have determined that the immune system directly affects — and even controls — creatures’ social behavior, such as their desire to interact with others. So could immune system problems contribute to an inability to have normal social interactions? The answer appears to be yes, and that finding could have great implications for neurological conditions such as autism-spectrum disorders and schizophrenia.

“The brain and the adaptive immune system were thought to be isolated from each other, and any immune activity in the brain was perceived as sign of a pathology. And now, not only are we showing that they are closely interacting, but some of our behavior traits might have evolved because of our immune response to pathogens,” explained Jonathan Kipnis, PhD, chairman of UVA’s Department of Neuroscience. “It’s crazy, but maybe we are just multicellular battlefields for two ancient forces: pathogens and the immune system. Part of our personality may actually be dictated by the immune system.”

{{Evolutionary Forces at Work}}

It was only last year that Kipnis, the director of UVA’s Center for Brain Immunology and Glia, and his team discovered that meningeal vessels directly link the brain with the lymphatic system. That overturned decades of textbook teaching that the brain was “immune privileged,” lacking a direct connection to the immune system. The discovery opened the door for entirely new ways of thinking about how the brain and the immune system interact.

The follow-up finding is equally illuminating, shedding light on both the workings of the brain and on evolution itself. The relationship between people and pathogens, the researchers suggest, could have directly affected the development of our social behavior, allowing us to engage in the social interactions necessary for the survival of the species while developing ways for our immune systems to protect us from the diseases that accompany those interactions. Social behavior is, of course, in the interest of pathogens, as it allows them to spread.

The UVA researchers have shown that a specific immune molecule, interferon gamma, seems to be critical for social behavior and that a variety of creatures, such as flies, zebrafish, mice and rats, activate interferon gamma responses when they are social. Normally, this molecule is produced by the immune system in response to bacteria, viruses or parasites. Blocking the molecule in mice using genetic modification made regions of the brain hyperactive, causing the mice to become less social. Restoring the molecule restored the brain connectivity and behavior to normal. In a paper outlining their findings, the researchers note the immune molecule plays a “profound role in maintaining proper social function.”

“It’s extremely critical for an organism to be social for the survival of the species. It’s important for foraging, sexual reproduction, gathering, hunting,” said Anthony J. Filiano, PhD, Hartwell postdoctoral fellow in the Kipnis lab and lead author of the study. “So the hypothesis is that when organisms come together, you have a higher propensity to spread infection. So you need to be social, but [in doing so] you have a higher chance of spreading pathogens. The idea is that interferon gamma, in evolution, has been used as a more efficient way to both boost social behavior while boosting an anti-pathogen response.”

{{Understanding the Implications}}

The researchers note that a malfunctioning immune system may be responsible for “social deficits in numerous neurological and psychiatric disorders.” But exactly what this might mean for autism and other specific conditions requires further investigation. It is unlikely that any one molecule will be responsible for disease or the key to a cure, the researchers believe; instead, the causes are likely to be much more complex. But the discovery that the immune system — and possibly germs, by extension — can control our interactions raises many exciting avenues for scientists to explore, both in terms of battling neurological disorders and understanding human behavior.

“Immune molecules are actually defining how the brain is functioning. So, what is the overall impact of the immune system on our brain development and function?” Kipnis said. “I think the philosophical aspects of this work are very interesting, but it also has potentially very important clinical implications.”

{{Findings Published}}

Kipnis and his team worked closely with UVA’s Department of Pharmacology and the group of Vladimir Litvak, PhD, at the University of Massachusetts Medical School. Litvak’s team developed a computational approach to investigate the complex dialogue between immune signaling and brain function in health and disease. “Using this approach we predicted a role for interferon gamma, an important cytokine secreted by T lymphocytes, in promoting social brain functions,” Litvak said. “Our findings contribute to a deeper understanding of social dysfunction in neurological disorders, such as autism and schizophrenia, and may open new avenues for therapeutic approaches.”

The findings have been published online in the journal Nature. The article was written by Filiano, Yang Xu, Nicholas J. Tustison, Rachel L. Marsh, Wendy Baker, Igor Smirnov, Christopher C. Overall, Sachin P. Gadani, Stephen D. Turner, Zhiping Weng, Sayeda Najamussahar Peerzade, Hao Chen, Kevin S. Lee, Michael M. Scott, Mark P. Beenhakker, Litvak and Kipnis.

This work was supported by the National Institutes of Health (grants No. AG034113, NS081026 and T32-AI007496) and the Hartwell Foundation.

{Reciprocal food-sharing is more prevalent in stable hunter-gatherer camps, shows new UCL research that sheds light on the evolutionary roots of human cooperation.}

The research explores patterns of food-sharing among the Agta, a population of Filipino hunter-gatherers. It finds that reciprocal food-sharing is more prevalent in stable camps (with fewer changes in membership over time); while in less stable camps individuals acquire resources by taking from others — known as ‘demand sharing’.

Exploring social dynamics in the last remaining groups of present day hunter-gatherers is essential for understanding the factors that shaped the evolution of our widespread cooperation, especially with non-kin.

The study, published in the Royal Society journal Open Science, is the first to report a real-world association between patterns of cooperation and group stability.

First author of the study, Daniel Smith (UCL Anthropology), said: “Cooperation between unrelated individuals is rare in animals, yet extensive among humans. Reciprocity — the principle of “you scratch my back, I scratch yours” — may explain this non-kin cooperation, yet requires stable groups and repeated interactions to evolve.

“Our research shows that hunter-gatherer cooperation is extremely flexible — reflecting either reciprocity or demand sharing depending on the frequency of repeated interactions between camp members.”

The authors looked at two types of food-sharing data. Firstly, details of actual food-sharing from six Agta camps were examined to explore whether differences in camp stability predicted patterns of food-sharing. Secondly, games were also conducted in which individuals were asked to distribute resources between themselves and other camp-mates. These games were conducted with 324 Agta over 18 separate camps.

In one of the games, participants were shown their own picture, along with other randomly selected adults from camp. They were then given a number of small wooden tokens, each representing 125g rice, equal to the number of camp-mates’ photos. Not every picture including the subject’s could end up with rice on it, introducing a social dilemma regarding whether to share, as it would be impossible for everyone to receive rice. Participants then decided, token by token, whether to keep the rice for themselves, or to give to a camp-mate.

The results showed that, firstly, stable camps were more likely to display reciprocity in the actual food-sharing analyses. Patterns of food-sharing in unstable camps were not reciprocal, consistent with demand sharing, whereby individuals take resources from others rather than being given them. Secondly, individuals from more stable camps were increasingly likely to give resources to others and less likely to take resources in the games.

Despite differences in cooperation, individuals from both stable and unstable camps received resources from others. This distribution of resources among camp-mates is crucial for hunter-gatherers’ survival. As foraging success is variable it is likely that, on any given day, an individual may return to camp with no resources. Food-sharing is therefore essential to reduce the likelihood of individuals going without resources for extended lengths of time.

Last author, Professor Ruth Mace (UCL Anthropology), added: “Food sharing and cooperation are at the centre of hunter-gatherers lifestyle. No other Apes share food or cooperate to the extent that humans do. A complex network of sharing and cooperation exists within camps and between camps in different hunter-gatherer groups, regulated by social rules, friendship ties, food taboos, kinship and supernatural beliefs. Sharing is a crucial adaptation to hunter-gatherers’ lifestyles, central to their resilience — and central to the evolution of humankind.”