Saturday, October 31, 2015

Hope your Halloween is a 'real' scream

Janet Leigh belts one out during the famous shower scene in "Psycho."

Ben Guarino writes about the mysteries of screaming for Inverse. Below is an excerpt:

"We scream when we're excited or happy; we scream when we're fearful or in pain; we scream when we are exasperated; we scream when we're charging into battle; we scream during sex. But we rarely stop to wonder what those screams, even the ones that erupt from us, signify or if they can be differentiated. Emory University psychologist Harold Gouzoules thinks in those terms, but despite being probably the world's foremost expert on screaming, he doesn't speak in absolutes. For decades, Gouzoules studied screams in macaques and other nonhuman primates. He's only worked with Homo sapiens for three years and answers to even the most basic research questions remain elusive."

Read Guarino's interview with Gouzoules in Inverse.

Many species scream, but humans are the masters of the craft, notes Alistair Gee in the New Yorker. Gouzoules "speculates that this is because we humans are more sophisticated communicators in general: if our brains can grasp the fifteen or so cases in the Finnish language, high-level screaming ought to be a breeze."

Read the New Yorker story here.

The psychology of screams

Thursday, October 29, 2015

BRAIN Initiative grant to fund study of sensory-motor circuitry

"We hope that our project will lead to an algorithm for basal ganglia and motor control circuits involved in movement control," says Emory neuroscientist Dieter Jaeger. (Emory Photo/Video)

To move or not to move. That is the question the brain grapples with routinely as it receives a stimulus, decides whether to direct the body to respond with an action, then sends the appropriate signals to control the behavior. It is a common and fundamental process, but we know little about how the brain actually does it.

“New technology allows us to monitor brain activity at high spatial and temporal resolution, and do so over long periods of time,” says Dieter Jaeger, a neuroscientist in Emory University’s Department of Biology. “This technology is finally opening the door to address questions related to the circuits involved in coordinating the relationship between neural sensing and physical action.”

Jaeger recently received a grant from the National Institutes of Health BRAIN Initiative to explore these questions about neural circuitry. He shares the $1.7 million award with Garrett Stanley, a neuroscientist in the Emory-Georgia Tech Wallace H. Coulter Department of Biomedical Engineering (BME). The BRAIN Initiative (Brain Research through Advancing Innovative Neurotechnologies) was launched by President Obama in 2014 as part of a widespread effort to gain fundamental insights for treating a range of brain disorders.

Areas of the brain involved in sensory input and movement include the basal ganglia, the thalamus and the cortex. What’s less clear is how neural activity flows through these areas, connecting a sensation to a decision to make a movement. Debilitating and difficult to treat neurological disorders like Parkinson’s disease, Huntington’s disease and dystonia are caused by dysfunction of this circuitry.

The Stanley lab specializes in tactile sensing and information processing, while the Jaeger lab is focused on motor and muscle coordination and control.

Image from the cover of the NIH brochure, "The BRAIN Initiative."

For their BRAIN project, Stanley and Jaeger are combining their two areas of expertise and experimenting with a mouse model. Techniques such as genetic voltage sensing will allow them to gain images of cortical electrical activity, with millisecond precision.

“We understand a lot about the biology of the brain,” Jaeger says. “The challenge now is to move beyond biology to algorithm. We hope that our project will lead to an algorithm for basal ganglia and motor cortical circuits involved in movement control.”

Such an algorithm could generate a computer program to simulate activity of the brain. “We could use this computer program to make predictions and run simulations,” Jaeger says. “It would be a great tool to test our understanding and compare against data. It’s important, because without such a tool, many clinical approaches to brain malfunction are groping in the dark.”

“Gaining basic insights into motor circuit function may reveal new possibilities for the treatment of neural diseases, as well as a better understanding of deep brain stimulation treatments already in use,” adds Stanley.

The project grew out of another collaboration between Jaeger and Stanley. They are also co-principal investigators of an NIH-sponsored training grant in computational neuroscience, which targets a new generation of scientists bound together through questions about how the brain computes.

 “Through this interaction, Dieter and I got to know each other better, started to talk more science, and eventually came up with this project,” Stanley says.

Wednesday, October 14, 2015

Mathematicians find 'magic key' to drive Ramanujan's taxi-cab number

A British taxi numbered 1729 sparked the most famous anecdote in math and led to the origin of "taxi-cab numbers." The incident is included in an upcoming biopic of Ramanujan, "The Man Who Knew Infinity," featuring Dev Patel in the lead role. Above is a still from the movie. (Pressman Films.)

By Carol Clark

Taxi-cab numbers, among the most beloved integers in math, trace their origins to 1918 and what seemed like a casual insight by the Indian genius Srinivasa Ramanujan. Now mathematicians at Emory University have discovered that Ramanujan did not just identify the first taxi-cab number – 1729 – and its quirky properties. He showed how the number relates to elliptic curves and K3 surfaces – objects important today in string theory and quantum physics.

“We’ve found that Ramanujan actually discovered a K3 surface more than 30 years before others started studying K3 surfaces and they were even named,” says Ken Ono, a number theorist at Emory. “It turns out that Ramanujan’s work anticipated deep structures that have become fundamental objects in arithmetic geometry, number theory and physics.”

Ono and his graduate student Sarah Trebat-Leder are publishing a paper about these new insights in the journal Research in Number Theory. Their paper also demonstrates how one of Ramanujan’s formulas associated with the taxi-cab number can reveal secrets of elliptic curves.

“We were able to tie the record for finding certain elliptic curves with an unexpected number of points, or solutions, without doing any heavy lifting at all,” Ono says. “Ramanujan’s formula, which he wrote on his deathbed in 1919, is that ingenious. It’s as though he left a magic key for the mathematicians of the future. All we had to do was recognize the key’s power and use it to drive solutions in a modern context.”

“This paper adds yet another truly beautiful story to the list of spectacular recent discoveries involving Ramanujan’s notebooks,” says Manjul Bhargava, a number theorist at Princeton University. “Elliptic curves and K3 surfaces form an important next frontier in mathematics, and Ramanujan gave remarkable examples illustrating some of their features that we didn’t know before. He identified a very special K3 surface, which we can use to understand a certain special family of elliptic curves. These new examples and insights are certain to spawn further work that will take mathematics forward.”

A close-up of the taxi-cab plate, in a scene from the upcoming movie, "The Man Who Knew Infinity." (Pressman Films.)

Ramanujan, a largely self-taught mathematician, seemed to solve problems instinctively and said his formulas came to him in the form of visions from a Hindu goddess. During the height of British colonialism, he left his native India to become a protégé of mathematician G.H. Hardy at Cambridge University in England.

By 1918, the British climate and war-time rationing had taken their toll on Ramanujan, who was suffering from tuberculosis. He lay ailing in a clinic near London when Hardy came to visit.

Wanting to cheer up Ramanujan, Hardy said that he had arrived in taxi number 1729 and described the number “as rather a dull one.” To Hardy’s surprise, Ramanujan sat up in bed and replied, “No, Hardy, it’s a very interesting number! It’s the smallest number expressible as the sum of two cubes in two different ways.”

Ramanujan, who had an uncanny sense for the idiosyncratic properties of numbers, somehow knew that 1729 can be represented as 1 cubed + 12 cubed and 9 cubed + 10 cubed, and no smaller positive number can be written in two such ways.

This incident launched the “Hardy-Ramanujan number,” or “taxi-cab number,” into the world of math. To date, only six taxi-cab numbers have been discovered that share the properties of 1729. (These are the smallest numbers which are the sum of cubes in n different ways. For n=2 the number is 1729.)

The original taxi-cab number 1729 is a favorite nerdy allusion in television sitcoms by Matt Groening. The number shows up frequently as an inside joke in episodes of “Futurama” and the “The Simpsons.”

But like much of Ramanujan’s discoveries, 1729 turned out to contain hidden meanings that make it much more than a charming mathematical oddity.

“This is the ultimate example of how Ramanujan anticipated theories,” Ono says. “When looking through his notes, you may see what appears to be just a simple formula. But if you look closer, you can often uncover much deeper implications that reveal Ramanujan’s true powers.”

Jeremy Irons portrays G. H. Hardy and Dev Patel plays Ramanujan in "The Man Who Knew Infinity." (Pressman Films.)

Much of Ono’s career is focused on unraveling Ramanujan mysteries. In 2013, during a trip to England to visit number theorists Andrew Granville and John Coates, Ono rummaged through the Ramanujan archive at Cambridge. He came across a page of formulas that Ramanujan wrote a year after he first pointed out the special qualities of the number 1729 to Hardy. By then, the 32-year-old Ramanujan was back in India but he was still ailing and near death.

“From the bottom of one of the boxes in the archive, I pulled out one of Ramanujan’s deathbed notes,” Ono recalls. “The page mentioned 1729 along with some notes about it. Andrew and I realized that he had found infinitely near misses for Fermat’s Last Theorem for exponent 3. We were shocked by that, and actually started laughing. That was the first tip-off that Ramanujan had discovered something much larger.”

Fermat’s Last Theorem is the idea that certain simple equations have no solutions – the sum of two cubes can never be a cube. Ramanujan used an elliptic curve – a cubic equation and two variables where the largest degree is 3 – to produce infinitely many solutions that were nearly counter examples to Fermat’s Last Theorem.

Elliptic curves have been studied for thousands of years, but only during the last 50 years have applications been found for them outside of mathematics. They are important, for example, for Internet cryptography systems that protect information like bank account numbers.

Ono had worked with K3 surfaces before and he also realized that Ramanujan had found a K3 surface, long before they were officially identified and named by mathematician André Weil during the 1950s. Weil named them in honor of three algebraic masters – Kummer, Kähler and Kodaira – and the mountain K2 in Kashmir.

Just as K2 is an extraordinarily difficult mountain to climb, the process of generalizing elliptic curves to find a K3 surface is considered an exceedingly difficult math problem.

Ono and Trebat-Leder put all the pieces in Ramanujan’s notes together to produce the current paper, illuminating his finds and translating them into a modern framework.

“Ramanujan was using 1729 and elliptic curves to develop formulas for a K3 surface,” Ono says. “Mathematicians today still struggle to manipulate and calculate with K3 surfaces. So it comes as a major surprise that Ramanujan had this intuition all along.”

Ramanujan is well-known in India, and among mathematicians worldwide. He may soon become more familiar to wider audiences through an upcoming movie, “The Man Who Knew Infinity,” by Pressman Films. Ono served as a math consultant for the movie, which stars Dev Patel as Ramanujan and Jeremy Irons as Hardy. (Both Ono and Bhargava are associate producers for the film.)

“Ramanujan’s life and work are both a great human story and a great math story,” Ono says. “And I’m glad that more people are finally going to get to enjoy it.”

Math shines with the stars in 'The Man Who Knew Infinity'
Doing math with movie stars
New theories reveal the nature of numbers 
Math theory gives glimpse into the magical mind of Ramanujan

Tuesday, October 13, 2015

Fungi at root of plant drugs that can help, or harm, sick monarch butterflies

Chemicals in milkweed plants can cure, or kill, sick monarchs, depending on the dosage and the species of the plant.

Previously, biologists discovered that butterflies use plant toxins as a drug to cure their offspring of parasitic infections. Now they’ve dug a little deeper and found that the fungi associated with the roots of milkweed plants change both the nutritional and medicinal chemistry of milkweed leaves.

“We found that these changes caused by the fungi affect the growth of a protozoan parasite, so that monarchs become sicker on some milkweed plants and healthier on others,” says Jaap de Roode, the Emory biologist whose lab led the study.

Proceedings of the Royal Society B published the results, which provide a more complete and complex picture of infectious disease ecology than before.

Most infectious diseases are studied as two-way interactions between one host and one pathogen. “Here, we show that interactions among species from four different biological kingdoms – animals, plants, fungi and protozoa – determine infectious disease risk,” says Leiling Tao, the lead author of the study and a post-doctoral fellow in the de Roode lab.

A monarch lays eggs. (Jaap de Roode.)
Arbuscular mycorrhizal fungi form a symbiotic relationship with more than 90 percent of terrestrial plants, making them a key player in community ecology – the concept of interspecies interactions within and across ecosystems. The microscopic fungi receive carbon from plants. In return, they provide the plants with water and nutrients, mostly phosphorus and nitrogen.

“It’s well known that these fungi are important to plants and provide a lot of services, such as helping them cope with different types of stresses,” Tao says. “What we didn’t know before was that they also affect host-parasite interaction in animals above the ground.”

The findings not only add to the understanding of disease ecology in general, they could be important to human health, since about half of new pharmaceuticals are derived from plants, says co-author Mark Hunter, a chemical ecologist at the University of Michigan.

De Roode and Hunter discovered in 2010 that female monarch butterflies infected with the parasite Ophryocystis elektroscirrha prefer to lay their eggs on species of milkweed that will make their caterpillars less sick. Monarchs appear to have evolved the ability to medicate their offspring by choosing milkweed plants with high levels of cardenolides, a class of toxins that appear to kill the parasites.

And the Hunter lab had shown that mycorrhizal fungi associated with milkweed roots affect the levels of cardenolides in the plants.

Monarch caterpillars feed exclusively on milkweed plants. (Photo by Jaap de Roode.)

For the current paper, the researchers conducted greenhouse experiments on six species of milkweed that produce varying amounts of cardenolides. The plants were grown either with no mycorrhizal fungi, with low levels, or with high levels.

Monarch caterpillars were fed leaves from the various milkweed plants and then exposed to the protozoan parasite. The results showed the fungi are associated with both the virulence of the parasite and the ability of the monarchs to resist infection and to survive if infected.

Dosage of the cardenolides is critical, Tao says. “In some species of milkweed, the presence of the fungi was beneficial for the caterpillars. In some species, it had no effect. And in other milkweed species, the presence of the fungi resulted in more disease for the caterpillars.”

The results also showed that the amount of the nutrient phosphorous associated with the fungi is important to the performance of the caterpillars. “It’s not just the drug dosage, but also the nutritional environment that determines the overall outcome,” Tao says.

“The interactions are really complex,” she adds. “It’s fascinating that even a species that is spatially distant, and from a different ecosystem, can have effects on how another species fights a disease.”

Monarch butterflies use drugs
Mystery of monarch migration takes new turn

Wednesday, October 7, 2015

The secret Maoist Chinese operation that conquered malaria — and won a Nobel

1964 poster: "Prevent Malaria and Take Care of People's Health." Painted by Wu Hao.

By Jia-Chen Fu, Assistant Professor of Chinese at Emory
For The Conversation

At the height of the Cultural Revolution, Project 523 – a covert operation launched by the Chinese government and headed by a young Chinese medical researcher by the name of Tu Youyou – discovered what has been the most powerful and effective antimalarial drug therapy to date.

Known in Chinese as qinghaosu and derived from the sweet wormwood (Artemisia annua L.), artemisinin was only one of several hundred substances Tu and her team of researchers culled from Chinese drugs and folk remedies and systematically tested in their search for a treatment to chloroquine-resistant malaria.

How Tu and her team discovered artemisinin tells us much about the continual Chinese effort to negotiate between traditional/modern and indigenous/foreign.

Indeed, contrary to popular assumptions that Maoist China was summarily against science and scientists, the Communist party-state needed the scientific elite for certain political and practical purposes.

Medicine, particularly when it also involved foreign relations, was one such area. In this case, it was the war in Vietnam and the scourge of malaria that led to the organization of Project 523.

North Vietnamese soldiers had to deal with disease as well as the enemy. (Photo via manhhai, CC.)

As fighting escalated between American and Vietnamese forces throughout the 1960s, malaria became the number one affliction compromising Vietnamese soldier health. The increasing number of chloroquine-resistant malaria cases in the civilian population further heightened North Vietnamese concern.

In 1964, the North Vietnamese government approached Chinese leader Mao Tse Tung and asked for Chinese assistance in combating malaria. Mao responded, “Solving your problem is the same as solving our own.”

From the beginning, Project 523, which was classified as a top-secret state mission, was under the direction of military authorities. Although civilian agencies were invited to collaborate in May 1967, military supervision highlighted the urgent nature of the research and protected it from adverse political winds.

The original three-year plan produced by the People’s Liberation Army Research Institute aimed to: "integrate far and near, integrate Chinese and Western medicines, take Chinese drugs as its priority, emphasize innovation, unify plans, divide labor to work together."

Project 523 had three goals: the identification of new drug treatments for fighting chloroquine-resistant malaria, the development of long-term preventative measures against chloroquine-resistant malaria, and the development of mosquito repellents. To achieve these ends, research on Chinese drugs and acupuncture was integral.

Read more in The Conversation.

Chestnut leaves yield extract that disarms deadly bacteria

Thursday, October 1, 2015

How close are we to living on Mars?

Matt Damon portrays an astronaut stranded on Mars in "The Martian." The movie opens this week, on the heels of NASA's discovery of liquid water on the Red Planet.

By Sidney Perkowitz, Emeritus Candler Professor of Physics at Emory

Like any long-distance relationship, our love affair with Mars has had its ups and downs. The planet’s red tint made it a distinctive – but ominous – nighttime presence to the ancients, who gazed at it with the naked eye. Later we got closer views through telescopes, but the planet still remained a mystery, ripe for speculation.

A century ago, the American astronomer Percival Lowell mistakenly interpreted Martian surface features as canals that intelligent beings had built to distribute water across a dry world. This was just one example in a long history of imagining life on Mars, from H G Wells portraying Martians as bloodthirsty invaders of Earth, to Edgar Rice Burroughs, Kim Stanley Robinson and others wondering how we could visit Mars and meet the Martians.

Drawing of Mars via NASA
The latest entry in this long tradition is the sci-fi flick The Martian, to be released on October 2. Directed by Ridley Scott and based on Andy Weir’s self-published novel, it tells the story of an astronaut (played by Matt Damon) stranded on Mars. Both book and movie try to be as true to the science as possible – and, in fact, the science and the fiction around missions to Mars are rapidly converging.

NASA’s Curiosity rover and other instruments have shown that Mars once had oceans of liquid water, a tantalizing hint that life was once present.

And now NASA has just reported the electrifying news that liquid water is flowing on Mars.

This discovery increases the odds that there is currently life on Mars – picture microbes, not little green men – while heightening interest in NASA’s proposal to send astronauts there by the 2030s as the next great exploration of space and alien life.

So how close are we to actually sending people to Mars and having them survive on an inhospitable planet? First we have to get there.

Making it to Mars won’t be easy. It’s the next planet out from the sun, but a daunting 140 million miles away from us, on average – far beyond the Earth’s moon, which, at nearly 250,000 miles away, is the only other celestial body human beings have set foot on.

Nevertheless, NASA and several private ventures believe that by further developing existing propulsion methods, they can send a manned spacecraft to Mars.

One NASA scenario would, over several years, pre-position supplies on the Martian moon Phobos, shipped there by unmanned spacecraft; land four astronauts on Phobos after an eight-month trip from Earth; and ferry them and their supplies down to Mars for a 10-month stay, before returning the astronauts to Earth.

We know less, though, about how a long voyage inside a cramped metal box would affect crew health and morale. Extended time in space under essentially zero gravity has adverse effects, including loss of bone density and muscle strength, which astronauts experienced after months aboard the International Space Station (ISS).

There are psychological factors, too. ISS astronauts in Earth orbit can see and communicate with their home planet, and could reach it in an escape craft, if necessary. For the isolated Mars team, home would be a distant dot in the sky; contact would be made difficult by the long time lag for radio signals. Even at the closest approach of Mars to the Earth, 36 million miles, nearly seven minutes would go by before anything said over a radio link could receive a response.

To cope with all this, the crew would have to be carefully screened and trained. NASA is now simulating the psychological and physiological effects of such a journey in an experiment that is isolating six people for a year within a small structure in Hawaii.

Engineers and technicians are already testing the spacesuit astronauts will wear in the Orion spacecraft on trips to deep space, including Mars. (NASA/Bill Stafford)

These concerns would continue during the astronauts' stay on Mars, which is a harsh world. With temperatures that average -80 Fahrenheit (-62 Celsius) and can drop to -100F (-73C) at night, it is cold beyond anything we encounter on Earth; its thin atmosphere, mostly carbon dioxide (CO₂), is unbreathable and supports huge dust storms; it is subject to ultraviolet radiation from the sun that may be harmful; and its size and mass give it a gravitational pull that is only 38% of the Earth’s – which astronauts exploring the surface in heavy protective suits would welcome, but could also further exacerbate bone and muscle problems.

As the astronauts establish their base, NASA is planning to use Mars' own resources to overcome some of these obstacles.

Fortunately, water and oxygen should be available. NASA had planned to try a form of mining to retrieve water existing just below the Martian surface, but the new finding of surface water may provide an easier solution for the astronauts. Mars also has considerable oxygen bound up in its atmospheric CO₂. In the MOXIE process (Mars Oxygen In situ resource utilization Experiment), electricity breaks up CO₂ molecules into carbon monoxide and breathable oxygen. NASA proposes to test this oxygen factory aboard a new Mars rover in 2020 and then scale it up for the manned mission.

There is also potential to produce the compound methane from Martian sources as rocket fuel for the return to Earth. The astronauts should be able to grow food, too, using techniques that recently allowed the ISS astronauts to taste the first lettuce grown in space.

Without utilizing some of Mars' raw materials, NASA would have to ship every scrap of what the astronauts would need: equipment, their habitation, food, water, oxygen and rocket fuel for the return trip. Every extra pound that has to be hauled up from Earth makes the project that much more difficult. “Living off the land” on Mars, though it might affect the local environment, would hugely improve the odds for success of the initial mission – and for eventual settlements there.

NASA will continue to learn about Mars and hone its planning over the next 15 years. Of course, there are formidable difficulties ahead; but it’s key that the effort does not require any major scientific breakthroughs, which, by their nature, are unpredictable. Instead, all the necessary elements depend on known science being applied via enhanced technology.

Yes, we’re closer to Mars than many may think. And a successful manned mission could be the signature human achievement of our century.

(This article first appeared in The Conversation.)