Thursday, December 17, 2015

Climate-smart agriculture still lags after Paris

Nitrous fertilizer usage in agriculture generates emissions of nitrous oxide one of the least-known, yet important, greenhouse gases.

Eri Saikawa, Emory assistant professor of Environmental Sciences, led a delegation of Emory students to the recent United Nations climate talks in Paris (COP21). An expert on greenhouse gas emissions, Saikawa wrote an opinion piece at the conclusion of the talks for The Conversation. Following is an excerpt of her article:

"Although the COP included initiatives targeting air pollution, climate and health all at once, there was a lack of comprehensive strategy for the interlinked effects of climate and agriculture at the summit.

"Agriculture contributes 10%-12% of global anthropogenic greenhouse gas (GHG) emissions, and it has altered all of the three important greenhouse gases linked to terrestrial sources: CO2, CH4 and nitrous oxide (N2O). The flip side is that there is a significant potential in agriculture for reducing these biogenic sources of greenhouse gases.

"The agricultural sector is also important because we need to pay more attention to nitrous oxide – possibly the least-known important GHG. N2O is not just a GHG; it also depletes the ozone layer in the stratosphere.

"The Montreal Protocol, which was ratified in 1989, has been effective at reducing greenhouse gases that are also ozone-depleting substances (Velders et al, 2006). However, N2O is not included in the Montreal Protocol, and its emissions are sharply rising.

"The concentrations of N2O in the atmosphere are increasing rapidly and we find that there is a statistically significant increase in emissions from the agricultural sector in Asia, including China and India. This makes sense, as the nitrogen fertilizer usage in these countries is the largest and the third-largest in the world and is only increasing."

Read the whole article in The Conversation.

The growing role of farming and nitrous oxide in climate change
Peachtree to Paris: Emory delegation headed to U.N. climate talks

Monday, December 14, 2015

Study shows how algal toxin damages sea lions' brains and behavior

Neuroscientist Peter Cook with one of the sea lions that served as a control during the study. (Photos courtesy of the Marine Mammal Center.)

By Carol Clark

A study of wild California sea lions provides the first neurobiological evidence for how a naturally occurring algal toxin affects both the brains and behavior of the animals, leading to significant deficits in spatial memory. The journal Science is publishing the findings, showing how domoic acid damages the sea lions’ hippocampus and disrupts an important neural network.

“We were able to correlate the extent of the hippocampal damage to specific behavioral impairments relevant to the animals’ survival in the wild,” says lead author Peter Cook, a post-doctoral fellow in the Center for Neuropolicy at Emory University. Cook conducted the sea lion research while a graduate student at the University of California, Santa Cruz, and he is continuing to expand on it at Emory.

“Our research provides a way to model the behavioral and biological effects of this toxin in a large-brain mammal,” Cook says. “Better understanding of these effects may also help us identify subtle effects in humans that may be at risk.”

Although cases of fatal human domoic acid poisoning are rare, due to careful monitoring of fisheries, it is unclear if there are effects that go undetected in communities that eat unmonitored seafood.

"Sea lions are like sentinels of ocean health," Cook says, "because when they are in distress, they will almost always swim to shore."

Warming oceans and agricultural runoff may be two factors contributing to an increase in harmful algae blooms, including the planktonic algae Pseudo-nitzschia. The algae produces domoic acid, a potent neurotoxin. During large blooms, the acid can become concentrated in the tissues of shellfish and in fish that feed on the algae. Sea birds and marine mammals that consume these marine organisms can then become poisoned.

Whales and dolphins are also likely impacted by domoic acid, Cook says, although they are more difficult to study than sea lions. “Sea lions are like sentinels of ocean health,” he says, “because when they are in distress, they will almost always swim to shore. We can measure their neurobiology in ways that we can’t in other animals that may also be in distress.”

Wildlife suffering from domoic acid toxicity can display a range of odd behaviors, including seizures, lethargy, disorientation, excessive friendliness or aggressiveness. The condition is often fatal.

Poisoned birds spawned a film.
In 1961, Monterey Bay summer resident Alfred Hitchcock was captivated by reports of frenzied sooty shearwaters. It was a mystery why flocks of the birds were seen regurgitating anchovies, flying into objects and dying in the streets. The incident inspired one of Hitchcock’s most famous films, “The Birds.”

Scientists did not connect domoic acid toxicity to strange behavior by wildlife in the region until the 1990s, when masses of brown pelicans became disoriented and died.

This year, the west coast experienced a massive algae bloom, the largest ever recorded. It extended from Southern California to Alaska, prompting numerous closures of shellfish fisheries.

Large algae blooms attract large schools of fish that feed on them, such as anchovies and sardines. That, in turn, attracts the sea lions. “They are opportunistic feeders and they like to gorge themselves when they have the chance,” Cook says.

Prior research has characterized some of the clinical effects of domoic acid poisoning, but Cook wanted to assess the behavioral effects in wild animals and measure the correlation between the biological changes.

During a three-year period, the research team studied 30 California sea lions undergoing veterinary care and rehabilitation at the Marine Mammal Center in Sausalito. The study included animals with and without symptoms of brain damage caused by exposure to domoic acid.

The sea lions underwent behavioral tests to assess their spatial memory and brain imaging (MRI). The results documented impaired performance on short- and long-term spatial memory tasks in animals with lesions on the right side of the hippocampus. The lesions appear similar to those seen in humans with medial temporal lobe epilepsy.

While acute poisoning can cause seizures and disorientation in sea lions, brain lesions develop over time, likely as a result of the chronic epileptic condition caused by one or more exposures to the toxin, Cook says. “We don’t know how heavy the exposure needs to be, or how often repeated, to cause this kind of brain damage, and we don’t know the effects of repeated low-dose exposure.”

The team also used functional MRI to look at the effects of domoic acid exposure on important brain networks. They found that sea lions with symptoms of toxic exposure had greatly reduced connectivity between the hippocampus and the thalamus, a pathway known to be essential for the formation of episodic memory – memories of events and experiences.

“This is the first evidence of changes to brain networks in exposed sea lions, and suggests that these animals may be suffering a broad disruption of memory, not just spatial memory deficits,” Cook says.

The sea lion study provides rare experimental evidence linking a naturally occurring neurotoxic effect to behavioral impairment in a wild animal. “Nature was doing the dosing. Our study was a natural experiment, giving it ecological validity,” Cook says. “Animals are complicated and they live in complicated environments that are changing really fast in ways that can have a negative impact on a wide range of species.”

Co-authors of the study also include researchers from the University of California, Davis, AnimalScan Advanced Veterinary Imaging, Pennington Biomedical Research Center; the Marine Mammal Center and the Shedd Aquarium. The work was funded by the National Science Foundation and the Lucile Packard Foundation.

A sea lion that bops to a musical beat

Thursday, December 3, 2015

Reporting from Paris: Student updates on COP21

Among the 10 undergraduates representing Emory at COP21 are, from left: Savannah Miller, Naomi Maisel, Taylor McNair, Mae Bowen and Siyue Zong.

“In a basement auditorium in a quiet Parisian neighborhood, writer Naomi Klein held an event to talk about the ‘Leap Manifesto: A Call for a Canada Based on Caring for the Earth and One Another,’” reports Emory junior Clara Perez from the scene.

“Climate change, Klein said, is the catalyst to transformative change in all kinds of struggles – indigenous, class, anti-racism, among many others. She called for addressing climate change in a way that is ‘based on justice and redressing historical wrongs.’”

Now midway through a two-week trip to Paris, a delegation of Emory undergraduates are providing real-time updates on the 21st Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP21) and related events.

On the web site they’ve created, the students have posted photos of a demonstration that happened shortly after they landed in Paris. And they are gathering “snapshot” bios of other attendees, under the heading “Humans of COP21.”

Senior Taylor McNair writes: “From a business perspective, carbon pricing at COP21 is arguably the most exciting news to emerge from the first few days of the conference.”

Senior Mae Bowen was intrigued by an event at the Kedge Business School in Paris. Jean-Christophe Carteron presented a Sustainability Literacy Test he developed as a tool for universities and corporations to assess and develop the knowledge of their community members.

“While ‘sustainability’ is still a complicated term,” Bowen writes, “the goals of the Sustainability Literacy Test are admirable and a step in the right direction. No business or government leader should be able to claim ignorance when making decisions that negatively affect the future of our planet and humanity.”

Watch the web site for daily updates and follow the students’ updates on Twitter: @EmoryinParis.

And check out the podcasts that the students created as part of the Emory course “Paris is an Explanation: Understanding Climate Change at the 2015 United Nations Meeting in France.”

Peachtree to Paris: Emory delegation headed to U.N. climate talks

Tuesday, December 1, 2015

Nano-walkers take speedy leap forward with first rolling DNA-based motor

"Ours is the first rolling DNA motor, making it far faster and more robust," says Khalid Salaita, the Emory chemist who led the research. (Photos by Bryan Meltz, Emory Photo/Video.)

By Carol Clark

Physical chemists have devised a rolling DNA-based motor that’s 1,000 times faster than any other synthetic DNA motor, giving it potential for real-world applications, such as disease diagnostics. Nature Nanotechnology is publishing the finding.

“Unlike other synthetic DNA-based motors, which use legs to ‘walk’ like tiny robots, ours is the first rolling DNA motor, making it far faster and more robust,” says Khalid Salaita, the Emory University chemist who led the research. “It’s like the biological equivalent of the invention of the wheel for the field of DNA machines.”

The speed of the new DNA-based motor, which is powered by ribonuclease H, means a simple smart phone microscope can capture its motion through video. The researchers have filed an invention disclosure patent for the concept of using the particle motion of their rolling molecular motor as a sensor for everything from a single DNA mutation in a biological sample to heavy metals in water.

“Our method offers a way of doing low-cost, low-tech diagnostics in settings with limited resources,” Salaita says.

The field of synthetic DNA-based motors, also known as nano-walkers, is about 15 years old. Researchers are striving to duplicate the action of nature’s nano-walkers. Myosin, for example, are tiny biological mechanisms that “walk” on filaments to carry nutrients throughout the human body.

“It’s the ultimate in science fiction,” Salaita says of the quest to create tiny robots, or nano-bots, that could be programmed to do your bidding. “People have dreamed of sending in nano-bots to deliver drugs or to repair problems in the human body.”

So far, however, mankind’s efforts have fallen far short of nature’s myosin, which speeds effortlessly about its biological errands. “The ability of myosin to convert chemical energy into mechanical energy is astounding,” Salaita says. “They are the most efficient motors we know of today.”

Some synthetic nano-walkers move on two legs. They are essentially enzymes made of DNA, powered by the catalyst RNA. These nano-walkers tend to be extremely unstable, due to the high levels of Brownian motion at the nano-scale. Other versions with four, and even six, legs have proved more stable, but much slower. In fact, their pace is glacial: A four-legged DNA-based motor would need about 20 years to move one centimeter.

Kevin Yehl, a post-doctoral fellow in the Salaita lab, had the idea of constructing a DNA-based motor using a micron-sized glass sphere. Hundreds of DNA strands, or “legs,” are allowed to bind to the sphere. These DNA legs are placed on a glass slide coated with the reactant: RNA.

The DNA legs are drawn to the RNA, but as soon as they set foot on it they destroy it through the activity of an enzyme called RNase H. As the legs bind and then release from the substrate, they guide the sphere along, allowing more of the DNA legs to keep binding and pulling.

“It’s called a burnt-bridge mechanism,” Salaita explains. “Wherever the DNA legs step, they trample and destroy the reactant. They have to keep moving and step where they haven’t stepped in order to find more reactant.”

The combination of the rolling motion, and the speed of the RNase H enzyme on a substrate, gives the new DNA motor its stability and speed.

“Our DNA-based motor can travel one centimeter in seven days, instead of 20 years, making it 1,000 times faster than the older versions,” Salaita says. “In fact, nature’s myosin motors are only 10 times faster than ours, and it took them billions of years to evolve.”

Emory post-doctoral fellow Kevin Yehl sets up a smart-phone microscope to get a readout for the particle motion of the rolling DNA-based motor.

The researchers demonstrated that their rolling motors can be used to detect a single DNA mutation by measuring particle displacement. They simply glued lenses from two inexpensive laser pointers to the camera of a smart phone to turn the phone into a microscope and capture videos of the particle motion.

“Using a smart phone, we can get a readout for anything that’s interfering with the enzyme-substrate reaction, because that will change the speed of the particle,” Salaita says. “For instance, we can detect a single mutation in a DNA strand.”

This simple, low-tech method could come in handy for doing diagnostic sensing of biological samples in the field, or anywhere with limited resources.

The proof that the motors roll came by accident, Salaita adds. During their experiments, two of the glass spheres occasionally became stuck together, or dimerized. Instead of making a wandering trail, they left a pair of straight, parallel tracks across the substrate, like a lawn mower cutting grass. “It’s the first example of a synthetic molecular motor that goes in a straight line without a track or a magnetic field to guide it,” Salaita says.

In addition to Salaita and Yehl, the co-authors on the Nature Nanotechnology paper include Emory researchers Skanda Vivek, Yang Liu, Yun Zhang, Megzhen Fan, Eric Weeks and Andrew Mugler (who is now at Purdue University).

Chemists reveal the force within you
Molecular beacons shine light on how cells 'crawl'

Wednesday, November 18, 2015

Babies have logical reasoning before age one, study finds

Deductive problem solving was previously thought to be beyond the reach of babies, says Emory psychologist Stella Lourenco.

By Carol Clark

Human infants are capable of deductive problem solving as early as 10 months of age, a new study finds. The journal Developmental Science is publishing the research, showing that babies can make transitive inferences about a social hierarchy of dominance.

“We found that within the first year of life, children can engage in this type of logical reasoning, which was previously thought to be beyond their reach until the age of about four or five years,” says Stella Lourenco, the Emory University psychologist who led the study.

The researchers designed a non-verbal experiment using puppet characters. The experiment created scenarios among the puppets to test transitive inference, or the ability to deduce which character should dominate another character, even when the babies had not seen the two characters directly interact with one another. A majority of the babies in the experiment, who were ages 10 to 13 months, showed a pattern consistent with transitive inference.

“Everybody knows that babies learn rapidly, like little sponges that soak in incredible amounts of knowledge,” Lourenco says. “This finding tells us about how humans learn. If you can reason deductively, you can make generalizations without having to experience the world directly. This ability could be a crucial tool for making sense of the social relationships around us, and perhaps complex non-social interactions.”

During the 1960s, developmental psychologist Jean Piaget showed that children could solve transitive inference problems around the age of seven or eight. For example, if you know that Paul is taller than Mary, and that Mary is taller than Jack, then you can infer indirectly that Paul must be taller than Jack. You don’t need to see Paul and Jack standing side-by-side to draw this conclusion.

For years, the prevailing philosophy in cognitive psychology was that children younger than seven were mostly illogical and incapable of transitive inference. Then, during the late 1970s, researchers found that by reducing the complexity of transitive inference problems, children as young as four could solve them.

Lourenco, whose research has shown that babies have numerical reasoning and can understand relationships of magnitude, suspected that infants were also capable of transitive inference.

A screen shot of a video from one of the experiments shows a subject watching the puppets interact.

For the current study, Lourenco teamed up with co-authors Robert Hampton, an Emory psychologist whose lab at Yerkes National Primate Research Center has demonstrated that monkeys can engage in transitive inference, and Regina Paxton Gazes, a former graduate student in the Hampton lab and post-doctoral fellow at Zoo Atlanta. Gazes, who is now on the psychology faculty at Bucknell University, designed the non-verbal experiments for the human infants.

In the first experiment, the babies were shown a video of three puppets arranged in a row. The puppets – an elephant, a bear and a hippopotamus, were similar in size but arranged in a left to right social hierarchy. The elephant is holding a toy, but the bear reaches over and forcibly takes the toy from the elephant. Next, the hippopotamus takes the toy from the bear. These scenarios suggested that the bear is more dominant than the elephant, and the hippo is more dominant than the bear.

Finally, the babies were shown a scenario where the elephant takes the toy from the hippo. This scenario held the gaze of most the babies in the experiment for longer than the other scenarios.

“Dominance by the elephant violates the expected transitive-inference relationship, since the bear took the toy from the elephant and the hippo took the toy from the bear,” Lourenco explains. “The babies look longer and pay greater attention to the scenario that violates the transitive inference as they try to figure out why it is different from what they would have predicted.”

In a second experiment, the researchers introduced a fourth character, a giraffe, that had not yet interacted with the others in the familiarization phase. The giraffe was novel and had not previously displayed dominance behavior. The infants did not pay more attention to scenarios involving the giraffe, whether or not it displayed dominance.

The researchers also conducted control experiments with infants. For the controls, the hippo always displayed dominant behavior and the elephant always displayed subordinate behavior.

The data supported that the majority of the infants who were shown unexpected dominance behaviors, or 23 out of 32, were engaging in transitive inference when they gazed at scenarios of unexpected behavior by the puppets, compared to other scenarios. The researchers hypothesize that transitive inference for social dominance is evolutionarily important, so the mechanisms to support this type of logical reasoning are in place early.

“It’s remarkable that the infants could make these inferences about social dominance with minimal presentation,” Gazes says. “It suggests an early emerging, and perhaps evolutionary ancient ability, that is shared with other animals.”

In addition to exploring important science questions about how the mind develops, the findings could aid in determining whether infants are on track in the learning process. “Since a majority of babies show the ability to engage in this kind of logical problem solving, our paradigm could certainly become an important tool for assessing normative cognitive development,” Lourenco says.

How babies use numbers space and time

Top image: Thinkstockphoto

Wednesday, November 11, 2015

Peachtree to Paris: Emory delegation headed to U.N. climate talks

On a recent Saturday, 30 students represented a country, or block of countries, to simulate the U.N. talks. Naomi Maisel, right, made the case for India. "You have to rethink your reality based on all the countries involved and figure out how to make it work," she says. (

By Carol Clark

More than 40,000 people from around the world are expected to descend on Paris, France, from November 30 to December 11, for what many see as the best chance yet for a universal climate agreement. The goal of the 21st Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP21) is to keep global warming to no more than 2 degrees Celsius since the start of the Industrial Revolution.

Everyone from President Obama to Atlanta Mayor Kasim Reed will be on the ground in Paris for high-stakes conversations about the fate of the planet. Ten Emory undergraduates and two faculty are also joining the historic event with the status of official U.N. observers.

“This is an unprecedented time,” says Taylor McNair, a senior majoring in environmental sciences and business. “People are coming into this conference with a mindset they have never had before. I’m optimistic that there will be some progress coming out of Paris, and that we will see some serious change during the next few years.”

McNair and three other Emory students will actually spend part of COP21 inside the main hall where delegates from 195 countries will negotiate reductions of their greenhouse gas emissions. And all 10 of the students will be gathering information from the milieu of related conferences, demonstrations, exhibits and informal discussions that will be humming around the main COP21 meeting.

The students will post photos and dispatches on a special web site they are creating for the event (, through the Emory Writing Program's Domain of One's Own. And they will use social media to further connect Emory and the Atlanta community to what’s happening in Paris, as it happens. You can follow their conversations on their Twitter handle @EmoryinParis, and via their hash tag: #PeachtreeToParis. Senior Tyler Stern is helping develop the team's social media platforms, which also include Instagram (EmoryParis15) and Snapchat (EmoryInParis).

After four hours of tense negotiations, students participating in simulated U.N. talks were only able to achieve caps on greenhouse gas emissions for a temperature rise of 3.5 degrees Celsius, short of the 2 degrees goal. 

“Climate change is not an issue that is coming in 100 years. It’s happening now,” says Naomi Maisel, a junior majoring in anthropology who will be making the trip. “We want to convey the sentiments of the people that we meet and give Emory students a sense of how the rest of the world is thinking about and dealing with climate change."

The students plan to also bring back lessons for what everyone can do to get involved. They will help organize an Emory “Climate Week” and a series of COP21 related events on campus in the Spring – including art exhibits, panel discussions and special lectures – in conjunction with the Climate@Emory initiative.

Debating the fate of the planet.
“I’m optimistic that some kind of meaningful deal will be reached in Paris,” says Mae Bowen, a senior majoring in environmental sciences and political science, who is headed for COP21. “But once a deal is made, that’s when the real work starts, making that deal come to fruition.”

The Paris trip is the capstone to a Coalition of the Liberal Arts (CoLA) course, aimed at integrating the liberal arts experience across the humanities and sciences. The course, “Paris is an Explanation: Understanding Climate Change at the 2015 United Nations Meeting in France,” was developed and taught by three faculty: Wesley Longhofer, an expert in organization and management at Goizueta Business School; Eri Saikawa, an expert in climate science in the department of environmental sciences and Rollins School of Public Health; and Sheila Tefft, senior lecturer in the Emory Writing Program. Bowen and another undergraduate, Adam Goldstein, also helped develop the course.

Both Longhofer and Saikawa will accompany the students on the trip to Paris.

Throughout the fall, the students are exploring climate change from environmental, business, media and political perspectives. Saikawa led discussions about the complex atmospheric science surrounding emissions. Longhofer organized mock UN negotiations so that the students could better understand perspectives of the various countries involved. Tefft focused on issues of communications and trained the students in journalistic techniques and technology, including podcasting and social media.

The Emory students have a range of research interests that they plan to hone in on as COP21 is underway. Below are brief bios, and a guide to their plans for Paris.
Taylor McNair

BUSINESS: Taylor McNair is a senior from West Port, Connecticut, majoring in business and environmental sciences. “I have a big interest in renewable energy,” he says. “I’ve had some work experience in that field and it’s helped shape what I think will be the defining challenge of the future: How will we switch from cheap fossil fuels and power our lives and economies with renewable energy?”

He notes that major companies like Google and Facebook have already announced they will be moving toward renewable energy sources for their datasets.

“We need more market-based solutions for addressing climate change,” he says. “It’s beginning to make economic sense to make investments in energy efficiency and renewable fuel sources. I think more people are waking up to the fact that this transition can not only be beneficial from an environmental and health aspect, but also from a financial aspect.”

POLICYMAKING: Mae Bowen is a senior majoring in environmental sciences and political science. Bowen, who is from Panama City, Florida, personally experienced the social and ecological impacts of hurricanes and the BP oil spill in the Gulf of Mexico. Even after the beaches near her home were cleaned and declared safe following the spill, tourists did not return for years due to public perceptions and media coverage.
Mae Bowen

“I was fascinated and frustrated by that,” Bowen says. “I’ve been thinking about the best ways to communicate environmental issues ever since.”

Bowen’s other passion is policymaking. She is a member of the Emory International Relations Association – a team of students that travels to universities across the country to participate in simulations of U.N. negotiations, based on real-world situations and research. While these exercises help Bowen see the challenges of policymaking, they have not made her cynical. “The fact that we have people from different countries and cultures coming together to try and solve a global problem like climate change – that’s kind of awesome,” she says. “I’m just so excited to go to COP21 and get to hear the actual deliberations over the issue I care most about.”

The Paris talks may not achieve the goal of reducing emissions to reach the goal of 2 degrees, “but it’s going to take us forward,” Bowen says. “I’m a big picture person. I would rather have a deal that goes part of the way than to have nothing at all. You have to take things one step at a time.”

Savannah Miller
EMORY AND ATLANTA: Savannah Miller, a senior majoring in environmental sciences and creative writing is focused on climate change adaptation and mitigation efforts at the local level. She is currently an intern for the city of Atlanta, working with the team developing a major climate action plan. “Emory was an early supporter of the Atlanta Better Buildings Challenge,” Miller says. “The university has been a leader in sustainability for years and our efforts keep gaining momentum.”

While at the Paris talks, she will be researching how other communities from around the world are implementing adaptive technologies and strategies for increasing energy efficiency. “One of our biggest goals is to bring back information about environmental policies and communicate them in a way that reaches our generation,” Miller says.

In addition to contributing to the Emory group web site for COP21, Miller has developed her own site,, for communicating environmental issues. Her first post looked at the connections between climate change and recent historic flooding in her hometown of Charleston, South Carolina.
Naomi Maisel

AGRICULTURE: Naomi Maisel, a junior majoring in anthropology, is researching the impact of climate change on agriculture and food security. “Farmers are starting to see effects faster and more intensely, especially in the developing world,” Maiesel says. “We don’t know if a lot of food systems can withstand more or less rainfall, more or less heat, and higher concentrations of carbon dioxide.”

Maisel contacted a farmer outside of Paris who has agreed to give the students a tour of his farm and explain his experience of climate change.

While growing up in San Diego, Maisel recalls that many discussions about climate change were debates about whether it was happening. “Now, most of the conversations I’m hearing revolve around questions like, how bad is it going to be and what are we doing about it,” she says. “People are finally starting to take it seriously. And they realize that it is not just a science problem. It’s an economic issue, a security issue and a public health issue. Everybody is going to be affected, so everybody needs to be involved.”

Clara Perez, a junior majoring in sociology and sustainability, is focused on how climate change will disproportionately impact lower socio-economic groups.

Caiwei Huang (a junior majoring in interdisciplinary studies and political science) and Siyue Zong (a senior environmental sciences major) both want to follow the crucial negotiations of the two biggest greenhouse gas emitters: The United States and China. (Huang is developing a web site to introduce students to the fundamentals of Chinese politics:

Samuel Budnyk, a junior majoring in comparative literature and music, is especially interested in communicating to the general public and hopes to write a post a day for the Emory Wheel during the talks.

Adam Goldstein and Mark Leone (both seniors majoring in business) will be focused on gathering information about climate finance – the move toward investing in low-carbon and more resilient economies.

Tuesday, November 3, 2015

Lionfish study explores idea of eating an ecological problem

"Some areas where lionfish have taken over reefs show a marked decrease in biodiversity," says Emory fisheries expert Tracy Yandle.

By Carol Clark

The lionfish is a ferocious ocean carnivore with a flamboyant “mane” of venomous spines. This exotic maroon-and-white creature, native to the Indo-Pacific, made its way west through the aquarium trade. During recent years, however, wild lionfish became established in the Gulf of Mexico, the Caribbean Sea and the Atlantic. Releases of lionfish and their eggs from aquariums have been blamed for this invasion.

While the long-term impact of the lionfish is unknown, fisheries experts are worried. The lionfish, from the Pterois genus of venomous marine fish, reproduces rapidly and has few natural enemies outside of the Indo-Pacific to keep its population in check. Meanwhile, lionfish are devouring small crustaceans and the young of commercial fish species like snapper and grouper, according to the National Marine Fisheries Service (NMFS).

“Some areas where lionfish have taken over reefs show a marked decrease in bio-diversity,” says Tracy Yandle, an associate professor in Emory’s Department of Environmental Sciences. Yandle studies issues around the regulation of the fishing industry and the governance of natural resources.

Luckily, the invasive lionfish is not just ecologically “evil.” It is also tasty. Many describe lionfish meat as a mildly flavored, nicely textured white fish, similar to snapper.

Yandle recently received a $300,000 grant from the NMFS to research the opportunities and challenges of creating a market for lionfish as food in the U.S. Virgin Islands, one area where the invader is proliferating. Co-investigators on the grant include Emory post-doctoral associate Jennifer Tookes, Emory environmental sciences lecturer Michael Page and Sherry Larkin from the University of Florida.

About 30 percent of people in the USVI live below the poverty line and food can be expensive in the islands. The fishing industry is also a traditional part of the USVI’s economy, as well as its cultural heritage, so finding ways to control the lionfish population is especially critical.

“The traditional goal of fisheries regulation is to try to avoid overfishing and to preserve a species,” Yandle says. “In the case of the lionfish in the USVI, the lionfish is invasive, so the concept of over-fishing doesn’t really apply.”

Some people in the Caribbean have already acquired a taste for lionfish and are experimenting with ways to prepare the invader. Photo by Scott Crosson.

As part of the project, Emory undergraduates will spend classroom time next spring learning about fisheries management, research methods and the culture of the USVI. They will then travel to the islands to work in the field.

The students will survey seafood consumers at local markets. and the tourists who often patronize restaurants, to help access the social and economic viability of the lionfish as a food fish. A graduate student from the Masters in Development Practice program will spend a summer practicum in the USVI coordinating efforts between this research project and The Nature Conservancy’s reef preservation efforts.

“Lots of great natural science work has already been done on lionfish,” Yandle says. “This is a human project. We want to talk with the local people and understand how they think about lionfish and whether they are interested in fishing and eating them.”

Lionfish have already started popping up as an “eco-chic” option on a few select U.S. coastal restaurant menus, from Miami to Maine, and in parts of the Caribbean.

“There’s the sustainability factor,” Michael Schwartz of Michael’s Genuine Food and Drink in Miami, told Garden and Gun Magazine, “but also just that the meat tastes good. We make a great lionfish sandwich.”

So what’s the catch?

Lionfish, which grow to about 15 inches, are rarely reeled in by hook and line. They are most often taken by more labor-intensive methods, such as a spear or a hand-held net, or as bycatch in trap fisheries.

Then, there are the long, venomous spines jutting out from every lionfish. Special care must be taken during their handling because these spines can cause painful injuries.

The good news is that the flesh of a lionfish is not poisonous.

The bad news: It does not have much flesh compared to other species like grouper. “Lionfish are bony and the yield rate is about 30 percent, which is less meat than some species,” Yandle says. 

The project will analyze whether there are viable ways to deal with these challenges in the local context of the USVI and create a new market for sustainable seafood.

In addition to consumers, the research team will also survey local fishermen. The fishermen will be asked their knowledge of where lionfish are most prevalent in the local waters, and whether those areas overlap with sites known for ciguatera. Ciguatera is a naturally occurring toxin found in Caribbean waters that can accumulate in coral, algae and seaweed, contaminating fish stocks and leading to food-borne illness.

Page, an expert in geo-spatial analysis, will combine the information from the surveys of the fishermen with previous data gathered by scientists to create maps of the safest and best places to harvest lionfish. The local fishermen will be given books of these maps, as well as a kit with tools to assist fishing for lionfish, at the end of the project.

The findings of the study will be shared in local meetings and added to the online lionfish portal of the Gulf and Caribbean Research Institute, so that the public may benefit.

“At the end of the project, we will figure out if there can be a viable market for the lionfish, and if so, we will provide guidance for how the market could be developed,” Yandle says.

The case of the golden crabs: Cracking mysteries of how fishermen stay afloat
Fishing for a living comes with a catch

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.)

Monday, September 28, 2015

Chemistry Center ignites celebration of science

“Why do I have a garbage can full of liquid nitrogen? Because I’m a chemist,” Doug Mulford, director of undergraduate education for Emory’s Department of Chemistry, told a crowd of enthralled children and adults.

Decked out in safety glasses and a red lab coat printed with flames, Mulford conducted a ribbon immolation ceremony on Saturday, to officially open Emory’s Sanford S. Atwood Chemistry Center addition. The crowd gasped and cheered in the courtyard as Mulford ignited a thermite reaction, a pyrotechnic mixture of aluminum and iron oxide. The reaction shot off sparks and smoking-hot globules of molten iron to sever the ceremonial ribbon.

Rain did not dampen anyone’s enthusiasm for the grand opening, which included fun science demonstrations by students from chemistry, biology and physics.

In fact, chemists love water droplets and clouds. Graduate students from Emory’s Pi Alpha Chemical Society showed how to make both, using liquid nitrogen.

“We’re pouring really hot water into really cold liquid nitrogen, causing it to expand into a plume of air that comes up as a cloud,” explained Daniel Collins-Wildman, who braved nature’s drizzle in the courtyard along with fellow graduate student Amanda Dermer.

In fact, Collins-Wildman said, the liquid nitrogen is so cold (77 Kelvin) that ice particles form in the cloud, creating what is known as a nucleation site where water drops can form.

“I conducted an experiment with this by accident once, when I was making macaroni and cheese,” he said. He brought the water to a roiling boil. As usual, bubbles formed along the sides of the pot, where the temperature is higher and the pot’s irregular surface creates the potential for nucleation. Then the power went out. The bubbles on the sides of the pot disappeared. The water was still hot when he turned the heat back on. Without the small bubbles acting as nucleation sites the water boiled violently, a phenomenon known in chemistry as "bumping."

"I heard this weird sound," Collins-Wildman said. "All those little bubbles that had formed slowly before, this time formed immediately as one huge bubble that came to the surface with a BLURP!”

Chemistry Center turns up the heat for grand opening

Monday, September 21, 2015

Leaping molecules! How a frog evolved violet vision

The story of the evolution of color vision in the African clawed frog, above, "is full of mysterious twists and turns," says evolutionary biologist Shozo Yokoyama. Photo by Brian Gratwicke.

By Carol Clark

The African clawed frog is tongue-less, has long, curvy toes and eyes that are perched on top of its head, but that’s not all that’s odd about it. This species of frog also took a strange evolutionary path to change from ultraviolet to violet vision: Some of its visual pigment molecules kept trying to leap ahead, but other molecules shut them down and kept the process moving at a crawl. 

Science Advances published the complete molecular interactions involved in the pathway, as detailed in a study led by Shozo Yokoyama, a biologist at Emory University who specializes in adaptive evolution of vision.

“It’s the most bizarre, and sophisticated, case of color vision evolution that I’ve ever encountered,” says Yokoyama, who previously headed up efforts to construct the most extensive evolutionary tree for vision, including 500 species of animals, from eels to humans.

“This frog had these quirks for rapid molecular change, but it also had something to control these quirks,” he says. “In fact, it had triple protection.”

Five classes of opsin genes encode visual pigments for dim-light and color vision. Bits and pieces of the opsin genes change and vision adapts as the environment of a species changes.

Ultraviolet (UV) vision gives a bi-chromatic, high-contrast view of the world that can be useful for many basic behaviors. Mice, for instance, are mainly nocturnal and mark their territory with urine and feces that reflects UV light for other mice. Unfortunately for mice, however, many of their predators are also UV sensitive so they, too, can spot these signs of mice more easily.

Violet vision, or the ability to see blue light, provides better resolution and detail for colors in a scene. Among the possible reasons that frogs evolved from UV to violet sensitivity may have been to give them a better view of potential mates. It may also have improved their ability to pick out predators – such as a green snake amid green leaves.

In other recent research, Shozo Yokoyama, above, finished the first detailed and complete picture of the evolution of human vision. Photo by Bryan Meltz, Emory Photo/Video.

In previous research on the African clawed frog (Xenopus laevis), Yokoyama and collaborators had identified some of the genetic mutations involved in the process of the frog’s switch from UV vision to its current function of violet vision. They also noticed that amino acid site 113 on this pigment of the African clawed frog had changed from glutamic acid to aspartic acid.

“Out of all the species in the animal kingdom that have been studied, site 113 is made up of glutamic acid, but this frog had changed site 113 to aspartic acid,” Yokoyama says. “Why did it do that? This question was very mysterious and interesting to me. What is so special about this frog?”

Yokoyama studies ancestral molecules to tease out secrets of adaptive evolution. The lengthy process involves teams of collaborators to first estimate and synthesize ancestral proteins and pigments of a species, then conduct experiments on them. The technique combines microbiology with theoretical computation, biophysics, quantum chemistry and genetic engineering.

For the current paper, he and his co-authors found that 12 mutations were involved in the frog’s vision shift. These 12 molecular changes could have 500 million possible combinations of pathways that connect the ancestral UV vision and the frog’s violet vision. The researchers narrowed the problem down and focused on changes in the six layers of transmembranes where the 12 molecules in the process are located. That focus reduced the number of possible evolutionary pathways to 720.

They then assembled molecular “chimeras” between the ancestral and frog pigments for all of these pathways. They tested how the molecules functioned in all the different combinations, to hone in on the right pathway.

The results showed that the mutations that occurred on transmembranes four, five and six happened early during the evolutionary process. It was not until eons later, however, that these mutations came into play.

The mutations occurring on transmembrane two caused small shifts in the range of the light spectrum that the pigment detected. The mutations occurring early in evolution on transmembrane three, however, where site 113 resides, caused a big jump in the light-wave range – from 400 nanometers to 600 nanometers. 

“Rapid change is not convenient evolutionarily,” Yokoyama says. “In fact, it can be a disaster.” 

He uses the example of emerging from a darkened movie theater on a sunny day, and being temporarily blinded until your eyes adjust to the new environment.

Three times, molecules on transmembrane three mutated to cause a big jump toward violet sensitivity. The first time it happened, transmembrane five came into play, shrinking the molecular structure of the pigment and making it non-functional.

The second time that transmembrane three mutated, launching another jump, transmembrane six sprang into action, again shrinking the molecular structure.

The third time transmembrane three tried to make the evolutionary leap, number four shut it down by destroying a critical chemical structure of the pigment.

The frog pigment essentially put on the brakes early during the evolutionary process for the mutations from glutamic acid to aspartic acid at site 113. Only towards the end of the process did the pigment accept the site 113 shifts. By then, Yokoyama explains, the changes to the frog’s light spectrum were no longer a big jump. Instead, they were just 15 nanometers.

“The human process for evolving from UV to violet vision was far more simple and straight-forward,” Yokoyama says. “The story of this frog is full of mysterious twists and turns. A series of strange coincidences happened at the right time, at the right spot, for the right species.”

Yokoyama’s co-authors for the current paper include Emory biologists Huiyong Jia, Takashi Koyama, Davide Faggionato and Yang Liu; and Ahmet Altun of Faith University in Istanbul and William Starmer of Syracuse University.

A clear, molecular view of the evolution of human color vision