January 11, 2019

By Mallory Rosten, Communications Assistant

If you wander behind West Village, the dining hall that doubles as a community center on West campus, you’ll find twin residence halls Folk and Caldwell. They look the same as other dorms on quiet West campus, but looks can be deceiving.

Inside lives a buzzing community of young scientists and mathematicians, bonded together by curiosity and chemistry labs. In the basement, students would excitedly work together to solve a problem on the white board walls, late at night before a test. In the lounges, students might vigorously debate whether a hot dog is a sandwich, citing scientific sources and data.

These students are part of the College of Sciences’ Living Learning Community, or LLC. Formerly two separate LLCs, SHaRP (Science Health and Related Professions) and SMaRT (Science and Math Research Training), the program is now known as Explore. The staff found that the two LLCS often overlapped: pre-health students were interested in research, research students were interested in pre-health, and the students spent so much time together that there was no need for division.

By housing science and math majors together in their first year of college, Explore hopes to foster a community and create an identity around science and mathematics.

Jennifer Leavey, Explore’s faculty director, was a Tech undergrad herself. “I had no idea there even was a College of Sciences,” she says. “For such a long time the campus was so dominated by engineers, there wasn’t much of an identity for science and math majors.” Explore, she says, is for “the kids who are curious, the kids who like to wear NASA T-shirts.”

Explore hosts 280 students who want more from dorm life than the usual first-year experience. By joining Explore, science- and math-oriented students can live together, take classes together, and distract themselves from their studies together. It’s also a place of discovery where students can find the field that fits them best, which is why the new name is particularly apt.

 “To think that a 16- or 17-year-old is going to stick with the major they chose when they applied is unrealistic and a little stifling,” says Emma Blandford, Explore’s assistant director. “To see them step back a little bit and see the other things out there and explore other opportunities is a breath of fresh air.”

A Place of Discovery
When Hudson Moss began his freshman year, he was sure that he wanted to major in biochemistry. But when Moss watched Kim Cobb give a talk on her 2016 expedition to Holiday Island, he knew immediately that he wanted to work with her.

Cobb is a professor in the School of Earth and Atmospheric Sciences. “It was really cool, the way that she talked about paleoclimate and how we can approach climate changes as a community and as a country,” Moss says. His chance came when he had to interview a professor for his SMaRT GT 1000 class. He knew exactly whom to choose.

“I managed to slip in that I wanted to work for her at some point,” Moss says, and that first meeting ignited a research path that continues today. He started attending Cobb’s lab meetings.  By the end of his second semester, Moss had started working in Cobb’s lab and officially switched his major to Earth and atmospheric sciences. He still works there today and is on his way to becoming the first author of a study mapping the 19th-century climate of the equatorial Pacific.

“That initial bump that SMaRT gave me to go interview a professor, to get out there and talk to faculty – that was huge,” Moss says. It forced him to be comfortable talking to an expert like Cobb. Now, he says, he can strike a conversation with any faculty member.

Living, Learning, and Thriving
In addition to offering LLC-specific first-year seminar classes for their students, the LLC reserves chemistry labs and even English sections so that their students are connected with the community throughout the day.

When they come home from class, the students organize stress relief activities, like cookie and milk breaks and Halloween parties. Recently, 30 students went to the Centers for Disease Control and Prevention to learn about the refugee crisis through the lens of public health.

At the start of every school year, the students go on a retreat where they climb ropes, solve escape rooms, and attend panels for advice about undergraduate research.

“They can go out and go to class and do work and they can come home – it’s their own little oasis,” Blandford says, “My hope is that the community they’re developing here is not isolating them from the rest of Tech, but helping them to feel supported to go out and try new things.”

Because Moss is now a second-year student, he is no longer officially part of the LLC, but he still goes back to give talks to the students, helping them figure out their own paths. 

Alumni can also work as student assistants in the program, helping to coordinate activities, and as team leaders.

The biggest indicator of the program’s success, Blandford says, is the fact that 50% of students signed up to continue living with “smarties and sharpies” in the Eighth Street apartments across the street from Folk and Caldwell.

“They liked each other enough that they wanted to stay in this community again for another year,” Blandford says. She sees this preference as a sign that these students truly feel supported by one another.

All Together Now
“I didn’t expect everyone to come together as quickly as they did,” Bryan Gomez, a biochemistry and neuroscience major in what was formerly SHaRP, admits. “The first couple weeks, everyone was still getting to know each other, but once classes hit the ground and midterm week hit, it was like we’re all in this together.”

Gomez is still in his first year, but he started as a summer freshman. Now he works as a marketing student assistant for Explore.

He credits the LLC for the ease of his transition to college life. “They provide resources to get help when I’ve needed it and when everyone else has needed it,” he says.

Leavey wishes Explore were around when she was a Tech undergrad. “My son wants to be in the program when he goes to college,” Leavey says, laughing.

January 8, 2019

By Laura Mast, Contributing Writer

A unique treat awaits fans at the Yellow Jackets’ Jan. 22 men’s basketball home game. The Georgia Tech team will battle Notre Dame’s Fighting Irish for the hoops amid element cards, games, and prizes to celebrate 2019, the International Year of the Periodic Table of the Chemical Elements.  

Born 150 years ago, the periodic table is one of the most important and recognizable tools of science. To celebrate the table’s staying power, the United Nations proclaimed 2019 as the International Year of the Periodic Table of Chemical Elements.

At Georgia Tech, the College of Sciences is leading an all-year-round celebration, #IYPT2019GT. It has partnered with other units to engage students, faculty, and staff in reconnecting with the periodic table, through athletics, art, and academics.

Kicking off the celebration is “The Periodic Table at Georgia Tech vs Notre Dame” men’s basketball match on Jan. 22. Partnering with Georgia Tech Athletics, the College of Sciences will bring #IYPT2019GT to McCamish Pavilion. Fans will have a chance to play games with the periodic table and element cards featuring the Yellow Jackets basketball team and Georgia Tech researchers. Prizes await lucky winners.  

"This kick-off event for Georgia Tech's year-long celebration of the periodic table is a great opportunity to bring chemistry to the public's attention and to illustrate its relevance to all of us – scientists, sports fans, and athletes," says David Collard, the College of Sciences' interim dean.

“Georgia Tech Athletics is proud to partner with the College of Sciences to celebrate the 150th anniversary of the periodic table of elements,” Director Todd Stansbury says. “Such a collaboration is uniquely ‘Georgia Tech,’ as we offer our student-athletes the opportunity to compete at the highest level of collegiate athletics, while they receive an education at one of the nation’s leading research universities. We celebrate this combination, as it has proven to produce young people who change the world.”

Brief History of the Periodic Table
Using a set of notecards à la classic card game solitaire, Russian chemist Dmitri Mendeleev sorted and resorted the cards, each representing one element, trying to find a pattern using the elements’ weights and properties. He cracked the code after several sleepless days.

For decades before Mendeleev, scientists had been searching for patterns in the elements. Many other arrangements had been proposed, including one cylindrical design. Mendeleev succeeded where others failed – his table correctly placed more elements than any other.

Critically, too, Mendeleev’s table left gaps for elements yet to be discovered. His table included just over 50 elements, and it wasn’t imminently clear: Were there more elements? How many?

As we now know, many more elements came to light. Thanks to those empty spaces, Mendeleev’s powerful theoretical tool predicted newcomers with startling success. His spot-on predictions of hypothetical elements’ basic properties – atomic mass, atomic number, and reactivity – guided researchers into discovering new elements.

Major changes to Mendeleev’s design occurred as more elements were discovered. For example, the discovery of the noble gases in the 1890s led to the addition of an entirely new column (also called a group). The lanthanides and actinides, those two rows (or periods) at the bottom, were placed below the existing table to retain its basic shape. The periodic table is still being updated to this day: elements 113, 115, 117, and 118 were added in November 2016.

#IYPT2019GT Activities and Events
Every week, the School of Chemistry and Biochemistry will highlight two elements in social media through videos and haikus. And every month, a student, faculty, or staff will expound on a favorite element in a short video.

The periodic table and chemical elements will be a topic in Georgia Tech’s GT 1000 and various Writing & Communication courses. Classes in the School of Music and the School of Industrial Design will use the periodic table as inspiration for projects. The 2019 Clough Art Crawl will have a special section and prizes for submissions inspired by the periodic table or chemical elements.

In February, the Frontiers in Science Lecture Series on the periodic table will commence. Lectures will explore topics from the origin of the chemical elements to the economic, societal, and geopolitical consequences of elements yet undiscovered or in scarce supply. Among the lecturers is bestselling author Sam Kean. His book “The Disappearing Spoon” reveals the periodic table as a treasure trove of passion, adventure, betrayal, and obsession.

Here is a partial list of events. Full information is available at periodictable.gatech.edu.

  • January 22 The Periodic Table at Georgia Tech vs Notre Dame. Go Yellow Jackets!
  • February
    • Frontiers in Science: How the Universe Made the Elements
    • Water, in Three Movements, Georgia Tech Laptop Orchestra, School of Music
  • March
    • Frontiers in Science: Celebrating Silicon: Its Success, Hidden History, and Next Act
    • Periodic Table and the Chemical Elements in Clough Art Crawl
    • Periodic Table and the Chemical Elements in Atlanta Science Festival Expo
  • April
    • Frontiers in Science: Mathematical Mysteries of the Periodic Table
    • Frontiers in Science: The Periodic Table: A Treasure Trove of Passion, Adventure, Betrayal, and Obsession
  • June
    • Halloween in June: Periodic Table Costume Party and Variety Show
  • August
    • Chemical Element Scavenger Hunt
  • September
    • Frontiers in Science: The Elusive End of the Periodic Table: Why Chase It?
  • October
    • Frontiers in Science: Turning Sour, Bloated, and Out of Breath: Ocean Chemistry under Global Warming
  • November
    • Frontiers in Science, The Geopolitics of the Rare and Not-So-Rare Elements
    • Periodic Table Celebration Exhibit
  • December 
    • Periodic Table Celebration Exhibit

Keep up with #IYPT2019GT by checking periodictable.gatech.edu periodically. Follow the College of Sciences on Facebook and Twitter. We look forward to celebrating #IYPT2019GT with you!

December 18, 2018

Susan Embretson has won the 2019 Career Award of the Psychometric Society. A professor in the School of Psychology, Embretson is the first woman to win the prestigious prize.

Psychometrics concerns the development of psychology as a quantitative rational science, including the advancement of theory and methodology for behavioral data analysis in psychology, education, and the social and behavioral sciences generally.

The award is for lifetime achievement. It honors individuals whose publications, presentations, and professional activities over a career have had widespread positive impact on the field. Nominees for the award must have demonstrated excellence in psychometric research over a minimum of 25 years.

Winners’ contributions include theoretical or methodological developments, applications of psychometric theory and methods, and innovative ideas that have significantly affected psychometric practices.

Embretson will receive the award during the 2019 annual international meeting of the Psychometric Society, on July 15-19, 2019, in Santiago, Chile. In that meeting, she will give a keynote lecture titled “Modeling Cognitive Processes, Skills and Strategies in Item Responses: Implications for Test and Item Design.”

“My interactions with colleagues at the Psychometric Society have greatly impacted the quality of my research,” Embretson says. “I feel very honored to receive this award.” 

Embretson’s research interests include explanatory item response theory models, automatic item generation, and dynamic measurement.

She has served as president of the Psychometric Society, the Society of Multivariate Psychology, and the American Psychological Association’s Division of Measurement, Evaluation & Statistics.

Recognition of her research on interfacing cognitive psychology with psychometric models includes the Saul Sells Award for Distinguished Multivariate Research, from the Society for Multivariate Experimental Psychology, and the Career Contribution Award, from the National Council on Measurement in Education.

January 8, 2018

For the sixth year in a row, the Georgia Tech community will partake of a community meal to discuss the life and legacy of civil rights leader Martin Luther King Jr. The meal is called Sunday Supper, even though it takes place during the workweek. The gathering evokes Sunday dinners of yore, when two or more generations of family and friends shared a comforting meal. It was a time to exchange stories, learn family histories, and discuss current events or concerns. 

Conceived by the volunteer organization Points of Light, the Sunday Suppers take place around MLK Day each year. They bring together people from diverse backgrounds to a meal so that they can interact on a personal level and discuss matters that affect their communities.

Sirocus Barnes first attended a Sunday Supper in 2012 in Chicago. “I was so impressed with how the members of various communities came together and had meaningful conversations over a meal,” he recalls. “This is a national program in communities hosted throughout the U.S., and I wanted to bring it to our campus community.”

Through the AmeriCorps program at CEISMC (Center for Education Integrating Science, Mathematics, and Computing), where he is a program director, Barnes organized the first MLK Sunday Supper at Georgia Tech, on January 2013. Since 2014, the event has become a part of Georgia Tech’s MLK celebration events.

Barnes continues to secure funding and facilitators for the event. Sponsors include CEISMC and the College of Sciences. Barnes works with the Georgia Tech MLK Celebration Planning Committee to connect the supper to the annual theme, which is “Actualizing the Dream: The Future of Nonviolent Political Protest” for 2018. 

The gathering evokes Sunday dinners of yore, when two or more generations of family and friends shared a comforting meal. It was a time to exchange stories, learn family histories, and discuss current events or concerns. 

College of Sciences Dean and Sutherland Chair Paul M. Goldbart has served as a facilitator in these suppers and looks forward participating in this year’s event. “I suspect that everyone who gathers for these suppers comes away feeling as I do: reenergized to fulfill our community’s commitment to the full embrace and celebration of diversity,” Goldbart says. “I imagine that these feelings will be even more pronounced this year, as we move toward the 50th anniversary of Dr. King’s assassination.”  

MLK Sunday Supper is a unique event that brings staff, faculty, and students together toward Martin Luther King Jr.’s vision of a society where skin color is not a factor in how people are treated.  “Meaningful conversations about serious issues facing our world, country, and community are important,” Barnes says. “I am thankful that the MLK Sunday Supper allows our campus community and opportunity to have those conversations.”

This year’s MLK Sunday Supper will take place on Thursday, Jan. 18, 6-8 PM, at the Bill Moore Student Success Center. To participate, register here.

January 8, 2018

Psssst, mud crabs, time to hide because blue crabs are coming to eat you! That’s the warning the prey get from the predators’ urine when it spikes with high concentrations of two chemicals, which researchers have identified in a new study.

Beyond decoding crab-eat-crab alarm triggers, pinpointing these compounds for the first time opens new doors to understanding how chemicals invisibly regulate marine wildlife. Insights from the study by researchers at the Georgia Institute of Technology could someday contribute to better management of crab and oyster fisheries, and help specify which pollutants upset them.

In coastal marshes, these urinary alarm chemicals, trigonelline and homarine, help to regulate the ecological balance of who eats how many of whom -- and not just crabs.

Blue crabs, which are about hand-sized and are tough and strong, eat mud crabs, which are about the size of a silver dollar and thin-shelled. Mud crabs, on the other hand, eat a lot of oysters, but when blue crabs are going after mud crabs, the mud crabs hide and freeze, so far fewer oysters get eaten than usual.

Humans are part of the food chain, too, eating oysters as well as blue crabs that boil up a bright orange. The blue refers to the color of markings on their appendages before they’re cooked. Thus, the blue crab urinary chemicals influence seafood availability for people, as well.

Predator pee-pee secrets

The fact that blue crab urine scares mud crabs was already known. Mud crabs duck and cover when exposed to samples taken in the field and in the lab, even if the mud crabs can’t see the blue crabs yet. Digestive products, or metabolites, in blue crab urine trigger the mud crabs’ reaction, which also makes them stop foraging for food themselves.

“Mud crabs react most strongly when blue crabs have already eaten other mud crabs,” said Julia Kubanek, who co-led the study with fellow Georgia Tech professor Marc Weissburg. “A change in the chemical balance in blue crab urine tells mud crabs that blue crabs just ate their cousins,” Kubanek said.

Figuring out the two specific chemicals, trigonelline and homarine, that set off the alarm system, out of myriad candidate molecules, is new and has been a challenging research achievement.

“My guess is that there are many hundreds of chemicals in the animal’s urine,” said Kubanek, who is a professor in Georgia Tech’s School of Biological Sciences, in its School of Chemistry and Biochemistry, and who is also Associate Dean for Research in Georgia Tech’s College of Sciences.

The researchers applied technology and methodology from metabolomics, a relatively new field used principally in medical research to identify small biomolecules produced in metabolism that might serve as early warning signs of disease. Kubanek, Weissburg, and first author Remington Poulin published their results the week of January 8, 2017, in the journal Proceedings of the National Academies of Science.

The research was funded by the National Science Foundation.

Peedle in a haystack

Trigonelline has been studied, albeit loosely, in some diseases, and is known as one of the ingredients in coffee beans that, upon roasting, breaks down into other compounds that give coffee its aroma. Homarine is very similar to trigonelline, and, though apparently less studied, it’s also common.

“These chemicals are found in many places,” Kubanek said. But picking them out of all those chemicals in blue crab urine for the first time was like finding two needles in a haystack.

Often, in the past, researchers trying to narrow down such chemicals have started out by separating them out in arduous laboratory procedures then testing them one at a time to see if any of them worked. There was a good chance of turning up nothing.

The Georgia Tech researchers went after all the chemicals at one time, the whole haystack, using mass spectrometry and nuclear magnetic resonance spectroscopy.

“We screened the entire chemical composition of each sample at once,” Kubanek said. “We analyzed lots and lots of samples to fish out chemical candidates.”

Crabs are ‘walking noses’

The researchers discovered spikes in about a dozen metabolites after blue crabs ate mud crabs. They tested out those pee chemicals that spiked on the mud crabs, and trigonelline and homarine distinctly made them crouch.

“Trigonelline scares the mud crabs a little bit more,” Kubanek said.

More specifically, high concentrations of either of the two did the trick. “It’s clear that there was a dose-dependent response,” said Weissburg, who is a professor in Georgia Tech’s School of Biological Sciences. “Mud crabs have evolved to hone in on that elevated dose.”

“Most crustaceans are walking noses,” Weissburg said. “They detect chemicals with sensors on their claws, antennae and even the walking legs. The compounds we isolated are pretty simple, which suggests they might be easily detectable in a variety of places on a crab. This redundancy is good because it increases the likelihood that the mud crabs get the message and not get eaten.”

Ecological and fishery effects

Evolution preserved the mud crabs with the duck-and-cover reaction to the two chemicals, which also influenced the ecological balance, in part by pushing blue crabs to look for more of their food elsewhere. But it influenced other animal populations as well.

“These chemicals are staggeringly important,” Weissburg said. “The scent from a blue crab potentially affects a large number of mud crabs, all of which stop eating oysters, and that helps preserve the oyster populations.”

All of that also impacts food sources for marine birds and mammals: Just by the effects of two chemicals, and there are so many more chemical signals around. “It’s hard for us to appreciate the richness of this chemical landscape,” Weissburg said.

As scientists learn more, influencing these systems could become useful to ecologists and the fishing industry.

“We might even be able to use these chemicals to control oyster consumption by predators to help preserve these habitats, which are critical, or to help oyster farmers. That’s becoming important in Georgia fisheries,” Weissburg said.

Pollutants in pesticides and herbicides are known to interfere with estuaries’ ecologies. “It will be a lot easier to test how strong this is by knowing specific ecological chemicals,” Weissburg said.

Fear-o-mone small molecules

By the way, trigonelline and homarine are not pheromones.

“Pheromones are signaling molecules that have a function within the same species, like to attract mates,” Kubanek said. “And blue crabs and mud crabs are not the same species.”

“In this case, the mud crabs have evolved to chemically eavesdrop on the blue crabs’ pee. You might call trigonelline and homarine fear-inducing cues.”

Identifying such metabolites, also called small molecules, and their effects is the latest chapter in constructing the catalog of life molecules. “Everyone knows about the human genome project, identifying genomes; then came transcriptomes (molecules that transcribe genes),” Kubanek said. “Now we’re pretty far along with proteomics (identifying proteins), but we’re just now figuring out metabolomes.”

The paper was co-authored by Serge Lavoie, Katherine Siegel, and David Gaul. The research was funded by the National Science Foundation Division of Ocean Sciences (grant OCE-1234449). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsor.

January 16, 2018

At the start of his class on differential equations, Rafael de la Llave invites students to watch a mesmerizing demonstration.

He hangs two one-inch-diameter hex nuts from a clothesline through strings of the same length. With both hex nuts at rest, the School of Mathematics professor taps one slightly.

Given the slight energy input, the nut moves. In a while, the nut at rest also starts to swing. Eventually, a dance commences, the two hex nuts gracefully oscillating as they transfer energy from one to the other.

When more oscillators are involved, beautiful geometric patterns emerge, as this video shows.    

Designers of space missions can harness the dynamics creating these dazzling motions to save fuel. “If we could make the mathematical details very explicit, we can make these work to our advantage,” de la Llave says. “We could move spacecraft with very small amounts of fuel. We could extend the life of satellites – or send robots to the moon – inexpensively.”

NASA recently awarded a $100,000 grant to de la Llave, Marian Gidea of Yeshiva University, and Rodney Anderson of NASA’s Jet Propulsion Laboratory (JPL)to take the first steps to realize the potential of mathematics to lower the fuel cost of space travel. The project – “Accelerating Diffusion to Enable Rapid Tour Design” – has a duration of one year.  

As part of the project goals, this week in the Skiles Building, space mission designers from JPL and mathematicians from Georgia Tech and Yeshiva University are gathering for a four-day workshop. The participants will work together with the mathematical tools of the Arnold diffusion mechanism and trajectory design. The goal is to incorporate what is also known as the “butterfly effect” – which is the ability of minuscule changes to cause gigantic effects in certain systems – into space mission design.

“If we want to go around jumping from moon to moon, applying these new advances in mathematics can help us get there at much, much lower cost, making such a mission so much more doable.”

The Arnold diffusion mechanism is the underlying mathematical concept. Both de la Llave and Gidea are world-renowned experts in this field.

“In a nutshell, the Arnold diffusion mechanism states that small amounts of force, applied at the right moments, can produce large effects over time,” Gidea explained last year. “A familiar example is pushing a playground swing: with a tiny push on the swing each time it comes back to you, the amplitude of the swing will keep increasing.

“In the case of space missions, this small forcing translates into firing the rocket’s engine at the right place and the right moment to accelerate in orbit when the natural dynamics is slow.” Other possible small forcings could be the tugs of gravitational tides induced by stars, planets, moons, and even asteroids.

At other times, “the spacecraft will coast along the space superhighway at zero cost,” Gidea said.

“Celestial bodies are moving all the time,” de la Llave says. “And they generate forces that depend on time. If you can ride the wave of those forces, then you can move and accelerate using just the gravitational forces of astronomical objects.”

The Arnold diffusion mechanism is rooted in the Kolmogorov-Arnold-Moser (KAM) theorem. The theorem provides a general framework for understanding what happens when a simple physical system is modified slightly, according to School of Mathematics Professor Howard “Howie” Weiss. “Rafael and others played a big role in extending the KAM theorem,” Weiss says. “Rafael is extremely modest. He is probably the world’s leader in this business.”

Design of space mission routes historically has been based mostly on patching orbits of conical geometry. Recent mathematical advances in the Arnold diffusion mechanism have uncovered other geometries that reveal new potential pathways leveraging the gravitational dynamics in space. Adding small maneuvers at precise times and locations to the pathways found via the Arnold diffusion mechanism could significantly drop the cost of space missions.

While de la Llave and Gidea work on the mathematics, JPL’s Anderson will focus on applying the mathematical methods to mission concepts. Anderson is an expert on the application of dynamical systems theory to trajectory design problems. He is the coauthor of a 2013 NASA monograph that explores the use of low-energy paths to transfer a spacecraft from Earth to its moon.  

One space endeavor of great interest is to visit the moons of Jupiter systematically, de la Llave says. “If we want to go around jumping from moon to moon, applying these new advances in mathematics can help us get there at much, much lower cost, making such a mission so much more doable.”

January 17, 2018

Mark E. Hay, Regents Professor and Harry and Linda Teasley Chair in the School of Biological Sciences at Georgia Tech, is the recipient of the 2018 Gilbert Morgan Smith Medal of the National Academy of Sciences. The award recognizes excellence in published research on marine and freshwater algae.

The 2018 Smith Medal recognizes Hay’s research into algal science, which has influenced a generation of scientists and revealed numerous insights into the declining health of ocean ecosystems. His research has enormous implications for coral reef recovery, along with the ecosystems and human societies that depend upon these reefs. 

Hay developed algal chemical ecology as the major model for marine chemical ecology, a field that he cofounded. He elucidated how chemical cues and signals from algae structure marine and aquatic populations, communities, and ecosystems.

An experimental ecologist, Hay led scientific expeditions to remote regions to study the processes and mechanisms that control the organization, function, and sustainability of natural ecosystems. His studies of seaweed – which comprise red, brown, and green marine algae – have revolutionized the practice of marine conservation and management.

“By conducting phycological studies within the broader intellectual framework of ecology and evolution, Mark extended the impact of his algal studies,” says James H. Tumlinson, the Ralph O. Mumma Professor of Entomology and Director of the Center for Chemical Ecology at Pennsylvania State University. “His research has informed the conservation of coral reefs and helped predict how coastal ecosystems will be altered by global change.”

Hay’s 40-year academic career features many discoveries about the natural history of seaweeds. Initially, he focused on the effects of physical factors and biotic interactions on algal ecology, Tumlinson says. Then Hay turned to seaweed-herbivore interactions, seaweed chemical defenses, and the roles they played in deterring herbivores, overcoming competitors, and organizing seaweed communities.

Insights from his research enabled Hay to predict that particular combinations of herbivores would be needed to stop seaweed damage to corals and the algal domination of reefs. “By manipulating herbivore diversity alone, Hay’s lab was able to prevent coral mortality and increase coral growth, thus demonstrating the applied potential of his research,” Tumlinson says. “More recent work demonstrates the critical role of algal chemical cues in fish and coral recruitment on Pacific reefs and the impact of these chemical cues on reef resilience.”

“His research has informed the conservation of coral reefs and helped predict how coastal ecosystems will be altered by global change.”

The Smith Medal is the latest of significant honors bestowed upon Hay. In 2016, Hay reaped three awards: He received the International Society of Chemical Ecology (ICSE) Silver Medal, the society’s highest honor. He was named Fellow of the Ecological Society of America. And Georgia Tech named Hay the recipient of the 2016 Outstanding Faculty Research Author Award, for producing the most impactful publications from Georgia Tech in the previous five years.

“We bask in the glow of Mark’s accomplishment,” says College of Sciences Dean and Sutherland Chair Paul M. Goldbart. “Through his research and education efforts, Mark serves as a role model inspiring countless students and colleagues. In his communication efforts, Mark sets a superb example that so many more of us need to emulate.”

Indeed, Hay’s outstanding scholarship is matched by his zeal in communicating his research and its ecological implications in ways that are understandable to the public. He has written articles for the New York Time’s Scientists At Work blog and given numerous interviews to broadcast media, including NPR, BBC, CBS, ABC, Voice of America, and Voice of Russia.

“Because the ecosystem I study is disappearing,” Hay says, “I’ve perceived the need to focus on senior decision makers that can make a difference in the very near term.” Lately, he has been speaking about environmental challenges at corporations like The Coca-Cola Company and at community organizations, such as Rotary Clubs. He continues to educate the world about the plight of endangered ecosystems by organizing international symposia and web-based global discussions.

Presented every three years, the Smith Medal consists of a gold-plated bronze medal and a $50,000 prize. The bequest of Helen P. Smith in memory of her husband, Gilbert Morgan Smith, established the award in March 1968. Gilbert Smith was a renowned botanist, a member of the National Academy of Sciences, and the first president of the Phycological Society of America.

January 17, 2018

Big data and data mining have provided several breakthroughs in fields such as health informatics, smart cities and marketing. The same techniques, however, have not delivered consistent key findings for climate change.

There are a few reasons why. The main one is that previous data mining work in climate science, and in particular in the analysis of climate teleconnections, has relied on methods that offer rather simplistic “yes or no” answers. 

“It’s not that simple in climate,” said Annalisa Bracco, a professor in Georgia Tech’s School of Earth and Atmospheric Sciences. “Even weak connections between very different regions on the globe may result from an underlying physical phenomenon. Imposing thresholds and throwing out weak connections would halt everything. Instead, a climate scientist’s expertise is the key step to finding commonalities across very different data sets or fields to explore how robust they are.”

And with millions of data points spread out around the globe, Bracco said current models rely too much on human expertise to make sense of the output. She and her colleagues wanted to develop a methodology that depends more on actual data rather than a researcher’s interpretation.

That’s why the Georgia Tech team has developed a new way of mining data from climate data sets that is more self-contained than traditional tools. The methodology brings out commonalities of data sets without as much expertise from the user, allowing scientists to trust the data and get more robust — and transparent — results.

The methodology is open source and currently available to scientists around the world. The Georgia Tech researchers are already using it to explore sea surface temperature and cloud field data, two aspects that profoundly affect the planet’s climate.

“There are so many factors — cloud data, aerosols and wind fields, for example — that interact to generate climate and drive climate change,” said Athanasios Nenes, another College of Sciences climate professor on the project. “Depending on the model aspect you focus on, they can reproduce climate features effectively — or not at all. Sometimes it is very hard to tell if one model is really better than another or if it predicts climate for the right reasons.”

Nenes says the Georgia Tech methodology looks at everything in a more robust way, breaking the bottleneck that is typical of other model evaluation and analysis algorithms. The methodology, he says, can be used for observations, and scientists don’t need to know anything about computer code and models.

“The methodology reduces the complexity of millions of data points to the bare essentials —sometimes as few as 10 regions that interact with each other,” said Nenes. “We need to have tools that reduce the complexity of model output to understand them better and evaluate if they are providing the correct results for the right reasons.”

To develop the methodology, the climate scientists partnered with Constantine Dovrolis and other data scientists in Georgia Tech’s College of Computing. Dovrolis said it’s exciting to apply algorithmic and computational thinking in problems that affect everyone in major ways, such as global warming.”

“Climate science is a ‘data-heavy’ discipline with many intellectually interesting questions that can benefit from computational modeling and prediction,” said Dovrolis, a professor in the School of Computer Science, “Cross-disciplinary collaborations are challenging at first — every discipline has its own language, preferred approach and research culture — but they can be quite rewarding at the end.”

The paper, “Advancing climate science with knowledge-discovery through data mining,” is published in Climate and Atmospheric Science, a Nature journal.

The development of the methodology was supported by the U.S. Department of Energy (grant DE-SC0007143) and the National Science Foundation (grant DMS-1049095). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsors.

January 26, 2018

In the lab of Colin Parker in the Howey Physics Building, certain atoms are cooled to ten-thousandth of a degree above absolute zero (0 kelvin). Parker accomplishes this feat with equipment laid out on a surface that is similar in size to about four eight-seat rectangular dining tables laid side by side. Cables and wires and lasers and vacuum lines crisscross the platform, keeping a few million ultracold atoms suspended in a vacuum chamber about eight cubic inches in volume.

Thus begins Parker’s adventure into the land of ultracold atomic Kondo impurities. The atoms need to get down to a millionth of a degree above 0 kelvin before Parker could start experiments to discover the nature of Kondo impurities. A three-year, $450,000 Air Force Office of Scientific Research Young Investigator Award makes possible Parker’s journey, which commenced in December 2017.

Kondo impurities are magnetic contaminants embedded in a metal crystal that cause a unique behavior as the metal cools. When electrons hit the impurity, they bounce off, the rebound sometimes accompanied by a change in the electron’s internal state. As the metal cools to lower and lower temperatures, the internal-state flipping occurs at increasing probability. Eventually, the metal cools to a point when all the electrons bouncing off the impurity undergo an internal-state flip.  

Strange things happen at ultracold temperatures, when thermal energy is removed from a system and what remains is only the intrinsic energy of the particles in it. So-called quantum systems are the subject of intense curiosity, because of the interesting materials they have yielded.

“Quantum systems have led to materials that we use, including the materials in computer hard drives,” says Parker, an assistant professor in the School of Physics. Other examples are high-temperature superconductors, which conduct electrical current without resistance at operational temperatures higher than those of traditional superconductors, and heavy fermion materials, in which electrons appear to be hundreds of times as massive as normal electrons. “It’s possible they will turn up things we can use to make maglev trains,” Parker says.

The Kondo effect refers to the formation of a cloud of electrons screening a magnetic impurity. It is known to lead to high resistivity at low temperatures. Why all these things happen is what Parker wants to find out. 

Parker will use a simulation approach to discover the inner workings of the Kondo effect. Instead of studying materials directly, Parker will use atoms to make inferences about the materials. Cesium will stand-in for the magnetic impurity, and lithium will take the role of the electrons hitting and then bouncing off the impurity.

“The advantage with atoms is that we can measure a lot of things that would be tough to measure with solid materials,” Parker says. “To measure on the time scale for an electron to move from one atom to neighbor is extremely difficult. In our system, things move more slowly and they are farther apart.” With the quantum simulation system, Parker could also easily set different experimental conditions and observe the consequent outcomes.

“We’re only just starting to get to understand how to use superconductors and other exotic quantum materials in technology,” Parker says. “Down the road, we can imagine applications in quantum computing. Another thing would be sensors. Really far out but possible, the physics we uncover could have major implications for the power grid.”

January 29, 2018

Researchers have published the first part of what they expect to be a database showing the kinetics involved in producing colloidal metal nanocrystals – which are suitable for catalytic, biomedical, photonic and electronic applications – through an autocatalytic mechanism. 

In the solution-based process, precursor chemicals adsorb to nanocrystal seeds before being reduced to atoms that fuel growth of the nanocrystals. The kinetics data is based on painstaking systematic studies done to determine growth rates on different nanocrystal facets — surface structures that control how the crystals grow by attracting individual atoms. 

In an article published December 11 in the journal Proceedings of the National Academy of Sciences, a research team from the Georgia Institute of Technology provided a quantitative picture of how surface conditions controlled the growth of palladium nanocrystals. The work, which will later include information on nanocrystals made from other noble metals, is supported by the National Science Foundation.

“This is a fundamental study of how catalytic nanocrystals grow from tiny seeds, and a lot of people working in this field could benefit from the systematic, quantitative information we have developed,” said Younan Xia, professor and Brock Family Chair in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. “We expect that this work will help researchers control the morphology of nanocrystals that are needed for many different applications.”

A critical factor controlling how nanocrystals grow from tiny seeds is the surface energy of the crystalline facets on the seeds. Researchers have known that energy barriers dictate the surface attraction for precursors in solution, but specific information on the energy barrier for each type of facet had not been readily available.

“Typically, the surface of the seeds that are used to grow these nanocrystals has not been homogenous,” explained Xia, who is also the Georgia Research Alliance Eminent Scholar in Nanomedicine and holds joint appointments in School of Chemistry & Biochemistry and School of Chemical & Biomolecular Engineering. “You may have different facets on the crystals, which depend on the arrangement of the atoms below them. From the standpoint of precursors in the solution around the seeds, these surfaces have different activation energies which determine how difficult it will be for the precursors or atoms to land on each surface.”

Xia’s research team designed experiments to assess the energy barriers on various facets, using seeds in a variety of sizes and surface configurations chosen to have only one type of facet. The researchers measured both the growth of the nanocrystals in solution and the change in concentration of palladium tetrabromide (PdBr4 2-) precursor salt.

“By choosing the right precursor, we can ensure that all the reduction we measure is on the surface and not in the solution,” he explained. “That allowed us to make meaningful measurements about the growth, which is controlled by the type of facet, as well as presence of a twin boundary, corresponding to distinctive growth patterns and end results.”

Over the course of nearly a year, visiting graduate research assistant Tung-Han Yang studied the nanocrystal growth using different types of seeds. Rather than allowing nanocrystal growth from self-nucleation, Xia’s team chose to study growth from seeds so they could control the initial conditions.

Controlling the shape of the nanocrystals is critical to applications in catalysis, photonics, electronics and medicine. Because these noble metals are expensive, minimizing the amount of material needed for catalytic applications helps control costs. 

“When you do catalysis with these materials, you want to make sure the nanocrystals are as small as possible and that all of the atoms are exposed to the surface,” said Xia. “If they are not on the surface, they won’t contribute to the activity and therefore will be wasted.”

The ultimate goal of the research is a database that scientists can use to guide the growth of nanocrystals with specific sizes, shapes and catalytic activity. Beyond palladium, the researchers plan to publish the results of kinetic studies for gold, silver, platinum, rhodium and other nanocrystals. While the pattern of energy barriers will likely be different for each, there will be similarities in how the energy barriers control growth, Xia said.

“It’s really how the atoms are arranged on the surface that determines the surface energy,” he explained. “Depending on the metals involved, the exact numbers will be different, but the ratios between the facet types should be more or less the same.”

Xia hopes that the work of his research team will lead to a better understanding of how the autocatalytic process works in the synthesis of these nanomaterials, and ultimately to broader applications.

“If you want to control the morphology and properties, you need this information so you can choose the right precursor and reducing agent,” said Xia. “This systematic study will lead to a database on these materials. This is just the beginning of what we plan to do.”

In addition to the researchers already mentioned, the study also included Shan Zhou, Kyle Gilroy, Legna Figueroa-Cosme, Yi-Hsien Lee and Jenn-Ming Wu.

This work was supported in part by a research grant from the NSF (CHE 1505441) and startup funds from the Georgia Institute of Technology. The electron microscopy studies were performed at Georgia Tech’s Institute for Electronics and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure supported by the NSF (ECCS-1542174).

CITATION: Tung-Han Yang, et al., “Autocatalytic surface reduction and its role in controlling seed-mediated growth of colloidal metal nanocrystals,” (Proceedings of the National Academy of Sciences, 2017). http://dx.doi.org/10.1073/pnas.1713907114

Research News
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Media Relations Contact: John Toon (jtoon@gatech.edu) (404-894-6986).

Writer: John Toon

EDITOR'S NOTE: This story was first published on Dec. 26, 2017 at the Research Horizons website. It was revised as follows: a subtitle was added. 

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