Experts examine what’s now, what’s next for sea-level rise
The Brunswick News, Jan 22
The hope is that in 80 years we're not submerged in water.
Kim Cobb joined community leaders and the state's top experts in sea-level rise at College of Coastal Georgia to take a good look at sea-level rise in Glynn County, what's to come, and what the community can do to move forward. The panel discussed predictions, cultural and socioeconomic risks assocated with sea-level rise, and flood insurance.
Kim Cobb is the the Georgia Power Chair and ADVANCE Professor in the School of Earth and Atmospheric Sciences.
Multiple excitons make a surprise appearance in 2D hybrid perovskites
Physics World, Jan 22
An international team led by researchers from the College of Sciences has made a surprising discovery in the field of 2D materials. Their finding could open a range of novel device applications, but it also raises many questions about the mechanisms involved.
From the School of Physics: Felix Thouin, Carlos Silva, Ajay Ram Srimath Kandada
From the School of Chemistry and Biochemistry: David A. Valverde-Chavez, Ilaria Bargigia, Carlos Silva, Ajay Ram Srimath Kandada
Read the original paper, published in Nature Materials.
Jeanine Williams launches the 2019 monthly feature "My Favorite Element." This series is part of Georgia Tech's celebration of 2019 as the International Year of the Periodic Table of Chemical Elements, #IYPT2019GT. Each month a member of the Georgia Tech community will share his/her favorite element via video.
A biochemistry major, Williams is also a two-time NCAA All-American student athlete. She runs sprints and hurdles and is the reigning ACC champion in the 60-meter hurdles.
Williams will graduate in May 2019. She plans to run track professionally after graduation and to try out for the 2020 Summer Olympics in Tokyo. Her ultimate goal is to attend medical school and become a pediatric surgeon.
The native of Kingston, Jamaica, is also a member of the 2018 All-Academic Team for the U.S. Track & Field and Cross Country Coaches Association.
Her favorite element is .... Watch the video!
Renay San Miguel, communications officer in the College of Sciences, produced and edited the videos in this series.
Trying to explain how DNA and RNA evolved to form such neat spirals has been a notorious enigma in science. But a new study suggests the rotation may have occurred with ease billions of years ago when RNA’s chemical ancestors casually spun into spiraled strands.
In the lab, researchers at the Georgia Institute of Technology were surprised to see them do it under conditions thought to be common on Earth just before first life evolved: in plain water, with no catalysts, and at room temperature.
The neat spiraling also elegantly integrated another compound which today forms the backbone of RNA and DNA. The resulting structure had features that strongly resembled RNA.
Pivotal twists
The study has come a step closer to answering a chicken-egg question about the evolutionary path that led to RNA (from which DNA later evolved): Did the spiral come first, and did this structure influence which molecular components made it later into RNA because they fit well into the spiral?
“The spiraling could have had a reinforcing effect. It could have facilitated the molecules getting connected together that have the same chirality (curve) to connect into a common backbone that is compatible with the helical twist,” said the study’s principal investigator Nicholas Hud, a Regents Professor in Georgia Tech’s School of Chemistry and Biochemistry.
The researchers published the new study in the journal Angewandte Chemie in December 2018. The research was funded by the National Science Foundation and the NASA Astrobiology Program under the Center for Chemical Evolution. The center is headquartered at Georgia Tech, and Hud is its principal investigator.
The study’s resulting polymers were not RNA but could be have been an important intermediate step in the early evolution of RNA. For building blocks, the researchers used base molecules referred to as “proto-nucleobases,” highly suspected to be precursors of nucleobases, main components that transport genetic code in today’s RNA.
[Thinking about grad school? Here's how to apply to Georgia Tech.]
Nucleobase paradox
The study had to work around a paradox in chemical evolution:
Making RNA or DNA using their actual nucleobases in the lab without the aid of the enzymes of living cells that usually do this job is more than a herculean task. Thus, although RNA and DNA are ubiquitous on Earth now, their evolution on pre-life Earth would appear to have been an anomaly requiring erratic convergences of extreme conditions.
By contrast, the Georgia Tech researchers’ model of chemical evolution holds that precursor nucleobases self-assembled easily to into ancestral prototypes -- that were polymer-like and referred to as assemblies -- which later evolved into RNA.
“We would call these ‘proto-nucleobases’ or ‘ancestral nucleobases,’” Hud said. “For our overall model of chemical evolution, we’re saying that these proto-nucleobases, which self-assemble into these long strands, could have been part of a very early stage before modern nucleobases were incorporated.”
One main suspected proto-nucleobase in this experiment -- and in previous experiments on the possible the evolution of RNA -- was triaminopyrimidine (TAP). Cyanuric acid (CA) was another. The researchers highly suspect TAP and CA were parts of a proto-RNA.
The chemical bonds that hold together assemblies of the two suspected proto-nucleobases were surprisingly strong but non-covalent, which is akin to connecting two magnets. In RNA the main bonds holding together modern nucleobases are covalent bonds, akin to welding, and enzymes make those bonds in cells today.
Helical biases
A helix can spiral two ways, left-handed or right-handed. In chemistry, a molecule can also be handed, or chiral, making for “L” or “D” forms of the molecule.
Incidentally, the building blocks of today’s RNA and DNA are all the D form, which make a right-handed helix. Why they evolved like this is still a mystery.
Batches of TAP and CA the researchers started out with produced roughly equal amounts of right and left-handed helices, but something stood out: Whole regions of a batch were biased in one direction and were separate from other regions that spiraled mostly the other way.
“The propensity for the molecules to choose one helical direction was so strong that large regions of the batches were made up predominantly of assemblies that were unidirectionally twisted,” Hud said.
This was surprising because the individual molecules of TAP and CA had no chirality of their own, neither L nor D. Still, the twists had a preferred direction.
‘world record’
The researchers added two more experiments to test how strongly their RNA-like assemblies preferred making one-handed helices.
First, they introduced a smidgeon of compounds similar to TAP and CA, but which had L or D chirality, to nudge the spiraling direction. The whole batch conformed to the chirality of the respective additive, resulting in assemblies twisting in a unified direction as helices do in RNA and DNA today.
“It was the new world record for the smallest amount of a chiral dopant (additive) that would flip a whole solution,” said Suneesh Karunakaran, the study’s first author and a graduate researcher in Hud’s lab. “This demonstrated how easy it would be in nature to get abundant amounts of unified helices.”
Second, they put the sugar compound ribose-5-phosphate together with TAP to more closely emulate the current building blocks of RNA. The ribose fell into place, and the resulting assembly spiraled in a direction dictated by the ribose chirality.
“This molecule easily formed an RNA-like assembly that was surprisingly stable, even though the pieces were only held together by non-covalent bonds,” Karunakaran said.
Evolution revolution
The study’s results under such simple conditions represent a leap forward in experimental evidence for how the helical twist of biomolecules could have already been in place long before life emerged.
The research also expands a growing body of evidence supporting an unconventional hypothesis by the Center for Chemical Evolution, which dispenses with the need for a narrative that rare cataclysms and unlikely ingredients were necessary to produce life’s early building blocks.
Instead, most biomolecules likely arose in several gradual steps, on quiet, rain-swept dirt flats or lakeshore rocks lapped by waves. Precursor molecules with the right reactivity enabled those steps readily and produced abundant materials for further evolutionary steps.
Basement engineer
In the lab, helix self-assemblage was so productive that it outstripped a detection device’s capacity to examine the output. Regions a square millimeter or more in size were packed with unidirectionally spiraled polymer-like assemblies.
“To look at them I had to make adjustments to the equipment,” said Karunakaran. “I punched holes in a foil and put it in front of the beam of our spectropolarimeter.”
That worked but needed improvement, so Hud took to his basement at home to build an automated scanner that could handle the experiment’s bountiful results. It revealed large regions of helices with the same handedness.
Also READ: This actually happened: Strip all the lynchpins from the ribosome and it still works
Brian J. Cafferty, Angela Weigert-Muñoz and Gary B. Schuster of Georgia Tech co-authored the research. It was funded by the National Science Foundation and the NASA Astrobiology Program under the NSF Center for Chemical Evolution (grant CHE-1504217). Nicholas Hud is also Associate Director of the Parker H. Petit Institute for Bioengineering and Bioscience. Any findings, recommendations or conclusions are those of the authors and not necessarily of the funding agencies.
Media relations assistance: Ben Brumfield
(404) 660-1408
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Writer: Ben Brumfield
Led by the College of Sciences, Georgia Tech launched its year-long celebration of 2019, the International Year of the Periodic Table (#IYPT2019), at the Jan. 22 men's basketball game against Notre Dame. The Yellow Jackets prevailed over the Fighting Irish, 63-61.
College of Sciences students, faculty, and staff distributed element cards and guided fans through the periodic table dart game. Scores of fans won periodic table mug beakers and T-shirts, as well as ScienceMatters card holders and sticky note pads. ScienceMatters is the College of Sciences' podcast. It's second season returns in the spring 2019 semester.
Also featured in the Jan. 22 game was biochemistry major and track star Jeanine Williams. At half-time, a video of Williams talking about her favorite element was broadcast on the McCamish jumbotron.
Get visual highlights from the #IYPT2019 kick-off from the video on the right.
The light released from around the first massive black holes in the universe is so intense that it is able to reach telescopes across the entire expanse of the universe. Incredibly, the light from the most distant black holes (or quasars) has been traveling to us for more than 13 billion light years. However, we do not know how these monster black holes formed.
New research led by researchers from Georgia Institute of Technology, Dublin City University, Michigan State University, the University of California at San Diego, the San Diego Supercomputer Center and IBM provides a new and extremely promising avenue for solving this cosmic riddle. The team showed that when galaxies assemble extremely rapidly – and sometimes violently – that can lead to the formation of very massive black holes. In these rare galaxies, normal star formation is disrupted and black hole formation takes over.
The new study finds that massive black holes form in dense starless regions that are growing rapidly, turning upside down the long-accepted belief that massive black hole formation was limited to regions bombarded by the powerful radiation of nearby galaxies. Conclusions of the simulation-based study, reported January 23 in the journal Nature and supported by funding from the National Science Foundation, the European Union and NASA, also finds that massive black holes are much more common in the universe than previously thought.
The key criteria for determining where massive black holes formed during the universe’s infancy relates to the rapid growth of pre-galactic gas clouds that are the forerunners of all present-day galaxies, meaning that most supermassive black holes have a common origin forming in this newly discovered scenario, said John Wise, an associate professor in the Center for Relativistic Astrophysics in Georgia Tech’s School of Physics and the paper’s corresponding author. Dark matter collapses into halos that are the gravitational glue for all galaxies. Early rapid growth of these halos prevented the formation of stars that would have competed with black holes for gaseous matter flowing into the area.
“In this study, we have uncovered a totally new mechanism that sparks the formation of massive black holes in particular dark matter halos,” Wise said. “Instead of just considering radiation, we need to look at how quickly the halos grow. We don’t need that much physics to understand it – just how the dark matter is distributed and how gravity will affect that. Forming a massive black hole requires being in a rare region with an intense convergence of matter.”
When the research team found these black hole formation sites in the simulation they were at first stumped, said John Regan, research fellow in the Centre for Astrophysics and Relativity in Dublin City University. The previously accepted paradigm was that massive black holes could only form when exposed to high levels of nearby radiation.
“Previous theories suggested this should only happen when the sites were exposed to high levels of star-formation killing radiation,” he said. “As we delved deeper, we saw that these sites were undergoing a period of extremely rapid growth. That was the key. The violent and turbulent nature of the rapid assembly, the violent crashing together of the galaxy’s foundations during the galaxy’s birth prevented normal star formation and led to perfect conditions for black hole formation instead. This research shifts the previous paradigm and opens up a whole new area of research.”
The earlier theory relied on intense ultraviolet radiation from a nearby galaxy to inhibit the formation of stars in the black hole-forming halo, said Michael Norman, director of the San Diego Supercomputer Center at UC San Diego and one of the work’s authors. “While UV radiation is still a factor, our work has shown that it is not the dominant factor, at least in our simulations,” he explained.
The research was based on the Renaissance Simulation suite, a 70-terabyte data set created on the Blue Waters supercomputer between 2011 and 2014 to help scientists understand how the universe evolved during its early years. To learn more about specific regions where massive black holes were likely to develop, the researchers examined the simulation data and found ten specific dark matter halos that should have formed stars given their masses but only contained a dense gas cloud. Using the Stampede2 supercomputer, they then re-simulated two of those halos – each about 2,400 light-years across – at much higher resolution to understand details of what was happening in them 270 million years after the Big Bang.
“It was only in these overly-dense regions of the universe that we saw these black holes forming,” Wise said. “The dark matter creates most of the gravity, and then the gas falls into that gravitational potential, where it can form stars or a massive black hole.”
The Renaissance Simulations are the most comprehensive simulations of the earliest stages of the gravitational assembly of the pristine gas composed of hydrogen and helium and cold dark matter leading to the formation of the first stars and galaxies. They use a technique known as adaptive mesh refinement to zoom in on dense clumps forming stars or black holes. In addition, they cover a large enough region of the early universe to form thousands of objects—a requirement if one is interested in rare objects, as is the case here. “The high resolution, rich physics and large sample of collapsing halos were all needed to achieve this result,” said Norman.
The improved resolution of the simulation done for two candidate regions allowed the scientists to see turbulence and the inflow of gas and clumps of matter forming as the black hole precursors began to condense and spin. Their growth rate was dramatic.
“Astronomers observe supermassive black holes that have grown to a billion solar masses in 800 million years,” Wise said. “Doing that required an intense convergence of mass in that region. You would expect that in regions where galaxies were forming at very early times.”
Another aspect of the research is that the halos that give birth to black holes may be more common than previously believed.
“An exciting component of this work is the discovery that these types of halos, though rare, may be common enough,” said Brian O’Shea, a professor at Michigan State University. “We predict that this scenario would happen enough to be the origin of the most massive black holes that are observed, both early in the universe and in galaxies at the present day.”
Future work with these simulations will look at the lifecycle of these massive black hole formation galaxies, studying the formation, growth and evolution of the first massive black holes across time. “Our next goal is to probe the further evolution of these exotic objects. Where are these black holes today? Can we detect evidence of them in the local Universe or with gravitational waves?” Regan asked.
For these new answers, the research team – and others – may return to the simulations.
“The Renaissance Simulations are sufficiently rich that other discoveries can be made using data already computed,” said Norman. “For this reason we have created a public archive at SDSC containing called the Renaissance Simulations Laboratory where others can pursue questions of their own.”
This research was supported by the National Science Foundation through grants PHY-1430152, AST-1514700, AST-161433 and OAC-1835213, by NASA grants NNX12AC98G, 147 NNX15AP39G, and NNX17AG23G, and by Hubble theory grants HST-AR-13261.01, HST-AR-14315.001, and HST-AR-14326. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 699941 (Marie Sklodowska-Curie Actions – “SmartStars). The simulation was performed on the Blue Waters supercomputer operated by the National Center for Supercomputing Applications (NCSA) with PRAC allocation support by the NSF (awards ACI-0832662, ACI-1238993 and ACI-1514580). 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 organizations.
CITATION: John H. Wise, et al., “Formation of massive black holes in rapidly growing pre-galactic gas clouds,” (Nature 2019). http://dx.doi.org/10.1038/s41586-019-0873-4
Renaissance Simulations Laboratory: https://rensimlab.github.io
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Media Relations Contact: John Toon (404-894-6986) (jtoon@gatech.edu).
When it comes to the health effects of chronic stress, the type of stressor matters a lot. At work, most stressors are one of two types: hindrances or challenges.
Hindrances are stress factors that just get in the way and thwart performance. Examples are an abusive boss, constant interruptions, and harassment. These stressors don’t do anything to help employees. Their impact on performance is purely negative.
Meanwhile, challenges are stressors that help workers achieve, learn, and grow. Example are time pressure or a high work load. As workers successfully manage these situations, their performance improves.
“Hindrances are relatively more detrimental for health compared to challenges,” says Kimberly French. The assistant professor in the School of Psychology examined the relation between stressors and metabolic risk, as measured by levels of insulin, glucose, cholesterol, triglycerides, and other indicators of metabolic disorders that could lead to bad health outcomes, such as heart disease.
In recent analysis of data from the National Survey of Midlife Development in the United States (MIDUS) II, French and colleagues found that among three behaviors associated with chronic work stress – eating, smoking, and alcohol consumption – eating and smoking were the most likely behaviors of workers exposed to hindrances. In addition, workers chronically exposed to hindrances were more likely to eat high-sugar and high-fat foods. Consequently, exposure to hindrances was also associated with increased risk for metabolic disorders.
Workers exposed to challenges were more likely to consume alcohol. French suggests drinking alcoholic beverages may be viewed as a reward for accomplishment at work. The study was published in the Journal of Occupational and Health Psychology.
The findings have practical implications. “Eating healthy foods is really important,” French says. “Be aware of what you eat especially when you are exposed to chronic hindrances.”
Meanwhile, employers could provide healthy foods rather than unhealthy snacks when workers are under pressure.
Another tip from French: Take positive action to avoid hindrances. “If you are experiencing frequent interruptions or irritating coworkers, modify your work day or focus on different projects,” she says.
Employers, on the other hand, should design the work place to minimize hindrances and increase challenges: explore how employees can take more responsibility; make sure they are not bored.
Why is student mental health at Georgia Tech and other schools worsening?
Jan 13, 2019
The AJC
The AJC asked biology major Collin Spencer to write about mental health at Georgia Tech. In his article, he explains the status of mental health at Georgia Tech and why it continues to worsen. Yet he also highlights efforts underway to combat the problem and provide support to students struggling with depression, anxiety, and extreme stress.
Collin manages the Intercollegiate Mental Health Conference for Georgia Tech and oversees the allocation of a million-dollar fund for mental health as chair of the Joint Allocations Committee. He intends to pursue further graduate studies in public policy.
Georgia Tech scientists with expertise in microbial chemical ecology, evolution, and quantitative modeling have formed the Center for Microbial Dynamics and Infection. The center will investigate the mechanisms and consequences of microbial community dynamics in the environment and during infection. Researchers will study how microbe-microbe and microbe-host interactions are shaped by the environment and how they affect human health and ecosystem services.
“Georgia Tech has one of the nation’s strongest collection of faculty interested in understanding how microbial communities assemble and function,” says the center’s director, Marvin Whiteley, a professor in the School of Biological Sciences. “We will focus on acute societal problems, including antibiotic resistance, the onset of infection and disease, and altered biogeochemical cycles and environmental function under global change.”
Many of the most widespread chronic health problems in the U.S. – including allergies, asthma, and obesity – have been linked to an imbalance in the body’s native microbial flora. How these imbalances affect health remain largely unknown and may be the result of complex interactions between microbes. The center aims to understand these interactions.
The growing recognition that microbial communities – or microbiomes – play key roles in human health has given rise to many microbiome research centers in the U.S. “None has a goal of manipulating communities to control functional outcomes,” says Frank Stewart, the center’s associate director and an associate professor in the School of Biological Sciences.
Whiteley and Stewart are members of the Parker H. Petit Institute for Bioengineering and Bioscience.
“Our goal is to optimize the balance of interacting species to bring about positive ecological outcomes,” Stewart says. Examples of functional outcomes are breakdown of potentially harmful waste products in natural and engineered ecosystems and production of microbial chemical cocktails that serve as an animal’s defense against disease-causing bacteria.
The center hopes to be a focal point for microbial sciences in Atlanta through collaborations with academic institutions such as Emory University, federal agencies such as the Centers for Disease Control and Prevention, and private institutions such as the Children’s Healthcare of Atlanta.
Center members already are collaborating with other researchers in the Atlanta area. For example, Stewart’s team has partnered with Georgia Aquarium to examine microbe-fish-health relationships. Whiteley is associate director of the Emory-Children’s Center for Cystic Fibrosis and Airways Disease Research.
The immediate goals are “to synergize microbial sciences on campus and provide a focal point for outreach to the Atlanta community,” Whiteley says. “Then we will leverage this expertise to develop a comprehensive framework for addressing microbe-driven problems facing humanity.”
The center accentuates the “tremendous momentum for microbial sciences at Georgia Tech,” Whiteley says. “The next few years will be a lot of fun.”
Why is it coldest right after sunrise?
11Alive, January 9, 2019
It makes sense that after sunrise the sun would warm you, and yet cold temperatures continue as the sun rays begin to hit us. Greg Huey, Chair of the School of Earth and Atmospheric Sciences explains that clouds trap heat, and that the lack of clouds after sunrise are a big factor. “The less clouds and water vapor in the air, the more radiation is lost to space which enhances cooling," he says.
The more you know.
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