Monday, August 7, 2017

Solar eclipse adds cosmic spin to Emory orientation

“It’s a strange coincidence that the moon at its distance and size almost perfectly covers the sun at its distance and size,” says Emory physicist Sidney Perkowitz. “It makes you stop and wonder — is it just a coincidence? Some people call an eclipse a religious experience. I call it cosmic.” (NASA photo)

By Carol Clark

The Emory University class of 2021 already has a unique distinction: The campus orientation day for the first-year students will occur beneath a nearly total solar eclipse. From about 2:38 to 2:41 pm on Monday, August 21, the moon will cover 97.7 percent of the sun over Atlanta.

A couple of solar telescopes will be set up on the roof of the Mathematics and Science Building between 1 and 4 pm for staff, faculty, students and their family members who want to observe the sun through them — weather permitting. But a pair of certified solar eclipse glasses, a simple pinhole camera — or even the leaves of a tree — will also make it possible to safely view the eclipse anywhere on campus where the sun is visible.

Emory first-year students plan to gather on the Quad between 2:15 and 3 pm for eclipse watching. At the Oxford campus, first-year students will gather in front of the Oxford Science Building starting at 2 pm where there will be music, a solar telescope and sun-themed snacks and drinks. The Emory Police Department will also host group eclipse viewing on the field of the Student Activity and Academic Center at the Clairmont Campus. All students, faculty and staff are welcome to attend these events.

Atlanta Science Tavern has also compiled this list of solar eclipse events in and around Atlanta. 

A total solar eclipse will sweep across a 70-mile-wide area of the United States, starting on the Pacific coast of Oregon and continuing all the way to South Carolina and the Atlantic Ocean. Even though Atlanta lies just beyond the path of totality, if the weather is clear the near-total eclipse will be worth pausing from work or school to go outside and experience.

To begin with, it’s rare. The last time the sun over Atlanta was nearly obscured by the moon was on May 31, 1984, when it was 99.7 percent covered. The New York Times described what happened as the skies began to darken about 20 minutes after noon: “The temperature dropped six degrees, flowers closed their petals, dogs howled, pigeons tucked their heads under their wings as if to sleep and the whole city was bathed in a kind of diffused light, not unlike that accompanying the approach of a severe storm.”

Emory senior  Raveena Chhibber tests out a pair of solar eclipse glasses. The neuroscience and behavioral biology major is on campus this summer working in a psychology lab and plans to take a break to witness the celestial event.

Sidney Perkowitz, Emory emeritus professor of physics, was on campus that day in 1984. He stood outside near the old physics building, now Callaway Hall, beneath a large white oak on the Quad.

“I remember a lot of people came out on the Quad, particularly around this tree,” he says. “It was a joint social experience.”

The darkening effect as the moon began to cover the sun was “eerie,” he says. “It didn’t feel exactly like twilight, it felt like something weirder was going on. It just seemed abnormal.”

Perkowitz watched the light as it passed through the leaves of the tree. “As the ambient light gets reduced, you begin to see multiple images of the crescent sun on the ground below,” Perkowitz says, explaining that each tiny space between the leaves acted as a pinhole-like opening, similar to a camera. “It’s spectacular because you see dozens and dozens of the images, filtered through the leaves.”

Aristotle observed this same phenomenon beneath a tree during a solar eclipse in the fourth century BC. The Greeks were debating at the time whether light moves in straight lines. The projection of the image of the sun through the leaves was evidence that it does, although the principles behind it would remained unresolved for nearly 2,000 years.

The white oak that Perkowitz stood beneath 33 years ago was struck by lightning in 2016 and is no longer there. There are plenty of other trees on campus, however, where eclipse watchers can stand to experience the event.

"An eclipse is a chance to stop and perceive and reflect," says Emory astronomer Erin Bonning. "It proceeds slowly and deliberately, which is not exactly the pace of modern society." (NASA graphic)

Or you can make your own pinhole projector by poking a hole in a piece of cardboard. NASA provides directions and some templates. During the eclipse, you stand with your back to the sun and hold up the cardboard so that light passes through it and hits a wall, the ground or a piece of paper that you hold up to capture a projection of the image of the sun.

Sunglasses do not provide enough protection to look directly at the sun at any time during a partial eclipse. You need special solar viewing glasses, which are available free at Fulton County libraries or can be purchased online. Beware of fakes — the American Astronomical Society provides guidance to help ensure that solar glasses are certified and safe to wear.

Horace Dale, director of the Emory Observatory, will have a limited number of solar-viewing glasses available and will set up two solar telescopes between 1 and 4 pm on the roof of the Mathematics and Science Center — if the weather holds. Take the elevator to the fifth floor of the building and follow the signs to get to the rooftop.

“If it’s just partly cloudy, we should be able to see through the breaks in the clouds,” Dale says. But even the threat of a storm, he adds, will mean having to pack up the expensive equipment to avoid it getting damaged by rain.

The special filters on the solar telescopes will make it possible to directly view the sun safely. “You’ll be able to see the filamentary structure of the sun and any flare activity on the edge of the sun,” Dale says. “There might even be a few planets that pop out.”

An Atlanta native, Dale experienced a partial eclipse here in 1970 when he was six. “I remember my dad telling me not to look at the sun,” he says. “It was a really interesting experience for me.”

Which is why Dale has already explained to the teachers of his son Joey, six, and his daughter Emma, five, that his children will not attend school on August 21. Instead they will be getting an eclipse lesson from their father. Their mother, Jessica, will also be present. A dental hygienist, she has the day off since the dentist is heading for the path of totality and will close the office.

Psychology graduate student Katy Renfroe will pause from working on her thesis to observe the partial eclipse on campus.

Astronomer Erin Bonning, director of the Emory Planetarium, will be in Clayton, Georgia — in the path of totality — during the eclipse. She will be giving a presentation for Goizueta Business School’s orientation of incoming Emory juniors at a retreat center in north Georgia. The BBA class of 2019 not only holds the distinction of being Goizueta Business School’s 100th-anniversary class — it enjoys the bonus of entering orientation with great timing in a great location.

“This will be my first total solar eclipse and I’m excited,” Bonning says. She quickly adds: “I’m cautiously excited because all astronomers know that when something really big is about to happen you don’t want the clouds to hear you talking about it. Clouds are the great enemies of astronomers.”

When Bonning was in fifth grade, in Maryland, she had fervently anticipated a near total-eclipse event. When the big moment finally arrived, it was cloudy and rainy.

She did get to witness a lunar eclipse in Atlanta around 5 am on October 8, 2014. “I got up early and walked around downtown to find a good view,” she says. “It’s breathtaking to see the Earth cast a shadow in space and the moon pass through it. It’s one thing to write down an equation for curving space time, but when you see a visual illustration of these facts it’s so much more moving. It made me feel connected to the universe.”

A woman standing near her during the lunar eclipse had a different reaction. “She said, ‘Huh. I thought it would be more impressive than that,’” Bonning recalls. “I took a deep breath and held my tongue.”

The August 21 solar eclipse is particularly special since the path of totality will stretch from sea to shining sea, across the United States. “It’s unusual because it’s taking place over such a large inhabited stretch of land,” Bonning says. “The last time we had such a grand solar eclipse across America was a century ago.”

Following are Bonning’s tips for observing the solar eclipse, whether you stay in Atlanta or travel to totality.

Plan your activity. “Don’t just hop in the car on August 21 and spontaneously head for the path of totality, or you’re going to see a partial eclipse in a traffic jam,” Bonning says. You can read more about traffic predictions here.

Don’t worry about height. “You don’t need to go to the top of a mountain or the top of a building,” Bonning says. “If you can see the sun, you can see the eclipse. It’s not like getting closer to it will give you a better view.”

Manage your expectations. “While it will be extremely cool to see the eclipse, it’s not going to look like a dragon came out of the sky and devoured the sun. That’s a myth,” Bonning says. “An eclipse is a chance to stop and perceive and reflect. It proceeds slowly and deliberately, which is not exactly the pace of modern society.”

Be in the moment. If you’re not an expert at photographing eclipses, forget trying to get the perfect selfie for social media. “You’ll be better off being open to the experience,” Bonning says. “Observe shifts in the light. Feel the temperature drop. You may notice animals behaving differently.”

Make it a fun, educational experience for kids. While you need to emphasize to young children the importance of not staring directly at the sun with the naked eye during the eclipse, you can do so in a fun way that helps them understand why. Bonning recommends parents visit this Planetary Society site, which includes directions for how to make pinhole projectors, including ones in fancy, pinhole-punched shapes.

“We’re very lucky on Earth,” Perkowitz says. “We have the largest moon of all the planets and it has all kinds of connections to love and romance and poetry. And on top of that, it has this amazing alignment with the sun that provides this incredible sight every so often.”

The moon is only a quarter of a million miles away and much smaller than Earth, he notes, while the sun is 93 million miles distant and is huge — far bigger than all of the planets in the solar system put together.

“It’s a strange coincidence that the moon at its distance and size almost perfectly covers the sun at its distance and size,” Perkowitz says. “It makes you stop and wonder — is it just a coincidence? Some people call an eclipse a religious experience. I call it cosmic.”

Thursday, August 3, 2017

Why plants represent untapped potential for innovative drug discovery

Northeastern chemistry graduate student John de la Parra poses with an aloe plant. He is collaborating with Emory ethnobotanist Cassandra Quave to explore the medicinal properties of plants. Photo by Matthew Mondoono/Northeastern University.

By Allie Nicodemo,
Northeastern University

The field of medicine has come a long way from using heroin as a cough remedy or magnet therapy to improve blood flow. These outdated methods were put to bed decades ago. But there are plenty of ancient medicinal practices that have stood the test of time. In fact, many of the life-saving pharmaceuticals we rely on today are derived from plants first discovered by indigenous communities.

Ethnobotany is the scientific study of traditional plant knowledge. It’s what gave us morphine, aspirin, and ephedrine, to name a few. And there is still untapped potential.

In a new paper published by Trends in Biotechnology, Northeastern University doctoral candidate John de la Parra and Emory University medical botanist Cassandra Quave described a new field called ethnophytotechnology. It’s the use of plant biotechnology to improve the plant-based drug discovery pipeline.

“New production, engineering, and analysis methods have made it easier to meet scientific challenges that have confronted traditionally used plant-derived medicines,” says de la Parra, who is earning his doctorate in chemistry. “It is our hope that as the field expands, rich troves of indigenous knowledge can find prominence within innovative drug discovery and production platforms.”

Quave and de la Parra are examining the vast opportunities for ethnobotany and ethnophytotechnology to promote new drug discovery and solve health challenges.

Read the full story about their recent paper on the Northeastern news site.

Related:
Brazilian peppertree packs power to knock out antibiotic-resistant bacteria

Tuesday, July 25, 2017

What UFO conspiracy theories reveal about American culture


Last spring, historian Felix Harcourt taught a class at Emory on how conspiracy theories about UFOs have shaped American culture. He began the class with a question: “How many people believe alien life exists?”

Most people in the class raised their hand. “I think so, too,” Harcourt said. “Stephen Hawking thinks so. In a giant universe there is a distinct probability that somewhere alien life has evolved. It probably looks pretty different from us, but it might be out there.”

But what about the idea that aliens have visited Earth? And stories of human complicity in those visits — usually of government complicity?

The multitude of UFO conspiracy theories are considered laughable and serious discussion of them is labeled as a cultural taboo, Harcourt said. “Even as they are treated as laughable, they’re some of the most widely believed conspiracy theories. If we go back to the sixties, Gallup polls find 96 percent of Americans had heard of UFOs, 46 percent believed that they were real. By 1973, 57 percent believed that UFOs were real. By the nineties, 71 percent believed that the government was at least hiding information about UFOs: 'They may or may not be real, but there’s definitely more going on there than the government is letting us know.' And those numbers remain relatively stable.”

A 2015 poll showed that 56 percent of American believe that UFOs are real and 45 percent believe aliens have visited Earth. “To put that into context,” Harcourt said, “in that same survey, 57 percent said that the Big Bang theory was real.”

Harcourt goes on to discuss how various UFO conspiracy theories in the 20th century have changed, often paralleling societal anxieties at the time. Click here to watch the entire class on C-SPAN’s lectures in history series.

Harcourt taught the class as part of a course, “Politics and Paranoia,” while he was a post-doctoral fellow at Emory’s Fox Center for Humanistic Inquiry.

Wednesday, July 19, 2017

Atlanta BeltLine benefits people and pollinators

Volunteers at work planting native flora along the Atlanta BeltLine walking and biking trail. (Photo by Trees Atlanta).

Judith Moen writes in Ensia Magazine about how the Atlanta BeltLine is serving as a model for the future of urban green space, driving economic, cultural and environmental renewal. Below is an excerpt from the article:

"Efforts to clean up 1,100 acres of contaminated brownfields and plant more than 3,000 indigenous trees and grasses are bringing back biodiversity not seen in decades.

"'The native plantings they have done had a tremendous positive impact,' says Berry Brosi, associate professor of environmental sciences at Emory University. 'We found enormous areas in terms of pollinator abundance.'

In fact, an unpublished study Brosi conducted found on average three times as many bee species and five times as many bees in pollinator planting sites along the BeltLine than in mowed grass.

'I noticed for the first time in my backyard, we are seeing bees, butterflies, even fireflies, which is different than four years ago,' says Chad Ralston, who lives nearby and bikes almost daily."

Read the whole article in Ensia.

Related:
Pollinator extinctions alter structure of ecological networks
The top 10 policies needed now to protect pollinators

Thursday, June 22, 2017

Mouse study suggests how hearing a warning sound turns into fearing it over time

Fluorescent tagging shows the perineuronal nets (in red) surrounding neurons (in green) of mice. Emory researchers identified a role these nets play in "capturing" an auditory fear association.

By Carol Clark

The music from the movie “Jaws” is a sound that many people have learned to associate with a fear of sharks. Just hearing the music can cause the sensation of this fear to surface, but neuroscientists do not have a full understanding of how that process works.

Now an adult mouse model reveals that changes in lattice-like structures in the brain known as perineuronal nets are necessary to “capture” an auditory fear association and “haul” it in as a longer-term memory. The journal Neuron published the findings by scientists at Emory University and McLean Hospital, a Harvard Medical School affiliate.

The findings could aid research into how to help combat veterans suffering from post-traumatic stress disorder (PTSD).

“We’ve identified a new mechanism — involving the regulation of perineuronal nets in an adult auditory cortex — that contributes to learning an association between an auditory warning and a fearful event,” says Robert Liu, a senior author of the study and an Emory biologist focused on how the brain perceives and processes sound. “It’s surprising,” he adds, “because it was previously thought that these perineuronal nets did not change in an adult brain.”

Another novel finding by the researchers: It’s not just activity in the auditory cortex during a fear-inducing experience associated with sound, but after the experience that is important for the consolidation of the memory.

“What is unexpected is that this brain activity was not in direct response to hearing the actual sound, since animals were just sitting in a quiet room during that period,” Liu says. “This finding could fit with an idea that’s been around for some time, that the way your brain consolidates memories of your day’s experiences is by replaying the events after they have happened.”

The amygdala — a region of the brain located within the temporal lobes — has long been tied to learning what stimuli can trigger emotional reactions such as fear. More recent studies have shown the firing of circuits in the auditory cortex during a threatening sound also play a role in learning what signals should set off a fear reaction.

The auditory part of the brain goes from the ear and cochlea through several stages to reach the auditory cortex — the highest neural processing level for sounds.

Perineuronal nets (PNN) are extracellular lattices that surround and stabilize neurons. During childhood development they have plasticity. “When they eventually mature, they crystalize, locking down the anatomy around the neurons and forming a kind of scaffold,” Liu says. “It’s been thought that these nets remained largely stable in adulthood.”

The mice used in the current research were trained to associate the sound of a tone with a mild shock. The animals eventually would freeze when they heard the sound, in anticipation of the mild shock. Days later, they continued to freeze at the sound even when the shock no longer followed it. The researchers found that, after the fear-association experience, a transition period lasting about four hours occured in which the PNN in the rodents’ auditory cortex changed to become stronger.

“We speculate that the strengthening of these nets — just like during development — may be putting a brake on further neural plasticity and ‘locking in’ the fear association before other sound experiences interfere with the memory,” Liu says.

When some mice in the study were given an enzyme that dissolved the PNN in the auditory cortex, they stopped remembering to freeze at the sound of the tone. “We essentially removed these nets and that appeared to prevent the fear association from consolidating in the memory, so it fell away faster,” Liu says. “It’s counterintuitive. Before we would have thought if we removed the PNN it would have increased the potential for learning the fear association by increasing the plasticity of the neurons.”

Such research could aid in the development of an intervention for PTSD. “It suggests that there may be a window of time after someone experiences a trauma that you could give them a drug to silence activity in a particular area of the brain,” Liu says. “That might prevent them from consolidating a particular traumatic memory.”

The findings also add to data about how the brain learns in general, and the relationship between receiving new information and a critical time period needed to consolidate it, he says.

First author of the study is Sunayana Banerjee, who conducted the research while she was a post-doctoral fellow at Emory. Co-senior author is Kerry Ressler – a psychiatrist focused on PTSD who was formerly with the Yerkes National Primate Research Center and Emory University and is now at Mclean Hospital and Harvard Medical School. Co-authors include research specialist Hadj Aoued and Emory undergraduates Vanessa Gutzeit, Justin Baman and Nandini Doshi. The research was supported by the National Institutes of Health grants R21MH102191 and R01DC008343 and the Office of Research Infrastructure Programs’ Primate Centers P51OD11132.

Related:
Sensory connections spill over in synesthesia
Uncovering secrets of sound symbolism