2016 Thesis Excerpts

2016 Thesis Excerpts

Eben Eliot Bolte Bein Nudging Against Climate Change: Psychological Tools to Fix a Warming Planet
Catherine Caruso Subconcussive Blows: Putting Young Brains at Risk
Conor Gearin Evolution in the Cornbelt: How a Few Special Species Are Adapting to Industrial Agriculture
Claudia Geib Swimming Sentinels: Climate Clues from Stranded Marine Mammals
Margaux PharesYour Brain on 9 Volts: The Specter and Hype of Electrical Brain Stimulation
Kendra Pierre-Louis Geographies of Nowhere: Smeltertown and the Rising Wave of Environmental Refugees


Eben Eliot Bolte Bein
Nudging Against Climate Change: Psychological Tools to Fix a Warming Planet
Read the full thesis on MIT’s DSpace


Catherine Caruso
Subconcussive Blows: Putting Young Brains at Risk
To call the beginning of the Purdue Neurotrauma Group’s study rushed is a bit of an understatement—the researchers were notified about their grant just months before the start of football season, and realized that if they didn’t do their baseline testing immediately, the season would be lost.

The majority of the researchers’ work is done on a General Electric MRI machine, an off-white plastic tube seven feet in diameter with such thick walls that the narrow hole through the center hardly looks wide enough to accommodate a child, never mind a bulky football player.

It measures changes in blood flow through the brain, which can serve as a proxy for brain activity. That first season, the researchers had players perform a working memory task that required them to remember and match letters and patterns they saw through goggles during the scan. Prior to the scan, players also completed the imPACT, a standard computerized test of cognition and memory that many high schools use for concussion diagnosis.

The researchers assumed that combining data from helmet sensors and fMRIs with neurological and cognitive testing would allow them to better understand how the brain changes after a concussion.

Once they completed their initial round of tests, the PNG group waited for players to get concussions. After a few weeks of concussion-free football, they decided to double-check their protocols. To their shock, some of the players had imPACT results that were significantly different from their baselines. “We weren’t expecting it,” says Larry Leverenz. “There was nothing wrong with these kids. They were showing absolutely no symptoms.”

At first, they assumed it was a problem with the test. But when they retested the players, they got the same result. They then began analyzing the players’ brain imaging data.

“[Some of the players] were showing very different imaging data than they had at the beginning of the season,” Thomas Talavage says. Or, as Eric Nauman puts it, “Pretty soon [we] realized that, Holy crap, their brains are really different.”

Maybe, the researchers thought, their scanner was broken. Or maybe they weren’t administering the tests properly. One by one they ruled out every other plausible explanation before settling on the most frightening one of all: even in the absence of concussions, on the field hits were causing significant brain changes. Was it possible that an accumulation of small impacts—referred to as subconcussive blows—were just as bad as actual concussions?

When they were finally able to compare non-concussed athletes to concussed ones, they realized that not only were the brains of many of the non-concussed athletes changing, but some of them were actually changing more than the brains of the concussed players.

It seemed as if Leverenz, Nauman, and Talavage had stumbled onto something big and wholly unexpected. The researchers quickly changed course and reformulated their work in an attempt to answer a new question: can repetitive subconcussive blows cause permanent changes in teenagers’ brains?
Read the full thesis at MIT’s Dspace.


Conor Gearin
Evolution in the Cornbelt: How a Few Special Species Are Adapting to Industrial Agriculture

Brent Danielson doesn’t like studying cornfields. A wildlife biologist at Iowa State University, he’d much rather be researching animals in less corrupted landscapes like western forests or intact prairie. “I like it wild,” he said. But a friend in the agronomy department at ISA, professor Matt Liebman, cued him into an ecological mystery occurring on cropland that was too good to pass up.

Liebman uncovered something intriguing while studying weeds in agricultural fields. Something was killing off many of the weeds in his study area by eating their seeds before they could germinate. To narrow down what was scavenging, Liebman left some of the seeds as bait, surrounding them with mesh with differently sized holes. This scheme showed the animal getting to the seed was bigger than a cricket but smaller than a rabbit—most likely, a mouse. But he had no way of knowing whether this was just a few clever mice or a large population focusing on this food source. He called on Danielson for backup. The mammologist could put numbers on the mouse population and determine how much they were interacting with the agroecosystem.

Danielson found that it was the prairie deer mouse, a species native to Iowa. The prairie deer mice don’t carry the heavier headgear of their cousins, the white-footed mice, whose jaws can handle big tree nuts. Instead, deer mice specialize in eating only small insects and tiny wildflower seeds, some of which are as small as a pinhead.

As Danielson understood it at the time, the mouse needed intact prairie habitat, however limited, to survive. There was nowhere else that provided this prairie mammal with its special diet. He knew that some of them probably nested in corn fields and nibbled at corn kernels. But by and large, the species had to be surviving primarily on the edges of fields, in hedges and fencerows. There was no way, he thought, that they were living on crop fields in large numbers, which are routinely torn up by tilling, cultivation, and harvesting.

Still, the deer mouse’s success at handling weed seeds in the fields made Danielson wonder—was this species better adjusted to life on a cornfield than he had imagined? In particular, he wondered if they were benefitting from what’s called waste grain. When farmers harvest fields, a few corn kernels inevitably fall to the ground. If they germinate, they become feral corn, which is a particularly frustrating pest. Since corn is genetically modified to resist herbicides like Round Up, you can’t go out and kill feral corn with conventional sprays. They require special treatment. Sometimes, a disorderly crowd of feral corn stands in the middle of what ought to be a soybean field.

“That’s what my grandfather would call dirty beans,” Danielson said. It’s a sign that the farmer did a poor job in harvesting the previous season and left corn kernels behind.

If the deer mice were taking care of farmers’ dirty beans for them, that would be a new example of the benefits of hosting native species on agricultural land—and, more interesting for a wildlife biologist, a new example of a plains species adjusting to the agroecosystem.

Read the full thesis on MIT’s DSpace.


Claudia Geib
Swimming Sentinels: Climate Clues from Stranded Marine Mammals
Read the full thesis on MIT’s DSpace.


Margaux Phares
Your Brain on 9 Volts: The Specter and Hype of Electrical Brain Stimulation
Read the full thesis on MIT’s DSpace


Kendra Pierre-Louis
Geographies of Nowhere: Smeltertown and the Rising Wave of Environmental Refugees
Read the full thesis on MIT’s DSpace


 

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