Three stories from three posters at the Mount David Summit

Bacteria-fighting cranberry juice, falling humans  and TMI on Facebook — those were the topics of discussion with three Bates students presenting research posters at the Mount David Summit on April 1.

Caroline Barr ’11 was among several biology majors presenting senior thesis research on the effect of cranberry juice on urinary tract infections.


While the other students looked at infections in humans, Barr chose to focus on dogs with her poster, “The Effect of Cranberry Juice on the Biofilm Formation of Canine Uropathogenic Bacteria.” Barr wants to be a veterinarian, “and my adviser, Karen Palin, said that I could pursue a canine direction with my thesis.” In both humans and canines, bacteria can form “biofilms” as a factor in disease production.

Biofilms are microbial communities enclosed in a protective matrix, and within these matrices bacteria may be more resistant to antibiotics. It is thought that cranberry juice can affect the ability of the bacteria to form biofilms by altering the bacterial surface, and this has been the focus of Barr’s work.

Barr said that the cranberry juice seemed to have some effect on cells infected with bacteria, though the mechanism is uncertain.

Often, senior thesis research is more about process and less about product. No dogs came to Bates for Barr’s thesis project (the needed urine came from a Maine veterinary clinic), but still, “it takes a lot of time to set up a research project,” Barr said, even, ironically in this case, “just to get bacteria to grow!”

In his physics poster, Hunter Archibald ’12 indirectly addressed that familiar riddle: What falls faster, a ton of bricks or a ton of feathers? Advised by Professor of Physics Mark Semon, Archibald’s project, “Terminal Velocity: The Physics of Skydiving,” explored the forces that act on objects (humans in this case) hurtling toward the ground from high in the sky.


In a vacuum, of course, objects of equal weight (those feathers and bricks) fall at the same rate. But objects falling through the atmosphere are subject to air resistance. The surprise for Archibald was learning that two forces, linear and quadratic, can place a drag on falling objects, yet not at the same time.

“You can ignore one or the other,” said Archibald, “depending on the velocity and size of the object. That is, depending on the object’s speed and size, two different formulas will express the drag force. Tiny objects falling slowly (like bits of sand through water) are subject to linear drag; high speed objects like humans are subject to quadratic drag.

Archibald says it was fun to learn free-fall trivia during his project, like how a DC-9 flight attendant survived a 33,000-foot fall in 1972 after her plane exploded. Or how terminal velocity for a falling human is around 54 meters per second, but increases to around 143 meters per second if the human adopts a streamlined “standing-up” position. Happy landings!

Katherine Brodoff ’11 presented senior thesis research that looks at the propensity of some people to post TMI (Too Much Information) on Facebook. She wondered: Do such people also have, as a group, the personality traits of impulsivity and lack of control?


Advised by Assistant Professor of Psychology Helen Boucher, Brodoff initiated her project by first having 62 Bates students complete a survey that measures self-control.

Then, Brodoff delved into their Facebook profiles, looking at their Info, Wall and Photos tabs. She grouped what she saw into seven areas of self-control, such as sexual disclosure, substance abuse and egotism.

While Brodoff’s don’t indicate a clear-cut link between self-control and TMI, she did find that people who self-reported higher self-control on the survey also tended to display more evidence of interpersonal success on Facebook, as measured by content suggesting healthy relationships with friends or significant others.

“With Facebook so new, there’s a lack of research on the topic,” Brodoff said. “We know you can judge someone’s personality by the posters and whatnot in their bedroom. So judging someone’s personality by their Facebook disclosure is next.”

View Comments