The snakes’ fangs are located at the back of their mouths, so the creatures are known as “rear-fanged” snakes. Ostrofsky looked at how aggressive the snakes are and compared their natures to their head and fang sizes to determine whether their fangs developed for one of two purposes –– to defend themselves or to kill prey. Then he looked at the environments in which the snakes evolved to see what their local needs were –– that is, whether they needed to defend themselves against predators more than they needed to seek prey of their own. Ostrofsky determined that the snakes’ head and fang sizes were affected to a great degree by the food that was available to them within their environments. Therefore, they had evolved to survive within their surroundings.

Kristiana Hanna
Hanna examined the two tuberculosis tests –– the Mantoux Tuberculin Skin Test and the Interferon Gamma Release Assay –– to determine which would be better to give at a Bronx medical office that sees primarily immigrants.

Doctors choose which TB test to give to patients, Hanna said. She wanted to figure out which was the best test for patients who have recently arrived in the U.S. The skin test is most commonly given, because it is quick and efficient. However, the bacille Calmette-Guerin vaccine, which is often given outside the U.S., can skew results of the skin test, leading to false positives, according to Hanna.

For the tuberculin skin test, a health-care provider injects a liquid tuberculin into the skin of the lower part of the arm, according to the Centers for Disease Control. Patients given the TST must return within two to three days to have a health-care worker look for a reaction. The health-care worker looks for a raised, hard swelling, and if present, measures its size with a ruler. Redness by itself is not considered a reaction.