At 2:50 p.m. Monday afternoon, the state of Massachusetts paused in silence in honor of fallen MIT Police Officer Sean Collier. At the same time, hundreds of people linked hands and formed a human chain on Vassar Street from the MIT Police Station to the memorial where Officer Collier was slain, outside the MIT Stata Center. Those attending formed a continuous chain stretching more than eight-tenths of a mile, blocking traffic at the busy intersection with Massachusetts Avenue.

Yesterday evening, terrible events unfolded on and near MIT's campus. An MIT Police officer, who is still unnamed, was reported shot at 10:48 p.m. near the Stata Center, and was transported to Massachusetts General Hospital where he was pronounced dead.

Shortly before 10:30 p.m. Thursday evening, an MIT police officer was shot near the Stata Center, and has been confirmed dead by the Cambridge Police Department. Though the weapon used to shoot the officer has been recovered, the shooter is still at large.

Browsing through my archive of photos, I was struck by the inherent contrast both in and between these two images. The former, shot on a sunny July 4, depicts the North Court in a state of construction-induced disarray. The photo itself, on the other hand, is clean and crisp — almost frozen.

Electronics supplier Digi-Key has recently agreed to provide a 15 percent discount and free second-day shipping to MIT departments, though students might get the discount for personal use as well.

As President Barack Obama took the oath of office at yesterday’s inauguration, hundreds of members of the MIT community looked on from lecture halls and communal spaces. Students expressed a cautious optimism for the future.