The zombie apocalypse won't take long. A new article in a peer-reviewed student journal finds that the zombie hordes would take Earth's population down to a mere 273 survivors in 100 days. The paper, published in the University of Leicester's Journal of Physics Special Topics, was a fanciful use of the so-called SIR model, which is used in epidemiology to simulate how diseases spread over time. It's not the first time zombies have been used as a public health metaphor. In December 2015, for example, the British medical journal The Lancet published a tongue-in-cheek paper titled "Zombie infections: epidemiology, treatment, and prevention." And a viral blog post from the Centers for Disease Control and Prevention urged zombie-apocalypse preparations as a a metaphor for real-life disaster preparedness. In the new analysis, the University of Leicester undergraduates assumed that each zombie would have 90 percent success at finding and infecting one human per day — a rate that would make