(Left to right): Eraxion/iStockphoto; ANGIE TREINEN; THOMAS DEERINCK, NCMIR/SCIENCE SOURCE

Top stories: Semen-dwelling viruses, password-guessing AI, and a trilobite-shaped corn maze

Artificial intelligence just made guessing your password a whole lot easier

The Equifax breach still has consumers up in arms, but if a hacker wants to access your online data by simply guessing your password, you’re probably toast in less than an hour. Now, there’s more bad news: Scientists have harnessed the power of artificial intelligence to create a program that, combined with existing tools, figured out more than a quarter of the passwords from a set of some 43 million LinkedIn profiles.

A new study is changing how scientists think about Alzheimer’s disease

How does ApoE4 do its dirty work? Since 1993, when this variant of the apolipoprotein E gene was found to multiply the risk of the most common form of Alzheimer's disease, researchers have probed its connections to β-amyloid, the dominant suspect for the cause of the illness. This protein fragment forms extracellular "plaques" that can disrupt brain signals and kill neurons. This week, however, one of the main proponents of the hypothesis that ApoE4 exacerbates amyloid pathology stunned many of his colleagues by showing that its most toxic effects may result from a damaging immune response to a different protein: tau.

Human semen can host up to 27 different viruses

When scientists discovered that the Zika virus can survive in semen for up to 6 months, people exposed to the disease—especially those hoping to have children—were horrified. It’s now known that the virus can be sexually transmitted up to 41 days. Now, a new meta-analysis has found that 26 other viruses can also live in human semen and go on to infect the bloodstream, including the viruses that cause Ebola, HIV, hepatitis B, and herpes. 

Giant trilobite crashes Wisconsin corn field

The cornucopia of corn mazes that come with autumn typically draw on sports or pop culture. But one Wisconsin farmer has grown a uniquely science-themed crop; after being approached by geologists at the University of Wisconsin’s Geology Museum in Madison, Angie Treinen modeled her maze after the state fossil, the long-extinct trilobite. The trilobite spans 146 meters from cephalon to pygidium, or head to tail, and is carved into the shape of a spiny Ceraurus trilobite instead of the plainer state fossil, Calymene.

New single-day pill for HIV treatment promises more bang for less buck

For about $75, the governments in South Africa and Kenya will soon be able to treat an HIV-infected person for 1 year with a pill taken once a day that contains a “best-in-class” combination of three antiretroviral (ARV) drugs. The backbone of the new pill is dolutegravir, a remarkably powerful and safe ARV that inhibits HIV’s integrase enzyme and has been too expensive for most poor and middle-income countries to afford. The annual per-person cost of the new pill, made by generic manufacturers, is also about $25 less than the least expensive similar triple-ARV combo pill on the market.