At some point between 300 million and 1 billion years ago, a cosmic object smashed into the planet Venus, leaving a crater more than 170 miles in diameter. A team of Brown University researchers, including doctoral student Evan Bjonnes, has used the ancient impact scar to explore the possibility that Venus once had Earth-like plate tectonics. For a study published in Nature Astronomy, the researchers used computer models to recreate the impact that carved out Mead crater, Venus’s largest impact basin. Mead is surrounded by two clifflike faults — rocky ripples frozen in time after the basin-forming impact. Read more.

Sea ice is a critical indicator of changes in the Earth’s climate. A new discovery by Brown University researchers, including Karen Wang, a doctoral student in Earth, Environmental and Planetary Sciences, could provide scientists a new way to reconstruct sea ice abundance and distribution information from the ancient past, which could aid in understanding human-induced climate change happening now. In a study published in Nature Communications, the researchers show that an organic molecule often found in high-latitude ocean sediments, known as tetra-unsaturated alkenone (C37:4), is produced by one or more previously unknown species of ice-dwelling algae. As sea ice concentration ebbs and flows, so do the algae associated with it, as well as the molecules they leave behind. Read more.

For people living with opioid use disorder, the path to treatment is not always clear-cut. Sometimes, there’s no path at all. The gap between those recommended for medications for opioid use disorder — with methadone, buprenorphine or other medications prescribed — and those who ultimately receive it is wide and persisting. At the epicenter, accounting for more than one third of individuals with an opioid disorder, are Medicaid recipients. In an effort to gather information that might help to close that gap, researchers at Brown, including Alexandria Macmadu, a doctoral candidate in epidemiology, analyzed Medicaid databases to identify predictors of timely enrollment in treatment for those who experienced an opioid overdose or were diagnosed with opioid use disorder. Read more.