PNAS

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Climate change may affect monarch butterfly populations if floral resources and winter habitat diminish. Click to read more. Credit: Image courtesy of Eligio Garcia-Serrano (Monarch Fund, Zitácuaro, Mexico) and Ambiente Cielo Rojo.
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Front Matter

Inner Workings: Newborn stars don’t have enough dust to build planets. What are the missing ingredients?

In the last few years, astronomers have started to get glimpses into the planet nurseries formed from newborn stars, revealing important clues as to exactly how planets form.

Image credit: Shutterstock/Neo Edmund.

Science and Culture: Can climate change games boost public understanding?

Early studies suggest that games can help participants grasp complex concepts, elicit emotional responses, and increase motivation to act.

Image credit: Keep Cool GbR.

Journal Club: Understanding how a plant makes a hook could someday improve crops

In the News

Controlled burn in mixed conifer forest near Glenbrook, Lake Tahoe. Image courtesy of Alan H. Taylor.

California fires, precipitation, and jet stream

Simulations of future California climate suggest that under high CO₂ conditions, by the late 21st century, increasing temperatures could lead to reduced snowpack, drier summers, and increased fire risk, independent of changes in winter precipitation.

Image courtesy of Alan H. Taylor.

Natural cast of a Eubrontes giganteus footprint from very shallow water lake sediments of the Hartford Basin at Dinosaur State Park, Rocky Hill, Connecticut. Image courtesy of Paul E. Olsen.

Mapping past Solar System dynamics

Researchers report a system for obtaining information about planetary motions approximately 200 million years ago, and the system could help constrain models of Solar System evolution and provide tests of gravitational models.

Image courtesy of Paul E. Olsen.

Prenatal testosterone exposure is tied to long-term socioeconomic traits. Image courtesy of iStock/Avril Morgan.

Twins and prenatal testosterone exposure

Compared with female co-twins not exposed to a male co-twin inside the uterus, female co-twins exposed to a male co-twin had 15.2% higher probability of dropping out of high school, 8.6% lower earnings at age 32, and 5.8% fewer children, according to a study.

Image courtesy of iStock/Avril Morgan.