Proceedings of the National Academy of Sciences (PNAS)

Energy costs of Hannibal’s alpine crossing

Hannibal crossed the Alps with a large army containing 37 war elephants in 218 BC. Details of his route have scholars ...
PNAS

Hamiltonian Systems and Transformation in Hilbert Space

Hamiltonian Systems and Transformation in Hilbert Space Note: The article usage is presented with a three- to four-day delay and will update daily once available. Due to ths delay, usage data will not ...
PNAS

Natural Isomorphisms in Group Theory

Natural Isomorphisms in Group Theory Note: The article usage is presented with a three- to four-day delay and will update daily once available. Due to ths delay, usage data will not appear immediately ...
PNAS

An extracellular Darwinian experiment with a self-duplicating nucleic acid molecule.

Note: The article usage is presented with a three- to four-day delay and will update daily once available. Due to ths delay, usage data will not appear immediately following publication. Citation ...
PNAS

Three-stage melting of a macroscopic continuous spacetime crystal

Understanding how order emerges and breaks down is central to physics and materials science. Here, we demonstrate a macroscopic spacetime crystal—an ordered state periodic in both space and time—using ...
PNAS

Hive mind: Microbial communities and the making of memory

The President’s Council of Advisors on Science and Technology has called for a 33% increase in the number of science, technology, engineering, and mathematics (STEM) bachelor’s degrees completed per ...
PNAS

Ferment to survive: How an aerobic bacterium persists during hypoxia

Work in the lab of R.G.S. is supported by the German Research Council (grants SA 494/9-1 and SA 494/11-1). D. L. Gillett et al., Aerobic soil bacteria adapt to hypoxia by hybridizing fermentation with ...
PNAS

Unique fingerprint of marine ectotherm body size change during hyperthermal crises

Dwarfing is a common response of marine ectotherms to both anthropogenic warming and similar environmental crises throughout Earth’s history. However, the underlying mechanisms and parallels between ...
PNAS

From molecular motors to chromosome architecture

From molecular motors to chromosome architecture The President’s Council of Advisors on Science and Technology has called for a 33% increase in the number of science, technology, engineering, and ...
PNAS

Modeling autoimmune encephalitis with the human hippocampus

Modeling autoimmune encephalitis with the human hippocampus Join the global community of subscribers to PNAS, the flagship journal of the US National Academy of Sciences, a mission-driven nonprofit ...
PNAS

Plant species invasions and community composition processes

Plant species invasions and community composition processes Join the global community of subscribers to PNAS, the flagship journal of the US National Academy of Sciences, a mission-driven nonprofit ...
PNAS

Microheterogeneous singlet oxygen generation at air–water interfaces

Singlet oxygen (1 O 2) drives key photochemical reactions in the atmosphere and natural waters, yet its spatial distribution in multiphase systems remains unexplored. Here, we reveal strong microscale ...