Formation of knots in mathematical self-avoiding random walks has been extensively studied (10 – 16). In the 1960s, Frisch and Wasserman (10) and Delbruck (11) conjectured that the probability of ...

Contributed by M. Brian Maple, July 3, 2018 (sent for review April 23, 2018; reviewed by Filip Ronning and Brian C. Sales) ...

The timeframe of prediction for eco-evolutionary dynamics ...

Edited by* William A. Goddard III, California Institute of Technology, Pasadena, CA, and approved June 26, 2012 (received for review February 27, 2012) ...

Journal Club posts are short news stories featuring a recent important, timely journal article selected by one of our Journal Club panelists, who are post-doctoral associates and graduate students in ...

The PNAS Editorial Board is made up of NAS members who are active scientists and experts in their fields. On submission, your paper is assigned to an Editorial Board member in one of the 31 NAS ...

The intrinsic fracture toughness of polymer networks, defined as the energy required to fracture a single layer of polymer chains (7), is on the order of 1∼100 Jm −2, which is much lower than the ...

The western Pacific subtropical high (WPSH) channels moisture from the tropics that underpins the East Asian summer climate. Interannual variability of the WPSH dominates climate extremes in the ...

Because ecosystem responses to such variables may depend on the type of ecosystem, its species composition and soils, abiotic variables including climate, and the magnitude of the change in drivers, ...

We study ionic current fluctuations in solid-state nanopores over a wide frequency range and present a complete description of the noise characteristics. At low frequencies (f ≲ 100 Hz) we observe ...

Nature creates the gradient structure (GS) for a purpose: to make biological systems strong and tough to survive severe natural forces. For the grain-size GS, the deformation physics is still unclear.

Chloride concentrations are increasing at a rate that threatens the availability of fresh water in the northeastern United States. Increases in roadways and deicer use are now salinizing fresh waters, ...