NASA’s OSIRIS-REx mission characterized the asteroid Bennu and delivered pristine samples of its regolith to Earth. Coordinated analyses of this primitive, carbonaceous material are elucidating 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, ...

Edited by Barbara J. Finlayson-Pitts, University of California, Irvine, CA, and approved December 15, 2009 (received for review October 2, 2009) The fact that nucleation takes place at sizes below the ...

Edited by Alexis T. Bell, University of California, Berkeley, CA, and approved August 14, 2019 (received for review July 26, 2019) ...

Artistic reconstruction of shallow marine faunas from the early Palaeozoic Era of North Dakota, spanning the Early (Left) to Middle (Right) Ordovician Period. Image credit: Franz Anthony (artist). The ...

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 ...

On the Anaphase Movement of ChromosomesNote: 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 ...

PNAS depends, in part, on the payment of article processing charges (APCs) to finance its operations. Papers are accepted or rejected for publication and published solely on the basis of merit. For ...

COMMUTATORS OF SINGULAR INTEGRAL OPERATORS*Teasing out biochemical information from ancient organic-rich sediments, notably the timing of the emergence of photosynthesis relative to the inferred ...

Teasing out biochemical information from ancient organic-rich sediments, notably the timing of the emergence of photosynthesis relative to the inferred oxygenation of Earth’s atmosphere, remains a ...

We explore the key differences between the main social media platforms and how they are likely to influence information spreading and the formation of echo chambers. To assess the different dynamics, ...

Extracellular redox-active compounds, flavins and other quinones, have been hypothesized to play a major role in the delivery of electrons from cellular metabolic systems to extracellular insoluble ...