Since 2002, PNAS has offered free and immediate access to journal content for researchers in an initial group of 81 countries, a number that has grown to over 120 lower-income countries. This access ...

A kidney cancer cell nucleus is studded with aberrant nuclear speckles (orange). Normal healthy cells tend to have the speckles clustered toward the middle. Image credit: Kate Alexander (Cold Spring ...

The rates of biological primary production before the emergence of atmospheric oxygen on Earth are thought to be low. However, mudstones from the Archean Era contain a high organic matter content, ...

Rotbarth et al. suggest that the current bimodal distribution of tree cover—dense forests (>60% cover) and sparse woodlands (<15% cover)—could transition to a more uniform “open forest” state with 30 ...

In 2010, climate scientists gathered at the Asilomar Conference Center in California, in a convening that echoed a legendary 1975 meeting in which a scientific committee came together in a exercise of ...

High-resolution measurement of Roman-era lead pollution in Arctic ice cores at the Desert Research Institute. Image credit: Jessi LeMay (Desert Research Institute, Reno, Nevada). Atmospheric lead ...

In the summer of 1977, Yosef Shiloh, then a graduate student, visited an Israeli Moroccan Jewish family with several children affected by ataxia-telangiectasia (A-T), a rare and complex genetic ...

Since the turn of the 21st century, rapid advancements in phylogenomics have significantly deepened our understanding of the tree of life, particularly for ancient divergence. A recent letter to the ...

Cable bacteria (Desulfaobulbaceae) are known for their ability to conduct electricity in the form of negatively charged electrons over many millimeters. To determine whether cable bacteria can also ...

Edited by Anthony Leggett, University of Illinois at Urbana-Champaign, Urbana, IL; received October 25, 2024; accepted December 4, 2024 ...

Jeroen A. J. M. van de Water, Tugba Bagci-Onder [...] Khalid Shah The authors note that Fig. 1J appeared incorrectly. The corrected figure and its legend appear below. The online version has been ...