Neither of the two competing, long-debated explanations about birth rate declines may be entirely accurate. There could be big implications for policy and programs related to family planning for many ...

Mammalian organs, including the lung and the kidney, often use a branched design to maximize their functional capacity and efficiency. Lung formation requires two developmental processes: branching ...

The study of human behavior traditionally focuses on the here and now. After all, people cannot take surveys or participate in experiments if they are not alive today. Here, we propose a way to ...

PNAS may distribute embargoed copies of an accepted article to the press prior to publication. Embargoes expire at 3:00 PM US Eastern time, Monday of the publication week. Authors may talk freely with ...

Japanese macaque (Macaca fuscata) nursing a newborn. Image credit: Angela Stojan (University of Vienna, Vienna, Austria). Birth and maternal mortality in Japanese macaques The heads of fetuses in some ...

As a signatory to the San Francisco Declaration on Research Assessment, PNAS is invested in improving the evaluation of scholarly research outputs. We track a range of article and journal metrics, ...

Numbers can be unexpectedly powerful. Suppose you must provide the last two digits of your social security number (SSN), after which you are asked how much you are willing to pay for a bottle of wine.

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 ...

Edited by Joseph Kieber, The University of North Carolina at Chapel Hill, Chapel Hill, NC; received July 29, 2024; accepted September 9, 2024 ...

PNAS is one of the world's most-cited and comprehensive multidisciplinary scientific journals, publishing more than 3,500 research papers annually. The Proceedings of the National Academy of Sciences ...

This work is supported by US NIH grant DC006212 (P.H.S. and P.X.J.), NIH BRAIN (Brain Research Through Advancing Innovative Neurotechnologies) Initiative grant 1R01NS118402 (P.X.J.), Research ...

For each novel β-defensin gene identified by using the hmmsearch program (described below), additional iterative blast searches were performed against the human and mouse databases to identify ...