Amid U.S. political landscape, some academics face tough choices about where to work.

Equity advocates see paths to increasing minority representation-but say it won't be easy.

Proposal to mark global changes of the 1950s now faces skeptical scientific bureaucracy.

A new documentary series traces humanity's profound effects on the world around us.

Nanoscale chromatin organization regulates gene expression. Although chromatin is notably reprogrammed during zygotic genome activation (ZGA), the organization of chromatin regulatory factors during this universal process remains unclear. In this work, we developed chromatin expansion microscopy (ChromExM) to visualize chromatin, transcription, and transcription factors in vivo. ChromExM of embryos during ZGA revealed how the pioneer factor Nanog interacts with nucleosomes and RNA polymerase II (Pol II), providing direct visualization of transcriptional elongation as string-like nanostructures. Blocking elongation led to more Pol II particles clustered around Nanog, with Pol II stalled at promoters and Nanog-bound enhancers. This led to a new model termed "kiss and kick", in which enhancer–promoter contacts are transient and released by transcriptional elongation. Our results demonstrate that ChromExM is broadly applicable to study nanoscale nuclear organization.

Perovskite solar cells (PSCs) consisting of interfacial two- and three-dimensional heterostructures that incorporate ammonium ligand intercalation have enabled rapid progress toward the goal of uniting performance with stability. However, as the field continues to seek ever-higher durability, additional tools that avoid progressive ligand intercalation are needed to minimize degradation at high temperatures. We used ammonium ligands that are nonreactive with the bulk of perovskites and investigated a library that varies ligand molecular structure systematically. We found that fluorinated aniliniums offer interfacial passivation and simultaneously minimize reactivity with perovskites. Using this approach, we report a certified quasi–steady-state power-conversion efficiency of 24.09% for inverted-structure PSCs. In an encapsulated device operating at 85°C and 50% relative humidity, we document a 1560-hour T 85 at maximum power point under 1-sun illumination.

We examined the productivity effects of a generative artificial intelligence (AI) technology, the assistive chatbot ChatGPT, in the context of midlevel professional writing tasks. In a preregistered online experiment, we assigned occupation-specific, incentivized writing tasks to 453 college-educated professionals and randomly exposed half of them to ChatGPT. Our results show that ChatGPT substantially raised productivity: The average time taken decreased by 40% and output quality rose by 18%. Inequality between workers decreased, and concern and excitement about AI temporarily rose. Workers exposed to ChatGPT during the experiment were 2 times as likely to report using it in their real job 2 weeks after the experiment and 1.6 times as likely 2 months after the experiment.

AI-predicted race variables pose risks and opportunities for studying health disparities.

In 1967, Marvin Minksy, a founder of the field of artificial intelligence (AI), made a bold prediction: “Within a generation…the problem of creating ‘artificial intelligence’ will be substantially solved.” Assuming that a generation is about 30 years, Minsky was clearly overoptimistic. But now, nearly two generations later, how close are we to the original goal of human-level (or greater) intelligence in machines?

Proposed National Research Foundation would spend $6 billion over 5 years, but is drawing mixed reactions.

Quantum networks provide the framework for quantum communication, clock synchronization, distributed quantum computing, and sensing. Implementing large-scale and practical quantum networks relies on the development of scalable architecture and integrated hardware that can coherently interconnect many remote quantum nodes by sharing multidimensional entanglement through complex-medium quantum channels. We demonstrate a multichip multidimensional quantum entanglement network based on mass-manufacturable integrated-nanophotonic quantum node chips fabricated on a silicon wafer by means of complementary metal-oxide-semiconductor processes. Using hybrid multiplexing, we show that multiple multidimensional entangled states can be distributed across multiple chips connected by few-mode fibers. We developed a technique that can efficiently retrieve multidimensional entanglement in complex-medium quantum channels, which is important for practical uses. Our work demonstrates the enabling capabilities of realizing large-scale practical chip-based quantum entanglement networks.

In the past few years, museums around the world have started to grapple with questions about the origins and ethics of their collections. This includes the acquisition and maintenance of natural history specimens. As museums examine their missions and processes, it seemed like a good time to talk to Sean Decatur, the new president of the American Museum of Natural History (AMNH) in New York City. He spoke with me (see the full conversation here) about the museum’s research and how collaborations between museums and partner nations should aspire to assemble collections that responsibly disseminate information about human cultures, the natural world, and the Universe.

Faunal turnover in Indo-Australia across Wallace’s Line is one of the most recognizable patterns in biogeography and has catalyzed debate about the role of evolutionary and geoclimatic history in biotic interchanges. Here, analysis of more than 20,000 vertebrate species with a model of geoclimate and biological diversification shows that broad precipitation tolerance and dispersal ability were key for exchange across the deep-time precipitation gradient spanning the region. Sundanian (Southeast Asian) lineages evolved in a climate similar to the humid “stepping stones” of Wallacea, facilitating colonization of the Sahulian (Australian) continental shelf. By contrast, Sahulian lineages predominantly evolved in drier conditions, hampering establishment in Sunda and shaping faunal distinctiveness. We demonstrate how the history of adaptation to past environmental conditions shapes asymmetrical colonization and global biogeographic structure.

During the early stages of human large ribosomal subunit (60 S ) biogenesis, an ensemble of assembly factors establishes and fine-tunes the essential RNA functional centers of pre-60 S particles by an unknown mechanism. Here, we report a series of cryo–electron microscopy structures of human nucleolar and nuclear pre-60 S assembly intermediates at resolutions of 2.5 to 3.2 angstroms. These structures show how protein interaction hubs tether assembly factor complexes to nucleolar particles and how guanosine triphosphatases and adenosine triphosphatase couple irreversible nucleotide hydrolysis steps to the installation of functional centers. Nuclear stages highlight how a conserved RNA-processing complex, the rixosome, couples large-scale RNA conformational changes with pre–ribosomal RNA processing by the RNA degradation machinery. Our ensemble of human pre-60 S particles provides a rich foundation with which to elucidate the molecular principles of ribosome formation.

Half-billion-year-old tunicate from western Utah "looks like it died yesterday".

In Trypanosoma brucei , the editosome, composed of RNA-editing substrate-binding complex (RESC) and RNA-editing catalytic complex (RECC), orchestrates guide RNA (gRNA)–programmed editing to recode cryptic mitochondrial transcripts into messenger RNAs (mRNAs). The mechanism of information transfer from gRNA to mRNA is unclear owing to a lack of high-resolution structures for these complexes. With cryo–electron microscopy and functional studies, we have captured gRNA-stabilizing RESC-A and gRNA-mRNA–binding RESC-B and RESC-C particles. RESC-A sequesters gRNA termini, thus promoting hairpin formation and blocking mRNA access. The conversion of RESC-A into RESC-B or -C unfolds gRNA and allows mRNA selection. The ensuing gRNA-mRNA duplex protrudes from RESC-B, likely exposing editing sites to RECC-catalyzed cleavage, uridine insertion or deletion, and ligation. Our work reveals a remodeling event facilitating gRNA-mRNA hybridization and assembly of a macromolecular substrate for the editosome’s catalytic modality.