Curbing climate change goes hand-in-hand with decarbonizing energy production. But how can communities continue to meet the global demand for electricity without releasing more CO2? A cadre of chemists says one solution may be hiding in an unlikely source: ammonia—the pungent, clear, nitrogen-rich gas, or liquid, that’s most often used as an agricultural fertilizer. Most of the ammonia produced in

Body and canine size dimorphism in fossils inform sociobehavioral hypotheses on human evolution and have been of interest since Darwin’s famous reflections on the subject. Here, we assemble a large dataset of fossil canines of the human clade, including all available Ardipithecus ramidus fossils recovered from the Middle Awash and Gona research areas in Ethiopia, and systematically examine canine dimorphism

Tactile nerve fibers fall into a few classes that can be readily distinguished based on their spatiotemporal response properties. Because nerve fibers reflect local skin deformations, they individually carry ambiguous signals about object features. In contrast, cortical neurons exhibit heterogeneous response properties that reflect computations applied to convergent input from multiple classes of afferents

CRISPR-Cas12a, an RNA-guided DNA targeting endonuclease, has been widely used for genome editing and nucleic acid detection. As part of the essential processes for both of these applications, the two strands of double-stranded DNA are sequentially cleaved by a single catalytic site of Cas12a, but the mechanistic details that govern the generation of complete breaks in double-stranded DNA remain to

Fishes exhibit an astounding diversity of locomotor behaviors from classic swimming with their body and fins to jumping, flying, walking, and burrowing. Fishes that use their body and caudal fin (BCF) during undulatory swimming have been traditionally divided into modes based on the length of the propulsive body wave and the ratio of head:tail oscillation amplitude: anguilliform, subcarangiform, carangiform

In nature, roots of healthy plants are colonized by multikingdom microbial communities that include bacteria, fungi, and oomycetes. A key question is how plants control the assembly of these diverse microbes in roots to maintain host–microbe homeostasis and health. Using microbiota reconstitution experiments with a set of immunocompromised Arabidopsis thaliana mutants and a multikingdom synthetic microbial

The quest for how to collectively self-organize in order to maximize the survival chances of the members of a social group requires finding an optimal compromise between maximizing the well-being of an individual and that of the group. Here we develop a minimal model describing active individuals which consume or produce, and respond to a shared resource—such as the oxygen concentration for aerotactic

Microbes typically secrete a plethora of molecules to promote niche colonization. Soil-dwelling microbes are well-known producers of antimicrobials that are exploited to outcompete microbial coinhabitants. Also, plant pathogenic microbes secrete a diversity of molecules into their environment for niche establishment. Upon plant colonization, microbial pathogens secrete so-called effector proteins that

Liquid crystals (LCs) form an extremely rich range of self-assembled topological structures with artificially or naturally created topological defects. Some of the main applications of LCs are various optical and photonic devices, where compared to their solid-state counterparts, soft photonic systems are fundamentally different in terms of unique properties such as self-assembly, self-healing, large

Biomolecular folding involves searching among myriad possibilities for the native conformation, but the elementary steps expected from theory for this search have never been detected directly. We probed the dynamics of folding at high resolution using optical tweezers, measuring individual trajectories as nucleic acid hairpins passed through the high-energy transition states that dominate kinetics

We discuss the assembly and tectonochronology of the Cycladic Blueschist Unit (CBU) in the central Aegean Sea region, Greece, as a composite, subduction-related, high-pressure (blueschist to eclogite facies) stack of nappes. Our work is based on a review of geochronologic data from the islands of Tinos, Syros and Sifnos. In addition, we present a large set of 34 new, internally consistent Rb-Sr multimineral

The Laurentide Ice Sheet was the largest global ice mass to grow and decay during the last glacial cycle (~115 ka to ~10 ka). Despite its importance for driving major changes in global mean sea level, long-term landscape evolution, and atmospheric circulation patterns, the history of the Laurentide (and neighbouring Innuitian) Ice Sheet is poorly constrained owing to sporadic preservation of stratigraphic

We here review what is known about the dunefields and fluvial systems of the Kalahari Basin in terms of geological setting and Quaternary dynamics and set out what has been hypothesized about the provenance of Kalahari sand so far. Previous work has tackled this problem by applying a limited number of techniques (mostly sediment textures and heavy minerals) to parts of the large dryland. The generally

Community policing in the global south fails to reduce crime rates or public mistrust.

The seven planets orbiting the star TRAPPIST-1 were largely spared cosmic collisions, raising questions about where these worlds got their water.

Researchers say travel restrictions in response to the newly detected coronavirus variant come too late and could even slow studies of Omicron.

Early retirement for climate-damaging power plants would also cut emissions of air pollution that endanger human health.

The extinct Haast’s eagle — known from fossils found in New Zealand — hunted like its modern relatives, but also had habits of a scavenger.

Science, Volume 374, Issue 6571, Page 1166-1166, November 2021.

ANTHROPOLOGY Aerial view of the mound of Los Morteros; the Pacific Ocean is in the background. Origin of adobe bricks Clay adobe bricks are often used in traditional earthen architecture in the Andes. The pre-Hispanic Andean origin and technological evolution of adobe bricks are unclear. Ana Cecilia Mauricio et al....

In natural environments, bacteria are frequently subject to conditions of nutrient scarcity, upon which they cease to grow (1). Nongrowing bacterial cells are faced with a multitude of stresses, including nutrient depletion, alterations in cellular pH, and protein damage. While such cells mount a general stress response that renders them resistant to a variety of environmental insults (1, 2), they

Despite having similar structures, each member of the heteromeric amino acid transporter (HAT) family shows exquisite preference for the exchange of certain amino acids. Substrate specificity determines the physiological function of each HAT and their role in human diseases. However, HAT transport preference for some amino acids over others is not yet fully understood. Using cryo–electron microscopy

Refining a theorem of Zarhin, we prove that, given a g-dimensional abelian variety X and an endomorphism u of X, there exists a matrix A∈M2g(ℤ) such that each Tate module TℓX has a ℤℓ-basis on which the action of u is given by A, and similarly for the covariant Dieudonné module if over a perfect field of characteristic p.

Double-network gels are a class of tough soft materials comprising two elastic networks with contrasting structures. The formation of a large internal damage zone ahead of the crack tip by the rupturing of the brittle network accounts for the large crack resistance of the materials. Understanding what determines the damage zone is the central question of the fracture mechanics of double-network gels

Auditory transduction is mediated by chordotonal (Cho) neurons in Drosophila larvae, but the molecular identity of the mechanotransduction (MET) channel is elusive. Here, we established a whole-cell recording system of Cho neurons and showed that two transient receptor potential vanilloid (TRPV) channels, Nanchung (NAN) and Inactive (IAV), are essential for MET currents in Cho neurons. NAN and IAV

The fragility index is a clinically meaningful metric based on modifying patient outcomes that is increasingly used to interpret the robustness of clinical trial results. The fragility index relies on a concept that explores alternative realizations of the same clinical trial by modifying patient measurements. In this article, we propose to generalize the fragility index to a family of fragility indices

A basic principle of perception is that as objects increase in distance from an observer, they also become logarithmically compressed in perception (i.e., not differentiated from one another), making them hard to distinguish. Could this basic principle apply to perhaps our most meaningful mental representation: our own sense of self? Here, we report four studies that suggest selves are increasingly

Antigen-specific peripheral tolerance is crucial to prevent the development of organ-specific autoimmunity. However, its function decoupled from thymic tolerance remains unclear. We used desmoglein 3 (Dsg3), a pemphigus antigen expressed in keratinocytes, to analyze peripheral tolerance under physiological antigen-expression conditions. Dsg3-deficient thymi were transplanted into athymic mice to create

Increasing habitat fragmentation leads to wild populations becoming small, isolated, and threatened by inbreeding depression. However, small populations may be able to purge recessive deleterious alleles as they become expressed in homozygotes, thus reducing inbreeding depression and increasing population viability. We used whole-genome sequences from 57 tigers to estimate individual inbreeding and

Normally, dendritic size is established prior to adolescence and then remains relatively constant into adulthood due to a homeostatic balance between growth and retraction pathways. However, schizophrenia is characterized by accelerated reductions of cerebral cortex gray matter volume and onset of clinical symptoms during adolescence, with reductions in layer 3 pyramidal neuron dendritic length, complexity

Age-related macular degeneration is the leading cause of blindness in older adults, but techniques are being developed to offset the worst of the damage.

A raft of approaches for preventing loss of vision owing to this disease are showing their mettle in clinical trials.

The latest science news, in brief.

Hear the biggest stories from the world of science | 01 December 2021

Understanding the structure and dynamic process of water at the solid–liquid interface is an extremely important topic in surface science, energy science and catalysis1,2,3. As model catalysts, atomically flat single-crystal electrodes exhibit well-defined surface and electric field properties, and therefore may be used to elucidate the relationship between structure and electrocatalytic activity at

Nonlinear wave–matter interactions may give rise to solitons, phenomena that feature inherent stability in wave propagation and unusual spectral characteristics. Solitons have been created in a variety of physical systems and have had important roles in a broad range of applications, including communications, spectroscopy and metrology1,2,3,4. In recent years, the realization of dissipative Kerr optical

Armoured dinosaurs are well known for their evolution of specialized tail weapons—paired tail spikes in stegosaurs and heavy tail clubs in advanced ankylosaurs1. Armoured dinosaurs from southern Gondwana are rare and enigmatic, but probably include the earliest branches of Ankylosauria2,3,4. Here we describe a mostly complete, semi-articulated skeleton of a small (approximately 2 m) armoured dinosaur

Bipedal trackways discovered in 1978 at Laetoli site G, Tanzania and dated to 3.66 million years ago are widely accepted as the oldest unequivocal evidence of obligate bipedalism in the human lineage1,2,3. Another trackway discovered two years earlier at nearby site A was partially excavated and attributed to a hominin, but curious affinities with bears (ursids) marginalized its importance to the

The practice of mathematics involves discovering patterns and using these to formulate and prove conjectures, resulting in theorems. Since the 1960s, mathematicians have used computers to assist in the discovery of patterns and formulation of conjectures1, most famously in the Birch and Swinnerton-Dyer conjecture2, a Millennium Prize Problem3. Here we provide examples of new fundamental results in

The Toll/interleukin-1 receptor (TIR) domain is a canonical component of animal and plant immune systems1,2. In plants, intracellular pathogen sensing by immune receptors triggers their TIR domains to generate a molecule that is a variant of cyclic ADP-ribose3,4. This molecule is hypothesized to mediate plant cell death through a pathway that has yet to be resolved5. TIR domains have also been shown

Pro-inflammatory T cells in the central nervous system (CNS) are causally associated with multiple demyelinating and neurodegenerative diseases1,2,3,4,5,6, but the pathways that control these responses remain unclear. Here we define a population of inflammatory group 3 innate lymphoid cells (ILC3s) that infiltrate the CNS in a mouse model of multiple sclerosis. These ILC3s are derived from the circulation

Local circuit architecture facilitates the emergence of feature selectivity in the cerebral cortex1. In the hippocampus, it remains unknown whether local computations supported by specific connectivity motifs2 regulate the spatial receptive fields of pyramidal cells3. Here we developed an in vivo electroporation method for monosynaptic retrograde tracing4 and optogenetics manipulation at single-cell

Although the role of Earth’s orbital variations in driving global climate cycles has long been recognized, their effect on evolution is hitherto unknown. The fossil remains of coccolithophores, a key calcifying phytoplankton group, enable a detailed assessment of the effect of cyclic orbital-scale climate changes on evolution because of their abundance in marine sediments and the preservation of their

Translation of the genetic code into proteins is realized through repetitions of synchronous translocation of messenger RNA (mRNA) and transfer RNAs (tRNA) through the ribosome. In eukaryotes translocation is ensured by elongation factor 2 (eEF2), which catalyses the process and actively contributes to its accuracy1. Although numerous studies point to critical roles for both the conserved eukaryotic

Mass selection into groups of like-minded individuals may be fragmenting and polarizing online society, particularly with respect to partisan differences1,2,3,4. However, our ability to measure the social makeup of online communities and in turn, to understand the social organization of online platforms, is limited by the pseudonymous, unstructured and large-scale nature of digital discussion. Here

In quantum fluids, the quantization of circulation forbids the diffusion of a vortex swirling flow seen in classical viscous fluids. Yet, accelerating quantum vortices may lose their energy into acoustic radiations1,2, similar to the way electric charges decelerate on emitting photons. The dissipation of vortex energy underlies central problems in quantum hydrodynamics3, such as the decay of quantum

Centromeric integrity is key for proper chromosome segregation during cell division1. Centromeres have unique chromatin features that are essential for centromere maintenance2. Although they are intrinsically fragile and represent hotspots for chromosomal rearrangements3, little is known about how centromere integrity in response to DNA damage is preserved. DNA repair by homologous recombination requires

A machine-learning approach to the creative side of mathematics.

As part of the EUREC4A (Elucidating the role of cloud–circulation coupling in climate) field campaign, the German research aircraft HALO (High Altitude and Long Range Research Aircraft), configured as a cloud observatory, conducted 15 research flights in the trade-wind region east of Barbados in January and February 2020. Narrative text, aircraft state data, and metadata describing HALO's operation