Reviews & Analysis

An artificial-intelligence method called deep learning has been used to detect signals of human-induced climate change in daily precipitation data. The results indicate that global warming has increased day-to-day rainfall variability in tropical and mid-latitude regions over the past 40 years.

The gut contents of a fossilized trilobite, Bohemolichas incola, from the Ordovician period (about 465 million years ago), were imaged by a technique called synchrotron microtomography and fully itemized. The results indicate that the animal fed indiscriminately on small shelly invertebrates and that its gut had a neutral to alkaline pH.

A data analysis shows that these destructive tropical storms are shifting earlier in the season all over the globe, owing mainly to anthropogenic climate warming. This seasonal advance could increase the likelihood of the storms overlapping with other extreme weather events, and has implications for disaster prevention.

Precise timekeeping is key to many technologies, motivating the search for more-stable reference oscillators for use as clocks. The resonant X-ray excitation of a long-lived nuclear state in scandium-45 makes it a potential reference oscillator for a nuclear clock that could surpass atomic clocks in stability and resilience against external perturbations.

Air-pollution data from pollution-monitoring stations and satellites show that wildfire smoke has influenced trends in levels of fine particulate matter in nearly three-quarters of the contiguous United States, undoing around 25% of air-quality improvements made between 2000 and 2016. Wildfires are likely to further erode air quality in the country as the climate warms.

T cells that are chronically stimulated in viral infection or cancer enter a dysfunctional state known as T-cell exhaustion. Sympathetic nerves in tissues and tumours drive T-cell exhaustion through the action of the neurotransmitter noradrenaline on the β₁-adrenergic receptors of T cells, with implications for cancer treatment.

The natural toxins portimine A and B have attracted interest for their unusual chemical architecture and potent anti-cancer activity. The first total synthesis of portimines enables the identification of portimine A’s molecular target and reveals that the toxin induces programmed cell death in human cancer cells.

Most high-throughput assays to investigate the role of genes in disease involve in vitro cell models. Now a technology that targets CRISPR–Cas9 gene editing to specific cells in mice, and analyses transcriptional effects in single nuclei, has led to fresh insights into the genes involved in 22q11.2 deletion syndrome.

Plants communicate with neighbouring plants to activate an airborne defence against aphids. However, the genetic pathway underlying this defence mechanism is unknown. A signalling cascade centred around the gaseous form of the chemical methyl salicylate was found to control this interaction between plants.

Electrochemical-reaction pathways in lithium–sulfur batteries have been studied in real time at the atomic scale using a high-resolution imaging technique. The observations revealed an unexpected collective charge-transfer process that could lead to improvements in the performance of these batteries.

Spectroscopy is widely used to characterize samples. Here, spectroscopy of a single molecule of the tropylium cation (C₇H₇⁺) presents a new approach to analysis, particularly for rare or reactive molecular ions that are probably important in interstellar chemistry.

Loss of photons over long-distance connections limits the development of quantum networks, necessitating the use of quantum ‘repeater’ systems to boost signals between network nodes. Erbium ions incorporated into calcium tungstate crystals have been found to emit photons in the telecommunications frequency band that are indistinguishable from each other, and thus show promise for use in such repeaters.

Many animals, including humans, live together and move in coordination with others, but little is known about how neurons represent or govern such complex behaviours. By studying free-flying bats, we found that neural activity in a region of the brain called the hippocampus contains a rich representation of the spatial and social environment that could support collective behaviour.

Seismic data have been used to continuously identify individual military explosions in Ukraine. Such conflict monitoring provides unprecedented details of these attacks and an objective data source that is essential for accurate war reporting and for identifying potential breaches of international law.

A centimetre-sized monolayer of the material graphene has been suspended on the surface of an aqueous electrolyte to investigate the intrinsic properties of the graphene–electrolyte interface. The results, based on optical spectroscopy, could aid the design and study of state-of-the-art electrochemical devices.

Feeding and the maintenance of internal body temperature are tightly linked in warm-blooded animals, and mammals eat more in the cold to maintain their body heat. Experiments reveal that a small nucleus in the brain’s thalamus controls feeding behaviour specifically in cold conditions by directly activating a reward centre in the brain.

Methane is a potent greenhouse gas. A global data analysis measuring the large quantities of methane released by rivers and streams shows that emissions depend on their connections to the surrounding landscape.

Cells that have been artificially reprogrammed into states similar to embryonic stem cells — known as induced pluripotent stem cells — can bear a memory of their previous history. An innovative method that incorporates a step mimicking early development yields pluripotent cells that more closely resemble those in embryos, both on a molecular and functional level.

Local human-derived stressors combine with global ocean warming to threaten coral-reef persistence. Simultaneous reduction of human-derived stressors that originate on land, such as coastal run-off, and sea-based stressors, such as fishing pressure, resulted in greater coral-reef persistence before, during and after severe heat stress than did reduction of either alone.

Analysis of immune responses to SARS-CoV-2 at single-cell resolution reveals marked differences across human populations that are caused by previous infections and genetic variation. Natural selection and past reproduction with Neanderthals contributed to these differing immune responses and disparities in COVID-19 risk.