Reviews & Analysis

The number of distinguishable conductance levels in memristor devices — electronic components that store information without power — has been limited by noise. An understanding of the source of the noise, and development of an effective denoising process, have now enabled 2,048 conductance levels to be achieved in memristors in large arrays fabricated in a chip factory.

Galaxy clusters are among the largest objects in the Universe to be held together by their own gravity. Most of the ordinary matter in nearby galaxy clusters is associated with a diffuse, hot-gas component. The detection of this ‘intracluster medium’ in a distant protocluster of galaxies sheds light on the cluster’s formation history.

An unprecedented data set of the body measurements of 71 million children and adolescents reveals that, in most countries, growing up in cities no longer results in the height advantage seen in most of the world in the 1990s. However, in much of sub-Saharan Africa, the growth and development advantages of urban living have been amplified.

A generalizable technique has been developed to create diverse functional inorganic membranes on the surface of various aqueous solutions. The technique ensures that the air–liquid interface receives a continuous supply of floating particles, which then assemble dynamically to form continuous membranes.

Quantum information in superconducting processors is stored as low-energy microwave photons, but transmitting this information over long distances to build a quantum network requires conversion of low-energy photons to high-energy optical photons. Laser-cooled rubidium atoms now enable conversion between photons with vastly different energies.

Since 2008, population densities of shallow-reef fishes, invertebrates and seaweeds around Australia have generally decreased near the northern limits of species’ ranges, and increased near their southern limits. Endemic invertebrates and seaweeds that prefer cold waters showed the steepest declines, and are prevented by deep-ocean barriers from moving south as temperatures rise.

Sleep in the bearded dragon Pogona vitticeps comprises two alternating stages. During one of the stages, the activities of a structure called the claustrum in the left and right hemispheres of the brain are precisely coordinated but show competitive dynamics that depend on circuits in the midbrain typically associated with vision and attention.

The zebra finch’s courtship song consists of a fixed sequence of vocal elements called syllables. A small structure in the thalamus, deep in the brain, forms connections with a set of nerve cells that become active at the beginning of syllables, thereby initiating components of the finch’s vocal repertoire.

Circadian clocks, the biochemical oscillators that are controlled by the day–night cycle, have a central role in many biological processes. The mechanism underlying the earliest form of such oscillators involves the proteins KaiB and KaiC that orchestrate the addition and removal of a phosphate group to and from KaiC.

A team spanning two continents has identified a gut–nerve conduit that confers abdominal pain in mice. Responses to activation of this conduit reveal a striking sex difference that suggests that the circuit is chronically engaged in females, perhaps explaining the strong female bias in gut pain in humans.

Our sense of smell enables us to perceive a universe of odours. Cryo-electron microscopy has provided an atomic-resolution picture of how an odour molecule is recognized by one of the hundreds of odorant receptors encoded in the human genome, providing a first view into the chemical logic of olfaction.

Long-term sea-ice measurements from the Fram Strait reveal that the dominant form of Arctic sea ice shifted around 2007, from thick and deformed ice to thinner, more uniform ice. As a result of this shift, the proportion of thick, deformed ice fell by about half. It has not yet recovered, and this is expected to affect heat and momentum exchange in the region.

Cells in which the whole genome has been doubled do not upscale protein synthesis to cope with the increase in DNA. Instead, a shortage of proteins that regulate the packing of DNA in the nucleus leads to poor segregation of DNA structures, which eventually contributes to the development of cancer.

Gene expression and features of the DNA–protein complex chromatin were mapped together at high spatial resolution in tissue sections of the mouse or human brain. This spatially resolved technology enables the examination of the spatio-temporal dynamics and regulation of gene expression in complex mammalian tissues.

The structure and function of mitochondrial networks were analysed using a combination of approaches to generate detailed maps of these cellular organelles. This analysis revealed that the mitochondria in different subtypes of lung cancer show distinct functional and structural signatures.

The compatibility of a material with its environment is important for real-world applications. A framework has been developed to translate the amino-acid sequence of segments of proteins into engineered synthetic polymers, enabling the creation of ensembles of polymers with properties matching those of mixtures of proteins.

A group of neuronal cells in the airways have been shown to detect chemicals, called prostaglandins, that are produced by immune cells during infection with a respiratory virus. Once stimulated, the neurons relay this signal to the brain. Mice in which the function of these neurons is impaired show less sickness behaviour after influenza infection than do control animals.

The rates of germline mutations — genetic changes passed from parents to their offspring — have been estimated for 68 vertebrate animal species using a method involving mother–father–offspring trios. The analysis enables mutation rates between species to be compared on a large, evolutionary scale.

Tropical deforestation affects local and regional precipitation, but the effects are uncertain and have not been determined using observations. Satellite data sets were used to show reductions in precipitation over areas of tropical forest loss, with stronger reductions seen as the deforested area expands.

Global spatial and temporal patterns of coastal phytoplankton blooms were characterized using daily satellite imaging between 2003 and 2020. These blooms were identified on the coast of 126 of the 153 ocean-bordering countries examined. The extent and frequency of blooms have increased globally over the past two decades.