Volume 532 Number 7598

Editorials

Under appeal p.147

Don’t get too excited about that successful appeal against a grant rejection.

doi: 10.1038/532147b

Breeding controls p.147

Scientists must help to inform regulators wrestling with how to handle the next generation of genetically engineered crops.

doi: 10.1038/532147a

Destination Venus p.148

Findings from the Akatsuki mission should rekindle interest in Earth’s closest neighbour.

doi: 10.1038/532148a

News

News Features

News & Views

Some begging is actually bragging p.180

A meta-analysis of 143 bird species finds huge variation in parental responses to chicks' begging signals, and shows that parental strategies depend on environmental factors, such as the predictability and quality of food supplies.

doi: 10.1038/nature17317

Hard-to-reach repairs p.181

Two studies find that the molecular machinery that initiates gene transcription prevents repair proteins from accessing DNA, resulting in increased mutation rates at sites of transcription-factor binding. See Letters p.259 & p.264

doi: 10.1038/532181a

Not everything is scary about a glial scar p.182

After spinal-cord injury, cells called astrocytes form a scar that is thought to block neuronal regeneration. The finding that the scar promotes regrowth of long nerve projections called axons challenges this long-held dogma. See Article p.195

doi: 10.1038/nature17318

Quantum problems solved through games p.184

Humans are better than computers at performing certain tasks because of their intuition and superior visual processing. Video games are now being used to channel these abilities to solve problems in quantum physics. See Letter p.210

doi: 10.1038/532184a

Surprises from the sanitary engineers p.185

In mammals, microglial cells of the central nervous system are responsible for the normal clearance of dead brain cells. TAM-receptor proteins have now been found to mediate this function. See Letter p.240

doi: 10.1038/nature17881

How rain affects rock and rivers p.186

An analysis of the evolution of river channels on Hawaii's Big Island shows that a key factor is the effect of local rainfall on bedrock strength — rather than its effect on river discharge, as is often assumed. See Letter p.223

doi: 10.1038/532186a

Articles

Hourglass fermions p.189

The energy–momentum relationship of certain fermions resembles an hourglass, which is movable but unremovable; this robust property follows from the intertwining of spatial symmetries with the band theory of crystals, revised with mathematical connections to topology and cohomology.

doi: 10.1038/nature17410

Astrocyte scar formation aids central nervous system axon regeneration p.195

Sustained delivery of axon-specific growth factors not typically present in spinal cord lesions allows for robust axonal regrowth only if the astrocytic scar is present—a result that questions the prevailing dogma and suggests that astrocytic scarring aids rather than prevents central nervous system axon regeneration post injury.

doi: 10.1038/nature17623

Letters

A map of the large day–night temperature gradient of a super-Earth exoplanet p.207

A longitudinal thermal brightness map of the super-Earth exoplanet 55 Cancri e reveals strong day–night temperature contrast, indicating inefficient heat redistribution consistent with 55 Cancri e either being devoid of atmosphere or having an optically thick atmosphere with heat recirculation confined to the planetary dayside.

doi: 10.1038/nature17169

Exploring the quantum speed limit with computer games p.210

The crowd sourcing and gamification of a problem in quantum computing are described; human players succeed in solving the problem where purely numerical optimization fails, providing insight into, and a starting point for, strategies for optimization.

doi: 10.1038/nature17620

Direct observation of dynamic shear jamming in dense suspensions p.214

Dense suspensions of hard granular particles can transform from liquid-like to solid-like when perturbed; a state diagram is mapped out that reveals how this transformation can occur via dynamic jamming at sufficiently large shear stress while leaving the particle density unchanged.

doi: 10.1038/nature17167

Chemical weathering as a mechanism for the climatic control of bedrock river incision p.223

Climate-dependent chemical weathering is found to control the erodibility of bedrock-floored rivers across a rainfall gradient on the Kohala Peninsula, Hawai‘i; river erosion models that incorporate this process could improve the assessment of climatic controls from topographic data and the understanding of climatic feedbacks in landscape evolution models.

doi: 10.1038/nature17449

Post-invasion demography of prehistoric humans in South America p.232

South America was the last habitable continent to be colonized by humans; using a database of 1,147 archaeological sites and 5,464 radiocarbon dates spanning 14,000 to 2,000 years ago reveals two phases of the population history of the continent—a rapid expansion through the continent at low population sizes for over 8,000 years and then a second phase of sedentary lifestyle and exponential population growth starting around 5,000 years ago.

doi: 10.1038/nature17176

A neuronal circuit for colour vision based on rod–cone opponency p.236

Colour vision is thought to rely on the comparison of signals from cone cells in the retina, this paper identifies a class of mouse retinal ganglion cells (J-RGC) that integrates an OFF signal from ultraviolet-sensitive cones with an ON signal from green-sensitive rods, producing a colour-opponent channel that may enable animals to detect urine territory marks; the underlying circuit may also explain why humans experience a blue shift in night-time vision.

doi: 10.1038/nature17158

Nucleotide excision repair is impaired by binding of transcription factors to DNA p.264

An analysis of cancer genomic data reveals an increased rate of somatic mutations at active transcription factor binding sites located both within promoter regions and distal from genes; the increased mutation rate at these genomic regions can be explained by reduced accessibility of the protein-bound DNA to nucleotide excision repair machinery.

doi: 10.1038/nature17661