Volume 532 Issue 7598, 14 April 2016

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

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

Statistical and biological methods are available to probe why the prevalence of obesity has risen more in some countries than in others, says John Frank.

Human embryos made HIV-resistant; reusable rocket lands on ship; Pfizer calls off merger with Allergan.

Scientists warn vaccine stocks would be overwhelmed in the event of large urban outbreaks.

Streaked acidic clouds and a bow shape in the atmosphere are among Akatsuki’s findings.

Committee begins study to guide oversight of modified organisms.

A British scientist successfully appealed against an unfavourable grant review — but the road to victory can be paved with challenges.

Revelation could have implications for how scientists approach quantum problems.

The next frontier in cancer immunotherapy lies in combining it with other treatments. Scientists are trying to get the mix just right.

Tumours are subject to the same rules of natural selection as any other living thing. Clinicians are now putting that knowledge to use.

Advances in quantum communication will come from investment in hybrid technologies, explain Stefano Pirandola and Samuel L. Braunstein.

The CRISPR–Cas9 patent battle demonstrates how overzealous efforts to commercialize technology can damage science, writes Jacob S. Sherkow.

John M. Marzluff extols a rich history of ornithology's debt to egg collecting.

Barbara Kiser reviews five of the week's best science picks.

Joan B. Silk examines Frans de Waal's treatise on the evolution of animal intelligence.

A founding father of game theory.

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.

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

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

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

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

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

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.

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.

An injury-dependent enhancer element is identified that activates gene expression in regenerating zebrafish tissues and can be engineered into DNA constructs that increase tissue regenerative capacity; the element is also active in injured mouse tissue.

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.

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.

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.

A combination of photoredox and asymmetric organic catalysis enables enantioselective radical conjugate additions to β,β-disubstituted cyclic enones to construct quaternary carbon stereocentres with high fidelity.

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.

Phylogenetic methods were applied to a cross-cultural database of traditional Austronesian societies to test the link between ritual human sacrifice and the origins of social hierarchy—the presence of sacrifice in a society stabilized social stratification and promoted inherited class systems.

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.

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.

Microglial phagocytosis is required for neurogenic niche maintenance and response to injury; the TAM kinases Mer and Axl are expressed by microglia in the adult CNS, and mediate the clearance of apoptotic cells from the niche.

A study of pancreatic ductal adenocarcinoma shows that cancer cell proliferation is associated with increased expression of proteins that control programmed necrotic cell death and suppress the adaptive immune system.

Aged fibroblasts release a Wnt antagonist, sFRP2, which drives a signalling cascade in melanoma cells, leading to increased metastasis and reduced effectiveness of targeted therapy.

Malignant cells are able to survive and grow in detached conditions, despite the associated increase in reactive oxygen species; here a novel metabolic pathway used by cancer cells as they adapt to anchorage-independent growth is described.

Analysis of 1,161 cancer genomes across 14 cancer types shows that increased mutation density at gene promoters can be linked to transcription initiation activity and impairment of nucleotide excision repair.

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.

Liquid biopsies can detect cancer signs from a blood sample, without the need for invasive procedures. But further work is needed before they can become reliable diagnostic tools.

Researchers must unpick a tangle of regulations to work with personal health data.

How mathematician Cristiano Malossi came to work for IBM.

Report from the front line.