Volume 532 Number 7599

Editorials

Monkeying around p.281

China, with its freedom from the ethical pressures experienced by researchers elsewhere, is poised to become the go-to country for work on non-human primates.

doi: 10.1038/532281a

Expect knowledge p.282

We are gratified when a politician shows that they know about science, but they all should.

doi: 10.1038/532282b

Red-tape tangle p.282

Attempts by the European Union to stimulate innovation are stifled by bureaucracy.

doi: 10.1038/532282a

News

News Features

Monkey kingdom p.300

China is positioning itself as a world leader in primate research.

doi: 10.1038/532300a

News & Views

Eating for trillions p.316

Three studies investigate the bacteria in the guts of malnourished children and find that, when this microbiota is transferred into mice, supplements of certain microbes or sugars from human breast milk can restore normal growth.

doi: 10.1038/nature17887

Misconceptions of global catastrophe p.317

American attitudes to changing weather, and therefore to climate change, have been analysed on the basis of US migration patterns since the 1970s. The findings have implications for the success of global climate policies. See Letter p.357

doi: 10.1038/532317a

An elusive DNA base in mammals p.319

The discovery of a modified version of the base adenine, known as N6-methyladenine, in mouse DNA puts paid to the theory that cytosine derivatives are the only modified bases in mammals. See Article p.329

doi: 10.1038/nature17315

Antidepressants at work p.320

Structures of the serotonin transporter protein SERT in complex with two different antidepressants shed light on how these drugs act, and point to possible targets for future drug development. See Article p.334

doi: 10.1038/nature17883

Organelle stress triggers inflammation p.321

The intracellular NOD1 and NOD2 receptors have been found to activate innate inflammation when a condition known as endoplasmic reticulum stress is induced by bacterial infection. See Letter p.394

doi: 10.1038/nature17882

Articles

Distinct bone marrow blood vessels differentially regulate haematopoiesis p.323

Bone marrow endothelial cells have dual roles in the regulation of haematopoietic stem cell maintenance and in the trafficking of blood cells between the bone marrow and the blood circulatory system; this study shows that these different functions are regulated by distinct types of endothelial blood vessels with different permeability properties, affecting the metabolic state of their neighbouring stem cells.

doi: 10.1038/nature17624

X-ray structures and mechanism of the human serotonin transporter p.334

X-ray crystal structures of the human serotonin transporter (SERT) bound to the antidepressants (S)-citalopram or paroxetine show that the antidepressants lock the protein in an outward-open conformation, and directly block serotonin from entering its binding site; the structures define the mechanism of antidepressant action in SERT and pave the way for future drug design.

doi: 10.1038/nature17629

Letters

Detection of a Cooper-pair density wave in Bi2Sr2CaCu2O8+x p.343

The quantum condensate of Cooper pairs forming a superconductor was originally conceived as being translationally invariant. In theory, however, pairs can exist with finite momentum Q, thus generating a state with a spatially modulated Cooper-pair density. Such a state has been created in ultracold 6Li gas but never observed directly in any superconductor. It is now widely hypothesized that the pseudogap phase of the copper oxide superconductors contains such a ‘pair density wave’ state. Here we report the use of nanometre-resolution scanned Josephson tunnelling microscopy to image Cooper pair tunnelling from a d-wave superconducting microscope tip to the condensate of the superconductor Bi2Sr2CaCu2O8+x. We demonstrate condensate visualization capabilities directly by using the Cooper-pair density variations surrounding zinc impurity atoms and at the Bi2Sr2CaCu2O8+x crystal supermodulation. Then, by using Fourier analysis of scanned Josephson tunnelling images, we discover the direct signature of a Cooper-pair density modulation at wavevectors QP ≈ (0.25, 0)2π/a0 and (0, 0.25)2π/a0 in Bi2Sr2CaCu2O8+x. The amplitude of these modulations is about five per cent of the background condensate density and their form factor exhibits primarily s or s′ symmetry. This phenomenology is consistent with Ginzburg–Landau theory when a charge density wave with d-symmetry form factor and wavevector QC = QP coexists with a d-symmetry superconductor; it is also predicted by several contemporary microscopic theories for the pseudogap phase.

doi: 10.1038/nature17411

The Parkfield tremors reveal slow and fast ruptures on the same asperity p.361

A tremor source on the San Andreas Fault produced an unusual sequence of low-frequency earthquakes until it was disrupted by the 2004 Parkfield earthquake; the peculiar recurrence pattern has now been modelled, showing that such slip behaviour occurs when the tremor asperity size is close to the critical nucleation size of earthquakes.

doi: 10.1038/nature17190

Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia p.366

New excavations in Liang Bua, where the remains of the ‘Hobbit’ (Homo floresiensis) were discovered, show that this diminutive human species used this cave between 190,000 and 50,000 years ago, and not until as recently as 12,000 years ago as previously interpreted; modern humans have been present in Australia since around 50,000 years ago, so whether Homo floresiensis survived long enough to witness the arrival of modern humans is still an open question.

doi: 10.1038/nature17179

Anatomy and function of an excitatory network in the visual cortex p.370

Two-photon calcium imaging and electron microscopy were used to explore the relationship between structure and function in mouse primary visual cortex, showing that layer 2/3 neurons are connected in subnetworks, that pyramidal neurons with similar orientation selectivity preferentially form synapses with each other, and that neurons with similar orientation tuning form larger synapses; this study exemplifies functional connectomics as a powerful method for studying the organizational logic of cortical networks.

doi: 10.1038/nature17192