Volume 546 Issue 7657, 8 June 2017

The strange and subtle behaviour of B mesons could crack open the standard model.

Four Nature papers describing the receptor structures involved in glucose metabolism hold great promise for finding new ways to treat diabetes.

Billions of dollars are being donated without strong evidence about which ways of giving are effective, says Caroline Fiennes.

The week in science: 2–8 June 2017.

European Commission reveals widespread delays by the country’s authorities to halt spread of deadly plant disease.

Space agency takes a hard look at plans for its next big space observatory.

United Nations meeting hopes to focus artificial intelligence on sustainable development goals.

Researchers refuse to sit on evaluation panels after government bans international participation.

Withdrawal from global pact may take almost four years — which could give the winner of the 2020 presidential race the final word.

With algorithms in hand, scientists are looking to make elections in the United States more representative.

Andreas Goldthau calls for the world's 20 largest economies to take the helm in managing the transition from fossil fuels while keeping the global economy stable.

Tilli Tansey commends a chronicle tracing the pathways of the 1918 flu pandemic.

Andrew Robinson takes on a compendium of past and current ciphers ripe for decoding.

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

Gaps in the fossil record have limited our understanding of how Homo sapiens evolved. The discovery in Morocco of the earliest known H. sapiens fossils might revise our ideas about human evolution in Africa. See Letters p.289 & p.293

High-speed communication systems that use optical fibres often require hundreds of lasers. An approach that replaces these lasers with a single, ring-shaped optical device offers many technical advantages. See Letter p.274

Droplet-like assemblies of RNA in cell nuclei are associated with certain neurodegenerative diseases. Experiments reveal that these assemblies become 'frozen' gels in cells, potentially explaining their toxicity. See Article p.243

A pair of two-dimensional materials have been shown to exhibit ferromagnetism — the familiar type of magnetism found in iron bar magnets. Such materials could have applications from sensing to data storage. See Letters p.265 & p.270

Evolution favours the body form best adapted to the local environment, but it can also favour rare forms. Stickleback experiments reveal how these two selection forces can interact, and how this can limit population divergence. See Letter p.285

The geological record contains evidence of how Earth's climate responded to periodic changes in our planet's orbit and rotation. An investigation reveals how this record can be leveraged to constrain estimates of past climate dynamics.

The standard model of particle physics is incomplete, but experimental particle decays that occur through a ‘flavour-changing neutral current’ process, which show discrepancies to standard model predictions, may offer hints to the existence of new particles.

Recent measurements of B-meson decays in which tau leptons are produced might challenge the standard model assumption that interactions of leptons differ only because of their different masses.

A review of cellular strategies for nutrient sensing and acquisition, including how these strategies can be exploited by cancer cells.

Nucleotide repeat expansions create templates for multivalent base-pairing, which causes RNA to undergo a sol–gel phase transition and may explain the formation of nuclear RNA foci that are commonly observed in several neurological and neuromuscular diseases.

The structure of the GLP-1 receptor complexed with its ligand offers insight into the mechanism of class B G-protein-coupled receptor activation.

The solved crystal structure of the GLP-1 receptor bound to a truncated agonist enables the design of synthetic agonists that exhibit potent activity in vivo.

The crystal structure of the full-length human glucagon receptor reveals the essential role of the 12-residue ‘stalk’ segment and an extracellular loop in the regulation of ligand binding and receptor activation.

Intrinsic long-range ferromagnetic order is observed in few-layer Cr₂Ge₂Te₆ crystals, with a transition temperature that can be controlled using small magnetic fields.

Magneto-optical Kerr effect microscopy is used to show that monolayer chromium triiodide is an Ising ferromagnet with out-of-plane spin orientation.

Frequency combs produced by solitons in silicon-based optical microresonators are used to transmit data streams of more than 50 terabits per second in telecommunication wavelength bands.

A computational tool that combines human-like chemical understanding with ab initio methods guides the compositional choice of complex five-component metallic oxides, yielding two new complex crystal structures.

In a study using stickleback fish, negative frequency-dependent selection favours rare immigrants over common residents, weakening the effect of divergent natural selection.

New human fossils from Jebel Irhoud (Morocco) document the earliest evolutionary stage of Homo sapiens and display modern conditions of the face and mandible combined with more primative features of the neurocranium.

Thermoluminescence dating of fire-heated flint artefacts, and directly associated newly discovered remains of Homo sapiens, indicate that the Middle Stone Age site of Jebel Irhoud in Morocco is 383–247 thousand years old.

In a prairie vole (Microtus ochrogaster) model of social bonding, a functional circuit from the prefrontal cortex to nucleus accumbens is dynamically modulated to enhance females’ affiliative behaviour towards a partner.

Combined studies in MYC-driven mouse lymphomas and human Burkitt lymphoma unravel an essential role for the B-cell antigen receptor in the control of tumour B-cell fitness both in vitro and in vivo, with possible biological and clinical implications.

Random mutagenesis in haploid human cells coupled to quantitative protein measurements with different antibodies is used as a readout for individual cellular phenotypes.

Crystal structures of the human GLP-1 receptor in complex with two negative allosteric modulators reveal a common binding pocket, and, together with mutagenesis and modelling studies, further our understanding of the receptor activation mechanism.Author: Please check the wording of the following statement, which will appear online only.

Researchers outside the big institutions face a unique mix of challenges and opportunities.

A force to save coral reefs — and ocean life.

The city never sleeps.