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<jats:p>Relatively few catalytic systems are able to control the stereochemistry of electronically excited organic intermediates. Here we report the discovery that a chiral Lewis acid complex can catalyze triplet energy transfer from an electronically excited photosensitizer. We applied this strategy to asymmetric [2 + 2] photocycloadditions of 2′-hydroxychalcones, using tris(bipyridyl) ruthenium(II) as a sensitizer. A variety of electrochemical, computational, and spectroscopic data rule out substrate activation by means of photoinduced electron transfer and instead support a mechanism in which Lewis acid coordination dramatically lowers the triplet energy of the chalcone substrate. We expect that this approach will enable chemists to more broadly apply their detailed understanding of chiral Lewis acid catalysis to stereocontrol in reactions involving electronically excited states.</jats:p>

<jats:title>Volcano monitoring goes into the deep</jats:title> <jats:p> Axial Seamount is a large and active submarine volcano along the Juan de Fuca midocean ridge off the coast of the western United States. Eruptions in 1998 and 2011 were followed by periods of magma recharge, making it an ideal location to include in the Ocean Observatories Initiative Cabled Array. Wilcock <jats:italic>et al.</jats:italic> present real-time seismic data from the most recent eruption in April 2015 that allow the tracking of magma before and during eruption. Nooner and Chadwick show that eruptions are predictable on the basis of deformation data. As magma pools underneath it, Axial Seamount inflates and erupts when the inflation hits a threshold. Both studies elucidate the dynamics of submarine volcanoes, which vastly outnumber their aboveground counterparts. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1395" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah5563">1395</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1399" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah4666">1399</jats:related-article> </jats:p>

<jats:title>Volcano monitoring goes into the deep</jats:title> <jats:p> Axial Seamount is a large and active submarine volcano along the Juan de Fuca midocean ridge off the coast of the western United States. Eruptions in 1998 and 2011 were followed by periods of magma recharge, making it an ideal location to include in the Ocean Observatories Initiative Cabled Array. Wilcock <jats:italic>et al.</jats:italic> present real-time seismic data from the most recent eruption in April 2015 that allow the tracking of magma before and during eruption. Nooner and Chadwick show that eruptions are predictable on the basis of deformation data. As magma pools underneath it, Axial Seamount inflates and erupts when the inflation hits a threshold. Both studies elucidate the dynamics of submarine volcanoes, which vastly outnumber their aboveground counterparts. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1395" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah5563">1395</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1399" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah4666">1399</jats:related-article> </jats:p>

<jats:title>Diamonds rock their metal roots</jats:title> <jats:p> Massive diamonds are rare, expensive, and captivating. These diamonds now appear to be distinctive not only in their size but also in their origin. Smith <jats:italic>et al.</jats:italic> probed mineral inclusions from these very large diamonds and found abundant slivers of iron metal surrounded by reducing gases. This suggests that the large diamonds grew from liquid metal in Earth's mantle. The inclusions also provide direct evidence of a long-suspected metal precipitation reaction that requires a more reducing mantle. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1403" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal1303">1403</jats:related-article> </jats:p>

<jats:title>Triggered quakes get unconventional</jats:title> <jats:p>The big earthquakes induced by human activity are mostly linked with disposal of wastewater. However, Bao and Eaton implicate hydraulic fracturing (or fracking) as the culprit in western Canada (see the Perspective by Elsworth). Fracking near Fox Creek, Alberta, reactivated faults, clustering earthquakes along the old fault traces. Fracking does not appear to cause large earthquakes in many other areas that are prone to induced seismicity. Understanding the underlying causes of seismicity in different localities is vital for developing sound regulation to limit damaging earthquakes.</jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1406" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aag2583">1406</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1380" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal2584">1380</jats:related-article> </jats:p>

<jats:title>An activity lift for platinum</jats:title> <jats:p> Platinum is an excellent but expensive catalyst for the oxygen reduction reaction (ORR), which is critical for fuel cells. Alloying platinum with other metals can create shells of platinum on cores of less expensive metals, which increases its surface exposure, and compressive strain in the layer can also boost its activity (see the Perspective by Stephens <jats:italic>et al.</jats:italic> ). Bu <jats:italic>et al.</jats:italic> produced nanoplates—platinum-lead cores covered with platinum shells—that were in tensile strain. These nanoplates had high and stable ORR activity, which theory suggests arises from the strain optimizing the platinum-oxygen bond strength. Li <jats:italic>et al.</jats:italic> optimized both the amount of surface-exposed platinum and the specific activity. They made nanowires with a nickel oxide core and a platinum shell, annealed them to the metal alloy, and then leached out the nickel to form a rough surface. The mass activity was about double the best reported values from previous studies. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1410" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah6133">1410</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1414" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf9050">1414</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1378" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal3303">1378</jats:related-article> </jats:p>

<jats:title>An activity lift for platinum</jats:title> <jats:p> Platinum is an excellent but expensive catalyst for the oxygen reduction reaction (ORR), which is critical for fuel cells. Alloying platinum with other metals can create shells of platinum on cores of less expensive metals, which increases its surface exposure, and compressive strain in the layer can also boost its activity (see the Perspective by Stephens <jats:italic>et al.</jats:italic> ). Bu <jats:italic>et al.</jats:italic> produced nanoplates—platinum-lead cores covered with platinum shells—that were in tensile strain. These nanoplates had high and stable ORR activity, which theory suggests arises from the strain optimizing the platinum-oxygen bond strength. Li <jats:italic>et al.</jats:italic> optimized both the amount of surface-exposed platinum and the specific activity. They made nanowires with a nickel oxide core and a platinum shell, annealed them to the metal alloy, and then leached out the nickel to form a rough surface. The mass activity was about double the best reported values from previous studies. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1410" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah6133">1410</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1414" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf9050">1414</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1378" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal3303">1378</jats:related-article> </jats:p>

<jats:title>Blowing harder and more often</jats:title> <jats:p> The frequency of tornado outbreaks (clusters of tornadoes) and the number of extremely powerful tornado events have been increasing over nearly the past half-century in the United States. Tippett <jats:italic>et al.</jats:italic> found that tornado outbreaks have become more common since the 1970s. This increase seems to have been driven by consistent changes in the meteorological environment that make tornadoes more likely to form. However, the changes are not necessarily those that one would expect from climate change, which makes it difficult to predict whether this trend will continue. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1419" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah7393">1419</jats:related-article> </jats:p>

<jats:title>Too many roads</jats:title> <jats:p> Roads have done much to help humanity spread across the planet and maintain global movement and trade. However, roads also damage wild areas and rapidly contribute to habitat degradation and species loss. Ibisch <jats:italic>et al.</jats:italic> cataloged the world's roads. Though most of the world is not covered by roads, it is fragmented by them, with only 7% of land patches created by roads being greater than 100 km <jats:sup>2</jats:sup> . Furthermore, environmental protection of roadless areas is insufficient, which could lead to further degradation of the world's remaining wildernesses. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1423" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aaf7166">1423</jats:related-article> </jats:p>

<jats:title>Dueling for sugars</jats:title> <jats:p> Bacteria thrive on sugar. So do plant cells. Yamada <jats:italic>et al.</jats:italic> now show how the fight for sugar plays out in the extracellular spaces around plant cells when pathogenic bacteria are invading the plant (see the Perspective by Dodds and Lagudah). In the model plant <jats:italic>Arabidopsis</jats:italic> , part of the defense response incited by the presence of pathogenic bacteria includes transcriptional and posttranscriptional regulation of sugar transporters. The resulting uptake of monosaccharides from the extracellular space makes life a little bit more difficult for the invading bacteria. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1427" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aah5692">1427</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6318" page="1377" related-article-type="in-this-issue" vol="354" xlink:href="10.1126/science.aal4273">1377</jats:related-article> </jats:p>