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<jats:title>Control of magnetism in heterostructures</jats:title> <jats:p> The interface between two different materials in a heterostructure can exhibit properties unique to either of the two materials alone. A well-known example is a conducting gas that forms when LaAlO <jats:sub>3</jats:sub> is grown on SrTiO <jats:sub>3</jats:sub> , but only if the LaAlO <jats:sub>3</jats:sub> layer is at least four unit cells thick. Wang <jats:italic>et al.</jats:italic> report a similarly abrupt magnetic transition in a heterostructure formed by another oxide (LaMnO <jats:sub>3</jats:sub> ) on the same SrTiO <jats:sub>3</jats:sub> substrate. Even though bulk LaMnO <jats:sub>3</jats:sub> is an antiferromagnet, when six or more unit-cell layers of it were deposited on SrTiO <jats:sub>3</jats:sub> , it behaved like a ferromagnet. </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="6249" page="716" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa5198">716</jats:related-article> </jats:p>

<jats:title>Lower crustal deformation takes a turn</jats:title> <jats:p> Collisions creating mountain belts frequently involve a tectonic plate plunging into the mantle. Huang <jats:italic>et al.</jats:italic> connect the deformation of rock from the subducting plate to the surface topography in Taiwan (see the Perspective by Long). Subsurface deformation mapping required interpreting certain seismic wave velocities as they travel through the crust. The subsequent images of Taiwan's deep crust show two distinct layers of deformation. The bottom layer comprises the subducting slab, which is being pulled into the mantle. This mechanically couples with the upper layer of crust, compressing it into a mountain range. </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="6249" page="720" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab1879">720</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6249" page="687" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac8671">687</jats:related-article> </jats:p>

<jats:title>Tuning the band gap of black phosphorus</jats:title> <jats:p> Most materials used in electronics are semiconductors. The sizable energy gap in their electronic structure makes it easy to turn the conduction of electricity on and off. Graphene naturally lacks this band gap unless it undergoes certain modifications. Kim <jats:italic>et al.</jats:italic> studied the electronic structure of black phosphorus—a related two-dimensional material. By sprinkling potassium atoms on top of single layers of black phosphorus, the material changed from being a semiconductor to having a gapless linear dispersion similar to that of graphene. </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="6249" page="723" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa6486">723</jats:related-article> </jats:p>

<jats:title>Chirality from achiral structures</jats:title> <jats:p> The most common materials used in electronics produce only a simple optical response. Dhara <jats:italic>et al.</jats:italic> observed a complex circular photogalvanic effect in silicon nanowires, with the magnitude and direction of the induced photocurrent dependent on the polarization of the light. The specifics of the structure and geometry of the component materials are responsible for the effect. It should therefore be possible to engineer the same effect in other achiral materials and thus expand the box of enhanced functional materials for optical applications. </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="6249" page="726" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac6275">726</jats:related-article> </jats:p>

<jats:title>Cell type–specific glial networks</jats:title> <jats:p> Glial cells respond to neurotransmitters when nerve cells communicate with each other. Glial cells themselves release gliotransmitters that regulate neural synaptic transmission. Martín <jats:italic>et al.</jats:italic> studied this reciprocal relationship in a brain region called the dorsal striatum, which has two types of experimentally identifiable neurons and two types of synapses (see the Perspective by Gittis and Brasier). Subpopulations of glial cells selectively responded to the activity of one specific type of neuron. In turn, these specifically activated glial cells signaled only to the same type of neurons but not the other, indicating that glial-nerve signaling is largely cell-type specific. </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="6249" page="730" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa7945">730</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6249" page="690" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aad0678">690</jats:related-article> </jats:p>

<jats:title>Marmosets learn to talk baby-talk</jats:title> <jats:p> As human infants grow, their vocalizations change from cries, to babbles, to words. This pattern has been presumed to be absent from other primates. Indeed, the development of bird song is often regarded as a closer approximation of human language development. Takahashi <jats:italic>et al.</jats:italic> , however, observed that marmoset cries and calls in the first 2 months after birth mature in much the same way as they do in humans (see the Perspective by Margoliash and Tchernichovski). Calls changed as the infants' vocal structures grew and were influenced by feedback from their parents. </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="6249" page="734" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab1058">734</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6249" page="688" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac7860">688</jats:related-article> </jats:p>

<jats:title>Shortening the time to protection</jats:title> <jats:p> Although Ebola vaccine candidates have entered clinical trials in West Africa, there is little information available on the mechanism of protection. A single dose of the recombinant vesicular stomatitis virus–Ebola vaccine protects nonhuman primates, acting primarily through antibody responses. Marzi <jats:italic>et al.</jats:italic> found that this vaccine generates a robust immune response in macaques to a West African strain of Ebola virus within days of immunization (see the Perspective by Klenk and Becker). Innate immune responses developed in as little as 3 days and increased the chances of survival, with complete antibody protection acquired 7 days after immunization. </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="6249" page="739" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab3920">739</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6249" page="693" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aad0681">693</jats:related-article> </jats:p>

<jats:title>How to repair broken replication forks</jats:title> <jats:p> Double-strand breaks in DNA are extremely dangerous to the integrity of our genomes. Most arise from problems encountered by replication forks during duplication of genomic DNA. Break-induced replication is known to use an error-prone DNA polymerase to repair such damage. Mayle <jats:italic>et al.</jats:italic> show that cells limit error-prone DNA synthesis by preventing the DNA polymerase from inadvertently switching to a related sequence with an incorrect template. The repair of the break is achieved by using a structure-specific nuclease to prevent formation of a long single-stranded region. </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="6249" page="742" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa8391">742</jats:related-article> </jats:p>

<jats:title>Helping the next generation diversify</jats:title> <jats:p> Parasitism, including infections, can negatively affect fitness. Parents can help the next generation by increasing genetic diversity so that offspring can avoid or fight off these deleterious interactions more easily. For fruit flies, Singh <jats:italic>et al.</jats:italic> observed that in response to bacterial infection or predation by a parasitic wasp, the next generation showed increased recombination. However, this increase in genetic diversity was not due to increased recombination rates, but rather an unequal allocation of gametes that have undergone recombination. Infection therefore drives plasticity in the parental gametes, resulting in more diverse offspring. </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="6249" page="747" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab1768">747</jats:related-article> </jats:p>

<jats:p>On this week's show: How baby marmoset monkeys develop their calls and a roundup of daily news stories.</jats:p>