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<jats:title>Deep Drilling for Earthquake Clues</jats:title> <jats:p> The 2011 <jats:italic>M</jats:italic> <jats:sub>w</jats:sub> 9.0 Tohoku-Oki earthquake and tsunami were remarkable in many regards, including the rupturing of shallow trench sediments with huge associated slip (see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1178" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1246518"> <jats:bold>Wang and Kinoshita</jats:bold> </jats:related-article> ). The Japan Trench Fast Drilling Project rapid response drilling expedition sought to sample and monitor the fault zone directly through a series of boreholes. <jats:bold> Chester <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1208" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243719">1208</jats:related-article> ) describe the structure and composition of the thin fault zone, which is predominately comprised of weak clay-rich sediments. Using these same fault-zone materials, <jats:bold> Ujiie <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1211" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243485">1211</jats:related-article> ) performed high-velocity frictional experiments to determine the physical controls on the large slip that occurred during the earthquake. Finally, <jats:bold> Fulton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1214" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243641">1214</jats:related-article> ) measured in situ temperature anomalies across the fault zone for 9 months, establishing a baseline for frictional resistance and stress during and following the earthquake. </jats:p>

<jats:title>Deep Drilling for Earthquake Clues</jats:title> <jats:p> The 2011 <jats:italic>M</jats:italic> <jats:sub>w</jats:sub> 9.0 Tohoku-Oki earthquake and tsunami were remarkable in many regards, including the rupturing of shallow trench sediments with huge associated slip (see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1178" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1246518"> <jats:bold>Wang and Kinoshita</jats:bold> </jats:related-article> ). The Japan Trench Fast Drilling Project rapid response drilling expedition sought to sample and monitor the fault zone directly through a series of boreholes. <jats:bold> Chester <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1208" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243719">1208</jats:related-article> ) describe the structure and composition of the thin fault zone, which is predominately comprised of weak clay-rich sediments. Using these same fault-zone materials, <jats:bold> Ujiie <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1211" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243485">1211</jats:related-article> ) performed high-velocity frictional experiments to determine the physical controls on the large slip that occurred during the earthquake. Finally, <jats:bold> Fulton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1214" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243641">1214</jats:related-article> ) measured in situ temperature anomalies across the fault zone for 9 months, establishing a baseline for frictional resistance and stress during and following the earthquake. </jats:p>

<jats:title>Deep Drilling for Earthquake Clues</jats:title> <jats:p> The 2011 <jats:italic>M</jats:italic> <jats:sub>w</jats:sub> 9.0 Tohoku-Oki earthquake and tsunami were remarkable in many regards, including the rupturing of shallow trench sediments with huge associated slip (see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1178" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1246518"> <jats:bold>Wang and Kinoshita</jats:bold> </jats:related-article> ). The Japan Trench Fast Drilling Project rapid response drilling expedition sought to sample and monitor the fault zone directly through a series of boreholes. <jats:bold> Chester <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1208" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243719">1208</jats:related-article> ) describe the structure and composition of the thin fault zone, which is predominately comprised of weak clay-rich sediments. Using these same fault-zone materials, <jats:bold> Ujiie <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1211" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243485">1211</jats:related-article> ) performed high-velocity frictional experiments to determine the physical controls on the large slip that occurred during the earthquake. Finally, <jats:bold> Fulton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1214" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243641">1214</jats:related-article> ) measured in situ temperature anomalies across the fault zone for 9 months, establishing a baseline for frictional resistance and stress during and following the earthquake. </jats:p>

<jats:title>Giant Solar Cells</jats:title> <jats:p> Convection motions within the Sun transport heat from its interior to its surface. The hot regions are seen as granular (∼1000 kilometers across) and supergranular (∼30,000 kilometers across) cells in the Sun. Using data from the Helioseismic Magnetic Imager on the Solar Dynamics Observatory, <jats:bold> Hathaway <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1217" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1244682">1217</jats:related-article> ) found evidence for even larger cells that have long been predicted by theory but not unambiguously detected. The flows associated with these giant cells transport angular momentum toward the equator and are important for maintaining the Sun's equatorial rotation. </jats:p>

<jats:title>Toward a New Physics</jats:title> <jats:p> The search for physics beyond the Standard Model is carried out at accelerator facilities such as the Large Hadron Collider but also on a smaller scale in atomic and molecular physics experiments. One of the signatures of this “new physics” would be a nonvanishing electric dipole moment of the electron, but experiments designed to look for it need to distinguish between the signal and many potential artifacts. <jats:bold> Loh <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1220" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243683">1220</jats:related-article> ) introduce a method based on the spectroscopy of polarized molecular ions that avoids some of the sources of systematic error. </jats:p>

<jats:title>Nonlinear Optics Made Easier</jats:title> <jats:p> Nonlinear optical materials can change their optical properties in the presence of light. The nonlinearity results from the constructive addition of interacting photons, but the amount of nonlinear light produced is crucially dependent on meeting strict phase-matching conditions of the interacting photon fields. <jats:bold> Suchowski <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1223" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1244303">1223</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1182" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1247622">Kauranen</jats:related-article> </jats:bold> ) now show that metamaterials can be designed with optical properties that relax the phase-matching requirements. At a specific wavelength where the metamaterial exhibits zero refractive index, the photons are found to interact nonlinearly with the phasematching done automatically. </jats:p>

<jats:title>Epithelial Stem Cells</jats:title> <jats:p> Much remains to be known about how epithelial stem cells are generated and maintained. <jats:bold> Lim <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1226" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1239730">1226</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1183" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1248274">Frede and Jones</jats:related-article> </jats:bold> ) describe a mechanism of stem cell maintenance where epidermal stem cells generate their own self-renewing Wnt signals rather than being controlled by adjacent “niche” signals. These stem cells also express secreted Wnt inhibitors that become localized to more differentiated progeny cells. These autocrine Wnt signals and paracrine long-range Wnt inhibitors may balance stem cell self-renewal and differentiation. </jats:p>

<jats:title>Avian Affinity for H7N9</jats:title> <jats:p> Structural analyses of the binding of avian origin H7N9 influenza viruses have revealed how the receptor-binding characteristics differentiate between birds and mammals, and studies involving the use of whole viruses have suggested that the virus is acquiring human-type receptor specificity. In contrast, <jats:bold> Xu <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1230" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243761">1230</jats:related-article> ) show that the H7 hemagglutinin strongly retains its specificity for avian-type receptors by using cocrystal structures with receptor analogs and glycan binding analysis with recombinant hemagglutinin against a library of receptor analogs. Thus, current human H7N9 viruses appear to remain poorly adapted to human receptors, and additional mutations will be required to achieve specificity for human-type receptors equivalent to those of human pandemic viruses. </jats:p>

<jats:title>Dual-Duty Active Site</jats:title> <jats:p> O-linked N-acetylglucosamine transferase (OGT) catalyzes the addition of N-acetylglucosamine (GlcNac) to serine or threonine residues, influencing the localization and function of proteins. Because its activity is sensitive to the nutrient uridine diphosphate (UDP)–GlcNac, OGT has been proposed to regulate cellular responses to nutrient status. Recently, OGT in the presence of UDP-GlcNac was shown to cleave host cell factor–1 (HCF-1), a transcriptional coregulator of human cell-cycle progression. This cleavage is required for HCF-1 maturation. Through a combination of structural, biochemical, and mutagenesis studies, <jats:bold> Lazarus <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1235" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1243990">1235</jats:related-article> ) show that both cleavage and glycosylation of HCF-1 occur in the OGT active site. Cleavage occurs between cysteine and glutamine and converts the glutamine into a serine which can then be glycosylated. </jats:p>

<jats:title>Dissecting Chromosome Segregation</jats:title> <jats:p> During cell division, the centromere regions of chromosomes assemble multiprotein organelles called kinetochores that form attachments to spindle microtubules. Working in <jats:italic>Caenorhabditis elegans</jats:italic> , <jats:bold> Cheerambathur <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6163" page="1239" related-article-type="in-this-issue" vol="342" xlink:href="10.1126/science.1246232">1239</jats:related-article> , published online 14 November) describe a mechanism controlling the formation of kinetochore-spindle microtubule attachments that is essential for accurate chromosome segregation. The findings suggest the existence of crosstalk between the two major protein complexes involved in forming spindle microtubule attachments: the kinetochore dynein module, which initially captures spindle microtubules, and the Ndc80 complex, which ultimately forms the dynamic end-coupled attachments that segregate chromosomes. </jats:p>