Catálogo de publicaciones - revistas

<jats:p> A signaling circuit that controls the release and detection of the same signaling molecule can trigger diverse behaviors in a cell population. <jats:named-content content-type="related-content"> [Also see Research Article by <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/343/6171/1242782.full">Youk and Lim</jats:ext-link> ] </jats:named-content> </jats:p>

<jats:p>The landmark studies of a brilliant but modest geneticist connected chromosomal translocations with cancer causation.</jats:p>

<jats:title>Interacting and Topological</jats:title> <jats:p> Topological insulators (TIs), which have a bandgap and a robust conducting surface state protected by time-reversal symmetry, are typically materials with weak electron-electron interaction and are well-described by band theory. A major experimental goal has been to observe such symmetry-protected topological (SPT) phases in interacting systems. <jats:bold> Wang <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="6171" page="629" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1243326">629</jats:related-article> ) used a theoretical approach to classify SPT phases of interacting fermions in three dimensions and found six other phases in addition to the noninteracting ones. The results lay the groundwork for future microscopic models and inform the experimental search for such materials. </jats:p>

<jats:title>Observing the Upturn</jats:title> <jats:p> When two parallel conducting wires are separated by a small insulating barrier, a current in one wire can generate a net charge displacement in the other by virtue of electron-electron interactions. Some of the models for this process predict a nonmonotonic temperature dependence of the resulting Coulomb drag voltage, with an upturn occurring at a certain low temperature <jats:italic>T</jats:italic> *. <jats:bold> Laroche <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="6171" page="631" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1244152">631</jats:related-article> , published online 23 January) observed this upturn in a pair of vertically integrated quantum wires separated by a 15-nanometer-wide barrier. </jats:p>

<jats:title>Curving Crystals</jats:title> <jats:p> When a material with a different set of lattice parameters is grown on the surface of a crystal of a second material, the stresses at the interface can affect the growing crystal. <jats:bold> Meng <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="6171" page="634" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1244827">634</jats:related-article> ) studied the growth of colloidal crystals on top of a curved water droplet. Owing to the elastic stress caused by the bending of the crystal, strong distortions occurred in the growing crystal, but, nonetheless, large single-crystalline domains with no topological defects were formed. </jats:p>

<jats:title>Weathering Heights</jats:title> <jats:p> The production of soil is the result of chemical weathering of rocks and minerals. In regions where tectonic uplift brings fresh material to Earth's surface, erosion and weathering can accelerate. Using chemical tracers, <jats:bold> Larsen <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="6171" page="637" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1244908">637</jats:related-article> , published online 16 January; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6171" page="617" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1250173">Heimsath</jats:related-article> </jats:bold> ) measured soil production rates of over 2 millimeters per year in New Zealand's Southern Alps, which are some of the fastest uplifting mountains in the world. Because chemical weathering consumes CO <jats:sub>2</jats:sub> , these rapid rates may over time influence global climate. </jats:p>

<jats:title>Predictable Behavior</jats:title> <jats:p> Few internally forced large-scale atmospheric circulation patterns exhibit periodic behavior, and those that do are centered in the tropics. Identifying these periodic processes is important for understanding the dynamics of weather. <jats:bold>Thompson and Barnes</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6171" page="641" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1247660">641</jats:related-article> ) report the discovery of a 20- to 30-day periodicity in the atmospheric circulation in the Southern Hemisphere. The oscillation could potentially drive large-scale climate variability throughout much of the mid-latitude Southern Hemisphere. </jats:p>

<jats:title>LEAFY Evolution</jats:title> <jats:p> It is generally believed that redundancy across gene copies allows for the evolution of novel function in proteins. However, it is less clear how single-copy genes with crucial function may evolve. <jats:bold> Sayou <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="6171" page="645" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1248229">645</jats:related-article> , published online 16 January; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6171" page="623" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1250348"> <jats:bold>Kovach and Lamb</jats:bold> </jats:related-article> ) examined the evolution of the essential plant transcription factor LEAFY, which is generally found as a single-copy gene. LEAFY homologs in taxa representing the major evolutionary branches of the land plants and algae exhibited three classes of LEAFY binding sites. Structural analysis identified amino acid changes in the proteins, that were responsible for contacts with specific DNA motifs and allowed the likely effects of specific amino acid changes over the evolution of land plants to be resolved. </jats:p>

<jats:title>Sculpting Actomyosin</jats:title> <jats:p> The sculpting of embryos during development involves coordinated movement of cells in large groups. How actomyosin is controlled during such collective cell movement remains poorly understood. Working with developing <jats:italic>Xenopus</jats:italic> mesoderm, <jats:bold>Shindo and Wallingford</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6171" page="649" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1243126">649</jats:related-article> ) found that planar cell polarity proteins and septins interface with the actomyosin machinery to control collective cell movement. </jats:p>

<jats:title>Viral ESCRT</jats:title> <jats:p> The ESCRT (Endosomal Sorting Complex Required for Transport) protein complex plays a role in budding into multivesicular bodies, cytokinesis, and HIV budding, but the details of how the ESCRTs facilitate viral budding are unclear. Now, using high-resolution light and electron microscopical imaging techniques, <jats:bold> Van Engelenburg <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="6171" page="653" related-article-type="in-this-issue" vol="343" xlink:href="10.1126/science.1247786">653</jats:related-article> , published online 16 January) dissect the role for ESCRT proteins in HIV budding. The findings suggest that the ESCRT machinery required for the scission of HIV particles from infected cells is located within the core of the virus particle and not, as might have been expected based on previous work, on the cellular side of the membrane scission event involved in viral budding. </jats:p>