Catálogo de publicaciones - revistas

<jats:title>Neandertal ancestors from Pleistocene Spain</jats:title> <jats:p> The Sima de los Huesos site in Atapuerca, northern Spain, is a rich source of fossil hominin specimens. The site has now yielded further skull specimens that illuminate patterns of human evolution in Europe nearly half a million years ago. Arsuaga <jats:italic>et al.</jats:italic> studied 17 crania, including 7 that are new specimens and 6 that are more complete than before (see the Perspective by Hublin). This assemblage of specimens reveals the cranial, facial, and dental features of the Atapuerca hominins, which allows more precise evolutionary positioning of these Neandertal ancestors. </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="6190" page="1358" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1253958">1358</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6190" page="1338" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1255554">1338</jats:related-article> </jats:p>

<jats:title>Creating and erasing quantum knowledge</jats:title> <jats:p> Particles in the quantum world can also assume wavelike properties. Researchers often use photons to illustrate this particle/wave duality, but electrons interact with each other, which might make them a better choice. Weisz <jats:italic>et al.</jats:italic> used electrons to create a “quantum eraser” (see the Perspective by Feldman). By taking advantage of the electrons' interaction, the researchers first acquired information about the electrons' path—a process that destroys their wavelike properties. Next, they deliberately erased this information in order to recover the electrons' wave nature. </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="6190" page="1363" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1248459">1363</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6190" page="1344" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1255501">1344</jats:related-article> </jats:p>

<jats:title>Observing jumping domain walls</jats:title> <jats:p> Domain walls, which separate regions of opposite magnetization in a ferromagnet, have rich dynamics that are difficult to characterize in small samples. Tetienne <jats:italic>et al.</jats:italic> imaged the magnetization of a thin ferromagnetic wire and observed the jumping of a domain wall between different positions along the wire. They used a scanning magnetic microscope based on a defect in diamond. The laser light needed to operate the microscope also enabled the control of the domain wall motion by causing local heating, which made the illuminated position more likely to contain a domain wall. </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="6190" page="1366" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1250113">1366</jats:related-article> </jats:p>

<jats:title>A controlled launch for plasmons</jats:title> <jats:p> To create nanophotonic devices, engineers must combine large-scale optics with tiny nanoelectronics. Plasmons, the collective light-induced excitations of electrons at a metal's surface, can bridge that difference in size scales. Alonso-Gonzalez <jats:italic>et al.</jats:italic> placed structured gold “antennas” on top of a graphene layer to launch and propagate plasmonic excitations into the graphene. By carefully designing the antennas, the researchers could engineer the wavefronts of the plasmons and control the direction of propagation. This approach illustrates a versatile approach for the development of nanophotonics. </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="6190" page="1369" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1253202">1369</jats:related-article> </jats:p>

<jats:title>Microlattices make marvelous materials</jats:title> <jats:p> Framework or lattice structures can be remarkably strong despite their very low density. Using a very precise technique known as projection microstereolithography, Zheng <jats:italic>et al.</jats:italic> fabricated octet microlattices from polymers, metals, and ceramics. The design of the lattices meant that the individual struts making up the materials did not bend under pressure. The materials were therefore exceptionally stiff, strong, and lightweight. </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="6190" page="1373" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252291">1373</jats:related-article> </jats:p>

<jats:title>Nanoparticle lattices and surfaces</jats:title> <jats:p> The challenge of resolving the details of the surfaces or assemblies of colloidal semiconductor nanoparticles can be overcome if several characterization methods are used (see the Perspective by Boles and Talapin). Boneschanscher <jats:italic>et al.</jats:italic> examined honeycomb superlattices of lead selenide nanocrystals formed by the bonding of crystal faces using several methods, including high-resolution electron microscopy and tomography. The structure had octahedral symmetry with the nanocrystals distorted through “necking”: the expansion of the contact points between the nanocrystals. Zherebetskyy <jats:italic>et al.</jats:italic> used a combination of theoretical calculations and spectroscopic methods to study the surface layer of lead sulfide nanocrystals synthesized in water. In addition to the oleic acid groups that capped the nanocrystals, hydroxyl groups were present as well. </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="6190" page="1377" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252642">1377</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6190" page="1380" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252727">1380</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6190" page="1340" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1256197">1340</jats:related-article> </jats:p>

<jats:title>Nanoparticle lattices and surfaces</jats:title> <jats:p> The challenge of resolving the details of the surfaces or assemblies of colloidal semiconductor nanoparticles can be overcome if several characterization methods are used (see the Perspective by Boles and Talapin). Boneschanscher <jats:italic>et al.</jats:italic> examined honeycomb superlattices of lead selenide nanocrystals formed by the bonding of crystal faces using several methods, including high-resolution electron microscopy and tomography. The structure had octahedral symmetry with the nanocrystals distorted through “necking”: the expansion of the contact points between the nanocrystals. Zherebetskyy <jats:italic>et al.</jats:italic> used a combination of theoretical calculations and spectroscopic methods to study the surface layer of lead sulfide nanocrystals synthesized in water. In addition to the oleic acid groups that capped the nanocrystals, hydroxyl groups were present as well. </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="6190" page="1377" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252642">1377</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6190" page="1380" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252727">1380</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6190" page="1340" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1256197">1340</jats:related-article> </jats:p>

<jats:title>Cell fate control—a numbers game</jats:title> <jats:p> Precursor cells in adult mammalian tissues differentiate at very low rates; for example, only 10% of fat cells are replaced per year. If all precursor cells responded to the same threshold of stimulus, these low rates would not be possible. Noise in the system (variability in the abundance of key proteins in different cells) could allow only a few cells to differentiate, but then such variability would allow dedifferentiation as well, which is not observed. Ahrends <jats:italic>et al.</jats:italic> used computational modeling and protein measurements in single cells to show that multiple feedback loops in the regulatory circuits, along with noise, can allow both stable and infrequent differentiation. </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="6190" page="1384" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252079">1384</jats:related-article> </jats:p>

<jats:title>Yeast metacaspase: Grim Reaper or savior?</jats:title> <jats:p> Yeast metacaspases are structural and possibly functional homologs of caspases that execute apoptosis—programmed cell death—in higher organisms. Malmgren Hill <jats:italic>et al.</jats:italic> tested whether yeast metacaspase Mca1 acts as an executioner or beneficial protein during replicative aging of yeast (see the Perspective by Kampinga). Boosting metacaspase levels caused a substantial and robust extension of life span. This lifespan extension was only partly dependent on the caspase activity of Mca1 but required the presence of the protein disaggregase Hsp104. Consistent with a role in proteostasis, Mca1 was recruited to chaperone-enriched aggregates during aging. Mca1 increased aggregate asymmetry during yeast cytokinesis and counteracted the age-associated accumulation of inclusions. </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="6190" page="1389" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252634">1389</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6190" page="1341" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1256084">1341</jats:related-article> </jats:p>